GB2441532A

GB2441532A - Delayed action float valve for W.C. cistern

Info

Publication number: GB2441532A
Application number: GB0617469A
Authority: GB
Inventors: Dennis Raymond Henson
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-09-06
Filing date: 2006-09-06
Publication date: 2008-03-12
Anticipated expiration: 2026-09-06
Also published as: GB0617469D0; GB2441532B

Abstract

A cistern having a delayed action float controlled liquid inlet valve (10) which includes a float chamber (30) in the cistern within which the valve float (18) is located, which chamber fills with liquid in use to cause the valve float to rise and close the valve, and in which a siphon tube is provided for emptying the chamber when the cistern is emptied and one branch of the siphon tube extends externally of the float chamber, to a point which is enclosed within a shroud (58) and is below the base of the float chamber.

Description

DESCRIPTION

Title:-Water Saving Device.

Field of invention.

This invention concerns water cisterns, especially cisterns that are replenished using float operated valves in which the float rides on the surface of the water in the cistern and regulates the incoming water supply. The invention also concerns an improved design of siphon.

Background to invention.

As soon as the water level in such a cistern begins to drop when the associated WC is flushed, the valve opens to replenish the water within the cistern. This occurs while it is emptying into the toilet pan. As a result water intended to replenish the cistern also flows into the toilet pan for the duration of the flushing cycle. This increases the water used for flushing unnecessarily, and the water is effectively wasted.

A device is disclosed in GB Patent Application 9709227.4 called a delayed action float valve. This has been marketed to try to overcome the aforementioned wastage. However because the cistern water level and float positions change the amount of delay the device is time consuming to fit and adjust, and the delay can also vary according to the incoming water pressure and flow rate. The device comprises a separate upwardly open float chamber into which water flows as the cistern reaches a fzll condition, and the float is lifted to close the valve by the water in the chamber rather than the water in the cistern itself. The chamber has a very small hole in its base through which some water enters the chamber as the cistern fills, but through which all the water has to drain from the chamber into the cistern, after the WC is flushed and the main body of water flows into the pan.

Since the water in the float chamber takes a relatively long time to drain out through the small hole, the dropping of the float and the opening of the valve is delayed.

Because it has to be small, the hole can get blocked by debris or scale. However, if the size of the hole is increased to overcome this problem, water drains too quickly from the float chamber and the valve opens prematurely.

The delayed action float valve device also ceases to function reliably if the water pressure supplying the cistern drops. The cistern will then fill very slowly and the rate of flow upwardly through the aforementioned hole, into the float chamber, can equate to the rate at which the water rises in the cistern. This can cause the valve to shut prematurely, and results in the cistern not being completely filled and flushing may not then fully clean the pan.

Summary of invention

According to the broadest aspect of the present invention in a float chamber as aforesaid for a delayed action float valve the drainage hole is replaced by a siphon tube, one branch of which extends externally of and below the base of the float chamber.

According therefore to the present invention in a cistern having a delayed action float controlled liquid inlet valve which includes a float chamber in the cistern within which the valve is located, which chamber fills with liquid in use to cause the valve float to rise and close the valve, a siphon tube is provided for emptying the chamber when the cistern is emptied and one branch of the siphon tube extends externally of the float chamber, to a point which in use is below the base of the float chamber.

Preferably the lower end of the said one siphon branch communicates with an inverted cup-shaped shroud and the siphon tube protrudes into the shroud.

Preferably the end face of the lower external end of the one siphon; branch extends at an acute angle to the axis of the tube, so that the lower external end thereof is not square to its axis, to assist in discharging air bubbles which reach the external end of the branch.

Preferably the said one branch of the siphon tube extends through the base of the cistern, and the protruding part has at least one narrow slit in the wall thereof which extends over some or all of the length of the protruding part.

The slit is preferably selected so that the surface tension of liquid in the protruding part of the siphon tube prevents air in the liquid which has formed bubbles from leaving via the slit; thereby forcing the air bubbles to pass to the bottom of the protruding part before they can leave, whereas when the reservoir is empty and there is no liquid in the protruding part, air trapped below the float chamber as the cistern refills, is free to pass through the slit into the siphon tube, so that air trapped below the chamber is forced into the siphon tube ahead of a rising liquid level.

