What Are Constant Pressure Valves?
A Constant Pressure Valve or CPV is a pump control valve that makes a variable flow pump out of any standard, constant speed pump. Attached to the discharge of the pump, a Constant Pressure Valve, automatically chokes back the output of a pump to match the users requirement for water. As the gallons per minute used decreases, the amount of electricity used by a centrifugal impeller naturally decreases without changing the speed of the pump.
The CPV maintains a constant pressure for the water user regardless of the amount of water being used. The CPV is completely mechanical requiring no electronics. Large pumps are now capable of very small flow rates without variable speed controls, huge pressure tanks, or water towers. Pumps equipped with a Constant Pressure Valve can operate safely from as low as 1 GPM to as much as the pump will produce.
The CPV can stop pump cycling, eliminate water hammer, extend pump life, and save electricity. The CPV can hold a steady level in elevated tanks and water towers or can deliver water to a city of 40,000 people from a tank as small as 44 gallons.
The Constant Pressure Valve or CPV is new technology that replaces variable speed pumps, water towers, and large hydro tanks. Recent advances in variable speed pumps have made them smaller and less expensive. Problems such as noise, vibration, voltage spikes, wire lengths, low flow cycling, and pressure spikes have not been solved since variable speed pumps were introduced decades ago. Problems with water towers and large hydro tanks have always been well known. Constant Pressure Valves eliminate these problems, are just as energy efficient, and give excellent variable flow performance without the problems associated with changing the speed of the pump.
There are many types of Constant Pressure Valves. The only non closing type CPV is a Cycle Stop Valve which can be maintenance and problem free. Cycle Stop Valves do not have screens, bypass holes or tubes, needle valves, and other controls that will cause problems in real world applications. Simple mechanical valves are a reliable way to get variable flow pump performance from any standard constant speed pump.