GB2283409A - Washing refuse bins - Google Patents

Abstract

A method for cleaning residual material from emptied refuse containers includes the steps of supporting a container 2 in an at least partially inverted position above a fluid collection means eg a tray 16 having a sump 17 and a mesh cover 18; spraying wash fluid eg hot water on the container and allowing it to drain to the collection means; and recirculating at least a part of the collected fluid through a solids separation device eg filters 22. The container may be supported in its inverted position by means comprising a trolley member 11 which travels on a pair of inclined rails 10 above the fluid collection means, the trolley having cross bars 13 to engage the wheels 6 of the container. In this arrangement the container is inverted by pushing it upwards parallel to the rails until a handle 7 of the container engages hooks 15. Apparatus for carrying out the method may be mounted in the body of a van. <IMAGE>

Description

TITLE: METHOD AND APPARATUS BACKGROUND TO THE INVENTION: Domestic and other refuse and waste material (for convenience collectively denoted hereinafter as refuse) is typically collected initially in a refuse container from which the refuse is collected for disposal at a land infill site, incinerator or other large scale waste treatment or disposal site. Thus, for example, domestic waste is collected in a dustbin which may be static, or on wheels (known as a wheely-bin) to permit transport to a collection lorry or the like. The waste is collected from the dustbin on a weekly basis by a refuse collection vehicle and disposed of as land infill.

However, some of the waste remains adherent to the interior walls of the dustbin and can begin to decompose with attendant smells and health hazards. It has been proposed to wash out the interior of the dustbin after its contents have been tipped into the refuse collection lorry. However, this generates water which is contaminated with decomposing vegetable and other material. For safety reasons, this contaminated wash water cannot be allowed to flow into the surface water drainage system, which is usually the only accessible disposal location available to those washing the dustbins. The use of such a proposal has therefore been prohibited by local authorities unless adequate storage facilities for the contaminated water are provided to prevent escape of contaminated water into the surface drainage system.If a number of dustbins are to be cleaned, it is necessary to provide considerable amounts of water and this then requires a substantial vehicle to carry not only the cleaning apparatus, but also the water by way of clean water to clean the dustbins and by way of contaminated water which must be retained on the vehicle. This makes such a proposal uneconomic.

We have now devised a method and apparatus by which dustbins and other containers of waste materials can be cleansed after the waste has been removed from the container.

SUMMARY OF THE INVENTION: Accordingly, the present invention provides a closed loop method for cleansing residual waste material from a container for such waste material from which substantially all of the waste material has been removed, which method comprises the steps of: a. supporting the substantially empty container in an at least partially inverted position above a wash fluid collection means; b. applying wash fluid to the interior of the container so as to displace residual waste material therefrom; c. allowing the wash fluid to flow from the container to the fluid collection means; and c. passing at least part of the wash fluid from the fluid collection means through a solids separation device for re-use in cleansing the or another container so as to form a substantially closed loop for the circulation of the cleaning fluid.

The invention also provides a closed loop circulation apparatus for use in the method of the invention which comprises: a. means for supporting a container in an at least partially inverted position above a fluid collection means; b. means for applying wash fluid to the interior of the supported container so as to displace residual waste material from the container; c. a wash fluid collection means adapted to receive wash fluid and residual waste material from the interior of the supported container; d. means for removing wash fluid from the fluid collection means and for passing the removed fluid through a separation means so as to render the fluid suitable for re-use and thus form a substantially closed circulation loop for the cleaning fluid in the apparatus.

The term closed circulation loop is used herein to denote that substantially no fluid escapes from the system during the use of the fluid to clean the container and the recirculation of that fluid. It will be appreciated that the system itself may be open to the environment so long as the flow path of fluid through the system is designed to minimise escape of fluid into that environment.

The invention can be applied to the removal of a wide range of types of solid, waxy, oily or fluid waste from a wide range of types of container. However, the invention is of especial application in the removal of domestic waste residues from containers for domestic waste after the majority of the waste has been discharged from the container into a refuse collection vehicle. The container can be a conventional generally cylindrical or frusto-conical open topped dustbin having a length to breadth ratio of from about 1.5:1 up to about 4:1. However, the invention is of especial application to refuse containers which have one or more pairs of wheels at their base and are of a tapered generally squared cross-section. Such containers are commonly known as wheely-bins.For convenience, the invention will be described hereinafter in terms of the removal of domestic waste residues from a wheely-bin type of container.

