ZA200402452B

ZA200402452B - Cistern inlet valve

Info

Publication number: ZA200402452B
Application number: ZA2004/02452A
Authority: ZA
Inventors: Nicoll Sutherland John; VAN ZYL Christian; Thomas Tickle Karl
Original assignee: Zimco Group (Proprietary) Ltd
Priority date: 2002-09-13
Filing date: 2004-03-29
Publication date: 2005-06-29
Also published as: AU2003255900A1; WO2004025038A1

Description

A. ang “CISTERN INLET VALVE”

BACKGROUND TO THE INVENTION

THIS invention relates to a cistern inlet valve and in particular to a pressure-assisted toilet cistern inlet valve.

For the reason that they tend to be more compact than traditional pressure- opposed toilet cistern valves, pressure-assisted valves are increasing in popularity. Known pressure-assisted valves typically have a control chamber which is subdivided into first and second spaces by a laterally spanning diaphragm. :

In one known valve of this type, described in ZA 71/5572, after the cistern has been flushed inlet water enters the first space where its pressure displaces the diaphragm to an open position. This opens a main outlet leading to the cistern for replenishment of the water lost from the cistern during the flush. Water can also bleed from the first space to the second space through an eccentric bleed orifice in the diaphragm. A steel needle partially fills the bleed orifice. Water can leak out of the second space through an outlet orifice. When the cistern has filled with water, a float operated closure seals against the outlet orifice with the result that pressure in the upper space increases. The pressure-generated force acting on the diaphragm in the second space overcomes the pressure-generated force acting on the diaphragm in the first space with the result that the diaphragm moves to a closed position, terminating the flow of replenishing water into the cistern.

CONFIRMATION COPY

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In another known valve of this type, sold under the trade name

FLUIDMASTER, the operation is similar except that the inlet water bleeds from the first space to the second space through a centrally located bleed orifice in the diaphragm. This orifice is again partially filed by a steel needle. In this case, the needle also forms part of the float-operated closure which closes the outlet orifice from the second space when the cistern is full.

Other known pressure-assisted valves also incorporate a needle of steel or, in some cases, plastic. A problem with all known valves of this type is the increase in cost attributable to the provision of the needle.

SUMMARY OF THE INVENTION

According to the present invention there is provided a pressure-assisted cistern valve including: - areplenishing water inlet, - a cistern outlet, - adiaphragm, - a first pressure space on one side of the diaphragm which is exposed in use to replenishing water supplied to the inlet whereby the diaphragm is arranged to be biased by the pressure of the replenishing water to an open position in which it allows the replenishing water to flow to the cistern outlet,

Amended 23 June 2004

- a second pressure space on the opposite side of the diaphragm, - a hollow nipple fixed centrally to the diaphram and projecting downwardly from the diaphragm to a tip which is spaced from the diaphragm and located in the first pressure space, the nipple having a passage therein and a bleed orifice which is formed in the tip of the nipple, which is of smaller transverse dimension than the passage, and which has no pin or the like therein, the bleed orifice communicating with the passage and in combination with the passage defining a flow path to convey water through the diaphragm from the first pressure space to the second pressure space; and - a second outlet from the second pressure space, the second outlet including an outlet orifice aligned with the bleed orifice.

Other features of the invention are defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 - shows a cross-sectional view of a pressure-assisted toilet cistern inlet valve according to the invention;

Amended 23 June 2004

3A-

Figure 2 shows a top perspective view of the diaphragm used in the valve of Figure 1;

Figure 3 shows a bottom perspective view of the diaphragm;

Figure 4 shows a partial cross-sectional view of a second embodiment of pressure-assisted toilet cistern inlet valve according to the invention;

Figure 5 shows a perspective view of a cistern inlet valve according to the invention which is similar to that shown in Figure 1 but which incorporates some modifications; and

Figure 6 shows another perspective view of the cistern inlet valve seen in Figure 5. : Amended 23 June 2004

DESCRIPTION OF PREFERRED EMBODIMENTS

The pressure-assisted toilet cistern inlet valve 10 seen in Figure 1 includes an inlet conduit 12 composed of upper and lower sections 12.1 and 12.2 respectively. The lower section 12.2 has a threaded lower end 13which, in use, extends through an opening in the base of a toilet cistern and to which is connected a mains water supply pipe (not shown). The upper section 12.1 is a telescopic fit on the lower section. A collar 14 threaded onto the lower end of the upper section 12.2 can clip into any one of a number of vertically spaced grooves 18 in the lower section 12.2, thereby setting the overall length of the inlet conduit.

