Importance

Loading Importance Indicators...

Abstract

The present invention is an apparatus for restricting the flow of fluid. The apparatus defines a tubular member having a channel. The tubular member has a first portion in which the channel has a first cross sectional area. There is also a second portion for restricting the flow of fluid defined by a reproducible deformity in the channel such that the channel has a second cross sectional area which is smaller than the first cross sectional area of the first portion. The tubular member further defines a third portion having a third cross sectional area which is greater than the second cross sectional area of the second portion. All of the cross sectional dimensions of the second and third portions are disposed within a cylindrical envelope having a diameter equal to the diameter of the first portion and extending therefrom. The tubular member is comprised of a material having sufficient rigidity to maintain a preferred reproducible permanent deformity in the channel. Portion has an essentially constant outside diameter and wherein all cross sectional dimensions of the tubular member are less than or equal to the diameter of the first portion and all of the cross sectional dimensions of the second and third portions are disposed within a cylindrical envelope having a diameter equal to the diameter of the first portion and extending therefrom. Preferably, the deformity is defined by a spherical indentation and the tubular member is comprised of stainless steel. The present invention is also a method of forming a fluid restrictor comprising the steps of first placing a tubular member having a channel and a predetermined outside diameter into a fixed relationship with a deforming apparatus. Then, there is the step of deforming the tubular member in a reproducible manner such that a cross sectional area of the channel is decreased so flow of fluid through the channel is restricted a desired amount. The deforming step does not cause the tubular member to flare and all of the cross sectional dimensions of the second and third portions disposed within a cylindrical envelope having a diameter equal to the diameter of the first portion and extending therefrom. Preferably, the deforming step includes the step of forcing a shaping element of the deforming apparatus against the tubular member. Alternatively, the deforming apparatus can be used to adjust the magnitude of fluid restriction during operation of the fluid restrictor.

Loading the Abstract Image...

First Claim