Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B33/00—Manufacture of ammunition; Dismantling of ammunition; Apparatus therefor
  • F42B33/02—Filling cartridges, missiles, or fuzes; Inserting propellant or explosive charges
  • F42B33/0214—Filling cartridges, missiles, or fuzes; Inserting propellant or explosive charges by casting
  • F42B33/0242—Filling cartridges, missiles, or fuzes; Inserting propellant or explosive charges by casting by pressure casting

Definitions

• the technical field of the invention is that of methods and devices for loading by casting an explosive material into a munition body.
• Explosive loading by casting is a conventional method. It generally comprises at least one tundish which is filled with an explosive material maintained in the liquid state.
• the castings use explosives associating a fuse explosive such as trinitrotoluene and explosives grains (such as hexogen and Octogen).
• a fuse explosive such as trinitrotoluene and explosives grains (such as hexogen and Octogen).
• the mixture is most often made at the level of the tank into which the fusible explosive is introduced first and then the other solid explosives in grains.
• the tank is provided with a stirring means that ensures a homogeneous mixture of components. It is also maintained at a temperature which is that now the explosive in the molten state (of the order of 90 ° for trinitrotoluene).
• the ammunition body for example a shell equipped with a riser
• the pouring valve is open which allows gravity flow of the explosive into the munition body.
• the charged body is then progressively cooled (inside suitable incubators and controlled in temperature), which leads to the solidification of the load.
• the riser conventionally makes it possible, on the one hand, to form a casting funnel and, on the other hand, to locate the deformations or sinkings of the free face of the explosive at the level of an element that will be removed. also the energetic crystal enrichment (hexogen, Octogen) of explosive loading of the body. This ensures a better homogeneity of the loading of the shell.
• the conventional casting process however, has limitations when the explosive material to be loaded is extremely viscous.
• High-viscosity explosives are, for example, composite explosives, which incorporate binders that must be polymerized after casting, or heat-fusible explosives that incorporate additives that greatly increase their viscosity.
• EP914069 discloses various examples of these compositions.
• Patent FR1184260 discloses a process for casting an explosive fuse material. According to this method, the tank is positioned on the munition via a funnel box which is depressurized to facilitate loading. However, this method is poorly suited to the casting of viscous explosive. Indeed the vacuum proposed by this patent occurs simultaneously casting. We do not control the level of vacuum achieved.
• the patent FR2428228 proposes a method of manufacturing an explosive body by vacuum casting. According to this method a heated casting bowl is connected to a mold by a transfer device incorporating a membrane which is broken by an overpressure in the bowl relative to the mold. This process is difficult to control and it requires the replacement of the membrane for each casting.
• WO03 / 078919 discloses a method of charging ammunition in which the ammunition body is closed by a lid connected to a means of evacuation.
• this document does not describe the structure of the tundish or how it is connected to the munition for casting.
• WO03 / 078356 also describes an installation for casting composite explosives. The purpose of this patent is specific to composites: to make the primary mix / hardener as far downstream as possible. According to this patent, the tank charged with explosive is then pressurized with the aid of a hydraulic cylinder in order to force the explosive / hardening mixture through a static mixer.
• the subject of the invention is a process for casting an explosive material in a munition body, in which process the explosive material is placed in the liquid or pasty state in the munition body via a pouring vessel closed by a pouring valve and disposed above the munition body, in which method the material is poured under vacuum into the munition body, the vacuum being produced in the tank on the one hand; and in the ammunition body on the other hand before carrying out the casting, characterized in that it positions before casting the munition body below the tank and then interposes a casting funnel ensuring a sealed connection between the tank casting and the ammunition body, then the vacuum is first made at the level of the tundish and then this vessel is isolated, the vacuum is finally made in the ammunition body and the funnel connected in a sealed manner to the body s, the vacuum level in the ammunition body and the funnel being higher than the vacuum level in the tank, then the pouring valve is opened.
• the invention also relates to a casting device of such a material, a device facilitating the adaptation of this casting process to all types of ammunition bodies and implementing simple means and consuming minimal energy.
