AU692900B2 - A float for a cistern - Google Patents

Description

I

S F Ref: 303182

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

o s r o r o Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Caroma Industries Limited 10 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 Float for a Cistern ASSOCIATED PROVISIONAL APPLICATION DETAILS [311 Application No(s) E333 Country PM8032 AU C32] Application Date 7 September 1994 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815 A Float for a Cistern The present invention relates to floats for cisterns and, in particular, to a combined float and weight for cistern inlet valves.

Cistern inlet valves are used to replenish cisterns following the flushing of toilets. The cistern inlet valve is opened by the drop in the water level within the cistern which occurs immediately after flushing commences. The cistern inlet valve is closed when the water level has been refilled to a predetermined height.

In order to initiate the valve opening, the float must have sufficient weight to operate the actuating mechanism of the valve. Similarly, in order to close the actuating mechanism of the valve a sufficient upward buoyant force must be applied by the float.

It is known from US Patent No. 4,703,653 to utilise a combined weight and float in which the weight is provided by a layer of water maintained in the bottom of a bucket and flotation is provided by a body of air trapped within a downwardly facing substantially airtight concave float body.

It is particularly desirable in relation to cisterns to quickly complete the cistern filling procedure. This is because there is generally some noise associated with the flow of water into the cistern and this noise is often objectionable. Therefore, if the cistern refilling procedure can be completed in a minimum time, this minimises the length of time during which there is any noise. Furthermore, some cistern inlet valves have an extended close-off which is especially noisy in regions of high inlet water pressure. As a consequence, the refilling procedure can continue for a very long period of time.

Some types of inlet valve, for example that described in Australian Patent Application No. 72899/94 (previously Application No. PM1316) (Attorney Reference 281002) which is unpublished and unsold as of the priority date of this application, display a considerable amount of hysteresis in the valve characteristic. That is to say, in particular, the force required to close the valve is greater than the minimum force to Smaintain the valve closed. The present invention, although not limited to such valves, finds particular application in conjunction with such valves.

It is the object of the present invention to provide a combined float and weight for cistern inlet valves, and a method of positively closing an inlet valve in which during closing a dual buoyant upward force is generated by a pair of floats and in which after closing only one of the floats is utilised.

In accordance with the first aspect of the present invention there is disclosed a combined float and weight for cistern inlet valves, said float comprising a pair of substantially airtight downwardly facing concave float bodies spaced apart from an upwardly facing water retaining bucket, the downwardly facing bodies each terminating in a lower rim, the rim of a first one of said float bodies being lower than the rim of the I second one of said float bodies.

INA\LI300100288DM In accordance with the second aspect of the present invention there is disclosed A method of positively closing an inlet valve, said method comprising the steps of using a pair of connected floats, one of said floats comprising a volume of air trapped by water rising above a final float level corresponding to a maximum cistern flush volume, wherein a pair of buoyant forces are applied whilst said pair of floats are partially submerged to below said final level during filling, and only a single buoyant force is applied after filling when said float reaches said final level.

Two embodiments of the present invention will now be described with reference to the drawings in which: Fig. 1 is a side elevation of a combined inlet valve and float arrangement of the first embodiment, Fig. 2 is a vertical cross-sectional view taken through the inlet valve of Fig. 1, Fig. 3 is an exploded perspective view of the float illustrated in Fig. 1, Figs. 4 to 7 are schematic cross-sectional views through the float of Figs. 1 and 3 illustrating the operation of the device, Fig. 8 is a view similar to Fig. 3 but of the float arrangement of the second embodiment, and Figs. 9 to 12 are views similar to Figs. 4 to 7 but of the float arrangement of Fig. 8.

As seen in Fig. 1, the float 1 of the first embodiment is arranged for sliding motion along the stem 2 of an inlet valve 3. The float 1 is connected to the inlet valve 3 by means of a float arm 4 and a turnbuckle 5 which is pivotally connected at one end to the float 1 and at the other end to the float arm 4.

The float arm 4 is connected to the inlet valve 3 via a rack and pinion 25 mechanism 7 more fully described in applicant's co-pending Application No. PM8030 (Attorney Reference: 277514). The entire arrangement is able to be mounted within an opening formed in the base of a cistern (not illustrated) and clamped into position by means of a substantially conventional nut 8.

