A method for testing the long-term storage stability of explosives

Abstract

This invention provides a method for testing the long-term storage stability of explosives, comprising the following steps: Step 1, preparation of explosive samples; Step 2, rapid screening test; Step 3, setting of test conditions; Step 4, sample loading; Step 5, high-temperature isothermal test and pressure monitoring: the reactor containing the explosive samples is simultaneously placed in the reactor heating chamber of a stability testing system pre-controlled at a preset test temperature for isothermal holding test, while the pressure measurement module of the stability testing system dynamically monitors the gas pressure generated by the thermal decomposition of the sample to obtain a pressure-time curve; Step 6, data processing: the long-term storage stability test data are processed according to P=P t - P1 Formula Processing; Step Seven, Long-Term Storage Stability Evaluation. The method of this invention can evaluate the stability of solid explosives during storage and use, solving the problems of the lack of stability evaluation methods for solid explosives during storage and use, and the large errors in the evaluation of long-term storage stability by existing methods.

Description

Technical Field

[0001] This invention belongs to the field of explosives technology and relates to the performance testing of explosives, specifically to a method for testing the long-term storage stability of explosives. Background Technology

[0002] Explosives are one of the power and destructive energy sources for various weapon systems, widely used in guns, missiles, and rocket systems. During long-term storage, under various environmental stresses, the explosive charge itself and its components undergo slow physical and chemical changes. These changes may lead to decreased stability of the explosive charge during storage, causing changes in the charge structure and performance, and even combustion or explosion accidents. The stability of explosives is a crucial indicator, a vital parameter for evaluating the safety of explosives research, production, storage, and use. It can predict, prevent, and avoid accidents during use and storage, and has significant guiding significance for the manufacture, storage, and use of explosives.

[0003] Long-term storage stability refers to the ability of explosives to maintain their physical and chemical properties within permissible ranges under the influence of storage and usage environment and time effects during storage and use. In testing and evaluation, to shorten the test cycle, and while ensuring the consistency of the performance change mechanism, the test is generally conducted by appropriately increasing the ambient temperature, and the test sample should not change its properties (including phase state, particle size, etc.). Existing methods for testing the chemical stability of explosives mainly evaluate it through qualitative and quantitative detection of gaseous products, condensed products, and enthalpy from the decomposition of explosives. These include the pressure sensor method for vacuum stability testing in GJB772B-2022 Explosives Test Method 501.2; the Vieri method for stability and the methyl violet method for stability in GJB 770B-2022 Explosives Test Method 503.1; and differential thermal analysis and differential scanning calorimetry for stability and compatibility in GJB772B-2022 Explosives Test Method 501.2. Both the GJB772B-2022 Explosives Test Method 501.2 Vacuum Stability Test Pressure Sensor Method and this invention are based on the gas pressure generated by the decomposition of explosives. The GJB772B-2022 Explosives Test Method 501.2 Vacuum Stability Test Pressure Sensor Method involves loading a quantitative (5g or 1g) sample of explosive into a sealed reactor, maintaining a vacuum state, and heating it at 90℃, 100℃, or 120℃ for 48 hours. The chemical stability is evaluated by the volume of gas released from the sample under standard conditions. This method is mainly used for stability evaluation, comparison of the stability of different materials, and screening.

[0004] Existing vacuum stability tests use samples under vacuum conditions, which does not match the actual storage and use environment of explosives. This ignores the influence of the ambient atmosphere (water vapor, oxygen, etc.) on the stability of explosives, potentially greatly increasing the probability of misjudging long-term storage stability. Furthermore, existing vacuum stability testing methods calculate the volume of gas produced per gram of sample under standard conditions through the gas law. This calculation is affected by system volume, temperature, and pressure. Moreover, research has shown that the amount of sample does not correlate proportionally with the volume of gas produced during decomposition; therefore, calculating the standard-state gas volume per gram of sample may contain significant errors. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for testing the long-term storage stability of explosives, thereby solving the technical problem that the error in existing long-term storage stability evaluation methods needs to be further reduced.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for testing the long-term storage stability of explosives, the method comprising the following steps: Step 1: Preparation of explosive samples.

[0007] Step 2, rapid screening test: Differential thermal analysis and differential scanning calorimetry were used to conduct rapid screening tests on the thermal decomposition of the explosive samples to determine the melting temperature, thermal decomposition initiation temperature and decomposition peak temperature of the samples.

[0008] Step 3, setting up experimental conditions: Based on the melting temperature, thermal decomposition initiation temperature, and decomposition peak temperature of the sample to be tested obtained in step two, the long-term storage stability test conditions are set according to the characteristics of the sample to be tested.

