A method for preparing an end face patch of seven-hole multi-layer propellant

Abstract

This invention discloses a method for preparing end-face patches for seven-hole multilayer propellants, applicable to end-face sealing of multilayer propellants. The invention employs a honeycomb mold to constrain the propellant cylinders, enabling the orderly arrangement of the seven-hole multilayer propellant. The large diameter of the inner holes in the honeycomb mold facilitates filling of the propellant. A solvent-based swelling and sealing technique ensures a tight fit between the outer wall of the propellant and the inner wall of the honeycomb mold, effectively fixing the propellant's outer wall. The mold's cutting disc structure allows for the simultaneous removal of excess patch portions, yielding multiple samples with end-face patches, significantly improving preparation efficiency. This invention solves the problems of low preparation efficiency and poor quality of end-face patches for seven-hole multilayer propellants, providing a high-quality, high-efficiency technical means for preparing end-face patches for seven-hole multilayer propellants.

Description

Technical Field

[0001] This invention relates to the field of propellant technology, and in particular to surface treatment processes for multilayer propellants. Specifically, it relates to a method for preparing a seven-hole multilayer propellant by applying a patch to its end face. Background Technology

[0002] Multilayer propellants consist of inner and outer layers, prepared through co-extrusion. Currently, they are mainly tubular and sheet-like multilayer propellants. Because the bonding between their layers is much tighter than that of coating or desensitizing processes, they possess higher density, better stability, and excellent combustion escalation properties, making them widely used in small-caliber weapons. With the increasing demands for energy density from large-caliber, high-power artillery, existing coating and desensitizing processes cannot meet the high energy density requirements. Seven-hole multilayer propellants are one such technical solution. However, as the propellant diameter increases, the end-face area of ​​the seven-hole multilayer propellant increases rapidly, leading to a continuous decrease in combustion escalation properties. Therefore, the end-face treatment of seven-hole multilayer propellants becomes particularly important. The main surface treatment methods for propellants are: (1) using a rotating drum and spray gun, in which the propellant is placed in a rotating drum and the coating liquid is sprayed onto the surface of the propellant while the drum is rotating continuously, so that the surface of the propellant is covered with a coating layer. This method is obviously not suitable for the requirement that only the end face of the seven-hole multilayer propellant can be sprayed; (2) using a powder mixing method, in which the propellant is added to a pot containing coating material and stirred and rotated, so that the surface of the propellant is covered with a coating layer. This method is also not suitable for the requirement that only the end face of the seven-hole multilayer propellant can be sprayed; (3) manually attaching patches to the end face of the propellant, that is, manually attaching the end face of the propellant. This method is obviously not suitable for the preparation of a large number of propellant particles. Therefore, the existing preparation methods are designed for the full coating of the propellant and cannot meet the requirement that only the end face of the seven-hole multilayer propellant can be treated.

[0003] Based on the technical data currently available, there is no method for preparing propellant end faces that can be mechanically attached in large quantities. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for preparing end face patches of seven-hole multilayer propellants using mold constraint, solvent swelling, and rapid cutting techniques.

[0005] The preparation method provided by this invention comprises the following steps:

[0006] (1) Calculate the swelling coefficient based on the seven-hole multilayer propellant formulation.

[0007]

[0008] r is the swelling coefficient of the seven-hole multilayer propellant. w r is the swelling coefficient of the outer layer of the seven-hole multilayer propellant. n D is the swelling coefficient of the inner layer of the seven-hole multilayer propellant, and e is the outer diameter of the seven-hole multilayer propellant. w The thickness of the outer layer of the seven-hole multi-layer propellant;

[0009] (2) Calculate the dimensions of the honeycomb mold and inner holes based on the dimensions and swelling coefficient of the seven-hole multilayer propellant.

[0010] H k <L

[0011] D < D k <r×D

[0012] H k L is the depth of the inner hole, and the thickness of the mold is the same as the depth of the inner hole. D is the length of the seven-hole multi-layer propellant. k The diameter of the inner hole;

[0013] (3) The honeycomb mold is disc-shaped and has multiple inner holes. The mold cutter disc matches the honeycomb mold, is disc-shaped and has multiple through holes, and each through hole has a protruding blade at one end.

[0014] (4) Place the seven-hole multilayer propellant in the inner hole of the honeycomb mold;

[0015] (5) Applying solvent in small amounts and multiple times allows the seven-hole multilayer propellant to swell and adhere completely to the inner wall of the hole.