Thus in one embodiment of the invention the siphon is an inverted U-tube one branch of which protrudes through the base of the float chamber and has at least one slit in the wall thereof where it extends bellow the base of the float chamber, the end face of the protruding part is not square to the axis of the protruding part but lies at an acute angle thereto, and the protruding part is surrounded by a shroud which creates with the underside of the float chamber an inverted cup-shaped enclosure in which any escaping air bubbles will accumulate and from which the air will be displaced via the silt into the siphon tube ahead of liquid rising up in the enclosure as the cistern refills.

When the liquid level in the float chamber has risen so that the float has been raised sufficiently to close the valve, the siphon tube generally will be uIill of liquid except for a small bubble of air which tends to be trapped at the crown of the U-bend. It is this air which is displaced as one or more bubbles in the liquid, and has to pass right to the very bottom of the longer branch of the U-tube as the siphon is next initiated to empty the float chamber. It is the reliable displacement and discharge of this air bubble which purges the siphon tube of air and reliably starts the siphon to empty the float chamber.

Typically the float chamber serves as a catchpot which is emptied by the siphon each time the cistern is emptied thereby generating a constant delay before the inlet valve is opened.

According to a preferred aspect of the invention the siphon flow rate is adjustable to allow the delay in the vale opening to be adjusted.

The siphon flow rate is preferably adjustable after installation of the valve and float chamber in the cistern Typically the cistern is emptied through a second siphon, and once emptied, the liquid cannot exit via the second siphon until flow through the latter is initiated.

Some water cisterns are of dual flush type, with a full or half flush mode depending on selection, and the invention is also applicable to these cisterns.

The rate that water cisterns empty varies according to the discharge mechanism, faster cisterns can purge small siphons without the need of one branch of the siphon protruding into the shroud.

Tests have shown that siphons with a bore small enough to ensure the slow rate of emptying do not easily self purge. This is especially so if the cistern has full and half flush modes of operation, since in the half flush mode the water level in the cistern only falls a small distance, which may not be sufficient to establish the siphon to empty the float chamber.

According therefore to a preferred aspect of the present invention in a cistern as aforesaid the siphon tube in the float chamber comprises an inner upright tube which extends through and above and below the base of the float chamber and upwardly from the base to a point higher than the upper edge of the float chamber, and the other branch of the siphon is created by fitting a closed sleeve over the upstanding end of the upright inner tube so that a passage exists from the top to bottom of the sleeve between the inside thereof and the outside of the inner tube, and a first gap exists between the upper open end of the inner upright tube and the upper closed end of the sleeve, and a second gap exists between the lowermost edge of the sleeve and the base of the float chamber so that when a siphon is initiated liquid can pass through the second gap into and up the sleeve between it and the tube and thereafter down the upright tube, to discharge through the lower end thereof In such a siphon the size of the second gap which determines the rate of flow of liquid through the siphon, may be adjustable by pushing or pulling or rotating the closed sleeve, relative to the upright inner tube.

Preferably means is provided to secure the closed sleeve in any desired position relative to the upright inner tube.

In a cistern embodying the invention the siphon is initiated when the level of liquid in the cistern drops below the lower end of the external branch of the siphon, and terminates when the float chamber is empty.

The invention also lies in a siphon device comprising, a first branch comprising an inner upright tube adapted to be fitted in a reservoir so as to extend upwardly therewithin and externally therebelow, and a second branch which is formed by a closed sleeve which is fitted over that part of the upright inner tube which will in use extend upwardly within the reservoir so that a first passage exists from the top to bottom of the sleeve between the inside thereof and the outside of the upright inner tube, wherein a first gap exists between the open end of the inner tube and the upper closed end of the sleeve, and a second gap is formed by spacing the lowermost edge of the sleeve from the base of the reservoir when the device is fitted therein, so that when the siphon is initiated, liquid can pass through the second gap into and up the sleeve between it and the inner tube and thereafter down the tube to exit through the lower end thereof The rate of flow of liquid through such a siphon device may be adjustable by moving the sleeve relative to the inner tube.

The sleeve is preferably securable in position, to maintain the selected flow rate througli the siphon tube.

Axial movement of the sleeve may be achieved by rotating it relative to the inner tube.

The flow rate is preferably adjustable after installation of the siphon in a reservoir The invention also lies in a liquid reservoir when fitted with a siphon device as aforesaid.

