Apparatus and method for air-in-line detection

• Main Authors: FARQUHAR ALLEN B, BUTTERFIELD ROBERT D
• Format: Patent
• Language: English
• Published: 28.11.2006
• Subjects: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROMTHE BODY; HUMAN NECESSITIES; HYGIENE; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEDICAL OR VETERINARY SCIENCE; PHYSICS; TESTING

The concentration of air in a fluid delivery line is determined by monitoring output signals corresponding to the amount of air detected in the fluid and processing those signals along with information as to the time or total volume of fluid dispensed since each signal was produced. The processor determines an air concentration value based on the received signal values, with the air concentration value determined by giving greater weight to more recent signal values. Where the air concentration value exceeds a predetermined value, an alarm signal may be activated or fluid delivery may be stopped. The processor also may determine a secondary air concentration value, which may be determined from the raw signal values instead of the weighted signal values. Where the secondary air concentration value exceeds a second predetermined threshold, an alarm signal may be activated or fluid delivery may be stopped.