Function of the copper tube
Excellent conductivity: copper is the metal with the best conductivity except silver, with extremely low resistance. This minimizes the resistive heat loss generated by the current in the coil itself, ensuring that most electrical energy is efficiently converted into magnetic energy rather than being wasted on coil heating.
Necessary cooling channels: this is the primary reason why they are designed as "tubes" rather than "solid bars". Circulating cooling water (usually deionized water) is provided inside the copper pipe, which can effectively remove the heat and ensure that the coil itself will not be softened, deformed, oxidized or damaged due to overheating, to ensure long-term, stable and reliable operation of the equipment.
Skin effect and tube wall thickness: high-frequency current has obvious "skin effect", i.e. the surface flow of main conductor of current. Therefore, the wall thickness of the copper tube only needs to be slightly greater than the current penetration depth under this frequency. The use of thick wall solid copper material is not only a waste, but also not conducive to heat dissipation. The tubular structure not only ensures the conductive section, but also realizes the material saving and the maximum cooling area.
Good forming and rigidity: the copper has good ductility after annealing, and can be bent and wound into coils of various complex shapes (such as spiral, U-shape, cake shape, etc.) to meet the requirements of different workpieces (such as straight welded pipe, circumferential seam, local heating, etc.). At the same time, it has enough rigidity to keep the shape stable under the action of cooling water and electromagnetic force.
