SU911280A1 - Device for measuring thermal emf - Google Patents

Description

The invention relates to thermoelectric measurements and is intended to determine the thermo-emf of minerals in ore specimens, grains or directly in rock outcrops, excavations, etc.

A device for measuring thermo-emf of alloys, containing temperature electrodes, a measuring device and a clamping device 1, is known.

The disadvantages of this device are the complexity of the design of the electrode blocks, the long time to establish the operating mode, the considerable errors resulting from the fact that in the conditions of the steady state the slightest contact with the heated electrode causes a change in its contact temperature which is practically impossible to control ..

The closest technical solution to the present invention is a device for measuring a thermo-emf containing two electrodes, a thermopile located between them, a thermopile supply source and a measuring circuit 2J.

The drawbacks of the device are a long time of setting the operating mode, a significant metrological error in measurement, the need for a complex measuring device that provides a wide range of measurements at a high-impedance input of the amplifier.

The aim of the invention is to improve the metrological characteristics and reduce the time set by the 1st operating mode in the study of minerals.

The goal is achieved

15 in that a device for measuring thermo-EMF; containing two electrodes, a thermopile located between them, a thermopile power source and a measuring circuit, is equipped with a thermopower polarity switch, consisting of two keys, a trigger and a sensor of stable time intervals, connected to the trigger input via a 25: range switch.

The drawing shows a diagram of the device.

The device contains electrodes

Claims (2)

30 1 and 2, thermopile 3, dielectric body 4, through which electrodes connected to the amplifier of measuring circuit 5 pass. Electrodes are spring-loaded by spring b and are permanently closed on plate 7. Opening of electrodes occurs when pressing a sample or sample 8. At the output of an amplifier set the dial gauge 9 with zero reference in the middle of the scale. A thermobara by means of key elements 10 and 11 can be connected either to a positive one, for example 12, then to a negative power source 13. The inputs of the keys connected to the trigger 14, the input of which through the switch 15 is connected to the sensor 16 stable time intervals. Thermal battery connection alarm. to any one of the power sources is carried out by the LED 17, the device operates in the following way. When the power is turned on, one of the outputs of the trigger 14 is set to H, on the other - O. These signals will remove the opening of one of the calls by locking the other. The current through the thermopile is 1E1THEINs in that other direction depending on the polarity of the applied voltage. The duration of this current flow is set by fiaf tHKOM 16 and by switch 15, which actually performs the function of a switch in the zone, affecting the magnitude of the temperature difference across the electrodes and thereby the magnitude of the measured signal. When you press the Sample Electrodes, the electrodes automatically go to the measuring circuit and a smoothly varying thermo-emf signal is applied. When switching the supply polarity to the thermopile due to the inertia of the thermal processes, the switch instrument will record the Maximum deviation value by a time sufficient for perception and memorization. For the change in polarity of the supply and the battery, two signal values are fixed on both sides of the zero reference. The LED on indicator 17 is used to assign the sign of the thermo-EMF. If the signal size is large, the time interval for creating the temperature difference between the electrodes and the seed decreases. the signal size itself, and so on. Thus, stable time intervals are used as a reference value, the creation of which at present is quite secure and achievable in simple ways (in the required limits of accuracy). The instrument is calibrated using reference remote thermocouples. The use of varying time intervals for switching on the thermoelement makes it possible to dispense with complications in the input circuits of the amplifier with the provision of a high-resistance input with ease of connection. The use of the unsteady temperature mode of the electrodes makes it possible to more clearly fix the contact temperature difference, which improves the metrological characteristics of the instrument. The application of the proposed device enables one to repeat the measurement results of measurements of the same minerals with an error not exceeding 3–4% in the open air, experiments under the same conditions using low-power heat sources (as for a field device) for conditions steady-state regimes give a variation of 20–25%, which greatly exceeds the requirements. nor to measurement accuracy (5–10%) for a field device of a similar purpose. Using a variable thermoelement operation mode ensures that the device is ready for operation immediately after power is turned on, while in known devices it takes 20 - 30 minutes to prepare the installation for operation. The latter circumstance is particularly significant for field conditions, where measurements can be single and acute. is a matter of saving power. The invention The device for measuring thermoEMF containing two electrodes, a thermopile located between them, a thermopile power source and a measuring circuit that differs from that, in order to improve metrological characteristics and shorten the operating mode during the study of minershov, it is equipped with a polarity switch power thermopile, consisting of two keys, a trigger and a sensor of stable time intervals, connected to the trigger input via a range switch. Sources of information taken into account in the examination 1. USSR author's certificate 442401, cl. G 01 N 25/30, 1970. 2. USSR author's certificate 553479, cl. G 01 K 7/02, 1975 (prototype). X