[0009] The characteristics of the samples to be tested include single-base gunpowder, double-base gunpowder, triple-base gunpowder, composite solid propellants, and explosives.

[0010] The long-term storage stability test conditions include the test temperature and the holding time.

[0011] Step 4, Sample loading: Accurately weigh 1g of the explosive sample prepared in step one, put it into the reactor of the long-term storage stability test system for explosives and seal it. Record the ambient temperature and humidity during the test filling. At the same test temperature, at least two parallel explosive samples need to be filled.

[0012] Step 5: High-temperature constant temperature test and pressure monitoring: The reactors filled with explosive samples were simultaneously placed in the reactor heating chamber of the stability testing system, which was kept constant at the preset test temperature, at the same test temperature for a constant temperature and heat preservation test. At the same time, the pressure measurement module of the stability testing system was used to dynamically monitor the gas pressure generated by the thermal decomposition of the sample and obtain the pressure-time curve.

[0013] Step Six, Data Processing: Long-term storage stability test data are calculated according to P=P t -P1 formula processing: among the measurement data of at least two parallel explosive samples, the maximum value is taken as the measurement result; In the formula: P represents the gas pressure value generated by the decomposition of the explosive sample; P t This indicates the pressure value in the reactor when the explosive sample reaches the constant temperature holding time t. P1 represents the pressure value in the reactor when the explosive sample is heated for 1 hour.

[0014] Step 7, Long-term storage stability evaluation: Using the stability threshold Pc as the evaluation criterion, when the gas pressure value P generated by the decomposition of the explosive sample is less than or equal to Pc, the long-term storage stability is qualified; otherwise, the long-term storage stability is unqualified.

[0015] The present invention also has the following technical features: In step one, the explosive sample must meet the following requirements: First, larger-sized explosives are pulverized into particles that can pass through a 5.0mm sieve, while smaller particles that pass through a 0.2mm sieve are removed.

[0016] Second, for explosive samples that can pass through a 5.0mm sieve without requiring crushing, the original samples were tested.

[0017] Third, the solid explosive samples used in the experiment were not artificially dried to ensure that the experimental conditions were consistent with the actual long-term storage conditions.

[0018] In step three, the test temperature for single-base propellant is set at 125℃ and the holding time is set at 4.5h; the test temperature for double-base propellant, triple-base propellant, composite solid propellant, and explosive is set at 110℃ and the holding time is set at 6h.

[0019] In step four, the error should not exceed 0.001g.

[0020] In step four, the long-term storage stability test system for explosives includes a pressure measurement module. The pressure measurement module includes at least one reactor and at least one pressure measurement transmission tube. One end of each pressure measurement transmission tube is connected to the gas outlet at the top of the reactor, and the other end of each pressure measurement transmission tube is connected to the measurement port of a pressure sensor.

[0021] It also includes a constant temperature heating module, which includes an outer shell, an inner stainless steel sleeve, a furnace support plate at the bottom of the stainless steel sleeve, a furnace body mounted on the furnace support plate via a furnace body bracket, a heater for heating the furnace body mounted on the furnace support plate, and at least one reactor heating chamber installed inside the furnace body. Each reactor heating chamber is coaxially provided with a movable insulation sleeve, the top of which extends to the top of the outer shell. The reactor can enter the reactor heating chamber through the movable insulation sleeve and be heated by the constant temperature heating module.

[0022] Compared with the prior art, the present invention has the following technical effects: (I) The method of the present invention can evaluate the stability of solid explosives during storage and use, and solves the problems of lack of stability evaluation methods for solid explosives during storage and use and large errors in the evaluation of long-term storage stability of existing methods.

[0023] (II) Based on real storage and use environment conditions, this invention evaluates long-term storage stability by directly monitoring the gas pressure generated by the decomposition of explosives under limited increase in storage environment temperature. The test conditions are more scientific and reasonable, improving the accuracy of test results. At the same time, the method is simple to operate, the test process is fully automated, and the requirements for experimental personnel are low. Attached Figure Description

[0024] Figure 1 This is a procedure for testing the long-term storage stability of explosives.

[0025] Figure 2 yes Figure 1 Pressure-time curves of typical explosive samples at 110℃ in the method.

[0026] Figure 3 This is the pressure-time curve of sample A explosive No. 1 at 110℃ in the application example.

[0027] Figure 4 This is the pressure-time curve of explosive sample No. 2 in the application example at 110℃.

[0028] Figure 5 This is a schematic diagram of the overall structure of the long-term storage stability testing system for explosives.

[0029] Figure 6This is a schematic diagram of the internal structure of a long-term storage stability testing system for explosives.

