The present invention relates to a cistern and in particular to a cistern suitable for installation in confined areas.

Background of the Invention

Concealed cisterns are a common feature in many bathrooms. A concealed cistern is a cistern that is hidden from view by locating the cistern inside a box, bathroom cabinet or behind a bathroom wall. The cistern is connected to a water supply and feeds a style of toilet pan known as a "back to the wall" pan. The back to the wall pan has a flat rear portion for abutting directly to the bathroom wall, box or cabinet.

Commonly, cistern boxes are constructed from plastic and are cuboid in shape. As an example, a cistern may be 330mm wide by 200mm high by 150mm deep and arranged to comfortably hold around six litres of water. A circular valve is provided in the cistern base. This is sized relative to the cistern box to allow a flow that meets minimum flushing requirements.

Because of the dimensions of conventional cisterns, concealing them typically requires a specially designed unit that integrates the cistern into bathroom furniture or construction of a partition wall in order to conceal the cistern behind it.

Summary of the Invention

According to a first aspect of the present invention, there is provided a cistern comprising a tank connected to an outlet via an outlet valve, the outlet valve comprising at least one elongate flap.

By providing an outlet valve comprising an elongate flap, the flow of water that is releasable by the cistern may be increased relative to the flow achieved by traditional circular valves of the same width, in order to meet minimum flushing requirements whilst allowing a narrow cistern profile suitable for installing behind partition walls.

The elongate flap may be rectangular. By having a rectangular flap, the flow of water through the outlet valve during a flush can be maximized, whilst at the same time, permitting a narrow profile cistern for installing behind partition walls. The cistern may be divided into at least two chambers. The chambers may be formed by at least one divider located within the cistern. The cistern may have a plurality of elongate flaps. Each chamber may be provided with at least one elongate flap.

The cistern may be provided with an inlet for providing flushing liquid. The provision of flushing fluid by the inlet to the tank may be controllable by at least one inlet valve. The inlet valve may comprise at least one float. The float may be arranged to be buoyantly supportable by fluid in the cistern. The float valve may be operable responsive to the level of flushing fluid in the cistern. The inlet valve may be arranged to divide a supply of flushing fluid into two or more supplies of flushing fluid.

The cistern may be provided with a plurality of inlet valves and/or floats and/or float valves. Each chamber may be provided with at least one float and/or float valve, individually operable responsive to the level of flushing fluid in the respective chamber. The provision of flushing fluid to each chamber may be individually controllable by the float and/or float valve associated with that chamber.

The cistern may have a maximum thickness of 40mm or less. The cistern may have a minimum height of at least 300mm, and preferably 650mm or less. The cistern may have a maximum width of 400mm or less, and preferably 380mm or less. In this way, the cistern may be small enough to fit between commonly used joists in a partition wall. The divider may extend at least 200mm in height from a base of the cistern.

The tank may be shaped as a cuboid. The tank may be connected to the outlet via a funnel. The outlet valve may be provided between the funnel and the tank.

The funnel may be affixed to or integral with the tank. The funnel may comprise an inlet for receiving flushing fluid from the tank and an outlet for providing flushing fluid to a toilet pan. The funnel inlet may be quadrilateral and/or elongate in cross section.

The funnel inlet may be rectangular. The funnel outlet may be circular in cross section. In this way, the cistern may utilise outlet valves having elongate and/or flap that is shaped as a quadrilateral but still connect to standard round pipe fittings with minimum loss of flushing force. The cistern may be formed in at least two parts. The funnel may be insertable into the tank. The funnel may comprise a perimeter wall. The perimeter wall may be arranged to engage at least one wall of the tank. The perimeter wall may be arranged to form a seal with at least one wall of the tank. The perimeter wall and/or tank may comprise at least one securing means for securing the funnel to the tank.

The securing means may comprise at least one engaging means and/or recess, arranged to engage with at least one complimentary recess and/or engaging means. The cistern may comprise a seal for sealing the funnel and the tank together, which may comprise an elastomeric seal.

