Induction furnace cooling system
What aspects should be paid attention to when designing the cooling system and pipeline of the induction furnace?
When designing the cooling system and pipeline of the индукционная печь, we should pay attention to the following aspects:
1) Use copper pipes and stainless steel pipes as much as possible for piping materials to prevent rust from entering parts. In recent years, plastic tanks have also been used as cooling water tanks, and plastic pipes that meet pressure resistance requirements have also begun to be used in waterway systems.
2) The diameter of the inlet and outlet pipes should be designed according to the actual inlet and discharge volume. The water inlet pipe is a pressure pipe, and the outlet pipe is divided into a closed return pipe and a self-pressurized return pipe. The former has pressure, and the pipe diameter can be relatively smaller; the latter has no pressure, and the pipe diameter is much larger. The displacement of the quenching cooling medium is discontinuous for the primary quenching parts, while the scanning quenching part lasts for a long time, and the resistance of the filter must be taken into consideration. It has been seen that many quenching machine outlet designs are small, which is related to not taking these factors into account.
3) Avoid contacting the cooling water with the air as much as possible, so as not to reduce the cooling effect of the water due to air bubbles in the water, especially for sensors with high current-carrying densities.
4) The capacity of the induction furnace cooling water tank should be considered according to the specific conditions. Under the condition of a heat exchanger, the minimum cooling tank capacity should also ensure that its capacity can fill the output pipeline and there is still enough storage capacity. The empirical data is required for each 3-4 times cooling water flow per minute.
The larger the cooling water tank capacity, the better the heat dissipation conditions, which can reduce the heat exchange consumption, but occupy more production space.
5) Cooling water temperature control. The inlet temperature of cooling water is not as low as possible, because if the inlet temperature is too low, water droplets will condense on the surface of the cooling element (sweating phenomenon), which will reduce the electrical insulation performance and cause failure. Therefore, the cooling water inlet temperature should be close to room temperature, but not >28°C.
6) The pressure of the cooling water depends on the cooling element and can be regulated by the shunt valve. Generally, sensors have the highest cooling water pressure requirements, while other electrical appliances require lower water pressure. Especially like the oscillating tube of high-frequency equipment for electronic tubes, the anode cooling water pressure is generally greater than 0.12MPa and less than 0.2MPa, etc.. It must be configured according to the instructions. The outlet temperature of the cooling water should also be monitored according to the relevant instructions. Generally, when the temperature rise is too large, it is often a fault state, and the outlet water temperature should generally not exceed 55°C.
7) The heat transfer capacity of the heat exchanger. The heat transfer capacity of the cooling water system heat exchanger is related to the power used, load factor, and efficiency of some components of the equipment. Due to the improvement of conversion efficiency of frequency conversion power supply, such as the efficiency of solid-state power supply is 90% to 95%, therefore, the power of hot plate equipment generated by the equipment is 10% (except for electronic tube high-frequency equipment); bus loss <5%; capacitance loss is about 2%; the quenching transformer loss is 11%-15%; the inductor loss is about 21%; and the power obtained on the workpiece is between 50%-55%.
The cooling water system heat exchanger of the индукционная печь requires a power capacity of 45% of the power supply, while the quenching water system heat exchanger requires a power capacity of 55% of the power supply, that is, a modern frequency conversion power supply of 10OkW. If it is running at full power, the heat exchanger capacity of its equipment cooling water system should be 45kw (38718kcal/h). The heat exchanger capacity of the quenching water system should be 55kw (47322kcal/h). In fact, there are very few cases where the full power is 99% load rate. Therefore, the above capacity should be multiplied by the coefficient K (K<1), determined according to the used power and load rate.
8) The pipe fittings in a system should use the same metal as much as possible, otherwise, the pipe will cause electric corrosion.
9) The piping arrangement of the cooling water system of the induction furnace should be neat, and the turning should be minimized to reduce the resistance. In addition, for the multiple water supply pipes coming out of one distributor, the same length should be sought to make the spray evenly.