RU2616982C2 - Low inertia temperature transducer - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention relates to field of electrical measuring equipment, specifically to thermal converter devices, and can be used for quick changing thermal processes measurement, for example, water drops temperature. Summary: temperature transducer comprises cables with thermocouple wires, for example chromel and Copel, juncture and cables attachment device. One thermocouple cable thermocouple wire and thermocouple wire of other are arranged opposite to each other and released from cable sheath along length, sufficient for eliminating of cable heat capacity effect on temperature transducer readings, and form juncture. Fixation of cable ends facing juncture, is carried out on housing, for example, by means of foil, by contact welding. Below juncture on housing water drops drain from juncture implementation element is fixed.

EFFECT: technical effect: improving temperature transducer inertial characteristics and increasing accuracy of gas-droplet flow temperature measuring under conditions, when drops weight is comparable with juncture size.

1 cl, 2 dwg

Description

The proposed technical solution relates to the field of electrical engineering, in particular to the device of thermal converters in which a thermoelectromotive force occurs in proportion to temperature, and can be used to measure rapidly changing temperature processes, for example, the temperature of water drops in pressure vessels.

Known cable thermocouples containing thermoelectrodes with an insulated or non-insulated working junction in a sheath (see GOST 23847-79) with a cable diameter of 1.0 mm or more with a thermal inertia of ε _∞ over 0.1 s, which do not allow measuring the temperature of rapidly changing temperature processes.

Thermal converters with a thinned working section (see GOST 23847-79) with a diameter of up to 0.5 mm and an index of thermal inertia ε _{∞ of} less than 0.1 s are also known, which are mainly used to measure surface temperature, since they have a low mechanical strength.

Thermal converters are known that have an open junction cable placed in a protective structure (see, for example, the book “Temperature Measurements in Nuclear Reactors”, Moscow, Atomizdat, 1975, p. 126, Fig. 3.13). Such thermocouples have an index of thermal inertia better than those with a shell, however their load-bearing structure has significant dimensions, which introduces disturbances in the controlled volume.

Known thermal converter containing an open junction in the form of a point head and two conductors. The thermal converter is equipped with a wire element in the form of a coil of nichrome, which wraps a point head or one of two conductors for heating the junction (see, for example, Russian patent No. 2390783, class G01P 5/10, published May 27, 2010). The disadvantage of the thermal converter is the low mechanical strength of the structure.

The problem to be solved is the creation of a thermal converter design with a thermal inertia index of less than 0.1 s, which has high mechanical strength.

The technical result is the creation of a thermal converter for measuring rapidly changing temperature processes, for example the temperature of water drops

The specified technical result is achieved by the fact that in a low-inertia thermal converter containing cables with thermoelectrodes, for example chromel and copel, a junction and cable fastening means, the thermoelectrode of one thermocouple cable and the thermoelectrode of another are located opposite each other and are freed from the cable sheath for a length sufficient to exclude the influence the heat capacity of the cable to the readings of the thermal converter, and form a junction; and fastening the ends of the cables facing the junction is carried out on the housing, for example, using foil, resistance welding.

Below the junction, an element is fixed on the housing for carrying out the dripping of water drops from the junction.

In FIG. 1 shows the proposed technical solution.

In FIG. 2 shows the proposed technical solution with an element for draining drops of water from the junction of the thermal converter.

The thermoelectrode 1 (for example, chromel) of one thermocouple cable 2 and the thermoelectrode 3 (for example, kopel) of another thermocouple cable 4 are located opposite each other and junction 5 is performed at a length l from the insulation sheath 5. The length l is chosen so as to exclude the influence of the heat capacity of the cable on the readings thermal converter, for example, at least 30 cable diameters on each side of the junction. Thermoelectrodes are mounted on the housing 6, for example, by means of foil 7 by contact welding. In this design, the junction of the thermal converter is securely fixed at the measuring point and does not move under the influence of the medium flow.

If necessary, below the junction 5, an element 8 is installed for dropping drops on it from the working junction of the thermal converter by changing the surface tension of the drop. Element 8 can be made in the form of one or more needles of various shapes.

The thermal converter works as follows: the thermal converter is installed in a controlled volume, when a drop of water enters junction 5, its temperature changes, the resulting thermoelectric driving force is recorded by a secondary device. Thermal inertia of the thermal converter (indicator less than 0.1 s) allows the measurement of rapidly changing temperature processes in a controlled volume. The operation of the thermal converter is tested in bench conditions.

Claims (2)

1. A low-inertia thermal converter containing cables with thermoelectrodes, for example chromel and copel, a junction and cable fastening means, characterized in that the thermoelectrode of one thermocouple cable and the thermoelectrode of the other are located opposite each other and are freed from the cable sheath for a length sufficient to exclude the influence of the heat capacity of the cable on the readings of the thermal converter, and form a junction; and fastening the ends of the cables facing the junction is carried out on the housing, for example, using foil, resistance welding. 2. Low-inertia thermal converter according to claim 1, characterized in that below the junction, an element is fixed on the housing for draining water drops from the junction.

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