Pressure wave generator and method of operating a pressure wave generator

Abstract

A method for operating a pressure wave generator (1) with a pressure chamber (2), the pressure wave generator (1) comprising a closure element (9) which, in a closed position, closes the pressure chamber (2) against an outlet (15) and, in an open position, allows a working medium to flow from the pressure chamber (2) to the outlet (15), and an actuator by means of which the closure element (9) can be brought from the closed position to the open position, in particular also from the open position to the closed position, the method comprising the repeated steps of filling the pressure chamber (2) with a gaseous working medium at a pressure of more than 100 bar, moving the actuator to move the closure element (9) in the opening direction to open the pressure chamber (2) against the outlet (15), and discharging the pressurized working medium from the pressure chamber (2) via the outlet (15) within a discharge period of less than 15 milliseconds.

Description

Technical Field

[0001] The present invention relates to a device and a method for generating high-intensity pressure pulses. In particular, it relates to a pressure wave generator and a method of operating the pressure wave generator as described in the preamble of the independent patent claims.

[0002] As described in WO 2007 / 028264, in particular WO 2010 / 025574, in a pressure wave generator, an auxiliary explosion and a main explosion are ignited in chambers separated from each other. The auxiliary explosion acts to release the shutter of the main explosion chamber directly or via another latching mechanism, so that the subsequent main explosion acts on the shutter with full force and does not damage or destroy the shutter accordingly. An explosion delay occurs between the auxiliary explosion and the main explosion. Such a delay is caused, for example, by a delay line through which the explosion is conducted from the auxiliary chamber to the main chamber, or by delayed ignition in the two chambers via a separate ignition device present in the chamber.

[0003] A simplified pressure wave generator is needed.

[0004] Therefore, a possible object of the present invention is to provide a simplified pressure wave generator with respect to known devices.

[0005] A further possible object of the present invention is to provide a more robust and / or durable pressure wave generator compared to known devices.

[0006] At least one of these objects is solved by the pressure wave generator and the method of operating the pressure wave generator described in the claims.

[0007] A method for operating a pressure wave generator having a pressure chamber, the pressure wave generator comprising · a closing element which, in the closed position, closes the pressure chamber against the outlet and, in the open position, allows the working medium to flow from the pressure chamber into the outlet; · An actuator that can bring a closing element from a closed position to an open position, and in particular, can also bring it from the open position to the closed position; Here, this method includes repeatedly performing the following steps: · Filling the pressure chamber with a gas operating medium at a pressure exceeding 100 bar; and · Moving the actuator, thereby moving the closing element in the opening direction to open the pressure chamber with respect to the outlet, and discharging the pressurized operating medium from the pressure chamber through the outlet within a discharge time of less than 15 milliseconds.

[0008] During the discharge time, the pressure in the pressure chamber has dropped to ambient pressure.

[0009] In an embodiment, the volume of the pressure chamber is 3 liters or more, more specifically 4 liters or more, and more specifically 5 liters or more.

[0010] In an embodiment, the area at the narrowest point of the outlet is greater than 20 square centimeters, more specifically greater than 80 square centimeters, and more specifically greater than 180 square centimeters.

[0011] In the case of a circular outlet, the above value obtained by rounding the area of the narrowest point with respect to the diameter corresponds to a diameter exceeding 5 cm, particularly exceeding 10 cm, and particularly exceeding 15 cm.

[0012] In an embodiment, the opening speed of the closing element is greater than 10 meters per second, more specifically greater than 20 meters per second, and more specifically at least 30 meters per second.

[0013] In an embodiment, the stroke of the closing element during the opening and closing movement is 30 to 150 mm, particularly 40 to 100 mm, and particularly 50 to 80 mm.

[0014] In an embodiment, the filling of the operating medium into the pressure chamber is performed at a pressure exceeding 150 bar, particularly at a pressure exceeding 200 bar.

[0015] In an embodiment, the discharge duration is less than 10 milliseconds, more specifically less than 5 milliseconds, and even more specifically less than 3 milliseconds.

[0016] In an embodiment, the working medium is one of air, nitrogen, and steam, particularly superheated steam or saturated steam.

[0017] In an embodiment, this method includes the following steps that are performed after filling and before opening the pressure chamber. · Specifically, when flowing through a circulation line connected to the pressure chamber, particularly when the working medium is conveyed through the circulation line by a circulation blower, heating the working medium placed in the pressure chamber.

[0018] In an embodiment, this method includes the following steps that are performed during the filling of the pressure chamber. · Specifically when flowing through the working medium filling line, heating the working medium supplied to the pressure chamber.

[0019] In an embodiment, the working medium is heated to a temperature of 150°C to 250°C, particularly 230°C, or 200°C to 450°C, particularly 250°C.

[0020] Relatively speaking, the heating can be performed, for example, by a temperature difference exceeding 100°C, particularly exceeding 200°C, particularly exceeding 300°C, and in certain situations exceeding 400°C. The heating can be performed, for example, using an electric heating element. The outflow rate and the pulse of the outflowing working medium increased with the square root of the temperature.

