EP3776529B1 - Device for the production of high-amplitude pressure waves - Google Patents

Description

TECHNICAL AREA

The present invention relates to a device and a method for generating high-amplitude pressure waves, in particular for cleaning boilers.

STATE OF THE ART

Such a device for generating high-amplitude pressure waves is from U.S. 5,864,517 known. In the process, acoustic vibrations are generated that are significantly stronger than those that can be generated by loudspeakers. They can be used in particular for cleaning boilers, since these pressure waves cause particles to detach. In the U.S. 5,864,517 two different pulsed burns are discussed. The detonation and the deflagration. Detonative combustion has extremely fast flame velocities of 2,000 to 4,000 m/s, while deflagrative combustion has much slower flame velocities, such as less than 200 m/s, and the pressure waves are of significantly lower amplitude.

The EP 2 319 036 relates to a method and a device for generating explosions, in particular high-intensity pressure pulses. There is a pressure-resistant container with a main explosion chamber, as in the above-mentioned US patent, with an outlet opening for the pressure pulses and a piston closing the outlet opening. The position of the piston is shifted by an auxiliary explosion in an auxiliary explosion chamber in such a way that it releases the outlet opening. This procedure requires precise time coordination between the triggering of the main explosion and the preceding auxiliary explosion. The device then also has a gas spring chamber which brakes the pushed-back piston and, after the gases have been blown out of the main explosion chamber, pushes said piston back to its original position.

The EP 1 922 568 FIG. 1 shows another method and apparatus for generating explosions in which the gas spring mechanism includes a relief mechanism disclosed as an over-centre spring mechanism.

The article by Tibor Horst Füle "Cleaning technologies with sonic horns and gas explosions at the waste-fired power plant in Offenbach (Germany), Cleaning with sound and explosion generators in the Offenbach waste-to-energy plant" in VGB Powertech, Vol. 93, No. 8, August 1, 2013, pages 67-72, ISSN;1435-3199 also discloses a method and apparatus for generating explosions for cleaning with acoustic emissions.

Furthermore, the FR 2,938,623 an explosion cylinder having a piston movable between an open and a closed position for cyclically generating explosions of pressurized gas or air for cleaning purposes.

PRESENTATION OF THE INVENTION

Proceeding from this state of the art, the invention is based on the object of specifying an improved device which can be ignited more simply and reliably.

In addition, an object of the invention is to provide the device with a longer maintenance interval, since the wear and tear of the moving parts in the pressure-resistant container due to the explosions is considerable and, in the prior art, only allows a limited number of repetitions of the cleaning ignitions before the plant needs maintenance. Since the processes in power plant technology, the basic industry and in technical chemistry are usually carried out in complex chemical plants, a number of such devices for generating high-amplitude pressure waves are usually provided for cleaning the various containers, which then have to be serviced accordingly.

The device is preferred for cleaning boilers in large technical Plants such as waste incinerators, coal-fired power plants, silos, etc. used to remove slag or deposits. The main advantage there is that the individual cleaning cycles can be repeated very quickly and several times. Also, the use of gases as cleaning material for generating the sequence of pressure waves and associated pressure pulses is relatively cheap and high pressures can be generated. In addition, the delivery of two chemical fluids, which do not inherently burn up or explode, at a time just before the blast is triggered increases safety. It also enables cleaning of systems that are still warm and possibly in operation, since the reacting substances are exposed to the hot environment for a long time.

The pressure wave generated can be conducted via a pipe over long distances into a boiler at the point to be cleaned. The tube can be permanently installed on the system to be cleaned, but can also be inserted from the outside, for example pushed telescopically into a system or a boiler. Due to the pressure pulse generated during the burn-up, deposits and dirt are blown away from the inner pipes in the boiler and its walls and at the same time the pipes and walls vibrate. Both actions result in efficient cleaning of the systems to be cleaned.

Various other possible uses are conceivable in which a high, rapid force impulse, pressure pulse or pressure wave of high intensity and/or (rapid) repeatability is required. Examples are pressure generators for sheet metal forming or as propulsion systems for firearms, where the pressure pulse is used to accelerate a projectile. It is also possible to use such systems in the field of controlled avalanche release.

A device for generating high-amplitude pressure waves, in particular for cleaning boilers, has a pressure-resistant container. This can be in several parts. It has at least one combustion chamber incorporated therein. Several combustion chambers can be connected to each other. At least one ignition device reaching into the combustion chamber(s) is provided. There is at least one feed line for feeding a flowable combustible material into the combustion chamber, preferably separately a fuel and an oxidant, such as natural gas and air or methane and oxygen. Various other liquid or gaseous fuels can also be used. In this case, the pressure-resistant container has a discharge opening for the directed release of gas pressure generated by the ignition of the combustible material in the combustion chamber. Before and during the ignition, there is a closure means that closes the discharge opening, which is designed to release the discharge opening for the directed discharge, and which can then be pushed into the starting position by a spring device after the burnout. The closure means is a piston that can be displaced in its longitudinal direction and has a rear section that is oriented in the direction of the spring device and a front section that is oriented in the direction of the discharge opening.

In relation to its longitudinal direction, the seat of the piston has a piston surface that is inclined obliquely to the discharge opening, which is arranged opposite a housing surface that is also inclined obliquely to the discharge opening, with the housing surface being oriented relative to the piston surface at an angle towards the discharge opening from one perpendicular to the piston direction Closing line opens starting.

The angle can be between 0.5 and 5 degrees, preferably between 1 and 3 degrees, in particular 2 degrees.

The seal line perpendicular to the direction of the piston may be located within the piston wall of the lower portion such that there is a rounded static pressure opening area between the seal line and the piston wall.

A flange surface perpendicular to the piston axis, which is connected to the combustion chamber or belongs to it, can have a surface area that is between 50 and 200 percent of a surface area that is given by the surface area of the piston surface.

A transition area can be provided between these two sections. The front section is arranged in the area of the combustion chamber when the piston is in a position that closes the discharge opening. In relation to the longitudinal direction of the piston the front section is tapered compared to the rear section, so that the transition region forms an effective surface aligned transversely to the longitudinal direction of the piston, on which a pressure driving the piston back is exerted when the combustible material is ignited, so that the front section of the piston uncovers the discharge opening . This makes cleaning easier, since the pressure build-up can also be achieved by burning off and is then itself responsible for opening the path to the discharge funnel.

The transition area can be an area that tapers continuously in the longitudinal direction of the piston of the gas spring from a larger piston diameter to a smaller piston diameter, which is arranged in the area of the combustion chambers. On the other hand, the transition area can also be formed by a flange-like tapering of the piston.

In particular, a hollow central guide line can be provided in the pressure-tight container, which guides the piston in the front area in its interior. This has advantages when the piston guide wears out, since it allows for guidance over sections of the piston that are further apart. At least one connecting gap is then provided between the combustion chambers and an auxiliary pressure chamber in the area of the flange-like taper of the piston.