Preferably, the wash fluid is water and this is applied as a pressure jet or spray into the inverted container which is supported by the support means within a wash zone. The pressurised jet or spray can be generated by any suitable means, for example a conventional high pressure water jet machine and many forms of such machines are available commercially. For convenience, the invention will be described hereinafter in terms of the use of a commercially available water jet comprising a pump generating a continuous or pulsed flow water at a pressure of from 10 to 150 bar which is discharged through a nozzle at the end of a lance or arm to give a jet or spray of wash water whose direction can be controlled by an operator wielding the lance or arm manually.

The spray can be a narrow angle spray or can be a fish tail spray, depending upon the tenacity with which the residual waste material adheres to the walls of the container. If desired, the wash water can contain one or more chemicals to assist the removal of adherent solids from the wall of the containers and/or to aid suspension of the solids in the wash water, to sanitise the interior of the container and/or to sanitise the waste particles dislodged from the container wall. The water can be heated, for example to 40 to 600C, or can be used at least in part in the form of steam. For convenience, the invention will be described hereinafter in terms of the use of water at ambient temperature without any added chemicals.

The fluid collection means is preferably a tray or pan located below the inverted container and into which the wash fluid drains under gravity from the container. Preferably, the fluid collection means is provided with a screen, mesh or other apertured cover through which the wash water flows, so as to remove large sized waste solids from the wash water. For example, the collection means can take the form of an open topped generally horizontal pan extending over at least the plan area onto which water draining from the container will fall. Such a pan can be made from metal, plastic, ceramic or other water resistant material using any suitable fabrication technique.The pan preferably has a mesh or pin hole apertured sheet cover overlying the open top of the pan so that water draining from the inverted container has to pass through the apertures of the cover sheet, whereby paper and other large solids washed out of the container are retained on the cover whilst the wash water drains into the pan. Typically, the cover has apertures of from 1 to 10 mms size therein so as to allow free flow of the wash water through the apertures and yet to remove the majority of solids from the water.

The water collection means preferably has side cheeks which extend upwardly from the base of the means to collect substantially all of the wash water sprays which may escape laterally from the open top, now the base, of the inverted container. It is also preferred that the water collection means is provided with means whereby fine particle sized material which has passed through the apertures of the cover sheet can settle out or be separated from the water in the pan. Thus, the pan preferably has a sump portion or other means into which small particle sized solids can settle. It is also preferred to provide the pan with baffles or other means which prevent uncontrolled movement of water within the pan where the cleaning apparatus is mounted on a vehicle for transport. The baffles may also assist separation of solids from the water by reducing the rate of flow of water through the pan.

The container is supported by the support means in an inverted orientation above the water collection means.

Preferably, the support means is configured so that the container is supported with its longitudinal axis at an angle of from 30 to 900 to the horizontal so that wash fluid fed into the container will inherently drain from the container. Preferably, the orientation is also such that the interior of the container is visible to an operator of the lance or other means by which the wash fluid is fed to the container, whereby the operator can direct the jet or spray of fluid to displace adherent waste from the interior walls of the container.

Preferably, the support means is provided by one or more inclined rails upon which the base, which is now uppermost, of the inverted container is carried for movement from an inoperative position to an operative position at which it is inverted at the required angle and is located above the fluid collection means. The rails can be static, in which case the container is moveable upon the rails or is provided with a trolley or other means whereby the container can be located and moved upon the rails. Alternatively, the support means can be articulated or rotated so as to transport a container suspended from them from the inoperative position to the operative position.

The container is secured to the rails, wheel or other support means by engagement of part of the container with the support means, as when the wheels of a wheely-bin engage in grooves or tracks carried by the support rails or in a trolley carried by the rails. Alternatively, the base of the container can be secured to the support means by a suitable ring or other clamp mechanism or by hooks.

