There are many ways to blowoff, cool, and/or dry materials. A few of these methods are the drilled pipe, an array of flat nozzles, using a blower driven air knife and the EXAIR Super Air Knife. We’ll examine each in further detail, for blowoff of water after a bottling cleaning operation. Testing was done at 60 PSIG of supply pressure. The blower utilized a 10 hp motor and was a centrifugal type spinning at 18,000 RPM. Sound levels were taken with product not present to test the sound of each of the blowoff types.
Drilled pipe is a common blowoff because it is very inexpensive and easy to make. But drilled pipe performs poorly. The low cost to make the drilled pipe is quickly outpaced by the inefficiency and high compressed air costs. The holes are easily blocked and the noise level is excessive, both of which violate OSHA requirements. Also, the air pattern across the length can be very inconsistent, with areas of low flow and areas of turbulent flow.
Flat air nozzles installed along a length of pipe is another inexpensive option, but it can be a poor performer. The flat nozzles are available in many materials, from many manufacturers. The flat nozzles do offer some efficiencies, but similar to drilled pipe, the operating costs and noise levels are high. Air pattern across the length can be inconsistent with areas of high and low flows, leading to incomplete drying or cooling. Also, many of these nozzles are made from plastic material which breaks or cracks when it it hit which causes additional expense and maintenance to replace broken nozzles.
A blower air knife can prove to be an expensive and noisy option. Typically, the initial purchase price is high. Operating costs are lower than the drilled pipe and flat nozzles and in line with the Super Air Knives. The blowers can be very large and space for two 3″ diameter hoses requires extra mounting space compared to low profile other options. Noise levels are high, at 90 dBA. Annual costs for bearing and filter maintenance can be significant.
EXAIR Super Air Knives performed exceptionally well in removing the water in one pass due to the strong, laminar flow of air. Sound level was low at just 69 dBA, well within OSHA requirements for an hour 8 hour exposure time. Safe operation is assured, as the Super Air Knife design cannot be dead-ended. Maintenance costs are low, as the Super Air Knife has no moving parts to breakdown or wear out.
Ultimately, the Super Air Knife is a low cost way to blowoff, dry, clean and cool.
If you have questions about Super Air Knives, or would like to talk about any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
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