GB2281598A - Stopcock adaptor - Google Patents

Abstract

An adaptor (1) for mounting in a conventional stopcock body (2), after the normal headwork has been removed, a water meter or other device includes an inlet tube (8) which, in use, forms a fluid-tight seal with the seat (13) in the stopcock body (2). The inlet tube (8) is formed with an annular corrugation (10) whereby it is axially compressible and may thereby shorten in length upon the adaptor (1) being screwed to tightness into the stopcock body (2). The axial compressibility of the inlet tube (8) renders a given size of adaptor (1) suitable for use with any correspondingly sized stopcock body regardless of variations in the depth of the seat (13) within the body (2). <IMAGE>

Description

Water Fittings This invention relates to water fittings and more particularly to adaptors for mounting on a conventional stopcock body, after the head work has been removed, a water meter or other device such as, for example, a pressure regulator, filter or descaler. Hereinafter, such adaptors are referred to as "adaptors of the type described".

Adaptors of the type described of various designs have already been proposed and examples are described in, amongst others, British patent specification No 2 251 904A. A feature common to all the designs is an inlet tube (see reference numeral 12 in the drawings of that specification) the lower end of which forms a fluid-tight seal with the valve seat of the stopcock body when the adaptor is screw-threadedly mounted in the body. Whilst not all of the embodiments described in the aforementioned specification show separate sealing means for affording that fluid tight seal, it would be readily apparent to those skilled in the art that such sealing means would normally be required and that this would preferably comprise, for example, (as is shown in Fig 5 of the above specification) a resilient annular washer that is compressed, and forms a seal, between the lower end of the inlet tube and the valve seat when the adaptor is in place; in other words, the inlet tube and washer co-operate with the valve seat of the body in much the same way as does the head work valve closure of the stopcock when used as such and in its closed ("off") position. However, we have recognised that such an arrangement would give rise to the problem that one and the same adaptor would not be suitable for use with all available stopcock bodies of a given size because the depth of location of the valve seat within the body tends to vary somewhat, sometimes by as much as about 6 mm, from one manufacturer to another.

It is an object of the invention to solve this problem whereby a given size of adaptor of the type described may universally be employed with virtually any correspondingly sized stopcock body after the headwork has been removed (the sizing referred to being the diameter of the interengageable threaded portions of the adaptor and stopcock body respectively).

According to the present invention, therefore, an adaptor of the type described is characterised in that the inlet tube is axially compressible and may thereby shorten in length upon the adaptor being engaged to tightness with the stopcock body.

Axial compressibility of the inlet tube may be afforded in a number of ways. For example, the inlet tube, rather than as hitherto proposed being a rigid length of tube, may be a wholly corrugated tube of known type capable of being axially compressed.

Preferably, however, the inlet tube is a generally rigid tube of, for example, copper or suitable copper alloy, the wall of which is locally deformed to provide one or more, for example a pair of, annular corrugations which may axially deform wholly or partially under the axial load imparted to the tube as the adaptor is engaged to tightness with the stopcock body.

Thus, by providing an adaptor of the type described with an axially compressible inlet tube having an original length equal to, or preferably slightly greater than, the length required to form an adequate fluid-tight seal with stopcock bodies having the maximum valve seat depth likely to be encountered in practice, the adaptor will be suitable for use not only with such bodies but also with like-sized bodies having a lesser valve seat depth. As noted earlier, there could be a variation in that depth of up to about 6 mm and so the inlet tube should preferably be axially compressible by at least that amount.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIG 1 is a sectional side elevation, to actual size, of an adaptor constructed in accordance with the invention assembled with a conventional i" stopcock body; FIG 2 is a similar view to that of Fig 1 but showing the same adaptor assembled with a different i" stopcock body; and FIG 3 is a sectional side elevation of an alternative form of adaptor inlet tube.

Referring firstly to Fig 1, the adaptor designated generally 1 is shown assembled with a "standard" stopcock body 2 after removal therefrom of the usual headwork. As will be known to those familiar with UK water fittings, stopcock bodies are commonly available in two standard sizes, namely a inch' size and a 'i inch' size, the dimensions referring to the diameter of the valve seat aperture.

Generally, " bodies have a standard, approximately 24 mm/18 thread per inch (TPI) female-threaded port for receiving the headwork and i" bodies have a standard, approximately 31 mm/18 TPI female threaded port for the headwork. However, as between " bodies produced by different manufacturers, and also i" bodies, the depth of location of the valve seat varies considerably, often as much as 6 mm from one manufacturer to another. The present invention is concerned with means whereby a given adaptor of the type described may be used with any " stopcock body, and another with any " stopcock body, regardless of the variations of valve seat depth. Thus, it is necessary to produce and stock only two standard sizes of adaptor, one for " stopcock bodies and one for t" bodies, with all the advantages that that has, although naturally further sizes may be produced to fit body sizes other than " or ".

The adaptor 1 comprises an externally cylindrical body made in two parts, namely a lower part 3a and an upper part 3b. The lower part 3a has integrally formed with it a male-threaded boss 4 for engagement with the correspondingly female-threaded port 5 of the stopcock body 2. As noted earlier, the boss 4 will have an external diameter either of about 24 mm with 18 threads per inch or of about 31 mm with 18 threads per inch for use with " and i" stopcock bodies respectively.

