Pressure reduction type backflow preventing device

Abstract

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.

Description

Technical field: [0001] The invention relates to a decompression type backflow preventer. Background technique: [0002] The decompression backflow preventer (hereinafter referred to as the backflow preventer), as a valve component that can effectively prevent the dirty water in the branch circuit from flowing back to the main road, is widely used in developed countries such as Europe and the United States. In China, common check valves are mainly used to prevent water backflow, and there are not many applications of backflow preventers. The currently used backflow preventer uses a diaphragm to transmit pressure and seal the decompression part, but due to the complicated processing technology of the diaphragm, the product quality is unstable, which affects the life of the backflow preventer. In addition, due to the reaction force of the diaphragm, it will have a certain impact on the accuracy of the design of the spring force at the decompression part, and affect the firs...

AI Technical Summary

Problems solved by technology

The currently used backflow preventer uses a diaphragm to transmit pressure and seal the decompression part. However, due to the complicated processing technology of the diaphragm, the product quality is unstable, which affects the life of the backflow preventer.

In addition, due to the reaction force of the diaphragm, it will have a certain impact on the accuracy of the design of the spring force at the decompression part, and affect the first-time assembly pass rate of the product.

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