WO2009066096A1

WO2009066096A1 - Water conserving toilet

Info

Publication number: WO2009066096A1
Application number: PCT/GB2008/051023
Authority: WO
Inventors: William Hugh Salvin Rampen
Original assignee: Straight Flush Limited
Priority date: 2007-11-20
Filing date: 2008-10-31
Publication date: 2009-05-28
Also published as: EP2231938A1; GB0722735D0; US20100287692A1; AU2008327733A1

Abstract

Disclosed is a toilet (1) comprising a toilet bowl (2), a passage which extends from the base of the toilet bowl to a drain outlet (30), and a gate (100), the gate having an open position which allows water within the toilet bowl to flow out of the drain outlet by way of the passage and a closed position in which the gate retains a continuous body of water (98) within the toilet bowl and a portion of the passage, up to a fill level (96), the toilet further comprising a divider (19) arranged to close off the passage above the fill level and to extend below the fill level at a location intermediate the toilet bowl and the water line (100) where the surface of the continuous body of water contacts the gate, to form a water trap in use when the gate is in the closed position and water is retained up to the fill level. The gate may be a flap operated by a hydraulic actuator (36), responsive to operation of a manually operable flush control, using mains water as the hydraulic fluid. Water is supplied by a spray ring around the rim of the toilet bowl. The toilet requires less water to flush than toilets including a conventional S-shaped water trap.

Description

Water Conserving Toilet

Field of the invention

The present invention relates to the field of water conserving toilets.

Background to the invention

At the present time, one third or more of the water consumed by many households is used to flush conventional toilets, which have a cistern and S-shaped water trap. In conventional toilets, only a small fraction of the flush water is required to cleanse the toilet bowl and the majority of the flush water is employed to provide hydraulic energy sufficient to impart kinetic energy to the water already present in the toilet bowl and to carry solids through the S-shaped water trap.

Many innovations have been proposed to control the amount of flush water dispensed by a cistern. However, the kinetic energy required to carry solids through an S-shaped water trap limits the extent to which it is possible to conserve water in this way. It is known to provide a toilet, such as a chemical toilet, in which the S- shaped water trap is dispensed with and an aperture with a simple flap is provided at the base of the toilet bowl to provide a passage for solids to be evacuated vertically downwards from the base of the bowl. This avoids the requirement for a high volume of flush water to be provided to force solids through an S-shaped water trap. However, unless the flap is gas tight, gas will leak from the drain outlet to the surrounding atmosphere. It is difficult to provide a reliable gas tight seal around a moveable flap, particularly as the flap may be soiled in use, and particularly where it is desirable to retain a body of water within the toilet bowl prior to flushing. Furthermore, a toilet of this type could not be fitted into the toilet fixture which is currently typical in the UK, in which the drain outlet mates with a pipe, the interior base of which is below the base of the toilet bowl, extending backwards from the toilet, above floor level.

The present invention aims to provide an improved water conserving toilet, which requires less water to flush than conventional toilets and which resists the passage of gas from the drain outlet to the surrounding atmosphere. Some embodiments of the invention employ a cost-effective automatic flush mechanism which does not require an electricity supply. Some embodiments of the invention provide a water conserving toilet which can be fitted to toilet fitments in which the drain outlet mates with a pipe, the interior base of which is below the base of the toilet bowl, extending backwards from the toilet, above floor level; however, this will only be applicable in countries which use this toilet drain configuration.

Summary of the invention

Within this specification and the appended claims, references to directions, such as "horizontal", "downwards" etc. refer to the equivalent direction in an assembled and fitted toilet. Words such as "rearwards" and "behind" refer to the direction opposite to the direction in which a user of an assembled and fitted toilet would face while sitting on the toilet.

According to a first aspect of the present invention there is provided a toilet comprising a toilet bowl, a passage which extends from the base of the toilet bowl to a drain outlet, and a gate, the gate having an open position which allows water within the toilet bowl to flow out of the drain outlet by way of the passage and a closed position in which the gate retains a continuous body of water within the toilet bowl and a portion of the passage, up to a fill level, the toilet further comprising a divider arranged to close off the passage above the fill level and to extend below the fill level at a location intermediate the toilet bowl and the water line where the surface of the continuous body of water contacts the gate, to form a water trap in use when the gate is in the closed position and water is retained up to the fill level. As the passage extends from the base of the toilet bowl and the gate allows water within the toilet bowl to flow out of the drain outlet when the gate is open, there is no need for the substantial volume of flush water which functions to carry solids within the toilet bowl through the S-shaped water trap of a conventional toilet during flushing.

Nevertheless, the provision of a divider which is arranged to close off the passage above the fill level and to extend below the fill level, into the continuous body of water in use, to form a water trap, prevents unpleasantly smelling gas from diffusing from the drain outlet to the toilet bowl in the gas phase. The toilet should preferably be formed and arranged so that there is no other path for gas from the drain outlet to diffuse into the surrounding atmosphere in the gas phase.