• this device for casting an explosive material in an ammunition body comprises a sealed casting vessel closed by a pouring valve and which is disposed above the munition body possibly provided with a riser, which device is characterized in that it comprises at least one casting funnel interposed between the casting tank and the ammunition body (or the riser) funnel which can be connected in a sealed manner to both the ammunition body and the tank, means of evacuation being provided to achieve the vacuum at the level of the tank at the level of the munition body and the funnel, these means ensuring a vacuum level in the munition body and the funnel that is further than the vacuum level in the tank.
• the funnel may be integral with a bottom of the tank and have a sliding bowl relative to a fixed bucket, bowl intended to cap an upper part of the ammunition body (or raises).
• the sliding bowl may comprise a front portion provided with a circular groove intended to cooperate with an upper portion of the ammunition body (or the riser) groove at the bottom of which will be disposed a seal.
• the front part of the sliding bowl can be made in the form of a ring connected to the bowl by a ball joint.
• the sliding bowl may include an internal baffle delimiting a hole of diameter less than or equal to the inner diameter of the ring deflector guiding the explosive material during casting.
• the funnel may be connected in a sealed manner to the munition body by means of at least one inflatable bladder secured to the funnel and coming to bear against a cylindrical body surface 'a raises solidarity of the body.
• the sliding bowl can also carry an endoscopic sensor to visualize the level of casting.
• the vacuum means will comprise at least one vacuum pump connected on the one hand to the tank and on the other hand to the funnel, a first stop valve being interposed between the pump and the tank and a second cock of the stopping being interposed between the pump and the funnel, control means for opening and / or closing each valve as well as the control of the pouring valve.
• Figure 1 is a general block diagram of a casting installation implementing the method and the device according to the invention
• Figure 2 is a longitudinal sectional view of an embodiment of a pouring funnel according to the invention, funnel shown in the inactive position, away from the body of ammunition
• FIG. 3 is a view similar to FIG. 2 but shows the casting funnel in the active position, coupled to the ammunition body, and
• Figure 1 shows schematically a casting installation 1 according to the invention.
• the installation 1 mainly comprises a pouring vessel 4 which is disposed above one of the munition bodies 2. Concretely the tank 4 will be fixed on a support not shown and position the ammunition body 2 by moving the pallet 3.
• the tank 4 is made in a conventional manner in a material resistant to corrosion, for example stainless steel. It comprises a lid 4a which can be tilted to close the tank in a sealed manner. It contains an agitator means 5, which is shown very schematically here, and which comprises in a well known manner rotary blades driven by a motor (not shown).
• the tank 4 comprises a nozzle 4b closed by a pouring valve 6 whose opening and closing are controlled by a control means 7, for example a programmable controller.
• a control means 7 for example a programmable controller.
• the tank 5 is connected to a first heating means 8a, such as a boiler.
• a heat transfer fluid is led from the boiler 8a to the tank through a pipe 9 on which is placed a thermostatic valve 10.
• the vessel has a double wall inside which can circulate the heat transfer fluid.
• the nozzle 4b is connected to a second boiler 8b by a thermostatic valve 11.
• This ensures a homogeneity of the temperature of the explosive material both inside the tank 4 and at the nozzle 4b.
• the implementation of two separate boilers ensures independent heating for the tank 4 and the nozzle 4b.
• the temperature will be chosen according to the melting characteristics of the material to be cast. Generally for fusible explosive materials, the temperature is between 75 0 C and 100 ° C.
• FIG. 1 shows a melter 12 which is carried by a pivoting arm 13.
• This element makes it possible to melt a pyrotechnic component before it is introduced into the vessel 4.
• a first fuse component is introduced directly into the melter 12 in which it is melted.
• the valve 16 can be opened in order to drain it into the tank 4 and mix it with the second component introduced progressively into the tank 4.
• the agitator 5 will ensure the homogeneity of the mixture.
• the latter is also connected to the first boiler 8a by a pipe 15 on which is disposed a thermostatic valve 14.
