Pressure wave generator and method for operating a pressure wave generator

Abstract

A method for operating a pressure wave generator (1) having a pressure chamber (2), wherein the pressure wave generator (1) comprises: • a closing element (9) which closes the pressure chamber (2) relative to an outlet (14) in a closed position and enables a working medium to flow out of the pressure chamber (2) into the outlet (15) in an open position; • an actuator, by means of which the closing element (9) can be moved from a closed position to an open position and in particular also from an open position to a closed position; the method comprises the repeated execution of the following steps: • filling the pressure chamber (2) with a gaseous working medium at a pressure exceeding one hundred bar; • moving the actuator and thereby moving the closing element (9) in an opening direction, in order to open the pressure chamber (2) relative to the outlet (15) and discharge the pressurized working medium from the pressure chamber (2) through the outlet (15) within a discharge time period of less than fifteen milliseconds.

Description

Technical Field

[0001] The present invention relates to a device and a method for generating high-intensity pressure pulses. In particular, the present invention relates to a pressure wave generator according to the present disclosure and a method for operating the pressure wave generator. Background Art

[0002] In a pressure wave generator, as described in WO 2007 / 028264 and in particular in WO 2010 / 025574, the auxiliary explosion and the main explosion are ignited in chambers separated from each other. The auxiliary explosion is used to release the closure of the main explosion chamber directly or via other locking mechanisms, so that the subsequent main explosion does not act on the closure with full force and accordingly damage or destroy the closure. An explosion delay occurs between the auxiliary explosion and the main explosion. Such a delay is carried out, for example, by means of a delay line (in which the explosion is conducted from the auxiliary chamber to the main chamber), or by means of delayed ignition in the two chambers via separate ignition devices present in the chambers.

[0003] There is a need for a simplified pressure wave generator. Summary of the invention

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

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

[0006] At least one of these objects is achieved by a pressure wave generator and a method for operating a pressure wave generator according to the present disclosure.

[0007] The method is used to operate a pressure wave generator having a pressure chamber, wherein the pressure wave generator has:

[0008] a closure element which, in the closed position, closes the pressure chamber relative to the outlet and, in the open position, enables the working medium to flow out of the pressure chamber into the outlet;

[0009] an actuator, by means of which the closure element can be brought from a closed position into an open position and in particular also from an open position into a closed position;

[0010] The method comprises the following steps of repeatedly executing:

[0011] Filling the pressure chamber with a gaseous working medium at a pressure exceeding one hundred bar;

[0012] Moving the actuator and thereby the closure element in an opening direction in order to open the pressure chamber relative to the outlet and to discharge the pressurized working medium from the pressure chamber through the outlet within a discharge time period of less than fifteen milliseconds.

[0013] During the discharge time period, the pressure in the pressure chamber drops to ambient pressure.

[0014] In some embodiments, the volume of the pressure chamber is greater than three liters, in particular greater than four liters, in particular greater than five liters.

[0015] In some embodiments, the area at the narrowest point of the outlet is greater than twenty square centimeters, in particular greater than eighty square centimeters, in particular greater than one hundred and eighty square centimeters.

[0016] In the case of a circular outlet, the stated value of the area at the narrowest point, with respect to its diameter and rounding, corresponds to a diameter greater than five centimeters, in particular greater than ten centimeters, in particular greater than fifteen centimeters.

[0017] In some embodiments, the opening speed of the closure element is greater than ten meters per second, in particular greater than twenty meters per second, in particular at least thirty meters per second.

[0018] In some embodiments, the stroke of the closure element during the opening and closing movement is between thirty and one hundred and fifty millimeters, in particular between forty and one hundred millimeters, in particular between fifty and eighty millimeters.

[0019] In some embodiments, the pressure chamber is filled with a working medium at a pressure of more than one hundred and fifty bar, in particular more than two hundred bar.

[0020] In some embodiments, the discharge time period is less than ten milliseconds, particularly less than five milliseconds, particularly less than three milliseconds.

[0021] In some embodiments, the working medium is one of air, nitrogen and steam, in particular superheated steam or saturated steam.

[0022] In some embodiments, the method has the following steps performed after filling the pressure chamber and before opening the pressure chamber:

[0023] Heating of the working medium located in the pressure chamber, in particular when flowing through a circulation line connected to the pressure chamber, in particular wherein the working medium is conveyed through the circulation line by means of a circulation fan.

[0024] In some embodiments, the method has the following steps performed during filling of the pressure chamber:

[0025] Heating the working medium supplied to the pressure chamber, in particular when it flows through the working medium filling line.

[0026] In some embodiments, the working medium is heated to a temperature of 150 to 250 degrees Celsius, in particular 230 degrees Celsius, or to a temperature of 200 to 450 degrees Celsius, in particular 250 degrees Celsius. In contrast, the heating can be carried out, for example, with a temperature difference of more than 100 degrees Celsius, in particular more than 200 degrees Celsius, in particular more than 300 degrees Celsius, and sometimes also more than 400 degrees Celsius. The heating can be carried out, for example, using an electric heating element. The outflow velocity and therefore the impulse of the outflowing working medium increases with the square root of the temperature.

[0027] Another effect of heating the working medium is that it can prevent the working medium from cooling down too much when it leaves the pressure chamber. When it leaves, the working medium relaxes to the ambient pressure and can (depending on the situation and the type of working medium present) cool to a temperature below its liquefaction temperature. As a result, the jet propagates at maximum sonic speed after leaving, which limits the effectiveness of the device.