Preferably, the gate comprises a flap having a hinged base. The hinged base is typically attached to the interior base of the passage. The hinged base may comprise a jointed or flexible hinge, for example, the flap may include a flexible portion which functions as a hinge, flexibly attaching the flap to the interior base of the passage. Typically, in the open position, the flap extends horizontally, or horizontally downwards, from the hinged base, towards the drain outlet, to allow water to flow from the toilet bowl through the passage over the gate to the drain outlet. Preferably, in the closed position, the flap extends generally vertically from the hinged base. The flap is preferably located within the passage and the divider is preferably located entirely intermediate the flap and the toilet bowl. However, the hinged base of the flap may be located underneath the divider, or within the toilet bowl, or between the toilet bowl and the divider.and extends under the divider towards the drain outlet.

Where the gate comprises a flap, the gate preferably further comprises flexible sealing members which extend from the flap to the adjacent walls of the passage and which flex in use as the flap moves between the open and closed positions. This arrangement has the advantage that there need not be a sliding contact between the side walls of the flap and the walls of the passage. The flexible sealing members are typically in sealing engagement with the walls of the passage at an orientation which is intermediate the orientation which the flap adopts in the open position and the orientation which the flap adopts in the closed position, for example, the join between the flexible sealing members and the interior of the passage may extend from the hinged base of the flap at an angle of between 30° and 75°, and preferably around 45°, from the horizontal, towards the drain outlet. The flexible sealing members may be integral with the flap. The flexible sealing members may be elastic. The flexible sealing members may comprise folds. The flap and flexible sealing members may be formed as an integral member comprising one or more folds. In a preferred embodiment, the gate comprises a flap and flexible sealing members on either side of the flap, wherein the flap and flexible sealing member are formed as an integral piece of material, such as a folded sheet of elastomeric material. Preferably, the base and sides of the gate are integral with, or extend into, the wall of the passage. As discussed further below, the gate (e.g. flap and flexible sealing members) may extend into a recess between passage sections.

However, alternative gates may be employed. For example, the gate may comprise a flap having a generally vertical hinge, or a wall which extends above the fill level in the closed position but does not extend above the base of the passage in the open position, to allow water to flow from the toilet bowl through the passage to the drain outlet.

Typically, the toilet bowl and passage are formed and arranged to provide a continuous downhill path for water to flow from the toilet bowl through the passage to the drain outlet when the gate is in the open position. Typically, the toilet bowl and passage are formed and arranged to provide a continuous path for water to flow from the toilet bowl to the drain outlet at a mean angle of between 5° and 20° below the horizontal.

The drain outlet may be provided behind the toilet below the base of the toilet bowl and above a floor contacting base of the toilet. The drain outlet may comprise a section of pipe facing generally rearwards from the toilet. Thus, the toilet can be fitted to the toilet fitments which are in common use in the UK and some other territories in which a soil pipe is provided which extends from behind the toilet, below the toilet bowl and above floor level. However, the drain outlet may be provided in a different configuration for use with different toilet fittings appropriate to the market where the toilet is to be sold.

Preferably, the toilet comprises a bowl portion and an adaptor pipe portion, wherein the bowl portion comprises the toilet bowl and divider, wherein the passage is formed at least in part by the adaptor pipe portion and is typically also formed at least in part by a passage section of the bowl portion which extends from the divider. Typically, the adaptor pipe portion and passage section of the bowl portion are attachable in an abutting relationship. Typically also, the adaptor pipe portion is attachable to a soil pipe in an abutting relationship. This allows for modular construction of the toilet. The bowl portion and adaptor pipe portion may be detachable to facilitate repair and/or maintenance of the gate.

Preferably, the adaptor pipe portion and bowl portion (typically the passage section of the bowl portion) are sealable together by cooperating flanges, which typically extend rearwards and upwards, for example at an angle of around 45° to the horizontal.

Preferably, the gate is arranged to be fitted between the adaptor pipe portion and the bowl portion. For example, either or both of the bowl portion abutting end of the adaptor pipe portion and the adaptor pipe portion abutting end of the bowl portion may comprise a recess for receiving the gate. The base and sides of the gate may be made from an elastic (e.g. elastomeric) material formed and arranged to locate within the recess. Accordingly, the base and sides of the gate are typically sealed into the said recess in an assembled toilet. In a preferred embodiment, the gate comprises a said flap and flexible sealing members formed of an elastomeric material and arranged to extend into and be sealed within said recess.

The gate (e.g. a flap and flexible sealing members) is typically made from an elastomeric material such as silicon rubber or a flexible plastics material such as flexible polyvinyl chloride, acrylonitrile butadiene styrene or polyethylene.

Typically, the passage comprises a first passage region extending under the divider and a second passage region extending from the divider towards the drain outlet, wherein the ceiling of the second passage region is higher than the fill level so that there is an air space above the body of water in the second passage region, extending up to the divider.when the gate is closed and the toilet is filled with water up to the fill level.

