PPC type air box type pulse bag duster

I. Overview

 PPC gas box pulse bag filter is a new type of gas box pulse high-efficiency pulse bag filter. It synthesizes the advantages of various types of bag dust collectors, overcomes the disadvantages of poor strength of chamber blowing, pulse blowing and filtration at the same time, and expands the scope of application. The product has the characteristics of overall ash cleaning in the chamber and adopts the form of large-size electromagnetic pulse valve ash cleaning, which has the characteristics of strong ash cleaning ability, good effect and long service life. The product is suitable for the management of high concentration dust, can simplify the dust management process, reduce equipment investment. Product structure is compact, covers an area of less, can reduce the construction investment. It has significant environmental benefits, social benefits and economic benefits, and fills the domestic blank of gas-vibration pulse ash cleaning, with domestic leading level.

 PPC air box pulse bag filter has four series and 33 kinds of specifications. Filter area from 93-4361m2, handling air volume from 6900m3/h to 314000m3/h, widely used in building materials, cement, metallurgy, machinery, chemical and refractory industries; especially for cement plant crushing, packaging, top of the reservoir, clinker cooler and various mills and other dust collection system (or dust removal system); can also be applied to coal mill dust collection, but to add anti-flammable and explosion-proof measures, the dust collector structure should be changed accordingly. The structure of dust collector should be changed accordingly. It can also be applied to dust collection of gas with particularly high concentration of dust, such as the milling system with o-sepa powder selector, the concentration of dust in the gas is up to 1000g/m3 (standard) or more, and may not be set up as a pre-collection of dust with the cyclone dust collector. For the cold area in the north of China, this dust collector can be applied after adding heating and heat preservation device.

II, the structure and working principle

 1、Structure

 This is a kind of bag filter which is assembled by chamber structure, and the electromagnetic pulse valve at the top of the chamber takes turns to clean the filter bags in each chamber by stopping the air box pulse (the so-called off-line cleaning). It is different with the general blowing pulse bag filter cleaning, blowing pulse cleaning is in the same filter room only on which the rows of filter bags row by row for blowing cleaning (so-called online cleaning), while other rows of bags are still filtering, that is, cleaning and filtration at the same time in a room mixed, clean down the dust secondary flying, some of them will be collected by the neighboring dust filter bags, is not conducive to the filtering of gases containing large concentrations of dust. PPC type split chamber air box pulse is carried out in a room to stop filtering under the situation of shutting down the valve, and does not stop to replace the filter bag of a room.

 This dust collector is divided into four series of A, B, C and D according to the number of different bags, and each series is divided into various specifications according to the number of different chambers, totaling 33 types.

 Its structure is shown in the attached selection chart, which is composed of the following parts.

 (1) shell part: including clean room (or gas purification box, gas box), filter room, chamber partition, access door and shell structure. The cleaning room is equipped with a lifting valve and a flower plate, a short pipe for blowing, and a filter bag and its skeleton in the filtering room.

 (2) Ash hopper and unloading mechanism: there are ash hopper and according to different series, different import dust concentration, respectively, set up the screw conveyor, air conveying chute and rigid impeller feeder (i.e., unloading valve).

 (3) Inlet and outlet air box: including inlet and outlet air piping and center partition. Single-row (or single-row) structure is arranged on one side of the shell, double-row (or double-row) structure is arranged in the middle of the shell. a series of smaller no box, inlet and outlet air piping were connected to the ash hopper and clean room.

 (4) Pulse cleaning device: including pulse valve, air bag, lifting valve cylinder and its solenoid valve.

 (5) Compressed air pipeline and its decompression device, oil-water separator, oil mist, etc.

 (6) Pillar and vertical cage ladder, railing.

 2、Working principle

 Dust-containing gas from the dust collector inlet and outlet box body (A series from the dust hopper into) into the sloping partition turned to the dust hopper, while the gas flow slows down, due to inertia, the coarse dust in the gas falls into the dust hopper, fine dust particles with the gas flow folded upward into the filtering chamber, dust attached to the dust bag appearance, the purified gas through the filtering bag into the upper cleaning room, cleaned by the various chambers converged through the outlet by the main fan of the dust removal system sucked out of the dust system, and the dust is removed. The main fan of the dust removal system is sucked out and discharged into the atmosphere.

