A gas generating agent and a high-output low-burning-temperature gas generator comprising the same

Abstract

This invention discloses a gas-generating agent and a high-output, low-burning-temperature gas generator composed thereof, belonging to the field of pyrotechnics. The gas-generating agent of this invention is composed of potassium nitrate, azodicarbonamide, ferrocene, and a binder. The gas generator of this invention includes an outer shell, an inner shell, the gas-generating agent, a charge box, a filter, a filter screen, an electric ignition tube, a nozzle, and a base. This invention meets the requirements of torpedo fuel tanks for low-temperature, low-burning-rate, low-combustion-impurities, and stable output pressure. It can achieve: gas temperature inside the cavity ≤80℃, gas water solubility ≤5%, and impurity particle diameter in the gas ≤5μm. It fills the gap in gas generators that output low-temperature, low-burning-rate gas and solves the problem of large volume and weight of external gas cylinders in torpedoes.

Description

Technical Field

[0001] This invention relates to the field of pyrotechnics, and more particularly to a gas-generating agent and a high-output, low-combustion-temperature gas generator composed thereof. Background Technology

[0002] In current torpedo designs, external gas cylinders provide pressure to force fuel from the fuel tank into the combustion chamber, ensuring stable combustion. However, external gas cylinders have drawbacks such as short lifespan, unstable pressure, large weight and volume, and high cost.

[0003] In this situation, the design concept of using a gas generator to replace the external gas cylinder emerged. The gas generator is installed outside the torpedo fuel tank and connected to the tank through a pipeline (or directly). When a ignition signal is received, it outputs high-pressure, low-temperature gas to provide a continuous and stable pressure to the torpedo fuel tank, ensuring reliable and stable combustion of the fuel.

[0004] To achieve this function, the gas generator's output gas must have characteristics such as low temperature, few impurities, high pressure output, and stable pressure. Summary of the Invention

[0005] One of the objectives of this invention is to provide a high-output, low-burning-rate gas-producing agent formulation to solve the above-mentioned problems.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a gas-generating agent, which is composed of the following raw materials in parts by weight:

[0007] 50-60 parts potassium nitrate

[0008] Azodiamide 33-43.5 parts

[0009] 0.5-1 part of ferrocene

[0010] 6 parts adhesive;

[0011] A total of 100 copies.

[0012] In the gas-generating agent of this invention, potassium nitrate is selected as the oxidant, which provides oxygen for the reaction when it decomposes upon heating; azodicarbonamide is selected as the reducing agent, which produces the corresponding compound and nitrogen gas during the reaction; ferrocene is a combustion rate regulating substance that can promote the combustion of the agent and regulate the combustion rate of the agent in the gas generator; the binder coats the various component materials in the agent, playing the role of bonding, fixing the components and passivating.

[0013] Potassium nitrate is a relatively stable and frequently used nitrate among nitrates. Before determining the preferred formulation of this application, sodium nitrate was used for testing. The results showed that the gas-generating agent mixed with sodium nitrate was more powerful, reacted faster, and had a higher instantaneous output pressure. However, sodium nitrate is more hygroscopic, which is not conducive to the storage of the agent. Therefore, potassium nitrate was finally selected as the raw material.

[0014] As a preferred technical solution, it is composed of the following raw materials in parts by weight:

[0015] Potassium nitrate 50 parts, azodicarbonamide 43.5 parts, ferrocene 0.5 parts, binder 6 parts, or

[0016] Potassium nitrate 60 parts, azodicarbonamide 33 parts, ferrocene 1.0 part, adhesive 6 parts.

[0017] As a preferred technical solution, all raw materials are of analytical grade.

[0018] As a preferred technical solution, the potassium nitrate particles are sieve blanks of 200 mesh, and the azodiamide particles are sieve blanks of 100 mesh. The smaller the particle size of the raw materials, the larger their specific surface area, and the easier they react during combustion; otherwise, if the particles are too coarse, the mixed reagent cannot burn.

[0019] As a preferred technical solution, the adhesive is fluororubber, and the adhesive is completely dissolved in acetone.

