Repair of laboratory electric furnace failure

Repair of laboratory electric furnace failure

The heating body will become soft, swell, fall, fall and overlap first, and then fuse (melt) after the heating body works for a long time. In order to make the furnace wire have a certain strength at high temperature and prevent softening, collapse or sagging, the structural size of the furnace wire must be designed first, such as spiral resistance wire, and attention should be paid to the diameter of the alloy element, the pitch and the pitch diameter of the spiral. The heating body should be installed close to the furnace lining, and should be placed flat on the bricks, leaving proper space for expansion. The position of the small hook should be appropriate, generally 400~600mm, and it can be firmly hooked to prevent it from falling down. In addition, in order to prevent contact between the furnace wires, spacers should be used. Can be used to isolate the resistance wire made of high temperature resistant materials such as 95 porcelain to prevent overlapping. In particular, the transition between the brick layer and the layer in the furnace (when building the furnace, there is generally a 50mm gap between the brick and the front and rear walls for the turning and installation of the resistance wire), which should be pre-padded with ceramic chips or furnace wires Put on the porcelain tube (the porcelain tube should be pushed to the top). High-temperature furnaces cannot use diatomaceous earth brick saw slices to be placed in the middle of the furnace wire. Because diatomaceous earth bricks are poor in heat resistance, they can only be used below 900 ℃, and they are easy to dissolve and deteriorate in high-temperature furnaces.

For the furnace wire that tends to fall down, check whether the small hook of the furnace wire is working (the hook of the resistance ribbon must be firmly built, pressed, plugged, and not loose), and the furnace wire can be changed by gas welding or torch baking. Soft, then restore its original shape and size, and put a porcelain tube in the furnace wire (a mandrel can be worn in the porcelain tube), etc. If two porcelain tubes are used at the same time, the ends of the porcelain tubes must be close together.

The heating body can be directly welded to repair the general broken ends. For the serious collapse, can not be straightened, and the local overburned part is seriously damaged, the method of replacing a section can be generally used. It is not necessary to scrap the whole set because of partial failure. The material, diameter, pitch and length of the resistance wire for repair welding must meet the original technical requirements. The newly repaired resistance wire must not have defects such as cracks and rust, and must be uniformly dense. When using the old resistance wire, the resistance wire should not have obvious uneven thickness, oxidation corrosion, crack deformation, aging and brittleness.

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