GB2378648A

GB2378648A - A plug for preventing back-surge through a waste outlet

Info

Publication number: GB2378648A
Application number: GB0120212A
Authority: GB
Inventors: Ray Wolfenden
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-08-18
Filing date: 2001-08-18
Publication date: 2003-02-19
Anticipated expiration: 2021-08-18
Also published as: GB2378648B; GB0120212D0

Abstract

A plug for preventing back-surge through a waste outlet is provided. Several different embodiments are described but in the most straightforward the plug is provided with hooked legs 6 which engage with the radial ribs of the outlet grid in order to compress ring-seal 3 against the outlet.

Description

FLOODWATER/SEWAGE PROTECTION FOR BUILDINGS This invention relates to floodwater/sewage protection for buildings.

Global climatic change is increasing the amount of rainfall in many parts of the world. More importantly, it is increasing the intensity of rainfall, leading to more frequent flooding of those areas with an established flood risk, and to the flooding of new areas with little or no flooding history. Such effects are bringing abject misery to large numbers of people unable to defend their buildings against floodwater penetration, unable to sustain repeated clean-up and repair operations, and unable to secure insurance to mitigate their loss Drainage pipes provide an important secondary means of floodwater/sewage entry into buildings.

Large volumes of floodwater entering main sewers under roads and streets via gullys and manhole covers for example, result in serious overloading of the sewerage system. Consequent internal pressures within the system cause venting of the combined floodwater/sewage mixture via gullys and manhole covers for example in other parts of the system, and the backflow of sewer contents into buildings via connecting drainage pipes.

Backflow will always enter a building first through the lowest drainage outlet. For example, in a domestic building without cellars this would normally be the outlet to a ground floor bath or shower tray, progressing to the outlet of a toilet or bidet, then to a sink or basin etc gradually up the building as the internal pressure within the sewerage system rises. However, such venting and backflow can initially take the form of a high-pressure back-surge which occurs just before wholesale flooding of an area, and can therefore provide a warning of imminent inundation. Any method of preventing backflow into a building will need to counteract these pressures.

Backflow preventer valves installed In the underground sewer or sewer connecting pipe leading from a building have been available for some time, but are expensive to purchase, install and maintain, are prone to blockage without warning and are notoriously unreliable in the event they are required to operate. Furthermore, in sewerage applications which naturally involve the transport of semi-solids in addition to fluids in horizontal or near horizontal underground pipes, clogging of the valve aperture and closure means by trapped semi-solids and accumulated slime is inevitable, monitoring and access is difficult, and clearance is unpleasant.

For these reasons their use is restricted.

It is therefore a primary object of this invention to prevent the entry of floodwater and sewage into a building in above-ground drainage pipes during back-surge and during flood conditions, and for such prevention means to withstand the pressures arising within these pipes without distortion, dislocation or leakage for a protracted period of time at least as long as those conditions shall last.

It is another object to provide such prevention means which is inexpensive to manufacture and simple to install In both new-build and retrofit situations.

Another object is to provide such prevention means which is user-friendlyvisible, accessible, controllable, secure, dependable, quick and easy to operate using one hand, and light and compact to standby when not in use.

Another object is to provide such prevention means which IS robust and durable in construction, positive in location and seal, and needing no maintenance Another object is to provide alternative variations of such prevention means for application according to need, from the simples to the most technically sophisticated.

Another object is to ensure harmonisation of all components with relevant British Standards

According to the present invention there IS provided a floodwater/sewage protection means for buildings having a waterproof plug inserted into a preformed waste outlet of a sink, basin, bath, shower tray, bidet or other water appliance so as to form a waterproof seal between some or all of the touching surfaces of the plug and the outlet and be removably restrained in this position such that when subjected to the pressure of sewer contents backing up the drainage system during back-surge and during flood conditions existing for a protracted period of time, the plug is not displaced and the seal is not broken, thereby preventing floodwater sewage from entering buildings by this means.

In a first simplified embodiment of this invention a waterproof plug is inserted into a conventional preformed waste outlet of a sink, basin, bath, shower tray, bidet or the like, having an outlet grid with void areas so as to allow waste water to pass through and solid areas to prevent non-liquids from entering the drainage system.

The plug may be a push-fit into the outlet aperture, or In the case of a flush-fitting grid in a shower tray for example it may be installed direct into the grid. The plug, and indeed the outlet, may be of solid or compressible material and each have complementary sealing surfaces, and the plug may have a cap with shoulders extending onto the upward-facing return of the outlet.

The base of the plug has downwardly extending hooks which may be located in diametrically opposing positions and which pass through the void segments of the outlet grid when the plug is inserted into the outlet or direct into the grid, but which engage firmly under the solid areas or radial ribs of the outlet grid when the plug is pushed down and rotated slightly in the horizontal plane, both so as to maintain the sealing surfaces together in tight compression and prevent the plug being displaced under pressure from backing-up sewer contents.

In a second embodiment of this invention, the arrangement is the same as that of the first except the engagement hooks may be attached to the base of a disc which has at its centre, fixably attached to it and extending upwards, a short internally threaded tube. Around the tube is a doughnut-shaped ring-seal of compressible material which may be a push-fit onto the tube, and of slightly smaller external

diameter when uncompressed than the shaft of the outlet The cap has a bolt fixably attached at its centre which engages with the Internally threaded tube When rotated, the cap first locates the hooks under the radial ribs of the outlet grid, then squeezes the doughnut outwards against the shaft to make a continuous seal all round at the same time as pulling the hooks up tightly under the ribs so as to firmly secure the plug In place.