[0030] Figure 7 This is a schematic diagram of the overall structure of the reactor.

[0031] Figure 8 This is a schematic diagram of the gas pressure measurement transmission tube.

[0032] Figure 9 A schematic diagram showing the connection between the gas pressure measurement transmission tube, the reactor, and the pressure sensor.

[0033] Figure 10 This is a schematic diagram of the external structure of the movable insulation sleeve.

[0034] Figure 11 This is a schematic diagram of the internal structure of the movable insulation sleeve.

[0035] The meanings of the labels in the diagram are as follows: 1-reactor, 2-pressure measurement and transmission pipe, 3-pressure sensor, 4-outer shell, 5-furnace support, 6-furnace body, 7-heater, 8-reactor heating chamber, 9-movable insulation sleeve, 10-glass fiber outer insulation cylinder, 11-glass fiber inner insulation cylinder, 12-stainless steel sleeve, 13-top ceramic insulation plate, 14-furnace body support plate.

[0036] 101-Volume reaction tube, 102-Fastening nut, 103-Gas guide head, 104-Sealing ring, 105-Capillary pressure transmission tube, 106-Reinforcing layer, 107-Heat sink, 108-Connecting hole, 109-Fastening screw.

[0037] 201-Pressure transmission sleeve, 202-Pressure probe, 203-Connector, 204-Connecting nut, 205-Protective sleeve, 206-Sheath tube, 207-Screw.

[0038] 901-Fixed base, 902-Insulation sleeve, 903-Metal cover, 904-Annular heat insulation cover, 905-Reactor through cavity.

[0039] 90101 - Inner cylinder, 90102 - Annular support base.

[0040] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, all devices and methods in this invention employ those known in the prior art.

[0042] Based on extensive research, this invention proposes a method for testing the long-term storage stability of explosives using dynamic pressure monitoring. This method is suitable for evaluating the long-term storage stability and safe storage life of solid explosives. A key advantage of this invention is that it evaluates long-term storage stability directly by monitoring the gas pressure generated during the decomposition of explosives under realistic storage and usage conditions, with limited increases in storage temperature. This results in more scientific and reasonable test conditions, improved accuracy of test results, and a solution to the problems in long-term storage stability testing methods for explosives.

[0043] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0044] Example: This embodiment provides a method for testing the long-term storage stability of explosives, such as... Figure 1 As shown, the method includes the following steps: Step 1, Preparation of explosive samples: In step one, the explosive sample has the following requirements: First, larger-sized explosives are pulverized into particles that can pass through a 5.0mm sieve, while smaller particles that pass through a 0.2mm sieve are removed.

[0045] Second, for explosive samples that can pass through a 5.0mm sieve without requiring crushing, the original samples were tested.

[0046] Third, the solid explosive samples used in the experiment were not artificially dried to ensure that the experimental conditions were consistent with the actual long-term storage conditions.

[0047] Step 2, rapid screening test: Differential thermal analysis and differential scanning calorimetry were used to conduct rapid screening tests on the thermal decomposition of the explosive samples to determine the melting temperature, thermal decomposition initiation temperature and decomposition peak temperature of the samples; this provides a basis for setting long-term storage stability test conditions.

[0048] In this embodiment, differential thermal analysis and differential scanning calorimetry are employed using differential thermal analysis and differential scanning calorimetry known in the art.

[0049] Step 3, setting up experimental conditions: Based on the melting temperature, thermal decomposition initiation temperature, and decomposition peak temperature of the sample to be tested obtained in step two, the long-term storage stability test conditions are set according to the characteristics of the sample to be tested.

[0050] The characteristics of the samples to be tested include single-base gunpowder, double-base gunpowder, triple-base gunpowder, composite solid propellants, and explosives.

[0051] The long-term storage stability test conditions include the test temperature and the holding time.

[0052] In step three, the test temperature for single-base propellant is set at 125℃ and the holding time is set at 4.5h; the test temperature for double-base propellant, triple-base propellant, composite solid propellant, and explosive is set at 110℃ and the holding time is set at 6h.

[0053] Step 4, Sample loading: Accurately weigh 1g of the explosive sample prepared in step one, put it into the reactor of the long-term storage stability test system for explosives and seal it. Record the ambient temperature and humidity during the test filling. At the same test temperature, at least two parallel explosive samples need to be filled.

[0054] In step four, the error should not exceed 0.001g.

[0055] As a preferred embodiment, the long-term storage stability testing system for explosives in step four, such as... Figure 5 As shown, it includes a pressure measurement module, which includes at least one reactor 1 and at least one pressure measurement transmission tube 2. One end of each pressure measurement transmission tube 2 is connected to the air outlet at the upper end of the reactor 1, and the other end of each pressure measurement transmission tube 2 is connected to the measurement port of the pressure sensor 3.

