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Xylem Bell & Gossett Hoffman Speciality Series, Engineering Data Manual

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Xylem Bell & Gossett Hoffman Speciality Series Engineering Data Manual Download Page 35

36

WET RETURN

SUPPLY MAIN

PACKLESS
RADIATOR 
VALVE

REDUCER

CAN BE 

REDUCED

(Never Less

than 3/4 ")

NOT LESS

THAN 18"

WATER LINE OF BOILER

VENT

VALVE

DRY RETURN

SUPPLY MAIN

PACKLESS
RADIATOR 
VALVE

VENT

VALVE

TRAP

MINIMUM COOLING LEG 5'-0" LONG

RISER

PITCH DOWN FROM HERE  

PACKLESS 

RADIATOR 

VALVE

AIR VALVE

SUPPLY MAIN

PITCH DOWN FROM HERE  

PACKLESS 

RADIATOR 

VALVE

AIR VALVE

Upfeed connection to radiator

Radiator connection taken

from up or downfeed riser

One pipe steam systems radiator connections

Downfeed connections with wet return

Downfeed connections dripping riser into condensation pump return

Summary of Contents for Bell & Gossett Hoffman Speciality Series

Page 1: ...Hoffman Specialty Steam Traps HS 203C ENGINEERING DATA MANUAL Application Selection Installation Piping Diagrams...

Page 2: ...ng Pressure Limits 17 Installation and Calculating Differential Pressure 18 Drip Traps for Distribution Pipes 20 Chapter 3 Selecting Traps for Heat Exchangers 24 Lock out Traps for Start up Loads 27 D...

Page 3: ...charge To assure condensate drainage there must be a positive differential pressure across the trap under all load conditions Water Hammer When a trap drains high temperature conden sate into a wet re...

Page 4: ...ntages Completely drains condensate at satura tion temperature Modulates to handle light or heavy loads continuous discharge equal to condensing load Large ports handle high capacities Separate thermo...

Page 5: ...hon type or tilting kettles 6 INLET OUTLET COVER BODY V BUCKET A STEAM BUBBLES THROUGH WATER INLET OUTLET COVER BODY V BUCKET A STEAM BUBBLES THROUGH WATER INLET OUTLET COVER BODY V BUCKET A BUCKET TR...

Page 6: ...inexpensive Fast response to changing conditions Fail open models Disadvantages Water hammer can damage bellows Superheat can damage bellows if it exceeds trap temperature rating Pressure limit of 125...

Page 7: ...re maximum tem perature is required Outdoor applications including drips on steam mains Drying tables Tire mold press and vulcanizing equipment Dry kilns Pressing machines Rugged applications superhea...

Page 8: ...hitting the disc Operating As the condensate nears saturation tempera ture greater amounts of flash steam will appear Some of the flash steam escapes to the area above the disc causing the pressure ab...

Page 9: ...sed only as a guide 10 Chapter 1 Condensate must be completely removed at saturation condition to prevent water hammer Type of Steam Trap Required Based on System Conditions Modulating load wide range...

Page 10: ...p 3 Apply Safety Factor A SFA Recommended 1 Float Thermostatic Trap 1 5 to 2 5 2 Bucket Trap 2 to 4 3 Thermostatic 2 to 4 4 Disc Traps 1 to 1 2 See specific applications B The SFA Will Depend On Degre...

Page 11: ...cury 13 6 inches water column Size condensate receivers for 1 min net storage capacity based on return rate Size condensate pumps at 2 to 3 times condensate return rate W x Sh x T2 T1 L x T Helpful Hi...

Page 12: ...of objects as opposed to latent heat In the sat uration tables it is the Btu remaining in the condensate at saturation temperature Latent Heat The amount of heat expressed in Btu required to change 1...

Page 13: ...5 353 3 21 324 1193 867 130 355 3 12 327 1194 867 135 358 3 02 329 1194 864 140 361 2 92 332 1195 862 145 363 2 84 335 1196 860 Specfic Heat Content Latent Pressure Saturated Volume Btu per Ib Heat of...