[0021] Another effect of heating the working medium is that it can prevent the working medium from cooling too much when it flows out of the pressure chamber. When the working medium flows out, it relaxes to the ambient pressure and can thus be cooled to a temperature below its liquefaction temperature, depending on the situation and which working medium is present. As a result, the jet spreads subsonically after discharge, limiting the impact of the device.

[0022] In an embodiment, there is a heater, in particular an electric heater, configured to heat the working medium in the pressure chamber.

[0023] In an embodiment, a heater is provided that is arranged in the working medium filling line to heat the working medium.

[0024] In an embodiment, the heater is a heat exchanger, in particular a heat exchanger element, in particular an electrically heated heat exchanger element.

[0025] In an embodiment, the method is carried out using a pneumatic actuator, which · has a first piston surface acting on a gaseous control medium in a first volume, wherein the pressure in the first volume generates an actuator force on the first piston surface in a first direction, the first piston surface; · has a second piston surface acting on a control medium in a second volume, wherein the pressure in the second volume generates an actuator force on the second piston surface in a second direction opposite to the first direction, the second piston surface; comprises The closing element can be brought from the closed position to the open position by the pneumatic actuator and, in particular, can also be brought from the open position to the closed position; The method of opening the pressure chamber is · a step of discharging at least a part of the control medium from the first volume, in particular a step of opening the pressure chamber by opening the inlet / outlet port of the first volume; · The pressure drop in the first volume is faster than that in the second volume. By moving the actuator in the second direction, the closing element is moved in the opening direction to open the pressure chamber to the outlet, and the working medium is discharged from the pressure chamber through the outlet. This is a step. It includes.

[0026] In an embodiment, this method is performed using a pneumatic actuator. The pneumatic actuator · A first piston surface that acts on the gaseous control medium in the first volume, where the pressure in the first volume generates an actuator force on the first piston surface in the first direction. This is the first piston surface. · A second piston surface that acts on the control medium in the second volume, where the pressure in the second volume generates an actuator force on the second piston surface in the second direction opposite to the first direction. This is the second piston surface. It comprises.

[0027] Using a pneumatic actuator, the closing element can be moved from the closed position to the open position, especially from the open position to the closed position.

[0028] This method includes repeating the following steps. a) A step of filling the first volume with a pressurized gaseous control medium, especially a step of filling using a filling valve, such as a compressed air valve. b) By compensating the pressure between the first volume and the second volume with a throttle, due to the difference in area between the first piston area and the second piston area, moving the actuator in the first direction to move the closing element in the closing direction to close the pressure chamber. c) A step of filling the pressure chamber with a gaseous working medium. d) A step of discharging at least a part of the control medium from the first volume, especially by opening the inlet / outlet port of the first volume, thereby opening the pressure chamber. And e) The pressure drop in the first volume is faster than the pressure drop in the second volume, causing the actuator to move in the second direction, thereby moving the closing element in the opening direction to open the pressure chamber to the outlet and discharging the working medium from the pressure chamber through the outlet.

[0029] Steps a), b) and c) can be performed simultaneously or with temporal overlap. Step d) is usually performed after steps a), b) and c). In step d), the opening of the pressure chamber triggered by the opening of the inlet / outlet port directly transitions to step e).

[0030] In an embodiment, for example, the duration between the start of the opening movement of the closing element and the maximum opening of the closing element due to the actuation of the discharge solenoid valve is in the range of 20 milliseconds to 120 milliseconds, particularly in the range of 40 milliseconds to 60 milliseconds.

[0031] In an embodiment, the duration for opening the closing element is thereby less than 10 milliseconds, particularly less than 5 milliseconds, particularly less than 3 milliseconds. It may be substantially the same as the discharge time.

[0032] The pressure wave generator according to the first aspect is used to perform the method described above.

[0033] This includes a pressure chamber and · a closing element that closes the pressure chamber against the outlet in the closed position and allows the working medium to flow from the pressure chamber into the outlet in the open position; · an actuator capable of moving the closing element from the closed position to the open position and from the open position to the closed position; and · the volume of the pressure chamber is 3 liters or more, particularly 4 liters or more, particularly 5 liters or more; · particularly the volume of the pressure chamber is less than 15 liters; · Those with an area at the narrowest point of the outlet exceeding 20 square centimeters, especially those exceeding 80 square centimeters, especially those exceeding 180 square centimeters; · The stroke of the closing element during the opening and closing movement is 30 - 150 mm, especially 40 - 100 mm, especially 50 - 80 mm.

[0034] As a result, the pressure wave generator can generate an outlet jet that generates the maximum possible maximum pressure or the maximum possible force there after the free jet expansion in free space. For this purpose, the mass flow rate generated by the pressure wave generator is made as large as possible. The mass flow rate is proportional to the density of the working medium, the outlet velocity, and the area of the outlet opening. Therefore, starting from a predetermined filling pressure of the gas working medium in the pressure chamber, a combination of parameters can be determined within the defined limits for generating the maximum pressure of the outlet jet.

[0035] In an embodiment, the closing area of the closing opening that is closed and opened by the closing element respectively is at least the same size as the area at the narrowest point of the outlet, especially at least 10% larger than the area at the narrowest point of the outlet.

