Analysis the five parts of the bag filter wear

The bag type dust collector is generally composed of an auxiliary system such as a main machine, a filter element (dust bag), and a back blow control. The dust bag is the core component of the bag filter. Its material, sewing, use and maintenance are related to the efficient and stable operation of the whole system. The air volume, dust concentration, load balance, flue gas temperature and humidity, and corrosiveness of the dust removal system. Such factors may cause damage to the dust bag. Wear is a common type in many types of dust bag damage and is closely related to the design, manufacture and application of the dust collector.

The category of damage and loss of dust bag and its cause

The common dust-removing bag has the main effects of wear, burning and corrosion.

Filter bag wear refers to the use of repeated filtering and backflushing during the use of the dust bag. The bag bulges and contracts, the relative movement between the bag and the dust-removing frame or other components, and the high-speed dust-containing airflow scouring causes local wear.

The dust bag is burnt due to the abnormally high temperature of the treated flue gas or the high temperature dust particles, and the temperature is higher than the withstand temperature of the filter material, so that the filter material in the high temperature portion is damaged and damaged.

Corrosion of the filter bag is caused by the harmful reaction of the flue gas, causing the chemical reaction of the filter material, resulting in a decrease in the mechanical properties of the filter material and a loss of efficiency. The corrosion of the filter bag occurs in the condition that the smoke component exceeds the standard condition, and can be divided into gas corrosion and liquid corrosion. The harmful gas component is more likely to cause damage to the filter bag in the presence of liquid.

Due to the presence of liquid components (such as condensation) in the flue gas, a paste-like substance is formed with the dust, which blocks the gap of the filter bag, causing the paste bag to cause dust removal failure.

Prevention and treatment of dust bag wear

Dust bag wear is the main type of bag loss. After other broken types cause broken holes, the dusty airflow washes further wear. Wear is closely related to the structural design of the bag filter, air flow organization, backflushing and so on. The occurrence of wear of the dust filter bag is divided into the following five cases: filter bag mouth, filter bag body, filter bag lower, filter bag bottom and filter bag inside, the wear and tear of different parts and their factors are different, the solution It is also different.

Wear of the dust bag pocket

The wear of the bag mouth is mostly within 400mm of the bag mouth, and the damage marks are mostly from the inside to the outside. This type of wear is mainly caused by the pulsed backflushing compressed air deviating from the center of the filter bag and directly scouring the side wall of the filter bag. When the compressed air deviating from one side is continuously flushed, the inner side layer of the filter bag is first blown off by the compressed air, then the base fabric is blown off, and finally the filter surface is blown. When the filter bag is damaged on one side, the resistance at the breakage is reduced, and the dusty fumes will quickly enter from the breakage, scouring the damaged corners, forming new voids and new dusty flue gas inlets, and increasing voids eventually result in bags. The mouth is broken, and in severe cases the bag head and the bag body are separated. Such damage is mainly caused by excessive compressed air pressure, skewing of the short pipe, deformation of the flower plate, etc. Once such wear is found, the blowback spray should be applied before the new bag is replaced.

Filter bag body wear

The wear of the dust bag body, the vertical strip wear marks in the middle of the filter bag, in several cases:

If the damage marks are from the inside to the outside, the damage is in the contact of the vertical ribs of the bag cage, which means that the vertical ribs of the bag cage are desoldered or rusted, the filter bag is worn out or the pressure is too high, and the spray is too frequent, so that the filter bag and the bag cage The contact position is broken and broken to cause breakage. This type of wear can be addressed by changing the bag cage or adjusting the blower.

If the damage marks are from the outside to the inside, break the contact at the vertical ribs of the bag cage. It is often seen that the outside of the filter bag (adjacent filter bag or box member) has traces of rubbing against the filter bag. This kind of wear is the deformation of the bag cage or the installation of the filter bag is too small, the diameter of the filter bag is too large or slack, causing contact between the filter bag and the filter bag, the filter bag and the dust collector case member, and the filter bag is in the back blowing process. The expansion rubs against each other and causes it to wear. It is generally necessary to replace the bag cage and ensure the quality of the installation. During the design of the bag filter, the distance between the filter bag and the distance between the filter bag and the box structure should be kept too small.

Dust bag bottom wear

The mechanical wear of the lower part of the filter bag: the outer side of the filter bag is more than 300mm in the bottom of the filter bag. The wear is mostly on one side, the lower part is the most serious, and the upward direction is gradually reduced. The partial sewing thread will be worn off, and the sewing thread will be strong in the position where it is not worn. Such wear is caused by deformation of the flower plate, too small hole spacing, deformation of the bag cage, and excessively long filter bags. Individual filter bags and dust collector walls are damaged by friction. Such damage is strictly checked for the level of the panels and a well-made bag cage should be used.

Annular wear in the lower part of the filter bag: an annular wear cavity is formed from the outside to the inside of the filter bag. This kind of wear is caused by the partial flushing of the filter bag by the dusty flue gas, indicating that the airflow velocity in the filter bag is too large. It is more common in dust collectors with higher filtration wind speed or dust with stronger abrasiveness. When the filter bag is damaged on one side, the dust will be washed and damaged diagonally. The damage will expand continuously with time, and the damage of the filter bag will cause the filter bag to ring. .

The inside of the lower part of the filter bag is worn: it is more common in the position of contact with the bag cage. Most of the difference between the diameter of the bag cage and the bottom of the bag cage is too large, resulting in excessive change of the filter bag during cleaning and filtration, and the bag cage is damaged by friction. Replacing the premium bag cage will solve it.

Filter bag bottom wear

Wear on the outside of the bottom of the filter bag: There are obvious signs of wear on the damaged surface. The bottom sewing thread and the filter base fabric are worn off, and the bottom of the bag is broken or the whole is peeled off in severe cases. This kind of wear is caused by the high level of material in the hopper, and the airflow raises the dust particles directly to wash the bottom of the bag, causing wear. By increasing the ash discharge capacity of the ash bucket and adjusting the ash discharge operation system of the ash hopper, the dust accumulation is prevented from being too high, and the eddy current wear filter bag can be avoided in the ash hopper.

The inner side of the bottom of the filter bag is more likely to be worn at the bottom of the bag cage or the filter bag is too long, and the bag cage can only support the bottom of the bag. When the filter bag is cleaned and switched during filtration, the bottom of the filter bag is shaken, resulting in wear on the bottom side of the filter bag.

Wear inside the dust bag

The inside of the filter bag is mostly damaged. The difference between the outer diameter of the bag cage and the inner diameter of the filter bag is too large, causing the swinging range of the filter bag to be cleaned and filtered when the filter bag is too large. The inside of the filter bag and the bag cage are rubbed, causing the inside of the filter bag to wear.

The inside of the filter bag is damaged at the bag cage, and there are rust marks on the wear. Most of the bag cage is corroded and the surface is formed with an angular oxide layer. At this time, the surface of the bag cage is like sandpaper. Once it is cleaned, the filter bag will be seriously rubbed once. Finally wear the filter bag. Use a high quality bag cage that matches the filter bag to avoid wear on the inside of the filter bag.

The dust bag is the heart of the entire dust collector, and the failure of the filter bag will make the whole device unable to operate normally. The wear of the filter bag is mainly related to the design and application, manufacturing and installation quality of the dust collector. The wear process begins locally, but as long as small wear holes are formed, it will spread quickly, causing greater damage to the filter bag. Therefore, it is also an important factor to avoid the large-scale filter bag wear, because the inspection, inspection and early detection of small wear during the operation are strengthened.