The combustion chamber can be arranged in a ring around the piston around its longitudinal axis. In particular, the ring-shaped walls of the combustion chamber can then be stacked and sealed ring segments which are advantageously closed off at the top and bottom by a cover plate and a base plate. The height and the volume of the cylindrical combustion chamber can thus be scaled in a simple manner, since no special chambers of different sizes have to be provided. The only thing that belongs to such a scaled combustion chamber is the piston, which is adjusted accordingly in terms of length, as the closure unit.

At least two combustion chambers can be arranged in one plane at an angular distance from one another radially to a central axis. In particular, two combustion chambers can be diametrically opposed. Then either the longitudinal axis of the gas spring together with the central axis; three combustion chambers could then be 120 degrees apart in the common plane. Or the longitudinal axis of the gas spring also lies in the said plane of the at least two combustion chambers, so that with three combustion chambers an angular distance of 90 degrees between the individual elements is possible.

As a rule, the discharge opening has a tube with a tube longitudinal direction. The longitudinal direction of the discharge opening can then either coincide with the central axis, i.e. the discharge opening can lie in the extension of the piston, or the longitudinal axis of the gas spring can lie in said plane of the at least two combustion chambers. Then, for example with two combustion chambers, an angular distance of less than 120 degrees can be provided between the two combustion chambers, so that they are more aligned with the discharge opening.

The gas spring can have a front gas spring chamber space opposite the piston and a rear gas spring chamber space separated from this by a partition wall, with a first connection as a return flow connection and a second connection with a check valve being provided between the front gas spring chamber space and the rear gas spring chamber space, the check valve being so is arranged to permit unrestricted flow of media from the front to the rear gas spring chamber but substantially block the reverse flow out of the rear gas spring chamber.

The first and the second connection can be provided in the partition wall. On the other hand, the second connection can have at least two partial connections which, on the one hand, open out laterally one above the other in the longitudinal direction of the piston movement in the wall of the gas spring in the front gas spring chamber space and, on the other hand, end in the rear gas spring chamber space, so that the openings occur one after the other when the piston penetrates into the front gas spring chamber space are covered, said sub-connections each having their own check valve. As a result, the individual non-return valves are switched off successively, so that the media flow from the front to the rear gas spring chamber slows down, i.e. the braking effect due to the gas pressure build-up in the front gas spring chamber decreases.

The second connection can have a controllable check valve, which can optionally have a control valve connected in series and a check valve, which controllable check valve is connected to a control unit, with which the ignition can be triggered, the control unit being designed to switch the controllable check valve in a first predetermined time interval after ignition of the flowable combustible material. This can ensure that the burnup in the burnup chamber is complete before the piston is allowed to retreat any further.

The first connection can have a controllable backflow valve, which can optionally have a control valve connected in series and a backflow guide, which controllable backflow valve is connected to the control unit, with which the ignition can be triggered, the control unit being designed to combine the controllable backflow valve in one to open second predetermined time interval after the opening of the controllable check valve. This makes it possible to activate the return flow later after the opening of the controllable non-return valve and thus the pressure equalization between the front and rear gas spring pressure chamber, i.e. to trigger the closing movement of the piston later in time, so that the combustion gases that are still under pressure completely leave the combustion chamber.

Two separate gas spring gas connections can also be provided for the front and rear gas spring chambers, with the control unit having a gas filling control unit with which the gas filling pressure in the front and rear gas spring chambers can be set to a predetermined value before ignition, the Gas filling pressure in the front gas spring chamber can be set higher than in the rear gas spring chamber. In particular, the gas filling pressure in the front gas spring chamber can be set at least 2 times, preferably at least 3 times or 5 times higher than in the rear gas spring chamber, so that on the one hand the front gas spring pressure chamber does not recede or only recedes insignificantly during ignition , since the pressure prevailing in it upon ignition opposes the pressure building up in the combustion chamber, and the retreat only occurs completely and quickly when the check valve is opened, since a gas pressure difference was set. In particular, the rear chamber can be at atmospheric pressure while only the front gas spring pressure chamber has been pressurized with the inert gas.

In order to solve the problem of specifying an improved device which can be ignited more easily and reliably, a device according to claim 1 is proposed, namely a device for generating pressure waves of high amplitude, in particular for cleaning boilers, with a pressure-resistant container with a combustion chamber installed therein and at least an ignition device reaching into the combustion chamber, with at least one supply line for supplying a free-flowing combustible material into the combustion chamber, the pressure-resistant container having a discharge opening for the directed release of gas pressure generated in the combustion chamber by the ignition of the combustible material and a closure means closing the discharge opening, which is designed to release the discharge opening for directed discharge, and which can be displaced into the starting position by a spring device, the closure means being a piston which can be displaced in its longitudinal direction and which has a rear section oriented in the direction of the spring device and a front section in the direction of the The front section is arranged in the region of the combustion chamber when the piston is in a position that closes the discharge opening, the seat of the piston having a piston surface inclined obliquely to the discharge opening in relation to the longitudinal direction of the piston, and the piston surface opposite the piston surface, which is also inclined the housing surface is arranged inclined toward the discharge opening, and wherein the housing surface opens relative to the piston surface at an angle oriented toward the discharge opening from a closure line oriented perpendicularly to the direction of the piston. In this case, this angle is advantageously between 0.5 and 3, in particular 1 degree. The closure line oriented perpendicular to the direction of the piston is advantageously arranged within the piston wall of the lower section, so that there is a rounded static pressure opening area between the closure line and the piston wall. Even with this device, the feature can be met that in relation in the longitudinal direction of the piston, the front section is tapered in relation to the rear section. The taper relates to the inner piston seat wall and then preferably has an opposite outer housing valve seat wall which opens inwards towards the outlet at a small angle.

Further embodiments are given in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

eine schematische perspektivische Ansicht einer Vorrichtung zur Erzeugung von Druckwellen hoher Amplitude gemäss einem Ausführungsbeispiel der Erfindung;

Fig. 2

eine schematische Ansicht der Vorrichtung nach Fig. 1;

Fig. 3

eine seitliche nicht massstabsmässige Schnittansicht einer Vorrichtung zur Erzeugung von Druckwellen mit ihren erfindungswesentlichen Komponenten;

Fig. 4A, 4B & 4C

in drei übereinanderliegenden Querschnitten drei horizontale Schnitte durch die Vorrichtung nach Fig. 3;

Fig. 5

eine schematische Detailansicht des Kolbens aus Fig. 3 zwischen den Linien IVb und IVc;

Fig. 6

eine schematische perspektivische Ansicht einer anderen Vorrichtung zur Erzeugung von Druckwellen hoher Amplitude gemäss einem Ausführungsbeispiel der Erfindung;

Fig. 7

eine schematische Querschnittsansicht mit vertikaler Schnittachse der Vorrichtung nach Fig. 6;

Fig. 8

eine schematische Querschnittsansicht mit horizontaler Schnittachse der Vorrichtung nach Fig. 6;

