Liquid supply device

Abstract

A liquid supply device causes a tubephragm 15 as a first flexible member to expand to inject a liquid into a pump chamber 16, and causes the tubephragm 15 to contract to discharge the liquid in the pump chamber 16 to an outside, the device including: a medium accommodation case 28 having a bellows 31 as a second flexible member, the bellows partitioning a medium accommodation chamber 32 communicating with a pump accommodation chamber 17 and an air chamber 33; a drive mechanism 27 provided with a rod 44 a; an electric motor 46 as a drive member for causing the rod 44 a to reciprocate axially; and a pressure adjustment mechanism 60 for reducing a pressure in the air chamber 33 when the bellows 31 is contracted to expand the tubephragm 15 via a liquid medium M.

1 . A liquid supply device arranged in a pump case, having a first flexible member for partitioning a pump chamber and a pump accommodation chamber, increasing a volume of the pump chamber to inject a liquid into the pump chamber, and reducing the volume of the pump chamber to discharge the liquid in the pump chamber to an outside, the liquid supply device comprising:
 a media accommodation case having a second flexible member for partitioning a medium accommodation chamber communicating with the pump accommodation chamber and an air chamber;   a liquid medium filled in the pump accommodation chamber and the medium accommodation chamber;   a drive member reciprocating a rod in a discharge direction of supplying the liquid medium from the medium accommodation chamber to the pump accommodation chamber and an injection direction of returning the liquid medium from the pump accommodation chamber to the medium accommodation chamber, the rod being attached to the second flexible member; and   a pressure adjustment mechanism for reducing a pressure of the air chamber when the rod is driven in the injection direction to reduce the volume of the air chamber.   
     
     
         2 . The liquid supply device according to  claim 1 ,
 wherein the pressure adjustment mechanism has:
 a cylinder in which a pressure adjustment chamber communicating with the air chamber is formed; and a pressure adjustment piston reciprocably accommodated axially in the cylinder, and 
   the pressure adjustment piston:
 sucks air in the air chamber into the pressure adjustment chamber when the rod is driven in the injection direction to reduce the volume of the air chamber; and 
 supplies air in the pressure adjustment chamber into the air chamber when the rod is driven in the discharge direction to increase the volume of the air chamber. 
   
     
     
         3 . The liquid supply device according to  claim 2 ,
 wherein the pressure adjustment piston is provided with a positive pressure relief valve for discharging the air in the pressure adjustment chamber to the outside when the pressure in the pressure adjustment chamber becomes higher than an allowable positive pressure, and   the pressure adjustment piston is provided with a negative pressure relief valve for supplying the air in the pressure adjustment chamber when the pressure in the pressure adjustment chamber becomes lower than an allowable negative pressure.   
     
     
         4 . The liquid supply device according to  claim 2 ,
 wherein the pressure adjustment piston is provided on the rod, and the rod causes the second flexible member and the pressure adjustment piston to reciprocate synchronously.   
     
     
         5 . The liquid supply device according to  claim 1 ,
 wherein the pressure adjustment mechanism is a vacuum ejector including:
 an air supply port communicating with an air supply source; a diffuser to which compressed air supplied from the air supply port is injected; and a suction port communicating with the diffuser and communicating with the air chamber. 
   
     
     
         6 . The liquid supply device according to  claim 5 ,
 wherein an on-off valve is provided in an air supply flow path between the air supply port and a supply source of compressed air, and when the rod is moved in the injection direction to return the liquid medium from the pump accommodation chamber to the medium accommodation chamber, the on-off valve opens the air supply flow path.   
     
     
         7 . The liquid supply device according to  claim 5 , further comprising:
 an on-off valve provided in an air supply flow path between the air supply port and a supply source of compressed air; and a regulator provided between the on-off valve and the air supply port and adjusting the pressure of the compressed air supplied to the air supply port,   wherein the on-off valve reciprocating the rod with on a state of opening the air supply flow path.   
     
     
         8 . The liquid supply device according to  claim 1 ,
 wherein the pressure adjustment mechanism is a vacuum pump having a vacuum flow path communicated with the air chamber.   
     
     
         9 . The liquid supply device according to  claim 8 ,
 wherein an on-off valve is provided in the vacuum flow path, and when the rod is moved in the injection direction to return the liquid medium from the pump accommodation chamber to the medium accommodation chamber, the on-off valve opens a vacuum flow path.   
     
     
         10 . The liquid supply device according to  claim 1 ,
 wherein the first flexible member is any of: a tubephragm elastically deformable in a radial direction, the pump chamber being provided inside, and the pump accommodation chamber being provided outside; a bellows elastically deformable in an axial direction, the pump chamber being provided inside, and the pump chamber being provided outside; and a diaphragm elastically deformable in the axial direction, the pump chamber being formed outside, and the pump accommodation chamber being formed inside.   
     
     
         11 . The liquid supply device according to  claim 1 ,
 wherein the second flexible member is any one: a bellows elastically deformable in the axial direction, the air chamber being provided inside, the medium accommodation chamber being provided outside; or a diaphragm elastically deformable in the axial direction, the medium accommodation chamber being formed outside, and the air chamber being formed inside.   
     
     
         12 . A liquid supply device arranged in a pump case, having a flexible member for partitioning a pump chamber and an air chamber, increasing a volume of the pump chamber to inject a liquid into the pump chamber, and reducing the volume of the pump chamber to discharge the liquid in the pump chamber to an outside, the liquid supply device comprising:
 a drive member for reciprocating a rod between a discharge direction of discharging the liquid in the pump chamber to the outside and an injection direction of injecting the liquid into the pump chamber, the rod being attached to the flexible member; and   a pressure adjustment mechanism for reducing a pressure of the air chamber when the rod is moved in the injection direction to reduce the volume of the air chamber.   
     
     
         13 . The liquid supply device according to  claim 12 ,
 wherein the flexible member is any one of: a bellows elastically deformable in an axial direction, the pump chamber being provided outside, and the air chamber being provided inside; or a diaphragm elastically deformable in the axial direction, the pump chamber being formed outside, and the air chamber being formed inside.