Abstract: A piston 1 which is to be movably supported in a cylinder 11 of a pump 10 to be reciprocally driven is formed by a fluororesin so that it is not impaired by a corrosive liquid. A cylindrical outer peripheral portion 2 of the piston 1 has a thickness of 1 mm or less, and is flexible. The outer peripheral portion has a flange portion 7 in an open end portion via an approximately 180-degree folded-back portion 3. The flange portion 7 is attached to the cylinder 11. When the pump 10 is driven, the cylindrical outer peripheral portion 2 of the piston 1 smoothly rolls without producing deflections or bends in a gap between the outer peripheral face of a piston support member 15 and the inner peripheral face of the cylinder 11, while being in close contact with the two faces.

Abstract: A piston 1 which is to be movably supported in a cylinder 11 of a pump 10 to be reciprocally driven is formed by a fluororesin so that it is not impaired by a corrosive liquid. A cylindrical outer peripheral portion 2 of the piston 1 has a thickness of 1 mm or less, and is flexible. The outer peripheral portion has a flange portion 7 in an open end portion via an approximately 180-degree folded-back portion 3. The flange portion 7 is attached to the cylinder 11. When the pump 10 is driven, the cylindrical outer peripheral portion 2 of the piston 1 smoothly rolls without producing deflections or bends in a gap between the outer peripheral face of a piston support member 15 and the inner peripheral face of the cylinder 11, while being in close contact with the two faces.

Abstract: In a pump employing a bellows, individual members are formed from resins and pump components including a fitted assembly formed by fitting plural members with each other form a structure unit which is tightly inserted in an external cover and constrained on the opposite ends thereof for come off prevention. Thus, the distortion or deformation of the members during assembly is obviated and hence, a good sealing performance is achieved.

Abstract: The present invention relates to, among bellows pumps for transporting a liquid with using a bellows which axially extends and contracts, a so-called internal-liquid type bellows pump in which an air chamber is formed outside a bellows and a liquid to be transported is sucked into the bellows.

Abstract: In a pump employing a bellows, individual members are formed from resins and pump components including a fitted assembly formed by fitting plural members with each other form a structure unit which is tightly inserted in an external cover and constrained on the opposite ends thereof for come off prevention. Thus, the distortion or deformation of the members during assembly is obviated and hence, a good sealing performance is achieved.