The outlet may comprise a vertical pipe of, for example, a maximum 40mm. The outlet may comprise a horizontal pipe. The horizontal pipe may be arranged to couple with a toilet pan. The horizontal pipe may extend from the funnel or tank and be arranged to couple with the toilet pan. The horizontal pipe may be 44mm in diameter or more.

The elongate flaps may be provided with biasing means, in order to bias them into a closed position. The biasing means may be a spring. The flaps may be arranged to open downwardly into the funnel.

The elongate flaps may be selectively fastened by at least one fastening means. The fastening means may be operable to selectively hold the at least one flap in a closed position. The elongate flaps may be arranged such that, upon release of the fastening means, the corresponding elongate flap is openable against the biasing means by a weight of flushing fluid in the tank and/or chamber above a threshold weight in order to release flushing fluid from the tank and/or chamber.

The biasing means may be such that when the weight of flushing fluid in the tank and/or chamber is below a threshold, then the biasing means is arranged to close the at least one flap. The fastening means may comprise a biased fastening means, such that closure of the flap is operable to re-engage the fastening means to selectively hold the flap in the closed position.

The elongate flaps may be biased into a closed position by the weight of the flaps and/or flushing liquid in the tank. The flaps may be pivotably mounted. The flaps may be raised into the tank, in order to open the outlet valve. The elongate flaps may be operable responsive to at least one operating means, such as a flush button, lever, cord, handle or chain, and preferably the elongate flaps are operable responsive to at least two operating means or an operating means arranged to select one of at least two flush amounts. The operating means may be connected to the elongate flaps and/or a catch for holding the elongate flaps via a flush cable.

At least one operating means may be arranged to select a reduced flush. At least one operating means may be arranged to operate fewer outlet valves than at least one other operating means. The reduced flush operating means may be operable to release flushing liquid from one chamber.

The at least one other operating means may be operable to release flushing fluid from two or more chambers. The reduced flush operating means may be arranged to select supply of substantially two or three litres of flushing fluid to the outlet. The at least one other operating means may be arranged to select supply of substantially four or six litres of flushing fluid to the outlet.

Optionally, the second (full) flush must contain at least 1.5 litres of water more to add to the first volume.

The one or more operating means may be arranged to operate one or more fastening means.

The cistern may be provided with a service hatch. The service hatch may be located on a substantially vertical surface of the cistern. The hatch may be arranged on a surface of the cistern arranged to face the toilet pan. In this way, easy access to the cistern for maintenance may be provided.

In concealed cisterns, access from the top of the cistern is often difficult, as the top of the cistern is oriented away from the concealing wall. However, a front facing hatch allows easier access through a corresponding access in the concealing wall if required.

The service hatch may be recessed and/or flush with a surface of the cistern. In this way, the thickness of the cistern may be maximised whilst still allowing the cistern to fit behind a partition wall. The service hatch may be located above the divider and/or be proximate to the inlet valve.

According to a second aspect of the present invention is a toilet system comprising a cistern of the first aspect and a toilet pan. The toilet pan may be a "back to the wall" pan. The cistern may be coupled with the toilet pan by a horizontally extending pipe.

According to a third aspect of the present invention, there is provided a cistern comprising a tank connected to an outlet via an outlet valve, the outlet valve comprising at least one quadrilateral flap. The tank may be arranged to selectively hold a flushing liquid, which may comprise water. The flap may be a rectangular flap. The flap may be an elongate flap.

According to a fourth aspect of the present invention, there is provided a cistern that has at least two chambers arranged to selectively hold a flushing liquid, each of the chambers being provided with an outlet valve connected to an outlet.

The chambers may be defined by dividing a single tank into multiple separate chambers. The chambers may be defined by multiple separate modules or cartridges. Ideally, the separate tank modules or cartridges are individually removable from the cistern.

