CN110715585A - An output pressure test system for electric squibs with variable volume - Google Patents

Abstract

In order to solve the problems of the existing electric detonator output pressure test solution that the volume is fixed, resulting in large estimation error, high cost, difficulty in meeting high-pressure and high-temperature technical requirements, and unfavorable test operation, the present invention provides a variable-volume electric explosion Tube output pressure test system. The test cavity of the present invention adopts a straight channel structure, and relies on the cavity formed by the outlet of the electric squib to be tested and the end face of the loading end of the Hopkinson pressure rod, and the hollow is realized by the axial movement of the Hopkinson pressure rod in the test cavity. The volume of the cavity is arbitrarily variable, and it is suitable for testing the output pressure characteristics of the electric squib in small-volume cavities of different volumes, with good versatility and low cost. After the electric detonator to be tested is installed in the electric detonator installation screw hole of the test chamber of the present invention, the cavity volume between the electric detonator to be tested and the loading end of the Hopkinson pressure rod is the real explosion of the electric detonator. Therefore, the working margin of the electric explosion valve to be tested can be accurately calculated.

Description

An output pressure test system for electric squibs with variable volume

technical field

The invention relates to a variable volume electric detonator output pressure test system, which is used for testing the pressure output characteristics of standard electric detonators in different small-volume cavities, and can be extended to other pyrotechnic products, such as detonators, etc. It can be used to test the explosive pressure performance of explosives.

Background technique

The electric explosion valve uses the high-pressure gas generated by the explosion of the explosive in the electric explosion tube to drive the piston movement, thereby quickly opening and closing the flow path, and is often used in aerospace propulsion systems. The output pressure of the electric explosion tube directly determines the working margin and reliability of the electric explosion valve, so it is the key parameter for the design and research of the electric explosion valve. In order to obtain the output characteristics of the electric detonator, a closed detonator test scheme is usually used, and the output characteristics of the electric detonator are characterized by the pressure curve tested by the pressure sensor.

The existing electric squib output pressure test scheme has the following problems:

1) The standard airtight detonator used is 27ml and 50ml, which is much larger than the real explosion chamber volume of the electric explosion valve. The real cavity explosion pressure estimated by the ideal gas isothermal process has a large error, which is not conducive to the accurate calculation of the electric explosion valve. working margin.

2) In order to obtain the output pressure of the electric detonator in the real cavity, it is necessary to design airtight detonators of different volumes according to the specific product. The test plan is not universal and the cost is high.

3) The real volume of the product is very small, the output pressure of the electric explosion tube is high (>100MPa), the gas temperature is high (>2000K), and a large number of high-temperature metal debris and metal oxide particles fly out, which is extremely destructive. It is difficult for the sensor to meet all the above technical requirements.

4) The current Hopkinson pressure bar pressure measurement scheme adopts an integrated support sleeve structure, which can realize high-voltage and high-frequency testing. The machining process makes high demands and is not conducive to testing operations.

SUMMARY OF THE INVENTION

In order to solve the problems of the existing electric detonator output pressure test solution that the volume is fixed, resulting in large estimation error, high cost, difficulty in meeting high-pressure and high-temperature technical requirements, and unfavorable test operation, the present invention provides a variable-volume electric explosion Tube output pressure test system.

The technical scheme of the present invention is:

A variable volume electric squib output pressure test system, comprising a test cavity, a Hopkinson pressure rod type reflection pressure sensor assembly, an adjustable support assembly, a support ring sleeve assembly, a buffer, a strain tester and an oscilloscope;

Its special features are:

The test chamber is a straight-channel test chamber, which is a cylinder with two ends open, and one end of which is an electric detonator installation threaded hole for installing the electric detonator to be tested;

The Hopkinson pressure rod type reflective pressure sensor assembly includes a Hopkinson pressure rod, a metal protective gasket, a dynamic strain gauge, a head guide sleeve, a tail guide sleeve and an O-shaped rubber sealing ring;

The metal protective gasket is arranged on the loading end of the Hopkinson pressure rod;

The dynamic strain gauge is set in the middle of the Hopkinson compression bar;

The head guide sleeve is a hollow cylindrical structure with two ends open, and the outer side wall of one end is provided with a shoulder; the inner side wall of the head guide sleeve is provided with a sealing ring surface for installing the O-shaped rubber sealing ring, and the sealing The ring surface is evenly coated with grease;