In a particularly preferred embodiment, the wheels at the base of a wheely-bin are located in recesses or other locating means in a trolley carried by a pair- of inclined rails or in the gap between two cross bars linking trolleys carried upon the rails. The trolley travels upwards upon the rails to elevate the base of the bin whilst the operator allows the open top of the bin to pivot downwards whereby the bin adopts an inverted position. When the base of the bin has reached the desired elevation the bin is secured in position. For example, the handle which is usually located externally at the top of the bin to enable it to be wheeled about by a user, can be engaged with hooks carried by the rails or by other means to secure the bin upon the rails at the desired position.Other means for securing the bin in position can readily be devised, for example a locking bar can be secured across the rails to prevent the trolley carrying the wheels of the bin from moving downwardly upon the rails.

If desired, the rails can be extensible to provide a portion which extends to the ground level to permit the wheels or base of the bin to be engaged by moving the bin into engagement with the foot of the rails without the need to lift the bin to the level of raised rails. The rails then extend in an upward curve or line to lead into the inclined rails described above.

The water collection pan or other collection means is provided with a means for returning some or all of the collected wash water to the input to the pump generating the pressure jet or spray. Since the removal of solids from the wash water draining from the container by the apertured cover and the settlement of solids within the pan is not complete, water from the pan is passed through one or more filters, cyclones or other means for separating solid particles from the water. The water from such separator(s) is then suitable for re-use either as a direct or indirect feed to the pump generating the pressure spray or jet.

Preferably, the water is passed to a storage tank from which the pump of the pressure spray draws its supply and such tank can be provided with internal baffles or the like to prevent uncontrolled flow of water within the tank where the apparatus is mounted in a vehicle for transport. If desired, the tank can be fitted with a heater and/or chemical injection or dosing means to enhance the cleansing properties of the water fed to the pressure spray generating means. The storage tank can be located below the level of the water collection pan, so that water flows entirely by gravity from the inverted container to the inlet to the pump generating the spray or jet or to the storage tank.

However, it is preferred to pump the water from the pan to the storage tank so that the rate at which water is circulated through the container cleaning and water recycle stages is enhanced and the total amount of water within the apparatus is minimised.

If desired, means can be provided for mechanically assisting removal of material from the walls of the container. For example a rotating or other brush mechanism can be provided.

Means for drying and/or spraying sanitising or other fluids into the cleaned container may also be provided. However, it will usually be preferred that these functions be carried out manually by the operator using conventional brushes, squeegee mops, sprays and the like.

Preferably the above components of the apparatus are housed within a housing, for example the body of a closed van type of vehicle, so that the washing of the inverted containers is achieved within a substantially water proof enclosure to limit the amount of contaminated water which escapes into the environment. Thus, it is particularly preferred to mount the water collecting pan in the base of a box van type vehicle, to provide the inclined rails or other means for supporting the inverted container in the headroom of the van body above the pan so that they are accessible through the rear doors of the van body.The recycle pump, the pressure spray generating pump, water filters and associated pipework are preferably located in a partitioned off section of the van body so that the cleaning of the containers is carried out in a self contained "booth" with the operating parts for the generation of the pressure spray and the recycling of the water being accessible separately from the cleaning "booth". Such a construction can be readily incorporated into a small truck or van so as to provide apparatus which can be transported on the roads to follow a dustbin clearing crew, and yet maintains the separation of the contaminated wash water from the environment.When the cleaning operation is completed, for example at the end of the day or when the water being re-cycled is too dirty for re-use, the apparatus can be driven to a foul water disposal point adapted to handle contaminated water and the contaminated water discharged from the storage tank. Since the water is re-cycled, the amount of water which is required is reduced as compared to apparatus where the water is not re-cycled and hence the apparatus is more compact and requires a smaller vehicle. Furthermore, the amount of contaminated water which has to be disposed of is reduced.

The invention has been described above in terms of apparatus in which the operator loads the container onto the support means, inverts the container and carries out the washing process manually. Such apparatus can thus readily be operated with the minimum of skilled training as part of a low cost refuse collection operation. However, it is within the scope of the present invention to mechanise some or all of the operations of the apparatus. Thus, for example, the operator could present a wheely-bin in the normal upright orientation to an hydraulically operated lifting and inverting mechanism driven from the engine of the vehicle on which the apparatus is carried.The lifting mechanism then lifts and inverts the container and transports it into the washing "booth" within which is located a spray head on a suitable transport mechanism which traverses the interior of the inverted container under the control of optical or mechanical sensors to carry out the washing operation automatically. If desired, the doors of the "booth", for example the back doors of the van body, can be closed during the cleaning process to further reduce the risk of escape of contaminated water into the environment.

