【 Weak current college 】 building ventilation basics

<br> <BR> First, the concept and role of the ventilation system is to <BR> building ventilation buildings contaminated indoor air purification, directly or through the back to the outdoors, and then added in fresh air, to maintain the indoor air .environment meet the health standards process. .Visible, ventilation is one of the ways to improve air conditions, it is excluded from polluted indoor air and fresh air to the interior of two, the former called the exhaust, which is known as the air supply. .Exhaust and supply air to achieve a range of used equipment, devices, called the total ventilation system. .) <BR> Building ventilation is often used in the production and life, the former is known as industrial ventilation. .<BR> Second, the ventilation system in the form and classification <BR> ventilation system can be divided into natural ventilation and mechanical ventilation. .Natural ventilation is the use of the room, the density difference between hot and cold air and the room windward side, leeward side of the air pressure level to the exchange; mechanical ventilation is the use of ventilation equipment to the workshop (room) into or discharged within a certain amount of air, .the air exchange and processing. .According to the different range of <BR> ventilation, mechanical ventilation can be divided into general ventilation, local ventilation and mixing ventilation of three. .Which mainly depends on ventilation using harmful substances produced and spread the scope of the size of the large area of harmful substances is a comprehensive air, on the contrary can be partial and mixed ventilation. .<BR> During the calculation of natural ventilation, usually referred to as the external walls of the pressure difference inside and outside the residual pressure on both sides, such as a fenestrae and pressure is positive, fenestrae ventilation; residual pressure is negative, the fenestrae into the wind; when .fenestrae inthe residual pressure of zero isobaric surface, then the upper part of fenestrae into the wind, the lower part of the exhaust. .In buildings, will be zero residual pressure in the plane and the plane is called, therefore, located in and below the surface of fenestrae is a ventilation window, located above the surface of fenestrae, and is into the wind window. .<BR> Natural ventilation under hot, is the use of indoor and outdoor air temperature, the formation of different density, the pressure difference caused by indoor and outdoor air exchange. .When the building by the combined effect of wind and hot, in the role of buildings on the periphery of the hole is equal to its internal and external pressure by the wind and the hot sum. .Full use of wind, natural ventilation under hot modern green building is one of the important is to improve the indoor air quality, and create a comfortable environment, one of the measures take precedence. .<BR> Major equipment mechanical ventilation fans, air tube or air duct, air valve, air and dust removal equipment. .<BR> One fan <BR> 1. .Classification <BR> fan ventilation system for the fan is the flow of air in the course of transmission power to overcome the resistance loss of machinery and equipment. .In ventilation engineering is the most widely used centrifugal fans and axial fans. .By the centrifugal fan impeller, casing, drive shaft, the suction port and exhaust port and other parts. .<BR> 2. .Technical performance of the fan air flow <BR> <BR> ①: refers to the fan in operation, the amount of air delivered per unit time, in units of m3 / h; <BR> ② pressure: pressure generated by the wind turbine, in units of Pa .; <BR> ③ effective power: that fans send air power, which is equal to the product of air volume and pressure, in units of W. . <BR> Second, the ventilation ducts <BR> 1. .Duct materials and metallic materials <BR> it points to two major categories of non-metallic materials. .<BR> <BR> ① sheet metal material, stainless steel, aluminum and so on. .<BR> ② non-metallic materials with a glass plate, PVC board, concrete air duct and so on. .<BR> 2. .<BR> Duct cross sectional shape, round and rectangular two. .<BR> Third, the air valve <BR> valve installed in the duct or duct, primarily for regulating the air flow. .Valve in the ventilation system can be divided into a control valve, valves and automatic control valve. .'<BR> IV <BR> air intake and outlet sub-exhaust ports, mounted in the wind, the two ends of pipe or duct, according to different occasions, is divided into two forms of indoor and outdoor. .<BR> V. <BR> equipment to prevent dust pollution in the air from the atmosphere prior to purification, so that dust and air separation, process equipment such as dust removal equipment. .Main types of dust removal equipment, mechanical filter, filter type dust collector, wet scrubber, and four types of ESP. . <BR> <BR> <BR>.