Bellows pump

A bellows pump comprising:

• a pump head;
• a pair of bottom-closed cylindrical bellows provided on respective opposite sides of the pump head with opening sides of the pair of bellows being opposed to one another, each of the pair of bellows forming a pump chamber therein to extend and contract in an axial direction;
• a pair of bottom-closed cylinders attached to the pump head with opening portions of the cylinders being opposed to one another, the pair of cylinders being disposed coaxially to the pair of bellows to contain the respective bellows therein, the pair of cylinders forming operation chambers between the pair of cylinders and the pair of bellows;
• a pair of pump shafts passing through respective bottoms of the pair of cylinders slidably in an airtight manner along a central axis of the pair of cylinders, the pair of pump shafts having first ends joined to respective bottoms of the pair of bellows;
• a joint shaft joining second ends of the pair of pump shafts movably in the axial direction;
• and
• a valve unit attached to the pump head in the pump chambers, the valve unit introducing a fluid to be transferred from a suction opening of the fluid to be transferred to the pump chamber and introducing the fluid to be transferred from the pump chamber to a discharge opening of the fluid to be transferred, wherein
• the pair of bellows is extended and contracted by introducing a working fluid into the operation chambers and discharging the working fluid from the operation chambers, thus transferring the fluid to be transferred,
• each of the pair of bellows is configured by alternately forming mountain portions and valley portions along the axial direction and having, on a predetermined position in the axial direction where a valley portion is formed, an annular ring portion extending in a radial direction from the valley portion to a mountain portion, the radial direction being perpendicular to the axial direction,
• each of the bellows further including at least one additional annular ring portion, the at least one additional annular ring portion extending in the radial direction from another valley portion to another mountain portion and being formed at a predetermined interval relative to the annular ring portion in the axial direction, and
• each of the annular ring portion and the at least one additional annular ring portion being integrally formed as a single piece with the valley portions and the mountain portions of the bellows.