Installation of ventilation in industrial premises. What types of ventilation are used in modern industries How to install an exhaust hood in production

Creating a truly comfortable and cozy atmosphere in the workplace not only increases the productivity and efficiency of the labor process, but is also a prerequisite that the sanitary authorities put forward. Therefore, ventilation systems are just as important in production as are the elements of the central heating system or the services of the electrical network. The installation of such systems is a rather complicated and time-consuming work, so they usually do not do it yourself, but trust professionals with solid experience. In any case, knowing about the principles of operation, design and development does not hurt anyone.

Air conditioning of premises of various sizes in production is carried out using the most complex systems, which, in addition to the air duct, also include various heaters, filters, coolers, recuperators, fans and other elements. The ventilation system, regardless of the type of production process, area and size of workshops and air pollution, must perform the following functions:

• Providing fresh purified air to the employees of the enterprise.
• Removal of unpleasant and extraneous odors, as well as dust from the room.
• An important function of the ventilation system is filtration from various harmful impurities that arise as a result of certain technological influences and conditions.

Sidebar: Important: In industrial and production workshops, mechanical and natural ventilation is used for normal air exchange. When designing, it is necessary to take into account various regulatory documents regulating the state of factory and factory shops.

During the production process associated with the manufacture of pharmaceuticals or products from refined oil, toxic elements are released that pose a certain danger to human health, so the ventilation system must ensure their effective and immediate neutralization.

Only highly qualified specialists, certified engineers and professionals should be allowed to work in the development or in the production room. At the same time, it is necessary to take into account climatic and weather conditions, the number of workers, the size of the premises, production features and many other nuances and features.

1. The elements of any ventilation system are air ducts, exhaust and supply devices, as well as equipment that helps create a comfortable and cozy microclimate inside the room (this includes humidity stabilizers, as well as heaters and air conditioners).
2. For normal ventilation of various objects in production conditions, it is necessary to use such equipment that is able to remove particles of dust, aerosol and gas from the air, which appear as a result of the operation of complex equipment.
3. In some industries (such as pharmaceuticals or the production of high-precision electronics) the creation of specific working conditions is required, therefore, all kinds of additional elements are added to the powerful ventilation system, such as special filters and high-power air conditioners.
4. According to the operating instructions for certain types of equipment, those workshops and areas where fumes that are hazardous to human health may be present should be additionally equipped with extractor traps that are separated from the general workshop network.
5. Devices that carry out hygienic and sanitary control of ventilation systems are part of air exchange systems, and depending on their indications, special equipment can be connected that removes various toxic impurities and purifies the air.
6. During the design of ventilation systems, it is necessary to take into account such a parameter as the cost of operation. It is best if the hot air that leaves the room is used in special exchangers, and the cold air is used to cool machines and other equipment.

Table: heat consumption of the ventilation system

Ventilation, which is used in industry, is divided into the following types:

1. General exchange ventilation is responsible for the normal replacement of air masses in the room. The most typical example is an ordinary axial fan, which is inserted into a wall or window duct. Based on such parameters as the length of the duct and the cross section, the appropriate power of the equipment is selected.
2. (or individual type) - allows you to purify the air from various toxic impurities, smoke, heavy dust and other substances that can harm human health, directly in the workplace.
3. Emergency air purification from gas, smoke or all kinds of toxic impurities is resorted to exclusively in force majeure cases, therefore the standards here differ from those generally accepted in production and will not be considered in this context.

Ventilation is also mechanical and natural. The natural scheme carries out the removal and inflow of air masses through draft, which occurs due to the difference in temperature and pressure inside and outside the production room. The effective functioning of such a ventilation system is affected by:

• Difference in ambient temperature inside the production hall and outside.
• The difference in atmospheric pressure near the outlet of the hood and near the floor in the room.
• The speed of movement of air masses on the street.

Varieties of the ventilation system

The natural ventilation and ventilation system is silent, environmentally friendly and economical. However, changing weather conditions can have a very negative impact on its effectiveness. Mechanical ventilation is free of such a disadvantage, which is able to move the air flow through an air duct of any configuration and section to any distance. In such cases, it is often carried out the installation of additional equipment that heats the air, and also humidifies, dries or filters it if necessary. To date, the most popular combined ventilation systems, which use elements of both mechanical and natural systems.

To implement normal natural ventilation, there is no need to spend significant funds, conduct electricity or buy additional equipment. Turning to professionals who will make accurate calculations and plans for optimal ventilation in a particular production or industrial premises, you can solve the problem of ventilation and compensate for such a disadvantage as dependence on changes in wind speed and direction, pressure and temperature.

The implementation of mechanical ventilation of industrial and industrial premises requires a fair amount of electrical energy, so this method is not always cost-effective. The advantage of this ventilation method is the independence of air flow and temperature from environmental conditions. The air in such systems is often heated and also cleaned or, if necessary, cooled. To date, the most popular is the combined ventilation system, which combines elements of mechanical and natural ways of ventilating the room.

The ventilation standards include certain provisions, according to which the ventilation system must be located in absolutely all production workshops and premises. Moreover, regardless of the functional features of the occupied area and the number of employees on it. The capacity of the ventilation equipment should be enough to clean the air in the room as quickly as possible in case of emission of harmful substances or smoke. The development of a project, according to which the work of the ventilation system will be implemented in the future, should be carried out by professionals who are able to do this in full compliance with applicable laws, documents and regulations. During design, the following parameters must be taken into account:

• inside a workshop or production facility.
• fire safety conditions.
• Air humidity indicators.
• The presence and number of toxic and poisonous substances that pollute the environment.
• Climatic features.
• Space and functionality.

It is worth noting that providing each employee with air is a norm, the implementation of which is monitored by various authorities and services. The norm is thirty cubic meters per hour on an area less than or equal to forty square meters. For large industrial complexes, such standards are calculated separately. When calculating the technical characteristics of the ventilation system, it is worth considering the following nuances:

• The ventilation system should not be a source of noise, which is strongly emitted even during the operation of technological equipment and machines. The noise level should be at a medium or low level, otherwise a long stay in the workshop will become problematic.
• In the event that the ventilation system has been installed for a long time, and has not been thoroughly cleaned for a long period of time, then it is most likely that it itself is the cause of increased pollution of the surrounding air space. To ensure that the ventilation system does not act as a source of pollution, it is recommended to clean it at least several times a year.

