FLUID DEVICE WITH BELLOWS

It is an object of the invention to, even in the case where transported liquid containing a sedimenting material such as slurry is used, prevent the sedimenting material from stagnating and collecting inside a suction check valve and a discharge check valve. In order to attain the object, a bellows 7 that is extendingly and contractingly deformable in the axial direction is placed in a pump body 1 with setting the axis B of the bellows vertical so as to be driven to perform extending and contracting deformation, and form a liquid chamber 9 inside the bellows 7. A suction port 18 and a discharge port 19 are formed in an inner bottom face 4a of the pump body 1 facing the liquid chamber 9. Liquid is sucked from the suction port 18 into the liquid chamber 9 by extension of the bellows 7, and the liquid in the liquid chamber 9 is discharged from the discharge port 19 by contraction of the bellows 7. In each of a suction ball type check valve 20 disposed in the suction port 18, and a discharge ball type check valve 21 disposed in an outflow passage 6 which communicates with the discharge port 19, a cylindrical valve casing 201 or 220 is disposed with setting the axis D or G vertical, and ball valve elements 202 or 221 in the valve casing 201 or 220 are caused by their own weight to be closely contacted with valve seat 211 (213) or 230 (232), thereby preventing liquid from reversely flowing.