[0020] The second objective of this invention is to provide a high-output, low-combustion-temperature gas generator composed of the aforementioned gas-generating agent. The technical solution adopted is as follows: it includes an outer shell, an inner shell is provided inside the outer shell, and the gas-generating agent, a charge box, a filter and a filter screen are arranged sequentially from the center to the periphery inside the inner shell. A base and an electric ignition tube are provided at one end of the inner shell, and a nozzle is provided at the other end.

[0021] This invention improves the gas-generating agent by providing a high-output, low-burning-rate agent formulation, and also improves the structure of the gas generator to achieve a gas generator with low output gas temperature, few impurities, and stable output pressure.

[0022] As a preferred technical solution, the outer shell, inner shell, drug container, base, and nozzle are all steel structures. Preferably, they are manufactured by stamping and machining to ensure the stability of the product structure.

[0023] As a preferred technical solution, the electric ignition tube is an insensitive igniter, consisting of an electrical connector, ignition propellant, and a metal housing. It meets the requirement of 1A 1W 5min insensitivity without ignition, and upon receiving ignition energy, it can reliably ignite and ignite the gas-generating agent in the gas generator, while also meeting requirements for anti-static properties, stray current resistance, and electromagnetic radiation protection.

[0024] The base is preferably a metal part with sufficient strength and an electric ignition tube mounting interface.

[0025] The medication box is preferably a metal component that has both medication loading and gas release functions.

[0026] As a preferred technical solution, the filter agent is a mixture of calcium chloride and sodium carbonate in a 1:1 mass ratio, and is distributed around the perimeter of the drug container; the free bulk density of the gas-generating agent is (0.3~0.5) g·cm³. -3 .

[0027] The choice of free bulk density is crucial to ensuring the consistency of drug quality. If the bulk density is too high, there will be excess space inside the container, causing the drug to sway and reducing product safety. If the bulk density is too low, the drug must be compressed to maintain a constant dosage, which alters the gaps between the drug particles and the reaction rate.

[0028] The gas produced by the combustion of the propellant in the cartridge passes through a filter. The filter absorbs the moisture in the gas and cools it down. This ensures that the output gas from the gas generator is dry and at a low temperature, allowing it to maintain a stable pressure (if there is too much water vapor in the gas, the pressure will drop rapidly as the water vapor condenses during cooling).

[0029] As a preferred technical solution, the filter screen is a rigid filter screen, which is made by folding multiple layers of stamped metal mesh into a cylindrical shape, with a wall thickness of 2-6mm. The filter screen is used to filter various impurities in the combustion gas, ensuring the cleanliness of the gas.

[0030] Compared with the prior art, the advantages of the present invention are as follows: The present invention meets the requirements of torpedo fuel tanks for low temperature, low burning rate, few combustion impurities, and stable output pressure of output gas. It can achieve the following: gas temperature in the cavity ≤80℃, gas water solubility ≤5%, and impurity particle diameter in the gas ≤5μm. It fills the gap in the output of low temperature and low burning rate gas by gas generators and solves the problem of large volume and weight of external gas cylinders in torpedoes. Attached Figure Description

[0031] Figure 1 This is a structural diagram of the gas generator according to Embodiment 1 of the present invention;

[0032] Figure 2 This is the ignition pressure-time curve of Embodiment 1 of the present invention;

[0033] Figure 3 This is the ignition pressure-time curve of Embodiment 2 of the present invention;

[0034] Figure 4This is the ignition pressure-time curve for Comparative Example 1 of the present invention;

[0035] Figure 5 for Figure 1 Structural diagram of the medicine box.

[0036] In the diagram: 1. Outer shell; 2. Inner shell; 3. Gas-generating agent; 4. Nozzle; 5. Filter; 6. Filter screen; 7. Base; 8. Electric ignition tube; 9. Container. Detailed Implementation

[0037] The invention will now be further described with reference to the accompanying drawings. Example

[0038] A gas generator, see Figure 1 It includes an outer shell 1, an inner shell 2 inside the outer shell 1, and the gas-generating agent 3, the drug box 9, the filter 5 and the filter screen 6 arranged sequentially from the center to the periphery inside the inner shell 2. A base 7 and an electric ignition tube 8 are provided at one end of the inner shell 2, and a nozzle 4 is provided at the other end.

