Talking about the dustproof process of steel barrel production edging process

Talking about the dustproof process of steel barrel production edging process

Yang Wenliang Xin Qiaojuan

In China's steel drum production enterprises, most of the current edging processes on the production line. The barrel grinding process is a kind of barrel welding edge treatment process. The barrel welding edge treatment is to pre-treat the seam of the barrel body seam before seam welding, the main purpose of which is to eliminate the oxide on the edge. Oil stains, etc., to facilitate seam welding; secondly, to reduce the thickness of the edge, in order to ensure the quality of the subsequent process. At present, the main process in China is to sharpen the edges, that is, to grind the weld edges with 4 to 8 sets of grinders. The barrel industry is called the edging process.

People who see the edging production with their own eyes will be shocked because the working environment here is too bad, there are deafening noises, there are diffuse flying dust, smoke and smog... The noise comes from the friction between the grinding wheel and the steel plate; Dust is the grinding wheel and the particles under the grinding of the steel plate; part of the smoke is the product of the high temperature of the binder in the grinding wheel, and part of the result is the vaporization of the oil on the surface of the steel drum at high temperature. In such a work environment, the environmental protection department often asks for rectification as soon as possible, but it has not changed much so far. Why is this happening? Because the process is very good, and does not require much investment.

So, how can we reduce the smoke of the edging process? Let us first see how the smoke is formed.

First, the generation and harm of smoke and dust

During the edging process, the air in the workshop is filled with a large amount of smoke. Smoke and dust are tiny particulate matter. Dust is a granular waste formed by the friction between the grinding wheel and the steel plate. The smoke is formed by the condensation of the oil on the steel plate and the organic matter in the grinding wheel by the frictional heat. Especially when processing the galvanized sheet, the zinc is thermally oxidized to become the zinc oxide. Harmful. After the particulate matter enters the air, the diameter of which is larger than 10 microns will settle down quickly due to gravity. Only in the air near the grinding wheel will there be a relatively stable high concentration of coarser particles, and the fine particles will be longer. Floating in the air, these particulate matter can cause the grinding wheel motor and transmission system to malfunction, causing disease in the human body. People working in a dusty environment can also affect work efficiency.

After the human body inhales particulate matter, the diseases that may be caused are pneumoconiosis, alveolitis, bronchitis, occupational asthma, metal smoke, poisoning, cancer, and the like. In addition, particulate matter can affect human lung function, and some particulate matter can also cause dermatitis and conjunctivitis.

Second, the basic dust prevention measures in the workshop

In the workshop, even if measures to control the smoke are taken, some smoke and dust will inevitably scatter. Some of the smoke that diffuses with the airflow in the working environment is deposited on the top beam, the wall surface, the surface of the equipment, and the like. After being piled up to some extent, it may fall again due to mechanical vibrations, etc., suspended in the air and spread to the breathing area of ​​workers. These floating soots are sometimes much higher than the soot concentration produced by daily operations.

In order to avoid the above situation, in the workshop with smoke, it is better to install the flowering board so that the top beam is not exposed, and there is no pipe under the ceiling, no wiring; the wall surface, the window frame, etc. should also adopt a structure that is not easy to accumulate soot. The joint between the floor and the wall should preferably have a suitable arc for cleaning.

If a lot of soot is accumulated on the floor of the workplace in a short period of time, the ground may adopt a lattice structure, and the lower portion is vacuumed by a local air suction device.

Equipment layout in the workplace is also related to smoke control. If the equipment is properly arranged and the channel size is appropriate, it is convenient to fully implement the smoke control measures. At the time of design, it is important to simplify the process system and enhance continuity to minimize dusting opportunities.

Dust-cleaning equipment and non-dusting equipment should be located in different workshops or completely isolated by partition walls to limit the spread of soot and minimize the impact on other working environments.

As far as the characteristics of the edging process are concerned, among the technologies that can achieve the same process effect, the technology that emits the least amount of smoke should be used; the economy cannot be ignored, but the direct economy should not be considered, but it should be caused by the smoke. The hazards are taken into account in the comprehensive economics to choose production technology. The following dust-proof measures can be taken in terms of production technology:

1. Choose the right raw materials

In the past, many manufacturers did not consider the harmfulness of the grinding wheel material, so that harmful substances were used. In the future, other raw materials should be used instead. The choice of this choice is that the substitute should be much less harmful than the original substance; the substitute cannot make the product quality or process effect significantly lower than the original; the production cost of using the substitute is not higher or higher than the original Not much; the supply of substitutes should be stable.

The use of silicon carbide, corundum, etc. instead of sandstone with high free silica content as a grinding wheel is a representative example of the use of substitutes.

2, sealed

If the dusting process is completely sealed, it is possible to prevent the smoke from spreading to the working environment, but it is practical to be completely sealed due to the operation. Therefore, it is generally necessary to perform partial suction on the closed cover to make the clean air outside the cover flow into the cover to prevent the dusty airflow from escaping.

