AU694789B2 - A cistern inlet valve - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

*a a a *r 0 *i Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Caroma Industries Limited Market Street Brisbane Queensland 4000

AUSTRALIA

Timothy De Pieri Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia A Cistern Inlet Valve ASSOCIATED PROVISIONAL APPLICATION DETAILS [31] Application No(s) [33] Country [37] Application Date PM8031 AU 7 September 1994 The following statement is a full description of this invention, including the best method of performing it known to me/us:-

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A Cistern Inlet Valve The present invention relates to inlet valves for cisterns and, in particular, to the reduction of noise arising during the operation of such inlet valves.

A cistern inlet valve controls the flow of water into the cistern in order to replenish the water stored therein immediately following flushing of the toilet. During the very short period whilst the flushing of the lavatory pan takes place, the noise created by water flowing through the inlet valve is not of great consequence because it is masked by the noise of the flush. However, after the cessation of the flush the noise of water flowing through the inlet valve is normally able to be heard. In domestic circumstances this is a source of annoyance, however, in commercial premises such as hotels it can be a substantial source of guest dissatisfaction.

Normally, in order to reduce noise, the outlet of the cistern inlet valve is located low down in the cistern to reduce noise as much as possible, :"In almost all jurisdictions, it is a requirement for cistern inlet valves that the 15 valve outlet be provided with a siphon breaking aperture which interconnects the atmosphere with the outlet. In the rare, but technically possible, event that the cistern 'inlet valve is open and a low pressure or substantial vacuum should happen to present S"in the mains to which the inlet of the inlet valve is connected, then the role of the aperture is to allow air into the outlet of the valve. This thereby prevents the circumstances arising where water siphons from the cistern in the reverse direction 0 through the open inlet valve and into the mains.

Australian Patent No. 616,359 (to which US Patent No. 4,938,245 correspcilds) discloses a cistern inlet valve in which a column of "stagnant" water is *used to occlude, during operation of the inlet valve, the siphon breaking opening between atmosphere and the outlet of the val, e.

.al As indicated in the introductory portion to that specification, a cistern inlet "valve of the type which has an outlet tube which carries water to near the bottom of the cistern and which also has a anti-siphon opening, but which created minimal noise during refilling of the cistern, would be of considerable value.

It is known from TJS Patent No. 4,100,928 to provide an anti-siphon device in the form of a generally conical rubber member which has the general advantage of "collapsing" in the event of reverse flow and thereby tending to seal the outlet from the inlet. However, in this specification, at least one air vent opening 102 is formed in the anti-siphon rubber member 98 to ensure that there is air communication between the atmosphere and the valve seat. Such an arrangement provides two disadvantages.

Firstly, during operation of the valve water and/or noise may be able to pass through the vent 102 and thence out to atmosphere. Secondly, it is possible for air to be entrained within the outlet water by passing inwardly through the air vent 102. In IN:ALIB001287,Cg 44 t 4'tD 44 4 Lt *r 4 1 -2either event, additional noise is created. In US Patent No. 4,100,928 this additional noise is minimised by making the air path from the vent 102 to atmosphere as circuitous as possible.

It is the object of the present invention to provide a method and apparatus whereby the noise generated by the operation of a cistern inlet valve can be reduced, notwithstanding that the inlet valve is provided with a siphon-breaking aperture interconnecting the outlet of the valve to atmosphere.

In accordance with a first aspect of the present invention there is disclosed a method of reducing noise generated by operation of a cistern inlet valve, said method comprising the steps of: providing a flow restricting variable orifice'down stream of said inlet valve, said orifice being of variable size and adapted to expand in size with increasing flow through said inlet valve, and utilizing the expansion of said variable orifice to substantially close a siphon breaking aperture interconnecting an outlet of said cistern inlet valve to atmosphere to thereby substantially prevent entrainment of atmospheric air into liquid passing through said value outlet.

The method preferably includes the additional step of: directing the liquid leaving said valve outlet through an outlet passage or 20 passages disposed immediately downstream of said valve outlet, the cross-sectional area of each of the passage(s) being restricted relhtive to the cross-sectional area of the said valve outlet.

The method preferably also includes the further step of: directing the liquid leaving the outlet passage(s) through an inlet valve cistern 25 interior outlet, said cistern interior outlet being of restricted cross-sectional area relative to the cross-sectional area of the passage(s) and disposed adjacent the point of entry of the inlet valve into a cistern interior to thereby substantially fill said cistern interior outlet with liquid during operation of said inlet valve.

