Glass Level Gauges

Bulletin B 99 - 12 E(R1)

BONTBONT®

Glass Level Gauges– reflex

Glass Level Gauges– transparent

BONTBONT®

®

®

2 BONTBONT

INDEX

FIGURE NUMBER INDEX

Page Page

General Informations ............................................3

Types, Material Schedules and Applications ...4-5

Reflex Level Gaugestype BR14-GP11 .....................................................6type BR14-G11 .....................................................42type BR12-GP11 .....................................................7type BR12-G11 .....................................................43type BR22-GP11 and BR22-GP12 ..........................8type BR23-GP11 and BR23-GP12 ..........................9type BR24-GP11 and BR24-GP12 ........................10type BR28-G41 .....................................................11type BR28-GP11 ...................................................11type BR25-GP12 ...................................................12type BR14, BR22, BR23, BR24, BR25, BR28tipo with set of valves G41,G42, GS41, GS42 .......13type BR13-G51 .....................................................14type BR26 e BR27 ................................................15

Transparent Level Gaugestype BTV-GP11, tubular glass ...............................16type BT23-GP11 and BT23-GP12 .........................17type BT24-GP11 and BT24-GP12 .........................18type BT25-GP12 ...................................................19type BT28-GP11 and BT28-GP12 .........................20type BT29-G41......................................................21

type BT23, BT24, BT25, BT28, BT29tipo with set of valves G41, G42, GS41, GS42 ......22type BT33-G52......................................................23type BT32-G52......................................................24type BT26 e BT27 .................................................28

Bicolour Level Gaugestype BC23-GP11 ...................................................26type BC24-GP11 ...................................................26type BC28-GP11 ...................................................26type BC32-G52 .....................................................26type BC1-G55 .......................................................27

Optional for Sets of Valves.................................29

Sets of Gauge Valvestype GP11, GP12 .............................................30-31type G41, G42, GS41, GS42............................32-33type G51, G52, G55 .........................................34-35

Description and Maintenance Instructionsfor reflex bodies ....................................................36for transparent bodies ...........................................37

Optionals for Gauge Bodies ..........................38-39

Bolting Torques...................................................39

Sight Glasses ......................................................40

Technical Tables .................................................41

Fig. Page

701 3702 3703 3704 3706 5714 13715 13717 15720 16721 16727 22

Fig. Page

728 22734 28737 42745 32746 32747 33748 33749 33750 33760 38761 38

Fig. Page

762 38763 38764 39765 39766 39767 39773 40776 40777 41

0.792.4 42795 42

Fig. Page

801 42802 42810 43812 03813 23

0.814.1 390.815.1 39

816 38817 38819 38820 40

Fig. Page

821 15822 28824 26825 26826 40827 40828 40829 40831 30832 30833 30

Fig. Page

834 31836 06837 07838 08839 09840 10841 12842 16843 17844 18845 19

Fig. Page

846 20850 13851 13852 22853 22854 33855 33856 11857 14858 23859 24

Fig. Page

860 27861 35862 35863 34864 4865 29866 31867 35868 21

BONT® Glass Level Gauges

3BONT

General informationFirstly we would point out that CESARE BONETTI have manufac-tured level gauges since their origin. This product has been ourindustrial speciality in Italy and all over the world since thetwenties.This catalogue describes our glass level gauges, whereasour magnetic level gauges are shown in another bulletin.When you only state the operating conditions, namely:– fluid– working pressure– working temperaturewe are able to supply the most suitable level gauge from both thepoints of view functionality and price.There are three basic types of glass level gauges:– reflex– tranparent– bicolour.

BONT reflex level gauges (Fig. 701)

Working principle:The liquid level is distinguished by the different brightness of thereflex glass in the water or in the steam space. in fact, where the-re is liquid in contact with the glass, the incidental light is refrac-ted to the inside of the gauge and absorbed; in the steam space,the incidental light is reflected against the glass grooves and theglass appears very bright (Fig. 701).

Applications:Reflex level gauges can be used in a great many cases and offergreat advantages in terms of:– low initial cost– low operating cost– easy level readingReflex level gauges cannot be used in certain cases as for example:– when the separation level between two liquids has to be read

(interface);– when besides the level indication, the observation of the liquid

colour is required;– when the process fluid is high-pressure water steam, since in

this case the glass must be protected from the solvent action ofthe boiler water by using mica shields;

– when the process fluid is such that can corrode the glass (e.g.high temperature alkaline solutions or hydrofluoric acid), sincemica shields or Polytrifluorochloroethylene shields must beused to protect the glass.

BONT transparent level gauges (Fig. 702 and 703)

Working principle:Apart from glass tube level gauges, transparent level gauges arealways fitted with two plate transparent glasses between whichthe fluid is contained. The fluid level is indicated as the result ofthe different transparence property of the two media (Fig. 702)and in some cases (for water steam), by conveying upwards on tothe surface of separat ion (between l iquid and gaseoussubstances) a source of light (Fig. 703) located at the back of thegauge, the rays of which are totally reflected down to theobserver.

Applications:Transparent level gauges are suitable for almost all installtions.In fact they permit:– the use of mica shields or Polytrifluorochloroethylene shields to

protect the glass from the corrosive action of the process fluid;– the observation of interface;– the observation of the liquid colour.

BONT bicolour level gauges (Fig. 704)

Working principle:The two opposite glasses fitted into these bicolour level gaugesare not parallel to each other. By means of a suitable illuminatorinto which a red and a green screen are fitted,– the portion of visible lenght occupied by steam appears red

whereas– the portion of visible length occupied by water appears green.The level reading is very easy even at a considerable distance.The reading of the bicolour level gauges is not affected by theblind spaces between one port-hole and the successive one (Fig.704). Details on page 26.

Applications:Their main application field is that of water steam at very highpressure.

BONT bicolour level gauges with parallel glasses (Fig. 812)

Working principle:It is a variation of transparent level gauges, however equipped withtwo reflex glasses and a back illuminator, fitted with suitable colou-red filters. The sharp reading is given by the contrast between thebright colour (usually: red) of filters in the lower part containingliquid and the colour of upper part of visible window (Fig. 812).

Applications:These level gauges are particularly suitable for liquids:– colourless,– very fluid,– non-corrosive for glasses (e.g. ammoniacal solutions, trichlo-

roethylene, water steam ut to 32 bar, etc.).

Remote Reading Level Gauges, type ITT-RDRNow these level gauges are not frequently requested becauseMagnetic Remote Reading Level Gauges are preferred (specificbulletin on request).Nevertheless they are appreciated and we still produce them.The system includes: drum connections, condensate pot, down-ward connection pipes, operating device, down gauge body.Usually bodies type BT29 or BT33 are used.Further details on request.

Request of Offer and OrderThe above descriptions are given as general information on thepossible uses of BONT level gauges.However the characteristics of the plant by same performancesshould guide the planner towards a well defined type of levelgauge, that is most suitable for the purpose.Guide elements can be:– pressure, temperature, colour, viscosity, density, corrosion

power of the process fluid,– environmental conditions as dangerous area, indoor or outdoor,

corroding atmosphere, etc.Therefore when enquiring about level gauges or when placing or-der the following information must be supplied:– type of the process fluid– maximum working pressure– maximum working temperature– centre to centre distance between the vessel connections (or

visible length required)– type of connections (flanged, threaded, etc.) and standard (UNI,

ANSI, BS, DIN, AFNOR, GOST, etc.) according to which theyare required

– optionals requested: seepage 29 for shut-off valves- page 41 for gauges bodies.

Fig. 701 reflex Fig. 702 transparent Fig. 703 transparent Fig. 704 bicolour Fig. 812 bicolour

4 BONT

Glass Level GaugesTypes, Material Schedules, Applications

In this Bulletin we give the description of our level gauges madeof metallic materials and omit that ones of non-metallic materials(Ebonite, Polypropilene, PTFE, etc.): information on request.

Max operating conditions RatingFig. MaterialType Page Press. Temp. ASME PN Fluid864 Schedule

bar °C Class bar

BR14 - GP11 652 20 211 25 Water steam, other fluids

BR 14 - G11 42

BR12 - GP11 7 52 32 236 40 Water steam

64 120BR12 - G11 43 52, 64 Other fluids (Remark 14)

40 340

BR22 - GP11 8 52 12 187 16 Water steam

28 38BR22 - GP12 8 52, 64 Other fluids (Remark 14)

17 400

BR23 - GP11 9 52 22 216 Water steam

105 38BR23 - GP12 9 52, 63, 64 600 100 Other fluids (Remark 14)

97 400

BR24 - GP11 10 52 32 236 Water steam

165 38BR24 - GP12 10 52, 63, 64 600 100 Other fluids (Remark 14)

97 400

51, 52 295 38 Any fluids, water steamBR28 - G41 11 1500 250

63, 64 200 400 excepted (Remark 14)

165 38 Any fluids, water steamBR28 - GP12 11 52, 63, 64

105 400 excepted (Remark 14)

105 38 Any fluids, water steamBR25 - GP12 12 52, 63, 64 600 100

62 400 excepted (Remark 14))

BR13 - G51 14 52 400 120 (2500) (400) Any fluids (Remark 9)

52, 55, 61 Any fluids, water steamBR26 & BR27 15 (600)

62, 63, 64 } excepted (Remark 10)

52 6 158 Water steam (Remark 11)BTV - GP11 16

52, 63, 64 12 38 Not dangerous fluids

BT23 - GP11 17 52 12 187 Water steam (Remark 12)

51 38BT23 - GP12 17 52, 63, 64 300 Other fluids (Remark 14)

30 400


105 38BT24 - GP12 18 52, 63, 64 600 100 Other fluids (Remark 14)

62 400

105 38 Any fluids, water steamBT25 - GP12 19 52, 63, 64 600 100



120 38BT28 - GP12 20 52, 63, 64 600 100 Other fluids (Remark 14)

100 400

165 38 Any fluids, water steamBT29 - G41 21 52, 63, 64 900 160


BT33 - G52 23 51 90 302 Water steam

BT32 - G52 24 51 125 326 Water steam

52, 55, 61 Any fluids, water steamBT26 & BT27 28 (600)

62, 63, 64 } excepted (Remark 10)

BC23 - GP11 52 12 187 Water steam

BC24 - GP11 26 52 20 211 Water steam

BC28 - GP11 52 40 249 Water steam

BC32 - G52 26 51 125 326 Water steam

BC1 - G55 27 51 225 374 Water steam

BONT®

5BONT

1 The tag indicating the type of the level gauge consists of twoparts that define:– the type of the level gauge body

hyphen– the type of the set of valves.

2 The level gauges having their tag followed by a “Z” are spe-cial constructions. They are suitable for operating conditionsdifferent than the ones shown in Fig. 835 for the correspon-ding standard type.

3 The nominal passage diameter in the BONT level gauges is 10mm, if not otherwise indicated. Only the gauge bodies typeBR25 and BT25 have a “large chamber” with 40 mm insidediameter and should be used where the medium boils or surges.

4 The ANSI ratings and the operating conditions shown in Fig.835 refer to size 9. For smaller sizes the operating conditionscan be higher. See diagrams on each description page orapply to us.

5 The classification shown in the column «ANSI ratings» is ap-plicable up to the temperature limit 400 °C (750 °F), becauseot the presence of glass. As shown in Fig. 835 the maximumoperating conditions are generally higher than those of ANSIrating.

6 The ANSI ratings and the operating conditions shown in Fig.835 refer to standard materials as carbon steel, stainless steel,Hastelloy and to standard glass joints. When special materials(Monel, Nickel, Ebonite, PVC, etc.) and/or special joints (purePTFE, Kel-F, etc.) are required, the maximum operating condi-tions have to be verified.

7 In Fig. 706 are indicated the Material schedules currently ma-nufactured. Boldface are given the ones of major diffusion.

08 In Fig. 706 is indicated the material of the piston for the setof valves type GP11 and GP12.– For the set of valves type G41, G42, GS41, GS42 the trim

is stainless steel AISI 316.– For the set of valves G50 the seat is Stellite hardfaced.