[0036] This is in contrast to a normal valve where the valve forms the narrowest point. At the narrowest cross-section, the gas flows at the speed of sound. If this point is not at the end of the outlet, a supersonic flow will occur after the narrowest point. This brings a compression shock to the outlet and hinders the performance of the device. This is prevented by expanding the outlet jet outside the outlet.

[0037] In an embodiment, the closing element is in a hollow cylindrical shape and is arranged to close or open a closing opening corresponding to the cylindrical surface.

[0038] With a hollow cylindrical design, the mass of the closing element can be reduced. Furthermore, the annular surface of the piston surrounding the hollow cylindrical recess determines the rebound force with which the escaping gas pushes the piston back. In an embodiment, when viewed in cross-section, the area of the hollow cylindrical recess is 25% or more, particularly 50% or more, of the area of the closing element. The cylindrical closing surface can vary the area of the closing surface greatly as a function of the closing movement.

[0039] In an embodiment, the total area on the closing element where the pressurized working medium exerts a force on the closing element in the closing direction is less than 10% of the cross-sectional area of the outlet at the point where the outlet is closed by the closing element.

[0040] In an embodiment, the area of the inlet / outlet opening of the first volume is 200 square millimeters to 500 square millimeters, or at most 1500 square millimeters. In the case of a circular cross-section of the opening, this corresponds to a circular diameter of 16 mm to 25 mm, or at most 44 mm. This enables the first volume to be emptied sufficiently quickly, and thus a rapid opening movement corresponding thereto becomes possible. As a result, it has been found that these diameters hardly depend on the first piston area, i.e., the piston area within the first volume.

[0041] In an embodiment, during the opening movement of the closing element, starting from the end position where the closing element closes the closing opening, the closing element opens the closing opening only after covering a minimum distance. This distance is different from zero. In particular, this distance is 5 millimeters or more or 8 millimeters or more.

[0042] A pressure wave generator according to a second aspect is used to carry out the above method. This includes a pressure chamber and · a closing element that closes the pressure chamber against the outlet in the closed position and enables the working medium to flow from the pressure chamber into the outlet in the open position, and · an actuator that can move the closing element from the closed position to the open position and from the open position to the closed position. · A heater configured to heat the working medium supplied to the pressure chamber or the working medium present in the pressure chamber, in particular an electric heater, and comprises.

[0043] In particular, a pneumatic actuator for use in a pressure wave generator · A first piston surface acting on the gas control medium in the first volume, wherein the pressure in the first volume generates an actuator force on the first piston surface in the first direction, and · A second piston surface acting on the control medium in the second volume, wherein the pressure in the second volume generates an actuator force on the second piston surface in a second direction opposite to the first direction, and · A throttle between the first volume and the second volume, and · A first volume inlet / outlet port for introducing the control medium into the first volume and discharging the control medium from the first volume, and comprises, · The first piston area is larger than the second piston area.

[0044] In an embodiment, the pneumatic actuator has end position damping, in particular by closing the inlet / outlet opening. Thereby, the inlet / outlet opening is closed with respect to the first volume.

[0045] In an embodiment, the piston closing element is configured to close the inlet / outlet opening. Thereby, end position damping can be easily realized by an element of the piston itself.

[0046] In a method of operating a pneumatic actuator, the following steps are performed. · Filling the first volume with a pressurized gas control medium, in particular filling using a filling valve, such as a compressed air valve, · Moving the actuator in the first direction by the surface difference between the first piston surface and the second piston surface due to pressure compensation between the first volume and the second volume by the throttle · By opening the inlet / outlet port in particular, discharging at least a part of the control medium from the first volume, and · By making the pressure drop in the first volume faster than the pressure drop in the second volume, moving the actuator in the second direction.

[0047] In this way, the reciprocating motion of the actuator can be realized by simple means of only the filling valve and the inlet / outlet opening. This is, on the one hand, the result of the surface difference between the piston surfaces, and on the other hand, the result of the throttle between the two volumes.

[0048] The inlet / outlet opening can be made relatively large so as to cause a rapid pressure drop within the first volume.

[0049] In an embodiment, the piston closing element is also configured to isolate the control medium filling line from the first volume. Thereby, a high-pressure surge in the filling line can be avoided.

[0050] In an embodiment, the two volumes are realized as part of a common working chamber of a cylinder in which a single piston is arranged and two piston surfaces are formed thereon.

[0051] Thereby, the seal of the piston to the (now common) cylinder becomes unimportant. There may be a gap between the piston and the cylinder. This has a throttling function between the two volumes. Therefore, pressure compensation is performed through this gap. Thereby, the design can be further simplified. Thus, in an embodiment, the throttle is formed by the gap between the cylinder and the piston. Thereby, a conventional seal for the piston becomes unnecessary.

[0052] In another embodiment, the two volumes and the piston surfaces are on separate pistons in separate cylinders, and the two separate pistons are mechanically coupled and their movements are also coupled.

