GB2175371A

GB2175371A - Backsiphonage stop valves

Info

Publication number: GB2175371A
Application number: GB8510250A
Authority: GB
Inventors: Albert Fletcher Wigley
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-02-07
Filing date: 1985-04-23
Publication date: 1986-11-26
Also published as: GB8510250D0; GB8503057D0

Abstract

A backsiphonage stop valve with individual non-return and anti-vacuum valve unit assemblies 22 and 16 integrated within the body 12 of the valve for preventing backsiphonage and backflow into drinking and domestic water supplies and for installing in any orientation into fluid flow lines. The preferred non-return and anti-vacuum valves are self operating without springs, they are retractable and renewable and with the stop valve closed during a fully pressurised flow in the pipe line the anti- vacuum valve can be removed and tested and the efficacy of the non-return valve verified before the anti- vacuum valve is returned to the body. <IMAGE>

Description

SPECIFICATION Improvements in or relating to fluid control valves BACKSIPHONAGE STOP VALVES This invention relates to an in-line stop valve with an integrated non-return valve and an anti-vacuum valve for the prevention of backflow and backsiphonage into a drinking and domestic water supply and referred to hereinafter as a backsiphonage stop valve designed for inclusion into an existing or new fluid flow line in any orientation on a central axis without distorting the linear flow of the pipe line.

The preferred protective devices against backsiphonage are individual self operating non-return and anti-vacuum valve unit assemblies without springs that are retractable from the body of the valve, replaceable and renewable. When the stop valve is closed or shut down for repair or testing purposes during a fully pressurised fluid flow condition in the pipe line the anti-vacuum valve unit can be extracted from the combined unit, examined, replaced or renewed. During this operation with the anti-vacuum valve unit removed the efficacy of the non-return valve can be verified before the anti-vacuum valve unit is returned and secured in the valve body.

Water Authority Requirements based on the New Model Water Bye-Laws 1985-6 require that drinking and domestic water supplies shall be protected against contamination by backsiphonage or backflow at all points of use and in particular the public water supply. The first category of protection concerns air gaps and non-mechanical devices. The second category of protection deals with combined non-return and anti-vacuum valves and it is in this category that the present invention fulfils the necessary requirements. It can be installed as the primary stop valve in a consumer's premises preventing backsiphonage into the public water mains (whole installation): it can also be installed as a service stop valve with protective devices to fittings and fitments connected to a water supply, thus providing for two distinct and separate functions.This combination of stop valve and protective devices in one unit reduces the costs that would be involved in assembling the necessary protective individual units with a stop valve.

Self-operating anti-vacuum devices invariably have to be installed in a horizontal or vertical position according to manufacturer's instructions and this often creates installation difficulties. One of the features of this invention, apart from the integrated stop valve, is that it can be installed in any orientation and in any flow direction of the pipe line. It is an allpurpose device for preventing backsiphonage and controlling water supplies.

According to the present invention the backsiphonage stop valve has a body with a valve seat, a supply pipe inlet with a screwed end for a pipe connection or compression joint, an aperture to receive a standard type stop valve headwork with washer plates and valve washer, a chamber to receive preferably an individual anti-vacuum valve assembly unit and air inlet cap and an outlet spigot to receive a valve casing containing preferably an individual non-return valve assembly unit, the valve casing terminates in an outlet with a screwed end for a pipe connection or compression joint.

When the stop valve headwork and valve unit is secured within the body aperture above the valve seating, the anti-vacuum valve unit secured within the valve chamber by means of a threaded air inlet cap and the non-return valve contained within the valve casing is screwed on to the outlet spigot of the valve body and all connections made water tight, the backsiphonage stop valve can be installed in a water supply pipe line and will function in the following manner:- with the stop valve open and pressurised water flowing through the combined unit the anti-vacuum valve will be closed and the non-return valve open.

When a minus pressure or vacuum occurs in the pipe line at the inlet of the combined unit the non-return valve closes and retains the water in the installation, the anti-vacuum valve opens and air is drawn through the apertures of the air inlet cap into the supply pipe and reduces the vacuum or minus pressure. When the water pressure is restored in the supply pipe the anti-vacuum valve and the non-return valve return to their original position and always act in sequence when such occasions occur. According to Water Authority Requirements the combined valves must be installed in a visible and accessible position with the anti-vacuum valve on the upstream or inlet side of the non-return valve.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 shows a lateral cross-section in the vertical position of an assembled backsiphonage stop valve with the combined valves operating in the fluid flow condition.