The cistern may be operable using at least one operating means, which may comprise a flush button, handle, cord or chain. The operating means may be operable to selectively open one or more of the outlet valves. In this way, the volume of flushing fluid released may be controlled.

According to a fifth aspect of the present invention is a cistern, the cistern being provided with a service hatch on a sidewall of the cistern. The cistern may comprise an inlet valve and/or an outlet valve. The service hatch may be arranged to allow access to the inlet and/or outlet valves. The service hatch may be recessed into the cistern. The service hatch may be arranged to be flush with an outer surface of the cistern. The cistern may be arranged to connect to a toilet pan. The hatch may be provided on a surface of the cistern facing the toilet pan.

According to a sixth aspect of the present invention, there is provided a method of assembling a cistern comprising providing a tank and a funnel and engaging the tank with the funnel. The cistern may be a cistern of the first aspect. By providing the tank and funnel separately, maintenance can be simplified, as the parts can be removed and repaired independently.

Brief Description of the Drawings

Various aspects of the invention will now be described by way of example only and with reference to the accompanying drawings of which:

Figure 1 is a schematic of a cistern having two chambers;

Figure 2 is a sectional schematic view showing the trap door arrangement of the cistern of Figure 1 ;

Figure 3 is a top planar view inside the cistern of Figure 1 ;

Figure 4 is a planar view of the bottom of a tank of the cistern of Figure 1 ;

Figure 5 is a cross sectional schematic showing the operation of the trap doors of the cistern of Figure 1 ; Figure 6 is a schematic of a cistern;

Figure 7 is a top planar view inside the cistern of Figure 6;

Figure 8 is a planar view of the bottom of a tank of the cistern of Figure 6;

Figure 9a is a schematic of a funnel for use with the cisterns of Figure 1 or Figure 6; Figure 9b is a schematic showing the connection of the cisterns of Figures 1 or 6 to a toilet pan;

Figure 10a is a schematic of a funnel for use in the cisterns of Figure 1 or Figure 6;

Figure 10b is a schematic showing connection of the cisterns of Figures 1 or 6 to a toilet pan;

Figure 11 shows a mounting arrangement for the cisterns of Figure 1 or Figure 6 for use with a partition wall;

Figure 12 is a plan view of the mounting arrangement of Figure 11 ;

Figures 13a and 13b are views of first and second pieces for assembly to form part of the cistern of Figure 1 ;

Figures 14a and 14b are views of first and second pieces for assembly to form part of the cistern of Figure 6;

Figure 15 is a schematic diagram of another cistern;

Figure 16(a) is a front view of a toilet in which the cistern of Figure 15 is fitted; Figure 16(b) is a side view of a toilet in which the cistern of Figure 15 is fitted;

Figure 17 is a perspective view of a lid of the cistern of Figure 15;

Figure 18 is a perspective view of two cartridges of the cistern of Figure 15; Figure 19 is a perspective view of an outlet of the cistern of Figure 15; Figure 20 is a perspective view of another outlet that could be used in the cistern of Figure 15, in place of the outlet of Figure 19;

Figure 21 (a) is a perspective view of a cistern that has a parabolic shaped front face, and

Figure 21 (b) is a side view of the cistern of Figure 21 (a).

Specific Description of the Drawings

Figures 1 to 5 show a cistern 5 that has a tank 10 divided into first 15 and second 20 chambers by a centrally located, integrally moulded divider 25. The tank 10 is connected via a funnel 30 to a flush pipe 35. The first 15 and second 20 chambers of the tank 10 are provided with respective first 40 and second 45 outlets. The outlets 40, 45 are connected via respective first 50 and second 55 flush valves to the funnel 30.

The divider 25 extends from a base wall 60 of the tank 10 and up two opposed sidewalls 65, 70 of the tank 10 to divide a lower portion 75 of the tank 10 into first 15 and second 20 isolated chambers. In each chamber is an overflow channel, in this case an overflow pipe 77, 79 that is open at an upper end so that fluid can flow into it when an overflow level has been exceeded. At its other lower end, each overflow pipe 77, 79 opens external to the chamber, so that water can flow out in the event of overflow.

