| 摘要 |
A bio-medical flow sensor (FIG. 1) including a packageable unit of a bottle (10), tubing (11) and hypodermic needle (12) which can be pre-sterilized and is disposable. The tubing (11) has spaced apart tubular metal segments (18,19). The temperature of the metal segments and fluid flow therein is sensed by thermistors (23,24) and at a downstream location heat is input by a resistor 25 (FIG. 2) to the metal segment (19) by a control electronics (16, FIG. 2). The fluid flow and the electrical power required of the resistor (25) to maintain a constant temperature differential between the tubular metal segments (18,19) is a measurable function of fluid flow through the tubing (11). The differential temperature measurement is made in a control electronics 16 (FIG. 2) and also can be used to control a flow control valve or pump (17) on the tubing (11) to maintain a constant flow in the tubing (11) and to shut off the tubing when air is present in the tubing.
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