[0028] In some embodiments, a heater, in particular an electric heater, is provided for heating the working medium located in the pressure chamber.

[0029] In some embodiments, there is a heater arranged for heating the working medium in the working medium fill line.

[0030] In some embodiments, the heater is a heat exchanger, in particular having a heat exchanger element, in particular having an electrically heated heat exchanger element.

[0031] In some embodiments, the method is performed using a pneumatic actuator having:

[0032] a first piston surface acting on a gaseous control medium in the first volume, wherein a pressure in the first volume induces an actuator force in a first direction on the first piston surface;

[0033] a second piston surface acting on the control medium in the second volume, wherein the pressure in the second volume induces an actuator force on the second piston surface in a second direction opposite to the first direction;

[0034] wherein the closure element can be brought from a closed position into an open position and in particular also from an open position into a closed position by means of a pneumatic actuator;

[0035] The method comprises the following steps for opening the pressure chamber:

[0036] discharging at least a portion of the control medium from the first volume and thereby opening the pressure chamber, in particular by opening an inlet opening / outlet opening of the first volume;

[0037] Due to a faster pressure drop in the first volume than in the second volume, the actuator is moved in the second direction and thus the closure element in the opening direction in order to open the pressure chamber relative to the outlet and discharge the working medium from the pressure chamber through the outlet.

[0038] In some embodiments, the method is performed using a pneumatic actuator having:

[0039] a first piston surface acting on a gaseous control medium in the first volume, wherein a pressure in the first volume induces an actuator force in a first direction on the first piston surface;

[0040] A second piston surface acting on the control medium in the second volume, wherein the pressure in the second volume induces an actuator force on the second piston surface in a second direction opposite to the first direction.

[0041] In this case, the closure element can be moved from the closed position into the open position and in particular also from the open position into the closed position by means of a pneumatic actuator.

[0042] The method has the following steps of repeated execution:

[0043] a) filling the first volume with a pressurized gaseous control medium, in particular by means of a filling valve, for example a compressed air valve;

[0044] b) performing pressure equalization between the first volume and the second volume via the throttle element, thereby moving the actuator in a first direction due to the area difference between the first piston surface and the second piston surface, thereby moving the closing element in a closing direction and closing the pressure chamber;

[0045] c) filling the pressure chamber with a gaseous working medium;

[0046] d) discharging at least a portion of the control medium from the first volume and thereby opening the pressure chamber, in particular by opening an inlet opening / outlet opening of the first volume;

[0047] e) Due to a faster pressure drop in the first volume than in the second volume, the actuator is moved in the second direction and thus the closing element in the opening direction, in order to open the pressure chamber relative to the outlet and discharge the working medium from the pressure chamber through the outlet.

[0048] Steps a), b) and c) can be performed simultaneously or overlapped in time. Step d) is usually performed after steps a), b) and c). In step d), the opening of the pressure chamber triggered by opening the inlet opening / outlet opening directly transitions to step e).

[0049] In some embodiments, the time period between triggering the opening movement of the closure element (eg by actuating the outlet solenoid valve) and maximum opening of the closure element lies in the range of 20 to 120 milliseconds, in particular between 40 and 60 milliseconds.

[0050] In some embodiments, the time period for opening the closure element is less than ten milliseconds, in particular less than five milliseconds, in particular less than three milliseconds. This time period can be substantially equal to the discharge time period.

[0051] The pressure wave generator according to the first aspect is used to perform the above method. The pressure wave generator has a pressure chamber, and

[0052] a closure element which, in the closed position, closes the pressure chamber relative to the outlet and, in the open position, enables the working medium to flow out of the pressure chamber into the outlet;

[0053] an actuator, by means of which the closure element can be brought from a closed position into an open position and from an open position into a closed position;

[0054] wherein the volume of the pressure chamber is greater than three liters, in particular greater than four liters, in particular greater than five liters;

[0055] wherein the volume of the pressure chamber is in particular less than fifteen liters;

[0056] wherein the area at the narrowest part of the outlet exceeds 20 square centimeters, in particular exceeds 80 square centimeters, in particular exceeds 180 square centimeters;

[0057] In this case, the stroke of the closure element during the opening and closing movement is between thirty and one hundred and fifty millimeters, in particular between forty and one hundred millimeters, in particular between fifty and eighty millimeters.

[0058] This allows the generation of an outgoing jet by means of a pressure wave generator, which, after free expansion of the jet in free space, generates there the greatest possible maximum pressure or the greatest possible force. To this end, the mass flow generated by means of the pressure wave generator is made as great as possible. The mass flow is proportional to the density and the exit velocity of the working medium and to the area of ​​the exit opening. Thus, starting from the preset filling pressure of the gaseous working medium in the pressure chamber, a combination of parameters can be determined within the limits defined above, which combination generates the maximum pressure of the outgoing jet.

[0059] In some embodiments, the closed area of ​​the closed opening closed and opened by the closing element, respectively, is at least as large as the area at the narrowest point of the outlet, in particular at least ten percent larger than the area at the narrowest point of the outlet.

[0060] This is different from conventional valves in which the narrowest point is formed by the valve. In 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 occurs after the narrowest point. This leads to a compression shock in the outlet, which impedes the performance of the device. This is prevented by carrying out the expansion of the exiting jet outside the outlet.

[0061] In some embodiments, the closure element is hollow cylindrical and is arranged to close or open a closure opening corresponding to a surface of the cylinder.

