Patent ID: 7806668
Filing Date: 2010-10-05
Classification: F04B

Abstract:
1. A flexible tube for supplying a chemical liquid, which is assembled in a chemical liquid supply apparatus and partitions an internal expansion/shrinkage chamber inside the tube and an external pressurizing chamber outside the tube, said tube comprising: a tubular inlet side end fixed to the chemical liquid supply apparatus, a tubular outlet side end fixed to the chemical liquid supply apparatus, and an elastic deformation portion between the inlet and outlet side fixed ends, the inlet and outlet side fixed ends and the elastic deformation portion forming principal parts of the flexible tube, and the flexible tube being formed of a resin; and the elastic deformation portion in an undeformed condition including convex arc portions whose deformation centers are three apices spaced apart at approximately regular intervals in a circumferential direction of the flexible tube and which are curved in convex shapes so as to have a smaller curvature radius than that of a virtual circle tangent to the apices, and concave arc portions located inwardly of and between the convex arc portions and joined consecutively between the respective convex arc portions to form a closed deformable shape, wherein an increase in the volume of the pressurizing chamber causes a shrinking deformation of the elastic deformation portion from its undeformed condition to expel fluid from the internal chamber, the shrinking deformation being characterized in that the convex arc portions elastically deform in the circumferential direction from the apices as centers without significant radial displacement of the apices, and the concave arc portions elastically deform in a radial direction, and thereafter a decrease in the volume of the pressurizing chamber allows the elastic deformation portion to return to its undeformed condition, by the elasticity of the flexible tube itself, thereby ingesting fluid into the internal chamber.