In addition to sealing or semi-sealing the dusting equipment, it is also possible to confine the surrounding environment of the worker in an environment where smoke is emitted. For example, in a large number of workshops where smoke is emitted, it is difficult to take thorough measures to prevent pollution, and the worker's operation room can be sealed to send fresh air to the room.

3, automation

The use of automation or remote operation has a significant effect on the prevention of smoke and dust hazards, because the workers do not need to directly participate in the operation of emitting smoke, and can fully achieve complete sealing and dust collection. However, when you need to enter the inside of the equipment for maintenance, you may encounter high concentrations of dust, then use personal protective equipment.

Third, the common ventilation method to remove dust

Ventilation is available in both full ventilation and partial inhalation. The use of comprehensive ventilation to control dust is mainly to clean the air and gently and continuously dilute the harmful substances in the entire air of the production site so as not to exceed the allowable concentration, so it is also called dilution ventilation. General ventilation generally requires a much larger amount of air than local inhalation, so it is not as economical as a partial inhalation. Steel drum edging workshops use full ventilation to control soot. Because the grinding wheel set generally has eight, and is relatively scattered, it is difficult to set up a local suction device in terms of process and operation.

Local inhalation is the removal of harmful substances from the source of the source before it is released into the air of the worker's breathing zone. The local suction device is composed of a suction hood, a pipe, an air purifier and a fan. When used for vacuuming, the air purifier is the dust collector.

For houses that use dust suction devices to remove dust, the outdoor air should be sent to the workshop under controlled conditions to replace the exhausted air. Especially in the case of relatively large inspiratory volume, this problem should be paid more attention to. It will cause problems such as the effect of vacuuming, the difficulty of maintaining a comfortable temperature for workers, or the blowing of cold winds to workers. The amount of replenishment air is at least equal to the total amount of air discharged from the workshop by the suction ventilation system, preferably a little more to minimize air leakage around the building.

It must be heated when replenishing air in winter and cool down in summer. Therefore, when designing a local inhalation system, care should be taken to minimize the amount of inhalation or recycle air while ensuring the inhalation effect, but this should not be caused by circulating air. It is a prerequisite for jeopardizing the health of employees.

The soot-containing air sucked away by the local suction system needs to be dedusted and purified before being discharged into the atmosphere. Commonly used dust collectors are mechanical dust collectors, scrubbers, fabric filters and electrostatic precipitators, each of which has many different types. It can be selected according to the situation.

Fourth, the main management of dust prevention

In order to prevent the occurrence of hazards from soot, in addition to technical measures, management should be strengthened. The main contents include: keeping the operating environment clean, keeping the dustproof equipment intact, checking the dustproof effect frequently and conducting dust prevention education and training.

Practice has proved that in the production environment where smoke is generated, even if dust-proof measures are taken, it is inevitable that some smoke will fly away. For a long time, smoke will adhere to the windows, walls, mechanical equipment surfaces and lighting fixtures. These deposited soot should be cleaned regularly. Cleaning dust can be done with tools and equipment such as wet mops, vacuum cleaners, and blow-off sweepers.

As with production equipment, dust-proof equipment must be carefully maintained and intensively repaired to ensure that it can always perform well. A checklist should be prepared to list the premises that must be inspected, and check for incidents at regular intervals. In case of abnormality, the cause should be investigated, necessary repairs, replacements and supplements should be made and recorded.

The effect of dust prevention should be monitored by technical measurements. The content of the measurement is mainly the soot concentration of the working environment and the technical performance of various dustproof devices. This measurement should be carried out frequently and problems should be resolved in a timely manner.

To do dust prevention work, employees should also be educated and trained in dust prevention. The contents should generally include: the hazards of smoke and dust, relevant regulations, dust prevention methods, use and maintenance of dustproof equipment, and management of the working environment. In addition, special training and training on dust control technology and smoke detection methods should be carried out for technicians engaged in dust prevention work.

In recent years, a variety of new welding edge treatment processes have emerged at home and abroad, which proves that people still recognize the impact of the edging environment. These new processes include milling, cleaning, and fully automated high-frequency welding. The milling process eliminates noise and dust, and is a transitional process that is more suitable for general small barrel mills. It is simple and feasible. Although the cleaning process also eliminates noise and dust, it is accompanied by hydrochloric acid and the like to corrode oxides and grease on the weld edges, often accompanied by toxic and harmful gases, and there is also cleaning waste liquid, which is still unfavorable to environmental protection. Therefore, it cannot be promoted. Only the automatic high-frequency welding process is characterized by the advanced nature of the welding machine. The welding edge can be welded without strict treatment, and the processing process is removed, thereby reducing the labor intensity, reducing the production cost, and improving the environmental pollution. This is the replacement process for steel barrel welding.