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Application of box-type electric furnace in laboratory

Time:2020-09-18 09:30 Click:
  The main purpose
 
   The laboratory box-type resistance furnace is mainly used in the laboratories of colleges and universities and scientific research institutions to do ceramics, metallurgy, electronics, glass, chemicals, machinery, refractory materials, new material development, special materials, building materials, powder baking, ceramic sintering, high temperature experiments, For material handling and quality inspection.

working principle

The thermocouple converts the furnace temperature into a voltage signal and adds it to the microcomputer temperature control regulator. The regulator compares this signal with the programmed setting and outputs an adjustable signal. The adjustable signal is used to control the trigger, and the trigger triggers the voltage regulator to achieve the purpose of adjusting the voltage and temperature of the electric furnace.
electric furnace
The main structure

The laboratory box-type resistance furnace is mainly composed of furnace body, furnace, heating element, temperature measuring element, control instrument and so on.

Kejia laboratory box type resistance furnace
 
1. The shell of the electric furnace body is made of plastic spraying, which has the characteristics of temperature resistance, durability, oxidation resistance, acid and alkali resistance: the furnace body adopts an advanced air-cooled double-layer furnace body structure, and an effective air-cooled guide partition makes the furnace shell The whole cold air is circulated, and the conductive sheet of the heating element is finally cooled and discharged from the furnace body, which avoids the high temperature oxidation of the conductive sheet of the heating element and ensures a good working environment.
 
2. Furnace: It is made by assembling method to avoid the phenomenon of rapid heat and cold cracks.
 Furnace material:
 (1) Furnace inner wall: high-temperature fiberboard or high-temperature bricks, carefully constructed by multiple pieces, it has special effects such as high temperature resistance, acid and alkali resistance, oxidation resistance, not easy to crack, long service life, slow heat conduction, energy saving, unique furnace design, durable Durable, non-collapsing, (choose refractory interior wall materials with different signals according to the furnace temperature) use ceramic fiber materials such as ordinary aluminum, high aluminum, high aluminum and zirconium for insulation, high temperature resistance, low heat conduction, and no pollution (select insulation according to different temperatures Material) high temperature felt or nanofiber board, (choose insulation material according to different temperature)

(2) Middle layer insulation: use ceramic fiber materials such as ordinary aluminum, high aluminum, high aluminum and zirconium for insulation, high temperature resistance, low heat conduction, and no pollution (choose insulation materials according to different temperatures)

(3) Outer insulation: high temperature felt or nanofiber board, (choose insulation materials according to different temperatures)
 

3. Heating element:

(1) Resistance wire: The resistance wire has a large surface load and good oxidation resistance. The A1203 film formed after oxidation has good chemical resistance and high resistivity, high resistivity, good sulfur resistance, and high strength at high temperatures. It is non-magnetic and has good corrosion resistance except for sulfur atmosphere.

(2) Silicon carbide rod: It is a recrystallized body of silicon carbide that is made of silicon carbide into a rod or tube. High hardness, small deformation, resistance to rapid cold and heat, no reaction with acidic objects, anti-oxidation, use with 1400 degrees electric furnace. The old and new rods should not be mixed, and the resistance value will increase after long-term use. Replace with new silicon carbide rods when necessary.

(3) Silicon molybdenum rod: It is made by powder metallurgy. The surface can be formed into a layer of oxide film at high temperature. The oxide film forms a protective layer. It is resistant to oxidation and corrosion. It is suitable for electric furnaces at 1200-1800°C and is hard at room temperature. However, it is brittle and should be handled carefully. It becomes soft and extensible above 1350℃. Avoid contact with the furnace and furnace bottom, so there should be a certain distance from the furnace and the furnace bottom when installing. It has a certain degree of resistance to rapid cold and heat. The most prominent advantage is that in addition to the high heating temperature, it also has the characteristics of anti-aging and the new and old rods can be mixed.
 
4. Temperature measuring element:

Class K: The applicable temperature is 0-1200 degrees. The materials are nickel-chromium and nickel-silicon.

S grade: applicable temperature is 0-1600 degrees, the material is platinum rhodium 10 and pure platinum,

Class B: The applicable temperature is 0-1800 degrees, and the materials are platinum rhodium 30 and platinum rhodium 6.

Control instrument: adopts fully intelligent 50-segment ID control temperature controller. The temperature controller is a dual-line LED display dial, which is mainly used for temperature control, sensitive response, heat preservation, and cooling temperature curve, unattended, PID control, with deviation, Over-temperature power-off alarm and other functions make the consistency and reproducibility of any test or experiment possible. It has automatic constant temperature and time control functions, and is equipped with a secondary over-temperature automatic protection function, which is reliable and safe to use. It can display temperature, temperature section number, section time, remaining time, output power percentage, voltage, current, etc.

Operation method

(1) The appearance of the furnace must be inspected before use to check whether the furnace body is damaged, deformed, whether the furnace door is closed in place; whether the heating element is damaged; whether the electrical components are intact, whether the wiring is correct and secure, and whether the grounding is good. The problems found should be resolved in time.

(2) Open the side panel of the electric control box and connect the power supply firmly (220V/380V)

(3) Clean the furnace, (during transportation, there may be a small amount of powder in the furnace), put the materials into the furnace (using crucibles, pads and other high-temperature tools or containers) and put the door plugs on (the low-temperature furnace is not equipped with Belt) After gently closing the furnace door, lock the furnace door.

(4) Press the power button and wait a few seconds (according to the detailed operation instructions of the instrument) to program.

(5) Check a series of procedures such as heating, heat preservation, and cooling, and confirm that they are correct.

(6) Press the heating button, and then press the instrument plus key for three seconds to start (see the separate manual for specific instruments)

(7) Manual shutdown, first press the minus button and then press the SET button, release when SV is 0, the meter will shut down (automatic shutdown can be omitted)

(8) Press the stop button again, (if there are two switches, press the heating button to reset the heating button)

(9) Wait until the electric furnace is below 500℃, then turn off the power button.

Precautions

1. The place where the equipment is placed should be well-ventilated, free of vibration, and free of flammable, explosive gas or high dust.

2. Please use the power supply that matches the purchased equipment. Connect the grounding protection wire reliably. Do not introduce high voltage to avoid damage to the instrument and control circuit. Please turn off the power when not in use.

3. After the inspection, power on and test the machine, please use the power supply voltage that matches the purchased equipment, connect the grounding protection line reliably, and do not introduce high voltage to avoid damage to the instrument and control circuit. If not in use, please turn off the power.

4. When connecting the power supply, please pay attention to the marked A (+) N (-) wire number, A (+) live wire, N (-) neutral wire, and the shell is grounded.

5. Please power on and test the machine after installation.

6. When the oven is used for the first time or is not in use for a long period of time, the official opening money must be carried out as required.

Contact Information

E-mail:
web@kejiafurnace.com
Address:
No.18 Hongye Road, Hi-tech zone , Zhengzhou, China, 450000
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181-3719-5600

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