Field

[0001] The present invention relates to a chamber for an odour extraction device in toilet cisterns.

[0002] The invention has primarily been developed for use in toilets in fixed homes and will be described hereinafter with reference to this application. However, the invention is not limited to this particular use and is also applicable for use with toilets in other environments such as marine vessels; mobile homes; campervans; recreational vehicles; caravans; portable buildings and portable toilets.

Background

[0003] The Applicant’s international PCT patent application Nos PCT/AU2007/000003 (WO 2007/079/079524) and PCT/AU2018/000006 (WO 2018/140998) disclose embodiments of an odour extraction device for gravity flushing and siphonic flushing toilet pans. The disclosed odour extraction devices include a one-way valve to prevent unpleasant odours from flowing from the sewer back to the toilet pan. The disclosed odour extraction devices utilise a suction fan to draw gas from within the pan and expel it through a duct into the pan’s flushing outlet pipe. The gas then flows through the pan’s flushing outlet pipe into the sewer.

[0004] The performance of the disclosed odour extraction device can vary depending on the installation. Further, the installer is required to adequately seal all gaps in the toilet cistern, which is difficult, particularly with in-wall toilet cisterns. Atmospheric leaks from the flush buttons, water inlet valves and the join between the cistern lid and cistern cause inefficiencies in the odour extraction devices, meaning that devices must operate at a higher speed to achieve the desired odour extraction effect, which draws more electric power and is loud for the operator. In some cases, the air leakage prevents the toilet from being odourless, despite having a high- powered fan. Therefore, it would be desirable to maximise air flow from the odour extraction device through the toilet overflow pipe. It is an object of the present invention to provide a chamber that mitigates at least one of the above disadvantages. Summary of Invention

[0005] An aspect of the present invention provides a toilet cistern to be used with a toilet pan, the cistern including: a tank to hold water; an overflow pipe in fluid communication with the tank and the toilet pan; a chamber member surrounding at least a portion of the overflow pipe, the chamber member having a chamber body defining a cavity and an inlet and an outlet, the inlet being in fluid communication with the overflow pipe; and a fan assembly located within the tank, the fan assembly having a fan body with an inlet and an outlet, said fan assembly inlet being in fluid communication with the fan body outlet so that gas from the toilet pan is drawn through the overflow pipe, into the chamber and fan assembly, and expelled from the outlet of the fan assembly.

[0006] In the preferred embodiment, the overflow pipe has first and second openings, the first opening of the overflow pipe being in fluid communication with the toilet pan, and the second opening of the overflow pipe being in fluid communication with the tank.

[0007] Preferably, the chamber outlet is sealingly engaged with the fan assembly inlet.

[0008] Preferably, the chamber body has at least one aperture to allow airflow into the chamber from the tank.

[0009] In the preferred embodiment, the at least one aperture is sized to allow a first airflow into the chamber and the second opening of the overflow pipe is sized to allow a second airflow into the chamber and wherein the first airflow is less than the second airflow.

[0010] Preferably, the chamber member outlet is substantially annular.

[0011] Alternatively, the chamber member outlet is rectangular. [0012] Preferably, the at least one aperture includes a plurality of apertures spaced apart to at least partially circumscribe the chamber member outlet.

[0013] Preferably, the plurality of apertures is disposed on a plane generally parallel to the chamber outlet.

[0014] Preferably, wherein the tank further includes a water supply inlet to fill the tank with water.

[0015] Additionally, the tank further includes a water level governor to selectively provide a predetermined water level.

[0016] Preferably, the predetermined water level is between the chamber member inlet and the second opening in the overflow pipe.

[0017] Preferably, the water level governor is attached to the tank.

[0018] Preferably, the predetermined water level provides a seal between the overflow pipe and the chamber member.

[0019] Preferably, the overflow pipe is selectively adjustable to position the second opening above the predetermined water level.

[0020] Preferably, the chamber member inlet is substantially annular and of greater area than the chamber member outlet.

[0021] Alternatively, the chamber member inlet is substantially rectangular and of greater area than the chamber member outlet.

Brief Description of Drawings

[0022] A preferred embodiment of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein:

[0023] Fig. 1 is a schematic cross-sectional view of an embodiment of a chamber located within a toilet cistern. [0024] Fig. 2 is a perspective view of the chamber.

[0025] Fig. 3 is perspective view of the chamber together with a fan assembly.

[0026] Fig. 4 is a partial cross-sectional view of the chamber and fan assembly.

Description of Embodiments

[0027] Figure 1 shows a cistern 1 according to a preferred embodiment (without a cistern lid). The cistern 1 has a tank 10 to hold water, as well as a water supply inlet 42, a water supply valve 40 and a float 41, as is found on most gravity flushing and siphonic flushing toilets. The water supply valve 40 and float 41 act as a water level 50 governor as will be known by a person skilled in the art.

[0028] Inside the tank 10, there is a flush valve 80 and an overflow pipe 60, which are typical in most standard toilets. The overflow pipe 60 has a first opening 61 and a second opening 62.

[0029] When a user activates the flush valve 80 in the usual manner by pushing a flush button (not shown), the water flows out of the tank 10 into a toilet pan or bowl (not shown). When this occurs, the float 41 moves as the tank 10 empties its water contents into the toilet pan, which then causes the water supply valve 40 to move from a closed position to an open position. When the water supply valve 40 is in the open position, water from a water supply is allowed to flow into the tank 10 via the water supply inlet 42. When the water in the cistern 10 reaches a predetermined water level 50, the float 41 causes the water supply valve 40 to move back to the closed position, thereby shutting off the water entering the tank 10 from the water supply inlet 42.