The tasks of the ventilation system of the supply type include compliance with sanitary and hygienic standards due to the assimilation of excess moisture, dilution of toxic emissions that can damage the human body and reduce the concentration of harmful impurities. All this allows the employee to be on his own site in comfortable conditions that comply with all established norms and rules. In the event that the room temperature is low, then the supply-type ventilation system can solve this problem by heating the supply air masses.

The simplest device that is installed in various workshops and industrial premises is a fan that has an air vent. Due to the fact that the amount of various harmful and toxic impurities in enterprises, as a rule, is higher than the norm, the use of only one ventilation system is not always effective. To maximize the safety of employees, modern factories use both natural and mechanical systems.

On the modern market, there are a huge number of various systems, ventilation, which allow you to create the most safe and comfortable working conditions within the workplace. The widest selection of devices that differ from each other both in functionality and in price will satisfy the needs of even the most demanding customer. During the design of a complex industrial ventilation system, it is necessary to install both supply equipment, which is the guarantor of the supply of clean air to the space of workshops and plant premises, and special exhaust units. With their help, you can remove from the workplace air saturated with pathogenic bacteria, toxic substances, dust, smoke and other harmful elements. It is selected based on the characteristics of production.

They choose one or another variation of equipment on an individual basis, with the obligatory consideration of the differences and features that are inherent in a particular industrial or construction large facility.

The ventilation system must have the following parameters:

• Profitability.
• Efficiency.
• Reliability.
• Payback speed.

Thanks to clean and cool air, it is possible to achieve not only a good mood, health and performance of employees, but also low wear of technological equipment and various tools. It is economically feasible when drawing up a project to add a device that is connected to the ventilation system and provides a comfortable indoor climate.

To date, the best way to control the parameters of the ventilation system is to use automatic computerized systems that make changes to certain characteristics based on data received from external sensors. Thus it turns out to achieve maximum economy and efficiency in work.

Thanks to the use of supply or exhaust circuits, you can easily bring the humidity indicators at the enterprise to normal, as well as neutralize, heat, cool, filter or humidify the air. A huge advantage of forced ventilation is that its operation is not affected by external conditions and weather factors. Air removal and supply can be made from the required point. You can make accurate calculations of supply or exhaust ventilation and draw up a schedule of costs.

The operation of ventilation systems is affected not only by the competent selection of equipment and installation, but also by the rarefaction of the atmosphere, the shape of the air inlets, the correct installation of filters, fans, air ducts and other elements. In enterprises, it is most advisable to install axial or radial blowers powered by electricity. Thanks to such a solution, it is easy to provide employees with a clean airspace in the workplace, devoid of harmful impurities and toxic elements. For better filtration today, electrostatic precipitators and other components are often used, which can maximally secure even an environment saturated with aggressive chemical compounds and components.

Air conditioning in enterprises and industries allows you to achieve a normal microclimate, which is especially important for the optical industry, instrument making, electrovacuum industry and other areas where maintaining a certain humidity in the room is a very important point. To set up and install the ventilation system, it is best to contact professionals with experience and knowledge in their field.

Ready-made ventilation systems need periodic cleaning, because if the channels are clogged, it becomes unsafe to be in the production workshop or room due to the high concentration of dust particles and harmful elements. For maximum efficiency, today they use various filters made of felt, fabric, porcelain rings and all kinds of porous materials that perfectly absorb dust and toxic substances that can damage human health.

Features of equipment installation

During the installation of ventilation systems in factories and industrial facilities, it is necessary to take into account a huge number of features and nuances that directly affect the durability of the structure and the efficiency directly during operation. That is why for the installation of individual elements of the air exchange network it is necessary to involve highly qualified specialists who have the appropriate knowledge and experience. It is also important to choose the right place for the installation of equipment, such as filtration systems, fan units, heat exchangers and other units.

In industrial and industrial premises, they are usually attached directly to the ceiling. If desired, they can be hidden using hanging decorative panels. In those premises that are used for commercial purposes, it makes sense to use channels made of plastic or copper, which are reliable and durable and have an attractive appearance.

Currently, the following types of air channels are used in construction:

• Rigid. For their production, materials such as fiberglass, multilayer aluminum, galvanization and others are used. Of these elements, the installation of virtually the entire ventilation system is carried out. The only exceptions are special parts of a shaped sample, which are used for branching, contours and turns. To transport air that contains various harmful impurities, it is worth using air ducts with walls of increased thickness.
• Flexible. Their main purpose is the communication of various sections and openings with the main air ducts. For the design of the local ventilation system, the purpose of which is to purify the air in the immediate vicinity of the workplace, aluminum sleeves are often used.

The installation of ventilation ducts in industrial and industrial premises is carried out in the following order:

1. To begin with, the parameters of the wall thickness and the cross section of the air channels are calculated, after which, based on the data obtained, the mass of each element of the ventilation system is calculated. Sometimes the installation of square ducts is not possible due to insufficient space. Therefore, faced with a similar situation, it is worth using rectangular ducts to solve the problem.
2. Then, at the joints, you need to designate the fixation points for the air ducts. Thanks to this, you can easily calculate the required number of fasteners, brackets and other fittings. It is worth remembering that for mounting brackets it is undesirable to allow oscillations of long sections of the network to occur directly during the passage of air through them. It is best to provide the structure with an excess number of fasteners, since in this case they will withstand even increased loads without problems.
3. When the installation of the main channels has been completed, it is possible to proceed with the installation of separate suction and spray devices. For such cases, it is recommended to use special hoses with flexibility and the desired cross section.

findings

Installation and design of industrial ventilation systems is a responsible and complex process. The finished project must comply with strict building codes and current regulations. The health of employees and the performance of the entire team directly depend on this.

An industrial hood is designed to create air circulation inside production facilities in order to remove harmful substances and gases. Refers to industrial equipment installations. This is especially true in ventilation systems at heavy and chemical industrial enterprises.