In accordance with a second aspect of the present invention there is disclosed a 30 cistern inlet valve having an inlet, an outlet, a valve seat closable by a valve body, a flow restricting variable orifice down stream of said valve seat and located in the path of liquid flowing through said cistern inlet valve and into said valve outlet, and a siphon breaking aperture open to atmosphere and in fluid communication with said outlet, wherein said variable orifice is adjacent said aperture and occludes same by expansion of said variable orifice in response to increased flow through said cistern inlet valve to thereby substantially prevent entrainment of atmospheric air into liquid leaving said valve outlet.

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4 4 2a Preferably, the cross-sectional area of a passage or passages immediately downstream of said outlet is restricted relative to the cross-sectional area of said valve outlet.

Preferably also, the cross-sectional area of a cistern interior outlet downstream of said passage(s) is restricted relative to the cross-sectional area of the passage(s), the cistern interior outlet disposed adjacent the point of entry into a cistern interior of the cistern iiilet valve to thereby substantially fill the cistern interior outlet with liquid during operation of the cistern inlet valve.

Desirably, the cistern inlet valve also includes a cylindrical outlet conduit o1 surrounding a cylindrical inlet conduit, wherein the variable orifice is defined between the outer surface of the inlet conduit and an inner surface of an elastomeric sleeve surrounding the inlet conduit.

Desirably also, the sleeve inner surface sealingly bears against the inlet conduit outer surface in the absence of flow and/or pressure downstream of said valve seat.

9 0 0s4 9 9909 *I 6 9. t 4 9. r .4I *c '.4 rMIT tdrtfMAC.ii i :i C1 iii____ibl__ij(i/_CLYY_~ -3- An embodiment of the present invention will now be described with reference to the drawings in which: Fig. 1 is a side elevation of the inlet valve of the preferred embodiment, Fig. 2 is an exploded perspective view illustrating the assembly of the various items which make up the valve itself, and Fig, 3 is a longitudinal cross-sectional view taken through the valve.

As seen in Fig, 1, the inlet valve 1 of the preferred embodiment sits at the top of a stem 2 on which a float 3 rises or falls in accordance with the level of water within the cistern. The float 3 is connected to the inlet valve 1 by means of a float arm 4.

The rack and pinion mechanism 5 which interconnects the float arm 4 and the inlet valve 1 is the subject of applicant's co-pending Australian Patent Application No. PM8030 (Attorney Reference: 277514). Similarly, the float 3 is the subject of applicant's co-pending Australian Patent Application No. PM8032 (Attorney Reference: 277542). Both applications are filed simultaneously herewith.

15 The stem 2 is formed from two concentric cylindrical members, the inner one of which is the inlet 7 which is surrounded by the outlet 8. Adjacent the base of the outlet are one or more openings 9 which restrict the outlet flow as will be explained "".hereafter. The entire arrangement is able to be mounted in known fashion in an opening in the base of the cistern (not illustrated) and sealingly clamped in position by 20 means of a nut The interior detail of the valve itself is illustrated in Figs. 2 and 3. The inlet valve 1 is of the type described in Australian Patent Application No. 72899/94 (previously Application No. PM1316) (Attorney Reference 281002) the contents of both of which are incorporated into this specification by means of cross reference.

As best seen in Fig. 3, the inlet 7 opens into a valve chamber 12 which :includes an egg-Jlike valve body 13 which is positioned at the lower end of a valve stem 14. The valve stem 14 is able to be raised or lowered by means of the rack and pinion mechanism 5 and float arm 4 in order to respectively close and open the valve 1. The valve chamber 12 is formed from two pieces, the upper one of which constitutes the valve seat 15. An O-ring 16 is clamped between the valve seat 15 and the remainder of the valve chamber 12.

Three generally U-shaped passages 18 of restricted cross-sectional size lead from the valve seat 15 into an annular chamber 19 which in turn opens into the outlet 8.

The U-shaped passages 18 are formed by grooves positioned in the underside of a cap 21 (Fig. The cap 21 is able to be secured to a bell 22 formed at the upper end of the stem 2 by means of bayonet fittings 23, 24. In this way the cap 21 can be secured to the bell 22 so as to clamp the valve seat 15 into position.

