Talking about the cooling of the steel barrel coating drying line

In the production of steel drums, the drying oven is always accompanied. The surface treatment before the coating of steel drums must be carried out after moisture drying before painting; the curing of the paint film after coating needs drying; some of the front surface treatment process also has a treatment liquid heating process, and the painting process also has a paint heating process. . Therefore, the drying and heating process is very important in the production of barrels. However, most of the barreling companies in China only pay attention to production, and do not pay attention to the cooling of the drying line, which not only affects the health of the operating workers, but also is not conducive to production safety and quality assurance.

First, the harm of high temperature environment of drying furnace on human health

People must maintain a certain body temperature, because the body temperature will increase the speed of the body's chemical reactions, the body's metabolism will occur obstacles.

The substances in the human body are continuously oxidized, continuously generating heat, producing heat and cooling, and human body temperature can be kept within a certain range. The mechanism by which the body regulates body temperature can be divided into two types: chemical and physical. Chemical body temperature regulation is achieved through the physiological changes of the nerve-body fluid system. When the outside temperature is low, the heat production is enhanced, and when the outside temperature is high, the heat production is weakened. Physical body temperature regulation means that the body exchanges heat by convection, spokes, evaporation, and other physical means and environments. People in the high temperature environment, the regulation of body temperature * physical adjustment mechanism.

Through the skin surface convection, radiation and evaporation heat, the body is the main way to heat. In addition, some of the heat is also released through the lungs and respiratory tract, and generally does not exceed 3%.

The surface of the human body is constantly drained of water, and these waters take away heat when they evaporate. At room temperature, evaporative heat dissipation only accounts for about 1/4 of the total body mass. However, when the temperature is higher than the temperature of the human skin, and there is an external radiant heat source, the human body almost completely evaporates to radiate heat. The amount of evaporative heat dissipation is related to the temperature and relative humidity of the air and the speed of the air flow. In different climatic conditions, there is a different maximum possible evaporation. If the amount of sweat is greater than this limit, it is ineffective for evaporative heat dissipation. When you are engaged in physical labor in a high temperature environment, you often sweat too much and cannot evaporate completely.

The body must keep its heat balance. If the body generates heat and absorbs more heat than the heat, it is in a state of regenerative heat, which increases body temperature. When working at room temperature with different strength physical activity, the body temperature will have different degrees and increase; at high temperatures, due to the combined effects of temperature and labor intensity, the human body to adapt to this environment and labor intensity, certain physiological functions appear Certain degree and change should be regarded as normal. If the stored calorie exceeds a certain limit, it may lead to dysfunction of body temperature regulation and symptoms of overheating or heat stroke.

The illnesses that occur in the high-temperature environment of the drum drying line are mainly heat stroke and enthalpy.

The main manifestation of heat stroke is a significant increase in body temperature, sometimes up to 40 °C. During the onset of the disease, the patient first had some prodromal symptoms such as dizziness, headache, thirst, nausea, etc.; when the condition was severe, the body temperature increased significantly, the pulse was fast and weak, the flushing was flushed, the breathing was rapid, and the subjective symptoms were more pronounced; Coma appears. If it is not timely, it can be life-threatening due to heart and respiratory failure.

The enthusiasm is caused by excessive sweating and loss of excessive salinity in high temperature environments, resulting in hyponatremia and hypokalemia in the blood. The calf muscle spasm occurred in the light, and the muscle pain was severe in the extremities. Finally, muscle spasms appeared in the whole body. In general, patients who are eager to suffer from diarrhea can quickly disappear as long as they add salt water.

High temperatures can also cause indigestion, affect liver function, and cause respiratory infections and nervous system diseases.

Second, the basic measures for heat insulation and cooling of steel drum coating drying room

When the radiant heat and convective heat on the surface of the drying oven significantly affect workers, insulation measures should be taken as far as possible. After taking heat insulation measures, the external surface temperature should not exceed 60°C, preferably below 40°C.

The heat insulation method of the steel drum drying furnace mostly uses the thermal insulation type. Thermal insulation is to cover the surface of the furnace body with a layer of poor thermal conductivity material to reduce the heat released from the furnace body. The worse the thermal conductivity of the material, the greater the thickness, the more the heat dissipation of the furnace body decreases. Thermal insulation methods generally include wrapping, painting and filling. The package is wrapped in a heat-generating furnace using a plate, fiber, or other insulating material. Smearing is the application of water-soluble powdered insulation material into a paste that is applied directly to the surface of the furnace body. Filling is to fill insulation material into the additional shell of the furnace. Among them, the wrapping method is most widely used. When selecting thermal insulation materials, attention should be paid to the high temperature resistance of the materials. Some insulation materials have poor high temperature resistance, such as cork board, sugar cane board, wood fiber board, etc. They can only withstand 100~120°C and are not suitable for steel drum drying furnaces. Some insulation materials are highly resistant to high temperatures, and products such as asbestos, slag wool, and diatomaceous earth can withstand temperatures of 600-800°C. The use of thermal insulation materials should pay attention to moisture, because the insulation properties of the material after moisture absorption should be reduced, and some materials will be released due to excessive water absorption.

III. Measures for Natural Ventilation and Cooling of Steel Tank Painting and Drying Workshop

The air in the paint shop is resistant to the temperature increase due to the heating of the oven. If you can continue to use the air with lower temperature to replace the air with higher temperature in the workshop and discharge the hot air in the workshop, you can play the role of cooling. The removal of hot air and the introduction of cold air can be done mechanically or by natural forces. The former is called mechanical ventilation and the latter is called natural ventilation.