09 For type BR13-G51, the ANSI rating is an indication only.

10 Types BR26, BR27, BT26, BT27 are manufactured for ANSI600 rating. Anyway the operating conditions must take intoconsideration the vessel project, the welding difficulties onthe vessel of the level gauge body and especially that thereare no shut-off fittings.

11 The type BTV-GP11 has a glass tube as transparent part. Be-cause of its brittleness this level gauge can be used onlywith dangerless f lu ids, al though in presence of glassprotector.

12 In case the level gauge must be fitted directly on a steamboiler drum, please state it clearly.

13 Fig. 834 shows the level gauges fitted with the Sets type GP11, GP12. They can also be fitted with Sets G41, G42,GS41, GS42 (see pages 32 and 33).In the latter case the level gauges identification tag chan-ges after the hyphen, e.g. from BR24-GP11 to BR24-G41.See also page 13 and 22 for further informations.The maximum operating conditions, ratings and applica-tions are a function of the gauge body, therefore Fig. 864and 706 are still valid.

14 In case of fluid corrosive for the glass, please refer to ourTechnical department to define maximum allowable tempe-rature and glass protection.

Fig. 706Material Body and wetted Trim of Remarks ApplicationSchedule pieces shut-off set

(Remark 8)

SPECIAL For some types of level gauges we have normally available components made of different nuances of AISI 316, Monel 400(ASTM B164 - Class A), Hastelloy B, Hastelloy C, Incoloy 825, Carpenter 20 CB 3, Nickel, Titanium, Ebonite, PVC,Polypropilene, PTFE. Apply to us for other materials.

51 Forged carbon steel Stainless steel

52 Forged carbon steel Stainless steel Exclusion of copper, General purposesilver and their alloys

55 Forged carbon steel Stainless steel Exclusion of copper, Non corrosive fluids at lowASTM A350 LF2 AISI 316 silver and their alloys temperature up to –45,6 °C (–50 °F)

61 Forged stainless steel Stainless steel External not wetted Corrosive fluids and/orAISI 304 AISI 316 parts of stainless steel fluids at temperature lower

than –45,6 °C (–50 °F)

62 Forged stainless steel Stainless steel External not wetted Corrosive fluidsAISI 304 AISI 316 parts of carbon steel.

Exclusion of copper,silver and their alloys.

63 Forged stainless steel Stainless steel External not wetted Corrosive fluids and/orAISI 316 AISI 316 parts of stainless steel fluids at temperature lower

than –45,6 °C (–50 °F)

64 Forged stainless steel Stainless steel External not wetted Corrosive fluidsAISI 316 AISI 316 parts of carbon steel.

Exclusion of copper,silver and their alloys.

BONT®

6 BONT

Reflex Level Gaugestype BR14-GP11

Fig. 836 Type BR14-GP11

1 Connections between gauge and valves are made by end tu-bes and stuffing boxes.

2 According to the position of the shut-off valves compared withthe gauge body, the level gauge is named “right-handed” or“left-handed”. Fig. 836 shows a left-handed gauge.Each level gauge can be assembled right-handed or left-handed.Usually two level gauges (1 right and 1 left) are installed onsteam vessels.

3 According to some Steam Boiler Regulations, the visiblelength of the level gauges installed on steam boilers must benot shorter than a fixed length. Therefore the suitability ofthe smaller sizes must be checked.

4 When ordering a level gauge please state:– Centre to centre distance between connections (CC)– Standard, Size and Finishing of connections– Whether right-handed or left-handed.

5 Flanges are finished to customer prescriptions. Please state:– Standard – Size– Pressure class – FinishingThe inside passage through the gauge is 10 mm.

6 Instead of flanges, connections can be delivered with threadedends. Standard is 3/4” NPT, union. Other Standard and sizeon request.

7 BR14 gauges are fitted with reflex glasses type A (see page 40).

8 Operating conditions and material schedules on pages 4 and 5.

9 Applicable optionals and bolting torques on pages 29, 38, 39.

Size C. to C. Lenght Visible Length Weightdistance of body length of glassCC min B V G kg

3 285 178 143 165 9.04 310 203 168 190 9.45 340 233 198 220 9.86 370 263 228 250 10.37 400 293 258 280 10.88 440 333 298 320 11.39 460 353 318 340 11.7

BONT®


7BONT


01 Connections between gauge and valves are made by end tu-bes and stuffing boxes.





060Instead of flanges, connections can be delivered with threadedends. Standard is 3/4” NPT, union. Other Standard and sizeon request.



09 Applicable optionals and bolting torques on pages 29 , 38, 39.

10 Gauge bodies without valves can be supplied:– end connected (threaded or flanged)– side connected (threaded or flanged)– back connected (threaded or flanged).Please state connecting dimensions and Standard.

Size C. to C. Lenght Visible Length Weightdistance of body length of glass

CC min B V G kg

1 235 128 93 115 11.742 260 153 118 140 12.143 285 178 143 165 12.934 310 203 168 190 13.305 340 233 198 220 14.076 370 263 228 250 15.057 400 293 258 280 15.508 440 333 298 320 16.509 460 353 318 340 17.20

2 x 4 515 408 373 190 18.252 x 5 575 468 433 220 19.792 x 6 635 528 493 250 21.752 x 7 695 588 553 280 22.652 x 8 775 668 633 320 24.652 x 9 815 708 673 340 26.053 x 6 900 793 758 250 28.453 x 7 990 883 848 280 29.803 x 8 1110 1003 968 320 32.803 x 9 1170 1063 1028 340 34.904 x 7 1285 1178 1143 280 36.954 x 8 1445 1338 1303 320 40.954 x 9 1525 1418 1383 340 43.755 x 7 1580 1473 1438 280 44.305 x 8 1780 1673 1638 320 49.105 x 9 1880 1773 1738 340 52.606 x 8 2115 2008 1973 320 57.256 x 9 2235 2128 2093 340 61.457 x 9 2590 2483 2448 340 70.30

40

90

CC B V

G

200

100

BONT®

8 BONT

Reflex Level Gaugestype BR22-GP11 and BR22-GP12


01 Connections between gauge and valves are made– for BR22-GP11, by end tubes and stuffing boxes– for BR22-GP12, by NPT screwed nipples






07 BR22 gauges are fitted with reflex glasses type B (see page 40).

08 Operating conditions and material schedules on pages 4 and 5.Graph below shows rating for size 9 and smaller, combinedincluded.



11 For level gauges type BR22-G41, BR22-G42, BR22-GS41,BR22-GS42, see page 13.

Size C. to C. distance Length Visible Length WeightBR22-GP11 BR22-GP12 of body length of glass

CC min CC min B V G kg

1 235 209 128 93 115 10.052 260 234 153 118 140 10.303 285 259 178 143 165 10.804 310 284 203 168 190 11.105 340 314 233 198 220 11.356 370 344 263 228 250 12.007 400 374 293 258 280 12.208 440 414 333 298 320 12.859 460 434 353 318 340 13.05

2 x 4 515 489 408 373 190 13.902 x 5 575 549 468 433 220 14.402 x 6 635 609 528 493 250 15.702 x 7 695 669 588 553 280 16.102 x 8 775 749 668 633 320 17.402 x 9 815 789 708 673 340 17.803 x 6 900 874 793 758 250 19.403 x 7 990 964 883 848 280 20.003 x 8 1110 1084 1003 968 320 21.953 x 9 1170 1144 1063 1028 340 22.554 x 7 1285 1259 1178 1143 280 23.904 x 8 1445 1419 1338 1303 320 26.504 x 9 1525 1499 1418 1383 340 27.305 x 7 1580 1554 1473 1438 280 27.805 x 8 1780 1754 1673 1638 320 31.055 x 9 1880 1854 1773 1738 340 32.056 x 8 2115 2089 2008 1973 320 35.606 x 9 2235 2209 2128 2093 340 36.807 x 9 2590 2564 2483 2448 340 41.55

BONT®

BONT®Reflex Level Gaugestype BR23-GP11 and BR23-GP12

9BONT


01 Connections between gauge and valves are made– for BR23-GP11, by end tubes and stuffing boxes– for BR23-GP12, by NPT screwed nipples. Minimum CC

distance, shown on table is referred to 3/4” NPT connec-tions. With 1/2” NPT connections CC becomes 30 mmshorter.













1 235 237 158 93 115 11.852 260 262 183 118 140 12.303 285 287 208 143 165 13.354 310 312 233 168 190 13.855 340 342 263 198 220 14.756 370 372 293 228 250 15.807 400 402 323 258 280 16.108 440 442 363 298 320 17.259 460 462 383 318 340 17.80


90

40

CC B V

G

200

100

10 BONT

Reflex Level GaugesType BR24-GP11 and BR24-GP12


01 Connections between gauge and valves are made– for BR24-GP11, by end tubes and stuffing boxes– for BR24-GP12, by NPT screwed nipples. Minimum CC

distance, shown on table is referred to 3/4” NPT connec-tions. With 1/2” NPT connections CC becomes 30 mmshorter.













1 235 237 158 93 115 12.852 260 262 183 118 140 13.453 285 287 208 143 165 14.554 310 312 233 168 190 15.155 340 342 263 198 220 16.256 370 372 293 228 250 17.357 400 402 323 258 280 17.958 440 442 363 298 320 19.209 460 462 383 318 340 20.15


100

200

G

VBCC

40

90

BONT®

BONT®

11BONT


CC min B V G kg

1 255 165 93 115 24.22 280 190 118 140 35.03 305 215 143 165 25.94 330 240 168 190 26.95 360 270 198 220 28.16 390 300 228 250 29.57 420 330 258 280 30.88 460 370 298 320 32.29 480 390 318 340 33.1


Fig. 856Type BR28-G41

01 Instead of the set of valves G41, the set of valves GP12 canbe used. In this case the level gauge is named BR28-GP12.Connections between gauge and valves are made by NPTscrewed nipples.Minimum C. to C. distance for BR28-GP12 is 61 mm shorterthan for BR28-G41, and its weight is approx. 4 kg less.

02 According to the right of left position of the stop valves handleof the gauge body, the level gauges are named right-handedof left-handed. Fig. 856 shows a left-handed level gauges.


04 Flanges are finished to customer prescriptions. Please state:– Standard – Size– Pressure class – FinishingThe inside passage through the gauge is 12,5 mm.

050Instead of flanges, connections can be delivered with threadedends.It is standard 3/4” NPT union.





10 For level gauges type BR28-G42, BR28-GS41, BR28-GS42,see page 13.

Reflex Level Gaugestype BR28-G41

20

G

VBCC

100

90

160

12 BONT



01 Type BR25-GP12 level gauge is LARGE CHAMBERED. Thegauge body is machined from a tube having thick wall andinternal B of about 40 mm. Large chamber level gaugesshould be used where the medium boils or surges.

02 Connections between gauge and valves are made by NPTscrewed nipples.

03 According to the position of the shut-off valves compared withthe gauge body, the level gauge is named “right-handed” or“left-handed”. Fig. 841 shows a left-handed gauge.Each level gauge can be assembled right-handed or left-handed.

04 When large chamber body is required with butt-welding endcaps, length of body (B) and minimum C. to C. (CC min)have to be increased of 40 mm.


06 Flanges are finished to customer prescriptions. Please state:– Standard – Size– Finishing – Pressure classThe inside passage through the gauge is 40 mm.