The tank 10 is provided with a double-sided inlet valve 80 above the divider 25 for connection to a water main 85. The double side inlet valve 80 comprises an inlet 90 for connecting to the mains 85, which is divided into first 95 and second 100 filler channels. The filler channels 95, 100 are routed via first 105 and second 110 float valves to the first 15 and second 20 chambers respectively.

Each float valve 105, 110 has a float 115, 120 supported on a float arm 125, 130. Each float 115, 120 is arranged to be located in the respective chamber 15, 20 and be buoyantly supported by water 135 in the chamber 15, 20 such that the float 115, 120 may rise or fall depending on the level of water 135 in the chamber 15, 20. The rising and falling of the float 115, 120 is arranged to actuate the float arm 125, 130 and thereby selectively close or open the float valve 105, 110, in order to control the flow of water from the inlet 90 to the respective chambers 15, 20. If the level of water 135 in a chamber 15, 20 is below a threshold value, then the float valve 105, 110 for that chamber 15, 20 is opened, and the chamber 15, 20 is filled with water from the inlet 90. If the level of water 135 in a chamber 15, 20 is above a threshold value, then the float valve 105, 110 for that chamber 15, 20 is closed so no water is provided to the chamber 105, 110 from the inlet 90.

Each flush valve 50, 55 comprises a rectangular trap door flap 140, 145 pivotably mounted such that, in a closed position, the trap door flap 140, 145 seals the corresponding rectangular shaped outlet 40, 45 in the bottom 60 of each chamber 15, 20 of the tank 10. The trap door flaps 140, 145 are biased into the closed position by springs 150, 155. The trap door flaps 140, 145 are arranged to open by pivotably swinging down from the bottom 60 of the tank 10, against the force applied by the biasing spring 150, 155, and into the funnel 30 located below the tank 10.

Each flush valve 50, 55 is further provided with a catch 160, 165, arranged to selectively hold the trap door flap 140, 145 in a closed position. The catches 160, 165 are releasable under the control of a two part flush button 170. The two part flush button 170 has two sections 175, 180 that operate as a partial flush button 175 and a full flush button 180 respectively. The partial flush button 170 is connected to the catches 160, 165 via one or more flush cables 185 arranged such that operation of the reduced flush button 175 releases only one catch 160, i.e. the water 135 in only one chamber 15 is released, whereas operation of the full flush button 180 releases both catches 160, 165, i.e. the water 135 in both chambers 15, 20 is released. The tank 10 may be provided with multiple holes 190 to allow a choice of routing paths for the flush cable 185.

Operation of the flush button 170 to release a catch 160, 165 retracts the catch 160, 165, permitting the corresponding trap-door flap 140, 145 to be opened. If the force applied to the trap door flap 140, 145 by a weight of water 135 in the appropriate chamber 15, 20 is greater than the biasing force applied by the biasing spring 150, 155, then the weight of water 135 in the appropriate chamber 10, 15 will cause the trap door flap 50, 55 to open, releasing the water 135 through the outlet 40, 45 of the chamber 15, 20 and into the flush pipe 35 via the funnel 30.

Once enough water has been released such that the force applied by the weight of water 135 is less than the biasing force applied by the spring 150, 155, then the biasing spring 150, 155 forces the trap door flap 140, 145 into a closed position. The catch 160, 165 is biased, such that, after the flush button 170 is released, then the catch 160, 165 returns to a position such that when the trap door flap 140, 145

⁾ closes, the catch 160, 165 re-engages the flap 140, 145 and holds the flap 140, 145 closed until the next time the flush process is performed.

