Pressure reducing type anti-backflow check valve

Abstract

The invention discloses a pressure reducing backflow-preventing check valve. The pressure reducing backflow-preventing check valve comprises a valve seat, a valve clack, a rocker and double torsional springs. One side of the valve clack is hinged to the upper end of the valve seat while a roller is mounted at the other side; one end of the rocker is a fixed end while the other end is a free end, and the fixed end of the rocker is connected to the lower end of the valve seat through a pin roll; the roller leans against the rocker and slides between the fixed end of the rocker and the free end of the rocker; two limiting hanging hooks are arranged at the lower end of the valve seat; the double torsional springs are arranged on the pin roll in a sleeving manner and are symmetrically arranged on two sides of the rocker left and right, middle torsion beams of the double torsional springs are limited by the rocker, and the two torsion beams which extend left and right of the two torsional springs are limited by the limiting hanging hooks at the lower end of the valve seat; and the spring forces of the double torsional springs act on the rocker, so that the valve clack is in a normally closed state, and the roller on the valve clack rolls on the rocker by virtue of an external force to open the valve clack. As a result of a structure of the double torsional springs and the rocker, the check valve achieves a better backflow-preventing effect.

Description

technical field [0001] The invention relates to the technical field of pipeline valves, in particular to a decompression type anti-backflow check valve. Background technique [0002] The backflow preventer is used in pipelines such as sewage treatment to prevent backflow pollution caused by the backflow of liquid in the flow direction. The backflow preventer is a valve device composed of two separated check valves and a safety drain valve. The structure of the existing check valve is too simple, and the resistance to the water flow is very obvious. The resistance of the check valve to water flow increases linearly with the increase of the opening of the disc, and when the pressure chambers of the backflow preventer produce small pressure fluctuations, the safety drain valve frequently discharges water. [0003] In addition, the valve seats of domestic check valves are basically made of metal, and the fixed connection between parts must adopt traditional mechanical connecti...

AI Technical Summary

Problems solved by technology

[0003] In addition, the valve seats of domestic check valves are basically made of metal, and the fixed connection between parts must adopt traditional mechanical connections, such as threaded connections. The valve seat must be drilled and tapped, and then Each component is fixedly installed in the valve seat through threaded connection, which consumes time and materials

Moreover, during the opening and closing process of the check valve, the components and the valve seat vibrate repeatedly, and the components are prone to loosening

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