DRAIN INSERT Field

The present invention relates to drains such as are found in shower recesses, laundries, bathroom floors and the like, and particularly to traps that prevent ingress of material such as odours, bacteria, soap suds or vermin into the room from the drain.

Background to the Invention Drains are smelly and contain potentially harmful

bacteria. Ingress of foul smelling odours, bacteria, soap suds or vermin into the room being drained, typically a shower recess or bathroom, laundry or kitchen floor, is a known problem with several existing partial solutions.

It is known to provide a drain insert beneath the grate of the drain that contains a water trap, such that the water is funnelled into a reservoir with an upper level above the outlet of the funnel , whereby the water proceeds to drain only by overflowing of the reservoir. As a result, after a draining event has occurred, the reservoir is full and acts as a trap to prevent odours , bacteria or other material entering the room from the drain via the funnel outlet, since the outlet remains submerged. International patent application publication number WO 99/27199 is an example of such devices . The water trap concept has the disadvantage that the reservoir may gradually evaporate and the funnel outlet may become exposed, particularly presenting a problem for infrequently used drains .

It is also known to provide a drain insert with an

elastomeric valve element composed of opposing flexible flaps that are closed together at an outlet end in the absence of water flow, but open under the weight of draining water to allow draining to occur. Australian Patent application AU 20088243269 and US patent 6,795,987 are examples of such devices. While the elastomeric trap solves the problem of evaporation, it has the problem that closure of the elastomeric seal may not be complete and may become more unreliable with wear.

There is therefore a need to provide an improved drain insert.

Summary of the Invention According to a broad aspect of the invention there is provided a drain insert for insertion in a drain beneath a drain grate to prevent ingress of material, comprising

an elastomeric valve disposed between the drain grate and the drain that is closed in the absence of draining liquid and opens due to its presence; and

a reservoir that fills and overflows with the draining liquid passing through a drain path outlet that is below an upper level of the reservoir. In one embodiment, the reservoir is downstream of the elastomeric valve. In this embodiment, the drain path outlet may be an outlet of the elastomeric valve and the reservoir may be a cup disposed beneath and around the outlet, integrally formed with a grate engaging element that also houses the elastomeric valve. Further, the elastomeric valve may be disposed beneath the grate to collect the draining liquid passing through the grate, and proximate the outlet may be shaped into two opposing panels connected at edges that flex apart between the edges in response to the pressure to open the outlet.

In another embodiment, the reservoir is upstream of the elastomeric valve. In this embodiment, the drain path outlet may be an outlet of a liquid guide that collects the draining liquid passing through the grate and guides it therethrough. Further, the elastomeric valve may comprise a molded elastomer surrounding the liquid guide outlet and the reservoir may be a base of the molded elastomer with the upper level thereof defined by lower extrema of a plurality of vertically disposed valve elements .

Brief Description of Drawings

Figure la to Id depict a drain insert according to a first embodiment of the invention;

Figure 2a to 2d depict a drain insert according to a second embodiment of the invention.

Detailed Description of embodiments

Embodiments of the current invention will now be

described. Referring first to Figure la, the drain insert is provided by grate engaging element 11, connected by integrally molded connecting element 15 to reservoir 13, and

elastomeric valve 16. Grate 10 has a screw thread 12 adapted to engage with a mating screw thread on grate engaging element 11, made of rigid plastic. Elastomeric valve 16 is composed of molded elastomeric material such as PTE, silicone or urethane.

Referring now to Figure lb, the drain insert is shown in vertical cross-section engaged with grate 10 and installed inside drain pipe 23. Elastomeric valve 16 contains an annular projection 17 adapted to fit snugly inside a corresponding groove in grate engaging element 11. Elastomeric valve 16 has a generally tapering shape changing gradually from circular cross-section at the top to two opposing panels 18a and 18b joined at edges 19 at the bottom (one edge only shown) .

In use, waste liquid 20 drains into grate 10 and is channelled through elastomeric valve 16, which is

initially closed. The pressure of liquid accumulating in the valve forces opposing panels 18a and 18b to flex apart and allow liquid to drain through the outlet end 24 into reservoir 3. The liquid level fills reservoir 3 to the upper level 21 and begins to overflow as shown by the flow arrow. Outlet end 24 of the elastomeric valve defines a drain path outlet that is below the upper level 21 of the reservoir 3.

Referring now to Figure lc, the state of the drain insert after a draining event is shown, with outlet end 24 closed due to lack of water pressure acting against the molded shape of elastomeric valve 16. Reservoir 3 is full at the upper level 21, submerging outlet end 24. As can be seen with the dashed flow arrows , material such as vapours 25 is prevented from seeping back through drain grate 10 by the liquid level 21.

Referring now to Figure Id, the same arrangement is seen in the event of evaporation of the water in the reservoir to expose outlet end 24. As can be seen with the dashed flow arrows, vapours 25 are still prevented from seeping back through drain grate 10 by the closed outlet end 24 of the elastomeric valve. Thus the invention provides greater protection against potentially harmful vapours by the provision of redundancy from the dual mode of action, in this case with the reservoir 3 downstream of the

elastomeric valve 16.

Referring now to Figures 2a to 2e, a second embodiment of the invention is shown wherein the reservoir is upstream of the elastomeric valve. Figure 2a shows a configuration adapted to an 80 mm trap. Grate engaging element 31 constructed from rigid plastic and is circular in cross- section and funnel-shaped, terminating in an outlet end 37 that defines a drain path outlet. Annular rim

projection 40 is adapted to receive elastomeric valve 32 which comprises a molded elastomer surrounding the liquid guide outlet 37 and a base 34 of the molded elastomer forms a reservoir with the upper level thereof defined by lower extrema of a plurality of vertically disposed valve elements 33a, 33b. Valve elements 33a and 33b are each molded with narrow opposing panels that provide an

effective seal when closed together in the absence of liquid pressure.

Figure 2b shows a similar variant adapted to a 100 mm trap.

Figure 2c shows the drain insert of Figure 2b with the elastomeric valve 32 attached to grate engaging element 31 and the vertically disposed valve elements 33a to 33d parted in the open position such as occurs due to liquid pressure during a draining event. Figure 2d shows the insert in drain pipe 50 with relative heights of liquid guide outlet 37 and vertically disposed valve element 33c with lower extremum 51c so as to define a reservoir. As in the first aspect of the invention, both a liquid trap and an elastomeric valve closure provides redundant, dual modes of action.

As will be apparent for persons skilled in the art, additional protection from bacterial ingress and odour may be provided by impregnating any or all of the drain insert components with silver, preferably in the form of

nanoparticles , that exert an antibacterial action . It will also be apparent that the insert can be adapted to be fixed either to the grate as described herein or alternatively to be otherwise fixed in place beneath the grate .

Persons skilled in the art will also appreciate that many variations may be made to the invention without departing from the scope of the invention.

In the claims which follow and in the preceding

description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.