GB2324544A - A flush control system for a W.C. cistern - Google Patents

Abstract

A flush control system (10) has support brackets (11) for mounting the system (10) on a front wall of a W.C. cistern within the cistern. A control receptacle (20) has a control lever (21) connected by a control line (22) with an operating knob (23). The lever (21) is also connected by a suspension line (24) to a lower receptacle within the cistern. A flexible pipe (26) is connected between a syphon (3) of the cistern and the control receptacle (20). When the cistern is flushed, a needle valve which is provided at the end of the pipe (26) in the control receptacle (20) controls drainage of water from the control receptacle (20) to break the syphon and stop the flushing. Adjustment of the control knob (23) adjusts the needle valve to control the rate of drainage of water from the control receptacle (20) and thus the length of the flush and volume of water flushed from the cistern.

Description

"A flush control svstem for a W.C. cistern Introduction The invention relates to a flush control system for a W.C.

cistern of the conventional type comprising a syphon.

In such cisterns the syphonic action is usually established by pushing water up and around the inverted U-shaped syphon by means of a plunger housed in the lower part of the rising leg, this part being of greater crosssectional area than the bend.

Typically, the consumptior of each flush is the entire content of the cistern plus the volume of water which enters through the ball valve while the flush is in progress.

However, in recent years there has been an increasing awareness of water conservation and it is becoming recognised that a total flush (of perhaps 12-13 litres) is not always required. To this end, various systems have been developed to vary the extent of the flush and these are described, for example, in GB2241717, GB2162214, GB2063950, GB1583601, and GB2213846. However, these arrangements are generally impractical as they involve a lengthy installation time and often require modification of the cistern tank. For example, in GB2241717 it is necessary to install a threaded spindle through the cover of the cistern water tank.

It is therefore an object of the invention to provide a flush control system which may be easily installed in a typical cistern. It is another object to provide such a control system which allows infinite adjustment of the flush volume across a wide range of volumes.

Statements of Invention According to the invention, there is provided a flush control system for a WC cistern, the control system comprising a conduit connected to the syphon to allow inlet of air to break the syphonic action, air control means to control the timing of air inlet to the conduit, and a user control means.

In one environment the user control means comprises a control handle which is connected to the air control means by a ribbon or the like which extends over the cistern water tank wall and underneath the cistern lid. This is very important as it allows installation without the necessity to drill holes or to any way modify the cistern water tank or lid. The user control means may be a handle or knob at the end of a ribbon which may be pulled to set the flush volume.

Preferably, the air control means comprises an adjustable flow restrictor. The flow restrictor is preferably based on the principle of timing access of air to the conduit as a function of flow rate of water from a control receptacle.

Preferably, the adjustable flow restrictor comprises a needle valve, the settings of which are controlled by the user control means. In one area the settings are controlled by lifting or lowering a control lever connected to one part of the needle valve. This is a very simple way of achieving infinite or stepless adjustment as the effective cross-sectional area o the conduit extends across the full range from full or uninterrupted on the one hand to completely closed at the other end of the scale.

In one embodiment, the system comprises means for resetting to a default reduced flush setting.

In one embodiment, a said resetting means comprises a water receptacle mounted at a lower level in the cistern and comprising means for pulling one part of an adjustable flow restrictor to an open position to allow water escape from the control receptacle for a reduced flush.

In another embodiment, the system has means for resetting to a maximum flush setting.

In a further embodiment, the system includes mounting means for mounting the system on an inside face of a front wall of a cistern.

Detailed description of the invention The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic front view showing a conventional WC cistern to illustrate the context of the invention; Fig. 2 is a diagrammatic side view showing part of a flush control system of the invention; Fig. 3 is a diagrammatic front elevation in the direction of the arrow A of Fig. 2; Fig. 4 is a diagrammatic cross-sectional elevational view in the direction of the arrow A of Fig. 2 showing a control valve in more detail; Fig. 5 is a plan view of the control valve showing an outer container with twin floats and needle valve; Fig. 6 is a front elevation of the outer container with an adjustment lever shown in mid-position; Fig. 7 is a plan view of the container shown in Fig. 6; Figs. 8 and 9 are plan and elevational views of a float bridge and a needle valve pipe; Fig. 10 shows front and side views of a support bracket; Fig. 11 shows side and front views of an automatic resetting lower receptacle.