In a third embodiment, the arrangement is the same as that of the second except that a lock-ring may be conveniently inserted between the doughnut and the cap to first locate the hooks and to make for a more positive independent locking and unlocking movement, without the need for a high degree of frictional resistance at the threads In a fourth embodiment, the arrangement is the same as that of any of the previous embodiments except that the plug assembly may be configured to fit a waste outlet of the'pop-up'type now commonly in use in sinks, baths, basins and the like, and/or the waste outlet may be configured to fit the plug assembly.

In a fifth embodiment, an outlet grid is introduced into a waste outlet of the'pop-up' type able to accept either a dedicated plug in normal use or, during flood conditions, any of the special plugs described in the first, second, and third embodiments.

In all of these embodiments, the special plugs hereinbefore described may be replaced in normal use by conventional or simplified plugs not requiring high performance seals or to be restrained in position under pressure from backing-up sewer contents The performance of each of the embodiments and the ease of use may be improved by the specification of multiple ring-seals, engagement ramps for the hooks, and lock-out mechanisms later described in detail. In all the embodiments, the outlet may be a standard component commonly in use in sinks, basins, baths, shower trays, bidets and the like, and the plug specified so as to exactly fit, or the

plug and the outlet may both be special in the way they engage together so as to only fit each other.

All applications may be accommodated using three basic components rationalised from the embodiments described The five specific embodiments of this invention will now be described in detail by way of example, with reference to the accompanying drawings in which Figure 1 shows a cutaway cross-section of a waterproof plug according to a first embodiment of this invention inserted into a conventional preformed waste outlet of a water appliance with the hooks engaged under the radial ribs of the outlet grid and the seals compressed. (Note: waste outlet not shown cross-hatched for the sake of clarity) ; Figure 2 shows a view of the underside of a waterproof plug according to a first, second, or third embodiment of this invention and the underside of a grid of a conventional preformed waste outlet through which the hooks of the plug have passed and are engaged under the radial ribs of the outlet ; Figure 3 shows a cutaway cross-section of a waterproof plug according to a second embodiment of this invention inserted into a conventional preformed waste outlet of a water appliance with the hooks engaged under the radial ribs of the outlet grid prior to tightening of the seals. (Note : waste outlet not shown cross-hatched for the sake of clarity) ; Figure 4 shows a cutaway cross-section of a waterproof plug according to a third embodiment of this invention inserted into a conventional preformed waste outlet of a water appliance with the hooks engaged under the radial ribs of the outlet grid prior to tightening of the seals (Note. waste outlet not shown cross-hatched for the sake of clarity), Figure 5 shows a plan view of a waterproof plug according to a third embodiment of

this invention being also a typical plan view of the first and second embodiments, Figure 6 shows a view of the underside of a waterproof plug according to a third embodiment of this invention being also a typical underside view of the first and

second embodiments ; Figure 7 shows a detail of two typical kinds of'ridge and slot'locking-out mechanism the first with both contact surfaces ramped, and the second with only one surface ramped; Figure 8 shows a detail of two typical kinds of'hook and step'locking-out mechanism: the first with one contact surface ramped, the second without ramps ; Figure 9 shows a cutaway cross-section of a waterproof plug inserted into a preformed waste outlet of the'pop-up'type both according to a fourth embodiment of this invention with the hooks engaged under that part of the pivoted linkage within the throat of the outlet, and the seals compressed. Inset shows view of locking-out mechanism taken in either direction within the throat of the outlet along the longitudinal axis of the pivoted linkage. (Note: waste outlet not shown crosshatched for the sake of clarity) ; Figure 10 shows a view of the underside of the arrangement shown in Figure 9 ; Figure 11 shows a cutaway cross-section of a waterproof plug inserted into a preformed'pop-up'waste outlet both according to a fifth embodiment of this invention mutually engaged together so as to allow normal use of a water appliance, the plug being able to be replaced in anticipation of flood conditions by any of the plugs described in the first, second and third embodiments. Inset shows cross-section taken through the longitudinal axis of the radial rib looking in the direction of the arrow and showing one type of ramping arrangement. (Note: waste outlet not shown cross-hatched for the sake of clarity) ; Figure 12 shows a view of the underside of the arrangement shown in Figure 11

Referring to the drawings, in a first method of preventing floodwater and sewage from entering buildings via above-ground drainage pipes shown in Figures 1 and 2, a waterproof plug 1 having shoulders 2 with a ring-seal 3 fixably attached thereto, is inserted into a conventional preformed waste outlet 4 having an outlet grid 5 with void areas so as to allow waste water to pass through and solid areas to prevent non-liquids from entering the drainage system The sides of the plug touching the outlet, and the corresponding sides of the outlet may be vertical, or slightly inclined to the vertical, and both may be circular in plan view and be in touching relationship all round.

The ring-seal may be made from a flexible, compressible and resilient material such as rubber, synthetic rubber and/or plastics and, for additional security, the plug may be made from the same range of materials so as to be also sealably compressed in the outlet. Alternatively, the plug may be made from any durable, waterproof, non-compressible material but preferably metal or plastics, so as may be in tight touching relationship with the outlet, and the outlet may be made from the same range of materials so as in this case to be reliant on the ring-seal for security. Optionally, the plug and/or the outlet may have additional or alternative nng-seal gaskets fixably attached to their touching sides, with or without the ringseal in the shoulders. Any metal components would need to be of a non-rusting or corroding type, or be permanently coated or encapsulated to avoid such effects.