In an alternative embodiment, as shown in Figures 6 to 8, the tank 10' of the cistern 5' defines a single chamber 15'. In this case, only a single inlet valve 80' comprising a single float valve 105' is provided. In addition, only one outlet 40' and one outlet valve 50', controlling fluid communication between the tank 10' and the funnel 30 is provided.

The trap door flap 140' of the outlet valve 50' in this embodiment is arranged to open by pivotably rotating upwards into the tank 10' upon operation of the two part flush button 170. Operation of the partial flush button 175 is arranged to partially open the trap door flap 140', allowing less water 135 to escape, whilst operation of the full flush button 180 opens the trap door flap 140' by a greater amount than the partial flush button 175, allowing more water 135 to escape. Control of the closure of the flap 40' may be by any suitable means known in the art, such as providing the flap 40' with variable buoyancy in order to delay its closure.

Regardless of which of the above embodiments is used, the cistern 5, 5' may be provided with an access hatch 200 located on a front face 65 of the cistern 5, 5', facing toward a side at which a toilet pan 210 (as shown in Figures 9b and 10b) is to be located and preferably sited to allow access to the float valve 80, 80'. In the twin chamber tank 10, the hatch 200 is sited above the top of the divider 25. This allows easy access to the float valve 80 for maintenance when the cistern is concealed behind a wall, as a corresponding door may be built into the wall to allow access via the hatch 200 on the cistern 5, 5'. In contrast, it may be much more difficult to access a conventional top entry cistern, as the top of the cistern lies away from the wall.

In one example of a mounting arrangement for mounting any of the above cisterns 5, 5' to a toilet pan 210, as shown in Figures 9a and 9b, the funnel 30 of the cistern 5, 5' is arranged such that the flush pipe 35 extends substantially vertically out from the bottom of the funnel 30. This pipe 35 can be made of any length, and is generally of 37.5mm inside diameter. This allows the cistern 5, 5' to be mounted at a range of heights. The flush pipe 35 is then connected to a bend section for connecting to a back-to-the-wall toilet pan 210.

In another example of a mounting arrangement, as shown in Figures 10a and 10b, the flush pipe 35 may extend substantially horizontally from the lowest point of the funnel 30. This horizontally extending flush pipe 35 is directly connectable to the back-to-the-wall toilet pan 210. Mounting the cistern 5, 5' in this fashion may require less fitting work but may limit the height at which the cistern 5, 5' can be mounted.

This can be overcome by providing a flush pipe 35 having a greater diameter, for example, of 44mm inside diameter.

The cistern 5, 5' is sized to be 400mm wide or less and preferably 380mm wide or less. The cistern 5, 5' is also 40mm deep or less. When constructing stud partition walls, as shown in Figures 11 and 12, it is preferred to space the wooden wall support 215 posts 450mm apart. The preferred depth of wooden wall support posts 215 is 40mm deep. Therefore, the cistern 5, 5' may conveniently be snugly located behind a partition wall and between the wooden wall posts 215 so as not to protrude beyond the posts 215. The height of the cistern 5, 5' may then be selected in order to achieve storage of a specified volume of flush water 135. For example, the cistern 5, 5' may be at least 650mm high.

Where the preferred dimensions are used, the cistern 5, 5' may not work with standard fittings and/or the flow of flushing water 135 may be impaired. By having an elongated rectangular outlet 40, 50, 40' and outlet valve 50, 55, 50', the size of the outlet 40, 50, 40' is maximised, thereby allowing increased flow whilst maintaining the reduced cross sectional area of the cistern 5, 5'. By provision of a funnel, acting as a joining piece, the rectangular outlets may be joined to a conventional pipe having a reduced circular cross section, whilst maximising the force of the flush.

By making the cistern 5, 5' less than 380mm wide, a 20mm water inlet pipe 220 may be provided up one side of the cistern 5, 5', between the cistern 5, 5' and a wooden support post 215, whilst still allowing the cistern 5, 5' and pipe 220 to be located between two support posts 215 spaced 400mm apart.

