GB2271582A - Siphon-protected fluid inlet valve waste preventer for a W.C. cistern - Google Patents

Abstract

A fluid inlet valve waste preventer for incorporation in a fluid discharge system comprises a discharge valve (2) to be mounted inside, and to discharge through an outlet in the bottom of, a first cistern (1), a second cistern (9) containing a float (8) co-operating with an inlet valve (5) to control the level (16, 17) of the fluid in both the first and second cisterns and means to empty the second cistern (9) by siphonic action. The means to empty the second cistern (9) may be, for example a siphon-inducing device activated by fall in the fluid level (16) in the first cistern (1). <IMAGE>

Description

SIPHON PROTECTED FLUID INLET VALVE This invention relates to the protection of liquid storage systems against the eventuality of continued ongoing fluid loss and is primarily intended to work in conjunction with light action, easily operable, fast flowing cistern or tank outlet valves. It is particularly, although not exclusively, applicable to being used for protecting the water inlet valve of domestic toilets or W. C.'s fitted with non-siphon type outlet valves.

Flushing toilets have been in existence for a great many years and the W. C. in one form or another is commonplace in every modern home.

With the conventional modem low flush or close-coupled toilet cistern, the arrangement for achieving the flush is either a siphon (which is mandatory for the U.K.) or a 'non-siphon' type discharge valve for the majority of W. C. installations elsewhere in the world.

Discharge valves of the non-siphon type have a number of distinct advantages over the siphon and, on account of their better performance in terms of greater hydraulic efficiency and requiring less water for achieving satisfactory flushing, they have become the obvious choice in parts of the world where water conservation is of importance. Generally their reliability is good and waste due to leakage is very small. However, the integrity of this type of valve is mainly dependant on seals and in the event of wear taking place or a malfunction, continued water loss would occur and could become very significant before being detected. In fact it was the likelihood of this situation occurring which caused the relevant statutory U.K. water bye-laws to be established, making it a compulsory requirement that all W.C. installations be fitted with a flushing device which safeguards against continued water loss. The siphon, with its "invert", i.e. an inverted 'U' tube or its equivalent, set above the maximum water level is such a device and it has been used in the U. K. for a great many years.

Siphonic flushing devices can, however, vary considerably in performance and the majority do not operate satisfactorily below a medium water level setting. Most W. C.'s ofthis type require quite a lot of water to produce an effective flush, they can be slow to discharge and in some cases their efficiency can be significantly impaired by small reductions in the set water level in the cistern. In addition there are some flush operating mechanisms which, particularly at certain water level settings, require considerable effort and speed of actuation. This precludes operation by certain disabled persons, some old people and most young children.

With legislation in the U. K. moving to progressively reduce the amount of water for flushing, major configurational changes and improvements will be required to achieve satisfactory performance from future siphonic flushing devices.

According to the present invention there is provided a fluid inlet valve waste preventer for incorporation in a fluid discharge system, the installation comprising a discharge valve to be mounted inside and to discharge through an outlet in the bottom of a first cistern, a second cistern containing a float co-operating with an inlet valve to control the level of fluid in both the first and second cisterns, and means to empty the second cistern by siphonic action.

Normally one of the cisterns will be fitted inside the other and the invention will be more specifically described below with reference to an arrangement in which the discharge valve is in the bottom of a main cistem and the float is in an inner cistern within the main cistern but it will be appreciated that the specific embodiments described may be applicable to other first and second cistern arrangements.

The siphonic action may be caused directly by suction created by fluid discharging through a narrowing in the outlet or by a siphon-inducing device operated by fall in the fluid level in the main cistern.

The fluid, particularly for discharge systems of the W. C. type will, of course, normally be water and the invention will hereafter be described with reference to water for convenience.

In a preferred embodiment the inlet valve has a dual flow operation whereby the main and inner cisterns are filled separately. Thus unintended loss of water from the main cistern will not prevent filling of the inner cistern followed by closure of the inlet valve by the float.

In another preferred embodiment the siphon-inducing device is a discharge or siphon duct with its entrance in and adjacent to the bottom of the inner cistern and its exit uppermost to form a siphon 'invert' with the top of a suction column in the main cistern, the lower end of the column being below the bottom of the inner cistern. Thus with the fast fall in water level in the main cistern when the discharge valve is opened, sufficient suction and flow is created within the inner cistern siphon duct and the suction column to siphon and empty the inner cistern.

