Woodworker's Journal 1994-18-1, страница 12
mlt^ Shoptest Penn State Air Cleaning System Breathing wood dust was once accepted by woodworkers as something they had no choice but to tolerate. Little thought was given to any health implications. Fortunately, times have changed and today most of us are aware of the respiratory problems associated with breathing dust laden air. The battle against dust is fought on many fronts. It's always best to collect as much dust as possible directly at ihe source (usually either through stationary tool hookups to a central dust collection system, or through dust bags on smaller tools), but what about all that free-floating dust that inevitably escapes our best dust collection efforts? Fnier the air cleaner, a unit designed to collect and trap airborne dust. Air Cleaning System No. 460 Penn Slate's Air Cleaning System No. 460 is a blower and two stage filtration system, housed within a 12 in. x 24 in. x 30 in. sheet metal box. A squirrel cage blower rated at 460 CFM (cubic feet per minute) draws shop air through a pre-filtcr and then a finer filter bag before exhausting the cleansed air back into the room. It weighs about 40 pounds. .">8 Location and Use The system can be used in a central location (usually mounted near the ceiling), or as a portable unit that is located close lo the dust source. In the fixed location just turn on the air cleaner and lei it run. The blower is relatively quiet, and with Dust panicle diameter is usually measured in microns. One micron is 0.001 millimeters or about 40 millionths of an inch. To give some points of reference, the naked eye can see individual particles as small as 10 microns. Panicles between 10 microns and 0.1 microns are seen as clouds, haze or smoke. Your nose and mouth will typically filter particles down to 15 microns. Panicles smaller than 15 microns arc rcspirable, meaning that they are drawn into the lungs. Tobacco smoke, for example is about 0.3 microns. its 460 CFM rating, it will make one air change every 10 minutes in a 4600 cubic foot shop (such as a 24 ft. x 24 ft. garage with an 8 ft. ceiling). As a portable unit, try to locale the niter grill as close lo the dust source. I tested the air cleaner with a smoke generator, and found thai working within 20 in. of ihe grill resulted in most of the dust being collected. As 1 started the test. I noticed thai some haze was coming through the system, but after ihe unit was running for a short while (allow ing the filler bag lo accumulate a lining of dust), the haze slopped. It takes this internal lining of dust for the filter to work its best. The standard filter bag is rated to slop particles as small as 8 to 10 microns. A high filtration bag is available for particles down to 1 micron. Cleaning The pre-filter should be cleaned periodically, which is easy to do using warm water and a mild deicrgent. The filter bag should be removed and shaken out when the air flow slows noticeably or when filtration is nol satisfactory. Penn State cautions thai the filter bag itself should not be washed. And, keep in mind that the pre-filter should be completely dry before it is reinstalled, since any remaining water will result in dust caking to the filter material, thereby reducing efficiency. The filter hag is a standard triple-pleat material, and is available either from Penn Stale or your local heating, ventilation and air conditioning supply house. Summary As staled earlier, the air eleaner is not a replacement for a saw dust or chip collector. Its mission is to trap fine suspended particles and this it does quite well. The Penn Stale Air Cleaning System will help to keep your shop environment pleasant and healthy. Penn State Industries, Depl. J. 2850 Comley Road, Philadelphia, PA 19154; tel. 1-800^377-7297. Air cleaner sells for about $279.95 plus S10 shipping. E3j The Woodworker's Journal |
