Waste trap

Abstract

A waste trap 100, for trapping and removing solid waste from sewage water flowing into pumping station, having an inlet portion 102 connectable to a wastewater outlet in a pumping station holding tank

Description

The present invention relates to apparatus for trapping waste and in particular, but not exclusively, to a waste trap for separating non-biodegradable contaminants from black or grey water before it enters a pumping station. Pumping stations are used for a wide variety of applications including housing developments, schools, hospitals, commercial sites and even residential homes. As well as being used for situations where sewage cannot naturally be transported by gravity to a sewer system, they may be installed where the sewer passes over an incline, or just when it is a more cost-effective solution than a traditional gravity sewage system. Typically, sewage is first collected and stored in a chamber. When this reaches a predetermined level, an integral pump uses pressure to lift the sewage through a discharge pipe system and pumps the liquid into a gravity sewer or sewage treatment works. Levels are closely monitored by a liquid level sensor or float switch, which turns the pumping station on and off. Pumping stations may use one pump or more pumps depending on the application. However, these pumps are prone to becoming clogged by non-biodegradable contaminants, such as toilet paper, hair or sanitary products, etc. Clogged pumps with a full or partial blockage can quickly damage the pump itself or to other components in the system, cause backups and can generate hydrogen sulphide and its associated odours as a result of a layer of unwanted material rotting on top of the water. A significant number of hours are spent unclogging such pumps which is time consuming and costly in terms of the labour required and downtime of the pumping station. It is an aim of certain embodiments of the present invention to provide a waste trap assembly that prevents solids, such as sanitary products, entering a pump of a pumping station and which is non-complex and easy to clean and maintain. It is an aim of certain embodiments of the present invention to provide a waste trap assembly that prevents solids, such as sanitary products, entering a pump of a pumping station and which is retrofittable to an existing inlet of a pumping station. According to a first aspect of the present invention there is provided apparatus for trapping waste, comprising: an inlet portion connectable to a waste water outlet; and a trap assembly for trapping solid contaminants in waste water from the waste water outlet, wherein an inlet end region of the trap assembly is coupled to the inlet portion by a coupling and is moveable under gravity from a first position to a second position with respect to the inlet portion responsive to a weight of the trap assembly including contaminants trapped therein being more than or equal to a predetermined threshold weight defined by a coupling force of the coupling. Optionally, the coupling comprises a spring to urge the trap assembly towards the first position and the coupling force comprises a spring force of the spring. Optionally, the coupling comprises a first hinge defining a first hinge axis about which the trap assembly is rotatable between the first and second positions, and wherein the spring comprises a torsion spring. Optionally, the coupling comprises a magnet to hold the trap assembly in the first position and the coupling force comprises a magnetic force of the magnet. Optionally, the apparatus comprises a switch or sensor operably connected to a controller to indicate to a user when the trap assembly is in the second position. Optionally, the switch or sensor comprises a magnetic reed switch having a first switch part located on the inlet portion and a second switch part located on the trap assembly. Optionally, the apparatus comprises at least one level sensor operably connected to the controller to indicate to a user when a level of trapped contaminants in the trap assembly is more than or equal to a predetermined level. Optionally, the at least one level sensor comprises an infrared sensor located on the trap assembly. Optionally, the trap assembly comprises an elongate channel member comprising the inlet end region, an outlet end region, and a substantially U-shaped cross section. Optionally, each of a plurality of spaced apart protrusions extend upwardly from or through a base of the channel member for trapping solid contaminants in waste water flowing towards the outlet end region in use. Optionally, the channel member comprises a plurality of spaced apart apertures each for receiving a corresponding one of the protrusions, and wherein the trap assembly comprises a substantially curved trap member comprising the protrusions and located below the channel member and coupled thereto by a second hinge defining a second hinge axis about which the trap member is rotatable with respect to the channel member between