[0062] The hollow cylindrical design allows the mass of the closing element to be reduced. In addition, the annular surface of the piston surrounding the hollow cylindrical recess determines a recoil force, with which the exiting gas drives the piston back. In some embodiments, the area of ​​the hollow cylindrical recess, viewed in cross section, is greater than 25 percent, in particular greater than 50 percent, of the area of ​​the closing element. The cylindrical closing surface allows the area of ​​the closing surface to vary greatly with the closing movement.

[0063] In some embodiments, the sum of the areas at the closure element where the pressurized working medium exerts a force on the closure element in the closing direction is less than ten percent of the cross-sectional area of ​​the outlet at the location where the outlet is closed by the closure element.

[0064] In an embodiment, the area of ​​the inlet opening / outlet opening of the first volume is between 200 square millimeters and 500 square millimeters, or a maximum of 1,500 square millimeters. For a circular cross section of the opening, this corresponds to a rounding diameter of between 16 millimeters and 25 millimeters, or a maximum of 44 millimeters. The first volume can thus be emptied quickly enough and a correspondingly fast opening movement can therefore be performed again. It has been shown that this diameter is generally independent of the first piston area (i.e. the area of ​​the piston in the first volume).

[0065] In some embodiments, when the closing element performs the opening movement, starting from the end position where the closing element closes the closed opening, the closing element opens the closed opening only after a minimum distance has passed. The distance is non-zero. In particular, the distance is greater than five millimeters, or greater than eight millimeters.

[0066] The pressure wave generator according to the second aspect is used to perform the above method. The pressure wave generator has a pressure chamber, and

[0067] a closure element which, in the closed position, closes the pressure chamber relative to the outlet and, in the open position, enables the working medium to flow out of the pressure chamber into the outlet;

[0068] an actuator, by means of which the closure element can be brought from a closed position into an open position and from an open position into a closed position;

[0069] • A heater, which is arranged to heat a working medium supplied to the pressure chamber or present in the pressure chamber, in particular wherein the heater is an electric heater.

[0070] A pneumatic actuator, in particular for use in a pressure wave generator, comprising:

[0071] a first piston surface acting on a gaseous control medium in the first volume, wherein a pressure in the first volume induces an actuator force in a first direction on the first piston surface;

[0072] a second piston surface acting on the control medium in the second volume, wherein the pressure in the second volume induces an actuator force on the second piston surface in a second direction opposite to the first direction;

[0073] a restriction between the first volume and the second volume;

[0074] an inlet opening / outlet opening of the first volume for introducing a control medium into the first volume or for discharging the control medium from the first volume;

[0075] Wherein, the first piston surface is larger than the second piston surface.

[0076] In some embodiments, the pneumatic actuator has an end position damping, in particular by closing the inlet opening / outlet opening. Thus, the inlet opening / outlet opening is closed relative to the first volume.

[0077] In some embodiments, the piston closing element is arranged for closing the inlet opening / outlet opening. Thus, end position damping can be achieved in a simple manner by elements of the piston itself.

[0078] In the method for operating a pneumatic actuator, the following steps are performed:

[0079] filling the first volume with a pressurized gaseous control medium, in particular by means of a filling valve, for example a compressed air valve;

[0080] A pressure balance is performed between the first volume and the second volume by the throttle element, and thereby the actuator is moved in the first direction due to the difference in area between the first piston surface and the second piston surface;

[0081] Discharging at least a portion of the control medium from the first volume, in particular by opening the inlet opening / outlet opening;

[0082] The actuator is moved in the second direction by a faster pressure drop in the first volume than in the second volume.

[0083] The reciprocating motion of the actuator can thus be achieved with simple means (only a filling valve and an inlet opening / outlet opening). This is on the one hand a result of the area difference between the piston surfaces and on the other hand a result of the throttle between the two volumes.

[0084] The inlet opening / outlet opening can be designed to be relatively large in order to bring about a rapid pressure drop in the first volume.

[0085] In some embodiments, the piston closure element is also arranged to isolate the control medium filling line relative to the first volume.Thereby, high pressure surges in the filling line can be avoided.

[0086] In some embodiments, the two volumes are realized as part of a common working space of the cylinder, in which a single piston is arranged, on which the two piston surfaces are formed.

[0087] Therefore, the sealing of the piston relative to the (now common) cylinder is unimportant. There can even be a gap between the piston and the cylinder. This gap has the function of a throttle between the two volumes. That is, pressure balance occurs via this gap. The structure can thus be further simplified. In this embodiment, the throttle is formed by the gap between the cylinder and the piston. The other common seals of the piston are omitted here.

[0088] In another embodiment, the two volumes and the piston surfaces are located on separate pistons in separate cylinders, and the two separate pistons are mechanically coupled and their movements are also coupled here.

[0089] In some embodiments, the first piston surface and the piston closing element for closing the inlet opening / outlet opening are formed on the same piston. Thus, a particularly simple and reliable structure can be achieved.

[0090] In some embodiments, the pneumatic actuator has a cylinder discharge valve for rapidly discharging the control medium from the first volume by opening the inlet opening / outlet opening. The cylinder discharge valve has a piston surface, at which a force for closing the cylinder discharge valve is generated when loaded with the control medium, and a valve surface, at which a force in the opening direction of the cylinder discharge valve is generated when loaded with the control medium, wherein the valve surface is smaller than the piston surface. Thus, by loading both surfaces with the same pressure, the cylinder discharge valve can be brought and maintained in the closed position.

