Microdiaphragm pump

Abstract

A microdiaphragm pump having a diaphragm chamber in contact with one side of an intake valve and one side of a discharge valve. The microdiaphragm includes two valve plate sheets 12 , in each of which a valve plate 14 of one of an intake valve 26 and a discharge valve 28 and a flow path aperture 16 that provides a passage of the other valve are formed and which are laminated in directions that are opposite from each other; two valve seat sheets 18 , which are laminated to the laminate and in which valve seats 20 and valve stoppers 22 are formed; a base plate 32 ; a frame 34 ; a diaphragm 36 ; and a drive element 42 . The microdiaphragm pump has extremely small external dimensions and provides high productivity, high flow control accuracy, a smooth operation, large suction and discharge forces, and high reliability.

1 . A microdiaphragm pump which has a diaphragm chamber in contact with one side of an intake valve and a discharge valve, comprising:
 two valve plate sheets, in each of which a valve plate of one of the intake valve and the discharge valve and a flow path aperture that provides a flow path of the other valve are formed and which are laminated in such directions that the valve plates and the flow path apertures face each other;   two valve seat sheets, which are laminated to both surfaces of the laminate and in each of which a valve seat opposing the valve plate of the one valve plate sheet and a valve stopper opposing the valve plate of the other valve plate sheet are formed;   a base plate which is superposed on one of the valve seat sheets and which has two flow paths in communication with the intake valve and the discharge valve;   a frame which is superposed on the peripheral edge of the other valve seat sheet and which surrounds the intake valve and the discharge valve;   a diaphragm which is superposed on the frame to form a diaphragm chamber between the diaphragm and the valve seat sheet on which the frame has been superposed; and   a drive element retained on the diaphragm.   
     
     
         2 . The microdiaphragm pump according to  claim 1 , wherein the two valve plate sheets and the two valve seat sheets are formed of sheet metals, the two valve plate sheets are sandwiched by the two valve seat sheets, and the sheets are joined in a multilayered manner thereby to form a laminate. 
     
     
         3 . The microdiaphragm pump according to  claim 1 , wherein the valve plate is retained by a supporting arm that extends from an inner edge of a valve plate opening formed in the valve plate sheet toward the inside diameter, and opening diameters of the flow path aperture formed in the valve plate sheet and a flow path aperture which is formed in the base plate and which provides a flow path of the discharge valve are equal to an inside diameter of the valve plate opening. 
     
     
         4 . The microdiaphragm pump according to  claim 1 , wherein the valve plate and the flow path aperture of the valve plate sheet and the valve seat and the valve stopper of the valve seat sheet are processed by either etching or press stamping. 
     
     
         5 . The microdiaphragm pump according to  claim 2 , wherein the frame and the diaphragm are made of sheet metals and these are laminated to a surface on one side of the laminate formed in  claim 2 , and the base plate is laminated to a surface on the other side of the laminate, these layers being joined in a multilayered manner. 
     
     
         6 . The microdiaphragm pump according to  claim 1 , wherein the valve seats formed on the two valve seat sheets are provided with annular protrusions facing the valve plates to improve sealability relative to the valve plates. 
     
     
         7 . The microdiaphragm pump according to  claim 6 , wherein the annular protrusions formed on the two valve seat sheets are provided with DLC films to make the protrusions hard and smooth. 
     
     
         8 . The microdiaphragm pump according to  claim 7 , wherein the valve plates of the two valve plate sheets are subjected to stamping by pressing the valve plates against the annular protrusions of the valve seat sheets to improve close contact with the protrusions. 
     
     
         9 . The microdiaphragm pump according to  claim 8 , wherein the valve stopper of the valve seat sheet is provided with an annular portion facing the protrusion formed on the valve seat of the other valve seat sheet and a flow path divided in a circumferential direction around the annular portion, and the annular portion allows a stamping tool to be inserted therein. 
     
     
         10 . The microdiaphragm pump according to  claim 1 , wherein the drive element is a piezoelectric element attached to the diaphragm. 
     
     
         11 . The microdiaphragm pump according to  claim 10 , wherein a second frame, which surrounds the piezoelectric element, is fixed to the diaphragm.