A method and apparatus is provided for controlling the flow rate of a fluid that flows through a fluid path including a resiliently deformable portion.
A first roller (1) has a cutout (3) formed thereon on one side thereof, and a retainer (6) is arranged in parallel with the first roller. The resiliently deformable portion of the fluid path (14) is held between the first roller (1) and the retainer (6). The first roller (6) is rotatably supported by its rotary shaft (2). The first distance from the rotary shaft (2) to the outer wall (4) of the first roller (1) on the side facing opposite the resiliently deformable portion may be varied in response to the variation in the angle that occurs when the first roller (1) rotates about its rotary shaft (2). Thus, the second distance from the outer wall of the first roller on the side facing opposite the resiliently deformable portion to the retainer may be varied in response to the variation in the first distance, and the shape in cross section of the resiliently deformable portion may be varied according to the variation in the second distance. The flow rate of the fluid may be controlled by varying the shape in cross section of the resiliently deformable portion of the fluid path in this manner. The retainer may be replaced with the second roller (6) having the configuration symmetrical with the first roller and being rotatably supported.