Part 1 Performance characteristics
Plenum pulse bag type collector is a kind of de-dusting equipment with high efficiency. It combines many advantages of collectors including loculose anti-blow and pulse blow, and it has solved the disadvantages of deficiency of kinetic energy strength in loculose anti-blow and pulse blow de-dusting running in the same time, improved the applicability and de-dusting efficiency, extended life span of the bag. There’s no venturi tube in the mouth of bag or blowing tube, that reduces working resistance and makes examining and repairing easy. Electromagnetic pulse valve is of these characters: be sensitive to control, high efficiency, long life span and so on. At present, this type dust collector has been used widely.
Part 2 Basic structure and working principle
Main structures of plenum pulse bag type collector are as followers: box body and bag compartment (integrative), dust store bin, wind inlet and outlet (including screw conveyer and cinder valve), ladder, baluster, air passage system (including offline pneumatic cylinder, electromagnetic pulse valve, compressed air bag), de-dusting controller and so on.
(1) Box body
Box body is mainly used to fix cage, filter bag and air passage components, made into whole close from. Compressed air enters into box body first, and crushes inside of the filter bag while collector is de-dusting. Box body is made into 1.5 degree inclined plane, that can be prevented from seeper when used in the open air. There’s a door where someone can examine and repair on the top, installing and replacing cage, filter bag are all done here, that is very convenient. According to the difference of specification, box body is divided into some compartments separated by armor plate between them and impermeable by air, offline de-dusting will come true. There’s a lift valve in each compartment, which breaks and filtrate smoke current of air.
Bag compartment is in the below of the box body, mainly used to contain cage and filter bag and from a filtration space, cleaning of smoke is mostly done here. Like the box body, according to the difference of specification, bag compartment is divided into some compartments separated by armor plate between them and prevented from disturbing, at the same time it forms one sedimentation space.
There’s a leaked explosive hole on the wainscot of each compartment, the number of leaked explosive hole is 8.
Coal preparation equipment, there’re some coal fines produced in the process of coal preparation, but concentration of coal fine is far less than 65g/m3, so collector must not set leaked explosive holes. Even so, the filter bag should adopt antistatic filter material. You set leaked explosive hole whose area is 0.3m2 according to the structure of wainscot position. Choose the material whose thickness is equal to 1 mm L2-M anneal industrial pure aluminum plank, and the anti-pulls strength of industrial pure aluminum plank is 60Mpa, compared with the anti-pulls strength that is not less than 375Mpa of the carbon structure steel wall plank that the thickness is equal to 4 mm. The leaked explosive hole can ensure that dust collector operates in a safe condition.
（3）Dust store bin
Dust store bin is below of the bag compartment, used to store collected dust. Dust-laden gas enter into dust store bin first before into bag compartment, that the speed of gas falls and the direction of current.
（4）Wind inlet and outlet
There are two kinds of wind inlet and outlet according to the structure of the duster. The wind inlet of the 32 series is a cylinder type, and is directly welded on the lateral plate of the dust store bin. The wind outlet is in the bottom, at the side of the bag compartment, connected with inner side of the bag compartment by the plate hole of the lift valve to, other series of wind inlet and outlet are made into to a whole, put on the side of the bag compartment. The bag compartment is separated two parts from the dust store bin by a slant board, with one part as the inlet and the other outlet. Though this structure is of a big volume, the air is evenly distributed, with a good effect, and suitable for occasions where dust-laden gas is of a great concentration.
2 Working principle of plenum pulse bag type collector
When dust-laden gas enters the dust store bin from the inlet, some heavier dust drops into the dust store bin as a result of habitual collision and free settling, large amount of dust follow the rising air current and enter into the inside of bag compartment. Dust is detained outside the filter bag after being filtered by filter bags, and the purified gas goes into the bag compartment from inside the filter bag, then discharged into the air through the hole of the valve board and the outlet. As it goes on and on, the dust detained outside the filter bag increases, so it causes operating resistance of dust collector rising. If the resistance rises to the pre-set number(1245－1470Pa), the controller will send out signals, first to control the lift valve to do these operations: close the hole of the valve board to cut air current and stop filtering, and then to open the electromagnetic pulse valve to blow compressed air whose pressure is 0.5-0.7Mpa into filter bag with a short time(0.01－0.12s). The compressed air immediately expands and swarms into filter bag, that make the bag to distort and vibrate, adding the effect of adverse air current, the dust detained outside of filter bag is dropped into the dust store bin. After the de-dusting is finished, lift valve open again, and dust collector begin filtering once more.
Plenum pulse bag type collector is made up of several compartments, where de-dusting is in order, and this is compartment-by-compartment off-line de-dusting. Its advantages are that the de-dusting compartment and the filtering compartment do not interfere each other, help realizing long-term consecutive operating and improve de-dusting effect.