In the pump stops, the valve closing process to complete its own weight

Check valve is an effective way to prevent fluid backflow prevent reverse impeller pump runaway protection device, it is widely used in industrial agricultural production. Currently used mostly for hanging flap check valve check valve, no external  Instrument needle valves . In the pump stops, the valve closing process to complete its own weight. It is characterized by simple, inexpensive, back flow is small. Its  2 way manifolds  off valve water hammer bigger. This is reflected in two aspects: one is a sudden when the pump stops, the valve began to move, when you close to a relatively small opening, the fluid backflow may occur, under the impact of the liquid in the back, there will be a sudden closure of the valve process, resulting in a direct water hammer.

Elaborated resistivity backflow prevention device backflow prevention performance

Currently on the market there have been some low resistance, energy-efficient new backflow prevention device. As its name with "low resistance", "backflow" This attractive words, but also in the popular and raise doubts and controversy, and continues not broken. The following will explain the dynamic hydraulic control point resistivity  Instrument needle valves  prevention backflow prevention device performance, given prior to analysis and recognition industry consensus standards. Consensus 1: backflow prevention device is defined as "a strictly limited water pressure in the pipeline only one-way flow of hydraulic control combination device." The so-called strict to prevent  Male connector shall include: ① can prevent all conditions occur  Check valve reflux; ② can prevent all conditions occur siphon reflux; ③ outlet end as long as the media back to the inlet side, are called backflow contamination. Consensus 2: backflow prevention device structure is characterized by a two-return unit and drain drainage device component. Therefore, any discharge drainage device does not include backflow prevention devices are not called backflow prevention device.