Hooked legs 6 extend down from the base of the plug just far enough to enable the horizontal feet 7 of the legs to engage under the radial ribs 8 of the outlet grid when, using one hand, the plug is pushed firmly into the outlet and rotated slightly in the direction of the feet so as to retain the ring-seal and the sides of the plug in compression against the corresponding and complementary sides of the outlet.

The plug may be withdrawn using one hand, by pushing down firmly on the shoulders of the plug and counter-rotating slightly, before lifting the plug clear.

The conventional preformed waste outlet having an outlet gnd with void areas so as to allow waste water to pass through and solid areas to prevent non-liquids from entering the drainage system, may be already installed on a sink, basin, bath,

shower tray, bidet or the like, and the plug may be configured to fit standard designs as hereinbefore described. Equally however, the plug may be configured to fit a dedicated outlet of the conventional'grid type'which would replace any outlet already installed, and the dedicated outlet may have external threads, dimensional and other criteria according to the relevant British Standards so as to ensure harmonisation and Interchangeability.

The feet are properly engaged under the radial ribs when the front of the downwardly-extending legs is in contact with the edge of the ribs, and the plug will rotate no more The feet are properly disengaged from the radial ribs when the back of the downwardly extending legs is in contact with the edge of the adjoining ribs, and the plug will counter-rotate no more.

The amount of extension of the feet from the legs, and the width of the legs, is such as to permit easy passage of the feet through the voids of the outlet grid during installation and withdrawal, whilst at the same time enabling maximum contact between the feet and the underside of the ribs so as to permit them to engage together in secure fashion and thereby resist dislocation under pressure from sewer contents. The legs, the feet, and the ribs may be conveniently made from, but not confined to, rectangular section being of width greater than thickness so as to maximise the area of surface contact between foot and rib when engaged together, but not so wide as to interfere with the passage of the feet through the grid, and not so thin as for the material to deflect unduly during the process of engagement or when pressure is exerted on the base of the plug by sewer contents.

The installation method involving pushing down and turning using one hand is such as to overcompress the compressible seals slightly to an extent limited by the shoulders or the nng-seal attached thereto, to enable the feet to engage under the ribs. Releasing the hand pressure when the feet are in position enables the feet to properly contact the underside of the ribs and for the seals to relax slightly and assume the compression required to prevent the permeation of floodwater/sewage under predetermined pressure. The amount of compression, and of overcompression, needs to be controlled through the careful selection of

compressible material to be used and through the specification of appropriate manufacturing tolerances.

The material for the legs and feet may be the same as that of the plug and be fabricated or moulded Integrally with It, or it may be metal and be fixably attached to the base of the plug by mechanical means, welding and/or bonding. A fixing plate 9, which may be circular and slightly less In diameter than the shaft of the outlet, may be used to fixably attach the legs thereto and the plate may in turn be fixably attached to the plug each using any of the methods previously described Any metal components would need to be of a non-rusting or corroding type, or be permanently coated or encapsulated to avoid such effects The security of the engagement between foot and rib and the ease of engagement, may be suitably improved by'ndge and slot'profiling of the contact surfaces and by ramping, both shown in Figure 7. In this arrangement, either surface or indeed both surfaces may be ramped so as to positively increase the compression of the seals and progressively increase the pressure between the contact surfaces as the plug is rotated to engage foot and rib. At the point where engagement is complete, a projecting ridge across the contact surface of either component snaps into a complementary slot on the other using the pressure existing between the surfaces, and so lock-out foot and rib in their operating position.

Ramp profiling may be applied to the foot, nb or linkage by moulding, casting or machining a complementary inclined face on the engagement surfaces of either, or both, components or by twisting or bending either, or both, components to the optimum operating angle.

Alternatively, as shown in Figure 8, the ridge may be hook-shaped and located along the leading edge of one component so as to hook over the trailing edge of the other to lock-out and complete the engagement. Equally, the ridge may be of any convenient shape and disposition and the complementary slot or hole similarly, and be located within or adjoining the contact surfaces. The'ridge and slot'and'hook and step'locking-out mechanisms may also be applied

Independently, without any ramps In a further variation shown in the Inset to Figure 9, the rib is circular in crosssection at the point of engagement with the foot, and the foot is profiled as shown In the inset-first to locate the rib in the position indicated dashed, and then to capture it in the position indicated cross-hatched by slight rotation of the plug To disengage these optional and alternative lock-out mechanisms, the process of counter-rotating the plug prior to withdrawal is the same as without them, except that proportionately greater rotational force is required so as to overcome the resistance of the mechanism. Preferably, the lock-out mechanism will be arranged to engage when the plug is rotated clockwise and to disengage when rotated anticlockwise, but the reverse would be equally effective In a second embodiment of this invention shown in Figure 3, the general and optional arrangements, methods, and materials are the same as that of the first except that the engagement hooks 6 may be attached to the base of a disc 9 which may be dished so as to be concave side up and slightly less in diameter than the internal diameter of the outlet 4. The disc may have at its centre, fixably attached to it and extending upwards, a short internally threaded tube 10. Around the tube is a doughnut-shaped ring-seal 11 of compressible material of similar Internal diameter to the external diameter of the tube so as might provide a push-fit onto the tube, and of slightly smaller external diameter when uncompressed than the shaft of the outlet 4. A cap 1 with shoulders 2 extending onto the upward-facing return 12 of the outlet has a bolt 13 at its centre, one end of the bolt held fixably within the cap and the other extends downwards so as to locate with the threaded tube attached to the disc.

