WO2014035339A1

WO2014035339A1 - Sitting and squatting water closet with seat inner wall flushing

Info

Publication number: WO2014035339A1
Application number: PCT/SG2013/000368
Authority: WO
Inventors: Ee Pin CHERN
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-08-27
Filing date: 2013-08-26
Publication date: 2014-03-06
Anticipated expiration: 2015-02-27

Description

SITTING AND SQUATTING WATER CLOSET

WITH SEAT INNER WALL FLUSHING

Technical Field

This invention relates to water closets (WC), also known as toilet bowls. Background

The modern western WC requires the user to sit on it during use. However, in many othei societies, for example Asian countries, squatting while defecating or urinating is a commorj practice. Studies have shown that adopting the squatting posture during elimination of bodily wastes has health benefits. However, persons with disorders of the knees or the back, foi example in elderly persons, may be unable to adopt a squatting posture. For such persons, they are constrained to using the sitting-type western WC. Therefore, the ideal WC is one that car cater to both sitting and squatting. Inventions that satisfy both these demands are disclosed in US patent 4,012,797 and International Patent Publication No. WO2010/030242 Al. The state oi the art is represented by the "Anglo-Indian WC" commonly available in India and the "dunzuo liangyong matong" (dual-use sit-squat WC) which has recently begun to appear in China.

The abovementioned International Patent Publication describes the disadvantages of the prior art very comprehensively. It further discloses provision of a cistern under the pan and supplying flush water to the siphon jet through a simple valve so that effective flushing can be achieved without using excessive amounts of water. However, this arrangement appears to have backflow problem.

The aforementioned patent documents also disclose seats that have a substantial dimension in the vertical direction when they are lowered for sitting. This means that there is a possibility that waste matter or contaminated water may splatter on the inner walls of the seat. These fouling matter dirty the toilet seat and is considered unhygienic. .

Further, the aforementioned patent documents disclose that the method of use includes squatting facing either direction. In practice, when squatting facing the wall with the seat raised, the user's face will be in close proximity to the underside of the seat. This is an awkward situation and unlikely to be well accepted by users.

It is with these backgrounds that the present invention is conceived. Summary

Embodiments of the present invention seek to provide a WC that overcomes the imperfections of the prior art in combination sitting and squatting WCs. Embodiments of the invention seek to provide a WC that may:

1. be usable with either a sitting or a squatting posture;

2. employ suitable flushing technologies with proven backflow prevention characteristics;

3. provide flushing of the inner walls of the seat when flushing is activated with the seat lowered;

4. automatically shut off seat flushing when flushing is activated with the seat raised.

According to an aspect, there is provided a water closet comprising a WC pan, a toilet seat configured to rest on the WC pan, and at least one flush fluid opening on the toilet seat in fluid communication with a flush channel of the WC pan when the toilet seat rests on the rim of the WC pan.

The at least one flush fluid opening may be configured to receive flush fluid from the flush channel and spread a thin film of water for cleaning inner walls of the toilet seat. Advantageously, a seat flushing arrangement is provided in the above water closet such that during flushing, the toilet seat may be cleaned as well, thus maintaining the cleanliness and hygiene of the toilet seat.

The water closet may further comprise a first fluid connector portion fitted on the WC pan, and a second fluid connector portion fitted on the toilet seat, wherein the first fluid connector portion and the second fluid connector portion are configured to mate to form a fluid connection when the toilet seat rests on the rim of the WC pan.

The first fluid connector portion may comprise a valve configured to allow flush fluid to flow out of the valve into the second fluid connector portion and out of the flush fluid opening when the first fluid connector portion and the second fluid connector portion mate with each other, and not allow flush fluid to flow when the first fluid connector portion and the second fluid connector portion are not mated. Advantageously, by incorporation of the above fluid connection between the toilet seat and the WC pan allows automatic cleaning of the toilet seat when the toilet seat has been used and is in the lowered position, and prevent water from spraying out when the toilet seat is raised.

The valve of the first fluid connector portion may comprise a regulator capable of regulating the flow rate and/or amount of flush fluid flowing out of the valve. The second fluid connector portion may comprise an activation mechanism configured to activate the first fluid connector to allow flow of water only when the first fluid connector portion and the second fluid connector portion mate with each other. The activation mechanism is receivable by the regulator, the activation mechanism further being adjustable for controlling the regulator to regulate the flow rate and/or amount of flush fluid flowing out of the valve.

