Thermopile flow sensor
First Claim
1. A flow sensor, comprising:
- exactly two electrical connections;
a tubular substrate;
a series of interconnected thermocouples electrically connected to the two electrical connections, the series of interconnected thermocouples being symmetrically distributed about the substrate such that opposite ends of the substrate are uniformly heated when an alternating current is applied between the two electrical connections, thereby minimizing the effects of cross flow currents and the generation of uneven heat which arises due to the Peltier effect; and
wherein the series of interconnected thermocouples provides a voltage between the two electrical connections representing a temperature differential proportional to flow when the alternating current is removed.
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Accused Products
Abstract
A flow sensor adapted for placement along a pacing lead or other catheter comprises a thermopile formed on the outer surface of a tubular substrate. The thermopile comprises a plurality of interconnected conductors of an alternating metal type. Junctions between conductors of the thermopile are alternately located near the longitudinal ends of the flow sensor, so that a voltage generated by the thermopile indicates the difference in temperature between the ends of the flow sensor. To measure blood flow with the flow sensor, an alternating current is induced through the thermopile to heat the flow sensor in a generally symmetrical manner. A voltage generated by the thermopile is then measured to obtain a sample of the magnitude and direction of the velocity of blood flow.
45 Citations
28 Claims
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1. A flow sensor, comprising:
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exactly two electrical connections; a tubular substrate; a series of interconnected thermocouples electrically connected to the two electrical connections, the series of interconnected thermocouples being symmetrically distributed about the substrate such that opposite ends of the substrate are uniformly heated when an alternating current is applied between the two electrical connections, thereby minimizing the effects of cross flow currents and the generation of uneven heat which arises due to the Peltier effect; and wherein the series of interconnected thermocouples provides a voltage between the two electrical connections representing a temperature differential proportional to flow when the alternating current is removed.
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2. A flow sensor, comprising:
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a tubular substrate having an outer surface; a thermopile on the outer surface of the tubular substrate; means for providing heat; and an anisotropic coating deposited on the outer surface of the tubular substrate such that heat is conducted in a radial direction better than in a longitudinal or tangential direction. - View Dependent Claims (3)
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4. A method of sensing the flow of a fluid comprising the steps of:
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providing a flow sensor comprising a thermopile on a outer surface of a tubular substrate, wherein an anisotropic coating has been deposited on the outer surface of the tubular substrate; heating the flow sensor by passing a current through the thermopile; and sensing a voltage generated by the thermopile to measure a temperature difference caused by the flow of the fluid. - View Dependent Claims (5, 6, 7)
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8. A flow sensor suitable for detecting flow in two directions and for minimizing the effects of cross flows, comprising:
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a tubular substrate; a thermopile having exactly two electrical connections, the thermopile being formed by a series of interconnected thermocouples symmetrically arranged on the substrate; power generating means for providing a current to the thermopile so that heat is uniformly generated throughout the thermopile; and wherein the thermopile generates a voltage between the two electrical connections when the current has been removed, the voltage representing a temperature differential proportional to flow in one of two directions. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification