Reduction measures temperature welding clamp handle

 

  (Tianjin Internal Combustion Engine Manufacturing Branch, Tianjin 300100)

 

    Welding clamp plier handle temperature is the most important technical indicators component. In actual use, if welding clamp handle is too hot, the welder can not continue to use the forced interruption welding. Welding clamp in use, the conductor and the connection parts of the temperature is high, however, to use a direct impact on the appearance and the temperature rise or the handle. Had made two sizes (300 A, 500 A) of more than 30 of the welding tongs for temperature rise test. The 'root 2m long cable with a conductor welding clamp tightly connected with the' block 100 mm × 100 mm x4 mm mild steel rust-free, and its 'end with welding clamp clamping jaw, and the other' end of the load current shorted. This method is relevant IEC standard test methods' cause. Welding clamp being tested through the current, when the temperature rises to a constant value, the measured temperature of the handle. Determine the value of the constant rise in temperature to stabilize the load when the latter 'period and before the' cycle f every 5 min for the 'cycle) and to maintain compared to' cycle, temperature does not exceed 1 ℃. Appearance and choice of thermocouple measured on the handle. When tested with as little putty hot junction of the thermocouple to be fixed.

 

    Collected from domestic welding clamp perspective, mostly wafer, the basic structure 'cause. From a structural point of view, the front portion of the handle higher temperatures, and because of the conductor and the handle bore misalignment arise handle external radial temperature uniformity. To obtain welding clamp axial, radial real data, four thermocouples were distributed in the groove of the handle, and then another four thermocouples were distributed in the handle Polonium Trail.

 

    The results, along the axial handle forward after the temperature rises. Welding tongs exist in actual use workpiece radiant heat transfer through the back electrode, welding clamp white body resistance heat generated. The welding tongs white body temperature rise is caused by the resistance level of the main 'ring, white body resistance welding tongs tripartite and consists of: clamping jaws contact resistance at the cable wiring to the resistance of the conductor itself resistor. Therefore, the need to change the cable tight line parts of the connection to the connection resistance is small, and the connection is solid and reliable; optional lower resistance conductor; increased conductor section area; increase in contact area as strong jaws.

 

    Table 1 shows the different handle sizes temperature test results. Seen between the conductors inside the handle hole and have 'given clearance. The larger the gap, thereby release the current through conductor the greater the heat generated by the conduction of heat to the handle to reduce their appearance. Tested and analyzed to determine the improved welding clamp structure, reducing the temperature of the handle measures:

 

    (1) Select the appropriate cooling clearance appropriate to reduce the length of the conductor, the conductor section area increases. I plant in 1981 produced before 500 A welding clamp, handle temperature at 53 ℃ or more. Improved design, the handle hole and the appropriate increase in the cooling gap between the conductors, the handle tables met the standard temperature, while reducing the consumption of copper. In 1984, the appraisal industry, I plant the production of 500 A welding clamp lowest temperature. Each of the welding tongs original copper 186 g, the improved copper 153 g, according to an annual output of 300,000 welding tongs calculation, the copper section of about 10 t.

 

    (2) use of air-cooled structure. Designed to be air-cooled structure: the tail into the air to handle by the front of the handle through the heat vent. The existing types of welding clamp a little improvement, we can achieve a good effect cold indeed.

 

    (3) water-cooled structure. In the air-cooled welding clamp, based on the intake pipe to the inlet pipe, plus the return pipe. This improvement in the conductor and the handle was placed between the inner hole into the return pipe can also be added to the circulating water in the hole conductor. After water cooling, the temperature decreased significantly.

 

    (4) change the cable connection. Use special wiring Bu, greatly reduce the contact resistance value so the welding tongs temperature greatly reduced. Using cone up core type connection. Widespread use of foreign welding clamp type A, in which the cone rose pin connector. The cable penetration sleeve, through the cone and thread the cable tight connection wire core tensioner. It features a large plot connecting portion in contact, the contact resistance is extremely small, solid and reliable connection, use a lower temperature.