Peristaltic infusion pump and method

• US 4,256,437 A
• Filed: 02/01/1978
• Issued: 03/17/1981
• Est. Priority Date: 02/01/1978
• Status: Expired due to Term

• Current Assignee: Sterling Medical Devices Incorporated 1616 West SHAW AVE Fresno California
• Original Assignee: Stewart-Naumann Laboratories Incorporated
• Inventors: Brown, Fon R.
• Primary Examiner(s): Freeh, William L.
• Application Number:
  US05/874,212
• Time in Patent Office: 1,140 Days
• Field of Search: 417/45.63, 128/214 E, 128/214 F, 318/685, 318/696
• US Class Current: 417/45
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14232 Roller pumps
• CPC Class Codes: F04B 2205/50 Presence of foreign matter in the fluid
• CPC Class Codes: F04B 43/1253 by using two or more rollers as squeezing elements, the rollers moving on an arc of a circle during squeezing

Abstract

A peristaltic infusion pump is disclosed herein and includes a continuous tubular arrangement adapted to pass intravenous fluids therethrough and a peristaltic pump head mounted for rotation about a fixed axis. This pump head includes a plurality of innerconnected, circumferentially spaced tube engaging members adapted to successively engage the tubular arrangement during rotation for peristaltically pumping fluid therethrough. In a preferred embodiment, the pump includes a stepping motor which is energized in a particular way for rotating the pump head and which is also used to sense occlusion in the tubular arrangement. This preferred pump also includes a particular arrangement for detecting the index of refraction of the intravenous fluid for detecting the presence of air bubbles or the like.

Claims

1. A peristaltic infusion pump comprising:

(a) a continuous tubular arrangement adapted to pass intravenous fluids therethrough;

(b) means for supporting a predetermined tubular section of said arrangement in an exposed and readily accessible position;

(c) a peristaltic pump head mounted for rotation about a fixed axis, said pump head including a plurality of interconnected, circumferentially spaced tube engaging members adapted to successively engage said predetermined tubular section during rotation of said pump head for peristaltically pumping fluid through said tubular arrangement; and

(d) means for rotating said pump head in incremental steps about said axis, said rotating means including electromagnetic stepping motor means; and

(e) means sensing the load of said motor means during operation of said pump for sensing occlusion in said tubular arrangement.

2. A pump according to claim 1 wherein said stepping motor means includes a fixed stator, a cooperating rotor, an output shaft connecting said rotor with said pump head and electromagnetic coil means which, when subjected to successive predetermined current signals, drives said rotor through successive circumferentially spaced magnetic detents corresponding to said signals and wherein said occlusion sensing means includes means for sensing the energy level across said coil means and means for comparing said level to a reference level.

3. A pump according to claim 2 wherein said coil means includes a plurality of electromagnetic coils and wherein said energy sensing means includes a capacitor connected across each of said coils, means for charging each of said capacitors during the intervals between said signals, each of said capacitors discharging through its connected coil during said signals and means for sensing the energy across each of said coils during said discharge.

4. A pump according to claim 3 wherein said energy sensing means includes means for adding and integrating said energy across each of said coils and producing a signal indicative thereof.

5. A peristaltic infusion pump, comprising:

(a) a continuous tubular arrangement adapted to pass intravenous fluid therethrough;

(b) means for supporting first and second predetermined tubular sections of said arrangement in exposed and readily accessible positions,

(c) a peristaltic pump head mounted for rotation about a fixed axis, said pump head including a plurality of interconnected, circumferentially spaced tube engaging members adapted to successively engage said first predetermined tubular section during rotation of said pump head for peristaltically pumping fluid through said tubular arrangement;

(d) means for rotating said pump head about said axis; and

(e) means for detecting the index of refraction of said fluid as said fluid passes through said second tubular section, said detecting means including

(i) electrical light source means positioned on one side of said tubular section for passing light therethrough, the amount of light passing through said second section at any given time during operation of said pump depending upon the index of refraction of fluid passing through said second section,

(ii) electrical light sensor means positioned on the other side of said second tubular section for sensing said passed light and producing an output signal corresponding to the amount of said passed light,

(iii) feedback means responsive to said output signal and connected with said light source means for maintaining the magnitude of said light source means at a level corresponding to the index of refraction of said fluid, said feedback means including low pass filter means for preventing passage of any abrupt momentary changes in said output signal from effecting the intensity of said light source means, whereby the magnitude of said light source means is maintained at a steady state level corresponding to the normal index of refraction of said fluid, and

(iv) means responsive to said abrupt and momentary changes in said output signal for producing a warning signal at a predetermined terminal point in response thereto, said last-mentioned means including high pass filter means for preventing said output signal from causing the production of said warning signal at said terminal point when said output signal corresponds to a steady state index of refraction of said fluid.

6. A pump according to claim 5 wherein said feedback means includes low pass filter means blocking the passage of any abrupt momentary changes in said output signal, whereby the magnitude of said light source is maintained at a steady state level corresponding to the normal index of refraction of said fluid.

7. A pump according to claim 6 wherein said detecting means includes means responsive to said abrupt and momentary changes in said output signal for producing a warning signal in response thereto, said last-mentioned means including high pass filter means blocking the passage of said output signal when the latter corresponds to a steady state index of refraction of said fluid.