Follow-up backflow preventer

Abstract

The invention discloses a follow-up backflow preventer which is a place used for strictly allowing pressure water in a pipeline to unidirectionally flow. The follow-up backflow preventer is mainly composed of a valve body (1), a gravity-type check valve I (2), a gravity-type check valve II (5) and a pressure difference drain valve (8), and the valve body (1) is mainly composed of a water incoming cavity (12), a valve cavity (13), a water outgoing cavity (14), a back pressure cavity I (15), a back pressure cavity II (16), a positive pressure cavity (17), a drain valve cavity (18) and a dewatering cavity (20). Compared with the prior art, the follow-up backflow preventer has the advantages that water flow resistance is greatly reduced, and waterhead loss is allowed to be lowered below 0.015Mpa from 0.1Mpa.

Description

technical field [0001] The invention relates to a backflow preventer, in particular to a low-resistance follow-up backflow preventer used in strictly limited 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, backflow preventers should be installed at the municipal pipe network and user access points, different systems and diversion points of different water quality, but the allowable head loss of the backflow preventer is generally above 0.05MPa or even 0.1MPa, which significantly increases the municipal The water supply and power consumption of the pipe network and the water leakage rate of the pipe network have caused a lot of waste. For the co...

AI Technical Summary

Problems solved by technology

The disadvantage of the existing backflow preventer is that it has high resistance and high energy consumption, which is mainly caused by the spring structure that establishes the stepped pressure difference. flow loss, and the elastic resistance increases with the increase of the flow rate. It can be seen from the process of its technological development that the standard implemented by the backflow preventer has developed from the urban construction industry standard (CJ / T160-2002) to the urban construction product industry standard (CJ / T160-2002) / T160-2010), to the national standard (GB / T25178-2010), and the recent mechanical industry standard (JB / T11151-2011), the purpose of which is not to improve safety performance, but to try to reduce head loss, but Due to the inheritance of the traditional spring structure, the drag reduction method basically relies on reducing the safety parameters, failing to eliminate the elastic resistance of the spring, allowing the head loss to remain at a high level above 0.06Mpa, the effect is not ideal, and the development process has also proved that in the existing It is difficult to improve and break through on the basis of technical ideas, and high resistance and high energy consumption have become the biggest defect of existing technologies

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