Bag filters with capacity from 2000 m3/h

Application

Bag filters are used for dedusting of an aspirated air, formed at various processes in power engineering, metallurgy, at pouring of bulk materials, in joiner's and wood-working manufactures etc.

Bag filters, manufactured by Ltd. Aspex engineering company can be produced in special configuration, for operation with explosion/fire hazard gases and dust.

The operating temperature of a filtrated gas, steam or air should not be close to dew-point.

Description of Operation

The gas containing solid contaminant, passing through the ingate, divides into several flows and enters the output channel. Further gas reaches the bin, where large dust particles settle under the action of a gravitational force. Polluted air goes upward into the filter case to the vertically suspended filtering bags. Passing through them into the chamber of pure gas, gas is being filtrated. From the chamber of pure gas, through the ingates, gas reaches the output channel and then leaves the filter.

Passing through filtering bags, dust particles are caught on their external surfaces and form continuous dust layer which is regularly eliminated by pulsing regeneration. Regeneration is carried out by short (150 ms) pulses of a compressed air, which is fed inside the filtering elements from the holes of the blow-down pipe. Under the action of compressed air pulse on inner side tearing-off of the precipitated dust layer from an external bag surface occurs. Dust drops into the discharge hopper, then dust is removed from the filter through a lock feeder. Regeneration, namely frequency and length of a pulse, is provided by the high-perfgormance diaphragm valves which are controlled with the help of regeneration control unit through solenoid valves. The regeneration mode can be adjusted for two kinds of operation: regeneration by differential pressure and regeneration by timer. All system is carried out on the basis of Mecair components. For operation of the regeneration system the compressed air with pressure 5-8 bar without oil and mechanical impurities and also drained with a dew-point -40 °C is needed.

For the bags the filter fabric of leading world manufacturers (BWF, Keiser) is used.

Regeneration system of the filter bags produced by Ltd. Aspex engineering company.

 

Process of the filter regeneration with the help of the blow-off impulse system by compressed air:

The regeneration system OFF LINE provides more effective purification of the bag surface from the settled dust and also takes out of service separate modules for the inspection and repair without stoppage of the filter operation in a whole.

Automatic Filter Control System

The filter is supplied with an automatic control system (programmable automatic device - PLC). Given arbitrarily programmable automaton, carried out on the basis of Siemens components, allows control of all the filter modules. This system controls:

• regeneration of filtering bags;
• system of the dust emptying;
• heating of bins;
• system for preventing of the dust hanging in the bin.

Automatic control system also provides necessary blocking, informs about operation parameters and emergency states of the filter operation. System continuously represents a differential pressure at the input and output of the filter. Value of the differential pressure of the bags defines level of the cloging filter. Optimum value of a differential pressure is within the range of 1200 Pa.

On client request control system allows control of operation of the smoke exhauster, representation of the basic technological parameters of its operation.

Control of all Aspex filters is designed according to demands of the chosen technology and for the purpose of achievement of optimum economic maintenance and full automation of the equipment operation. Control units allow unproblematic commutation with control system of the highest level.

Examples Of Produced Bag Filters

Below examples of recent projects of produced bag filters with capacity from 5 000 to 10 000 m³/h, and the filter with capacity up to 85 000 m³/h are presented.

Labelling	Surface of filtration, m2	Structural pressure, Pa max/min	Specific gas load, m/min min/max	Gas consumption min/max	Number of filtering elements	Material of filtering elements	Number of modules	Overall dimensions without taking into account supporting structure (L×W×H)
Aspex 80-1-2500-i2	80	-5/-10	1/1,4	4800/6720	80	see table below	1	1585×1945×4551
Aspex 80-1-3375-i2	80	-5/-10	1/1,4	4800/6720	35	see table below	1	1900×1375×9350 (with supporting structure)
Aspex 100-1-2500-i2	100	-5/-10	1/1,4	6000/8400	100	see table below	1	1945×1945×4571
Aspex 150-1-2500-i2	150	-5/-10	1/1,4	9000/12600	150	see table below	1	1945×2820×4989
Aspex 986-2-5500-i2	986	-5/-10	1/1,4	59160/82824	364	see table below	1	6270×4030×16900 (with supporting structure)
Notes: Parameters of filter energy consumption with capacity up to 10 000 m3/h are presented without taking into account heating system of bins and systems of the dust emptying: 1000 Wt/400 V/ 50 Hz. Consumption of compressed air is determined due to dust level of aspirated air. Inlet pressure of a compressed air for regeneration system is 4-8 bar. Dew-point is -40 °C. Compressed air must not contain oil and mechanical impurities. Index i2 indicates a bag filter with dust-collecting bin and dust out-feed system on the basis of the double blinkenlights, rotary or swing valve. On demand, the filter fabric with additional surface treatment, diaphragm, microfiber impurities is possible.