Referring to the drawings, and initially to Fig. 1 there is shown a conventional WC cistern 1. The cistern 1 comprises a water tank 2 covered by a lid (not shown).

The cistern 1 also comprises a syphon 3 of the conventional U-shaped configuration having a rising leg housing a plunger 4 to cause the syphonic action. The plunger 4 is pulled upwardly by a lever 5 connected to a user handle. The water level is controlled by a float valve 6.

Referring to the remaining drawings, a flush control system 10 of the invention is shown. The flush control system 10 comprises a pair of support brackets 11 which extend upwardly over the top side edge of a front wall 8 of the cistern tank 2. As shown in Fig. 10, the support brackets 11 each have vertically spaced-apart apertures 12 so that the height of a control receptacle 20 of the system may be adjusted on the bracket 11. Each support bracket 11 has a retaining lip 13 at an upper end which allows it to grip at the top edge of the cistern water tank wall 8.

The flush control system 10 also comprises a control receptacle 20 above which there is a control lever 21 connected by a control line 22 which extends up over the cistern water tank wall 8 and terminates in a user control knob 23. The lever 21, the line 22 and the knob 23 form a user control means. The lever 21 is also connected by a suspension line 24 to a lower receptacle 25, shown in more detail in Fig. 11. The latter is used for providing an automatic default to a reduced flush setting and for setting the level of maximum flush. The system 10 also comprises an air control means comprising a flexible pipe 26 which is connected at one end to the syphon 3 at the bend and at the other end to the control receptacle 20.

This is most clearly shown in Fig. 2. The pipe 26 is installed very simply by drilling horizontally in the domed cover of the syphon 3 and push-fitting the flexible pipe 26 into the hole. This is possible because the pipe is of a flexible and durable material which does not degrade from contact with water. In this embodiment, the pipe is of silicone rubber material. At the other end, the flexible pipe 26 push fits over a discharge pipe 33 (Fig. 4) on the control receptacle 20. The flexibility of the pipe 26 accommodates relative movement of the control system (10) and the syphon 3, further simplifying installation.

The control receptacle 20 comprises a twin float 31 and 32 and needle 36. The lever 21 presses down on a float bridge 34 making contact at point 41 (see Fig. 4). The remaining parts of the control receptacle 20 are best described in the following description of how it operates.

In operation, a flushing action is begun by operation of the external handle which lifts the plunger 4 in the syphon. The general water level in the cistern tank 2 rapidly recedes below the rim of the control receptacle 20, which is located about 20 mm below the full water level. The syphonic action generates a reduced pressure in the syphon which is transmitted through the pipe 26, and the pipe 33 to an inlet opening 45 at an inner end of the pipe 33 which forms with the needle 36 a water discharge valve 46 for the control receptacle 20. This reduced pressure causes water to flow from the control receptacle 20 at a rate which depends on the extent of opening of the discharge valve 46, which in turn depends on the relative position of the needle 36 and the pipe 33.

It must be borne in mind that the needle 36 moves relative to the pipe 33.

If the cistern is flushed when the needle 36 is in the bottom or full open position as illustrated in fig. 4, water is quickly removed from the control receptacle 20 by the pipes 26 and 33. When the water level in the control receptacle 20 drops to the level of the bottom of the pipe 33, air will be drawn into the syphon 3, thus breaking the syphonic action and stopping the flush. Thus, the duration of the flush is dependant on the height of the needle 36, that is the position of the needle 36 relative to the pipe 33 or opening 45. The height of the needle is set by adjustment of the control knob 23 which operates the lever 21 through the line 22. A 5 mm movement of the knob 23 gives approximately 1 mm height adjustment of the needle 36. The total adjustment of the control knob 23 is about 50 nun and this approximately corresponds to flush volumes ranging from 3 litres to 13 litres. A simple adjustment of the height of the receptacle 20 on the support brackets 11 will increase or decrease the minimum flush volume.

