Is.15680.2006-Guidelines for Selecting Steam Traps

8/13/2019 Is.15680.2006-Guidelines for Selecting Steam Traps

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.Boilers and Pressure Vessels Sectional Committee, ME 01

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Boilers andPressure Vessels Sectional Committee had been approved by the Mechanical Engineering Division Council.This standard is based on the experience of the manufacturer and the user organization, prevalent design and operationof steam traps.The composition of the Committee responsible for the formulation of this standard is given at Annex A.For the purpose of deciding whether a particular requirement of this standard iscomplied with the final value, observedor calculated, expressing the result of a test or analysis shall be rounded off in accordance with IS 2: 1960 Rules forrounding off numerical values revised _The number of significant places retained in the rounded off value should besame as that of the specified value in this standard.


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IS 15680:2006

Indian StandardGUIDLINES FOR SELECTION OF STEAM TRAPS

1 SCOPEThis standard covers principle of operation and guidelinesfor selection and operation of various types of steam traps.2 VARIOUS TYPES OF.STEAM TRAPS2.1 Density Operated Traps2.1.1 Ball Float with Thermostatic Air Vents

2.1.1.1 OperationAir entering the trap is immediately discharged through ahigh capacity auxiliary air vent. Condensate causes theball float to rise and place the modulating discharge valvein a position that will pass the condensate continuously asit enters the trap. The condensate level in the trap body ismaintained above the discharge valve to provide a positiveseal against the loss of steam..2.1.1.2 Special features

ab

cd

eogh

jk

Discharge condensate continuously as rapidly as itforms;High air venting capacity through auxiliarybalanced pressure air vent, which is self-adjustingfor varying steam pressures;High thermal efficiency at both light and heavyloads;Continuous modulating discharge does not createpressure disturbances, which may cause erraticcontrol in air heating coils, shell and tubeexchangers, etc;Steam lock release S.L.R. facility available;in line inlet and outlet facility, easy installation atlow cost;Robust, fair resistance to water hammer;Fails in closed position, so no wastage of steamenergy;Unaffected by changes in inlet pressure;Suitable for high condensate loads;

m Available with screwedsocket welde~flanged endconnection; andn Available with in-builtiseparate strainers.

2.1.1.3 Typical applicationsAir unit heaters, hot water heaters, heat exchangers,

converters, dryers, re-boilers, jacketed pans and all processequipment.2.1.1,4 Limitations

a Cannot be us where trap is fitted with air ventand degree of superheat is more than 10OC,and

b Water hammer can damage float.2.1.2 Inverted Bucket Traps2.1.2.1 OperationThe trap body is normally filled with condensate tomaintain a seal around the inverted bucket, which servesas a float to operate the discharge valve. Live steamentering the bucket floats it to close the valve. During theclosed period, condensate collects in the piping at the inletside of the valve until steam floating the bucket leaksthrough a small hole in the top of the bucket and permitsthe bucket to drop and open the valve. The condensate isdischarged. followed by steam, which is required to actuatethe float mechanism. Air can pass through the small holeat the top of the bucket.2.1.2.2 Special features

a Good resistance to water hammer,b Simple and robust mechanism and easy to maintain,c Intermittent discharge,d Discharge condensate and air at steam temperature,e Operate on superheated steam,~ Operate against any back pressure,g Available with in-builtiseparate strainers, andh Available with screwedsocket welded/flanged end

connection.2.1.2,3 Typical applicationsHigh pressure indoor steam main drips and submergedheating coils, ketiles.2.1.2,4 Limitations

abc

I

Low thermal efficiency under varying loads andpressures and some steam loss for operation,Must maintain water seal to avoid continuousdischarge of steam,Must be protected from freezing,


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IS 15680:2006de

Discharge condensate continuously as rapidly as itforms, andBleed hole in bucket has very limited air-ventingcapacity.

