About that production ventilation is how important, it is not necessary to doubt as it is obligatory factor of safety and health of workers on production. Rather often at the industrial enterprises the people work with unhealthy structures, metals, impurity and the system of aeration of such rooms has to be at the high level
Industrial ventilation
Industrial ventilation represents complex of special devices and technology devices which provide organized air exchange of large volumes between the working room and the street. The quality of industrial vent systems is estimated by their opportunity to effectively delete the polluted air, to give instead of it fresh, to support according to regulatory requirements temperature condition and microclimate, at respect for standards of ecological and sanitary safety.
Requirements to the systems of industrial ventilation
Industrial ventilation is intended to provide processing of large amount of air, at the same time it works under big pressure and with high speed. When calculating ventilation and air conditioning systems of industrial facilities it is necessary to take the following requirements into account:
- Norms of health and hygienic control which define minimum time for localization and removal of harmful allocations in the working room, creation of comfortable situation for personnel or animals.
- The noisiness of operation of the equipment should not exceed the existing requirements.
- Fire-prevention. Components of industrial ventilation for rooms are selected and established strictly taking into account requirements of fire safety.
- Mounting modes of all devices and pipelines has to consider need of systematic surveys and technical maintenance.
- Energy saving. Ventilation has to be most effective at the minimum expenses of the electric power.
- The environment has to be protected from emissions from system.
The main requirements to ventilation and conditioning of industrial facilities are carried out even during design and direct construction of facilities. Design codes of heating, ventilation and air conditioning are stated in Building regulations Construction Norms and Regulations 2.04.05-91 "Heating, ventilation and conditioning".
Types of industrial ventilation
Industrial ventilation is the main means of improvement of air environment. It is accepted to allocate the following types of industrial ventilation:
- aeration or airing of rooms;
- all-exchange, artificial (mechanical) ventilation and air conditioning systems (pritochka and extract);
- local ventilating suctions;
- hot-air curtains and streams;
- ejection or compression and depression of air for its transfer on air ducts.
Besides, if to take way of movement of air as basis of classification, then ventilation can be:
- natural;
- artificial (mechanical);
Natural ventilation
The basic principle of work of natural ventilation is concluded in the movement of air masses under the influence of natural factors without use of special devices and mechanisms.
There are two types of similar air exchange:
- Airing
- Aeration
During airing the exchange of air masses happens because of the difference of temperature or density of air indoors and outside of or as a result of wind pressure.
Aeration is type of organized all-exchange ventilation which will be organized in cold shops and is carried out under the influence of wind pressure. In hot shops the aeration happens due to joint or separate action of thermal and wind pressures.
It is accepted to distinguish profitability and simplicity in operation from advantages of natural ventilation. However, essential shortcoming is the fact that the similar type of air exchange cannot be used in industrial rooms in which there is big release of hazardous substances. Besides, air which comes to shops is not processed, not purified, not moistened and not warmed up.
Mechanical ventilation
The principle of work of mechanical ventilation consists in compulsory air exchange where the movement of masses is carried out by means of fans. Fans can be centrifugal, axial or disk.
Depending on assignment (air moving direction) the artificial (mechanical) ventilation is divided into the following types:
- the incoming
- exhaust
- forced-air and exhaust
The plenum ventilation is necessary for giving to the shop of fresh air instead of remote. Exhaust throws out the polluted air masses out of limits of industrial premises. The supply and exhaust ventilation, as a rule, is applied in all industrial premises where the increased and especially reliable air exchange is necessary.
Local ventilation
Local ventilation is intended for removal of the polluted and heated air directly from places of its allocation. Thus, it interferes with its distribution on all area of industrial premises. It allows to reduce the number of necessary air exchange at all-exchange ventilation.
Local ventilation includes:
Hot-air curtains. These are special devices which give air with rather high speed on entrance cloth perimeter (doors, collar). In the presence in the building of apertures which remain open for a long time and for prevention of hit to the room of cold air the top arch of pass is equipped to air veils. It can be with heating or without it.