In more detail, i.t will be appreciated that when the cistern tank 2 is re-filling with water after flushing, water will spill over the sides of the control receptacle 20 before completion of cistern refill. Because the twin floats 31, 32 are filled with a low density material 32a such as expanded polystyrene, a buoyancy force lifts the floats 31, 32 against the control lever 21. If the control lever 21 is at its lowermost position as shown in Fig. 4 the needle 36 will remain in the full open position. Thus, on subsequent flushing water will exit the control receptacle 20 very quickly and the syphonic action will be broken at an early stage.

If the control 21 lever is adjusted to the top position by pulling down on the control knob 23, the needle 36 will move up to the closed position. Thus, after flushing the control receptacle 20 will remain full of water and a normal full flush will occur as the lower opening 45 of the pipe 33 will never be exposed to air.

The lower receptacle 25 plays a very important part as it causes the system to default to a minimum flush by pulling the lever 21 downwardly after a full flush. This is because when the water level reaches the bottom of the cistern the buoyancy force will be removed from the lower receptacle 25 and a downward force equal to the weight of the container plus the weight of the water contained in it will be applied to the lever 21. This force will lower the floats 32 and needle 36 to a bottom or open position.

Thus, immediately after a full flush the system is re-set back to a reduced flush setting automatically. This is very important for water conservation.

By simply adjusting the length of line 24, i.e. to raise or lower receptacle 25, the level of maximum flush can be set to any desired level.

It will be appreciated that the invention provides a very effective solution to water conservation in operation of wC cisterns. There is automatic default setting back to a reduced flush after a full flush has been made. Also, the system may be easily converted to operate with automatic default setting back to maximum flush. This mode of operation can be obtained by simply removing lower receptacle 25, and using a slightly heavier control knob 23. Further, the system may be very easily installed. The control knob 23 operates in a very simple manner without any modification of the cistern water tank 2 being required. For example, when the lid of the cistern is replaced there is a small gap of about 2 mm between the top wall of the water tank 2 and the lid. This gap will not be evident because the lid will overhang the gap.

This gap allows a substantial weight to be pressed down on the support brackets 11 to ensure that the control system 10 is firmly fixed in position, while, at the same time allowing the user control line 22 to slide freely over the cistern wall for easy user control. Another important aspect is that if excessive tension is applied to the line, the lever 21 will swing to a top position in contact with the cistern lid, thus avoiding damage to the control receptacle. A further advantage is that the system has a long operating life as the forces of which are required to control it are extremely small. Indeed, it is estimated that the force required is less than 0.1 N.

A further advantage -is the simplicity with which both maximum flush level and minimum flush level can be adjusted.

The invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail.

Claims (12)

1. A flush control system for a WC cistern, the control system comprising a conduit connected to the syphon to allow inlet of air to break the syphonic action, air control means to control the timing of air inlet to the conduit, and a user control means.

2. A flush control system as claimed in claim 1, wherein the user control means comprises a control handle which is connected to the air control means by a ribbon or the like which extends over the cistern water tank wall and underneath the cistern lid.

3. A flush control system as claimed in claim 2, wherein the user control means is a handle or knob at the end of a ribbon which may be pulled to set the flush volume.

4. A flush control system as claimed .in any preceding claim, wherein the air control means comprises an adjustable flow restrictor.

5. A flush control system as claimed in claim 4 wherein the flow restrictor has means for timing access of air to the conduit in response to the flow rate of water from a control receptacle.

6. A flush control system as claimed in claim 4 or 5 wherein the adjustable flow restrictor comprises a needle valve, the settings of which are controlled by the user control means.

7. A flush control system as claimed in claim 6 wherein the settings are controlled by lifting or lowering a control lever connected to one part of the needle valve.

B. A flush control system as claimed in any preceding claim, wherein the system has means for resetting to a default reduced flush setting.

9. A flush control system as claimed in claim 9, wherein said resetting means comprises a water receptacle mounted at a lower level in the cistern and comprising means for pulling one part of an adjustable flow restrictor to an open position to allow water escape from the control receptacle for a reduced flush.

10. A flush control system as claimed in any preceding claim wherein the system has means for resetting to a maximum flush setting.

11. A flush control system as claimed in any preceding claim wherein the system includes mounting means for mounting the system on an inside face of a front wall of a cistern.

12. A flush control system for a WC cistern substantially as hereinbefore described with reference to the accompanying drawings.