 With the continuous filtration conditions, the dust attached to the exterior of the filter bag gradually increased, the resistance of the gas flow through the gradual increase. When it reaches a certain resistance value (for example, 1990Pa), according to the need to manually, but also through the fixed pressure or timed cleaning pulse controller, automatic control to start the dust collector chamber of the lifting valve is closed, cut off the airflow through the filter room, and then open the electromagnetic pulse valve release of high-pressure compressed air, all the bags in the air box of the chamber of the pulse blowing cleaning (stopping the air to clean up the dust), so that each filter bag is suddenly bulging, thus vibrating down the bag surface. The filter bag suddenly swells, thus vibrating down the dust attached to the bag surface, restoring the pressure difference between inside and outside the bag to the starting state, and the dust sinks down to the dust hopper. Afterwards, the program controller opens the lifting valve according to the specified interval to restore the filtration of the chamber, and then starts the lifting valve of the second chamber, closes and cuts off the filtration airflow of the second chamber, opens the solenoid valve of the second chamber to release the high-pressure compressed air, and carries out the air-stopping pulse blowing and cleaning of all the bags in the air box of the second chamber to clear the dust on the second chamber's filter bags. After that, the program controller opens the lifting valve of the second sub-chamber to restore the filtration of the second sub-chamber. After that, according to the pre-specified electronic control program for the third chamber, the fourth chamber ...... of the filter bag to stop the air blowing dust, until the latter chamber is cleaned up, turn off the electronic control device, dust collector to restore all the formal filtration dust collection.

 The time of stopping and blowing the filter bag, the interval time between chambers, and the cleaning cycle are controlled by the program control printing, and each time is adjustable, see the electric control manual.

 This dust collector generally works under negative pressure, but it can also work under positive pressure without changing the structure.

III. Selection instructions

 Selection instructions:

 1, the selection of filtering wind speed:

 Filtering wind speed refers to the wind speed through the filter bag filter media (m/min). Some called air cloth ratio, refers to the unit time, the unit area of the filter media through the amount of air m3/min/m2, that is, m/min. Filtering air speed selected according to the filter media dust and flue gas characteristics, temperature and humidity, dust concentration, dust removal and the nature of the selected filter media and decision. Filtering air velocity not only determines the size of the dust collector, but also has a great influence on the resistance of the filter media, dust removal efficiency and dust removal effect. In order to ensure the dust removal effect, improve the life of the filter bag, reduce the resistance, the dust collector filtration wind speed is generally used 1.2m/min, the filter wind speed of the main dust source points in the cement plant in the use of the conditions of the dust collector, the net filtration wind speed is recommended to be used in accordance with the Table 1.

 Net filtration wind speed refers to the filtration wind speed m/min under the filtration area of other chambers when one of the chambers of the dust collector is stopped for dust removal and the original air volume passes through the other chambers.

 2, the calculation of the filter area, according to the following formula:

 AN=Q/60×VN, m2

 Where: AN - net filtration area m2, refers to a dust collector in one of the room stops the wind blowing back, the rest of the various chambers of the sum of the filtration area.

 Q - through the dust collector filtration air volume, also known as the amount of gas m3/h.

 VN - net filtration wind speed m/min.

 3, Operating temperature and selection of filter media

 Operation temperature is closely related to the selection of filter media. Different filter media, the permissible inlet temperature of dusty gas is also different. The dust collector generally uses polyester needle felt, allowing continuous use of temperature ≤ 120 ℃. When aramid needle felt is used, the permissible operating temperature can reach 200℃. When polypropylene needle felt is used, the permissible operating temperature is 90℃. When exceeding the permissible temperature of each filter material, the gas should take cooling measures between entering the dust collector.

 4, Allowable inlet concentration

 Due to the special structure of this dust collector, it adopts stop-air pulse blowing cleaning (off-line cleaning), so its permissible inlet concentration is higher than that of the traditional pulse blowing cleaning (online cleaning) and other dust collectors with general compartmentalized reverse blowing cleaning. The permissible inlet gas dust concentration of this dust collector is 200 g/m3 (standard) for the A series (small), and up to 1000 g/m3 (standard) for the other B, C and D series. The dust concentration of the dust collector outlet gas is <100mg/m3(standard).