Advantageously, the regulator and activation mechanism provide a user-controlled means to adjust the flow rate and/or amount of flush fluid used for cleaning the toilet seat.

In an implementation, the regulator may be a depressible central pin and the activation mechanism may be a push-bolt.

The water closet may further comprise a seal configured to seal the fluid connection between the first fluid connector portion and the second fluid connector portion when the first fluid connector portion and the second fluid connector portion mate with each other. Advantageously, the seal may prevent any water leakage from the fluid connection between the first fluid connector portion and the second fluid connector portion.

In an implementation, the seal may be an elastomeric boot.

The at least one flush fluid opening on the toilet seat may comprise at least one nozzle.

The water closet may further comprise a hood at the front end of the WC pan and a foot rest on each side of the WC pan. The foot rest may be elevated with respect to a floor. These features allow a user to use the WC pan in a squatting position.

The toilet seat may be pivotally coupled to the WC pan. This allows ease of use of the water closet between sitting and squatting position, in which a user lowers the toilet seat when using the water closet in a sitting position and lifts up the toilet seat when using the water closet in a squatting position.

The toilet seat may be of a hollow shell construction. The toilet seat may comprise strengthening webs within the hollow shell of the toilet seat. The toilet seat may further comprise at least one water channel within the hollow shell of the toilet seat in fluid communication with the at least one flush fluid opening. The shell may comprise a seat surface for a user to sit upon, an inner wall extending from the seat surface and forming a passage suitable for the user to pass substance through the passage into the WC pan, and an outer wall extending from the seat surface. With a hollow shell construction, the toilet seat may conceal the strengthening webs and the components of the toilet seat flushing arrangements. Further, the continuous external surface of the shell also allows ease of cleaning.

The at least one flush fluid opening may be on the inner wall of the toilet seat. The water closet may further comprise a flush mechanism to supply flush fluid to the flush channel of the WC pan. The flush mechanism may comprise an exposed flush valve or a concealed flush valve. The flush mechanism may further comprise an accumulator below the WC pan upstream of the said exposed or concealed flush valve. As an alternative to the exposed or concealed flush valve, the flush mechanism may comprise a pressurized cistern. These flushing technologies may provide backflow prevention.

Description of the Drawings

The accompanying drawings which are incorporated into and constitute a part of the description of the invention illustrate multiple embodiments of the invention and serve to explain the principles of the invention. It is to be understood, however, that the drawings are designed for the purposes of illustration only, and not as a definition of the limits of the invention for which reference should be made to the claims.

Figure 1 is a perspective view of an embodiment of the WC in accordance with the present invention. It is of the free-standing pedestal style, fitted with an exposed flush valve and shown with the seat raised for use with a squatting posture.

Figure 2 is a perspective view of another embodiment of the WC. It is of the back-to-wall pedestal style, fitted with a concealed flush valve with the seat lowered for use with a sitting posture. The bathroom wall is shown partially cut-away.

Figure 3 is a perspective view of another embodiment of the WC showing a slim concealed pressurised cistern installed behind the wall against which the WC is installed.

Figure 4 is a perspective view of another embodiment of the WC showing a decoupled cistern or vitreous china tank installed at the corner of the two walls nearest to the WC. For clarity, the seat is not shown.

Figures 5 and 6 are views of another embodiment of the WC. It is of the free-standing pedestal style, fitted with an exposed flush valve and having a bladder accumulator below the pan and foot rests supplying water to the flush valve. It is to be understood that the back-to-wall style of the WC, fitted with either choice of flush valve can also have such a placement of bladder accumulator. Figure 5 shows the view generally from the front of the WC while figure 6 shows a partial section view from the side without the seat.

Figure 7 is a partial section view with a detailed view of the water supply system for seat flushing with the seat lowered.

Figure 8 is similar to figure 7 but with the seat slightly raised. Detailed Description

In an embodiment, to retain the characteristic of effective flushing without excessive water consumption and yet provide backflow prevention, suitable flushing technologies that may be used for an embodiment of a sit-squat toilet are: 1) pressurised cisterns, 2) flush valves (also known as Flushometers) and 3) pumped flushing. For the former two technologies, the devices must be installed at a suitable height above the sit-squat pan to meet air gap regulations for the prevention of backflow. For the latter, suitable backflow prevention features must be incorporated.

