Shock wave generating device and shock wave generating method

Abstract

To generate a shock wave without using any dangerous materials.SOLUTION: A shock wave generating device comprises a coil 31 with an installation space 3s for installing a metal tube 4 radially formed inside thereof, and a high-voltage pulse generating unit 2 that applies current to the coil 31. When the metal tube 4 is installed in the installation space 3s with its axial direction aligned with that of the coil 31, the shock wave generating device generates an electromagnetic force that compresses the metal tube 4 in the radial direction due to changes in the current applied to the coil 31, and when the metal tube 4 is plastically deformed, a shock wave Ws is generated from one end in the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a shock wave generating device and a shock wave generating method. [Background technology]

[0002] There is a demand for a device that generates shock waves in the air and uses gas to exert a large force at a distant location for purposes such as removing landmines, clearing snow, putting out fires, and exterminating or repelling dangerous or harmful animals, robbers, etc. In response to this demand, a continuous shock wave generator has been disclosed that is configured by connecting a detonation wave generator that generates a detonation wave by igniting a premixed gas that is a mixture of fuel (ethylene, hydrogen, etc.) and an oxidizer (oxygen, nitrous oxide, etc.), and a shock wave reflector that reflects the shock wave obtained from the detonation wave (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-107821 (paragraph 0034, figures 1 and 2) Summary of the Invention [Problem to be solved by the invention]

[0004] However, the storage and handling of hazardous materials such as fuel and oxidizers are restricted by laws and regulations, such as the Fire Service Act, and shock wave generators that use these materials can only be used by a limited number of users in limited locations.

[0005] The present disclosure is intended to solve the above-mentioned problems and aims to generate shock waves without using hazardous materials. [Means for solving the problem]

[0006] The shock wave generator disclosed herein comprises a coil formed radially inside an installation space in which a metal tube is installed, and a power source that applies current to the coil; when the metal tube is installed in the installation space with the axial direction aligned with the coil, an electromagnetic force that compresses the metal tube radially is generated by changes in the current applied to the coil, and when the metal tube is plastically deformed, a shock wave is generated from one end in the axial direction.

[0007] The shock wave generating method disclosed herein is characterized in that a current is suddenly changed to be applied to a coil in which a metal tube is placed radially inside and aligned axially, generating a magnetic force that radially compresses the metal tube, and when the metal tube undergoes plastic deformation, a shock wave is generated from one end in the axial direction. [Effects of the Invention]

[0008] According to the shock wave generating device or shock wave generating method of the present disclosure, shock waves are generated by plastic deformation of a metal tube due to electromagnetic force, so shock waves can be generated without using any hazardous materials. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing the configuration of a shock wave generating device according to a first embodiment. FIG. [Figure 2] 2A to 2E are schematic cross-sectional views showing the states of a shock wave generating unit at each stage, for explaining the operating principle of the shock wave generating device according to the first embodiment. [Figure 3] 4 is a flowchart for explaining the operation of the shock wave generating device according to the first embodiment. [Figure 4] FIG. 2 is a block diagram showing the hardware configuration of a controller of the shock wave generating device of the present disclosure. [Figure 5] 10 is a schematic cross-sectional view of a shock wave generating section for explaining the configuration of a shock wave generating device according to a modified example of the first embodiment. FIG. [Figure 6] 10 is a schematic cross-sectional view of a shock wave generating section for explaining the configuration of a shock wave generating device according to a second embodiment. FIG. [Figure 7] 10 is a schematic cross-sectional view of a shock wave generating section for explaining the configuration of a shock wave generating device according to a third embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiment 1 1 to 3 are diagrams for explaining the configuration and operation of the shock wave generator according to the first embodiment, or the shock wave generation method. Fig. 1 is a block diagram that combines a circuit diagram of the high-voltage pulse generating unit and a schematic cross-sectional view including the axis of the shock wave generating unit to show the configuration of the shock wave generator. Fig. 2A to 2E are schematic cross-sectional views including the axis showing the state of the shock wave generating unit at each stage to explain the operating principle of the shock wave generator. Fig. 3 is a flowchart for explaining the operation of the shock wave generator, i.e., the shock wave generation method.