The tail guide sleeve is a cylindrical structure with openings at both ends, the inner wall is provided with a sealing ring surface for installing the O-shaped rubber sealing ring, and the sealing ring surface is evenly coated with grease;

The head guide sleeve and the tail guide sleeve are both sleeved outside the Hopkinson pressure rod, and together form the support structure of the Hopkinson pressure rod; the head guide sleeve is close to the loading end of the Hopkinson pressure rod, and the two are clearance fit , the gap on one side is 10-20 microns; the tail guide sleeve is close to the unloading end of the Hopkinson pressure rod, and the two are clearance fit;

The adjustable support base includes a first adjustable support base, a second adjustable support base and a third adjustable support base;

The support ring sleeve assembly includes a first support ring sleeve and a second support ring sleeve;

The straight channel test chamber is set on the first adjustable support base 1, the first support ring sleeve is set on the second adjustable support base, and the second support ring sleeve is set on the third adjustable support base;

One end of the head guide sleeve is set in the straight channel test cavity, the other end is set in the first support ring sleeve, and its axial position is defined by the shoulder; the outer wall of the head guide sleeve is connected to the straight channel test cavity One-sided 20-50 micron clearance fit between the inner walls;

The tail guide sleeve is arranged in the second support ring sleeve;

The straight channel test chamber, the Hopkinson pressure rod, the head guide sleeve, the first support ring sleeve and the second support ring sleeve are coaxially arranged, and the Hopkinson pressure rod can be pivoted in the head guide sleeve and the tail guide sleeve Forward movement; tail guide sleeve and Hopkinson strut limited by buffer.

Further, the metal protection gasket is a circular metal sheet with a thickness of 0.5 mm and a diameter equal to the diameter of the Hopkinson pressure rod.

Further, the metal protection gasket is pasted on the loading end of the Hopkinson pressure rod through epoxy resin.

Further, the grease is 3# lithium molybdenum disulfide grease.

Further, the length of the head guide sleeve and the tail guide sleeve is 50-100 mm.

The beneficial effects of the present invention compared with the prior art are:

1. The test chamber of the present invention adopts a straight channel structure, relying on the cavity formed by the outlet of the electric squib to be tested and the end face of the loading end of the Hopkinson pressure rod, through the axial movement of the Hopkinson pressure rod in the test chamber to realize the test. The volume of the cavity is arbitrarily variable, and it can be applied to the test of the output pressure characteristics of the electric squib in small-volume cavities of different volumes, with good versatility and low cost.

2. After the electric detonator to be tested is installed in the electric detonator installation screw hole of the test chamber of the present invention, the cavity volume between the electric detonator to be tested and the loading end of the Hopkinson pressure rod is the volume of the electric detonator. Therefore, the working margin of the electric explosion valve to be tested can be accurately calculated.

3. The present invention adopts the Hopkinson pressure rod type reflective pressure sensor assembly to realize the high pressure and high frequency test of the small cavity, and sets the metal protection gasket at the end of the loading end of the Hopkinson pressure rod to avoid the Hopkinson pressure rod from being damaged by metal fragments. The impact damage and ablation of the chips make the Hopkinson pressure bar reusable in high temperature and high pressure test environments.

4. The head guide sleeve in the present invention is provided with a shoulder, which can limit the axial position of the head guide sleeve, and can also accurately measure the explosion cavity volume of the electric explosion valve to be tested.

5. The support structure of the Hopkinson pressure rod in the present invention adopts a segmented design in the form of "head guide sleeve + tail guide sleeve", which avoids processing an integrated support sleeve that is the same length as the Hopkinson pressure rod. and easier to use.

Description of drawings

FIG. 1 is a schematic structural diagram of an output pressure test system for an electric squib of the present invention (strain tester and oscilloscope are not shown).

FIG. 2 is a schematic structural diagram of the Hopkinson pressure rod type reflective pressure sensor assembly in the present invention.

FIG. 3 is a schematic diagram of a straight-channel test chamber and a variable volume in the present invention.

