Pneumatic conveying systems can be divided into three categories: suction type, pressure type and mixed type according to their device form and working characteristics.
(1) Suction type
The suction type pneumatic conveying device uses a ventilator to suck air and materials into the conveying pipe and transport them to the unloading location. It is often used for material transportation inside the workshop, as shown in Figure 11-1.
Material transportation is completed on the suction section side of the fan. The characteristics of this conveying method are: the conveying device works under negative pressure, which can not only convey materials, but also collect dust. Materials and dust will not escape and fly, ensuring the hygiene inside the workshop; it is suitable for materials to be transported from multiple locations. Concentrated transportation from place to place; suitable for conveying materials with a wide accumulation area or low or deep storage; the feeder structure is simple; the unloader has high sealing requirements, and the conveying volume and conveying distance are subject to certain restrictions. The cotton processing factory’s goods yard uses suction-type pneumatic conveying systems for cotton suction, cotton distribution, cotton collection, lint collection, scrap recycling and air distribution.
(2) Pressure-feeding type
The pressure-feeding pneumatic conveying device uses the air flow pressed out by the ventilator, and then mixes the material into the material for transportation when passing through the conveying pipe, as shown in Figure 11-2. The material conveying process is completed on the side of the compressor section of the fan.
The characteristics of this transportation method are: the feeding pipe is bifurcated and equipped with a reversing valve, which can change the transportation route or transport to several places at the same time; it is suitable for large flow and long-distance transportation; the entire device is under positive pressure, and the material can easily It is discharged from the discharge port, so the structure of the unloader is simple, but it is easy to cause dust to escape; the structure of the feeder is relatively complex.
Cotton processing plants rarely use pressure-feed conveying, which is generally used to convey cotton after stripping.
(3) Mixed type
The mixed pneumatic conveying device transports materials in both the suction pipe section and the pressure pipe section of the fan, that is, it is a combination of suction type and pressure feeding type, as shown in Figure 11-3 shown.
The hybrid pneumatic conveying device has the characteristics of both suction and pressure conveying. This conveying method is used for circulating lint cleaning in cotton processing.
The pneumatic conveying system of cotton processing plants generally consists of feeders, conveying pipes, unloaders, air closers, dust collectors, ventilators and other equipment.
AAAweqeqeasddqfrwerewgre