Fig. 9

eine schematische perspektivische Ansicht einer weiteren Vorrichtung zur Erzeugung von Druckwellen hoher Amplitude gemäss einem Ausführungsbeispiel der Erfindung;

Fig. 10

eine schematische Querschnittsansicht mit vertikaler Schnittachse der Vorrichtung nach Fig. 9;

Fig. 11

eine schematische Querschnittsansicht mit vertikaler Schnittachse einer Vorrichtung mit Merkmalen teilweise nach der Vorrichtung nach Fig. 6 und nach der Fig. 9;

Fig. 12

eine schematische Querschnittsansicht mit vertikaler Schnittachse eines Ausführungsbeispiels einer Gasfeder einsetzbar in einer Vorrichtung beispielsweise nach den Fig. 1, 6, 10 oder 11;

Fig. 13

eine schematische Querschnittsansicht mit vertikaler Schnittachse eines anderen Ausführungsbeispiels einer Gasfeder einsetzbar in einer Vorrichtung beispielsweise nach den Fig. 1, 6, 10 oder 11;

Fig. 14

eine schematische Teilansicht eines Mittelstücks einer Vorrichtung nach einem weiteren Ausführungsbeispiel der Erfindung, die auch in Fig. 2, 3, 7, 10 und 11 einsetzbar ist:

Fig. 15A, 15B und 15C

sind Detailansichten der Fig. 14 zu verschiedenen Zeitpunkten eines Öffnungszyklus; und

Fig. 16

ein Kraftverlaufs-Diagramm über die Zeit für das Ausführungsbeispiel des Ventilsitzes für eine Vorrichtung zur Erzeugung von Druckwellen hoher Amplitude.

Preferred embodiments of the invention are described below with reference to the drawings, which are for explanation only and are not to be interpreted as restrictive. In the drawings show:

1

a schematic perspective view of a device for generating high-amplitude pressure waves according to an embodiment of the invention;

2

a schematic view of the device 1 ;

3

a lateral sectional view, not to scale, of a device for generating pressure waves with its components essential to the invention;

Figures 4A, 4B & 4C

three horizontal sections through the device in three superimposed cross sections 3 ;

figure 5

a schematic detailed view of the piston 3 between lines IVb and IVc;

6

a schematic perspective view of another device for generating high-amplitude pressure waves according to an embodiment of the invention;

7

a schematic cross-sectional view with a vertical section axis of the device 6 ;

8

a schematic cross-sectional view with a horizontal cutting axis of the device 6 ;

9

a schematic perspective view of a further device for generating pressure waves of high amplitude according to an embodiment of the invention;

10

a schematic cross-sectional view with a vertical section axis of the device 9 ;

11

a schematic cross-sectional view with vertical section axis of a device with features partially after the device 6 and after 9 ;

12

a schematic cross-sectional view with a vertical section axis of an embodiment of a gas spring can be used in a device, for example according to 1 , 6 , 10 or 11 ;

13

a schematic cross-sectional view with a vertical section axis of another embodiment of a gas spring can be used in a device, for example according to 1 , 6 , 10 or 11 ;

14

a schematic partial view of a center piece of a device according to a further embodiment of the invention, which is also in 2 , 3 , 7 , 10 and 11 can be used:

Figures 15A, 15B and 15C

are detailed views of 14 at different times of an opening cycle; and

16

a force curve diagram over time for the embodiment of the valve seat for a device for generating pressure waves of high amplitude.

DESCRIPTION OF PREFERRED EMBODIMENTS

The figure 1 shows a perspective view of a device for generating high-amplitude pressure waves according to an embodiment of the invention. A first pressure-resistant container 21 and a second pressure-resistant container 22 are arranged to the left and right of a central body 30 . In the present exemplary embodiment, these containers 21 and 22 run essentially parallel to the boiler wall 5, a detail of which is shown. A drain funnel 61 with a downstream drain pipe 62 is also flanged to the central body 30 , which protrudes through the boiler wall 5 and ends in a drain opening 63 in the boiler interior 15 . In other exemplary embodiments, the discharge opening 63 can also be arranged directly on the boiler wall and the discharge pipe 62 can be made shorter than the discharge funnel 61 or can be omitted entirely. The gas spring pressure body 40 is flanged to the central body 30 opposite the discharge funnel 61 . In the lower area of the lower central body 30, a first gas reservoir 51 and opposite a second gas reservoir 52 are provided on the left and right. In other embodiments, the construction of the containers 21 and 22 may be longer, i.e. an aspect ratio for the internal volume 121 and 122 of between 5:1 and 20:1.

The functioning of the device for generating pressure waves will now be explained in conjunction with the schematic representation of the device 1 with the 2 described. This shows some key elements figure 1 in a schematic representation. The two left and right pressure-resistant containers 21 and 22 are arranged on the central body 30 and have a first combustion chamber 121 and a second combustion chamber 122, respectively. In the exemplary embodiment, the pressure-resistant containers 21 and 22 are cylindrical with an interior space that is larger in diameter in the rear area, ie the passage tapers towards the central body 30 .

A piston 70 is arranged in the central body 30, which will be shown in more detail in the further drawings, which in the closed state shown separates the chambers 121 and 122 from one another and closes the outlet in the direction of the discharge funnel 61 with its front end 72 of the piston 70. The piston 70 protrudes with its upper part 71 in the gas spring pressure body 40 as shown in FIG 3 is shown in more detail. The valve seat itself is identified by reference number 300 . This can in particular after the 14 and the detailed views of the Figures 15A, 15B, 15C be designed in order to then unfold the effect as shown in 16 is shown.

The object of the high-amplitude pressure wave generating device is to generate the same in the first and second pressure chambers 121 and 122 by burning a fluid fuel or explosive. This fuel is preferably formed by the mixing of components that are not combustible or explosive per se and that are stored in the first and second gas storage tanks 51 and 52 . These gas reservoirs 51 and 52 are fed via external gas supply lines 53 and 54 from corresponding gas connections 57 and 58 which are regulated via external gas supply line valves 55 and 56 . The first gas reservoir 51 is connected to the combustion chambers 121 and 122 via a first gas filling line 151 and an interposed first gas filling valve 153 . The representation of 2 with the connection to only one combustion chamber 121 is also possible if corresponding compensating lines are provided between the first and second combustion chambers 121 and 122. Correspondingly applies to the second gas connection 58 that the second Gas reservoir 52 is directly or indirectly connected to the combustion chambers 121 and 122 via the second gas filling line 152 and the second gas filling valve 154 . The embodiment shown corresponds to filling of the combustion chambers 121 and 122 via two dosing tanks with subsequent inflow into the device. Otherwise it is also possible to fill the device directly via panels.

Furthermore, a gas spring gas connection 47 is provided, with a gas spring supply valve 48 and a gas spring supply line 49, the gas for the gas spring 40 in the gas spring interior 41 and 42, as in FIG 3 to see is initiated.

In the present exemplary embodiment, reference is made to a first and a second gas. The first gas can be methane or natural gas, for example, while the second gas can be oxygen or air or an oxygen-containing air mixture. In other exemplary embodiments, the flowable combustible material may be an explosive mixture; in addition to gaseous material, it may also be liquid, powdery material or a mixture of such materials.

