GB2296489A - Removing waste from a container - Google Patents

Abstract

Hazardous waste is removed from a container by engaging against the exterior of the container a pair of tool heads 10. Each tool head has a resilient sealing arrangement 14 - 20 for sealing against the container, and a hollow drill 28 which can be advanced by a motor 26 and cam arrangement or by a pressure ram to breach the container. The drill of one tool head communicates via a conduit 38 with a source of flushing liquid and the drill of the other head communicates with a drain vessel. The resilient sealing arrangement is preferably hollow and a negative pressure may be applied thereto to force the arrangement against the container. <IMAGE>

Description

"Hazardous Waste Removal System" This invention relates to a system for the removal of hazardous wastes stored in containers.

It is common for hazardous chemical or radiological waste to be placed in containers such as drums which are then stored or dumped. In many cases the containers subsequently become corroded or damaged, often to an extent that attempting to move the container to a safe location for removal of the contents is likely to lead to structural failure of the container and thus escape of the contents.

According to the present invention there is provided a system for removing hazardous waste from a container, the system comprising at least two tool heads one of which is in fluid communication with a source of flushing fluid and the other of which is in fluid communication with a drain vessel for receiving a mixture of flushing fluid and waste; each of the tool heads comprising a member for engaging and sealing with the exterior of said container, and cutting means within the sealing and engagement means for breaching the container to place the interior thereof in sealed communication with the source or drain.

The invention further provides a tool head for use in the foregoing system, the tool head comprising a body, a sealing and engagement member mounted on and projecting from the body, the sealing and engagement member having a front face for engagement with the container and having a central bore, a hollow drill mounted in the body and passing through said central bore, first power means for advancing and retracting the drill with respect to the body, second power means for rotating the drill, and a fluid-tight rotary joint communicating the interior of the drill with a conduit for passage of flushing or waste fluid.

Preferably, the sealing and engagement member is a flexible member.

In an important preferred feature of the invention, the sealing and engagement member is hollow, and means are provided for applying a negative pressure to the interior thereof to cause ambient pressure to force said member against the container.

The first and second power means may suitably be hydraulic or pneumatic.

In a preferred arrangement, four tool heads are mounted on a tool holder, each tool head being pivoted in a yoke formed on a distal end of an arm extending from the tool holder.

From another aspect, the invention provides a method of removing hazardous waste from a container, comprising the steps of: providing a source of a flushing fluid; providing a drain vessel for receiving a mixture of flushing fluid and waste; engaging and sealing first and second tool heads against the exterior of the container; cutting through the container within said tool heads; and establishing fluid communication between said source and said first tool head and between said second tool head and said drain vessel.

An embodiment of the invention will now be described, by way of example only, with reference to the drawings, in which: Fig. 1 is a cross-sectional side view of a tool head used in one embodiment of the invention; Fig. 2 is a plan view of the tool head of Fig. 1; and Fig. 3 schematically illustrates a tool comprising a number of the tool heads mounted on a holder.

Referring first to Figs. 1 and 2, a tool head has an engagement and sealing member 10 having a circular front face 12 formed with concentric ribs 14, a partconical rear face 16, and a central bore 18.

Reinforcing ribs 20 are provided between the front and rear faces 12 and 16.

The engagement and sealing member is mounted by a clamp 22 to the front of a cylindrical body 24 which contains a hydraulic motor 26.

A hollow tubular drill 28 passes centrally through the motor 26 and member 10, the drill 28 suitably being of stainless steel with a diamond faced front cutting edge 28a. The drill 28 is mounted in alignment bearings 30 to be rotated by the hydraulic motor 26, and is also reciprocable in the bearings 30 by a motor driven cam system indicated at 32. The upper end of the drill 28 is connected by a slip joint 36 to a non-rotating hose 38. A seal 39 is provided between the shank of the drill 28 and the bore 18.

The upper part of the tool head is enclosed by a flexible boot 34. Ports 40 in the boot 34 provide a supply and return for the hydraulic motor 26. A further port 42 communicates via a conduit 44 with the interior of the engagement and sealing member 10.

As seen in Fig. 2, the tool head is pivotally mounted on a yoke 46 on an arm 48 along which the various fluid lines pass. Fig. 3 illustrates four such assemblies mounted on a carrier 50 which may, for example, be attached to a robot vehicle for use on land or to a ROV for subsea use.

