GB2579091A

GB2579091A - Tool

Info

Publication number: GB2579091A
Application number: GB1818907.6A
Authority: GB
Inventors: Winslow John
Original assignee: Disarmco Holdings Ltd
Current assignee: Disarmco Holdings Ltd
Priority date: 2018-11-20
Filing date: 2018-11-20
Publication date: 2020-06-10
Anticipated expiration: 2038-11-20
Also published as: GB201818907D0; GB2579091B

Abstract

A method of removing explosive material from a previously opened shell casing 10 involves the steps of gripping the shell in a holder and inserting a tool 14 into the explosive material 11 through a hole in the shell casing 10. The tool 14 and shell casing 10 are moved relative to one another to dislodge explosive material 11 from the casing. The tool 14 is heated to above the melting point of the explosive material 11.

Description

-1 -TOOL

Field of the Invention

The present invention relates to the removal of explosive material contained within a previously opened shell of a munition, so that it may be safely removed and disposed of.

Background of the Invention

It has previously been proposed to cut through the shell of a munition in order that its contents may be removed. One known method is to cut through the munition at its point of maximum girth using either a metal cutting implement or a water jet.

Even when a metal cutting implement is used, the implement is normally lubricated with water and inevitably water comes into contact with the explosive material during the course of opening thc shell and the water becomes contaminated.

Water that is contaminated with explosive material, referred to as pink water, cannot safely be allowed to flow into drains or into nearby rivers and itself presents a disposal problem.

DE 42 21 666 and FR 2894660, amongst other prior publications, disclose a method of opening a munition that involves partially cutting through the shell of the munition to leave a very thin residual wall thickness and then applying shearing or bending forces to perform the final separation to crack open the shell of the munition.

DE 42 21 666 uses a water jet to cut a groove in the munition. If the water jet is directed radially, the depth of the cut made by the water jet cannot readily be determined. Instead, -2 -therefore, DE 42 21 666 aims the jet tangentially, as illustrated in Figure 1 of the patent.

FR 2894660 additionally proposes machining or using a laser 5 but regardless of the method used to cut a groove in the wall of the munition it is difficult to penetrate the wall of the munition to leave behind a uniform thickness of metal.

The above and other methods result in an open munition containing an exposed amount of high explosive. The subsequent removal of the high explosive, in order to render the munition safe, presents further challenges both in terms of safety, but also safeguarding the environment from contamination.

Object of the Invention The present invention seeks therefore to provide a method and apparatus for rcmoving high cxplosivcs from an opcn munition shell casing without creating pink water and without risking the creation of sparks that may potentially detonate the explosive material contained within the shell.

Summary of the Invention

According to a first aspect of the present invention, there is provided a method of removing explosive material from within a previously opened shell casing, the method comprising: gripping the opened casing in a holder; inserting a tool into the explosive material through an opening created by the opening of the shell casing; and moving the tool and shell casing relative to one another in order to dislodge the high explosive from the casing, characterised by heating the tool to above the melting point of the explosive.

According to a second aspect of the present invention, there is provided a tool for removing explosive material from within a previously opened shell casing comprising: a shaft; a cutting head at one axial end of the shaft; a shank at the other axial end of the shaft to enable the tool to be retained in a holder, characterised in that the tool incorporates a heating feature for enabling the tool to be heated to a temperature greater than the melting point of the explosive material.

Brief Description of the Drawings

Figure 1 shows a section view of the invention; and Figure 2 shows a section view of the invention in a plane perpendicular to that of figure 1.

Detailed Description of the Drawings

Figure 1 shows a section view of an apparatus for removing from a shell casing 10 a high explosive material 11 such as TNT (Trinitrotoluene) or RDX (cyclotrimothylonctrinitramino). The apparatus comprises includes a shell holder 12; a tool 14; and a receptacle 16 for catching any explosive 11 removed by the tool 14.

