A thermocouple welding circuit and thermocouple welding device for testing laboratory

Abstract

The invention discloses a welding circuit for detecting a thermocouple for a lab and a thermocouple welding device. The welding circuit comprises a control chip, a welding current control circuit module, a capacity discharge circuit module, a man-machine interaction module and a storage module. The thermocouple welding device is formed based on the welding circuit. The control chip outputs PWM signals with different duty ratios to adjust the magnitude of welding currents, the welding currents are adjustable and controllable in the welding process, and the thermocouple which is good in performance can be quickly and safely welded.

Description

technical field [0001] The invention relates to a thermocouple welding circuit and a thermocouple welding device for a detection laboratory. Background technique [0002] Thermocouple is a common detection method for electrical safety testing laboratories to measure the temperature rise of appliances. The basic principle of thermocouple temperature measurement is that two conductors of different materials form a closed loop. When there is a temperature gradient at both ends, a current will flow through the loop, and there will be an electromotive force between the two ends. Because thermocouples have the advantages of simple structure, easy manufacture, and convenient measurement, they can be measured in a wide temperature range from -270 to 2800 ° C, so they are widely used in the field of temperature measurement in testing laboratories. At present, the commonly used methods of welding thermocouples in the laboratory are the contact method and the electrolyte method. The ...

AI Technical Summary

Problems solved by technology

The essence of these two methods of welding thermocouples is that the thermocouple wire is used as the conductor to short-circuit the two-stage power supply, and instantaneous high temperature is generated to weld the two metal wires that form the thermocouple. There are the following disadvantages: 1. The welding current is uncontrollable. It is difficult to form a spherical welded body with a diameter twice the wire diameter at the welding end; 2. Without a protective circuit, it is easy to burn out the power circuit; 3. The electrode of the touch welding method is an easily accessible live part, and the electricity accumulated in the capacitor C does not comply with IEC60065 -1 the requirements of Article 8.1.4;

[0003] The electrolyte method itself uses unsafe extra-low voltage, and the operator is in danger of electric shock

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