Split piston metering pump

• US 10,004,845 B2
• Filed: 04/18/2014
• Issued: 06/26/2018
• Est. Priority Date: 04/18/2014
• Status: Active Grant

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Focht, Kenneth, Gordon, Joseph, Perry, Matthew J., Fisk, Justin
• Primary Examiner(s): Sirmons, Kevin C
• Assistant Examiner(s): LEGETTE, TIFFANY
• Application Number:
  US14/256,365
• Publication Number:
  US 20150297825A1
• Time in Patent Office: 1,530 Days
• Field of Search: 604151, 604155
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/1422 with double acting or multiple pistons

Abstract

A micropump according to the invention uses axially oriented pistons to define a pump volume. Translating the pistons axially with respect to each other within a pump housing draws a metered amount of fluid into the pump volume from a reservoir port for delivery to a cannula port when the space is collapsed. Radially situated seals on the pistons cooperate with the axial movement to close off and open the cannula port and the reservoir port respectively at different positions of the piston stroke.

Claims

1. A micropump for delivery of medication by infusion, comprising:

a reservoir;

a cannula;

a motor;

a gear;

a drive rack;

a tubular pump housing having a first aperture in fluid communication with the reservoir and a second aperture in fluid communication with the cannula;

a drive piston and a floating piston axially oriented within the pump housing;

the drive piston and the floating piston being positioned to close the first and second aperture at first and second axial positions, respectively, of the drive piston and floating piston within the pump housing;

wherein

the motor is engaged to the gear and the gear is engaged to the drive rack to translate the drive piston axially with respect to the floating piston, wherein translating the drive piston with respect to the floating piston defines a pump volume space within the pump housing; and

wherein the floating piston is driven by the drive piston;

further comprising;

a pair of radially positioned O-ring seals on the floating piston frictionally engaged with an interior surface of the pump housing preventing movement of the floating piston due to positive and negative pressure within the pump volume space;

wherein the drive piston is coupled to the floating piston, and the drive rack is axially oriented with respect to the pump housing and coupled to the drive piston to translate the drive piston in the pump housing; and

further comprising;

a first hook on the floating piston;

a second hook on one end of the drive piston coupled to the first hook on the floating piston;

a third hook on a second end of the drive piston axially opposite said first end of the drive piston; and

a fourth hook on the drive rack coupled to the third hook on the drive piston;

a gap between the first hook and the second hook permitting defined axial movement of the floating piston with respect to the drive piston; and

a gap between the third hook and the fourth hook permitting defined axial movement of the drive rack with respect to the drive piston.

2. A micropump for delivery of medication by infusion, comprising:

a reservoir;

a cannula;

a motor;

a gear;

a tubular pump housing having a first aperture in fluid communication with the reservoir and a second aperture in fluid communication with the cannula;

a drive rack operatively connected to the gear;

a drive piston in the pump housing;

a floating piston axially aligned with the drive piston and coupled to the drive piston;

at least one radial seal on the floating piston in frictional engagement with an interior surface of the pump housing, and at least one radial seal on the drive piston in frictional engagement with an interior surface of the pump housing;

wherein

the motor is engaged to the gear, the gear is engaged to the drive rack and the drive rack is engaged to the drive piston to translate the drive piston and the floating piston axially within the pump housing;

wherein

translating the drive piston with respect to the floating piston defines a pump volume space within the pump housing; and

wherein

the floating piston closes the first aperture and the drive piston closes the second aperture at different axial positions of the drive piston and floating piston within the pump housing; and

wherein the drive piston drives the floating piston axially;

further comprising

a first hook on the floating piston;

a second hook on one end of the drive piston coupled to the first hook on the floating piston;

a third hook on a second end of the drive piston axially opposite said first end of the drive piston; and

a fourth hook on the drive rack coupled to the third hook on the drive piston;

a gap between the first hook and the second hook permitting defined axial movement of the floating piston with respect to the drive piston; and

a gap between the third hook and the fourth hook permitting defined axial movement of the drive rack with respect to the drive piston.