Pump Discharge Butterfly Valves

Pump discharge valve for the large pumping schemes is a cost effective solution to an otherwise option of utilizing an isolating valve and a non return valve on the pump outlet.

Owing to its butterfly type of construction, the pump discharge valve has high flow capacity and low head loss (i.e. pressure drop) which would reduce the pumping energy substantially on a continuous basis.

Hailed as a major breakthrough in modern pumping design , the butterfly type pump discharge valve has made inroads into modern thermal power stations, nuclear power stations, lift irrigation projects, metro water supply schemes etc., which are the largest consumer of centrifugal pumps.

Advantages of Pump Discharge Butterfly Valves

Dual Speed Closing Time : 90% of the valve closure will take 10% of the time and 10% of the remaining travel will take 90% of the time, hence best suitable on an operating system.

Pressure drop : In Conventional Pumping system head loss coefficient of reflux valve is 0.6 and for isolating valve is 0.15, while in case of Pump Discharge it is 0.15

Requirements of Pump Discharge Butterfly Valves

• Replaces two valves, i.e., check valve and guard valve.
• Rubber Seated 100% leak proof.
• High flexibility in adjusting opening and closing time at site.
• Start the pump as per pump characteristics demand – Crack open, close valve partially or full before pump stops.
• To isolate pump for maintenance.
• To provide tight shut-off sealing in direction opposite to normal flow and to permit other pumps running without affecting flow from running pumps.

Advantages of Pump Discharge Butterfly Valves

• Will not exhibit flow induced flutter of blade.
• Valves can be ebonite lined for resistance to corrosion / long life.
• Common power unit can be provided for gang of valves limiting space and operational conveniences.
• With crack opening feature provided in Pump discharge valves pump starting currents will be substantially lower. Accordingly switch gear designs of pumps will be economical.
• By providing double seal arrangement on the pump discharge valve, seal replacement possible with other pumps in service.

Operation Philosophy

• When pump starts the hydraulic oil is fed into the head end of the cylinder and the valve crack opens.
• Once the pumps picks-up full speed / down stream filled-up, valve fully opens (time to full open after crack opening can be adjusted).
• Valve can be closed before the pump stops / pump trip. Valves closes due to counter weight without any external power.
• Valve closing time 90% fast and 10% slow. This is achieved by cushioning provided in the cylinder and therefore avoiding slam shut-off.
• Opening and Closing time can be controlled.
• Hydraulic system provided with accumulators to facilitate opening of the valve in case of electrical power failure.
• The operation philosophy is more reliable than automatic self operated reflux valves.