Diaphragm pump with a functionally safe diaphragm position control

Abstract

The present invention relates to diaphragm pump ( 1 ) having a delivery chamber ( 3 ) and a working chamber ( 5 ), wherein the working chamber can be or is filled with a hydraulic fluid and is operatively connected to a pressure generating device in order to apply an oscillating pressure to the hydraulic fluid, further comprising a diaphragm ( 11 ) having at least one diaphragm layer ( 13 ) and a diaphragm core ( 15 ), which separates the delivery chamber ( 3 ) and the working chamber ( 5 ) from each other, wherein the diaphragm ( 11 ) is or can be operatively connected to a diaphragm return device ( 17 ) comprising a pull rod ( 19 ), which applies or can apply a return force on the diaphragm ( 11 ) in the direction of the suction stroke position, and further comprising a storage chamber ( 21 ) for holding the hydraulic fluid, and wherein the working chamber ( 5 ) and the storage chamber ( 21 ) are connected to each other by means of a return flow channel ( 25 ) closed by means of a closure element ( 23, 23 ′), and wherein the closure element ( 23, 23 ′) is operatively connected to the diaphragm core ( 15 ) and the diaphragm return device ( 17 ), so that the return force and a pressure force counteracting the return force as a result of the fluid pressure in the working chamber ( 5 ) act on the closure element ( 23, 23 ′), and wherein, when a predetermined triggering force is exceeded as a sum of the return force and the pressure force on the closure element ( 23, 23 ′), the return flow channel ( 25 ) is opened.

1 . A diaphragm pump ( 1 ) having a delivery chamber ( 3 ) and a working chamber ( 5 ), wherein the delivery chamber ( 3 ) comprises a pressure connection ( 7 ) and a suction connection ( 9 ), and wherein the working chamber can be or is filled with a hydraulic fluid and is operatively connected to a pressure generating device in order to apply an oscillating pressure to the hydraulic fluid, further comprising a diaphragm ( 11 ) having at least one diaphragm layer ( 13 ) and a diaphragm core ( 15 ), which separates the delivery chamber ( 3 ) and the working chamber ( 5 ) from each other and which can be transferred from a pressure stroke position into a suction stroke position and back again, wherein the volume of the delivery chamber ( 3 ) in the pressure stroke position of the diaphragm ( 11 ) is smaller than in the suction stroke position, and wherein the diaphragm ( 11 ) is or can be operatively connected to a diaphragm return device ( 17 ) comprising a pull rod ( 19 ), which applies or can apply a return force on the diaphragm ( 11 ) in the direction of the suction stroke position, and further comprising a storage chamber ( 21 ) for holding the hydraulic fluid, and wherein the working chamber ( 5 ) and the storage chamber ( 21 ) are connected to each other by means of a return flow channel ( 25 ) closed by means of a closure element ( 23 ,  23 ′) [ 23 ′ is not yet found in the figures], wherein the closure element ( 23 ,  23 ′) is operatively connected to the diaphragm core ( 15 ) and the diaphragm return device ( 17 ), so that the return force and a pressure force counteracting the return force as a result of the fluid pressure in the working chamber ( 5 ) act on the closure element ( 23 ,  23 ′), and wherein, when a predetermined triggering force is exceeded as a sum of the return force and the pressure force on the closure element ( 23 ,  23 ′), the return flow channel ( 25 ) is opened, wherein diaphragm core ( 15 ) and pull rod ( 19 ) are detachably connected to each other, wherein, when the diaphragm core ( 15 ) and pull rod ( 19 ) are connected, the return flow channel ( 25 ) is closed, and when they are not connected, the return flow channel ( 25 ) is opened. 
     
     
         2 . The diaphragm pump as claimed in  claim 1 , wherein, in the event of a deflection of the diaphragm ( 11 ) away from the suction stroke position beyond the pressure stroke position, the closure element ( 23 ,  23 ′) and the return flow channel ( 25 ) are opened. 
     
     
         3 . The diaphragm pump as claimed in  claim 1 , wherein the return flow channel ( 25 ) extends partly in the diaphragm return device ( 17 ). 
     
     
         4 . (canceled) 
     
     
         5 . The diaphragm pump as claimed in  claim 1 , wherein the closure element ( 23 ,  23 ′) is formed by the diaphragm core ( 15 ). 
     
     
         6 . The diaphragm pump as claimed in  claim 1 , wherein the return flow channel ( 25 ) extends partly in the pull rod ( 19 ) of the diaphragm return device ( 17 ). 
     
     
         7 . The diaphragm pump as claimed in  claim 1 , wherein the closure element ( 23 ,  23 ′) comprises a magnet ( 27 ) and/or is operatively connected thereto, wherein direction and intensity of the magnetic force correspond to the predetermined triggering force and, when the triggering force is exceeded, the return flow channel ( 25 ) is opened. 
     
     
         8 . The diaphragm pump as claimed in  claim 1 , wherein the closure element ( 23 ,  23 ′) comprises an intended breaking point ( 33 ) as overload protection, which resists the triggering force and, when the triggering force is exceeded, breaks and the return flow channel ( 25 ) is opened. 
     
     
         9 . The diaphragm pump as claimed in  claim 1 , wherein the working chamber is arranged in a housing, wherein the return flow channel ( 25 ) extends partly through the housing in the region of the pull rod ( 19 ). 
     
     
         10 . The diaphragm pump as claimed in  claim 9 , wherein the diaphragm return device ( 17 ) is guided partly through a region of the housing that is formed as a guide section ( 35 ), wherein the return flow channel ( 25 ) has on its side facing the diaphragm return device ( 17 ) an elongated connecting section ( 37 ) along the deflection of the diaphragm return device ( 17 ), so that, irrespective of the deflection position of the diaphragm return device ( 17 ), the section of the return flow channel ( 25 ) that is located in the diaphragm return device ( 17 ) and the section of the return flow channel ( 25 ) that is located in the housing are operatively connected. 
     
     
         11 . The diaphragm pump as claimed in  claim 1 , wherein the pull rod ( 19 ) is operatively connected to a spring element ( 39 ), so that the diaphragm ( 11 ) is spring-loaded in the direction of the suction stroke. 
     
     
         12 . The diaphragm pump as claimed in  claim 1 , wherein the deflection of the pull rod ( 19 ) is limited by means of a fixed stop, so that the pull rod ( 19 ) cannot be moved from the suction stroke position beyond the pressure stroke position or a pre-determined position further removed from the suction stroke position than the pressure stroke position. 
     
     
         13 . The diaphragm pump as claimed in  claim 1 , wherein the working chamber ( 5 ) and the storage chamber ( 21 ) are connected to each other via a return flow channel ( 43 ) closed by a further closure element ( 41 ), wherein the further closure element ( 41 ) is connected to the pull rod ( 19 ) so as to be movable relative to the latter, so that the further closure element ( 41 ) can be transferred from a closed position into an open position and back, and wherein the further closure element ( 41 ) comprises a force generating element ( 45 ) and/or is operatively connected to the latter, which locks the further closure element ( 41 ) in the closed position, and wherein the further closure element ( 21 ) is transferred into the open position and the further return flow channel ( 43 ) is opened when it is true of the pressure difference between the pressure in the storage chamber p 2  and the pressure in the working chamber p 1  that p 2 −p 1 >a, where a is a predetermined pressure. 
     
     
         14 . The diaphragm pump as claimed in  claim 12 , wherein the further return flow channel ( 43 ) extends partly in the diaphragm return device ( 17 ), in particular in the pull rod ( 19 ), and wherein the further return flow channel ( 43 ) is preferably connected to the return flow channel ( 25 ).