RU2328748C2 - Device for determining actuation time of initiatorless primer/ detonator (variants thereof) - Google Patents

Abstract

FIELD: devices for measuring action time of means for initiation.

SUBSTANCE: two proposed variants of a device for determining actuation time of an initiatorless primer/ detonator fitted with an impact wave tube in a transparent envelope used to conduct the pulse from an initiating device. The device according to variant 1 comprises a chronograph, a chronograph start photosensor responding to the radiation of a detonation front which propagates inside the impact wave tube after initiation of the later, a chronograph stop sensor responding to the impact effect upon actuation of the primer/detonator. The device according to variant 2 comprises a photosensor being used as a chronograph stop sensor responding to the radiation upon actuation of the primer/detonator, disposed around the later and placed into a bushing with a not less than 5 mm wide and 3-10 mm long slot cut therein.

EFFECT: invention ensures reliable, safe and precise measurement of the actuation time of initiatorless primers/detonators in a multiple use device.

6 cl, 3 dwg

Description

The invention relates to the field of measuring the response time of means - initiation, namely, initiator-free detonator capsules (KDBI) containing, as a conductor of an initiating pulse, a low-power detonating cord such as a shock wave tube (UVT) with a translucent sheath.

There are various methods for determining the parameters of explosive processes, based on direct measurement of the propagation time of these processes.

There are optical methods for measuring the velocities of explosive processes, in which the formation of the propagation time curve of the process is carried out by moving the film or by scanning the glow of the explosion with a rotating mirror. These methods are implemented using devices called high-speed photo recorders that operate in continuous sweep mode, or devices called time magnifiers, which use non-inertia lamps with constant luminosity or flash lamps with a time-varying light intensity, switched on by pulses from position sensors the front of the investigated process with the recording of signals from the lamps on photo paper mounted on a rotating drum (see AS USSR No. 297924 A, 03/11/1971, G01P 3/00, C06C 5/06).

A significant drawback of drum photo recorders is the low linear sweep speed (up to 200 m / s), the increase of which is limited by technical capabilities: precise drum balancing, the use of vacuum, etc. are required. It is difficult to exceed the speed of 200 m / s, because at higher speeds, the emulsion layer is crushed and the film is destroyed by centrifugal forces. In addition, such devices contain complex and bulky components and assemblies, in particular complex precision optical systems for focusing a light beam on photo paper, a complex relay system that turns off constant-light tubes in a certain sequence to eliminate overlapping light paths during repeated drum revolutions and loss marks on photo paper, complex schemes for firing flash lamps on pulse transformers and battery capacitors. In devices with a rotating mirror, the synchronization unit is used, which is necessary to combine the beginning of the explosion of a charge with a certain position of the mirror relative to the film, which is an electrical circuit operating at a voltage of 3000-5000 V. A drum with photo paper or a mirror is rotated using motors, such as asynchronous engines, and to accurately determine the linear sweep speed, it is necessary to accurately measure the number of revolutions of the drum or mirror. To regulate and stabilize the speed of rotation of the drum and to accurately measure the number of revolutions, it is necessary to use additional special methods and sophisticated equipment. All this limits the use of such devices in laboratory tests and makes them unsuitable for measuring the response time of a CDBI containing an initiating low-power UVT in real production conditions. In addition, such devices do not provide high measurement accuracy (the error in measuring the propagation time of the stationary detonation process is 1%, and the process proceeding with a variable speed of 2.5%) due to the presence of a complex of factors that adversely affect the measurement accuracy. These factors include, in particular, the inertia of the ignition schemes of flash lamps due to the presence of a pulse transformer (or inertia relays that turn off constant-light lamps), the inability to achieve absolute balancing of the drum and the stability of the rotation speed of the drum or mirror, and the error in measuring the speed . Since the detonation front is not a point, the time curve on the photo paper has blurry edges, which significantly affects the accuracy of measuring the trace on the photo paper in conjunction with the error that the devices have with the help of which the trace is measured.

There are chronographic methods for measuring the speeds of explosive processes in which devices for measuring short periods of time (chronographs) are used. Such devices record the time during which the investigated process (detonation, explosion) passes through two or more fixed points. In particular, a device is known that implements a chronographic method for measuring the detonation velocity of explosives (EX) —the Dotrish method, based on the use of mechanical effects (the mechanical energy of an explosive explosion) that accompany detonation. Two pieces of a detonating cord of a certain length with a known detonation velocity are introduced into the charge of the explosive being investigated, initiated from one side, at a certain distance from each other. The detonating cord in this case plays the role of a chronograph. The desired detonation velocity of the explosives is calculated by the formula, which includes the parameters of the detonating cords (US 3528280 A, 09/15/1970, G01N 33/22, US 3572095 A, 03/23/1971, G01N 33/22).