Description of reference numbers:

1- The first adjustable support seat, 2- Straight channel test chamber, 3- Metal protection gasket, 4- Head guide sleeve, 5- O-ring rubber seal, 6- Dynamic strain gauge, 7- Hopkinson Pressure rod, 8-first support ring sleeve, 9-tail guide sleeve, 10-buffer, 11-shoulder, 12-electric squib mounting threaded hole, 13-second adjustable support seat, 14-third adjustable Adjust the support base, 15- the second support ring sleeve, 16- the cavity.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

As shown in FIG. 1 , the variable volume electric squib output pressure test system provided by this embodiment includes a straight channel test chamber 2, a Hopkinson pressure rod type reflective pressure sensor assembly, a first support ring sleeve 8, The second support ring sleeve 15 , the first adjustable support base 1 , the second adjustable support base 13 , the third adjustable support base 14 , the buffer 10 , the strain tester and the oscilloscope.

As shown in Figure 2, the Hopkinson pressure rod type reflective pressure sensor assembly includes a Hopkinson pressure rod 7, a metal protective gasket 3, a dynamic strain gauge 6, a head guide sleeve 4, a tail guide sleeve 9 and an O-ring rubber seal Circle 5.

The metal protective gasket 3 is pasted on the loading end of the Hopkinson pressure rod 7 through epoxy resin; the metal protective gasket 3 can protect the Hopkinson pressure rod 7 and avoid the impact damage of the Hopkinson pressure rod 7 by metal debris and Ablation, to achieve high temperature and metal debris impact environmental test, so that the Hopkinson pressure bar 7 can be reused; the metal protective gasket 3 is a consumable substitute and can be replaced; the metal protective gasket 3 preferably has a uniform thickness of 0.5mm , a metal sheet with the same diameter as the Hopkinson pressure rod 7 .

The dynamic strain gauge 6 is arranged on the Hopkinson pressure bar 7 at a position about 150 mm away from the loading end, and is used to feel the dynamic strain generated by the Hopkinson pressure bar 7 . The dynamic strain gauge 6 is connected to the input end of the strain tester, and the electrical signal of the dynamic strain gauge 6 is collected and amplified by the strain tester, and then displayed by the oscilloscope.

The head guide sleeve 4 is a hollow cylindrical structure with openings at both ends, and a shoulder 11 is provided on the outer side wall of one end; the inner side walls of both ends of the head guide sleeve 4 are provided with O-shaped rubber sealing rings 5 for installing The sealing ring surface is evenly coated with 3# molybdenum disulfide lithium base grease;

The head guide sleeve 4 is one of the key structures of the present invention, and is used to realize three functions:

①The outer wall of the head guide sleeve 4 and the inner wall of the straight channel test chamber 2 are fitted with a gap of 20-50 microns, which can play a gap sealing function at the moment of explosion, and can release the gas pressure after the test is completed;

② The inner wall of the head guide sleeve 4 is matched with the outer wall of the Hopkinson pressure rod 7, and is sealed with an O-shaped rubber sealing ring 5 to prevent gas from entering the gap between the head guide sleeve 4 and the Hopkinson pressure rod 7, preventing Vibration affects the circumferential free state of Hopkinson strut 7;

③The shoulder 11 on the head guide sleeve 4 is used to limit the axial position of the head guide sleeve 4. In addition, the distance between the end face of the test chamber 2 of the straight channel and the shoulder 11 can accurately obtain the electric explosion valve to be tested and the distance between them. The volume of the sealed cavity between the Hopkinson pressure rods 7.

The tail guide sleeve 9 is a hollow cylindrical structure with openings at both ends, and a sealing ring surface for installing the O-shaped rubber sealing ring 5 is arranged on its inner side wall, and the sealing ring surface is evenly coated with 3# molybdenum disulfide lithium base grease ; The tail guide sleeve 9 and the Hopkinson pressure rod 7 adopt clearance fit, and use the O-shaped rubber sealing ring 5 to achieve sound insulation, so as to ensure the circumferential free state of the Hopkinson pressure rod 7.

The head guide sleeve 4 and the tail guide sleeve 9 are both sleeved outside the Hopkinson pressure bar 7, which together constitute the support structure of the Hopkinson pressure bar 7. This segmented design avoids processing and Hopkinson pressure bars. 7. One-piece support sleeves of equal length; if the Hopkinson pressure bar 7 is longer, one or more tail guide sleeves 9 can be added to the middle of the Hopkinson pressure bar 7 .

