DE2015824A1 - - Google Patents

Description

PATENT LAWYERS ■ MUNICH 2
VAL 33
TEL. 0811/226894
295051
CABLES: THOPATENT
TELEX: TO FOLLOW Dipi formerly Dr. D. Thomsen Dtpi.-ing. H. Tiedtke
Dipi.-chem. Q. BühHng FRANKFURT (MAIN) 50
FUCHSHQHL 71
TEL. 0611/514666 Dipi-ing W. Weinkauf f

Answer requested to:

Please reply to: 201 5 8 24

8000 Munich 2 April 2, 1970

case M.21809 / T 3543

Imperial Metal Industries (Kynoch) Limited Birmingham / Great Britain

Process for the production of solid propellant charges

The invention relates to methods of casting of solid propellant charges for rocket engines as well as charges that have been produced by such processes.

Solid propellant charges for rocket motors are usually produced by known casting processes. Is the If the propellant charge required a simple straight cylinder, there are two alternative casting processes, one of which is in it consists of pouring each charge in an appropriate form and the second is to cast multiple lengths at the same time, after which the cast product is cut into the desired lengths will. With either of these alternative procedures, it may be necessary be to machine the end faces of each load to remove any unsatisfactorily cast sections.

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Oral agreements, especially by telephone, require written confirmation urasdnar Bank (Munich) account 109103 · Deutsche Btnk (Munich) .KJo. 51/382% · Vorein »b« nk (Munich) account 331368. Hypo-Dank (Munich) account 3 312183

Many desirable shapes for cast propellant charges are not simple straight cylinders with flat ends, but rather are formed with a straight cylindrical section with an extension with a non-planar end shape. Typical Examples of non-even end shapes are truncated cones and crownings. The chosen final shape is determined by the The ballistic properties required for the cargo are determined.

There are two methods of producing this form of charge. The first method will be simple straight cylinders manufactured as a single piece or in multiple lengths, whereby - each load is then converted into the desired one Shape is edited. This procedure is time consuming in view of the number of machining operations for any significant number of units cast individually, the process in each case being costly in material and harbors the dangers that arise during mechanical operations on solid propellant charges.

The second alternative of casting the solid propellant charge into the final shape is in the British patent application No. 25 977/66 (Serial No. 639 176). No machining is necessary with this process and there should be no improperly cast portions of the load.

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Although those described in the aforementioned patent application Processes are basically satisfactory, but they deal with pouring the solid propellant charges one at a time, so that the object of the invention is to a process for the casting of solid propellant charges create in which a plurality of charges are cast in a single casting process.

According to the invention there is a method for casting a plurality of solid propellant charges for rocket motors in that a plurality of Introduces mold powder quantities, each of which is separated from each adjacent quantity by a corresponding separator. is, which extends across the cavity and has through holes that you can the mold powder with any corresponding displacement of the separating member or the separating members by stamping pressure from at least one End of mold cavity compressed; that you can get air out of the Gaps between the molding powder grains by the introduction of a molding liquid at one end of the mold cavity and the passage of the liquid through the powder via the openings or holes of the partition member or members removed; that one hardens the propellant charge formed from each amount of casting powder to a solid mass, the stamp pressure Maintained essentially the same value from the first application of the ram pressure until complete hardening

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and then the solid propellant charges are removed from the mold cavity.

Advantageously, the mold cavity is formed in a shape that is divided in its longitudinal direction for removal to facilitate the solid propellant charges from the mold cavity.

The mold cavity is advantageously covered with a combustion-inhibiting coating before the quantities of casting powder are introduced Material provided.

Furthermore, each separating member is advantageous either on its surfaces facing the quantities of casting powder with a Separating layer provided to prevent sticking of the solid propellant charges to the separating member, or alternatively, of a Plastic material formed that does not adhere to the solid Propellant sticks.

Furthermore, the casting liquid is advantageously introduced into the mold cavity under pressure.

The pressure is expediently applied to the casting liquid with a gas which is inert towards the casting liquid and the casting powder exerted under a pressure of 0.35 to 7 kg / cm.

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The casting liquid is advantageously desensitized nitroglycerin and the inert gas nitrogen.

