41results about How to "Improve one-time assembly pass rate" patented technology

The invention provides a pressure reduction type backflow preventing device. According to an existing backflow preventing device, a pressure reduction portion adopts a membrane for transferring pressure and is sealed, however, due to the fact that a processing technique of the membrane is complex, the product quality is unstable, and the service life is influenced. The pressure reduction type backflow preventing device is composed of two check valves which work independently. A differential pressure relief valve is externally connected between the two check valves. The two ends of each check valve are further directly connected with two ball valves used for maintenance and four elastic sealed test ball valves, and therefore the complete pressure reduction type backflow preventing device is formed. Under the water supply condition, water in a main water delivery pipeline passes through a pressure reduction area from the check valve in the inlet position, reaches the outlet of the check valve in the outlet position, and is supplied to users. High-pressure water at the inlet of the check valve in the inlet position is directly led into an upper membrane cavity of a pressure reduction valve, and a lower membrane cavity communicates with the inlet of the check valve in the outlet position. Due to the fact that a certain pressure difference exists, a membrane is pushed to move rightwards, the pressure reduction valve is closed, and water supply is normal.