For ease of manufacture, as shown in Figures 13a, 13b, 14a and 14b, the above cisterns 5, 5' are constructed in two sections 225, 230, the first section 225 defining the walls of the tank 10 (and in the case of the two chamber tank, the divider 25) and the second section 230 defining the funnel 30, the base 60 of the tank 10 and the outlet 40' or outlets 40, 50. The second section 230 is formed with a raised surface 235, having perimeter dimensions slightly smaller than those of the walls of the first section 225, such that the raised surface 235 of the second section 230 is snugly receivable inside the first section 225 to provide a water tight seal between the second section 230 and the first section 225. The raised surface 235 of the second section 230 is provided with engaging members 240 for engaging corresponding recesses 245 in the inside of the walls of the first section 225 so as to lock the two sections 225, 230 in place and allow quick assembly. Optionally, a rubber or soft plastic seal may be provided on at least part of the interface between the first 225 and second 230 sections in order to improve water tightness.

To improve the ability of the owner / installer to repair and maintain the cistern after installation, a modular cistern can be used in conjunction with the removable access panel. An example of a modular system 240 is illustrated in Figure 15. This has four basic parts or modules: a lid 245, which supports the inlet pipe work and valves, a middle tank section, which has two cartridges 250, 255, and an outlet part 260, which includes the funnel outlet, and acts as a base support for the two cartridges. This cistern is adapted to be used in conjunction with a wall mounted removable panel 265. As described previously, this has attached to it buttons and associated cabling for flushing. The front panel 265 is sized so that the each of the four modules of the cistern can be removed through it, thereby avoiding damage to the surrounding wall. In practice, the front panel would be approximately 25cm wide x 10cm high or less.

Figure 16(a) shows a view of the cistern 240 when fitted behind a removable panel 265, and Figure 16(b) shows a side view, with the cavity 270 formed between the main wall 275 and the stud wall 280 exposed. From these drawings, it can be seen that the cistern 240 is concealed behind the front panel 265 and wholly contained within the wall cavity, so that the only parts visible are the front panel 265 and the toilet pan 285. The cistern is also positioned and sized so that each of its parts can be removed in turn from the wall cavity through the hole covered by the front panel 265.

Figure 17 shows the lid 245 separately from the other parts. This provides a cover for the cartridges 250, 255 and houses a water inlet valve 285. The inlet 285 has a single water inlet pipe 290 that divides into two outlet pipes 295, 300, one for each cartridge 250, 255 of the cistern 240. There are two float valves, each having a float 305, 310 on the end of a rod and being weighted so it lies vertically in the tank. Each float is buoyantly supported by water in its cartridge such that the float rises or falls depending on the water level. The rising and falling of the float is arranged to selectively close or open the outlet pipes to control the flow of water to the respective cartridges 250, 255. When the water fills up inside one of the cartridges 250,255, its associated float 305, 310 rises and cuts off the water. At the upper end, each rod is hinged and offset so that when the lid 245 is taken off, the floats 305, 310 can be swung up inside the lid cover. This minimises the overall space taken up by the lid 245, so that it can be removed via the front panel hole.

Figure 18 shows the cartridges 250, 255 in more detail. The cartridges 250, 255 hold equal amounts of water, for example three litres of water, for the half or full flush. The cartridges 250, 255 are identical, which greatly simplifies manufacture and positioned in use as that they are complete mirror images of each other. Each cartridge 250, 255 has an internal wall defining a thin separate area 315, 320, which is open at the bottom to allow excess water to run down and out through the funnel into the pan 285 if the ball valve or water inlet valve in the lid 245 should fail. This is the overflow section.