However, such devices cannot be used to measure the response time of a CDBI containing an initiating low-power UVT, since the methods implemented in these devices involve the use of the explosion energy of the test explosive for mechanical destruction (full or partial) of certain structural details of these devices. The propagation time of a detonation wave along a segment of a low-power UVT, which is part of the KDBI, is an integral part of the total response time of the KDBI as a whole. During detonation of low-power shock-wave equipment, the explosion of an explosive occurs exclusively inside the shock-wave device shell; therefore, the destruction by the explosion energy of an object located at any distance from the shock-wave device, up to direct contact, is completely excluded. Another disadvantage of these devices is that their design does not provide reusable use, since the destroyed structural elements require complete replacement for subsequent testing. In addition, such devices are influenced by a number of factors that reduce the accuracy of the measurement, since they are based on a comparison of the measured detonation propagation time with the known and constant detonation propagation time in the detonating cord. In this case, the accuracy depends, first of all, on the uniformity of the detonation of the cord, the accuracy of measuring the distance between the points at which detonating cord segments (base) are introduced into the test volume of the explosive, i.e. the distance at which the propagation time of detonation of the explosive is actually measured, from the accuracy of measuring the distance between the mark of the middle of the detonating cord and the mark of the meeting point of the detonation waves of the cord segments. The propagation time of detonation in a detonating cord is measured with an accuracy of 1.5-2%. The base is measured with an accuracy of 1 mm, it is difficult to determine this distance more precisely, because it is possible to show explosives at the walls of nests. The possible error in measuring the distance between the marks is approximately 2%, and the maximum value of the relative error in determining the propagation time of detonation by this method is ± 4.5%.

A device is also known for determining the propagation time and detonation velocity of explosives, using the electromagnetic effect that accompanies detonation. The test explosive charge is placed inside a hollow cylinder with one open end and is initiated using a detonator. When a detonation wave propagates along an explosive charge along the longitudinal axis of the cylinder, electromagnetic waves are emitted at the frequencies of the megahertz radio range, which is captured by two slots cut in the cylinder wall at a fixed distance from each other in the direction of the longitudinal axis of the cylinder, i.e. along the propagation of the detonation wave. The signals induced on the walls of the slots are fed through the corresponding electrical circuit to the inputs of the oscilloscope, on the screen of which these signals are displayed as pulses of positive polarity, and the distance between the pulses on the oscilloscope screen at a selected sweep scale determines the time the detonation wave travels the distance between the slots in the cylinder (US 3,852,994 A, 12/10/1974, C01L 5/14).

Such a system is unsuitable for measuring the response time of CDBIs containing an initiating low-power UHF, since the explosive charge power in the UHF is such that when the detonation propagates in the UHF, the radiation effect is either absent or the power of this radiation is so small that it cannot be detected using the aforementioned device slot antenna, therefore, it is difficult to measure the propagation time of detonation along the UHT segment as part of the CDBI. Another very significant drawback of this device is that prior to testing it is not known in advance at what frequencies the radiation will take place and, especially, at what frequencies it will have maximum power. Therefore, in the general case, not one, but several pairs of slots should be made in the cylinder wall, each of which should be tuned to its own frequency. The adjustment of the slots is carried out by filling them with a dielectric, which is a certain technological complexity. Moreover, there is no guarantee that during detonation there will be electromagnetic radiation at least at one of the frequencies to which the pairs of slots are tuned, and the power of this radiation will have a level sufficient to be detected by the indicated device. The measurement accuracy in this case is low due to the fact that the propagation time of the detonation wave is determined by measuring the distance between pulses on the screen of the oscilloscope. Those. The speed of the oscilloscope, its resolution, and the beam width on the screen are important. The accuracy of measurements using this device does not allow it to be used to record the response time of a CDBI containing an initiating low-power UVT.