 5, Dust removal control mode

 The dust collector cleaning control generally adopts timing mode, according to the use of the plant's actual bag resistance rose to a certain value (generally 1990Pa) of time (averaged over time), the signal generated by the time relay, through the program of electronic control instrument on the control of dust cleaning. Can also be used in a fixed-pressure mode, according to the bag resistance rises to a certain value (~ 1990Pa) of the pressure, the signal generated by the differential pressure transmitter, through the pulse controller on the control of the ash cleaning, room by room ash cleaning. It can also be controlled manually and selected by users.

 6, Examples of dust collector selection

 A F3.5×12m cement mill, the ventilation of the mill is 30000m3/h, the gas temperature is 110℃, the gas dust concentration is 150g/m3 (standard), try to choose a dust collector.

 Selection: (1) According to the characteristics of the cement mill, look up Table I, know that the net filtering air velocity applied to the cement mill is VN = 1.5m/min.

 (2) According to the given ventilation volume and net filtration wind speed calculation, its required net filtration area.

 AN=Q/60VN, m2=30000/(60*1.5)=333 m2

 (3) According to the 333 m2 net filtration area required to check the dust removal equipment performance table, select the approximate need for dust collector. Check table two, approximate PPC7B-450 type, AN = 372 m2; PPC5C-460 type, AN = 372 m2.

 Two specifications are optional, which is more appropriate, according to the actual situation of the user to decide specifically. Such as the use of large sites, you can choose to use 5 compartments of the PPC5C-460 type, the weight is also light. If the site is long in length and narrow in width, LPM7B-450 can be chosen.

Ⅳ Installation requirements

 1、The installation of dust catcher should be carried out according to the design drawings and relevant installation specifications.

 2, dust collector flange connectors (including compressed air piping) should be cleaned, embedded in the screw holes on the inside and outside of the gasket, and then on the bolts to tighten (screw holes on the inside of the gasket must be), in order to prevent air leakage.

 3, each check door, hole sealing gasket must be bonded tightly with glue, lap joints are not allowed to leave gaps, and must be diagonal joints, shall not fall off.

 4, the handling and parking of the filter bag should pay special attention to prevent the bag and the surrounding hard objects, sharp objects in contact, collision, prohibit feet, heavy pressure, in order to prevent damage.

 5, the filter bag should be installed tightly to the flower plate orifice, not to leave a hole to prevent dislodgement and air leakage.

 6, before installation, should check the shell in and out of the air duct, filter room, clean room in the welds are not de-welded. When installing and welding the parts for disassembled transportation, special attention should be paid to the sealing of the above chambers and air ducts to prevent air leakage.

 7, the transmission parts should be installed correctly, rotate flexibly, and add lubricating oil.

 8、If the dust catcher is installed in the outdoor open air, the rainproof canopy should be built on the top.

V. Maintenance management requirements

 1、Develop the maintenance management duty system, duty personnel to record the operation. Frequently check whether the electronically controlled ash-cleaning device (including program-control instrument, solenoid valve, pulse valve, lifting valve, etc.) operates normally, and adjust the time of ash-cleaning when necessary to ensure the efficiency of ash-cleaning.

 2、Regularly check whether the compressed air system is running normally and whether the pressure of air source meets the requirements and is stable. The water filter should be drained frequently, and the oil mist should be refueled regularly.

 3、Regularly check the action of the cylinder and the sealing of the lift valve, if the cylinder is found to be leaking or the valve seat gasket is bad, it should be overhauled and replaced in time.

 4, at any time to monitor the emission of soot concentration, such as the discovery of ash, should promptly check the filter bag breakage and filter chamber sealing, plug the air leakage porosity, replenish the bag or replace the new bag.

 5, rigid impeller feeder (ash discharge valve), screw conveyor and other ash removal devices should be run at the same time with the dust collector, dust collector is out of service, should be emptied of ash in the dust hopper, in order to prevent the dust from drying out when not in use.

 6, before the dust collector is shut down, the filter bag should be cleaned manually, so as not to accumulate too much dust on the bag, and then it is not easy to clean the dust when it is used.