Infusion pump

• US 8,353,872 B2
• Filed: 11/09/2011
• Issued: 01/15/2013
• Est. Priority Date: 12/18/2009
• Status: Expired due to Fees

• Current Assignee: Sims Company
• Original Assignee: Sims Company
• Inventors: Kawamura, Yasuhiro
• Primary Examiner(s): Mehta, Bhisma
• Application Number:
  US13/292,710
• Publication Number:
  US 20120053560A1
• Time in Patent Office: 433 Days
• Field of Search: 604/131, 604/151, 417/413.1, 417/413.2
• US Class Current: 604/151
• CPC Class Codes: A61B 5/02152 specially adapted for venous pressure
• CPC Class Codes: A61M 2205/0244 Micromachined materials, e.g. made from silicon wafers, microelectromechanical systems [MEMS] or comprising nanotechnology
• CPC Class Codes: A61M 2205/0294 Piezoelectric materials
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3341 stabilising pressure or flow to avoid excessive variation
• CPC Class Codes: A61M 2205/3355 Controlling downstream pump pressure
• CPC Class Codes: A61M 2205/3553 remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/70 with testing or calibration facilities
• CPC Class Codes: A61M 2230/30 Blood pressure A61M2230/04 takes precedence
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14228 with linear peristaltic action, i.e. comprising at least three pressurising members or a helical member
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/16877 Adjusting flow; Devices for setting a flow rate
• CPC Class Codes: A61M 5/16886 for measuring fluid flow rate, i.e. flowmeters
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

Infusion pumps according to the present invention maximize fluid throughput while minimizing vaporization of gas by employing specific flow path architecture, flow path dimensional ranges, and voltage and frequency ranges for activation of piezoelectric bodies.

Claims

1. An infusion pump comprising:

a first fluid chamber channel;

an inlet channel and an outlet channel, each formed on opposite sidewalls of the fluid chamber, the inlet channel and the outlet channel each continuously open to fluid flow and each comprising a differently configured channel constriction;

the fluid chamber having a chamber depth that is shallowest proximate the inlet channel and deepest proximate the outlet channel; and

a piezoelectric body having a first side attached to an exterior surface of the fluid chamber and a second side attached to an electrode.

2. The infusion pump of claim 1 wherein the first chamber depth varies at an angle greater than zero degrees and less than or equal to an angle of 10 degrees relative to an exterior surface of the chamber.

3. The infusion pump of claim 1 wherein the fluid chamber further comprises a length to width ratio of 4.

4. The infusion pump of claim 1 wherein a width of the inlet channel varies along at least two different lengths of the inlet channel.

5. The infusion pump of claim 1 wherein the fluid chamber is formed at least in part of a metal.

6. The infusion pump of claim 1 further comprising a second fluid chamber in fluid communication with the inlet channel and the outlet channel.

7. The infusion pump of claim 1 wherein a ratio of the dimension of the inlet channel constriction to a dimension of the inlet channel upstream of the inlet channel constriction is 0.13 to 0.67.

8. The infusion pump of claim 1 wherein an angle formed by opposite walls of the inlet channel between the inlet channel constriction and a fluid chamber inlet is approximately 0.0005 degrees.

9. The infusion pump of claim 1 further comprising a first body containing at least the piezoelectric body and a second body containing at least a power supply circuit.

10. The infusion pump of claim 9 wherein the first body is disposable.

11. A method for providing an infusion fluid to a patient:

maintaining open to continuous fluid flow an inlet channel and an outlet channel that are in fluid communication with a fluid chamber having a depth that is shallowest proximate the inlet channel and deepest proximate the outlet channel;

applying a voltage to a piezoelectric body attached to an exterior surface of the fluid chamber;

creating a resonance in a fluid in the fluid chamber;

constricting a dimension of the inlet channel and a dimension of the outlet channel differentially;

creating a net directional flow of the fluid out the outlet channel.

12. The method of claim 11 wherein the step of applying a voltage to a piezoelectric body attached to an exterior surface of the fluid chamber having a variable depth comprises applying a voltage in the range of 20 to 100 volts.

13. The method of claim 11 wherein the step of applying a voltage to a piezoelectric body attached to an exterior surface of the fluid chamber having a variable depth comprises controlling the rate of rise of voltage, wherein the rate of rise forms an angle relative to a vertical line in the range of 3 to 45 degrees.

14. The method of claim 11 wherein the step of applying a voltage to a piezoelectric body attached to an exterior surface of the fluid chamber comprises applying a voltage at a frequency in the range of 50 to 4500 Hz.

15. The method of claim 11 wherein the step of creating a resonance in a fluid in the fluid chamber comprises controlling selectively at least two of the variable selected from the group consisting of:

(1) a ratio of the dimension of an inlet channel constriction to a dimension of an inlet channel upstream of the inlet channel constriction;

(2) a length to width ratio of the fluid chamber; and

(3) a variation in a fluid chamber depth along a length of the fluid chamber, in order maximize a fluid flow while minimizing vaporization of dissolved gas.