Figure 2 illustrates in a longitudinal section an exploded view of the individual parts of the valve before assembly. Referring to the drawing Fig. 1. the Backsiphonage stop valve in the open position with arrows 10 indicating the flow of water through the valve from inlet to outlet. The union joint 11 is for receiving a standard size tube with a compression joint ring 1 1a. A body 12 with an inlet and outlet and apertures or casings for receiving individual valve units has a valve seating 13. The valve washer 14 attached to the headwork 15 is in the open position above the valve seating 13. The headwork 15 is a standard type removable headwork of a 1010 stop valve. A cuplike anti-vacuum valve 16 made from elas tomeric material is in the closed position and secured to an oscillating member 16a, both parts contained within a retractable valve unit 16b.The valve unit 1 6b is secured and made watertight within the body casing 18 by means of a threaded connection on the valve retention and air inlet cap 17 with air inlet apertures 17a. An "0" ring 17b is compressed between the anti-vacuum unit and the body casing 18. The body 12 has a chamber or aperture 19 with a threaded spigot 20 for receiving the headwork of a non-return valve 21 which is shown in its deformed configuration but occurs when water is flowing through the valve. The valve 21 is secured to an operating member 21a which oscillates according to pressure or minus pressure in a retractable valve unit 22.The valve unit 22 with a flange compressed between the body spigot 19 with external thread 20 and an outlet casing with internal thread 23 is made watertight by the pressure produced by the tightening process between the threads on the body 19 and the valve casing 23.

Fig. 2. is an exploded view of the backsiphonage stop valve's individual parts before assembly, with the anti-vacuum and non-return valve shown as if operating under flow conditions. The direction of the flow of water is shown by the inlet and outlet arrows 10-compression union nut 11-compressing ring 11 valve body 12-valve seating 13-valve washer 14-1010 stop valve headwork 15-elastomeric anti-vacuum valve 16-oscillating valve member 1 6a-retractable valve unit 16air inlet cap with internal thread 17-air inlet apertures 17a-"0" sealing ring 17b-anti-vacuum chamber with spigot thread 18-non-return valve chamber 19-threaded spigot 20-deformable non-return valve 21-oscillating member 21 a-retractable valve unit 22-outlet casing 23-compression ring 1 la-compression unit nut 11-outlet arrow 10.

Claims

1. A backsiphonage stop valve for preventing backsiphonage or backflow into a drinking or domestic water supply comprising a stop valve body with a valve seat, a supply pipe inlet with a screwed end for a pipe connection or compression joint, an aperture to receive a standard type 1010 stop valve headwork with washer plate and valve unit, a chamber to receive preferably an individual anti-vacuum valve assembly unit and air inlet cap and an outlet spigot to receive a valve casing containing preferably an individual non-return valve assembly unit, the valve casing terminating in an outlet with a screwed end for a pipe connection or compression joint.

2. A backsiphonage stop valve as claimed in Claim 1, wherein the various parts are assembled with the 1010 stop valve headwork and valve unit secured in the body aperture above the valve seating, the preferred antivacuum valve unit assembly secured within the valve chamber by means of a threaded air inlet cap and the valve casing containing a preferred non-return valve assembly unit is screwed on to the outlet spigot of the stop valve body and with all connections made watertight, the complete backsiphonage stop valve unit can be installed in a water supply pipe line in ay orientation without distorting the linear flow of the pipe line.

3. A backsiphonage stop valve as claimed in Claims 1 and 2 wherein the preferred devices for preventing backsiphonage are individual self operating anti-vacuum and non return valve units without springs that are retractable, replaceable and renewable.

4. A backsiphonage stop valve as claimed in any of the proceeding claims wherein the stop valve can be closed or shut down for testing or repair purposes during a fully pressurised flow in the pipe line, the anti-vacuum valve unit removed, inspected replaced or renewed and the efficacy of the non return valve verified during this operation before the anti-vacuum valve is returned and secured in the valve body and the stop valve re-opened.

5. A backsiphonage stop valve as claimed in any of the preceding Claims wherein the combined unit can be installed as the primary stop valve in a consumer's premises (whole installation) providing the required protection against backsiphonage into public water mains.

6. A backsiphonage stop valve as claimed in any of the preceding Claims wherein the combined unit can be installed as a service stop valve with protective devices against backsiphonage to water using fittings and fitments, a requirement for "protection at points of use".

7. A backsiphonage stop valve as claimed in any of the preceding Claims wherein the combined unit can be installed into an existing or new fluid flow pipe line in any orientation, in any direction of flow and the efficacy of the protective devices tested in any position of installation providing it is installed to Water Authority Requirements "in an accessible and visible position".

8. A backsiphonage stop valve substantially as described herein with references to Figs. 1 and 2 of the accompanying drawing.