Natural ventilation is due to the effect of hot or wind pressure. Hot pressing is the gravitational effect of cold air and hot air. When the indoor air heats up, it becomes lighter than the air with lower outdoor temperature. As a result, the hot air in the room rises upwards, exits from the upper opening of the workshop, and the cool air from the outside increases. The orifices in the lower part of the workshop flow in, thus forming a natural pressure of hot pressing. The effect of wind pressure is that when the outside wind blows to the factory, positive pressure greater than atmospheric pressure will be generated on the windward side of the plant, and negative pressure less than atmospheric pressure will be generated on the leeward side of the plant, due to the two aspects of air With the pressure difference, the air outside the factory building enters the plant from the opening on the outer wall of the windward side, and the air inside the building is discharged from the opening on the back wall, so that the natural pressure of the wind pressure is formed. In fact, the hot pressure and the wind pressure act at the same time. However, because the outdoor wind speed and the wind direction often change, the wind pressure effect changes greatly, while the change of the hot pressure effect is smaller.

In order to achieve good results in nature, design calculations should be carried out in advance to determine the amount of ventilation required to remove waste heat from the workshop, and the area of ​​the air intake and exhaust openings of the workshop, as well as the types of intake and exhaust windows, should be determined based on the necessary ventilation. Whether to install windshields. However, natural conditions often have large fluctuations. Therefore, it is necessary to make necessary adjustments to natural ventilation as external weather conditions change. This benefit adjustment is to use the plant's skylights and side windows to open and close the air to properly organize the air flow so that the air with low outdoor temperature entering the workshop is blown to the work zone first, or the hot air in the workshop can be discharged smoothly. If the temperature in the workshop increases, the natural ventilation can be increased by increasing the area of ​​the intake and exhaust air windows.

Natural ventilation does not require external power, so it is more economical than mechanical ventilation, and the amount of ventilation generated by natural ventilation is large. Therefore, it is a commonly used ventilation method for steel drum painting and drying plants.

Fourth, steel drum coating drying line mechanical ventilation cooling measures

In steel drum painting and drying workshops, in order to increase the airflow speed at a local site, or to send cold air directly to the work site, local mechanical air supply methods are often used. Such measures can be divided into dry air, spray air and wet air. In general, for the paint film drying effect, it is required that the drying room should be as dry as possible. Therefore, in most areas of China, the cooling method of sending dry air is mostly used.

To send dry air, the untreated air is sent to the work site with a fan. Its purpose is to generate a large wind speed at the work site to promote the body's evaporation and heat dissipation. The human body mainly has three types of heat dissipation: convection, radiation, and evaporation. When the air temperature and the surface temperature of the equipment, walls, etc., around the human body are higher than the human skin temperature, only the sweat is evaporated by evaporating the sweat, and the speed of evaporation of the sweat is related to the speed of the wind, so sending the dry air to accelerate the air flow speed can strengthen the air speed. Heat dissipation. The fans that send the dry wind are generally placed near the work place and do not receive air ducts before and after. There is also a way to lower the temperature of the tunnel to the workshop to cool down.

5. Health care and organizational measures for cooling and cooling of steel barrel coating and drying lines

Health measures for cooling off the heat, including health checkups, refreshing drinks, and Jianli’s high-temperature operation lounge.

Workers who work at high temperatures should undergo health checks before and during the summer before they get into employment. Patients with heart, lung, vascular organic diseases, persistent hypertension, stomach and duodenal ulcers, active tuberculosis, liver disease, and kidneys Diseases, obesity, anemia, and physical weakness after acute infectious diseases and organic diseases of the central nervous system are not suitable for high-temperature operations.

The sweating of high temperature workers is quite a lot. In the hot season, a worker can sweat 8 to 10 liters in eight working days, sometimes reaching 12 liters, and lose about 40 grams of salt with sweat. Water, salt, a lot of loss, if not compensated in time, may lead to systemic fatigue, weakness, loss of appetite, indigestion, and even cause phlegm. Therefore, it is necessary to supply a cool salted drink to supplement the loss of water and salt, and to relieve heat and quench thirst.

High-temperature workshops should set up workshop lounges. The lounges should be located in the working area or not far from the working place, and should be insulated from the effects of high temperature and radiant heat. The interior should have good ventilation, and the temperature should generally be maintained at 30. °C below. Workers who work at high temperatures and rest for a short period of time can quickly dissipate the heat accumulated in the body and restore the physiological function of the cardiovascular system.

The measures to prevent heatstroke and cool down include the establishment of appropriate labor rest systems, the arrangement of high-temperature workers' lives, and publicity and education.

In order to avoid overheating of high-temperature workers, the duration of continuous work should be shortened, the number of alternating work and rest should be increased, or the time of work and rest should be appropriately adjusted, such as morning and evening work, and rest at noon. For workers who work at high temperatures, they should also be aware that the promised workers will be fully rested after work. For high-temperature workers and their families and related cadres, it is necessary to step up publicity and education on prevention of heatstroke and heat stroke.

In fact, the heat-proof cooling of the steel drum drying room is not only beneficial to operators, but also has a great bearing on product quality and production safety. Especially in summer, when the drying room temperature is high, it is not conducive to the drying of the paint film of the steel drum. When the indoor ventilation is unfavorable, the organic solvent is hardly volatilized and discharged in time. The vapor of the organic solvent accumulates in the room and not only affects the workers. He is in good health and is prone to accidents such as burning and explosion. Therefore, the cooling of the steel drum drying room is of great significance.