With the bolt partially screwed into the tube by rotating the cap, and with the doughnut-shaped nng-seal sandwiched between the underside of the cap and the upperside of the disc, the plug assembly is placed into the outlet as in the first embodiment such that the hooks which may be diametrically opposed are passed through the void segments of the outlet grid and the plug assembly pushed down

and rotated slightly such that the hooks engage under the radial ribs of the grid as shown in Figure 2. The bolt is then screwed fully home into the tube by further rotating the cap such that the doughnut seal expands to forcibly contact the shaft of the outlet, a reliable seal is made against the penetration of floodwater/sewage into the building, and the plug assembly is securely held in place to withstand the pressure from sewer contents.

Additionally or alternatively, the cap may have a ring-seal 3 partially rebated into the shoulders. Optionally, where such ring-seal is provided in the cap, the doughnut ring-seal may be replaced by a solid cylindrical body fixably attached to the disc and assuming the same overall dimensions as the uncompressed doughnut, but allowing a small intervening space between the body and the cap such that with the hooks engaged under the radial ribs, rotation of the cap will compress the ring-seal located under the shoulders against the upward-facing return of the outlet, thereby preventing the penetration of sewer contents under pressure.

It should be noted that in the second embodiment, a significant frictional resistance is required between the threads of the bolt and those of the tube to ensure that when the cap is rotated slightly to engage, or disengage, the hooks relative to the radial ribs of the outlet grid, cap and hooks rotate at the same speed without causing the bolt to screw, or unscrew, thus preventing proper engagement or disengagement Once the hooks have engaged, the vertical legs of the hooks contact the edges of the respective radial ribs, preventing further rotation of the legs whilst allowing further rotation of the cap and bolt, thereby tightening the seals against their complementary sealing surfaces. Removal of the plug involves counter-rotation of the cap and consequent untightening of the seals up to the point where rotational slippage occurs between the touching sealing surfaces causing counter-rotation of the hooks up to the point where the vertical legs of the hooks contact the edges of the adjoining radial ribs, and the plug may be withdrawn.

Materials for the cap and the optional body are taken from the range set out for the plug and the outlet in the first embodiment hereinbefore described, and those for

the ring-seals from the range set out for the ring-seals also In the previous embodiment. Materials for the disc, the threaded tube, the bolt and the engagement hooks would be preferably metal or plastics either separately or together. Any metal components would need to be of a non-rusting or corroding type, or be permanently coated or encapsulated to avoid such effects In a third embodiment of this invention shown in Figures 4,5 and 6, the general and optional arrangements, methods, and materials are the same as that of the second with the exception that a lock-ring 14 may be conveniently inserted between the doughnut ring-seal 11 (or optional body) and the cap 1 to make for a more positive locking and unlocking movement without the need to control the degree of fnctional resistance at the threads.

The lock-ring may take the form of a disc of some thickness having a hole at its centre through which both bolt 13 and tube 10 pass, the tube having means on its external surface to locate with the disc so that turning the lock-nng clockwise or counter-clockwise will engage, or disengage, the hooks under the radial ribs of the outlet gnd, whilst at the same time allowing the tube to slide vertically within the hole when the bolt is screwed into or out of the tube by rotating the cap.

To facilitate this, the outside of the tube and the inside of the hole through which it passes may, when viewed in plan, both have splines or any irregular or regular shape other than circular. Alternatively, the tube may have a pin or pins 15 extending outwards from, and fixably attached to, that part of its external surface always in contact with the inside surface of the hole, and the inside surface of the hole may have a vertical slot or slots 16 in which the pin or pins slide, or any other convenient and robust method.

In addition to those optional aspects hereinbefore described in relation to the first and second embodiments of this invention, the third embodiment may have a partially-rebated ring-seal 17 inserted on the underside of the cap so as to prevent the further penetration of floodwater/sewage under pressure which has negotiated the threads between the bolt and the tube. The third embodiment may also have an

upstanding rim 18 around the circumference of the lock-ring, overlapping the cap so as to provide additional surface area with which to grip the edge of the lock-ring and ergonomic advantage to one-handed installation and withdrawal.

Fitting of the plug is performed in the same manner as in the second embodiment, except that it is the lock-ring which is rotated slightly to first positively engage the hooks prior to rotating the cap to tighten the seals, and the lock-ring counter-rotated slightly to finally positively disengage the hooks following counter-rotating the cap to untighten the seals Materials for the lock-ring are taken from the range set out for the plug and the cap in the first and second embodiments hereinbefore described, and those for the optional additional ring-seal from the range set out for the ring-seals also in the previous embodiments.

In a fourth embodiment of this invention, the waste outlet is of the'pop-up'type now found on many sinks, basins, baths, and other water appliances where a plunger (often forming part of the tap assembly) is used to operate a pivoted linkage which pushes the plug upwards so that it projects slightly above the outlet and allows waste water to drain from the appliance, or allows it to drop back so that it rests in the outlet by virtue of its own weight and such that the ring-seal around it is sufficient to seal the outlet and hold water In the appliance whilst in use. The plug may be lifted out of the outlet completely, as required.