[0056] like Figure 6 As shown, it also includes a constant temperature heating module, which includes a housing 4, inside which is fitted a stainless steel sleeve 12. A furnace support plate 14 is provided at the bottom of the stainless steel sleeve 12. A furnace body 6 is installed on the furnace support plate 14 via a furnace body bracket 5. A heater 7 for heating the furnace body 6 is installed on the furnace support plate 14. At least one reactor heating chamber 8 is installed inside the furnace body 6. A movable insulation sleeve 9 is coaxially provided on each reactor heating chamber 8. The top of the movable insulation sleeve 9 extends to the top of the housing 4. The reactor 1 can enter the reactor heating chamber 8 through the movable insulation sleeve 9 and be heated by the constant temperature heating module.

[0057] As one specific solution in this embodiment, such as Figure 7 As shown, reactor 1 includes a top-open constant-volume reaction tube 101. A gas guide head 103 is covered by a fastening nut 102 at the opening of the constant-volume reaction tube 101. Sealing rings 104 are respectively provided between the constant-volume reaction tube 101 and the fastening nut 102 and between the constant-volume reaction tube 101 and the gas guide head 103. The gas guide head 103 is connected to the lower end of the capillary pressure transmission tube 105. The upper end of the capillary pressure transmission tube 105 is connected to one end of the pressure measurement transmission tube 2. The capillary pressure transmission tube 105 is covered with a reinforcing layer 106. The upper section of the reinforcing layer 106 is set as a heat sink 107.

[0058] In this embodiment, the constant volume reaction tube 101 is cylindrical with an inner diameter of 8.5 mm, an outer diameter of 20 mm, a height of 110 mm, a bottom thickness of 2 mm, and an internal volume of 25 ml ± 0.5 ml, and is used to hold the explosive sample.

[0059] In this embodiment, the fastening nut 102 is hexagonal on the outside and is used to connect the constant volume reaction tube 101 and the gas guide head 103. The constant volume reaction tube 101 is pre-fitted with a locking screw 109, and the locking screw 109 and the fastening nut 102 are locked together by thread engagement.

[0060] In this embodiment, the sealing ring 104 is annular and is used for sealing between the two.

[0061] In this embodiment, the upper end of the capillary pressure transmission tube 105 is provided with an external thread, which facilitates threaded connection with the connecting nut 204 at one end of the pressure measurement transmission tube 2.

[0062] In this embodiment, the reinforcing layer 106 is welded to the outside of the capillary pressure conduction tube 105 to protect the capillary pressure conduction tube 105. The upper half of the reinforcing layer 106 is a heat sink 107 for heat dissipation of the capillary pressure conduction tube 105.

[0063] As a preferred embodiment of this invention, such as Figure 7 As shown, a connecting hole 108 is radially formed on the sidewall of the reinforcing layer 106 between the heat sinks 107. In this embodiment, the connecting hole 108 is used to prevent the formation of a sealed structure between the reinforcing layer 106 and the capillary pressure conduction tube 105, which could lead to damage to the capillary pressure conduction tube 105 due to thermal expansion and contraction of the gas.

[0064] In this embodiment, the constant volume reaction tube 101, fastening nut 102, capillary pressure transmission tube 105, reinforcing layer 106 and heat sink 107 are made of stainless steel; the sealing ring 104 is made of fluororubber or soft aluminum.

[0065] In this preferred embodiment, the outer shell 4 is provided with a placement seat for placing the reactor 1, which is used to place the reactor 1 when the reactor 1 is not heated.

[0066] The reactor of this invention can ensure that there is sufficient space for dangerous samples such as explosives during the test process, and has good sealing performance, which can ensure that the gas released from the constant temperature decomposition of the sample is completely discharged to the pressure measurement module.

[0067] The internal volume of the reactor in this invention is determined by constant volume, ensuring that the test results are comparable to those of the traditional gas measurement method.

[0068] The reinforced structure and spiral heat dissipation structure of the reactor design of this invention can ensure gas conduction while reducing stress at the weld joints, extending the service life of the reactor, and improving the connection efficiency between the reactor and the pressure measurement module.

[0069] As one specific solution in this embodiment, such as Figure 8 As shown, the pressure measurement transmission tube 2 includes a hollow pressure transmission sleeve 201. One end of the pressure transmission sleeve 201 is connected to the pressure measuring head 202, and the other end of the pressure transmission sleeve 201 is connected to the connector 203. The connector 203 is fitted with a connecting nut 204.

