Load cell pressure sensor for pump cassette

• US 5,319,979 A
• Filed: 12/15/1992
• Issued: 06/14/1994
• Est. Priority Date: 12/15/1992
• Status: Expired due to Term

• Current Assignee: Hospira Incorporated (Pfizer Inc.)
• Original Assignee: Abbott Laboratories
• Inventors: Abrahamson, Kent D.
• Primary Examiner(s): Chilcot, Jr., Richard E.
• Assistant Examiner(s): FELBER, JOSEPH LEON
• Application Number:
  US07/991,024
• Time in Patent Office: 546 Days
• Field of Search: 128/DIG. 12, 128/DIG. 13, 128/DIG. 3, 128/748, 128/675, 422/100, 422/112, 73/723, 73/745, 73/DIG. 4
• US Class Current: 73/745
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: G01L 9/006 of metallic strain gauges fixed to an element other than the pressure transmitting diaphragm

Abstract

The present invention relates to a compression load cell used to monitor pressure in a diapragm cassette pumping system. A plunger is axially slidable in a linear bearing and has a first end in contact with the cassette and the second end in contact with the load cell. The force signals have a direct relationship with the pressure in the cassette.

Claims

1. A pressure detection mechanism for use with a processor controlled pumping apparatus having a removable pumping cassette, the detection mechanism comprising:

a mechanism housing mounted in the pumping apparatus;

means for sensing force mounted in the housing;

a plunger axially slidable in the housing having a first and second end, the first plunger end adapted for perpendicular abutting contact with the pumping cassette, the second plunger end adapted for abutting contact with the force sensing means;

bearing means mounted in the housing for providing axial sliding for the plunger to axially contact the sensing means;

biasing means mounted on the housing for biasing the sensing means axially into contact with the housing; and

means for transmitting force signals from the sensing means to the processor of the pumping apparatus.

2. The pressure sensor of claim 1 wherein the sensing means is a compression load cell.

3. The pressure sensor of claim 2 wherein the bearing means is a linear bearing.

4. The pressure sensor of claim 3 wherein the biasing means is a helical spring.