Page 14: ...600 Pipe Size PRESSURE PSI GAUGE Inches 5 10 15 30 50 75 100 125 200 250 1 2 30 40 45 60 90 120 150 180 270 330 3 4 55 70 80 110 160 220 280 340 510 620 1 90 110 125 180 270 390 460 560 840 1020 11 4...

Page 15: ...the flash loss and required heating of make up water to replace the flash loss The amount of make up water and water cost can also be determined using this form How to Calculate Your Own Flash Steam...

Page 16: ...al operating pressure is higher than the seat rating the differential pressure across the seat will prevent the trap from opening Thus the trap must be selected for the maximum differential pressure t...

Page 17: ...e of the trap required Piping Details A dirt pocket should be provided ahead of the steam trap to collect scale and dirt A shut off valve should be provided ahead of the trap to permit service Straine...

Page 18: ...ressure in the return line minus static head in the discharge piping Trap capacities should be calculated at the minimum differential pressure to assure com plete condensate drainage Lifts in the retu...

Page 19: ...ators The size and type of drip traps used will depend on the method used in heating the steam mains to final pressure and tempera ture The two methods commonly used are automatic start up and supervi...

Page 20: ...x T1 T2 x 114 L W Weight of pipe see table below for weight per ft T1 Steam temperature at saturation T2 Initial pipe temperature at ambient L Latent heat of steam at final operating pressure 114 Spec...

Page 21: ...a gravity return line this would be 30 psi Step 4 Select the trap Based on the previous description of traps if the trap from a steam header is not subject to freezing conditions the normal selection...

Page 22: ...o allow conden sate to flow back into main When the branch line is over 10 ft pitch the branch line toward the control valve and install a steam trap The steam trap should be as close to the control v...

Page 23: ...ing rate at design pressure is not the only load the trap must handle The condens ing load of a heat exchanger designed for 15 psi may in fact be in excess of 90 at 0 psig When the heat exchanger is s...

Page 24: ...ws Select capacity based on maximum con densing load at minimum differential pressure that can occur The heat exchanger manufac turer can provide this information No lifts should be installed in the r...

Page 25: ...bottom outlet for the condensate drainage When a modulating steam regulator is used on the steam to water heat exchanger the vacuum breaker will allow air to enter to pre vent an induced vacuum from h...

Page 26: ...ground steam lines during start up The low pressure trap con nected to an open drain or sump drains con densate during start up When the steam line pressure exceeds the trap rating it will close and r...

Page 27: ...ted to the overhead return line with a check valve to prevent backflow The second trap may be a low pressure trap When condensate backs up 4 inches it will drain into the second trap which will drain...

Page 28: ...ized one pipe size smaller than the trap inlet but never less than 1 2 pipe size The coils in Figures 2 3 and 4 are of the con tinuous type Coils are often multi circuited A safety factor of 4 is need...

Page 29: ...y The excellent air handling capability of Thermostatic Traps makes them suitable for trapping applications where quick air removal is required For example batch processes resulting in on off operatio...

Page 30: ...heat load is required Small low pressure unit heaters up to 15 psi often use Thermostatic Traps Large unit heaters or those operating at higher pressure may use F T as first choice and Bucket Traps a...

Page 31: ...elation to other types of traps This makes them attractive for heating systems where many large numbers of traps are required Trap Damage from Water Hammer When automatic temperature controlled sup pl...

Page 32: ...NPULL SUPPLY MAIN NO PRESSURE WET RETURN REDUCING ELL NOT LESS THAN 24 WATERLINE OF BOILER SUPPLY VALVE WITH CHAINPULL TRAP FULL SIZE OF TAPPING DRY RETURN MAIN MINIMUM COOLING LEG 5 0 LONG SUPPLY VAL...

Page 33: ...CKET SUPPLY LINE STRAINER UNIT HEATER MINIMUM COOLING LEG 5 0 LONG SAME SIZE AS TRAP TRAP TRAP SUPPLY MAIN GATE VALVE GRAVITY VACUUM DRY RETURN MAIN FULL SIZE OF TAPPING Low pressure closed gravity sy...