[0016] (6) Use a blade to trim the protruding seven-hole multi-layer propellant end faces at both ends of the honeycomb mold;

[0017] (7) The formulation components of the outer layer of the seven-hole multilayer propellant are used for tableting, with a thickness of [missing information].

[0018] P h =r×e w

[0019] P h The thickness of the patch;

[0020] (8) Spray solvent onto both ends of the honeycomb mold and attach the patch to both ends of the honeycomb mold;

[0021] (9) Use a mold cutter head to remove excess parts of the patch in one go;

[0022] (10) Place the honeycomb mold in an oven to dry it. After the solvent evaporates, take out the seven-hole multilayer propellant sample with end face patches.

[0023] Therefore, by using a honeycomb mold to constrain the propellant column, using a solvent to swell the seven-hole multilayer propellant to fix it, attaching the entire patch to the end face of multiple seven-hole multilayer propellants, and then using a mold cutter to remove the excess part of the patch in one go, it is possible to complete the preparation of the seven-hole multilayer propellant end face patch sample with high quality and high efficiency.

[0024] The present invention provides a method for preparing an end-face patch for a seven-hole multilayer propellant, which has the following advantages compared with the prior art:

[0025] (1) Using a honeycomb mold to constrain the propellant column enables the orderly arrangement of the seven-hole multi-layer propellant, and the large inner diameter of the honeycomb mold makes it easier to load the seven-hole multi-layer propellant. Compared with the prior art, the orderly arrangement of the seven-hole multi-layer propellant can be achieved through the reasonable design of the honeycomb mold, providing a technical means for the efficient patching of the propellant end face.

[0026] (2) The technique of using solvent to swell and seal the propellant can tightly fit the outer wall of the seven-hole multilayer propellant with the inner wall of the honeycomb mold, thus fixing the propellant in place. Moreover, fluctuations in the outer diameter of the propellant within a certain range do not affect the sealing effect. Compared with existing technologies, solvent swelling and sealing does not introduce other impurities and is applicable to a wider range of propellant diameters.

[0027] (3) The mold-cutter head structure allows for the removal of excess portions of the patch in one go, resulting in multiple samples with end-face patches, significantly improving preparation efficiency. Compared with existing technologies, the mold-cutter head one-time molding method has better process stability and higher efficiency, ensuring that the seven-hole multilayer propellant of the end-face patch has higher combustion escalation.

[0028] Therefore, this invention solves the problems of low efficiency and poor quality in the preparation of seven-hole multilayer propellant end face patches, and provides a technical means for preparing high-quality and high-efficiency seven-hole multilayer propellant end face patches. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a honeycomb mold.

[0030] Figure 2 This is a schematic diagram of the mold cutter head.

[0031] Figure 3 yes Figure 1 Sectional view along direction A.

[0032] Figure 4 yes Figure 2 Sectional view along direction B.

[0033] Figure 5This is a flowchart of the preparation process for the end face patch of a seven-hole multilayer propellant. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, the inner layer of the seven-hole multilayer propellant 3 consists of 70% nitrocellulose (12.6% nitrogen content) and 30% RDX (30%); the outer layer consists of 60% nitrocellulose (12.6% nitrogen content) and 40% nitroguanidine (40%). The seven-hole multilayer propellant 3 has an outer diameter of 10 mm, a length of 18 mm, an inner hole diameter 6 of 0.4 mm, and an outer layer thickness of 0.5 mm. The honeycomb mold 2 contains nineteen inner holes 1. The mold cutter head 4 contains nineteen through holes 5, each through hole 5 having a cutting edge 8 at its left end. The dimensions of the mold cutter head 4 match those of the honeycomb mold 2.

[0036] according to Figure 5 The preparation steps for the end-face patch of the seven-hole multilayer propellant shown are as follows:

[0037] (1) The swelling coefficient of the seven-hole multilayer propellant 3 was calculated based on its formulation. The calculated swelling coefficient of the inner layer of the seven-hole multilayer propellant 3 was 1.3, and the swelling coefficient of the outer layer 5 was 1.2.

[0038]

[0039] The swelling coefficient of the seven-hole multilayer propellant 3 was calculated to be 1.23.

[0040] (2) Calculate the dimensions of the honeycomb mold 2 and the inner hole 1 based on the dimensions and swelling coefficient of the seven-hole multilayer propellant 3.