As illustrated in Fig. 2, the inJt valve 3 has an inlet 10 leading into a valve 30 chamber 11. A valve body 12 is located at the lower end of a valve stein 13 and is able to close a valve seat 14. From the valve seat 14 a number of U-shaped passages lead to the outlet 16.

As described in the above mentioned Australian Patent Application No. 72899/94 (previously Application No. PM1316) (Attorney Reference 281002) (the contents of both of which are hereby incorporated into the disclosure of this specification by cross-reference) the inlet valve 3 is closed when the valve body 12 is in its raised position. In this position the valve body 13 occludes the valve seat 14 and the pressure of the inlet water holds the valve body abutting against the valve seat 14. If o 00 0 *0 0 0 oo o o o BA4/ iiL 9 iN;\LIBOO100288:DMB I _1_1~ -3the valve body 12 is moved downwardly towards the inlet 10, then once an equilibrium position is passed, the pressure between the valve body 12 and the lower part of the valve chamber 11 is less than the pressure between the valve body 12 and the-valve seat 14 and, as a consequence, the valve 3 remains open.

Conversely, once the valve body 12 is raised upwardly beyond the equilibrium position, then the pressure between the valve body 12 and the valve seat 14 is less than the pressure on the lower portion of the valve body 12 thereby closing the valve. It is desirable in order to avoid water hammer that the valve also not close too quickly.

As seen in Figs. 1 and 3, the float 1 itself is formed from two components, a lower bucket 18 and a pair of downwardly facing inner and outer floats 19, 20. Both the bucket 18 and the floats 19, 20 are provided with a pair of mutually engagable sleeves 21, 22. The lower sleeve 22 is formed with the bucket 18 and includes a pair of releasable arms 23. The upper sleeve 21 has a pair of corresponding grooves 24 and thus the two parts 18 and 19, 20 are able to be snap engaged so as to provide a through sleeve which provides a slide for the float 1 on the stem 2.

As indicated in both Figs. 1 and 3, the bucket 18 has a hole 26 and a rim 27.

,..The inner:float 19 has a rim 28 which is lower than the rim 29 of the outer float When assembled the rim 27 and rim 29 are spaced apart by a gap which enables water to enter into the bucket 18 over the rim 27. Neither the inner float 19 nor the outer :20 float 20 has any air escape hole and thus these floats are substantially airtight.

Figs. 4 to 7 illustrate the sequence of events following the commencement of the flushing action and in which Fig. 7 represents both the final float position and the initial float position.

Turning now to Fig. 8, a float 101 is basically as before with all designations increased by 100 in magnitude save that the inner float 19 is re-located as a lower float 119 positioned on the underside of the bucket 118. The lower rim of float 119 is 128.

In addition the hole 26 is no longer required.

Thus the two floats take the form of the upper float 120 and the lower float 119. Otherwise the arrangement is essentially unchanged.

The operation of the float 101 will now be described with reference to Figs. 9 to 12.

In the initial and final positions illustrated in Fig. 12, the float 101 floats at a final float level 131 in which both the rims 127 and 128 are submerged but the rim 129 is above the water level. As a consequence, there is no air trapped in the upper float 120. However, there is air tiapped, and partially compressed, within the lower float 119.

When flushing is initiated, the level of water within the cistern rapidly falls so that the float 1 is increasingly submerged to a lesser and lesser degree. When the water (N:\L1800B100288cg -4level falls below the rim 127, the bucket 118 remains full and thus of constant mass. In addition, increasingly buoyantly unsupported weight of water contained within the bucket 118 is sufficient to move the float arm 104 anti-clockwise as seen in Figs. 9 to 12 to thereby initiate the opening of the inlet valve. As the water level falls the effective weight of the bucket 118 will increase up to a maximum weight. The minimum weight required to open and maintain the inlet valve 103 open will always be less than this maximum weight.

As water flows into the cistern the level of water within the cistern rises and the position is as illustrated in Fig. 10. Here the level of water has risen over the rim 128 to trap air within the lower float 19, As a result, the float 101 rises but, as before, this rise will be less fast than the rise of water within the cistern.