[0053] In an embodiment, a piston closing element for closing the first piston surface and the inlet / outlet opening is formed on the same piston. This enables a particularly simple and reliable design.

[0054] In an embodiment, the pneumatic actuator comprises a cylinder discharge valve for rapidly discharging the control medium from the first volume by opening the inlet / outlet port. The cylinder discharge valve has a piston surface on which a force is generated to close the cylinder discharge valve when the control medium is applied, and a valve surface on which a force is generated in the opening direction of the cylinder discharge valve when the control medium is applied, and the valve surface is smaller than the piston surface. In this way, by applying the same pressure to both surfaces, the cylinder discharge valve can be closed and held in the closed position.

[0055] In an embodiment, the pneumatic actuator includes a discharge pilot valve for discharging the control medium from a discharge valve volume in which the control medium acts on the piston surface. This can be used to create an instantaneous and temporary pressure imbalance between the two surfaces, thereby opening the cylinder discharge valve.

[0056] In an embodiment, the control medium filling line is configured to fill both the discharge valve volume and the first volume with the control medium under the same pressure. Thus, on the one hand, the same pressure can be achieved within the two volumes, and on the other hand, a temporary imbalance can be realized by the filling line that acts as a throttle between the two volumes.

[0057] The pressure in the control medium is, for example, 50 to 140 bar, particularly 80 to 100 bar.

[0058] In an embodiment, a part of the control medium filling line through which the control medium is supplied to the first volume flows through the cylinder discharge valve, particularly through the plug of the valve. For example, this section is a passage within the plug that allows a small flow through the valve even in the closed position of the valve.

[0059] In an embodiment, a portion of the control medium filling line through which the first volume is supplied together with the control medium extends through the housing of the pressure wave generator.

[0060] In an embodiment, the linear guide of the piston surrounds the rear closure guide and consists of a piston that can move linearly along the rear closure guide in the direction of movement, and a hollow cylindrical piston connecting element that surrounds the bearing element fixed to the rear closure guide and extends away from the piston in the direction of movement. Here, the second volume is formed between the piston, the inner surface of the piston connecting element, the bearing element, and the rear closure guide. Typically, the rear closure guide is connected and fixed to the housing.

[0061] Therefore, as an extension of the hollow cylindrical piston connecting element, the hollow cylindrical element can be driven, which is advantageous in certain applications. For example, in the case of a pressure wave generator having the hollow cylindrical closing element described here.

[0062] Further preferred embodiments are shown in the dependent patent claims. The features of the method claims can be combined with the apparatus claims with the necessary modifications, and vice versa.

[0063] In particular, the pressure wave generator can have a controller configured to control the pressure wave generator in order to execute the method described in at least one of the method claims. This control is performed by controlling at least the valve of the pressure wave generator.

Brief Description of the Drawings

[0064] Hereinafter, the subject matter of the present invention will be described in more detail based on the preferred embodiments shown in the accompanying drawings. They are shown schematically.

Figure 1

Figure 2

Figure 3

Figure 4

[0065] DETAILED DESCRIPTION OF THE INVENTION

[0066] FIGS. 1 and 2 each show a pressure wave generator 1 provided with a pressure chamber 2. The closing element 9 is arranged to close the pressure chamber 2 on the opposite side of the outlet 15.

[0067] The closing element 9 is guided on a bearing element 14 that enables a linear opening and closing movement of the closing element 9. In the embodiment of FIG. 1, the closing element 9 is hollow cylindrical and has a piston guided by a bearing element 14 connected and fixed to the housing 16. In the embodiment of FIG. 2, the closing element 9 is hollow cylindrical and surrounds a bearing element 14 connected and fixed to the housing 16. The direction of movement indicated by the double arrow is typically the longitudinal direction of the pressure wave generator 1 and the outflow direction in which the working medium flows out of the outlet 15. FIGS. 1 and 2 show the closing element 9 in the closed position, i.e., the pressure chamber 2 is closed with respect to the outlet 15.

[0068] The outlet 15 is used for the directional discharge of the working medium. Thereby, a pressure wave can be generated.

[0069] In the open position, the closing element 9 releases the closing surface of the closing opening. In the closed position, the closing opening is closed by the closing element 9. Here, the closing surface is the closing surface of the cylinder. The pressure chamber 2 is annular. The pressure chamber 2 surrounds the closing element 9. The closing opening starts from the pressure chamber 2 and leads radially inwards with respect to the annular pressure chamber 2. The working medium flowing out through the closing opening flows radially inwards and then axially with respect to the annular pressure chamber 2 through the outlet 15.

[0070] In the closed state, the closing element 9 is in contact with the valve seat of the housing 16. The valve seat can be designed to have a collar, which means that when the closing element is moved in the opening direction starting from the end position of the closed position, only the closing opening is opened, and after the closing element 9 has covered a certain distance, the working medium flows out. This path is shown as the collar width 77. Thereby, the movement of the closing element 9 can be accelerated before the closing opening is opened, and the closing opening can be quickly opened to allow the working medium to flow out rapidly.

