Method and apparatus for metered infusion of fluids

A flow system for infusing a fluid from a supply reservoir into the human body, comprising, in combination:

• a length of flexible-walled tubing extending from the supply reservoir to the body, said tubing exhibiting incomplete restoration upon repeated compressive cycling thereof;
• means including a rotor having along its circumference a plurality of pressure members, at all times at least one of said pressure members being in compressive engagement with the sidewall of said tubing and completely occluding the lumen thereof;
• means including a pressure plate for bringing said tubing into compressive engagement with said one of said pressure members;
• means for rotatably driving said rotor whereby the lumen of said tubing is repetitively and progressively compressed and restored along said segment to urge fluid through said tubing;
• and
• flow restriction means for continuously at least partially restricting the lumen of said tubing downline of said tubing segment to increase the pressure of the fluid within said segment downline of said point of engagement of said pressure member to assist in reformation of said tubing for improved metering accuracy.

Metering apparatus for infusing a fluid from a supply reservoir to the human body through a length of flexible-walled tubing of the type exhibiting incomplete restoration upon repeated compressive cycling thereof, comprising, in combination:

• means continuously including at least one pressure means compressively engaged to the sidewall of the tubing for completely occluding the lumen thereof;
• means for advancing the point of engagement of said pressure means along a segment of the tubing, the lumen of the tubing being repetitively and progressively compressed and restored along said segment to urge fluid through the tubing;
• and
• flow restriction means for continuously at least partially restricting the lumen of the tubing downline of said tubing segment to increase the pressure of the fluid within said segment downline of said point of engagement to assist in reformation of the tubing for improved metering accuracy.

Metering apparatus for infusing a fluid from a supply reservoir to the human body through a length of flexible-walled fubing of the type exhibiting incomplete restoration upon repeated compressive cycling thereof;

• comprising;
• means including a rotor having along its circumference a plurality of pressure members, at all times at least one of said pressure members being in compresive engagement with the sidewall of the tubing and completely occluding the lumen thereof;
• means including a pressure plate for bringing the tubing into compressive engagement with said one of said pressure members along a segment of said tubing;
• means for rotatably driving said rotor whereby the lumen of the tubing is repetitively and progressively compressed and restored along said segment to urge fluid through the tubing;
• and
• flow control means for continuously at least partially restricting the lumen of the tubing downline of said tubing segment to increase the pressure of the fluid within said segment to increase the pressure of the fluid within said segment downline of point of engagement of said pressure member to assist in reformation of the tubing for improved metering accuracy.

Metering apparatus for infusing a fluid from a supply reservoir to the human body through a length of flexible-walled tubing of the type exhibiting incomplete restoration upon repeated compressive cycling thereof, comprising, in combination:

• means including a rotor having in equi-spaced relationship along its circumference a plurality of pressure members, at all times at least one of said pressure members being in compressive engagement with the sidewall of said tubing and completely occluding the lumen thereof;
• means including a pressure plate for bringing said tubing into compressive engagement with said one of said pressure members only over a segment of said tubing substantially corresponding to the spacing of said pressure memebers on the curcumference of said rotor;
• means for rotatably driving said rotor whereby the lumen of said tubing is repetitively and progressively compressed and restored along said segment to urge fluid through said tubing;
• detector means downline of said tubing segment and upline of said flow restriction means for detecting the presence of undissolved gas in the lumen of said tubing;
• and
• flow restriction means comprising a movable plunger spring-biased against the wall of said tubing, and having a wedge-shaped working surface of relatively small area bearing against said tubing generally perpendicular to the direction of flow therein, and a control surface of relatively larger area extending substantially parallel to the direction of flow therein and upline from said working surface for responding to pressure changes in said tubing, for continuously at least partially restricting the lumen of said tubing downline of said tubing segment to increase the pressure of the fluid within said segment downline of said point of engagement of said pressure member to assist in reformation of said tubing for improved metering accuracy.

The method of infusing a fluid from a supply reservoir into the human body, comprising the steps of:

• establishing a flow path between the supply reservoir and the human body through a length of flexible-walled tubing of the type exhibiting incomplete restoration upon repeated compressive cycling thereof;
• continuously compressing the sidewall of said tubing so as to completely occlude said tubing;
• repetitively advancing the point of compression of said tubing along a segment thereof whereby the lumen of said tubing is repetitively and progressively compressed and restored along said segment to urge fluid through said tubing;
• and
• at least partially restricting the lumen of said tubing downline of said tubing segment to increase the pressure of the fluid within said segment downline of said point of compression to assist in reformation of said tubing segment improved metering accuracy.