The main unpleasant factors that the hood can remove are harmful substances, production waste, unpleasant odors, tobacco smoke and street smog. The main elements of the hood:

1. Air ducts.
2. Electric motors.
3. A collection of fans in ducts.
4. Purification filters.

Ventilation of industrial premises is divided into:

• Suspended. All elements of such a system, as a rule, are located under the ceiling of the room, without cluttering up the working area of ​​the production process. But this requires high-altitude installation of the components of such a system, and thus, the involvement of more qualified personnel for work, with a permit to work at height.
• Embedded. In some cases, exhaust elements can be installed in the design of the installation and workshop facilities. This will save part of the space in the room, but will require the development of additional technical documentation (plan, design features) of such an installation.
• Wall. This is perhaps the most common installation scheme for ventilation of industrial premises, because. does not require special approach to installation. This arrangement of the hood elements reduces the complexity of maintaining the ventilation system.
• Island. This type of installation involves the installation of hood components, and most importantly, an air intake in a certain place in the production room. As a rule, such a place is the source of the maximum emission of harmful substances and gases in large workshops.
• Corner. Basically, equipment and machines are mounted in the central part of the room, for maximum access to them in the process of work. Thus, the corners of the workshop remain unused. Therefore, such places become attractive for installation where additional equipment is needed, in the form of local exhaust ventilation.

According to the principle of operation, exhaust ventilation systems of production are of various types: in-line (natural) and forced. The first production exhaust ventilation system is used if the level of contamination of the premises is not so high. At its core, the flow hood uses the movement of air mass from the workshop to the outside, due to the difference in temperature and pressure in the room and outside it. This eliminates the use of electric motors and fans from the circuit, which makes it possible not to use electricity during its operation. But if the emissions of harmful substances in industrial premises are massive, then a forced local exhaust ventilation system is indispensable.

Its design includes electric motors connected to fans, which allow "sucking" significant volumes of air from the room, which in turn leads to a significant cleansing of the "atmosphere" of the workshop from pollution. Often, filters are installed in the forced exhaust system to help solve the problem of environmental pollution. Ventilation air exchange in production includes two pipelines: suction and exhaust. Between them there is a fan unit with an electric motor that creates forced air circulation. The presence of an additional element of the gas analyzer can significantly save energy. Its purpose is to control the content of harmful substances in the workshop. Depending on their concentration, the analyzer controls the engine speed. That is, with a large gas content, it increases the speed, and, consequently, the volume of air space pumped out of the room. With a low content of harmful substances in the "atmosphere" of the workshop, he switches the engine to low speed, or turns it off altogether.

As a rule, along with the extract from the room, the supply of fresh air from the street is also used. Such a system is called a circulation system. It, in turn, allows you to better clean the room and “saturate” it with fresh air.

There are two types of exhaust fans: radial and centrifugal. The speed of air movement in radial fans is higher than in centrifugal ones. This is due to the fact that the air mass in them moves in a straight line. In turn, such a scheme provides a faster movement of air flows, and, consequently, a more “high-speed” air exchange.

Hood - snail

Perhaps the most common scheme for an exhaust ventilation unit for industrial workshops is a snail hood. In its design, it differs significantly from centrifugal fans.

This model is characterized by ease of manufacture and installation in the workshop. Its main element is the frame on which the electric motor is installed. A round fan box is mounted to the engine mounting flanges. A centrifugal fan in a sound-insulated housing, connected to the motor shaft, is placed through the central hole in the duct inside. Due to the special angle of installation of the blades on the wheel of the fan air duct, when it rotates, a vacuum is created in the cavity behind it. This ensures a constant flow of air to the exhaust unit and its movement further in the outlet pipeline.

The number of blades, their dimensions and sealing at the points of contact between low and high pressure determine the flow rate. The wheel diameter can vary from 25 to 150 cm, depending on the volume of air being pumped.

Snail hoods are divided into three classes:

1. Low pressure (P-100 kg/m²). They are used, as a rule, in domestic conditions and small workshops.
2. Medium pressure (P-from 100 to 300 kg/m²). The devices are used in the premises of production workshops of low gas content.
3. High pressure (P- more than 300 kg/m²). They are used in especially polluted places, whether it be paint shops, or areas of metallurgical plants with a high concentration of harmful substances.

Depending on the medium with which the blades will have to come into contact, they are made heat- and corrosion-resistant.

Calculation of supply and exhaust ventilation

Before starting the calculation of the main parameters of the hood, it is necessary to determine the source of harmful, combustible or explosive substances. But the calculation is based, as a rule, on the required amount of fresh air for one person. In this case, the calculation of the general exchange air concentration is determined as follows:

Air quantity: L=N × m, where N is the number of people working in the room, and m is the specific air consumption per person per hour.

According to the SNiP standards, the value of m is: 30m³/h for ventilated rooms and 60m³/h for unventilated ones.

If, however, not only harmful, but also dangerous substances are emitted into the "atmosphere" of the workshop, then the calculation is carried out according to MPC (maximum permissible concentration). The MPC norm for a particular substance is taken from special reference books and is strictly regulated by high requirements. In this case, the volume must be calculated:

The amount of air in case of hazardous emissions: L \u003d Mv / (mentioned - yn), where Mv is the mass of the substance released into the air (mg / h); mention - the specific concentration of this substance in the workshop space (mg / m³); yn is the concentration of the same substance in the air entering the room.

If there are several sources of harmful emissions in the workshop, then the calculation is carried out individually for each. And the overall result is the maximum value of the required volume of air entering the workshop. Because calculations are made on the influx of fresh air, then it must be clearly understood that exactly the same volume should be pumped out of the room.

Industrial hood filtration

Before the air enters the room, it is cleaned with filters. Also important is the cleaning of the air mass leaving the workshop. There are three types of filters:

1. Porous. The basis of the cleaning element was a porous material, like a cork.
2. Absorbent. In such a filter there is a material actively absorbing harmful emissions from the environment.
3. Fabric. Perhaps the most common filters. The fabric well retains various impurities from the air during the filtration process.

If the source of emission before drawing is massive, then the so-called multi-stage filtration is used. It uses several types of filters to better clean the environment from impurities.

There are also bulk filters. But in industrial hoods they are used extremely rarely due to the low efficiency in cleaning the air mass from pollution.

Promising directions of industrial hoods

One of the promising directions in the creation of hoods is the use of recuperators in the ventilation scheme. The basic principle of this device is to carry out heat exchange between the air flow entering the room and leaving it. Thanks to the use of recuperators in the ventilation system, it is possible to save up to 50% of the heat accumulated in the workshop. In them, the intersection of both flows occurs. In a simple version, the pipeline from the beginning of the discharge to the exhaust is blown by the air entering the workshop.

