HYDROSTATIC DRAIN PLUG

Abstract: A hydrostatic drain plug/outlet assembly comprises a hollow body (1) with an inlet port and an outlet port for connection to a fluid conduit. A slidable valve member (6) is movable between a locked open position and a locked closed position via an intermediate position at which the valve member (6) is urged into sealing engagement with a sealing member (3) by a spring (21) which supports a hydrostatic pressure of predetermined magnitude beyond which excess hydrostatic pressure is relieved by the valve member to prevent liquid overflow in a vessel. The valve member is moved between the locked open position and the locked closed position by rotation of valve member (6).

Description: HYDROSTATIC DRAIN PLUG This invention is concerned with improved drain or waste plugs for liquid containing vessels. The invention is particularly although not exclusively concerned with drain or waste plugs (hereinafter referred to generally as drain plugs) for use in association with waste outlets of hand basins, sinks, baths, spa baths, floor drains and the like in domestic and commercial buildings, laboratories and the like. The simplest forms of drain plug in general use comprise a rigid or flexible frusto-σonical plug adapted to engage in a frusto-conical neck of complementary shape in the neck of a waste outlet or alternatively a plug with a flexible flange adapted to engage an annular rim of a waste outlet. While generally effective for their purpose in providing a means to retain a body of liquid within a vessel these plugs suffer a number of disadvantages. Both types of plugs referred to above form a seal under the pressure of a head of water in the vessel and as the depth of water increases, the effort required to remove the plug increases greatly. For children or aged or infirm persons this can be most inconvenient and in some cases quite dangerous. Furthermore, if attention is distracted whils filling a bath, hand basin or like vessels, the vesse may be allowed to overflow with disastrous consequences S UBST I TUTE SHEET to carpets, furnishings and building structures both in domestic dwellings and multi-storey dwellings such as hotels, apartments etc. A significant disadvantage associated with plugs of the above type is that generally they are not captive and thus are easily lost, misplaced or, in the case of hotels and the like, stolen thereby necessitating costly frequent replacements. Although it is possible to make a drain plug captive by attachment of a cord or chain this is not always convenient and can be unsightly and difficult to clean. There have been many attempts to overcome the disadvantages associated with prior art drain plugs. Exemplary of these are Australian Patent applications 12445/52 and 36335/89, Australian Patent No. 213319, International Patent Application No. PCT/GB85/00345 (WO86/01100) and Australian Patent Application No. 66157/81. Patent Application No. 12445/52 concerns a waste outlet having a rotatable plate with apertures selectively alignable with apertures in the body of the outlet. The plate is rotatable to open or close the waste outlet. This device is difficult and inconvenient to operate, suffers from poor liquid sealing capacity and an exposed spring mechanism provides a lint trap leading ultimately to poor drainage and blockage. Patent Application No. 36335/89 describes a device similar to that of Patent Application No. S UBSTϊTUTE SHHCT 12445/52 but comprises a removable plug assembly which is easily lost or stolen. Australian Patent No. 213319 describes a captive plug/waste outlet combination wherein sealing engagement of the plug is achieved by rotating the plug on a threaded shaft to raise or lower the plug relative to the mouth of the outlet. This device suffers from poor drainage, entrapment of lint and, in the open position, protrudes above the surface of the outlet -nereby causing the potential for injury in a bath or the like. Patent Application No. PCT/GB85/00345 describes a waste outlet comprising a cover plate attached to one end of a shaft and a plug attached at the other end of the shaft. The plug is urged into sealing engagement with an outlet aperture against a spring biassing means by pushing downwardly on the cover plate and rotating through 90° by means of a bayonet coupling. This particular device is considered to be particularly prone to blockages due to entrapment of lint in both upper and lower spring mechanisms and such blockages would require a relatively difficult dismantling to clear the blockage. Each of the above types of plug/outlet combination are concerned with a plug which is subjected to hydrostatic pressure which enhances the liquid seal and thus increases the difficulty of disengaging the plug under a head of water. S UB S TITUTE SHEET Australian Patent Application No. 66157/81 describes an hydraulically actuated plug which seals against the hydrostatic pressure of a head of water. Apart from requiring an extremely expensive installation to permit selective application of mains water pressure to actuate the plug, the system is prone to water leakages in the pressure actuation system, blockages and poor