Inductors For Through Heating
Aug 12, 2019 News
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Inductors for through heating produced helical to the full voltage of the generator. Since the main objective of the process is to achieve uniform heating of blanks for the entire cross section with temperature drop, not exceeding 100 – 150 C, in contrast to the surface hardening heat will continue tens or hundreds of seconds, depending on the size of the cross section of the workpiece. Due to the fact that the surface temperature reaches at the same time 1200 – 1250 C losses radiation and convention are comparable with the net power, and to reduce them in the inductor is placed thermal insulation. Induct wire inductor consists of a water-cooled shaped copper tube wall thickness is desirable to choose an equal or greater than the depth of current penetration into the copper. The coils are insulated from each other by the winding of varnished cloth or kipernoy tape that is impregnated with bakelite varnish and baked in the thermostat, or best of steklolenty.
Insulation thickness of 1,5-2 mm. Induct the wire to give it hardness pressed between two wooden bars. The ends of the bars with brass studs and crackers attracted to shiferasbestovym slabs 25-40 mm thick. Inductor attached to the ends of printing plates, which are designed to attach to the current supply buses. Go to the inductor coils adjacent Micanite sleeve 1,5-2 mm thick, which serves as electrical insulation. This sleeve is inserted asbestos liner thickness of 2,5-3 mm. In the asbestos liner is the main thermal insulation containing chamotte ring thickness of 10-25 mm or semirings width 100-150 mm, made from fireclay with a mass firing at a temperature of 1300-1600S.
As the lining of the use of solid fireclay pipes is impossible, because they quickly crack and disintegrate. To protect the lining of the mechanical effect of blanks at the bottom of the inductor is put water-cooled rail, welded box-out and flat or concave strips heat-resistant non-magnetic steel. Strip, which are blank, has a thickness of 3-4 mm. The thickness of the box-shaped part of 1,5-2,0 mm. Often at the end of the inductor facing the handling devices, installed with insulated pins short-circuited the shielding ring water-cooled copper tube. In this ring is induced current, whose field is weakened ground field inducer than prevents heating of closely spaced metal parts of the boot device. In inductors designed for heating billets with a diameter up to 75-80 mm, set a guide for large diameters – two or three, sometimes five. If the number of sending more than one, they are often made from cylindrical tube. Currently, quite often the thermal insulation is carried out by pouring induct wires inside and outside the heat-resistant concrete. Before filling induct insulated wire steklolentoy impregnated silicon – organic lacquer. Casting subject to special forms. After the concrete hardens, all parts of the inductor will be firmly fastened, and no structural support elements for mounting is not required. Inductors with thermal insulation from the heat-resistant concrete is relatively easy to use and reliable. However, repairs them is difficult. The thickness of the thermal insulation of concrete must be greater than the chamotte, since the thermal conductivity of concrete more than fireclay in 1,2-1,5 times. This helps to reduce the efficiency of inducer, and therefore sometimes use a combination of isolation. Thickness of concrete on the inside side is determined by the mechanical strength of construction and should be 2-3 mm.
