Flow metering apparatus for a fluid infusion system

• US 4,217,993 A
• Filed: 12/02/1977
• Issued: 08/19/1980
• Est. Priority Date: 12/02/1977
• Status: Expired due to Term

• Current Assignee: Baxter Travenol Laboratories Incorporated
• Original Assignee: Baxter Travenol Laboratories Incorporated
• Inventors: Jess, Thurman S., Shim, Norm
• Primary Examiner(s): Rolla, Joseph J.
• Application Number:
  US05/856,863
• Time in Patent Office: 991 Days
• Field of Search: 222/14-22, 222/63, 222/71, 128/214 E, 128/214 F, 128/DIG. 12, 128/DIG. 13
• US Class Current: 222/14
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: G05D 7/0676 by action on flow sources G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10S 128/13 Infusion monitoring

Abstract

A system for infusing fluids into the human body includes a peristaltic-type metering apparatus which controls the flow of fluid through a disposable administration set. The metering apparatus includes a control system which allows the volume and rate of flow of the fluid to be infused to be accurately preset by the operator. The control system provides an alarm function in the event of malfunction of the pump or occlusion of the tubing of the administration set, and a minimum pumping rate for maintaining fluid flow through the system after the desired volume of fluid has been infused. Novel power supply circuitry within the control system renders the system immune to power line transients, and a novel bubble detector circuit provides for more reliable detection of air bubbles in the tubing. A mechanical linkage between the pressure plate and downline flow restriction plunger of the metering apparatus provides for convenient loading of the administration set and for automatic closure of the plunger prior to use.

Claims

1. Metering apparatus for controlling the flow of fluid through a fluid infusion set, comprising:

a housing;

a rotor mounted on said housing for rotation about a fixed axis, said rotor including a plurality of pressure rollers disposed about the circumference thereof;

means including a pressure plate for positioning a tubing segment of the administration set in compressive engagement with at least a portion of said rollers whereby fluid is pumped through said tubing segment with rotation of said rotor;

means including a stepper motor for driving said rotor;

first motor control means for generating stepping pulses at a first predetermined rate for controlling the rotation of said stepper motor to obtain a desired flow rate through said tubing segment;

second motor control means for generating stepping pulses at a second predetermined rate for maintaining a desired minimum flow rate through said tubing segment;

volume totalizer means including a register responsive to said stepping pulses for interrupting application of stepping pulses from said first motor control means and initiating application of stepping pulses from said second motor control means to said stepper motor upon passage of a desired volume of fluid through said tubing segment; and

inhibiting means responsive to the flow rate established by said first motor control means for inhibiting operation of said second motor control means when said predetermined rate is less than a predetermined maximum rate.

2. Metering apparatus as defined in claim 1 wherein said predetermined maximum rate corresponds to said second predetermined rate.

3. Metering apparatus as defined in claim 1 including a source of clock pulses, and wherein said first and second motor control means include respective first and second registers responsive to said clock pulses for producing said stepping pulses upon occurrence of respective predetermined numbers of said clock pulses, the predetermined number of pulses required by said first register is variable to establish a desired infusion rate, and wherein said inhibiting means is responsive to the requirement of said first register.

4. Metering apparatus as defined in claim 3 wherein said requirement of said first register is dependent on the counting state of a third register, and said inhibiting means is responsive to the counting state of said third register.

5. Metering apparatus for controlling the flow of fluid through a fluid infusion set, comprising:

flow control means operatively associated with a tubing segment of the infusion set and responsive to applied control pulses for producing an incremental flow of predetermined volume through the infusion set upon occurrence of each control pulse;

first rate control means for generating control pulses at a first predetermined rate for controlling the operation of said flow control means to obtain a desired flow rate through said tubing segment;

second rate control means for generating control pulses at a second predetermined rate for controlling the operation of said flow control means to maintain a desired minimum flow rate through said tubing segment;

volume totalizer means including a register responsive to said control pulses for interrupting application of control pulses from said first rate control means and initiating application of control pulses from said second rate control means to said flow control means upon passage of a desired volume of fluid through said tubing segment; and

inhibiting means responsive to the flow rate established by said first rate control means for inhibiting operation of said second rate control means when said predetermined rate is less than a predetermined maximum rate.

6. Metering apparatus as defined in claim 5 wherein said predetermined maximum rate corresponds to said second predetermined rate.

7. Metering apparatus as defined in claim 5 including a source of clock pulses, and wherein said first and second rate control means include respective first and second registers responsive to said clock pulses for producing said control pulses upon occurrence of respective predetermined numbers of said clock pulses, the predetermined number of pulses required by said first register is variable to establish a desired infusion rate, and wherein said inhibiting means is responsive to the requirement of said first register.

8. Metering apparatus as defined in claim 7 wherein said requirement of said first register is dependent on the counting state of a third register, and said inhibiting means is responsive to the counting state of said third register.

9. Metering apparatus operable in an environment subject to liquid spillage for controlling the flow of fluid through a fluid infusion set, comprising:

a housing substantially sealed against entry of said spilled liquid;

flow control means mounted on said housing operatively associated with a tubing segment of the infusion set and responsive to applied control pulses for producing an incremental flow of predetermined volume through the infusion set upon occurence of each control pulse;

rate control means for generating control pulses for application to said flow control means, each of said control pulses providing a flow of predetermined incremental volume through said tubing segment;

a bi-directional register;

means for interrupting the operation of said flow control means upon said register reaching a predetermined reference counting state;

volume preset means comprising a source of repetitive pulses, and user-actuable momentary action switch means for applying said pulses to said register, for causing said bi-directional register to count up to establish an initial counting state in said register prior to initial actuation of said flow control means; and

means for applying said control pulses to said bi-directional register to cause said register to count down in response to said control pulses whereby said register reaches said reference counting state upon a desired volume of fluid being infused through the infusion set.

10. Fluid metering apparatus as defined in claim 9 wherein said reference counting state comprises a zero counting state, and wherein display means responsive to the counting state of said bi-directional counter are provided for indicating the volume of fluid remaining to be infused by the apparatus.

11. Fluid metering apparatus as defined in claim 9 wherein said user-actuable switch means comprise an inwardly-deformable section of said housing, said switch being mounted within said housing in operative engagement with said housing whereby said switch is actuated with user-initiated deformation of said housing section.