Pump for Supplying Chemical Liquids

Abstract

An opening 22 d of a supply/withdrawal passage 22 b is positioned at the center part of the internal wall surface 22 c of the operating chamber 26 (concave area 22 a ), and a cross-shaped venting groove 22 e extending from the opening 22 d of the passage 22 b to the periphery of the wall surface 22 c is formed in the wall surface 22 c . Thus, an operating air in the chamber 26 is discharged (sucked) through the passage 22 b during drawing in the chemical liquid. Since the opening 22 d communicates with the venting groove 22 e extending to the periphery of the chamber 26 , if the center of the diaphragm 23 covers the opening 22 d first, the operating air in the chamber 26 can be continuously evacuated (drew out) from the venting groove 22 e positioned on the outside of the center part which first comes into contact with the opening 22 d

1 . In a pump for supplying chemical liquids in which a pump chamber and an operating chamber are divided by means of a diaphragm comprised of a flexible film, the diaphragm deforms toward the pump chamber when the interior of the pump chamber is pressurized using an operating gas, thereby discharging the chemical liquid that has been supplied into the pump chamber; and when the interior of the operating chamber reaches a negative pressure because of the withdrawal of the operating gas or when the interior of the operating chamber is opened to the surrounding atmosphere, the diaphragm deforms toward the operating chamber, thereby drawing a chemical liquid into the pump chamber, and a supply/withdrawal passage for supplying the operating gas to or withdrawing same from the operating chamber is formed in the pump housing, and an opening of the supply/withdrawal passage is provided in part of the internal wall surface of the operating chamber, and a venting groove that extends from the opening of the supply/withdrawal passage to the periphery of the internal wall surface is formed on the internal wall surface of the operating chamber.  
     
     
         2 . The pump for supplying chemical liquids according to  claim 1 , wherein the internal wall surface of the operating chamber is circular in shape, and the opening of the supply/withdrawal passage is positioned in the center of the internal wall surface of the operating chamber.  
     
     
         3 . The pump for supplying chemical liquids according to  claim 1 , wherein the opening of the supply/withdrawal passage is positioned in the center of the internal wall surface of the operating chamber with the internal wall formed symmetrically from its center; and 
 the venting groove is formed to be symmetrical, with the center of the opening of the supply/withdrawal passage at its center, in correspondence with the internal wall surface of the operating chamber.    
     
     
         4 . The pump for supplying chemical liquids according to  claim 1 , wherein the venting groove is linear in shape.  
     
     
         5 . The pump for supplying chemical liquids according to  claim 1 , wherein the venting groove is configured from continuous concave areas obtained by forming a rough internal wall surface in the operating chamber.  
     
     
         6 . The pump for supplying chemical liquids according to any of  claim 5 , wherein roughening of the internal wall surface of the operating chamber is applied to the entire internal wall surface.  
     
     
         7 . The pump for supplying chemical liquids according to  claim 1 , wherein the pump housing is formed to be thin in the deformation direction of the diaphragm.  
     
     
         8 . The pump for supplying chemical liquids according to  claim 2 , wherein the venting groove is linear in shape.  
     
     
         9 . The pump for supplying chemical liquids according to  claim 2 , wherein the venting groove is configured from continuous concave areas obtained by forming a rough internal wall surface in the operating chamber.  
     
     
         10 . The pump for supplying chemical liquids according to  claim 9 , wherein roughening of the internal wall surface of the operating chamber is applied to the entire internal wall surface.