Pump & Trap Combinations How a Pump-Trap Works
PUMP Mode The pressure in the HX has now dropped to 10 PSIG . This was in response to a fall off in demand of hot water. Based on this particular size HX, 10 PSIG steam will heat 32 GPM of water. Since back pressure is 15 PSIG, the system is stalled and condensate is beginning to back up into the system and the float continues to rise.
Vent Outlet: Open position, allowing pressure in the pump tank to equal pressure in the heat exchanger, allowing condensate to freely enter Pump-Trap by gravity. Motive Inlet: Closed position
50 PSIG
10 PSIG
Venting
50 PSIG
Condensate level rising
balancing line
15 PSIG
2 PUMP TANK FILLS: Inlet steam pressure falls below back pressure. Steam can no longer push the condensate through the Steam Trap.
Condensate rises to a level that the float triggers the inlet steam valve and closes the vent valve. Full line pressure steam (50 PSIG) enters thru the inlet valve on top of the pump body to discharge the condensate. Because of check valves, condensate will not flow back to HX and is discharged to the condensate return line. Unit will continue to operate and cycle in pump mode as long as pressure in the HX is below back pressure. Pump-Trap will also operate in vacuum conditions.
Vent Outlet: Closed Motive Inlet: Open; steam pressure (50 PSI) enters tank and discharges condensate.
50 PSIG
10 PSIG
50 PSIG
Condensate level falling
Motive steam pressure discharges condensate
balancing line
3 PUMP Mode: Pump is activated. When the pump tank has filled to the trip point, the mechanism triggers, opening the motive gas inlet valve and simultaneously closing the vent valve. This allows motive pressure to enter the pump body, which drives the condensate thru the outlet check valve and into the condensate return line. During the discharge cycle, the liquid level and the float inside the pump tank drop. When the lower trip point is reached, the mechanism closes the motive inlet valve and opens the vent valve so the pump-trap can fill on the next cycle.
15 PSIG
40
Tel: 610-495-5131 • Pottstown PA • USA •• www.watsonmcdaniel.com
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