A friction energy testing instrument and method

Abstract

This invention discloses a friction energy tester and method. The friction energy tester includes a friction device, a worktable, a hot air blower, a hot air chamber, a camera, and a gas measurement sensor. The friction device is mounted on a base on the top surface of the worktable and includes a frame, an eccentric cam linkage mechanism, a servo motor, a bracket, a ceramic plate, a connecting frame, a counterweight, a weight arm, weights, and a ceramic rod. The hot air blower is located on the lower layer of the worktable and is connected to an air inlet pipe and a hot air pipe, which extends upwards to the hot air chamber for controlling the test temperature of the sample. The gas measurement sensor is located at the air outlet of the hot air chamber. The camera can observe the state of the sample. The test endpoint is determined by the camera observation and the gas measurement sensor. After the test, the friction energy of the sample is calculated according to the friction energy conversion formula. This invention can realize the friction energy testing of explosives in the field of energetic materials, slurries, tablets, etc.

Description

Technical Field

[0001] This invention belongs to the technical field of testing friction energy of energetic materials, slurries, tablets and other explosives in the field of solid propellants. It relates to a friction energy tester and method, which can identify, classify and conduct safety assessments of solid propellants and process materials prepared by new materials, new processes, new formulations and new methods. Background Technology

[0002] Solid propellants and process materials are characterized by high energy, high risk, and high mechanical sensitivity. During the research, trial production, manufacturing, and application processes, friction inevitably occurs to varying degrees between materials, and between materials and equipment or tooling. This friction can lead to unpredictable combustion and explosion accidents due to the instantaneous accumulation of energy. Especially for solid propellants and process materials involving new materials, processes, formulations, and methods, frictional energy testing is essential to determine whether the materials are too dangerous to be produced or transported in the manner described in the test.

[0003] Currently, research on testing devices and methods for the friction sensitivity of explosives has been conducted both domestically and internationally, including the Kozlov friction pendulum, the BAM friction meter, and the ABL friction meter. The Kozlov friction pendulum consists of a main body, a hydraulic press, and a pendulum. During testing, the sample is placed between two top columns. The hydraulic press uses a push rod to eject the top column from its sleeve and presses it firmly. Then, a pendulum of a certain mass falls from a certain starting angle, striking a horizontal striking rod. The striking rod pushes the top column, causing friction on the sample, and whether the sample ignites or explodes is observed. GJB 770B-2005 Method 602.1 (GJB 772A-1997 Method 602.1) is based on the Kozlov friction pendulum method and is suitable for testing the friction sensitivity of solid and slurry explosives. The BAM friction meter used in Europe consists of a base and a friction device. The friction device includes a fixed ceramic rod and a movable ceramic plate. The sample is placed on the ceramic plate, which reciprocates forward and backward under the ceramic rod. The loading device has a weight arm with six slots for hanging weights. Hanging different weights in different slots creates different loads on the ceramic rod, allowing observation of whether the sample ignites or explodes. The ABL friction tester used in the United States consists of a platform, a hydraulic press, fixed wheels, and a pendulum. The sample is evenly spread on the platform according to a certain area. The fixed wheels are lowered to contact the sample, and a certain pressure is applied to the sample through the hydraulic press. Then, the pendulum falls to strike the platform, causing the platform to slide, and observation of whether the sample ignites or explodes is made.

[0004] The aforementioned friction sensitivity testing device and method reflect, to some extent, the ease with which explosives burn and explode under friction. However, they cannot quantitatively characterize the minimum energy required for explosives to burn or explode under friction. Currently, no instrument or method has been established for testing the friction energy of explosives, making it impossible to obtain the minimum combustion and explosion conditions for solid propellants and materials under friction. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a friction energy tester and method, solving the problems of the lack of existing friction energy testing devices and methods for solid propellants and process materials, and the inability to quantitatively characterize them. The present invention can realize the friction energy testing of explosives in the field of propellants such as energetic materials, slurries, and tablets.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A friction energy tester includes a friction device, a worktable, a hot air blower, a hot air box, a camera, and a gas measurement sensor;

