WO2002002881A1

WO2002002881A1 - Overflow preventer

Info

Publication number: WO2002002881A1
Application number: PCT/GB2001/002590
Authority: WO
Inventors: Robert Malcolm Stewart
Original assignee: Bulk Hardware Ltd
Current assignee: Bulk Hardware Ltd
Priority date: 2000-06-29
Filing date: 2001-06-14
Publication date: 2002-01-10
Anticipated expiration: 2002-12-29
Also published as: AU2001264093A1

Abstract

The overflow preventer generally has the form and function of a conventional plug for a drain hole (2) of a bath, sink or the like (3), the plug body (1) having a generally annular configuration surrounding a circular central aperture (4). A valve (5) is resiliently biassed from below into watertight sealing abutment with the plug body (1) by means of a helical compression spring (8). When the hydrostatic pressure acting on the valve (5) in use is less than a predetermined value (corresponding to a shallow depth of water in the bath, sink or the like (3)) the valve (5) is in its closed position as shown. When the hydrostatic pressure acting on the valve (5) in use exceeds the predetermined value (corresponding to a depth of water in the bath, sink or the link (3) which is approaching an overflow risk) the spring (8) is compressed and the valve (5) moves to an open position to allow water to drain through the overflow preventer. The plug body (1) and the valve (5) are arranged such that an upwardly directed surface (6) of the valve (5), against which surface the hydrostatic pressure bears in use, extends substantially unschielded across the entire aperture (4) of the plug body (1).

Description

OVERFLOW PREVENTER

The present invention relates to an overflow preventer, and more particularly to an overflow preventer for baths, sinks and the like, which comprises a plug body receivable into, and fully removable from, a drain hole of the bath, sink or the like.

The term "bath, sink or the like" used herein includes all installations in which water or other liquids are collected and which include a drain hole. In addition to baths and sinks, basins and cisterns may also be mentioned without limitation.

Overflow preventers are known, which comprise a plug body receivable into, and fully removable from, a drain hole of a bath, sink or the like. Generally speaking, these devices include a valve which is normally closed, but which can open when a certain pre-determined depth of water is exceeded in the bath, sink or the like. The device can therefore function as a plug under normal circumstances, and as a water outlet when the water level in the bath, sink or the like approaches the overflow condition.

As is well known, a user may start to fill a bath, sink or the like from a tap (faucet), and may then be distracted or called away while the filling continues. In such a situation, there exists a real danger of overflow of possible very hot water. If, however, an overflow preventor is used in place of a conventional plug, the danger is avoided. In the initial rest position of the overflow preventer, the valve is biassed closed to form a seal. When the bath, sink or the like is filled with water, the hydrostatic pressure on the valve increases. If filling is continued, the pressure on the valve will overcome the bias and urge the valve to open. A flow passage will then be opened and water will drain away.

When the supply of water to the bath, sink or the like stops, water will continue to drain away until the hydrostatic pressure of water no longer overcomes the bias. The bias will then act again to urge the valve closed, to prevent unnecessary loss of water through the drain hole.

International (PCT) Patent Application No. WO-A-95/18896 (Stewart et al), the disclosure of which is incorporated herein by reference, describes such an overflow preventer in which the plug body is provided with apertures between an outer and an inner region of the plug body, and a resiliently biased valve is disposed below the apertures and is arranged to open when the hydrostatic pressure above the apertures exceeds a pre-determined amount.

Australian Patent No. AU-B-700030 (Smartplug Pty Ltd), the disclosure of which is incorporated herein by reference, describes a generally similar overflow preventer (Figures 1 to 4), and also (Figures 5 to 8) a variant in which a manually actuable override mechanism is additionally present, and is provided with a locking device to lock the valve in the open condition.

The prior art overflow preventers generally suffer from the disadvantages of a relatively restricted water outlet area, as well as no, or only an inconvenient, manually actuable override mechanism. Such an override mechanism could be very useful, to enable a user to drain the bath, sink or the like quickly and conveniently and without having to extract the device from the drain hole. Moreover, the construction of the prior art devices is generally somewhat elaborate, involving a large number of cooperating parts, leading to increased manufacturing costs, to undesirable bulk and weight of the complete devices, and to a likelihood of internal fungal growth as a result of water being trapped in the mechanisms.

It is an object of the present invention to go at least some way towards overcoming the disadvantages present in the prior art devices, or at least to provide an acceptable alternative to the prior art devices.

