Bio-medical flow sensor
First Claim
1. A flow sensing system for biomedical application in measurement of low flow rate intravenous fluids, the improvement including an intravenous fluid source, and intravenous injection unit and a delivery tubing interconnecting said fluid source and said intravenous injection unit;
- flow sensing means for sensing the rate of flow through the delivery tubing including spaced apart, thermally conductive tubing metal segments disposed in said delivery tubing;
container means for enclosing said tubing metal segments, said enclosing means having thermal sensing means for providing a thermal connection with said metal tubing segments and for sensing the temperature at each of said metal tubing segments in said delivery tubing;
said enclosing means having heating means for supplying heat at the downstream metal tubing segment;
heat control means for controlling the heating means to regulate the amount of heat to said downstream metal segment as a function of the differential temperature between said two metal tubing segments; and
further including flow control means for controlling the rate of fluid through said delivery tubing, said flow control means being located between said flow sensing means and said intravenous injection unit;
said flow control means being coupled to said heat control means and responsive to said heat control means for controlling the flow of fluid through said delivery tubing.
1 Assignment
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Accused Products
Abstract
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.
143 Citations
8 Claims
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1. A flow sensing system for biomedical application in measurement of low flow rate intravenous fluids, the improvement including an intravenous fluid source, and intravenous injection unit and a delivery tubing interconnecting said fluid source and said intravenous injection unit;
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flow sensing means for sensing the rate of flow through the delivery tubing including spaced apart, thermally conductive tubing metal segments disposed in said delivery tubing; container means for enclosing said tubing metal segments, said enclosing means having thermal sensing means for providing a thermal connection with said metal tubing segments and for sensing the temperature at each of said metal tubing segments in said delivery tubing;
said enclosing means having heating means for supplying heat at the downstream metal tubing segment;heat control means for controlling the heating means to regulate the amount of heat to said downstream metal segment as a function of the differential temperature between said two metal tubing segments; and further including flow control means for controlling the rate of fluid through said delivery tubing, said flow control means being located between said flow sensing means and said intravenous injection unit; said flow control means being coupled to said heat control means and responsive to said heat control means for controlling the flow of fluid through said delivery tubing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification