In many commercial and industrial establishments mains pressure flush valves are used on the toilets. To operate efficiently these valves must be set up to pass about 1.2 litres of flush water per second into the bowl. For normal supply pressures between about 30 kpa to 300 kpa known prior art valves are generally able to operate at this flow rate without difficulty. However in some installations such as for example high rise buildings where the water supply is taken from a roof cistern the pressure head of water on the lower floors can reach 1100 kpa. At this pressure existing flush valves become very noisy and are unable to limit the flow rate to anything near the required value.

It is an object of this invention to ameliorate the aforementioned disadvantages and accordingly there is disclosed a flow regulator device for a mains pressure valve such as a toilet flush valve or the like, said device comprising a housing having an outer ring member and an inner cone member disposed centrally of said ring member, one or more fluid flow channels defined between the outer periphery of said cone member and an inner wall of said ring member and a elastic flow restriction member adjacent the inner wall of said ring member whereby in use a pressure differential on said elastic restriction member caused by fluid flow through said channels deforms said restriction member inwardly to at least partially obstruct said channels, the volume of flow through said regulator being thereby kept substantially constant through a range of flow pressures and said outer ring member being disposed within an annular bush adapted for sealing location within the inlet conduit to said mains pressure valve.

Preferably said cone member is formed with radial fins around the periphery thereof so that at least part of said flow channels are defined between said fins.

It is also preferred that said elastic restriction member comprise a commercially available O-ring.

The currently preferred form of this invention will now be described with reference to the attached representations in which: Figure 1 is a perspective view from the inlet side of a flow regulator according to this concept, Figure 2 is a perspective view of the regulator of figure 1 from the outlet side, Figure 3 shows an example of a toilet flush valve in partial section to which the flow regulator of figure 1 may be fitted, Figure 4 is a cross-sectioal view along the lines A-A of figure 1 with the elastic restriction member undeformed at zero flow pressure, and Figure 5 is a cross-sectional view similar to figure 4 but with the elastic restriction member deformed inwardly under pressure flow conditions.

Referring first to figures 1 and 2 there is shown a regulator designated generally as 1 with a central cone 2 and a surrounding ring housing 3. The cone 2 has radial fins 4 and is held at its position within the ring 3 by flanges 5 as best shown in figure 2. An elastic restriction member 6 which in this case is a commercially available O-ring sits inside a niche in the ring housing 3. Defined between the cone 2 and the inner periphery of the ring housing 3 as well as between adjacent fins 4 are fluid flow channels 7. Fluid such as water can thus pass through the regulator with the volume flow being related to the cross-sectional area of these channels 7 and the applied pressure. The above assembly sits within an annular bush 8 and is secured in place from the outlet side by a spring clip 9. A peripheral seal 10 which may also be an O-ring sits in a recess around the outside of the bush.

In use the device may be placed within the control cock tail pipe 11 of a conventional mains pressure toilet flush valve 13 as shown by arrow "A" in figure 3. The inlet side of the regulator 1 faces upstream toward the control cock 14.

The diameter of the bush 8 is chosen so as to be a close tolerance sliding fit within the pipe 11 so that the peripheral seal 10 engages the wall thereof. Preferably one side of the bush also abuts the end 15 of the adjoining valve inlet pipe so as to support the regulator against the force of the incoming water flow.

As mentioned earlier the velocity of flow through the channels 7 causes a corresponding pressure differential between the inner and outer surfaces to act on the O-ring 6. This deforms the ring from the substantially circular configuration shown in figure 4 to the inwardly compressed shape of figure 5 where it abuts the ends of the fins 4 and partially obstructs the channels 7 to thereby reduce the cross-sectional flow area. The result of this progressive restriction is that the volume flow rate of water allowed to pass through the flush valve 13 can be maintained at or close to the optimum valve of 1.2 litres per second over a vastly increased range of mains supply pressures including up to 1100 kpa found in high rise buildings. This results in a lower noise level and an extended life for the flush valve.

It will thus be appreciated that this invention at least in the form of the embodiment described provides a novel and improved flow regulator device for mains pressure flush valves. Clearly however the example disclosed is only the currently preferred form of this invention and a wide variety of modifications may be made which would be apparent to a person skilled in the art. For example the shape and configuration of the regulator housing and bush may be changed according to application or design preference. Also while the regulator has been described in relation to toilet flush valves the device may be adapted for other applications such as for example water supply valves in air conditioning plants.