a closed position wherein the protrusions extend upwardly through the apertures in the channel member and an open position wherein the protrusions have been moved downwardly out of the apertures in the channel member. Optionally, the second hinge comprises a torsion spring to urge the trap member towards the closed position. Optionally, the apparatus comprises a magnetic coupling between the trap member and the channel member for holding the trap member in the closed position. Optionally, the channel member comprises the protrusions and the trap assembly comprises a substantially curved scraper member comprising a plurality of spaced apart apertures each for receiving a corresponding one of the protrusions, and wherein the scraper member is located in the channel member and coupled thereto by a second hinge defining a second hinge axis about which the scraper member is rotatable with respect to the channel member between a closed position wherein the protrusions extend upwardly through the apertures in the scraper member and an open position wherein the apertures have been moved upwardly away from the protrusions of the channel member. Optionally, the second hinge comprises a torsion spring to urge the scraper member towards the closed position. Optionally, the channel member comprises a raised island region proximal to the inlet end region to bifurcate waste water flowing along the channel member. Optionally, each protrusion is substantially shark fin-like defining a concave upstream edge and a convex downstream edge which terminate at a point. Optionally, the plurality of protrusions is arranged in a substantially triangular formation which widens towards the outlet end region of the channel member. Optionally, the inlet portion is substantially tubular. According to a second aspect of the present invention there is provided a pumping station comprising apparatus according to the first aspect of the present invention. Description of the Drawings Certain embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 illustrates an isometric view of a waste trap according to certain embodiments of the present invention in an empty and normal operating state; Figure 2 illustrates the waste trap of Figure 1 in a full and weighted state; Figure 3 illustrates the waste trap of Figure 2 in a cleaning / emptying state; Figure 4 illustrates a plan view of the waste trap of Figure 1; and Figure 5 illustrates a side view of the waste trap of Figure 1. Detailed Description As illustrated, apparatus 100 according to certain embodiments of the present invention include a tubular inlet portion 102 which has a substantially circular cross section to connect to an existing inlet of a sewerage pumping station. The inlet portion is around 100 mm long and has a diameter of around 100mm. The inlet portion 102 may have a different shape of cross section, such as square, to correspond with the existing inlet of the pumping station and it may connect to the exiting inlet via an interference fit and / or a clamp or the like. A trap assembly 104 is coupled to the inlet portion 102 by a first hinge 105, wherein a first part of the hinge is an integral portion of the inlet portion and a second part of the hinge is an integral portion of the trap assembly. The first hinge 105 includes a torsion spring to urge the trap assembly 104 towards a substantially horizontal position (as shown in Figures 1 and 5) and hold the same in that position when a weight of the trap assembly, including any contaminants trapped therein, is less than a predetermined threshold weight. A spring force of the torsion spring can be selected to correspond with the desired predetermined threshold weight. Alternatively, or additionally, other coupling means may be used to hold the trap assembly 104 up in the horizontal position, such as one or more magnets, tension springs, clips or the like, until a weight of the trap assembly, including any contaminants trapped therein, overcomes a force holding the trap assembly in the horizontal position. The trap assembly 104 includes an elongate and substantially U-shaped channel member 106 for receiving and containing waste fluid flowing from the inlet portion 102 and directing the same into the pumping station chamber wherein at least one pump is located. The channel member 106 is substantially semi-circular in cross section. The channel member 106 includes a relatively narrow inlet end region 108 having a radius of curvature substantially corresponding to the inlet portion 102, and a relatively wide outlet end region 110. The inlet end region is located above the outlet end region to define a neck region 109, i.e. the channel member 106 is substantially half bottle-shaped. This arrangement encourages waste water to flow under gravity towards the outlet end region. A raised island region 114 in the base of the channel member 106 is substantially triangular in plan profile and oriented such that the narrow end thereof is proximal to the inlet end region 108. Alternatively, the