[0041] H k <18

[0042] 10 < D k <1.23×10

[0043] Take H k The depth is 16mm, meaning the depth of the inner hole 1 and the thickness of the honeycomb mold 2 are both 16mm. Let D be... k The diameter is 11mm, meaning the diameter of the inner hole 1 of the honeycomb mold 2 is 11mm;

[0044] (3) The honeycomb mold 2 is disc-shaped with a size of Φ85mm×16mm and has nineteen inner holes 1. The mold cutter 4 is disc-shaped with a size of Φ85mm×16mm and has nineteen through holes 5 with a size of Φ11mm×16mm. The left end of each through hole 5 is a blade 8. The distribution of through holes 5 is consistent with that of inner holes 1.

[0045] (4) Place the seven-hole multilayer propellant 3 into the inner hole 1 of the honeycomb mold 2;

[0046] (5) Acetone is used as the solvent. The solvent is sprayed in small amounts and multiple times so that the seven-hole multilayer propellant 3 swells and adheres completely to the inner wall of the hole.

[0047] (6) Use a blade to trim the end faces of the seven-hole multi-layer propellant 3 protruding at both ends of the honeycomb mold 2 so that the end faces are flush and there are no protruding seven-hole multi-layer propellant 3.

[0048] (7) The same material as the outer layer of the seven-hole multilayer propellant 3 is used for tableting, with a thickness of [missing information].

[0049] P h =r×e w =1.23 × 0.5

[0050] The calculated thickness of the patch is 0.62 mm;

[0051] (8) Spray solvent onto both ends of the honeycomb mold 2 and attach the patch to both ends of the honeycomb mold 2;

[0052] (9) Use the mold cutter head 4 to remove the excess part of the patch in one go;

[0053] (10) Place the honeycomb mold 2 in an oven and set the oven temperature to 85°C for drying. Observe it every 8 hours. After the solvent evaporates, take out the seven-hole multilayer propellant 3 sample with end face patch.

[0054] The above steps yield the seven-hole multilayer propellant 3 with end-face patch. Since the outer wall of the seven-hole multilayer propellant 3 remains unchanged, the resulting seven-hole multilayer propellant 3 is a dense structure with the outer layer fully encapsulating the same formulation component material, exhibiting high density and good combustion gradation.

Claims

1. A method for preparing an end face patch of seven-hole multilayer propellant, characterized in that The steps are as follows: (1) Calculate the swelling coefficient based on the seven-hole multilayer propellant formulation. r is the swelling coefficient of the seven-hole multilayer propellant, r is the swelling coefficient of the seven-hole multilayer propellant, r is the swelling coefficient of the seven-hole multilayer propellant, r is the outer diameter of the seven-hole multilayer propellant, r is the thickness of the outer layer of the seven-hole multilayer propellant; (2) Calculate the dimensions of the honeycomb mold and inner holes based on the dimensions and swelling coefficient of the seven-hole multilayer propellant. The depth of the inner hole is given, and the thickness of the mold is the same as the depth of the inner hole. The length of the seven-hole multi-layer propellant. The diameter of the inner hole; (3) The honeycomb mold is disc-shaped and has multiple inner holes. The mold cutter disc matches the honeycomb mold, is disc-shaped and has multiple through holes, and each through hole has a protruding blade at one end. (4) Place the seven-hole multilayer propellant in the inner hole of the honeycomb mold; (5) Applying solvent in small amounts and multiple times allows the seven-hole multilayer propellant to swell and adhere completely to the inner wall of the hole; (6) Use a blade to trim the protruding seven-hole multi-layer propellant end faces at both ends of the honeycomb mold; (7) The formulation components of the seven-hole multilayer propellant outer layer are used for tableting, with a thickness of [missing information]. The thickness of the patch; (8) Spray solvent onto both ends of the honeycomb mold and attach the patch to both ends of the honeycomb mold; (9) Use a mold cutter head to remove excess parts of the patch in one go; (10) Place the honeycomb mold in an oven to dry it. After the solvent evaporates, take out the seven-hole multilayer propellant sample with end face patches.

2. The method for preparing an end-face patch for a seven-hole multilayer propellant according to claim 1, characterized in that, The dimensions of the honeycomb mold and its inner holes are calculated based on the size of the seven-hole multilayer propellant and its swelling coefficient. The honeycomb mold has a size of Φ85mm×16mm and N (N=1, 2, 3...) inner holes with a size of Φ11mm×16mm.

3. The method for preparing an end-face patch for a seven-hole multilayer propellant according to claim 1, characterized in that, Matching the honeycomb mold, the mold cutter head has a size of Φ85mm×16mm and has N (N=1, 2, 3...) through holes with a size of Φ11mm×16mm. Each through hole has a raised blade on the left end.

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