Introduction to the muffle furnace and precautions for use

Classification of muffle furnace

The muffle furnace is divided into domestic muffle furnace and imported muffle furnace according to nationality. According to the heating element, there are: electric furnace muffle furnace, silicon carbon rod muffle furnace, silicon molybdenum rod muffle furnace; according to the rated temperature, the general classification is: 900 degree series muffle furnace, 1000 degree muffle furnace, 1200 degrees Muffle furnace, 1300 degree muffle furnace, 1600 degree muffle furnace, 1700 degree muffle furnace. According to the controller, there are the following types: pointer table, ordinary digital display table, PID adjustment control table, program control table; according to the insulation material to distinguish: ordinary refractory brick and ceramic fiber. Therefore, the user must clearly understand the contract when purchasing the product, so that the supplier is not tired.

Muffle furnace structure and parameters

The muffle furnace is divided into two parts: the furnace body and the intelligent controller. Some muffle furnaces are integrated with the furnace body and the controller, while others are separated by the two.

The muffle furnace is mainly heated by electric furnace wire, which is divided into two-side heating, three-sided heating, etc.; the ordinary brick structure of the muffle furnace is heated at a slower speed, and the ceramic fiber structure is light in weight, and the heating rate is fast, saving energy. At the same time, the service life has also been improved. There is also a controller, a little bit is pointer-type, by manual reading, and more is intelligent control, temperature control is more accurate than pointer-type temperature control accuracy, reducing the error of visual reading and human operation; There is also a good temperature sensor

The most basic parameters of the muffle are the volume and the maximum temperature range:

Commonly used muffle furnaces have volumes of 4, 6, 10, 22, 30, and 45 L. The common maximum temperatures of domestic muffle furnaces are 1000 ° C and 1200 ° C.

Application range

Muffle furnace cycle operation type, for laboratory, industrial and mining enterprises, scientific research units for elemental analysis and determination of general small steel parts quenching, annealing, tempering and other heat treatment, high temperature Mafu furnace can also be used for metal, ceramic sintering, dissolution , analysis and other high temperature heating.

(1) Thermal processing, cement, building materials industry, thermal processing or processing of small workpieces.

(2) Pharmaceutical industry: used for the inspection of medicines, pretreatment of medical samples, etc.

(3) Analytical chemical industry: As a sample treatment in the fields of water quality analysis and environmental analysis. It can also be used to carry out oil and its analysis.

(4) Coal quality analysis: used to determine moisture, ash, volatile matter, ash melting point analysis, ash composition analysis, elemental analysis. It can also be used as a general ashing furnace.

Safe operating procedures and cleaning of muffle furnace

1. The safe operation of the muffle furnace:

(1) Before opening the furnace, check the tightness of the gas pipeline valve and the pressure on the gas pipeline should not be lower than the specified value.

(2) Working condition of the empty furnace test push rod mechanism, tie rod mechanism and lifting mechanism.

(3) Loosen the compression spring to the specified size range.

(4) Adjust the water level of the water seal, open the valve through which the water seal is discharged, and close the valve through the water seal.

(5) Close the furnace door at the feeding end, open the furnace door at the discharge end, and close the furnace door when the kerosene is sprayed out to form a misty flow.

(6) Point the burner of the feed chamber.

(7) Exhaust gas should be discharged through a valve that does not pass through the water seal.

(8) Intermittent production First, the furnace can be carburized.

(9) When the part is placed, the distance between the part and the part is not less than 5 mm; the edge of the part does not exceed the length of the bottom plate and the specified height.

(10) To quickly switch the feed door and the discharge door, but the speed of the push-pull rod should be stable.

(11) The position of the part in the pre-cooling chamber should be opposite to the underside of the thermocouple.

(12) Only 24 chassis can be filled in the furnace, and the feeding must be pulled first and then pushed.

(13) When the furnace is shut down, the furnace zone should be lowered to the same temperature, and then the natural cooling will begin.

2. Muffle furnace equipment cleaning:

(1) The furnace tank should be cleaned once a week during continuous production, and the cleaning of the intermittent production tank should be carried out immediately after stopping the furnace.

(2) When the furnace cleaning temperature is 850 ~ 870 °C, the chassis should be taken out;

(3) When blowing from the feed end of the furnace with a compressed air nozzle, the valve should not be opened too much, and must be moved back and forth, left and right to prevent local overheating;

(4) The gas burner is cleaned once with kerosene before carburizing.

(5) After quenching the chassis or fixture, return to the pre-cooling chamber to remove oil.

(6) It is found that the exhaust pipe is blocked (the pressure in the furnace suddenly increases) and should be cleaned up immediately. First open the exhaust valve that does not pass the water seal, and then close the exhaust valve of the water seal. After cleaning, open the exhaust pipe valve of the water seal first, and then close the exhaust valve without water seal.

Muffle furnace maintenance and precautions

1. When the muffle furnace is used for the first time or after long-term deactivation, it must be oven-dried. The oven should be at room temperature 200 ° C for four hours. 200 ° C to 600 ° C for four hours. When using, the furnace temperature should not exceed the rated temperature to avoid burning the heating elements. It is forbidden to infuse the furnace with various liquids and easily soluble metals. The muffle furnace is best to work below 50 °C below the maximum temperature, at which time the furnace has a long life.

2. The muffle furnace and controller must work in a location where the relative humidity does not exceed 85% and there is no conductive dust, explosive gas or corrosive gas. When a metal material such as grease is required to be heated, a large amount of volatile gas will affect and corrode the surface of the electric heating element to destroy and shorten the life. Therefore, when heating, it should be prevented and sealed in a timely manner or properly opened to eliminate.

3. The muffle controller should be limited to use in the ambient temperature range of 0-40 °C.

4. According to the technical requirements, regularly check whether the wiring of each electric furnace and controller is good, whether there is any stuck stuck phenomenon when the indicator pointer moves, and use the potentiometer to check the instrument due to magnetic steel, demagnetization, wire drawing, and shrapnel. The increase in error caused by fatigue, balance damage, and the like.

5, the thermocouple should not be pulled out at high temperature to prevent the jacket from bursting.

6. Always keep the furnace clean and remove the oxides in the furnace in time.