DESTRUCTION ARRANGEMENT

Abstract: The present invention relates to an arrangement for destruction of ammunition and ammunition components and conversion of these goods for destruction to metal scrap prepared for re-use. The invention is based on the goods for destruction being introduced into a destruction chamber (6) designed in a special manner, in which the goods are heated to a temperature which causes the explosive substances included therein to be combusted, to detonate or to deflagrate. The heating is carried out by burners (4) arranged outside the chamber, and scrap (22) from previously destroyed goods which has remained in the destruction chamber (6) serves as a heat accumulator for retaining heat liberated during the destruction of the explosive goods. A characteristic feature of the destruction chamber (6) is that it has the shape of a double cone (9, 10) with a short cylindrical intermediate part (11) between the base edges of the cone parts. The advantages of the present construction include the fact that the special shape of the destruction chamber makes it relatively easy to manufacture at the same time as it contributes actively to adequately high temperatures being achieved inside the same in order to give a good handling capacity.

Description: DESTRUCTION ARRANGEMENT The present invention relates to an improved arrangement for destruction of ammunition and ammunition components with limited inherent explosive force inside a detonation-proof chamber intended for this, which on the one hand screens the destruction process from the environment and on the other hand makes it possible separately to retain and clean the explosion gases formed during the combustion, deflagration and/or detonation of the explosive substances included in the goods for destruction. The destruction process itself is based on the explosive substances included in the goods for destruction being, by indirect heating, provided with a sufficiently high temperature in order to be combusted, to detonate or to deflagrate. An earlier arrangement for destruction of the same type of products, which works in accordance with corresponding basic principles, is described per se in our own Swedish Patent Application 9403528-4. The need for this particular type of arrangement can be expected to increase considerably in the coming years because great quantities of small-calibre and medium- calibre ammunition manufactured during the very coldest years of the cold war are approaching the end of their life at the same time as previously used methods of disposing of such products by dumping them in the sea, mineshafts or deep lakes have become entirely unacceptable for environmental reasons. These products also contain great quantities of valuable metals which it can be quite important to retain. In order to meet future requirements, a destruction arrangement of this particular type must be robust and capable of being manufactured at as low a price as possible at the same time as it is a significant advantage if it can be made mobile and can easily be transported to the place where the ammunition is located so that transporting old, unsafe ammunition over long distances is avoided. Our own Swedish Patent Application 9403528-4 mentioned above describes an arrangement which fulfils some of these requirements but at the same time has a number of disadvantages, mainly as far as the costs of manufacturing the arrangement in question and the capacity of the arrangement itself are concerned, and the object of the present invention is to provide an arrangement which in part works on the same principles as but does not have the disadvantages of that according to SE 9403528-4. The arrangement according to SE 9403528-4 thus describes a destruction arrangement for treatment i.e. destruction of ammunition and ammunition components with limited inherent explosive force, which in principle concerns ammunition up to approximately 60 mm calibre. The arrangement in question comprises a ball-shaped inner detonation or destruction chamber which is dimensioned so as to stand up to the detonations which the goods which are to be destroyed in the same might give rise to. The detonation chamber is in turn rotatably arranged inside a heat-insulated outer chamber, in which burners for external heating of the detonation chamber are also arranged. Inside the chamber, a sand layer is then arranged, which, through the external heating of the chamber together with the radiant heat, rapidly provides the ammunition components introduced into the chamber with such a high temperature that explosive substances included in them are ignited and combusted, detonated or deflagrated. The advantages of the sand layer are firstly that the heat transfer to the ammunition components introduced is very effective and also that it functions as a heat accumulator and retains and stores the heat which is formed during the combustion, detonation or deflagration of the explosive substances in question. The arrangement according to this construction is, however, expensive to manufacture, on the one hand because the ball-shaped chamber is itself difficult to manufacture and requires a great deal of work, and on the other hand because the chamber requires certain equipment which is described in greater detail in the patent specification. This in fact makes it possible in principle simply to empty out the scrap formed during the destruction and keep the hot sand inside the chamber. For emptying the chamber, use is made of the previously mentioned possibility of rotating the chamber, which means that an upwardly facing filling opening is transformed, after a 180° rotation, into an emptying outlet . At the same time as the sand layer therefore has a number of advantages, it also has the disadvantage that it takes up space and therefore increases the requirement for