The shell holder 12 acts as a clamp to hold the previously opened shell casing 10 securely, the holder 12 having at least two (but preferably three) separate jaws to receive a shell 10 of circular cross section. The jaws grip the surface of the opened shell casing about its circumference in a similar way to a chuck gripping a drill bit.

The holder 12 may be machined or treated to improve the grip of the holder 12 on the shell casing 10. The holder 12 may, for example, be knurled, contain protrusions, or include a roughened surface to provide more friction. Like a chuck, the holder 12 may have an adjustable diameter to receive any diameter of shell casing 10 between 100 millimetres and 160 millimetres. Inserts (not shown) may be used to reduce the diameter of the shell casing 10 which may be held in the holder 12, and the inserts may also include friction improving features. The diameter of the holder 12 may be adjusted mechanically, pneumatically, hydraulically or electronically. The holder 12 is preferably rotatable about the major axis of the shell casing 10.

The tool 14 of the present invention is substantially cylindrical in shape and should be longer than the shell casing 10 with which it is to be used. The tool 14 comprises a cutting tip 22 at an end proximal to the high explosive 11 within the shell casing 10 and a shank 20 at a distal end. A shaft 24 extends between the two ends of the tool, and may feature one or more flutes 26 in its surface, extending at least partially from the cutting tip 22 towards the shank 20. The one or more flutes 26 may be helical.

The shank 20 may be of any type commonly used in tool holding. Thc cutting tip 22 may bc dctachablc and rcplaccablc, and features at least one cutting edge 26. It may be manufactured from a material different from that of the shaft 24 and the shank 20. The tip 22 is preferably manufactured from a material, such as a plastics material, that has a low thermal conductivity and does not present a risk of sparking if it should contact the shell casing. Alternatively, the tip 22 of the tool 14 may be manufactured from the same material as the shaft 24 and the shank 20, and be coated with a different material. To further reduce the risk of sparking between the shaft 24 and the shell casing 10, the cutting tip may preferably be of greater diameter than the shaft.

At least the shaft 24 incorporates a heating feature to ensure that no explosive 11 remains adhered to the tool 14, as this could risk safety and be an environmental hazard. In use, the tool 14 is heated to above the melting point of the explosive 11, and preferably to approximately 90°C. The heating feature of the tool 14 may comprise an electric heating element, such as to be found in water heating kettles, or one incorporating -5 -a PTC resistor. Alternatively, as shown in the embodiment of Figure 1, the heating feature may be formed by internal channels 14 that allow a heating fluid, preferably a liquid, to flow through the tool.

The internal channels 14 allow circulation of liquid inside a closed system, which comprises a remote heating mechanism (not shown). This advantageously allows careful control of the temperature, without risk of ignition of the explosive 11.

Furthermore, as the circulation system is closed, there is no the risk of the heating fluid being contaminated by the explosive 11.

A tool holder (not shown) is provided to grip the shank 20 of the tool 14. The tool holder is supported by and connected to the end of a moveable arm 32. The arm is in turn covered by a shroud 34, to deflect any explosive 11 falling from the shell casing 10. Thc arm 32 is preferably movcablc by translation but may also be tilted. The arm movements may be controlled mechanically, pneumatically, hydraulically, electronically or a combination thereof. In cross section, the shroud 34 is triangular or arrowhead shaped, as shown in Figure 2. As the upward facing surfaces are steeply incline, no explosive 11 can settle or pool on the shroud 34 and instead falls or is deflected into the receptacle 16.

The tool 14 can be inserted into the tool holder through an orifice 40 in the top of the shroud 34, the orifice 40 being only very slightly larger than the diameter of the shank 20.

The orifice 40 has an annular seal 36 to avoid any explosive material 11 becoming trapped under the shroud 34. Pipes 38 carry the flow and return of the heated fluid to and from the channels in the tool 14, the pipes 36 being arranged under the shroud 34 to protect them from the explosive 11.

In an embodiment of the invention where the tool may spin, a sealed ring 42 with an annular channel is provided, to allow -6 -rotation of the tool while maintain fluid connection to the integral channel.