sealing in the presence of foreign matter. Apart from Patent Application No. 36335/89 all of the aforementioned prior art waste plug/outlet combinations are subject to blockage by lint entrapment and require either removal of the waste pipe or complete dismantling of the plug/outlet combination for cleaning purposes. It is an aim of the present invention to overcome or alleviate the problems of prior art waste plug/outlet combinations and to provide a novel waste plug/outlet with additional advantages. According to the invention there is provided a waste plug/outlet apparatus for liquid retaining vessels, said apparatus including:- a hollow body portion having an inlet port and an outlet port, said outlet port being adapted for connection to a liquid conduit; a sealing means associated with said inlet port; a valve member movable between an open position spaced from said sealing means and a closed S UBSTITUTE SHEET position wherein said valve member sealingly engages against said sealing member; and, resilient biassing means to urge said valve member towards a closed position. Preferably said apparatus includes locking means to selectively lock said valve member in an open position. If required said apparatus may additionally or alternatively include locking means to selectively lock said valve member in a closed position. The sealing means may comprise any suitable means which, in association with said valve member, forms a liquid tight seal to prevent ingress of liquid into said inlet port. Suitably the sealing means is releasably attachable to said body portion to enable insertion to or withdrawal from the interior of said body portion of said valve member. Preferably saiu s li means comprises a sealing surface which diverges inwardly of said body portion. Suitably said sealing surface comprises a frusto-conical surface adapted to engage a complementary surface on said valve member. Preferably said biassing means comprises a compression spring operative between said movable valve member and valve support member associated with said body portion. S UBST I TUTE SHEET If required said biassing means may be adjustable to selectively vary the biassing force which urges said valve member towards a closed position. Suitably a cover means is associated with said biassing means to prevent, in use, contact between said biassing means and foreign matter entering said inlet port. The valve means suitably comprises a rotatable member having a circular head portion with a frusto- conical sealing surface and a central valve shaft rotatably mounted in said valve support member. Preferably said locking means comprises one or more projections extending perpendicularly to said valve shaft. The locking means suitably includes one or more slotted recesses associated with said valve support member to receive a respective projection to selectively retain said valve member in an open or closed position. The locking means may alternatively or additionally comprise one or more ramped surfaces associated with said valve support member to engage said one or more projections to guide said valve member into a locked open and/or a locked closed position upon rotation of said valve member. Preferably grip means is provided on a normally upper surface of said valve member to facilitate rotation thereof. Suitably said valve member is selectively S UBST I TUTE SHEET movable between a locked open position and a locked closed position via an intermediate unlocked position wherein said valve member is urged into sealing engagement with said sealing means by biassing force of predetermined magnitude. If required said biassing means may comprise a compressible fluid or an incompressible fluid associated with a pressure accumulation means. In order that the invention may be more readily understood, reference is now made to preferred embodiments of the invention illustrated in the accompanying drawings in which:- FIG 1 is a cross sectional view of a drain plug/waste outlet apparatus in the closed position FIG 2 shows the apparatus of FIG 1 in an open position FIG 3 shows the apparatus of FIGS 1 and 2 in an exploded perspective view FIG 4 shows a cross sectional view of an alternative embodiment of the invention FIG 5 shows a cross sectional view of an actuating means for the embodiment of FIG 4. Referring to FIGS 1-3, the drain plug/waste outlet comprises a body 1 having an externally threaded portion 2 to facilitate connection to a waste conduit (not shown) . Removably located in the upper opening or mouth of body 1 is an annular sealing member 3 which engages an internally threaded portion 4 in the mouth of S UBSTITUTE SHEET body 1. About the inner periphery of sealing member 3 is a frusto-conical sealing face 5 which diverges inwardly of body 1. Located within the hollow interior of body 1 is a valve member 6 slidably located in a valve support member 7. Valve support member 7 comprises a central portion 8 with an aperture 9 in which the valve member 6 is able to slide in a reciprocatory fashion. Extending radially from central portion 8 are spaced legs 10 which locate in recesses 11 formed on the inner wall of body 1. Valve member 6 