Regardless of which flushing technology is adopted, the following constraint may be considered. For embodiments of the sitting and squatting WC of the present invention, there is a skirt below the seat ring. This means that when the seat is raised, it may have to lean much further back compared to a conventional seat due to two reasons: 1) the centre of gravity of the seat is such that the raised balance point is at a more exaggerated leaned-back position, and, 2) sufficient clearance has to be provided for the user's back when squatting above the pan. This means that the pivot axis of the seat may have to be further forward of the leaning surface when raised (such as the back wall of the bathroom) compared to a conventional toilet seat. Furthermore, a sitting and squatting pan may be longer than a sitting pan. Thus the total measurement comprising the distance from back wall to the pivot axis and the length of the pan may determine the overall length of embodiments of a sitting and squatting WC. In order to keep the overall length of such a WC compatible with the available space in a typical bathroom or toilet cubicle, any flushing technology that is employed must not further lengthen the WC to the point that it cannot be installed in the majority bathrooms or toilets.

For pressurised cistern technology, to keep within the aforementioned constraint, two design options may be available: 1) use a slim pressurised cistern that can be fitted behind a false wall against which the WC is installed, and, 2) use a pressurised cistern that is designed to be installed offset from the centre line of the WC, for example at the corner of the two bathroom walls nearest to the WC. The cistern can be designed to be used as it is or fitted inside a vitreous china tank. For the case where it is designed to be used as it is, the most likely style is to be decoupled from the WC pan, with a flush pipe between the cistern and the WC pan. For the case where it is designed for fitting inside a tank, the latter can be either decoupled, close-coupled or unitary with the WC pan. In either case, the decoupled style permits the WC to be designed as either freestanding pedestal or back-to-wall style. Currently, the shape of commercially available pressurised cisterns may not be suitable for these two options. Customisation may be necessary. For flush valve technology, two design options may also be available: 1) exposed, and, 2) concealed. In exposed designs, the flush valve may be installed slightly offset from the centreline of the WC so that it does not affect the leaning of the raised seat. This design option also permits the WC to be designed as either freestanding pedestal or back-to-wall style. In concealed designs, the flush valve may be completely flat with the wall and does not contribute to the overall length of the toilet at all, nor does it impede the inclined leaning of the toilet seat when raised. Both manually actuated and automatic sensor actuated flush valves may be used. However, an important consideration when using flush valve technology is the characteristic of the water supply. In some restrooms, the water supply system is designed specifically to allow the use of flush valves, i.e., the flowing pressure at the required flow rate meets or exceeds the minimum required operating pressure of the flush valve. However, in many restrooms in older buildings and most residential bathrooms, the water supply is not intended to supply flush valves. Installation of a flush valve must then be complemented with a bladder accumulator immediately upstream. In an embodiment, a convenient location for the installation of this accumulator is under the pan and/or foot rests. It must be emphasised that the fundamental purpose of such an accumulator is different from the cistern described in the aforementioned International Patent Publication. In the prior art, the cistern forms part of the WC and supplies water into the pan through a simple valve without any means of backflow prevention. In this embodiment, the accumulator forms part of the water supply and supplies water to a flush valve whose design and method of installation incorporates all the mandatory backflow prevention measures.

For pumped flushing technology, water is supplied via a regular fill valve with suitable backflow prevention devices to fill a holding tank. When flushing is activated, the pump draws water from this tank and forces it at high pressure into one or more water inlets of the WC. In an embodiment, the necessary components of this technology may also be concealed under the pan and/or foot rests. Obviously it does not alter the external appearance of the WC, does not affect its overall length and does not impede the inclined leaning of the seat when raised. Use of this technology may also permit the WC to be designed as either freestanding pedestal or back-to- wall style.

The toilet seat in embodiments of the present invention is of hollow shell construction. The difference from the aforementioned International Patent Publication is that the inner vertical walls are slightly smaller than the opening of the WC pan so that any substance dribbling down the walls will ultimately fall into the pan. Due to the hollow shell construction, the contour of the outer vertical walls can be designed to be an extension of the outer surface of the pan, thus giving a unified appearance of pan and seat. Hollow shell construction also means that strengthening webs can be concealed inside the shell, which makes the seat less prone to dirt accumulation and easier to clean. An additional advantage is that toilet seat flushing and cleaning arrangements may be incorporated in the hollow shell, in which components such as the water channels of the seat flushing arrangements may be concealed within the hollow shell.