[0011] 1, the shock wave generator 1 according to the first embodiment includes a shock wave generating unit 3 that generates shock waves by compressing a metal tube 4 with a pulsed magnetic field, and a high-voltage pulse generating unit 2 as a power source that suddenly changes the current applied to a coil 31 of the shock wave generating unit 3. The shock wave generator 1 also includes a controller 6 that controls the operation of the high-voltage pulse generating unit 2.

[0012] The shock wave generating unit 3 includes a coil 31, which is a hollow coil having an installation space 3s inside in the radial direction in which a metal tube 4 is placed, and an insulating support structure 32 that supports the coil 31 and has a bottom 32b that closes one end along the axis X (axial direction) and is cylindrical with a closed end. The metal tube 4 placed in the installation space 3s is cylindrical with an opening 4a formed at at least one end. The material of the metal tube 4 must be electrically conductive and is preferably a non-magnetic material; in this example, aluminum (Al) is used.

[0013] The high-voltage pulse generating unit 2 is configured by connecting a switch 24 to one pole of a power supply 21 and a capacitor 23 that are connected in parallel via a resistor 22, and connecting both poles so that a current can be applied to a coil 31. By opening and closing the switch 24, a high-voltage pulse is applied to the coil 31, causing a sudden change in the current flowing through the coil 31, thereby generating a pulsed magnetic field in the installation space 3s.

[0014] Next, the operation of the shock wave generator 1, i.e., the shock wave generating method, will be described using Figures 2A to 2E and with reference to the flowchart of Figure 3. First, as shown in Figure 2A, the metal tube 4 is installed in the installation space 3s through the opening 32a of the support structure 32 (step S100).

[0015] In this state, as shown in Fig. 2B, the switch 24 is switched from open to closed (step S200). Then, a high-voltage pulse is applied from the high-voltage pulse generator 2 to the coil 31, forming a pulsed magnetic field in the installation space 3s (event P200). The impact electromagnetic force generated by the pulsed magnetic field generates a compressive force Fc toward the axis X on the metal tube 4 (event P210), as shown in Fig. 2C.

[0016] Here, the nature of the high-voltage pulse applied to the coil 31, i.e., the rate of change of the applied current, is set so that the load on the metal tube 4 due to the compressive force Fc is greater than the load at which the metal tube 4 begins to yield. As a result, the diameter of the metal tube 4 decreases due to plastic deformation, that is, the metal tube 4 rapidly deforms in the direction in which the volume of the internal space 4s of the metal tube 4 decreases, and the air in the internal space 4s is compressed.

[0017] Note that the time from event P210 to event P230 when the sudden current change is applied to the coil 31 (step S200) is a short time (instantaneous), ranging from a few microseconds to a few milliseconds. In other words, as the cross-sectional area perpendicular to the axis decreases due to the deformation, the radial deformation speed of the metal tube 4 reaches a level where the flow velocity required for air to escape in the axial direction exceeds the speed of sound, i.e., exceeds the limit of the air movement speed due to the pressure gradient. Therefore, the air in the internal space 4s is compressed instantaneously before the pressure is released by the axial movement driven by the pressure gradient. Furthermore, the opposite side of the opening 4a in the axial direction is blocked by the bottom 32b of the support structure 32. Therefore, a shock wave generated by the instantaneous compression of the air in the internal space 4s is released from the opening 4a (event P230), as shown in FIG. 2D.

[0018] The metal tube 4 that generated the shock wave Ws is irreversibly deformed by plastic deformation, so another metal tube 4 is required to generate the next shock wave Ws. Therefore, the metal tube 4 (deformed metal tube) that has once generated the shock wave Ws is removed from the installation space 3s (step S300), as shown in Fig. 2E. This returns to step S100, allowing the shock wave Ws to be generated repeatedly.

[0019] In other words, compared to methods that involve chemical reactions between hazardous fuel and oxidizer, shock waves can be generated by any user and at any location. Furthermore, because the fuel and oxidizer that undergo chemical reactions are subject to quantitative restrictions when stored or transported, the number of times shock waves can be generated may also be limited. In contrast, there are no particular restrictions on the storage or transportation of the shock wave generator 1 and the metal tube 4 used in the shock wave generation method of the present disclosure, so there is no need to worry about restrictions on the number of times shock waves Ws can be generated.

