正压输送

Via pressure blowing or vacuum suction, pneumatic conveying systems can be divided as pressure system and vacuum system.

Pressure system is more common is higher conveying capacity and longer conveying distance as there is higher pressure source available while vacuum system is only up to max. 1 bar pressure drop.

Pickup device for pressure system could be an airlock (rotary valve station), a blow tank (pressure vessel), a dual flap or dual butterfly valves or an venturi ejector, depending on actual plant application.

通过正压吹扫还是负压抽吸，气力输送可以区分为正压输送系统和负压输送系统。

正压输送系统适合更大的输送能力和更长的输送距离，因为正压风机可以达到更高的压力，而负压风机最高也只不过一个公斤的压差（即接近绝对真空时、实际无法达到）。

正压输送取料点可能是一个气锁站（旋转阀输送站）、发送罐（压力罐）、双翻板阀或双蝶阀，或者是一个文丘里发射器，取决于实际应用。

Advantages of Pressure Conveying System 正压输送的优势

• Pressure systems are more efficient; lines sizes, blowers, and destination filters are usually smaller and less costs 通常正压输送更有效率，输送管径、风机、末端气固分离除尘器都会更小，因而投资更低

• At the destination: 在终点处

• Easier for multiple destinations (just need diverter valve or hose switch) 适合多终点输送

• Less costs (the bin vent filter doesn’t see much pressure or vacuum) 末端除尘器无须带压，成本低

• Less head height 高度更低

Disadvantages of Pressure Conveying System 正压输送的劣势

• At the source: 在起点处

• Need Aerolock: more costs and more head height 需要锁风旋转阀，成本更高、高度要求更高

• A source Aerolock is prone to wear 旋转阀可能会磨损

• Dust and air leakage above the Aerolock must be considered 旋转阀的泄露风量需要考虑在内

• Any leak in a pressure system will cause material to escape 系统如果发生泄露，物料将会逸出

• A pressure blower / compressor heats the conveying air (can be corrected with an aftercooler) 输送风机或压缩机产生的热风可能会加热物料（因此可能需要在其后配置空气冷却器）