CC min B V G kg

1 241 160 93 115 14.42 266 185 118 140 15.53 291 210 143 165 16.64 316 235 168 190 18.65 346 265 198 220 19.06 376 295 228 250 20.37 406 325 258 280 22.88 446 365 298 320 23.39 466 385 318 340 24.2


BONT®

100

200

GVBCC

40

90

Reflex Level Gaugeswith Set of Valves type G41, G42, GS41, GS42

13BONT

BONT®

1 93 158 248 2982 118 183 273 3233 143 208 298 3484 168 233 323 3735 198 263 353 4036 228 293 383 4337 258 323 413 4638 298 363 453 5039 318 383 473 523

2 x 4 373 438 528 5782 x 5 433 498 588 6382 x 6 493 558 648 6982 x 7 553 618 708 7582 x 8 633 698 788 8382 x 9 673 738 828 8783 x 6 758 823 913 9633 x 7 848 913 1003 10533 x 8 968 1033 1123 11733 x 9 1028 1093 1183 12334 x 7 1143 1208 1298 13484 x 8 1303 1368 1458 15084 x 9 1383 1448 1538 15885 x 7 1438 1503 1593 16435 x 8 1638 1703 1793 18435 x 9 1738 1803 1893 19436 x 8 1973 2038 2128 21786 x 9 2093 2158 2248 22987 x 9 2448 2513 2603 2653

01 In the preceding pages we have described our reflex gaugescomplete with set of valves type GP11 and GP12.The same gauge bodies can be completed with:- Set of valves type G41 and G42 which are OFFSET

see Fig. 714 and 715.- Set of valves type GS41 and GS42 which are STRAIGHT

see Fig. 850 and 851.These sets are described in detail on pages. 32 e 33.

02 In the table of this page, for each size (single or combined)are given:V: visible length.B: length of body.CC4: minimum vessel Centre to Centre distance, when the

connection between Set and Body is made byscrewed nipples, Fig. 714 and 850.In this case the body cannot be dismantled from thevalves while operating and therefore eventual change ofa glass must be carried out on place.

CC5: minimum vessel Centre to Centre distance, when theconnection between Set and Body is made by uniontailpipe and union nut, Fig. 715 and 851.In this case the body can be dismantled from the clo-sed valves while operating and therefore eventualchange of a glass can be carried out where moreconvenient.

The values shown in the table are valid only for BONTgauges type: BR23 - BR24.

03 For BONT gauges type BR25 - BR28 and in general forbodies having different length use formula:- for connection by screwed nipples:

CC4 min = Length of body B + 90 mm(exceptionally: CC4 min = B+76 mm)

- for connection by union tailpipe and union nut:CC5 min = Length of body B + 140 mm.

04 As usual the tag indicating the type of the level gauge con-sists of two parts that define:- the type of the level gauge body

hyphen- the type of the set of valves (see also page. 32)

05 Optionals on page 29, 38, 39.

Fig. 714 Fig. 715G42 G42offset offset

Fig. 850 Fig. 851GS42 GS42straight straight

Visible Length Minimum C. to C.length of body (see note 2)

SizeV B CC4 CC5

Fig. 714 and 850 Fig. 715 and 851

GVB

CC4

20

G V B

CC5

20

GVB

CC4

G V B

CC5

14 BONT


Fig. 857 Type BR13-G51

1 Connections between gauge and valves are made by flanges.Gauge body cannot be rotated on its axis. Other connectionson request.

2 According to the right or left position of the handwheel of thestop valves on the gauge body, the level gauges are namedright-handed or left-handed fig. 857 shows a right-handedlevel gauge.

3 When ordering a level gauge please state:- Centre to centre distance between connections (CC)- Standard. Size and Finishing of connections- Whether right-handed or left-handed.

4 Flanges are finished to customer prescriptions. Please state:– Standard – Size– Pressure class – FinishingThe inside passage through the gauge is at least 12,5 mm.

5 Instead of flanges, connections can be delivered with threadedends or with weld ends.

6 BR13 gauges are fitted with reflex glasses type A-BR13 (seepage 40), that ARE NOT COMPRESSED by the tighteningscrew. Joint Dimensions and Maintenance Instructions onrequest.




Size C. to C. Visible Length. Weightdistance length of glass

CC min V G kg

3 330 142 165 754 355 167 190 785 385 197 220 816 415 227 250 857 445 257 280 888 485 297 320 929 505 317 340 94


G

160 150

CC V

210

118

BONT®

1 These gauge bodies are suitable for welding directly on thevessel. Therefore, no valves can be fitted between vessel andgauge, and incase of glass breakage, the fluid flowing from thevessel cannot be stopped.

2 It is necessary to control the suitability of the vessel wall, onwhich the gauge body is to be welded as this must not beexcessively weakened by the holes or communicating windowwith the gauge. Steel plates to strengthen the vessel wallshould be used whenever this is possible.

3 During the welding operation, take care not to expose thegauge body for long time to high temperatures, as this mightdamage the flatness of the glass sealing surface.

4 For BR26 the connecting lip is provied to facilitate the weldingoperation.

Reflex Level GaugesWeld - on Bodies, type BR26 and BR27

15BONT

BONT®

Fig. 717 Type BR26 Fig. 821 Type BR27

Size Length. Visible Length. Weightof body length of glass BR26 BR27

B V G kg kg

1 128 93 115 4.8 3.62 153 118 140 5.7 4.33 178 143 165 6.6 5.04 203 168 190 7.5 5.75 233 198 220 8.6 6.66 263 228 250 9.8 7.57 293 258 280 10.9 8.38 333 298 320 12.4 9.49 353 318 340 13.1 10.0

5 When enquiring or ordering BR27 please state the externalradius (R) of the vessel on which the gauge must be welded.

6 For visible lengths over 318 mm two or more single gaugebodies will have to be welded on the vessel. In this case it isadvisable to fit the gauge bodies not along the same verticalline, but offset.

7 BR26 and BR27 are fitted with reflex glasses type B (seepage 40).


9 Applicable optionals and bolting torques on pages 38, 39.

30° 7

15 20

BVG

R

BVG

16 BONT

Tubular glass Level Gaugestype BTV-GP11

Fig. 842 Type BTV-GP11 Fig. 720 Fig. 721

1 Type BTV-GP11 level gauges have as transparent part a glasstube of 16 mm outside diameter. The limitation of the opera-ting conditions is due to the glass tube, while the valves typeGP11 are suitable for higher pressure and temperature.

2 As the glass tubes are usually found on sale up to a maxi-mum standard length of about 2000 mm, when the centre tocentre distance is longer than this size, the installation of se-veral, cascade disposed level gauges or the application of anintermediate support with stuffing-boxes are necessary. In thelatter case the length of each glass tube will be half the centreto centre distance minus 17 mm.

3 To protect the glass tube against shocks we supply on request– U shaped metallic protector (Fig. 720) to be fixed to the

stuffing box gland and/or– acrylic resin tube protector (Fig. 721) sealed by O-Rings to

the stuffing box gland.





08 BTV-GP11 gauges are fitted with glass tubes having 16 mmoutside diameter and length equal to the centre to centre di-stance minus 21 mm.


10 Applicable optionals on pages 29 and 41.

Dimensions:

Max C. to C. CC max = 2000 mmGlass tube length G = CC –28 mmVisible length V = CC –110 mmWeight nearly kg 7,0

BONT®

VCC

90

40

100

200

Transparent Level Gaugestype BT23-GP11 and BT23-GP12

17BONT

BONT®

Fig. 843 Type BT23-GP11

01 Connections between gauge and valves are made– for BT23-GP11, by end tubes and stuffing boxes– for BT23-GP12, by NPT screwed nipples. Minimum CC

distance, shown on table is referred to 3/4” NPT connec-t ions. For 1/2” NPT connections CC becomes 30 mmshorter.




05 Flanges are finished to customer prescriptions. Please state:– Standard – Size– Finishing – Pressure classThe inside passage through the gauge is 10 mm.


7 BT23 gauges are fitted with transparent glasses type B (seepage 40).




11 For level gauges type BT23-G41, BT23-G42, BT23-GS41,BT23-GS42, see page 22.

1 235 237 158 93 115 10.902 260 262 183 118 140 11.503 285 287 208 143 165 12.304 310 312 233 168 190 12.905 340 342 263 198 220 13.906 370 372 293 228 250 14.657 400 402 323 258 280 15.608 440 442 363 298 320 16.709 460 462 383 318 340 17.40


Size C. to C. distance Length Visible Length WeightBT23-GP11 BT23-GP12 of body length of glass


100

200

GVBCC

40

90

18 BONT



01 Connections between gauge and valves are made– for BT24-GP11, by end tubes and stuffing boxes– for BT24-GP12, by NPT screwed nipples. Minimum CC

distance, shown on table is referred to 3/4” NPT connec-t ions. For 1/2” NPT connections CC becomes 30 mmshorter.











1 235 237 158 93 115 12.102 260 262 183 118 140 13.103 285 287 208 143 165 13.904 310 312 233 168 190 14.955 340 342 263 198 220 16.156 370 372 293 228 250 17.257 400 402 323 258 280 18.458 440 442 363 298 320 19.809 460 462 383 318 340 21.00




BONT®

100

200

GVBCC

40

90

Transparent Level Gaugestype BT25-GP12

19BONT

BONT®


01 Type BT25-GP12 level gauge is LARGE CHAMBERED. Thegauge body is machined from a tube having thick wall andinternal B of about 40 mm. Large chamber level gaugesshould be used where the medium boils or surges.


03 According to the position of the shut-off valves compared withthe gauge body, the level gauge is named “right-handed” or“left-handed”. Fig. 845 shows a left-handed gauge.Each level gauge can be assembled right-handed or left-handed.

04 When large chamber body is required with butt-welding endcaps, length of body (B) and minimum C. to C. (CC min)have to be increased of 40 mm..









Size C. to C. Length Visible Length Weightdistance of body Length of glass

CC min B V G kg

1 241 160 93 115 16.92 266 185 118 140 18.43 291 210 143 165 19.94 316 235 168 190 21.35 346 265 198 220 23.16 376 295 228 250 24.97 406 325 258 280 26.68 446 365 298 320 29.09 466 385 318 340 30.1


200

100

90

CC B VG

40

20 BONT



01 Connections between gauge and valves are made– for BT28-GP11, by end tubes and stuffing boxes– for BT28-GP12, by NPT screwed nipples











12 The BT28 gauge body can be fitted with set of valves G42:this level gauge is called type BT28-G42 and is suitable forwater steam up to 50 bar and 263 °C.

1 272 246 165 93 115 17.12 297 271 190 118 140 18.83 322 296 215 143 165 20.54 347 321 240 168 190 22.05 377 351 270 198 220 24.16 407 381 300 228 250 26.37 437 411 330 258 280 28.38 477 451 370 298 320 31.09 497 471 390 318 340 32.3




BONT®

90

40

CC B V G

200

100

Transparent Level Gaugestype BT29-G41

21BONT

BONT®

Fig. 868 Type BT29-G41


02 According to the position of the shut-off valves compared withthe gauge body, the level gauge is named “right-handed” or“left-handed”. Fig. 868 shows a left-handed gauge.








10 For level gauges type BT29-G42, BT29-GS41, BT29-GS42,see page 22.


CC min B V G kg

1 255 165 93 115 17.42 280 190 118 140 19.13 305 215 143 165 20.84 330 240 168 190 22.35 360 270 198 220 24.46 390 300 228 250 26.67 420 330 258 280 28.68 460 370 298 320 31.39 480 390 318 340 32.6


G

90

CC B V

100 20

160

22 BONT

Transparent Level Gaugeswith Set of Valves type G41, G42, GS41, GS42

1 93 158 248 2982 118 183 273 3233 143 208 298 3484 168 233 323 3735 198 263 353 4036 228 293 383 4337 258 323 413 4638 298 363 453 5039 318 383 473 523


Visible Length C. to C. minimum distancelength of body (remark 2)

SizeV B CC4 CC5

Fig. 727 and 852 Fig. 728 and 853

01 In the preceding pages we have described our trasparentgauges complete with set of valves type GP11 and GP12.

The same gauge bodies can be completed with:- Set of valves type G41 and G42 which are OFFSET

see Fig. 727 and 728.- Set of valves type GS41 and GS42 which are STRAIGHT

see Fig. 852 and 853.These sets are detailed on pages. 32 e 33.

02 In the table of this page, for each size (single or combined)are given:V: visible length.B: length of body.CC4: minimum vessel Centre to Centre distance, when the

connection between Set and Body is made byscrewed nipples, Fig. 727 and 852.In this case the body cannot be dismantled from thevalves while operating and therefore eventual change ofa glass must be carried out on place.

