Volumetric pump/valve

• US 5,710,401 A
• Filed: 06/06/1995
• Issued: 01/20/1998
• Est. Priority Date: 11/23/1993
• Status: Expired due to Term

• Current Assignee: Sterling Investments LC
• Original Assignee: Sarcos Group
• Inventors: Jacobsen, Stephen C., Davis, Clark C.
• Primary Examiner(s): Gellner, Michael L.
• Assistant Examiner(s): Friedhofer, Michael A.
• Application Number:
  US08/470,999
• Time in Patent Office: 959 Days
• Field of Search: 200/81 R, 200/81.9 R, 200/82 R, 200/83 R, 200/83 A, 200/83 J, 200/83 N, 200/83 WM, 200/83 B, 200/83 P
• US Class Current: 200/83.00J
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 2201/1208 Angular position of the shaft
• CPC Class Codes: F04B 2205/05 Pressure after the pump outlet
• CPC Class Codes: F04B 49/12 by varying the length of stroke of the working members
• CPC Class Codes: F04B 53/02 Packing the free space between cylinders and pistons
• CPC Class Codes: F04B 53/164 Stoffing boxes
• CPC Class Codes: F04B 7/0015 and having a slidable movement
• CPC Class Codes: F04B 9/02 the means being mechanical
• CPC Class Codes: F04B 9/045 the means being eccentrics
• CPC Class Codes: F05C 2225/04 PTFE [PolyTetraFluorEthylene]
• CPC Class Codes: F16K 41/12 with approximately flat diaphragm
• CPC Class Codes: Y10T 137/791 Ball valves
• CPC Class Codes: Y10T 137/86228 With communicating opening in common walls of tanks or compartments
• CPC Class Codes: Y10T 137/86799 With internal flow passage
• CPC Class Codes: Y10T 137/86879 Reciprocating valve unit
• CPC Class Codes: Y10T 137/87708 With common valve operator

Abstract

A volumetric pump for administering intravenous fluids to a patient comprises a housing having an elongate cavity therein with an open and a closed end. A resilient sheet of material having a centrally-located aperture covers the open end, and a pump shaft is slidably disposed through the aperture to form a sphincter seal therebetween. An inlet conduit leading from a fluid source (an IV bag) passes through the housing into the cavity near the open end thereof, and an outlet conduit leading to a fluid sink (the patient) passes through the housing from the cavity near the closed end thereof. The shaft is driven back and forth in reciprocating motion inwardly and outwardly of the cavity to produce, respectively, a positive pressure forcing fluid out of the outlet conduit to the fluid sink, and a negative pressure forcing fluid from the fluid source through the inlet conduit.

Claims

1. A switch for detecting fluid pressure comprising:

a housing defining an interior cavity;

a nonconductive diaphragm having a mounting surface and being disposed in the cavity to divide the cavity into first and second chambers;

a fluid inlet means for carrying fluid from the outside of the housing into the first chamber;

separate flexible conductive means contiguously disposed against the mounting surface of the diaphragm and extending outwardly therefrom into the second chamber for conducting electricity, such that said mounting surface defines a nonconductive/conductive boundary residing between the nonconductive diaphragm and the conductive means; and

first and second conductivity sensors disposed in the second chamber oppositely the conductive means;

said diaphragm being sufficiently flexible to bow toward the sensors under fluid pressure in the first chamber, whereby if a certain pressure is present, the diaphragm is caused to bow until the conductive means contacts the first and second conductivity sensors.

2. A switch for detecting fluid pressure comprising:

an elongate hollow housing for carrying fluid, said housing having an opening on one side;

a diaphragm disposed in the opening for preventing passage of fluid therethrough;

a flexible conductive contact operatively connected to the diaphragm and adapted to bend as fluid pressure in the housing deforms the shape of the diaphragm;

a contacting arm disposed between the diaphragm and the flexible conductive contact, and a lever arm extending outwardly from said contacting arm and being pivotally mounted at a pivot point such that said contacting arm and said lever arm are confined to pivotal movement about said pivot point;

a conductivity sensor spaced from the conductive contact under normal fluid pressures;

said conductive contact being sufficiently flexible to bend toward the sensor and touch it in response to the diaphragm deforming under a certain fluid pressure in the housing, in that said contacting arm extends in opposing directions toward said conductive contact and said diaphragm, respectively, and has sufficient length such that deformation of the diaphragm under fluid pressure causes said diaphragm to push said contacting arm against said conductive contact and bend said conductive contact toward the sensor.

3. The switch of claim 2 further comprising means disposed in the housing for normally urging the diaphragm away from the hollow of the housing.