Explosion-proof MC type explosion-proof pulse bag filter design for limestone mine

Explosion-proof pulse bag filter is a professional dust-collecting device developed on the basis of ordinary pulse Bag Type Dust Collector, combined with dust particle size, flammable and explosive. It has been widely used in China. The explosion-proof pulse bag filter adopts anti-static filter material. The body has an explosion-proof structure and is equipped with a pressure relief device. It has explosion-proof performance and is suitable for the collection of pulverized coal preparation system and flammable and explosive dust. The machine has fewer mechanical action parts, less maintenance work, and convenient bag change. Due to the use of pulsating cleaning, the explosion-proof pulse bag filter has high dust collection efficiency, long-term and high-efficiency operation, and dust collection efficiency of over 99.8%. It is widely used in dust collection of cement, electric power, metallurgy, chemical industry and other industries. 

1, construction

The dust remover consists of five parts: upper, middle and lower tanks, ash discharge device and spray cleaning system. The upper case includes a top cover and an air outlet that can be picked up. The middle box has a flower board, a filter bag assembly, an explosion-proof pressure relief valve, and an anti-static filter bag. The lower case has an ash bucket, an air inlet and an access door. The ash discharge device is a gravity discharge valve or a rotary discharge valve. The spray cleaning system consists of a pulse controller, an electromagnetic valve, a blow pipe and an air bag.

2, the working principle

(1) Filtration principle: Under the action of the main fan of the system, the dust-containing gas enters from the air inlet of the dust collector, passes through the airflow homogenizing device, and then enters the ash bucket downward. Due to the slowing of the flow rate, plus the inertia and the self-weight of the dust, the large particle dust in the gas is separated by the inertial force and falls directly into the ash bucket. The dust-laden gas enters the filter bag filtration zone after passing through the ash hopper, and the gas passes through the filter bag, and the dust is left on the outer surface of the filter bag. The purified gas enters the clean room through the filter bag mouth and is discharged from the air outlet.

(2) Principle of cleaning: As the filtration time is extended, the dust layer on the filter bag is continuously thickened, and the resistance is continuously increased. When the resistance rises to the set value, the cleaning device starts to clean. When cleaning, the compressed air passes through the pulse valves in sequence in a very short time, and is sprayed toward the filter bag through the nozzle, so that the filter bag rapidly expands to generate vibration, and adheres to the outer surface of the filter bag under the action of the reverse air flow. The dust was peeled off and dropped into the hopper.

(3) Dust collection: The dust that has been intercepted by filtration and cleaning is dropped into the ash hopper, and then discharged by the ash mouth.

How to prevent the explosion of the bag filter?

(1) Preventing the explosion of the bag filter - special design, in order to prevent the accumulation of flammable dust in the internal components of the bag filter, all beams, partition plates, etc. should be installed with dust-proof plates, and the slope of the dust-proof plate should be greater than 65 degrees. The horn of the ash bucket should not be less than 70 degrees. In order to prevent the ash accumulation phenomenon due to the small angle between the two bucket walls, the slats should be installed on the two adjacent side panels of the bag insulation pot to eliminate the deposition of dust. When the ash hopper condensation is blocked due to improper operation of the bag Chenjiang faucet and the dust humidity is high, when designing the ash hopper, the insulation layer or the tubular electric heater is added to the high temperature flue gas on the ash wall panel. In order to prevent ash hoppers, a side arm vibrator or air cannon is also required on the side of the hopper of each bag.

(2) Preventing the explosion of the bag filter - The selection of the Dust Filter Bag adopts the anti-static filter bag inside the dust collector. Since the high-concentration dust rubs against each other during the flow, the dust and the filter cloth also rub against each other to generate static electricity, and the accumulation of static electricity will occur. A spark is generated to cause combustion. For the pulse cleaning method, the polyester foam needle felt is used for the filter bag. In order to eliminate the polyester static needle, the conductive wire or carbon fiber is spun in the filter bag fabric. When the filter bag is installed, the filter bag passes through the steel frame. It is connected to the multi-well plate and connected to the grounding grid of the workshop through the housing. For anti-drying filter bags, we have a wide range of anti-static products. The effect is very good.

(3) Preventing the explosion of the bag filter - Setting the safety valve to set the safety hole (valve) is to limit the explosion to the inside of the bag filter without expanding to other aspects. It is important to set up safety holes and necessary fire-fighting equipment. The purpose of setting the safety hole is not to prevent the safety hole from exploding, but to limit the explosion range and reduce the number of explosions. Most Dust Collectors that handle explosive dust are operated with safety holes. Because of this, the design of the safety hole should ensure that in the event of an explosion, it can actually play a role; in general, it is necessary to strengthen the maintenance and management of the safety hole.

1. Preparation before commissioning

(1) Remove debris from the dust collector box and the ash discharge device.

(2) Check if the lubrication points are to be refueled.

(3) Check the wiring of the circuit control system.

(4) Check if the cleaning system is normal.

(5) Check the gas supply condition of the gas source and clean the gas path system with compressed air.

(6) Adjust the red spur of the explosion-proof valve to a gap of 1-2 mm from the diaphragm.

2, test drive

After all the inspections are complete, you can adjust the test car according to the following procedure:

(1) First connect the high-pressure gas source (if the high-pressure gas source is a separately set air compressor, the operating procedures should be operated according to the instructions of the air compressor), adjust the pressure of the gas storage tank to 0.5~0.7Mpa, check the compression. Whether the pneumatic components such as air pipe joints, triple joints, and pulse valves are installed tightly, then operate the switch of the electric control device, and input an action signal to the solenoid valve to check whether the pneumatic components are normal.

(2) Start the ash discharge device and check if it meets the work requirements.

(3) Under no-load, start the fan, slowly open the fan control valve to meet the process ventilation requirements, and observe the operation of the equipment to check the cleaning effect.

(4) When the dust collector starts to remove dust, do not open the cleaning device first, so that the dust will accumulate on the outer surface of the filter bag slowly. After running for a period of time, open the cleaning device to facilitate the establishment of the original filter dust layer outside the filter bag. Then, iteratively tests to determine the cleaning cycle required for the device to run in the good state, and then fix the program.

3, boot sequence

(1) Power on: Turn on compressed air and air bag → start ash device → start fan → other devices in the system.

(2) Shutdown: the reverse of the boot sequence