available chamber volume at the same time as the previously mentioned chamber equipment, which makes it possible to empty the scrap out of the chamber but keep the sand, is expensive to manufacture on the one hand and on the other hand restricts the life of the chamber because it is not possible to avoid it being gradually damaged. These disadvantages led us to perceive the need to improve our arrangement . The aim of the present invention is to provide an arrangement which can solve the same problem as our earlier ammunition destruction arrangement described in the abovementioned patent application but which can be manufactured at a considerably lower cost. This has been made possible because we have found that if we provide the inner detonation chamber with a special shape, which can most closely be described as a double pyramid, or even better a double cone, instead of the previous ball-shape, we obtain a chamber which, at least in the case of the double-cone shape, has a strength and capacity to stand up to inner detonations which do not fall far short of the previously used ball-shape, at the same time as the chamber is considerably easier and less expensive to manufacture. A further advantage which this basic shape provides is that the chamber volume in the downwardly facing tip of such a chamber is very concentrated and we have now been able to establish that, thanks to the very good heat transfer obtained in this case in this part of the chamber via radiant heat and via direct transfer through the chamber wall, we can provide the goods for destruction inside the chamber with the high temperature which is required for ignition of all types of explosive substances which may be involved. With this type of chamber, it has therefore been possible for us completely to dispose of the sand layer and the chamber equipment previously necessary for its maintenance. When the destruction process is then m full-scale operation inside the chamber, the gradually formed scrap layer then takes on the role of the sand as heat accumulator. With an arrangement according to the present invention, it has therefore been possible to maintain a corresponding destruction capacity but in a smaller and less expensive arrangement. The arrangement according to the invention has been defined in the following patent claims and will now be described in somewhat greater detail together with the attached figures which, however, represent only an example of the invention, and m which Fig. 1 shows a sectioned longitudinal projection with the inner destruction chamber in the filling/destruction position, Fig. 2 shows a sectioned lateral projection of Fig. 1 along the line I-I, and Fig. 3 shows the same projection as Fig. 2 but with the inner destruction chamber m the emptying position. The references in the various figures consequently correspond fully with one another. The destruction arrangement according to the invention thus comprises a heat-insulated outer chamber 1 suspended m a stand 2 which is only drawn in part in the figures. The outer chamber 1 can be rotated about the horizontal axis 3 by means of rollers fixed m the stand which are not shown in the figures. Arranged in the wall of the chamber is a burner 4 for heating the interior of the chamber and the inner destruction chamber 6 suspended therein. In the wall of the outer chamber, there is also a gas outlet 5 for the combustion gases generated in the oil or LPG burner 4. In the wall of the outer chamber 1, there is also a combined inlet/outlet opening 7 for the chamber 6. We will return to this further on. An important point which may be mentioned now, however, is that the opening 7 with its respective side walls, together with a fixing point 8 arranged on the opposite side of the chamber, constitute the suspension points for the inner chamber 6 in the outer chamber 1. The inner destruction chamber 6 has the shape of two identical frustocomcal gable pieces 9 and 10 which face away from one another with their tapering parts and which between them have a cylindrical intermediate part 11 For purely practical reasons, however, the chamber is constructed in two parts which are joined together with one another. The dividing line between them runs along tne line 12 along a central dividing plane through the cylindrical part The joining-together between the parts has, as shown in the figures, been effected by means of flanges arranged on the parts and a joint band 15 holding tne flanges 13 and 14 together This basic shape gives the inner detonation chamber 6 great resistance to internal detonations but is at the same time relatively easy to manufacture and it is or parts of it are therefore easy to replace. The stresses are m fact very great on a destruction chamber of this type and it is therefore essential to be ready to replace the same after a relatively long period of continuous operation. As can be seen from the figures, there is also a separate gas outlet 16 for the explosion gases formed inside the chamber during the combustion of the explosive substances. These are in fact intended to be taken for separate advanced cleaning while the combustion gases removed through the gas outlet 5 can be subjected to simpler cleaning. The previously mentioned inlet/outlet 7 consists of a first pass-through part 17 in which an openable and closable detonation closing hatch or lock hatch 18 is arranged. Detachably connected to this pass-through part is a second lock part 19. The latter part comprises a second openable and closable closing hatch 20 and also a container 21 designed for goods for destruction in a suitably adapted quantity. These parts 19-21 form part of the feed system, the destruction chamber 6 being supplied batchwise with ammunition and ammunition components in a quantity adapted to the quantity of explosive substance which the destruction chamber stands