The combustion chambers 121 and 122 are additionally connected to an ignition device which triggers an ignition of the combustible material in the combustion chambers 121 and 122 at the same time. If, as in the embodiment of 6 an annular gap is provided, in short a volumetric connection of the two combustion chambers 121 and 122, then only one ignition device is necessary. Glow plugs or spark plugs, among others, can be used as the ignition device. An intensified ignition by means of a spark plug, which has a higher ignition energy than a glow plug, the speed of the reaction can be increased. A more rapid pressure build-up in the combustion chambers 121 and 122 thus takes place.

When the ignition is triggered, there is a controlled burning off or a controlled explosion of the combustible or explosive mixed components in the combustion chambers 121 and 122, which exert pressure on the piston 70 and there in particular on the intermediate area 75, as is the case in connection with the 3 will be described. This leads to a movement of the piston 70 in its longitudinal direction against the pressure of the gas spring 40, which at the same time quickly releases the connection between the combustion chambers 121 and 122 and the discharge funnel 61 opens.

The outlet opening of the pressure-tight container is kept closed beforehand by the piston 70 as the closing means. The gas spring allows the closure to be kept closed even against the filling pressure of the combustible elements in the combustion chambers 121 and 122. Only through the pressure increase when the flowable mixture is ignited is the pressure on the intermediate area 75 increased so that the piston 70 is pushed back accordingly. Then, as in connection with the 3 will be described, the gas spring element then also brings about a return of the piston 70 as a closing means after burning off and allows the process to be directly repeated by refilling the chambers 121 and 122. At the same time, substances in the boiler are reliably prevented from flowing back into the device.

The piston 70 is opened so quickly that the pressurized mixture in the combustion chambers 121 and 122 is still not completely burned when escaping, so that the gas mixture in the discharge funnel continues to burn, so that a pressure pulse with a high pressure peak is generated. If air is used as one of the two media in addition to CH ₄ or natural gas, the chemical reaction will take place within the combustion chambers 121 and 122 and all of the energy will be converted in the device. The gas is then released to the outside by a subsequent, ie time-delayed, rapid opening of the piston 70 after the initial pressure build-up.

The 3 shows a lateral sectional view in a schematic representation of a device for generating pressure waves with its components essential to the invention.

The first and second pressure-resistant containers 21 and 22 border on the discharge funnel 61 inserted in them, which has a rounded valve seat contact 65 at its inner end. The front end 72 of the piston 70 adjoins this valve seat contact 65, which is designed as a horizontal, essentially circular contact line running perpendicularly and concentrically to the longitudinal axis 90 of the piston, to which the tapered piston region 73 is connected. At this tapered piston area 73 A piston transition area 75 follows, in which the diameter of the piston is increased in order to have a larger diameter at the rear end of the piston 71 . The rear piston diameter 171 is thus designed to be larger than the front piston diameter 172; in particular, the piston 70 has a surface 91 as seen in its longitudinal direction (as in 4 designated) with a size that is sufficient to move the piston in the direction of the gas spring 40 upon ignition. The diameter and height of the cavities of the gas spring 40 can be selected to be larger in relation to the combustion chambers 121 and 122. The piston 70 is sealed between the walls of the left and right pressure-resistant vessels 21 and 22 by a series of seals 81 and 82 in its longitudinal direction, the three seals 81 being bronze seals, while the seal 82 sandwiched between them is an O ring is. These seals 81 and 82 are embedded in grooves in the piston 70; they could also be provided in the opposite walls.

The piston 70, which is thus passed through the central body 30 with the pressure-tight containers 21 and 22 in a sealing manner, then protrudes in a sealing manner against the front gas spring chamber space 41 in the gas spring pressure body 40, which is separated from the rear gas spring chamber space 42 by a gas spring partition 43. A check valve 44 and a gas return flow opening 45 are provided in the gas spring partition.

The function of the gas spring is as follows. The two components of the combustible gas mixtures are fed into the chambers 121 and 122 through the gas filling lines 151 and 152 . By one in the drawing of the 3 Not shown ignition device, these gases are ignited. As a result, pressure is exerted on the transition area 75 , which overcomes the gas spring pressure holding against it and moves the piston 70 into the area of the front gas spring chamber space 41 . To ensure that this movement takes place sufficiently quickly, the non-return valve 44 is provided in the intermediate wall 43, which opens immediately and quickly equalizes the gas pressure between the front gas spring chamber space 41 and the rear gas spring space 42, so that after an initially strong movement of the piston 70, this then increased resistance from the combined gas spring chamber 41 and 42 is braked. After the piston 70 has been pushed back in the direction of the intermediate wall 43, the combustible gases escape from the discharge funnel 61 in burnt or still burning form and reduce the pressure in the combustion chambers 121 and 122. Since the valve in the gas spring partition 43 is a non-return valve 44, the combination of the gas spring chambers 41, 42 is then only connected through the gas return flow opening 45, which is much smaller in diameter, with the then pushes back the gas of the gas spring from the rear gas spring chamber 42 into the front gas spring chamber 41 and pushes the piston 70 into its initial position, as shown in FIG figure 3 is shown pushes. Any gas losses are compensated for by the gas spring feed line 49 . The gas of the gas spring 40 can be air or an inert gas such as N ₂ .

The 4 shows in three superimposed cross sections Figures 4a, 4b and 4c three cross sections through the device 3 along the intersection lines IVa, IVb and IVc. The piston 70 advantageously has a round cross-section.

Figure 4a FIG. 8 shows a cross-section along the line IVa through the top wall 21, 22 of the pressure-tight containers, showing a bronze seal 81 surrounding the rear portion 71 of the piston 70. FIG.

In the Figure 4b a parallel sectional plane in the combustion chamber 121, 122 and through the combustion chamber 121, 122 is shown, which is a section along the line IVb in the upper area of the space of the combustion chambers 121 and 122, in which the piston 70 has the diameter of the rear area 71 has.

The Figure 4c then shows another section along the line IVc, parallel to the section of the Figure 4b in the lower area of the cavity, where it can be seen directly that the width of the piston 70 in the central chamber area 30 butts against the walls of the pressure-resistant container 21, 22 and thus has a width that remains constant over the length of the piston; on the other hand, the depth in the direction of longitudinal alignment of the inner spaces 121, 122 is made smaller. It can thus be seen directly here that there is a difference between the front piston diameter 172 and the rear piston diameter 171, the term piston diameter here corresponding to the width in the longitudinal direction of the combustion chambers 121, 122 lying opposite one another.

The vent opening 61 is here in all three drawings Figures 4a, 4b and 4c below the Character level shown. It is just as possible as it is in the 3 of the state of the art WO 2010/025574 It is shown that the discharge funnel 61 is connected to a combustion chamber 121 in the longitudinal direction of the extension on the other side of the central body 30 and the closure element as a piston 70 is perpendicular to it, so that the gas mixture escapes straight ahead in the longitudinal direction of the entire device when the piston 70 is pushed back can.

