applications and typesrubber expansion joints

data sheet - RJ 001RADCOFLEX® reserves the right to change product specifications without notice. RADCOFLEX® Trade Mark of Radcoflex Australia Pty Limited. © 2006/07

moulded spherical type -These are the economical rubber joints being mass produced in single and double sphere styles. They are manufactured by the high pressure moulding of heat resisting rubber with a high tensile fabric reinforcement.

This produces a joint of lighter construction than with the hand-built joints resulting in a more flexible joint with the lower spring forces thereby reducing stress on the system.

The spherical shape is inherently stronger than the spool arch type with internal pressure forces being distributed over a larger surface area.

Styles FSF, FTF and UTU described in these data sheets are moulded spherical type rubber joints. These are fitted with floating metal end connections for easy installation.

high spool arch type –These are hand built to the specific requirements of the installation thereby ensuring a long working life. The joints have moulded integral flanges which provide a tight seal to the mating surface.

High Spool Arch joints can be supplied with a filled arch to improve flow rates, reduce flow turbulence and limit the collection of solids in the arch.

wide arch types –The wide arch type combines many of the features of both the moulded spherical and hand built spool types.

The type incorporates a spherical long flowing arch with moulded integral flanges. The long flowing arch provides improved movement capabilities over the spool type and reduced turbulence in the medium conveyed. The integral flanges provide a tight seal to the mating surface.

applicationsFlexible rubber joints provide a cost effective solution for demanding industrial applications conveying water, air, mild corrosive fluids and odours, with the added advantage of reducing fluid-borne noises.

The rubber joints are primarily used to :- absorb or isolate vibration- compensate for system misalignments- protect system against startup and pressure surges- absorb water hammer and vibration noises- absorb pipework stresses

They have a number of applications in the air conditioning, heating and ventilating, power gen-eration, water treatment, pulp and paper, chemical, pollution control, marine, mining and industrial process piping industries.

Rubber expansion joints compliment the Radcoflex range of metal bellows expansion joints offering a low cost alternative for certain simple movement, low temperature and mildly corrosive applications. Rubber joints can also provide a ‘quieter’ alternative to metal joints as system generated sounds lose their energy as they travel axially through the rubber section.

standardsRadcoflex flexible rubber expansion joints materials meet or exceed the requirements of the Rubber Expansion Joint Division, Fluid Sealing Association (FSA) for Standard Class I and II, and for some applications Class III.

rubber joint typesFlexible rubber joints are generally manufactured in three types – the moulded spherical type, the conventional hand built high spool arch type and the wide arch type. The three types all have their advantages.

Radcoflex can supply all three.

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rubber materialsrubber expansion joints

data sheet - RJ 001RADCOFLEX® reserves the right to change product specifications without notice. RADCOFLEX® Trade Mark of Radcoflex Australia Pty Limited. © 2006/07

rubber typesFlexible rubber joints can be manufactured from a range of elastomer materials including:Chloro ButylEPDMHypalon*NaturalNeopreneNitrile (Buna-N)

The joints may consist entirely of the one type of rubber or a combination with one type of rubber as the inner ply and a different rubber as the outer cover.

The selection depends upon a variety of factors including temperature and the medium to be conveyed. A copy of a Rubber Compatability Table is available from Radcoflex upon request.

* Hypalon and Neoprene are trademarks of DuPont Dow Elastomers

technical characteristics

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ElastomerCommon Name

Chemical Name

ANSI/ASTMD1418-77

Hardness Range:Duro A

Specific Gravityof Base

Temperature ˚C- min service- max service

Chlorobutyl

Chloro -Isobutylene

Isoprene

CIIR

40-75

0.92

-25120

EPDM / EPT

EthylenePropylenePolymer

EPDM

30-90

0.86

-30150

Hypalon

Chlor -Sulfonated

Polyethylene

CSM

40-95

1.12

-40135

Neoprene

Poly -Chloroprene

CR

30-95

1.23

-25105

Nitrile / Buna-N

ButadieneAcro-Nitrile

NBR

30-100

0.98

-35115

Gum / Natural

Polyisoprene

NR/IR

30-90

0.93

-3085

technical aspectsrubber expansion joints

data sheet - RJ 001RADCOFLEX® reserves the right to change product specifications without notice. RADCOFLEX® Trade Mark of Radcoflex Australia Pty Limited. © 2006/07