[0008] The friction device is mounted on a base on the top surface of the workbench and includes a frame, an eccentric cam linkage mechanism, a servo motor, a bracket, a ceramic plate, a connecting frame, a counterweight, a weight arm, a weight, and a ceramic rod. The eccentric cam linkage mechanism is mounted on the frame, and the servo motor drives it. The bracket is connected to the eccentric cam linkage mechanism, and a ceramic plate is placed on the bracket. A sample can be placed on the ceramic plate, and a transparent hot air box is provided around the ceramic plate. The servo motor drives the eccentric cam linkage mechanism to move the bracket and ceramic plate back and forth. The connecting frame is connected to the top of the frame via a rotating shaft, and the connection point is the rotation point. The counterweight and weight arm are located at both ends of the connecting frame and on the left and right sides of the rotation point. The weight can be placed on the weight arm. The ceramic rod is vertically mounted on the connecting frame and located between the rotation point and the weight. The lower end of the ceramic rod can press against the top surface of the ceramic plate, and the weight can apply pressure to the ceramic rod, causing it to reciprocate and rub against the sample on the ceramic plate.

[0009] The hot air blower is located on the lower layer of the workbench, and is connected to the air inlet pipe and the hot air pipe. The hot air pipe extends upward to the hot air box to control the test temperature of the sample. The gas measurement sensor is located at the air outlet of the hot air box. The camera can capture images of the working area of ​​the ceramic rod and ceramic plate to observe the state of the test sample. The test endpoint is determined by the camera observation and the gas measurement sensor. After the test, the frictional energy of the sample is calculated according to the frictional energy conversion formula.

[0010] The present invention also includes the following technical features:

[0011] Specifically, the base is made of cast steel.

[0012] Specifically, the ceramic plate and ceramic rod are both made of industrial white porcelain.

[0013] Specifically, the surface roughness of the ceramic plate is 9μm-32μm.

[0014] Specifically, the ceramic plate moves 10mm.

[0015] Specifically, the bracket operates at a frequency of 10-300 times per minute, which is remotely adjustable; the bracket moves on two guide rails.

[0016] Specifically, the weight arm has multiple slots for hanging weights; the weights are multiple standard weights of different masses, which are hung in the slots of the weight arm by a ring and a hook. Different weights are hung in different slots, and the load formed on the ceramic rod is 5 to 360 N.

[0017] Specifically, the hot air box is made of 10mm thick plexiglass; hot air is introduced into the bottom of the hot air box for heating, and an air outlet with a diameter of 20mm is provided on the upper right side.

[0018] Specifically, the hot air blower has an outlet temperature of room temperature to 90°C, a temperature control accuracy of ±2°C, and an outlet pressure of 300 Pa.

[0019] The working method of the friction energy tester includes: powering on the system; performing a no-load test run; installing the material to be tested and turning on the hot air blower; loading standard weights onto the weight arm; remotely setting the operating frequency and inputting the loading force; starting the servo motor and beginning the test; the computer collects the operating frequency and NO concentration in real time; when the NO concentration reaches the set value, the computer records the current real-time value; and the computer performs data analysis.

[0020] The formula for calculating frictional energy is: Q = U × N × S, where U is the coefficient of friction, N is the normal force applied to the weight arm, and S is the relative displacement.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] (1) This invention can quantitatively characterize the minimum energy required for a propellant to burn or explode under friction.

[0023] (2) Based on the safety considerations of the solid propellant and process material friction energy testing process, the present invention adopts a human-machine isolated remote operation mode.

[0024] (3) The friction energy testing device adopts an integrated design, with a simple structure, single process action, and high overall reliability.

[0025] (4) The endpoint determination of the friction energy test adopts a combination of camera observation and gas measurement sensor to determine whether the sample is burning or exploding, and the endpoint determination is highly accurate. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a friction energy tester.

[0027] Figure 2 This is a side view of the friction energy tester.

[0028] Figure 3 This is a schematic diagram of the friction device and the weight arm.