CC5: minimum vessel Centre to Centre distance, when theconnection between Set and Body is made by uniontailpipe and union nut, Fig. 728 and 853.In this case the body can be dismantled from the clo-sed valves while operating and therefore eventualchange of a glass can be carried out where moreconvenient.

The values shown in the table are val id only for BONTgauges type: BT23 - BT24.

03 For BONT gauges type BT25 - BT28 - BT29 and in generalfor bodies having different length use formula:- for connection by screwed nipples:

CC4 min = Length of body B + 90 mm(exceptionally: CC4 min = B+76 mm)

- for connection by union tailpipe and union nut:CC5 min = Length of body B + 140 mm.

04 As usual the tag indicating the type of the level gauge con-sists of two parts that define:- the type of the level gauge body

hyphen- the type of the set of valves (see also page. 32)

05 Optionals on page 29, 38 and 39.

Fig. 727 offset Fig. 728 offsetG41 e G42 G41 e G42

Fig. 852 straight Fig. 853 straightGS41 e GS42 GS41 e GS42

BONT®

GVB

CC4

20

G V B

CC5

20

GVB

CC4

G V B

CC5


23BONT

BONT®

1 Connections between gauge and valves are made by flangesand bolts.Provided valves are closed, gauge body can be easily rotatedon its axis even with boiler under steam in order to adjust easyreading from control floor.

2 According to the right or left position of the stop valves handleon the gauge body, the level gauges are named right-handedor left-handed. Fig. 858 shows a right-handed level gauge.Usually two level gauges (1 right and 1 left) are installed onsteam vessels.

3 According to some Steam Boiler Regualtions, the visible lengthof the level gauges installed on steam boilers must be notshorter than a fixed length. Therefore the suitability of thesmaller sizes must be checked.

04 For visible length over 315 mm we manufacture combinedlevel gauges having two or more gauge bodies on commoncentre piece. Side gauge for by-passing blind distance is recommended (see Fig. 820).


06 Flanges are finished to customer prescriptions. Please state:– Standard – Size– Pressure class – FinishingThe inside passage through the gauge is at least 12.5 mm.

070Instead of flanges, connections can be delivered with weldingends (Socket welding or Butt welding). Please state connec-ting dimensions, size and Standard.






CC min B V G kg

1 337 175 093 115 312 362 200 118 140 333 387 225 143 165 354 412 250 168 190 375 442 280 198 220 396 472 310 228 250 417 502 340 258 280 438 542 380 298 320 459 562 400 318 340 47

G

160-19050

CC B V

210

120


24 BONT


1 Connections between gauge and valves are made by flangesand bolts.Provided valves are closed, gauge body can be easily rotatedon its axis even with boiler under steam in order to adjust easyreading from control floor.

2 According to the right or left position of the stop valves handleon the gauge body, the level gauges are named right-handedor left-handed. Fig. 859 shows a right-handed level gauge.Usually two level gauges (1 right and 1 left) are installed onsteam vessels.

3 According to some Steam Boiler Regualtions, the visible lengthof the level gauges installed on steam boilers must be notshorter than a fixed length. Therefore the suitability of thesmaller sizes must be checked.

04 For visible length over 315 mm we manufacture combinedlevel gauges having two or more gauge bodies on commoncentre piece. Side gauge for by-passing blind distance isrecommended (see Fig. 820).


06 Flanges are finished to customer prescriptions. Please state:– Standard – Size– Pressure class – FinishingThe inside passage through the gauge is at least 12.5 mm.

070Instead of flanges, connections to the vessel can be deliveredwith welding ends (Socket welding or Butt welding). Pleasestate connecting dimensions, size and Standard.






CC min B V G kg

3 387 225 143 165 564 412 250 168 190 625 442 280 198 220 676 472 310 228 250 737 502 340 258 280 788 542 380 298 320 839 562 400 318 340 88

G

160 - 190 50

CC B V

210

120

BONT

BT 32 mod.

BONT®


25BONT

26 BONT

Bicolour Level Gaugestype BC23-GP11, BC24-GP11, BC28-GP11, BC32-G52

For the same operating conditions, we produce both tran-sparent and bicolour level gauges, (see Fig. 824 and 825).

Dimensions (Body length, C to C Distance according to thedifferent type of valve sets, etc.), Description and Mainte-nance Instructions of the Bicolour Level Gauges are identicalto those of the corresponding Transparent Level Gauge.

Design and working principleBONTT bicolour level gauges are made of:– 1 metallic centre piece containing steam and water of which

level is to be measured;– 1 or more flat transparent glasses (long or circular) on the front

face of the gauges;– an equal number of identical glasses on the back face of the

gauge;– 1 or more front covers and an equal number of back covers

holding the glass assemblies against the centre piece;– 1 illuminator case containing suitable lamps and two coloured

glass strips (normally one green and one red);– 1 set of shut-off valves for connection to boiler or tank.The bicolour level gauge has a trapezoidal body and conse-quently the front and the back glasses are non-parallel.They form a small angle. This special assembly and the differentindex of refraction of water and steam allow that the red and thegreen light of the illuminator entering the gauge passes throughthe gauge itself and is seen by the observer as follows:– RED in correspondance of STEAM– GREEN in correspondance of WATER.

ApplicationBicolour level gauges are manufactured by our Company sincemore than 30 years. At the beginning only port-hole level gaugeswere produced (that is with small circular glasses) suitable forvery high water/steam pressure, ut to 225 bar at 374 °C (seeBONTT level gauges type BC1-G55). For these severe conditionsthe small circular glasses are absolutely necessary and cannot besubstituted by other types of glasses.In the recent year bicolour gauges have been very muchappreciated because of the brillant and sure reading they giveand therefore they are more and more requested also for low andmedium water/steam pressure, for which long glasses can safelybe used.In case of combined level gauges, with the bicolour reading it isnot necessary to use side bodies for the uninterrupted visiblelength, allowing a simplification of the instrument.

BC23-GP11 BT23-GP1112 187 Water steam

Fig. 843


Fig. 844


Fig. 846

BC32-G52- BT32-G52125 326 Water steam

Fig. 859

Max. OperatingLevel Gauge FluidContidions

Bicolour Transparent Pressure Temperaturebar °C

Fig. 824 Type BC23 - BC24 - BC28 Fig. 825 Type BC32

BONT®

BONT

BC 32

Bicolour Level Gaugestype BC1-G55

27BONT

BONT®

1 According to the right or left position of the handwheel of thestop valves on the gauge body, the level gauges are namedright-handed or left-handed. Fig. 860 shows a left-handed levelgauge. Usually two level gauges (1 right and 1 left) are installedon steam vessel.

2 This level gauge consists of one gauge type BC1, and one setof valves type G55. It MUST be installed with the gauge body invertical position.G55 set is connected to a vertical pipe, which links upper andbottom gauge parts. It avoid condensate to flow through gaugebody therefore grant ing bet ter v is ib i l i ty and longer l i feof glasses.Gauge body is connected to pipe/valve assembly through twoflanges and can be easily removed for inspection and service.

3 This gauge consists of a central body type BC1 and a certainnumber of covers attached to the front and the back of thebody: the covers contain small circular glasses.Central body is usually manufactured of stainless steel for alonger life of the whole instrument.The illuminator is fitted with a bicolour filter: half of it is red andhalf green. The illumination of the gauge is based on thedifference of refractive indexes of steam and water. The lightsource projects its rays through the adiacent coloured filter andin the steam and water spaces these coloured light rays arerefracted to a different degree depending upon the refractiveindex of the medium. This permits only one colour of light to

Fig. 860 Type BC1-G55

emerge from each medium, the other being absorbed in thewalls of the gauge.In particular the circular glasses appear:- RED in correspondance of STEAM- GREEN in correspondance of WATERThe level can be:- read by observer standing directly IN FRONT of the level

gauge, at the same height of body,- transmitted to the control station by means of a simple

periscopic arrangement with mirrors. The mirrors (both topand bottom) are adjustable to assist alignment,

- observed by means of close circuit television,- trasmitted to the control station by means of fibre optic

remote v iewing device, by means of our Red CherrySystem. Ask for peculiar bulletin.

Needs of each plant should be known before stating supplyingdetails.

04 The standard illuminator is explosion-proof and consists of astainless steel box containing a certain number of bulbs inagreement with the number of port holes and suitble for 12 V.The illuminator is slotted so as to fit into the level gaugecentre piece. The red and green coloured filters are placed infront of the bulbs. The red filter must be placed in corre-spondence of the narrow side of the gauge body; the greenfilter or the wide side. In this way the view of red steam andgreen water will be produced.Should a bulb fail i can be easily replaced by opening the backside of the illuminator. For right lightening replace bulbs of theidentical type use by first delivery.

05 For visible lengths longer or shorter than those listed on thetable, we manufacture BC1 gauges with adequate number ofport holes on one single centre piece.

06 Centre to centre distance (CC) shown on table are referred tobodies with holes having standard pitch of 73 mm.

07 When ordering a level gauge please state:- Centre to centre distance between connections (CC)- Standard, Size and Finishing of connections- Whether right-handed or left-handed.

08 Flanges are finished to customer presciptions. Please state:- Standard - Size- Pressure class - FinishingThe inside passage through the gauge is at least 12,5 mm.

09 Instead of flanges, connections can be delivered with weldingends (Socket welding or Butt welding). Please state con-necting dimensions, size and Standard.

10 BC1 gauges are fitted with transparent glass discs(B 36,6 x 12,7 mm).Dimensions of joints and mica and Maintenance Instructionson request.


12 Applicable optionals and bolting torques on pages. 29 and 39.


Size Number of C. to C. Length Visible Weightport-holes distance of body length

CC min B V kg

05 05 472 372 311 09406 06 545 445 384 10007 07 618 518 457 10708 08 691 591 530 11309 09 764 664 603 11910 10 837 737 676 12611 11 910 810 749 132

160-190

175

CC V

210

B

335

385

28 BONT

Transparent Level GaugesWeld - on Bodies, type BT26 and BT27

Fig. 734 Type BT26 Fig. 822 Type BT27

Size Length. Visible Length. Weightof body length of glass BT26 BT27

B V G kg kg

1 128 93 115 4.8 3.62 153 118 140 5.7 4.33 178 143 165 6.6 5.04 203 168 190 7.5 5.75 233 198 220 8.6 6.66 263 228 250 9.8 7.57 293 258 280 10.9 8.38 333 298 320 12.4 9.49 353 318 340 13.1 10.0

1 These gauge bodies are suitable for welding directly on thevessel. Therefore, no valves can be fitted between vessel andgauge, and in case of glass breakage, the fluid flowing from thevessel cannot be stopped.

2 It is necessary to control the suitability of the vessel wall, onwhich the gauge body is to be welded as this must not beexcessively weakened by the holes or communicating windowwith the gauge. Steel plates to strengthen the vessel wallshould be used whenever this is possible.

3 During the welding operation, take care not to expose thegauge body for long time to high temperatures, as this mightdamage the flatness of the glass sealing surface.

4 Fro BT26 the connecting lip is provided to facilitate the weldingoperation.

5 When enquiring or ordering BT27 please state the externalradius (R) of the vessel on which the gauge must be welded.

6 For visible lengths over 318 mm two or more single gaugebodies will have to be welded on the vessel. In this case it isadvisable to fit the gauge bodies not along the same verticalline, but offset.

7 BT26 and BT27 are fitted with transparent glasses type B (seepage 40).


9 Applicable optionals and bolting torques on pages 38, 39.

Level GaugesOptionals for Sets of Valves

29BONT

BONT®

Set Valve Plug Top and Operated by HeatingType Fig. top bottom drain vent drain vent bottom handwheel chain double weighted external internal

ball-check handwheel lever lever

GP11 831 S S S A A A A S NA NA NA A NA

GP12 832 S S S A A S A S NA NA NA A NA

G41 747 S S A A A A S S NA A A A A

G42 748 S S A A A A S S A A A A A

GS41 854 S S A A A A S S NA A A A NA

GS42 855 S S A A A A S S A A A A NA

G51 861 S S S A NR NR A S A NA NA A NA



Fig. 865

Keys and Remarks to Fig. 865

S – Standard EquipmentA – ApplicableNA – Not applicableNR – Possible, but not recommended

1 – We mean by Set the assembly of two valves (1 top and 1bottom) for the connection of the gauge body to the vessel.The set stops fluid between vessel and level gauge in caseof servicing.