A filter 20 is fitted to an upper end of the lower section 12.2, inside the upper section 12.1, as illustrated. The upper end of the upper section 12.1 includes a central, conical formation 22 and an outer wall 24 onto which a collar 26 is threaded. The collar holds a cap 28 in place. An outer edge of a flexible rubber diaphragm 30, illustrated in Figures 2 and 3, is held captive between the cap and the upper edge of the wall 24.

Referring to Figures 2 and 3, the. diaphragm 30 is circular in shape and has a grooved peripheral edge which, as mentioned above, is held captive between the cap and the upper edge of the wall 24. A rigid, moulded, hollow nipple 32 is mounted in a central opening in the diaphragm and provides a hollow projection 34. A small bleed orifice 36, typically with a diameter of 0,7mm, is formed in the tip of the projection 34. When in position, the projection 34 extends downwardly into the conical formation 22 as illustrated in Figure 1.

The cap 28 is formed with an upwardly extending projection 38 formed with a small outlet orifice 40. Towards its inner end an arm 42 is attached pivotally to a bracket 44 on the cap by means of a transverse pivot pin 46.

Attached pivotally to the outer end of the arm 42 is the upper end of an elongate member 48 formed with a series of longitudinally spaced holes 50.

Towards its lower end, the member 48 is attached pivotally, through a selected one of the holes 50, to a bracket 52 extending laterally from an annular float 54, generally of inverted cup-shape, which can slide up and down the upper section 12.1 of the inlet conduit 12. The inner extremity of the arm 42 carries a seal 55 which can seat on the tip of the projection 38 of the cap, i.e. on the outlet orifice 40, to close it.

Projecting laterally from the outer wall 24 is an outlet spigot 56 onto the end of which is clipped a Tee-shaped extension 58. A delivery pipe 60 is connected the vertical Tee of the extension 58 and extends downwardly to a position alongside the lower section 12.2 of the inlet conduit 12, where it is held in place by a retainer 62. At the outer end of the extension 58 is a one-way vacuum-breaking valve 64, the function of which is described below.

A splash cap 66 clips over the cap 28 and is formed with a slot 68 in one side through which the arm 42 extends.

The upper end of the conduit section 12.1 and the cap 28 define between them a control chamber which is subdivided by the diaphragm 30 into upper and lower spaces 70 and 72 respectively.

Figure 1 illustrates the valve 10 after a flush has taken place from a cistern in which the valve is mounted. The float 54 is located at a low position on the section 12.1 of the inlet conduit 12. The arm 42 is pivoted to a position in which the seal 55 is raised above the orifice 40 in the cap 28, i.e. the orifice is open. Mains water flows up the inlet conduit 12 and enters the lower space 72. The pressure of the mains water is sufficient for the force which it generates in the space 72 to lift a central portion of the diaphragm 30, allowing water to flow over the edge of the conical formation 22, into the outlet spigot 56 and extension 58, and downwardly through the delivery pipe 60 to vent into the cistern at a position close the base of the cistern. In practice, a volume of water will always remain in the bottom of a cistern after a flush, and the arrangement of the valve 10, i.e, the length of the

-B- delivery pipe, will be such that the lower end of the delivery pipe is always below the water level so that the incoming water vents quietly beneath that water level.

A small proportion of the inlet water flowing up the inlet conduit 12 and/or in: the space 72 bleeds upwardly through the bleed orifice 36, into the upper space 70. Pressure does not build up in the space 70 because water in that space can leak into the cistern through the outlet orifice 40 in the cap 28.

The splash cap 66 prevents uncontrolled splashing of water which passes through the orifice. j

As the water level rises in the cistern, the float 54 is buoyed up. When the water level in the cistern has reached a predetermined level, determined by the degree of telescopic extension of the sections 12.1, 12.2 of the conduit 12, the buoyancy of the float causes the seal 55 to seat on the orifice 40, thereby closing the orifice and preventing further leakage of water from the upper space 70. As a result, pressure builds up in the space 70.

The area of the diaphragm 30 on which the pressure-generated force in the space 70 acts is greater than that on which the pressure-generated force in the space 72 acts. The resultant downward force on the diaphragm causes it to seat on the upper edge of the conical formation 22, thereby terminating communication between the inlet conduit 12 and the outlet spigot 56, i.e. water flow into the cistern ceases. It will be understood that the pressure of . the mains water assists in closing the valve.

When next the cistern is flushed and the water level therein drops, the float 54 slides down the inlet conduit 12, lifting the seal 55 off the orifice 40. The reduction in pressure in the space 70 allows the sequence of events described above to repeat itself.

An important feature of the valve 10 is the absence of any kind of pin in the bleed orifice 36. The absence of a pin allows the valve 10 to be manufactured more economically than is the case with known valves of the same general type in which a pin is provided in the bleed orifice.

