Dust control by removing it with suction air, as is known, is called aspiration.
Aspiration distinguish two cases kapsyulyatsii hearth dust:
a) full shelter in a solid casing, having no other openings, except techek;
b) incomplete cover, when the housings have slots and holes.
Fig. 8. Capacious collapsible shelter in place of falling material
1 - estrus, 2 - screw, .3-capacious shelter; 4 - aspirating funnel
In the first case, when the shelters are tight or are close to those inside the shell creates a vacuum. Podsos through heat, through leaks gaskets, seals and through, etc. create airflow inside the casing and remove the portion of the resulting dust. If the vacuum is sufficient and the rate of leaks does not allow dust particles moving at great speeds, break out, achieved complete dedusting. Vehicles, having complete housings include elevators and screw conveyors, some mills and magnetic separators, Truck scales, mixers, and other mechanisms that do not require maintenance.
Consider the aspiration of the casing elevator. Steel casing usually consists of links connected by a bolt, with gaskets between flanges. Inevitable gap between the pads through which the presence of positive pressure in the shell knocked the dust. Positive pressure (in the absence of aspiration) is created at the bottom of the casing in place of admission to his material, due to air entrained material. The greater the drop height and the more material is filled into heat, the more positive pressure.
Knocking the dust is not only due to pressure. Partially knocked the dust due to the forces of inertia of the material and its elasticity. Dust particles acquire kinetic energy from moving in directions that do not coincide with the movement of air flow inside the enclosure. The foregoing only schematically discloses the physical phenomena occurring in the casing elevator. The reality is much more complicated.
Distinguish feed elevator hot and cold material. When the hot material flowing in the housing phenomenon is further complicated by convection currents of heated air. However, the common perception among experts believed that the hot material should not be sucking from the bottom (the shoe), an elevator, not justified n refuted practice. Only for very low grain elevators (the height of no more than 8-10 m) may restrict suction only from the head. When elevators height of more than 10 m should provide suction from the shoe and from the head, regardless of the degree of heating of the material.
When there is incomplete shelter deposition chamber or the circumstances of technology required openings, dedusting complicated. When it is impossible gidroobespylivaniya want to suck large amounts of air, but it does not always reach the goal.
The design of the shelter and proper adherence to his aspiration funnel play a crucial role. Typically, shelters are made of sheet steel of thickness 1,5-2 mm with the frame of the corners. The connection of separate parts made on the felt or rubber pads.