In use, an assembly such as that of Fig. 3 is brought up to a container of hazardous waste such that the four engagement and sealing members 10 are pressed against the exterior of the container. The form of the members 10 is such that they will seat against flat and curved surfaces likely to be encountered in such use. A negative pressure is then applied to the port 42 causing depressurisation of the interior of the member 10, which in turn causes the ambient pressure to force the face 12 into close engagement with the exterior of the container. The ribs 14 assist in achieving a good seal, providing a pressure gradient across the face 12.

Two of the drill heads are then operated by rotating the drill 28 the motor 26 and advancing the drill by the cam drive 32, until the drill penetrates the container. At this point, actuation of the drills is stopped and a flushing fluid is passed via one of the penetrating drills, through the container, and out through the other penetrating drill. Preferably, the two tool heads used for this purpose are diagonally opposed.

The flushing fluid may simply act as a carrier to remove the hazardous material to a safe location, or may additionally contain a neutralising substance. The flushing fluid exhaust line may pass through an instrument for measuring the presence of the hazardous substance, to assist in determining when the container no longer contains the hazardous substance.

The engagement and sealing member 10 and the shaft seal 39 ensure that during this operation none of the hazardous substance escapes to the environment.

Once the hazardous substance has been cleared from the container, it is safe to move the container even if some mechanical damage occurs by doing so. The container is moved by the tool assembly, with the engagement members 10 providing a sufficient grip for this purpose. The drills 28 may conveniently be left extended to provide enhanced engagement, until the container is landed in a desired location. The drills 28 are then retracted and the members 10 returned to ambient interior pressure to release the container.

The tool head is suitably manufactured with rigid parts in 314 or 316 stainless steel, flexible parts in butyl rubber with PTFE coating, and seals in PTFE.

Modifications may be made to the foregoing embodiment within the scope of the invention as defined in the claims. For example, the tool head may be pneumatic rather than hydraulic, and the drill may be advanced by a pressure ram rather than a motor and cam arrangement.

Claims (12)

1. A system for removing hazardous waste from a container, the system comprising at least two tool heads one of which is in fluid communication with a source of flushing fluid and the other of which is in fluid communication with a drain vessel for receiving a mixture of flushing fluid and waste; each of the tool heads comprising a member for engaging and sealing with the exterior of said container, and cutting means within the sealing and engagement means for breaching the container to place the interior thereof in sealed communication with the source or drain.

2. A system according to claim 1, in which each sealing and engagement member is a flexible member.

3. A system according to claim 1 or claim 2, in which each sealing and engagement member is hollow, and means are provided for applying a negative pressure to the interior thereof to cause ambient pressure to force said member against the container.

4. A tool head for use in the system of claim 1, the tool head comprising a body, a sealing and engagement member mounted on and projecting from the body, the sealing and engagement member having a front face for engagement with the container and having a central bore, a hollow drill mounted in the body and passing through said central bore, first power means for advancing and retracting the drill with respect to the body, second power means for rotating the drill, and a fluid-tight rotary joint communicating the interior of the drill with a conduit for passage of flushing or waste fluid.

5. A tool head according to claim 4, in which the sealing and engagement member is a flexible member.

6. A tool head according to claim 4 or claim 5, in which the sealing and engagement member is hollow, and means are provided for applying a negative pressure to the interior thereof to cause ambient pressure to force said member against the container.

7. A tool head according to any of claims 4 to 6, in which the first and second power means are hydraulic or pneumatic.

8. A tool head substantially as hereinbefore described with reference to the drawings.

9. A system for removing hazardous waste from a container, comprising four tool heads mounted on a tool holder, each tool head being in accordance with any one of claims 4 to 8, each tool head being pivoted in a yoke formed on a distal end of an arm extending from the tool holder.

10. A system for removing hazardous waste from a container, substantially as hereinbefore described with reference to the drawings.

11. A method of removing hazardous waste from a container, comprising the steps of: providing a source of a flushing fluid; providing a drain vessel for receiving a mixture of flushing fluid and waste; engaging and sealing first and second tool heads against the exterior of the container; cutting through the container within said tool heads; and establishing fluid communication between said source and said first tool head and between said second tool head and said drain vessel.

12. A method of removing hazardous waste from a container, substantially as hereinbefore described with reference to the drawings.