[0029] The meanings of the labels in the diagram are as follows:

[0030] 1. Hot air blower, 2. Air inlet pipe, 3. Workbench, 4. Base, 5. Eccentric cam linkage mechanism, 6. Frame, 7. Counterweight, 8. Connecting frame, 9. Ceramic rod, 10. Weight arm, 11. Weight, 12. Servo motor, 13. Hot air pipe, 14. Rotating shaft, 15. Bracket, 16. Ceramic plate. Detailed Implementation

[0031] This invention provides a friction energy tester and method, conceived from the following aspects: First, the friction energy tester of this invention adopts a human-machine isolated remote operation mode. Only a standard weight needs to be manually loaded onto the weight arm before testing. The reciprocating motion of the ceramic plate is driven by an explosion-proof servo motor. No one is present during the testing process, resulting in low safety risk. Second, the friction energy tester is designed based on the "GBT 21567-2008 Test Method for Impact Sensitivity of Dangerous Explosives" and the principle of the BAM friction sensitivity meter, according to specific requirements. The servo motor drives the ceramic plate to reciprocate, while a certain normal pressure is applied to the ceramic rod, causing it to reciprocate and rub against the sample. This allows for the identification of the sample's response to friction, obtaining the minimum energy required for a reaction or change, and thus determining the lowest possible combustion / explosion conditions. Third, the endpoint determination of the friction energy tester combines camera observation with a gas measurement sensor to jointly determine whether the sample is burning or exploding, improving the accuracy of endpoint determination.

[0032] 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, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention. The friction energy tester of the present invention is operated remotely with human-machine isolation. The reciprocating motion of the ceramic plate is driven by a servo motor, and the endpoint is determined by a camera observation and a gas measurement sensor. The testing process is unmanned on-site.

[0033] Example 1:

[0034] like Figures 1 to 3 As shown, this embodiment provides a friction energy tester and method. The friction energy tester includes a friction device, a worktable 3, a hot air blower 1, a hot air box, a camera, a gas measurement sensor, and a computer.

[0035] The friction device is located on the base 4 on the top surface of the workbench 3. The base 4 is made of cast steel and has dimensions of 410mm×200mm×50mm.

[0036] The friction device includes a frame 6, an eccentric cam linkage mechanism 5, a servo motor 12, a bracket 15, a ceramic plate 16, a connecting frame 8, a counterweight 7, a weight arm 10, a weight 11, and a ceramic rod 9. The eccentric cam linkage mechanism 5 is mounted on the frame 6. The servo motor 12 drives the eccentric cam linkage mechanism 5. The eccentric cam linkage mechanism 5 is connected to the bracket 15. The ceramic plate 16 is placed on the bracket 15, and the sample can be placed on the ceramic plate 16. A transparent hot air box is provided around the ceramic plate 16. The servo motor 12 can drive the eccentric cam linkage mechanism 9. Mechanism 5 drives the bracket 15 and ceramic plate 16 to move back and forth; the connecting frame 8 is connected to the top of the frame 6 through the rotating shaft 14, and the connection point is the rotation point. The counterweight 7 and the weight arm 10 are located at both ends of the connecting frame 8 and on the left and right sides of the rotation point. The weight 11 can be placed on the weight arm 10. The ceramic rod 9 is vertically installed on the connecting frame 8 and located between the rotation point and the weight 11. The lower end of the ceramic rod 9 can press on the top surface of the ceramic plate 16. The weight 11 can apply pressure to the ceramic rod 9, so that it reciprocates and rubs the sample on the ceramic plate 16.

[0037] A hot air blower 1 is located on the lower layer of the workbench 3. The hot air blower 1 is connected to an air inlet pipe 2 and a hot air pipe 13, which extends upwards to the hot air chamber for controlling the test temperature of the sample. A gas measurement sensor is located at the air outlet of the hot air chamber. A camera can capture images of the working area of ​​the ceramic rod 9 and ceramic plate 16 to observe the state of the test sample. The test endpoint is determined by the camera observation and the gas measurement sensor. After the test, the frictional energy of the sample is calculated according to the frictional energy conversion formula. The computer of this invention is used for integrated processing of test data.