Closest to the proposed invention is a device for determining the detonation speed of low-power detonating cords of the "waveguide" type with a translucent sheath, in which the propagation time of a detonation wave is measured inside a segment of a low-power shock wave with a translucent sheath. The device contains two photosensors located at a fixed distance from each other, a power source and a chronograph, interconnected, means for attaching a waveguide between the photosensors, the initiating device. As photosensors, highly sensitive phototransistors are used, the operating range of which lies in the wavelength range of the visible radiation of the electromagnetic spectrum, and as a chronograph, a digital electronic time meter, the start and stop of which are carried out by signals from photosensors that respond to light radiation from the detonation wave front passing above them inside the waveguide initiated by an initiating device. The detonation velocity is defined as the average speed of the detonation wave propagating the distance between the photo sensors (RU No. 2232388 C2, 07/10/2004, G01N 33/22).

Measurement of the response time of a CDBI using a known device is very difficult, since the design of the sensor stopping the chronograph is not designed to work with detonators with high destructive ability, in contrast to low-power UVT, which does not have any destructive effect on surrounding objects, which can lead to significant error in measuring the response time or the impossibility of fixing it.

An object of the invention is to provide a device for measuring the response time of an initiator-free detonator capsule containing, as a conductor of the initiating pulse, a segment of a low-power detonating cord of the “shock wave tube” type with a translucent sheath.

The technical result of the invention is the provision of an accurate (relative measurement error of ± 2%) and reliable measurement of the response time of initiator-free detonator caps, effective in real production conditions.

The technical result is achieved in two versions of the device for determining the response time of an initiator-free detonator capsule having a shock wave tube with a translucent sheath as a pulse conductor from the initiating device.

Option 1

The device contains a chronograph, a chronograph trigger photosensor that responds to radiation from the detonation wave front passing inside the shock wave tube after its initiation, and a chronograph stop piezo sensor that responds to shock when the detonator capsule is triggered. The chronograph start-up photosensor is located near the shock wave tube at a distance along its length of at least 30 cm from the initiating device and at a distance of 1 m along its length from the end fixed in the detonator capsule. The chronograph stop piezosensor is located on a metal plate, on the opposite side of which a detonator capsule is placed opposite it, and the plate thickness at the sensor mount is 10-30 mm.

As a chronograph triggering photosensor, a sensor with an operating range in the wavelength region covering the visible and infrared parts of the electromagnetic spectrum can be used.

Option 2

The device contains a chronograph, a chronograph trigger photosensor that responds to radiation from the detonation wave front passing inside the shock wave tube after its initiation, a chronograph stop photosensor that responds to radiation when the detonator capsule is triggered. The chronograph start-up photosensor is located near the shock wave tube at a distance along its length of at least 30 cm from the initiating device and at a distance of 1 m along its length from the end fixed in the detonator capsule. The chronograph stop photocell is located near the detonator capsule placed in a metal sleeve, in which a slot is made with a width of at least 5 mm and a length of 3-10 mm.

As a chronograph triggering photosensor, a sensor with an operating range in the wavelength region covering the visible and infrared parts of the electromagnetic spectrum can be used.

As a chronograph stop photodetector, a sensor with an operating range in the wavelength region covering the visible and infrared parts of the electromagnetic spectrum can be used.

The chronograph stop photosensor can be equipped with a protective screen against fragments when the detonator capsule is triggered.

The invention is illustrated by the following drawings.

Figure 1 is a schematic illustration of a device for determining the response time of an initiator-free detonator capsule having a shock wave tube with a translucent sheath as a pulse conductor from the initiating device.

Figure 2 - schematic representation of the placement of the piezoelectric stop chronograph in the device according to option 1.

Figure 3 is a schematic illustration of the placement of the stop chronograph photosensor in the device of embodiment 2.

In figure 1, the positions indicated:

1. detonator capsule

2. shock wave tube

3. the initiating device by which the initiation of the UHT

4. chronograph

5. chronograph start sensor

6. reference point when starting the chronograph

7. chronograph stop sensor

8. sensor power supply

9. anti-interference communication lines

10. explosion proof housing

11. hole for UVT

12. hole for the passage of radiation from the front of the detonation wave

13. test chamber

14. direction of motion of the front of the detonation wave

In figure 2, the positions indicated:

1. detonator capsule

2. shock wave tube

16. piezoelectric stop chronograph

15. metal plate

- толщина металлической пластины в месте крепления пьезодатчика

- the thickness of the metal plate at the mounting point of the piezosensor

In figure 3, the positions indicated:

1. detonator capsule

2. shock wave tube

17. sleeve

18. slot for the passage of radiation arising from the operation of the detonator capsule

19. screen

20. chronograph stop photo sensor

A - one of the possible positions of the stop chronograph photosensor

B - one of the possible positions of the stop chronograph photosensor

a - slot width

C is the length of the gap.

