Extraction

Dust Extraction

One of the most overlooked items in the blast cleaning process is the dust extractor. Whether you need dust extraction for an automatic machine or blast room, J Reid Engineering are able to advise, design and manufacture to suit your requirements.

Environmental and health legislation means that your dust extractor must comply and perform efficiently to meet these standards. Our dust collectors will give you peace of mind that you are fulfilling these requirements.

Almost all blast cleaning operations generate dust to a greater or lesser degree. This dust must be safely removed and disposed of. The dust extractor not only removes dust from the machine but assists in keeping the surrounding area clean and dust free.

Good ducting design is critical to the correct operation of both the shotblast machine and dust extractor and should not be overlooked. J Reid Engineering use our experience and knowledge to design and recommend the correct solution for your specific application.

There are several different types of dust extractor currently available, the most common types used in shot blasting applications are mechanical shaker and reverse pulse jet cartridge type.

The volume of an extractor is determined by the size of the machine or blast room that is to be connected to.
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The purpose of an extractor is to:-

  • Provide good visibility inside the blast room.
  • Provide a safe working environment.
  • Convey the dust from the machine to the extractor.
  • Provide air washing facility for the abrasive conditioning unit.

Mechanical shaker unit

This type of dust extractor use tubular bag filters to remove any airborne dust from the blast cleaning equipment. Different types of filter material and coatings are available to suit a wide range of applications.

Dust laden air enters the extractor unit through an inlet manifold attached to a low velocity chamber. Large particles of dust drop into the lower hopper due to a change in flow direction and a reduction in velocity. The air is then drawn upwards through the filter bags where fine particles are collected. Finally clean air is drawn into the fan and then discharged to atmosphere.

The extractor unit will be equipped with a mechanical shaking mechanism to agitate the filter bags. The retained dust is removed from the filter media by this short shaking cycle where the dust cake is dislodged and falls into the bottom hopper.

The shake cycle is programmed and carried out automatically when the unit is powered down at the end of the shift or as practice dictates.

A manually operated valve discharges the dust into a suitable sealed container or bag for appropriate waste disposal.

Pulse jet cartridge unit

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The reverse jet cleaning extractor is a continuous self-cleaning cartridge unit, capable of retaining dust particles allowing passage for free airflow, whilst in operation.

Dust laden air enters the inlet side of the extractor unit and is deflected downwards. This change of direction, together with a reduction in velocity, results in a high proportion of the dust being separated from the air stream reducing the load on the filter cartridges.

In a reverse pulse jet system, a jet of compressed air is pulsed sequentially into the center of the filter cartridges expanding the pleats of the filter material and dislodges the dust cake, which has become sufficiently heavy to fall through the air stream, into the lower portion of the collector.

The control equipment also provides an over-run timer. When the fan has switched off the pulsing, cleaning of the cartridges will continue for a further “run on” period providing off line cleaning and conditioning of the cartridge filters.

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