FI67838C - SMAELTKAERL FOER SPRAENGAEMNE - Google Patents

Description

ΓΓ7ϋΖ ~ 1 r „,, ANNOUNCEMENT„ „Β 11> UTLÄGGNINGSSKRIFT 6 7838 · | Μ C <45> Pat '••' it csddeiat (51) Kv.lk.4 / lnt.CI. * C 06 Β 21/00 (21) Patent application - Patentansöknlng 791795 (22) Application date - Ansökningsdag 05-06-79 (Fl) (23) Starting date - Giltighetsdag 05-06.79 (41) Published public - Blivit offentlig 06.12.79

National Board of Patents and Registration (44) Date of publication and date of publication. _

Patent- och registerstyrelsen '1 Ansökan utlagd och utl.skriften publicerad 2ö.U2.o5 (32) (33) (31) Requested Privilege — Begärd Priority 05.06.78

German Federal Republic of Germany (DE) P 2824591-2 (71) Wasag-Chemie A.G., Miinchener Strasse 70, 8043 Unterfoehring,

Federal Republic of Germany FÖrbundsrepubliken Tyskland (DE) (72) Helmut Wagner, Essen, Manfred Schaefers, Bottrop, Federal Republic of Germany Förbundsrepubl iken Tyskland (DE) (74) Oy Kolster Ab (54) Explosive smelting boiler

The invention relates to a melting boiler in the interior of which a propeller mixer is arranged and in which a side wall and possibly a bottom consisting of a smooth outer jacket and an inner jacket have cavities for the flow of heating medium, by means of which the indoor explosive melt can be indirectly tempered.

Such a melting boiler operates to produce a molten explosive at a casting temperature. The explosive is further processed from the melting boiler by draining, for example, into the projectiles. In order to charge the melting boiler, at least partially already melted explosive is used, which has been melted in another, pre-connected device. Optionally, a solid explosive is added to the melting pot, e.g. in the form of granules, flakes or pieces, which merges with the melt in the melting pot. The explosive melt thus formed is brought by lowering the temperature to a casting temperature which has a very small tolerance to the solidification temperature of the melt, in which case already 1-2 ° C are critical. The heat required to melt the added solid explosive is introduced at least in part by means of a heating medium which is otherwise responsible for the general temp of the melting boiler.

Safety regulations require that there are no separate heating elements inside the equipment for defrosting and tempering the explosive. In addition, the tempering takes place indirectly in the side wall and possibly also through the cavities in the bottom. In addition, safety regulations limit the maximum difference between the temperature of the heating medium and the melting temperature of the explosive to a relatively low value of only a few degrees Celsius. This, together with the generally smooth side walls inside known melting boilers, limits the melting efficiency of the boiler. In addition, rapid adjustment of the explosive melt to the casting temperature by means of the heating medium is not possible.

The "Uddeholm thermochannels" brochure are known as double-walled structural elements for conducting a heating or cooling medium. Both walls of the structural elements are slightly corrugated, the waves being displaced relative to each other and the walls being welded together. Due to the suitable shape and distribution of the structural elements, the medium flows tortuously in them, see Figure 1 of the brochure, and in this case the medium flows mainly transversely against the corrugation of the wall, i. horizontally in Figure 1. Figures 7-9 and 14 and 15 of the brochure actually show a container, the side walls of which are formed of such structural elements and which then have cavities for the flow of heating medium. The individual structural elements are connected to each other by welding, see page 7, last paragraph. Due to the structure of the structural elements described above, no channels are provided in the side walls for the heating medium in this connection, which would pass vertically through the side walls. In contrast, the heating medium is conducted in the side walls mainly in the circumferential direction, which corresponds to the winding path of the individual structural elements. In this context, the heating medium must travel long distances between the inlet and the outlet.

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Although the explosives industry is listed on page 1 of the brochure as an area of use for structural elements, this use is reversed in cases where the structural elements come into direct contact with explosives because the structural elements have welds and the structural elements can only be joined together by welding. However, welding joints are outright prohibited due to the safety risk of all equipment that comes into direct contact with explosives. Another problem in the planned use of structural elements for the construction of an explosive smelting boiler is the long distances that the heating medium must travel between the inlet and the outlet. These long distances cause a relatively large temperature gradient in the heating medium, which is incompatible with the need to keep the casting temperature variations of the explosive melt very small.

