Introduction of main structure and performance of vacuum brazing furnace
Horizontal cylindrical furnace body, both ends open, square metal screen heating chamber, external circulation cooling system, diffusion pump vacuum unit.
1. Furnace door opening: pneumatic opening and locking structure.
2. Furnace body: horizontal cylindrical furnace body, water-cooled double-layer structure, in which the inner wall is made of stainless steel. Open the door at both ends, one end is the charging door, the hydraulic opening and locking is tight, and the other end is the maintenance door.
3. Heating chamber (furnace hearth): square all metal screen heating chamber, six side heating, good temperature uniformity.
3.1. Four layer all metal screen insulation structure is adopted. The material of heat shield is 304.
3.2. The heater adopts nickel chromium strip.
3.3. The heating chamber frame is made of stainless steel.
3.4. The support frame is made of heat-resistant steel.
3.5. In order to ensure the temperature accuracy of workpiece brazing, the heating chamber is designed to be controlled independently by multiple heating zones.
3.6. The insulating parts are high purity alumina ceramics.
4. Cooling system:
In the external circulation air cooling mode, the fan and heat exchanger of the cooling system are placed outside the welding vacuum room to reduce the moisture absorption in the furnace and improve the evacuation speed.
4.1. The special motor for vacuum furnace is adopted (it is allowed to be used under the condition that the temperature does not exceed 180 ℃ and the pressure is higher than 0.05Mpa).
4.2. high finned copper tube heat exchanger (copper tube, aluminum fin)
5. Vacuum system:
5.1. Diffusion pump, roots pump, mechanical pump three-stage pump system, diffusion pump inlet with anti return oil cold trap, and equipped with maintenance pump.
5.2. The valve is equipped with spare gauge socket; a leak detection point is set at the front end of mechanical pump and roots pump
5.3. The vacuum system is equipped with high efficiency cold trap and filter.
5.4. In order to increase the pumping speed, the unit is equipped with two sets
6. Electric control system:
6.1 the temperature control of vacuum furnace is composed of touch screen, Japanese programmable temperature controller, thyristor voltage regulator and “K” thermocouple. Several imported temperature control meters operate in coordination through set value communication. In addition, several thermocouples can be connected to the temperature inspection instrument to monitor the temperature values of different parts of the workpiece.
6.2 vacuum control: the high and low vacuum degree in the furnace is measured by the composite vacuum gauge, and the vacuum gauge displays the measured value and outputs the signal to PLC to control the vacuum system.
Range: from atmospheric pressure to limiting vacuum degree
6.3 fast cooling control: automatically (or manually) fill the furnace with protective gas, start the fan to make the gas rapidly cool between the furnace body and the heat exchanger. The fast cooling cycle can adjust the cooling rate by controlling the inflation pressure.
6.4 automatic and manual control of working process: PLC (model FX2N) of Mitsubishi company of Japan is adopted. The whole working process of the equipment is interlocked and controlled. Safety interlock protection and automatic treatment measures are provided for vacuum, temperature, gas pressure, cooling water pressure and misoperation in the furnace. With sound and light alarm, the equipment can work automatically and manually, and can be switched at any time. For example: (1) the vacuum degree is not qualified and cannot be heated; (2) if the water pressure is low, the heating power supply of welding room and diffusion pump can be cut off; (3) when the temperature is over, the heating power supply will be automatically turned off
6.5 multi channel liquid crystal paperless recorder is used for field process record of vacuum furnace, with large capacity memory and long-term data storage. Trend curve, bar chart, large screen real-time value and other display modes are adopted. Data interface is configured to facilitate data storage and transfer.
6.6 all low voltage electrical appliances are domestic famous brand and joint venture products. The tested products with high reliability are equipped with large display screen reflecting the working state of the equipment
7. Water cooling system
The water cooling system is equipped with water pressure monitoring alarm, flow control valve and water flow indicator. The main pipeline is made of hard steel pipe, and the pipeline is connected with tap water branch, in case of circulating water failure or special circumstances.
8. Workpiece conveying system:
It is composed of a track and a feeding car. The feeding car completes the lifting of the workpiece through the hydraulic mechanism.
9. other parts of the equipment include: inflation system, workpiece temperature measurement device, pneumatic device, etc.