A plug assembly having the form of any of the previous embodiments may be configured to fit a standard'pop-up'waste outlet such that with the plunger pushed down, the hooks engage under that part of the pivoted linkage within the throat of the outlet, as opposed to the radial ribs of the outlet grid In the previous embodiments. Alternatively and preferably however, the plug assembly may be adapted to fit a dedicated'pop-up'waste outlet shown in Figures 9 and 10 where that part of the pivoted linkage within the throat is arranged : (1) to be horizontal so as to firmly accept the installation of the plug assembly

when the plunger IS pushed fully down, (2) to have its'free'end move in a vertical slot within the throat and the slot having stop ends such that the linkage is unable to deflect upwards or sideways during or following installation, and; (3) to be of circular section, or rectangular section having width greater than thickness, so as to facilitate ease of engagement of the hooks and optimum security following engagement, as previously identified In this embodiment, the downward extension of the plug, optional body, or hooks may need to be greater than In previous embodiments in order to reach the pivoted linkage which is located below the level of a conventional outlet grid. The legs therefore, may need to be of greater thickness and/or have a stiffening rib or ribs along their length, and the joint between the legs and the disc (plug) and the legs and the feet stiffened by a fillet or gusset, to limit flex under rotational load. The absence of adjoining radial ribs as would be found in a conventional outlet grid provides ample space for these aspects.

The legs may also be joined together from some point above the level of engagement with the linkage, all the way up to the disc or plug, and such method of joining enjoy fixity with the disc or plug, so as to resist torsional stress and stiffen the whole downwardly-extending structure. Alternatively and preferably as shown in Figures 9 and 10, short legs with feet may be attached to, or cut out from, the bottom of a tube of similar external diameter to that of the disc, where the tube is fixably and concentrically attached to the underside of the disc or plug or integrally moulded or fabricated as a part thereof so as provide a method of engagement which is lightweight, durable, and of high structural integrity.

Figures 9 and 10 show a cylindrical plug inserted into a waste outlet of the'pop-up' type. The plug has a cap 1 with shoulders 2 into which a ring-seal 3 is partially rebated, and a body 19 with external threads onto which a lock-ring 20 having internal threads is fully screwed. The lock-ring also has a partially rebated ring-seal

21 on its surface in contact with the upward-facing return of the outlet 12. The bottom of the plug is hollowed out such that the lowermost extent takes the form of a short tube 22 of similar external diameter to the body of the plug and a wall thickness sufficient to sustain intended use Along the lower edge of the tube and in diametrically opposing positions are feet 7, an engagement channel 29, and a captive lock-out mechanism 23 having the profile shown in the inset to Figure 9 and first described relative to the first embodiment.

One end of the pivoted linkage within the throat of the outlet 4 is restrained in a conventional pivot mechanism 24 as may be found in normal use which allows the linkage to move through an angle of approximately 15-20 degrees in the vertical plane about the central axis of the pivot 25 when the plunger is moved fully up and down. The other'free'end of the linkage within the throat is restrained in a special vertical blind slot 26 not found in conventional equivalents, the slot having upper and lower stop-ends 27,28 so as to still allow the angular movement of the linkage in the vertical plane from a horizontal position when the plunger is pushed fully down, to an inclined position when the plunger is pulled fully up, but not to allow the linkage to move sideways or beyond the horizontal when subjected to the rotational and compressive forces involved in installation of the plug. More explicitly, during engagement of the feet the'free'end of the linkage will remain horizontal and in contact with the upper stop-end 27 of the slot and the side of the slot when viewed in elevation from within the outlet, and during rotation of the lockring the'free'end of the linkage will be forced against the upper stop-end 27 of the slot.

With the plunger held down, rotating the cap slightly will allow the engagement channel 29 to drop over that part of the circular pivoted linkage rod within the throat such that the rod adopts a position shown dashed in the inset. Pushing the cap down and rotating slightly will complete the engagement of the rod in its captive position, shown cross-hatched. In this position the ring-seal in the cap is in compression against the complementary sealing surface of the lock-ring, and the ring-seal in the lock-nng is in compression against the upward-facing return of the outlet. Rotating the lock-ring slightly will increase the compression of the primary

ring-seal against the upward-facing return of the outlet, further increasing the security of the arrangement against the permeation of sewer contents under pressure. Equally however, the same arrangement without the lock-nng but with more downwardly-extending shoulders to the cap, and the ring-seal in the cap in compression against the upward-facing return of the outlet, may be applied to achieve sufficient security using the ring-seal compression resulting from the ramped profile of the feet and the lock-out mechanism.

Removal of the plug follows the opposite of the operating sequence outlined above with appropriate counter-rotational force being applied to overcome the lock-out mechanism. Preferably, the lock-out mechanism will be arranged to engage when the plug is rotated clockwise and to disengage when rotated anti-clockwise, but the reverse would be equally effective.

The lower portion of the outlet having the'pop-up'facility has internal threads which enable It to engage with the upper portion or alternatively with other standard'grid-type'outlets in general use, and external threads identical to the upper portion which enable it to engage with a bottle trap or other drainage fittings in general use. In the UK, the specification for these threads and other dimensional criteria is set out in the relevant British Standards and, excepting the special and unique features providing the subject of this application, wherever possible special components may follow the appropriate Standard so as to achieve harmonisation and interchangeability This arrangement, with or without a lock-ring, may also be applied to a dedicated 'grid-type'outlet having circular ribs, or ribs of alternative profile and complementary feet in any of the applications previously described or shown in Figures 7 and 8 The fourth embodiment, like the third embodiment, may also have an upstanding rim around the circumference of the lock-ring, overlapping the cap so as to provide additional surface area with which to gnp the edge of the lock-ring.

Materials for the plunger and pivoted linkage may be metal, and for the tube, body, lock-ring and housing for the linkage metal or plastics or a combination of the two,

separately or together Materials for the ring-seals and other components may be the same as previously specified. Any metal components would need to be of a non-rusting or corroding type, or be permanently coated or encapsulated to avoid such effects.

