Ventilation of industrial premises: types, requirements, design and control

– довольно сложная задача. Designing ventilation of production facilities is a rather difficult task. Creation of schemes is carried out taking into account specificity of activity of the enterprise. Let us further consider what the ventilation of industrial premises is. также будут описаны в статье. Its types and requirements to it will also be described in the article.

Classification

The main task of the ventilation system of industrial premises is to promptly "catch" all impurities and remove them. These or other settings are selected depending on the specific operating conditions. Air in the units can be moved by a mechanical or natural way. There is also a classification according to the principle of work. Ventilation can be inflow, exhaust or mixed. Each group has its own subgroups of equipment. So, supply ventilation can be local. It is presented in the form of an air shower, veil or oasis. обеспечивает рассредоточенный или направленный приток. General ventilation for industrial premises provides a dispersed or directed inflow.

Natural filtering

функционирует из-за разницы давления и температуры на улице и в цеху. The supply and exhaust ventilation in the production room is functioning due to the difference in pressure and temperature in the street and in the workshop. The driving force in this case will be thermal or wind pressure. Due to the pressure drop, the expanded masses are forced out of the shop. In their place, in turn, tightened cold - clean. In the windward area a high pressure region is formed. It increases the flow of outside air. From the leeward side of the pressure is always reduced. This contributes to the outflow of waste mass. , функционирование которых основывается на физических законах, применяются, как правило, на предприятиях с интенсивным тепловыделением. Ventilation systems and equipment , the functioning of which is based on physical laws, are usually applied in enterprises with intensive heat release. However, not always a powerful exchange will ensure the formation of proper working conditions for employees. . The stronger the temperature drop at the ceiling and floor, the higher the shop itself, the more efficiently the natural ventilation of the production premises . If there are cracks in the windows and walls, doors or gates often open, drafts may appear. This helps to reduce the temperature in the shop. In summer, the ventilation rates are significantly impaired at the sites remote from windows and doors.

Aeration

. It uses a flexible duct . Aeration is carried out by the principle of natural draft. не осуществляется, установки не монтируются. In some cases, during the construction of a building, the ventilation system of the production room is not calculated , installations are not mounted. In such cases, it is possible to place canals and shafts in the shop operating from the heat head. прикрывается дефлектором. A flexible duct is covered with a deflector. The wind blows it, due to which the rarefaction region is formed. нашли широкое применение на сельскохозяйственных и животноводческих фермах, в небольших пекарнях, в кузнях. Such branches for ventilation have found wide application on agricultural and animal farms, in small bakeries, in smithies. They are installed on the highest part of the roof. Aeration is considered one of the most effective methods of natural ventilation. Often it is used in factories where a lot of heat, poisons and gases are generated.

Device

предполагает обустройство трех уровней проемов с форточками, имеющими специфическую конструкцию. The natural ventilation of industrial premises involves the arrangement of three levels of openings with a window, having a specific design. The first 2 rows are placed from the floor at a height of 1-4 m. In the roof, light-aeration lanterns equipped with adjustable window pans are mounted. In summer, pure flows pass through the lower transoms, and dirty flows go up. When calculating the system, the area of the openings and windows is determined. The worst conditions for the operation of the installation are windless weather. It is taken as a reference point. работает эффективно. With wind, such ventilation of production premises works efficiently. However, with a certain strength and direction of the wind, a reverse thrust may appear. As a result, air, mixed with gases and dust, is sent to the premises where people are. To prevent the spread of harmful substances installed lights with protection from the wind. In summer, the supply air is cooled by spraying cold water into them. It comes from the nozzles, which are located at the windows. With this cooling, the humidity rises slightly.

SNiP: ventilation and air conditioning

The Rules set out a number of prescriptions for buildings in which a natural filtration scheme is used. In particular, it is necessary that the perimeter of the structure is open for air access. The Rules also specify that shops with a height of no more than 1 floor or those located on the last floors of the building are aerated. In multi-span rooms, the installation of natural ventilation is significantly hampered. If the shop width is more than 100 m, there are practically no clean flows to its center. In such cases, special Baturin lanterns are mounted (not inflated). They provide separate channels for inflow and exhaust. However, in winter, such an installation may cause an undesirable drop in temperature in the shop. . To prevent such consequences, forced ( artificial) ventilation of production premises is mounted.

Advantages and disadvantages of aeration

The ventilation elements are controlled mechanically. One of the main advantages of the aeration scheme is the low cost of components. In this case, the installation can provide a sufficiently powerful air exchange. Meanwhile, she also has several shortcomings. First of all, the functioning of the system depends on the weather conditions. In addition, as mentioned above, it does not ensure the delivery of clean streams to remote sections of the workshop. Another disadvantage is the complexity of management. Do not use aeration in enterprises where technologies that imply the spread of harmful substances are used.

