WO1996012157A1

WO1996012157A1 - Method and device for the destruction of ammunition

Info

Publication number: WO1996012157A1
Application number: PCT/SE1995/001194
Authority: WO
Inventors: Johnny Ohlsson
Original assignee: Dynasafe Ab
Priority date: 1994-10-17
Filing date: 1995-10-16
Publication date: 1996-04-25
Also published as: SE503731C2; SE9403528D0; SE9403528L

Abstract

The present invention relates to a method and a device for the destruction of ammunition and ammunition components (20) of limited inherent explosive force which are brought to detonation in or on a hot scandbed (13) which causes the initiation and wherein the gases caused by the combustion of the explosive substances are held separate from the gases generated by the heating of the sandbed. The present invention also includes the device designed in accordance with the method described.

Description

METHOD AND DEVICE FOR THE DESTRUCTION OF AMMUNITION

The present invention relates to a method and a device for the destruction of ammunition and ammunition components which have limited inherent explosive force. The invention is conceived mainly for utilization in the destruction of such cartridged ammunition in which the inherent explosive force derives from the explosives and propellant contained in the ammunition. Generally, it can therefore be said that the invention is intended mainly for the destruction of cartridged ammunition from small-arms calibre weapons and up to 30-40 mm, but other ammunition components can of course be destroyed using the invention provided that the explosive force does not exceed the limits imposed by the dimensions of the device.

The basic principle for the method and device in accordance with the present invention is that the ammunition and ammunition components are heated up to combustion, deflagration or detonation while lying on or in a bed of sand which is supplied with heat from an external source, and following the destruction of the said ammunition, this heat is preserved in the sandbed and is therefore an integral part of the process. As the destruction of the ammunition is initiated only by heat energy, large quantities of heat are consumed and this in its turn means that it is important that no heat is wasted unnecessarily.

If the supply of heat for this purpose is carried out using some type of combustion heat such as that supplied by an oil or petroleum gas burner, one must remember that it is considerably easier to carry out separate cleaning and treatment of the fumes from the heat source and those which derive from the combusted explosives and propellant.

Even if the individual ammunition components are of limited size, quite considerable amounts of scrap metal are left following destruction. As there are also large quantities of aged and consequently unreliable ammunition which must be taken care of, it must be possible to operate a destruction process of the type in question more or less continuously with a continuous supply of ammunition components to be destroyed and with the shortest possible interruptions for the removal of the scrap metal formed. The heat losses which take place at the removal of the scrap metal must also be kept to a minimum.

The present invention now offers a practical solution to this problem in accordance with the guidelines stated above.

Destruction of ammunition using the present invention entails the ammunition or ammunition components being heated so as to cause detonation, deflagration or combustion of the explosive substances and propellant in a sandbed inside a chamber adapted for this purpose which also holds the combustion gases formed separate from the fumes generated by the heating process. The chamber used is designed with a circular or multi-cornered section and it is also rotatable around a central axis. The sphere is a specially advantageous form for this purpose as even if it is expensive to manufacture, it is easy to obtain the maximum structural strength with a minimum wall thickness and it is important to have a chamber which withstands a close succession of detonations which individually are of limited force but collectively subject the chamber to considerable stresses. The detonation chamber proposed in the present invention also has an opening in one end of the casing wall which, inside the chamber, is surrounded by a tube which is also designed to withstand the detonations in question. When facing upwards, the opening in the casing wall functions as an inlet for the material to be destroyed and facing downwards, is the outlet for the metal scrap formed in the destruction. A number of compartments are situated in one of the detonation chamber sectors close to the tube and these compartments collect the sand when the scrap metal formed at detonation is emptied out of the chamber. The compartments which together can hold the entire amount of sand for the detonation chamber, consist of a number of partitions which are parallel with the chamber rotation axis and with the main direction of the tube, and which are arranged from the chamber inside wall extending inwards into the chamber while the space between these partitions, ie the compartments themselves are separated from the detonation chamber by a filter which is sufficiently coarse to allow the sand to pass through while retaining at least the major portion of the scrap metal formed at detonation. The tube is also higher along the side turned towards the partitions than along the side opposite. The filter in question is also flat and follows the oblique plane created by the differing heights of the tube edges. The said plane also defines the height of the compartment partitions. The filter is so arranged that the inner opening of the tube is completely free. The advantage of this arrangement is that so long as the tube and compartments are facing upwards, ie so long as the tube functions as an inlet for the ammunition components to be destroyed, the compartments in the upper section of the detonation chamber have no special function but when the scrap metal in the detonation chamber is to be emptied and provided that the detonation chamber has rotated in the direction which results in the part of the filter furthest from the tube making contact with the sand in the sandbed which due to the rotation of the detonation chamber, glides or slides along its inside, all the sand is successively emptied into the compartments while the scrap metal in its turn slides along the filter until it falls through the tube which is now facing downwards and out of the detonation chamber. The rotation necessary for this emptying operation is therefore one half revolution and the tube shall then be facing directly downwards and all the hot sand shall be collected in the compartments the upper sand surface of which is progressively higher the further the compartments are from the outlet and the tube. At the same time, the scrap metal slides out through the tube opening.

