Flowserve FPS 14 - Manual (Page 2)

Operation
Maximum operating pressure: 150 psig
1. At the beginning of the cycle, the float ball
(4.2) is at its lowest position. The vent
valve (4.4) is open and the pressure valve
(4.3) is closed.
2. The liquid to be pumped enters the pump
tank by gravity through the inlet check
valve. As the pump fills, the float ball (4.2)
rises. The outlet check valve prevents back
flow of liquid into the pump tank from the
downstream side.
3. At the high trip point the mechanism
snaps over center. The compressed coil
spring (4.5) simultaneously closes the vent
valve (4.4) and opens the pressure valve (4.3). The motive gas flows through the pressure valve
(4.3) and pushes the liquid out of the pump tank though the outlet check valve. The inlet check
valve prevents liquid from flowing back into the upstream piping.
4. As the liquid falls, the float ball (4.2) drops. At the low trip point, the mechanism snaps over
center and the compressed coil spring (4.5) simultaneously opens the vent valve (4.4) and
closes the pressure valve (4.3). The pump tank depressurizes as the motive gas is relieved
through the vent valve.
5. After the pressure in the pump tank is relieved through the
vent valve (4.4), flow resumes through the inlet check valve
and a new cycle begins.