Another direction for improving industrial hoods was the replacement of galvanized air ducts with plastic ones. This significantly reduces the cost of the design of piping for industrial premises.

The use of asynchronous electric motors in the fan drive significantly reduced the noise from the operating equipment, and also increased its efficiency.

Conclusion

According to some estimates, industrial enterprises around the world emit up to 170 million tons of various substances into the Earth's atmosphere. And a considerable number of them get there due to emissions before the exhaust from the shops of factories and combines. Therefore, along with the creation of conditions for the work of employees at the enterprise, the hood is also required to filter the outgoing air. This aspect is strictly regulated at the level of environmental organizations in many countries of the world.

The fundamental difference between industrial ventilation is that the equipment copes with the maintenance of large premises, often with very difficult microclimate conditions. Harmful substances, hot steam or dust can be released into the air. The main task of the exhaust ventilation of industrial premises is to quickly “catch” all unwanted impurities and remove them without harming the environment.

Types of room ventilation

According to the method of air movement, there are two types of ventilation:

• mechanical;
• natural.

According to the principle of operation, all ventilation units are divided into:

• Supply(for supplying fresh air), can be local (oasis, curtain or air shower), as well as general (directed or dispersed inflow).
• exhaust(evacuate exhaust air), are general or local.

Natural ventilation in industrial buildings

Any natural supply or exhaust ventilation of a production facility operates using the difference in temperature and air pressure in the workshop and on the street. This means that the driving force of natural traction is wind and thermal pressure.

Due to the temperature difference, expanded warm air masses are forced out of the workshop, and clean, cold air masses are drawn in their place. From the windward area, an area of ​​​​high pressure is formed, which increases the flow of fresh air from outside. On the leeward side of the building, on the contrary, the pressure is always lowered, which contributes to the outflow of exhaust air. Physical laws are successfully used for ventilation of enterprises with intense heat release. But not in all cases, a powerful air exchange guarantees the creation of all the necessary conditions for the work of personnel.

The more noticeable the temperature difference near the floor and the ceiling of the workshop, as well as the higher the room, the more efficient the system will work.

If there are gaps in the walls and windows of the workshop, doors or gates are often opened, drafts are likely to occur and the temperature drops. In the summer, in areas remote from doors and windows, the norms of ventilation of industrial premises are violated.

Air aeration in the room

Aeration in some cases creates an effective air exchange based on natural draft. For its implementation, aeration lamps are installed - specially designed ventilation elements.

Sometimes, during the construction of a production facility, ventilation is not calculated, the equipment is not installed. Then it is possible to place shafts and channels operating due to thermal pressure in an already finished workshop. The exits of the mines are covered with deflector heads. The wind blows over the deflector and forms a rarefaction area in the pipe, increasing the suction of air. A similar system is widely used in agricultural and livestock buildings, forges, small bakeries. The pipe is installed on the highest ledge of the roof.

Aeration is one of the most efficient examples of natural industrial ventilation. It is used in industries with abundant formation of gases, poisons and heat.

Natural ventilation device in production

In serviced buildings, 3 levels of openings with specially designed vents are equipped. The first two rows of openings are located at a height of 1-4 meters from the floor. Light-aeration lamps with adjustable vents are installed in the roof.

In summer, streams of clean air enter through the lower transoms, while dirty ones go up. In the cold season, air penetrates through the middle row of vents and, warming up, reaches the level of the staff.

The intensity of ventilation is regulated by different positions of the vents. Calculating the ventilation of the production room, determine the area of ​​the vents, openings. Since the worst time for the system to work is warm, calm weather, it is taken as a reference point.

In windy weather, natural traction works better. But with a combination of a certain force and wind direction, reverse thrust can be created.

Mixed with dust and gases, clean air is directed to the areas where people are located. To prevent the spread of dust and dirt, lanterns of an inflatable design with wind protection are installed.

In the hot season, the supply air is cooled by spraying cold water into it from nozzles located in the area of ​​the vents. The air cools and the humidity increases slightly.

There are some requirements for buildings with natural aeration:

• its perimeter must be open to air access;
• one-story workshops or those located on the last floors of high-rise buildings are aerated.

It is very difficult to mount natural ventilation in multi-span industrial premises. With a workshop width of more than 100 meters, delivering clean air to the center of the building is almost impossible. Then, for aeration, Baturin's non-blown lanterns are installed with a separate channel for exhaust and inflow. In winter, such a system can cause an undesirable drop in temperature in the working area of ​​the production room. Therefore, in multi-bay workshops, forced ventilation with inflow heating is usually installed.

All elements of aeration are controlled mechanically.

The advantage of this type of ventilation of industrial premises is the possibility of providing powerful air exchange.

Another plus is the low cost of mechanisms.

Disadvantages:

• dependence on the weather;
• complexity of management;
• the impossibility of providing remote workplaces with fresh air.

Aeration, as a type of ventilation of industrial premises, is unacceptable if the technology involves the spread of harmful impurities and dust. Because filtration of exhaust air masses is impossible.

Forced ventilation in industrial premises

The supply or exhaust ventilation schemes of industrial premises on a mechanical draft make it possible to bring the parameters of the air supplied to the premises to the required ones (moisten, filter, cool, heat and neutralize the air).

Benefits of forced ventilation:

• its work is not related to the temperature outside;
• it is possible to supply, remove air from the required point;
• it is possible to change the ventilation rate of the production premises within any limits;
• it is possible to make an accurate calculation of the exhaust or supply ventilation of the production room.

Among the types of ventilation used today in industrial premises, forced exhaust ventilation is the most widespread.

Ventilation of industrial premises limits the spread of dirty air and removes it directly from the source of its occurrence.

The quality of the local ventilation of the industrial premises is affected by the correct selection of equipment, the shape of the air inlets, and the degree of rarefaction of the atmosphere.

All types of exhaust units for ventilation of industrial premises consist of such components as:

• suction (air inlet);
• fan;
• air ducts;
• filters;
• exhaust channel.

The entire volume of dirty air must be captured by the air inlet and then transferred through the local ventilation system of the production facility.

Types of industrial air inlets

Suction or air intakes for ventilation systems are of two types:

• closed;
• open.

Ventilation air inlets of open type consist of:

• protective cover;
• exhaust umbrella;
• on-board or articulated-telescopic suctions (installed directly at the workplace);
• movable air inlets.