The invention will now be described by way of example with reference to the accompanying drawings, in which:-Fig. I is a side view partly in cross section of a cistern and float controlled valve, containing a float chamber which communicates with the cistern via a small hole, Fig. 2 is a similar view in which the hole is replaced by a siphon tube, Fig. 3 is a similar view showing an alternative and new siphon arrangement in place of the simple siphon of Fig 2, Fig. 4 is a side view in cross section through the siphon arrangement of Fig. 3, to a larger scale, Fig. 5 is a side view of the lower end of the inner part of the Fig. 3 and 4 siphon arrangement, Fig. 6 is a partly sectional side view of the complete inner part of the siphon arrangement of Figs. 3 and 4, Fig. 7 is a side view of the external sleeve which fits over the inner part of the siphon arrangement of Fig. 6, Fig. 8 is a perspective view of the inside of the sleeve of Fig. 7, Fig. 9 is a cross section sectioned end view of the lower end of the sleeves of Figs. 7 and 8 Fig 10 is a cross section of an alternative siphon arrangement showing the roof of the shroud domed, and without one branch of the siphon protruding into the shroud, and Fig 11 is a similar view to Fig 10 where one protruding branch of the siphon is extended below the base of the chamber to form part of the domed roof of the shroud.

Description of the drawings.

Fig. I shows the known arrangement of float controlled valve 10 mounted to a water cistern, one wall of which is shown at 12. The valve inlet 14 is supplied with water under pressure which leaves the valve via outlet 16 when the float 18 drops below the position shown.

This is achieved in known manner by attaching the float 18 to one end of an arm 20 which is pivotally joined to the valve 10 at its other end. The float is carried by a rod 22 and its height relative to the valve 10 is adjustable by adjusting the position at which the rod 22 is fixed to the arm 20.

The pivoted end of the arm 20 includes an upstanding actuator 24 which closes the valve by closing a vent 26 ahead of piston 28.

The float is surrounded by a float chamber or catchpot 30 which comprises an upwardly open cup-like reservoir having a small hole 32 in its base 33, through which water can enter and leave the chamber.

The chamber 30 is carried at the end of a fixed support arm 34 which at the other end is secured to the cistern wall 12, typically by a flange sandwiched between the wall 12 and the valve 10. A mounting made up of plates 36 and 37 secures the chamber 30 to the arm 34, and the mounting above the mounting allows the height of 30 to be adjusted relative to the cistern.

The height of 30 is selected so that shortly before the water reaches the height at which the cistern is deemed to be full it will overflow into the chamber 30 and lift the float 18 and arm 20 in the direction of arrow 38 to close the valve.

When the wc is flushed, the water level in the cistern immediately drops, but because the water level in the chamber 30 can only fall at a rate governed by the size of the hole 32, the float 18 and arm 20 will not drop immediately so that the valve 10 remains closed until sufficient water has left via 32 to allow the float to drop. This delay can be a few seconds, and by this time the cistern will have emptied and the emptying siphon will have broken, so that water will have ceased to leave the cistern.

Consequently by delaying the dropping of the arm 20 in the direction of arrow 39, and the opening of the valve 10 by those few seconds, so all the water which subsequently enters the cistern from valve 10 will be retained therein, ready for the next flush.

As mentioned previously, problems arise if the hole 32 becomes partly (or wholly) blocked, and the present invention seeks to overcome such problems.

The principle of the invention is shown in Fig. 2 in which an inverted U-tube is fitted to the chamber 30 in place of the hole 32. The longer branch 42 of the tube 4Oextends through the base 33 of the float chamber 30, and the open end of the shorter branch 44 terminates just above the base 33. The crown of the bend is located above the level to which water will normally rise in the cistern, as denoted by dotted line 46 in Fig. 2.

As the cistern fills but the water level in 30 remains below that at which the float 18 closes the valve the rising water level in the cistern does not affect the water level in 30. However as it rises above the chamber 30 the latter rapidly fills, and valve 10 is firmly closed.

At this point the siphon branches 42 and 44 will be at least partly filled with water, typically with a bubble of air trapped in the region of the crown of the U-bend. When the WC is subsequently flushed, the water level, in the cistern falls rapidly and will tend to draw water out of 42. This should dislodge the air bubble in the crown region of 40 so that it travels down the branch 42 and escapes, drawing water from 30 via 44 in doing so, and establishing a siphon. This continues to empty 30, causing 18 to drop and open valve 10, to refill the cistern. ii

By using a small bore tube for the siphon tube 40, the flow can be slow enough to introduce sufficient delay in the opening of 10 so that it only opens after the flow of water from the cistern has finished. However it has been found that the very small bore required to introduce this delay can be too small to reliably purge the tube of the air initially trapped therein, so preventing the siphon from striking.