[0020] As shown in FIG. 4, the controller 6 may be configured by a single piece of hardware 600 including a processor 601 and a storage device 602. Although not shown, the storage device 602 includes a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. Alternatively, a hard disk auxiliary storage device may be included instead of the flash memory. The processor 601 executes a program input from the storage device 602. In this case, the program is input to the processor 601 from the auxiliary storage device via the volatile storage device. The processor 601 may output data such as calculation results to the volatile storage device of the storage device 602, or may store the data in the auxiliary storage device via the volatile storage device.

[0021] Variant. In the above example, the coil and the metal tube have a constant diameter along the axial direction, i.e., are cylindrical, but this is not limiting. In this modified example, a configuration will be described in which the diameter changes along the axial direction so that the diameter on the opening side from which the shock wave is emitted is larger than that on the opposite side. Figure 5 is a schematic cross-sectional view including an axis to explain the configuration of the shock wave generating unit of the shock wave generator according to this modified example.

[0022] 5, in the shock wave generator 1 according to this modification, the metal tube 4 and the coil 31 including the structural support are made into a conical shape with a larger diameter on the opening 4a (right side in the figure) side than on the bottom 32b (left side in the figure). By configuring it so that the opening 4a side is wider, the release range of the shock wave Ws generated in the internal space 4s can be narrowed along the axial direction compared to when it is configured with a constant diameter, and directivity can be improved.

[0023] Embodiment 2 In the above-mentioned first embodiment, no mention is made of the portion beyond the opening of the metal tube. In the second embodiment, an example in which a Laval nozzle is provided beyond the opening will be described. FIG. 6 is a schematic cross-sectional view including an axis for explaining the configuration of the shock wave generating unit of the shock wave generating device according to the second embodiment. In the second embodiment, the configuration of the pulse power supply unit and the basic configuration and operation for generating shock waves are the same as in the first embodiment, and therefore the description of the similar parts will be omitted and FIGS. 1 to 4 of the first embodiment will be used.

[0024] As shown in Fig. 6, the shock wave generator 1 according to the second embodiment has a Laval nozzle 7 provided at the tip of the opening 4a along the axis X. The Laval nozzle 7 has a base (left side in the figure) supported by a support structure 32, and a throttle portion 7s formed between the base and the opening 7a on the opposite side, i.e., in the middle of the axial direction. The airflow containing the shock waves Ws emitted from the opening 4a of the metal tube 4 is accelerated as it passes through the throttle portion 7s, thereby enabling the shock waves Ws to be generated more efficiently.

[0025] Embodiment 3 The shock wave generator according to the third embodiment will be described as an example in which a reflector is provided in a portion beyond the opening of the metal tube, similar to the second embodiment in relation to the first embodiment. Fig. 7 is a schematic cross-sectional view including an axis for explaining the configuration of the shock wave generating unit of the shock wave generator according to the third embodiment. Note that the configuration of the pulse power supply unit and the basic configuration and operation for generating shock waves in the third embodiment are also the same as those in the first embodiment, and therefore the description of the similar parts will be omitted, and Figs. 1 to 4 of the first embodiment will be used.

[0026] As shown in Fig. 7, the shock wave generator 1 according to the third embodiment has a reflector 8 provided at the tip of the opening 4a along the axis X. The base (left side in the figure) of the reflector 8 is supported by a support structure 32, and the opening 8a is provided on the opposite side. The traveling direction of the shock wave Ws emitted from the opening 4a of the metal tube 4 is controlled by the reflector 8, thereby increasing the directionality of the shock wave Ws.

[0027] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0028] For example, in the above example, an insulating support structure 32 is provided between the coil 31 and the metal tube 4, and the installation space 3s is formed inside the support structure 32, but the present invention is not limited to this. The support structure 32 contributes to preventing deformation of the coil 31 in the annular portion and controlling the direction of the shock wave Ws by the bottom portion 32b. However, deformation of the coil 31 may be prevented, for example, by providing rigidity to the coil 31 itself or by using another support member. Furthermore, regarding the direction of emission of the shock wave Ws, for example, the side opposite the opening 4a of the metal tube 4 may be blocked, or in some cases, both ends in the axial direction may be open.