Such receivers are distinguished by the fact that the opening for the intake of dirty air is located a little further from the place of its release.

The protective anti-dust casing eliminates the column of dust (the so-called dust torch), which is formed, for example, in carpentry: when grinding, polishing, on grinding machines. The device contains a visor and is installed across the movement of dust particles.

The multiplicity of local ventilation of the production room is calculated based on the speed and diameter of the grinding or grinding wheel.

Exhaust hoods reduce the distribution area and remove hot air containing hazardous impurities and rising upwards according to the principle of convection. The size of the umbrella should completely cover the area of ​​the hot air source. Umbrellas are made with or without overhangs. Overhangs are made of rigid sheets or dense canvas. Open umbrellas are more convenient, as overhangs do not interfere with personnel access.

In hazardous industries, the speed of the air flow entering the umbrella should be from 0.5 meters per second and higher. If the umbrella removes hot air without impurities, the speed should be between 0.15 and 0.25 meters per second.

Air inlets in the form of slots or side suctions are installed on pickling and galvanizing baths. The air moves over the bath and draws out the harmful fumes of alkalis and acids before they spread throughout the room.

If the width of the bathroom is small (up to 70 cm), single-sided suctions are installed.

Wide bathtubs are equipped with double-sided suctions, as well as structures that blow off evaporation from the surface of the liquid, “with an overflow”.

The volume of air passed through such devices depends on the surface area of ​​the liquid, the degree of toxicity of the vapor, and the temperature of the liquid. Since vapors quickly destroy metal structures, the ventilation of industrial premises in this direction is made of sustainable materials, such as PVC.

In welding and soldering shops, suctions are installed on vertical or beveled panels with many holes.

Telescopic and articulated suctions are very common. Thanks to the retractable pipe, the suction end can be brought closer to the desired location.

In workshops with semi-automatic welders and carbon dioxide soldering irons, suctions are mounted directly into the tools. Such equipment is effective at air exchange up to 20 cubic meters per hour.

If the place of work of the welder is not fixed, mobile suctions are used, some of them are attached to the welding machine on suction cups.

Closed type suctions:

• fume hoods;
• cabins;
• shelter boxes;
• cameras.

Fume hoods are installed in workshops with abundant release of toxic fumes and gases.

Shelter boxes do not provide for open openings and are used in industries with radioactive and highly toxic substances. The worker performs all manipulations with rubber gloves and built-in sleeves or mechanical devices.

Local exhaust ventilation in industrial premises with complete isolation of sources of hazardous emissions is called aspiration and is considered one of the safest and most effective schemes.

Types of industrial fans

Air in forced ventilation systems is driven by mechanical devices: blowers powered by electricity. Most often, radial or axial models are installed.

A radial or centrifugal fan is also called a "snail" in the form of a housing into which a wheel with blades is built. During the rotation of the wheel, air enters the housing, changes direction and is supplied under pressure to the air duct.

Exhaust air is often saturated with harmful and aggressive components and even explosives. Depending on possible impurities, fans are used:

• standard type for air temperature up to +80 degrees with a small amount of dust;
• anti-corrosion type - for alkali and acid vapors;
• with protection against sparks - for explosive air mixtures;
• dust - are used if the dust in the air is more than 100 milligrams per cubic meter.

Fan numbers indicate the diameter of the wheel, expressed in decimeters.

Axial fans are inclined blades installed in a cylindrical housing. During operation, the air moves parallel to the axis of the fan. Such models are installed more often in medium-sized networks, emergency exhaust ducts and in mines. Their advantage is that one fan can supply air in two opposite directions, carrying out both exhaust and inflow.

Air is supplied to the required points through air ducts. Most often they are made of sheet metal, and when working with aggressive substances - from plastic, ceramics and other stable materials.

Dust collectors and filters for industrial work

The quality of air emissions into the atmosphere is regulated by the requirements for ventilation of industrial premises. Therefore, dirty air from industrial plants must be filtered before being released into the environment. One of the most important parameters calculated for the ventilation of a production facility is the efficiency of air purification.

It is calculated like this:

where Kvh is the concentration of impurities in the air before the filter, Kout is the concentration after the filter.

Sometimes a single dust collector or filter sufficiently cleans the air, then cleaning is called single-stage. If the air is very polluted, it is necessary to organize multi-stage cleaning.

The type of cleaning system depends on the amount of impurities, chemical composition and form.

The simplest design of dust collectors is dust settling chambers. In them, the speed of the air flow is sharply reduced and due to this, mechanical impurities settle. This type of cleaning is only suitable for primary cleaning and is not very effective.

Dust chambers are:

• simple;
• labyrinth;
• with a baffle.

To catch dust with particles larger than 10 microns, cyclones are used - inertial dust traps.

Cyclone- This is a cylindrical container made of metal, tapering from below. Air is supplied from above, dust particles under the influence of centrifugal forces hit the walls and fall down. Clean air is removed through a special pipe.

Two small cyclones installed one behind the other increase the cleaning efficiency by 90% compared to one large one.

To further increase the amount of trapped dust, water is sprayed into the cyclone body. Such devices are called cyclones-washers. The dust is washed off with water and sent to the septic tanks.

The modern type of dust collectors is rotary or rotoclones. Their work is based on a combination of Coriolis forces and centrifugal force. The design of rotoclons resembles a centrifugal fan.

Electrostatic precipitators- This is another way to clean the air of dust. Positively charged dust particles are attracted to negatively charged electrodes. A high voltage is passed through the filter. To clean the electrodes from dust, they are automatically shaken from time to time. Dust gets into the bins.

Water-wetted gravel and coke filters are also used.

Medium and fine filters are made of filter material: felt, synthetic non-woven materials, fine meshes, porous fabrics. They catch the smallest particles of oils, dust, but quickly clog and require replacement or cleaning.

If the air needs to be cleaned of very aggressive, explosive substances or gases, ejection systems are used.

The ejector consists of four chambers: rarefaction, confuser, neck, diffuser. The air enters them under high pressure, entrained by a powerful fan or compressor. In the diffuser, the dynamic pressure is converted into static pressure, after which the air mass is carried out.

Supply ventilation in production

The norms of ventilation of industrial premises are specified in SNiP 41-01-2003. Before entering the room, the air should be treated: cooled or warmed, filtered from dust, and sometimes its humidity should be increased.

