Chemical supply system with a pair of bellows connected in series for pumping a fluid

A chemical supply system comprising:

• a flexible tube made of an elastic material and elastically expandable or shrinkable in the radial direction;
• a flowpath through the bellows on a side of supply, which is connected between one end portion of said flexible tube and a chemical receiving portion and provided therein with an on-off valve on the side of supply;
• a flowpath through the bellows on a side of discharge, which is connected between the other portion of said flexible tube and a chemical discharging portion and provided therein with an on-off valve on the side of discharge;
• a bellows having a small bellows portion made of an elastic material connected in series to a large bellows portion made of an elastic material and larger in volume change per unit displacement value in the axial direction than said small bellows portion, disposed at the outside of said flexible tube and elastically deformable in an the axial direction;
• an incompressible medium enclosed in a space formed between said flexible tube and said bellows;
• and
• a driving means mechanically connected to the bellows for elastically deforming said bellows in the axial direction to shrink said small bellows portion and expand said large bellows portion to thereby elastically expand said flexible tube in the radial direction, while, for expanding said small bellows portion and shrinking said large bellows portion to elastically shrink said flexible tube in the radial direction.