Piston diaphragm pump

Abstract

A diaphragm piston pump with a leakage control has a control unit in the area of the diaphragm, which can be activated by the pressure of the diaphragm during the suction stroke, wherein the control unit is hydraulically connected to a leakage replenishing valve, via which the sealing liquid can be discharged into the piston chamber of the diaphragm piston pump. The position of the diaphragm is not transmitted mechanically via a control rod and a rocker arm, but hydraulically. This makes it possible to achieve efficient leakage control without the spatial and mechanical restrictions of the prior art.

1 . A diaphragm piston pump comprising a leakage control, wherein a control unit ( 1 ) is provided in the region of the diaphragm, which can be activated by the pressure of the diaphragm ( 8 ,  9 ) during the suction stroke, wherein the control unit ( 1 ) is hydraulically connected to a leakage replenishing valve ( 2 ), via which the sealing liquid ( 15 ) can be discharged into the piston chamber of the diaphragm piston pump, wherein the supplementary leakage valve ( 2 ) is only effective when a leakage valve ( 30 ) is activated, wherein the leakage valve ( 30 ) can be activated hydraulically. 
     
     
         2 . The diaphragm piston pump according to  claim 1 , wherein the control unit ( 1 ) is arranged between the piston ( 10 ) of the diaphragm piston pump and the secondary hose diaphragm ( 9 ), wherein a control disc ( 20 ) which can be acted upon by the secondary hose diaphragm ( 9 ) is guided by a control rod ( 23 ) so as to be displaceable in the longitudinal direction against a restoring force, wherein the control rod ( 23 ) comprises an activating piston ( 26 ) for the hydraulic connection with the leakage valve ( 30 ). 
     
     
         3 . The diaphragm piston pump according to  claim 1 , wherein the leakage valve ( 30 ) comprises a control piston ( 34 ), on the pressurization of which the leakage valve ( 30 ) opens, so that the applied pressure in the hydraulic connection acts on an replenishing valve ( 31 ) via a connecting channel ( 36 ) in order to open said valve against a restoring force when a pressure lower than the opening pressure of the replenishing valve ( 31 ) is applied. 
     
     
         4 . The diaphragm piston pump according to  claim 2 , wherein the leakage valve ( 30 ) comprises a control piston ( 34 ), on the pressurization of which the leakage valve ( 30 ) opens, so that the applied pressure in the hydraulic connection acts on an replenishing valve ( 31 ) via a connecting channel ( 36 ) in order to open said valve against a restoring force when a pressure lower than the opening pressure of the replenishing valve ( 31 ) is applied.