The gate (e.g. a flap) may contact the divider on the side of the divider towards the drain outlet. In this case, the gate preferably contacts the divider below the fill level and extends above the fill level on the side of the divider towards the drain outlet such that there is a water-filled gap between the divider and the water line where the surface of the continuous body of water contacts the gate. A benefit of the claimed arrangement is that the gate need not form a gas tight seal between the drain outlet and the toilet bowl. This is advantageous as it is difficult to form a gas tight seal which will be reliable in the long term, particular if the gate may be fouled in use.

Typically, the gate extends above the fill level but below the ceiling of the second passage region when the gate is in the closed position. Accordingly, a continuous air space may extend from the drain outlet to the divider.above the retained water, when the gate is closed and the toilet bowl is filled up to the fill level.

The divider is preferably fixed. For example, the divider may be integral to the toilet bowl. Typically, the toilet bowl and divider.and optionally the passage, or a portion of the passage, are an integrated (preferably monolithic) unit formed, for example, from a plastics material or preferably a ceramic. The divider may be demountable to facilitate replacement.

The surface of the divider which faces the toilet bowl typically forms part of the surface of the toilet bowl, although the divider could be recessed from the toilet bowl, within the passage. Typically, the vertical distance between the base of the divider and the base of the passage, underneath the divider, is at least 5cm to facilitate the outflow of solids material.

The base of the divider is typically rounded to facilitate cleaning and the flow of water underneath the divider.

The toilet bowl has a rim. A water conduit may be provided around the periphery of the toilet bowl, near the rim, the water conduit comprising a plurality of apertures through which water is directed down the sides of the bowl to rinse the sides of the toilet bowl for a period of time and refill the toilet bowl up to the fill level when the toilet is flushed. A removable conduit may be provided in which case the toilet comprises a water outlet for supplying flush water to a removable conduit, and the toilet may be provided as a part of a kit further comprising one or more removable, generally ring-shaped, water conduits having a plurality of apertures around the ring.

The gate should be movable from the closed position to the open position responsive to operation of a manually operable flush control, such as a flush button or handle. Preferably, a flush mechanism is operable to cause the gate to move from the closed position to the open position for a first period of time following operation of a manually operable flush control and then to cause (e.g. allow) the gate to move from the open position to the closed position. Preferably also, the flush mechanism is operable to cause water to flow into the toilet bowl, for example, by way of said apertures in said water conduit, for a second period of time, which is longer than the first period of time. The flush mechanism may be operable to cause water to flow into the toilet bowl, for example, by way of said apertures, for a second period of time, which is longer than the first period of time, by causing water to flow into the toilet bowl until a water level sensor indicates that the water level has reached the fill level.

The flush mechanism may be mechanical. For example, a mechanical linkage may be provided between the manually operable flush control and the gate.

The flush mechanism may comprise a hydraulic actuator operable to move the gate between the closed position and the open position, and a hydraulic line operably linked to the manually operable flush control and the hydraulic actuator. Accordingly, the flush mechanism preferably comprises a pressurisable chamber in fluid communication with the hydraulic line, the pressure within which is changeable by operation of the manually operable flush control. Preferably, mains water is used as the hydraulic fluid to transmit hydrostatic force to the hydraulic actuator. This is advantageous as the toilet anyway requires a water supply and further water can be supplied in the event of any minor internal leakage.

Preferably, the flush mechanism is operable to increase the pressure within the pressurisable chamber in response to manual operation of the flush control. Preferably also, the pressurisable chamber is a chamber within a piston cylinder and the manually operable flush control is operably linked to the piston cylinder. For example, the flush mechanism may comprise a flush rod having first and second ends, the first end of which is connected to a flush button by way of a biasing member (e.g. a spring), and the second end of which is attached to or forms a piston within a piston cylinder.

Preferably, the hydraulic actuator is a piston cylinder.for example a piston cylinder comprising a piston which extends from the piston cylinder and is mechanically linked to the gate. Where the gate is a flap, the piston cylinder preferably comprises a piston driving chamber in fluid communication with the hydraulic line, and a piston mechanically linked to a strut extending to the underside of the gate, the piston cylinder further comprising a biasing member which acts to reduce the volume of the piston driving chamber.

The hydraulic actuator may comprise an inflatable chamber in fluid communication with the hydraulic line, which inflatable chamber has an inflated state and a deflated state, wherein the gate is mechanically linked to the inflatable chamber so that the gate adopts the open position or the closed position when the inflatable chamber is in the inflated state and the gate adopts the closed position or open position respectively when the inflatable chamber is in the deflated state.

The hydraulic actuator may be integral to the gate. For example, where the hydraulic actuator comprises an inflatable chamber in fluid communication with the hydraulic line, the inflatable chamber may be integral to the gate and the gate may be formed and arranged so that the gate adopts the closed position or the open position when the inflatable chamber is in the inflated state and the gate adopts the open position or the closed position respectively when the inflatable chamber is in the deflated state."