[0029] 1, the circuit of the high-voltage pulse generating unit 2 that applies the high-voltage pulse is not limited to the example shown in FIG. 1 and can be modified as appropriate. Furthermore, if the current applied to the coil 31 is to be suddenly changed, a high-voltage pulse is not necessary. However, as described above, the period required to generate the shock wave Ws, i.e., to plastically deform the metal tube 4, is several milliseconds or less, and the current during other periods is wasted. Therefore, from the viewpoint of power efficiency, it is preferable to apply the high voltage in pulses.

[0030] Furthermore, a series of steps from installing the metal tube 4 in the installation space 3s (step S100), applying a sudden change in current to the coil 31 (step S200), and removing the metal tube 4 (step S300) may be automatically performed by controlling a mechanism (not shown) with the controller 6. In this case, the orientation of the shock wave generating unit 3 (strictly speaking, the opening 4a) may also be automatically changed depending on the target to be hit by the shock wave Ws.

[0031] As described above, the shock wave generator 1 of the present disclosure includes a coil 31 formed radially inside an installation space 3s in which a metal tube 4 is installed, and a power source (high-voltage pulse generator 2) that applies current to the coil 31. When the metal tube 4 is installed in the installation space 3s with its axial direction (direction of axis X) aligned with that of the coil 31, a change in current applied to the coil 31 generates an electromagnetic force that compresses the metal tube 4 radially. When the metal tube 4 plastically deforms, shock waves Ws are generated from one end of the axial direction. This allows shock waves to be generated without using hazardous materials (such as those regulated by the Fire Service Act). Therefore, shock waves Ws can be generated regardless of the user or location. Furthermore, unlike hazardous materials, there are no restrictions on the amount of storage or transportation of the metal tube 4, and therefore no restrictions on the number of times shock waves Ws can be generated.

[0032] In particular, if a pulse power supply (high voltage pulse generating unit 2) that generates a pulse voltage is used as the power supply, the amount of power used can be minimized and shock waves Ws can be generated efficiently.

[0033] Furthermore, if one end (opening 4a) of the installation space 3s is open to allow the metal tube 4 to be inserted and removed, shock waves Ws can be easily generated multiple times simply by replacing the metal tube 4.

[0034] If the installation space 3s and the coil 31 are configured so that the diameter increases along the axial direction toward one end (opening 4a), the directivity of the shock wave Ws can be increased.

[0035] If a support structure 32 is provided that supports the coil 31 from the inside in the radial direction, the shape of the coil 31 is stabilized.

[0036] If the support structure 32 is formed into a cylindrical shape with the other axial end (bottom 32b) closed, the direction of emission of the shock wave Ws can be restricted to the opening 4a side.

[0037] For example, if a Laval nozzle 7 is provided on one end of the support structure 32 or of a non-exemplified member surrounding the installation space 3s, the Laval nozzle 7 is connected to the installation space 3s and extends in the axial direction away from the installation space 3s, thereby increasing the flow velocity and efficiently generating shock waves Ws.

[0038] Alternatively, for example, if an annular reflector 8 is provided on one end side of the support structure 32 or of an unexemplified member surrounding the installation space 3s, the reflector 8 is connected to the installation space 3s and extends in the axial direction away from the installation space 3s, thereby improving the directionality of the shock wave Ws.

[0039] As described above, according to the shock wave generating method of the present disclosure, a current is suddenly changed to be applied to the coil 31, in which the metal tube 4 is placed with its axial direction (direction of axis X) aligned radially inward, to generate a magnetic force that radially compresses the metal tube 4. When the metal tube 4 undergoes plastic deformation, a shock wave Ws is generated from one end in the axial direction. This makes it possible to generate shock waves without using hazardous materials (which are regulated by the Fire Service Act, etc.). Therefore, shock waves Ws can be generated by any user and at any location. Furthermore, unlike hazardous materials, there are no restrictions on the amount of storage or transportation of the metal tube 4, and therefore there are no restrictions on the number of times shock waves Ws can be generated.

[0040] In this case, if a sudden change in current is caused by a pulsed high voltage, the amount of power used can be minimized and shock waves Ws can be generated efficiently.

[0041] If a non-magnetic material (for example, aluminum) is used for the metal tube 4, it can be plastically deformed more efficiently.

[0042] Various aspects of the present disclosure are summarized below as appendices.

