With roots dating back to the early 1900's, the Henry Pratt Company designs, develops, manufactures and markets control systems. Our products are used in potable water, wastewater, power, industrial, and nuclear markets. Pratt's control systems include the Check-Mate, the Electro-Check, a High Pressure Accumulator System, a Low Pressure Accumulator System and a Back Up Power Supply System
CHECK MATE DETAILS OF OPERATION
Normal Pump Start
In this mode, the pump motor circuit is energized, thereby starting the pump. As the pump comes up to speed, or design head, three basic methods are used to signal the Pratt pump check valve.
Single Pressure Switch – The pressure switch is tapped off the upstream side of the pump check valve. When the discharge pressure of the pump reaches a level greater than the downstream system head, the pressure switch trips, energizing the solenoid circuit to the four-way valve, opening the pump check valve.
Time Delay Relay – This electrical device is part of the pumpmotor circuit. When the pump motor circuit is energized, the time delay relay is energized, preset to energize the four-way valve circuit, causing the Pratt pump check valve to open. The amount of time delay is related to the type of pump and the time it takes for the pump to come up to speed.
Differential Pressure Switch – This pressure switch is tapped off the downstream and upstream sides of the Pratt pump check valve. When the pump/motor circuit is energized, the differential pressure switch senses when the pump discharge pressure is greater than the downstream pressure, trips, closing the four-way valve circuit and causing the Pratt pump check valve to open. During pump start, the two-way solenoid valves are continuously energized when the pump is on line.