The performance of hydraulic filter element determines the height of the product

By Marrie December 24th, 2018 50 views

Hydraulic filter element is one of the important equipment of ventilation and dust removal system.The stand or fall of dust remover job will affect the environmental sanitation of workshop, factory area directly, even residential area.Master the classification and working principle of dust remover can be a better choice and use of dust remover!

Filter type dust collector

There are many forms and types of bag-type dust remover. According to the way of ash removal, it can be divided into three categories: mechanical ash removal, reverse flow ash removal and pulse jet ash removal.According to the filtering mode, it can be divided into inner filtering mode and outer filtering mode.According to the different positions of the inlet and outlet, it can be divided into two categories: lower inlet air and upper inlet air.
Bag dust collector
The reverse air flow ash removal is to use the form of outdoor or circulating air and the opposite direction of the dusty air flow filtration bag, so that the dust layer on it falls off and falls into the dust bucket.In this way, on the one hand, the viscous stripping force formed by the dust layer in the opposite direction of the dust removal airflow can directly strip the dust layer.On the other hand, due to the change of air flow direction, the filter bag produces expansion and contraction vibration, which is also conducive to the fall off of dust blocks.

Pulse jet ash removal mode
After the compressed air is ejected through the nozzle at a high speed, the surrounding air is induced to be injected into the filter bag in a very short time, which causes rapid expansion and contraction of the filter bag.On the one hand, the dust layer is removed by means of the stripping force of the jet air flow on the dust layer; on the other hand, the dust layer is discarded by the reverse acceleration formed in the retraction process of the expansion filter bag.The ash removal intensity of this method is large, which can be carried out under the condition of filtration, and the allowable filtration wind speed is also high.Because of the advantages of pulsed jet ash removal, it has gradually become a main dust removal method of bag dust collector.

Filter bag corrosion
Corrosion is one of the most common causes of filter bag damage, because the smoke contains a variety of corrosive substances, and corrosion in the high temperature environment is greater, which will cause damage to the filter bag.The main causes of corrosion are hydrolysis, oxidation, acid and alkali corrosion.Among them, hydrolysis and oxidation cause more damage, while acid corrosion is less, alkali corrosion is less.
(1) acid and alkali corrosion
The main reason for corrosion is that the smoke contains acid and alkaline components, and the dew point changes with the concentration of the gas of these chemical substances. If the dust collector is started up or stopped below the dew point, the SO2 in the waste gas will meet water and form H2SO4, which will cause the fiber of the filter bag to harden, deform and lose strength and damage.
Corrosion damage marks are mostly radial, and a large area of discoloration is formed on the surface of the filter bag, resulting in a hard and brittle filter bag and a small number of irregular circular holes.FIG. 8 shows that the HCl content in the flue gas in the chlorination section of a magnesium oxide plant in henan is very high. The average service life of PTFE filter bag is less than 3 months, and it is corroded so that it cannot be used any longer.Therefore, if the filter bag is cleaned by pulse under this condition, the damage of the filter bag will be accelerated.

In addition to acid, alkali corrosion, corrosion of organic solvents on the filter bag also nots allow to ignore, such as waste incineration exhaust gas in some of the micro content material damage to the filter bag, it is unable to make a reasonable explanation to its, because these substances content is too low, low to even cannot be detected, but they are actually consist in tail gas, the harm is great.Bromine vapor (Br2), for example, although extremely small in content, can cause fatal damage to the filter bag.
(2) hydrolysis
Fiber hydrolysis is a process in which water molecules enter the fiber and react with the polymer to break the molecular chain and form new small molecules.The fiber is damaged due to its reduced molecular weight and reduced tensile strength.Synthetic fibers made from polycondensation polymers are resistant to hydrolysis.For example, common polyester, nomex and other filter materials are easy to hydrolyze.
Only under the combined action of high temperature, humidity and chemicals can molecules be activated and hydrolyzed.The higher the content and temperature of water molecules in flue gas, the more serious the hydrolysis of filter bag.The hydrolysis temperature of different filter materials is also different.P84 is one of the filter bags with poor hydrolysis resistance.
The hydrolysis trace is the color turbidity, the filter bag strength drops seriously, is easy to damage.After hydrolysis of the sewing thread, the filter bag cracks from the sewing thread, so that the filter bag is no longer cylindrical.The sewing thread of the filter bag is broken.
(3) oxidation
The molecules of a fiber oxidation is lost (or dissociation) electronic process, such as PPS fiber, under the condition of high temperature (150 ℃) oxygen attack points of child "S", and combine with them.PPS fiber changes color, hardens and becomes brittle, and the strength decreases and damages. In case of serious damage, the fiber network will break away from the base cloth (as shown in FIG. 10).Oxidation is another major factor of filter bag damage.The filtration materials with poor oxidation resistance mainly include: polypropylene, polyphenyl sulfide (PPS), etc.

Mechanical ash removal
This way of ash removal can include manual vibration, mechanical vibration, etc., is one of the simplest ways of ash removal.Generally speaking, the vibration distribution of the filter bag along the axial direction of mechanical vibration is not uniform, and the acceleration attenuation is fast, the filter bag length is generally short, and the filter wind speed is small.Mechanical vibration dust bag filter adopts mechanical motion device to make the filter bag vibrate periodically so that the dust particles attached to the filter bag fall into the dust bucket.According to the different vibration modes, it can be divided into three forms: horizontal vibration, vertical vibration and twisted vibration.
(a) is the horizontal vibration, which can be divided into top vibration and middle vibration;

(b) for vertical vibration, it USES the eccentric wheel device to vibrate the filter bag frame or periodically lift the filter bag frame for ash removal;

(c) is torsional vibration, which USES the mechanical transmission device to twist the filter bag at a certain Angle regularly to make the dust particles fall off.

Inside and outside the nternal filter type is generally applicable to mechanical dust removal and reverse flow dust removal bag dust collector.The dusty air flow of the external filter filter is included into the filter bag through the filter material from the outside of the bag, and then it is cleaned and discharged.To facilitate filtration, a supporting framework (bag cage) shall be set inside the filter bag.The external filter type is suitable for pulse jet bag type dust collector, high pressure air flofilter type
The dust-containing airflow of an internal-filter filter first enters the inside of the filter bag and is filtered from the inside out. The dust is deposited on the surface of the filter bag.The outer side of the inner filter bag is the clean gas side for easy inspection and bag change.The iw back bag type dust collector, flat bag type dust collector, etc.

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