The receptacle 16, fixable to the arm 32 or any other part of 5 the apparatus, is suitably Large to ensure that all explosive material 11 is caught. The base of the receptacle 16 may be inclined towards a lower surface which features at least one hole. Explosive material 11 removed from the shell casing then drains into a transport receptacle 18. The transport 10 receptacle 18 is simple in shape and easily removed from the apparatus for cleaning and subsequent disposal of the high explosive 11 removed from the shell casing 10.

A method of removing high explosive 11 using the apparatus 15 described above will now be described, by way of example.

Once the shell casing 10 has been opened by any method known in thc art, it is grippcd in thc shc11 holdcr 12.

The removal of the high explosive 11 may differ, depending on, for example, preference of the operator or the type of explosive 11 to be removed from the casing 10.

One method comprises rotating the shell casing 13, moving the tool 14 axially to come into contact with the explosive 11, and then moving the tool 14 radially. This would cause a layer of explosive 11 to be dislodged from the shell casing 10. Once one layer has been removed, the procedure is repeated until the shell casing 10 is substantially empty. In this embodiment, the at least one flute 26 promotes the high explosive 11, for example TNT, to remain in contact with the tool 14 and directs the high explosive 11 toward the shank 20 end of the tool in a controlled manner following the path of the flute 26, where it is collected in a receptacle 16. -7 -

The heating of the tool serves to melt any explosive 11 that sticks to the tool such that it drips down into the receptacle 16.

Another method comprises rotating the shell casing 10 and then moving the tool 14 axially, and at a radius near to that of the casing 10 diameter, at a controlled rate until the tool 14 has penetrated the explosive 11 to the depth of the shell casing 10. As the shell casing 10 is rotating, this method would release the explosive 11 from the casing 10 and allow it to fall into the receptacle 16.

It will be apparent to those skilled in the art that the methods disclosed above are not the only methods of carrying out the invention and that other variations exist, such as moving the tool 14 from the centre to outer edge of the casing 10 or vice versa, or the tool 14 may rotate. Moreover, it is not necessary that any part of the system rotates (as shown by arrows d and e in Figure 1) or tilts (arrow c and g); the tool 14 may dislodge the explosive 11 from the shell casing 10 through translation (a, b and optionally f) alone. -8 -

Claims

CLAIMS1. A method of removing explosive material from within a previously opened shell casing, the method comprising: gripping the opened casing in a holder; inserting a tool into the explosive material through an opening created by the opening of the shell casing; and moving the tool and shell casing relative to one another in order to dislodge the high explosive from the casing, characterised by heating the tool to above the melting point of the explosive.
2. The method of Claim 1, wherein the casing and tool are rotated relative to one another.
3. The method of Claim 2, wherein the casing is rotated about its major axis while the tool is held stationery.
4. The method of any preceding claim, wherein the step of inserting the tool into the casing comprises advancing the tool toward the shell casing in the direction of the axis of the casing.
5. The method of any preceding claim, wherein the tool is heated by means of a liquid flowing through a fluid channel within the tool.
6. The method of Claims 1 to 4, wherein the tool is heated by means of an electrical element.
7. The method of any preceding claim, wherein the tool is heated to approximately 90 degrees Celsius.
8. A tool for removing explosive material from within a previously opened shell casing comprising: a shaft; a cutting head at one axial end of the shaft; and a shank at the other axial end of the shaft to enable the tool to be retained in a holder, characterised in that the tool incorporates a heating feature for enabling the tool to be heated to a temperature greater than the melting point of the explosive material.
9. The tool of Claim 8, wherein the heating feature comprises a channel having an inlet and outlet through which heated fluid flows.
10. The tool of claim 9, wherein the channel is internal to the tool.
11. The tool of claim 8, wherein the heating feature is an electrical element.
12. The tool of claims 8 to 11, wherein the shaft is helically fluted, to guide removed explosive material along the shaft, for controlled release into a receptacle below.