According to the present invention, there is provided an overflow preventer comprising:

(a) a plug body receivable into, and fully removable from, a drain hole of a bath, sink or the like, the plug body having a generally annular configuration surrounding an aperture, and

(b) a valve associated with the plug body and movable between a first position in which the valve closes the aperture and a second position in which the aperture is open to allow water to drain through the aperture, the valve being resiliently biased to the first position while the hydrostatic pressure acting on the valve in use is less than a predetermined value, the valve including an upwardly directed valve surface against which valve surface the hydrostatic pressure bears in use, the said surface being adapted for sealing abutment against cooperating portions of the plug body in the said closed position;

wherein the plug body and the valve are arranged such that the valve surface extends substantially unshielded across the entire aperture of the plug body.

The teπn "extends substantially unshielded" used herein refers to the requirement that the upwardly directed valve surface which occludes the aperture is presented to the entire water column above the entire aperture surrounded and defined by the annulus of the plug body with no, or negligible, shielding by overlying fixed parts of the overflow preventer (such as, for example, the "spider web" frame arrays which overlie the valve mechanisms in the prior art referred to above), whereby the valve can easily be opened by a user's finger or toe to override the biassing of the valve to the closed position. In numerical terms, it is preferred that the area of the valve surface which in use directly supports a full column of water is equal to at least about 90%, particularly 100%, of the area within the annulus of the plug body.

The term "receivable into, and fully removable from, a drain hole" used herein refers to the requirement that the overflow preventer can be easily inserted into, and removed from, a drain hole by hand, in the general manner of a conventional plug, without the need for adjustment or tampering with the drain hole and associated installations. The plug body preferably has an external surface which is dimensioned and configured for fitting into the drain hole in the general manner of a conventional plug, and in particular has a tapering curved external surface.

It is most preferred that the plug body has a single central aperture, which is preferably circular in shape.

The said predetermined value of the hydrostatic pressure, below which the valve is biased to the closed position, can be selected during the manufacturing stage from within a range of values, by resiliently biassing the valve to the extent appropriate to the desired value of the hydrostatic pressure, below which the valve is biased to the closed position.

The valve is preferably disposed substantially below the aperture of the plug body. The overflow preventer may be provided with means for locking the valve in the open or the closed position. The locking means, if present, may be of conventional construction, and in particular may be releasable.

According to the present invention, the plug body and the valve are arranged such that the valve surface extends substantially unshielded across the entire aperture of the plug body. This surface is thereby accessible for the user to conveniently override the valve. The valve surface may have any desired surface configuration. It is most preferred that the configuration of the upper surface is so shaped that, in use at a hydrostatic pressure lower than the predetermined automatic opening value, the valve can be conveniently opened by a depression action of the finger, heel or toe of a user of the bath, sink or the like, to override the resilient biassing of the valve to the closed position. The configuration of the valve surface may conveniently be convex, particularly domed.

The valve surface is adapted for watertight sealing abutment against cooperating portions of the plug body in the closed position. Most preferably, the inner periphery of the aperture of the plug body and the outer periphery of the valve surface are adapted so that the two meet in sealing abutment in the closed position of the valve. A convex, e.g. domed, configuration of the valve surface, at least at the outer periphery thereof, provides a useful peripheral guide surface which can slide over the cooperating portion of the plug body and assists in bringing the two parts into the desired abutment on closure of the valve.

The plug body and the valve are each suitably formed of plastics material, which may be the same or different as between the two parts. The valve may, for example, be of a harder material than the plug body. The parts are preferably formed by moulding and are each preferably unitary. The resilient biassmg of the valve is suitably accomplished by means of a spring arranged to bear against the valve, preferably from below. The spring may conveniently be a helical spring (such as a compression spring or a tension spring) or a flat spring (such as a leaf spring or a hybrid spring such as a Belville spring). A helical compression spring is preferred. By selecting, during the manufacturing stage, a spring which provides the desired degree of restoring force, the desired value of the hydrostatic pressure below which the valve is biased to the closed position can be selected for the overflow preventer.

The valve and associated spring may conveniently be held in place, generally within the annulus of the plug body, by means of a retainer part, which may engage the plug body in any suitable manner (e.g. by push or snap fitting) to retain the valve and the spring between the plug body and the retainer. In this way, the present invention makes available an extremely simple construction consisting essentially of four basic parts, namely the plug body, the valve, the spring and the retainer.

The spring is preferably disposed along a central longitudinal axis of the overflow preventer, between - at the lower end of the spring - a cross member of the retainer which traverses the aperture of the plug body below the valve and - at the upper end of the spring - the valve. To assist smooth opening and closing the valve, a guide member, e.g. a guide rod, preferably proj ects from the underside of the valve and cooperates with the spring to maintain a longitudinal path of action on the valve.