In a further embodiment, to achieve automatic turn-on of seat flushing when the seat is lowered and automatic turn-off of the seat flushing when the toilet seat is raised, a novel coupling may be provided between a point above the flush channel in the WC pan and the oppositely-facing location on the lower surface of the toilet seat. The two sub-parts of the coupling are separated when the toilet seat is raised and coupled when the toilet seat is lowered. The first sub-part which is attached to the WC pan has a valve that prevents the escape of water when it is in the separated state. When the other sub-part which is attached to the seat is lowered onto the first sub-part, the valve is triggered open by the former, allowing water to flow through both sub-parts. Suitable sealing may be provided to prevent water leakage from the joint between the two sub-parts, for example with an elastomeric boot. Suitable means of adjusting the flow rate may also be provided, for example with an adjustable-length push-rod that triggers the valve.

Referring to figure 1, the first embodiment of the present invention includes an elongated WC pan 10 similar in ratio of length to width to an eastern squatting-type WC pan. Additionally, there is a hood 11 at the front end of the WC pan 10 to contain urine spray. Along each side of the WC pan 10 is a foot rest 12. The rim 13 of the WC pan 10 is of sufficient height above the foot rests 12 such that when a user squats on them, the rim 13 prevents the feet from slipping into the WC pan 10. At the same time, the height of rim 13 is not too high so that it does not come into contact with the user's buttocks. The foot rests 12 and WC pan 10 are supported by the pedestal 14 at a suitable height for easy mounting of the foot rests 12. The pedestal 14 is of the free-standing design, i.e., not closely fitting with the back wall. The back-to-wall pedestal design which shall be described later, can also be used in this embodiment. The toilet seat 15 is shown in the raised position, allowing the WC to be used with a squatting posture. Among the many pressurised flushing systems that can be employed, figure 1 shows the exposed flush valve 16 being used. Upon activation, the flush fluid (e.g. water) flows via flush pipe 17 into a top inlet 18 of the WC, whose internal channels divert water to the underside of rim 13 and the siphon jet inlet (not visible in figure 1). At a suitable location on the rim 13, is a seat flushing valve 19, which is closed when the seat 15 is raised as shown.

Figure 2 shows the second embodiment of the present invention. The first difference between this and the first embodiment is that this embodiment has a back-to-wall pedestal 20. As previously described, this back-to-wall pedestal design can also be used in the first embodiment. The second difference is that this embodiment uses a concealed flush valve 21 with a concealed flush pipe 22 that carries flush fluid into a back inlet 23. Figure 2 also shows the toilet seat 15 in the lowered position, allowing the WC to be used with a sitting posture. With the toilet seat 15 lowered as shown, flushing of the inner walls 24 of the seat is enabled. Flush fluid for seat flushing flows out from nozzle 25. Details of the seat flushing arrangement will be described later.

Figure 3 shows the third embodiment of the present invention. It is nearly identical to the second embodiment except that a slim pressurised cistern 26 is used.

Figure 4 shows the fourth embodiment of the present invention. A decoupled pressurised cistern 27 is used. In order not to obstruct the raised seat, the cistern 27 is offset to one side. As an exposed flush pipe 17 is used, flush fluid enters the WC via the top inlet 18. This means that the free-standing pedestal 14 can be used in this embodiment. Notwithstanding this, the back-to- wall pedestal can also be used with this embodiment. Visually identical to this embodiment is the one where the cistern is replaced by a vitreous china tank with a pressurised cistern (which may be made of other materials such as plastic) installed inside.

Figures 5 and 6 show the fifth embodiment of the present invention. This embodiment is suitable for installation in a bathroom whose water supply system is not intended to supply a flush valve. The flushing system uses an exposed flush valve 16. However, a concealed flush valve can also be used in this embodiment. Referring to figure 5, for the case where an exposed flush valve is used, the flush valve 16 is installed in an offset manner so that it does not obstruct the raised seat 15. For a pleasing and balanced appearance, the stop valve 28 of the flush valve may be installed offset on the opposite side. Referring to figure 6, the stop valve 28 receives its water supply from bladder accumulator 29 via a large supply pipe 30. The accumulator 29 is located in the space below the pan and/or foot rests. A small stop valve 31 provides water to accumulator 29.

