Fluid flow control means

Claim 1

An extruded flexible plastic tubing generally circular in cross section for conveying fluids including a limited axial portion having a generally curved noncircular internal bore, said tubing being initially circular and said limited axial portion being crimped along opposite sides thereof and permanently deformed so that opposed axially extending portions of said bore wall have adjacent surfaces thereof brought into juxtaposition to one another to form a bore defining in cross section a flattened oval having opposed sharply pointed feathered ends falling substantially on the major axis of the oval and opposed smooth curved surfaces falling on the minor axis of the oval, the outer surfaces of said limited axial portion being generally curvilinear in relaxed condition, said tubing when subjected to sufficient force along said minor axis collapsing to totally close said bore and feathered ends of said oval bore eliminating cold flow in sAid limited axial portion.

Claim 4

A device for controlling the flow of fluids including a small, round, flexible plastic tubing for conveying the fluids having a limited axial portion provided with a generally curved noncircular internal bore, said tubing being initially circular and said limited axial portion being crimped along opposite sides thereof opposed axially extending portions of said bore wall having adjacent surfaces thereof brought into permanent juxtaposition to one another to form a limited axial bore defining in cross section a flattened oval having opposed sharply pointed feathered ends falling substantially on the major dimension of the oval and opposed smooth curved surfaces falling on the minor dimension of the oval, clamp means for clamping the flexible tubing and at least one orienting means spaced from said clamp means having a complementary configuration for surrounding and capturing a segment of said limited axial portion of the tubing in a predetermined relationship with the minor axis of the tubing bore being positively oriented relative to said clamp means whereby said clamp means can apply a transverse force to incrementally collapse the bore and reduce the available passageway through said tubing from a maximum until the tubing bore is completely closed, said crimped limited axial portion of said tubing obviating the normal cold flow inherent in the round portion of said plastic tubing.

Claim 5

A device for controlling the flow of fluids including a small, round, flexible plastic tubing for conveying the fluids having a limited axial portion provided with a generally curved noncircular internal bore, said tubing being initially circular and said limited axial portion being crimped along opposite sides thereof opposed axially extending portions of said bore wall having adjacent surfaces thereof brought into permanent juxtaposition to one another to form a limited axial bore defining in cross section a flattened oval having opposed sharply pointed feathered ends falling substantially on the major dimension of the oval and opposed smooth curved surfaces falling on the minor dimension of the oval, clamp means for clamping the flexible tubing and at least one orienting means spaced from said clamp means having a complementary configuration for surrounding and capturing a segment of said limited axial portion of the tubing in a predetermined relationship with the minor axis of the tubing bore being positively oriented relative to said clamp means whereby said clamp means can apply a transverse force to incrementally collapse the bore and reduce the available passageway through said tubing from a maximum until the tubing bore is completely closed, said crimped limited axial portion of said tubing obviating the normal cold flow inherent in the round portion of said plastic tubing.