2 – This bulletin shows only our level gauges of metal; the setsfitted to the level gauges include the following patterns:– type GP11 and GP12, top and bottom: piston valves;

(see pages 30 and 31)– type G41 and G42, metallic seating valves, with stainless

steel screwed-in seat and stainless steel disk (see pages32 and 33). “Offset”

– type GS41 and GS42, metall ic seating valves, withstainless steel screwed-in seat and stainless steel disk(see pages 32 and 33). “Straight”

– type G51, G52, G55 , metal l ic seat ing valves, wi thStellite faced trim (see pages 34 and 35).

3 – Each set is usually supplied with or without some optionalsaccording to its original design and its main application.

4 – EXTERNAL HEATING has electrical or steam tracing, in-stalled on job site. By INTERNAL HEATING gauge body isinside traced for heating fluid.

5 – All sets can be supplied with INTERMEDIATE SUPPORTfitted on the vessel in the middle between top and bottomvalve in case of very large C. to C. distance. Intermediatesupport usually clamps only the gauge bodies and is not inconnection with the vessel inside.

6 – Optionals for gauge bodies on pages 38 and 39.

30 BONT

Gauge Valves Offset Valves type GP11 and GP12suitable for ANSI 300 and PN 400 (type GP11)suitable for ANSI 600 and PN 100 (type GP12)

Fig. 833

Material Body and Trim Remarks ApplicationSchedule wetted parts

52 Forged carbon steel ASTM A 105 Stainless steel Exclusion of copper, silver and their alloys. General purpose

63 Forged stainless steel AISI 316 Stainless steel AISI 316 External not wetted parts Corrosive fluids and/or fluids atof S.S. AISI 304 or 303. temperature lower than –29 °C

64 Forged stainless steel AISI 316 Stainless steel AISI 316 External not wetted parts of carbon steel. Corrosive fluidsExclusion of copper, silver and their alloys.

General informationThese sets of valves consist usually of:– 2 shut-off valves (1 top and 1 bottom)– 1 drain valve.

The advantages of this design are:– excellent performance of Piston Valves, qualified according to:

– API 6 FA and BS 6775: Fire Safe– TA Luft: German Clean Air, TÜV Mannheim– Druckbehälterverordnung § 22: for railway and road tankers

down to –40°C, TÜV München– easy servicing– easy dismantling of the gauge body, to facilitate repla-

cement of the glass.

These sets are suitable for:– type GP11 (connection to gauge body by stuffing box) Fig. 831

ANSI class 300 and PN 40– type GP12 (connection to gauge body by screwed nipples)

Fig. 832:ANSI class 600 and PN 1000

Maximum service temperature: 425°C (797°F).

According to the position of the shut-off valves compared with thegauge body, the Set of valves (and therefore the level gauge) isnamed “right-handed” or “left-handed”.Fig. 831 shows a left-handed gauge. Each level gauge can be as-sembled right-handed or left-handed

Connection to the vesselCan be:– flanged to customer requirements.

Please state: – Standard – Size– Pressure class – Finishing

The flanges are integral with the body.Different sizes and finishings of flanges can be obtained accor-ding to the most used international Standards (ANSI, AFNOR,BS, DIN, GOST, UNI, etc.).

– screwed: – 3/4” NPT Male Plain Union– 3/4” NPT Male Spherical Union– 3/4” NPT Male Integral

– welded: 3/4” Socket Welding– other connections on request.

Connection to the gauge bodyCan be:– type GP11: connection by stuffing boxes and end tubes. (Fig. 831).– type GP12: connection by NPT screwed nipples (Fig. 832).In both choices the connection is made by means of head-pieces(item 41 or 51) and allows easy dismantling of the gauges forservicing and easy rotating on its axis for the best reading, providedvalves are closed even with vessel under pressure.

Centre to Centre distanceWhen these sets of valves are chosen for the level gauge, the valueof the minimum vessel C. to C. distance is given from the formula:

– type GP11:Minimum C. to C. = Length of body + 107 mm

(CC min = B + 107 mm)

– type GP12:Minimum C. to C. = Length of body + 81 mm

(CC min = B + 81 mm)

Fig. 831 Type GP11

Fig. 832 Type GP12

BONT®

6070

40

90

CC

100

180

200

6070

40

90

CC

100

180

200

31BONT

Item Part Part Material for Material Schedule52 63 64

Upper and Lower Valve01 Body ASTMA105 ASTM A182 F316 ASTM A182 F31602.1 Lower Valve Ring Graphite St. St. Graphite St. St. Graphite St. St.l02.2 Upper Valve Ring Graphite St. St. Graphite St. St. Graphite St. St.03 Lantern Bush Carbon Steel ASTM A479 T316 ASTM A479 T31604 Piston ASTM A479 T316 ASTM A479 T316 ASTM A479 T31606 Spindle ASTM A479 T410 ASTM A479 T304 ASTM A479 T41007 Handwheel Alluminium Alluminium Alluminium08 Handwheel Nut Carbon Steel Carbon Steel Carbon Steel09 Bonnet ASTM A105 ASTM A182 F316 ASTM A10510 Stud Bolt and Nut A193 B7 - A194 2H A193 B8 - A194 G8 A193 B7 - A194 2H11 Washer Carbon Steel Carbon Steel Carbon Steel12 Stud Bolt and Nut A193 B7 - A194 2H A193 B8 - A194 G8 A193 B7 - A194 2H14 Gasket Asbestosfree Asbestosfree Asbestosfree

Drain Valve21 Body ASTM A105 ASTM A182 F316 ASTM A182 F31622 Valve Ring Graphite St. St. Graphite St. St. Graphite St. St.23 Bonnet ASTM A105 ASTM A182 F316 ASTM A10524 Needle ASTM A479 T410 ASTM A479 T316 ASTM A479 T31625 Screw A193 B7 A193 B8 A193 B727 Handwheel Alluminium Alluminium Alluminium28 Handwheel Nut Carbon Steel Carbon Steel Carbon Steel

41 Head GP11 ASTM A105 ASTM A479 T316 ASTM A479 T31642 Packing Ring Graphite St. St. Graphite St. St. Graphite St. St.43 Stuffing Box Ring Carbon Steel. ASTM A479 T316 ASTM A479 T31644 Stuffing Box Nut Carbon Steel ASTM A479 T316 Acc. Carb.

51 Head GP12 ASTM A105 ASTM A479 T316 ASTM A479 T31654 NPT Vent Plug Carbon Steel ASTM A479 T316 ASTM A479 T316

Optionals– Vent Plug on the upper head-piece (standard for GP12)– Vent Valve on the upper head-piece– Automatic Safety Ball-Check, in the upper and lower valve– External tracing for heating or cooling, by electrical wire or pipe

(to be made on field)– Intermediate support not connected with the vessel, for very long

C. to C. distance.

Material SchedulesStandard Material Schedules as per Fig. 833.Other Material Schedules available on request.Parts material is listed on Fig. 866.

Request or OrderPlease state:– type of set Code GP11 or GP12– right-handed or left-handed– connections to the vessel to be detailed– eventual optionals– Material Schedule Fig. 833

ServiceBefore the valves are put in service:– shut off the upper and lower valve and lightly follow up the bon-

net Nuts (10)– open the drain valve and lightly follow up the bonnet Screws (25)– follow up the Gaskets (14) by the Nuts (12).

Spare partsOne complete set of sealing elements for 1 level gauge consists of:– 5 Valve Rings (item 2.1 - 2.2. - 22) B 10 x B 18 x 6– 2 Gaskets (item 14) B 20 x B 10,5 x 1– 2 Packing Rings (item 42) B 16 x B 23,5 x 5, for GP11 only.

Fig. 834 GP11 GP12

Fig. 866

32 BONT

Gauge Valves Set of Valves type G41, G42, GS41, GS42suitable for ANSI 1500 and PN 250

General informationThese sets of valves are designed and manufactured expresslyfor use with level gauges and pressure gauges up to ANSI 1500and PN 250. For use with water steam, we recommend the typeGS42 and G42, with outside screw and yoke.These valves have bol ted bonnet and metal l ic t r im wi threnewable seat.The valves are available:OFFSET with Inside Screw (Fig. 747) . . . . . . . . . . .Code G41

with Outside Screw and Yoke(Fig. 748) .Code G42STRAIGHTwith Inside Screw (Fig. 854) . . . . . . . . . .Code GS41

with Outside Screw and Yoke (Fig. 855) Code GS42They are both suitable for ANSI 1500 and PN 250.

- The Body is of drop forged steel.- The Bonnet is of drop forged steel and of the same material as

body. It is bolted to the body by means of four bolts with nut.The advantages of this design are quite obvious, with respectto a bonnet screwed into the body or to a bonnet connected tothe body by means of studs.

- The Disk is integral on the Stem, is made of stainless steelAISI 316 and is backseating against the bonnet when the valveis full open, for easy repacking under pressure..

- The Seat is of stainless steel AISI 316 (Monel or specialmaterial on request) and is easy renewable, being seal screwed into the body.

- One Safety Ball-Check of stainless steel AISI 316 (specialmaterial on request) is fitted to both valves as standard, forsafety in the event of glass breakage. The safety ball isremoved from its seat during the closing operation of the valveby means of the Stem extremity.

- The Packing is made of an adequate number of preformedrings of an approved high pressure - temperature quality.Special material on request.

- The Name Plate bears all prescribed indications and is fixed oneach valve.

- For Operating three solutions are available:- Handwheel for plain-closing stem . . . . . . . . . . . . . . . .Code 1- Weighted lever for quick-closing stem . . . . . . . . . . . .Code 2- Double-ended lever for quick-closing stem . . . . . . . . .Code 3

Connections to the vasselCan be:- flanged; - integral flange up to 125 mm o.D. (standard)

- weld-on flange for major o.D.Please state:- Standard - Pressure class- Size - Finishing

- screwed: - 3/4” NPT male union (standard)- 3/4” NPT male union spherical,- 3/4” NPT male integral.

- welded : 3/4” socket welding- other connections on request.

Connections to the gauge bodyCan be:- screwed 1/2” NPT female for nipple (standard) . . . . . . .Code 4- screwed 3/4” NPT female for nipple,- socket welding 1/2” or 3/4”- with union tailpipe 1/2” NPT male and union nut

(standard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Code 5- stuffing box for glass tube 16 mm. o.D. . . . . . . . . . . . . .Code 6

Length of glass tube must be 21 mm. shorterthan the Centre to Centre distance

- other connections on request.

Centre to Centre distanceWhen these sets of valves are chosen for the level gauge, thevalue of the minimum vessel C. to C. distance is given from theformula:- for the Set Code 4 (screwed nipples 1/2” NPT):

Minimum C. to C. = Length of body + 92 mm(CC min = B + 92 mm)

(exceptionnally: CC min = B + 76 mm).- for the Set Code 5 (tailpipe 1/2” NPT and union nut):

Minimum C. to C. = Length of body + 124 mm(CC min = B + 124 mm).

Connection to drain and ventCan be:- screwed 1/2” NPT female (standard) . . . . . . . . . . . . . . .Code 7- screwed 3/4” NPT female,- other connections on request.

Optionals (see also page 29)- For Heating or Cooling the valves are available with internal

tube (only G41 and G42).- For Very Low Temperature the inside screw valves (type G41

and GS41) are available with prolonged stem.- For very large C. to C. distance an intermediate support (not

communicating with the vessel) is available.

Material SchedulesMaterial Schedules currently manufactured on Fig. 749.Other Material Schedules with other materials on request.Part material is listed on Fig. 750.