Conveniently the suction column can be provided by a bottomless sleeve surrounding the inner cistern whereby the column is defined between the outer side of the wall of the cistern and the inside of the wall of the sleeve and the siphon duct can be defined between the inside wall of the inner cistern and a downward extension from the top of the sleeve which extends into the inner cistern to form the entrance to the siphon duct adjacent the bottom of the inner cistem.

In one of the preferred embodiments of the siphon invert arrangement, there is connected at the head of the suction column above the siphon "invert" a vent tube for directly connecting the head of the column to the discharge outlet so that the column is vented continuously, except for when the valve is discharging and the vent therefore blocked off by water flow in the outlet pipe. Alternatively, the head of the column above the "invert" can have an air vent hole or port which could be either float or diaphragm operated to seal off the ingress of air during the operating mode to prevent depletion of the suction.

Thus the invention provides a discharge system which enables a high performance direct type discharge or non-siphon valve to be used whilst incorporating the necessary protection devices for safeguarding against failure or malfunction of the main valve.

The manner by which the invention achieves its preferred functions is best explained by a summary of the principle of operation. During filling of the cistern, fluid flows from the inlet valve at different rates, both into a main and inner cistern wherein it is so arranged that the rate of filling of the main cistern exceeds that of the inner cistern by a considerable margin and as such, when the main cistern level has been achieved, water overflows into the inner cistern which quickly raises its level causing the float to rise and shut off the inlet valve.

On operation of a push button or similar actuating device, the outlet or discharge valve is opened and immediately the main cistern starts to empty, but initially the inlet valve remains closed. However, soon afterwards due to a fall in level in the main cistern, suction is created at the top of the suction column causing water to be siphoned from the inner cistern into the main cistern via the suction column. This action continues until both the inner cistern and main cistern are empty, following which refilling commences. In most configurations generally both cisterns will empty at the same time or the inner cistern will empty slightly sooner.

In the event of a loss of water due to leakage from the main cistern, the inner cistern would be unaffected and thus the inlet valve would remain closed. With a gradual fall in water level in the main cistern, insufficient suction would be created to siphon water from the inner cistern. This is due to the venting of the suction column, by air entering through a vent hole or via a tube. If the water level in the main cistern falls too low, a point is reached at which insufficient suction can be created to siphon the water from the inner cistern and thus the inlet valve will remain closed.

Thus only the contents of the cistern (usually 7 litres) would be lost before it became necessary to remedy the fault.

As already stated in the foregoing, the main objective of this invention is to provide a protection system for W. C.'s wliich enables non- siphon type valves to be used for flushing, and yet incorporating a similar siphon means so as to safeguard against water loss.

Although not exclusive to aíy specific type of non-siphon valve, the invention is particularly suited for use with the type of valve defined by International Patent Application PCT/GB 92/01623, publication number W093/05247.

For a better understanding of the invention some embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a general diagrammatic arrangement of a cistern fitted with a direct discharge valve and an inlet valve with a water waste protection module; Figures 2, 3 and 4 show the waste protection module in more detail, Figure 2 being a plan view and Figures 3 and 4 being part-sectional front and side views respectively; Figure 5 is another diagrammatic arrangement showing an alternative embodiment of the invention; Figure 6 is a sectional view showing details of a typical discharge/ outlet valve and vent pipe connection; Figure 7 is a view along line A of Figure 6; Figure 8 is a section on line B-B of Figure 6; and Figure 9 is a similar view of Figure 1 showing a modified arrangement of the invention; Figure 1 shows a fluid storage/discharge system (a typical application for which would be the cistern of a domestic W. C.) with the discharge valve 2 fitted at the bottom of the main cistern 1 and totally immersed in water at its set level 16. Moreover, with the main cistern full, the water inlet valve 5 is shut off and held in the closed position by the float 8 which is inside the inner cistern (float chamber) 9 containing water at level setting 17, which can be either the same as that in the main cistern or marginally below.

For continuing the description of Figure 1, it will also be necessary as appropriate to refer briefly to other figures (which will be described separately and in more detail later in the text).

A bottomless sleeve 13 (Figure 4) surrounds inner cistern 9 whereby a suction column 11 is defined between the outer side of wall 9A of the cistern and the sleeve. An extension 13A from the top of the sleeve extends downwardly into the cistern to form a siphon duct 10 between itself and the inner side of wall 9A. As shown, the entrance 15 to the siphon duct 10 is defined between the bottom of the inner cistern 9 and the lower end of extension 13A. A siphon invert is thereby provided at the top of duct 10.

