There are some problems in the production of air crushing process and the safety measures in the operation of air crushing equipment
Air Mill, also known as Fluid Energy Mill (Fluid Energy Mill), or jet mill (et Mill), is an efficient ultrafine grinding equipment. Different from the principle of the specialized mechanical crusher, it uses the huge kinetic energy generated by the high-speed air flow generated by the high-pressure gas through the nozzle, so that the material particles impact each other, or impact with the fixed plate (such as the impact plate), to achieve the purpose of crushing. Because the uncaptured dust particles in the sample crushing process have a suitable particle size and distribution state: the general particle size is less than 5um, and the dispersion stability in the air is good, and it is easy to reach the explosion limit.
Noise problem
Research and production practice have shown that the higher the airflow speed, the finer the product obtained. When ultrafine products are obtained, the speed of the air flow must be supersonic. In order to obtain finer products, people have increased the speed of the air stream to 2-5 Mach numbers. However, with the increase of air speed and Mach number, the noise generated by high-speed air flow increases, especially for the direct discharge and feed disc air mill when the air speed exceeds 3 Mach number, the actual value of the noise near the discharge port is more than 130 dB(A), which seriously affects the physical and mental health of the operator, so that the hearing is haute, palpation, etc. And this kind of hearing damage is not reversible. Noise makes people can not concentrate, attention is distracted, often easily lead to accidents. Due to the special structure of the air mill itself, that is, the exhaust port is used for the discharge of high-pressure gas and the discharge of ultrafine powder products at the same time, so the design of the muffler is required to reduce the noise and does not affect the discharge, which puts forward very strict requirements for the structural design of the muffler. At present, multi-stage cyclone separators, large dust removal equipment and auxiliary equipment such as exhaust fans are usually connected at the discharge port.
Safety problems of ultrafine powder produced by air mill
Including respiratory pneumoconiosis and dust explosions. The particle size of the dust obtained by the air flow grinder is basically below 5um, and the dust below 5um is the most harmful to the human body. Therefore, the chance of pneumoconiosis occupational disease will be significantly increased by the use of air pulverizer. At the same time, dust is dispersed in the air on a large scale to form dust clouds, and dust explosions may occur. Because the dust particles captured at the end of the sample crushing process have a suitable particle size and distribution state: the general particle size is less than 5um, and the dispersion stability in the air is good, and it is easy to reach the explosion limit. The consequences of dust explosions are also extremely serious.
If there is enough combustion-supporting air around these particles and it has its minimum ignition energy, then it is easy to have a dust explosion. Moreover, the shock wave generated by the local dust cloud explosion causes a large amount of deposited dust to fly and mix with the air, and may form a secondary explosion. Because the dust explosion has the characteristics of large energy, serious damage and short explosion time, it is easy to cause incomplete combustion, resulting in a large amount of carbon monoxide gas to poison personnel. Therefore, the consequences of dust explosion are also extremely serious.
Safety measures for the operation of air crushing equipment
In order to minimize dust hazards, in addition to the use of dust removal equipment and protection, the following management measures need to be implemented:
(1) Increase the humidity of the working area, strengthen ventilation, reserve fire extinguishing equipment, etc.
(2) Because the dust is slightly leaky in the manufacturing process, the dust will emerge, causing pollution in the operation area. Therefore, the tightness of the joint should be ensured.
(3) Configure protective equipment for the operator according to the regulations, and the operator should also develop the habit of wearing protective equipment correctly according to the regulations.
(4) Maintenance and management of the existing dustproof equipment! Ensure its normal operation and play a dust-proof role. At the same time, funds should be invested to carry out technical transformation to improve the dustproof efficiency of dustproof equipment and operation automation.
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