By rotating the detonation chamber back one half revolution in the opposite direction to its original position the still hot sand is returned to its original location the only heat loss being that which results from the scrap metal and combustion gases leaving the detonation chamber.

As is clear from the above, the filter is at an angle relative to the tube main direction and it has been found that an angle of approximately 45° functions well. It is clear that it is necessary for the filter to be at a certain angle to the tube in order to facilitate the emptying of scrap metal at the same time as the requirement for sufficiently large compartments for the sand is a decisive factor regarding dimensions.

The present invention is defined in the patent claims below and it is now described in more detail with the help of the enclosed figures. Figs 1, 2 and 3 show longitudinal sections through a device in accordance with the invention in the three different positions: destruction, beginning of emptying of scrap metal, and scrap metal emptying while

Fig 4 shows a cross-section along the line IV-IV in Fig 1.

The device shown in the figures consists of an external furnace 1 which is fitted with a gas or oil burner 2 for heating the furnace 1 and an internal gas outlet 3 for removing the cumbustion gases. Furnace 1 has a gas-tight casing 4 in which a spherical detonation chamber 5 is fixed. The latter can be rotated and is suspended in two pivot axles 6 and 7 which are journalled to the wall of the furnace. The detonation chamber 5 consists of two hemispheres joined along a seam 5a and is of such a robust construction that it can withstand the detonations to be carried out inside the chamber without any problem. In the detonator chamber casing surface there is also an opening 8 which inside the chamber is surrounded by a tube 9 of the same robust construction as the chamber itself. As shown in the figures, the tube 9 is directed axially towards the chamber centre and is also higher on edge 9b than edge 9a. Parallel with the tube edges 9a and 9b and on the latter side of the tube, a number of partitions 10 and 11 are arranged and they extend from the chamber 5 inside up to the level defined by the height of tube edges 9a and 9b. A filter 12 is attached above the tube inner edges and above the partitions upper edges and the filter 12 extends to the inside of the chamber but leaves the tube opening free. The filter has a mesh which allows the sand to run through while retaining the scrap metal formed in the chamber. A sandbed 13 is also located in the chamber.

The furnace wall has an upper inlet 14 with associated gas sluice and gas outlets 15-16 and a lower outlet 17 with gas sluice 18 and gas outlet 19. Gas outlets 16 and 19 are connected to the same extractor in order to retain the fumes formed when burning the explosive substances are burnt.

The figures also show ammunition 20 on the way to destruction and scrap metal 21 formed during destruction and also containers 22 for collecting the scrap metal. A conveyor 23 which delivers the ammunition components is also shown. When the device is in function, the fumes are continually extracted via outlets 3 and 16, 19 and are sent for treatment in accordance with known technology. Ammunition components 20 are delivered via inlet 14 opening 8 and tube 9 to sandbed 13. At the same time, burner 3 provides heat. When a predetermined amount of ammunition is brought to detonation in the furnace it is time to remove the scrap metal and the supply of ammunition is stopped and the chamber 5 is rotated to the position shown on Fig 3.

Fig 2 shows what occurs during the rotation of the furnace. As the rotation takes place in the direction shown on the figures, the compartments between the partitions 10 and 11 first contact the sandbed and this is sieved through the filter and the sand is collected in the compartments while the scrap metal 21 slides along the filter 12 until it reaches the tube 19 opening and drops through into the scrap metal containers 22. The furnace is then turned back in the opposite direction and when in original position, the destruction process can be continued.