With the cistern 1 filled the suction column 11 contains water at the same level as in the main cistern 1 and the upper part of the column 11 contains air at atmospheric pressure as does the siphon duct 10 above the level of water 17 in the inner cistern 9. The siphon duct will thus contain water between its bottom end, entrance 15, and the level setting 17.

The means of operating the discharge valve is shown as a flexible control cable 3 (Figure 1), the other end of which is attached to a push button, handle or lever (not shown) conveniently positioned on the outside of the main cistern.

On operation of the discharge valve 2, water flows from the main cistern, through the valve and is discharged from the outlet pipe 4, after which in the case of the W. C., it flows into the toilet pan to provide the flush.

The water level in the main cistern rapidly falls and in doing so causes an initial fall in the column water level and water to flow from the bottom of the sleeve 13. At the top of the sleeve, a vent port 12 and connecting vent pipe 28 leading to side connector 27 and port 26 in the outlet pipe 4 (see Figure 6) are closed off by water in the outlet pipe, which is only present for the duration of discharge. Normally the outlet pipe is empty and allows the top of the sleeve 13 to freely vent to atmospheric pressure. Thus during discharge there is an enclosed volume at the top of the sleeve between the two water levels 16 and 17 so that water cannot flow freely from the bottom of the sleeve.As the water level in the main cistern 1 falls, the difference in water levels in the sleeve 13 and the main cistern increases creating a substantial suction at the top of the sleeve adjacent vent port 12. This suction causes a small amount of water to enter the lower end of the connecting pipe 28 at the valve connecting port 26 and for water to be rapidly drawn from the inner cistern through the siphon duct 10, over the invert 21 and into the column 11 so that from thereafter water is quickly siphoned from the inner cistern until it is empty, i.e. the level reaches the bottom of the siphon duct 10 adjacent to entrance 15.

In the preferred arrangement the sizes and parameters are chosen for the inner cistern, siphon and sleeve which enable a single optimum unit to function at all practical water level settings and ensure that the inner cistern is emptied before the main cistern water level has fallen below the bottom of the sleeve 13.

As the water level falls in the inner cistern 9, the float 8 descends and, in doing so, the inlet valve 5 opens and delivers water both to the main supply pipe 6 and the pilot feed 7. Float plate guide 50 (Figure 3) maintains the float in the desired path. The flow rates are so proportioned that the supply pipe 6 will always fill the main cistern by an order of magnitude faster than the inner cistern is filled by the pilot feed 7 (Figure 1). Invariably the level in the main cistern rises until it overflows into the inner cistern, whereupon, the level in the inner cistern rapidly rises, causing the control float 8 to close off the inlet valve 5.The separate supply to the inner cistern is provided as a safeguard in the event of a condition arising whereby water could escape from the cistern at a rate equal to, or in excess of, that which can be supplied by the main supply pipe 6 and thus the water level in the main cistern would not reach the inner cistern and therefore there would be no supply to the inner cistern to close the inlet valve.

During refilling water enters the column 11 via the open bottom of sleeve 13 and the level in the sleeve rises at the same rate as that in the main cistern. Air above the water in the sleeve is very slightly compressed and vents freely via the port 12, vent pipe 28, side connector 27 and port 26 into the outlet pipe 4 (which contains air at atmospheric pressure).

During the early stages of refilling some air can also escape from the siphon duct entrance 15 due to there being only a small resistance due to the very low level of water in the inner cistern initially.

The main reason for venting the sleeve is to ensure that in the event of substantial leakage from the main cistern, the sleeve would not siphon water from the inner cistern, and thus the inlet valve would remain closed so that when the main cistern was empty no further water could be lost.

Of the possible vent valves suitable for use with this invention, for example, flow-sensing float-operated vent shut off, differential pressure diaphragm-operated vent shut off and water interlocking vent pipe shut off, the latter is preferred and the most reliable. Tn the description of the embodiment depicted by Figure 1, the function and operation of the water interlocking vent pipe shut off system has been described.

Figures 2, 3 and 4 show three views of the inner cistern 9, with a constant head feed hopper, control float and vent pipe connection, wherein feed water 7 from the inlet pilot valve enters a header trough 30 and then flows through floating pintle flow control valves 18 into the inner cistern below. Excess water flows over a weir 20 which maintains a constant head of water to the control valves. The float 8 is attached to a pilot arm 32 via a swivel connection 31.