raised region may be substantially diamond shaped in plan profile. The raised region 114 splits or bifurcates the flow of waste water entering the channel member 106 and has curved corner regions to encourage smooth laminar flow therearound and to prevent turbulence. The entire surface of the raised region is substantially curved and smooth to prevent contaminants snagging thereon as the waste water flows past. The raised region 114 prevents the waste water and any solid contaminants therein from always flowing over a central region of the channel member 106 and instead spreads the flow efficiently across the base of the channel portion, as described further below. The channel member 106 includes a plurality of spaced apart slotted through apertures 116 arranged in a triangular formation which widens towards the outlet end region 110, as best shown in Figure 4. Each slot 116 is oriented longitudinally and has a length of around 5-15 mm and a width of around 3-5 mm at its widest point. The channel member 106 is around 345 mm long and has a radius of curvature of around 50 mm at the narrow inlet end region 108 and around 100 mm at the wide outlet end region 110. The trap assembly 104 further includes an elongate and substantially U-shaped trap member 118 for trapping and retaining solid contaminants, such as hair and sanitary products, in the waste water flowing along the channel member 106. The trap member 118 is coupled to the channel member 106 by a second hinge 120, wherein a first part of the hinge is an integral portion of the channel member 106 and a second part of the hinge is an integral portion of the trap member 118. The second hinge 120 includes a torsion spring to urge the trap member 118 towards a substantially horizontal closed position as shown in Figure 4. A spring force of the spring may be sufficient to hold the trap member in the closed position during use and resist any downward forces acting thereon as a result of the flowing waste water and weight of any trapped contaminants. Alternatively, as illustrated in Figure 5, the trap member 118 may be coupled to the channel member 106 to hold it in the closed position by one or more coupling means 112, such as a magnet, clip or the like, whilst allowing the trap member 118 to be selectively decoupled from the channel member 106 when required, as described further below. The trap member 118 includes a tab region 122 which extends beyond the outlet end 110 of the channel member 106 when the trap member 118 is in the closed position and which acts as a handle for a user to grip to rotate the trap member downwardly away from the closed position and against the spring force of the torsion spring, as described further below. The channel member 106 aptly includes a recessed region 125 in its underside to accommodate the trap member 114 when stowed in the closed position. The trap member 118 includes a plurality of spaced apart spiked protrusions 124 upwardly extending from its upper surface and arranged in a triangular formation which widens towards a free end region 126 of the trap member 118 to correspond with the through apertures 116 in the channel member 106, as best shown in Figure 4. When the trap member 118 is in the closed position, each protrusion 124 extends through a corresponding one of the slotted apertures 116, as shown in Figure 1. Each protrusion 124 is substantially shark fin-like defining a concave upstream edge 128 and a convex downstream edge 130 which terminate at a point. This fin profile helps to efficiently, and consistently, trap and retain solid contaminants in the waste water flowing along the channel member 106. Alternatively, the protrusions may be substantially straight elongate pins or spikes or the like. The triangular formation of the protrusions 124 helps to spread out the trapped contaminants in correspondence with the bifurcated flow of waste water around the raised island region 114 of the channel member 106, whilst preventing a build-up of trapped contaminants proximal the raised island region 114 which could impede flow and compromise the performance of the apparatus. This arrangement also traps more contaminants proximal to the outlet end region 110 of the channel member 106 first to ensure all the trapping protrusions are utilised before the trap assembly requires emptying. This arrangement also locates much of the weight of the trapped contaminants proximal to the outlet end region 110 of the channel member 106 to thereby apply a moment nearer to that end of the trap assembly to ensure the same drops to the open position when the predetermined threshold weight has been exceeded. In use, waste water flows from the pumping station inlet, through the inlet portion 102 of the apparatus 100, and on to the channel member 106. The flow of waste water is split by the raised island region 114 and evenly distributed along the channel member and through the spiked protrusions 124 of the trap member 118. Any solid contaminants, such as hair or sanitary products, are