[N:\LIBOO]00287:Cg I T 11, 1. 1 I 1, "1 i 0 1 1 0_40404 O "O ft X W n 00 "i .p 1~ il~l -4- A number of openings 25 extend through the bell 22 and thus permit air to be communicated from the atmosphere, via the annular space between the skirt of the cap 21 and the bell 22, and thence into the annular chamber 19. Positioned between the cap 21 and bell 22 is a frusto-conical rubber sleeve 26. The upper end of the sleeve 26 is formed with a rim 27 which functions as an O-ring and provides a seal between the bell 22 and cap 21. The sleeve 26 is provided with a central aperture 28 (Fig. 2) which, in the rest position illustrated in Fig. 3, presses against the exterior of the valve chamber 12.

The operation of the inlet valve 1 is as follows. When the inlet valve 1 is closed, the valve stem 14 is in the raised position, thereby ensuring that the valve body 13 abuts the valve seat 15 to prevent the flow of water through the valve. In this connection the mains pressure applied to the inlet 7 is of assistance.

When the valve stem 14 is lowered by the float arm 3 pivoting in the anti- I clockwise direction as seen in Fig. 3, then water is able to flow from the inlet 7, 15 through the valve chamber 12, past the valve seat 15 and into the U-shaped passages 18. Since the passages 18 follow a smooth curve, this flow exhibits streamlined behaviour which therefore minimises turbulence and its associated noise.

In addition, the rubber sleeve 26 which initially blocks the flow of water from the U-shaped passages 18 into the annular chamber 19 is deformed outwardly by the 20 water pressure now applied to the inner surface of the sleeve 26 via the open valve seat 15. The consequence of this pressure and the resulting water flow is that the rubber sleeve 16 expands outwardly so as to increase the effective diameter of its central aperture 28.

This movement of the rubber sleeve 26 provides two simultaneous effects.

Firstly, the gap between the valve chamber 12 and the central aperture 28 of the rubber sleeve 26, effectively constitutes a variable aperture orifice which increases with S* increasing flow and/or pressure. This has the very desirable advantage of providing a pressure drop close to the valve seat In addition, the expansion of the rubber sleeve 26 radially outwardly under the influence of the water passing through the inlet valve 1, results in the central portion 29 of the rubber sleeve 26 effectively sealing the openings 25. As a consequence, no air can pass from atmosphere through the openings 25 and thereby be entrained with the water passing from the U-shaped passages 18 into the annular chamber 19 and thence into the outlet 8. This constitutes a very substantial noise reduction measure.

Finally, the restricted openings 9 at the base of the outlet 8 mean that the outlet 8 is quickly completely filled with water during operation of the valve. As a consequence, a substantial amount of splashing and bubbling noise is eliminated.

Furthermore, the openings 9 are preferably of a restricted size so as to constitute a ;i [NA\LIBOOJOO287:cg I_ i i rr I Ur-.LI-ILLL1L""~~ further pressure drop generating device. As a consequence the mains pressure is dropped in stages between the inlet and outlet thereby reducing the tendency for cavitation to occur in any one place. It is the water pressure dropping below the water vapour pressure which gives rise to cavitation, and hence cavitation noise.

It will be apparent to those skilled in the art that the above described arrangement provides a number of advai.tages. Firstly, the smallest passage in the inlet valve which is likely to be clogged by any grit or debris carried in the inlet water, is located at the valve seat 15. As a consequence, should any material be lodged at this position, it is likely to be dislodged at the next operation of the valve. Furthermore, any such material is able to be easily carried through the passages I8, past the central aperture 28 of the rubber sleeve 26 and into the annular chamber 19. From there any such debris is able to pass harmlessly into the interior of the cistern.

In addition, should there happen to be a partial vacuum applied to the inlet 7 whilst the inlet valve 1 is open, then the rubber sleeve 26 will be sucked inwardly I S. 15 thereby clamping the central aperture 28 against the exterior of the valve chamber 12.

Furthermore, the central portion 29 of the rubber sleeve 26 will move inwardly thereby .freeing the openings 25 and allowing atmospheric air into the outlet 8. As a consequence, any water in the outlet 8 will drop to the level of water within the cistern.

In this way the prevention of any reverse siphoning is ensured.

