Keeping the dust at bay

A turbocharged diesel in a big dozer uses just short of 20,000 gallons of air for every one gallon of diesel fuel burnt. At that rate, air filtration takes on a whole new perspective.

Agriemach Ltd offers a vast range of spark arresters, exhaust gas purifiers and engine air intake precleaners which have been approved and fitted to a growing number of household names in the construction, on-off highway and industrial sectors. 'The trouble with air cleaners is that every engine has one and by implication it is therefore the best available for a given application,' says Agriemach md George Kallmann.

'The truth is that you may well find the same filter being used in marine applications, where dust is the least of the problems, and quarrying or agriculture, where airborne dust represents the major danger to engine life.

'Far less spectacular but no less important, is the amount of money a properly designed intake system can save,' says Kallmann. 'A four stroke engine spends around 25% of its life working as a pump, sucking in air, and anything that restricts that intake of air will result in higher fuel consumption or loss of power.

'Some restriction is necessary. A good system with a clean filter should create an initial reading of less than 12 inches of vacuum at maximum rpm. The best layouts will register between 5 to 10 inches of restriction when clean, but the one thing that is certain is that it is going to get dirty and start to clog.

'One way of reducing filter change frequency is to fit a precleaner, of which there are five main types available. I have no intention of knocking the opposition, but we are so sure of our Turbo 11 precleaner performance that we will let customers try it on a 30-day sale or return basis,' adds Kallmann.

Agriemach's Turbo 11 works on exactly the same principle as all other precleaners - centrifugal force to direct the heavier airborne particles of dust out of the intake before they reach the filter. The Turbo 11uses a spinner to promote even higher radial velocities in the incoming air to prevent more dust from the filter. As air enters through the vanes at the top of the unit, it swirls in a large radius around the centre dome. Then, as the air spins down below the dome and into the intake stack, the radius of the spiral becomes much smaller, increasing the speed. In fact the velocity more than doubles and it is this air stream that drives the spinner.

Because the outer blades of the spinner are turning faster than the incoming air it becomes a blower, forcing dust down and out through the ports at the bottom. It works. Huntsman quarry in Gloucestershire reports that in some instances it was changing filters twice a week. Adding Turbo 11 has increased the working life by a factor of six.

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