The next stage is illustrated in Fig. 11 where the water level has risen sufficiently to rise above the rim 129 of the upper float 120. As a consequence, air is trapped in the upper float 120. As a consequence of this air entrapment, the total buoyant force of the float 101 is increased and a large buoyant force is therefore available to move the valve stem 113 (via the action of the float arm 104) past the equilibrium point of the inlet valve 103. As a consequence, the inlet valve 103 begins to close, however, the float 101 which is still below its final position, brakes or slows S the movement of the valve stem 113. This reduces water hammer.

The momentum and inertia of the rising valve body 112 carry the float 101 past its final position and, as a consequence, the rim 129 of the upper float 120 rises above the actual water level within the cistern. As a result, the small volume of water which is positioned within the upper float 20 and above the rim 129 is able to fall downwardly into the cistern. This happens because the weight of the water retained 25 above the rim 129 exceeds the surface tension of the water trapped in the lower most regions of the float 120. A small notch 150 (Fig. 8) in the rim 129 assists in !his connection.

As a consequence, the total weight of the float 101 is reduced and the float 101 therefore rises so as to locate the rim 29 clear of the final water level 31.

The foregoing describes only two embodiments 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.

IN:\LIB20000288:cg

Claims (7)

1. A combined float and weight for cistern inlet valves, said float comprising a pair of substantially airtight downwardly facing concave float bodies spaced apart from an upwardly facing water retaining bucket, the downwardly facing bodies each terminating in a lower rim, the rim of a first one of said float bodies being lower than the rim of the second one of said float bodies.

2. A combined float and weight as claimed in claim 1 wherein both floats are located above said bucket with the rim of a first one of said floats being located below the rim of said bucket, the rim of the second one of said floats being located above the rim of said bucket, and said bucket including a bleed hole located therein below the rim of said first float,

3. A combined float and weight as claimed in claim 2 wherein said first float is located within said bucket.

4. A combined float and weight as claimed in claim 1 wherein a first one of said floats is located below said bucket and the second one of said floats is located above said bucket with the rim of said second float being located above the rim of said bucket. A combined float and weight as claimed in claim 4 wherein the base of said bucket comprises the top of said first float.

6. A combined float and weight substantially as herein described with reference to Figs. 1 to 7 or Figs. 8 to 12 of the accompanying drawings. te 7. A method of positively closing an inlet valve, said method comprising the steps of using a pair of connected floats, one of said floats comprising a volume of air trapped by water rising above a final float level corresponding to a maximum cistern

9.9. 25 flush volume, wherein a pair of buoyant forces are applied whilst said pair of floats are partially submerged to below said final level during filling, and only a single buoyant force is applied after filling when said float reaches said final level. i 8. A method as claimed in claim 7 wherein each of said floats are formed by a corresponding volume of air trapped by water rising in the cistern to which said 30 inlet valve is connected, and the volume of air trapped in said one float is trapped after the volume of air trapped in the other said float. 9. A method as claimed in claim 7 or 8 wherein a water filled bucket is i used to provide a downwardly directed force applied to each of said buoyant forces. A method as claimed in claim 9 wherein said final float level is determined by a balance between said single buoyant force and said downwardly directed force. N:;\LIBOOIOO288:DMB 1 6 I -6-

11. A method of positively closing an inlet valve, said method being substantially as herein described with reference to Figs. 1 to 7 or 8 to 12 of thle accompanying drawings. DATED this Ninth Day of August 1995 Caroma Industries Limited Patent Attorneys for the Applicant SPRUSON FERGUSON (NALIBOOIOO288:Cg I p A Float for a Cistern Abstract A two float and weight arrangement for positively closing a cistern inlet valve 103) is disclosed. Two floats (19, 20; 119, 120) and a bucket (18, 118) are provided. Air trapped within the floats by rising water provides an initial and second buoyant force. The second buoyant force raises the arrangement beyond its final level to release the trapping effect on the second float (20, 120). Figures 3 and 8 *S 9 59 «m 9 999 I ID (N:\UBOO10O288:cg ~1 Ire p II I I