In a fifth embodiment of this invention shown in Figures 11 and 12, a dedicated 'pop-up'outlet of the type described in the fourth embodiment may additionally have an outlet grid 5 in the same or similar position to that of the outlet grid in a conventional outlet. The outlet grid may have several radial ribs 8 in the same way as a conventional outlet, or it may have as few as two which may be diametrically aligned, and the ribs may be profiled to accommodate complementary feet in any of the applications previously described or shown in Figures 7 and 8 and inset to Figure 9.

At the centre of the grid is a hole vertically aligned so as to accept a rod 30 fixably attached to the centre of a plug 31 which may be in the form of a disc at its upper end, and a plain-headed bolt 32 with head which may have the same diameter as the rod is partially screwed into a concentrically threaded hole into its lower end.

The hole in the grid may have internal threads and a short length of tubing 33 having external threads may be screwed into it or otherwise fixably attached from the underside so as to stabilise the rod In a vertical position when the rod is inserted into the tube.

The disc may be slightly smaller in diameter than the top of the outlet 4, and of thickness sufficient to accommodate a circumferential groove with a ring-seal gasket 35 partially rebated into it, such that when the plunger is pulled up the disc and the gasket are sealably engaged with the inside circumference of the outlet so as to effectively prevent water escaping whilst the appliance is In use, and when the plunger is pushed down water may flood under the disc into the drain. The plug may have outwardly-extending shoulders 34 so as to closely oversail the upwardlyfacing return 12 of the outlet, and additionally or alternatively the shoulders may have a concentric groove with a ring-seal gasket partially rebated into it so as to sealably engage with such return when the plunger is pulled up. As can be seen

from the foregoing, the plug may be withdrawn completely from the outlet when and as required, and the adjustment available by screwing or unscrewing the bolt is sufficient to ensure correct engagement of the plug in the outlet This arrangement and methodology of the plug and outlet in normal use allows, in the same outlet, the installation and withdrawal of a separate and special plug having the arrangement and methodology of any of the first, second or third embodiments or optional aspects hereinbefore described and the ribs of the outlet grid may be profiled accordingly without Interference with the use of conventional plugs.

Materials for the plunger and pivoted linkage may be metal, and for the disc, rod, bolt, grid and tube metal or plastics or a combination of the two, separately or together. Materials for the ring-seals and other components may be the same as previously specified. Any metal components would need to be of a non-rusting or corroding type, or be permanently coated or encapsulated to avoid such effects.

It will now be appreciated that with three basic components, the full range of waste outlet applications can be fitted and so protected against backftow (1) a special and dedicated'pop-up'outlet of the type described in the fifth embodiment having an upper portion which may be unscrewed and used independently without the'pop-up'function where required, such upper portion being configured to accept a conventional plug in addition to the dedicated plug described and having external threads configured to accept waste fittings meeting the requirements of the relevant British Standard (s), (2) a dedicated plug of the type described in the fifth embodiment ; (3) a separate and special plug having the form of the first, second or third embodiments or optional aspects hereinbefore described, to be installed when flood conditions are anticipated.

In any part of the foregoing description and specification any reference to the radial ribs of an outlet grid should be taken to include the solid areas of any outlet gnd whether radial or otherwise In all of these embodiments, the special plugs hereinbefore described may be replaced In normal use by conventional or simplified plugs not requiring high performance seals or to be restrained in position under pressure from backing-up sewer contents.

Claims

CLAIMS (1) A floodwater/sewage protection means for buildings having a waterproof plug inserted into a preformed waste outlet of a sink, basin, bath, shower tray, bidet or other water appliance so as to form a waterproof seal between some or all of the touching surfaces of the plug and the outlet and be removably restrained In this position such that when subjected to the pressure of sewer contents backing up the drainage system during back-surge and during flood conditions existing for a protracted period of time, the plug is not displaced and the seal is not broken, thereby preventing floodwater/sewage from entenng buildings by this means (2) A floodwater/sewage protection means for buildings as claimed in Claim 1, having a waterproof plug inserted into a preformed waste outlet where the plug and/or the outlet may be of solid or compressible material and each have complementary sealing surfaces.

(3) A floodwater/sewage protection means for buildings as claimed in Claims 1 and 2, where the plug may have a cap with shoulders extending onto the upwardfacing return of the outlet so as to be In touching relationship, so as to limit the extent to which the plug may be inserted into the outlet, and so as to assist manipulation during installation and withdrawal (4) A floodwater/sewage protection means for buildings as claimed In Claims 1-3, where the surfaces of the plug and cap in contact with the outlet may have a ring-seal or seals fixably attached thereto and additionally or alternatively be partially rebated into the surface thereof.

(5) A floodwater/sewage protection means for buildings as claimed In Claims 1-3, where the surfaces of the outlet in contact with the plug and cap may have a ring-seal or seals fixably attached thereto and additionally or alternatively be partially rebated into the surface thereof

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(6) A floodwater/sewage protection means for buildings as claimed in Claims 1-5, where the base of the plug has hooks (each comprising a downwardlyextending leg together with an outwardly-extending foot) fixably attached thereto and which may be located in diametrically opposing positions but always so that the hooks pass through the void segments of the outlet grid when the plug is inserted into the outlet, and extend down just far enough to enable the horizontal feet on the end of the legs to engage firmly under the solid areas or radial ribs of the outlet grid when the plug IS pushed down and rotated slightly in the horizontal plane, both so as to maintain the complementary sealing surfaces together in tight compression and prevent the plug being displaced under pressure from backingup sewer contents.