Request or OrderPlease state- OFFSET, inside screw . . . . . . . . . . . . . . . . . . . . . . .Code G41- OFFSET, outside screw . . . . . . . . . . . . . . . . . . . . . . Code G42- STRAIGHT, inside screw . . . . . . . . . . . . . . . . . . . . Code GS41- STRAIGHT, outside screw . . . . . . . . . . . . . . . . . . Code GS42- Operating . . . . . . . . . . . . . . . . . . . . . . . . . . . .Code 1 or 2 or 3- Connections to the vessel . . . . . . . . . . . . . . . . .to be detailed- Connections to gauge body . . . . . . . . . . . . . .Code 4 or 5 or 6- Connections to drain and vent . . . . . . . . . . . . . . . . . . . .Code 7- Material Schedule . . . . . . . . . . . . . . . . . . .Code 52 or 55 or 63- Centre to Centre distance . . . . . . . . . . . . . . . . . . . .to be state

CodeWhen these sets are chosen with our standard variants, the useof our Code is recommendable. For instance:- 1 Set of vales

inside screw OFFSET . . . . . . . . . . . . . . . .Code G41.1.4.7.52operated by handwheel . . . . . . . . . . . . . . . . . . . . . . . . 1.4.7.52connections to gauge body screwed 1/2” NPT female. . . 4.7.52connections to drain and vent 1/2” NPT female. . . . . . . . . 7.52material schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Resulting CODE: . . . . . . . . . . . . . . . . . . . . . . . . G41.1.4.7.52

It is to be stated in detail:- connections to the vessel,- Centre to Centre distance.

MaintenanceThese sets don’t need any special maintenance. We only recom-mend to check from time to time the tightening of Packing gland(45) and of body-bonnet Bolts (5).

Fig. 745 Type G41 and GS41 Fig. 746 Type G42 and GS42

BONT®

33BONT

Fig. 747 Type G41 (offset 20 mm)

Fig. 748 Type G42 (offset 20 mm)

Fig. 854 Type GS41 (straight)

Note: remaining parts identical to Fig. 747

Fig. 855 Type GS42 (straight)

Note: remaining parts identical to Fig. 748

Fig. 749Material Body bonnet and Trim and Remarks ApplicationSchedule wetted parts Ball-check

52 Forged carbon steel Stainless steel Exclusion of cooper General purposeASTM A105 AISI 316 silver and their alloys

55 Forged carbon steel Stainless steel External not wetted Non corrosive fluids at lowASTM A350 LF2 AISI 316 parts of S.S. temperature up to –45,6 °C (–50 °F).

AISI 304 or 303

63 Forged stainless steel Stainless steel External not wetted Corrosive fluids and/orAISI 316 AISI 316 parts of S.S. fluids at temperature lower

AISI 304 or 303 than –45,6 °C (–50 °F)

Fig. 750

Item Part Materials for Material Schedule

52 55 63

01 Body ASTM A105 ASTM A350 LF2 S.S. AISI 31602 Seat S.S. AISI 316 S.S. AISI 316 S.S. AISI 31603 Ball-check S.S. AISI 316 S.S. AISI 316 S.S. AISI 31604 Bonnet joint ring Soft iron S.S. AISI 316 S.S. AISI 31605 Bolt ASTM A193 B7 S.S. AISI 303 S.S. AISI 30306 Nut ASTM A194 2H S.S. AISI 303 S.S. AISI 30307 Bottom ring Carbon steel S.S. AISI 316 S.S. AISI 31608 Packing Preformed rings Preformed rings Preformed rings09.1 Handwheel Carbon steel Carbon steel Carbon steel09.2 Weighted lever Carbon steel Carbon steel Carbon steel09.3 Double-ended lever Carbon steel Carbon steel Carbon steel10 Name plate Stainless steel Stainless steel Stainless steel11 Washer Carbon steel Carbon steel Carbon steel12 Nut ASTM A194 2H S.S. AISI 303 S.S. AISI 30313 Taper plug (on request) Carbon steel S.S. AISI 316 S.S. AISI 31614 Union nut Carbon steel S.S. AISI 303 S.S. AISI 30315 Union tailpipe Carbon steel S.S. AISI 316 S.S. AISI 31616 Joint ring Suitable compressed material

Item Part Materials for Material Schedule

52 55 63

17 Nipple Carbon steel S.S. AISI 316 S.S. AISI 31618 Nut Carbon steel S.S. AISI 303 S.S. AISI 30319 Union tailpipe Carbon steel S.S. AISI 316 S.S. AISI 31620 Joint ring Suitable compressed material

31 Stem S.S. AISI 316 S.S. AISI 316 S.S. AISI 31632 Bonnet ASTM A105 ASTM A350 LF2 S.S. AISI 31633 Bonnet flange ASTM A105 ASTM A350 LF2 S.S. AISI 30434 Gland Carbon steel S.S. AISI 304 S.S. AISI 30435 Gland nut Carbon steel S.S. AISI 304 S.S. AISI 304

41 Stem S.S. AISI 316 S.S. AISI 316 S.S. AISI 31642 Stem bush S.S. AISI 410 S.S. AISI 410 S.S. AISI 41043 Bonnet ASTM A105 ASTM A350 LF2 S.S. AISI 31644 Packing gland Carbon steel S.S. AISI 304 S.S. AISI 30445 Bolt ASTM A193 B7 S.S. AISI 303 S.S. AISI 30346 Nut ASTM A194 2H S.S. AISI 303 S.S. AISI 303

34 BONT

Gauge Valves Set of Valves type G51, G52, G55suitable for ANSI 2500 and PN 400

Fig. 863 Type G55

General informationThese sets of valves consist of metallic seating valves.Each set is generally composed by:- 2 shut-off valves sized 1” (1 top and 1 bottom)- 1 drain valve sized 1/2”.The Set of valves fully comply with the main internationalStandard and specifically with ASME Code Section I, whenapplicable.The shut-off valves are bonnetless type, operated by handwheelwith rising non-rotating stem and stroke indicator.- The Body (1) is forged of carbon steel or stainless steel and is

the only valve part under pressure. Seat is integral of Stellitedeposited with highly specialized and automatic procedure.The Backseat ring (46) is threaded into the body and can beeasily replaced.

- The Yoke (2) is always forged and is standard of carbon steel,has structural functions only and is not under pressure.Threaded outside the body and kept in place by means of onewelding tack that can be easily removed and remade forinspection or maintenance..

- The Disk (3) is of alloy steel whit seating surface Stellite. Whenbackseated, disk is pulled against bonnet with axial (notrotating) movement.

- The Stem (4) is of stainless steel, heat treated. Threads areACME. Being designed rising and non-rotating insures a lowerdriving and closing torque and less wear of packing rings.

- The Yoke Bushing (11) is usually of special aluminium bronzeand is kept in place by two Antifriction Rings (43) and form aLocking Ring (39).

- The Packing includes one Bottom Ring (5), one GraphitePacking (6), one Packing Flange (10), two Swing Bolts (8)turning for easier repacking.

- The Safety Ball-check (80) are in stainless steel AISI 316 andtighten on a seat made of stainless steel AISI 316

Top Valve

Connection to the drumCan be:- flanged- S W- B W

Connection to the gauge bodyCan be:- type G51 (Fig. 861, 857): flanged on the side of the gauge body,- type G52 (Fig. 862, 858, 859): flanged on the axis of the gauge

body,- type G55 (Fig. 863, 860): flanged with the interposition of a

water column,- different connection to customer prescription.

Fig. 867

Bottom Valve

Item Part Part Material for Material Schedule51 64

1 Body ASTM 105 ASTM A182 F316+ Stellite Gr. 6 + Stellite Gr. 6

2 Yoke ASTM A105 ASTM A1053 Disk ASTM A479 T.316 ASTM A479 T.316

4 Stem ASTM A182 F6 ASTM A564 T.6305 Bottom rIng ASTM A479 T.316 ASTM A479 T.3166 Packing Graphite Graphite8 Swing bolt ASTM A193 B7 ASTM A193 B79 Pin Alloy steel Alloy steel

10 Packing flange ASTM A105 ASTM A182 F31611 Yoke bushing ASTM B150 - C62300 ASTM B150 - C6230012 Handwheel Carbon steel Carbon steel14 Disk pad ASTM A182 F6 Stainles steel + treatment15 Handwheel nut Carbon steel Carbon steel15 A Bolt nut ASTM A194 2H ASTM A194 2H20 Name plate Stainless steel Stainless steel23 Antirotation

indicator Carbon steel. + Zinc. Carbon steel. + Zinc.39 Locking ring ASTM A105 ASTM A10542 Retaining ring Alloy steel Alloy steel43 Antifriction washer Carbon steel C70 Carbon steel C7046 Backseat ring ASTM A564 T.630 ASTM A564 T.63048 Gasket Graphite Graphite70 Connecting

ring Stellite Stellite80 Safety ball ASTM A479 T.316 ASTM A479 T.31681 Bottom taper plug

for ball ASTM A105 ASTM A479 T.31682 Top taper plug

for ball ASTM A105 ASTM A479 T.31683 Welded nipple ASTM A105 ASTM A479 T.31684 Connecting flange ASTM A105 ASTM A10585 Lenticular

joint ring ASTM A479 T.316 ASTM A479 T.31686 Joint ring Graphite Graphite

BONT®

84 80 80 84 86 83

BONT®

35BONT

Optionals (see also page 29)Following optionals can be supplied:- Vent valve on top valve,- Safety ball-check on bottom valve, vertical,- Safety ball-check on top valve, horizontal with removal device.

Material Schedules (see Fig. 867)Material Schedules currently manufactured on Fig. 867.Other Material Schedules with other materials on request.

MaintenanceThese sets of valves need no particular maintenance. We wouldsuggest to use good quality packings in the stuffing-box and tofollow up the bolts of the packing gland from time to time.

Fig. 861 Type G51 Top and bottom Valve

84 80 85 84

Fig. 862 Type G52

Top Valve

Bottom Valve

36 BONT

Level GaugesReflex Gauge BodiesDescription and Maintenance Instructions

Service maintenanceBefore putting in service, check the bolting torque as recom-mended on top of this page. Tighten the bolts alternatively,starting from centre of gauge. To avoid glass thermal shocksduring start-up, the gauge temperature must gradually increase inorder to allow both the metallic structure and the glass to reach theoperating temperature. Proceed as follows: close bottom shut-offvalve, completely open drain, partially open top shut-off valve toallow a minimum flow outlet of steam. Mantain flow outlet untilproper temperature is reached, then close drain valve; the conden-sate coming through top valve will fill the gauge column. At this stepcompletely open very slowly bottom shut-off valve, then completelyopen top shut-off valve.In case during operation fluid impurities affect glass, proceed togauge washing as above described

Important noticeMaintenance must be made immediately when:- leakage appears, even if very small. In this case: shut of and cool

down the gauge. Tighten the gauge nuts at the recommendedbolting torque;

- the glass appears opaque or slightly white specially in the steamarea;

- grooves of the reflex glass show sign of corrosion and/or ero-sion and the reading of the level is not clear.

The lack of maintenance and the lack of replacement of the dete-riorated parts can cause the breakage of the glass with all therelevant consequences.

Dismantling- Shut off the valves, let out the pressure and remove the level

gauge body from the valves.

- Loosen the tightening bolts and remove all component pieces.- Clean the sealing and cushion surfaces very carefully, making

sure that they are clear of any remnants of joints.- Smear the threads of the tightening bolts with a thin layer of

graphitized grease;

Reassembling- Fit in a new glass with new joints (never re-use joints which have

already been in service!): remember that the sealing joint must beplaced on the side where the grooves are.

- Reassemble all the components in the right sequence. Tighten thebolts alternatively, starting from centre of gauge.

- Never grip the level gauge body in a vice during the reassembling,but put it on a plane surface.

- Never use adhesive or hermetic mastics. Remember that all surfa-ces must be perfectly clean.

Spare parts- When ordering spare parts please state:

- type and size of the gauge body- item number of the spare part, as shown in the above list- construction material.