Figures 7 and 8 serve to illustrate the seat flushing arrangement which is applicable to any embodiment of the present invention. As shown in Figure 7, a WC according to an embodiment includes a WC pan 10, a toilet seat 15 configured to rest on the WC pan 10, and at least one flush fluid opening 25 on the toilet seat 15 in fluid communication with a flush channel (not shown) of the WC pan 10 when the toilet seat 15 rests on the rim 13 of the WC pan 10. Referring to figure 7, when the seat 15 is lowered and flushing occurs, the at least one flush fluid opening 25 may receive flush fluid (e.g. water) from the flush channel and spread a thin film of water across the inner wall 24 of the toilet seat 15 for cleaning the inner wall 24 of the toilet seat 15. The at least one flush fluid opening 25 may comprise at least one nozzle. Referring to Detail A of figure 7, in an embodiment, the WC further includes a first fluid connector portion 19 fitted on the WC pan 10 and a second fluid connector portion 37 fitted on the toilet seat 15. The first fluid connector portion 19 may be disposed at a location on the WC pan 10 in which the first fluid connector portion 19 is in fluid communication with the flush channel of the WC pan 10 such that flush fluid may be channelled to the first fluid connector portion 19. The second fluid connector portion 37 may be disposed at a location on the lower surface of the toilet seat 15 and positioned directly opposite the first fluid connector 19. In this way, the first fluid connector 19 and the second fluid connector 37 can mate to form a fluid connection when the toilet seat 15 is lowered and rests on the rim 13 of the WC pan 10 as shown in Figure 7.

The second fluid connector 37 may be in fluid communication with the flush fluid opening 25 via a water channel 32 in the hollow shell forming the toilet seat 15.

Referring to Detail B of figure 8, the first fluid connector portion 19 may include a valve 38. Referring to figure 7, when the first fluid connector portion 19 and the second fluid connector 37 mate to form a fluid connection, the valve 38 may allow flush fluid flowing inside the flush channel of the rim 13 of the WC pan 10 to flow out from the first fluid connector portion 19 via the valve 38 and flow through the second fluid connector 37 to the flush fluid opening 25. The flush fluid opening 25 then spreads a thin film of water that cleans a major portion of the inner wall 24 of the toilet seat 15.

Referring to figure 8, when the toilet seat 15 is raised and is not resting on the rim 13 of the

WC pan 10, the first fluid connector portion 19 and the second fluid connector portion 37 are no longer mated. When the first fluid connector portion 19 and the second fluid connector portion 37 are not mated, the valve 38 does not allow flush fluid to flow out of the first fluid connector portion 19.

Referring to Detail B of figure 8, the valve 38 of the first fluid connector portion 19 includes a regulator 36 which may regulate the flow rate and/or the amount of flush fluid flowing out of the fluid connector portion 19 via the valve 38.

Referring to Detail A of figure 7, the second fluid connector portion 37 includes an activation mechanism 33 which may activate the first fluid connector 19 to allow flow of water only when the first fluid connector portion 19 and the second fluid connector portion 37 mate with each other. The activation mechanism 33 may be receivable by the regulator 36. The activation mechanism 33 may also be adjustable such that adjusting the activation mechanism 33 allows a user to control the flow rate and the amount of water that the regulator 36 regulates to flow out of the valve 38. The second fluid connector portion 37 may further include a seal 34 for sealing the fluid connection between the first fluid connector portion 19 and the second fluid connector portion 37 when the first fluid connector portion 19 and the second fluid connector portion 37 mate with each other.

In an implementation, the regulator 36 may be a depressible central pin and the activation mechanism 33 may be a push-bolt. The seal 34 may be an elastomeric boot. When the toilet seat 15 is lowered, push-bolt 33 depresses the central pin 36 of the valve of the first fluid connector portion 19 to allow water to flow out. Elastomeric boot 34 seals the exit of the first fluid connector portion 19 and thus water can only flow along its intended path, through the second fluid connector portion 37 to water channel 32, which may be in the form of a tube. The amount of depression of the central pin 36 can be adjusted by screwing the push-bolt 33. Push-bolt 33 is provided with a screwdriver slot at its upper tip so that adjustment can be performed with the seat lowered and while observing whether there is appropriate coverage by the water film. Once the desired coverage is obtained, push-bolt 33 is locked into position using set screw 35.

Referring to figure 8 and its Detail B, with the toilet seat 15 raised, central pin 36 of the valve of the first fluid connector portion 19 is not depressed. Hence water does not flow out of the first fluid connector portion 19.

Various modifications and variations to the seat flushing arrangement as shown in Figure 7 and Figure 8 may be apparent to a person skilled in the art. It is understood that variations in the components of the seat flushing arrangement may be possible and the figures are provided by way of an example only.

