Membrane Pump and Method for Adjusting Same

Abstract

The present invention concerns a pump adjusting method and a membrane pump having a pumping chamber, a pressure and a suction connection, wherein the pressure and the suction connections are connected to the pumping chamber, a hydraulic chamber, wherein the pumping chamber and hydraulic chamber are separated from each other by a membrane, wherein a pulsating working fluid pressure can be applied to the hydraulic chamber which can be filled with a working fluid, wherein the membrane is moved between a first and second chamber positions of different volumes, wherein the chamber is connected to a working fluid reservoir, wherein the membrane comprises exchangeable spring elements exerting different forces on the membrane. The force which is exerted by the spring element on the membrane in the direction of the second position can be adjusted.

1 . A membrane pump with
 a pumping chamber;   a pressure and a suction connection,   wherein the pressure and the suction connections are connected to the pumping chamber;   a hydraulic chamber,   wherein the pumping chamber and hydraulic chamber are separated from each other by a membrane,   wherein a pulsating working fluid pressure can be applied to the hydraulic chamber which can be filled with a working fluid,   wherein the membrane is moved between a first position in which the pumping chamber has a smaller volume, and a second position, in which the pumping chamber has a larger volume,   wherein the hydraulic chamber is connected to a working fluid reservoir via a leakage compensation valve,   wherein the membrane comprises a spring element having a first spring constant, which is designed such that it exerts a first predetermined force on the membrane in the direction of the second position; characterized in that the spring element can be exchanged for another spring element which is designed such that it exerts a second predetermined force on the membrane in the direction of the second position, or the force which is exerted by the spring element on the membrane in the direction of the second position can be adjusted.   
     
     
         2 . A membrane pump according to  claim 1 , characterized in that the spring element can be detached from the membrane. 
     
     
         3 . A membrane pump according to any one of  claims 1  and  2 , characterized in that a hydraulic body and a membrane body are provided, between which the membrane is clamped, such that the hydraulic chamber is disposed in the hydraulic body and the pumping chamber is disposed in the membrane body, wherein the hydraulic body comprises a closeable opening disposed in the direction of force of the spring element, through which the spring element can be changed or adjusted. 
     
     
         4 . A membrane pump according to one of  claims 1  to  2 , characterized in that the pulsating working fluid is supplied to the hydraulic chamber via a channel, wherein the channel is orientated, at least in the region of its opening into the hydraulic chamber, such that it forms an angle α with the direction of force of the spring element which is >0°, preferably >45°, particularly preferably >70° and most preferably approximately 90°. 
     
     
         5 . A membrane pump according to one of  claims 1  to  2 , characterized in that the hydraulic chamber is connected to a working fluid reservoir via a leakage compensation valve, wherein the leakage compensation valve comprises a closing body which is movable to and fro between a closed position in which the valve gate is closed and an open position in which the valve gate is open, which closing body is held in the closed position with the aid of a pressure element, wherein the pressure element is designed such that if the pressure in the hydraulic chamber is lower than a set pressure p L , the closing body moves in the direction of the open position. 
     
     
         6 . A membrane pump according to  claim 5 , characterized in that the pressure element of the leakage compensation valve and the spring element of the membrane are constructed and arranged such that at any time the sum of the hydraulic chamber pressure p H  and the force p FV  applied by the spring element to the working fluid is higher than the set pressure p L . 
     
     
         7 . A membrane pump according to  claim 6 , characterized in that the mass of the closing body ( 16 ) is such that the closing body ( 16 ) moves by not more than 0.2 mm, preferably not more than 0.1 mm, in the direction of the open position when a pressure drop to 0 bar which lasts no longer than 1 ms occurs as a result of a pressure pulse in the hydraulic chamber ( 8 ). 
     
     
         8 . A method for adjusting a membrane pump having a pumping chamber;
 a pressure and a suction connection,   wherein the pressure and the suction connections are connected to the pumping chamber;   a hydraulic chamber,   wherein the pumping chamber and hydraulic chamber are separated from each other by a membrane,   wherein a pulsating working fluid pressure can be applied to the hydraulic chamber which can be filled with a working fluid,   wherein the membrane is moved between a first position in which the pumping chamber has a smaller volume, and a second position, in which the pumping chamber has a larger volume,   wherein the hydraulic chamber is connected to a working fluid reservoir via a leakage compensation valve;   wherein the membrane comprises a spring element having a first spring constant, which is designed such that it exerts a force on the membrane in the direction of the second position, characterized in that,   the spring constant is selected such that for the pressure p FV  applied to the working fluid by the spring element via the membrane it holds that: p FV >p A −p SO , where p A  is the atmospheric pressure and p SO  is the static pressure at the suction connection.   
     
     
         9 . A method according to  claim 8 , characterized in that the spring element is selected such that for the pressure p FV  applied by the spring element to the working fluid it holds that:
 p A >p FV >P A −P SO , where p A  is the atmospheric pressure.   
     
     
         10 . A method according to  claim 9 , characterized in that a membrane pump is used in which the suction connection is connected to the pumping chamber via a non-return valve, wherein the non-return valve is designed such that it opens when there is a pressure difference Δp SV  between the pressure at the suction connection and the pressure in the pumping chamber, wherein the spring element is selected such that for the pressure p FV  applied to the working fluid by the spring element it holds that: p A >p FV >p A −p SO +Δp SV .