Industrial ventilation is one that uses fans in machinery and industrial processes, providing air, cooling machines or parts, or extracting fumes, among other applications. When choosing the ventilation system that best suits you, you must consider several characteristics to be able to make sure that you are making a good purchase such as the materials from which they are made, the assembly, the control system and the type. Within the market there is a great variety, from small ventilation equipment for industrial spaces to huge equipment for tunnels and mines.
Ventilation in industrial buildings
Industrial buildings are common workplaces where it is easier to run into ventilation problems. Unfortunately, the ventilation of these ships is normally obsolete by the passage of time, or is damaged, or does not work, or directly shines by its absence.
Recommendations for ventilation in industrial buildings
Consequently, it proposes to carry out a number of renovations / hour at the volume determined to ventilate the enclosure, replacing all the air inside a certain number of times every hour. Depending on the volume of the ship and its conditions, this number of renewals / hour could vary between 4 and 10 renewals per hour.
An example that could be given to this case, in the term of small warehouses where we have a very vitiated environment, 10 renewals per hour could be applied directly, while in larger industrial warehouses that have the purpose of storing product, it is usually of large dimension, it is usually sufficient to apply 4 renewals per hour.
Design of the ventilation system in industrial buildings
In the design of the ventilation of industrial buildings it is very important to take into account the installation of the ventilation system. For any ventilation system to function properly, apart from establishing the necessary air flow and the type of fans, one or several points must be determined where the air is to be expelled to replace the extracted one, but located in such a way that The air flow that will be created between the inlets and the extraction points is sufficient to avoid possible.
Ventilation systems in industrial buildings are usually made up of one or more extractors, which can be wall-mounted helical fans, or helical fans to be installed on the roof. Being composed of a helical or axial propeller, these types of fans work with very small load losses so that their installation is usually several grilles, normally installed on the doors of the same ship.
If a non-diaphanous spacecraft is available, in order for ventilation to be effective and all rooms can be ventilated, a centrifugal fan (normally located inside an acoustic insulating box) must be used, since this type of fans work with high load losses.
On the other hand, it is important to note that if there are particular elements in the ship that produce fumes or harmful gases, smoke collection systems must be provided for each of these processes. An example could be the typical welding zone that many ships have and that must have, in addition to the general ventilation system of the ship, an independent ventilation system for this process.
Finally, if there is an office area in the industrial building, it must apply what the RITE considers.
Regulations for ventilation of industrial buildings
While it is true that there is no clear regulation regarding industrial buildings, air quality is essential and that it must respect a minimum so that the worker breathes adequate air within the possibilities of the ship. There is only one decree in which the regulations include industrial buildings, the RD-427. In this Decree, with a few years old, it is detailed that in industrial buildings a renewal of 30 m3 / h per worker should be applied in case of a ship in which there are no tobacco fumes, while 50 m3 / would be applied h per worker in case of being in an industrial building with smoke problems.
The ventilation proposed by this standard is usually quantitatively and qualitatively insufficient since we can find ourselves perfectly in an industrial warehouse with a very vitiated environment in which 20 people work and the ship instead is 2000 m2. Logically, the values that the RD-427 handles are usually insufficient.
Maintenance of an industrial ventilation system
To contribute to the efficiency of the industrial ventilation system, close attention should be paid to evacuation hoods and their design. Taking as a starting point the specific characteristics of the ventilation equipment.
Similarly, for the industrial ventilation system, proper maintenance is required with programming based on good time frequencies, to avoid breakdowns in equipment that can be detected in time before they generate significant consequences. This maintenance could be accompanied by health programs applicable to employees in that area.
It is important to properly maintain the ventilation equipment to ensure its operation and prolong its life. Maintenance tasks should be performed in general at least every 3 months or when the facilities are emptied for cleaning.
Axial Industrial Fans
A fan is considered axial when air enters and leaves the fan along a path parallel to the axis of the propeller. In axial fans the air is driven by a propeller equipped with a variable number of blades that are anchored in a core or hub that is the element that transmits the energy of the shaft to the blades.
The difference that axial fans have against centrifuges is that they are suitable for when it is required to move a lot of air flow with relatively low pressure. Thus, we will use them either by swallowing air freely or in facilities where there is little loss of load.
Performance of an axial fan
The performance of this type of industrial fans depends on many parameters of the fan itself, below are the most important parameters to look at before buying an axial industrial fan. As more significant parameters we can mention: the diameter, the revolutions, the angle of the blades and their number and width.
If we follow what the laws of the fans say, the flow rate increases cubically with the diameter, that is, if we double the diameter and keep everything else unchanged, the flow rate will be multiplied by 8. The pressure is related to the diameter chart. At double diameter we have 4 times more pressure.
Using the aforementioned laws, we see that the flow rate is proportional to the number of revolutions per minute and the pressure is proportional to the square of the revolutions.
Diameter and rpms are the two parameters that, by far, most influence the performance of axial fans.
- The angle of the blades. The blade angle is defined as the angle of the chord at the end of the blade with respect to the axis of the fan. Well, the flow grows linearly with the sine of this angle. We could say that by increasing the angle of the blades, the section in green of the characteristic curve of the figure shifts to the right, staying parallel to the initial one, however the pressure at which the unstable zone begins decreases, that is, the point D goes further to the right but descends somewhat.
- Number and width of the blades. If keeping the angle of the blades, the diameter and the rpms, and what we do is add more blades (or we keep their number but we put them wider, which for the case is the same since both changes produce the same effect), the flow hardly changes, the green area of the curve remains in the same place but lengthens, that is, the useful area of the fan increases, point D moves upwards.