It is also possible to provide two, three, four or more combustion chambers which are in the plane of the combustion chambers 121 and 122 of FIG 1 , 2 or 6 are arranged corresponding to the cutting plane 92 in 7 , since in all cases here the piston 70 is perpendicular to said plane of arrangement of the combustion chambers and the discharge funnel 61. In an arrangement according to the WO 2010/025574 the discharge funnel 61 would be in the same plane as all the combustion chambers and could then, for example, be equiangularly spaced from all of them. With three combustion chambers then 90 degrees to each other. The combustion chambers opposite the discharge funnel 61 can also be arranged closer together, so that the outflow direction does not have to be changed as much.

The figure 5 shows an enlarged section of the transition area 75 of the piston 70.

It can be seen here that there is a first diameter 121 from the longitudinal axis 90 of the piston, which is designed to be smaller than the rear piston diameter 171 . The transition region 75 thus forms two rectangular strips 91 in a section in the projection of the longitudinal axis 90, which serve as pressure transmission strips. When the combustion chambers 121 and 122 are being filled, the pressure exerted on this strip 91 is not sufficient to push back the piston 70 against the pressure of the gas spring. This then changes abruptly after ignition of the gas mixture, since a pressure difference of up to 25 to 30 times the filling pressure can occur, which is then sufficient to drive back the piston 70 when the gas spring tension is adjusted accordingly. In the exemplary embodiments, the combustible chambers have a volume of between one and two liters, with the gas filling pressure being between 10 and 30, for example between 15 and 25 bar. The diameter of the annular opening closed by the piston is between 40 and 15 mm, in particular between 60 and 100 mm, in particular 80 mm.

Ignition can be performed in a manner similar to the prior art WO 2010/025574 be configured and thus happen, for example, electrically or by light ignition.

The 6 12 shows a schematic perspective view of another device for generating high-amplitude pressure waves according to an embodiment of the invention. The same features are provided with the same reference symbols throughout the description. Two pressure-resistant containers 21 and 22 are also arranged here on the central body 30 and the gas spring pressure body 40 is provided perpendicular to these. The gas filling lines 151 and 152 lead into the central body 30 and the supply line of the ignition device 50 is shown in the middle of the central body 30 .

The 7 FIG. 12 now shows a schematic cross-sectional view of the device 6 with a vertical cutting axis. The longitudinal axis 90 of the piston, which corresponds to the longitudinal axis of the gas spring pressure body 40, crosses the horizontal central section plane 92 of the pressure bodies 21 and 22. Elements of the central body 30 are shown in FIG 7 been omitted from the drawing for the sake of simplicity. In the lower area, the pressure-resistant containers 21 and 22 reach the discharge funnel 61 , the inner end of which forms the valve seat contact 65 for the piston 70 . The sealing line is a circular ring on the valve seat 300. The piston 70 has a tapered lower area 73, which is adjoined by the transition area 75, which increases in diameter and leads into the rear piston area 71. The piston 70 is hollow here. It may be in two parts, the lower end being insertable into the hollow piston 70 for contact with the valve seat 65 . The valve seat 300 can again as in FIG 14 shown, be executed.

The rear area of the piston 70 has a sufficient height from the transition area 75 to its upper flat end surface, which delimits the lower gas spring chamber space 41, so that even if the piston is pushed back into this front gas spring chamber space 41, the piston 70 still rests against the inner walls of the Gas spring 40 rests essentially sealingly through the following sealing elements. There are according to the embodiment of 7 two bronze guides 81 that around the piston 70, and a sealing O-ring 82 arranged between them. The bronze guides 81, which are arranged with a greater distance from one another, also have a sealing function and they, like the O-ring 82, are in corresponding circumferential grooves stored in the piston 70. The check valve 44 and the gas return flow opening 45 are provided in the gas spring partition 43, which runs essentially perpendicular to the longitudinal axis 90 of the piston. The gas return flow opening 45 can also be referred to as an orifice. The gas spring supply line 47 is led to the rear end of the gas spring chamber space 42 , with which an inert gas such as nitrogen, CO2 or argon can be refilled externally via the gas spring gas connection 49 . If the spring chamber spaces 41 and 42 are sufficiently sealed, the gas can also be air.

The 8 shows the embodiment of 6 in section plane 92. It can be seen that the piston 70 is arranged at a constant distance in this central area from the inner wall of the central body 30 and that there is an annular gap 123 that extends in the piston longitudinal axis direction 90, which is used to equalize the pressure between the two combustion chambers 121 and 122 are designed. Thus, in the present exemplary embodiment, a gas supply line 151 and 152 arranged next to one another is sufficient for the two gases or fluids to be mixed for combustion. Centrally in the annular gap 123 between the combustion chambers 121 and 122, preferably also in the middle of the central body, the glow plug or spark plug 59 is arranged reaching into the annular gap 123, which is connected to the line 50 of the ignition device. Screens or metering valves 153 and 154 are provided here, so that the combustion chambers 121 and 122 are filled directly.

Such an annular gap 123 can also be guided on one side, ie only on the side of the spark plug 59, and it can also be used in other exemplary embodiments with two or more other combustion chambers.

The 9 shows a schematic perspective view of a further device for generating pressure waves of high amplitude according to an embodiment of the invention. An arrangement that is symmetrical about the longitudinal axis 90 of the piston has been provided here. In particular, an annular pressure-resistant container 25 is provided in which the gas supply lines 151 and 152 lead. This pressure-resistant container 25 is arranged below the gas spring pressure body 40 in its extension, and the ignition device supply line 50 is guided into the interior of the device through the section of the pressure-resistant container 25 that protrudes beyond the gas spring body. The pressure-resistant container 25 is made up of a cover plate, a base plate and here a ring, which are placed against one another in a sealing manner. Several rings can also be arranged one above the other.

The 10 FIG. 12 shows a schematic cross-sectional view with a vertical section axis of the device 9 .

The gas spring 40 is formed analogously to the other exemplary embodiments. There are two significant structural differences from these other embodiments which have been used together here. In other exemplary embodiments not shown in the figures, however, it is also possible to combine only one of the two differences described below with the other exemplary embodiments.

The first difference from the other embodiments is that there is an annular combustion chamber 125 that completely surrounds the piston 70 . Thus, there are ring-shaped elements of a pressure-resistant container 25. Here there are three rings, which due to the smooth, flush outer surfaces in 9 have been drawn as a ring. The spark plug 59 of the igniter 50 is sealed into the annular combustion chamber 125 through the top wall plate. Elsewhere, here in the 10 shown from below, the two gas supply lines 151 and 152 are introduced directly. In other words, there are no gas reservoirs 51 and 52 as dosing elements. This is controlled by the orifices 153 and 154 during filling.