[0070] like Figure 9 As shown, the lower end of the pressure measuring head 202 is provided with an external thread; the pressure measuring head 202 is connected to the measuring port of the pressure sensor 3 by a thread; the connecting nut 204 is connected to and sealed to the air outlet at the upper end of the reactor 1 by a thread.

[0071] In this embodiment, the pressure transmission sleeve 201 is a 316 stainless steel microporous metal tube with an outer diameter of 1.588 mm, a wall thickness of 0.508 mm, a length of 400.0 mm, and a volume of approximately 0.103 mL. Its pore size and volume are much smaller than the inner diameter of reactor 1, which is approximately 17 mm, and its volume is approximately 25 mL. Through laser precision welding, a pressure measuring head 202 is welded to one end of the pressure transmission sleeve 201, and a connector 203 is welded to the other end.

[0072] In this embodiment, a connecting pipe is provided outside the upper through hole of the pressure measuring head 202. The outer diameter and wall thickness are the same as those of the pressure transmission sleeve 201, and it is connected to the port of the pressure transmission sleeve 201 by welding.

[0073] In this embodiment, the connector 203 is a stainless steel cylinder with a through hole. The through hole is divided into upper and lower parts. The upper part of the through hole has the same diameter as the inner diameter of the pressure transmission sleeve 201, while the lower part has a slightly larger diameter. This allows it to fit tightly with the upper outlet of the reactor 1 and be sealed by the connecting nut 204. A connecting pipe is provided outside the through hole at the upper end of the cylinder. The inner and outer diameters of the pipe are the same as those of the pressure transmission sleeve 201, and the pipe is connected to the other end of the pressure transmission sleeve 201 by laser welding.

[0074] In this embodiment, the connecting nut 204 is a standard part. When welding the connector 203, the connecting nut 204 must first be fitted onto the outside of the pressure transmission sleeve 201. The connecting nut 204 is connected through the external thread of the gas outlet end of the reactor 1.

[0075] As a preferred embodiment of this invention, such as Figure 8As shown, the pressure transmission ferrule 201 is covered with a protective sleeve 205, which is a polytetrafluoroethylene (PTFE) tube. In this embodiment, the protective sleeve 205 is used to protect the metal pressure transmission ferrule 201 from deformation and breakage under external force or bending. The inner diameter of the protective sleeve 205 is slightly larger than the outer diameter of the ferrule, approximately 2 mm, and the outer diameter is 4 mm. Its length is the same as that of the pressure transmission ferrule 201, which is 400 mm. When welding the pressure measuring head 202 and the connector 203, the PTFE protective sleeve 205 must first be fitted onto the pressure transmission ferrule 201.

[0076] As a preferred embodiment of this invention, such as Figure 8 As shown, a protective sleeve 206 is installed at the connection position between the pressure transmission sleeve 201 and the pressure probe 202, and at the connection position between the pressure transmission sleeve 201 and the connector 203. The protective sleeve 206 is a stainless steel metal tube.

[0077] In this embodiment, since the wall thickness of the microporous metal pressure transmission sleeve 201 is relatively thin, about 0.508 mm, and the welded part is relatively weak, a protective sleeve 206 is installed at each of the welded parts at both ends of the pressure transmission sleeve 201; the pressure measuring head 202 is a stainless steel external hexagonal threaded through-hole connector, and the inner diameter of its through hole is consistent with the inner diameter of the pressure transmission sleeve 201.

[0078] In this embodiment, the outer diameter of the sheath tube 206 is 10mm, and its inner diameter is the same as the outer diameter of the protective sleeve 205, which is 4mm. It is fixed to the welding parts at both ends of the pressure transmission sleeve tube 201 by four embedded screws 207 to protect the welding parts from external bending.

[0079] The pressure measurement transmission tube of the present invention has a slender microporous structure, is covered with a polytetrafluoroethylene protective sleeve, and is designed with heating and constant temperature control at its connection with the reactor. This effectively solves the problems of high temperature gas thermal diffusion affecting the measurement accuracy of high-precision pressure sensors, drastic fluctuations in ambient temperature affecting accurate gas pressure measurement, and phase transitions of explosive gas products affecting accurate pressure measurement, thereby improving the pressure measurement accuracy of the testing system.

[0080] The pressure measurement transmission tube of the present invention can accurately measure the pressure of high-temperature gas in the reactor of the test system to the room temperature environment outside the test system.