When assembling, install the head guide sleeve 4 from the loading end of the Hopkinson pressure bar 7, and install the tail guide sleeve 9 from the unloading end of the Hopkinson pressure bar 7 to avoid passing through the position of the dynamic strain gauge 6. .

Because the axial length of the head guide sleeve 4 and the tail guide sleeve 9 is about 50-100mm, which is much shorter than the length of the Hopkinson pressure bar 7 (on the order of 1000mm), instead of the traditional Hopkinson pressure bar 7 having the same length The structure of the support sleeve prevents the lead wire of the dynamic strain gauge 6 from passing between the Hopkinson pressure rod 7 and the support sleeve, which is convenient for assembly and use.

As shown in Figure 3, the straight channel test chamber 2 is a thick-walled cylindrical structure with both ends open. The wall thickness and material of the cylinder are determined according to the output pressure of the electric squib to be tested; one end of the straight channel test chamber 2 The threaded hole 12 is used to install the electric detonator to be tested, and the other end is used to place the Hopkinson pressure rod type reflection pressure sensor assembly;

The straight channel test chamber 2 itself is open, and a volume-adjustable cavity 16 is located between the outlet of the electric squib to be tested and the end face of the metal protection gasket 3. When the Hopkinson pressure rod 7 moves axially, The volume of the cavity 16 between the outlet of the electric squib to be tested and the end face of the metal protection gasket 3 will change. The volume of the cavity is equal to the distance from the outlet of the electric squib to be tested to the end face of the metal protection gasket 3 multiplied by the inner circle area of the cross-section of the straight-channel test chamber 2. Since the cross-section of the straight-channel test chamber 2 is completed once it is manufactured The inner circle area of is a fixed value. Therefore, the volume of the cavity is determined by the distance from the outlet of the electric squib to be measured to the end face of the metal protective gasket 3. The distance can be indirectly measured in the following two ways:

① Before installing the electric detonator to be tested, observe the position and state of the end face of the metal protection gasket 3 from the installation threaded hole 12 of the electric detonator, and use a depth gauge to measure the distance between the outer end face of the straight channel test chamber 2 and the end face of the metal protection gasket 3 The distance is denoted as ΔH, and the distance ΔH minus the depth of the threaded hole 12 for the installation of the electric squib is the distance from the outlet of the electric squib to be measured to the end face of the metal protection gasket 3 .

②Use a vernier caliper to measure the distance from the shoulder 11 of the head guide sleeve 4 to the outlet end face of the straight channel test chamber 2, marked as ΔL, and use the actual axial size of the head guide sleeve 4 and the actual axis of the straight channel test chamber 2 Calculate the distance from the outlet of the electric squib to be measured to the end face of the metal protection gasket 3 according to the dimension.

As shown in FIG. 3 , in the present invention, the straight channel test chamber 2 is provided on the first adjustable support base 1 , the first support ring sleeve 8 is provided on the second adjustable support base 13 , and the second support ring sleeve 15 is provided on the third adjustable support base 14;

The Hopkinson pressure rod type reflective pressure sensor assembly is supported by the first support ring sleeve 8 and the second support ring sleeve 15, one end of the head guide sleeve 4 in the Hopkinson pressure rod type reflective pressure sensor assembly and the Hopkinson pressure rod The loading end of 7 is located in the test chamber 2 of the straight channel, at the position to be tested;

In addition, the straight channel test chamber 2, the Hopkinson pressure rod type reflective pressure sensor assembly, the first support ring sleeve 8 and the second support ring sleeve 15 are coaxially arranged, and the Hopkinson pressure rod 7 is located between the head guide sleeve 4 and the head guide sleeve 4. The tail guide sleeve 9 can move axially, the head guide sleeve 4 is limited by the first support ring sleeve 8 , and the tail guide sleeve 9 and the Hopkinson pressure rod 7 are limited by the buffer 10 .

The working principle of the present invention:

The present invention utilizes the straight channel test cavity 2 to cooperate with the Hopkinson pressure rod type reflective pressure sensor to realize the variable volume function, and utilizes the Hopkinson pressure rod type reflective pressure sensor assembly to realize the high pressure and high output pressure of the electric squib to be measured. frequency test.

