GB2389040A

GB2389040A - Overflow preventer

Info

Publication number: GB2389040A
Application number: GB0212420A
Authority: GB
Inventors: Roger Sale; Matthew Hurley
Original assignee: DIY DIRECT EXPRESS Ltd
Current assignee: DIY DIRECT EXPRESS Ltd
Priority date: 2002-05-29
Filing date: 2002-05-29
Publication date: 2003-12-03
Also published as: GB0212420D0

Abstract

An overflow preventer comprising a plug body (1) receivable into, and fully removable from, a drain hole, the plug body comprising an upper portion (2) and a lower portion (3), the upper portion (2) having a substantially circular configuration with a plurality of openings (4) on its upper surface and the lower portion (3) having a generally annular configuration surrounding an aperture (5) and a sealing washer (6) associated with the plug body (1) and movable between a first position in which the openings (4) are closed and a second position in which the openings (4) are open to allow fluid to drain through the aperture (5) , the sealing washer (6) being resiliently biased to the first position, when the hydrostatic pressure acting on it in use is less than a predetermined value, by a pressure sensitive Belleville washer (7), the sealing washer (6) having an upper surface against which hydrostatic pressure bears in use, the said surface being adapted for sealing abutment against cooperating portions of the upper surface of the plug body (1) in said closed position.

Description

( 2389040

OVERFLOW PREVENTER

The present invention relates to an overflow preventer, and more particularly to an overflow preventer which comprises a plug body receivable into, and fully removable Rom, a drain 5 hole of for example a bath, basin, sink, cistern or other installation in which water or other liquids are collected and which include a drain hole.

Overflow preventers are known, which comprise a plug body receivable into, and fully removable from, a drain hole of for example a bath or basin. Generally speaking, these 10 devices include a valve which is normally closed, but which can open when a certain pre determined depth of water is exceeded. The device can therefore function as a plug under normal circumstances, and as a water outlet when the water approaches an overflow condition. 15 As is well known, a user may start to fill a bath or basin from for example 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 water. If, however, an overflow preventer is used in place of a conventional plug, the danger is avoided. In the initial rest position of the overflow preventer, the valve is biased closed to form a seal. When the bath or basin is filled with 20 water, the hydrostatic pressure on the valve increases. As filling proceeds the hydrostatic pressure on the valve gradually increases until a point is reached whereby 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. 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 25 prevent unnecessary loss of water through the drain hole.

International (PCT) Patent Application No. WO-A-95/18896 (Stewart et al), 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 30 apertures and is arranged to open when the hydrostatic pressure above the apertures exceeds a pre-deterrnined amount.

Australian Patent No. AU-B-700030 (Smartplug Pty Ltd), 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.

s I lnited Kingdom Patent No. 2 338 184, describes another generally similar overflow preventer. The prior art overflow preventers generally super from the disadvantages of a relatively

10 restricted water outlet area. 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.

15 A further disadvantage of the prior art overflow preventers arises due to the use of

conventional compression springs to bias the valve in the closed position. This results in a valve which may open to varying degrees depending on the hydrostatic pressure. Since it is the aim of such overflow preventers to facilitate the release of water from a vessel into which they are fitted only when the hydrostatic pressure exerted upon the overflow preventer 20 exceeds a certain predetermined value it would be preferable to have a valve which was either "open" or "closed" The nature of conventional compression springs means that as the hydrostatic pressure increases the valve will be allowed to open gradually until it is in the fully open position. Thus such overflow preventers are fairly imprecise and may allow leakage below the intended threshold value.

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.

30 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, the plug body

( comprising an upper portion and a lower portion, the upper portion having a substantially circular configuration with a plurality of openings on its upper surface and the lower portion having a generally annular configuration surrounding an aperture; and 5 b) a sealing washer associated with the plug body and movable between a first position in which the openings are closed and a second position in which the openings are open to allow fluid to drain through the aperture, the sealing washer being resiliently biased to the first position, when the hydrostatic pressure acting on it in use is less than a predetermined value, by a pressure sensitive Belleville washer, the sealing washer having an upper surface 10 against which hydrostatic pressure bears in use, the said surface being adapted for sealing abutment against cooperating portions of the upper surface of the plug body in said closed position. The sealing washer acts in cooperation with the plug body to define a valve.