comprises a circular cap 12 with a recess 13 in its upper surface. Within recess 13 is a finger grip portion 14 to facilitate rotation of valve member 6. About the periphery of cap 12 is located resilient seal 15 having a frusto-conical sealing surface 16 complementary to sealing surface 5 on sealing member 3. Depending from the lower side of cap 12 is a cylindrical shaft 17 which slidably locates in aperture 9 in valve support member 7. Also depending from the lower side of cap 12 is a circular wall 18 which in conjunction with hollow cylindrical shroud 19, forms a substantially sealed enclosure 20 housing a compression coil spring 21. Shroud 19 had a central aperture 22 through which shaft 17 is able to slide. A cylindrical pin 23 is inserted through an aperture in shaft 17 via opposed apertures 24 in shroud 19. S UBSTITUTE SHEET Located within shroud 19 and between pin 23 and the central portion 8 of valve support member 7 is an annular boss 25 with opposed "bayonet" slots 26 (shown in FIG 3) . FIG 1 shows the drain plug/waste outlet apparatus in a closed position whilst FIG 2 shows the apparatus in an open position. The operation of the apparatus according to the invention will now be described with reference to FIGS 1-3. The drain plug/waste outlet illustrated in FIGS 1-3 is readily fitted to sinks, hand basins, baths, showers, spa baths and like in a conventional manner. As shown in FIG 3, cap 12 is rotable between an "open" position through an intermediate "fill" position to a "closed" position. In the closed position shown in FIG 1, pin 23 rests upon the upper surface 26 of boss 25 and urges the resilient sea.. 15 into sealing engagement w th s l face 5 of sealing member 3 to prevent egress of water or the like through the waste outlet body 1. By rotating the cap 12 to the intermediate "fill" position, pin 23 is aligned with the upright portion of slots 26 whereby the valve member 6 may be pushed downwardly against the restoring force of spring 21. By selecting a spring 21 having a predetermined restoring force sufficient to support a given head of fluid pressure, the apparatus provides a very convenient S UBSTITUTE SHEET overflow prevention means for liquid container such as laundry tubs, hand basins, baths etc. When the liquid depth reaches a predetermined "safe" level, the pressure of the head of liquid above valve member 6 begins to exceed the restoring force of spring 21 and thus allows excess fluid to escape via the hollow interior of body 1. The apparatus according to the invention may be provided with a plurality of "standard" springs 21, each having a restoring force equivalent to a predetermined liquid depth in, say, a hand basin, a laundry tub and a bath. Alternatively spring compression means (not shown) in the form of removable spacer or a threaded collar on shaft 17 may be provided to selectively vary the head of liquid able to be supported by the apparatus in the "fill" position. To empty the liquid container to which the apparatus is fitted, cap 12 is pushed downwardly against the restoring force of spring 21 and then rotated to —i.i.a._}—t_ J_ιι u-x**; laterally extending portion of slots 26 in boss 25 thereby retaining the valve member 6 in an open position. While it will be readily apparent to a skilled addressee that the apparatus according to the invention is readily assembled and disassembled for manufacture, installation and maintenance purposes, there are other significant advantages. The configuration of the plug/outlet assembly S UBSTITUTE SHEET permits a more rapid evacuation of liquid due to lack of restrictions in the flow path and also due to the ready formation of a "whirlpool" effect at the mouth of the outlet. Furthermore, the shrouding of internal components which otherwise entrap lint, hair and other foreign matter reduces costly maintenance due to blockages and wear on movable components. In the event that maintenance is required the entire valve assembly is accessible and removable by removing sealing member 3 without the necessity for disconnecting the waste conduit attached to the apparatus. FIG 4 illustrates further embodiments of the invention. When the drain plug/waste outlet is to be used for floor drainage for, say, a shower or a parking lot where due to various circumstances a backflow of liquid can occur, an optional surge float 30 may be attached to the lower end of the shaft 31 attached to valve member 32. The surge float 30 urges valve member 32 into sealing engagement with sealing member 33 as the water level in the waste conduit 34 rises. If required, the volume of float 30 may be chosen to operate against a predetermined head of water to control ingress of liquid and to prevent further flooding of a floor surface. FIGS 4 and 5 also illustrate yet another embodiment of the invention in the form of a remote opening or closing device. In FIG 4 the valve support S UBSTITUTE SHEET member 34 has an integrally formed boss 35 in the form of a cylindrical body which εlidingly supports the shaft 36 of valve member 32. Resilient "0" ring seals 37, 38 form fluid tight seals respectively between the shaft 36 and inner wall of boss 35 on the one hand and the