Dust extraction: cyclones and filters

We like to apply our experience to the specific challenges involved in different industries. Consider:

Correct choice of filter cartridges for the dust, guaranteeing correct cleaning;
Correct sizing of a dust collector based on the size of the area to be extracted;
Pre-separators such as a cyclone or other type, properly sized based on particle size and flow rate;
The right fan that can provide the right negative pressure to move air and dust through the system at the right speed.

Cyclones and filters for the powder coating industry

Among other things, Naaykens’ filters are used for the extraction of powder coating booths. Powder coating is a popular way to provide products with a stable and strong coating, where good extraction is important to ensure visibility in the booth.

In powder coating, powdered paint is sprayed around the products. However, not all of this powder paint adheres to the product, known as overspray. The advantage of working with dry powder paint is that it is also recyclable, which can be a budget-friendly and environmentally responsible choice for powder coaters.

Design of an industrial dust collector for powder coating
Powder coating is collected in oil drums for easy collection and transport of large amounts of dust.

Dust extraction for an expansion powder coating plant

A powder coating company wanted to expand its powder coating capacity, so Naaykens Luchttechniek was asked to provide dust extraction. The wish was for a total solution with piping from the cabin, to filter and cyclone.

For this dust extraction, Naaykens has the knowledge and production in-house to tune the installation exactly to the particle size and to the dust. After all, the air speed in such extraction installations is very important. If the speed is too low, dust will accumulate in undesirable places, or will not settle sufficiently in the cyclone. Via this cyclone, up to 97% of the extracted powder coating (the “overspray”) can easily be recovered. Improper sizing will result in wastage of valuable powder. Of course, excessive speed will also cause unnecessary additional energy consumption.

1: Schematic structure of a powder coating plant dust collector.

Appropriate solution with dust extraction next to the powder coating booth

As frequently happens, the intended location of the filter installation at this powder coater was in an existing location. Again, we used our expertise to make the best use of the available space, and to be able to direct the air flow in the right direction.

Technical Characteristics

Reference	Order 84403
Flow rate (m3/h)	20.000
Specific requirements	Powder coater, limited space, powder coating recovery via cyclone
Filter size (LxWxH)	6200 x 2300 x 2200 mm
Fabric Type	Epoxy powder coating
Density	1.6 g/cm3
Particle size	10-60 μm

Supplied filter systems for powder coaters

The pictures below show examples of different dust extraction systems. Here you can also see that we often install our filters outside – this saves space and has the advantage that the removal of the collected dust can take place outside.

Impression of supplied dust extractors

In the pictures below you can see an impression of two of our supplied dust extractors. These filters are equipped with silencers for quieter operation. Also shown here are two different collection methods; 200L oil drums and big-bag bags. Both are ideal for easy disposal of large amounts of dust.

Klik om te vergroten

Are you also looking for a dust collector for your powder coating installation?
We are happy to take a look and can offer you customized, no-obligation advice.

Dimensioning of cyclone based on dust type

Sizing a cyclone correctly can be a difficult challenge, but one that Naaykens has extensive experience with. Dust collection in a cyclone is never perfect, but with the right choices it is possible to capture up to more than 97% of the dust.

The graph shows how this separation is distributed for a given cyclone: finer dust will not be separated as well as coarse dust.

It is essential to know what the dust is before determining which cyclone is right for the process.

Because of this mechanism, a cyclone will never be able to separate 100% of the dust, especially the smallest fraction. For the separation of most of the dust, a cyclone is a very good solutions, where the combination with a cartridge filter or only a post filter ensures that the finer fractions are also separated.

A number of formulas are important for sizing. These formulas are used how well particles of certain sizes are separated (see graph above), and what the pressure drop across the cyclone is. For performance is on influence:

The diameter of the cyclone;
The flow rate through the cyclone;
Fabric density;
The viscosity (and temperature) of the air.

A smaller cyclone will provide good separation. However, this also creates a higher pressure drop across the cyclone, which means a more powerful fan may be needed.

Another option is to use multiple cyclones – such multi-cyclones were used very often in the past.

A useful comparison is a car flying out of the curve: where the dust particle is the car and flying out of the curve means that the particle hits the edge of the cyclone; and is thereby separated. Flying out of the curve is easier with high speed, a larger car, as well as when the curve is tighter.

Cyclones supplied by Naaykens Luchttechniek

In the pictures below, you can see a few cyclones that we have supplied in previous projects. Here you can also see how we use these cyclones as pre-separators: where the cyclone captures most of the dust on and a filter behind the cyclone purifies the rest of the air.

Klik om te vergroten

Are you also looking for an extraction system for your powder coating installation?
We are happy to take a look and can offer you customized, no-obligation advice.

Historical dust extraction and cyclones

In the distant past, Naaykens Luchttechniek already produced systems for dust extraction. Take a look here at what these types of systems and installations used to look like and see how extraction and air technology has evolved.