[0043] (Appendix 1) A coil in which an installation space for installing a metal pipe is formed radially inside; and a power source that applies a current to the coil; When the metal tube is installed in the installation space with its axial direction aligned with that of the coil, a change in current applied to the coil generates an electromagnetic force that compresses the metal tube in the radial direction, and when the metal tube undergoes plastic deformation, a shock wave is generated from one end in the axial direction of the shock wave generator.

[0044] (Appendix 2) The shock wave generating device according to claim 1, wherein the power supply is a pulse power supply that generates a pulse voltage.

[0045] (Appendix 3) The shock wave generating device according to claim 1 or 2, wherein the one end of the installation space is open for inserting and removing the metal tube.

[0046] (Appendix 4) 4. The shock wave generating device according to any one of claims 1 to 3, wherein the installation space and the coil have diameters that increase axially toward the one end.

[0047] (Appendix 5) 5. The shock wave generating device according to any one of claims 1 to 4, further comprising a support structure that supports the coil from the radially inner side.

[0048] (Appendix 6) 6. The shock wave generating device according to claim 5, wherein the support structure is a cylindrical body having a bottom and a closed axial end.

[0049] (Appendix 7) 7. The shock wave generator according to claim 1, wherein a Laval nozzle is provided at the one end, the Laval nozzle communicating with the installation space and extending in an axial direction away from the installation space.

[0050] (Appendix 8) The shock wave generating device according to any one of claims 1 to 6, characterized in that an annular reflector is provided on the one end side, communicating with the installation space and extending in an axial direction away from the installation space.

[0051] (Appendix 9) A shock wave generating method characterized by suddenly changing the current applied to a coil in which a metal tube is placed radially inside and aligned axially, generating a magnetic force that radially compresses the metal tube, and generating a shock wave from one end in the axial direction when the metal tube undergoes plastic deformation.

[0052] (Appendix 10) 10. The shock wave generating method according to claim 9, wherein the sudden change in current is caused by a pulsed high voltage.

[0053] (Appendix 11) 11. The shock wave generating method according to claim 9 or 10, wherein the metal tube is made of a non-magnetic material. [Explanation of symbols]

[0054] 1: shock wave generator, 2: high voltage pulse generator, 3: shock wave generator, 31: coil, 32: support structure, 32b: bottom, 3s: installation space, 4: metal tube, 6: controller, 7: Laval nozzle, 8: reflector, Ws: shock wave, X: axis.

Claims

1. A coil in which an installation space for installing a metal pipe is formed radially inside; and a power source that applies a current to the coil; When the metal tube is installed in the installation space with its axial direction aligned with that of the coil, a change in current applied to the coil generates an electromagnetic force that compresses the metal tube in the radial direction, and when the metal tube is plastically deformed, a shock wave is generated from one end in the axial direction.

2. 2. The shock wave generating device according to claim 1, wherein the power source is a pulse power source that generates a pulse voltage.

3. 3. The shock wave generating device according to claim 1, wherein the one end of the installation space is open for inserting and removing the metal tube.

4. 3. The shock wave generator according to claim 1, wherein the diameter of the installation space and the coil increases axially toward the one end.

5. 3. The shock wave generating device according to claim 1, further comprising a support structure for supporting the coil from the inside in the radial direction.

6. 6. The shock wave generating device according to claim 5, wherein the support structure has a cylindrical shape with a closed end and the other axial end is closed.

7. 3. The shock wave generator according to claim 1, wherein a Laval nozzle is provided at the one end, the Laval nozzle communicating with the installation space and extending in an axial direction away from the installation space.

8. 3. The shock wave generating device according to claim 1, wherein an annular reflector is provided on the one end side, the reflector communicating with the installation space and extending in an axial direction away from the installation space.

9. A shock wave generating method characterized by suddenly changing the current applied to a coil in which a metal tube is placed radially inside and aligned axially, generating a magnetic force that radially compresses the metal tube, and generating a shock wave from one end in the axial direction when the metal tube undergoes plastic deformation.

10. 10. The shock wave generating method according to claim 9, wherein the sudden change in the current is caused by a pulsed high voltage.

11. 11. The shock wave generating method according to claim 9, wherein the metal tube is made of a non-magnetic material.

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