The lower part 3a is further formed internally with an inlet passageway 6 and an outlet passageway 7 which extend generally vertically therethrough in side-by-side relationship. The lower end of the inlet passageway 6 terminates in a circular bore which receives the upper end portion of a relatively thin-walled copper inlet tube 8 with which a fluid-tight seal is made by means of an 0-ring 9.

Insertion of the upper end portion of the tube 8 into that bore is limited by an outwardly extending, annular corrugation 10 formed in the wall of the tube 8. An annular outlet passageway 7', which communicates with the passageway 7, is defined between the internal surface of the boss 4 and the external surface of the tube 8 which extends coaxially within, and below, the boss 4.

The lower end of the tube 8 has sealingly secured to it an annular ferrule 11 that retains an 0-ring seal 12 for co-operation with the valve seat 13 of the stopcock body 2.

The inlet passageway 6 houses a ball valve 14 of conventional type that is manually actuable by a lever 15 to close or open the passageway 6.

The outlet passageway 7 houses a non-return ("check") valve 16, again of conventional type, whereby backflow of water from the outlet (consumer) side of the installation into the inlet (water authority main) side is prevented.

The upper part 3b of the adaptor 1 is sealingly secured to the lower part 3a by bolts (not shown) and is internally configured to extend the inlet and outlet passageways 6, 7 upwardly in such a way that they will be in register with, respectively, the inlet and outlet ports of a standard water meter (not shown) sealingly engaged, in use, by female threads 17 formed in the upper end of body part 3b of the adaptor 1.

In Fig 1, the adaptor 1 is shown assembled with a " stopcock body 2 having more or less the maximum dimension A likely to be encountered in practice. Assembly is carried out simply by screwing the boss 4 into the standard threaded port 5 of the stopcock body 2 until the ferrule 11 with its seal 12 sealingly engages the seat 13. The boss 4 is then further screwed up, to tightness, during which the corrugation 10 is slightly squashed. Because the dimension A is relatively large, only slight axial compression of the corrugation 10 occurs. A fluid tight seal between the boss 4 and the port 5 is ensured by a washer 18.

However, in the " stopcock body shown in Fig 2, the dimension A' is a few millimetres less than dimension A in Fig 1 and, upon assembly of the adaptor 1 with the body 2, the corrugation 10 becomes more or less fully axially compressed as shown at 10'.

The degree of axial compressibility of the tube 8 may be varied by varying the depth of the corrugation 10 and/or by providing more than one such corrugation. For example, in Fig 3 there is shown a tube 8 having a pair of corrugations 10 and 10" whereby, other things being equal, a larger degree of compression is possible thereby catering for a greater variation in the dimension A as between i" stopcocks produced by different manufacturers.

Naturally, the or each corrugation 10, 10" should be capable of being axially compressed during assembly of the adaptor 1 with the stopcock body 2, the final tightening of which may be effected using a spanner; to that end, a suitable wall thickness of the tube 8,as well as a suitable profile for the corrugation(s), may be established by simple experiment.

In use, when there is a demand for water, water enters the stopcock body 2 from the mains supply, as indicated by the arrow "IN", flows through the tube 8 via the stopcock body seat 13, through the passageway 6 via the ball valve 14 and then into the water meter via the upper body portion 3b of the adaptor 1. The water then flows out of the meter or other device into the passageway 7, via the body portion 3b and the non-return valve 16, then into the annular passageway 7' and thence to the point of use via the outlet of the stopcock body 2 ("OUT").

If, during service, it becomes necessary to service the meter (or to turn off the mains water supply to the premises in question), the ball-valve is simply turned off by means of the handle 15 and backflow from the outlet side is prevented by the check valve 16. The latter valve generally prevents backflow and thus possible contamination of the mains water supply.

As indicated above, an adaptor of the invention may be used to mount an alternative device such as, for example, a pressure regulator, filter or descaler for which purpose the upper part 3b of the adaptor illustrated in the drawings may, of course, require internal modification of the diameter and/or pitch of the threads 17 and/or of the configuration of the inlet/outlet passageways formed therein in order to be compatible with such device.

Claims (7)

1. A stopcock body adaptor of the type described including an inlet tube the lower end of which forms, in use, a fluid-tight seal with the seat of the stopcock body, characterised in that the inlet tube is axially compressible and may thereby shorten in length upon the adaptor being engaged to tightness with the stopcock body.

2. An adaptor according to claim 1 wherein the inlet tube is annularly or helically corrugated substantially throughout its entire length so as to render it axially compressible as aforesaid.

3. An adaptor according to claim 1 wherein the inlet tube is a plain tube formed with one or more annular corrugations so as to render it axially compressible as aforesaid.

4. An adaptor according to claim 3 wherein the or each annular corrugation extends radially outwards beyond the plain outer surface of said tube.

5. An adaptor according to any one of claims 1 to 4 wherein the inlet tube is of copper or a copper alloy.

6. An adaptor of the type described including an inlet tube substantially as hereinbefore described with reference to, and as illustrated in, Figure 1 and Figure 2 or Figure 3 of the accompanying drawings.

7. An adaptor of the type described substantially as hereinbefore described with reference to, and as illustrated in, Figure 1 or Figures 1 and 3 of the accompanying drawings.