Pump Control Valves
The laws of physics dictate that any change in the fluid’s velocity produces a corresponding change in the fluid’s pressure. Pressures changes produced by a velocity change are called surge pressures. Surge pressures are intensified by sudden velocity changes and minimized by gradual changes.
“Pump Control Valve” is the generic name for an automatic valve installed on the discharge of a pump and used to minimize the pressure surges associated with the starting and stopping of pumps. The pump control valve is hydraulically or electrically actuated and its operation is sequenced with that of the pump motor.
In the usual operating sequence, the pump starts against a closed valve which opens at a controlled speed only after the pump is up to operating pressure thereby gradually increasing the fluid velocity from rest to design conditions. Start-up surge pressures are minimized.
At pump shutdown, the pump control valve slowly closes as the pump continues to run. The closing valve gradually brings the fluid to rest thus preventing excessive pressure surges. The pump motor switches off only after the valve is closed so that all “normal” pump shutdowns without excessive pressure surges.
All pump control valves should incorporate an integral check feature and/or an “emergency” closing feature to close the valve upon power outage, pump or motor failure or any “uncontrolled” stoppage of pumping to prevent excessive reverse flow and pump backspin. Although pump control valves minimize surges during a normal pump shutdown, “emergency” shutdowns usually result in a pump control valve closure that is faster than normal. Installing a GA Industries’ surge relief valve or surge anticipator valve can protect the pump station from an excessive pressure rise subsequent to these emergency events.
GA Industries offers three basic types of pump control valves suitable for water, wastewater and sewage pumping:
Electric Check Valves
AWWA Ball Valves
CHECKtronic© Pump Control Valves
All pump control valves require electrical logic to sequence the operation of the valve with that of the pump motor. The GA Industries "Pump Director"
provides that logic in a standard “off-the-shelf” pre-wired electrical control panel to interface any of these GA Industries pump control valves with the pump motor controls.