Claims (5)

1. A volume-variable output pressure test system for an electric detonator comprises a test cavity, a Hopkinson pressure bar type reflection pressure sensor assembly, an adjustable support seat assembly, a support ring sleeve assembly, a buffer, a strain tester and an oscilloscope, wherein the test cavity is provided with a pressure sensor;

the method is characterized in that:

the test cavity is a straight channel test cavity (2) and is a cylinder with two open ends, and one end of the test cavity is provided with an electric detonator mounting threaded hole (12) for mounting an electric detonator to be tested;

the Hopkinson pressure bar type reflection pressure sensor assembly comprises a Hopkinson pressure bar (7), a metal protection gasket (3), a dynamic strain gauge (6), a head guide sleeve (4), a tail guide sleeve (9) and an O-shaped rubber sealing ring (5);

the metal protection gasket (3) is arranged at the loading end of the Hopkinson pressure bar (7);

the dynamic strain gauge (6) is arranged in the middle of the Hopkinson pressure bar (7);

the head guide sleeve (4) is of a hollow cylindrical structure with two open ends, and the outer side wall of one end of the head guide sleeve is provided with a convex shoulder (11); a sealing ring surface for mounting the O-shaped rubber sealing ring (5) is arranged on the inner side wall of the head guide sleeve (4), and lubricating grease is uniformly coated on the sealing ring surface;

the tail guide sleeve (9) is of a cylindrical structure with openings at two ends, the inner wall of the tail guide sleeve is provided with a sealing ring surface for mounting the O-shaped rubber sealing ring (5), and lubricating grease is uniformly coated on the sealing ring surface;

the head guide sleeve (4) and the tail guide sleeve (9) are sleeved outside the Hopkinson pressure bar (7) to form a supporting structure of the Hopkinson pressure bar (7) together; the head guide sleeve (4) is close to a loading end of the Hopkinson pressure bar (7), the head guide sleeve and the Hopkinson pressure bar are in clearance fit, and the clearance on one side is 10-20 micrometers; the tail guide sleeve (9) is close to the unloading end of the Hopkinson pressure bar (7), and the two are in clearance fit;

the adjustable support assembly comprises a first adjustable support seat (1), a second adjustable support seat (13) and a third adjustable support seat (14);

the support ring sleeve assembly comprises a first support ring sleeve (8) and a second support ring sleeve (15);

the straight channel test chamber (2) is arranged on the first adjustable supporting seat (1), the first supporting ring sleeve (8) is arranged on the second adjustable supporting seat (13), and the second supporting ring sleeve (15) is arranged on the third adjustable supporting seat (14);

one end of the head guide sleeve (4) is arranged in the straight channel test cavity (2), the other end of the head guide sleeve is arranged in the first supporting ring sleeve (8), and the axial position of the head guide sleeve is limited by the convex shoulder (11); the outer wall of the head guide sleeve (4) is in clearance fit with the inner wall of the straight channel test cavity (2) by adopting a clearance fit with 20-50 microns on one side;

the tail guide sleeve (9) is arranged in the second supporting ring sleeve (15);

the straight channel test cavity (2), the Hopkinson pressure bar (7), the head guide sleeve (4), the first support ring sleeve (8) and the second support ring sleeve (15) are coaxially arranged, and the Hopkinson pressure bar (7) can axially move in the head guide sleeve (4) and the tail guide sleeve (9); the tail guide sleeve (9) and the Hopkinson pressure bar (7) are limited by the buffer (10).

2. An electric detonator output pressure test system of claim 1 wherein: the metal protection gasket (3) is a circular metal sheet with the thickness of 0.5mm and the diameter equal to that of the Hopkinson pressure bar (7).

3. An electric detonator output pressure test system of claim 2 wherein: the metal protection gasket (3) is adhered to the loading end of the Hopkinson pressure bar (7) through epoxy resin.

4. An electric detonator output pressure test system of claim 3 wherein: the lubricating grease is 3# molybdenum disulfide lithium-based lubricating grease.

5. An electric detonator output pressure test system of any one of claims 1 to 4 wherein: the length of the head guide sleeve (4) and the length of the tail guide sleeve (9) are 50-100 mm.

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