Supply ventilation device:

• air intake;
• air ducts;
• filters;
• heaters;
• fan;
• air distributors.

When installing the ventilation of the production room, a supply chamber is organized to accommodate the heater, filter and fan.

Air inlets are located at a height of 2 m above ground level, in places remote from pollution sources, sometimes above the roof of the building. When choosing a place, the direction of the winds is taken into account. Outside, the air intakes are covered with blinds, grilles or umbrellas.

The supply air is cleaned by filters of various types, most often made of non-woven materials.

The air in winter is heated by shadows or heaters. The heat carrier is water or electricity. If humidification is required, irrigation chambers are installed, where a finely dispersed fraction of air is sprayed. The air is cooled in the same way.

Local supply system in the room

The requirements for ventilation of industrial premises are not always met by general ventilation. And then a local supply system is installed.

Types of local supply ventilation:

• air-thermal curtains;
• air showers;
• oases;
• air curtains.

air shower it is a stream of clean air directed to the workplace. Its purpose is to increase the heat transfer of the employee's body and prevent overheating.

Shower installations can be:

• stationary;
• mobile.

Showering is organized in hot shops, as well as when infrared exposure of personnel is more than 350 W/sq. meter.

The norms of ventilation of industrial premises of this type depend on the severity of the work, the air temperature in the workshop and the intensity of IR radiation. On average, the air temperature in the air shower is from +18 to +24 degrees. The flow moves at a speed of 0.5 to 3.5 meters per second. The speed is directly proportional to the air temperature and the radiation intensity. And the temperature of the inlet flow is inversely proportional to these indicators.

To change the direction of the air flow, special rotating pipes are attached to the ends of the air ducts.

Air oases serve the whole section of the workshop, which is fenced off from the rest of the area with light screens. In the area, the air moves at the calculated speed and temperature. In the oasis, the ventilation rate of the industrial premises is carefully calculated.

Air-thermal and air curtains are designed to prevent hypothermia of employees and to cool rooms through open doors or openings.

There are 2 types of curtains:

• with supply air heating;
• without heating.

General ventilation is necessary in cases where moisture, heat and pollution enter the entire volume of the workshop and it is impossible to comply with the norms of ventilation of industrial premises with the help of local measures. With a general exchange ventilation system, the exhaust air in the production room is diluted with clean air to the requirements of sanitary and hygienic control. This is not an economical and not very efficient system.

Industrial production is characterized by specific working conditions, among which there may be toxic, gas, thermal emissions from process equipment into the environment. In order to eliminate such negative factors, industrial ventilation is organized inside the industrial workshop - a complex, multi-level system for normalizing microclimatic indicators. Designed to remove harmful heat and gas emissions from industrial equipment from the working area of ​​personnel.

Types of industrial ventilation

The classification of industrial ventilation is carried out according to the criteria of localization, direction and mode of operation. Let's consider in more detail.

According to the principle of operation

• Natural. It is based on the natural circulation of air flows with different temperatures, pressures, and densities. A heavy cold air stream displaces a lighter and warmer one. In an industrial premises, this process can occur through natural gaps, leaks in window doorways, or organized supply and exhaust openings, closed with gratings, deflectors.
  Depends on atmospheric conditions, strength and direction of the wind, season (in winter, ventilation is better due to strong draft). This method is not suitable for all industries, especially where there are harmful emissions from operating equipment. It can be installed, for example, in agricultural premises.

• Artificial ventilation. If production involves a side effect in the form of toxic heat and gas emissions, mechanical ventilation of production facilities is strictly required. The main function is to divert the exhaust air flow from the working area of ​​the personnel, prevent the penetration of harmful vapors into other rooms, compartments, as well as supply fresh outdoor air (purified or unpurified) by the general flow or by address.
  It is organized with the help of mechanical means of supply and removal of air masses (supply, exhaust fans, roof units). It is a more efficient way of cleaning, circulating the air flow inside the industrial workshop.

According to the principle of localization

• General exchange. It is designed for uniform cleaning of the entire workshop from harmful technological heat emissions, normalizing the temperature and humidity index, air speed. Quickly copes with a small percentage of air pollution.
• local ventilation. It is used when there is a localization of a large amount of toxins, vapors, smoke, etc. in a certain place. It is installed directly above the source of increased heat and gas emission. Hoods or a flexible duct connected directly to the equipment may be used. It is used in conjunction with the general ventilation system as an additional air-purifying equipment.
• Emergency. It is installed and used in the future in case of emergency, for example, fire, excessive release of toxic substances from industrial equipment, high levels of smoke, etc.

According to the principle of flow direction

• Supply ventilation installations. The principle of operation is based on the displacement of warm exhaust air by a cold influx through organized exhaust openings at the top of the workshop. They can be both natural organization and mechanical.
• Exhaust ventilation units remove the exhaust air flow together with burning particles, smoke, toxic fumes, excess heat, etc. Structurally, they can be general or local, most often with forced induction, since it is quite problematic to remove polluted air naturally.
• The air handling unit is used most often, it provides the necessary circulation of air masses inside the industrial workshop. Most often with mechanical equipment (supply, exhaust fans).

Equipment for ventilation of industrial premises

The forced ventilation system consists of the following elements:

• air ducts;
• fan;
• air filters;
• air valves;
• air intake grilles;
• noise-absorbing insulation;
• air heater (air heating);
• automatic control unit if necessary.

The mechanical exhaust ventilation device is organized according to the same model, with the exception of the air heater, filters, which are not needed for the exhaust air.

Local exhaust ventilation of industrial premises is organized by exhaust hoods, flexible air ducts connected to a common air exchange system.

In addition, supply and exhaust ventilation can be equipped with a heat recuperator to save energy during the heating of the incoming flow. The supply masses are heated by the heat of the exhaust air, without mixing with it.

