Diaphragm pump

Abstract

A hydraulically driven diaphragm pump ( 1 ) comprises: a housing having a side ( 8 ) arranged to be connected with a membrane unit, a pumping element having a piston barrel ( 14 ) and a piston ( 17 ); and a fluid reservoir ( 10 ) wherein the pumping element is arranged to pump a working fluid from the fluid reservoir ( 10 ) during the delivery stroke. The diaphragm pump further comprises means ( 18,26 ) for applying a vacuum to the fluid reservoir ( 10 ) in order to improve the delivery accuracy and avoid malfunctioning of the pump. The diaphragm pump may further comprise a regulation chamber having adjusting means for adjusting the size of an active volume of the regulation chamber, thereby adjusting the pump delivery.

1 . Diaphragm pump comprising a housing, arranged to be connected with a membrane unit, said diaphragm pump also comprising a pump element having a piston barrel and a piston the diaphragm pump further comprising a fluid reservoir wherein the pump element is arranged to pump a pump fluid from the fluid reservoir and/or piston barrel during a first part of a piston stroke said diaphragm pump further comprising means for applying a vacuum to the fluid reservoir at least during part of a second part of a piston stroke. 
     
     
         2 . Diaphragm pump according to  claim 1  comprising a membrane unit. 
     
     
         3 . Diaphragm pump according to any of the preceding claims wherein the means for applying a vacuum is a vacuum pump element having a vacuum barrel and a vacuum piston. 
     
     
         4 . Diaphragm pump according to any of the preceding claims wherein there is direct fluid communication between fluid reservoir and the membrane unit at least when the piston is fully retracted. 
     
     
         5 . Diaphragm pump according to any of the preceding claims wherein the piston barrel comprises at least one inlet opening. 
     
     
         6 . Diaphragm pump according to any of the preceding claims wherein there is fluid communication from the hydraulic chamber through the piston barrel and inlet openings at least when the piston is fully retracted. 
     
     
         7 . Diaphragm pump according to any of the preceding claims wherein the fluid chamber and vacuum pump element is in fluid communication via at least one channel. 
     
     
         8 . Diaphragm pump according to any of the preceding claims wherein the fluid reservoir comprises a volume of fluid and a volume of gas during operation. 
     
     
         9 . Diaphragm pump according to any of the preceding claims wherein the channel is in fluid communication with the fluid volume 
     
     
         10 . Diaphragm pump according to any of the preceding claims wherein the piston of the pump element and a vacuum piston of the vacuum pump element are operated by common means. 
     
     
         11 . Diaphragm pump according to any of the preceding claims wherein the piston barrel and the vacuum barrel are connected end to end. 
     
     
         12 . Diaphragm pump according to any of the preceding claims wherein the piston of the pump element and the vacuum piston of the vacuum pump element are connected. 
     
     
         13 . Diaphragm pump according to any of the preceding claims wherein the piston of the pump element and the vacuum piston of the vacuum pump element are movable with respect to each other. 
     
     
         14 . Diaphragm pump according to any of the preceding claims wherein the vacuum piston partly extends over the piston of the pump element. 
     
     
         15 . Diaphragm pump according to any of the preceding claims wherein the diameter of the piston of the pump element is small than the diameter of the vacuum piston of the vacuum pump element. 
     
     
         16 . Diaphragm pump according to any of the preceding claims wherein at least the piston of the pump element is driven by a connecting rod and crank 
     
     
         17 . Diaphragm pump according to any of the preceding claims comprising a regulation chamber, wherein said regulation chamber is arranged with adjustment means for adjusting the size of an active volume of the regulation chamber and wherein the pump volume of the diaphragm pump is adjusted by the adjustment means. 
     
     
         18 . Diaphragm pump comprising a housing, arranged to be connected with a membrane unit, said diaphragm pump further comprising a pump element having a piston barrel and a piston, said diaphragm pump further comprising a fluid reservoir wherein the pump element is arranged to pump a pump fluid from the fluid reservoir during a first part of a piston stroke, said diaphragm pump further comprising a regulation chamber, wherein said regulation chamber is arranged with adjustment means for adjusting the size of an active volume of the regulation chamber and wherein the pump volume of the diaphragm pump is adjusted by the adjustment means. 
     
     
         19 . Diaphragm pump according to any of the proceeding claims comprising a membrane unit. 
     
     
         20 . Diaphragm pump according to any of the preceding claims wherein when connected to the membrane unit there is fluid communication between the membrane unit and the fluid reservoir and regulation chamber. 
     
     
         21 . Diaphragm pump according to any of the preceding claims wherein the adjusting means is a secondary piston moveable against a bias. 
     
     
         22 . Diaphragm pump according to any of the preceding claims comprising a lock for regulating the maximum stroke of the secondary piston to adjust the size of an effective volume of the regulation chamber. 
     
     
         23 . Diaphragm pump according to any of the preceding claims wherein there is direct fluid communication between fluid reservoir and the membrane unit at least when the piston is fully retracted. 
     
     
         24 . Diaphragm pump according to any of the preceding claims wherein the piston barrel comprises at least one inlet opening. 
     
     
         25 . Diaphragm pump according to any of the preceding claims wherein there is fluid communication from the hydraulic chamber through the piston barrel and inlet openings at least when the piston is fully retracted. 
     
     
         26 . Diaphragm pump according to any of the preceding claims comprising means for creating a vacuum in the fluid reservoir. 
     
     
         27 . Diaphragm pump according to any of the preceding claims wherein the means for creating a vacuum in the fluid chamber is a vacuum pump element. 
     
     
         28 . Diaphragm pump according to any of the preceding claims wherein the fluid chamber and vacuum pump element is in fluid communication via a channel. 
     
     
         29 . Diaphragm pump according to any of the preceding claims wherein the fluid reservoir comprises a volume of fluid and a volume of gas during operation. 
     
     
         30 . Diaphragm pump according to any of the preceding claims wherein the channel is in fluid communication with the fluid volume 
     
     
         31 . Diaphragm pump according to any of the preceding claims wherein the piston of the pump element and a piston of the vacuum pump element are operated by common means. 
     
     
         32 . Diaphragm pump according to any of the preceding claims wherein at least the piston of the pump element is driven by a connecting rod and crank 
     
     
         33 . Diaphragm pump according to any of the preceding claims comprising means for applying a vacuum to the fluid reservoir at least during part of a second part of a piston stroke 
     
     
         34 . Method of adjusting the pump volume of a diaphragm pump comprising the steps of
 providing a diaphragm pump with a housing, a membrane unit, means for moving the membrane to perform a pumping motion and adjusting the active volume of the regulation chamber thereby adjusting the degree of maximum displacement of the membrane.   
     
     
         35 . Method according to  claim 34  wherein the diaphragm pump is a diaphragm pump according to any of  claim 1 - 33 . 
     
     
         36 . Method of applying a vacuum to the fluid reservoir of a diaphragm pump comprising the steps of
 providing a diaphragm pump comprising a housing, a membrane unit, means for moving the membrane to perform a pumping motion, and means for providing a vacuum to the fluid reservoir   applying the vacuum to the fluid reservoir during the second part of a piston stroke of e pump piston during which the membrane unit is emptied from fluid.   
     
     
         37 . Method according to  claim 36  wherein the diaphragm pump is a diaphragm pump according to any of  claims 1 - 33 .