Preferably, a pressure equalising device is provided which is operable to restore pressure in the hydraulic actuator (e.g. within the piston driving chamber where relevant) to an equilibrium pressure a period of time after operation of the manually operable flush control. Preferably, the pressure equalising device is formed and arranged so that pressure within the hydraulic actuator either does not change, or changes only slowly, for a period of time and then returns rapidly to equilibrium to return the gate rapidly to the closed position. Typically, the flush mechanism is arranged so that operation of the manually operable flush control increases the pressure within the pressurisable chamber, and the pressure equalising device is operable to cause pressure to decrease rapidly to equilibrium pressure a period of time after operation of the manually operable flush control, in order to return the gate to the closed position.

As the hydraulic actuator is operably linked to the pressurisable chamber via the hydraulic line, the pressure equalising device may be in fluid communication with one or more of the hydraulic actuator (e.g. the piston driving chamber, where relevant), the hydraulic line and the pressurisable chamber. The pressure equalising device may comprise a slowly leaking member, such as a member which is porous or has one or more apertures therethrough. In a preferred embodiment, the pressurisable chamber is formed in a piston cylinder between a first piston, which is operably linked to the manually operable flush control, and a second piston, which is biased to compress the pressurϊsable chamber, wherein the second piston divides the pressurisable chamber from a further chamber within the piston cylinder, wherein the further chamber comprises one or more orifices through which water can slowly leak in use. The second piston may be biased to occlude a pressure equalising port of the piston cylinder, and moveable slowly as a result of water passing slowly out of the further chamber, enabling the second piston to move slowly to a position where it brings the pressurisable chamber into fluid communication with the pressure equalising port, to enable pressure within the pressurisable chamber to rapidly return to the equilibrium pressure.

Preferably, the flush mechanism is operably linked to a valve which is operable for a period of time responsive to the operation of the flush control to supply water to the toilet bowl, for example through the said water conduit or replaceable spray member. The manually operable flush control may be arranged to open the valve responsive to a drop in the water level within the toilet bowl or passage. Preferably, the flush mechanism is arranged to open the valve by a mechanical arrangement responsive to manual operation of the manually operable flush control and to close the valve responsive to detection by a water level sensor that the level of water within the toilet bowl or passage has reached a fill level. The level sensor may comprise a float. The flush mechanism may comprise a lever arm having first and second ends with a pivot therebetween, the first end being mechanically attached to the float (e.g. by a connecting rod) and the second end being mechanically attached to the valve (e.g. by a connecting rod). Where the flush mechanism comprises a said flush rod, the flush rod may be mechanically connected to the said lever arm, for example, by way of a toggle hook which demountably engages with a spigot which is attached to the said lever arm intermediate the first end and the pivot, to open the valve responsive to manual operation of the flush control.

According to a second aspect of the present invention there is provided a toilet comprising a toilet bowl, and a passage which extends from the base of the toilet bowl to an outlet located to the rear of the toilet, the toilet further comprising a divider arranged to close off an upper portion of the passage between the toilet bowl and outlet.

The outlet may be adapted for direct attachment to a soil pipe, or for attachment to an end of an adaptor pipe, for indirectly attaching the toilet to a soil pipe. The toilet may be provided as a part of a kit further comprising an adaptor pipe having a gate attached thereto, or a fitting for receiving a gate (and preferably also a gate receivable in said fitting), the kit being assemblable to form a toilet according to the first aspect of the invention.

Preferably, the outlet and the said end of the said adaptor pipe are adapted to join in an abutting relationship and either or both of the outlet and the said end of the said adaptor pipe comprise a recess for receiving and sealedly retaining a gate.

The toilet may comprise an aperture extending rearwards from the toilet bowl under the divider into a passage, the passage having an interior surface which extends higher than the uppermost point of the aperture.

Typically, the toilet bowl, passage and divider are formed as an integrated (preferably monolithic) unit.

Preferably, the outlet is located below the base of the toilet bowl, above a floor contacting base of the toilet, rearwards of the toilet bowl. This enables the toilet to be fitted to a toilet fitment having a soil pipe extending from the rear of the toilet, above floor level.

Preferred features of the toilet and gate correspond to those discussed above in relation to the first aspect of the invention.

Description of the Drawings

An example embodiment of the present invention will now be illustrated with reference to the following Figures in which:

Figure 1 is a sectional view of a toilet according to the present invention, while filled to a fill level;

Figure 2 is a schematic diagram of a flush control mechanism for the toilet of Figure 1 ; Figure 3 is a cross-section through an adaptor pipe with a fitted flap in the raised position;

Figure 4 is a cross-section through a bowl portion;

Figure 5 is a cross-section through the adaptor pipe of Figure 3 with a fitted flap in the lowered position;

Figure 6 is a perspective view of the passage of a toilet according to Figure 1 cut away to show the gate in the raised (closed) position; and

Figure 7 is a perspective view of the passage of a toilet according to Figure 1 cut away to show the gate in the lowered (open) position.