outer wall of boss 35 and shroud 39 depending from valve member 32 on the other hand. Within the wall of boss 35 is a fluid conduit 40 which is in fluid communication with a conduit 41 via an aperture 42 in the lower portion of body 43. When a source of pressurised fluid is supplied via conduit 41 valve member 32 is driven upwardly to seal against sealing member 33. By using a compressible fluid such as air, the valve member 32 may be driven into sealing engagement with sealing member with a predetermined force which is able to be overcome by an excess head of liquid above valve 32. Alternatively an incompressible fluid such as water, oil etc may be employed in conjunction with a diaphragm pressure accumulator or the like to provide a similar sealing force of predetermined magnitude. FIG 5 shows a convenient form of remote control of the apparatus of FIG 4. The pressurising device comprises a piston 40 and a cylinder 41 with a non return valve 42 which may be fitted behind a wall cladding material 43 otherwise recessed into a wall structure. Piston 40 comprises a large pushing cap 44 and a return spring 45. Cylinder S UBSTITUTE SHEET 41 communicates with a chamber 46 via non return valve 42 and chamber 42 is adapted to connect to conduit 41. Connected to chamber 46 is a needle and jet assembly 47 to selectively allow pressurised air to be bled from chamber 46 and conduit 41. The needle and jet assembly 47 is biassed into sealing engagement by a spring 48 the tension of which spring may be adjusted by rotation of the shaft 49 of the needle and jet assembly. The drain plug/waste outlet apparatus of FIG 4 may be closed by a single push of cap 44 to close the valve member 32 with a predetermined hydrostatic relief pressure determined by the biassing force of spring 48 in the needle/jet assembly 47. Valve member 32 may be opened simply by withdrawing shaft 49 against the biassing force of spring 48. To assist in more rapid opening of valve member 32, the float 30 shown in FIG 4 may be replaced with a solid mass. As no access is required to the top surface of valve member 32 to open or close the apparatus, an aperture grate may be incorporated in the sealing member 33 if required. The various embodiments of the apparatus according to the present invention are suitable for all domestic and commercial residential properties as well as nursing homes, hospitals and the like. The apparatus also has application in public facilities, floor drainage and industrial applications. It will be readily apparent to a skilled S UBSTITUTE SHEET addressee that many modifications and variations may be made to the invention without departing from the spirit and scope thereof. SUBSTITUTE SHEET

Claims: CLAIMS 1. A waste plug/outlet apparatus for liquid retaining vessels, said apparatus including:- a hollow body portion having an inlet port and an outlet port, said outlet port being adapted for connection to a liquid conduit; a sealing means associated with said inlet port, a valve member movable between an open position spaced from said sealing means and a closed position wherein said valve member sealingly engages against said sealing member; and, resilient biassing means to urge said valve member towards a closed position. 2. An apparatus as claimed in claim 1 including locking means to selectively lock said valve member in an open position. 3. An apparatus as claimed in claim 1 or claim 2 including locking means to selectively lock said valve member in a closed position. 4. An apparatus is claimed in any preceding claim wherein said biassing means is adjustable to selectively vary the biassing force which urges said valve member towards a closed position. 5. An apparatus as claimed in any preceding claim wherein a cover means is associated with said biassing means to prevent, in use, contact between said biassing means and foreign matter entering said inlet port. S UBSTITUTE SHEET 6. An apparatus as claimed in any preceding claim wherein said valve means comprises a rotatable member having a frusto-conical sealing surface. 7. An apparatus as claimed in any preceding claim wherein said locking means comprises one or more projections extending perpendicularly to a shaft associated with said valve member. 8. An apparatus as claimed in claim 7 wherein said locking means comprises one or more slotted recesses associated with a valve support member to receive a respective projection on said shaft to selectively retain said valve member in an open or closed position. 9. An apparatus as claimed in any preceding claim wherein said locking means comprises one or more ramped surfaces which engage with a corresponding surface during rotation of said valve member to guide said valve member into an open position or a closed position. 1G. An apparatus as claimed in any preceding claim wherein said biassing means comprises a compressible fluid or an incompressible fluid associated with a pressure accumulation means. S UBSTITUTE SHEET

Inventors: LEWIS MITCHELL LEE, LEWIS, MITCHELL, LEE
Applicants: JATTKE UDO, LEWIS MITCHELL LEE, JATTKE, UDO, LEWIS, MITCHELL, LEE
Application year: 1991
Main classification: F16K17
IPC codes: A47K1, E03C1, F16K17