Current industrial filtration methods often require costly maintenance and filter membrane replacement on an ongoing basis. However, Rand Technical Services (RTS) has introduced onto the market a robust, highly effective inertial spin filter technology for industrial dust and exhaust separation, which is virtually maintenance free, says RTS chairperson Ian Fraser.

“Spin filter units are a high-efficiency application of cyclone technology. Air which needs to be separated is blown through a module that consists of a series of small vortexes. “The air flow is induced to spin by fixed vanes at the entry to the vortexes, and centrifugal force then drives the dirt particles to the outside of the vortex,” says Fraser.

The dirt-laden air is purged through an annular port at the end of the vortex tube. A purge fan is used to keep the dirt-laden waste air in flight, from where it is either dispersed or collected, as required. Clean air then exits the process, he says, adding that 98% of particles 15 μm and larger are removed by this simple process.

He explains that in some industries this is particularly useful for materials reclamation, as the environment is protected and, at the same time, valuable fines that would otherwise be lost into the atmosphere are recovered.

Unlike conventional filter membranes, which clog owing to pressure build-up after a period of use, the pressure drop across the spin filter module never increases. The units are self-cleaning, and do not block when correctly installed, thereby offer-ing consistent performance with constant resistance. The units are also highly energy efficient, as the pressure-drop through the use of the spin filter is constant and does not increase as dust is removed.

“Not only is pressure constant for the life of the unit, but the unit itself has an excep- tionally long working life. We have instal-lations that are 23 years old and still going strong. “The sturdy, high-density polypropylene construction of the blocks is highly resistant to erosion. “Spin filters are proving to be very effective in mining applications with heavy dust loads. This technology is finding wide application in coal, gold, diamond and other mining environments and is also meeting arduous dust removal challenges in underground applications.

“We have built up a population of spin filters in mining and other industries in control rooms, transformer rooms, machinery spaces and workshops, to name but a few. “This technology has also proven effective for the cooling of variable-speed drive instal-lations,” notes Fraser.

Further, he says, the spin filters are con-structed in modules that can be built up into large panels, sized to match the required air flow, thereby offering an unlimited capacity on engineered systems. The smallest available unit, containing one inertial spin filter module, handles 1 200 Nm3 to 2 500 Nm3 an hour with ease, and upper range capacity is only determined by the application and the available space.

Delivering a rapid return on investment, the spin filter system has an excellent record in areas such as power stations, glass plants, cement factories and steel mills.

Spin filters provide sufficient filtration for most environmental applications, such as transformer rooms and control rooms, with-out the addition of secondary filters. In applications requiring secondary filters to remove finer particles, such as in air com-pressor intakes, the spin filters substantially extend the life of the secondary filters. Conventional filter mem-branes are left with very low dust loadings and so last far longer.

There is also a beneficial ripple effect on cost saving throughout the plant. Downtime due to both planned and unplanned shutdowns is greatly reduced – less damaging friction from dust particles means far less equipment wear and tear, or failure, says Fraser.

A substantial reduction in switchgear and other electrical system breakdowns is achieved once spin filters are installed. Even when planned main-tenance for other equipment is delayed or overlooked, the units deliver consistent, maintenance-free performance to keep elec-trical systems functioning reliably.

Fraser goes on to state that the benefits of the spin filter system are almost endless. “Return on investment is rapid, owing to a substantially smaller spend on filtration maintenance and replacement, not to mention the ongoing reduction in equipment break-downs and support costs. “Environmental benefits are also considerable, owing to the reduction in undesirable emis-sions.”

He explains that, without fil-tration, many processes would literally grind to a halt, and pol-lution and unhealthy working conditions would increase greatly. The inertial spin filter has suc- ceeded on its own proven merits, even during depressed economic conditions, as it keeps on saving time, labour and money long after it has paid for itself.