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Flashcards in Steam Traps Deck (20)
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What causes air to be drawn back into a steam system during operation?

The pressure in the system drops below atmospheric pressure


How much back pressure should be expected against traps discharging directly to atmosphere, or into a dry gravity return line



What is the designation of a system in which the return lines carry both condensate and gases to a receiver tank?

Dry return


What term is used to describe the result of a high velocity slug of water striking an obstruction in a steam line?

Water hammer


What is usually an indicator that there is a need to re-examine the trap situation?

Repairs are required too frequently


What actuates the control element to open a thermostatic trap

Temperature of the fluid flowing to the trap


Which trap combines the air handling capabilities of a thermostatic vent with the condensate handling ability of a float trap?

Float and thermostatic


What is the safety factor used to calculate a trap capacity?

Two times the rated capacity of the heat exchanger


What is most affected by the difference in pressure existing across the orifice of a trap?

Rate and flow


Which trap is recommended for the end-of-main service on low pressure steam system?



What valves and fittings are required ahead of the trap when installing an F&T trap station?

Gate valve, strainer and union


Where should the discharge from the trap enter the condensate return lines?

Into the top of the return lines


How much pressure differential is required before an inverted bucket trap will cycle properly?

14kPa (2psi)


What should be installed if a trap has to push condensate up a riser to a return line?

Check valve downstream of the trap


What is the piping configuration used to collect condensate from a main called?

Drip point or drip leg


What is the minimum size of drip leg that should be used on an 8" NPS main?

100mm (4")


What is a valve on a strainer used for?

To blow down the strainer


What is the most accurate method of determining how well the trap is functioning ?

Observe the discharge from a test tree connection downstream of the trap


What does an unusual lack of heat output from a single steam heating unit indicate?

Failure of the trapping system to remove the condensate


What causes the sensors to signal the lack of condensate immediately ahead of the trap in a conductivity sensor?

The presence of steam or air at the level of the contacts