[0039] In this embodiment, the outer shell 1, inner shell 2, propellant box 9, base 7, and nozzle 4 are all steel structures, manufactured by stamping and machining. The inner shell 2 is provided with air holes. The electric ignition tube 8 is a desensitizing igniter, composed of an electrical connector, ignition propellant (the ignition propellant uses the existing known boron-potassium nitrate, i.e., BPN), and a metal shell, meeting the requirement of no ignition for 1A1W5min. The tensile strength σb of the material used for the base 7 is ≥630MPa, and it is a metal part for mounting the electric ignition tube interface. The propellant box is a metal part with the functions of propellant loading and gas venting. The filter screen 6 is a rigid filter screen, which is formed by folding multiple layers of stamped metal mesh into a cylindrical shape with a wall thickness of about 4mm. It is used to filter various impurities in the combustion gas to ensure the cleanliness of the gas.

[0040] In this embodiment, the filter agent is a mixture of calcium chloride and sodium carbonate in a 1:1 mass ratio, distributed around the perimeter of the medicine box 9.

[0041] In this embodiment, the drug container 9 is a ring-shaped metal part with a certain number of small holes on its side. During use, the holes are sealed with aluminum foil. During combustion, the gas breaks through the aluminum foil, releasing the gas. Figure 5 As shown.

[0042] Currently, common coolants are metal oxide particles (such as alumina) or substances that decompose easily upon heating (sodium bicarbonate). However, these common coolants cannot meet the operating conditions of this invention. The specific reasons are shown in Table 1:

[0043] Table 1. Performance Comparison of Different Coolants

[0044]

[0045] In this embodiment, the formulation of gas-generating agent 3 is as follows (by weight):

[0046] Potassium nitrate 50 parts, azodicarbonamide 43.5 parts, ferrocene 0.5 parts, binder 6 parts;

[0047] The potassium nitrate was of analytical grade and passed through a 200-mesh standard sieve; the azodicarbonamide was of analytical grade and passed through a 100-mesh standard sieve, conforming to standard HG / T 2097-2017; and the ferrocene was of analytical grade. The binder was completely dissolved in analytical grade acetone.

[0048] After weighing the above raw materials, dry mix them by passing them through a 40-mesh sieve at least six times. Add the dry mix to the mixing drum, add the dissolved binder, clean the container holding the binder with acetone, and add the cleaning solution to the mixing drum. Turn on the mixing drum and run it for at least 20 minutes. After discharging, wait until the wet-mixed agent is almost completely dry before granulating it. (After granulation, first air dry it at room temperature for about 1 hour, and then put it into a 50℃ oven to dry for more than 4 hours.)

[0049] After granulation, it is loaded into Figure 1 The Pt test was performed in the gas generator according to GJB5309.24 "Test Methods for Pyrotechnics - Part 24: Determination of Ignition Pressure-Time Curve". The testing instrument used was a dynamic signal test analyzer (signal DH5960). The obtained curve is shown below. Figure 2 As shown;

[0050] The working process of the gas generator of the present invention is as follows: the electric ignition tube 8 ignites the gas-generating agent 3 → the gas-generating agent 3 releases a large amount of gas after combustion → the gas enters the filter 5 through the charging box 9 → the filter 5 absorbs water vapor in the gas and reduces the gas temperature → the gas passes through the filter screen 6 to filter impurities → it enters the outer shell 1 through the air holes of the inner shell 2 → the gas is released from the nozzle 4. Figure 1 In the diagram, the arrow pointing to the direction marked L indicates the gas path;

[0051] Using the technical solution of this embodiment, after testing, it was found that: the gas temperature inside the cavity is ≤80℃; the gas water solubility rate (the gas solubility rate is determined by the closed method, which involves sealing a certain amount of gas and a certain amount of liquid together in a container; the solubility rate of the gas in the liquid is calculated by measuring the mass, volume and temperature change of the gas and solution inside the container) is ≤5%; and the diameter of impurity particles in the gas is ≤5μm.

