负压气力输送系统（稀相）
一种气力输送系统，适合于将粉状或粒状物料从多个起始点输送到一个目标点。也称为真空输送系统。
负压输送系统可以定义为采用吸气的方式沿限定通道输送粉状或颗粒状物料的方法。因输送管道内气体的压力为负值而得名.
特点
▲不需要旋转阀。
▲可以从数个起始点向一个目标点输送。
▲物料在常压下进人管道因而物料加人比较容易。
▲输送过程中不需要对输送气体进行冷却。
▲即便管道连接和密封不好,也不会造成粉料外泄。
▲物料接收料斗始终处在负压状态，需要考虑耐负压性能。
▲**输送压力只有-0.4到-0.5kPa，因而输送距离和输送量受到限制。
▲几乎无法实现密相输送。
▲比较正压输送，同样条件下能量消耗较高。
Negative pressure pneumatic conveying system (dilute phase)
A pneumatic conveying system suitable for transporting powdered or granular materials from multiple starting points to a target point. Also known as vacuum conveying system.
Negative pressure conveying system can be defined as a method of conveying powdered or granular materials along a limited channel by suction. Named after the negative pressure of gas in the pipeline
characteristic
▲ No need for a rotary valve.
▲ It can be transported from several starting points to one target point.
The material enters the pipeline under normal pressure, making it easier to add the material.
During the transportation process, there is no need to cool the transported gas.
Even if the pipeline connection and sealing are not good, it will not cause powder leakage.
The material receiving hopper is always in a negative pressure state, and the negative pressure resistance performance needs to be considered.
The conveying pressure is only -0.4 to -0.5 kPa, so the conveying distance and amount are limited.
▲ It is almost impossible to achieve dense phase transportation.
Compared to positive pressure conveying, energy consumption is higher under the same conditions.