The second difference between the other embodiments and the embodiment of figs 9 and 10 lies in the design of the piston 70. The projection of the pressure surface 91 of the other exemplary embodiments is formed here by an underside 191 of the piston 70, which underside and inside of the piston delimit an auxiliary pressure chamber 95. On its underside, this borders on a down tapering deflection profile strand 96. The strand 96, which is hollow here, has a uniform inner diameter, into which the lower section with the tapered piston region 173 runs, which is guided opposite the strand 96 via two bronze seals 81 here. When the combustible gas mixture supplied from the lines 151 and 152 is ignited by the spark plug 59, the pressure in the annular combustion chamber 125 increases as in the previous examples, with the pressure having the opportunity here to expand via a connecting gap 126 into the auxiliary pressure chamber 95 . Several such gaps 126 can also be provided, preferably at regular angular distances from one another, so that the deflection profile strand 96 is fastened to the plate or the gas spring pressure body through the connecting gaps 126, except for these interruptions.

Thus, shortly after ignition, the internal pressure of the annular combustion chamber 125 acts on the underside of the rear end 71 of the piston 70 with its surface 191 projecting beyond the core in the auxiliary pressure chamber 95. Thus, the pressure exerted on this surface 191, which corresponds to the pressure on the projection corresponds to the pressure surface 91 from the other exemplary embodiment, the piston 70 in its line 96 is pushed backwards into the front gas spring chamber space 41 by the enlarging auxiliary pressure space 95, with a bronze seal 81 and an O-ring 82 are provided.

When the piston 70 retreats, the connection between the ring-shaped combustion chamber 125 and the discharge funnel 61 (not shown here), which is characterized by the distance below the branch 96 and the valve seat 65, opens. In this case, too, the pressure of the burning or the detonation of the media existing in the annular combustion chamber space 125 acts on the retreating piston 70.

The 11 FIG. 9 shows a schematic cross-sectional view with vertical section axis 90 of a device with features which partially correspond to the device 6 correspond and in part to those of 9 or 10.

It is a piston 70 according to the embodiment of 1 and 6 , Which is surrounded by an annular combustion chamber space 125, as in the embodiment of FIG 9 and 10 is shown. Thus, the annular gap 123 is widened here to form the annular chamber space 125 and instead of two combustion chambers 121 and 122 lying opposite one another, there is only one cylindrical one with a piston 70 as the core. Otherwise, the function of pushing back the piston 70 is solved in exactly the same way by the pressure exerted on the transition area 75 by the burning gas mixture. In the 11 1, the gas spring pressure body is shown as a one-piece element with the cover of the annular (taking into account the inserted piston 70 as a central element) or otherwise cylindrical combustion chamber 125. Of course, this can also be several elements flanged together. What is important in the illustration here is that the walls surrounding the rear section of the piston 70 have extensions 196 which protrude into the interior of the combustion chamber 125 . These extensions 196, which are ring-shaped here, correspond to the strand 96 from the 10 and are used for further guidance of the piston 70. They can also correspond to bronze rings 81 opposite, which are embedded in the piston 70. In other words, it is advantageous to guide the piston 70 over a greater length, and this can be realized by a line guided in the middle or by extensions 96 in the form of rings or ring segments.

The piston 70 itself can be designed hollow to save weight, whereby it can be open to the front in the longitudinal direction 90 on the inside, or it can also be made of a solid material, in particular steel, or it can be hollow and have a front-inserted, in particular have screwed-in plugs. This can also form the sealing surface for the valve seat 65 .

The 12 shows a schematic cross-sectional view with vertical section axis 90 of another embodiment of a gas spring 140, wherein the further area of the device with the piston 70 and the spark plug 59 and the combustion chambers and discharge funnels, not shown here, can be configured similarly or identically. The essential difference to the gas spring 40 consists in an external bypass of the check valve 44 outside the pressure body as well as the external bypass of the gas return flow opening 45 outside of the pressure body. So both will not be inside of the gas spring partition 43 between the two spaces 41 and 42 but have external valves 144 and 145. These diaphragms or control valves 144 and 145 are connected to the control line labeled 150, which is also connected to the ignition device. The line 150 does not indicate a direct electrical or otherwise directly electrically activating line, but symbolizes that a control unit, not shown in the drawings, transmits control signals to the spark plug 59 and to the valves 144 and 145, so that they switch with a corresponding time delay . After the ignition, the non-return valve 44 is first switched continuously by the valve 144, optionally with a slight delay, in order to initially brake the movement of the piston by means of a rapid pressure build-up in the front gas spring chamber 41 and, after opening, to quickly equalize the pressure with the rear gas spring chamber 42 to reach. The valve 145 for the return flow opening 45 is closed. It can also open in advance, as it only lets a small amount of gas through in the opposite direction. Then, when all the gas has burned and the pressure from the chambers 41 and 42 is supposed to drive the piston back, the orifice 145 opens and closes the valve 144. With such controlled valves, it is also no longer necessary to use the elements 44 and 45 as design check valve or aperture; it can also be simple lines.

The 13 Finally, a further schematic cross-sectional view with a vertical section axis 90 shows another exemplary embodiment of a gas spring 240, which can also be used in a device, for example according to FIG 1 , 6 , 10 or 11 can be used. Here the non-return valve 244 is fourfold, while the gas return flow opening 45 is arranged in the gas spring intermediate wall 43 as in the other exemplary embodiments. The arrangement of four check valves 244, which is connected to the rear gas spring chamber space 42 via corresponding individual lines 243, results in an additional function in conjunction with the receding piston 70. The individual openings 246 of the four check valves 244 are arranged one above the other at intervals along the Piston longitudinal axis 90 is provided (not necessarily directly above one another, but also possible laterally offset at an angular distance from one another), so that the receding piston 70, gradually moving from below, breaks the orifices 246 one after the other and thus the connection to the check valves 244 from the connection between the front gas spring chamber 41 and the rear gas spring space 42 interrupts. Thus, with increasing piston travel, i.e. the retreat of the piston 70 into the gas spring 240, the gas pressure equalization between the front and rear spring chambers 41 and 42 via the check valves 244 is gradually reduced, which leads to a softer braking of the piston 70 in the front gas spring chamber 41. without the need for more complicated controls of valves. The check valves 244 are closed purely mechanically.

All above related to the Figures 1 to 13 illustrated embodiments can additionally or exclusively with the in connection with the 14 be configured valve seat 300 explained, whose operation in detailed views of a cross section through the valve seat 300 in the Figures 15A to 15C is explained and its measured effects on the course of force acting on the piston 70 over time in FIG 16 are shown.

The 14 shows a sectional view of an outer wall 172 of a piston 70 of an exemplary embodiment of a valve seat 300 with further features. The outer wall is in the 14 on the opposite wall of the gas spring pressure body 40; however, it can also be in contact with the guide strand 96 . At this time, the valve seat 300 is supported downward by mating surfaces of the exhaust gas funnel 61 . Between the exhaust gas funnel 61 and the gas spring pressure body 40 there is an opening which leads into the first combustion chamber 121 . Instead of the upper section of the exhaust gas funnel 61, a defined opposing surface can also be present, which is assigned to the pressure-resistant containers 21, 22, for example. The view of 14 is closed off at the upper piston end by the piston surface 170, which is perpendicular to the side wall of the front piston diameter 172 and above which the (front) gas spring chamber space 41 is provided. This configuration is in the embodiments of 2 , 3 , 7 , 10 , 11 usable. Here is shown an embodiment similar to that of FIG 10 , in which an auxiliary pressure chamber 95 is provided, in which a flange surface 191 is a pressure surface for moving the piston 70.