[0071] The size of the closing area is larger than the area of the outlet or the outlet area, that is, the cross-sectional area where the outlet merges into the free space. In particular, the outlet 15 corresponds to the narrowest point along the path of the working medium emerging from the pressure chamber 2. As a result, the velocity of the flowing working medium is highest at the outlet 15 or immediately behind it. In particular, thereby, the flowing working medium reaches the speed of sound only immediately behind the narrowest point, that is, immediately behind the outlet 15. This is advantageous for the operation of the device.

[0072] The first filling line or the working medium filling line 12 is arranged to fill the pressure chamber 2 with the working medium. It is sent by the working medium valve 10.

[0073] In the method of operating the device, · The pressure chamber 2 is closed by the closing element 9 with respect to the outlet 15, · The pressure chamber 2 is filled with the working medium under high pressure, that is, under a pressure exceeding 100 bar, in particular exceeding 150 bar, especially exceeding 200 bar, · The pressure chamber 2 is rapidly opened so that the energy stored in the working medium is converted into kinetic energy over as short a period as possible. The shorter the period, the greater the velocity and momentum of the flowing working medium, and the greater the effect of the pressure wave.

[0074] In an embodiment, the following parameters are implemented. Pressure: 100 bar to 300 bar Volume: 3 to 15 liters Outlet area: 50 cm 2 ~320 cm 2 (= diameter of approximately 80 - 200 mm) Opening speed: 15 m / s to 40 m / s Stroke: 50 mm to 100 mm

[0075] In the embodiment, the following parameters are implemented. Pressure: over 120 bar Volume: 4 liters Outlet area: 80 cm 2 (equivalent to a diameter of approximately 100 mm) Opening speed: over 15 m / s Stroke: 60 mm

[0076] In the embodiment, the following parameters are implemented. Pressure: 250 bar to 300 bar, particularly 280 bar Volume: 8 to 12 liters, particularly 10 liters Outlet area: 150 cm 2 ~210 cm 2 , particularly 180 cm 2 (equivalent to a diameter of approximately 150 mm). Opening speed: over 25 m / s Stroke: 60 mm to 90 mm, particularly 75 mm

[0077] In the embodiment, the following parameters are implemented. Pressure: 250 bar to 300 bar, particularly 280 bar Volume: 4 to 6 liters, particularly 5 liters Outlet area: 60 cm 2 ~80 cm 2 , particularly 70 cm 2 (equivalent to a diameter of approximately 95 mm) Opening speed: over 20 m / s Stroke: 50 mm to 70 mm, particularly 60 mm

[0078] In all embodiments, it is possible to heat the working medium to a temperature from 150 °C to 250 °C, particularly up to 230 °C, or to a temperature from 200 °C to 450 °C, particularly up to 250 °C.

[0079] The opening movement of the closing element 9 is effected by an active gas spring or a pneumatic actuator 4b. This has a cylindrical working chamber 43 and a piston 93 which moves therein, the movement of which is coupled to the movement of the closing element 9, in particular by being connected and fixed to one another, in particular by being integrally formed. In the embodiments of FIGS. 1 and 2, the coupling is effected by a piston connecting element 94. This is a piston rod in FIG. 1 and a hollow cylinder in FIG. 2.

[0080] The piston 93 divides the working chamber 43 into a first volume 41 and a second volume 42. The inner cylinder wall 44 of the working chamber 43 and the piston 93 are not sealed. In particular, there may be a small gap, hereinafter referred to as the piston gap 96. This enables gas exchange between the two volumes and in particular functions as a throttle. In other embodiments, a separate conduit can be arranged between the first volume 41 and the second volume 42 and can have a throttle enabling gas exchange in addition to or as an alternative to the piston gap 96. Also, such a throttle can be implemented as a piston throttle 100 through one or more holes through the piston 93, thereby also enabling gas exchange between the two volumes.

[0081] The gas pressure of the control medium in the first volume 41 generates a force in the direction of the opening movement of the closing element 9, so that the effective surface in this case is the first piston surface 91.

[0082] The gas pressure of the control medium in the second volume 42 generates a force in the direction of the opening movement of the closing element 9, so that the effective surface in this case is the second piston surface 92.

[0083] Here, the second piston area 92 is smaller than the first piston area 91, for example at least 5% or 10% or 20% smaller.

[0084] The piston 93 has a piston closing element 95, which closes the cylinder inlet / outlet 45 or the inlet / outlet opening of the first volume 41 during the opening movement. The cylinder inlet / outlet 45 is depicted concentrically here with the working chamber 43, but could alternatively be arranged laterally. By closing the cylinder inlet / outlet 45, braking or end position damping of the opening movement is effected. At the same time, the compressed air valve 49 is also protected from pressure surges through the compressed air filling line 48.

[0085] The cylinder inlet / outlet 45 can be opened by the cylinder discharge valve 46. The control medium flows out, for example, through the discharge line or vent line 102. The cylinder discharge valve 46 can have a relatively large valve cross-section compared to the filling line. Thereby, a rapid pressure reduction in the first volume 41 can be achieved. The cylinder discharge valve 46 is held in the closed state by the pressure in the compressed air filling line 48. This pressure can be reduced by opening the discharge pilot valve 47. Thus, by opening the bleed pilot valve, the opening movement of the closing element is initiated.

