Fixed type asphalt batching plant with 2-stage duster and 50T hot aggregate storage bin
Duster system introduction
A. Summarization
The dust collecting equipment is a secondary system. Grade 1 duster is dust collector cyclone; grade 2 duster is a baghouse. It is used to collect excessive dust, and eliminate floating coarse grain.
Coarse grain collected by grade 1 duster is delivered to hot aggregate elevator through screw conveyor.
Thin dust collected by baghouse is delivered to lame filler hopper through screw conveyors and bucket elevator, or discharged outward through screw conveyors when the dust is excessive or contains too much mud.
B. Grade 1 duster
This duster collects coarse dust through changing direction of air current and angle of adjustable guiding-board. Although there is not moving part, but it also can achieve manual adjustment through loosing the bolt of guiding board and displace it to one of its three position.
Notice
The adjustment of guiding board is critical, and this is often being done during use. Because any adjusting will influence the characteristic curve of air current, so, refer to our technology department before carrying through any adjustment.
Collected dust falls into the hopper under segregator, then conveyed to hot elevator.
C. Baghouse
. Summarization of operation principle
Negative pressure in the plenum above pulls the dust-laden air through the filter bags. The fine dust collects on the outsides of the bags.
This duster contains two parts, the upper part is mainly inner steel framework supported filter bags, which hanged up to clapboards, bottom-close, and top-open to atmosphere. Negative pressure pulls the dust-laden air through the filter bags. The fine dust collects on the outsides of the bags. Along with increasing of exterior-gathering dusts, the resistance of air flow increases gradually. So, it is necessary to clean these bags. The counterblow system depends on pressure differential to make dust fall, and the counterblow duration of each bag is 1.9s. the interval of this periodical job can be adjusted through FX calculagraph. Commonly, this interval is about 30s.
| Some limits for using baghouse | |
| 1 | The baghouse is designed to be fit for prescriptive maximum air flow. Unlike cyclone or wetting-duster, if the airflow is larger than maximum to some extent, such as 10 percent, serious holdback will occur. So, it is necessary to control the airflow through adjusting electric-promoted air door of exhaust fan. |
| 2 | Baghouse is adaptive to relative dry air. Be sure to keep the airflow temperature above dew point, otherwise, there will form mud layer on bags, which influence standard airflow. |
| 3 | the upper limit temperature for Nomex fibre is 210. Generally, temperature sensor, which can indicate air temperature and transfer the valve to director, is installed on the inlet of baghouse. To prevent overheating, it is necessary to preset a temperature value 120 at director, and automatically open cold-wind valve as temperature reaches the value. |
| 4 | After a longer stop, especially the first running of one day, it is necessary to warm-up and dry this system to eliminate coagulation. |
| 5 |
Air pressure may fall due to some cause, such as coagulation or lack of counterblow. It is needed to revise this error before continuous operation, or bags will be badly damaged.
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Notice
All these limits on baghouse are just our basic operation rules. Be sure to observe carefully and comply with these rules, so as to get continuous operation and avoid replacing expensive bags.