[0081] As a preferred embodiment, a temperature sensor is installed inside the furnace body 6; such as Figure 6As shown, the stainless steel sleeve 12 is filled with a glass fiber outer insulation cylinder 10, and a glass fiber inner insulation cylinder 11 is provided inside the glass fiber outer insulation cylinder 10. The height of the glass fiber inner insulation cylinder 11 is less than the height of the glass fiber outer insulation cylinder 10. The furnace body 6 is located inside the glass fiber inner insulation cylinder 11. A top ceramic heat insulation plate 13 is installed on the top of the glass fiber inner insulation cylinder 11 for thermal insulation. The top opening of the movable insulation sleeve 9 extends out of the top ceramic heat insulation plate 13.

[0082] As a preferred embodiment, the furnace body 6 has a symmetrical cylindrical structure and is made of cast aluminum; there are eight pressure measurement and transmission pipes 2; there are eight reactor heating chambers 8, which are evenly distributed inside the furnace body 6.

[0083] As a preferred embodiment of this invention, such as Figure 10 and Figure 11 As shown, the movable insulation sleeve 9 includes a fixing base 901, the fixing base 901 includes an inner cylinder 90101, and the bottom of the inner cylinder 90101 is coaxially and integrally formed with an annular support base 90102. The inner cylinder 90101 and the annular support base 90102 are vertically arranged.

[0084] like Figure 11 As shown, the inner cylinder 90101 is fitted with an insulation sleeve 902, and the insulation sleeve 902 is fitted with a metal cover 903. The bottom ends of the insulation sleeve 902 and the metal cover 903 are both resting on the annular support base 90102.

[0085] like Figure 11 As shown, the top of the inner cylinder 90101 is detachably fitted with an annular heat insulation cover 904. The central hole of the annular heat insulation cover 904, the central cavity of the inner cylinder 90101, and the central hole of the annular support base 90102 form a reactor through cavity 905 with both ends connected.

[0086] In this embodiment, the insulation sleeve 902 is made of gypsum material; the thickness of the insulation sleeve 902 is 21mm. For example... Figure 10 As shown, the metal cover 903 has a perforated mesh structure. The annular heat insulation cover 904 is made of ABS plastic material.

[0087] In this embodiment, the movable insulation sleeve 9 is assembled with the sealed reactor 1: the movable insulation sleeve 9 is inserted into the capillary pressure transmission tube 105 of the sealed reactor 1 from top to bottom, placed outside the capillary pressure transmission tube 105, and in contact with the upper part of the fastening nut 102. The fastening nut 102 also serves as a limiting device. After the movable insulation sleeve 9 is assembled, the upper end of the sealed reactor 1 can expose all the external threads, which are used for threaded connection between the capillary pressure transmission tube 105 of the sealed reactor 1 and the connecting nut 204 at one end of the pressure measuring transmission tube 2.

[0088] The movable insulation sleeve of this invention provides a dedicated movable insulation sleeve for a long-term storage stability tester for explosives. The movable insulation sleeve proposes various designs to improve the insulation performance of different components, while taking into account the requirements of overall strength, sealing, and convenience, and has good insulation effect and practicality.

[0089] The advantages of the movable insulation sleeve of the long-term storage stability tester for explosives proposed in this invention are: first, it matches well with the structure of a sealed reactor; second, it has a low heat transfer rate and good insulation effect; and third, it is movable, flexible to use, and convenient to maintain.

[0090] In the long-term storage stability test system for explosives of the present invention, the explosives are placed in the reactor 1 of the pressure measurement module during the test. The reactor 1 is heated to a given volume by the constant temperature heating module. The decomposition gas pressure value is transmitted to the remote pressure sensor 3 through the pressure measurement transmission tube 2. The temperature of the constant temperature heating module is controlled and the decomposition gas pressure value is recorded.

[0091] The system of the present invention can realize continuous dynamic monitoring of the decomposition process of explosives, obtain the thermal decomposition pressure curve of explosive products, and quantitatively test and evaluate the stability of explosives.

[0092] The system of this invention has a large sample size, which is representative; at the same time, the reaction space is closed, which ensures that the thermal decomposition gas products accumulate in the reaction space and is close to the actual storage and processing conditions, which can avoid the influence of the test environment on the test results and improve the accuracy of the stability evaluation results.

[0093] Step 5: High-temperature constant temperature test and pressure monitoring: The reactors filled with explosive samples were simultaneously placed in the reactor heating chamber 8 of the stability testing system, which was kept constant at the preset test temperature, at the same test temperature for a constant temperature insulation test. At the same time, the pressure measurement module of the stability testing system was used to dynamically monitor the gas pressure generated by the thermal decomposition of the sample and obtain the pressure-time curve.

[0094] In this embodiment, the pressure-time curve of a typical explosive sample at 110°C is shown below. Figure 2 As shown.