[0030] Toilets will typically have an overflow pipe 60. The function of the overflow pipe 60 is to expel water from the tank 10 into the toilet pan, when the tank 10 overfills. For example, if the water supply valve 40 fails to function as intended and water continues to enter the tank 10 via the water supply inlet 42, then the water level will continue to rise above the predetermined water level 50. Rather than spilling over the top of the tank 10, the water will flow into the overflow pipe 60 at the second opening 62, and into the toilet pan out of the first opening 61. [0031] As is disclosed in the Applicant’s international PCT patent application Nos PCT/AU2007/000003 (WO 2007/079/079524) and PCT/AU2018/000006 (WO 2018/140998), the cistern 1 may be equipped with a fan assembly 30. Figure 1 shows the fan assembly 30 having an inlet 31 and an outlet 32. Turning to Figures 3 and 4, the fan assembly 30 has a fan body 34. Inside the fan body 34, there is also has a one-way valve 33 and a fan (not numbered). Reverting to Figure 1, the objective of the fan assembly 30 is to draw gas from the toilet pan via the overflow pipe 60. The gas drawn from the overflow pipe 60 is expelled via the outlet 32 of the fan assembly 30. If further information relating to the operation of the valve 33 and the fan of the fan assembly is required, refer to the Applicant’s aforementioned disclosures.

[0032] Also shown in Figures 1 and 2 is chamber member 20. Chamber member 20 has a body 25, which in turn has an inlet 21, an outlet 22 and at least one aperture 23. In the preferred embodiment shown in the figures, the chamber body 25 has four apertures 23. Although Figure 2 shows the chamber body 25 with four apertures 23, it is envisaged that the chamber 20 could be made with fewer larger apertures or a greater number of smaller apertures. However, to improve function of the chamber 20, it is preferable to have more smaller apertures, rather than one large aperture. In other embodiments, the at least one aperture 23 may be a slim an elongate slot. Figures 3 and 4 show that the outlet 22 of chamber 20 is sealingly engaged with the inlet 31 of the fan assembly. The outlet 22 of the chamber 20 is press-fit into the inlet 31 of the fan assembly 30 to provide a seal. In an alternative embodiment (not shown) it is envisaged that the chamber 20 may be integrally formed with the inlet 31 of the fan assembly 30. The purpose of the at least one aperture 23 is to allow airflow into a cavity 24 of the chamber 20, from the tank 10. In other words, the purpose of the at least one aperture 23 is to prevent a “bell siphon” effect when the fan assembly 30 is engaged by the user. If no pressure relief aperture(s) is present, then the water in the tank 10 is drawn above the predetermined water level 50 and into the overflow pipe 60 which is undesirable. Alternatively, if the at least one aperture 23 is too large, then too much air is drawn from inside the tank 10 (rather than the overflow pipe and pan as intended) which reduces the “odourless” performance of the cistern 1.

[0033] When the tank 10 is filled to the predetermined water level 50, the overflow pipe 60 is sealingly engaged with the chamber member 20. The inlet 21 of the chamber 20 is submerged in the water stored in the tank 10, when the tank 10 is filled to the predetermined water level 50, thereby creating the seal. The overflow pipe 60 has second opening 62 which opens into cavity 24 of the chamber 20, thereby being in fluid communication. It follows that the overflow pipe 60 is in fluid communication with the tank 10 and the toilet pan (not numbered). By submerging the inlet 21 of the chamber 20, a seal is created with the second opening 62 of the overflow pipe 60. This seal is created using the water in the tank 10, meaning that an installer is not required to create a seal between the fan assembly inlet 31 and the over flow pipe second opening 62. Essentially, the seal between the fan assembly inlet 31 and the over flow pipe second opening 62 is created automatically when the tank 10 is filled to the predetermined water level 50.

[0034] The at least one pressure relief aperture 23 ensures that the predetermined water level 50 remains at the predetermined level and is not sucked above the predetermined water level 50 and into the overflow pipe 60, when the fan is activated by a user. The at least one aperture 23 is sized to allow a first airflow into the chamber and the second opening 62 of the overflow pipe 60 is sized to allow a second airflow into the chamber 20. The first airflow is less than the second airflow. 23, which prevents a “bell siphon” from occurring, when the user flushes the toilet and the fan assembly 30 is engaged.

[0035] As shown in the figures, the chamber inlet 21 and outlet 22 are substantially annular. The size of the chamber inlet 21 is greater than that of the chamber outlet 22. In an alternative embodiment, the chamber inlet 21 and outlet 22 may be substantially rectangular to assist with fitting inside different cistern tanks.

[0036] Use of the invention will now be described.

[0037] When a user activates the fan in the fan assembly 30, gas or generally undesired odours are drawn from the toilet pan into the overflow pipe 60 via the first opening 61. The gas is drawn through the overflow pipe 60 and into the chamber 20 via inlet 21, due to the seal created with the water in the filled tank 10. The gas then passes through the open valve 33 of the fan assembly 30 and is expelled to waste via the fan body outlet 32. When the user actuates the flush button and the water drains from the tank 10, the seal of the chamber 20 and the overflow pipe outlet 62 will be broken as the water escapes from the tank 10, or the water drops below the predetermined water level 50. However, at this point the majority of the gas will have already been expelled to waste.

[0038] Advantages of the present invention will now be described. [0039] A person installing the fan assembly 30 does not need to worry about sealing all gaps in the cistern tank. The seal between the fan assembly 30 and the overflow pipe 60 is created automatically by the water stored in the tank 10. It follows that installation of the fan assembly 30 simpler and less time consuming.

[0040] The at least one apertures 23 are minimal enough to maximise volumetric air flow through the overflow pipe 60 from the pan, but large enough to prevent the fan from drawing the water stored in the tank 10 above the predetermined water level 50 and into the overflow pipe 60, thus eliminating a bell siphon effect.