(7) A floodwater/sewage protection means for buildings as claimed in Claims 1-6, where the waste outlet is of a conventional type and size already in use and the plug is configured to fit, or where the plug and the outlet may both be special in the way they engage together so as to only fit each other and replace those existing in any installation.

(8) A floodwater/sewage protection means for buildings as claimed in Claims 1-5 and 7, where hooks comprising a downwardly-extending leg together with an outwardly-extending foot, are fixably attached to the base of a disc which has fixably attached to its centre and extending upwards, a short internally threaded tube around which a doughnut ring-seal may be a push fit, and into the tube a bolt, having its uppermost end fixably attached to the centre of a cap, is screwed such that when the disc and doughnut are inserted into a waste outlet up to a point limited by the ring-seal or shoulders on the cap, the feet first engage under the solid areas or radial ribs of the outlet, then the doughnut is squeezed so as to forcibly and sealably contact the internal circumference of the outlet all round whilst at the same time tightening the hooks up under the solid areas or ribs so as to firmly secure the plug in place.

(9) A floodwater/sewage protection means for buildings as claimed in Claims 1- 5 and 7-8 in which, through the selection of materials and configuration of the

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threads, a significant frictional resistance is arranged to apply at the threads of the bolt and tube when engaged together to ensure that when the cap is rotated slightly to engage, or disengage, the hooks relative to the solid areas or radial ribs of the outlet grid, cap and hooks rotate at the same speed without causing the bolt to screw, or unscrew, thus preventing proper engagement or disengagement (10) A floodwater/sewage protection means for buildings as claimed in Claims 1-5 and 7-9, in which a lock-ring is conveniently Inserted between the doughnut ring-seal and the cap to make for a more positive locking and unlocking movement without the need to control the degree of frictional resistance at the threads, the lock ring taking the form of a disc of some thickness having a hole at its centre through which both bolt and tube pass, the tube having means on its external surface to locate with the disc so that turning the lock-ring clockwise or counterclockwise will engage, or disengage, the hooks under the solid areas or radial ribs of the outlet grid, whilst at the same time allowing the tube to slide vertically within the hole when the bolt is screwed into or out of the tube by rotating the cap- (11) A floodwater/sewage protection means for buildings as claimed in Claims 1-5 and 7-10, where the outside of the tube and the inside of the hole through which it passes may, when viewed in plan, both have splines or any irregular or regular shape other than circular.

(12) A floodwater/sewage protection means for buildings as claimed in Claims 1-5 and 7-11, in which the tube may have a pin or pins extending outwards from, and fixably attached to, that part of Its external surface always in contact with the inside surface of the hole, and the inside surface of the hole may have a vertical slot or slots In which the pin or pins slide, the slots having a closed upper and/or lower end.

(13) A floodwater/sewage protection means for buildings as claimed in Claims 1-5,7 and 10-12, which may have a partially-rebated ring-seal inserted on the underside of the cap so as to prevent the further penetration of floodwater/sewage under pressure which has negotiated the threads between the bolt and the tube.

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(14) A floodwater/sewage protection means for buildings as claimed in Claims 1-5,7 and 10-13, which may have an upstanding rim around the circumference of the lock-ring, overlapping the cap so as to provide additional surface area with which to gnp the edge of the lock-ring and ergonomic advantage to one-handed installation and withdrawal.

(15) A floodwater/sewage protection means for buildings as claimed in Claims 1-5 and 7-14, In which the doughnut nng-seal is replaced by a solid cylindrical body assuming the same overall dimensions as the uncompressed doughnut, but allowing a small intervening space between the body and the cap such that with the hooks engaged under the radial ribs, rotation of the cap will compress the ringseal located under the shoulders against the upward-facing return of the outlet, thereby preventing the penetration of sewer contents under pressure.

(16) A floodwater/sewage protection means for buildings as claimed in any of the preceding claims, in which the plug assembly having the form of any of the previous embodiments may be configured to fit a standard'pop-up'waste outlet of the type now found on many sinks, basins, baths, and other water appliances such that with the plunger pushed down, the hooks engage under that part of the pivoted linkage within the throat of the outlet, as opposed to the solid areas or radial ribs of the outlet grid in the previous embodiments (17) A floodwater/sewage protection means for buildings as claimed in Claims 1-15, in which the plug assembly may be configured to fit a special and dedicated 'pop-up'waste outlet where that part of the pivoted linkage within the throat is arranged: (1) to be horizontal so as to firmly accept the installation of the plug assembly when the plunger is pushed fully down; (2) to have its free end move in a vertical blind slot within the throat and the slot having stop ends such that the linkage is unable to deflect upwards or sideways during or following installation, and; (3) to be of circular or rectangular section having width greater than thickness so as to facilitate ease of engagement of the hooks and optimum security following engagement.

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(18) A floodwater/sewage protection means for buildings as claimed in any of the preceding claims, in which the legs have a stiffening rib or nbs along their length, and the joint between the legs and the disc (or plug), and the legs and the feet, is stiffened by a fillet or gusset, to limit flex under torsional load (19) A floodwater/sewage protection means for buildings as claimed in any of the preceding claims, in which the legs may be joined together from some point above the level of engagement with the ribs or linkage, all the way up to the disc (or plug), and such method of joining enjoy fixity with the disc (or plug), so as to resist torsional stress and stiffen the whole downwardly-extending structure (20) A floodwater/sewage protection means for buildings as claimed in Claims 1-17, in which short legs with feet may be attached to, or cut out from, the bottom of a tube of similar external diameter to that of the disc or plug, the tube being fixably and concentrically attached to the underside of the disc or plug, all so as provide a method of engagement which is lightweight, durable, and of high structural integrity.