• the various thermostatic valves 10, 11, 14 may advantageously be controlled by the temperature controller 7 (the links with the PLC are not shown for clarity of the figure).
• temperature probes will be arranged at the level of the different pipes as well as the tank, the nozzle and the melter.
• a pouring funnel 18 is fixed at a bottom of the tank, that is to say here to the nozzle 4b. It is intended to ensure the vacuum casting of the explosive in the munition body 2.
• vacuum means 17 such as a vacuum pump
• These means make it possible to carry out the vacuum at the level of the tank 4 and also at the level of the casting funnel 18, the nozzle 4b and the munition body 2 on which the funnel 18 is positioned.
• the vacuum pump 17 is thus connected to the tank 4 by a pipe 21 on which is placed a first shut-off valve 22.
• the vacuum pump 17 is also connected to the funnel 18 (more precisely to the nozzle 4b situated above the funnel) via a pipe 19 on which is placed a second shut-off valve 20.
• each valve 20,22 and the control of the pouring valve 6 are performed by the programmable controller 7.
• the method according to the invention aims to ensure a vacuum casting of the material in the munition body.
• the structure of the shell bodies (hollow body with a single opening of relatively small diameter, of the order of 40 to 50 mm), makes it difficult to perform a vacuum casting.
• the invention solves such a problem by proceeding to a vacuum of the interior of the body of the munition, by the pouring orifice itself, and independently of the vacuum made elsewhere in the tank.
• Figures 2 and 3 show more precisely the structure of the pouring funnel 18.
• This funnel 18 is integral with the nozzle 4b (or the bottom of the tank 4). It is constituted by a bucket 23 fixed to the tank 4 by screws (not shown) disposed at an outer collar 23a. Seals 24 seal at the attachment of bucket 23 to the tank
• the funnel 18 also comprises a bowl 25 which is slidably mounted relative to the cup 23.
• This bowl has an internal cylindrical portion 25a which slides in a complementary bore of the cup 23.
• O-ring seals 26 are arranged in worn grooves by the bucket 23. They provide the desired seal against the vacuum.
• the bowl 25 carries a circular plate 25b on which are fixed guide bushes 27 (regularly distributed angularly on the plate 25b), sleeves in which slide rods 28 integral with the collar 23a of the bucket.
• An operator (not visible in the figures) is arranged between the flange 23a and the plate 25b so as to control the axial displacement of the bowl 25 relative to the bucket 23.
• This motorization is for example constituted by a small linear jack which is positioned in instead of one of the sockets 27 / rods 28.
• the front part of the sliding bowl 25 is in the form of a ring 29 which is connected to the bowl 25 (via the plate 25b) by a ball joint. It can thus be seen in FIG. 2 that the ring 29 has an outer spherical profile and that it is housed in a complementary cavity carried by the plate 25b. The fastening of the ring 29 and the plate is ensured by a washer 30 which is screwed to the plate 25b and which also has a spherical profile complementary to that of the ring 29.
• Seals 31 are provided between the ring 29 and the bowl 25. These seals are arranged between the ring 29 and the plate 25b and between the ring 29 and the washer 30.
• the ring 29 is intended to provide a seal against the vacuum between the funnel 18 and the ammunition body 2 (and more particularly here between the funnel 18 and the riser 2a of the shell).
• the front portion of the sliding bowl 25, which is constituted by the ring 29, comprises a front portion provided with a circular groove 32 which is intended to cooperate with the upper cylindrical end 33 of the riser 2a.
• a seal 34 is disposed at the bottom of this groove 32. This seal will be crushed by the upper end
• the sliding bowl 25 incorporates an inner deflector (or nozzle) 35 which delimits a passage whose diameter is less than or equal to the internal diameter of the ring 29.
• This deflector is realized for example bronze and it is fixed to the bowl 25 in a removable manner. Indeed we can change the deflector 35 to vary the casting diameter to adapt the device to a different shell body. The deflector 35 guides the explosive material during casting avoiding any contact between this material and the ring 29.
• Figure 3 shows the funnel when in casting position.