- As regards reflex glasses and their joints, please remember that:- each type BR12, BR14 gauge is fitted with 1 reflex glass

type A (section 30x17 mm),- each type BR22, BR23, BR24, BR25, BR28 gauge is fitted with

1 reflex glass type B (section 34x17 mm).

For type BR13, separate instructions on request.

1 Centre piece 8 Gauge body2 Sealing joint 9 Wedge piece3 Reflex glass 10 Thightening bolt4 Cushion joint 11 Bolt with nut5 Cover plate 12 Clamp6 U stud bolt with nuts 13 Angular piece7 O stud bolt with nuts

Bolting torques- Type BR14 35 Nm - Type BR24 50 Nm- Type BR12 60 Nm - Type BR28 50 Nm- Type BR22 30 Nm - Type BR25 40 Nm- Type BR23 50 Nm

Fig. 817 Type BR14

Fig. 762 Type BR24 Fig. 819 Type BR28 Fig. 763 Type BR25

Fig. 816 Type BR12 Fig. 760 Type BR22 Fig. 761 Type BR23

BONT®

BONT®

37BONT

Level GaugesTransparent Gauge BodiesDescription and Maintenance Instructions

Service maintenanceBefore putting in service, check the bolting torque as recom-mended on top of this page. Tighten the bolts alternatively,starting from centre of gauge. To avoid glass thermal shocksduring start-up, the gauge temperature must gradually increase inorder to allow both the metallic structure and the glass to reach theoperating temperature. Proceed as follows: close bottom shut-offvalve, completely open drain, partially open top shut-off valve toallow a minimum flow outlet of steam. Mantain flow outlet untilproper temperature is reached, then close drain valve; the conden-sate coming through top valve will fill the gauge column. At this stepcompletely open very slowly bottom shut-off valve, then completelyopen top shut-off valve.In case during operation fluid impurities affect glass or protectionshield, proceed to gauge washing as above described

Important noticeMaintenance must be made immediately when:- leakage appears, even if very small. In this case: shut of and cool

down the gauge. Tighten the gauge nuts at the recommendedbolting torque;

- the glasses appear opaque or slightly white specially in the steamarea;

- the reading of the level is not clear.The lack of maintenance and the lack of replacement of thedeteriorated parts can cause the breakage of the glasses with all therelevant consequences.

Dismantling- Shut off the valves, let out the pressure and remove the level

gauge body from the valves.

- Loosen and take out the tightening bolts and remove all compo-nent pieces as well.

- Clean the sealing surfaces of the centre piece and the cushion surfaces of the cover plates very carefully, making sure that theyare clear of any remnants of joints.

- Smear the threads with a thin layer of graphitized grease.

Reassembling- Fit in new glasses with new joints (never re-use joints which

have already been in service!). Remember that the glass protec-tion sheet must be in direct contact with the inner side of theglasses (between the glass and the fluid), and that the sealingjoint must be placed on the sealing surface of the centre piece.Reassemble all the other components in the right sequence, and tighten the bolts alternatively, starting from centre of gauge.

- Never grip the level gauge body in a vice during the reassembling,but put it on a plane surface.

- Never use adhesive or hermetic mastics. Remember that all surfa-ces must be perfectly clean.

Spare parts- When ordering spare parts please state:

- type and size of the gauge body- item number of the spare part, as shown in the above list- construction material.

- As regards plate glasses their joints and protection sheets,remember that each level gauge is fitted with 2 plate glassestype B (section 34x17 mm).

For type BC1 (bicolour), separate instructions on request.

1 Centre piece 6 Cover plate2 Sealing joint 7 Bolt with nut3 Glass protection sheet 8 Stud bolt with nut

(where applicable) 9 Stud with nut4 Plate glass 13 Angular Piece5 Cushion joint 14 Belleville Washer

Bolting torques- Type BT23 50 Nm - Type BT29 80 Nm- Type BT24 50 Nm - Type BT33 80 Nm- Type BT25 40 Nm - Type BT32 90 Nm- Type BT28 80 Nm

Fig. 767 Type BT28 & BT29 Fig. 814.1 Type BT33 Fig. 815.1 Type BT32

Fig. 764 Type BT23 Fig. 765 Type BT24 Fig. 766 Type BT25

38 BONT

Level GaugesOptionals for Gauge Bodies

Fig. 826 Illuminator type GSI Fig. 827 Illuminator type EXGSI Fig. 828 Illuminator type EXPIN

Fig. 820 Fig. 773 Remark 7

Fig.776

Fig. 829 Remark 7

Fig. 773 - Non-frosting block for reflex levelgauge.

Fig. 776 - Level gauge with external hea-ting or cooling tube. Reflex (as in figure) ortransparent.

Fig. 820 - Combined level gauge with un-interrupted visible length. Reflex (as infigure) or transparent.

Fig. 826 - Illuminator type GSI, for ligh-tingof the meniscus at water level from lowerposition, not explosion-proof.

Fig. 827 - I l luminator type EXGSI, forlighting of the meniscus at water level fromlower position, explosion-proof.

Fig. 828 - Illuminator type EXPIN, for dif-fused lighting, explosion-proof.

Fig. 829 - Non-frosting block for transpa-rent level gauge, complete with illuminatortype EXPIN.

BONT®

BONT®

39BONT

Level GaugesOptionals for Gauge Bodies - Bolting Torques

Type of glass Optionals

Reflex Transparent Glass Protection Non frosting Heating or Applicable Scales Floats Uninterrup-blocks cooling illuminator ted visible

internal external length

Mica Kel-F Remark 7 internal external Remark No. Remark 9 Remark 9 Fig. 775

BoltingTorque

NmeachBolt

Fig. 777

Typeof

Gauge

BR14 X – – – – – NA NA NA NA NA NA 1 A NA NA 35

BR 12 X – – – – – NA NA NA NA NA NA 1 A NA NA 60

BR22 – X – – – – NA NA NA NA A A 1 A NA A 30

BR23 – X – – – – NA NA V A A A 1 A NA A 50BR24 – X – – – – NA NA V A A A 1 A NA A 50

BR28 – X – – – – NA NA V A A A 1 A NA A 50BR25 – X – – – – NA NA V A A A 1 A NA A 40BR13 – – X – – – NA NA NA A A NA 1 A NA NA (Remark 8)

BR26 – X – – – – NA NA V A A NA 1 A NA NA 40BR27 – X – – – – NA NA V A A NA 1 A NA NA 40

BTV – – – X – – NA NA R NA A NA 1 A A – –

BT23 – – – – X – A A V A A A 4 A A A 50BT24 – – – – X – A A V A A A 4 A A A 50

BT25 – – – – X – A A V A A A 4 A A A 40BT28 – – – – X – A A V A A A 2, 3, 4 A A A 80

BT29 – – – – X – A A V A A A 2, 3, 4 A A A 80BT33 – – – – X – A A V A A A 2, 3, 4 A A A 90

BT32 – – – – X – A A V A A NA 2, 3, 4 A A A 80

BT26 – – – – X – A A V A A NA 1 A NA NA 40BT27 – – – – X – A A V A A NA 1 A NA NA 40

BC23 – – – – X – C NA NA NA NA NA 5 NA NA NA 50BC24 – – – – X – C NA NA NA NA NA 5 NA NA NA 50BC28 – – – – X – C NA NA NA NA NA 5 NA NA NA 80

BC32 – – – – X – C NA NA NA NA NA 5 NA NA NA 80

BC 1 – – – – – X C NA NA NA NA NA 6 NA NA NA (Remark 8)

Keys and Remarks to Fig. 777X – Type of glass fitted in the gauge.

A – Applicable.

C – Compulsory.

NA – Not applicable

R – Recommended U shape metallic protector (Fig. 720) and/or acrylic resin tube protector sealed by O-Rings to thestuffing box gland (Fig. 721).

V – External glass protection (sheet of mica or Kel-F) may besuggested for protecting the glasses from corrosive envi-ronmental (see page 42).

1 – Often not necessary. If necessary any usual lighting appa-ratus can be utilized. Apply to our Technical Service fordetails.

2 – Apparatus for lighting of the meniscus at water level fromlower position, not explosion-proof (Fig. 826). Type GSI.

3 – Apparatus for lighting of the meniscus at water level fromlower position, explosion-proof. Please state relevant Safety Standard (Fig. 827). Type EXGSI.

4 – Apparatus for diffused lighting, explosion-proof. Please sta-te relevant Safety Standard (Fig. 828). Type EXPIN.

5 – Apparatus for bicolour lighting, explosion-proof,type EXGSIBC.

6 – Apparatus for bicolour lighting, explosion-proof,type EXBSIN.

7 – Non-frosting blocks:– for reflex gauge (Fig. 773)– for transparent gauge (Fig. 829) complete with

1 explosion-proof illuminator.Recommended height of blocks, see page 42.

8 – See specific instructions.

9 – Other optionals:– Engraved scales to customer requirements.– Mirrors to transmit image below to the observer.– Closed circuit television equipment, which allows level

reading on monitor in the control room.– Fibre optic remote viewing device to transmit image in the

control room, by means of our Red Cherry System.Ask for peculiar bulletin.

– Specific gravity glass floats can be provided in a transparentlevel gauge where the interface between two immiscibleliquids is to be observed.

– Additional side connected bodies (reflex or transparent) toreach un-interrupted visible length (Fig. 820)

– Heating or cooling tracing tubes for reflex or transparentgauges (Fig. 776).

Standards and QualityGlasses fitted in our level gauges and spare glasses comply withthe following Standards:- DIN 7081 - ONORM M 7354 - MIL G 18498 B- TGL 7210 - OMV H 2009 - Esso Eng. Spec.123- BS 3463 - JIS B 8211 - S.O.D. Spec. 123

Physical and chemical features:- Resistance to bending strain: >150 N/mm2

- Mean coefficient of linear expansion (30 °C to 300 °C):•5,0 . 10-6 . K-1 - DIN 52328

- Transition temperature: 550 °C - DIN 52324.- Hydrolytic resistance: Class 1 - DIN 12111 and ISO 719- Alkali resistance: Class 2 - DIN 52322 and ISO 695- Acid resistance: Class 1 - DIN 12116

Material is always borosilicate glass pre-stressed and opticallytested.”Pre-Stressed”, “hardened”, “extra hard” and similardefinitions are perfectly equivalent.We never use “soda-lime” glasses, since they have quite insuffi-cient features.

Special attention shall be paid to lenght, width, thickness andespecially flatness tolerances. From the latter point of viewBONTT sight glasses have very strict tolerance values, definitelylower than most of the ones on the market. What above ensuresless stress and longer life of glass and joints.

Reflex or transparent glassesThere are two types of sight glasses:

Reflex Glass

Fig. 801

These glasses have one smooth face (external face) and theother face provided with moulded prismatic grooves (internalface).For application with reflex level gauges.

Reflex glasses have following dimensions:

40 BONT

Sight Glasses for Level Gauges

Size Type A Type B Type A-BR13Length Width Thickn. Length Width Thickn. Length Width Thickn.

L B S L B S L B S

1 115 30 17 115 34 17 115 30 172 140 30 17 140 34 17 140 30 173 165 30 17 165 34 17 165 30 17

4 190 30 17 190 34 17 190 30 175 220 30 17 220 34 17 220 30 176 250 30 17 250 34 17 250 30 17

7 280 30 17 280 34 17 280 30 178 320 30 17 320 34 17 320 30 179 340 30 17 340 34 17 340 30 17

- Sizes of glasses are now indicated by Arabic numerals (1, 2, etc.).Former size indication was in Roman numerals (I, II, etc.).

Transparent Glasses

Fig. 802

These glasses have both smooth faces.For application with transparent level gauges.

Transparent glasses have following dimensions:

Size Type A Type B Type A-BT12Length Width Thickn. Length Width Thickn. Length Width Thickn.