.2.2 Temperature Operated Traps2.2 1 Balanced Pressure Thermostatic Traps2.2.1 ;I OperationThe trap is operated by a flexible thermostatic elementfilled with a fluid, which when heated or cooled evaporatesor condenses. Internal pressure changes expand orcontract the element and position the attached valve head.On start-up the coId elements is contracted, and the-wideopen valve remains open to discharge air and sub-coolscondensate. When steam reaches the trap, the elementexpands and closes the trap. When condensatesurrounding the capsule cools to approximately 10C to20C below steam temperature depending on the fillingthe trap opens to discharge condensate.2.2.1.2 Special features

a High air venting capacity fQr fast start-up,bcde

oghjk

Large capacity in small size,Self adjusting will operate without adjustmentsat all pressures within its range,Will not freeze if given free discharge,Use same valve sizes for all pressures within itsoperating range,Minimum parts,Operates in vacuum systems,Modulating discharge,Operate on moderate superheated steam,Discharges condensate close to steam temperature5- l@C sub-cooling ,

m Reacts to temperature changes immediately,n Ensure prevention of live steam loss,p Available with in-built strainers, andq Available with screwed/SW/flanged end

connections.2.2.1.3 Typical applicationSteam radiators, low and medium pressure submergedheating coil, sterilizers, steam tracer, steam mains, pressesand dryers.2.2.1.4 Limitations

a Not suitable for highly superheated steam,b Limited resistance to water hammer and corrosion,

and

c

2.2.2

Not suitable for applications in which condensatemust be dischargedas fast as it is formed.Bi-metallic Thermostatic Trap

2.2.2.1 OperationThe operating principle is based on abalancebetween thesteam force pressure dependent , trying to open thedischarge valve, and the opposing hi-metal forcetemperature dependent which tends to close it. The trapis adjusted so that all saturated steam temperature thehi-metallic force will prevail, while with under-cooledcondensate and air, the force of pressure will prevail andopen the valve trap, the required under-cooling should beminimum possible through out the designed pressurerange. Being the steam force a curve while the hi-metallicforce a straight line, an additional compensating springwill break the straight line to make it follow the curve ofsteam more closely making field adjustment unnecessary.2.2.2.2 Special features

ab

c

deogh

j

Modulating discharge,Condensate is discharged below steamtemperature20 C/30C . Sub-cooling temperature can beadjusted on field,A compensating spring between the hi-metallicelement and-the valve steam ensures that the trapoperation follows the steam curve closely. Thespring does not induce valve spring,May be used on superheated steam,Valve steam acts as a checked valve,Resist water hammer and vibration,Replaceable internal parts,Efficient discharge of air and non-condensablegases, andFreeze proof full size Y pattern integral strainer.

2.2.2.3 Typical applicationsTracing lines, tank heaters, marine applications.2,3 Kinetic Energy Operated Traps2.3.1 Thermodynamic Disc Traps2.3.1.1 OperationsCondensate and air raise the disc and flow freely throughthe trap. When steam reaches the trap, the velocity underthe disc is instantly increased and recompression abovethe disc snaps it on to its seats to give a tight shut off.Heat loss from the small control chamber, which is filledwith a steam, condensate mixture, causes the chamberpressure to decrease to a point at which the valve discopens again to discharge condensate.

2


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2.3.1.2 Special featuresa Compact and light weight;b High resistance to water hammer;cde

9ghjk

Long life due to hardened seat and disc;Only one moving part;Efficient operation under varying loads andpressures;Fast response to changing loads;Discharges condensate at steam temperature,prevent water logging;Discharges air and non-condensable gases;Freeze proo~Operates on superheated steam;

m Available with in-built strainers; and

IS 15680:2006Applications Trap Choice

n Available with screwed/S W/B W/flanged endconnection.

2.3.1.3 Typical applicationSteam main drips, high pressure and superheat, steamtracer lines, unit heaters.2.3.1.4 Limitations

a Not suitable for pressures below 0.25 bar, andb Some models limited 50 percent back pressures,

others suitable for 80 percent of back pressures.3 TYPICAL CHART FOR ST-EAM TRAPSELECTION AND APPLICATIONS

D = thermodynamic disc traps,T = balanced pressure thermostatic traps,

hi-metallic thermostatic traps,inverted bucket traps, andball float with thermostatic air vent traps.