[0095] Step Six, Data Processing: Long-term storage stability test data are calculated according to P=P t -P1 formula processing: among the measurement data of at least two parallel explosive samples, the maximum value is taken as the measurement result; In the formula: P represents the gas pressure value generated by the decomposition of the explosive sample; P tThis indicates the pressure value in the reactor when the explosive sample reaches the constant temperature holding time t (4.5h or 6h); P1 represents the pressure value in the reactor when the explosive sample is heated for 1 hour.

[0096] Step 7, Long-term storage stability evaluation: Using the stability threshold Pc as the evaluation criterion, when the gas pressure value P generated by the decomposition of the explosive sample is less than or equal to Pc, the long-term storage stability is qualified; otherwise, the long-term storage stability is unqualified.

[0097] Application example: This application example provides a method for testing the long-term storage stability of explosives based on the above embodiments. This application example further details the present invention based on a certain explosive A.

[0098] Explosive A: A commonly used explosive known in the field, white with fine grains, median volumetric particle size of 10μm to 100μm, impact sensitivity of 40%, friction sensitivity of 40%, and stability: the gas pressure generated by decomposition at 110℃ within 5 hours is not greater than 15kPa / g.

[0099] The method includes the following steps: Step 1, Preparation of explosive samples: In step one, the explosive samples have the following requirements: Explosive A must be white, fine-grained, with a median particle size of 10μm to 100μm. If the sample's three-dimensional dimensions are less than 5mm, no pretreatment is required, and the original sample will be used for testing. The Explosive A samples used in the test will not be artificially dried to ensure that the test conditions are consistent with the actual long-term storage conditions. Friction and impact are strictly prohibited during the test; precautions must be taken to prevent combustion and explosion accidents.

[0100] Step 2, rapid screening test: Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) were used to conduct rapid thermal decomposition screening tests on the explosive samples under test. The DTC curves determined that the melting temperature of explosive A was 140℃–142℃, the thermal decomposition initiation temperature was 185℃, and the decomposition peak temperature was 204℃. These melting and decomposition temperatures of explosive A can serve as a basis for selecting and setting long-term storage stability test conditions.

[0101] Step 3, setting up experimental conditions: Through rapid screening tests, the melting temperature of explosive A was found to be 140℃~142℃, the thermal decomposition initiation temperature was 185℃, and the decomposition peak temperature was 204℃. Therefore, to ensure that the stability test results are not affected by changes in sample properties such as melting and volatilization, the test temperature for explosive A was set at 110℃, and the holding time was set at 6h.

[0102] The above test conditions were set on the long-term storage stability test system for explosives based on pressure dynamic monitoring. The constant temperature furnace of the test system was heated until the temperature stabilized at 110°C and was ready for use.

[0103] Step 4, Sample loading: Accurately weigh 1g of the prepared explosive A sample from step one, with an error not exceeding 0.001g. Place the sample into the reactor of the pressure dynamic monitoring explosive long-term storage stability test system and seal it. Pay attention to the fit and sealing of all joints in the reactor. Record the ambient temperature and humidity during the test loading. Load at least two parallel explosive samples (sample 1 and sample 2).

[0104] Step 5: High-temperature constant temperature test and pressure monitoring: The reactors containing the sealed samples were simultaneously placed into the reactor heating chamber 8 of the stability testing system, which was pre-set to a constant test temperature, for a constant temperature insulation test. Simultaneously, the pressure measurement module of the stability testing system was used to dynamically monitor the gas pressure generated by the thermal decomposition of samples 1 and 2, obtaining pressure-time curves as follows: Figure 3 and Figure 4 .

[0105] Step Six, Data Processing: Long-term storage stability test data are calculated according to P=P t -P1 formula processing, by Figure 3 It can be seen that the pressure in the reactor of sample A explosive No. 1 was 115.5 kPa after being kept at a constant temperature of 110℃ for 6 hours, and the pressure in the reactor was 104 kPa after being heated for 1 hour. Therefore, the pressure of the gas produced by the decomposition of sample A explosive No. 1 within 5 hours was 11.5 kPa. Figure 4 It can be seen that the pressure in the reactor of sample A explosive No. 2 was 112.5 kPa after being kept at a constant temperature of 110℃ for 6 hours, and the pressure in the reactor was 100.8 kPa after being heated for 1 hour. Therefore, the gas pressure P generated by the decomposition of sample A explosive No. 2 within 5 hours is 11.7 kPa. Among the measurement data of the two parallel-fired explosive samples No. 1 and No. 2, the maximum value is taken as the measurement result. Therefore, the gas pressure P generated by the decomposition of sample A explosive within 5 hours is 11.7 kPa.

