Damper: both gas flow regulating button and wind board are high grade PP material, connected with 304 stainless steel bar, manually adjust the outside valve knob, control air flow.

气流调节阀：气流调节扭与挡风板均为高密度PP材质，用304不锈钢方棒连接，手动调节外部阀门旋钮，控制气流量。

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Relay valves convert a sustained air flow from a three-way pilot valve into a momentary pulse or bleed, which shifts a control valve and then closes.

延迟阀可调节从三通控制阀到瞬间脉冲或放气阀的空气流量，放气阀或瞬间脉冲改变控制阀，然后关闭。

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Of large air-conditioning system, using the manual control valve regulating the complex process of manually adjusting the front-end valves, back-flow will be affected.

对大型空调系统而言，采用手动调节阀调节过程复杂，手动调节前端阀门，后端流量会受影响。

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