rate in outdoor air intake ducts
Air velocity in the outer suction channel is recommended in the range of 10 to 14 m / sec. At such speeds the pressure loss is relatively small, and the fan is stable. Energy consumption in the suction system is much smaller than at injection.
If the device can not be a central inlet system, the contaminated gas and vapor atmosphere of the industrial site may have to resort to washing the fresh air in the spray chamber followed by a secondary air preheating. Of course, such washing is effective only for gases and vapors are soluble in water, such as acid vapors, nitrogen oxides, etc. Cleaning the air is produced by an adiabatic process of recirculating water. A substantial portion of gas contamination is washed with water.
Cleaning the fresh air of the mercury vapor is sometimes used in enterprises of mercury metal, usually on older plants, where the soil of the industrial site "contaminated" with mercury. Purification by filtering incoming air through a layer of natural manganese dioxide - pyrolusite. Thickness of the pyrolusite is taken from 200 to 500 mm, grain size 6-10 mm, the content of RID in pyrolusite must be at least 85%. At a special grate fit wire mesh, which is poured evenly pyrolusite. The rate of passage of air through a filter made from 0,15 to 0,25 m / sec, with bandwidth of 1 m2 of filter is from 550 to 900 m3 / h. The degree of purification to 99%. Resistance from 60 to 150 kg/m2.
Pirolyuzitovye filters - the cumbersome installation. To reduce the area occupied by them doing multistage filters, as shown in Fig. 32. It should be noted that pirolyuzitovye filters work well only when humidity not exceeding 80%.
Supply plant to clean the air of gases and vapors should operate all year round. In the areas they serve, the window does not open.
Local air supply chamber in buildings where there are toxic hazard, as a rule, should have access to the outdoors-. When this is not feasible under the terms of planning, is allowed to communicate with the inlet chamber production facilities only through lobbies. In the chamber is recommended to serve incoming air to create a backwater is the amount of no less than two-fold.
Submission of fresh air in a room with a gas hazard is usually carried out in the working area with diffusers with uniform distribution of. Concentrated flow is unacceptable. The air must be submitted in place of the most frequent and long-stay people.
In some cases, the inlet air is partially fed as air showers. Those parameters are arranged locations of significant exposure for large volume production
the number of permanent jobs, as well as in cases where not possible with the help of local suction to ensure normal sanitary conditions in the workplace. Air dushirovanie usually handled by outside air. Air showers with recirculation of air craft almost do not apply.
In areas with toxic hazards in the absence of permanent jobs it is recommended to arrange a special cab - recreational running. In these cabins is supplied treated by purified air.