Another feature of the valve 10 is the fact that the bleed orifice 36 is provided at the tip of the hollow projection 34. Particularly when the projection 36 extends downwardly as illustrated, it is extremely difficult for any fine particles in the flow of inlet water which may bypass the filter 20 to lodge in the orifice and block it. Added to this, the plastic material at the tip of the projection will typically only have a thickness of about 1mm, i.e. the orifice 36 itself only has a length of about 1mm, further reducing the chance of a blockage. Nevertheless, it will be understood that even if, despite these features, a blockage does take place, water will be unable to bleed into the space 70 and the valve will not close, i.e. water will run continuously into cistern but it will still be possible to flush the cistern.

The orifice 40 will in general be the same size as or bigger than the orifice 36, so the chances of blockage of that orifice are small.

The vacuum-breaking valve 64, which may be of a conventional type, allows air to be drawn into the valve in the event of sub-atmospheric conditions developing for any reason in the mains reticulation system, and thereby avoids the possibility of cistern water being sucked through the valve into that system. Ideally, the valve does not permit inlet water to flow out of the end of the extension 58 into the cistern.

Figure 4 shows a second embodiment of a pressure-assisted toilet cistern inlet valve 74 having a spigot section 76 which extends laterally from the wall 24 of the conduit 12. The spigot section 76 includes a Tee-shaped spigot 80 and a downwardly extending outlet 82. An extension 84 connects the vertical Tee of the spigot 80 with the outlet 82. A delivery pipe, corresponding to the delivery pipe 60 seen in Figure 1, is connected in use to the outlet. A vacuum-breaking valve, not shown in the drawing, can be located in a downwardly facing orientation towards the bottom of the outlet

It has been found that when a cistern with the inlet valve of Figure 1 is replenished, water may undesirably escape through the vacuum-breaking valve 64. In some instances this water may even spray out of the cistern.

The inlet valve shown in Figure 4 addresses this problem and ensures that any water which is sprayed from the vacuum-breaking valve is directed downwardly to the base of the cistern.

Figures 5 and 6 illustrate a cistern inlet valve which has many similarities to that of Figure 1 but which includes several modifications. Instead of the holed member 50 the embodiment seen in Figures 5 and 6 includes a downwardly extending member 90 which has spaced apart, ball-like projections 92 along its length. The projections 92 are spaced apart by sections 94 of narrow cross-section. Any selected one of these sections can be clipped to a bracket 96 carried by the float 54 as shown, thereby varying the effective length of the member: 90, the position of the float 54 and hence the flush volume.

In Figures 5 and 6 the conduit 12 is again of telescopic connection but in this case the collar 14 can be tightened ontd a slotted and threaded portion : 12.3 in order to clamp the relatively telescopic components 12.1 and 12.2 relative to one another at a selected position.

Claims

A pressure-assisted cistern valve including: - a replenishing water inlet, - acistern outlet, - adiaphragm, : - a first pressure space on one side of the diaphragm which is exposed in use to replenishing water supplied to the inlet whereby the diaphragm is arranged to be biased by the pressure of the replenishing water to an open position in which it allows the replenishing water to flow to the cistern outlet, - a second pressure space on the opposite side of the diaphragm,

- a hollow nipple fixed centrally to the diaphram and projecting downwardly from the diaphragm to a tip which is spaced from the diaphragm and located in the first pressure space, the nipple having a passage therein and a bleed orifice which is formed in the tip of the nipple, which is of smaller transverse dimension than the passage, and which has no pin or the like therein, the bleed orifice communicating with the passage and in combination with the passage defining a flow path to convey water through the

Amended 23 June 2004 diaphragm from the first pressure space to the second pressure space; and - a second outlet from the second pressure space, the second outlet including an outlet orifice aligned with the bleed orifice.

2. A cistern inlet valve according to claim 1 wherein the second pressure space is defined between the diaphragm and a rigid cap, and the outlet orifice is formed in the cap.

3. A cistern inlet valve according to claim 2 wherein the outlet orifice is formed in a tip of an upwardly projecting, hollow projection on the cap. " A cistern inlet valve according to any one of claims 1 to 3 wherein the replenishing water inlet comprises an inlet conduit of telescopic construction.

5. A cistern inlet valve according to claim 4 wherein flow through the outlet orifice is controlled by a valve closure responsive to the position of a float located slidably on the inlet conduit. Amended 23 June 2004

A cistern inlet valve according to claim 5 wherein the valve closure includes a seal movable between closed and open positions in which it seals against the outlet orifice and is spaced from the outlet orifice respectively, the seal being carried by a pivoted linkage connected to the float.

Amended 23 June 2004