Why does the pulverizer also have a fever?
Why does the pulverizer also have a fever?
Sometimes we encounter such a problem. Why does a newly installed or used pulverizer with very advanced performance become "hot", parts wear out rapidly, and output drops seriously? This also needs to find the answer from the pulverizer system and use.
The pulverizer system consists of feeding, auxiliary suction, discharge and other parts. Only when these parts match each other well can the pulverizer give full play to its good performance.
The pulverizer generally adopts impeller feeder or belt feeder for feeding. The impeller feeder and belt feeder are both equipped with auxiliary air inlet. The air inlet is properly opened through the adjusting plate, so that when the pulverizer is working, a negative pressure is formed in the crushing chamber, which is conducive to the timely discharge of crushed powder from the screen. If the opening of the regulating plate is too small, the air inlet is not large, the negative pressure in the crushing chamber is small, the powder discharge is not smooth, the powder is excessively crushed, and the heat in the crushing chamber cannot be discharged in time, the pulverizer must have a fever. When the pulverizer has a "fever", the opening of the regulating plate must be checked.
The auxiliary air suction system of the crusher consists of the material settling chamber after crushing, pulse dust remover, fan, etc.
The space of the crushing material settling chamber shall be as large as possible, which is the guarantee of smooth powder path and is conducive to smooth and timely discharge of crushing materials. The small space of the crushing material settling chamber is also the reason for the poor discharge of powder. Therefore, proper space shall be reserved during design to meet process requirements.
The corresponding pulse dust remover shall be selected according to the pulverizers of different models. The type selection of the dust remover shall be determined according to the filtering wind speed, filtering area and checked air volume. To ensure the dust removal efficiency, the air volume of the fan shall be close to the middle value as far as possible, and the air pressure shall not exceed 20% of the design value. It is not allowed to directly install the fan upside down on the air outlet of the dust remover. A powder settling chamber with large space must be set between the dust remover and the material sealing auger, so that the dust concentration of the gas entering the inlet of the dust remover is low. The filter material of the filter bag equipped with the dust remover is mostly polyester needle punched filter felt, with the use temperature ≤ 120 ℃, good acid resistance and poor alkali resistance; For dust particle size ≤ 1 μ m. Or for dust with high moisture content, peritoneal polyester needle punched filter felt can be selected, but it is not suitable for dust with large particle size and large difference in particle size distribution.
The smooth surface of the filter material is suitable as the dust receiving surface: a) for the light dust or the dust containing light impurities; b) Dust with high humidity; c) The dust is viscous and adsorbable; d) Handle the gas with high dust concentration.
The rough surface of the filter material is suitable as the dust receiving surface: a) The dust particle size is small; b) The distribution of dust particle size is relatively uniform; c) The dust humidity is not high; d) The dust has low viscosity and adsorption.
As the hammer of the pulverizer rotates at high speed to strike and rub materials, the moisture and fine dust in the materials will be adhered by the bag of the pulse dust remover, and the wind resistance will increase. With the increase of time, the air volume and pressure of the dust remover will be lost, which will cause the pulverizer to "fever" in serious cases, and the output will decrease. The bag of the dust remover must be replaced or cleaned in time.
The discharge system of the crusher is composed of a material sealing auger, a bucket elevator, etc. The function is to convey the powder passing through the screen to the next process, so as to ensure the continuous and smooth discharge of the crusher. At the discharge end of the auger, there is a material sealing baffle, which is used to ensure the smooth discharge of materials and prevent the wind at the discharge end of the auger from entering the dust remover. Therefore, it is necessary to ensure that the material seal baffle can swing freely. When there is material, the material will jack up the baffle to discharge. When there is no material, the baffle will sag freely, blocking the air at the outlet from being sucked in.
When the pulverizer is working, it is the only correct channel for the air path to let sufficient cold air enter from the feeder suction port and bring the powder out through the sieve plate through the pulverizer chamber. If the installation accuracy is not high and the door, cover plate, air duct and joint are not well sealed, the air circuit will also be short circuited, and the air volume passing through the crushing chamber will be insufficient, causing the pulverizer to "heat up".
Improper use of the pulse controller will reduce the use effect of the pulse dust remover and indirectly cause insufficient air flow through the crushing chamber. The correct method is to set the circuit and the number of injection lines; Pulse width regulation is in the middle; The interval adjustment is in the middle; The use effect of the pulse dust remover is not high. The pulse controller should be checked to adjust the pulse width and interval.
If the oil cup of the oil-gas separator in front of the air bag collects too much oil, the separation effect will decline, and the oil dirt will stick to the filter felt after being blown by the air bag; Or the compressed air pressure is too low (<0.7MPa), which will also reduce the use effect of the pulse dust remover.
If the pulverizer is not used properly and works under overload for a long time, it will also cause the pulverizer to have a fever, or even burn the motor. The correct working condition is that the motor operates at 90% of the rated load.
To sum up, the "fever" of the crusher is caused by insufficient air flow through the crushing chamber due to system problems or improper use; Due to the poor discharge of powder, the material is excessively crushed, which accelerates the decline of output; Due to the poor heat discharge and rapid accumulation, the rotor of the crusher works in a high-temperature and high-speed environment, which aggravates the wear of the hammer knife and pin shaft
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