The configuration of the valve surface may suitably be chosen to minimise the total top to bottom depth of the overflow preventer. In particular, by using a convex, e.g. domed, valve surface, the overall depth of the overflow preventer can be less than would be necessary if the same spring length were to be used with a valve having a flat valve surface. This reduction in the dimension of the overall device has aesthetic advantages, and enables the overflow preventer to sit deeper in the drain hole, thereby improving its attractiveness to the user.

According to one specifically preferred embodiment of the present invention, therefore, there is provided an overflow preventer consisting essentially of: (a) a plug body receivable into, and fully removable from, a drain hole of a bath, sink or the like, the plug body having a generally annular configuration surrounding an aperture;

(b) a valve associated with the plug body and movable between a first position in which the valve closes the aperture and a second position in which the aperture is open to allow water to drain through the aperture, the valve being preferably disposed below the aperture;

(c) a spring associated with the valve to resiliently bias the valve to the first position while the hydrostatic pressure acting on the valve in use is less than a predetermined value; and

(d) a retainer associated (and optionally integral) with the plug body to retain the valve and the spring between the plug body and the retainer;

wherein the valve includes an upwardly directed valve surface against which valve surface the hydrostatic pressure bears in use, the said surface being adapted for sealing abutment against cooperating portions of the plug body in the said closed position, and the plug body and the valve are arranged such that the valve surface extends substantially unshielded across the entire aperture of the plug body.

The present invention therefore makes available a simple overflow preventer, which (a) does not require any adjustments to be made to existing installations, (b) is easy to use, even for those with impaired manual dexterity, (c) avoids or reduces the risk of fungal growth caused by water lying in enclosed mechanisms, (d) avoids or reduces the risk of fouling by hair or other debris, (e) includes a simple override mechanism easily actuable by a user's finger, heel or toe, or by a stick or similar implement, (f) creates a substantially improved outflow efficiency, in comparison with known devices of comparable size, (g) is easy to clean, and (h) fits into a drain hole in generally the same way, and with generally the same external appearance, as a conventional plug. Moreover, it has been found that the device of the present invention, with the valve in the open position, can provide an improved hydrodynamic performance in terms of outflow drainage efficiency, in comparison with an unmodified drain hole. Without wishing to be bound by theory, it is believed that when water drains from a bath, sinlc or the like, it primarily runs down the interior wall of the waste pipe, as a result of surface tension and capillarity effects, and tends not to fall down the centre of the waste pipe under gravity alone. By using a valve having an upper surface configuration - particularly a convex, e.g. domed, configuration - which directs the water outflow radially outwards and downwards in a smoother way than would be achieved by a flat valve surface, the device of the present invention is found to assist the outflow performance through the drain hole.

For further illustration of the present invention, and to show how the same may be performed in practice, an embodiment will now be described, purely by way of example and without limitation, with reference to the accompanying drawings, wherein:

Figure 1 shows an overflow preventer in exploded perspective view;

Figure 2 shows a vertical cross sectional view of the overflow preventer of Figure 1, with the valve in the closed position; and

Figure 3 shows a vertical cross sectional view of the overflow preventer of Figure 1 , with the valve in the open position for outflow of water.

Referring to the drawings, in which like reference numerals denote like parts, there is shown an overflow preventer useful as a plug for a bath, sink or the like. The general shape and dimensions of the overflow preventer correspond to the shape and dimensions of a conventional plug, and the illustrated device is intended to be interchangeable with such a plug.

The illustrated overflow preventer comprises a plug body 1 receivable into, and fully removable from, a drain hole 2 of a bath, sink or the like 3. The plug body 1 has a generally annular configuration surrounding a circular central aperture 4, the exterior surface being tapered for fitting into the drain hole 2.

The overflow preventer further includes a valve 5 having a generally mushroom shape including a domed upper surface 6. The valve 5 is resiliently biassed into watertight sealing abutment (see Figure 2, which illustrates this closed position) against the inner periphery 7 of the annulus of the plug body 1 from below, by means of a helical compression spring 8 arranged to bear against the underside of the valve 5 from below. The resilience of the spring 8 is selected so that it will compress, to allow the valve 5 to open under the hydrostatic pressure (as shown in Figure 3 , which illustrates this open position), when the column of water above the valve exceeds a pre-determined depth.

The plug body 1 and the valve 5 are each formed of plastics material, which in the illustrated device are different materials as between the two parts. The valve 5 is of a harder material than the plug body 1. The parts are formed by moulding and are each unitary.

