Budget friendly dust removal

24.02.2024 06:20

This article is a byproduct of the effort to design a consumer-grade cyclone filter. A project dated 2021. It has been riding on the back of Dyson vacs. The difference is in lower price and universal applicability. Dyson products are expensive and are meant for dwellings. A workshop wouldn't be able to economically justify such a tool. Nor will it be particularly effective. The results are somewhat self-evident. Compare the two charts below.

A weak cyclone would have been a 3D printed, or molded in China sub $20 cyclone powered by a household vacuum cleaner (air flow 15-70 liters/sec, pressure differential 7-15 kPa). 

A big cyclone would have been the same cyclone with an industrial vacuum cleaner (air flow 40-120 liters/sec, pressure differential 18-30 kPa).

Note that the key effect for big setup is provided by the actual air flow, and for weak setup by the effective pressure differential. Those parameters should be maximized while selecting the power source. It seems, that for practical reasons there is no sense to deploy any household vac. The job can be done by some sort of brooming and collecting the garbage. 

Adding a vent to the suction pipeline that leads towards an industrial vac can help to control the preferred mode operandi: air flow vs pressure differential. It will greatly increase scope of targeted dust, hence increase tool universality. Single path cyclone efficiency is expected in the range 88-97%. It is slightly worse than filtering elements 90-99,8%, and on paar with electrostatic filtering 80-96%. 

Higher air volume leads eventually to a flow shortcut inside the cyclones. Therefore the cyclone size has to be increased if the particle weight diminishes. A more economical option would be to put a HEPA 13 (and up to 16) filter serially after the cyclone. The combined filtering efficiency would be above 96%.

Recommendations:

• 20 kPa pressure differential should be your minimal vac threshold. The higher the better.

• 60 liters/sec air flow should be your minimal vac threshold. The higher the better.

• HEPA 12 and lower are to be avoided. Even the inferior vac models are capable to do better, i.e. to provide class L filtration, i.e. 99% filtering for 2 micro meters particles. 

• Strive for class M filtration and higher. ULPA filter is the ideal.

• each HEPA filter reduces pressure differential by 4-5 kPa. A hybrid setup requires better power source.

• a parallel setup with several small cyclones is better than one big cyclone.