Apparatus for regulating fluid flow through plastic tubing

Abstract

The rate of flow of a fluid through plastic tubing is varied by clamping a portion of a circumferential section of the tube wall with sufficient force to fully close that part of the passage between the clamped wall portions, permitting fluid flow only through the resulting, remaining open cross-sectional area. Cold flow of the plastic material of the clamped portion of the tubing wall, such as might otherwise effect a change in the remaining cross-sectional flow area, is prevented or minimized by rigidly confining the clamped section. To adjustably vary the flow rate, the operative, passage-defining wall section of the tubing is varied by uniformly varying the ratio of the section of clamped tubing, and the remaining, operative wall portion of the tubing, or by deforming the operative wall portion.

I claim: 
     
       1. A flow regulator for controlling the rate of flow of fluid through a flexible plastic tubing comprising: a body formed with a passage to receive the tubing;   a clamping surface elongated in the direction of the tubing through said body and integrally formed in said body;   a clamping member mounted on said body for translation longitudinally of said body through a given distance above said clamping surface to unyieldingly define a clearance with respect to said clamping surface of substantially twice the nominal wall thickness of the tubing;   and an opening defining an elongated channel extending longitudinally in said clamping surface .[.to.]. .Iadd.and into .Iaddend.which a portion of the wall in the tubing is forced by said clamping member,   said body, said clamping surface, said clamping member, and said channel together defining a cross-sectional area smaller than the normal cross-sectional area included by the unclamped tubing and which varies between the ends of said channel as said clamping member is moved relative to said channel.   
     
     
       2. A flow regulator as in claim 1 in which: said channel includes planar opposite sidewalls that converge from a wide end of said channel towards an apex of said channel;   said wide end of said channel having a width, in the plane of said clamping surface, of less than the nominal width of the tubing.   
     
     
       3. A flow regulator as in claim 2 in which said sidewalls of said channel are divergent in a direction away from said clamping surface. 
     
     
       4. A flow regulator as in claim 2 in which said sidewalls of said channel are convergent in a direction away from said clamping surface. 
     
     
       5. A flow regulator as in claim 1 in which said channel has a floor that is angularly related to the longitudinal axis of said clamping surface. 
     
     
       6. A flow regulator for controlling the rate of flow of fluid through a flexible plastic tubing comprising: a body formed with a passage to receive the tubing;   a clamping surface integrally formed in said body;   a clamping member mounted on said body to unyieldably define a clearance with respect to said clamping surface of substantially twice the nominal wall thickness of the tubing;   and .[.an opening.]. .Iadd.a channel .Iaddend.in said clamping surface into which a portion of the wall in the tubing is forced by said clamping member;   said clamping surface, said clamping member and said .[.opening.]. .Iadd.channel .Iaddend.together defining a cross-sectional area smaller than the normal cross-sectional area included by the unclamped tubing,   said clamping member comprising a roller supported on track means formed in said body to clamp a wall portion of the tubing between a rim of said roller and said clamping surface;   said track means being parallel to said clamping surface to unyieldably constrain said roller to movement of said rim in a manner to maintain said clearance.   
     
     
       7. A flow regulator as in claim 6 in which: said channel is disposed symmetrically with respect to said clamping surface and with its longitudinal axis of symmetry within a plane including the median plane of said roller whereby to define a pair of clamping shoulders longitudinally adjacent to opposite sides of said channel against which wall portions of the tubing are clamped by axially opposite end portions of said rim of said roller while said channel receives a remaining unclamped portion of the tubing.   
     
     
       8. A flow regulator as in claim 7 in which: said body is formed with a longitudinally extending passage to receive the tubing and said roller;   said passage having a width less than one-half the normal circumference of the tubing;   said roller rim and said passage being adapted to rigidly confine substantially all wall portions of the tubing that are clamped by said roller against said clamping surface.   
     
     
       9. A flow regulator as in claim 8 in which the clearance between each of the axially opposite ends of said roller and said passage are less than one-half the wall thickness of the tubing.