(21) A floodwater/sewage protection means for buildings as claimed in Claims 1-7 and 16-20, in which a lock-ring having both internal threads and a ring-seal which may be partially rebated fixably attached to its lowermost surface is screwed onto the body of the plug, the plug being provided with external threads such that with the ring-seal in contact with the upward-facing return of the outlet and the feet engaged under the radial ribs or that part of the linkage within the throat of the outlet, rotating the lock-ring will both firmly secure the feet and compress the ringseal so as to prevent dislocation of the plug and the penetration of sewer contents under pressure.

(22) A floodwater/sewage protection means for buildings as claimed in Claims 1,2, 5,7 and 17, in which the'pop-up'outlet may additionally have an outlet grid in the same or similar position to that of the outlet grid in a conventional outlet, the outlet grid having solid areas or radial ribs in the same way as a conventional outlet or as few as two which may be diametrically aligned, and at the centre of the

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grid a hole may have a tube concentncally aligned and fixably attached to the grid so as to loosely retain a rod In vertical alignment, the rod being fixably attached to the centre of a plug in the form of a disc at its upper end and at its lower end the rod may have a plain-headed bolt with head of the same diameter partially screwed into a concentrically threaded hole so that the plug may be withdrawn completely from the outlet when and as required, and the adjustment available by screwing or unscrewing the bolt is sufficient to ensure correct engagement of the plug in the outlet.

(23) A floodwater/sewage protection means for buildings as claimed in Claims 1 and 22, in which the disc is slightly smaller in diameter than the top of the outlet, and of thickness sufficient to accommodate a circumferential groove with a ringseal gasket partially rebated into it, such that when the plunger is pulled up the disc and the gasket are sealably engaged with the inside circumference of the outlet so as to effectively prevent water escaping whilst the appliance is in use, and when the plunger is pushed down water may flood under the disc into the drain.

(24) A floodwater/sewage protection means for buildings as claimed in Claims 1, 22,23, where the plug may have outwardly-extending shoulders so as to closely oversail the upwardly-facing return of the outlet, and additionally or alternatively the shoulders may have a concentric groove with a ring-seal gasket partially rebated into it so as to sealably engage with such return when the plunger is pushed down.

(25) A floodwater/sewage protection means for buildings as claimed in Claims 22,23 and 24, where the arrangement and methodology of the plug and outlet in normal use allows, in the same outlet, the installation and withdrawal of a separate and special plug having the arrangement and methodology of any of the previous embodiments or optional aspects hereinbefore claimed.

(26) A floodwater/sewage protection means for buildings as claimed in any of the preceding claims in which the touching surfaces of the foot and the solid area of the outlet grid or linkage may each be ramped either separately or together so as to positively increase the compression of the seals and progressively increase the

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pressure between the contact surfaces as the plug IS rotated to engage them together and, at the point where engagement is complete, a projecting ndge across the contact surface of either component snaps into a complementary slot on the other using the pressure existing between the surfaces, and so lock-out the two components in their operating position (27) A floodwater/sewage protection means for buildings as claimed in any of the preceding claims, in which ramp profiling of the foot, nb or linkage is achieved by moulding casting or machining a complementary inclined face on the engagement surfaces of either, or both, components by twisting or bending either, or both, components to the optimum angle of inclination.

(28) A floodwater/sewage protection means for buildings as claimed in Claims 1,26 and 27, in which the ridge may be hook-shaped and located along the leading edge of one component so as to hook over the trailing edge of the other to lock-out and complete the engagement, or alternatively the ridge may be of any convenient shape and disposition and the complementary slot or hole similarly, and be located anywhere within or adjoining the contact surfaces (29) A floodwater/sewage protection means for buildings as claimed in Claims 1 and 26-28 in which the'ridge and slot'and'hook and step'locking-out mechanism may also be applied independently, without any ramps.

(30) A floodwater/sewage protection means for buildings as claimed in Claims 1-17 and 20-25, in which the feet and lock-out mechanisms comprise. (1) engagement channels cut into the underside of the tube which is fixably attached to the disc or plug each channel having the form of a slot or inverted'V'into which the linkage or ribs engage when the plug is first rotated ; (2) a ramp forming a continuation of each engagement channel which compresses the seals on the plug against the complementary sealing surfaces on the outlet when the plug is pushed down and further rotated, and ; (3) a hole forming a continuation of each ramp, having the same cross-section as the linkage or rib, and being partially open on the side adjoining the ramp into which the linkage or rib IS forced and held captive

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when the plug IS rotated still further, so as to prevent dislocation of the plug or the penetration of sewer contents under pressure whilst enabling manual removal of the plug using the reverse process (31) A floodwater/sewage protection means for buildings as claimed in any of the preceding claims in which with three basic components, the full range of waste outlet applications can be fitted and so protect against backflow : (1) a special and dedicated'pop-up'outlet of the type described in the fifth embodiment having an upper portion which may be unscrewed and used independently without the 'pop-up'function where required, such upper portion being configured to accept a conventional plug in addition to the dedicated plug described and having external threads which may be configured to accept waste fittings meeting the requirements of the relevant British Standard (s); (2) a dedicated plug of the type described in the fifth embodiment, and ; (3) a separate and special plug having the form of the first, second, third, or fourth embodiments or optional aspects hereinbefore described, to be installed when flood conditions are anticipated.

(32) A floodwater/sewage protection means for buildings substantially as described herein with reference to Figures 1-12 of the accompanying drawings