[0038] Both the ceramic plate 16 and the ceramic rod 9 are made of industrial white porcelain. The ceramic plate 16 has a size of 25mm×25mm×5mm and a surface roughness of 9μm-32μm. The moving distance (amplitude) of the ceramic plate 16 is 10mm. The ceramic rod 9 has a diameter of 10mm and a length of 15mm. The contact center between the ceramic rod 9 and the ceramic plate 16 is the friction point.

[0039] The operating frequency of bracket 15 is measured in real time, and the position switch measures the number of reciprocating cycles of the tray. The operating frequency is remotely adjustable from 10 to 300 times / minute. Bracket 15 moves on two guide rails.

[0040] The servo motor 12 and the eccentric cam linkage mechanism 5 are equipped with a position feedback encoder, providing high control accuracy and remote control and speed adjustment functions.

[0041] The weight arm 10 on the right side of the connecting frame 8 is 700mm long, and the horizontal distance from the rotation point to the friction point is 29mm. The counterweight block 7 is installed on the left end of the connecting frame 8 to balance the torque on both sides. When no weight 11 is added, the torque at the friction point is zero.

[0042] The weight arm 10 has 6 slots, and the horizontal distances between the slots and the friction points of the ceramic rod 9 and the ceramic plate 16 are 110mm, 160mm, 210mm, 260mm, 310mm and 360mm, respectively.

[0043] The weights 11 consist of nine standard weights of different masses, which are hung in the slots of the weight arm 10 using a ring and hook. By hanging different weights 11 in different slots, the load that can be formed on the ceramic rod 9 is: 5-10-20-40-60-80-120-160-240-360 Newtons.

[0044] The ceramic plate 16 is installed inside the hot air box, which is made of 10mm thick plexiglass for easy observation by the camera. Hot air is introduced into the bottom of the hot air box for heating, and an air outlet is provided on the upper right side. The air outlet has a diameter of 20mm, and a gas measuring sensor is installed at the air outlet to measure changes in gas concentration and determine whether the tablet is burning or exploding.

[0045] Hot air blower 1 is selected from equipment that meets industry standards. The outlet temperature of hot air blower 1 is room temperature to 90℃, the temperature control accuracy is ±2℃, and the outlet pressure is 300pa.

[0046] The nitric oxide gas detection sensor is an imported programmable concentration sensor with a range of 0-300 mpp.

[0047] Workbench 3, camera and computer are all selected from equipment that meets industry standards, and the materials used for contact testing of other components are all made of copper, 304 stainless steel or compatible polymer materials.

[0048] Based on the above workflow, the testing method for this device is as follows:

[0049] (1) Power on the system;

[0050] (2) No-load test run;

[0051] (3) Install the material to be tested and turn on the hot air blower;

[0052] (4) Load standard weights onto the weight arm;

[0053] (5) Remotely set the operating frequency and input the loading force;

[0054] (6) Start the servo motor and begin the test;

[0055] (7) The computer collects the operating frequency and NO concentration in real time;

[0056] (8) When the NO concentration reaches the set value, the computer records the current real-time value;

[0057] (9) Computer data analysis.

[0058] The method for calculating frictional energy is as follows: Calculate the frictional energy of the sample according to the frictional energy conversion formula Q=U×N×S;

[0059] Wherein, U: coefficient of friction, taken as 3.0 according to national standard data; N: normal force applied to the weight arm, weight value; S: relative displacement, calculated based on operating frequency.