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, in the general manner of doing so, without the need for adjustment or tampering with the drain hole and associated installations. The plug body preferably has an external 20 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 preferred that the overflow preventer further comprises a return mechanism arranged to bear against the underside of the Belleville washer when in the second position and biased to 25 return said Belleville washer and the sealing washer to the first position when the hydrostatic pressure acting on the surface of the sealing washer in use drops below the predetermined value. The said predetermined value of the hydrostatic pressure, below which the sealing washer is 30 biased to the closed position, can be selected during the manufacturing stage from within a range of values, by the selection of a Belleville washer of a sufficient strength which will bias the sealing washer to the extent appropriate to the desired value of the hydrostatic pressure. It

( would therefore be possible to alter the hydrostatic pressure at which the overflow preventer operates by utilising Be11eville washers of different strengths. In the embodiment of the overflow preventer where the plug body is formed from two releasably coupled portions such that access to the internal components is available this alteration could be performed by the 5 consumer who may purchase the overflow preventer with a number of different Belleville washers. In order to operate efficiently water must be able to flow freely through aperture when the sealing washer is in the second position. For this reason it is preferred that the openings on 10 the upper surface of the plug body represent at least 60% of the cross sectional area of the aperture. The sealing washer is preferably fixed to the Belleville washer such that the Belleville washer will pull the sealing washer down and away from the openings on the upper surface of the 15 plug body when it moves from the first to the second position. It is therefore preferred that the underside of the sealing washer is provided with a dip which is capable of encapsulating at least a portion of the projections of the Belleville washer.

The sealing washer may be bonded to the Belleville washer in any suitable manner as will be 20 easily understood by a person skilled in the art for example waterproof adhesive bonding.

It is preferred that the upper and lower portions of the plug body are releasably coupled together. This enables access to the internal components of the overflow preventer and I facilitates easier cleaning and replacement of the sealing washer and/or Belleville washer.

The plug body and sealing washer are each suitably formed of plastics materials, which may be the same of different as between the two parts. The sealing washer may, for example, be of a softer material than the plug body, preferably a durable and flexible plastics material. It is more preferable that the sealing washer is made of a rubberized polymer.

30; It is preferred that the upper surface of the plug body is convex in shape. 1

The overflow preventer may suitably be used in the drain hole of a conventional household pop-up waste system. When this is the case it is preferred that means are provided whereby the overflow preventer may be lifted out of, and returned into, the drain hole. Such means may take the form of a lever system or a cable operated system. This feature allows the user 5 to release water from the bath or basin without the need to fully remove the overflow preventer from the system.

The plug body preferably has an attachment point on its upper surface to which a conventional plug chain may be attached.

For a better understanding of the invention, and to show more clearly how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: 15 Figure I is an illustration of a perspective view of one embodiment of an overflow preventer according to the present invention; and Figure 2 is an illustration of an exploded perspective view of the overflow preventer of Fig. 1. I 20 The general dimensions of the overflow preventer correspond to the 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 25 removable from, a drain hole of for example a bath, basin, sink, cistern or other installation in which water or other liquids are collected and include a drain hole. The plug body I comprises an upper portion 2 and a lower portion 3 which are releasably coupled together.

The upper portion 2 has a generally circular configuration with a plurality of openings 4 on its upper surface. The upper surface of the upper portion 2 has a generally convex 30 configuration such that in use the outer edge may lie substantially flush with the surface of the bath, basin or other installation to which it is fitted. The upper surface of the plug body is I provided with an attachment point 11 to which a conventional plug chain may be attached.

The lower portion 3 has a generally annular configuration surrounding a central aperture S. I the exterior surface being tapered for fitting into the drain hole.

The overflow preventer further includes a sealing washer 6 having a generally annular 5 configuration. The sealing washer 6 is enclosed in the internal space defined by the upper portion 2 and the lower portion 3. In use the sealing washer 6 is resiliently biased into watertight sealing abutment against the openings 4 of the upper portion 2 of the plug body 1.

The sealing washer 6 is resiliently biased into watertight sealing abutment by means of a I O Belleville washer 7, or disc spring, arranged to bear against the underside of the sealing washer 6. The sealing washer 6 is bonded to the Belleville washer 7.