Thus it can be seen that a water closet has been provided which eliminates the problems associated with back flow and/or dirty toilet seat. Such water closet in accordance with the various embodiments disclosed can provide backflow prevention and toilet seat flushing means.

While only five embodiments of the present invention has been described and illustrated, it is to be understood that many changes, modifications and variations could be made to the water closet of the present invention without departing from the scope or spirit of the invention.

Claims

1. A water closet comprising:

a WC pan;

a toilet seat configured to rest on the WC pan; and

at least one flush fluid opening on the toilet seat in fluid communication with a flush channel of the WC pan when the toilet seat rests on the rim of the WC pan.

2. The water closet as claimed in claim 1, wherein the at least one flush fluid opening is configured to receive flush fluid from the flush channel and spread a thin film of water for cleaning inner walls of the toilet seat.

3. The water closet as claimed in claim 1 or 2, further comprising:

a first fluid connector portion fitted on the WC pan, and a second fluid connector portion fitted on the toilet seat,

wherein the first fluid connector portion and the second fluid connector portion are configured to mate to form a fluid connection when the toilet seat rests on the rim of the WC pan.

4. The water closet as claimed in claim 3, wherein the first fluid connector portion comprises a valve configured to allow flush fluid to flow out of the valve into the second fluid connector portion and out of the flush fluid opening when the first fluid connector portion and the second fluid connector portion mate with each other, and not allow flush fluid to flow when the first fluid connector portion and the second fluid connector portion are not mated.

5. The water closet as claimed in claim 4, wherein the valve comprises a regulator capable of regulating the flow rate and/or amount of flush fluid flowing out of the valve.

6. The water closet as claimed in any of claims 3-5, wherein the second fluid connector portion comprises:

an activation mechanism configured to activate the first fluid connector to allow flow of water only when the first fluid connector portion and the second fluid connector portion mate with each other.

7. The water closet as claimed in claim 6, wherein the activation mechanism is receivable by the regulator, the activation mechanism further being adjustable for controlling the regulator to regulate the flow rate and/or amount of flush fluid flowing out of the valve

8. The water closet as claimed in claim 7, wherein the regulator is a depressible central pin and the activation mechanism is a push-bolt.

9. The water closet as claimed in any of claims 3-8, further comprising a seal configured to seal the fluid connection between the first fluid connector portion and the second fluid connector portion when the first fluid connector portion and the second fluid connector portion mate with each other.

10. The water closet as claimed in claim 9, wherein the seal is an elastomeric boot.

11. The water closet as claimed in any of the preceding claims, wherein the at least one flush fluid opening comprises at least one nozzle.

12. The water closet as claimed in any of the preceding claims further comprising:

a hood at the front end of the WC pan; and

a foot rest on each side of the WC pan.

13. The water closet as claimed in claim 12, wherein the foot rest is elevated with respect to a floor.

14. The water closet as claimed in claim any of the preceding claims, wherein the toilet seat is pivotally coupled to the WC pan.

15. The water closet as claimed in any of the preceding claims, wherein the toilet seat is of a hollow shell construction.

16. The water closet as claimed in claim 15, wherein the toilet seat comprises strengthening web within the hollow shell of the toilet seat.

17. The water closet as claimed in claim 15 or 16, wherein the toilet seat further comprises at least one water channel within the hollow shell of the toilet seat in fluid communication with the at least one flush fluid opening.

18. The water closet as claimed in any of claims 16-18, wherein the shell comprises:

a seat surface for a user to sit upon;

an inner wall extending from the seat surface and forming a passage suitable for the user to pass substance through the passage into the WC pan; and

an outer wall extending from the seat surface.

19. The water closet as claimed in claim 18, wherein the at least one flush fluid opening is on the inner wall of the toilet seat.

20. The water closet as claimed in any of the preceding claims, further comprising a flush mechanism to supply flush fluid to the flush channel of the WC pan.

21. The water closet as claimed in claim 20, wherein the flush mechanism comprises an exposed flush valve.

22. The water closet as claimed in claim 20, wherein the flush mechanism comprises a concealed flush valve.

23. The water closet as claimed in any of claims 21 or 22, wherein the flush mechanism further comprises an accumulator below the WC pan upstream of the said exposed or concealed flush valve.

24. The water closet as claimed in claim 20, wherein the flush mechanism comprises a pressurized cistern.