[0060] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0061] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0062] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A frictional energy tester characterized by, The friction device, the workbench (3), the hot air blower (1), the hot air box, the camera and the gas measuring sensor are included. The friction device is arranged on the base (4) of the top surface of the workbench (3) and includes a rack (6), an eccentric cam connecting rod mechanism (5), a servo motor (12), a bracket (15), a porcelain plate (16), a connecting rack (8), a counterweight block (7), a weight arm (10), a weight (11) and a porcelain rod (9). The eccentric cam connecting rod mechanism (5) is installed on the rack (6), the servo motor (12) is used to drive the eccentric cam connecting rod mechanism (5), the eccentric cam connecting rod mechanism (5) is connected to the bracket (15), the porcelain plate (16) is arranged on the bracket (15), the sample can be placed on the porcelain plate (16), the transparent hot air box is arranged on the periphery of the porcelain plate (16), and the servo motor (12) can drive the eccentric cam connecting rod mechanism (5) to drive the bracket (15) and the porcelain plate (16) to move back and forth left and right. The connecting rack (8) is connected to the top of the rack (6) through a rotating shaft (14), the connecting position is a rotating point, the counterweight block (7) and the weight arm (10) are arranged at two ends of the connecting rack (8) and located on the left and right sides of the rotating point, the weight (11) can be arranged on the weight arm (10), the porcelain rod (9) is vertically installed on the connecting rack (8) and located between the rotating point and the weight (11), the lower end of the porcelain rod (9) can be pressed on the top surface of the porcelain plate (16), and the weight (11) can apply pressure to the porcelain rod (9) to reciprocally rub the sample on the porcelain plate (16). The hot air blower (1) is arranged on the lower layer of the workbench (3), the hot air blower (1) is connected to the air inlet pipe (2) and the hot air pipe (13), the hot air pipe (13) extends upwards and is communicated to the hot air box, and the hot air pipe (13) is used to control the test temperature of the sample. The gas measuring sensor is arranged at the air outlet of the hot air box. The camera can shoot the working area of the porcelain rod (9) and the porcelain plate (16) and is used to observe the state of the test sample. The test end point is determined by the camera observation and the gas measuring sensor, and the friction energy of the sample is calculated according to the friction energy conversion formula after the test is completed.

2. The friction energy tester of claim 1, wherein, The base (4) is made of cast steel.

3. The friction energy tester of claim 1, wherein, The porcelain plate (16) and the porcelain rod (9) are both made of industrial white porcelain.

4. The frictional energy tester of claim 1, wherein, The surface roughness of the porcelain plate (16) is 9 μm-32 μm.

5. The friction energy tester of claim 1 wherein, The moving distance of the porcelain plate (16) is 10 mm.

6. The friction energy tester of claim 1, wherein, The operation frequency of the bracket (15) is 10-300 times / minute, and the bracket (15) is remotely adjustable. The bracket (15) moves on two guide rails.

7. The friction energy tester of claim 1 wherein, The weight arm (10) is provided with a plurality of notches for hanging the weights (11). The weights (11) are a plurality of standard weights (11) with different masses. The standard weights (11) are hung in the notches of the weight arm (10) through a ring and a hook. Different weights (11) are hung in different notches, and the load formed on the porcelain rod (9) is 5-360 N.

8. The friction energy tester of claim 1 wherein, The hot air box is made of a 10 mm thick organic glass plate. The bottom of the hot air box is heated by hot air, the upper right side is provided with an air outlet, and the diameter of the air outlet is 20 mm.

9. The friction energy tester of claim 1 wherein, The outlet temperature of the hot air blower (1) is normal temperature-90 DEG C, the temperature control accuracy is ±2 DEG C, and the outlet pressure is 300 pa.

10. A method of operating a friction energy tester as claimed in any one of claims 1 to 9, characterised in that, The device comprises a friction device, a workbench (3), a hot air blower (1), a hot air box, a camera and a gas measuring sensor. System power on; empty car test run; installation of the measured material, start the air heater; Load the standard weight on the weight arm; Remote set running frequency, input load force; Start servo motor, start testing; computer real-time acquisition of running frequency, NO concentration; when the NO concentration reaches the set value, the computer records the current real-time value; computer data analysis; The formula for calculating the friction energy is Q = U x N x S, where U is the friction coefficient, N is the normal pressure loaded on the weight arm, and S is the relative displacement.

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