The negative pressure dilute phase pneumatic conveying system utilizes a gas pressure of less than 1 kg/cm2, and uses a negative pressure (four delivery type) with a higher speed to suck materials through the entire conveying line. Therefore, this conveying method is called a low-pressure high-speed system, which has a higher gas material ratio.
The negative pressure dilute phase pneumatic conveying system uses a negative pressure roots pump as the power source. The pipeline conveys a low vacuum pressure, with a wind speed of about 10-35 per second, and the material in the pipeline is in a fog shape. At the beginning of the system, there is an acceleration of about 10 m/s, and at the end, it can reach a high speed of 30 m/s, so the air flow velocity is high. The initial pressure of the transmission pipeline is basically close to atmospheric pressure, while the end pressure is generally between -0.01-0.06 mpa. When the negative pressure dilute phase pneumatic conveying system is started, the material within the storage volume is quantitatively supplied through the rotary lock gas supply valve, and is accelerated after being mixed with the negative pressure air flow generated by the Roots vacuum pump in the pipeline. The solid gas two-phase flow is used in the conveying pipe to form a relatively stable flow pattern and is lifted into a remote integrated filter separator. The mixture of air flow and material is forced to change its operating trajectory after entering the wall of the cyclone separator, Due to the fact that the density of solid materials is much higher than the density of gas, a very high centrifugal force is generated, which causes the materials to lose the speed of linear motion after entering the cylinder wall. Under the action of gravity, they fall into the cone of the cyclone separator, and then are uniformly fed to the downstream production equipment through the rotary lock gas discharge valve of the cone. The power source of the negative pressure dilute phase system uses a Roots vacuum pump, The gas can be filtered atmosphere or dried and purified gas. The above materials are transported in a fully enclosed manner.
Characteristics of negative pressure dilute phase pneumatic conveying system:
1. The delivery vacuum pressure is lower than the ambient pressure, even if the pipeline is damaged, it will not cause material leakage and cause vapor pollution to the environment;
2. The manufacturing and maintenance requirements of equipment are low, and the operability of workers is strong: it can be transported over long distances;
3. The conveying gas (generally air) is directly taken from the white atmosphere, and the temperature of the gas is the ambient temperature; Pipeline materials have a certain friction temperature rise;
4. The conveying is continuous and can also be interrupted. The wind speed in the pipeline is high, and there is no material accumulation;
5. It can achieve multi-point feeding and unloading;
6. The gas power source is generally vortex tea or Roots vacuum polymerization, without direct contact with materials. Long service life;
7. Strong responsiveness to conveying materials, enabling smooth conveying of both powder and particle materials; Especially suitable for self adhesive materials;
8. Low environmental pollution, but high requirements for dust removal area.
Basic parameters of negative pressure dilute phase pneumatic conveying system:
Air velocity: 10m’s – 35m/s,
Conveying capacity: 2-8t/h,
Conveying distance: 20-100m,
Conveying height: 10-30m,
Air source type: Roots vacuum pump.