• the motor (controlled by the programmable controller 7) has moved down the plate 25b bearing the ring 29.
• the latter has capped the extension 2a of the ammunition body 2.
• the ball joint allows to allow a slight misalignment at this time. positioning which facilitates the loading operations by allowing a slight uncertainty of positioning of the pallet 3 with respect to the funnel 18.
• the seal 34 is crushed by the end 33 of the riser 2a.
• the casting funnel 18 then provides a tight connection between the munition body 2 and the tank 4.
• the vacuum pump 17 sucks the air contained in the nozzle 4a (via the tap 20) it also sucks the air contained in the funnel 18 and in the ammunition body 2.
• the lid 4a of the vessel 4 is closed again.
• the components are then kneaded to obtain a homogeneous paste in composition and temperature. Temperature probes arranged inside the tank will control the evolution of the process.
• a vacuum is produced, first of all at the tundish 4.
• the valve 22 is opened, the valve 20 being closed.
• Valve 22 is then closed to isolate this vessel under vacuum. Then, with the means 17, the vacuum is made in the ammunition body 2 and the funnel 18 (which has previously been sealed to the ammunition body 2). For this we open the valve 20, the valve 22 being closed.
• the filling of the ammunition body 2 is then assured despite the viscosity of the mixture.
• valve 6 After obtaining the desired filling level, the valve 6 is closed again.
• the measurement of the volume is ensured by means of an endoscopic probe 36 (FIG. 3) which is introduced radially into the funnel 18 through a hole 37 .
• This probe carries an optical sensor 39 which is arranged radially relative to the probe so as to be able to observe the contents of the extension 2a.
• the probe 36 is slidably and sealingly disposed in this hole and it does not disturb the vacuum obtained.
• the probe is connected to a monitoring screen 38 (FIG.
• the method and the device according to the invention are of course adaptable to other types of ammunition than shell bodies, for example to the vacuum casting of explosive charges of missiles, rockets or bombs.
• the invention is particularly suitable for casting very viscous materials.
• the vacuum is preferably made in the tank 4 and then in the body 2 while ensuring a difference in the vacuum level between the body 2 and the tank.
• the vacuum level will be chosen to be greater at the level of the body 2 than at the level of the tank 4, which will have the effect, during the opening of the pouring valve 6, of forcing the material of the tank towards the body 2
• the difference in vacuum level will depend on the viscosity of the material.
• FIG. 4 shows an alternative embodiment of the invention in which the funnel 18 is connected in a sealed manner to the body 2 of the munition via an inflatable bladder 40 secured to the funnel 18.
• This bladder 40 is made of rubber and has a toric profile. It is secured here to the sliding bowl 25 to which it is fixed by sealed means, for example by annular crimps. It is connected by a pipe 43 to a pump 42 which ensures its inflation and which is actuated by the control means 7.
• the bladder 40 is deflated, the riser 2a attached to the ammunition body 2 can be introduced into the funnel 18.
• the bladder 40 is inflated to an appropriate pressure it is applied against a cylindrical surface 41 of the extension 2a and thus ensures sealing.
• a deflector 35 guides the explosive material during casting avoiding contact between the material and the bladder 40.
• the bladder 40 also allows to allow a slight misalignment during the positioning of the ammunition which facilitates the operations loading by allowing a slight uncertainty of positioning of the pallet 3 with respect to the funnel 18.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• General Engineering & Computer Science (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Fire-Extinguishing By Fire Departments, And Fire-Extinguishing Equipment And Control Thereof (AREA)

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Publications (2)

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• 2007
  • 2007-10-29 FR FR0707598A patent/FR2923005B1/fr not_active Expired - Fee Related
• 2008
  • 2008-10-27 EP EP08871477.9A patent/EP2215426B1/de active Active
  • 2008-10-27 ES ES08871477T patent/ES2428900T3/es active Active
  • 2008-10-27 PL PL08871477T patent/PL2215426T3/pl unknown
  • 2008-10-27 WO PCT/FR2008/001513 patent/WO2009092884A2/fr not_active Ceased

Non-Patent Citations (1)

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