L B S L B S L B S

1 115 30 17 115 34 17 – – –

2 140 30 17 140 34 17 – – –3 165 30 17 165 34 17 163 27.6 16.84 190 30 17 190 34 17 188 27.6 16.8

5 220 30 17 220 34 17 218 27.6 16.86 250 30 17 250 34 17 248 27.6 16.87 280 30 17 280 34 17 278 27.6 16.8

8 320 30 17 320 34 17 318 27.6 16.89 340 30 17 340 34 17 338 27.6 16.8

- Sizes of glasses are now indicated by Arabic numerals (1, 2, etc.).Former size indication was in Roman numerals (I, II, etc.).

- Transparent glasses Type A (cross section 30 x 17 mm) areonly spare parts for old pattern level gauges manufactured byus before 1945.

- Transparent glasses type A-BT12 are only spare parts fortransparent bodies type BT12, no more in production.

Fig. 792.4- A special transparent glass isthe round g lass for appl i -cat ion wi th h igh pressure(usually bicolour) level gau-ges. This glass is a small disc(Fig. 792.4) with very stricttolerances.

Joints for glasses- Each sight glass is usually supplied with 2 jonts (1 sealing joint

+ 1 cushion joint).- Length and width of joint are the same as those of the respec-

tive glass.- Reflex glasses type A-BR13 - for fitting in reflex gauges type

BR13 - need special sized joints. See maintenance instructions.- Transparent glasses type A-BT12 - for fitting in transparent

gauges type BT12, no more in production - need special sizedjoints. See maintenance instructions.

Protection for glassesWhen glass protection against corrosive fluids is to be taken inconsideration (including boiler water pressured over 35 bar), youmust remember that only smooth surfaces can be shielded bysmooth sheets having same length and width as sight glass.Therefore:- reflex glasses: only external face can be shielded by mica

sheets or other materials against corrosive environmental agents,- transparent glasses: both faces can be shielded by mica or

transparent polytrifluorochloroethylene (Kel-F) sheets.Protection of the internal glass face in contact with fluid isusually sufficient.Mica sheets inside level gauges are always recommended forapplication with water steam: thickness of mica sheets isusually 0.15 to 0.20 mm.

Non-frosting BlocksFrost on gauge obstructing level reading could develop when levelgauge operates at fairly low temperature.In such cases nonfrosting block of transparent acrylic resin mustbe festened and sealed outside the gauge body.This block shall protrude according to the thickness of the frost(see Fig. 773 and 829).

Recommended protrusion:

Working Protrusiontemperature of fluid of block

–120 °C through –19 °C 038 mm–120 °C through –49 °C 075 mm–150 °C through –99 °C 150 mm–100 °C and lower 200 mm

BONT®

41BONT

bar °C

1,0 99,11,5 110,72,0 119,62,5 126,73,0 132,83,5 138,14,0 142,94,5 147,25,0 151,15,5 154,76,0 158,06,5 161,17,0 164,17,5 167,18,0 169,68,5 172,29,0 174,59,5 176,7

10 179,011 183,212 187,013 190,714 194,115 197,316 200,417 203,318 206,119 208,820 211,422 216,224 220,726 225,028 228,930 232,735 241,440 249,145 256,250 262,755 268,660 274,265 279,570 284,475 289,180 293,685 297,890 301,995 305,8

100 309,5105 313,3110 316,5115 319,8120 323,1125 326,2130 329,3135 332,2140 335,1145 337,8150 340,6155 343,2160 345,7165 348,3170 350,6175 353,0180 355,4185 357,5190 359,8195 361,9200 364,1205 366,1210 368,1215 370,2220 372,0225 374,0

°C °F °C °F °C °F °C °F

–270 –454–260 –436–250 –418–240 –400–230 –382–220 –364–210 –346–200 –328–190 –310–180 –292–170 –274–160 –256–150 –238–140 –220–130 –202–120 –184–110 –166–100 –148–095 –139–090 –130–085 –121–080 –112–075 –103–070 –094–065 –085–060 –076–055 –067–050 –058–045 –049–040 –040–035 –031–030 –022–025 –013–020 –004–017,8 000–015 5–010 14–005 23

0 325 41

10 5015 5920 6825 7730 8635 9540 10445 11350 12255 13160 14065 14970 15875 16780 17685 18590 19495 203

100 212105 221110 230115 239120 248125 257130 266135 275140 284145 293150 302155 311160 320

165 329170 338175 347180 356185 365190 374195 383200 392205 401210 410215 419220 428225 437230 446235 455240 464245 473250 482255 491260 500265 509270 518275 527280 536285 545290 554295 563300 572305 581310 590315 599320 608325 617330 626335 635340 644345 653350 662355 671360 680365 689370 698375 707380 716385 725390 734395 743400 752405 761410 770415 779420 788425 797430 806435 815440 824445 833450 842455 851460 860465 869470 878475 887480 896485 905490 914495 923500 932505 941510 950515 959

520 968525 977530 986535 995540 1004545 1013550 1022555 1031560 1040565 1049570 1058575 1067580 1076585 1085590 1094595 1103600 1112605 1121610 1130615 1139620 1148625 1157630 1166635 1175640 1184645 1193650 1202655 1211660 1220665 1229670 1238675 1247680 1256685 1265690 1274695 1283700 1292710 1310720 1328730 1346740 1364750 1382760 1400770 1418780 1436790 1454800 1472810 1490820 1508830 1526840 1544850 1562860 1580870 1598880 1616890 1634900 1652910 1670920 1688930 1706940 1724950 1742960 1760970 1778980 1796990 1814

1000 18321020 18681040 19041060 19401080 1976

1100 20121120 20481140 20841160 21201180 21561200 21921220 22281240 22641260 23001280 23361300 23721320 24081340 24441360 24801380 25161400 25521420 25881440 26241460 26601480 26961500 27321520 27681540 28041560 28401580 28761600 29121620 29481640 29841660 30201680 30561700 30921750 31821800 32721850 33621900 34521950 35422000 36322050 37222100 38122150 39022200 39922250 40822300 41722350 42622400 43522450 44422500 45322550 46222600 47122650 48022700 48922750 49822800 50722850 51622900 52522950 53423000 5432

42 BONT


type BR14-G11


Fig. 737 Type G11

01 Connection between gauge and cocks are made by end tubesand stuffing boxes.

02 According to the right or left position of the cock handles onthe gauge body, the level gauges are named right-handed orleft-handed. Fig. 795 shows a right-handed level gauge.Usually two level gauges (1 right and 1 left) are installed onsteam vessels

03 According to some Steam Boiler Regulations, the visiblelength of the level gauges installed on steam boilers must benot shorter than a fixed length. Therefore the suitability of thesmaller sizes must be checked.

04 The minimum C. to C; distance (CC min) we can reach bymeans of special end tubes is 15 mm shorter than thedimension shown in the table.

05 When ordering a level gauge please state:- Centre to centre distance between connections (CC)- Standard, Size and Finishing of connections to the vessel- Whether right-handed or left-handed.

06 Flanges are finished to customer prescriptions. Please state:- Standard - Size- Pressure class - FinishingThe inside passage through the gauge is 10 mm.

07 Instead of flanges connections to the vessel can be deliveredwith threaded ends. Standard is 3/4” NPT, union.Other Standard and size on request.



10 Applicable optionals and bolting torque on page 39.

Size C. to C. Length Visible Length Weightdistance of body length of glass

CC min B V G kg

3 285 178 143 165 09.04 310 203 168 190 09.45 340 233 198 220 09.86 370 263 228 250 10.37 400 293 258 280 10.88 440 333 298 320 11.39 460 353 318 340 11.7

Top and bottom cock1 Body2 Plug3 Tightening nut4 Packing sleeve with

2 eyelets, type M2.26 Ring9 Handle

10 Screw and washer11 Head joint12 Stud and nut

Drain cock21 Body22 Plug23 Tightening nut24 Packing sleeve with

2 eyelets, type M1.2

26 Ring29 Handle30 Screw and washer31 Tailpipe joint32 Tailpipe33 Union nut

41 Stuffing box head42 P16 packing ring (16/23,5/10)43 Stuffing box ring44 Stuffing box nut45 End tube46 Tube joint ring47 Drain joint ring

BONT®

160

130 85

150

GVB CC

BONT®

43BONT

Size C. to C. Length Visible Length Weightdistance of body length of glass

CC min B V G kg

1 235 128 93 115 11.742 260 153 118 140 12.143 285 178 143 165 12.934 310 203 168 190 13.305 340 233 198 220 14.076 370 263 228 250 15.057 400 293 258 280 15.508 440 333 298 320 16.509 460 353 318 340 17.20




01 Connections between gauge and cocks are made by endtubes and stuffing boxes.

02 According to right or left position of the cock handles on thegauge body, the level gauges are named right-handed or lefthanded. Fig. 810 shows a right-handed gauge.Usually two level gauges (1 right and 1 left) are installed onsteam vessels.


04 The minimum C. to C. distance (CC min) we can reach bymeans of special end tubes is 15 mm shorter than thedimension shown in the table.

05 When ordering a level gauge please state:– Centre to centre distance between connections (CC)– Standard, Size and Finishing of connections to the vessel– Whether right-handed or left-handed.


070Instead of flanges, connections to the vessel can be deliveredwith threaded ends. Standard is 3/4” NPT, union. OtherStandard and size on request.



10 Applicable optionals and bolting torque on page 39.

Maintenance

Service- After the cocks are first put into service, or after change of

packing sleeves, when the cocks have attained their workingpressure and temperature, open the cocks and tighten thetightening nuts (3 and 23)Repeat operation during the first hours of service and ifleakage occurs.

- Follow up all joints (11, 31, 41).

Spare partsOne complete set of sealing elements for 1 level gauge consists of:- 2 Packing sleeves type M2.2 (item 4),- 1 Packing sleeve type M1.2 (item 24),- 2 P16 packing rings (item 42),

2 Head joints (item 11).

VBCC

160

130 85

150

G

Germany Bonetti Armaturen GmbH In den Fritzenstücker 4 - D-65549 LIMBURG / LAHNTel. +49 6431 72041Fax +49 6431 72066

Australia - New Zealand Bonetti Australia Pty Ltd 136 Union Street (P.O. Box 170) BRUNSWICK, 3056(Australia) Tel. +61 3 3874311 - Fax +61 3 3880698

In Milan, in 1905 Cesare Bonetti opened a small shopand manufactured to order any cocks for the localrequirement.In the early twenties this small firm took on a newindustrial look and moved towards production andtrade of industrial valves only.Bonetti is, by this time, becoming a well-known com-pany for production of piston valves, sleeve-packedcocks and glass level gauges.Later the production range, bearing the BONT registe-red trade-mark includes the new valves for high pres-sure and temperature meeting the strictest requi-rements of the most advanced technology, besidesdouble-sealing valves, bellows valves, diaphragm val-ves, magnetic level gauges.After two enlargements the company in 1969 moves tothe new Garbagnate Milanese Works where Bonetti's

typical trend for research, development and designaccuracy has more opportunity to expand.Certification according to ISO 9001 / UNI EN 29001.

Facilities:

Enclosed surface 66,000 sq.m

Offices building (with car parkingbelow) for three stories 2,200 sq.m

Facilities building (mess-hall, lockerrooms, sanitary department, etc.)

for three stories 2,000 sq.m

Manufacturing shed (includingProduction Department andgeneral Facilities) 17,500 sq.m

I - 20024 GARBAGNATE MILANESE (Italy)Via Cesare Bonetti 17Telephone: +3902 99072.1 - Telefax: +3902 9952483Internet: http://www.cesare-bonetti.it

Export sales: Telephone: +3902 99072444Telefax: +3902 99072400E-mail: [email protected]

Branch Offices in Foreign Countries

Ask for information about our International Network of Technical Sale Representatives.

This catalogue is exclusive property of Cesare Bonetti S.p.A.Any unauthorized reproduction, in total or in part, of thiscatalogue shall be prosecuted.Products and data sheets on this catalogue reflect currentstandard production. Cesare Bonetti S.p.A. reserves the rightto carry out amendments to products and materials.

Amendments or modifications to drawings and materials canbe done also to comply with particular Customer’s request ortechnical specifications.

Documents

Glass Level Gauges