Accordingly, it is an object of the invention to design a melting boiler of the type mentioned at the beginning so that a high melting efficiency is achieved while maintaining safety regulations and rapid adjustment of the explosive melt to the casting temperature.

This object is solved according to the invention in that each propeller shaft of the agitator is located vertically and that the inner jacket of the side wall is folded in the circumferential direction into the form of perpendicular ribs advancing in a circumferential manner, delimiting a separate channel for the heating medium.

In the smelting boiler according to the invention, the ribs cause a considerable increase in the surface through which the explosive can participate in the heat exchange by means of the heating medium.

This also makes it possible to introduce or remove relatively large amounts of heat to the melt in a short time in connection with small temperature differences between the heating medium and the explosive melt. This results in high melting power and rapid adjustment of the explosive melt to a predetermined temperature of the heating medium. Sweden still has the advantageous effect of acting as "breakwaters" with respect to the explosive melt rotated by the mixer, thus ensuring very thorough and very rapid mixing of the melt in all its parts. Given the poor thermal conductivity of the explosive, this also contributes to the rapid heat transfer between the explosive melt and the heating medium. In addition, a very even temperature distribution in the explosive melt is guaranteed without the formation of significant temperature gradients even in the vicinity of the side wall. Finally, it is possible to actively, rapidly cool the explosive melt to the casting temperature by means of a heating medium, which in this case acts as a cooling medium compared to the melt, without the risk of scale formation on the side walls of the melting boiler caused by the solidified explosive. Compared to the natural cooling used so far, the time required to reach the casting temperature is thus greatly reduced, e.g. from two hours to 10-15 minutes. Finally, with the appropriate melting boiler temperature control, it is still possible to keep the clean, crystallizing explosive melt at the casting temperature for several hours without any temperature-induced changes in the melt. Further processing of the melt can thus be easily extended to a longer time.

Suitably, the ribs in each case limit the heating medium of the separate channel, because then the homogeneity of the heat transfer between the heating medium and the explosive melt is further increased.

In a preferred embodiment of the new melting boiler, the folded inner jacket has its outward corrugated peaks against the outer jacket. With this solution, the manufacture of a new melting boiler is particularly simple. In addition, a particularly large inner surface is obtained compared to the outer surface of the side wall, which is of course advantageous for the heat transfer rate.

Particularly in terms of acting as "breakwaters", it has proven advantageous if the ribs have a triangular cross-section. In addition, of course, other cross-sectional shapes are possible, e.g. a semicircular cross-section.

The smelting boiler according to the invention is intended in particular for the treatment of trotyl or toryyl and hexogen, mixtures of trotyyl and ammonium nitrate or trotyl / hexogen / aluminum.

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In the following, the invention will be explained in more detail with its other advantageous details in connection with a schematically shown embodiment. In the drawing: Fig. 1 shows a schematic view of an apparatus for melting an explosive comprising a melting boiler according to the invention, Fig. 2 a vertical section of the melting boiler of Fig. 1 with the lid removed, Fig. 3 a section along line 3-3 of Fig. 2;

According to Figure 1, an apparatus for melting TNT comprises a device 1 for rapidly melting imported TNT in solid form, comprising a heated collection tank 2 for molten TNT. From here, the molten TNT is fed in a permissible range to a weighing device 3 heated at a temperature above the melting point, which is connected to the collecting tank 2 via a heated outlet pipe 4. A certain amount of molten TNT enters the melting device 3 through the heated pipe 5 to the melting boiler 6. Several similar melting boilers can be connected to the weighing device 3.

Only 20-40% of the maximum boiler volume of the melting boiler 6 is filled with castable TNT melt. The rest of the TNT is then added in solid form, e.g. as granules. This part is converted into melt in the melting boiler 6. Inside the melting boiler 7 there is a mixer 8, which is driven by a motor 10 arranged on the melting boiler cover 9 and which continuously rotates the TNT melt.

