Chemical liquid supplying apparatus

摘要

In a chemical liquid supplying apparatus 10a for discharging chemical liquid by expanding and contracting a pump chamber 16 which communicates with a chemical liquid inlet 21 and a chemical liquid outlet 22, the apparatus has a cylinder 12 in which a piston 31 is accommodated and reciprocally movable in an axial direction. A bellows 35 which is elastically deformable in the axial direction is mounted to a cylinder hole 30 between the tip of a connection rod 34 and the cylinder 12. On the inside of the bellows 35, an expanding/contracting chamber 37 is formed as a compartment between the connection rod 34 and the bellows 35, a pressure chamber 38 which communicates with the expanding/contracting chamber 37 is provided on the tip side of the piston 31, and an incompressible indirect medium 39 is enclosed in the expanding/contracting chamber 37 and the pressure chamber 38. The average effective diameter D2 of this bellows 35 is set so as to be smaller than the outer diameter D1 of a sliding surface 32 of the piston 31.

主权项

1. A chemical liquid supplying apparatus having a pump chamber which sucks chemical liquid from a chemical liquid supply source at the time of expansion of the pump chamber, and discharges the chemical liquid to a chemical liquid discharge unit at the time of contraction of the pump chamber, comprising:
a cylinder in which a piston is accommodated and reciprocally movable in an axial direction thereof, wherein the piston has a sliding surface that is in sliding contact with an inner surface of the cylinder, a connection rod is provided at a tip of the piston, and a pressure chamber in which an incompressible indirect medium is sealed is provided on a tip surface side of the piston; a bellows elastically deformable in the axial direction thereof and mounted between a tip of the connection rod and the cylinder, wherein an expanding/contracting chamber continuous from the pressure chamber is formed between the bellows and the connection rod, and an outer diameter of the sliding surface of the piston is larger than an average effective diameter of the bellows; driving means that are mechanically connected with the piston and configured to reciprocate the piston in the axial direction, wherein when the piston is moved in a forward direction, the bellows is expanded so as to contract the pump chamber, and when the piston is moved in a backward direction, the bellows is contracted so as to expand the pump chamber; and a sealing member for sealing any gap between the sliding surface of the piston and the inner surface of the cylinder, wherein the average effective diameter of the bellows is increased by the incompressible indirect medium which flows into the expanding/contracting chamber from the pressure chamber with the forward movement of the piston.