Back flow preventer

Abstract

Disclosed is a backflow preventer comprising a housing which is provided with an inlet port, an outlet port, and at least one leakage opening that is located between said ports. The housing accommodates two first check valves which are arranged one behind the other. The first check valve is movably retained for opening or blocking a flow connection between an intermediate space of the housing and the leakage opening. In order to prevent, in a simple structural manner, the pressure from unduly increasing in the area of the outlet port, the housing encompasses an inner housing and an outer housing. The outer housing is provided with the at least one leakage opening while the inner housing accommodates the two check valves and is retained within the outer housing so as to be movable in the direction of flow. Furthermore, the inner housing comprises an outlet port via which the flow connection between the intermediate space and the leakage opening can be established regardless of the position of the inner housing by displacing the first check valve.

Description

technical field [0001] The invention relates to a backflow preventer, in particular for connecting a high-pressure cleaner to a drinking water supply line, comprising a housing with an inlet, an outlet and at least one device arranged in the direction of flow between the inlet and the outlet. The leak hole, and accommodate a first and a second non-return element, they are arranged in sequence along the flow direction, wherein the first non-return valve is movably fixed to open or close a set of two non-return valves of the housing The flow connection between the intermediate cavity and the leak hole. Background technique [0002] Such a backflow preventer is also known as a "line interrupter" and is known from laid-open document DE 2424978 A1. They are used in washing machines, especially high pressure washers or washing machines. If such a washing machine is connected to a drinking water supply line, it must be ensured that contaminated washing liquid cannot flow back fro...

AI Technical Summary

Problems solved by technology

In this position, however, a rise in pressure in the outlet area of ​​the backflow preventer may cause damage to the backflow preventer or a cleaning machine connected to it.

This increase in pressure can occur, for example, briefly as a pressure spike in a high-pressure cleaner if the high-pressure cleaner is switched off

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