[0091] In some embodiments, the pneumatic actuator has a discharge pilot valve for discharging a control medium from the discharge valve volume, wherein the control medium acts on the piston surface. This can produce a momentary, temporary pressure imbalance on the two surfaces, thereby opening the cylinder discharge valve.

[0092] In some embodiments, the control medium filling line is arranged for filling the outlet valve volume and the first volume with control medium at the same pressure. Thus, on the one hand, the same pressure can be achieved in both volumes, and on the other hand (by using the filling line between the two volumes as a throttle) a temporary imbalance can be achieved.

[0093] The pressure in the control medium is, for example, between 50 and 140 bar, in particular between 80 and 100 bar.

[0094] In some embodiments, the section of the control medium filling line (through which the first volume is supplied with control medium) extends through the cylinder outlet valve, especially the closing body of the valve. For example, the section is a channel in the closing body, which also allows a small amount of flow through the valve in the closed position of the valve.

[0095] In some embodiments, the section of the control medium filling line, via which the first volume is supplied with control medium, extends through the housing of the pressure wave generator.

[0096] In some embodiments, the linear guide of the piston is formed by making the piston surround the closed guide at the rear and can move linearly along the closed guide at the rear in the direction of movement, and a hollow cylindrical piston connecting element extending away from the piston in the direction of movement surrounds a support element, which is fixed to the closed guide at the rear. Here, the second volume is formed between the piston, the inner side of the piston connecting element, the support element and the closed guide at the rear. Usually, the closed guide at the rear is fixedly connected to the housing.

[0097] Thus, 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, this is the case with the pressure wave generator described here with a hollow cylindrical closing element.

[0098] Further preferred embodiments are disclosed. Features relating to the method can hereby be combined expediently with features relating to the device, and vice versa.

[0099] In particular, the pressure wave generator can have a controller which is configured to actuate the pressure wave generator in order to carry out the method according to the disclosure. The actuation is achieved by actuating at least a valve of the pressure wave generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] The subject matter of the present invention is described in more detail below based on the preferred embodiments shown in the accompanying drawings. In which:

[0101] Figure 1 A longitudinal section through a pressure wave generator is shown;

[0102] Figure 2shows a longitudinal section through another embodiment; and

[0103] Figure 3-4 An embodiment is shown which has a heater for heating the working medium.

[0104] In principle, identical parts are provided with the same reference symbols in the figures. DETAILED DESCRIPTION

[0105] Figure 1 and Figure 2 In each case a pressure wave generator 1 is shown with a pressure chamber 2 . A closing element 9 is arranged opposite the outlet 15 for closing the pressure chamber 2 .

[0106] The closure element 9 is guided on a bearing element 14 which allows a linear opening and closing movement of the closure element 9. Figure 1 In the embodiment of the invention, the closing element 9 is hollow cylindrical and has a piston which is guided through a support element 14 which is fixedly connected to the housing 16. Figure 2 In the embodiment of the present invention, the closing element 9 is hollow cylindrical and surrounds the support element 14 which is fixedly connected to the housing 16. The movement direction indicated by the double arrow is usually equivalent to the longitudinal direction of the pressure wave generator 1 and also to the outflow direction along which the working medium flows out of the outlet 15. Figure 1 and Figure 2 The closure element 9 is shown in the closed position, ie the pressure chamber 2 is closed with respect to the outlet 15 .

[0107] The outlet 15 serves for the directed discharge or discharge of the working medium, thereby generating a pressure wave.

[0108] In the open position, the closure element 9 releases the closure surface of the closure opening. In the closed position, the closure opening is closed by the closure element 9. Here, the closure surface is a cylindrical surface. The pressure chamber 2 is annular. The pressure chamber 2 surrounds the closure element 9. The closure opening is guided inwards from the pressure chamber 2 in a radial direction (relative to the annular pressure chamber 2). The working medium leaving through the closure opening flows inwards in a radial direction and then flows in an axial direction (again relative to the annular pressure chamber 2) through the outlet 15.

[0109] In the closed state, the closure element 9 rests against the valve seat of the housing 16. The valve seat can be designed with a collar, which causes the closure opening to open and the working medium to flow out only after a certain distance of the closure element 9 has been traveled when the closure element is moved from the end position of the closed position in the opening direction. This distance is plotted as the collar width 77. As a result, the movement of the closure element 9 can be accelerated before the closure opening opens, which in turn enables the closure opening to open quickly enough to allow the working medium to flow out suddenly.

[0110] The size of the closed area is greater than the area of ​​the outlet or the outlet area, i.e. the cross-sectional area of ​​the outlet transitioning into the free space. In particular, the outlet 15 corresponds to the narrowest point along the path of the working medium out of the pressure chamber 2. This results in the outflowing working medium having the highest speed in the outlet 15 or shortly thereafter. In particular, the outflowing working medium thus reaches the speed of sound shortly after the narrowest point, i.e. after the outlet 15. This is advantageous for the operation of the device.

[0111] A first filling line or working medium filling line 12 is arranged for filling the pressure chamber 2 with working medium. It is supplied via a working medium valve 10 .

[0112] In a method for operating the device

[0113] The pressure chamber 2 is closed relative to the outlet 15 by means of the closing element 9;

[0114] Filling the pressure chamber 2 with a working medium under high pressure, ie at a pressure exceeding one hundred bar, in particular exceeding one hundred and fifty bar, in particular exceeding two hundred bar;

[0115] The pressure chamber 2 is suddenly opened so that the energy stored in the working medium is converted into kinetic energy in the shortest possible time period. The shorter this time period, the higher the speed and momentum of the outflowing working medium, and therefore the better the effect of the pressure wave.

