Avoid frequent air filter replacements and wearing air compressors with RTS Africa’s spin filter.

The RTS Africa spin filter will remove 98% of 15 μm particles, above 93% of 10 μm particles, and 80% of 5 μm particles. By using the inertial spin filter to remove most of coarser particles from the air entering a compressor room, the compressor’s own filters will need to be replaced far less frequently.


A spin filter consists of cyclone-shaped tube, through which air is propelled or drawn. On entering the tube, the air is induced to spin using vanes. Particles in the tube move to the outside of the vortex, and the clean air in the vortex centre exits through a central orifice at the end of the tube. A secondary stream of air is used to evacuate the dust-laden air back to where it came from.

In an alternative application, spin filters can be very useful in the direct ventilation of variable speed drives (VSDs). These are used on many compressors and need to be consistently and continuously cooled.

Managing Director of RTS Africa Engineering, Ian Fraser, explains, “The use of a spin filter is a truly effective means of feeding clean air at ambient temperatures to VSDs within a compressor room environment.”

RTS has developed a technique called ‘back-channel cooling’ of variable speed drives (VSD). In the past, to cool compressor VSDs, the entire compressor room would be air-conditioned at considerable installation and running cost. 

The air from a spin filter can be used to fill the entire compressor room with clean, dust-free air. Fraser says, “As VSDs will run efficiently at temperatures of 40 to 50˚C, expensive air conditioning is not needed,” Fraser adds.

As an alternative, if air needs to be channelled to specific VSDs, air from spin filters is directed along a plenum at the back of the compressors, from where it is drawn by fans into the various VSDs. The air is supplied at about 100 Pascals pressure, which is sufficient to maintain a slightly positive pressure. The air then passes through the VSDs and is vented out to the exterior of the VSD room.

RTS Africa Engineering spin filters: back channel cooling

RTS Africa Engineering spin filters: back channel cooling