Working Principle of Baghouse Dust Collector for Crushers in Stone Crushers

 When dust-laden gas enters the hopper through the air inlet, some coarse dust particles fall into the hopper due to inertial collision and natural sedimentation. Most dust particles rise with the air flow into the bag chamber and are filtered by the filter bags. The dust particles are retained on the outer surface of the filter bags, and the purified gas enters the box through the inside of the filter bags, then is discharged into the atmosphere through the valve plate holes and air outlet, achieving the dust removal effect. As the filtration process proceeds, the dust accumulation on the outer surface of the filter bags gradually increases, and the operating resistance of the dust collector also rises. When the resistance reaches the preset value (1200～1500Pa), the dust cleaning controller sends a signal. First, the lift valve closes the valve plate holes to cut off the filtration air flow and stop filtration. Then the electromagnetic pulse valve opens, and injects compressed air with a pressure of 0.5～0.7MPa into the box in an extremely short time (about 0.1 second). The compressed air expands rapidly in the box and surges into the filter bags, causing the filter bags to deform and vibrate. Combined with the effect of reverse air flow, the dust on the outside of the filter bags is removed and falls into the hopper. After dust cleaning is completed, the lift valve opens again, and the dust collector resumes filtration operation.

 The above working principle only describes the operation of a single chamber. In practice, the air box pulse baghouse dust collector consists of multiple chambers and rows of filter bags. During dust cleaning, each chamber is operated in sequence separately, which is called off-line compartment dust cleaning. Its advantage is that the chamber under dust cleaning does not interfere with the chambers in normal filtration, enabling long-term continuous operation. The process from the start to the end of dust cleaning for one chamber is called a dust cleaning cycle, which generally lasts 3～10 seconds. The time from the end of dust cleaning for the first chamber to the start of dust cleaning for the second chamber is called the dust cleaning interval. The duration of the dust cleaning interval depends on flue gas parameters and equipment model selection, ranging from tens of seconds to several minutes or even longer. There are two types of dust cleaning intervals: centralized and uniform. A centralized dust cleaning interval means that after the dust cleaning of the last chamber is completed, all chambers return to filtration status until the next dust cleaning cycle starts. A uniform dust cleaning interval means that after the dust cleaning of the last chamber is completed, the dust cleaning of the first chamber is initiated at the same fixed interval, so the dust cleaning process under uniform interval is continuous. The time from the start of the dust cleaning cycle of the first chamber to the start of its next dust cleaning cycle is called the total dust cleaning period, whose duration is determined by the length of the dust cleaning interval.

 All the above dust cleaning actions are fully automatically controlled by an imported Siemens PLC. There are two types of dust cleaning controllers: timed type and pressure-dependent type. The timed type presets a fixed dust cleaning interval based on the resistance change of the dust collector, and the dust collector performs dust cleaning according to this preset time. This type of controller features a simple structure, easy commissioning and maintenance, and low cost, making it suitable for working conditions with stable operation parameters. The pressure-dependent type is equipped with a pressure switch inside the controller, which measures the operating resistance of the dust collector through a pressure tap on the equipment. When the resistance reaches the preset dust cleaning value, the pressure switch sends a signal to activate the dust cleaning controller for dust cleaning.