How to Use a Muffle Furnace?

How to use a muffle furnace?

Tube Furnace
Tube Furnace
  1. The electric furnace does not need special installation, it only needs to be placed flat on the indoor floor or bench. The controller should be placed on the workbench, and the inclination of the workbench should not exceed 5 degrees. The minimum distance between the controller and the electric furnace shall not be less than 0.5 meters. The controller should not be placed on the electric furnace, so as not to affect the normal operation of the controller.
  2. The load capacity of the power cord, switch and fuse connected to the controller and the electric furnace should be slightly larger than the rated power of the electric furnace. A thermocouple is inserted into the furnace with 20-50mm, and the gap between the hole and the thermocouple is filled with asbestos rope. It is better to use compensation wire (or insulated steel core wire) to connect the thermocouple to the control. Pay attention to the positive and negative poles, and do not connect them in reverse.
  3. When wiring, first loosen the screws on the left and right sides of the controller shell, then turn the cover up, and connect the power cord. The connection between the controller and the electric furnace and the thermocouple connection line (compensation wire is best). Insert the thermocouple into the furnace from the small hole of the thermocouple holder, and block the gap between the hole and the thermoelectric with asbestos rope, and then fix it. (Note: The phase and neutral of the power supply cannot be reversed. For safe operation, both the controller and the electric furnace must be reliably grounded)
  4. After checking that the wiring is correct, you can turn on the power. First, turn on the power switch, then pull the toggle switch on the controller panel to the open position, adjust the setting button, and set the temperature to the degree you need. If pull the setting switch to the measurement position, the red light is off (NO), and there is also the sound of the contactor. The electric furnace is energized, the ammeter indicates the heating current value, and the temperature rises slowly with the increase of the temperature in the furnace, which indicates that the operation is normal.

When the temperature rises to the set required temperature, the red light is off (NO) and the green light is on (YES), the electric furnace is automatically powered off and the temperature is stopped. Later, when the temperature in the furnace drops slightly, the green light is off, the red light is on, and the electric furnace is automatically energized. Repeatedly, the purpose of automatically controlling the temperature in the furnace can be achieved.

  1. In order to check whether the broken couple protection device is working normally, the method is: loosen one end of the thermocouple, and the temperature measurement indicator will quickly rise to the highest point and the heating power supply will be automatically cut off. The broken couple device is good, reconnect the thermocouple, and it can work normally.
  2. Bake oven. When the electric furnace is used for the first time or used again after a long period of inactivity, it must be oven baked. The process is as follows:

When the room temperature rises to 200℃ for 4 hours (open the furnace door to let water vapor escape)

When 200℃ to 600℃ for 4 hours (close the furnace door)

When 600℃ to 800℃ for 2 hours (close the furnace door)

After use, first pull the toggle switch on the control panel to the off position, and then cut off the main power switch.

Precautions for using muffle furnace

Rotary Tube Furnace
Rotary Tube Furnace
  1. When in use, the maximum furnace temperature must not exceed the rated temperature, so as not to burn the heating element. It is forbidden to pour various liquids and easily soluble metals into the furnace. The muffle furnace is best to work below the maximum temperature of 50℃, at this time, the furnace wire has a longer life.
  2. The muffle furnace and controller must work in a place where the relative humidity does not exceed 85%, and there is no conductive dust, explosive gas or corrosive gas. When metal materials with grease or the like need to be heated, a large amount of volatile gas will affect and corrode the surface of the electric heating element, causing it to be destroyed and shorten the life. Therefore, the heating should be prevented in time and the container should be sealed or properly opened to remove it.
  3. The muffle furnace controller should be limited to use within the ambient temperature range of 0-40℃.
  4. According to the technical requirements, regularly check whether the wiring of the electric furnace and the controller is in good condition, whether the pointer of the indicator is stuck or stagnated when moving, and use the potentiometer to verify the meter due to magnetic steel, demagnetization, wire expansion, and shrapnel Increased error caused by fatigue, balance failure, etc.
  5. Do not pull out the thermocouple suddenly at high temperature to prevent the jacket from bursting.
  6. Keep the furnace chamber clean and remove oxides in the furnace in time.
  7. The working environment requires no flammable materials and corrosive gases.
  8. In order to ensure safe use, the ground wire must be installed and well grounded.
  9. When using, the furnace should be turned off lightly to prevent damage to the parts.
  10. When taking samples in the furnace chamber, turn off the power first, and handle with care to ensure safety and avoid damage to the furnace chamber.
  11. In order to prolong the service life of the muffle furnaceand ensure safety, samples should be taken out of the furnace in time after the equipment is used, withdraw from the heating and turn off the power supply.

Safe Maintenance

Tube Furnace
Tube Furnace
  1. The power must be cut off before maintenance or inspection.
  2. If the muffle furnace body is damaged, please stop using it. If the product body is damaged and used continuously, it may cause accidents such as fire and electric shock.
  3. Only qualified personnel can replace parts. It is strictly forbidden to leave thread or metal objects in the equipment, otherwise there is a danger of explosion and fire.
  4. After replacing the instrument or circuit board, the parameters must be adjusted and matched before operation, otherwise there is a danger of property damage.
  5. The control circuit part of the equipment should be inspected regularly (checked once every six months), and the wiring should be tightened. If there is any disconnection of the insulation layer or the wiring of the wiring, it should be dealt with in time, otherwise it will cause a short circuit of the equipment or a fire hazard.

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