An alternative arrangement for the inner cistern water feed is to replace the header trough and pintle valves by a deflection guard to ensure that only the feed water 7 from the pilot inlet valve enters the inner cistern directly. Any excess water leaking from the back flow preventer on top of the inlet valve and the connection to the supply pipe 6 would thus be deflected away from the inner cistern and into the main cistern.

Figures 6, 7 and 8 show details of a side entry vent connection to the discharge valve outlet 4. Tn the unoperated mode, the outlet pipe 4, side connector 27 and vent pipe 28 are all empty and the top of the suction column 11 freely vented. On operation of the discharge valve, the outlet pipe 4 is filled with water and as the suction in the suction column 11 increases water is drawn through the aperture 26 into the connector 27 and bottom of the vent pipe 28 until a level is reached which balances the suction at the top of the suction column.

When the cistern is empty the outlet pipe 4 is also empty and irrespective of whether the column 11 or siphon duct 10 retain a residual suction, water will flow from the bottom of the vent pipe 28 through the side connector and aperture 26 back into the outlet pipe 4. The aperture is adequately proportioned to vent under all conditions except during discharge.

An important design consideration determining aperture shape and dimensions is the effect breaking into the outlet pipe 4 at this point would have on performance and it is therefore necessary to determine the proportions which would minimise the effect. This is however, a matter of routine for the skilled man of the art.

There are a number of alternative configurations and variations of the invention. Typically these consist of separating the suction column from the inner cistern and connecting the top of the suction column to the inlet duct via a pipe or extension of the inlet siphon duct and separating and re-positioning the inner cistern and float from the inlet valve wherein the inlet valve and float are connected by a conventional float arm and the pilot feed from the inlet valve to the inner cistern is connected via an extended small bore pipe.

The arrangement shown in Figure 5 has a separate suction column 11 and siphon invert 21.

Suction column 11 is connected to invert 21 by a suction inducing pipe 41. One leg of the siphon is within inner cistern 9 and has entrance 15 at its lower end. The other leg is a combined siphon down leg and vent pipe 40. Thus discharge of water from cistern 9 under suction created by a fall in the water level in column 11 takes place directly into discharge valve 2 via pipe 40 and side connection 27. Tn this embodiment the emptying of the pilot cistern will be slower so that it continues to empty after the main cistern has emptied.

Similar suction inducing devices include a weighted float operated suction piston and a weighted float operated piston type pump - both of which are operated by the fall in water level in the main cistern and can be fitted as an alternative to the suction column 11 shown in Figure 5. The suction piston would be connected in a very similar manner to that of the suction column, with the vacuum connecting pipe 41 initiating the siphon by pulling water over the siphon invert 21 and filling the down leg 40. The piston pump type on the other hand would admit water via the connecting pipe 41 to fill the down leg and would in addition require one or more nonreturn valves.

As another alternative to the suction column in Figure 5 or similar device, suction could be created by venturi action in the discharge valve outlet pipe 4 which would have contours of the usual venturi shape. With such an arrangement water would be siphoned directly from the inner cistern via the siphon tube assembly 40 and side connection 27 into the outlet pipe 4 and there would be no other connections i.e. no suction pipe 41.

Other possible suction arrangements include a fluid ejector device wherein the discharge valve is mounted inside an inner container within the main cistern to provide the motive flow to create a vacuum in a gallery surrounding the outlet pipe for discharging the contents from the main part of the cistern via a large siphon tube. With such an arrangement the control float is situated in the 'main' cistern and thus the main cistern for this embodiment becomes the inner or pilot cistern.

Thus the invention can be configured in a number of alternative forms some of which would be very similar to certain embodiments already described above.

By re-configuring and changing the proportions of the device of Figure 1, a typical arrangement as shown in Figure 9 is achieved comprising a separate inner cistern, siphon and suction column. Moreover the size of the suction column has been increased substantially to extend the scope of the application whereby the extra capacity of the suction column 11 constitutes a vacuum reservoir and therefore providing a facility for working in conjunction with auxiliary equipment requiring a suction supply, such as double trap siphonic W. C.'s.

Figure 9 shows the siphon duct 10 with a branch connection and invert 21 wherein the suction in the column, created by the fall in water level in the main cistern during flushing, is transferred via the suction pipe 41 to the branch connection to draw water up the siphon pipe 10, over the invert 21 and into the 'down leg' 35 into the main cistern. This branch arrangement allows some flexibility in setting the water level in the main cistern without it being necessary to produce the increased suction to raise the water from the inner cistern to discharge into the top of the suction column. However, if utilising the full capacity of the suction column as a vacuum source were required, the separate down leg could be dispensed with and water drawn directly up the siphon pipe 10 and over the usual invert situated at the top of the suction column in a similar manner to that described for Figures 2, 3 and 4.

