Gravity type backflow preventer

Abstract

The invention discloses a gravity type backflow preventer, which is applied to a place where pressure water in a pipeline is strictly limited to flow in one way. The gravity type backflow preventer mainly comprises a main valve (1), a pressure difference water escape valve (2) and a gravity water escape valve (3), wherein the main valve (1) mainly comprises valve bodies (1-1 and 1-2), a positioning board (1-3), a sliding sleeve (1-6) and lifting type check valve plates (1-7 and 1-8); the pressure difference water escape valve (2) mainly comprises a valve body (2-1), a valve cover (2-2), a weight (2-3), a flexible membrane (2-4) and a lifting type valve plate (2-6); and the gravity water escape valve (3) mainly comprises a valve body (3-1), a valve cover (3-2), a weight (3-3), a flexible membrane (3-4) and a lifting type valve plate (3-6). Compared with the prior art, the gravity type backflow preventer has the outstanding advantages that: water flow resistance is extremely low; and the total loss of head is reduced from over 0.05MPa to below 0.005MPa.

Description

technical field [0001] The invention relates to a backflow preventer, in particular to a gravity backflow preventer used in places where pressure water in pipelines can only flow in one direction. Background technique [0002] Backflow preventers are widely used in municipal water supply pipe networks to prevent backflow water generated by users from entering the pipe network again, avoid pollution accidents, and ensure hygienic and safe water supply. According to the requirements of the specification, isolation measures such as backflow preventers should be installed at the points where the municipal pipe network connects with users, and the diversion points of different systems and different water quality. However, the use of backflow preventers leads to the following problems that cannot be ignored: The loss is generally above 0.05MPa, even reaching 0.1MPa. The current annual water supply of the municipal water supply network in my country is not less than 50 billion m 3 ...

AI Technical Summary

Problems solved by technology

According to the requirements of the specification, isolation measures such as backflow preventers should be installed at the points where the municipal pipe network connects with users, and the diversion points of different systems and different water quality. However, the use of backflow preventers leads to the following problems that cannot be ignored: The loss is generally above 0.05MPa, even reaching 0.1MPa. The current annual water supply of the municipal water supply network in my country is not less than 50 billion m 3 , if all flow through the backflow preventer, according to the head loss of 0.05MPa, per m 3 According to the empirical calculation of water consumption of 25W, the total annual power consumption is more than 1.25 billion kw.h, which causes huge waste and significantly increases the operating cost of water supply enterprises.

[0003] At present, the disadvantage of large resistance and high energy consumption of backflow preventers at home and abroad is caused by structural defects. The total head loss includes water flow turbulence loss and elastic resistance of elastic components, which is not easy to obtain by modifying the shape of the flow-passing parts. To reduce turbulent flow loss, it is impossible to eliminate or even reduce elastic resistance, so it is difficult to make technical improvements on the existing basis

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