Advantageously, the casting powder is mainly nitrocellulose and the propellant charge formed from each amount of casting powder becomes at 38 ° to 71 ° C. for 144 to 24 hours hardened.

The ram pressure is advantageously sufficient to exert a pressure on the casting powder so that the powder grains are compressed ^{at 0.7 to 70 kg / cm 2.}

The invention also extends to a solid propellant charge for a packet motor, which according to an invention according to the method has been produced.

The invention is illustrated in the following with the aid of a schematic Drawings explained in more detail.

Fig. 1 shows in a partially sectioned elevation a first loaded mold set for casting a plurality of solid propellant charges;

FIG. 2 is an elevational view corresponding to FIG. 1 second loaded form set;

FIG. 2A is an enlargement of part ¹ X 'in FIG.

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According to FIG. 1, a mold set 1 has two halves 2, 3, which are separated along a longitudinal plane of the mold set 1. The halves 2, 3 are connected to each other by bolts 4, extending through bolt holes 5 provided in two flanges 6, each flange extending from one corresponding half 2, 3 extends away.

The mold set 1 has a base plate 7 to which the halves 2, 3 are bolted at 8. The base plate 7 is provided with an annular drainage channel 9, which via channels 10, 11 to an outlet nipple 12 for casting liquid leads. The form set 1 also has a head unit 13 which has a pneumatic punch 14, which consists of a Piston 15 (shown in its lowest position), from which a projection 16 extends, the upper end of which is provided with an air supply nipple 17, as well as from a Piston rod 18. The air supply nipple 17 is connected via channels 20 to an air cylinder 19 in which the piston is reciprocable. The air cylinder 19 is also provided with a vent hole 21, which is located on the side in the cylinder 19 opens, which is separated from the channels 20 by the piston 15.

The piston rod 18 is connected by a connecting piece 22 to a head plate 23, which is the lower limit the casting liquid chamber 24 forms. The headstock

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is provided with a number (e.g. 32) holes 37 which typically have a diameter of 1.19 mm. The casting liquid feed chamber 24 is through the head plate 23, the adjacent inner walls of the halves 2, 3 and by a Limited plate 25 through which the piston rod 18 goes. The piston rod 18 is provided with suitable sealing rings 26; furthermore, sealing rings 27, 28 are between the Projection 16 and a top plate 29 or between the top plate 29 and the wall of the air cylinder 19.

The casting liquid feed chamber 24 is provided with a Casting liquid inlet. 30, which can be accessed via channels 31 is connected to a casting liquid supply nipple 32.

The casting liquid chamber 24 is also provided with a Inlet 34 protruding from the plate 25 and connected to the outside of the head unit 13 through a channel 35 is. The channel 25 is equipped with a gas inlet nipple, whereby gas is introduced into the chamber 24 under pressure can be.

The head unit 13 is bolted to the upper ends of the halves 2, 3 as shown at 33 '.

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· "8" ■

The halves 2, 3 delimit a mold cavity 40 (which as shown in Pig. I contains propellant charges to be described later), the ends of which through the top plate and the base plate 7 can be determined. Between these ends, the mold cavity 40 is a simple straight cylinder. In the mold cavity 40, a plurality of partition members are arranged, which have a function to be described later and each of which has a profiled top 42 and a planar bottom 43 which is represented by a number (e.g. 32) Holes 44 are interconnected, each having a typical diameter of 1.19 mm. Each separator 4i is provided immediately next to the side or surface 43 with a separating membrane 45, which in this example has the shape a simple disc, but the underside or lower surface of this disc may be shaped or profiled can. Each membrane 45 is provided with holes 46 which correspond to the holes 44 of the separating member 41 and with these cursing. Each separator 41 and its associated separator

membrane 45 are expediently made of compatible plastic materials molded, e.g. from polyethylene terephthalate, polypropylene, polyacetate resin, polycarbonate resin, polyamide resin or polytetrafluoroethylene. The material chosen must be gin material that does not adhere to the propellant charge with which it is used. Alternatively, you can use any Separating member 41 and each separating membrane 4 5 from eggplanted Metals are produced, provided they have surface coating *

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make of suitable release agents. The edges the opposing end faces of the separators 41 and diaphragms 45 are beveled or chamfered to form an annular notch 49.