In order to overcome this, a new type of siphon is proposed, as incorporated into Fig. 3, in which the U-bend 40 is replaced by a central vertical tube 48 and the branch 44 is replaced by a sleeve 50 which is closed at its upper end, and which is spaced from the tube 48. A gap is left between its lower end 52 and the base 33 of the float chamber Spacers in the form of wings 54, 56 space the sleeve 50 from 48, and a foot 57 spaces the lower open end 52 of the sleeve 50 from the base of the chamber.

Adjusting the height of 57 increases or decreases the size of the gap, and therefore will alter the rate of flow of water through the siphon, once truck. This in turn alters the delay before the float 18 drops and opens the valve 10.

In order to ensure that air is fully purged from the siphon, a shroud defining an open ended cup-shaped housing 58 is fitted to the underside of 33 so as to surround the protruding end of the tube 48. As the cistern fills water rises in and fills housing 58. When the cistern is emptied and the water level falls below the base 33, the water in 58 seeks to follow the rest of the water in the cistern. However it can only do so by pulling water through tube 48. Since the relative volumes of 48 and 58 are so disparate any air at the top of 48, trapped in the crown of sleeve 50, will be pulled into and down 48 so as to be released into 58, where it is trapped, outside tube 48, so ensuring a continuous column of water in 48 and 50, and reliably striking a siphon which empties float chamber 30 before collapsing.

As the cistern fills, eventually the rising level of water in 58 traps any air below 33 around the protruding tube 48. As the level continues to rise, Hydrodynamic pressure forces air and water up the tube 48 and down the annular space between it and the sleeve 50, to escape into the chamber 30 through the gap at the lower end 52 of the sleeve 50. A small volume of air may remain at the top of 50, but this will be discharged subsequently, as described above, as soon as the cistern starts to empty with the next flush of the WC.

In order to assist in the escape of bubbles of air from the lower end of 48, the lowermost end face 60 is angled at an acute angle to the length dimension of 48 (i.e. the axis of the tube 48). Bubbles therefore tend to roll up the end face and leave 48 to rise up to the underside of 33 within shroud 58, instead of clinging to the underside of 48 where they could track back up into tube 48.

It is of course essential that air trapped in 58 will enter 48 ahead of any water rising up within 58 as the cistern refills. To this end at least one slit 62 (and preferably two diametrically opposite slits) is provided in the wall of the tube 48 between its lowermost end 60 and the base 33 of the chamber The width of the (or each) slit is selected so that bubbles of air (which are encased in a film of water) travelling down the tube 48 do not burst into the slit (or slits) due to the surface tension force of the water within the bubble encasing film, but as a consequence travel to the bottom of the tube 48 to escape and collect as "free air" within 58. However, when the flow is reversed during refilling of the cistern, the free air can pass freely through the slit (or slits) 62 ahead of the water, since the latter is forced to enter the tube 48 through the hole in the lower end face 60 since surface tension prevents it from entering 48 through the slit or slits 62.

Adjustments of the flow rate of water into and through the siphon arrangement of 48 and 50 can be achieved if the sleeve 50 is pulled up, or pushed down, to adjust the size of the gap. Preferably it is secured in place when the desired gap is achieved.

Alternatively and preferably, as better shown in the enlarged scale view of Fig. 4, the lower end 52 of sleeve 50 is, like the lower end face of tube 48, angled relative to the length dimension or axis of the sleeve 56, and therefore angled relative to the axis of 48. After pushing the sleeve 50 down into contact with foot 57 and rotating it one way or the other, (see arrows 59, 61), the engagement of the inclined end face 52 with the foot 57 causes the gap to be increased or decreased depending on the direction of rotation. In fact, by careful selection of the angle which the end face 52 makes with the tube 48, only 90 of rotation of 50 relative to 48 will give all the adjustment necessary to allow the siphon flow rate to be fine-tuned after installation. The rotation of the sleeve 50 can be restricted to approximately 90u by providing two diametrically opposed inwardly directed wings on the inside wall of 50 which together with the wings 54, 56, centre the sleeve 50 on the tube 48. Engagement of wings on the sleeve 50 with those on the tube 48 restrict rotation to approximately 90 Fig. 5 Shows the lower end of 48 and the diametrically opposed wings 54, 56 and shroud 58, above and below the base 33 respectively.

