Ventilation improves the air environment of the workshop. On the one hand, the polluted air which does not meet the hygienic standards is discharged outdoors in some places or the whole workshop. On the other hand, fresh air or purified air which meets the hygienic requirements is sent into the room. We call the former exhaust and the latter intake.

　　如果只對局部地點進行排風或送風，即局部通風；如果對整個車間進行排風或送風，則為通風。通常，按通風系統的作用范圍不同，可將通風分為局部通風、通風和事故通風。局部通風系統又分為局部進風和局部排風兩大類，它們都是利用局部氣流，使局部工作地點不受有害物的污染，造成良好的空氣環境。

　　If ventilation or supply is only carried out at local locations, that is, local ventilation; if ventilation or supply is carried out throughout the workshop, it is full ventilation. Generally, ventilation can be divided into local ventilation, comprehensive ventilation and accident ventilation according to the different scope of action of the ventilation system. Local ventilation system can be divided into local air intake and local air exhaust. Both of them make use of local air flow to protect local working places from harmful pollutants and create a good air environment.

　　（一）局部排風

　　(1) Local exhaust

　　在集中產生有害物的局部地點，山東通風管道設置捕集裝置，將有害物排走，以控制有害物向室內擴散，這種通風方法稱為局部排風。這是防毒，排塵有效的通風方法。

　　In local places where harmful substances are concentrated, ventilation pipes in Shandong Province set up traps to remove harmful substances to control the indoor diffusion of harmful substances. This ventilation method is called local exhaust. This is the most effective ventilation method for anti-virus and dust removal.

　　山東通風管道

　　Shandong Ventilation Pipeline

　　局部排風系統由以下幾部分組成：

　　The local exhaust system consists of the following parts:

　　（1）局部排風罩

　　(1) Local exhaust hood

　　局部排風罩是用來捕集有害物的。它的性能對局部排風系統的技術經濟指標有直接影響。性能良好的局部排風罩，如密閉罩，只要較小的風量就可以獲得良好的工作效果。由于生產設備和操作的不同，排風罩的形式是多種多樣的。

　　Local exhaust hood is used to trap harmful substances. Its performance has a direct impact on the technical and economic indicators of the local exhaust system. Local exhaust hood with good performance, such as airtight hood, can achieve good working effect as long as the air volume is small. Due to the difference of production equipment and operation, the forms of exhaust hood are various.

　　（2）風管

　　(2) Air duct

　　通風系統中輸送氣體的管道稱為風管，它把系統中的各種設備或部件連成了一個整體。為了提高系統的經濟性，應合理選定風管中的氣體流速，管路應力求短、直。風管通常用表面光滑的材料制作，如：薄鋼板、聚氯乙烯板，有時也用混凝土、磚等材料。

　　The pipeline that conveys gas in the ventilation system is called the air duct. It connects all kinds of equipment or components in the system into a whole. In order to improve the economy of the system, the gas velocity in the air duct should be selected reasonably, and the pipeline should be short and straight. Air ducts are usually made of smooth surface materials, such as thin steel plate, PVC board, and sometimes concrete, brick and other materials.

　　（3）除塵、凈化設備

　　(3) Dust removal and purification equipment

　　為了防止大氣污染，當排出空氣中有害物量超過排放標準時，必須用凈化設備處理，達到排放標準后，排人大氣。凈化設備分除塵器和有害氣體凈化裝置兩類。

　　In order to prevent air pollution, when the amount of harmful substances in the discharged air exceeds the discharge standard, it must be treated with purification equipment, after meeting the discharge standard, discharging into the atmosphere. The purification equipment can be divided into two categories: dust collector and harmful gas purification device.

　　（4）風機

　　(4) Fans

　　風機向機械排風系統捉供空氣流動的動力。為了防止風機的磨損和腐蝕，通常把它放在凈化設備的后面。

　　The fan captures the power of air flow from the mechanical exhaust system. In order to prevent the wear and corrosion of the fan, it is usually placed behind the purification equipment.