Industrial ventilation requirements

Ventilation and air conditioning of industrial premises is regulated by the general requirements of SanPiN, as well as by the parameters specific to the given workshop of the enterprise. These include:

• mechanical ventilation of industrial premises must comply with fire safety rules;
• removal of substances hazardous to health, emissions without access to the work area of ​​personnel;
• obligatory hygienic and fire safety certificate of the materials from which the elements of the ventilation system are made;
• anti-corrosion coating of air ducts, or they must be made of materials resistant to such influences;
• the thickness of the coating of ventilation ducts with combustible paint should not exceed 0.2 mm;
• for personnel working areas located directly inside the workshop, the concentration of harmful substances should not exceed 30%;
• humidity, speed indicators of air flow are not standardized in the summer;
• in winter, the temperature indicator of the air inside the workshop with the personnel located there is at least 10⁰ C, in the absence of people - at least 5⁰ C;
• in summer, the temperature indicators of the internal and external air flows are equal, or the internal temperature does not exceed the external temperature by more than 4⁰ С;
• the requirements for industrial ventilation that are not used in the summer of the workshop are not regulated by the temperature indicator;
• the total noise level inside the industrial hall should not exceed 110 dBa, this includes the operating noise of the ventilation system.

The above list is quite general. In practice, the requirements for ventilation of industrial premises are supplemented by individual parameters of production, the design of the workshop, the specifics of products, etc. In addition, it is imperative to take into account how heating and ventilation interact inside the workshop. And it should also be taken into account that lighting and ventilation of industrial premises are also interconnected.

Ventilation device. Stages of work

According to SNiP, industrial ventilation and air conditioning must be installed in all rooms of the workshop, without exception.

Ventilation and air conditioning of industrial premises perform the following tasks:

• removal of air masses filled with excessive heat, toxic fumes, gas formations, burning particles, smoke, etc.;
• additional cleaning by the filtration system of the air flow coming from the process equipment and containing hazardous impurities;
• supply of personnel with a constant supply of fresh air, normalization of the temperature and humidity balance, which determines the sanitary and hygienic control.

Installation of a ventilation system for industrial premises takes place in several stages:

• preparatory - the initial stage at which the design is carried out, the corresponding calculations. Based on this, the optimal equipment is selected, components, main elements, assemblies are transported;
• assembly - there is a compilation of individual elements, air ducts into a single complex. The ventilation system is mounted, the electrical component is assembled, connected to the mains;
• commissioning - a test check of the correct functioning, quality, efficiency, signing the commissioning certificate.

Design of ventilation of industrial premises

The design of industrial premises ventilation is a complex, multi-component process that is best entrusted to professional design engineers with many years of experience in this field. The list of actions carried out in the design of the ventilation system of industrial premises:

• preparation of technical specifications for design, which includes the necessary requirements for the organization of air exchange, parameters of technological equipment;
• approval of the terms of reference;
• an aerodynamic calculation of general ventilation, local air exhausts in industrial premises is carried out, the purpose of which is to determine the optimal internal section of the air ducts;
• selection of ventilation equipment according to the calculated characteristics, parameters;
• selection of additional elements necessary for adjustment, balancing of the ventilation system;
• drawing up drawings of the future ventilation system using specialized programs;
• drawing up schemes for the distribution of key components of the system in accordance with the norms and requirements.

Ventilation of industrial buildings. Documentation

The required documentation for the design and installation of a ventilation system includes:

• basic information about the specifics of production, the design of premises, buildings;
• general scheme of the optimal location of ventilation equipment;
• specification of the ventilation system;
• a list of materials from which it is necessary to make elements of the future installation;
• documents on thermal, fire insulation of ventilation ducts;
• drawings of the ventilation network, including the building diagram, floor level marks, dimensions and diameter of ventilation ducts, intersection of air ducts with other structural elements and sections of their insulation;
• separate drawings of important nodal connections, joints;
• schemes of non-standard fasteners, if they will be used;
• schemes of atypical structures, elements, nodes.

To carry out the installation of the ventilation system, a technological map is required, which determines the list of parameters that must be performed:

• features of the installation work associated with the specifics of production;
• requirements for the transportation of materials, products, the quality of work performed, insurance work, etc.;
• schemes of production quality control of the work carried out;
• determination of the degree of quality of equipment, materials, work technology;
• a list of necessary transport, material, technological resources;
• installation work schedule;
• technical, economic costs.

Calculation of the ventilation system of the production room

Calculation of the ventilation of the industrial premises should be carried out only by highly qualified specialists. The process is quite complex, taking into account many nuances that need to be linked into an overall effective ventilation scheme so that it shows the necessary results.

At the same time, it must be remembered that the calculation always takes into account the types of ventilation of industrial premises that it is decided to install. As an example, we briefly present two calculation formulas.

The first of them is used for workshops in which there are no emissions harmful to human health:

L = I * n

L- the required flow of air masses for a particular workshop, room;

I- air consumption for one person, determined by sanitary and hygienic, building codes;

n- the number of personnel.

For premises where emissions of hazardous substances by process equipment are expected, another calculation formula is used:

L = Lm.v. +(mc.c. -Lm.v. (Su.v. - Sp.v.)) / (C1 - Sp.v.)

Lm.v.- air flow removed by local exhausts;

mc.c.– hazardous substances (mg/h) coming from outside;

Su.v.– amount of hazardous substances (mg/m³) in the exhaust air;

Sp.v.- the amount of toxic substances in the supply air;

C1– amount of hazardous substances (mg/m³) allowed by the regulations.

If several types of hazardous substances are released, for each of them calculations are made according to this formula, the results are summarized.

Industrial ventilation installation

Industrial exhaust, supply ventilation systems are launched into the installation process only after the project has been approved, all preliminary work has been carried out and agreed. The place of installation, the location of the main elements is determined at the design stage.

First, the main structural elements are mounted. After that, the air duct system is divorced from them. During installation, many features are taken into account, for example, the spatial orientation of ventilation ducts, the material of their manufacture, the design of the ceiling, building elements, the presence of beams, etc.

All this directly matters for how the ventilation units, duct pipes will be attached. In industrial workshops, ventilation ducts are mounted to the ceiling. For commercial premises, it is preferable to use plastic channels due to their more attractive design. Most often, rigid or flexible air ducts are used, which have their own advantages and features.

Installation is carried out in strict accordance with the project, calculations, while observing the necessary requirements for ventilation of industrial premises.

Production control of ventilation

To monitor the quality of the microclimatic environment directly inside the working area of ​​the personnel, production control of ventilation is carried out. It is necessary to distinguish between checking the efficiency of the functioning of the ventilation system, air ducts and production control of ventilation systems.

In the first case, it is meant to check the air flow inside the ventilation ducts, distribution grilles, the compliance of these indicators with the design calculations is checked.