Fig. 6 Shows the inside of shroud 58 and the inclined end face 60 of tube 48, and one of the two diametrically opposed slits 62, to a larger scale than in Fig. 3.

Fig. 7 Illustrates the angle A between the end face 52 and what would be its end face if it were "square" to the sleeve 50. The acute angle between the end face 52 and the axis of 48 (and therefore 50) is (90_A)u Figs. 8 and 9 show the internally directed wings 66, 68 which co-operate with wings 54, 56 to centre the sleeve 50 on the tube 48.

As shown in Fig. 9 a grub screw 70 may be threaded in an internally threaded bore 72 through the wall of 50, which after the latter has been rotated into the desired position relative to 48 (and 56) can be screwed into engagement with 48 to anchor the sleeve 50 in place.

Fig. 10 shows how the protruding part of tube 48 can be dispensed with when the Water Saving Device is used in a cistern that is fitted with a fast discharge mechanism. The domed roof 73 of the shroud 58 channels air up the tube 48. The shroud is incorporated into the base 33 of the chamber 30.

Fig II shows the shroud 58 lowered, increasing the length of tube 48 assisting the siphon flow (once stuck) when emptying chamber 30 and how the domed roof 73 of the shroud is separated from the chamber base 33 The float controlled valve described herein can be used for controlling the flow of any liquid -not necessarily water.

The improved design of siphon disclosed herein is not restricted to use in WC cisterns, but may be employed to control the flow of liquid out of containers or reservoirs, such as are employed to supply predetermined volumes of liquid in a dosing system.

Claims

1. A cistern having a delayed action float controlled liquid inlet valve which includes a float chamber in the cistern within which the valve float is located, which chamber fills with liquid in use to cause the valve float to rise and close the valve, and in which a siphon tube is provided for emptying the chamber when the cistern is emptied and one branch of the siphon tube extends externally of the float chamber, to a point which is enclosed within a shroud and is below the base of the float chamber.

2. A Cistern as claimed in Claim 1 wherein the lower end of the said one siphon branch communicates with an inverted cup-shaped shroud and the siphon tube protrudes into the shroud.

3. A cistern as claimed in Claim 2 wherein the end face of the lower external end of the one siphon branch extends at an acute angle to the axis of the tube, so that the lower external end thereof is not square to its axis, to assist in discharging air bubbles which reach the external end of the branch.

4. A cistern as claimed in Claim 1 wherein the said one branch of the siphon tube extends through the base of the float chamber and the protruding part has at least one narrow slit in the wall thereof which extends over some or all of the length of the protruding part.

5. A cistern as claimed in Claim 4 wherein the width of the slit is selected so that the surface tension of liquid in the protruding part of the siphon tube prevents air in the liquid which has formed bubbles from leaving via the slit, thereby forcing the air bubbles to pass to the bottom of the protruding part before they can leave whereas when the reservoir is empty and there is no liquid in the protruding part, air trapped below the float chamber as the cistern refills, is free to pass through the slit into the siphon tube, so that air trapped below the chamber is forced into the siphon tube ahead of a rising liquid level

6. A cistern as claimed in Claim I wherein the siphon is an inverted U-tube one branch of which protrudes through the base of the float chamber and has at least one slit in the wall thereof where it extends below the base of the float chamber, the end face of the protruding part is not square to the axis of the protruding part but lies at an acute angle thereto, and the protruding part is surrounded by a shroud which creates with the underside of the float chamber an inverted cup-shaped enclosure in which any escaping air bubbles will accumulate and from which the air will be displaced via the slit into the siphon tube ahead of liquid rising up in the enclosure as the cistern refills.

7. A cistern as claimed in any of claims I to 6 wherein the float chamber serves as a catchpot which is emptied by the siphon each time the cistern is emptied thereby generating a constant delay before the inlet valve is opened.

8. A cistern as claimed in any of claims 1 to 7 wherein the siphon flow rate is adjustable to allow the delay in the valve opening to be adjusted.

9. A cistern as claimed in claim 8 wherein the siphon flow rate is adjustable after installation of the valve and float chamber in the cistern.

-

10. A cistern as claimed in claim 7, 8 or 9 wherein the cistern is emptied through a second siphon and once emptied liquid cannot exit via the second siphon until flow through the latter is initiated.

