Infrared reflective air-in-line sensor system

A cassette comprising:

• a rigid frame;
• a tube;
• and
• at least one adapter comprising first and second cylindrical portions defining a fluid flow channel, the first cylindrical portion comprising two adjacent wedge-shaped protrusions, each wedge-shaped protrusion having at least a portion that is infrared transmittive and each protrusion defining an outer surface and an inner surface, the fluid flow channel extends through both of the first and second cylindrical portions, and a portion of the interior surface is infrared transmissive.

A sensor system comprising:

• a pumping device comprising at least one infrared reflective sensor having an infrared light emitter and an infrared detector;
• and
• a cassette removably attached to the pumping device, the cassette comprising a tube and at least one adapter comprising first and second cylindrical portions defining a fluid flow channel, the first hollow cylindrical portion comprising first and second adjacent wedge-shaped protrusions, each wedge-shaped protrusion having at least a portion that is infrared transmittive and each protrusion defining an outer surface and an inner surface, the fluid flow channel extends through both of the first and second cylindrical portions, and a portion of the interior surface is infrared transmissive,
• wherein the infrared reflective sensor is positioned so that an infrared light can be transmitted through the outer surface of a first wedge-shaped protrusion and at least a portion of the infrared light reflected off an inner surface of the first cylindrical portion can be detected by the infrared detector.