Rolling diaphragm pump

A rolling diaphragm pump comprising:

• a housing;
• a piston disposed so as to be slidable relative to an inner peripheral surface of the housing and reciprocatable in an axial direction of the housing;
• a rolling diaphragm having a movable portion disposed at one end portion in the axial direction of the piston and reciprocatable together with the piston, a fixed portion fixed to the housing, and a flexible connecting portion connecting the movable portion and the fixed portion to each other;
• a pump chamber defined by the rolling diaphragm at one side in the axial direction within the housing and into and from which a transport fluid is sucked and discharged by changing a volume of an interior of the pump chamber by deformation of the connecting portion due to reciprocation of the piston;
• a working fluid chamber defined by another end portion in the axial direction of the piston at another side in the axial direction within the housing and into and from which a working fluid is supplied and discharged, thereby causing the piston to reciprocate,
• wherein the piston includes a sliding portion slidable relative to the inner peripheral surface of the housing, a closely-contacted portion having an outer peripheral surface with which the deformed connecting portion can be brought into close contact, and a connection portion connecting the sliding portion and the closely-contacted portion to each other;
• a decompression chamber whose pressure is reduced to a predetermined pressure is defined, by the sliding portion and the connecting portion, between the inner peripheral surface of the housing and the outer peripheral surface of the piston;
• and
• a stopper projecting into the decompression chamber and configured to restrict movement of the sliding portion to the one side in the axial direction with respect to a predetermined position is integrally formed on the inner peripheral surface of the housing in the decompression chamber,
• wherein the stopper includes a ventilation port communicating with the decompression chamber and penetrating from an outer peripheral surface of the housing toward an inner peripheral surface of the stopper.