11 A cistern as claimed in claim I wherein the siphon tube in the float chamber comprises an inner upright tube which extends through and above and below the base of the float chamber and upwardly from the base to a point higher than the upper edge of the float chamber, and the other branch of the siphon is created by fitting a closed sleeve over the upstanding end of the upright inner tube so that a passage exists from the top to bottom of the sleeve between the inside thereof and the outside of the inner tube, and a first gap exists between the upper open end of the inner upright tube and the upper closed end of the sleeve, and a second gap exists between the lowermost edge of the sleeve and the base of the float chamber so that when a siphon is initiated liquid can pass through the second gap into and up the sleeve between it and the tube and thereafter down the upright tube, to discharge through the lower end thereof.

12. A cistern as claimed in claim 11 wherein the size of the second gap which determines the rate of flow of liquid through the siphon, is adjustable by pushing or pulling or rotating the closed sleeve, relative to the upright inner tube.

13. A cistern as claimed in claim 12 wherein means is provided to secure the closed sleeve in any desired position relative to the upright inner tube.

14. A cistern as claimed in any of claims I to 13 wherein, in use, the siphon is initiated when the level of liquid in the cistern drops below the lower end of the external branch of the siphon, and terminates when the float chamber is empty.

15. A siphon device comprising a first branch comprising an inner upright tube adapted to be fitted in a reservoir so as to extend upwardly therewithin and externally therebelow, and a second branch which is formed by a closed sleeve which is fitted over that part of the upright inner tube which will, in use, extend upwardly within the reservoir so that a first passage exists from the top to bottom of the sleeve between the inside thereof and the outside of the upright inner tube, wherein a first gap exists between the upper open end of the inner tube and the upper closed end of the sleeve, and a second gap is formed by spacing the lower most edge of the sleeve from the base of a reservoir the device is fitted therein so that when the siphon is initiated, liquid, can pass through the second gap into and up the sleeve between it and the inner tube and therafter down the tube to exit through the lower end thereof

16. A siphon device as claimed in claim 15 wherein the rate of flow of liquid therethrough is adjustable by moving the sleeve relative to the inner tube.

17. A siphon device as claimed in claim 16 wherein the sleeve is securable in position, to maintain the selected flow rate through the siphon tube.

18. A siphon device as claimed in claim 17 wherein axial movement of the sleeve is achieved by rotating it relative to the inner tube.

19. A siphon device as claimed in any of claims 15 to 18 wherein the flow rate is adjustable after installation of the siphon in a reservoir.

20. A shroud as claimed in claim I wherein the lower end of the siphon does not protrude into the shroud when the cistern is fitted with a fast discharge mechanism.

21. A shroud as claimed in claims I and 20 wherein the shroud has a domed roof to assist the channelling of air into the inner upright tube of the siphon.

22. A shroud as claimed in claims 1, 20 and 21 is separated from the chamber by increasing the length of the inner upright tube, below the base of the chamber.

23. A liquid reservoir when fitted with a siphon device as claimed in any of claims 15 to 22.

24. A cistern having a delayed action float controlled inlet valve constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.

25. A siphon device constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS 2-0 1. A float chamber is provided within a cistern which cistern is controlled by a delayed action float controlled liquid inlet valve, within which the valve float is located in the chamber, which chamber fills with liquid in use to cause the float to rise and close the valve, and in which a siphon tube is provided for emptying the chamber when the cistern is emptied and one branch of the siphon tube extends externally of the chamber, to a point which is enclosed within a shroud and is below the base of the float chamber.

2. A float chamber as claimed in Claim 1 wherein the lower end of the said one siphon branch communicates with an inverted cup-shaped shroud and the siphon tube protrudes S..

into the shroud. *. *5

* S. S * . 3. A float chamber as claimed in Claim 2 wherein the end face of the lower external end of the one siphon branch extends at an acute angle to the axis of the tube, so that the lower external end thereof is not square to its axis, to assist in discharging air bubbles which reach the external end of the branch.

4. A float chamber as claimed in Claim I wherein the said one branch of the siphon tube extends through the base of the float chamber and the protruding part has at least one narrow slit in the wall thereof which extends over some or all of the length of the protruding part.