[0116] In some implementations, the following parameters are implemented:

[0117] Pressure: 100 bar to 300 bar

[0118] Volume: 3 liters to 15 liters

[0119] Exit area: 50cm 2 Up to 320cm 2 (=Diameter about 80-200mm)

[0120] Opening speed: 15m / s to 40m / s

[0121] Stroke: 50mm to 100mm.

[0122] In some implementations, the following parameters are implemented:

[0123] Pressure: greater than 120 bar

[0124] Volume: 4 liters

[0125] Exit area: 80cm 2 (corresponding to a diameter of about 100 mm)

[0126] Opening speed: greater than 15m / s

[0127] Stroke: 60mm.

[0128] In some implementations, the following parameters are implemented:

[0129] Pressure: 250 bar to 300 bar, especially 280 bar

[0130] Volume: 8 to 12 liters, especially 10 liters

[0131] Exit area: 150cm 2 Up to 210cm 2 , especially 180cm 2 (corresponding to a diameter of about 150mm)

[0132] Opening speed: greater than 25m / s

[0133] Stroke: 60mm to 90mm, especially 75mm.

[0134] In some implementations, the following parameters are implemented:

[0135] Pressure: 250 bar to 300 bar, especially 280 bar

[0136] Volume: 4 to 6 liters, especially 5 liters Outlet area: 60 cm 2 Up to 80cm 2 , especially 70cm 2 (corresponding to a diameter of about 95mm)

[0137] Opening speed: greater than 20m / s

[0138] Stroke: 50mm to 70mm, especially 60mm.

[0139] In all embodiments, the working medium can be heated to a temperature of 150 degrees Celsius to 250 degrees Celsius, in particular 230 degrees Celsius, or to a temperature of 200 degrees Celsius to 450 degrees Celsius, in particular 250 degrees Celsius.

[0140] The opening movement of the closing element 9 is caused by an active gas spring or pneumatic actuator 4b. The active gas spring or pneumatic actuator has a cylindrical working space 43, in which a piston 93 moves, the movement of which is coupled to the movement of the closing element 9, in particular by connecting them firmly to each other, in particular in one piece. Figure 1 and Figure 2 In the embodiment of , the coupling is performed via a piston connecting element 94. Figure 1 This is the piston rod, Figure 2 This is a hollow cylinder.

[0141] The piston 93 divides the working space 43 into a first volume 41 and a second volume 42. There is no seal between the cylinder inner wall 44 of the working space 43 and the piston 93. In particular, there may also be a smaller gap, which is referred to as a piston gap 96 below. This piston gap allows gas exchange between the two volumes and is particularly used as a throttle at this. In other embodiments, a separate pipeline can be arranged between the first volume 41 and the second volume 42, and a throttle can be provided, which allows gas exchange in addition to or alternatively to the piston gap 96. Such a throttle can also be implemented as a piston throttle 100 by passing through one or more holes of the piston 93, which therefore also allows gas exchange between the two volumes.

[0142] The gas pressure of the control medium in the first volume 41 brings about a force which is opposed to the direction of the opening movement of the closure element 9 , wherein the surface which is effective here is the first piston surface 91 .

[0143] The gas pressure of the control medium in the second volume 42 brings about a force in the direction of the opening movement of the closure element 9 , wherein the effective surface here is the second piston surface 92 .

[0144] In this case, the second piston surface 92 is smaller than the first piston surface 91 , for example, at least 5 percent, 10 percent or 20 percent smaller.

[0145] The piston 93 has a piston closing element 95 which closes the cylinder inlet / cylinder outlet 45 or the inlet opening / outlet opening of the first volume 41 during the opening movement. The cylinder inlet / cylinder outlet 45 is shown here concentrically with the working space 43, but can alternatively also be arranged laterally. By closing the cylinder inlet / cylinder outlet 45, a brake or end position damping of the opening movement is brought about. At the same time, the compressed air valve 49 is also protected from pressure shocks via the compressed air filling line 48.

[0146] The cylinder inlet / cylinder outlet 45 can be opened by a cylinder discharge valve 46. The control medium flows out, for example, via a discharge line or ventilation line 102. The cylinder discharge valve 46 can have a relatively large valve cross section compared to the filling line. Thus, a sudden pressure reduction in the first volume 41 can be achieved. The cylinder discharge valve 46 is kept closed by the pressure in the compressed air filling line 48. This pressure can be reduced by opening the discharge pilot valve 47. By opening the discharge pilot valve, an opening movement of the closing element is triggered.

[0147] The cylinder discharge valve 46 is, for example, a central valve with a movable shut-off body. The shut-off body has a piston surface 52, at which the shut-off body is loaded with compressed air from the compressed air filling line 48 in the discharge valve volume 51. The valve surface 53 loaded with pressure in the cylinder inlet / cylinder outlet 45 is smaller than the piston surface 52. The forces on the piston surface 52 and the valve surface 53 are opposite to each other. When the discharge pilot valve 47 is closed, the gas pressure at both surfaces is the same, and the force on the piston surface 52 is greater than the force on the valve surface 53, thereby keeping the shut-off body or the cylinder discharge valve 46 in the closed position.

[0148] The compressed air filling line 48 also supplies the first volume 41 via a section 101 of the compressed air filling line 48 , which in turn supplies via a compressed air valve 49 .

