Mark Strijack is a customer support manager at Singer Valve. For more information, visit singervalve.com.
These valves can alleviate a variety of pump system issues.
The source of surging is most commonly initiated by the routine starting and stopping of pumps within a pump system. Minimizing the system surges on pump start and stop cycles can vastly improve the health of a pump system by using inline or bypass pump control valves, which slowly open and close to gradually increase or decrease flow into the mainline.
Booster Pump (Inline) Control
Booster pump control (BPC) valves are located in line, downstream of the pump. When started, the pumps start against a closed valve. The solenoid is then energized, opening the BPC. At pump shutdown, the solenoid valve is de-energized by the system control to put the valve into closing mode.
Image 5. Booster pump inline control valves, installation schematic
There is an electronic limit switch on the stem of the BPC, so when the valve is almost fully closed, a signal goes back to the pump control panel to shut the pump down. The opening and closing speeds are adjustable. This is a very efficient way to manage pump control and does not require any static pressure in the piping system downstream. When sizing BPC valves, consultants often prefer to oversize the valves to minimize pressure loss through the valves.
The dilemma is that when selecting pumps, efficiency is always a concern. When a BPC valve is used, if sized too small, pressure loss or lack of efficiency may be affected.
Deep Well (Bypass) Pump Control
If site conditions permit, deep well (DW) pump control valve solutions can be a very economical and practical solution to pump control. This type of valve requires some static pressure downstream to work effectively. Elevations are the best method to ensure the static condition, which should be a minimum of 100 feet. This static pressure applies pressure to an inline check valve until pump pressure overcomes this check valve and allows flow into the distribution pipe.
Image 6. DW pump control valves and installation schematic
The pump starts against a fully open DW valve. This valve is located off a tee and discharges to atmosphere. When the pump starts, a signal is sent to the solenoid on the DW valve, which starts the closing process of the valve. The speed of closure can be selected by adjustments to the manual needle valve. As the pressure builds in the manifold, it eventually overcomes the static pressure holding the check valve closed and water commences flowing to the system. At pump shut down, the solenoid on the DW valve is de-energized, which causes the valve to start opening. The opening speed can be manually adjusted using the needle valves.
When the valve is almost fully open, a limit switch, mounted on the stem of the DW valve, sends a signal to the pump control panel to shut the pump down. If site conditions are correct, this can be a very efficient way of managing pump control for single-speed motors.