How do you use a filter bag

Since SFFILTECH was founded in 2006, after nearly ten years of hard work and accumulation, SFFILTECH’s products have become well-known in the industry, and the company’s brand has also been branded with quality filter bag products and service providers. It is one of the major professional manufacturers of dust removal filter bags in China, and is also the manufacturer of micron level liquid filter bags with considerable scale in China.

Pulse filter bag filters are used in most industries, including projects under construction. Pulse bag filter has many advantages, small size; High filtration wind speed; Small floor area; Easy to maintain.

However, most customers do not understand or even know nothing about the use of dust removal equipment and filter bags. In order to enable customers to prevent problems and solve corresponding problems in use, the use problems and treatment methods of pulse ash cleaning filter bags are now sorted out and provided to users.

According to the problems in the application of filter bags and the treatment methods, the following are listed in detail:

1、Filter bag wear

1. Filter bag mouth

(1) The damage at the opening of the filter bag is mostly within 400 from the opening down, and the damage trace is mostly from the inside to the outside. The surface layer is first blown off by compressed air, then the base cloth is blown out, and finally the filter surface is blown out. When one side of the filter bag is damaged, the flue gas usually passes through the position with the least resistance. The flue gas directly passes through the air purification chamber from the damaged part. When the flue gas passes through, the dust will wash the diagonal corner of the damaged part, resulting in the annular damage of the bag mouth, and even the separation of the bag head and the bag body.

The damage is caused by the high compressed air, the slanting of the blowing pipe, the deformation of the flower board, etc. The damage can be avoided after adjustment.

(2) The bag mouth is damaged in the groove, and the damage marks are mostly from the outside to the inside. The groove is worn off, and the bag head falls off in serious cases.

The damage is caused by improper installation or small pocket opening diameter.

(3) The outer side of the bag mouth is damaged within the length of the blowing pipe and the flower board, and the damage marks are from the outside to the inside. The fiber and the base cloth are worn or broken, or even fall off.

The reasons for the damage are mostly poor installation, small bag mouth or high differential pressure, which causes the filter bag to break away from the perforated plate and top on the blowing pipe or the cover plate of the dust collector, resulting in the final friction damage. It is often seen in the dust removal of blast furnace gas.

2. Position of filter bag body

(1) There is strip wear on the outside of the filter bag

① If the damage marks are on the vertical reinforcement of the bag cage from the inside to the outside, it means that the vertical reinforcement of the bag cage is desoldered or rusted, and the filter bag is broken, or the spray pressure is too high, and the spray is too frequent, so that the contact position between the filter bag and the bag cage is folded and broken. The problem can be solved by replacing the bag cage or adjusting the injection device.

② If the damage trace is from the outside to the inside, and the damage is on the vertical bar of the bag cage, it means that the deformation of the bag cage causes the friction between the filter bag and the filter bag, and the damage can be avoided by replacing the bag cage.

(2) The filtering surface of the liquid filter bag body has progressive wear, which occurs mostly at the lower part of the support ring of the bag cage, but rarely at the upper part. This kind of damage is caused by smoke and dust scouring, and the problem is caused by uneven air flow distribution and high filtering wind speed.

3. The lower part of the filter bag is damaged

(1) The damage on the outer side of the lower part of the filter bag is mostly seen within 300 mm from the bottom of the filter bag upward, and the damage is mostly on one side. The lower part is the most serious, and gradually reduces upward. The local sewing thread will be broken, and the strength of the sewing thread is good at the position where there is no wear. This kind of damage is mainly caused by the deformation of perforated plates, the spacing of perforated plates is too close, the deformation of bag cage, the long filter bag and other reasons. Some filter bags and dust collector walls are abraded and damaged. For such damage, the levelness of the perforated plate shall be strictly checked, and the error shall be less than one square meter (<1/1000), and the bag cage shall be well made.

(2) The annular damage of the lower part of the filter bag is mostly seen in the dust remover with high filtering wind speed or the dust with strong abradability. When one side of the filter bag is damaged, the smoke washes the damaged diagonal, and the damage continues to expand with time. The serious damage of the filter bag can lead to the annular fracture of the filter bag.

(3) The inner side of the lower part of the filter bag is mostly worn at the contact position with the bag cage, most of which are caused by the large difference between the diameter of the bag cage and the bottom of the bag cage, resulting in the excessive change of the filter bag during ash cleaning and filtering, and the friction and damage of the bag cage. It can be solved by replacing the high-quality bag cage.

4. The bottom of the filter bag is damaged

(1) The bottom of the filter bag is mostly damaged on the outside, and there are obvious wear marks on the damaged surface. The bottom sewing thread is worn off, and the filter base cloth is worn off. In serious cases, the bottom of the bag is damaged or the whole bag falls off. Adjust the dust discharge work of the dust hopper of the dust remover to avoid excessive dust accumulation and eddy current abrasion of the filter bag.

(2) The internal wear of the bottom of the filter bag is mostly seen in the case that the bottom of the bag cage is too small or the filter bag is too long, and the bag cage can only support the part of the bottom of the bag. The inner side of the filter bag bottom is worn due to excessive action during dust removal and filtration.

(1) The inner side of the filter bag is mostly damaged because the difference between the outer diameter of the bag cage and the inner diameter of the filter bag is too large, resulting in the wear of the inner side of the filter bag due to the excessive action of the filter bag during ash cleaning and filtering.

(2) The damaged position of the inside of the filter bag is at the bag cage, and there are rust marks at the worn part. Most of them are the oxidation layer with edges and corners formed on the surface of the bag cage after corrosion. At this time, the surface of the bag cage is similar to that of sandpaper, and the filter bag will be severely abraded once every time the ash is cleaned, and finally the filter bag will be worn. Replace the high-quality bag cage.

In general, the following principles should be maintained when using filter bags

1. The filter bag is not suitable for hanging too loose or too tight. Too loose is very easy to accumulate dust, and too tight is very easy to wear.

2. The old dust removal cloth bag of new process and new process cannot be mixed to prevent damage to the normal operation of the machine and equipment.

3. Remove and replace the filter bag, first blow it with air compression, and then check whether there is any rotten hole, and leave it to be removed and replaced after repair. For example, the dust removal bag stained by smoke and dust shall be cleaned with tap water and left to be replaced after cooling.

4. Blockage of filter bag. When the filter bag is blocked, the friction resistance will increase, which can be mainly reflected by the expansion of the reading value of the differential pressure gauge. The clogging of filter bag is the key reason for the damage, perforation and falling of dust removal bag.