force required to moveThe force required to move a rubber expansion joint is defined as the total load required to deflect the joint a distance equal to the maximum rated movement of the joint. This force is expressed in kgs for compression, elongation and lateral movements and is based upon zero pressure conditions. Refer Radcoflex for details on style HS joints.

types of movementFlexible rubber joints are installed in a piping system to absorb movements in three directions:-- Axial - the movement of elongation and compression along the centre line- Lateral - offset movement from the centre line- Angular - offset bending about the centre line

Style FSF, FTF and UTU joints are not capable of absorbing more than one movement at a time (i.e. non-concurrent), nor absorbing torsional (i.e twisting) movement.

Styles WA and HS can absorb different movements concurrently and can accept torsional movement of 1º-2º when the joint is at its free or neutral length, however every effort should be made to design such movement out of the system.

pressure and temperatureThe pressures listed in the product data sheets are the nominal operating (working) pressures at a temperature of 80ºC (170ºF) for correctly anchored and guided expansion joints.

The test pressure is 1.5 times the positive nominal operating pressure held for 10 minutes.

The burst pressure is approximately 4 times the operating pressure on diameters up to 300mm, and approximately 3 times for larger diameters.

The pressure rating of the joint is reduced as the temperature rises above 80ºC. Below is the correction factor to be applied.

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press/tempcorrection factor

maximum workingpressure(x factor)

operating temperatures

80ºC 85ºC 90ºC 95ºC 100ºC 105ºC

x 1.0 x .92 x .83 x .75 x .67 x .60

limit and control rodsrubber expansion joints

data sheet - RJ 001RADCOFLEX® reserves the right to change product specifications without notice. RADCOFLEX® Trade Mark of Radcoflex Australia Pty Limited. © 2006/07

movement controlLimit or Control Rods can also be used to control the movement by allowing the expansion joint to extend only to a predetermined extension setting, or to move axially only within a specific range.

This is acheived by placement of threaded nuts on the control rods to the limits of movement required. This setting must be no greater than the maximum allowable extension movement of the rubber joint as per the expansion joint specification tables in the data sheets.

control rod systemThe control rod system consists of control rod plates drilled to the flange drilling, control rods and nuts. The control rod plates are bolted into position during the installation of the rubber joint.

A control rod consists of two plates and one rod.

Control rods can be fitted to flexible rubber expansion joints to enhance its pressure capability in unanchored systems, and to control the movement of the joint within planned and designated capabilities.

The control rods are placed across an expansion joint in line from flange to flange. In metal expansion joint terminology these would be called ‘tie rods’

pressureFlexible rubber expansion joints should be installed between two fixed anchor points in a piping system - see ‘installation instructions’ data sheet.

Anchored Systems - control rods are not required to be fitted to the joint piping systems that are correctly anchored and where the joint will be operating within an acceptable movement range for that joint - see the expansion joint specification tables in the data sheets

Unanchored systems - control rods are recommended for all applications where the piping system is not correctly anchored. In particular, control rods must be used when the pressure exceeds :

See Data Sheet RJ 021 for control rod information for style WA and HS Joints

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nominal bore

25-100mm125-250300-350400-600650-750

Style FSF

1240 kPa930640310240

Style FTF

930 kPa930640310240

conrol rod ratingsfor wa and hs stylerubber expansion joints

data sheet - RJ 001RADCOFLEX® reserves the right to change product specifications without notice. RADCOFLEX® Trade Mark of Radcoflex Australia Pty Limited. © 2006/07

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The Technical Handbook of the Rubber Expansion Joint Division of the Fluid Sealing Association nominates the following specifications for control rods. This is a guide and depends upon thickness of the control plates and rods used.