[0086] The cylinder discharge valve 46 is, for example, a poppet valve with a movable plug. The plug has a piston surface 52 on which compressed air from the compressed air filling line 48 acts within the discharge valve volume 51. The valve surface 53, which is acted upon by the pressure in the cylinder inlet / outlet 45, is smaller than the piston surface 52, and the forces between the piston surface 52 and the valve surface 53 are opposite to each other. When the discharge pilot valve 47 is closed, the gas pressures on the two surfaces are the same, and the force on the piston surface 52 is greater than the force on the valve surface 53, which holds the plug or the cylinder discharge valve 46 in the closed position.

[0087] Also, the compressed air filling line 48 feeds the first volume 41 via a part 101 of the compressed air filling line 48. The compressed air filling line 48 is fed through the compressed air valve 49.

[0088] The ventilation line 97 equalizes the pressure between the ambient air and the intermediate cylinder. The intermediate cylinder is placed between the rear end portion of the closing element 9 and the active gas spring or the pneumatic actuator 4b.

[0089] In the variant of FIG. 1, the working chamber 43 and the piston 93 are realized compactly. However, the same operating mode can also be realized by separate first and second volumes and a separate piston having different piston areas. In this case, a line having a throttle is arranged between the two volumes, and the movements of the two pistons are mechanically coupled. That is, when one of the two pistons moves linearly, the other piston always moves linearly as well.

[0090] In the embodiments of FIGS. 1 and 2, the piston stroke can be, for example, between 20 mm and 150 mm, particularly between 30 mm and 80 mm. The diameter of the piston can be, for example, between 20 mm and 200 mm, particularly between 40 mm and 120 mm.

[0091] In the embodiment, a heating element 99 is provided. This can be used to heat the pressure-actuating medium in the pressure chamber 2. Thereby, the energy of the generated pressure wave can be increased.

[0092] FIGS. 1 and 2 show a pneumatic actuator 4b combined with a pressure wave generator 1.

[0093] In the operation of this variant, the following method steps can be performed.

[0094] · Open the compressed air valve 49 with the discharge pilot valve 47 closed. This has the following effects. The pressure in the compressed air filling line 48 (e.g., 70 bar) closes the cylinder discharge valve 46. The first volume 41 is pressurized with compressed air via the compressed air filling line 48. Also, the second volume 42 is pressurized via the piston clearance 96, and the same pressure exists in both volumes over time. Since the first piston area 91 is larger than the second piston area 92, the piston 93, and thus the closing element 9, is moved to the closed position (with respect to the direction of the opening movement).

[0095] · Close the compressed air valve 49. The closing element 9 remains in the closed position.

[0096] · Open the working medium valve 10, thereby filling the pressure chamber 2.

[0097] · Trigger the opening movement by opening the cylinder discharge valve 46 (this can be done, in particular, by opening the discharge pilot valve 47 and reducing the pressure in the compressed air filling line 48). When the cylinder discharge valve 46 is opened, the pressure in the first volume 41 decreases. The pressure in the second volume 42 also decreases, but more slowly than in the first volume 41 due to the throttling effect of the piston clearance 96. This causes the force on the second piston surface 92 to become greater than the force on the first piston surface 91. Thereby, the piston 93 moves and the closing element 9 opens.

[0098] · Before the piston 93 or the closing element 9 stops, the piston closing element 95 closes the cylinder inlet / outlet 45. The air remaining in the (now smaller) first volume 41 is compressed, slowing down the movement of the piston 93 and the closing element 9. The compressed air valve 49 is prevented from being stressed by the pressure peak.

[0099] · The working medium flows out through the opening released by the closing element 9.

[0100] · By closing the discharge pilot valve 47 in particular, the cylinder discharge valve 46 is closed. This can be done when the piston area is larger than the area on which the compressed air acts in the opposite direction to the cylinder discharge valve 46 or its plug. The piston area is such that the compressed air in the compressed air filling line 48 presses the cylinder discharge valve 46 or its plug into the closed position. After closing the cylinder discharge valve 46, the pressure in the first volume 41 may be high enough (e.g., 20 bar) even after pressure compensation with the second volume 42 to retract the piston 93 and move the closing element 9 to the closed position.

[0101] · Thereafter, by opening the compressed air valve 49, the procedure can be started again.

[0102] When using the pneumatic actuator 4b as described above, moving the opening and closing element in the opening direction is done by moving the pneumatic actuator in the second direction. Moving the closing element in the closing direction is done by moving the pneumatic actuator in the first direction.

[0103] Figure 2 shows an embodiment having a pneumatic actuator 4b different from that shown in Figure 1. It is also possible to use the entire pneumatic actuator shown in Figure 2, or only individual elements, namely, · the piston throttle 100 and / or · the closing element 9 having a hollow cylinder instead of the piston rod as the piston connecting element 94 and / or · the cylinder discharge valve 46 having a section 101 of the compressed air filling line, which is combined with the pressure wave generator 1 as shown in Figure 1, can also be used. Furthermore, this embodiment may include a heating element 99 (not shown).