Forced ventilation of production premises

It allows you to bring the indicators of streams delivered to the shop to regulatory levels. The required parameters are defined in SNiP. принудительным способом имеют следующие достоинства: Ventilation and air conditioning by the forced method have the following advantages:

1. The operation of the units is not related to the outside temperature of the shop.
2. You can delete streams, as well as submit them from any site.
3. The calculation of the system is accurate.
4. You can change the multiplicity in any range. It is calculated based on the diameter and speed of the grinding / sharpening wheel.

Most popular installations

At present, exhaust ventilation is widespread. The installation limits the spread of contaminated streams and removes them directly from the source. The quality of the ventilation depends on the correct selection of equipment, the degree of atmospheric discharges, and the shape of the receivers. The key elements of the plants are:

1. Suction.
2. Fan.
3. Retraction.
4. Filters.
5. Exhaust channel.

The entire volume of dirty streams should catch the receiver and transmit it further through other elements.

Specificity of suction

Air receivers are closed and open type. The latter include:

1. Protective cover.
2. Exhaust hood.

The protective casing eliminates the flow of dust, which is formed, for example, in the carpentry shop for polishing, polishing, etc. It is equipped with a visor and is installed across the movement of the particles. The exhaust hood reduces the area of hot air that contains harmful impurities and rises according to the convection principle and removes it. It must be sized to completely cover the source. The umbrella can be equipped with overhangs. They are made of thick fabric or hard sheets. It is more convenient to use open umbrellas. In them overhangs do not interfere with the access of employees of the enterprise. In harmful production, the flow rate entering the umbrella is from 0.5 m / s, if it is without impurities, then 0.15-0.25 m / s.

Onboard / articulated telescopic suction

They are installed directly on the workplace on galvanic or pickling baths. The air moves over them and draws harmful acid and alkali vapor before they spread throughout the shop. With a small (up to 70 cm) bath width, single-sided suction is installed, if this parameter is greater than the specified value, double-wing elements are mounted. In addition, the latter are equipped with structures that ensure the evaporation of fumes from the surface of the liquid. The volume of flow passed through these installations will depend on the level of steam virulence, temperature. Of no less importance is the size of the surface of the liquid. As the vapor quickly destroys the metal, the suction is made of PVC and other resistant materials. Hinge-telescopic receivers are quite common. такого типа оснащаются выдвижными элементами. Ventilation pipes for this type of extractor are equipped with retractable elements. They can be brought directly to the source of pollution. In shops with soldering irons and welded devices, suction pumps are installed directly into tools.

Receivers of closed type

They include:

1. Cabins.
2. Exhaust hoods.
3. Cameras.
4. Boxes-shelters.

The latter are used in enterprises with particularly poisonous and radioactive substances, where workers perform all manipulations in gloves or with the use of mechanical devices. Cabinets are installed in workshops with intensive release of harmful gases. с полной изоляцией источника загрязнения считаются самыми эффективными. Ventilation pipes for extraction with complete isolation of the source of pollution are considered to be the most effective.

Electrical installations

Ventilation systems of industrial premises of forced type are equipped with special units. They are electric fans. As a rule, axial or radial models are installed. The latter are also called "snails" because of the shape of the hull. It incorporates a wheel with blades. During the movement, the streams enter the hull, change direction and are fed into the tap under pressure. Absorbed masses are often saturated with aggressive and dangerous compounds, and sometimes with explosive substances. Depending on the impurities, ventilators are installed at the enterprises:

1. Standard. They are designed to catch streams with a low content of dust, the temperature of which is up to 80 degrees.
2. Anticorrosive type. Such installations are used for trapping the vapors of acids and alkalis.
3. Have protection from sparks. They are used for explosive mixtures.
4. Dusty. These installations are designed to filter streams containing particles in an amount greater than 100 mg / m ³ .

Axial fans include inclined blades mounted in a cylindrical body. During operation, the flows move parallel to the axis. These units are installed, as a rule, in mines, emergency channels, etc. The advantage of such devices is that they can supply air in opposite directions.

Dust Collectors

. The current norms and standards determine the ventilation requirements for the production premises . The plants must function in such a way that the content of harmful impurities is within the permissible value. Accordingly, cleaning efficiency is one of the key parameters. In some cases, one dust collector is sufficient to filter the air. In this situation, cleaning is called single-stage cleaning. If air pollution is significant, multi-stage filtration is organized. The type of treatment plant will depend on the form, chemical composition and volume of impurities. The simplest design of a dust collector is a dust chamber. It significantly reduces the intensity of flow, due to which harmful impurities settle. However, this setting can only be used for primary filtering. Dusty chambers can be labyrinth, simple, with a bump.