up to with a good margin. The feed system does not, however, directly constitute a part of the invention and for this reason no further details have been included in the figures The basic principle, however, is that the lock part 19 with the filled container 21, and with the hatch 20 closed, is connected to the pass-through part 17, after which the hatches 20 and 18 are opened and the goods for destruction are introduced into the interior of the destruction chamber 6. In the respective figures, there is also a scrap bed 22 formed in the chamber 6. In the chamber 6, there is also an edge wall 24 arranged on one side of its combined inlet/outlet opening 23. We will return to this further on in the text. In the figures, there is also a scrap box 25 for collecting scrap emptied out of the destruction chamber. The space 28 is a scrap box. The general functioning cycle of the arrangement is as follows . The ammunition components which are to be destroyed are introduced into the destruction chamber 6 batchwise from container 21 at a rate adapted to the material and the capacity of the arrangement. At the same time, the burner 4 acts on the outside of the chamber 6. Explosive substances included in the ammunition components are combusted, detonated or deflagrated and metal parts involved gradually form a broken-up scrap. This forms a scrap layer in the interior of the chamber 6 which, as it grows, becomes an increasingly effective heat accumulator for all the heat which is formed during combustion of the explosive substances. The supply of external heat is therefore adjusted according to the need to heat the chamber. When the quantity of scrap in the chamber has become so great that emptying is necessary, the introduction of new ammunition components is interrupted and the outer chamber 1 is rotated through 180° so that the opening 23 of the inner chamber 6 faces downwards and the scrap is emptied into the scrap box 25. If in this connection the rotation takes place in the direction which means that the edge wall 24 as it were lies in front of the opening during rotation, some of the scrap will remain in the chamber in the manner shown in Figure 3. In this way, there is also a scrap bed to begin with. If rotation takes place in the opposite direction, the chamber is emptied completely. In this connection, it is also appropriate to mention the protection plates 26 and 27 which ensure that scrap does not begin to fall out of the chamber at too early a stage and which furthermore guide the scrap towards the scrap box 25.

Claims: PATENT CLAIMS 1. Arrangement for destruction of ammunition and ammunition components and conversion of these goods for destruction to metal scrap prepared for re-use by combustion, detonation or deflagration of explosive substances included therein initiated by heating the goods for destruction to a temperature corresponding to the ignition temperature of the explosive substances, comprising an externally heated detonation chamber (6) which is rotatable about a horizontal axis, is provided with a single opening (7) which functions as inlet and outlet respectively depending on the position set, and is dimensioned so as to stand up to repeated detonations corresponding to the maximum explosive force of the goods which are to be destroyed, characterized in that the destruction chamber (6) essentially has the shape of a double pyramid or double cone (9, 10) with the axis of rotation through the plane in which the pyramids or cones meet and with its opening (7) at the top of one (9) of these pyramids or cones, the chamber (6) also having an outlet (16) for the explosion gases formed during the destruction of the explosive substances. 2. Arrangement according to Claim 1, characterized in that the destruction chamber (6) has the shape of two frustoconical gable parts (9, 10) arranged with their bases facing one another, with a cylindrical intermediate part (11) arranged between these parts and with one frustoconical part ending in said opening (7) and the other in a smaller plane outer gable end. 3. Arrangement according to Claim 1 or 2, characterized in that the destruction chamber (6) is suspended in a heat-insulated outer chamber (1) , the interior of which and with it the exterior of the destruction chamber also can be heated by burners (4) intended for this, the outer chamber (1) in turn being rotatable about a horizontal axis (3) so that the destruction chamber (6) can assume either a first filling/destruction position, with its opening (7) facing upwards and itself having an inlet provided with a detonation lock (17, 18) , or facing downwards towards an outlet (26, 27) . 4. Arrangement according to one of Claims 1-3, characterized in that the destruction chamber has on the inside on one side of its opening a screen (24) which, in conjunction with emptying of the chamber, will retain some of the scrap in the chamber provided that the chamber is rotated towards the emptying opening in the direction which means that the edge of its opening (7) provided with the screen (24) reaches the emptying opening before the other parts of the chamber opening. 5. Arrangement according to Claim 3 or 4, characterized in that the detonation lock (7, 17, 18) comprises two openable and closable hatches (18, 20) which are connected together with one another in such a manner that only one hatch can be opened at a time. 6. Arrangement according to Claim 4, characterized in that goods which are to be destroyed are supplied to the detonation lock by a batch-feeding arrangement (19- 21) , the inner volume (21) of which corresponds to the quantity of goods for destruction which the inner chamber is expected to stand up to at one time.

Inventors: OHLSON JOHNNY, OHLSON, JOHNNY
Applicants: DYNASAFE AB, OHLSON JOHNNY, OHLSON, JOHNNY
Application year: 1997
Main classification: F42D5
IPC codes: F42B33