The Belleville washer 7 has a plurality of projections 8 extending inwards from an annular body 9.

The nature of the Belleville washer 7 means that in use it takes up one of two positions, a first position in which the projections 8 extend above the plane of the annular body 9 and a second position in which the projections 8 extend below the plane of the annular body 9. The Belleville washer 7 is arranged such that at rest i.e. with no hydrostatic pressure on the plug 20 body, it is in the first position such that the sealing washer 6 is biased into watertight sealing abutment with the openings 4 on the upper portion 2 of the plug body 1. When the hydrostatic pressure acting on the upper surface of the upper portion 2 exceeds the predetermined value the Belleville washer 7 "flips" to its second position. The sealing washer 6, which is bonded to the Belleville washer 7, is pulled away from the openings 4 and water is able to pass 25 through the overflow preventer.

Different strengths of Belleville washer 7 may be selected in order to provide an overflow preventer which operates at different hydrostatic pressures.

30 A circular return leaf spring 10 is located below the Belleville washer 7, between said Belleville washer 7 and the lower portion 3 of the plug body 1. When the Belleville washer 7 is in its second position the circular return leaf spring is arranged to bear against the

underside of it. The circular return leaf spring 10 is biased such that when the hydrostatic pressure acting on the upper surface of the upper portion 2 of the plug body 1 drops back below the predetermined value the circular return leaf spring 10 forces the Belleville washer 7 to return to its first position thereby returning the sealing washer 6 to a watertight sealing 5 abutment with the openings 4 on the upper portion.

Consequently, the overflow preventer works as a "trigger", allowing water to escape instantaneously when the predetermined hydrostatic pressure is exceeded and preventing a gradual loss of water below this level. This also prevents water escaping with body 10 movement that creates "waving" of the water and thus fluctuations in the head of water.

The mechanism operates passively and continuously, requiring no user intervention, opening and closing until the water supply is stopped.

Claims

1. An overflow preventer comprising: 5 a) a plug body receivable into, and fully removable from, a drain hole, the plug body comprising an upper portion and a lower portion, the upper portion having a substantially circular configuration with a plurality of openings on its upper surface and the lower portion having a generally annular configuration surrounding an aperture; and 10 b) a sealing washer associated with the plug body and movable between a first position in which the openings are closed and a second position in which the openings are open to allow fluid to drain through the aperture, the sealing washer being resiliently biased to the first position, when the hydrostatic pressure acting on it in use is less than a predetermined value, by a pressure sensitive Belleville washer, the sealing washer having an upper surface 15 against which hydrostatic pressure bears in use, the said surface being adapted for sealing abutment against cooperating portions of the upper surface of the plug body in said closed position.

2. An overflow preventer according to claim I, further comprising a return mechanism 20 arranged to bear against the underside of the Belleville washer when in the second position and biased to return the Belleville washer and the sealing washer to the first position when the hydrostatic pressure acting on the surface of the sealing washer in use drops below a predetermined value.

25

3. An overflow preventer according to claim 2, wherein the return mechanism comprises a circular return leaf spring.

4. An overflow preventer according to any preceding claim, wherein the underside of the sealing washer has a lip which accommodates the projections of the Belleville washer.

5. An overflow preventer according to any preceding claim, wherein the sealing washer is bonded to the Belleville washer.

t (

6. An overflow preventer according to any preceding claim, wherein the upper and lower portions of the plug body are releasably coupled together.

7. An overflow preventer according to any preceding claim, wherein the upper surface of 5 the plug body is convex in shape.

8. An overflow preventer according to any preceding claim, wherein the sealing washer is formed from a durable, flexible material.

10

9. An overflow preventer according to any preceding claim, wherein the sealing washer is formed from a rubberised polymer.

10. An overflow preventer according to any preceding claim, wherein the drain hole into which the overflow preventer is fitted forms part of a pop-up waste system.

11. An overflow preventer according to claim 10, wherein the pop-up waste system comprises means for moving the overflow preventer between a first position in which it is engaged with the drain hole and a second position in which is lifted clear of said drain hole.

20

12. An overflow preventer according to any preceding claim, wherein the upper surface of the plug body has an attachment point to which a conventional plug chain may be attached.

13. An overflow preventer substantially as hereinbefore described with reference to the . accompanying drawings.