caught on the spiked protrusions and the waste water continues to flow off the outlet end region 110 of the channel member 106 and into the pumping station chamber for pumping. When the build-up of contaminants on the spiked protrusions 124 has reached a certain amount, wherein the weight of the trap assembly 104 exceeds the predetermined threshold weight defined by the spring force of the torsion spring and / or a magnetic force of a magnetic coupling for example between the channel member 106 and the inlet portion 102, the trap assembly 104 drops about the axis defined by the first hinge 105. Aptly, the apparatus 100 includes at least one switch or sensor, such as a magnetic reed switch, with is activated responsive to the trap assembly 104 moving from the closed position to the open position with respect to the inlet portion 102 when a weight of the trap assembling, including trapped contaminants, exceeds the predetermined threshold weight. The switch or sensor is operably coupled to a controller and sends a signal thereto via a wired or wireless connection to indicate to the controller that the trap assembly 104 is full and has been moved to the closed position by the weight of the trapped contaminants. One or more additional sensors may be provided to indicate to the controller that the trap assembly 104 is full, such as at least one infrared sensor located behind a transparent protective window in the channel member 106 and configured to direct a beam of infrared light across the channel member which is broken when the same is full of trapped contaminants. This may be desirable if the weight of trapped contaminants is not sufficient to exceed the predetermined threshold weight defined by the spring force of the torsion spring located in the first hinge 105 for example. Aptly, the controller is configured to communicate wirelessly with a mobile device, such as a tablet or mobile phone, associated with an authorised user to indicate the trap assembly needs emptying. The apparatus may include one or more additional sensors to monitor other parameters, such as waste water flow rate through the apparatus or the like. To empty the trap assembly 104, the user pulls down the trap member 118 by applying a downward force on the tab region 122 to overcome the spring force of the torsion spring in the second hinge 120 coupling the trap member 118 to the channel member 106. This rotational movement of the trap member 118 away from the channel member 106, as shown in Figure 3, pulls the contaminants trapped on the projections 124 downwardly against the base of the channel member and scrapes the contaminants off the projections as they exit downwardly through their respective slotted apertures 116. The contaminants can then be easily removed from the channel member by the user and the trap member can then be restowed in the closed position with respect to the empty channel member. Aptly, the inlet portion 102, channel member 106 and trap member 118 all comprise a plastics material, such as Acrylonitrile Butadiene Styrene (ABS) or the like, and are formed by injection moulding or the like. Alternatively, the apparatus may be made from a metal material, such as stainless steel if, for example, its application is in a medical or food processing environment. In an alternative embodiment of the present invention, instead of a rotatable trap member being coupled below the channel member and including the spiked protrusions for pulling trapped contaminants of the protrusions as they exit the apertures in the channel member, the channel member may include the protrusions upwardly extending from its base. A curved scraper member may be hingedly coupled to the channel member, such as proximal to the raised island region 114, and sit in its base downstream of the raised island region. The scraper member may include a plurality of apertures for receiving each of the protrusions and be lifted about its hinge axis when the trap assembly requires emptying / cleaning to thereby scrape the trapped contaminants upwardly off the protrusions. The contaminants can then be removed from the scraper member before the same is rotated back to its resting position in the base of the channel member. In either embodiment, the protrusions may be shark fin-like protrusions as illustrated or they may take a different form such as substantially straight elongate pins, spikes, or the like. The pins / spikes may be around 20-50 mm long and around 2-3 mm in diameter, and the corresponding holes in the channel member or the scraper member would be sized and shaped accordingly. Certain embodiments of the present invention therefore provide an apparatus for trapping waste that prevents solids, such as sanitary products, entering a pump of a pumping station and which is non-complex and easy to clean and maintain. Aptly, the apparatus according to certain embodiments of the present invention requires no power and / or is retrofittable to an existing inlet of a pumping station or other waste inlet or outlet.