20 The foregoing describes only one embodiment of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. For example, all the openings between the annular chamber 19 and the outlet 8 can be inclined in the same direction so as to impart a swirling motion to the water which enters the outlet 8.

".'"impart a swirling motion to the water which enters the outlet 8.

4 4 4 44 44 INLIBOOIOO287xcg

Claims (12)

1. A method of reducing noise g-nerated by operation of a cistern inlet valve, said method comprising the steps of: providing a flow restricting variable orifice down stream of said inlet valve, said orifice being of variable size and adapted to expand in size with increasing flow through said inlet valve, and utilizing the expansion of said variable orifice to substantially close a siphon breaking aperture interconnecting an outlet of said cistern inlet valve to atmosphere to thereby substantially prevent entrainment of atmospheric air into liquid leaving said valve outlet.

2. A method as claimed in claim 1 including the additional step of: directing the liquid leaving said valve outlet through an outlet passage or passages disposed immediately downstream of said valve outlet, the cross-sectional area of each of the passage(s) being restricted relative to the cross-sectional area of the said 15 valve outlet.

3. A method as claimed in claim 2 including the further step of: 44(t c directing the liquid leaving the outlet passage(s) through an inlet valve cistern interior outlet, said cistern interior outlet being of restricted cross-sectionai area relative to the cross-sectional area of the passage(s) and disposed adjacent the point of entry of t 20 the inlet valve into a cistern interior to thereby substantially fill said cistern interior outlet with liquid during operation of said inlet valve.

4. A method as claimed in any one of claims 1 to 3, wherein said flow restricting variable orifice is substantially closed when said inlet valve is closed. f 4 C SC

5. A method of reducing noise generated by operation of a cistern inlet 64 410 0, 25 valve, said method being substantially as herein described with reference to the :6 accompanying drawings.

S° 1 C6. A cistern inlet valve having an inlet, an outlet, a valve seat closable by a valve body, a flow restricting variable orifice down stream of said valve seat and located in the path of liquid flowing through said cistern inlet valve and into said valve S 30 outlet, and a siphon breaking aperture open to atmosphere and in fluid communication with said outlet, wherein said variable orifice is adjacent said aperture and occludes same by expansion of said variable orifice in response to increased flow through said cistern inlet valve to thereby substantially prevent entrainment of atmospheric air into liquid leaving said valve outlet.

7. A cistern inlet valve as claimed in claim 6, wherein the cross-sectional area of a passage or passages inmmediately downstream of said outlet is restricted relative to the cross-sectional area of said valve outlet. ILI n -7-

8. A cistern inlet valve as claimed in claim 7, wherein the cross-sectional area of a cistern interior outlet downstream of said passage(s) is restricted relative to the cross-sectional area of the passage(s), the cistern interior outlet disposed adjacent the point of entry into a cistern interior of the cistern inlet valve to thereby substantially fill the cistern interior outlet with liquid during operation of the cistern inlet valve.

9. A cistern inlet valve as claimed in any one of claims 8, including a cyhndrical outlet conduit surrounding a cylindrical inlet conduit, wherein the variable orifice is defined between the outer surface of the inlet conduit and an inner surface of an elastomeric sleeve surrounding the inlet conduit.

10. A cistern inlet valve as claimed in claim 9, wherein said sleeve inner surface sealingly bears against the inlet conduit outer surface in the absence of flow and/or pressure downstream of said valve seat.

11. A cistern inlet valve as claimed in claim 10, wherein said siphon breaking aperture is located adjacent said sleeve and is closed by outward expansion of 15 said sleeve.

12. A cistern inlet valve substantially as herein described with reference to the accompanying drawings. tt t t 20 DATED this Fifth Day of June 1998 Caroma Industries Limited Patent Attorneys for the Applicant SPRUSON FERGUSON €1 c .1 [N:\LIBd100451:Iam <ni~j i I A Cistern Inlet Valve Abstract A cistern inlet valve is disclosed having a variable flow restricting orifice (28, 12) down stream of the valve. The movement of an elastomeric sleeve 26 forming the orifice closes a siphon breaking aperture (25) to prevent entrainment of atmospheric air in the flow. The cross-sectional area immediately down stream of the valve is also restricted as is the cross-sectional area of the outlet 9). Figure 2 t Ir I Il I 9$ I I (I C Ir J( N:ALIBOO]OO287;cg