Steam MainsTracing LinesTank

HeaterBatteries

to

Pans

HeatExchangers

D~ingCylinders

Presses

hens

Storage tanksOil tanksAsphalt tanksDye vatsEvaporatorsBlendersSuction heatersUnit heatersDrying roomsGreenhouse coilsFin coilsSugar dryersJacketed pansTilting kettlesBrew kettlesCandy kettlesCheese kettlesSubmerged coilsWater heatersFuel oil pre-heatersPlating tanksPaper dryersPulp dryersRotary dryersCalendarsPlywood pressesMoulding pressesTire mould pressesVulcanizing pressesMilk dryersDressing sterilizersPressure cookersAutoclavesDrum dryers

Ironing MachinesTurbinesMarine Applications

DTD-B

B-T

G-1

G- I

GIG- I

D-T

G-T

I-DD-1D-B


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IS 15680:2006ANNEX AForewor~

COMMITTEE COMPOSITIONBoilers and Pressure Vessels Sectional Committee, ME 01

OrganizationCentral Boilers Board, New Delhi

Alstom Power Boilers Ltd, Durgapur/Delhi

Bharat Heavy Electrical Ltd, Tiruchirapalli

Bharat Heavy Plate Vessels Ltd, Visakhapatnam

Bureau Veritas, Mumbai

Central Electricity Authority, New Delhi

Central Mechanical Engineering Research Institute CSIR), Durgapur

Chief Inspector of Boilers, Chennai

Dcpanment of Atomic Energy, Mumbai

Development Consultants Pvt Ltd, Koikata

Directorate General of Factory Advisory Services Labour Institute,Mumbai

Engineers India Limited, New Delhi

Indian Boilers Manufacturers Association, hlumbatbrdian Gil Corporation Ltd, Vadodara

Indian Register of Shipping, Mumbai

Industrial Boilers Ltd, MumbaiLarsen Toubro Ltd, Mumbai

Moyds Register Asia, Mumbai

Mecon Limited, Ranchi

Representative s)SHRtV. K. GOEL Chairman)

uu. L. AHUJA Alternate)SHRI RAMESHT, YAVAGAL

SHW P. K, PAL 4/ferns/e)SHRIG, UMA SHANKSR

SHJUK. PADMANABANAlfernale)SHRtM. S. V. S. N. MURTHY

SHRIC. H. RAMANAIAH Alrernate)SHRIA, U, M, RAO

SHRIV, KUMAR Aliernate)SHRIA. K. GUPTA

SHRJD. K. GILHOTRAAlternate)SHJUP. R. SAMADDAR

SHRJP. K. SEN Alternate)SHRIT. K. THAMBITHURAI

SHRITHIRU K. REGUNATHAlterna/e)SFiRIH. S, KUSHWAHA

SHN K, K. VAZE Alrernale)SHRI.DIPAKK. SARKAR

SHRJASIM KUMARDE A/ferrrufe)SHRIM. S, TYAGI

SHRIP. K. SAXE~A A1/ernate)-St+R1V, J, N.ALGIRKAR

SHRIA. K. MALIK Alternate)SHRIN. B. TAPASWISHRI U. S, PRASAD

SHRI R. K. SABHARWALA//e.rrrafe)SHRIA. K. SHARMA

SHRI 1.MAJUMDARA//ernate)SHRI R. N. ENGINEERSHRIG. K. SADE~AR

SHRI S. S. IYER Alternate)SHRIB. SARASWAT

SHtuP. K. BANERJEEA[ferna/e)SHRIOM PRAKASH


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IS 15680:2006Organization

Petroleum and Explosive Safety Organization, Nagpur

Projects Development India Ltd, Noida

Tata Iron and Steel Company Ltd, Jamshedpur

The Anup Engineering Ltd, Ahmedabad

The Indian Sugar and General Engg Co~oration, Yamuna Nagar

Therrnm Babxoxk Wilcox Limited, Pune

Welding Research Institute, Tiruchirapall ila personal capacity Qua[iquest Industrial Services, 26 Manak hayNe~vDelhi)

BIS Dirmtorate General

I{epresenlalive s)SHRIM. ANB~NATklAN

SHRIA. N. BISWASAlternate)SHRIA. K, GUPTA

St+ruR. P. SmHA Alternate)

DRM. D. MAHESHWARISHRIC. B. LUNAWAT A/lerna/e)SHKIG. N.V MOHANRAIU

SHRI R. D. CIRISTV A//ernate)SHRISUNILUPPAL

SHRI DHARMENDERSHARMAA/ternafe)SHRIS. A. VANCHINATH

SHRITAMALDUTTAA/ferns/e)StIRI G. UMA SHANKERSHRIM. G. K. RAO

SHRIC. K. VEDA. Scientist F Head MED)[Representing Director General Ex-oflcio)]

Member Secreta~SHRIC, K. VEDA

Scientist F tiead MED), BIS

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Is.15680.2006-Guidelines for Selecting Steam Traps