Patent ID: 8398379
Filing Date: 2013-03-19
Classification: F04B

Abstract:
1. A chemical liquid supplying apparatus comprising: a cylinder formed with a cylinder bore; a piston assembled axially reciprocally into the cylinder bore; a seal member mounted in an annular groove formed in the cylinder, wherein an outer peripheral face of the piston slidably contacts the seal member, a pump case attached to an end face on which the cylinder bore opens, wherein the pump case has a liquid flow inlet and a liquid flow outlet; an elastically deformable partition membrane provided in a space formed between the pump case and the end face of the cylinder, wherein the partition membrane partitions the space into a driving chamber and a pump chamber, the driving chamber communicates with the cylinder bore, the driving chamber is filled with incompressible medium, the pump chamber communicates with the liquid flow inlet and the liquid flow outlet, and the pump chamber is filled with chemical liquid; driving means for reciprocating the piston to expand and contract the pump chamber via the incompressible medium in the driving chamber; and an elastically deformable diaphragm provided between the piston and the cylinder, the diaphragm having an elastically deformable portion, wherein the diaphragm forms a seal space separated by the piston and the seal member from the driving chamber, wherein the diaphragm deforms to absorb a volume change of the seal space caused by leakage of the incompressible medium between the piston and the cylinder, and to hold in the seal space incompressible medium leaked from the driving chamber as the piston continues to reciprocate.