[0052] Example 2:

[0053] Compared with Example 1, the only difference in this embodiment is the formulation of gas-generating agent 3. The formulation of gas-generating agent 3 in this embodiment is as follows (by weight):

[0054] Potassium nitrate 60 parts, azodicarbonamide 33 parts, ferrocene 1.0 part, adhesive 6 parts.

[0055] The Pt test was performed using the same method as in Example 1, and the results are as follows: Figure 3 As shown.

[0056] Comparative Example 1

[0057] Compared with Example 1, this comparative example only differs in that the gas-generating agent 3 uses a common gas generator agent (black powder), and its formulation is as follows by weight:

[0058] Potassium nitrate 75 parts, sulfur 10 parts, charcoal 15 parts;

[0059] The Pt test was performed using the same method as in Example 1, and the results are as follows: Figure 4 As shown.

[0060] Table 2 Comparison of Output Pressure Results of Different Examples / Comparative Examples

[0061]

[0062] As can be seen from the comparison in the table above, for the peak pressure of Examples 1 and 2, the peak pressure of Example 2 decreased by 47% due to the reduction of the azodicarbonamide content, indicating that an appropriate ratio can increase the output of the agent; for the peak pressure time of Examples 1 and 2, the peak pressure time of Example 2 decreased due to the increase of the ferrocene content, indicating that ferrocene has the function of accelerating the agent reaction; the peak pressure time and the pressure 900ms after the peak in Comparative Example 1 indicate that the agent formulation of Example 1 has advantages such as low burning rate and long pressure holding time.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-output, low-combustion-temperature gas generator, characterized in that, It includes an outer shell (1), inside which is an inner shell (2). Inside the inner shell (2), from the center outwards, are arranged a gas-generating agent (3), a drug container (9), a filter (5), and a filter screen (6). At one end of the inner shell (2) are a base (7) and an electric ignition tube (8), and at the other end is a nozzle (4). The gas-generating agent (3) is composed of the following raw materials in parts by weight: 50-60 parts potassium nitrate Azodiamide 33-43.5 parts 0.5-1 part of ferrocene 6 parts adhesive; A total of 100 copies; The filter agent (5) is a mixture of calcium chloride and sodium carbonate in a 1:1 mass ratio and is distributed around the perimeter of the drug container (9); the free bulk density of the gas-generating agent (3) is (0.3~0.5) g / cm³. 3 .

2. The gas generator according to claim 1, characterized in that, The gas-generating agent (3) is composed of the following raw materials in parts by weight: Potassium nitrate 50 parts, azodicarbonamide 43.5 parts, ferrocene 0.5 parts, binder 6 parts, or Potassium nitrate 60 parts, azodicarbonamide 33 parts, ferrocene 1.0 part, adhesive 6 parts.

3. The gas generator according to claim 1, characterized in that, The raw materials of the gas-generating agent (3) are all of analytical grade.

4. The gas generator according to claim 1, characterized in that, The potassium nitrate particles are sieve blanks with a particle size of 200 mesh, and the azodiamide particles are sieve blanks with a particle size of 100 mesh.

5. The gas generator according to claim 1, characterized in that, The adhesive is fluororubber, and the adhesive is completely dissolved in acetone.

6. The gas generator according to claim 1, characterized in that, The outer shell (1), inner shell (2), medicine box (9), base (7) and nozzle (4) are all steel structures.

7. The gas generator according to claim 1, characterized in that, The electric ignition tube (8) is an insensitive igniter, consisting of an electrical connector, ignition powder, and a metal housing.

8. The gas generator according to claim 1, characterized in that, The filter screen (6) is a rigid filter screen, which is formed by folding multiple layers of stamped metal screen into a cylindrical shape, with a wall thickness of 2-6mm.

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