A line 301 is drawn on the valve seat 300 which indicates a distance from the side wall of the piston diameter 172 . This is a distance from a bend R2 belongs, which belongs to the inner piston seat wall 302 from the side wall 172, which is better seen in the detailed views of FIGS Figures 15A to 15C can be seen. This inner piston seat wall 302 is opposite the outer or housing-side valve seat wall 303. It is essential here that the two walls 203 and 303, which essentially form an angle of about 45 degrees, in other exemplary embodiments that are not shown, between 30 and 60 degrees, relative to the axis of piston movement 305 have, are not parallel to each other, but have an angle 304, which in the embodiment of FIG 14 is specified as 1 degree, but can also be formed between 0.5 and 5 degrees, in particular between 1 and 3 degrees.

The peak of the opening angle 304 is located at the intersection of the line 301, which indicates the end of the curvature of the piston 70, with the opposite outer housing-side wall 303 and closes there in a circular ring the outer discharge funnel space 306 of the (here shown) first combustion chamber 121, but naturally also in relation to the second combustion chamber 122 .

This configuration of the valve seat 300 is in the course of time in the explosive opening of the piston path in the Figure 15A (beginning 0.5 mm), Figure 15B (opening 1mm), Figure 15C (Clear passage 2mm) shown, with reference to the power relationships will be pointed out in the 16 are shown. In the 14 and the Figure 15C (Only in this one due to the lack of space) arrows 311, 312, 313, 314 and 315 are drawn. These stand for the entire surfaces on which they stand. If present, these are the optional antechamber surface 311, the static auxiliary surface 312, the dynamic auxiliary surface 313, the piston inner surface 314 and the gas spring surface 315 diametrically opposed to all of these.

The optional antechamber surface 311 is the flange widening in the auxiliary chamber pressure space 95. The static auxiliary surface 312 is the curved surface that is defined by the distance 301 and the radius R2 corresponding to it at the front end of the piston in 14 results, which then, in the mathematical sense, continuously merges into the inner piston seat wall 302. The dynamic auxiliary surface 313 is so called because the angle 304 causes the two walls 302 and 303 to diverge in the direction of the discharge funnel space 306 and the surface thus develops dynamically. Here the arrows would be 313 in a sequence from the inside edge to near the arrow 312. Finally, the piston inner surface 314 is shown here in the depression of the hollow piston, but it could also exist at the lower end of the piston. The gas spring surface 315 is provided diametrically opposite.

The 16 shows the force on the piston 70 on the Y-axis versus time on the X-axis. The basic effect of the auxiliary pressure chamber 95 and its area 311 is characterized by the line 411. The area 511 between the 0 line and the line 411 is therefore a key figure for the antechamber effective area. Line 412 shows the additional force resulting from the rounded area at arrow 312 and identified by area 512 between line 411 and line 412 .

This force builds up until the piston 70 unseats at time 520 . Then the dynamic area 313 comes into play and results in a boost indicated by line 413, the effect being indicated by area 513 located between lines 412 and 413 as a force increase. A little later and with a slight delay, the counteraction of the gas spring 40 sets in, the force effect of which is shown as a solid line 415 .

The increase in force referred to as boost ends at a point in time with a reversal of the boost curve 413 at a somewhat later point in time 521, at which the diverging gap after Figures 15A to 15C to a culvert as in Figure 15C has widened. This does not mean that there is a slot with a width of 2 millimeters, it depends on the depth of the valve seat, i.e. the distance from the curve R2 (described by the line / arrow 301) to the start of the discharge funnel space 306 At this point in time 521, line 414 separates from line 413 in the downswing area.

With the line 414 and the associated force effect in the area 415, the emptying of the piston chambers is added in the downswing area, with the characteristic curve 419 then developing as a sum line and oscillating in opposition to the gas spring line. In summary, the geometry of the valve seat has a positive effect on the opening behavior of the piston. During opening, the narrowest shifts Cross-section radially from the outside to the inside, resulting in the advantages of small projected areas when closed, which prevents unwanted opening. In the illustrated embodiment, the antechamber 95 ensures the initial opening at the desired time. However, it is possible to use this auxiliary chamber by arranging the surfaces 191 in the main chamber space 121 (i.e. without separate ignition, similar to the exemplary embodiment in figure 10 ) so that area 511 corresponds to incipient ignition of the main chamber.

Due to the fact that the narrowest cross-section shifts radially from the outside inwards, the enlargement of the active area leads to a boost effect of the piston movement immediately after the initial opening, which in the Figures 15A to C are shown in the initial opening movement. REFERENCE LIST 5 boiler wall 72 front end of the piston 10 contraption 73 tapered piston area 15 boiler interior 75 piston transition area 21 right pressure-resistant container 81 bronze seal 22 left pressure-resistant container 82 o ring 25 annular pressure vessel 90 longitudinal axis of the piston 30 central body 91 Projection of the print area 40 gas spring pressure body 92 horizontal plane 41 front gas spring chamber space 95 auxiliary pressure room 42 rear gas spring chamber space 96 guiding line 43 gas spring partition 121 first combustion chamber 44 check valve 122 second combustion chamber 45 gas return port 123 combustion chamber annular gap 47 gas spring gas connection 125 annular combustion chamber 48 gas spring supply valve 126 tapering strand 49 gas spring lead 140 gas spring 50 ignition device 144 check control valve 51 first gas tank 145 backflow control valve 52 second gas tank 151 first gas filling line 53 first external gas supply line 152 second gas filling line 54 second external gas supply line 153 first gas filling valve 55 first gas supply valve 154 second gas filling valve 56 second gas supply valve 170 piston surface 57 first gas connection 171 rear piston diameter 58 second gas connection 172 front piston diameter 59 spark plug 173 tapered piston area 61 discharge funnel 175 piston flange transition 62 drain pipe 191 flange face 63 drain hole 196 annular guide extensions 65 valve seat contact 70 Pistons 240 gas spring 71 rear end of the piston 243 connection line 246 line mouth 315 gas spring surface 300 valve seat 411 antechamber line of action 301 Line indicating end of curvature 412 static area action line 413 boost line of action 302 inner piston seat wall 414 flask emptying line 303 outer housing-side valve seat wall 415 gas spring line of action 419 sum line 304 Angle between 302 and 303 511 antechamber effective area 305 Piston movement axis (opening) 512 static effective surface 513 Boost Effect Area 306 drain funnel room 514 piston purge effective area 311 antechamber area 520 piston opening timing 312 static auxiliary surface 521 Passage at piston seat open 313 dynamic help surface 314 piston inner surface

