FLUID FLOW CONTROL SYSTEM HAVING CAPILLARY FLUID FLOW RESTRICTOR

• US 20080257410A1
• Filed: 04/20/2007
• Published: 10/23/2008
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Original Assignee: Cardinal Health 303 Incorporated (Cardinal Health, Inc.)
• Inventors: WALBORN, JONATHAN
• Granted Patent: US 7,892,213 B2
• Time in Patent Office: Days
• US Class Current: 137/1
• CPC Class Codes: A61M 5/141 with capillaries for restricting fluid flow
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/16804 Flow controllers
• CPC Class Codes: A61M 5/16877 Adjusting flow; Devices for setting a flow rate
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/85978 With pump

Abstract

A fluid flow rate control system and method comprises a capillary tube having a proximal end that projects into a chamber with a cross-sectional area that is larger than or equal to the fluid supply tube'"'"'s cross-sectional area. The inner cross-sectional area of the capillary tube is configured less than the inner cross-sectional area of the chamber. The chamber has a volume large enough to slow the fluid conducted to it by the upstream fluid line to permit contaminants to fall out of solution. In another aspect, a sleeve is used to mount the capillary tube into the chamber. The sleeve provides a mounting surface for tube segments from the pump and downstream of the capillary restrictor.

Claims

1. A fluid flow restrictor for regulating the flow rate of fluid through a fluid supply tube, the supply tube having a distal end and having an internal fluid passageway with a supply tube inner cross-sectional area, the restrictor comprising:

a chamber having a distal end and a proximal end, the proximal end of which is in fluid communication with the distal end of the supply tube wherein fluid from the supply tube flows into the chamber through the proximal end of the chamber, the chamber having a chamber length and a chamber inner cross-sectional area that is larger than the supply tube inner cross-sectional area; and

a restrictor tube having an inner cross-sectional area that is smaller than the supply tube inner cross-sectional area and smaller than the chamber inner cross-sectional area, said restrictor tube having a length, wherein the restrictor tube length and the restrictor tube inner cross-sectional area are configured to result in a desired flow rate, the restrictor tube having a proximal end extending into the chamber from the distal end of the chamber.

2. The fluid flow restrictor of claim 1 wherein the restrictor tube is surrounded by a sleeve over less than the entire length of the restrictor tube, wherein the sleeve mounts the restrictor tube in the chamber such that the proximal end of the restrictor tube projects into the chamber.

3. The fluid flow restrictor of claim 2, further comprising a housing surrounding the sleeve and coupled with the distal end of the fluid supply tube forming the chamber between the distal end of the fluid supply tube and the sleeve.

4. The fluid flow restrictor of claim 1 wherein the supply tube has the same cross-sectional area as the chamber.

5. The fluid flow restrictor of claim 1 wherein the inner cross-sectional area of the restrictor tube is much less than the inner cross-sectional area of the chamber.

6. The fluid flow restrictor of claim 1 wherein the restrictor tube has a distal end that is in fluid communication with a distal segment of a tube that conducts fluid flowing through the restrictor tube to a downstream location at the flow rate controlled by the restrictor tube.

7. The fluid flow restrictor of claim 1 wherein the restrictor tube is surrounded by a sleeve over less than the entire length of the restrictor tube, wherein the sleeve mounts the restrictor tube such that the proximal end of the restrictor tube projects into the chamber, the sleeve having a radially-outwardly extending mounting flange;

a first housing surrounding the sleeve and interconnecting with the distal end of the fluid supply tube forming the chamber between the distal end of the fluid supply tube and the sleeve wherein all flow through the chamber proceeds through the restrictor tube;

a second housing surrounding the sleeve and interconnecting with a downstream segment of fluid tube into which the restrictor tube feeds fluid; and

the first and second housings mounted over the sleeve and abutting the mounting flange.

8. An infusion system comprising:

a pump;

a supply tube segment in fluid communication with the pump to conduct fluid from the pump, the supply tube segment having a distal end and a supply tube inner diameter; and

a capillary flow restrictor in fluid communication with the distal end of the supply tube segment for receiving fluid from the pump and controlling the flow rate of that fluid, the capillary flow restrictor comprising;

a housing connected with the supply tube segment for receiving fluid from the pump, the housing having a proximal end;

a sleeve disposed within the housing and having a proximal end, the sleeve disposed so that the proximal end of the sleeve is not coincident with the proximal end of the housing, thereby forming a chamber having an inner chamber cross sectional area; and

a capillary tube mounted partially within the sleeve, the capillary tube having an inner cross-sectional area smaller than the chamber inner cross-sectional area and having a length, the capillary tube having a proximal segment extending outwardly from the sleeve and projecting into the chamber;

wherein the inner cross-sectional area of the chamber is configured to be larger than the inner cross-sectional area of the supply tube so that the chamber volume resulting from the length of the chamber and the chamber inner cross-sectional area slows the flow rate of the fluid received from the supply tube so that contaminants will fall out of solution of the fluid and into the chamber, whereby such separated contaminants will not be conducted by the capillary tube.

9. The infusion system of claim 8 wherein the inner cross-sectional area of the capillary tube is less than the inner cross-sectional area of the chamber.

10. The infusion system of claim 8 wherein the capillary tube has a distal end that is in fluid communication with a distal segment of a second tube that conducts fluid flowing through the capillary tube to a downstream location at the flow rate controlled by the capillary tube.

11. The infusion system of claim 8 wherein the capillary tube is surrounded by a sleeve over less than the entire length of the capillary tube, wherein the sleeve mounts the capillary tube such that the proximal end of the capillary tube projects into the chamber, the sleeve having a radially-outwardly extending mounting flange;

a first housing surrounding the sleeve and interconnecting with the distal end of the fluid supply tube forming the chamber between the distal end of the fluid supply tube and the sleeve wherein all flow through the chamber must proceed through the capillary tube;

a second housing surrounding the sleeve and interconnecting with a downstream segment of a second tube into which the capillary tube feeds fluid;

the first and second housings mounted over the sleeve and abutting the mounting flange.

12. A method for restricting flow of medicament through a fluid supply tube comprising:

pumping medicament into the fluid supply tube at a first instantaneous velocity;

slowing the velocity of medicament through the fluid supply tube at a point downstream to a second instantaneous velocity that is less than the first such that contaminants in the medicament fall out of solution and are separated from the liquid of the medicament; and

conducting the liquid of the medicament from the point where the contaminants are separated from the segment preventing the contaminants from further downstream flow.