Claims

1. Apparatus for trapping waste, comprising:an inlet portion connectable to a waste water outlet; anda trap assembly for trapping solid contaminants in waste water from the waste water outlet,wherein an inlet end region of the trap assembly is coupled to the inlet portion by a coupling and is moveable under gravity from a first position to a second position with respect to the inlet portion responsive to a weight of the trap assembly including contaminants trapped therein being more than or equal to a predetermined threshold weight defined by a coupling force of the coupling.

2. The apparatus according to claim 1, wherein the coupling comprises a spring to urge the trap assembly towards the first position and the coupling force comprises a spring force of the spring.

3. The apparatus according to claim 2, wherein the coupling comprises a first hinge defining a first hinge axis about which the trap assembly is rotatable between the first and second positions, and wherein the spring comprises a torsion spring.

4. The apparatus according to any preceding claim, wherein the coupling comprises a magnet to hold the trap assembly in the first position and the coupling force comprises a magnetic force of the magnet.

5. The apparatus according to any preceding claim, comprising a switch or sensor operably connected to a controller to indicate to a user when the trap assembly is in the second position.

6. The apparatus according to claim 5, wherein the switch or sensor comprises a magnetic reed switch having a first switch part located on the inlet portion and a second switch part located on the trap assembly.

7. The apparatus according to claim 5 or 6, comprising at least one level sensoroperably connected to the controller to indicate to a user when a level of trapped contaminants in the trap assembly is more than or equal to a predetermined level.

8. The apparatus according to claim 7, wherein the at least one level sensor comprises an infrared sensor located on the trap assembly.

9. The apparatus according to any preceding claim, wherein the trap assembly comprises an elongate channel member comprising the inlet end region, an outlet end region, and a substantially U-shaped cross section.

10. The apparatus according to claim 9, wherein each of a plurality of spaced apart protrusions extend upwardly from or through a base of the channel member for trapping solid contaminants in waste water flowing towards the outlet end region in use.

11. The apparatus according to claim 10, wherein the channel member comprises a plurality of spaced apart apertures each for receiving a corresponding one of the protrusions, and wherein the trap assembly comprises a substantially curved trap member comprising the protrusions and located below the channel member and coupled thereto by a second hinge defining a second hinge axis about which the trap member is rotatable with respect to the channel member between a closed position wherein the protrusions extend upwardly through the apertures in the channel member and an open position wherein the protrusions have been moved downwardly out of the apertures in the channel member.

12. The apparatus according to claim 11, wherein the second hinge comprises a torsion spring to urge the trap member towards the closed position.

13. The apparatus according to claim 11 or 12, comprising a magnetic coupling between the trap member and the channel member for holding the trap member in the closed position.

14. The apparatus according to claim 10, wherein the channel member comprises the protrusions and the trap assembly comprises a substantially curved scraper member comprising a plurality of spaced apart apertures each for receiving a corresponding one of the protrusions, and wherein the scraper member is located in the channel member and coupled thereto by a second hinge defining a second hinge axis about which the scraper member is rotatable with respect to the channel member between a closed position wherein the protrusions extend upwardly through the apertures in the scraper member and an open position wherein the apertures have been moved upwardly away from the protrusions of the channel member.

15. The apparatus according to claim 14, wherein the second hinge comprises a torsion spring to urge the scraper member towards the closed position.

16. The apparatus according to any of claims 9 to 15, wherein the channel member comprises a raised island region proximal to the inlet end region to bifurcate waste water flowing along the channel member.

17. The apparatus according to any of claims 10 to 16, wherein each protrusion is substantially shark fin-like defining a concave upstream edge and a convex downstream edge which terminate at a point.

18. The apparatus according to any of claims 10 to 17, wherein the plurality of protrusions is arranged in a substantially triangular formation which widens towards the outlet end region of the channel member.

19. The apparatus according to any preceding claim, wherein the inlet portion is substantially tubular.

20. A pumping station comprising apparatus according to any preceding claim.

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