AIR-IN-LINE AND PRESSURE DETECTION
First Claim
1. A method of measuring air content in a sample fluid comprising:
- determining a base volume change between zero or a negative pressure and a positive pressure in a chamber;
determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and
determining air content of the sample fluid by comparing the sample volume change and the base volume change.
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Accused Products
Abstract
Methods and apparatus for air content and pressure measurement of sample fluid, especially sample fluid in association with an infusion pump. Volume change in a chamber as the chamber transitions between negative and positive pressure relates to the air content in the chamber. In particular, in an infusion pump, the volume change of infusion fluid as it transitions between being under negative pressure and positive pressure within a cassette central chamber, e.g., pumping chamber, relates to the air content in the infusion fluid. The outlet pressure of the cassette central chamber, e.g., blood pressure, can be monitored based on the cassette central chamber pressure.
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Citations
51 Claims
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1. A method of measuring air content in a sample fluid comprising:
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determining a base volume change between zero or a negative pressure and a positive pressure in a chamber;
determining a sample volume change between zero or the negative pressure and the positive pressure in the chamber with a sample fluid; and
determining air content of the sample fluid by comparing the sample volume change and the base volume change. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19-32. -32. (canceled)
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33. An apparatus for air content measurement of a sample fluid comprising:
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a central chamber;
an assembly moving in and out of the central chamber;
a pressure source connected to the assembly, and wherein the pressure source comprises a motor which generates a negative pressure in the central chamber and pumps fluid into the central chamber via the assembly, and a spring which generates a positive pressure in the central chamber and pumps fluid out of the central chamber via the assembly;
a position sensor connected to the assembly, wherein the position sensor determines a position change of the assembly; and
a processor connected to the position sensor, wherein the processor receives the position change of the assembly, calculates a base volume change between zero or a negative pressure and a positive pressure in the central, and a sample volume change between zero or a negative pressure and the positive pressure in the central chamber with a sample fluid, wherein the air content of the sample fluid is related to the sample volume change minus the base volume change. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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51-55. -55. (canceled)
Specification