GB2062811A - Ball float valve - Google Patents

Abstract

A piston (24) for a ball float valve, the piston having an undercut recess 28 for the reception of a resilient closure member. So that a new closure member can be fitted very easily in the recess 28, the latter is provided with a discontinuous flange 40 so that there are at least two diametrically opposite points at which the flange is broken whereby a new closure member can be inserted by folding it diametrically and feeding the opposite halves of the member into the recess through the mouth formed by the points where the flange is broken. <IMAGE>

Description

SPECIFICATION Ball float valve The invention relates to ball float valves and has for its object to provide an improvement therein.

Ball float valves have been known for many years and include a valve seat and a valve assembly slidably mounted in a valve chamber for movement towards and away from the valve seat to open and close the valve in accordance with movements of a float. Such valves are commonly used in flushing cisterns and other water tanks for controlling the water inlet to admit water when the level in the tank falls below a pre-determined level. One type of valve of this kind, commonly referred to as the "Portsmouth" type (for example, described in B.S.S. 1212: Part 1 comprises) a housing having a chamber in which is axially slidable a piston having a resilient valve closure member at one end to engage an inlet valve seat at the end of the chamber. The piston is engaged by the heel of a lever pivoted to the housing and carrying a float at its other end.Upward movement of the float urges the piston towards the valve seat and the float mounting is so arranged that when the float is at the maximum desired water level the closure member is forced against the valve seat. When the level falls the float drops with it and moves the piston away from the valve seat so that water is admitted to the cistern or tank in which the valve is fitted.

A ball float valve, for example a ball flat valve of the "Portsmouth" type, is very simple and reliable and for this reason is ideally suited for use in a domestic water supply system. However, the resilient valve closure member with which the piston is provided eventually, after long use, becomes worn so that the valve no longer closes effectively and the closure member needs to be renewed, often by a person of limited skill and with a minimum of tools at his or her disposal.

The usual piston is made of brass or other metal and may be made in two parts, that is to say a first part comprising the body of the piston and a second part in the nature of a flanged ring adapted to be screwed on the first part to hold the resilient closure member against an end face of said first part. Alternatively, the usual metal piston is provided with an undercut recess in an end face so that the old closure member can be extracted by being prized out and a new closure member inserted by flexing it so that its edges extend beneath the narrow flange provided by the undercut recess. However, the replacement of the resilient closure member can be rather difficult in both these case.For example, when a two piece piston has been in use for some time it can be difficult to dismantle, and of course a person previously fitting a replacement closure member may have over-tightened the second part on the first part, so that the job may require the use of tools and possibly of a vice. The replacement of the closure member in the one-piece metal piston described is difficult because the closure member really requires to be dished before its edges can be positioned beneath the narrow flange provided by the undercut recess.Because the dishing of the closure member is impossible in practice, the fitting is a slow process involving the thrusting or poking of the edge portions of the closure member by the blade of a small screwdriver of the like, and of course in this case it is quite easy to damage the sealing surface of the new closure member before it has been properly inserted in position.

The present invention aims to at least alleviate the difficulties referred to above.

According to one aspect of the invention, there is provided a piston for a ball float valve, the piston being made of moulded plastics with an undercut recess in an end face for the reception of a resilient valve closure member, a narrow flange which is provided by the undercut recess being a discontinuous flange so that there are at least two diametrically opposite points at which the flange is broken whereby a new closure member can very easily be inserted by folding it diametrically and feeding the opposite halves of the member into the recess through the mouth which is constituted by said diametrically opposite points where the flange is broken. The piston may be of generally cylindrical shape for sliding movement in a generally cylindrical valve chamber in a "Portsmouth" type ball float valve.

According to another aspect of the invention, there is provided, in combination, a synthetic plastics piston as described above and a resilient valve closure member in position in the undercut recess in its end face.

According to a still further aspect of the invention, there is provided a ball float valve provided with a synthetic plastics piston as described above.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Fig. 1 is a sectional elevation of a "Portsmouth" type ball float valve embodying the invention, Fig. 2 is a longitudinal section drawn to a larger scale than Fig. 1, through a synthetic plastics piston forming part of the float valve, and Fig. 3 is an end view in the direction of arrow 3 in Fig. 2.

Referring now to Fig. 1 of the drawings, the float valve there illustrated includes a generally tubular body 10 to one end of which is connected an inlet pipe 12. The body is bored through to form a valve chamber 14 and has an outlet passage 16, opening radially from the chamber. A valve seat member 20 is located in the valve body and has a central bore 22. A piston 24 is slidably mounted in the chamber 14 of the body 10 and carries, at the end nearest the valve seat, a resilient valve closure member 26 for closing the bore through the valve seat member.

A lever 30 carries a float 32 and forms one leg of a bell crank lever 34 which is pivotally connected to the body 10 on a pivot constituted by an easily removable split pin 36. The other arm or heel of the bell crank lever engages an aperture 38 in the piston so that the lowering or rising of the float by the water in the cistern causes the piston to respectively move away from or towards the valve seat member 20. In normal use, as water is drawn from the cistern in which the valve is fitted, the float falls and the valve opens to allow water from a supply main to flow through the valve chamber and into the cistern.

In Figs. 2 and 3 the form of the piston 24 is more clearly illustrated. It has been formed as a one-piece moulding in a synthetic plastics material, the aperture 38 having been formed in its side wall. An undercut recess 28 has been formed in an end face of the piston for the reception of the resilient valve closure member and, as best seen in Fig. 3, a narrow flange 40 which is provided by the undercut recess is a discontinuous flange, being broken at two diametrically opposite points 42 so that there is provided a mouth which is fully as wide as the diameter of the recess.

The arrangement is such that when, after long use, the resilient valve closure member has become worn so that the valve no longer closes effectively, the worn closure member can be removed and replaced by a new one relatively easily. To do this, the split pin 36 is removed so that the bell crank lever can be disengaged from the plunger and the latter can then be removed from the valve. The worn closure member can be extracted from the recess in the piston by the use of a small screwdriver blade or the like applied at one side or the other of the mouth referred to above. A new closure member can very easily be fitted by folding it diametrically and feeding the opposite halves of the member into the recess in the piston through the mouth constituted by the diametrically opposite points where the flange is broken.

Thus there is provided a piston for a ball float valve of the "Portsmouth" type the resilient valve closure member of which will be relatively easy to replace even after years of use. It will however be understood that modifications may be made to the piston described and illustrated in the drawings.

For example, the flange formed by the undercut recess could be provided with more than one pair of diametrically opposite gaps constituting the full width mouth referred to. It will be understood that the piston could be used in other kinds of piston type valves and not only in valves of the "Portsmouth" type.

Claims (5)

1. A piston for a ball float valve, the piston being made of moulded plastics with an undercut recess in an end face for the reception of a resilient valve closure member, a narrow flange which is provided by the undercut recess being a discontinuous flange so that there are at least two diametrically opposite points at which the flange is broken whereby a new closure member can very easily be inserted by folding it diametrically and feeding the opposite halves of the member into the recess through the mouth which is constituted by said diametrically opposite points where the flange is broken.

2. A piston according to claim 1, of generally cylindrical shape for sliding movement in a generally cylindrical valve chamber in a "Portsmouth" type ball float valve.

3. In combination, a synthetic plastics piston as claimed in either one of the preceding claims and a resilient valve closure member in position in the undercut recess in its end face.

4. A ball float valve provided with a synthetic plastics piston as claimed in any one of the preceding claims.

5. A ball float valve with a synthetic plastics piston constructed, arranged and adapted to be fitted with a resilient valve closure member in the manner hereinbefore described.