Hot-air curtains are established over passes which open more often than 5 times in working interval or more than for 40 minutes in one change. Besides, the similar ventilation system is mounted over doors of rooms which have no platforms and locks at temperature of external air below 15 °C.
At installation of hot-air curtains the calculation of air temperature in working rooms when opening gate or doors is carried out on the following indicators:
- easy physical activity – is not below 14 °C;
- average physical activity – is not below 12 °C;
- hard physical activity - is not below 8 °C.
In the absence of the constant places of work which are located directly at door openings, admissible air temperature can fall up to 5 °C.
Exhaust umbrellas. Are intended for catching of stream of harmful allocations with density, the smaller density of surrounding air. Work of umbrella will be effective when the amount of the air removed through it exceeds the volume of the air given by convective stream which appears over heat source at the level of arrangement of umbrella.
The sucking-away panels. These devices are intended for localization of the hazardous substances which are carried away by convective streams when fuller the shelter of sources of allocations is impossible for the technology reasons.
Panels mount sideways from source of pollution in vertical or slanting position. The distance from source to the panel has to be no more than width of source, at the same time length of the panel is accepted as two are long source.
Onboard suctions. Devices which are intended for removal of harmful allocations from the surface of solution when under the terms of technological process the device of full shelters is impossible. It is most often applied in galvanic shops.
Calculation of industrial ventilation
Calculation and design of industrial ventilation depends on the following factors:
- nature of production;
- type of pollution and allocations;
- room space and operating time of machines;
- radius of allocations;
- air consumption.
In devices of the local exhaust ventilation the necessary air exchange is counted proceeding from condition of localization of the impurity which are emitted from source of their education.
In those shops where perhaps sudden release of toxic or explosive substances is provided mounting of emergency ventilation which works only as exhaust. Emergency ventilation has to be started remotely. As the equipment reserve and main communications of all-exchange industrial ventilation and also local suctions which work only in emergency operation are used.
Equipment for industrial ventilation
Mounting of industrial vent systems means use of the specialized equipment. When calculating some of its characteristics can change, but the main components remain invariable.
Ventilating ducts – special pipes which section and the size depends on amount of air which needs to be banished per unit of time. The overall performance of all system depends on the correct design of channels, on them air is transported on object.
- Channels can be manufactured of plastic, aluminum, metal and other materials.
- Fans – the main component of any system of air circulation, provide necessary power and also set moving direction of air streams.
- Shaped parts – as well as pipes, can be made of plastic, creations of their turns and forks serve for connection of channels.
- Filters – the industrial filter can detain large and small impurity which inevitably are airborne any industrial constructions. For calculation of the required type of the filter it is necessary to know how dirty air on object.
- Recuperators – the difference of the industrial ventilating recuperator from household is that per unit of time it is capable to warm bigger amount of air.
- Conditioning systems – such systems should be equipped ventilation if you want air at the enterprise to be not only clean, but also fresh.
Advantages of mechanical industrial ventilation
The systems of industrial ventilation which use specialized ventilation equipment for ensuring effective air exchange are much more effective and can brag of the advantages. Bolshaya Square of coverage – industrial forced-air and exhaust installations use special powerful fans which provide intensive air stream.
- The efficiency – work of industrial ventilation system does not depend from any external conditions.
- Additional opportunities – the ability of forced-air and exhaust systems to filter air on objects, to moisten it or to drain belongs here.
- Target giving of air streams – at the correct design and mounting is perhaps directed to give fresh air directly to jobs.
- Increase in safety of work – ventilation of industrial facilities of compulsory type can catch and delete from air in the industrial room hazardous substances, dangerous gases, purify air masses.
- Possibility of carrying out installation works in buildings how their construction is completed. It favourably distinguishes mechanical ventilation from natural in which design it is necessary to be engaged on projecting phase of all building.