Pressure-responsive flow regulator and drug delivery devices employing the same

• US 6,254,576 B1
• Filed: 11/18/1999
• Issued: 07/03/2001
• Est. Priority Date: 11/18/1999
• Status: Expired due to Fees

• Current Assignee: Medrip Limited
• Original Assignee: Medrip Limited
• Inventors: Shekalim, Avraham
• Primary Examiner(s): Seidel, Richard K.
• Assistant Examiner(s): Maynard, Jennifer
• Application Number:
  US09/443,112
• Time in Patent Office: 593 Days
• Field of Search: 604/68-71, 604/151, 604/152, 604/140, 604/141, 604/143, 604/246, 604/247, 604/249, 604/248, 604/118, 604/251, 137/501, 137/504, 422/103
• US Class Current: 604/246
• CPC Class Codes: A61M 5/16881 Regulating valves on-off valves, e.g. clamps A61M39/28
• CPC Class Codes: G05D 7/0113 the sensing element acting as a valve
• CPC Class Codes: Y10T 137/7788 Pressures across fixed choke

Abstract

A fluid flow regulator of a type having a variable outlet defined by a spacing between an outlet aperture and a flexible diaphragm, and in which the position of the flexible diaphragm varies as a function of a pressure differential between a sensing chamber on a first side of the diaphragm and an outlet chamber on a second side of the diaphragm. The regulator includes an adjustable flow impedance configuration in the flow path from the sensing chamber to the outlet chamber has a two elements providing opposing cylindrical surfaces in sliding contact. One of the cylindrical surfaces has a groove configured to define a flow-attenuating passageway having a net flow vector substantially parallel to the axis of the cylindrical surfaces. Axial relative movement between the elements causes a variation in an extent of overlap between the cylindrical surfaces, thereby varying an operative length of the flow-attenuating passageway.

Claims

1. A fluid flow regulator comprising a variable outlet defined by a spacing between an outlet aperture and a flexible diaphragm, and in which the position of the flexible diaphragm varies as a function of a pressure differential between a sensing chamber on a first side of the diaphragm and an outlet chamber on a second side of the diaphragm, an adjustable flow impedance configuration being disposed in a flow path passing from a first point in substantially direct fluid communication with said sensing chamber to said outlet chamber, the ajustable flow impedance configuration including:

(a) a first element providing a first substantially cylindrical outer surface, said first cylindrical surface defining a central axis; and

(b) a second element providing a second substantially cylindrical inner surface deployed coaxially, and in sliding contact, with said first surface,

wherein at lease one of said first and second cylindrical surfaces features at least one groove configured to define a flow-attenuating passageway between said first and second cylindrical surfaces, said flow-attenuating passageway having a net flow vector substantially parallel to said axis,

said first and second elements being configured such that axial movement of said first element relative to said second element causes a variation in an extent of overlap between said first and second cylindrical surfaces, thereby varying an operative length of said flow-attenuating passageway.

2. The adjustable flow impedance configuration of claim 1, wherein said at least one groove is a helical groove.

3. The adjustable flow impedance configuration of claim 1, wherein said first element features a first threaded adjustment portion and said second element features a complementary threaded adjustment portion deployed in engagement with said first threaded adjustment potion such that rotation of said first element relative to said element about said axis generates movement of said first element relative to said second element along said axis.

4. The adjustable flow impedance configuration of claim 3, wherein said operative length of said flow-attenuating passageway varies in a substantially continuous manner with rotation of said first element relative to said second element about said axis over a range of a plurality of revolutions of said relative rotation.

5. The adjustable flow impedance configuration of claim 1, wherein said at least one groove has at least a first portion configured to produce a flow-attenuating passageway having a first cross-sectional area and a second portion configured to produce a flow-attenuating passageway having a second cross-sectional area greater than said first cross-sectional area.

6. A constant flow fluid delivery device comprising:

(a) at least one body component defining a cavity;

(b) a flexible diaphragm deployed within said cavity so as to divide said cavity into a storage chamber and an outlet-side chamber;

(c) at least one flow-path-defining component associated with said body so as to define a flow path from a first point in substantially direct fluid communication with said storage chamber passing via a fluid flow restriction to said outlet-side chamber, said fluid flow restriction being formed as a flow-attenuating passageway lying substantially on a virtual cylinder;

(d) an outlet from said outlet-side chamber, said outlet being configured such that flexing of said diaphragm in a given direction in response to increased pressure in said storage chamber restricts flow through said outlet; and

(e) a pressure applicator deployed within said storage chamber so as to apply above-atmospheric pressure to a fluid within said storage chamber,

wherein at least part of said storage chamber lies concentrically within the virtual cylinder of said flow-attenuating passageway.

7. The fluid delivery device of claim 6, wherein said at least one flow-path-defining component is configured such that a flow impedance of said fluid flow restriction is adjustable by axial movement of said at least one flow-path-defining component relative to said body component.

8. The fluid delivery device of claim 6, wherein said pressure applicator includes a spring-loaded piston.

9. The fluid delivery device of claim 8, wherein said spring-loaded piston is configured to be manually retractable to facilitate filling of said storage chamber.

10. The fluid delivery device of claim 6, wherein said pressure applicator includes an inflatable balloon.