The vacuum facility for use in certain applications is achieved by unblocking and connecting suction port 34 to the equipment involved.

Claims (20)

1. A fluid inlet valve waste preventer for incorporation in a fluid discharge system, comprising a discharge valve (2) to be mounted inside, and to discharge through an outlet in the bottom of, a first cistern (1), a second cistern (9) containing a float (8) co-operating with an inlet valve (5) to control the level (16, 17) of the fluid in both the first and second cisterns and means to empty the second cistern (9) by siphonic action.

2. A waste preventer according to Claim 1, wherein the first cistem (1) is a main cistern and the second cistern (9) is an inner cistern within the main cistern.

3. A waste preventer according to Claim 1 or 2, wherein the means to empty the second cistern (9) is a siphon-inducing device activated by fall in the fluid level (16) in the first cistern (1).

4. A waste preventer according to Claim 1, 2 or 3, wherein the inlet valve (5) has a dual flow operation whereby the first cistern (1) and second cistern (9) are filled separately.

5. A waste preventer according to Claim 3 or 4, wherein the siphoninducing device comprises a discharge or siphon duct (10) with its entrance (15) inside, and adjacent the bottom of, the second cistern (9) and its exit uppermost to form a siphon invert (21) at the top of a suction column (11) in the first cistern (1), the lower end of the column (11) being below the bottom of the second cistern (9).

6. A waste preventer according to Claim 5, wherein the suction column (11) is defined between a bottomless sleeve (13) surrounding the second cistern (9) and the outside of the wall (9A) of the second cistern.

7. A waste preventer according to Claim 6, wherein the siphon duct (10) is defined between the inside of the wall (9A) of the second cistern (9) and a downward extension (13A) of the sleeve (13), the downward extension (1 3A) defining an entrance (15) to the siphon duct (10) adjacent to the bottom of the second cistern (9).

8. A waste preventer according to Claim 5, 6 or 7 wherein an air vent port is provided at the top of the suction column adjacent to the siphon invert and can be closed during discharge via the discharge valve (2) to prevent depletion of the siphon vacuum.

9. A waste preventer according to Claim 5, 6 or 7 wherein the top of the suction column (11) adjacent the invert (21) is connected directly to the discharge valve outlet (4) by a vent tube (28) whereby the column (11) is vented continuously except during discharge via the discharge valve.

10. A waste preventer according to Claim 3 or 4, wherein the siphoninducing device (11, 41) is a suction column (11) outside the second cistern (9), the column (11) being connected to the top of the second cistern (9) via a pipe (41) and a siphon invert (21).

11. A waste preventer according to Claim 10, wherein the second cistern has a discharge tube (35) to discharge via invert (21) into the first cistern (1) and thence to the discharge valve (2).

12. A waste preventer according to any one of Claims 3 to 10, wherein the second cistern discharges to a side entry connection (27) to the discharge valve (2) via a discharge tube (40).

13. A waste preventer according to any one of Claims 4 to 12, wherein the dual flow supply from inlet valve (5) comprises a pipe (6) to supply the first cistern (1) and a pilot feed (7) to supply the second cistern (9), the supply pipe and pilot feed being dimensioned so that the first cistern (1) is filled faster than the second cistern (9).

14. A waste preventer according to any preceding Claim, wherein the second cistern (9) is supplied via a constant head feed hopper (30) with floating control valves (18).

15. A waste preventer according to any one of Claims 10 to 14, wherein the suction column (11) is of sufficient size to provide a vacuum reservoir to operate auxiliary equipment.

16. A waste preventer, according to Claim 14, in which the auxiliary equipment is for a double trap siphonic W. C..

17. A fluid inlet valve waste preventer substantially as hereinbefore described with reference to and as shown in Figures 1 to 4 of the accompanying drawings.

18. A fluid inlet valve waste preventer substantially as hereinbefore described with reference to and as shown in Figure 5 of the accompanying drawings.

19. A fluid inlet valve waste preventer substantially as hereinbefore described with reference to and as shown in Figures 6, 7 and 8 of the accompanying drawings.

20. A fluid inlet valve waste preventer substantially as hereinbefore described with reference to and as shown in Figure 9 of the accompanying drawings.