How to control the heating of molybdenum wire furnace

How to control the heating of molybdenum wire furnace

Temperature coefficient of resistance of tungsten and molybdenum materials is opposite bigger, low-temperature resistance is small, therefore made of tungsten and molybdenum materials do resistance furnace heating element in the process of cold heat, if do not use appropriate control method to produce excessive current and damage to equipment.
At present, the main component of the voltage and current control in the heating and insulation of the electric furnace is the thyristor, the fatal defect of silicon controlled is the overcurrent and the over-voltage difference.In tungsten molybdenum wire of electric furnace, the wire resistance rate at low temperatures is small, easy to produce the flow, so how to guarantee under the premise of the production process to avoid appear over current at low temperatures is of vital importance.According to many years' research and engineering practice of the author, the temperature coefficient of resistance of the larger tungsten molybdenum wire of electric heating can use manual piecewise constant pressure heat up, automatic segmentation pressure limiting temperature and pressure limiting current limit of the double closed loop heat three methods, but can not only meet the current and can meet the requirements of heating process.
Furnace in the first place at a certain temperature heating rate and the targets set by the first paragraph, because of the furnace and furnace heat absorption and heat diffusion, reaches the set temperature when the heating power and cooling rate balance, electric furnace in the process of thermal insulation, temperature in thermal process control system with proper power to maintain constant temperature control of electric furnace.Then, further increase the temperature of the heating voltage, the heating power of the electric furnace is raised, and the electric furnace enters the next phase of warming.