Main structure of vacuum brazing furnace
Vacuum brazing furnace host is horizontal, single structure of indoor heating, consists of furnace body, heating chamber, vacuum system, air system, air system, pressure
system, water cooling system and electric control system, etc.
1. Main body of vacuum furnace
The main body of vacuum furnace consists of furnace body and heating chamber. The shell of furnace shell, furnace door and motor cover are all welded by double shell, double oval head and air-tightness welds for flange. The water channel is between the two layers of tube body, and the cooling water is passed in. The cover is made of a locking ring. The heating chamber is designed to be cylindrical, with a heat shield consisting of a frame and graphite felt.
2. Heating system
The heating system includes heating power, temperature control system and heating elements. Magnetic voltage regulator is selected for heating power supply, and its voltage regulation is controlled by dc excitation. Closed-loop control is realized according to different control signals. Dc excitation power is controlled by two-way thyristor. Temperature control instrument with a self-tuning function, thermocouple convert the temperature inside the furnace into electrical signals, to detect the temperature of the difference between the current value and set value, after the PID operation as the output signal, control of bidirectional thyristor conduction Angle, so as to effectively control the average heating power of heating element, the furnace temperature and setting the heating curve is consistent. The heating element is 18 graphite tubes, which are uniformly distributed along the circumference of the hot zone by triangle connection method, so as to provide good uniformity of furnace temperature. The heating element is connected to the external wiring by three water-cooled electrodes.
3. Vacuum system
The main pump of the unit is kt-500 diffusion pump, and the former pump is zj-600 roots pump and 2X-70 rotary plate mechanical pump. It is equipped with high vacuum valve, main valve, bypass valve and electromagnetic differential pressure valve connected with mechanical pump. The mechanical pump is a crude vacuum device, and the later stage of the mechanical pump is connected with roots pump. However, only when the pressure in the pumping system reaches the allowable inlet pressure of the roots pump can the roots pump start to work, otherwise it will be damaged due to overload and overheating. The diffusion pump is a high vacuum device. It diffuses the gas molecules in the vacuum system into the jet stream of high speed oil and steam, and it is discharged into the air by the front pump to complete the pumping action.
4. Air cooling system
In vacuum furnace main body of the machine, and is equipped with 1 three-phase asynchronous motor, gas by heat exchanger to reduce temperature after the dome, through every hot into the furnace inlet, impeller workspace, then return to the radiator, implementation of the circulating cooling.
5. Water cooling system
The water cooling system consists of stainless steel globe valve, inlet, drain tank, hydraulic and electrical contact pressure gauges, etc. The inlet is provided with 63.5mm(5in) stainless steel ball valve and 101.6mm(4in) flange at the outlet. It only needs to be connected to the user's circulating water system interface.
6. Partial pressure system
The partial pressure system consists of electromagnetic vacuum valve and adjustable needle valve. When partial pressure control is required in copper brazing process, high purity nitrogen or argon gas can be filled in.
7. Inflating system
The inflating system consists of chase diameter inflating stop valve, collecting gas bus-bar, vacuum electric contact pressure gauge, etc.