Detailed Description of an Example Embodiment

With reference to Figure 1, a toilet 1 comprises a ceramic unit 2 and rear housing 4, which has a manually operable flush button 6 (functioning as the flush control) mounted thereon, and encloses the majority of a flush control mechanism which is described further below. The ceramic unit is shaped to define a toilet bowl 8 having an interior base 10, interior wall 12 and rim 14 with an overhanging peripheral lip 16 which lip retains a spray ring 18, the spray ring being formed from an injection moulded plastics material and comprising a plurality of apertures (not shown).

The interior wall of the ceramic unit includes a baffle 19 (functioning as the divider) which separates the toilet bowl from a first pipe section 20. An aperture 22 extends under the baffle into the first pipe section to allow the passage of water and solids from the toilet bowl into the first pipe section in use. The first pipe section is sealedly attached to a second pipe section 24 by cooperating flange members 26, 28 on the first and second pipe sections, respectively. The cooperating flange members extend rearwards and upwards at an angle of around 45° to the horizontal. The second pipe section extends to a drain outlet 30 and, together with the first pipe section, forms a passage extending from the base of the toilet bowl to the drain outlet.

Within the passage, a flap 32 (functioning as the gate) is located within the passage and is pivotably attached to the base of the passage by a hinge 34 and sealedly attached to the passage walls to either side of the flap by flexible sealing members 35, illustrated in Figure 3. The flap is deployable from a raised position (functioning as the closed position), in which the flap extends generally vertically to a lowered position (functioning as the open position), in which the flap extends horizontally rearwards and slightly downwards, by a flap actuating slave cylinder 36 (functioning as the hydraulic actuator). The slave cylinder includes a piston 38 (shown in Figure 2) having a piston rod 40 which extends out of the cylinder to a crosshead 42 from which a strut 44 extends to a hinge 46 on the rear surface of the flap. The piston is biased by a spring 48 within the cylinder so that, by default, the flap is maintained in the raised position.

Figure 2 is a schematic diagram of components of a flush control mechanism, located at least partially within the rear housing. The flush button is connected via a spring 50 to a flush rod 52. The spring biases the flush button upwards and the flush button is pressable downwards to a position limited by an endstop 54. The flush rod extends downwards and its lower extremity functions as a first piston 56 within a hydraulic master cylinder 58, the hydraulic master cylinder further comprising a second piston 60 with a pressurisable chamber defined between the first and second piston cylinders. The master cylinder has a slave piston driving port 62, located between the first and second pistons in fluid communication with a hydraulic line 64; a leak controlling port 66 located at the base of the cylinder, in fluid communication with an unpressurised water reservoir 68; and a discharge port 70 which is occluded by the second piston when the flush control mechanism is in its rest state prior to use. The second piston is biased upwards by a spring 74 located within a further chamber which is divided from the pressurisable chamber by the second piston and which is in fluid communication with the leak controlling port. The hydraulic line extends to and is in fluid communication with a piston driving chamber 76 of the slave cylinder.

The flush rod is pivotably mounted to a toggle hook 78 which engages on a spigot 80 located on a lever arm 82, the said lever arm having a pivot 84. The lever arm is linked by a connecting rod 86 extending from the first end, on the same side of the pivot as the spigot, to a float 88 (functioning as a water level sensor) located within a float chamber and in sensing communication with water within the passage by means of a hydraulic line 89 which extends to a sensing port in fluid communication with the bottom of the toilet bowl, in the region of the flap. The bottom of the float chamber is level with the sensing port, so that the water level in the float chamber is the same as the water level in the toilet bowl and passage. The second end of the lever arm is mechanically linked to a fill valve 90 which is openable to allow water to pass from the main water supply through the fill valve inlet 92 to the fill valve outlet 94 and then into the spray ring and out through the apertures located around the spray ring and down the sides of the toilet bowl. The fill valve includes a sealed bore with a ferrous slug therein which, when pulled upwards when the second end of the level arm is raised, opens a magnetically actuated pilot allowing water to flow from the inlet of the fill valve to the outlet. A pipe interrupter valve 95 is provided between the fill valve outlet and the spray ring to prevent siphonage and/or backflow by creating an open vent to the surrounding atmosphere.

With reference to Figures 3 and 4, the ceramic unit, baffle and the first pipe section (together functioning as the bowl portion) are typically formed as a monolithic unit 96, illustrated in Figure 4. The second pipe section (functioning as the adaptor pipe portion) includes a first end 98 which is adapted to be attached to a soil pipe and so function as the drain outlet, and a second end 100 (functioning as the bowl portion abutting end of the adaptor pipe portion) which includes a shallow recess 102.

In order to assemble the toilet, the second pipe section is plumbed to a soil pipe. The flap actuating slave cylinder and hydraulic line are fitted to the second pipe section. A piece of elastomeric material comprising both the flap and flexible sealing members, and including a number of flexible hinges, is located in the shallow recess. The gate initially stands proud of the recess. The ceramic unit is then fitted to the second pipe section by abutting the second end of the second pipe section and the open end of the first pipe section (which functions as the pipe adaptor abutting end of the bowl portion). The flanges are sealed together, for example with bolts. The edges of the piece of elastomeric material, which extend into the shallow recess, are compressed, forming a seal between the flap and the passage.