The response time of a detonator capsule having a shock wave tube with a translucent shell as a pulse conductor from the initiating device, in this case, is the sum of the propagation time of the detonation wave along the segment of the initiating UHT in the section from a predetermined point on this segment to the end of the segment fixed in the cylinder liner, and the response time of the detonator itself, defined as the time elapsed from the moment the initiating pulse was supplied from the UHT to the moment of mechanical destruction of the shell of the detonator shell as a result of detonation of the explosive charge inside the detonator. The length of the segment of the initiating UHT and the position on it of the point from which the countdown of the propagation time of the detonation wave along the segment begins are selected so that the distance from this point to the end of the segment fixed in the cylinder liner is 1 m. The distance from this point to the other, free, end of the segment from which its initiation begins should be at least 30 cm, which is necessary for the detonation process to achieve maximum stability after the initiation of an explosive in a shock wave prior to measurement.

The measurement of this time interval is carried out by a chronograph, which is a precision measuring instrument of time intervals and controlled by signals from sensors recording the moments of the beginning and end of the countdown. The start time of the response time is the moment the front of the detonation wave propagates inside the UHT segment after it is initiated by the reference point, and the end time is the moment the detonator shell body is destroyed as a result of the internal explosive charge triggering.

The moment the clock starts is recorded by the first sensor, the signal from which starts the chronograph. The first sensor is a photosensor in which a highly sensitive photodetector is used as a sensitive element, the operating range of which lies in the wavelength region corresponding to the visible or infrared part of the electromagnetic spectrum. The sensor turns on when the front of the detonation wave passes over it and, at the same time, it receives powerful electromagnetic radiation on its sensitive element, which occurs when the detonation wave propagates along the explosive charge inside the UHF.

The moment of the end of the countdown of the CD operation time is recorded by the second sensor, the signal from which stops the chronograph, and the measured time interval is fixed on the indicator of the latter. Since the destruction of the case of the detonator sleeve when the internal explosive charge is triggered is accompanied by a number of physical processes, it is possible to fix the moment of the end of the countdown of the CD operation time in several ways, using various types of sensors as the second sensor, namely:

=10-30 мм. При использовании более тонкой пластины она приходит в негодность после однократного применения либо вносит серьезную погрешность в измерение. Использование более толстой пластины нецелесообразно в виду ухудшения чувствительности датчика и увеличения погрешности измерения.1. A piezoelectric transducer is a vibration transducer that responds to mechanical shock that occurs when a CD is activated and the case of its sleeve is destroyed due to detonation of the internal explosive charge. Moreover, it was experimentally established that the maximum accuracy and reliability of this type of sensor is achieved when it is located on a metal plate, on the opposite side of which a detonator capsule is placed, and the optimal plate thickness at the sensor mounting

= 10-30 mm. When using a thinner plate, it becomes unusable after a single application or introduces a serious error in the measurement. The use of a thicker plate is impractical in view of the deterioration of the sensitivity of the sensor and an increase in the measurement error.

2. A photosensor, the sensitive element of which is a highly sensitive photodetector, the operating range of which lies in the wavelength region corresponding to the visible or infrared part of the electromagnetic spectrum, responding to electromagnetic radiation with the corresponding wavelengths of the electromagnetic spectrum, which occurs when the CD operates and the case of its sleeve is destroyed due to detonation of internal explosive charge. During experimental studies, it was found that the maximum accuracy and reliability of this type of sensor is achieved by placing it near the detonator capsule, placed in a metal sleeve, in which a slot is made with a width of at least 5 mm and a length of 3-10 mm along the detonator capsule . The sleeve protects the sensor from large fragments, and also limits the flow of radiation when the detonator capsule is triggered by a gap of the indicated dimensions. An increase in the geometrical dimensions of the slit (a, c) leads to an increase in the measurement error, and a decrease leads to a decrease in the sensitivity of this method when using known photo sensors. Moreover, the photosensor can be placed with the possibility of its response to radiation that occurs when the detonator capsule is triggered, both opposite the slot and in any spatial position near the detonator capsule placed in the sleeve (see Fig. 3: A, B). To protect against fragments of the detonator capsule, the photosensor may be equipped with a protective screen, for example, in the form of a metal mesh.