Trap doors 325, 330 are pivotably fitted to the underside of each cartridge 250, 255, so that they can swing about a fixed point, down away from the bottom of the cartridges 250, 255. Each trap door 325, 330 is connected at its fixed end to a spring 335, 340 that runs from the top of the trap door face into the cartridge 250, 255 and is attached to the inside wall of the side of the cartridge 250, 255. This retracts the hinged door 325, 330 back to the horizontal position when all or most of the weight of the water has been flushed and the cartridge(s) 250, 255 is slowly refilling from the float valve. The door 325, 330 is held in the horizontal position using a clip 345 (only one shown). The top face of the trap door 325, 330 has a soft rubber or silicon seal that fits to the underside of the cartridge 250, 255 when in the clipped position to prevent water leaking out. The clip 345 is shaped so that when its associated trap door 325, 330 is being pulled from an open position back into its retracted position the spring forces the clip 345 underneath the trap door 325, 330 to hold it in position to improve the seal effect on the trap door 325, 330.

The trap doors 325, 330 are controlled using buttons on the front panel 265, which are connected via cables to the trap door clip 345. The cable 350 for each trap door extends through the overflow section 320 and out through a notch in the top of the cartridge 255 underneath the lid 245 and onto the buttons on the front panel. As before, one button on the front panel controls release of one trap door 325 and the other larger button controls release both trap doors 325, 330, so that a half flush and a full flush can be provided.

The cartridges of Figures 15 and 17 are designed so that all moving parts within the cartridge, for example the spring. This means that are protected. In practice, this is a significant advantage when removing the cartridge from the cavity, as it limits the scope for damage.

Figure 19 shows the bottom outlet section 260. This has a tray or support portion 355 from which extends a funnel section 360 that has a centrally positioned pipe outlet 365. The outlet section 260 has no parts, springs or mechanism inside. The tray or support portion 355 is shaped to receive the two cartridges 250, 255 snugly whilst allowing the trap doors 325, 330 enough space to swing open to allow water to flow into the funnel. Each cartridge 250, 255 is fitted inside the bottom outlet section in pre moulded sections either slid beside each other or with a separator in the middle, so that when the lid 245 is removed either section can be taken out through the front panel one at a time or reinstalled through the front panel individually after any repairs or replacement have been carried out in the bathroom.

Figure 20 shows another outlet section 340 that could be used in place of the symmetrical section of Figure 19. In this case, the funnel portion 345 is shaped to that the pipe outlet 350 is offset to one side, i.e. not centrally positioned. This type of outlet 340 allows the cistern 240 to be fitted inside the wall slightly to the left or the right of the pan. When the cover is removed, directly in front of the panel there is one of the cartridges 250, 255 and a side part of the lid. The lid and the visible cartridge can be removed, and then the other cartridge slid across into the front panel space and out of the cavity.

A skilled person will appreciate that variations of the disclosed arrangements are possible without departing from the invention. For example, although the cistern 5, 5' is described as being 650mm high by 380mfn wide by 40mm deep, a skilled person would appreciate that the actual dimensions of the cistern 5, 5' may vary, although preferably the depth is 40mm or less and the width is 400mm or less. Furthermore, whilst the embodiments described herein refer to mounting the cistern 5, 5' behind a partition wall, it will be appreciated that the cistern 5, 5' does not necessarily need to be mountable behind a partition wall and instead may be usable to provide an increased flush and/or low profile cistern.

In addition, although in certain embodiments, the flush pipe 35 is described as extending substantially horizontally or substantially vertically from the cistern, it will be appreciated that in practice, the flush pipe 35 may vary slightly from these configurations, for example, instead of being exactly horizontal, the flush pipe 35 may slope slightly away from the cistern 5, 5' and towards the pan 210, in order to ensure that water is drained from the flush pipe 35 after flush. Also, whilst the cistern and cartridges are shown generally as having flat outer surfaces, they could instead have a parabolic front, as illustrated in Figures 21 (a) and (b). This shape would allow the cartridges to be removed even if tiles and plasterboard were positioned against the front face of the cartridge. Accordingly the above description of the specific embodiment is made by way of example only and not for the purposes of limitation. It will be clear to the skilled person that minor modifications may be made without significant changes to the operation described.