[0149] The ventilation line 97 brings about a pressure balance between the ambient air and the intermediate cylinder.The intermediate cylinder is located between the rear end of the closing element 9 and the active gas spring or pneumatic actuator 4b.

[0150] exist Figure 1 In a variant of the embodiment of , the working space 43 and the piston 93 are realized compactly. However, the same functional mode can also be realized with a separate first and second volume and with separate pistons with different piston areas. In this case, a line with a throttle is arranged between the two volumes, and the movement of the two pistons is mechanically coupled. This means that a linear movement of one of the two pistons always also causes a linear movement of the other piston.

[0151] exist Figure 1 and Figure 2 In the embodiment of the present invention, the piston stroke can be between 20 mm and 150 mm, in particular between 30 mm and 80 mm, for example. The diameter of the piston can be between 20 mm and 200 mm, in particular between 40 mm and 120 mm, for example.

[0152] In some embodiments, a heating element 99 is present. Thus, the working medium under pressure in the pressure chamber 2 can be heated. As a result, the energy of the generated pressure wave can be increased.

[0153] Figure 1 and Figure 2 A pneumatic actuator 4 b is shown in combination with a pressure wave generator 1 .

[0154] During operation of this variant, the following method steps can be performed:

[0155] The compressed air valve 49 is opened with the discharge pilot valve 47 closed. This has the following effect: the pressure in the compressed air filling line 48 (e.g. 70 bar) causes the cylinder discharge valve 46 to close. The first volume 41 is loaded with compressed air via the compressed air filling line 48. The second volume 42 is also loaded via the piston gap 96, wherein the same pressure prevails in both volumes over time. Since the first piston surface 91 is larger than the second piston surface 92, the piston 93 and thus the closure element 9 are moved into the closed position (opposite to the direction of the opening movement).

[0156] • Close the compressed air valve 49. The closure element 9 remains in the closed position.

[0157] The working medium valve 10 is opened and the pressure chamber 2 is filled thereby.

[0158] The opening movement is triggered by opening the cylinder outlet valve 46, which can be achieved in particular by opening the discharge pilot valve 47 and reducing the pressure in the compressed air filling line 48. By opening the cylinder outlet valve 46, the pressure in the first volume 41 drops. The pressure in the second volume 42 also drops, but more slowly than in the first volume 41 due to the throttling effect of the piston gap 96. As a result, the force on the second piston surface 92 becomes greater than the force on the first piston surface 91 again. This causes a movement of the piston 93 and thus an opening movement of the closure element 9.

[0159] Before the piston 93 or the closure element 9 reaches the stop, the piston closure element 95 closes the cylinder inlet / cylinder outlet 45. The air remaining in the (now smaller) first volume 41 is compressed and brakes the movement of the piston 93 and the closure element 9. The compressed air valve 49 is prevented from being stressed by pressure peaks.

[0160] The working medium flows out from the opening released by the closure element 9 .

[0161] The cylinder outlet valve 46 is closed, in particular by closing the discharge pilot valve 47. This can be achieved in that the piston surface, through which the compressed air in the compressed air filling line 48 presses the cylinder outlet valve 46 or its shut-off body into the closed position, is greater than the surface on which the compressed air acts in the opposite direction on the cylinder outlet valve 46 or its shut-off body. After the cylinder outlet valve 46 is closed, the pressure in the first volume 41 can still be high enough (e.g. 20 bar) to also move the piston 93 back after pressure equalization with the second volume 42 and thus bring the closure element 9 into the closed position.

[0162] The method can then be restarted by opening the compressed air valve 49 .

[0163] When using the pneumatic actuator 4b as described above, the movement of the closing element in the opening direction is achieved by the movement of the pneumatic actuator in the second direction. The movement of the closing element in the closing direction is achieved by the movement of the pneumatic actuator in the first direction.

[0164] Figure 2 shows a method having Figure 1 Different alternative embodiments of the pneumatic actuator 4b may be: Figure 2 The entire pneumatic actuator shown in FIG. 1 or only individual components, such as

[0165] Piston throttle 100; and / or

[0166] A closing element 9 having a hollow cylinder instead of a piston rod as the piston connecting element 94; and / or

[0167] Cylinder outlet valve 46 with section 101 of compressed air filling line

[0168] According to Figure 1 The pressure wave generator 1 is combined. In addition, this embodiment can also have a heating element 99 (not shown).

[0169] Functional mode and Figure 1 The implementation methods are basically the same, with the following differences in the implementation of individual elements:

[0170] The piston connecting element 94 connecting the piston 93 to the closure element 9 is formed by a hollow cylinder. The piston 93 surrounds the rear closure guide 98, which can be configured as a general cylinder, in particular a cylinder, and can move linearly along the same direction of movement. The piston connecting element 94 surrounds the support element 14 fixedly connected to the housing 16. The second volume 42 is located between the rear closure guide, the piston 93 and the inner side of the hollow cylinder or the piston connecting element 94.

[0171] The throttle between the first volume 41 and the second volume 42 is realized as a piston throttle 100 by one or more holes through the piston 93. In addition or alternatively, however, the function of the piston throttle can also be assumed by the gap between the piston 93 and the rear closure guide 98.

[0172] The section 101 of the compressed air filling line 48, via which the first volume 41 is supplied with the control medium, does not extend through the housing 16, but rather, for example, as a bore through a shut-off body of the cylinder outlet valve 46 and can also be referred to as a piston throttle of the cylinder outlet valve 46. The first volume 41 is therefore supplied with the control medium via the outlet valve volume 51.