The mold cavity 40 has (although not necessary) a tubular covering (not shown) of a suitable material combustion-inhibiting material, e.g. made of cellulose acetate, that is transparent, or made of a flame retardant elastomeric connection. "

During use, the form set 1 is divided up in that the halves 2, 3 are bolted to one another and placed on the base plate 7. The mold cavity 40 is provided with a tubular covering of combustion retardant as required Material provided, wherein at the lower end of the mold cavity 40 one of the separating members 41 with his associated separating membrane 45 is arranged. In this state, the head unit 13 is not at the top of the Form set attached.

The first quantity of casting powder is then poured into the mold cavity 40, which in this example consists of chopped, extruded strands of preferably nitrocellulose, the resulting grains having a diameter and a length of about 0.76-1.27 mm. The first amount is then matched for height and then with a hand tool

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slightly squeezed.

Then the next separating member 41 with separating membrane 45 is introduced from the upper end into the mold cavity 40 and pushed against the lower end so that these parts rest on the upper side of the first quantity of molding powder.

Then a second amount of casting powder / which is usually, but not necessarily, the same powder, as used for the first lot, inserted into mold cavity 40, leveled and from the top of the second separator 41 compressed.

This process is repeated until the mold cavity 40 is approximately filled with a range of mold powder quantities each of which is separated from the adjacent set by a corresponding separator with a separating membrane.

It should be noted that it is not important that the same casting powder be used in every quantity, provided that the casting can be carried out for all quantities using the same casting liquid, pressures, temperatures and curing times. In addition, the different quantities need not have the same dimensions. In addition, any or every quantity of mold powder can have a number of fractions of different masses,

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-n-

to obtain a number of different levels of propulsion on the corresponding final finished load.

When the loading of the mold cavity 40 is complete, the arrangement is in a state that the level of the uppermost quantity of mold powder is very close to the upper end of the mold cavity 40 and the piston 15 is in its uppermost position so that the level of the uppermost quantity of mold powder is located on the piston fixed head plate 23 is in its highest position; the head unit 13 is then bolted to the upper ends of the halves 2, 3 with the aid of the bolts 33. ■

The mold powder is then compressed, by Supply of compressed air through the air supply nipple 13 into the air cylinder 19, so that the piston 15 and thus the head plate 23 pressed down and the casting material grains with

2 a pressure in the range from 0.7 to 70 kg / cm, usually

2
3.5 to 10.5 kg / cm are used. This pressure acts on the uppermost amount of mold powder, and through this powder and the uppermost partition member 41 and the partition membrane 45, the pressure on the next mold powder etc. is transmitted to the whole series of mold powder quantities. This leads to a displacement of all separating members 41 with associated membranes 45; the transverse dimensions are designed so that these parts can slide in the tubular Hemmbelag without difficulty. The size of the grains of the casting powder is

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2015

that they do not readily pass through the holes 44, 46 and that they become immobile under the applied pressure.

The casting liquid canister 24 is then desensitized via the feed nipple 32, the channel 31 and the inlet 30 Nitroglycerin supplied in such an amount that on the top of the head plate 23 a gives a sufficient amount of desensitized nitroglycerin. This is achieved in a known manner in that nitrogen is supplied to the top of the desensitized nitroglycerin reservoir connected to nipple 32 is. The nitrogen is on a surface above atmospheric

2 see "» pressure lying pressure that is in the range of 0.35 to 7kg / cm and preferably 1.05 to 3.5 kg / cm. This pressure pushes the nitroglycerin through the holes 37 into the top one Amount of casting powder. Due to the compressed state of the casting powder grains, the nitroglycerin migrates through this amount an almost completely horizontal horizon and pushes all air out of the space between the grains. While this is taking place, the addition of nitroglycerin to chamber 24 ensures that the top surface or the top of the head plate 23 is always covered with nitroglycerin. This prevents any gas passage with the glycerin from the chamber 24 into the casting powder.