Claims

PATENT CLAIMSWe hereby claim and desire to secure by Letters Patent the following.

1. A method of destroying ammunition and ammunition components (20) by detonation and combustion of the explosive substances, propellant and other combustible materials thus formed w h e r e i n the ammunition (20) is brought to detonation, deflagration or combustion by heating on a sandbed (13) in a gas-tight sealed detonation chamber (5) designed to withstand the explosive forces released and w h e r e i n the fumes created in the heating process are held separate from the combustion gases formed at detonation and combustion of the explosive substances, propellant and other combustible components such as plastics included in the ammunition and ammunition components (20).

2. A method as claimed in Claim 1 w h e r e i n the ammunition and ammunition components (20) are continually delivered to a hot sandbed (13) for destruction during the simultaneous supply of heat in sufficient quantities to bring the explosive substances and propellant in the said ammunition and ammunition components (20) to detonation, deflagration or combustion. The supply of ammunition and ammunition components is interrupted when it is time to empty the scrap metal (21) formed in the detonation chamber whereby the sandbed (13) is fed into the compartments in the detonation chamber for this purpose. Due to its greater particle size the scrap metal (21) does not enter these compartments but is emptied from the detonation chamber (5)upon which the sandbed (13) is returned to its original position and the procedure can be continued.

3. Method as claimed in Claim 2 w h e r e i n a detonation chamber (5) which can be rotated around a central axis (6, 7) with circular or multi-cornered section and with an opening (8) which when facing upwards functions as an inlet for ammunition and ammunition components (20) which are to be destroyed and which when facing downwards functions as an outlet for the scrap metal (21) which is to be recovered, functions as a detonation chamber.

4. Device for the destruction of ammunition and ammunition components (20) by detonation, deflagration or combustion of the explosives, propellant and other combustible materials contained and the recovery of the scrap metal (21) thereby formed in accordance with the method as claimed in any of Claims 1-3 w h e r e i n a detonation and combustion chamber (5) which is rotatable round a central axis (6, 7) is incorporated. The detonation chamber (5) is heated externally and the combustion gases formed during heating are screened off from the detonation chamber (5) The said detonation chamber (5) has a circular or multi-cornered section with an opening (8) made in the chamber wall which when facing upwards functions as an inlet and when facing downwards functions as an outlet. The opening is surrounded by a tube (9) which is angled towards the centre of the chamber. A number of partitions (10, 11) are arranged in the sectors to one side of the tube and the said partitions (10, 11) are parallel with the chamber rotation axis and with the tube main direction and extend from the chamber (5) wall inwards into the chamber (5). The said partitions form a number of spaces or compartments which are separated from the rest of the chamber (5) by a filter (12) fixed to the free edges of the partitions. The filter has a mesh size which prevents the passage of most of the scrap metal formed in the chamber but leaves the tube (9) opening entirely free. The detonation chamber (5) contains a quantity of sand (13) which can be contained in the said compartments and has a particle size that enables passage through the filter (12).

5. Device as claimed in Claim 4 w h e r e i n the detonation and combustion chamber (5) is of spherical form.

6. Device as claimed in Claim 5 w h e re i n the detonation and combustion chamber (5) is sealed in a gas-tight casing (4) in a furnace (1) for heating the detonation and combustion chamber (5). The furnace (1) has its own fume outlet and the chamber (5) and the casing (4) are fitted with a common gas outlet (16, 19) for the combustion gases released at destruction.

7. Device as claimed in Claim 6 w h e re i n an upper inlet (14) runs through the furnace (1) and chamber's gas-tight casing (4) and a lower outlet (17) to which the chamber opening (8) can be connected by rotating round its own axis (6, 7).

8. Device as claimed in Claim 7 wherein both the inlet (14) and outlet (17) are fitted with gas sluices (16, 19) for the retention of the combustion gases.

9. Device as claimed in any of Claims 4-7 wherein the side (9b) of tube (9) facing the compartments is higher than the opposite side and the compartment partitions (10, 11) are of a height that enables a filter (12) fixed to partition (10, 11) free edges to incline evenly towards the tube lower edge (9a).