[0173] The end position damping can be omitted. Figure 2In the embodiment of the invention, end position damping is achieved, which can be done as follows Figure 1 This can be achieved by a protruding piston closing element 95 that is moved into the cylinder inlet / cylinder outlet 45, or by introducing the cylinder inlet / cylinder outlet 45 laterally into the first volume 41 and closing it by pushing the piston 93 over the cylinder inlet / outlet 45 during the opening movement.

[0174] In some embodiments (not shown), two or three or more closure elements 9 are arranged in parallel with each other to increase the overall outlet area. The closure elements can be triggered synchronously or simultaneously with each other to generate a pressure wave with higher energy than using a single closure element 9. Here, a plurality of closure elements are connected to a single pressure chamber 2 and are operated by a single pneumatic actuator. Such a parallel arrangement of closure elements 9 can also be achieved using a pressure wave generator that uses an explosion to generate pressure in the pressure chamber and / or drive the closure elements.

[0175] The control unit 20 is configured to carry out the described method steps. To this end, the control unit 20 is configured to control the compressed air valve 49 , the working medium valve 10 and the cylinder outlet valve 46 . The cylinder outlet valve 46 can be controlled by means of an outlet pilot valve 47 .

[0176] Figure 3 and Figure 4 An embodiment is shown with a heater 80 for heating the working medium. Figure 3 In the embodiment of the invention, the heater 80 is arranged to heat the working medium as it flows through the first filling line or the working medium filling line 12. The heated air does not experience a pressure increase here. Figure 4 In an embodiment of the present invention, the heater 80 is arranged to heat the working medium as it 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. By heating, the temperature and pressure in the pressure chamber 2 are increased. A circulation fan 85 can be arranged to convey the working medium through the circulation line 84.

[0177] The heaters can each have a heat exchanger 81 with a heat exchanger element 82 around which the working medium flows. The heat exchanger element 82 can be heated by an electric heater 83 .

[0178] In another embodiment (not shown), the heat exchanger element 82 is arranged in the pressure chamber 2 .

Claims

1. A method for operating a pressure wave generator (1) having a pressure chamber (2), wherein: The pressure wave generator (1) comprises: a closure element (9) which, in a closed position, closes the pressure chamber (2) relative to the outlet (15) and, in an open position, enables the working medium to flow out of the pressure chamber (2) into the outlet (15); a pneumatic actuator, by means of which the closure element (9) can be brought from the closed position into the open position and vice versa; Wherein, the pneumatic actuator (4b) has: a first piston surface (91) acting on a gaseous control medium in a first volume (41), wherein a pressure in the first volume (41) induces an actuator force in a first direction on the first piston surface (91); a second piston surface (92) acting on the control medium in a second volume (42), wherein the pressure in the second volume (42) causes an actuator force on the second piston surface (92) in a second direction opposite to the first direction; The method comprises the following steps of repeatedly executing: Filling the pressure chamber (2) with a gaseous working medium at a pressure exceeding one hundred bar; moving the actuator and thereby the closure element (9) in an opening direction in order to open the pressure chamber (2) relative to the outlet (15) and to discharge the working medium under pressure from the pressure chamber (2) through the outlet (15) within a discharge time period of less than fifteen milliseconds; The method comprises the following steps for opening the pressure chamber (2): by opening an inlet opening / outlet opening of the first volume (41), discharging at least a portion of the control medium from the first volume (41) and thereby opening the pressure chamber (2); Due to a faster pressure drop in the first volume (41) than in the second volume (42), the actuator is moved in the second direction and thereby the closing element (9) is moved in the opening direction, in order to open the pressure chamber (2) relative to the outlet (15) and to discharge the working medium from the pressure chamber (2) through the outlet (15).

2. The method according to claim 1, wherein: The volume of the pressure chamber (2) is greater than three liters.

3. The method according to claim 1, wherein: The volume of the pressure chamber (2) is greater than four liters.

4. The method according to claim 1, wherein: The volume of the pressure chamber (2) is greater than five liters.

5. The method according to claim 1, wherein: The area at the narrowest part of the outlet (15) is greater than twenty square centimeters.

6. The method according to claim 1, wherein: The area at the narrowest point of the outlet (15) is greater than eighty square centimeters.

7. The method according to claim 1, wherein: The area at the narrowest part of the outlet (15) is greater than one hundred and eighty square centimeters.

8. The method according to claim 1, wherein: The opening speed of the closure element (9) is greater than ten meters per second.

9. The method according to claim 1, wherein: The opening speed of the closure element (9) is greater than twenty meters per second.

10. The method according to claim 1, wherein: The opening speed of the closure element (9) is at least thirty meters per second.

11. The method according to claim 1, wherein: The stroke of the closure element (9) during the opening and closing movement is between thirty and one hundred and fifty millimeters.

12. The method according to claim 1, wherein: The stroke of the closure element (9) during the opening and closing movement is between 40 and 100 millimeters.

13. The method according to claim 1, wherein: The stroke of the closure element (9) during the opening and closing movement is between fifty and eighty millimeters.

14. The method according to claim 1, wherein: The pressure chamber (2) is filled with the working medium at a pressure greater than one hundred and fifty bar.

15. The method according to claim 1, wherein: The pressure chamber (2) is filled with the working medium at a pressure greater than two hundred bar.

