Pressure wave generator and method of operating a pressure wave generator

Abstract

A method of operating a pressure wave generator ( 1 ) with 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 ) with respect to an outlet ( 15 ) and, in an open position, allows a working medium to flow out of the pressure chamber ( 2 ) into the outlet ( 15 ); an actuator by means of which the closure element ( 9 ) can be brought from the closed position into the open position and, in particular, can also be brought from the open position into the closed position; wherein the method comprises repeatedly performing the following steps: filling the pressure chamber ( 2 ) with a gaseous working medium at a pressure of over one hundred bar; moving the actuator and thereby moving the closure element ( 9 ) in an opening direction to open the pressure chamber ( 2 ) with respect to the outlet ( 15 ), and discharging the pressurized working medium from the pressure chamber ( 2 ) through the outlet ( 15 ) within a discharge time period of less than fifteen milliseconds.

1 . A pressure wave generator comprising a pressure chamber, as well as
 a closure element which, in a closed position, closes the pressure chamber with respect to the outlet and, in an open position, allows a working medium to flow out of the pressure chamber into the outlet;   an actuator by which the closure element can be brought from the closed position into the open position and from the open position into the closed position;   wherein a volume of the pressure chamber is more than three liters;   wherein an area at the narrowest point of the outlet is more than twenty square centimeters;   wherein a stroke of the closure element during the opening and closing movement is between thirty and one hundred and fifty millimeters:   
       wherein the pressure wave generator is configured to repeatedly perform the following steps:
 filling the pressure chamber with a gaseous working medium at a pressure of over one hundred bar; 
 moving the actuator and thereby moving the closure element in an opening direction to open the pressure chamber with respect to the outlet, and discharging the pressurized working medium from the pressure chamber through the outlet within a discharge time period of less than fifteen milliseconds. 
 
     
     
         2 . The pressure wave generator according to  claim 1 , wherein a closure area of a closure opening, which is respectively closed and opened by the closure element, is at least as large as the area at the narrowest point of the outlet. 
     
     
         3 . The pressure wave generator according to  claim 1 , wherein the closure element is hollow cylindrical and is arranged to close or open a closure opening corresponding to a cylindrical surface. 
     
     
         4 . The pressure wave generator according to  claim 1 , wherein, during the opening movement of the closure element starting from an end position in which the closure element closes the closure opening, the closure element opens the closure opening only after covering a minimum distance which is different from zero. 
     
     
         5 . A pressure wave generator comprising a pressure chamber, and
 a closure element which, in a closed position, closes the pressure chamber with respect to an outlet and, in an open position, allows a working medium to flow out of the pressure chamber into the outlet;   an actuator by which the closure element can be brought from the closed position into the open position and from the open position into the closed position;   a heater, which is arranged to heat a working medium supplied to the pressure chamber or a working medium present in the pressure chamber, in particular wherein the heater is an electric heater;   
       wherein the pressure wave generator is configured to repeatedly perform the following steps:
 filling the pressure chamber with a gaseous working medium at a pressure of over one hundred bar; 
 moving the actuator and thereby moving the closure element in an opening direction to open the pressure chamber with respect to the outlet, and discharging the pressurized working medium from the pressure chamber through the outlet within a discharge time period of less than fifteen milliseconds; 
 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, in particular to a temperature of 200 degrees Celsius to 450 degrees Celsius. 
 
     
     
         6 . A pressure wave generator comprising a pressure chamber, as well as
 a closure element which, in a closed position, closes the pressure chamber with respect to the outlet and, in an open position, allows a working medium to flow out of the pressure chamber into the outlet;   an actuator by which the closure element can be brought from the closed position into the open position and from the open position into the closed position;   a pneumatic actuator which comprises
 a first piston surface which acts against a gaseous control medium in a first volume, wherein a pressure in the first volume causes an actuator force on the first piston surface in a first direction; 
 a second piston surface which acts against the control medium in a second volume, wherein a pressure in the second volume on the second piston surface causes an actuator force in a second direction opposite to the first direction; 
   
       wherein the closure element can be brought from the closed position into the open position by the pneumatic actuator and in particular can also be brought from the open position into the closed position; 
       wherein the pressure wave generator is configured to repeatedly perform the following steps:
 filling the pressure chamber with a gaseous working medium at a pressure of over one hundred bar; 
 moving the actuator and thereby moving the closure element in an opening direction to open the pressure chamber with respect to the outlet, and discharging the pressurized working medium from the pressure chamber through the outlet within a discharge time period of less than fifteen milliseconds; 
 
       wherein the step of opening the pressure chamber comprises the following steps:
 discharging at least part of the control medium from the first volume, in particular by opening an inlet/outlet opening of the first volume, and thereby opening the pressure chamber; 
 by a faster pressure drop in the first volume than in the second volume, moving the actuator in the second direction and thereby moving the closure element in an opening direction to open the pressure chamber with respect to the outlet, and discharging the working medium from the pressure chamber through the outlet. 
 
     
     
         7 . The pressure wave generator according to  claim 6 , wherein the step of opening the pressure chamber further comprises the following steps before discharging at least part of the control medium from the first volume:
 filling the first volume with a pressurized gaseous control medium, in particular by means of a filling valve, for example a compressed air valve;   pressure compensation between the first volume and the second volume by a throttle and thereby, due to a surface difference of the first piston surface and the second piston surface, moving the actuator in the first direction and thereby moving a closing element in a closing direction and closing the pressure chamber;   filling the pressure chamber with a gaseous working medium.