DESCRIPTION OF THE DRAWINGS: To aid understanding of the invention, a preferred embodiment will now be described by way of example with respect to the accompanying drawings in which Figure 1 is a diagrammatic side sectional view through a van body carrying the apparatus of the invention; and Figure 2 is a forward view of the cleaning "booth" portion of the van body of Figure 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT: The apparatus comprises a van chassis having a box van body 1 with a rear entry pair of doors or a roller blind type door (not shown) through which an operator introduces a wheely-bin 2 or other refuse container which is to be cleaned. The body 1 is divided by a vertical partition 3 into the rearward cleaning "booth" section 4 and a forward section 5, which houses the pumps, tanks and filters for circulating the water.

Within the "booth" 4 are mounted a pair of parallel inclined U section rails 10 upon each which is carried a trolley 11 whose wheels 12 run in the U channel of the rails 10. The trolleys are linked by a pair of cross bars 13 which form a socket or recess 14 into which the wheels 6 of the wheelybin locate. If desired, locking catches or the like can be provided to secure the wheels 6 or some other part of the bin 2 to the trolleys 11.

The rails 10 also each carry a hook 13 which engages with the handle 7 located externally adjacent the lip of the open top of the bin 2 so as to secure the bin 2 against downward movement on rails 10.

The bottom of the "booth" section 4 of the van body is provided with a generally rectangular plan shaped open topped water collection well or tray 16 which underlies the rails 10 and the plan area over which water will drain from the inverted bin 2. The well or tray 16 is formed with a sump section 17 into which solids can settle. The well or tray 16 has a mesh cover 18 which serves to trap large solids material flushed from the bin 2. Preferably, the cover 18 is removable to permit cleaning of the well or tray 16 and the removal of solids from sump 17. As shown in Figure 2, the side walls 19 of the well or tray 16 can be inclined to aid flow of water into the sump section 17 and these side walls 19 can be extended upwards to provide catchment surfaces for water splashing out of the open end of bin 2.

In section 5 there is mounted a water storage tank 20 which feeds water to a pressure pump 21. Preferably one or more filters 22, for example cartridge filters, are provided in the pipe connecting tank 20 to the inlet to pump 21. Pump 21 feeds water under high pressure to a jetting or spray nozzle 23 carried on a lance 24 via a flexible hose 25. A second pump 26 is connected to well or tray 16 via one or more fine and coarse filters 27 and pipe 28 so as to draw water from well or tray 16 and feed it to the storage tank 20 via pipe 29. If desired, level sensors (not shown) can be located in tank 20 to actuate pump 26 when the water level in the tank falls below a specified level.

In operation, a bin 2 is lifted so that the wheels 6 at its base engage in the gap 14 between cross bars 13 of the trolleys 11, which are located at the lower, rearward end of the rails 10. If this has not already been done in offering the bin wheels up to the trolleys, the bin 2 is pivoted to adopt a partially inverted position at which its longitudinal axis is approximately parallel to the rails 10.

The operator then pushes the bin in a direction parallel to the rails to cause the base of the bin to travel up the rails until the handle 7 of the bin can be engaged in the hooks 15 to secure the bin in the position shown in Figure 1. The bin 2 will usually have a pivoted lid 8 which falls open as the bin 2 is inverted and lies between the rails 10 to provide a splash back which minimises escape of water from the open end of the bin into the forward portion of the "booth" 4. The bin is secured at an angle of about 70 to 800 to the vertical as shown in Figure 1.

The operator then inserts the nozzle 23 into the interior of the bin 2 and begins to play an high pressure jet or spray of water over the interior of the bin to dislodge solids and other waste residues from the walls of the bin. These are flushed out of the open end of the bin and are trapped on cover 18 as the water flows into well or tray 16. If required, the operator can apply a brush or scraper to resistant deposits on the bin wall.

