Patent ID: 7059340
Filing Date: 2006-06-13
Classification: E03C,Y10T

Abstract:
1. A pipe disconnector for separating a service water system from a drinking water system, the service water system being arranged to be filled or re-filled from said drinking water system, comprising: a pipe disconnector casing having inlet port means for connecting said casing to said drinking water system, outlet port means for connecting said casing to said service water system and drain passage means for connecting said casing to a drain, said casing defining a flow passage from said inlet port means to said outlet port means, said drain passage means branching off from said flow passage, upstream and downstream backflow preventer means in said flow passage, both backflow preventer means being arranged to permit water flow in said flow path from said inlet port means to said outlet port means and to block water flow from said outlet port means to said inlet port means, said casing defining a space in said flow passage between said upstream and downstream backflow preventer means, relief valve means located in said space between said upstream and downstream backflow preventer means, movable between an open position and a closed position and exposed through said upstream backflow preventer means to water pressure from said inlet port means, said water pressure acting to urge said relief valve means towards its closed position, wherein said upstream and downstream backflow preventer means and said relief valve means are combined to form a structural unit which is designed to be set in or removed, as a whole, into or from, respectively, said flow passage of said pipe disconnector casing, said relief valve means comprises a sleeve shaped slide valve body having a cylindrical peripheral surface and having an upstream end with an upstream end face and a downstream end with a downstream end face, said upstream end face being exposed through said upstream backflow preventer means to water pressure from said inlet port means, and said downstream end face being exposed to pressure in said space between said upstream and downstream backflow preventer means, said slide valve body is slidable in said flow passage between an open position and a closed position under the action of a pressure difference between said pressures in said inlet port means and said space, said slide valve body, in its closed position, covering said drain passage means, said pipe disconnector casing includes two spaced sealing rings retained therein and surrounding said flow passage, said slide valve body being guided, with said peripheral surface by said two sealing rings, said drain passage means being defined between said sealing rings; said upstream backflow preventer is mounted within said slide valve body, the pressure in the drinking water system required for opening the upstream backflow preventer means is larger than the pressure required for closing the relief valve, said downstream backflow preventer means comprises a jacket surrounding a backflow preventer check valve, said jacket having a downstream end and a flange with a circular array of recesses at said downstream end, said slide valve body, at its downstream end, has a circumferential array of axial, resilient fingers, which are guided in said recesses of said flange, and have inside lugs, said fingers being spring biased, whereby said lugs snap behind said flange, and a compression spring is supported on said flange and engages said slide valve body to generate a bias towards said open position.