As shown particularly in Figures 2 and 3, the valve 5 and associated spring 8 are held in place, generally within the annulus of the plug body 1, by means of a ring-shaped retainer/locator 9, which is engaged with the plug body 1 by snap fitting, to retain the valve 5 and the spring 8 between the plug body 1 and the retainer/locator 9.

The spring 8 is disposed along the central longitudinal axis 10 of the overflow preventer, between - at the lower end of the spring - an upwardly directed end face of a cylindrical hub portion 11 of the retainer/locator 9, which is supported on a tripod-shaped cross- member 12 of the retainer/locator 9 which traverses the aperture 4 of the plug body 1 below the valve 5, and - at the upper end of the spring - the underside of the valve 5. To assist smooth opening and closing of the valve, a guide rod 13 projects from the underside of the valve and cooperates with the spring 8 to maintain a longitudinal path of action on the valve.

The valve 5 is thereby movable, against the restoring force of the spring 8, between the closed position (Figure 2), in which the valve 5 closes the aperture 4 in watertight manner, and the open position (Figure 3), in which the aperture 4 is open to allow water to drain through the aperture 4 (see Arrows A in Figure 3).

The plug body 1 and the valve 5 are arranged such that the domed valve surface 6 extends substantially unshielded across the entire aperture 4 of the plug body 1. This surface 6 is thereby accessible for the user to conveniently override the valve 5. In particular, if the overflow preventer is in use at a hydrostatic pressure lower than the predetermined automatic opening value, the valve 5 can be conveniently depressed by the finger, heel or toe of a user of the bath, sink or the like, to override the resilient biassing of the valve 5 to the closed position.

The function of the overflow preventer during the process of filling a bath, sink or the like will now be described briefly. As is well known, a user may start to fill a bath, sink or the like from a tap (faucet), and may then be distracted or called away while the filling continues. In such a situation, there exists a real danger of overflow of possible very hot water. In the initial rest position of the overflow preventer, the valve 5 is biassed against the plug body 1 to form a seal. When the bath, sink or the like is filled with water, the hydrostatic pressure on the valve 5 increases. If filling is continued, the pressure on the valve 5 will overcome the bias and urge the valve to move off the plug body 1. The valve 5 will then move to the position shown in Figure 3. A flow passage will then be opened and water will drain away (Arrows A). When the supply of water to the bath, sink or the like stops, water will continue to drain away until the hydrostatic pressure of water no longer overcomes the bias. The spring 8 will then act again to urge the valve 5 back to the seat on the plug body 1, and will thereby prevent unnecessary loss of water through the drain hole.

The foregoing broadly describes the present invention, without limitation. Variations and modifications as will be readily apparent to one of ordinary skill in this art are intended to be included in the scope of this application and subsequent patent(s). For example, those skilled in this art will have no difficulty in selecting an appropriate biassing force to provide any desired maximum depth of water before the overflow preventer opens.

Claims

1. An overflow preventer comprising:

2. An overflow preventer according to claim 1, wherein the plug body has a single central aperture.

3. An overflow preventer according to claim 1 or claim 2, wherein the aperture is circular in shape.

4. An overflow preventer according to any one of the preceding claims, wherein the valve is disposed substantially below the aperture.

5. An overflow preventer according to any one of the preceding claims, wherein the surface configuration of the valve surface is convex.

6. An overflow preventer according to claim 5, wherein the valve surface has a domed configuration.

7. An overflow preventer according to any one of the preceding claims, further including a spring arranged to bear against the valve for resiliently biassing the valve to the first position while the hydrostatic pressure acting on the valve in use is less than the predetermined value.

8. An overflow preventer according to claim 7, wherein the spring is arranged to bear against the valve from below.

9. An overflow preventer according to claim 6 or 7, wherein the spring is a helical compression spring.

10. An overflow preventer according to any one of claims 7 to 9, wherein the spring is disposed along a central longitudinal axis of the overflow preventer.

11. An overflow preventer consisting essentially of:

(a) a plug body receivable into, and fully removable from, a drain hole of a bath, sink or the like, the plug body having a generally annular configuration surrounding an aperture;

(b) a valve associated with the plug body and movable between a first position in which the valve closes the aperture and a second position in which the aperture is open to allow water to drain through the aperture;

(c) a spring associated with the valve to resiliently bias the valve to the first position while the hydrostatic pressure acting on the valve in use is less than a predetermined value; and (d) a retainer associated with the plug body to retain the valve and the spring between the plug body and the retainer;

12. An overflow preventer according to claim 11 , wherein the valve is disposed substantially below the aperture.

13. An overflow preventer according to claim 11 or 12, wherein the retainer engages the plug body to retain the valve and the spring between the plug body and the retainer.