In the second, the production control of ventilation means taking the parameters of the air environment in the working area of ​​the personnel, determining the level of humidity and temperature for compliance with sanitary standards. Also, the control of ventilation systems of industrial premises is designed to monitor the level of hazardous, toxic substances in the air flow, whether the designed air exchange rate is observed.

This procedure is quite expensive and is carried out by accredited laboratories. As a rule, production facilities with the release of hazardous substances into the air in the course of their activities are inspected, as well as healthcare institutions, other socio-cultural, socially important facilities that are subject to periodic inspections by the state.

Performs the following tasks:

• control of ventilation systems of industrial premises is designed to ensure safe working conditions, primarily for personnel;
• provides safe conditions for the production itself;
• monitor temperature and humidity indicators, air exchange rate parameters, the concentration of harmful vapors in the working area for subsequent adjustment of the ventilation system (if necessary);
• minimize the occurrence of dangerous, emergency situations at work.

There is no doubt about how important industrial ventilation is, since it is a mandatory factor in the safety and health of workers in the workplace. Quite often, at industrial enterprises, people work with compounds, metals, impurities that are harmful to health, and the ventilation system of such premises should be at a high level.

Types of ventilation systems in production

Of course, in industrial premises, ventilation is not only subject to high requirements. Given the large area and often difficult working conditions, the ventilation of industrial premises is carried out in slightly different ways than for a residential building, for example.

The following types of industrial ventilation can be distinguished:

1. Natural.
2. Mechanical.

Depending on which circulation method is chosen for a given room, ventilation is divided into local and general exchange.

And already the systems for air ventilation in industrial premises are divided into:

• exhaust units - which forcibly carry out the outflow of large volumes of air from the workshop or any other room.
• supply units - they, in turn, provide an uninterrupted supply of fresh air to the ventilated room.

Industrial premises with natural ventilation

Natural ventilation is based on air exchange based on temperature differences. This indicator affects, first of all, the different specific gravity of air, inside the production hall and outside. The efficiency of such a system depends on the difference between these parameters. That is, the greater the difference in specific gravity and temperature, the greater the efficiency of this system.

This ventilation system can be organized and unorganized. In the first variant, the flow of air volumes is carried out through non-densities between windows or doors, as well as when opening vents or doors. The influx of fresh air is improved by the installation of special ventilation shafts, and the shafts or channels themselves are additionally supplied with special nozzles, they are also called deflectors.

This system, even of an organized type, can only be used in industrial buildings with a small area. Most often it is used in agricultural workshops or farms.

In workshops of a small area, natural ventilation is carried out by aeration. The calculation of the ventilation system for industrial premises using this method consists in the location of windows at a certain height, as well as special openings, the size of which depends on the size of the room itself.

For example, a small workshop in which ventilation will be carried out by aeration should be equipped with openings with special transoms. The openings themselves must be mounted in two levels. In this case, the height of the first level should vary from 1 to 1.5 meters from the floor, and the second level from 4 to 6 meters from the same floor.

Ceilings in the workshop should be equipped with transoms in the upper part, with the so-called aeration lamps with transoms opening to the required value.

This method is not applicable to production areas that contain harmful substances or exhaust gases that pollute the atmosphere. Natural circulation does not provide for air purification, therefore, for such premises, more complex ventilation systems should be installed with mandatory filters for air purification, both in the room and at the exit from it.

Industrial premises with mechanical ventilation

Industrial ventilation, carried out by this method, has a higher productivity compared to the natural method. In addition, special equipment is used here, which cleans the air coming from outside from dust and dirt, and the exhaust air released into the atmosphere also passes through a special cleaning system without fail.

These systems are mounted in such a way that they do not purify the air, but prevent the release of harmful dust or vapors directly into the working room itself.

The elements of installations with mechanical ventilation include air intakes. fans, ventilation ducts, filters for air purification from harmful impurities and, of course, a device for the outflow of exhaust air.

The calculation of the systems is carried out in such a way that the air from the outside is supplied to the place of the highest concentration of harmful substances. Most often, supply channels are made of ordinary steel. But if there are aggressive reagents in the work shop, for example, alkali vapors, then the installation of supply ventilation ducts should be carried out only from stainless steel, ceramics or plastic.

During the cold period of the year, large air volumes entering the workshops are usually heated using heaters for this. At the same time, so that in production it does not happen that the air becomes too dry due to heating, it is passed through special irrigation chambers. Passing through these devices, it is moistened by water or steam.

Recycling of industrial premises

Ventilation of industrial premises in this way is carried out by air circulation. When using this method, energy is saved, which goes to heat the air in the cold season. In this case, a continuous circulation of air is carried out. The purified outdoor air entering the room exits through a special installation, is cleaned and re-enters the working room.

But the use of such a system also has its limitations. For example, it is forbidden to use the recirculation method in those workshops where the air may have unpleasant odors or a variety of microscopic fungi. If the work shop contains substances belonging to the 1st, 2nd or 3rd hazard class, the recycling method is also prohibited.

Air conditioning of industrial premises

In this case, powerful systems are installed in production, which are configured specifically to create a favorable microclimate. In the settings, the corresponding parameters of air temperature, humidity and circulation inside the room are set. In difficult working conditions with materials of increased contamination or danger, additional requirements are put forward for installations, since they must provide additional air ionization and purification from bacteria.

In production, air conditioning is used mainly either to maintain the required humidity (when, for example, work is carried out on precision equipment), or to ensure certain sanitary conditions. As a rule, such opportunities are available only to air conditioning systems.

Ventilation systems of industrial premises based on air conditioning are divided into general and local. In systems of a general type, the installation is installed in a room specially allocated for it, and the inflow and outflow of air flows is carried out through air ducts. In the local type, the air conditioning unit is installed directly in the workshop, and ventilation is carried out without air ducts.

This method is today the most expensive, both in installation and maintenance. But this is the best option when creating a climate in industrial premises that is required by hygienic standards.

It is worth noting that practice has shown that these installations fully pay off over time, since precisely the microclimate is created in production, which contributes to an increase in the efficiency of personnel. Improving working conditions affects not only well-being, but also productivity, which quite naturally becomes higher.

As statistics show today, in industries where premises have a high level of heat and gas emissions, more and more enterprises began to install these particular installations. Only powerful equipment is able to provide those conditions of comfortable work in a difficult working environment.

Currently, there are special requirements for the ventilation of industrial premises: this includes ventilation equipment, ventilation ducts and shafts, and the efficiency of systems.