[0106] Step 7, Long-term storage stability evaluation: Based on the stability threshold Pc, according to the product technical specifications, the stability threshold Pc for explosive A is that the gas pressure generated by the decomposition of 1g sample at 110℃ for 5 hours should not exceed 15kPa. The measured gas pressure P generated by the decomposition of 1g sample of explosive A at 110℃ for 5 hours was 11.7kPa, which did not exceed 15kPa.

Claims

1. A method for testing the long-term storage stability of explosives, characterized in that, The method includes the following steps: Step 1: Preparation of explosive samples; Step 2, rapid screening test: Differential thermal analysis and differential scanning calorimetry were used to conduct rapid screening tests on the thermal decomposition of the explosive samples to determine the melting temperature, thermal decomposition initiation temperature and decomposition peak temperature of the samples. Step 3, setting up experimental conditions: Based on the melting temperature, thermal decomposition initiation temperature and decomposition peak temperature of the sample to be tested obtained in step two, set the long-term storage stability test conditions according to the characteristics of the sample to be tested. The characteristics of the samples to be tested include single-base gunpowder, double-base gunpowder, triple-base gunpowder, composite solid propellants, and explosives; The long-term storage stability test conditions include the test temperature and the holding time; In step three, the test temperature for single-base gunpowder is set to 125℃ and the holding time is set to 4.5h; the test temperature for double-base gunpowder, triple-base gunpowder, composite solid propellant and explosive is set to 110℃ and the holding time is set to 6h. Step 4, Sample loading: Accurately weigh 1g of the explosive sample prepared in step one, put it into the reactor (1) of the explosive long-term storage stability test system and seal it. Record the ambient temperature and humidity during the test filling. At the same test temperature, no less than two parallel explosive samples need to be filled. Step 5: High-temperature constant temperature test and pressure monitoring: The reactor (1) filled with explosive samples was placed in the reactor heating chamber (8) of the stability test system, which was kept constant at the preset test temperature, at the same test temperature. The constant temperature heat preservation test was carried out. At the same time, the pressure measurement module of the stability test system was used to dynamically monitor the gas pressure generated by the thermal decomposition of the sample and obtain the pressure-time curve. Step Six, Data Processing: Long-term storage stability test data are calculated according to P=P t -P1 formula processing: among the measurement data of at least two parallel explosive samples, the maximum value is taken as the measurement result; In the formula: P represents the gas pressure value generated by the decomposition of the explosive sample; P t This indicates the pressure value in the reactor when the explosive sample reaches the constant temperature holding time t. P1 represents the pressure value in the reactor after the explosive sample has been heated for 1 hour; Step 7, Long-term storage stability evaluation: Using the stability threshold Pc as the evaluation criterion, when the gas pressure value P generated by the decomposition of the explosive sample is less than or equal to Pc, the long-term storage stability is qualified; otherwise, the long-term storage stability is unqualified.

2. The method for testing the long-term storage stability of explosives as described in claim 1, characterized in that, In step one, the explosive sample must meet the following requirements: First, larger-sized explosives are pulverized into particles that can pass through a 5.0mm sieve, while smaller particles that pass through a 0.2mm sieve are removed. Second, for explosive samples that can pass through a 5.0mm sieve without needing to be crushed, the original samples will be tested. Third, the solid explosive samples used in the experiment were not artificially dried to ensure that the experimental conditions were consistent with the actual long-term storage conditions.

3. The method for testing the long-term storage stability of explosives as described in claim 1, characterized in that, In step four, the error should not exceed 0.001g.

4. The method for testing the long-term storage stability of explosives as described in claim 1, characterized in that, In step four, the long-term storage stability test system for explosives includes a pressure measurement module. The pressure measurement module includes at least one reactor (1) and at least one pressure measurement transmission tube (2). One end of each pressure measurement transmission tube (2) is connected to the air outlet at the upper end of the reactor (1), and the other end of each pressure measurement transmission tube (2) is connected to the measurement port of the pressure sensor (3). It also includes a constant temperature heating module, which includes a shell (4), a stainless steel sleeve (12) is fitted inside the shell (4), a furnace support plate (14) is provided at the bottom of the stainless steel sleeve (12), a furnace body (6) is installed on the furnace support plate (14) through a furnace body bracket (5), a heater (7) for heating the furnace body (6) is installed on the furnace support plate (14), at least one reactor heating chamber (8) is installed inside the furnace body (6), and a movable heat insulation sleeve (9) is coaxially provided on each reactor heating chamber (8), the top of the movable heat insulation sleeve (9) extends to the top of the shell (4); the reactor (1) can enter the reactor heating chamber (8) through the movable heat insulation sleeve (9) and be heated by the constant temperature heating module.

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