Reached the horizon of the desensitized nitro-009847 / 1 030

glycerins the top separator 41, it being all interstitial gas has squeezed out of the uppermost quantity of casting powder, the liquid migrates through the holes 44, 46 into the next amount of casting powder and again forms an almost completely horizontal horizon, which is then created by this amount of casting powder wanders.

The nitroglycerin migrates in this way through all the casting powder until it arrives at the lowest "separating member 41 with membrane 45, whereupon it enters the annular channel 9 and from here through channels 10 and 11 to the outlet nipple 12. If this condition occurs, observe the." Operator that only a small amount of excess nitroglycerin exits through the nipple 12, the absence of any sign of gas bubbles means that all interstitial gas has been forced out by the pouring liquid. The exit nipple 12 is then closed by any known method and it becomes the The supply of nitroglycerin to the chamber 24 is terminated, with a steady amount of nitroglycerin being maintained at the top of the top plate 23. A supply of nitrogen then begins through the nipple 36 at the same level as it was applied to the nitroglycerin reservoir, the nitrogen supply being started by pressure applied to the head plate 23 by continuous compressed air drove into the cylinder 19 with the required head is maintained.

When using desensibillsiertem nitroglycerin · 009847/1030

and nitrocellulose can elapse from touching each other 30 to 40 minutes before the passage of nitroglycerin is hindered by the swelling of the nitrocellulose granules so that the length of the mold cavity and that of the nitroglycerin applied pressure can be determined by the need to stop the supply of nitroglycerin during this time. In practice, mold cavities 3 to 6 meters in length can be provided without difficulty, the main limitation being is given by practical handling considerations.

The contraction of the nitrocellulose cast powder mass occurs during the absorption of the desensitized nitroglycerin through the powder, the pressure exerted by the head plate 23 being caused by the continuous supply of Air is maintained through the air supply nipple 17 in accordance with the progress of the shrinkage. sources of the powder is possibly due to the physical effect between the powder and the liquid, so that the Head plate 23 is forced to retreat, with air through the nipple 17 while maintaining the selected pressure

is pressed. During the swelling (gelling) of the powder, the grains tend to coalesce. At the same time will a bond is formed between the gelled mass and any inhibitor material. The hardening is done by heating the propellant mass to a temperature between 38 and 71 C,

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usually 65 ° C for a period of 144 - 24 hours, usually causes 96 hours, with thermal expansion and subsequent compression and consolidation with it subsequent cooling and contraction, which is absorbed by the movement of the pressure plate. Air pressure and nitrogen pressure are used during curing with the Maintain the desired pressure level.

After hardening, the head unit 13 is removed and the mold halves 2, 3 are removed from the base plate 7 and separated from one another. 'This will result in the poured solid propellant charges that are still in a row with the separating members 41 and separating membranes 45 are located between the individual propellant charges, with all these parts are located in the common tubular or tubular covering made of Hemmaterial or Inhibitprmaterial. The tubular jam lining is then severed at the notch between each charge, after which the charges of the intermediate separating members and separating membranes 45 are separated. The flame retardant material can be used after the completion of each solid propellant charge The inhibition of the charge ends, which is necessary, can then be effected. With modifications In this example, it is not necessary that the mold cavity 40 contain the combustion retardant material; it can the solid propellant charges without any inhibitor material

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or casting inhibitor material, with the inhibitor material as required can be applied subsequently by methods known per se.

It is also possible to replace the mold halves 2, 3 with a complete piece of pipe; in this case will
the casting set of charges, dividers and diaphragms 41, 45 is pushed out from one end of the disassembled mold.

In addition, it can be beneficial, not only
from one end as described above but from both ends of the mold cavity 40 to exert pressure on the quantities of mold powder.

In addition, the direction of supply of the casting liquid can be reversed, with liquid then flowing through the Nipple 12 is supplied and discharged through the nipple 32.

Figures 2 and 2A show a second example of the invention which differs from the first embodiment in that the mold cavity 40 has a core pin 60 contains, parts corresponding to one another having been given the same reference numerals.

