Structure Introduction
1. Overview
The structure of this electric furnace mainly consists of a furnace body, heating elements, lifting mechanism, rapid cooling device, and temperature control system.
The outer shell of the furnace body is welded from steel sections and steel plates, and the furnace gun structure is constructed with Shandong Luyang aluminum silicate refractory fiber cotton to improve the insulation performance of the furnace body.
The heating element is hung on fiber cotton and fixed with high-temperature resistant porcelain nails.
There is a 10mm thick 304 heat-resistant plate welded into a furnace can inside the furnace, and the processed workpiece is placed inside the can. The upper part of the furnace tank is equipped with drainage and water inlet devices, as well as air inlet devices, which can quickly cool down according to user requirements. Water cooling devices are also installed.
In order to ensure uniform contact between the processed workpiece and the gas, a ventilation fan (Jiangsu made anti-corrosion fully sealed fan) is installed on the furnace shell to force air circulation and achieve uniform temperature and gas inside the furnace. There is a sealing device on the fan shaft sleeve to prevent air leakage, and cooling water is used for cooling.
The lifting of the furnace cover is carried out by the user's own crane through the steel frame installed on the furnace cover.
2. Separate description
A, The furnace body is divided into furnace shell, refractory materials, heating elements, panels, thermocouples, and lead out sockets.
1) The furnace shell is made of various types of steel and steel plates in a cylindrical shape.
2) The furnace is composed of fiber cotton refractory materials, insulation materials, etc. The refractory materials are made of ultra lightweight clay bricks, and the insulation materials include aluminum silicate fiber cotton.
3) The heating element is made of Shougang produced iron chromium aluminum material, wound into a strip and hung on fiber cotton.
4) The panel is made of 45 # steel plate and fixed with screws.
5) One side of the furnace body is equipped with several lead out sockets and thermocouple socket holes.
B, Ventilation mechanisms (sealed anti-corrosion type) are divided into electric motors, blade shafts, bearings, blades, windshields, air release devices, sample devices, panels, and insulation boxes.
1) The electric motor adopts a fully sealed motor.
2) The fan shaft is precision machined from refractory steel material.
3) The bearings are made of imported accessories and have the characteristics of heat resistance and wear resistance.
4) The windshield and air guide system are made of 3mm thick 304 stainless steel.
5) The vent valve is used to discharge the exhaust gas from the furnace tank, and its pressure can be adjusted through the threaded shut-off valve on the exhaust pipe.
6) The sample device is used for sample parts, and the sample tube is made of stainless steel tube welded with a carbon tube jacket to form a sealed water jacket device, which can be used for circulating water cooling to prevent deformation of the sample tube.
7) The panel is made of 35mm steel plate metal processing, and the upper part of the panel is welded with an inclined hammer barrel, which is equipped with a ventilation mechanism. The plane of the inclined hammer barrel is connected to the ventilation fan screw.
8) The insulated box body is all welded with stainless steel material and contains insulation material inside.
8) Equipped with armored thermocouples to test the furnace temperature inside the tank.
C, Heating elements are divided into heating element furnace wire and lead out rod.
1) The material of the heating element is 0Cr25Al5 iron chromium strip.
2) The material of the lead out rod is stainless steel 1Cr18Ni9Ti.
D, The vacuum pump is produced by a domestic famous brand vacuum pump factory, with a complete set of equipment including 2X-70 units, stainless steel vacuum valves, and one flexible pipe joint and rubber hose.
1) The nitrogen pipe is wound in a circular shape from top to bottom of the furnace tank, and several small holes with a diameter of 3mm are drilled on the circular circle.
2) The small tube is welded and fixed in a circle inside the furnace from top to bottom.
Cooling fan: There is a fan for cooling on the outer side of the lower part of the furnace body. When the process requires rapid cooling, press the button on the control cabinet, and the cold air rises along the inner wall of the furnace lining in a tangential spiral shape to carry out heat.
3. Temperature control
The layout of electric heating elements in the furnace is reasonable to ensure uniform furnace temperature. The entire electric furnace is divided into three separate temperature control zones, but at the same time, it is ensured that the heating of each heating zone follows the same process curve.
The control cabinet of the main control system adopts the internationally popular vertical 600 × 1000 × 2000MM
Combination cabinet. Spray paint on the exterior of the control cabinet. The electronic control panel is equipped with ammeters, voltmeters, temperature controllers, temperature recorders, and control switches.
The temperature control main circuit is triggered by a high-power power regulator and voltage regulator, using air cooling, and equipped with overload, overheating, and overcurrent protection functions. This adjustment function is divided into automatic and manual modes, and the automatic mode can form an automatic temperature control process with the temperature control meters in each zone. Manually disconnect the temperature control instruments from each zone and adjust the power of each zone manually. There are functions such as limiting heating power in automatic or manual mode. The temperature control instrument adopts advanced SRS13A series high-precision digital PID self-tuning instrument from Shimada Electric Company in Japan, which has multi range input, arbitrary temperature setting, and multiple alarm functions. The temperature signal is received through a thermocouple, and the millivolt signal is amplified and converted. The digital display instrument outputs a 4-20mA current signal, which is then adjusted by a thyristor power regulator to control the pulse number of the thyristor with an accuracy of ± 1 ºC. This temperature control is equipped with thermocouple correction function, power limiting function, and over temperature alarm function.
The furnace temperature is recorded using a paperless recorder, which provides real-time curves, prints, and records the temperature during the heating and insulation time process. At the same time, it monitors the main heating circuit and effectively monitors the entire production process. It can also be used as an archive for the heat treatment process of workpieces or handed over to users for practical theoretical basis.
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