Also known as pneumatic conveying air transport, the use of the energy flow in a closed flow direction along the conveying duct granular material, the fluidization technology, a specific application. Pneumatic conveying equipment, simple structure, easy to operate, can be used for horizontal, vertical or inclined conveying direction, during transportation of materials can be carried out simultaneously heating, cooling, drying and air classification and other physical operations or certain chemical operations. Compared with mechanical transmission, this method of energy consumption of large particles susceptible to breakage, equipment is susceptible to erosion. Water content and more, there is adhesion or in high-speed movement of the material is easy to produce static electricity, unfit for pneumatic conveying. Particles in the pipeline according to the intensity, pneumatic conveying divided into: ① dilute phase conveying: solids content of less than 1-10kg/m3, higher gas velocity (about 18 ~ 30m / s), substantially in the 300m transmission distance less. Now mature material sealed pump equipment, the transport operation is simple no mechanical moving parts, delivery pressure is low, no repairs, maintenance-free! ② dense phase conveying: 10-30kg/m3 solids or solid-gas ratio greater than 25 transport process. Operating gas velocity is low, with a higher pressure pressure feed. Now mature equipment sump pumps, transmission distance of 500m or more, suitable for more dollars from the transportation, but this device more valves, pneumatic, electric equipment and more. Delivery pressure is high, all piping required wear-resistant materials. Intermittent pneumatic tank dense phase conveying. The particles are added portionwise pressure tank, then ventilation blowing loose until the tank up to a certain pressure, play an open valve, the particulate material in the conveying pipeline blown. Pulse is an air transport pass into the next tank, the material blown loose; another unit frequency is 20 ~ 40min-1 pulse stream of compressed air blown conveying pipe inlet formed in the pipe material are arranged alternately short column and short column, by the air pressure pushing forward. ③ vacuum conveying: pipe pressure below atmospheric pressure, suction feed, subject to discharge under negative pressure, can be transported shorter distances; advantages: investment in equipment, the load is small. Disadvantages: Running velocity is high, piping badly worn, worn loopholes undetectable! Carried out in a horizontal dilute phase conveying pipeline, the gas velocity should be higher, the particles suspended in the air stream. The gas velocity is reduced to a critical value, the particles will start in the lower part of the wall deposition. This critical gas velocity is called the deposition rate. This is the dilute phase horizontal transport gas velocity limit. Superficial gas velocity is less than this value, the tube deposits occur within the flow channel cross-section reduction, based upon the deposited layer over the deposition speed airflow. Upward in a vertical pipe for pneumatic conveying, higher gas velocity particles suspended in the air stream. In the constant volume particle transport, the lower gas velocity, solids content of the pipeline will increase. When the gas velocity is reduced to a critical value, the air is not so dense particles uniformly dispersed particles merge into the plunger shape, there slugging phenomenon (see fluidization), the pressure drop dramatically. This critical speed, said choking speed, which is when the dilute phase conveying vertically upward gas velocity limit. For a uniform particle size, the deposition rate and choking velocity roughly equal. However, there are some on the particle size distribution of the material, the deposition rate is choking 2 to 6 times the speed. Material sealed pumps, wet mixer, pneumatic conveying equipment, silo top filter, 508 release valve, bulk machine http://www.zzgaotie.com