[0104] The operation is basically the same as that of the embodiment in Figure 1, and there are the following differences in the realization of the individual elements.

[0105] The piston connecting element 94 that connects the piston 93 to the closing element 9 is formed by a hollow cylinder. The piston 93 surrounds the rear closing guide 98, which can be designed as a schematic cylinder, particularly a cylinder, and can also move linearly in the direction of movement. The piston connecting element 94 surrounds the bearing element 14 connected and fixed to the housing 16. The second volume 42 is placed between the rear closing guide, the piston 93, and the inside of the hollow cylinder or the piston connecting element 94.

[0106] The throttle between the first volume 41 and the second volume 42 is realized as a piston throttle 100 through one or more holes passing through the piston 93. However, the function of the piston throttle can also be achieved by the gap between the piston 93 and the rear closing guide 98.

[0107] The section 101 of the compressed air filling line 48 through which the control medium is supplied to the first volume 41 does not pass through the housing 16, but passes through the plug of the cylinder discharge valve 46 as a bore, for example, and can also be called the piston throttle of the cylinder discharge valve 46. Thereby, the control medium is supplied to the first volume 41 via the discharge valve volume 51.

[0108] Terminal position damping can be omitted. If terminal position damping is implemented in the embodiment of FIG. 5, this can be done as shown in FIG. 1 by a protruding piston closing element 95 that moves into the cylinder inlet / outlet 45, or by the cylinder inlet / outlet 45 being laterally guided within the first volume 41 and being closed by the piston 93 moving over the cylinder inlet / outlet 45 during the opening movement.

[0109] In an embodiment (not shown), two or more closing elements 9 are arranged parallel to each other to increase the total outlet area. They can be triggered synchronously with each other or each simultaneously to generate a pressure wave of higher energy than a single closing element 9. In this case, a plurality of closing elements are connected to a single pressure chamber 2 and actuated by a single pneumatic actuator. Such a parallel arrangement of the closing elements 9 can also be realized by a pressure wave generator which uses an explosion to generate pressure in the pressure chamber and / or to drive the closing elements.

[0110] The controller 20 is configured to execute the method steps described. For this purpose, the controller 20 is configured to control the compressed air valve 49, the working medium valve 10 and the cylinder discharge valve 46. The cylinder discharge valve 46 can be controlled by a discharge pilot valve 47.

[0111] Figures 3 and 4 show embodiments having a heater 80 for heating the working medium. According to the embodiment of Figure 3, the heater 80 is configured to heat the working medium when the working medium flows through the first filling line or the working medium filling line 12. The heated air does not experience any pressure increase. According to the embodiment of Figure 4, the heater 80 is configured to heat the working medium when the working medium flows through the circulation line 84. The circulation line 84 leads from the pressure chamber 2 through the heater 80 and back to the pressure chamber 2. The heating raises both the temperature and the pressure in the pressure chamber 2. A circulation blower 85 may be arranged to convey the working medium through the circulation line 84.

[0112] Each heater can have a heat exchanger 81 having a heat exchanger element 82 through which the working medium flows around. The heat exchanger element 82 can be heated by an electric heater 83.

[0113] In another embodiment not shown, the heat exchanger element 82 is arranged in the pressure chamber 2.

