Pumping Trap Applications

Open Systems
Open systems are vented to atmosphere and are used when it is necessary to drain condensate from multiple sources and pressures.

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This diagram illustrates condensate drainage to a vented receiver with overhead condensate return. Use of the pumping trap, combined with proper sizing of the steam trap, receiver and vent lines, assures successful drainage of the heat exchange space under low pressure.

Closed Systems
Closed systems operate at equipment pressure and are not vented to atmosphere. A closed system application has a dedicated pumping trap for each piece of equipment being drained.

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This diagram illustrates drainage from a heat exchanger in a closed-loop system where the supply pressure may be higher or lower than the back pressure. If the heat exchanger pressure exceeds the back pressure, the pumping trap will be idle and the steam trap will prevent the steam from "blowing through" into the return line.

NOTE: Closed-loop systems can be applied only to a single piece of equipment being drained.

Note 1: Steam supply drip line may be tied back into the return line, the receiver or sent to the drain.

Note 2: Vent line may be tied back into the heat exchange space if the pressure drop across the heat exchanger is less than 0.5 psi. (.35 bar)

Note 3: If the alternative vent connection is used, the use of vacuum breakers would not be necessary because pressure will be equalized in the heat exchanger, receiver and pumping trap, allowing continuous drainage.

Modulating Pressure
Modulating steam pressure means that the pressure in the heat exchanger unit being drained can vary from the maximum steam supply pressure to vacuum under certain conditions.

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This diagram illustrates drainage of a heat exchanger in a closed-loop system where the system pressure never exceeds the back pressure. Please note that the equipment is not trapped. In this scenario, the pumping trap will act as both a steam trap and a pump.

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This diagram illustrates a system that modulates in pressure with a pressurized return main. When system pressure is above the return line pressure, condensate will be returned. When the system pressure falls below the return line pressure, a flooded coil results. The next diagram illustrates one possible solution to this common problem.

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This diagram illustrates a closed-loop system where the system pressure will modulate above and below the return line pressure. When the system pressure exceeds the return line pressure, the pumping trap will be idle and the steam trap will prevent steam from "blowing through" into the return line. When the system pressure falls below the return line pressure, the pumping trap will begin to operate, returning the condensate to the return line. The vent line of the pump will be tied back into the coil, forming an equalized pressure loop that will allow continuous drainage.

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