The water within well or tray 16 contains solids which settle out into the sump section 17 below the level of pipe 28. When the well or tray 16 is full or if tank 20 shows that it is empty, the operator actuates pump 26 to draw water from well or tray 16 through filters 27 and feed the water into tank 20 via pipe 29. As indicated above, this can be achieved automatically under the control of sensors in tank 20 or manually.

When the bin 2 has been cleaned, the operator can dry the interior of the bin with a squeegee mop, a cloth or a hot air drier and can spray disinfectant and/or de-odouriser fluid into the interior of the bin. The handle 7 is released from hooks 15 to allow the bin to slide along rails 10 until the wheels 6 reach the bottom of rails 10. The wheels 6 are then disengaged from the trolleys 11, the bin inverted to adopt the normal upright position and returned in a clean condition to its owner.

Since the cleaning water has been retained in the "booth" 6 and is circulated from well or tray 16 to tank 20 for reuse, little or no water contaminated with waste materials is released into the environment.

The invention has been described above in terms of a single pair of rails 10 in the "booth" 6. However, where the van body 1 is large enough or the width of the bin 2 is small enough, two or more parallel sets of rails 10 may be used, thus enabling two or more bins 2 to be cleaned simultaneously.

Claims (14)

CLAIMS:

1. A closed loop method for cleansing residual waste material from a container for such waste material from which substantially all of the waste material has been removed, which method comprises the steps of: a. supporting the substantially empty container in an at least partially inverted position above a wash fluid collection means; b. applying wash fluid to the interior of the container so as to displace residual waste material therefrom; c. allowing the wash fluid to flow from the container to the fluid collection means; and c. passing at least part of the wash fluid from the fluid collection means through a solids separation device for re-use in cleansing the or another container so as to form a substantially closed loop for the circulation of the cleaning fluid.

2. A method as claimed in claim 1, characterised in that the container is a domestic refuse collection container.

3. A method as claimed in either of claims 1 or 2, characterised in that the wash fluid is water and is applied as a pressurised spray and/or jet to the interior of the container.

4. A method as claimed in claim 3, characterised in that the water is applied at elevated temperature and/or as steam.

5. A method as claimed in any one of the preceding claims, characterised in that the fluid collection means comprises a pan or tray located below the inverted container and having an apertured cover through which the -water drains under gravity.

6. A method as claimed in claim 5, characterised in that the pan or tray has a sump portion into which at least part of the solids which pass through the apertured cover can settle.

7. A method as claimed in any one of the preceding claims, characterised in that a filter means is provided for separating at least part of the solids therein from cleansing fluid which is recycled from the wash fluid collection means for re-use.

8. A method as claimed in any one of the preceding claims, characterised in that the container is supported in its inverted position by a support means comprising a trolley member which travels upon a pair of inclined rails located above the wash fluid collection means.

9. A method as claimed in claim 8, characterised in that the base of the container is engaged with the trolley means in a lower position with the container in an upright orientation and transported up the inclined rails whilst the container is pivoted upon the trolley means to adopt the desired inverted orientation.

10. A method as claimed in any one of the preceding claims, characterised in that the washing of the container and the collection of the wash fluid from the container is carried out in a structure separated by a substantially water impervious partition from the wash fluid solids separation and re-cycling means.

11. A method as claimed in claim 1 substantially as hereinbefore described with respect to the accompanying drawings.

12. A closed loop circulation apparatus for use in the method of claim 1 which comprises: a. means for supporting a container in an at least partially inverted position above a fluid collection means; b. means for applying wash fluid to the interior of the supported container so as to displace residual waste material from the container; c. a wash fluid collection means adapted to receive wash fluid and residual waste material from the interior of the supported container; d. means for removing wash fluid from the fluid collection means and for passing the removed fluid through a separation means so as to render the fluid suitable for re-use and thus form a substantially closed circulation loop for the cleaning fluid in the apparatus.

13. Apparatus as claimed in claim 12, characterised in that it is mounted within the body of a van type of motor vehicle.

14. Apparatus as claimed in claim 13, characterised in that the body is provided with partition means to separate the container and wash collection means from the means for separating solids from the wash fluid and the fluid recycling means.