Claims (15)

1. A device for generating high-amplitude pressure waves, in particular for boiler cleaning, comprising a pressure-resistant container (21, 22, 25, 30, 40) with a combustion chamber (121, 122; 125) inserted therein and at least one ignition device (50, 59) extending into the combustion chamber (121, 122), with at least one feed line (151, 152) for supplying a flowable combustible material into the combustion chamber (121, 122, 125), wherein the pressure-resistant container (21, 22, 25, 30, 40) has a discharge opening (61, 62, 63) for the directed discharge of gas pressure caused by the ignition of the combustible material in the combustion chamber (121, 122) and a closure means (70) which closes the discharge opening (61, 62, 63) and is designed to release the discharge opening (61, 62, 63) for the directed discharge and which is displaceable into the starting position by a spring device (40, 140, 240), the closure means (70) being a piston which can be displaced in its longitudinal direction and has a rear section aligned in the direction of the spring device (40, 140, 240) and a front section (72) oriented in the direction of the discharge opening (61), wherein the front section (72) is arranged in the region of the combustion chamber (121, 122, 125), when the piston (70) is in a position closing the discharge opening (61), wherein, with respect to the longitudinal direction (90) of the piston (70), the seat of the piston (70) has a piston surface (302) which is inclined obliquely with respect to the discharge opening (61), opposite which is arranged a housing surface (303) likewise inclined obliquely with respect to the discharge opening (61), characterized in that the housing surface (303) opens with respect to the piston surface (302) at an angle (304) oriented towards the discharge opening (61), starting from a closure line (65) oriented perpendicularly with respect to the piston direction (90).
2. The device according to claim 1, wherein the angle (304) is between 0.5 and 5 degrees, preferably between 1 and 3 degrees, in particular 2 degrees.
3. The device according to claim 1 or 2, wherein the closure line (65) oriented perpendicularly to the piston direction (90) is arranged within the piston wall of the lower section (72), so that a rounded static pressure opening area (312) exists between the closure line (65) and the piston wall.
4. The device according to any one of claims 1 to 3, wherein a flange surface (191) perpendicular to the piston axis (90), which is connected to or belongs to the combustion chamber (121, 122, 125), has an area size which is between 50 and 200 percent of an area size given by the area size of the piston surface (302).
5. The device according to any one of claims 1 to 4, characterized in that a transition region (75, 175) is provided between the rear portion (71) and the front portion (72), in that the front portion (72) is arranged in the region of the combustion chamber (121, 122) when the piston (70) is in a position closing the discharge opening (61, 62, 63), in that, with respect to the longitudinal direction (90) of the piston (70), the front section (72) is designed to be tapered with respect to the rear section (71), so that the transition region (75, 175) forms an active surface (91) which is aligned transversely with respect to the longitudinal direction (90) of the piston (70) and on which, when the combustible material is ignited, a pressure which drives the piston (70) back is exerted, so that the front section (72) of the piston (70) clears the discharge opening (61, 62, 63).
6. The device according to claim 5, wherein the transition region (75) is a region tapering steadily in the longitudinal direction of the piston (70) of the gas spring (40, 140, 240) from a larger piston diameter (171) to a smaller piston diameter (172) located in the region of the burn-off chambers (121, 122, 125).
7. The device according to claim 5, wherein the transition region (175) is formed by a flange-like (191) taper of the piston (70).
8. The device according to claim 7, wherein a hollow central guide strand (96) is provided in the pressure-resistant container (30) or an annular guide extension is provided on the pressure-resistant container (30) leading into the combustion chambers (121, 122, 125), which in its interior guides the piston (70) in the front region (72), and in that at least one connecting gap (126) is provided between the combustion chambers (121, 122, 125) and an auxiliary pressure space (95) in the region of the flange-like taper (191) of the piston (70).
9. The device according to any one of the preceding claims, wherein the combustion chamber (125) is arranged annularly or cylindrically around the piston (70) about its longitudinal axis (90).
10. The device according to claim 9, wherein the annular walls (25) of the combustion chamber (125) are stacked annular segments connected in a sealing manner, which are advantageously closed off by a cover plate and a bottom plate at the top and bottom, respectively.
11. The device according to any one of the preceding claims 5 to 8, wherein at least two combustion chambers (121, 122) are arranged in one plane at an angular distance from each other radially to a central axis, wherein either the longitudinal axis of the gas spring (40, 140, 240) coincides with the central axis or the longitudinal axis of the gas spring (40, 140, 240) lies in said plane of the at least two combustion chambers (121, 122).
12. The device according to claim 11, wherein the discharge opening (61, 62, 63) has a tube with a longitudinal tube direction, wherein either the longitudinal tube direction of the discharge opening (61, 62, 63) coincides with the central axis or the longitudinal axis of the gas spring (40, 140, 240) lies in said plane of the at least two combustion chambers (121, 122).
13. The device according to any one of the preceding claims, wherein the gas spring (40, 140, 240) has a front gas spring chamber space (41) located opposite the piston (70) and a rear gas spring chamber space (42) separated therefrom by a partition (43), wherein between the front gas spring chamber space (41) and the rear gas spring chamber space (42) there is a first connection as a return flow connection (45) and a second connection with a non-return valve (44), wherein optionally either the first and the second connection are provided in the partition (43), or the second connection has at least two partial connections (243) which, on the one hand, open laterally one above the other in the longitudinal direction of the piston movement in the wall of the gas spring (240) in the front gas spring chamber space (41) and, on the other hand, end in the rear gas spring chamber space (42), so that the openings (246) are covered one after the other when the piston (70) enters the front gas spring chamber space (41), the said partial connections (243) each having a non-return valve (44).
14. The device of claim 13, wherein said second connection comprises a controllable check valve (44, 144), optionally comprising a control valve (144) connected in series and a check valve (44), said controllable check valve (44, 144) being connected to a control unit by means of which the ignition (50) is triggerable, said control unit being configured to open said controllable check valve (44, 144) at a first predetermined time interval after ignition of said flowable combustible material, wherein optionally said first connection comprises a controllable check valve (45, 145), optionally comprising a control valve (145) connected in series and a backflow guide (45), said controllable check valve (45, 145) being connected to said control unit by means of which said ignition (50) is triggerable, said control unit being arranged to open said controllable check valve (45, 145) at a second predetermined time interval after opening of said controllable check valve (44, 144).
15. The device according to claim 14, wherein two gas spring gas connections are provided for the front and for the rear gas spring chamber (41, 42), wherein the control unit comprises a gas filling control unit by means of which the gas filling pressure in the front and in the rear gas spring chamber (41, 42) can be set to a predetermined value in each case before an ignition, wherein the gas filling pressure in the front gas spring chamber (41) can be set higher than in the rear gas spring chamber (42), in particular the gas filling pressure in the front gas spring chamber (41) can be set at least 2 times, preferably at least 3 times or 5 times, higher than in the rear gas spring chamber (42).

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