Address：No. 78, Daxiang, Zouqu Town Industrial Park, Zhonglou District, Changzhou, Jiangsu
Pneumatic conveying system introduction
Pneumatic conveying is also called air conveying. Under certain conditions, the air flow is utilized as a carrier medium. A method of transporting powder and granular solid materials in a pipeline. The system is mainly composed of sending equipment, conveying pipeline, gas separation equipment, gas source and purification equipment and electrical instruments. The flow state of the material in the pipeline is very complicated, and varies greatly with the speed of the gas stream and the amount of material contained in the gas stream and the material properties of the material itself.
Pneumatic conveying system compared with traditional conveying methods
In summary, pneumatic conveying has the following characteristics:
1) The conveying pipeline can be flexibly arranged, so that the process configuration of the plant equipment is reasonable;
2) Realizing bulk material transportation, high efficiency, reducing packaging and handling transportation costs;
3) The system is sealed, the dust is flying freely, and the environmental sanitation is good;
4) Less moving parts, convenient maintenance and easy to automate;
5) It can avoid the moisture, dirt or other impurities in the material, and can guarantee the quality of the conveyed materials;
6) A variety of process operations, such as mixing, crushing, grading, drying, cooling, metering, dust removal, etc., can be realized during the conveying process;
7) It is possible to carry out long-distance operation from a centralized point to a place to be distributed to a number of points;
8) For materials with unstable chemical properties, inert gas transport can be used.
Although to a certain extent, the power consumption may be slightly larger than other forms of transport, due to the high conveying wind speed, local wear may occur and a small amount of broken material may be generated. However, the above deficiencies can be significantly improved by using suitable conveying methods such as low conveying speed and high mixing ratio conveying.
Pneumatic transport status classification
According to the state of pneumatic conveying, when the gas-solid two-phase flow, the movement state of the material changes with the change of the conveying wind speed. When the wind speed of the material is high, the material is in a suspended state and is uniformly distributed by the airflow; as the conveying wind speed decreases, the materials begin to agglomerate; after that, some materials gather in the pipeline and are dynamically transported by the group pulse; continue to reduce the conveying wind speed. The material is blocked in cross section, forming an unstable material plug. At this time, the material plug is pushed by the pressure of the air; then the conveying wind speed is lowered, and the unstable material plug is turned into a stable material plug, which is driven by the pressure of the air.
It can be considered that the boundary of the material in the vertical pipe is uniformly distributed and the boundary of the material in the horizontal pipe is the boundary between the dilute phase and the dense phase, so the economic speed line can be regarded as the boundary line between the dilute phase and the dense phase.
In comparison, the whole pneumatic conveying system can be divided into the following two categories.
A. Dilute phase pneumatic conveying, the airflow speed is high, the material suspension is evenly distributed in the vertical, and the flying state is in the horizontal conveying, and the void ratio is large. The material is transported mainly by the energy held by the higher velocity airflow.
B. Dense phase plug flow pneumatic conveying, the material is no longer evenly distributed in the pipeline. It is dense, but the pipes are not blocked by materials. Therefore, it is still transported by the energy held by the airflow. Devices with such flow conditions are designed for high pressure and fluidized transport.
The conveying mechanism and application practice from pneumatic conveying show that it has a series of advantages: low film, environmental protection, high conveying efficiency, overall flexible equipment structure, convenient maintenance and management, easy automation and environmental protection. In particular, it can be used to combine the conveying process with the production process when transporting inside the workshop, which helps to simplify the process. To this end, labor productivity, cost reduction and land occupation can be greatly improved.