The core pin 60 is at its lower end with a Q098A7 / 1030

Provided projection 61, which has thread at 62 and the is clamped to a base plate 24 with a nut 63. The bottom plate 24 sits at the bottom of the mold cavity 40 and is typically provided with 32 holes, the ends of which open into two annular channels 65, which are located on each end face of the Base plate 64 are located. The channels 65 at the bottom of the bottom plate 64 are with the casting liquid drainage channels or drainage channels 10, 11 connected.

From the bottom plate 64, the core pin 60 is cylindrical and extends coaxially to the mold cavity 40 to the upper end 66 of the core pin 60. The end 66 is seated displaceable in a pressure member 67 which is supported on the head plate 23, which in this case is annular and surrounds the core pin 60. The pressure member 67 is on the Connector 22 carried by piston 18.

With respect to the core pin 60, each is a separator 41 also ring-shaped, with upper and lower separating membranes 45 being provided in this example. The through the. Holes 44 going through separators 41 are also provided with annular channels 68 provided, in which the holes in the membranes 45 open. .

The notches 49 are replaced by circumferential grooves 69 in the separating member 41. The separators 41 are expedient

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made of polypropylene, while for the membrane 45 relatively flexible polythene is used.

This embodiment is used / to cast a plurality of solid propellant charges in the same way as explained with reference to FIG. 1, with the exception that before the insertion of the first separating member and its associated Membranes 45 of the core pin 60 with attached base plate 64 are arranged in the mold cavity 40. in the the rest, of course, tubular charges are generated.

The core pin does not have to have a circular cross-section but can have any ballistically advantageous cross-section have, for example, oval or star-shaped cross-section with any required number of star points.

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Claims (11)

. - 19 - Claims (U method for casting a plurality of solid propellant charges for reverse engines, characterized in that one accommodates in a mold cavity a plurality of quantities of molding powder, each of which is separated from each adjacent quantity by a corresponding partition member extending across the Mold cavity extends and has through holes that you can the casting powder cones with a corresponding displacement the partition member or members are compressed by ram pressure from at least one end of the mold cavity that one in the spaces between the grains of the casting powder existing air by introducing a casting liquid at one end of the mold cavity and passage of the liquid by driving the powder through the holes in the partition member or members, so that the amount of mold powder of each is expelled The propellant charge formed hardens to a solid mass from the beginning of the first application of the stamp pressure until the curing process is complete, leave the stamp on an im essential constant value and that one holds the solid propellant charges removes from the mold cavity. 2. The method according to claim 1, characterized in that that the mold cavity is formed in a shape suitable for Lighten the solid propellant charges from the mold cavity in Can be divided lengthways. QQ 98 4 7 /, 10.3 (X r- <■ -.- ', .- ■ 3. The method according to claim 1 or 2, characterized in that the mold cavity prior to filling the Molding powder quantities is lined with a coating made of a combustion-inhibiting material. 4. The method according to any one of the preceding claims, characterized in that each separating member on its surfaces facing the mold powder quantities with a Separating layer is provided to prevent sticking of the solid propellant charges to the separating member. 5. The method according to any one of the preceding claims 1 to 3, characterized in that each separator is formed by a plastic material that does not stick to the solid propellant charges. 6. Ancestors according to one of the preceding claims, characterized in that the casting liquid is introduced into the mold cavity under pressure. 7. The method according to claim 6, characterized in that the pressure exerted on the casting liquid with With the help of a gas that is inert to the casting liquid and the casting powder and applied under a pressure of 0.35 to 7 kg / cm will. 00 9 847/1030 8. The method according to claim 7, characterized in that that the casting liquid is desensitized nitroglycerin and the inert gas is nitrogen. 9. The method according to claim 8, characterized in that the casting powder is mainly nitrocellulose and that the propellant charge formed by each quantity of casting powder is cured for 144 to 24 hours at 38 ° to 71 ° C. 10. The method according to any one of the preceding claims, characterized in that the stamp pressure is sufficient to exert a pressure on the casting powder, in which the grains are compressed at 0.7 to 70 kg / cm. .-.- .. 11. Fixed propellant charge for a rocket motor according to a method according to the preceding claims. 00 98A7 / 10-3 0 Blank page