Bubble detector

• US 4,312,341 A
• Filed: 12/13/1979
• Issued: 01/26/1982
• Est. Priority Date: 12/13/1979
• Status: Expired due to Term

• Current Assignee: Baxter Travenol Laboratories Incorporated (Baxter International Inc.)
• Original Assignee: Baxter Travenol Laboratories Incorporated (Baxter International Inc.)
• Inventors: Baron, John, Zissimopoulos, Nick
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Swisher, Nancy A. B.
• Application Number:
  US06/103,040
• Time in Patent Office: 775 Days
• Field of Search: 128/DIG. 13, 128/214 E, 128/214 C, 356/440, 356/410, 356/40, 222/159, 222/450, 138/103
• US Class Current: 604/67
• CPC Class Codes: A61M 5/14232 Roller pumps
• CPC Class Codes: A61M 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: Y10S 128/13 Infusion monitoring

Abstract

In a flow metering apparatus a bubble detector for detecting bubble formation in tubing subject to deformation from internal fluid pressure includes a light source and a light detector. The light detector is positioned on the opposite side of the tubing from the light source such that the light transmitted through the tubing to the detector is dependent on the presence of fluid in the tubing and on the shape of the lumen of the tubing. A control circuit responsive to the output of the detector interrupts operation of the metering apparatus when the light transmitted through the tubing falls below a predetermined minimum level. False interruptions resulting from deformation of the tubing by pressure changes in the fluid are prevented by forming members which engage the wall of the tubing adjacent the light source and light detector.

Claims

1. In a flow metering apparatus for controlling the flow of fluid through an administration set of the type having transparent tubing subject to deformation from internal fluid pressure, a bubble detector comprising, in combination:

a light source arranged at one side of the tubing;

a light detector generally arranged at the opposite side of the tubing opposite said light source and defining a light path through the tubing, said detector generating an output signal indicative of the intensity of light from said light source transmitted through the tubing, the intensity of said transmitted light being dependent on the presence of fluid within the lumen of the tubing and on the shape of the lumen between said source and said detector;

control circuit means responsive to said output signal for interrupting operation of the flow metering apparatus upon the intensity of said transmitted light falling below a predetermined minimum level; and

platen means comprising a pair of forming members engaging said tubing from opposite sides thereof about a substantial portion of the circumference of the tubing adjacent said light path for preventing deformation of the tubing and consequent changes in the intensity of said transmitted light with fluid pressure changes in the lumen of the tubing, at least one of said forming members being mounted for movement in a direction generally perpendicular to the axis of the tubing so as to be disengageable from the tubing to facilitate insertion or removal of the tubing from said platen means.

2. A bubble detector as defined in claim 1 wherein the engaging surface of said forming member conforms generally to the non-expanded shape of said tubing.

3. A bubble detector as defined in claim 2 wherein said non-expanded shape of said tubing is cylindrical.

4. A bubble detector as defined in claim 1 wherein the tubing of the flow metering apparatus is formed of vinyl.

5. A flow system for infusing fluid from a reservoir into the human body, said system including, in combination:

a length of transparent tubing, said tubing being subject to deformation from internal fluid pressure;

metering means operatively engaging said tubing for urging fluid through said tubing at a predetermined rate;

a light source arranged at one side of said tubing downline of said metering means;

a light detector generally arranged at the opposite side of said tubing opposite said light source and defining a light path through said tubing, said detector generating an output signal in response to the intensity of light from said light source transmitted through said tubing, the intensity of said transmitted light being dependent on the presence of fluid within the lumen of said tubing and on the shape of the lumen between said source and said detector;

control circuit means responsive to said output signal for interrupting operation of said flow metering apparatus upon the intensity of said transmitted light falling below a predetermined minimum level; and

platen means comprising a pair of forming members engaging said tubing from opposite sides thereof about a substantial portion of the circumference of said tubing adjacent said light path for preventing deformation of said tubing and consequent changes in the intensity of said transmitted light with fluid pressure changes in said lumen of said tubing, at least one of said forming members being mounted for movement in a direction generally perpendicular to the axis of said tubing so as to be disengageable from said tubing to facilitate insertion or removal of said tubing from said platen means.

6. A flow system as defined in claim 5 wherein the engaging surface of said forming member conforms generally to the non-expanded shape of said tubing.

7. A flow system as defined in claim 6 wherein said non-expanded shape of said tubing is cylindrical.

8. A flow system as defined in claim 5 wherein said tubing is formed of vinyl.