STEAM TRAPSSTEAM TRAPS

Trap BasicsTrap BasicsWhenever possible, steam traps should be located ~2 foot from, and Whenever possible, steam traps should be located ~2 foot from, and below the discharge of the equipment.below the discharge of the equipment.

Strainers, whether built in or separate, are recommended with all Strainers, whether built in or separate, are recommended with all steam traps.steam traps.

Install ball (or gate) valves before and after the steam trap to ease Install ball (or gate) valves before and after the steam trap to ease maintenance by isolating the trap from the rest of the system.maintenance by isolating the trap from the rest of the system.

Trap BasicsTrap BasicsUnions should be installed between the isolating valves and steam Unions should be installed between the isolating valves and steam trap so that the trap can be easily removed and replaced as trap so that the trap can be easily removed and replaced as required.required.

Blowdown valves are recommended at strainer outletBlowdown valves are recommended at strainer outlet

A test valve or a sight flow indicator are recommended to determine A test valve or a sight flow indicator are recommended to determine if system is operating and functioning properlyif system is operating and functioning properly

Pipe Scale & DirtPipe Scale & DirtWhen new piping is installed, chunks of When new piping is installed, chunks of solder, fragments of metal parts, solder, fragments of metal parts, packing, and even nuts and bolts are packing, and even nuts and bolts are often left inside.often left inside.In older piping systems, there is a build-In older piping systems, there is a build-up of scale and dirt that can break free up of scale and dirt that can break free and travel through the steam system.and travel through the steam system.Pipe scale and dirt can permanently Pipe scale and dirt can permanently damage steam equipment, especially damage steam equipment, especially steam traps. To overcome this:steam traps. To overcome this:– Install a strainer prior to every steam Install a strainer prior to every steam

traptrap– Utilize a dirt pocket in front of the Utilize a dirt pocket in front of the

trap to accumulate dirt and scale.trap to accumulate dirt and scale.

Steam Main Drip LegSteam Main Drip LegSteam main drip pockets are recommended at every Steam main drip pockets are recommended at every horizontal and vertical change of direction in piping, and horizontal and vertical change of direction in piping, and in front of all equipment such as control valves, PRVs, or in front of all equipment such as control valves, PRVs, or shut off valves because these are natural collection shut off valves because these are natural collection points.points.

The distance between drain pockets should decrease as The distance between drain pockets should decrease as the steam main size increases because of the additional the steam main size increases because of the additional amount of energy (water hammer) larger mains have that amount of energy (water hammer) larger mains have that could cause damage.could cause damage.

A rule of thumb for spacing drip pockets is the higher the A rule of thumb for spacing drip pockets is the higher the pressure or larger the main, the closer the spacing.pressure or larger the main, the closer the spacing.

Steam Main Drip LegSteam Main Drip LegFor steam main up to 6”, a full size drip leg should be For steam main up to 6”, a full size drip leg should be installed. Over 6”, a collecting leg of ½ of the pipe size installed. Over 6”, a collecting leg of ½ of the pipe size can be utilized, as long as it is not under 6”can be utilized, as long as it is not under 6”The take off of the steam trap should be at a point ~3” The take off of the steam trap should be at a point ~3” above the lower level of the drip leg, draining by gravityabove the lower level of the drip leg, draining by gravity

Back Pressure EffectBack Pressure Effect

The general rule of The general rule of thumb for calculating the thumb for calculating the back pressure of back pressure of condensate lift condensate lift installations is 1psig installations is 1psig back pressure for each back pressure for each 2 foot of vertical lift. For 2 foot of vertical lift. For low pressures, use low pressures, use 1psig per foot for lift.1psig per foot for lift.

Bypass LoopsBypass LoopsBypass loops are needed when the trap capacity can Bypass loops are needed when the trap capacity can not meet the start-up requirements.not meet the start-up requirements.– CAUTION: Bypass could be inadvertently left open, CAUTION: Bypass could be inadvertently left open,

allowing large amounts of live steam to be lost when hot allowing large amounts of live steam to be lost when hot running load is achieved.running load is achieved.

Most steam trap manufactures discourage the use of Most steam trap manufactures discourage the use of bypass loops. By selecting a trap with high start-up bypass loops. By selecting a trap with high start-up capacity, the bypass is not needed.capacity, the bypass is not needed.

Traps in ParallelTraps in ParallelParallel traps are used in critical process applications Parallel traps are used in critical process applications where the unit can not be shut down for servicing. One where the unit can not be shut down for servicing. One trap can be on while the other is serviced.trap can be on while the other is serviced.Good alternate to the bypass loop installation because Good alternate to the bypass loop installation because it eliminates the possibility of blowing live steam it eliminates the possibility of blowing live steam through an inadvertently open bypass valve.through an inadvertently open bypass valve.– Negative: More ExpensiveNegative: More Expensive

Space Heating EquipmentSpace Heating EquipmentIn order to facilitate good drainage from the equipment, a In order to facilitate good drainage from the equipment, a vertical leg (at least 12” long) should be installed on the vertical leg (at least 12” long) should be installed on the bottom of the equipment.bottom of the equipment.If the unit heater has a modulating valve on the inlet, If the unit heater has a modulating valve on the inlet, consideration must be given to the consideration must be given to the ΔΔP across the trap so P across the trap so that there is always enough steam pressure to remove that there is always enough steam pressure to remove condensate.condensate.

Space Heating EquipmentSpace Heating EquipmentThe installation of a vacuum breaker is vital whenever The installation of a vacuum breaker is vital whenever steam is controlled to the unit heater with a modulating steam is controlled to the unit heater with a modulating control valve.control valve.An air vent installed at the opposite corner from the inlet An air vent installed at the opposite corner from the inlet steam supply helps remove air from the remote areas of steam supply helps remove air from the remote areas of the equipment.the equipment.

Shell & Tube Heat ExchangersShell & Tube Heat Exchangers

Optional vacuum breaker installed to allow free Optional vacuum breaker installed to allow free drainage of condensate when system is off.drainage of condensate when system is off.The air vent is used to remove the air that may The air vent is used to remove the air that may be introduced through the opening of the be introduced through the opening of the vacuum breaker or from the steam supply.vacuum breaker or from the steam supply.

Delta ElementDelta Element

Delta Cycle-Start upDelta Cycle-Start up

At cold start up, At cold start up, stem is full open to stem is full open to allow high flow allow high flow capacitycapacityOnly one moving Only one moving part for simple part for simple designdesign

Delta Cycle-ClosingDelta Cycle-Closing

Stem starts to close Stem starts to close as condensate as condensate temperature temperature increasesincreasesFlow will modulate Flow will modulate as condensate is as condensate is formedformed

Delta Cycle-throttleDelta Cycle-throttle

Stem throttles shut Stem throttles shut when condensate when condensate reaches temperature reaches temperature of saturated steamof saturated steamExpansion chamber Expansion chamber allows extra capacity allows extra capacity before shut offbefore shut off

Delta Cycle-Shut offDelta Cycle-Shut off

Stem is tightly shut Stem is tightly shut when steam is when steam is presentpresentSingle, open blade Single, open blade design allows faster design allows faster response to response to temperature temperature changeschanges

The Delta CycleThe Delta Cycle

Blowing Steam vs. Flash SteamBlowing Steam vs. Flash Steam