The circular melting boiler 6 is heated indirectly from its side wall 11 and bottom 12 by means of a heating medium, e.g. water. The melting heat for TNT added in solid form is taken not only from the heating medium, but also from the TNT in the boiler, heated above the melting temperature, which thus drops the temperature. The remaining temperature-difference from the casting temperature is then removed by cooling with a heating medium, which in this case, compared to the TNT melt, is used as a cooling medium. The TNT melt thus brought to the casting temperature of 6 67838 and subsequently maintained at the casting temperature is passed through a heated outlet pipe 13, e.g. to TNT-filled projectiles.

Figures 2 and 3 show the details of the entirely stainless steel smelting boiler 6. The side wall 11 consists of a smooth, cylindrical outer jacket 14 and an inner jacket 15 which is continuously folded in the circumferential direction into a triangular wave shape and the outer formed a plurality of similar, hollow ribs 17, each of which has a triangular cross-section and which run axially or vertically, point towards the interior 7 of the melting boiler 6 and delimit a separate vertical channel 18 for the heating medium in each case.

The bottom 12, which slopes slightly downwards towards the center, has an annular channel 19 on the outside at the circumferential edge, which communicates with each channel 18 via the bores 20 in the bottom. Through the radial channels 21, the annular duct 19 is connected to the inner annular duct 22 which surrounds the connecting flange 23 of the outlet pipe 13 in the middle and which communicates with the supply medium 24 of the heating medium.

The outer ring channel 19 corresponds to a similar ring channel 25 on the upper side of the melting boiler, which is also connected to the channels 18 and also to the heating medium outlet pipe 16 via bores. The heating medium enters the bottom outer annular duct 18 through the supply pipe 24, the inner annular duct 22 and the radial ducts 21, from which it rises upwards through the ducts 18 inside the ribs 17, flows again in the upper, outer annular duct 25 and exits therethrough through the outlet duct 26.

The ring channel 25 surrounds the base 27 of the cover 8, to which the cover can be attached by means of three quick-release fasteners 28. The agitator 8 has a vertical shaft 29 parallel to the ribs 17 with three bifurcated, large propeller blades 30 extending almost as far as the side wall 11. These rotate the TNT melt so that it presses downward in the central region in the vicinity of the shaft, runs radially outwards at the bottom and rises again upwards in the side wall parallel to and between the ribs 17.

The melting boiler 6 comprises the heating and cooling system shown in Figure 4 for the heating medium. It consists of a coarse-controlled primary circuit 31 and a finely controlled secondary circuit 32 in terms of the temperature of the heating medium. to the control member 36 in the presence of steam from the heat exchangers.

The secondary circuit 32 passes from the primary circuit 31 through the mixing valve 37, the recirculation pump 38, through the melting boiler 6 described above and back to the primary circuit. Behind the melting boiler, a cross-branch to the mixing valve 37 is connected to the return, to which a heat exchanger 39 is connected, to which the fan 40 supplies cooling air L. The pneumatic relative / integral controller 41 processes the heating medium temperature sensor 42 Respectively these measurement signals and the preselected TNT melt temperature act on the mixing valve 37 of the controller 41 so that the controlled mixing ratio between the heated heating medium of the primary circuit 31 and the cooler heating medium of the heat exchanger 39 results in a set temperature of the heating medium in the melt boiler channels.

A second secondary circuit 44 branches off from the primary circuit 31, comprising a mixing valve 45, a recirculation pump 46, a controller 47 and a temperature sensor 48, which provides heating of the outlet pipe 13.

Claims (3)

8 67838 An explosive melting boiler with a propeller mixer (8) arranged in its interior and having a cavity in the side wall (11) and possibly in the bottom (12) consisting of a smooth outer jacket (14) and an inner jacket (15) for a flow of heating medium by means of an indoor explosive indirectly temperable, characterized in that each propeller shaft (29) of the agitator (8) is located vertically and that the inner jacket (15) of the side wall (11) is folded in a circumferential manner to form perpendicular ribs (17) pointing in a circumferential manner in each case restrict a separate channel for the heating medium. Melting boiler according to Claim 1, characterized in that the folded inner jacket (15) has its outer corrugated peaks (16) against the outer jacket (14). Melting boiler according to Claim 1 or 2, characterized in that the ribs (17) have an approximately triangular cross-section.