Cyclones

They are inertial dust collectors and are used to filter air with a particle content of more than 10 microns. The cyclone is made as a cylindrical metal container, tapering downwards. The air is fed from above. Under the influence of a centrifugal force, dust particles hit the walls and fall. Purified air comes out through the pipe. To increase the volume of retained dust, water is sprayed inside the housing. These facilities are called cyclone-rinsers. Recently, the most popular are the rotoclones and rotary dust collectors.

Filters

They are also used to purify the air. Filters can work on electricity. In this case, particles charged positively are attracted to negative electrodes. A high voltage passes through the filter. For subsequent cleaning of the electrodes from dust, periodic automatic shaking occurs. Caught dust is sent to the drives. Coke and gravel filters are also used in practice. The devices for thin and medium cleaning are made of special material. It can be synthetics, felt, porous fabrics, nets. They catch not only dust, but small particles of oil. However, such materials are rapidly clogged, require regular cleaning or replacement. If necessary, ejection systems are used to filter the air from explosive compounds or gases, as well as corrosive substances. They have 4 cameras: a diffuser, a neck, a confuser and for discharging. Streams enter into them under high pressure. The direction is set by the compressor or fan. Dynamic pressure in the diffuser is converted to static pressure. After that, the flow is directed outwards.

Alternative option

Before directing air into the room, it must be treated: warm or cool, filter. In some cases, it is also required to moisten it. For these purposes, ventilation is used. It consists of:

1. The fence.
2. Taps.
3. Filters.
4. Heaters.
5. Fans.
6. Distributors.

Installation of installations is carried out according to certain rules. A supply chamber is provided for the fan, filter and heater . Receivers should be located at a height of 2 meters from the ground, in places far from sources of pollution. In some cases, installation above the roof of the structure is allowed. When choosing the installation site, the direction of the wind should be taken into account. On the outside, the air intakes are covered with umbrellas, blinds or grilles. Filters in installations can be of various types. As a rule, nonwovens are used. In winter, air heating is carried out with the help of calorifiers or toners. The heat carrier is either electricity or water. For irrigation, special irrigation chambers are installed. In them, a fine-dispersed air fraction is sprayed. Cooling is carried out in a similar way.

Local settings

They include air souls. They are pure flows directed to work sites. The purpose of such a shower is to enhance the heat transfer of the employee's body to prevent overheating. The settings can be mobile or stationary. Souls are equipped with hot shops, as well as rooms with infrared radiation greater than 350 W / m2. Norms depend on temperature, severity of work, and intensity of radiation. The average t in the shower is +18 ... + 24 deg. The flow moves at a speed of 0.5-3.5 m / sec. Its exponent is directly proportional to the radiation intensity and air temperature.

Oases and veils

These devices are often used in large enterprises. Oases serve the site of the workshop, fenced off from the rest of the area with the help of light screens. Within its limits, air moves at a certain rate and has a predetermined temperature. Curtains are used to prevent workers from overcooling and cooling the shop through openings or open doors. They can be without heating or with it.

Preventive supervision

выполняется при: Such sanitary control of ventilation systems of industrial premises is carried out at:

1. Reconstruction, planning, construction or change of technology / profile of the enterprise, site, shop.
2. Start-up of installed or repaired treatment plants.
3. The introduction of new technological aggregates, processes or chemicals that can have a harmful effect on the environment or human.

The reconstructed or newly constructed ventilation systems are launched by the commission in accordance with the established procedure. It includes a representative of the Sanitary and Epidemiological Service. Evaluation and inspection of the ventilation system can be carried out after the completion of all construction and installation activities. In this case, before the inspection it is necessary to establish all technological processes according to the regulations. In the course of the survey, production plants must function with the planned load, the ventilation devices must reach the set productivity. The preventive supervision is carried out in the form of:

1. Execution of conclusions on design materials on the correctness of the selection of the ventilation scheme. The documents for reconciliation are working and technical drawings.
2. Observation of the installation of ventilation systems.
3. Participation in the admission and processing of the conclusions on the compliance of the units with the current sanitary and hygienic prescriptions.

Ongoing examination

It is carried out in the form of sampling:

1. Conditions of the environment in the areas of location of sampling devices. Inspection can be carried out and directly on the workplace.
2. Work, condition, operation of ventilation systems.

The periodicity and volume of the sampling survey is established by the sanitary doctor. At the same time, the degree of possible negative impact of the working environment on a particular enterprise on personnel is taken into account.