Temperature sensors for precise measurement of small temperature differences and also useful in flowmeters or inclinometers comprise four resistors connected as a bridge to give variable diagonal voltages

摘要

A temperature sensor for precise measurement of small temperature differences in stationary or moving media consists of four equal thermoresistors connected to form a bridge supplied with current to give a diagonal voltage, the whole bridge being formed of a single wire (1) or of a pcb (2) of high temperature coefficient such that opposing resistances (R1-R4) are arranged symmetrically in the medium in close thermal coupling to each other in two spaced positions. A temperature sensor for precise measurement of small temperature differences especially in temperature gradients and rapid local temperature variations in stationary or moving media consists of four equal thermoresistors connected to form a bridge supplied with direct or alternating current such that equal currents flow in the two arms and variation of the resistance results in a diagonal voltage, the whole bridge being formed of a single wire (1) or of a pcb (2) with a high temperature coefficient such that opposing resistors (R1-R4) are arranged symmetrically in the medium in close thermal coupling to each other in two spaced positions. Independent claims are also included for (A) production of the temperature sensor by forming wire (1) or pcb (2) symmetrically on carrier (3) at a tilt angle of 180[deg] and folding carrier (3) at least twice along an axis (6); (B) a flowmeter for gases or liquids comprising two of the above temperature sensors arranged with their axes of symmetry at below 90[deg] to each other, each sensor being supplied with the same current by having a uniform ring distribution of resistors and each being symmetrically axially heated under axially symmetrical edge conditions for the carrier to produce a temperature gradient giving a diagonal voltage corresponding to the size and polarity; and (C) a sensor determining a tilt angle (inclinometer) obtained by fixing along the axis of a circular channel (12) a temperature sensor having a uniform ring distribution of resistors as above and heating with an electrical current with the channel in a massive block (13) and half filling with a fluid (14) (especially a silicone oil with a low viscosity-temperature) such that the temperature sensor gives a diagonal voltage corresponding to its inclination or tilt.