Abstract: 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.
Abstract: 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.