5. A float chamber as claimed in Claim 4 wherein the width of the slit is selected so that the surface tension of liquid in the protruding part of the siphon tube prevents air in the * I liquid which has formed bubbles from leaving via the slit, thereby forcing the air bubbles to pass to the bottom of the protruding part before they can leave whereas when the reservoir is empty and there is no liquid in the protruding part, air trapped below the float chamber as the cistern refills, is free to pass through the slit into the siphon tube, so that air trapped below the chamber is forced into the siphon tube ahead of a rising liquid level.

6. A floaç chamber as claimed in Claim 1 wherein the siphon is an inverted U-tube one branch of which protrudes through the base of the float chamber and has at least one slit in the wall thereof where it extends below the base of the float chamber, the end face of the protruding part is not square to the axis of the protruding part but lies at an acute angle thereto, and the protruding part is surrounded by a shroud which creates with the underside of the float chamber an inverted cup-shaped enclosure in which any escaping air bubbles :.:. will accumulate and from which the air will be displaced via the slit into the siphon tube ahead of liquid rising up in the enclosure as the cistern refills. * . * I..

7. A float chamber as claimed in any of claims I to 6 wherein the float chamber serves as a catchpot which is emptied by the siphon each time the cistern is emptied thereby generating a constant delay before the inlet valve is opened.

8. A float chamber as claimed in any of claims 1 to 7 wherein the siphon flow rate is adjustable to allow the delay in the valve opening to be adjusted.

9. A float chamber as claimed in claim 8 wherein the siphon flow rate is adjustable after installation of the valve and float chamber in the cistern.

* 2-2- 10. A float chamber as claimed in claim 1 wherein the cistern is emptied through a second siphon and once emptied liquid cannot exit via the second siphon until flow through the latter is initiated.

II. A float chamber as claimed in claim I wherein the siphon tube in the float chamber comprises an inner upright tube which extends through and above and below the base of the float chamber and upwardly from the base to a point higher than the upper edge of the float chamber, and the other branch of the siphon is created by fitting a closed sleeve over the upstanding end of the upright inner tube so that a passage exists from the top to bottom of the sleeve between the inside thereof and the outside of the inner tube, and a first gap exists :*. between the upper open end of the inner upright tube and the upper closed end of the sleeve, *. and a second gap exists between the lowermost edge of the sleeve and the base of the float chamber so that when a siphon is initiated liquid can pass through the second gap into and up the sleeve between it and the tube and thereafter down the upright tube, to discharge :. through the lower end thereof * S S...

12. A float chamber as claimed in claim 11 wherein the size of the second gap which determines the rate of flow of liquid through the siphon, is adjustable by pushing or pulling or rotating the closed sleeve, relative to the upright inner tube.

13. A float chamber as claimed in claim 12 wherein means is provided to secure the closed sleeve in any desired position relative to the upright inner tube.

14. A float chamber as claimed in any of claims I to 13 wherein, in use, the siphon is initiated when the level of liquid in the cistern drops below the lower end of the external branch of the siphon, and terminates when the float chamber is empty.

15. A siphon device as claimed in claims 1 to 12 and 14 comprising a first branch comprising an inner upright tube adapted to be fitted in a reservoir so as to extend upwardly therewithin and externally therebelow, and a second branch which is formed by a closed sleeve which is fitted over that part of the upright inner tube which will, in use, extend upwardly within the reservoir so that a first passage exists from the top to bottom of the sleeve between the inside thereof and the outside of the upright inner tube, wherein a first gap exists between the upper open end of the inner tube and the upper closed end of the sleeve, and a second gap is formed by spacing the lower most edge of the sleeve from the base of the reservoir chamber the device is fitted therein so that when the siphon is initiated, liquid, can pass through the second gap into and up the sleeve between it and the inner tube and therafier down the tube to exit through the lower end thereof; which end protrudes into a shroud.

20. A shroud as claimed in claim 1 wherein the lower end of the siphon does not protrude into the shroud when the cistern is fitted with a fast discharge mechanism.

21. A shroud as claimed in claims 1 and 20 wherein the shroud has a domed roof to assist the channelling of air into the inner upright tube of the siphon.

:*. 22. A shroud as claimed in claims 1, 20 and 21 is separated from the chamber by increasing the length of the inner upright tube, below the base of the chamber. C. **

* S. S * * 23. A liquid reservoir when fitted with a siphon device as claimed in any of claims 15 to 22. S. S. * .* * S..

24. A float chamber within a cistern having a delayed action float controlled inlet valve constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.