摘要 |
A part of an air tube having flexibility is surrounded by a casing, and the air tube inside the easing is pushed for deformation at a nearly right angle against the pipe axis by a male screw screwed to a female screw of the casing to change a cross sectional area of a passage inside the air tube. A first casing part and a second casing part are overlapped with each other, and openably connected by a hinge, and the overlap state of both the casing parts and is maintained by engaging a claw part with the hole. Opposite surfaces and of both the casing parts and are provided with support grooves and for supporting the outer peripheral surface of the air tube. |