Method and apparatus for regulating fluid flow

Abstract

A low cost, mechanical method and apparatus for controlling the size of an internal orifice in a deformable tubing, particularly tubing of a viscoelastic material such as PVC used to administer intravenous fluids. A portion of the tubing is clamped to place a portion of the internal walls of the tubing into contact with one another at a plane of contact. The non-contacting portions of the tubing define at least one flow orifice. The contacting portions are then further compressed so that the wall thickness of the contacting tubes is reduced from its initial, unclamped thickness. The degree of this compression is such as to cause the adjacent tubing wall portions to curve away from the plane of contact, preferably with four point symmetry. This condition is also characterized by the stresses within the tube wall tending to expand or contract the orifice being generally in equilibrium within a brief period of time, typically less than five minutes, during which period the orifice usually expands slightly. In a preferred form, two side clamps face one another and are spaced along the tube to produce an orifice that defines a flow path transverse to the tubing. The clamping surfaces adjacent the orifice are preferably rounded or angled, opposed clamp members have abutting surfaces that limit the maximum displacement of the clamp, and an adjustment member is positioned to act on the outer surface of the opened orifice.