Page 34: ...UNION PITCH DOWN PITCH DOWN PITCH DOWN Distance from center of radiator tapping to face of sill must be given Straight extended stem on supply valve TRAP DIRT POCKET TRAP GATE VALVE DIRT POCKET DIRT...

Page 35: ...ALVE TRAP MINIMUM COOLING LEG 5 0 LONG RISER PITCH DOWN FROM HERE PACKLESS RADIATOR VALVE AIR VALVE SUPPLY MAIN PITCH DOWN FROM HERE PACKLESS RADIATOR VALVE AIR VALVE Upfeed connection to radiator Rad...

Page 36: ...LEAST 24 DIRT POCKET AT LEAST 18 ABOVE W L WET RETURN AT LEAST 12 One pipe steam systems convector connections Venting concealed radiator of header type air vent tapping in top Dripping end of one pi...

Page 37: ...n at 45 Expansion joint made up of pipe for risers Drop riser branch taken from top of main at 45 Drop riser taken from bottom of main Riser branch taken from bottom of main and dripped into wet retur...

Page 38: ...xi mum heat transfer They are inexpensive and the Hoffman 650 Series allow com plete replacement of the seat and disc without removing the trap body from the line 3 Thermostatic Traps open in response...

Page 39: ...Friction Factor where flow of condensate does not inhibit the flow of steam Basic Chart for Weight Flow Rate and Velocity of Steam in Schedule 40 Pipe Based on Saturation Pressure of 0 PSIG Figure 10...

Page 40: ...le size 41 Velocity Multiplier Chart Figure 10 continued Reprinted by permission from ASHRAE 1972 Handbook of Fundamentals Example of Use of Basic and Velocity Multiplier Charts Given a Weight Flow Ra...

Page 41: ...0 a a 8 228 600 a a Condensate that collects ahead of a steam trap is approximately at saturation temperature and corresponds to the operating pressure As the condensate normally above 212 F drains in...

Page 42: ...to test operation You will be looking for two phase flow in the discharge line Two phase flow has steam in the discharge line and will be over 212 F along the piping Flash steam normally con denses i...

Page 43: ...osion Must distinguish between live steam flash steam Crushed ball failure mode is closed 44 THERMOSTATIC TRAP IS TRAP CYCLING TIGHT CLOSURE BETWEEN CYCLES GOOD TRAP REPLACE OR REPAIR IS RUSHING STEAM...

Page 44: ...AP CAN CYCLES BE HEARD SHUT TIGHT BETWEEN DISCHARGES GOOD TRAP IS RUSHING STEAM HEARD OR SEEN NO YES YES NO CONTINUOUS DISCHARGE LOAD APPROACHING TRAP CAPACITY NO IS RUSHING STEAM SEEN OR HEARD YES GO...

Page 45: ...re The weight of a column of air one square inch in cross section and extending from the earth to the upper level of the blanket of air surrounding the earth This air exerts a pressure of 14 7 pounds...

Page 46: ...ater with steam without mixing the two It may be used for supplying hot water for domestic purposes or for a hot water heating system Cooling Leg A length of uninsulated pipe through which the condens...

Page 47: ...vectors base boards finned tubing coils embedded in floor wall or ceiling or any device which transmits the heat from the heating system to the room and its occupants Horsepower A unit to indicate the...

Page 48: ...n EDR By definition that amount of heating surface which will give off 240 Btu per hour when filled with a heating medium at 215 F and surrounded by air at 70 F The equivalent square foot of heating s...

Page 49: ...ar atmo spheric pressure and returns the condensation to the boiler or receiver by gravity Velocity Pressure The pressure used to create the velocity of flow in a pipe It is expressed as a unit pressu...

Page 50: ...to meet our world s water needs Developing new technologies that will improve the way water is used conserved and re used in the future is central to our work We move treat analyze and return water t...

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