如果主排气扇出现故障，则备用排气扇将启动。

An optional backup vent fan operates in the event of a primary vent fan failure.

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增加一个桨叶(主桨有5个叶片，尾桨有4个)，并使用了改进的排气系统。

Adding a rotor blade (it had five on the main rotor and four on the tail) and using a modified exhaust system were among them.

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烘干部分：(干燥机)由输送辊、减速机、托辊链条、链轮、主风道、回风道、排气系统及分配器组成。

Drying part: drier including conveyor roller reduction drive roller chain wheel main wind channel circle wind channel exhaust and distributor.

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