Precision pumping device

• US 6,234,771 B1
• Filed: 05/28/1999
• Issued: 05/22/2001
• Est. Priority Date: 06/02/1998
• Status: Expired due to Term

• Current Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Original Assignee: Bayer Corporation (Bayer AG)
• Inventors: Lapeus, David J., Richey, Randi L., Downing, William R., Whitesel, Mary Beth, Carey, Glen A.
• Primary Examiner(s): Thorpe, Timothy S.
• Assistant Examiner(s): Solak, Timothy P
• Application Number:
  US09/322,354
• Time in Patent Office: 725 Days
• Field of Search: 417/360, 417/212, 417/415
• US Class Current: 417/415
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 2203/0213 Pulses per unit of time (pulse motor)

Abstract

A precision pumping device for aspirating and dispensing different volumes of fluid is presented. The precision pumping device comprises a housing with integral anti-rotation guides, a stepper motor which drives a fine pitch lead screw, a coupling for linking the piston to the leadscrew, an anti-backlash leadscrew follower, a split hub clamp nut, and a nut for securing the chamber to the housing. A seal is provided which seals around the piston and against the chamber, as is an o-ring that is set into a groove in the chamber and seals against a flange of the seal. The precision pumping device further includes a piston and a chamber for receiving at least a portion of the piston therein. The piston and chamber are of different sizes for aspirating and dispensing different volumes of fluid. The chamber can include a single port or multiple ports. Due to the self-aligning features and the reduced number of parts, the pump can be easily changed from aspirating and dispensing a first volume of fluid to aspirating and dispensing a second volume of fluid.

Claims

1. A precision pumping device comprising:

a housing including an integral anti-rotation guide;

a first chamber removably coupled to said housing;

a first piston displaceable within a portion of said chamber, said first piston and said first chamber adapted to aspirate or dispense a first volume of fluid;

a port disposed within said chamber, said port providing fluid communication from within said chamber to outside of said chamber;

a fine pitch lead screw;

a coupling fixedly linking said piston to said leadscrew;

an anti-rotation member projecting from said coupling and into said anti-rotation guide;

a split hub clamp nut coupled to said leadscrew; and

a stepper motor attached to said housing, said stepper motor coupled to said leadscrew and operative to move said leadscrew in a first direction for moving said piston within said chamber to dispense a first volume of fluid within said chamber out of said port, said stepper motor operative to move said leadscrew in a second direction for moving said piston within said chamber to aspirate a first volume of fluid into said chamber through said port.

2. The precision pumping device of claim 1 further comprising an anti-backlash leadscrew follower coupled to said leadscrew.

3. The precision pumping device of claim 2 wherein said anti-backlash leadscrew follower is self-aligning.

4. The precision pumping device of claim 2 wherein said anti-backlash leadscrew further comprises a spring providing a biasing force between said leadscrew and said coupling.

5. The precision pumping device of claim 1 further comprising a seal disposed around said piston and against a surface of said chamber.

6. The precision pumping device of claim 5 further comprising an o-ring disposed within said chamber and against a flange of said seal.

7. The precision pumping device of claim 1 further comprising an end play lock nut disposed on an end of said stepper motor.

8. The precision pumping device of claim 1 further comprising a nut removably coupling said chamber to said housing.

9. The precision pumping device of claim 1 further comprising at least one additional port disposed in said chamber.

10. The precision pumping device of claim 1 wherein said housing comprises LEXAN having TEFLON filler.

11. The precision pumping device of claim 1 further comprising:

a second piston having a different size than the first piston, said second piston substitutable for said first piston; and

a second chamber having a different size than said first chamber, said second chamber substitutable for said first chamber, said second piston and said second chamber adapted to dispense or aspirate a second volume of liquid.