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Bag filters for cast iron dust

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The Gidly catalog includes baghouse units that are directly designed for use in applications of cast iron dust extraction. We are offering 17 basic baghouse units for extraction of dust from cast iron works, graded according to the required volumetric airflow.

Cast iron dust parameters

Among the cast iron dusts in this filter group belong dusts resulted from grinding, shot blasting or working of iron castings. The cast iron dust contains a very fine fraction which tends to clog the filter bag pores. The dust separated in the baghouse is sticky, hard to regenerate and requires a larger cloth area than the usual foundry dust. The cast iron dust is abrasive, heavy and contains particles from a coarse and a very fine fraction. When on the floor, the dust is very slippery due to the graphite content.

Cast iron dust extraction

Dedusting of portable blast machines

Blast machines are used for basic cleaning of the cast iron casting from foundry sand residues. In the blasting process, both the abrasive particles from the blasting machine and some of the sand and cast iron dust get into the extraction dedusting system. Separators are therefore included in the extraction ducting to ensure that only the dust particles of the cast iron are filtered by baghouse and the abrasive recirculates in the blaster only. The blasting machine is usually pre-equipped with dust separators from the manufacturer, and the manufacturer also sets requirements for the extraction system. The extraction flow rate for cast iron blast machines should be around Q= 3000 – 10 000 m3/h per machine.

Dedusting of shot blasting chambers

Blasting chambers are used for surface treatment of large cast iron castings. Blasting is performed manually by a worker using a pressure nozzle with compressed air and the abrasives. Blasting chambers are very demanding for consuption of extraction flow rate. Air and dust extraction is done by suction grills located at the bottom of the blasting chamber, drawn through the ducting into the baghouse, and the cleaned air is then returned to the top of the blast chamber. Determination of the extraction flow rate is based on the volume of the blasting cabin – the air should be replaced 100 to 150 times per hour. The extraction flow rate therefore ranges from 10,000 to 100,000 m3 / h, according to the size of the blasting box.

Dedusting of cast iron grinding –  large spaces

The extraction is carried out in the grinding shop floor by means of concrete extraction channels. The lower extraction of the grinding workplace is carried out in a closed grinding cabin, where air is extracted downwards, then carried by ducting into the baghouse where its cleaned and then returned to the grinding cabin ceiling. The airflow direction inside the grinding cabin upwards and at speeds of approx. 0.3 m / s. The extraction flow rate should range between 800-1000 m3 / h per 1m2 floor area of the grinding cabin. With respect to the large extraction flow rate requirement of the lower extraction method, it is recommended to separate the grind area into several sections separated from the extraction line by controlable valves, thus concentrating extraction flow rate into areas where it is required the most.

Dedusting of cast iron machining

When machining the castings by milling or turning, shred pieces and dust is spreading around the tool. Extraction in this case does not serve to extract the shred pieces but to eliminate the spread of dust particles to the surrounding area. The dust extracted is very fine, sticky and, if not sufficiently extracted can cause problems with wiring because it is electrically conductive.

Baghouse parameters

Baghouse units in the GIDLY catalog are fabric filter units equipped with automatic regeneration of bags by a reverse pulse jet technology. From our experience of cast iron dust extraction applications, the lifetime of the filter media lasts for more than 20,000 hours without the need of any manual refinement. The filter media are flat smooth fabric sleeves made of non-woven fabric with an antistatic coating and an area mass of 600 grams per square meter. The filter medium does not contain folds where the dust be sedimented and is very mechanically resistant to tearing or scraping. The amount of residual dust particles ranges from 1 mg/m3 to 5 mg/m3, which allows for cleaned air to be recirculated back into the plant for heating and to save on heating costs.

Recommended ducting solution

We recommend using Group III Ducting for cast iron dust extraction – a thick-walled, welded ducting. Pipeline components such as elbows, flaps, and branches are subject to abrasion from the dust particles and material fragments. Despite the thick walls of these components, it can not be ruled out that after a certain period of time they will be damaged by abrasion.

Baghouse units for cast iron dust extraction in the GIDLY catalog

To find a specific assembly of the baghouse and fan, please go to the catalog and price list page. Select Baghouse units. From the list select „Cast iron dust extraction“. In the next step, select the required volumetric airflow of the bag filter unit. The result will be a set of items – baghouse unit+ fan +  silencer box, all of which form a dedusting system. You can then insert the items into the costing.

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