Claims

1. In an operating method of a pressure wave generator (1) having a pressure chamber (2), the pressure wave generator (1) is, a closing element (9) that closes the pressure chamber (2) with respect to the outlet (15) in the closed position and allows the working medium to flow from the pressure chamber (2) into the outlet (15) in the open position; a pneumatic actuator (4b) by which the closing element (9) can be moved from the closed position to the open position and also from the open position to the closed position by the pneumatic actuator (4b); comprising The method comprises filling the pressure chamber (2) with a gaseous working medium at a pressure exceeding 100 bar; moving the pneumatic actuator (4b) to move the closing element (9) in the opening direction to open the pressure chamber (2) with respect to the outlet (15); discharging the pressurized working medium from the pressure chamber (2) through the outlet (15) within a discharge time of less than 15 milliseconds; including repeating The pneumatic actuator (4b) is a first piston surface (91) acting on a gaseous control medium in a first volume (41), wherein the pressure in the first volume (41) generates an actuator force in a first direction on the first piston surface (91); a second piston surface (92) acting on a control medium in a second volume (42), wherein the pressure on the second piston surface (92) in the second volume (42) generates an actuator force in a second direction opposite to the first direction; comprising The closing element (9) can be brought from the closed position to the open position and also from the open position to the closed position by the pneumatic actuator (4b). The method of opening the pressure chamber (2) is discharging at least a part of the control medium from the first volume (41); Moving the pneumatic actuator (4b) in a second direction by making the pressure drop in the first volume (41) faster than the pressure drop in the second volume (42), thereby moving the closing element (9) in an opening direction, opening the pressure chamber (2) with respect to the outlet (15), and discharging the working medium from the pressure chamber (2) through the outlet (15). A method comprising the above steps. **Claim 2** The method according to claim 1, wherein the volume of the pressure chamber (2) exceeds 3 liters. **Claim 3** The method according to any one of claims 1 to 2, wherein the area of the narrowest point of the outlet (15) exceeds 20 square centimeters. **Claim 4** The method according to any one of claims 1 to 3, wherein the opening speed of the closing element (9) is greater than 10 m / s. **Claim 5** The method according to any one of claims 1 to 4, wherein the stroke of the closing element (9) during the opening and closing movement is between 30 millimeters and 150 millimeters. **Claim 6** The method according to any one of claims 1 to 5, wherein the filling of the pressure chamber (2) with the working medium is performed at a pressure exceeding 150 bar. **Claim 7** The method according to any one of claims 1 to 6, wherein the discharge time is less than 10 milliseconds. **Claim 8** The method according to any one of claims 1 to 7, wherein the working medium is one of air, nitrogen, or steam. **Claim 9** A step executed during the filling step or before the step of opening the pressure chamber (2) after the filling step, and a step of heating the working medium supplied to or placed in the pressure chamber (2). The method according to any one of claims 1 to 8, comprising the above steps. **Claim 10** In the method according to any one of claims 1 to 9, using a pneumatic actuator (4b), the pneumatic actuator (4b) includes a first piston surface (91) acting on the gaseous control medium in the first volume (41), wherein the pressure in the first volume (41) generates an actuator force in the first direction on the first piston surface (91). A second piston surface (92) acting on a control medium within a second volume (42), wherein a pressure on the second piston surface (92) within the second volume (42) creates an actuator force in a second direction opposite to the first direction; a second piston surface (92). comprising The closing element (9) can be brought from the closed position to the open position by the pneumatic actuator (4b), and can also be brought from the open position to the closed position. The method filling the first volume (41) with a pressurized gas control medium; By performing pressure compensation between the first volume (41) and the second volume (42) through a throttle, the pneumatic actuator (4b) is moved in the first direction due to the surface difference between the first piston surface (91) and the second piston surface (92), thereby moving the closing element (9) in the closing direction to close the pressure chamber (2). filling the pressure chamber (2) with a gaseous working medium; discharging at least a part of the control medium from the first volume (41), thereby opening the pressure chamber (2); By moving the pneumatic actuator (4b) in the second direction due to a faster pressure drop in the first volume (41) than in the second volume (42), the closing element (9) is moved in the opening direction to open the pressure chamber (2) with respect to the outlet (15), and discharging the control medium from the pressure chamber (2) through the outlet (15). A method that is repeatedly performed.

11. A pressure wave generator (1) for implementing the method according to any one of claims 1 to 10, comprising a pressure chamber (2), A closing element (9) that closes the pressure chamber (2) with respect to the outlet (15) in the closed position and allows the working medium to flow out from the pressure chamber (2) to the outlet (15) in the open position; A pneumatic actuator (4b) capable of bringing the closing element (9) from the closed position to the open position and from the open position to the closed position. A first piston surface (91) acting on a gaseous control medium within a first volume (41), wherein the pressure within the first volume (41) generates an actuator force in a first direction on the first piston surface (91), the first piston surface (91); A second piston surface (92) acting on a control medium within a second volume (42), wherein the pressure on the second piston surface (92) within the second volume (42) generates an actuator force in a second direction opposite to the first direction, the second piston surface (92); Comprising; The closing element (9) can be brought from the closed position to the open position by the pneumatic actuator (4b), and can also be brought from the open position to the closed position; The volume of the pressure chamber (2) exceeds 3 liters; The area of the narrowest point of the outlet (15) exceeds 20 square centimeters; A pressure wave generator (1) in which the stroke of the closing element (9) during the opening and closing movement is between 30 millimeters and 150 millimeters.

12. The pressure wave generator (1) according to claim 11, wherein the closing area of the closing opening that is respectively closed and opened by the closing element (9) is at least the same size as the area at the narrowest point of the outlet.

13. The pressure wave generator (1) according to claim 11 or 12, wherein the closing element (9) is hollow cylindrical and is arranged to open and close a closing opening corresponding to the cylindrical surface.

14. During the movement of opening the closing element (9) starting from the end position where the closing element (9) closes the closing opening, the closing element opens the closing opening only after covering a non-zero minimum distance. The pressure wave generator (1) according to any one of claims 12 to 13.

15. A pressure wave generator (1) for implementing the method according to claim 9, comprising a pressure chamber (2), wherein the pressure wave generator (1) is A closing element (9) that closes the pressure chamber (2) with respect to the outlet (15) in the closed position and allows the working medium to flow from the pressure chamber (2) into the outlet (15) in the open position; A pneumatic actuator (4b) that can bring the closing element (9) from the closed position to the open position and from the open position to the closed position; A heater (80) for heating the working medium supplied to the pressure chamber (2) or the working medium present in the pressure chamber (2); A pressure wave generator (1) comprising the same. **Claim 16** The pressure wave generator (1) according to any one of claims 11 to 15, comprising a controller (20), the controller (20) being configured to control the pressure wave generator (1) to execute the method according to any one of claims 1 to 11.

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