16. The method according to claim 1, wherein: The discharge time period is less than ten milliseconds.

17. The method according to claim 1, wherein: The expulsion time period is less than five milliseconds.

18. The method according to claim 1, wherein: The expulsion time period is less than three milliseconds.

19. The method according to claim 1, wherein: The working medium is one of air, nitrogen and steam.

20. The method according to claim 1, wherein: The working medium is superheated steam or saturated steam.

21. The method according to claim 1, comprising the steps of: performing during filling or after filling and before opening the pressure chamber: Heating the working medium supplied to the pressure chamber or located in the pressure chamber.

22. The method according to claim 21, wherein: The working medium supplied to the pressure chamber or located in the pressure chamber is heated to 200 degrees Celsius to 450 degrees Celsius.

23. The method according to claim 21, wherein: The working medium supplied to the pressure chamber or located in the pressure chamber is heated to 250 degrees Celsius.

24. The method according to any one of claims 21 to 23, wherein: The heating is performed using electrical energy.

25. The method according to claim 1, using the pneumatic actuator (4b), in, The method comprises the following steps of repeatedly executing: Filling the first volume (41) with a gaseous control medium under pressure by means of a filling valve; The throttle element balances the pressure between the first volume (41) and the second volume (42), thereby causing the actuator to move in the first direction due to the difference in area between the first piston surface (91) and the second piston surface (92), thereby causing the closing element (9) to move in the closing direction and close the pressure chamber (2); Filling the pressure chamber (2) with a gaseous working medium.

26. The method according to claim 25, wherein: The filling valve is a compressed air valve (49).

27. A pressure wave generator (1) for performing the method according to claim 1, comprising a pressure chamber (2), and a closing element (9) which, in a closed position, closes the pressure chamber (2) relative to the outlet (15) and, in an open position, enables the working medium to flow out of the pressure chamber (2) into the outlet (15); a pneumatic actuator, by means of which the closure element (9) can be brought from the closed position into the open position and from the open position into the closed position; ·in, The volume of the pressure chamber (2) is greater than three liters; wherein the area at the narrowest part of the outlet (15) is greater than twenty square centimeters; wherein the travel of the closure element (9) during the opening and closing movement is between thirty and one hundred and fifty millimeters; Wherein, the pneumatic actuator (4b) has: a first piston surface (91) acting on a gaseous control medium in a first volume (41), wherein a pressure in the first volume (41) induces an actuator force in a first direction on the first piston surface (91); A second piston surface (92) acting on the control medium in a second volume (42), wherein the pressure in the second volume (42) induces an actuator force on the second piston surface (92) in a second direction opposite to the first direction.

28. The pressure wave generator (1) according to claim 27, wherein: The volume of the pressure chamber (2) is greater than four liters.

29. The pressure wave generator (1) according to claim 27, wherein: The volume of the pressure chamber (2) is greater than five liters.

30. The pressure wave generator (1) according to claim 27, wherein: The area at the narrowest point of the outlet (15) is greater than eighty square centimeters.

31. The pressure wave generator (1) according to claim 27, wherein: The area at the narrowest part of the outlet (15) is greater than one hundred and eighty square centimeters.

32. The pressure wave generator (1) according to claim 27, wherein: The stroke of the closure element (9) during the opening and closing movement is between 40 and 100 millimeters.

33. The pressure wave generator (1) according to claim 27, wherein: The stroke of the closure element (9) during the opening and closing movement is between fifty and eighty millimeters.

34. The pressure wave generator (1) according to claim 27, wherein: The closed area of ​​the closed opening which is respectively closed and opened by the closing element (9) is at least as large as the area at the narrowest point of the outlet.

35. The pressure wave generator (1) according to claim 27, wherein: The closed area of ​​the closed opening respectively closed and opened by the closing element (9) is at least ten percent larger than the area at the narrowest point of the outlet.

36. The pressure wave generator (1) according to claim 27, wherein: The closing element (9) is hollow cylindrical and is arranged to close or open a closed opening corresponding to the surface of the cylinder.

37. The pressure wave generator (1) according to claim 27, wherein: When the closing element (9) performs an opening movement, starting from the end position where the closing element (9) closes the closing opening, the closing element opens the closing opening only after traveling a minimum distance, the distance being non-zero.

38. The pressure wave generator (1) according to claim 37, wherein: The distance is greater than five millimeters, or greater than eight millimeters.

39. The pressure wave generator (1) according to any one of claims 27 to 38, wherein: The pressure wave generator (1) has a controller (20) which is configured to operate the pressure wave generator (1).

40. A pressure wave generator (1) for performing the method according to claim 21, comprising a pressure chamber (2), and a closure element (9) which, in a closed position, closes the pressure chamber (2) relative to the outlet (15) and, in an open position, enables the working medium to flow out of the pressure chamber (2) into the outlet (15); a pneumatic actuator, by means of which the closure element (9) can be brought from the closed position to the open position and from the open position to the closed position; a heater (80) arranged to heat a working medium supplied to the pressure chamber (2) or present in the pressure chamber (2); in, The pneumatic actuator (4b) comprises: a first piston surface (91) acting on a gaseous control medium in a first volume (41), wherein a pressure in the first volume (41) induces an actuator force in a first direction on the first piston surface (91); A second piston surface (92) acting on the control medium in a second volume (42), wherein the pressure in the second volume (42) induces an actuator force on the second piston surface (92) in a second direction opposite to the first direction.

41. The pressure wave generator (1) according to claim 40, wherein: The heater (80) is an electric heater.

42. A pressure wave generator (1) according to claim 40 or 41, wherein: The pressure wave generator (1) has a controller (20) which is configured to operate the pressure wave generator (1).

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