Typical Pressure Powered Unit in Shippensburg Pump Co.
A non-electric pump operates on the positive displacement principle. Pressure, typically supplied by steam, is used to pump high temperature condensate or other liquids. Generally used where electricity is not readily available or in hazardous environments that prohibit use of electrical power.
Condensate first flows into the receiver (top tank). Condensate then flows, by gravity:
- out the receiver (top tank) drain
- down the interconnected suction piping
- through the suction inlet (swing) checkvalve
- into the inlet of the pump body (bottom tank)
Back pressure keeps the discharge (spring-loaded) check valve closed preventing condensate from flowing out the discharge outlet of the pump body. As the body fills with liquid, the float rises and the water level of the receiver falls. During the filling phase:
- the steam inlet is closed
- the exhaust vent is open
- the suction inlet (swing) check valve is open
- the discharge (spring-loaded) check valve is closed
When the float reaches the high water position (i.e., trip point), the spring of the float mechanism is released which begins the pumping phase. At the trip point, the steam inlet is opened allowing steam to enter into the top portion of the pump body. Simultaneously, the exhaust vent is closed allowing the internal pressure to increase within the pump body.
As the internal pressure increases within the pump body, the suction inlet (swing) check valve is closed stopping gravity flow of condensate into the pump body and causing the water level in the receiver to rise.
Simultaneously, at the high water trip point, the discharge (spring-loaded) check valve opens starting the pumping phase as the pressure within the pump body exceeds the back pressure on the discharge (spring-loaded) check valve-- thus pushing the condensate out the discharge pipe. The water level with in the pump body begins to fall, along with the float.
When the float reaches the low water trip point, the float mechanism reverses action. The steam inlet closes and the exhaust vent opens venting the internal pressure within the pump body to atmosphere. The venting equalizes the internal pressure of the pump with external pressure allowing gravity flow of condensate to resume into the pump body. The fill/pump cycle repeats.