The ceramic unit includes a ground engaging base (not shown) which defines the height at which the first pipe section extends above the floor onto which the toilet is fitted. The rear housing is mounted behind and above the ceramic unit with the float mechanically linked to the first end of the lever arm and the slave cylinder connected to the hydraulic line. The spray ring may, for example, be formed as a silicon rubber moulding having an inlet for receiving water from the fill valve. The master cylinder, hydraulic line and slave cylinder may be formed as an integral unit, e.g. as a single moulding from a plastics material. Between flushes, the flap adopts the raised position illustrated in Figures 3 and 6, and the toilet bowl remains filled up to a fill level 104 with a continuous body of water 106 which extends from the toilet bowl into the passage, to the flap, up to a water line 108 on the surface of the flap. A gas space 110 above the water line, within the passage, is in gaseous communication with the drain outlet and so will accumulate unpleasantly smelling gases, from the drain. The baffle depends from the roof of the passage into the continuous body of water, to below the fill level, thereby forming a water trap separating the gas space from the toilet bowl. Accordingly, provided that the passage has been sealed correctly to the drain outlet, gases from the drain cannot penetrate the surrounding atmosphere except by dissolving in the body of water and evaporating from within the toilet bowl.

When the flush button is depressed by a user, the button engages with the endstop, and the manual action of the user compresses the spring. The spring exerts a downwards force on the flush rod and thus the first piston. Water in the pressurisable chamber within the master cylinder is thereby pressurised and displaced into the hydraulic line. Water is concomitantly displaced from the hydraulic line into the piston driving chamber of the slave cylinder where it moves the piston against the biasing spring, retracting the strut and causing the flap to pivot around its hinge from the raised position to the lowered position, illustrated in Figures 5 and 7. As a result, the continuous body of water drains through the passage, over the gate and out of the drain outlet. The aperture under the baffle is dimensioned to provide sufficient size for solid waste to flow out of the toilet bowl and along the passage. As the body of water drains through the passage and the depth of water within the toilet bowl and passage drops to near zero, the float also drops within the float chamber.

The downward motion of the flush rod simultaneously causes the toggle hook to pull down on the spigot, thereby pulling the first end of the lever arm down and the second end of the lever arm up, opening the fill valve and allowing water to flow from the mains water supply, through the fill valve, to the spray ring. Water flows from the spray ring down around the periphery of the toilet bowl. Because the flap and baffle arrangement does not require water within a fixed water trap to be displaced, the water which flows down from the spray ring is not required to provide fluid kinetic energy. Water is required only to clean and refill the toilet bowl. As the flush rod continues downwards, the toggle hook goes over centre and disengages from the spigot, allowing movement of the level arm to be disengaged from movement of the flush rod.

As a result of the pressure within the pressurisable chamber, water flows slowly out of the master cylinder through the leak controlling port. The second piston gradually moves downwards at a rate which can be accurately controlled by appropriate selection of the diameter of the leak controlling port and the spring modulus of the various springs. The simultaneous gradual loss of pressure is not sufficient to significantly affect the slave cylinder and the position of the flap. However, once the second piston moves sufficiently far towards the base of the master cylinder, it uncovers the discharge port, through which water in the pressurisable chamber rapidly flows, causing sudden depressurisation of the pressurisable chamber of the master cylinder, the hydraulic line and the piston driving chamber of the slave cylinder. Accordingly, as a result of the action of the biasing spring within the slave cylinder, the flap returns to the raised position. Water flows into the toilet bowl through the apertures in the spray ring and the water level within the bowl and passage rises. The float rises with the water level in the passage and, once the water level has reached a fill level, the rising float raises the first end of the lever arm and pushes down the second end of the lever arm to cut off the water flow to the spray ring.

Once the user has released the flush button, the flush rod rises, the toggle hook reengages, the second piston rises back up to again cover the discharge port ,and the master cylinder refills leaving the toilet ready for the next flush.

A user can select a partial flush by releasing the flush button before the entire continuous body of water has flowed to the drain outlet, allowing the flap to rise. In this case, water will continue to flow into the bowl through the spray ring until the water level sensing mechanism determines that the fill level has been reached.

Accordingly, the toilet requires less water than a conventional toilet which includes an S-shaped water trap and requires a significant volume of water to provide kinetic energy to displace water within the toilet bowl through the water trap. Nevertheless, the water trap formed in use by the flap and baffle prevents gas from passing from the drain outlet into the surrounding atmosphere while the toilet is filled with water up to the fill level. Thus, the water within the passage forms a gas seal and so the flap itself can retain water within the bowl without requiring to form a gas tight seal around its entire periphery.