The device operates as follows (see figure 1). The initiating device 3 initiates the UHT 2 segment. At the UHT, it passes through the channel 11 in the explosion-proof housing 10 of the photosensor 5. The detonation wave front, propagating along the internal UHT channel in the direction indicated by arrow 14, passes the start point of the response time 6 over the hole 12 of the explosion-proof housing 10 5. The radiation (light or infrared, depending on the type of photodetector of the photosensor) from the front of the detonation wave enters through the hole 12 to the center of the sensitive zone of the photosensitive element receiver 5. The electric circuit of the photosensor converts in a certain way the signal from the photodetector and generates a control signal for starting the chronograph 4, which is transmitted to the triggering input of the chronograph ("START") via the corresponding communication line 9. Chronograph 4 starts the countdown of the response of the CBDI. Further, the detonation wave, passing through the entire segment of the UVT 2, initiates the explosive charge inside the detonator 1, when triggered, the sensor 7, depending on its type and the selected type of influence on it, gives a signal that is converted by the sensor circuit into a control signal to stop the chronograph 4 and transmitted to the stopping input of the chronograph ("STOP") via the corresponding communication line 9. The signal from the sensor 7 stops the chronograph 4, which fixes the value of the response time of the KDBI equal to the time interval from the moment passed the front of the detonation wave in the internal channel of the segment of the shock wave 2 of the reference point 6 until the detonator 1 is activated, recorded by the sensor 7.

By carefully selecting the elements of the electrical circuits of the sensors 5 and 7, as well as the chronograph 4 according to the sensitivity of the inputs, it is possible to ensure that the propagation delay of the signals from the sensors 5 and 7 to the inputs of the chronograph will be the same across both channels, then the measurement errors associated with the inertia of the sensors and Chronograph input circuits will be compensated. In this case, the main measurement error will be the error in determining the position on the UVT segment of the reference point 6, and if we take into account that the length of the initiating UVT segment 2 and the position of the reference point 6 on it can be determined very accurately, then the measured error of the method will be small (± 2%)

Thus, the invention allows, in real production conditions, using the two devices described above, to make accurate and reliable measurements of the response time of an initiator-free detonator capsule having a shock wave tube with a translucent sheath as a pulse conductor from the initiating device.

Claims (6)

1. A device for determining the response time of an initiator-free detonator capsule having a shock wave tube with a translucent sheath as a pulse conductor from the initiating device, comprising a chronograph, a chronograph triggering photosensor that responds to radiation from the detonation wave front passing inside the shock wave tube after it initiation, chronograph stop sensor, characterized in that the chronograph start photo sensor is located near the shock wave tube at a distance along its length not less than it is 30 cm from the initiating device and at a distance of 1 m along its length fixed in the detonator capsule, it contains a piezoelectric transducer that responds to shock when the detonator capsule is triggered and is located on a metal plate on the opposite side which opposite it is placed the detonator capsule, and the plate thickness at the sensor mounting location is 10-30 mm. 2. The device according to claim 1, characterized in that a sensor with an operating range in the wavelength region covering the visible and infrared parts of the electromagnetic spectrum is used as a chronograph start-up photosensor. 3. A device for determining the response time of an initiator-free detonator capsule having a shock wave tube with a translucent sheath as a pulse conductor from the initiating device, containing a chronograph, a chronograph triggering photosensor that responds to radiation from the detonation wave front passing inside the shock wave tube after it initiation, a chronograph stop photodetector, characterized in that the chronograph start photo sensor is located near the shock wave tube at a distance along its length n less than 30 cm from the initiating device and at a distance of 1 m from the end fixed in the detonator capsule, as a stop chronograph photosensor, it contains a photosensor that responds to radiation when the detonator capsule is triggered and is located near the detonator capsule placed in a metal a sleeve in which a slot is made with a width of at least 5 mm and a length of 3-10 mm. 4. The device according to claim 3, characterized in that a sensor with an operating range in the wavelength region covering the visible and infrared parts of the electromagnetic spectrum is used as a chronograph start-up photosensor. 5. The device according to claim 3, characterized in that a photosensor with a working range in the wavelength region covering the visible and infrared parts of the electromagnetic spectrum is used as a stop chronograph photosensor. 6. The device according to claim 3, characterized in that the chronograph stop photo sensor is equipped with a protective screen from fragments when the detonator capsule is triggered.

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