25

32

40

50

65

80

100

125

150

200

250

300

350

400

450

500

600

650

700

750

800

850

900

950

1000

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

10

10

10

10

10

10

10

10

13

13

20

20

20

20

20

20

25

25

32

32

32

40

40

40

40

13

13

13

16

16

16

16

16

16

20

22

25

25

32

32

32

32

32

40

40

40

40

40

40

40

6540

5720

3510

4550

3640

3040

2140

1620

1280

1120

1120

1100

770

770

640

540

510

420

440

480

430

490

470

430

280

-

-

-

-

-

-

3210

2430

1910

1680

1680

1650

1150

1150

970

810

750

640

670

720

640

730

710

640

430

-

-

-

-

-

-

4280

3240

2550

2240

2240

2200

1530

1560

1280

1080

1010

850

890

970

860

980

950

860

580

-

-

-

-

-

-

-

-

-

-

3360

3310

2300

2340

1930

1620

1520

1280

1340

1450

1290

1480

1420

1290

870

-

-

-

-

-

-

-

-

-

-

-

-

-

3120

2580

2170

2020

1700

1790

1930

1730

1970

1900

1730

1160

1

1-1/4

1-1/2

2

2-1/2

3

4

5

6

8

10

12

14

16

18

20

24

26

28

30

32

34

36

38

40

Nominal BoreJoint / Pipe

mm ins

Standard No.of Control Rod

Sets

Control Platethickness mm

Control Rodthickness mm

Maximum Surge or Test Pressureof the System kPa

No. of Control Rods recommended2 3 4 6 8

installation instructionsrubber expansion joints

data sheet - RJ 001RADCOFLEX® reserves the right to change product specifications without notice. RADCOFLEX® Trade Mark of Radcoflex Australia Pty Limited. © 2006/07

maintenanceIt is recommended to check bolt tightness one week after installation. For systems with significant temperature changes, the bolt tightness should be regularly checked.

At the same time, the outer cover of the joint should be examined for signs of damage or failure.

To ensure a long service life, elastomer expansion joints require careful installation procedures.

anchors and guidesRubber expansion joints should be installed between two fixed anchor points in a piping system. The pipe system needs to be rigidly anchored on both sides of the expansion joint to control expansion or contraction. The pipe anchors must be capable of withstanding the significant movements imposed on the system by internal pressure and temperature fluctuations.

Where correct and adequate anchoring is not possible, the rubber joints must be fitted with Control Rods - see ‘limit and control rods’ data sheet.

gasketsRubber expansion joints when mated to flat face plate flanges do not need gaskets, however a gasket may be required if the mating flange is raised face to ensure a proper seal and to prevent the metal flange from damaging the rubber vanstone face seal.

Ensure mating flanges are clean and reasonably smooth before installation.

It is advisable to apply a thin film of graphite dispersed in glycerine or water to the rubber face of style HS and WA joints before installing the joint. This makes the initial installation and any subsequent removal of the joint easier to perform.

vacuum applicationsRubber expansion joints should not be installed extended on vacuum applications.

spring mounted installationControl rods should always be used when the joints are used in conjunction with spring mounted equipment.

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installation instructionsrubber expansion joints

data sheet - RJ 001RADCOFLEX® reserves the right to change product specifications without notice. RADCOFLEX® Trade Mark of Radcoflex Australia Pty Limited. © 2006/07

guide to correct installationTo ensure a long service life, elastomer expansion joints require careful installation procedures.

• Install the nut and spring washer on the side opposite the elastomer element (on the piping system side).

• Always use spring washers to avoid nuts working loose when expansion joints are vibrating.

• Always install expansion joints at proper length.

• When bolting the expansion joint to the pipe work flanges, follow the diagrams on this page.

• When installing nuts to bolts tighten as per (1) (2) (3) (4) procedure and tighten diagonally.

• Determine T dimension in free state and tighten bolts till dimension is half of T i.e. T/2 - do not overtighten as this will damage the vanstone face seal.

• The installed F/F tolerance is ± 3mm (1/8”)R

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