The toilet can be fitted to a conventional toilet fitting in which a drain pipe is provided extending rearwards from the toilet, below the toilet bowl and above floor level. The flush button and general configuration of the toilet is similar to conventional toilets which facilitates acceptance of the product by the general public.

As the flap moves from the raised position to the lowered position and vice versa, the flexible hinges flex. As the flexible sealing members are fixed to the passage walls, a reliable seal is readily formed between the flap and the passage. It would be difficult to obtain a reliable seal if the edges of the flap had to slide against the sides of the passage, and it would be necessary to use a passage with a non-circular cross- section. As the flexible sealing members are sealed to the passage walls at an angle of 45° to the horizontal, which is approximately half way between the orientation of the flap in the raised position and the orientation of the flap in the lowered position, the force on the flexible sealing members and the surface area of the flexible sealing members are minimised. In some embodiments, the second pipe section is demountable from the first pipe section and drain outlet to facilitate replacement of the flap.

The spray ring can be removed and replaced readily. Otherwise, manual intervention is not required except for ongoing cleaning. Where required, the fill level can be adjusted by varying the mechanical connection between the float and the first end of the lever rod.

One skilled in the art will appreciate that the flush mechanism, which is operable to open the gate for a period of time and to introduce water to the toilet bowl for a longer period of time, may readily be replaced by alternative mechanisms which have the same effects, including purely mechanical mechanisms and/or electrical mechanisms.

In alternative embodiments, the flap may be replaced by an alternative gate, such as a gate having two or more parts; one or more gate portions with vertical hinges; a gate comprising a wall which is raised or lowered to allow water to flow to the drain outlet in the open position; and so forth. Where the gate is a flap with a hinge along the base, the hinge may be located underneath the divider or even within the toilet bowl. In this case, the invention envisages that the top of the flap would extend rearwards of the divider so that there is at least a small body of water between where the water line contacts the flap and the divider, so that the body of water forms a water trap.

Although the divider has been illustrated as a fixed, integral part of a toilet bowl, the divider may take the form a demountable baffle, a moveable baffle which is, for example, raised as part of the flush mechanism and/or a baffle which is recessed within the passage. The divider may also comprise an elongate passage portion.

Further modifications and variations may be made within the scope of the invention herein disclosed.

Claims

1. A toilet comprising a toilet bowl, a passage which extends from the base of the toilet bowl to a drain outlet, and a gate, the gate having an open position which allows water within the toilet bowl to flow out of the drain outlet by way of the passage and a closed position in which the gate retains a continuous body of water within the toilet bowl and a portion of the passage, up to a fill level, the toilet further comprising a divider arranged to close off the passage above the fill level and to extend below the fill level at a location intermediate the toilet bowl and the water line where the surface of the continuous body of water contacts the gate, to form a water trap in use when the gate is in the closed position and water is retained up to the fill level.

2. A toilet according to Claim 1 , wherein the gate comprises a flap having a hinged base and wherein, in the open position, the flap extends horizontally, or horizontally downwards, from the hinged base, towards the drain outlet, to allow water to flow from the toilet bowl through the passage over the gate to the drain outlet.

3. A toilet according to Claim 2, wherein the flap is located within the passage and the divider is located entirely intermediate the flap and the toilet bowl.

4. A toilet according to Claim 2 or Claim 3, wherein the hinged base of the flap is located underneath the divider, or within the toilet bowl, or between the toilet bowl and the divider, and extends under the divider towards the drain outlet.

5. A toilet according to any one of Claims 2 to 4, wherein the gate further comprises flexible sealing members extending from the flap to the adjacent walls of the passage.

6. A toilet according to Claim 5, wherein the flap and flexible sealing members are formed as an integral piece of elastomeric material.

7. A toilet according to any one preceding Claim, wherein the toilet comprises an adaptor pipe portion and a bowl portion having a passage section, the passage is formed at least in part by the adaptor pipe portion and the said passage section, the adaptor pipe portion and the bowl portion are attached to each other in an abutting relationship, either or both of the adaptor pipe portion abutting end of the bowl portion and the bowl portion abutting end of the adaptor pipe portion comprise a recess for receiving the gate, and the base and sides of the gate are sealed into the said recess.

8. A toilet according to any one preceding Claim, wherein the toilet bowl and passage are formed and arranged to provide a continuous downhill path for water to flow from the toilet bowl through the passage to the drain outlet when the gate is in the open position.

9. A toilet according to any one preceding Claim, wherein the drain outlet is provided behind the toilet below the base of the toilet bowl and above a floor contacting base of the toilet.

10. A toilet according to any one preceding Claim, wherein the passage comprises a first passage portion extending under the divider and a second passage portion extending from the divider towards the drain outlet, wherein the ceiling of the second passage portion is higher than the fill level so that there is an air space above the body of water in the second passage portion, extending up to the divider, when the gate is closed and the toilet is filled with water up to the fill level.

11. A toilet according to Claim 10, wherein the gate extends above the fill level but below the ceiling of the second passage portion when the gate is in the closed position.

12. A toilet according to any one preceding Claim, wherein the divider is integral to the toilet bowl.

13. A toilet according to any one preceding Claim, wherein the toilet bowl comprises a rim and a water conduit is provided around the periphery of the toilet bowl, near the rim, the water conduit comprising a plurality of apertures through which water is directed down the sides of the bowl to rinse the sides of the toilet bowl for a period of time and refill the toilet bowl up to the fill level when the toilet is flushed.

14. A toilet according to any one of Claims 1 to 12, wherein the toilet bowl comprises a rim and a water outlet for supplying flush water to a removable conduit.

15. A toilet according to any one preceding Claim, wherein the toilet comprises a flush mechanism which is operable to cause the gate to move from the closed position to the open position for a first period of time following operating of a manually operable flush control and then to cause the gate to move from the open position to the closed position.

16. A toilet according to Claim 15, wherein the flush mechanism is operable to cause water to flow into the toilet bowl, for example, by way of said apertures in said water conduit, for a second period of time, which is longer than the first period of time.

17. A toilet according to Claim 15 or Claim 16, wherein the flush mechanism comprises a hydraulic actuator operable to move the gate between the closed and open position and a hydraulic line operably linked to the manually operable flush control and hydraulic actuator.

18. A toilet according to Claim 17, wherein mains water is used as the hydraulic fluid to transmit hydrostatic force to the hydraulic actuator.

19. A toilet according to Claim 17 or Claim 18, wherein the hydraulic actuator is a piston cylinder which is mechanically linked to the gate.

20. A toilet according to any one of Claims 17 to 19, wherein the flush mechanism comprises a pressurisable chamber in fluid communication with the hydraulic line, the pressure within which is changeable by operation of the manually operable flush control.

21. A toilet according to any one of Claims 17 to 20, wherein a pressure equalising device is provided which is operable to restore pressure in the hydraulic actuator to an equilibrium pressure a period of time after operation of the manually operable flush control.

22. A toilet according to Claim 21 , wherein the pressure equalising device is formed and arranged so that pressure within the hydraulic actuator returns to equilibrium at most slowly for a period of time and then returns rapidly to equilibrium to return the gate rapidly to the closed position.

23. A toilet according to Claim 21 or Claim 22, wherein the pressure equalising device comprises a slowly leaking member

24. A toilet according to any one of Claims 21 to 23, wherein the pressurisable chamber is a chamber within a piston cylinder and the manually operable flush control is operably linked to the piston cylinder.

25. A toilet according to Claim 24, wherein the pressurisable chamber is formed in a piston cylinder between a first piston which is operably linked to the manually operable flush control and a second piston which is biased to compress the pressurisable chamber wherein the second piston divides the pressurisable chamber from a further chamber within the piston cylinder.the further chamber comprising one or more orifices, wherein the second piston is biased to occlude a pressure equalising port of the piston cylinder, and moveable slowly as a result of water passing slowly out of the further chamber through the said one or more orifices, enabling the second piston to move slowly to a position where it brings the pressurisable chamber into fluid communication with the pressure equalising port, to enable pressure within the pressurisable chamber to rapidly return to the equilibrium pressure.

26. A toilet according to any one of Claims 15 to 25, wherein the flush mechanism is operably linked to a valve which is openable for a period of time responsive to operation of the flush control to supply water to the toilet bowl, wherein the mechanism is operable to close the valve responsive to detection by a level sensor that the level of water within the toilet bowl or passage has reached a fill level.

27. A toilet according to Claim 26, wherein the flush mechanism comprises a lever arm having opposite first and second ends with a pivot therebetween, the first end being mechanically attached to a float, functioning as the level sensor, and the second end being mechanically attached to the said valve.

28. A toilet comprising a toilet bowl, and a passage which extends from the base of the toilet bowl to an outlet located to the rear of the toilet, the toilet further comprising a divider arranged to close off an upper portion of the passage between the toilet bowl and outlet.

29. A toilet according to Claim 28, comprising an aperture extending rearwards from the toilet bowl under the divider into a passage, the passage having an interior surface which extends higher than the uppermost point of the aperture.

30. A toilet according to Claim 28 or Claim 29, wherein the toilet bowl, passage and divider are formed as an integrated unit.

31. A toilet according to any one of Claims 28 to 30, wherein the outlet is located below the base of the toilet bowl, above a floor contacting base of the toilet, rearwards of the toilet bowl.

32. A kit comprising a toilet according to any one of Claims 28 to 31 , further comprising an adaptor pipe having a gate attached thereto, or a fitting for receiving a gate.

33. A kit according to Claim 32, wherein the kit further comprises a gate and an adaptor pipe having an end, the said end of the adaptor pipe and the outlet ^' are adapted to join in an abutting relationship, and either or both of the said end of the adaptor pipe and the outlet comprise a recess for receiving and sealedly retaining the gate.

34. A kit according to Claim 33, wherein the gate comprises a flap and flexible sealing members extending from either side of the flap, formed as a piece of elastomeric material arranged to cooperate with the recess.