Catalogo ABC 54

Notes on correct use of compressed air tools WARNING: our tools must work with compressed air at 5.9-7.8 bar (6-8 atmospheres). It is not enough to make sure that the compressor provides air at these pressure levels, it is also necessary to know how many litres of air it provides and the characteristics (diameter and length of the pipes) of the system. COMPRESSOR Keep in mind that an air intake in litres/1’ or m³ per hour is not the same as the provided air pressure, but is 20-30% less. For an approximate evaluation, one may consider the following basic value: 1 KW in the motor provides about 130 litres/1' at 6.8 bar (7 atmospheres). To calculate how much compressed air is necessary to have to be able to operate a certain number of machines, the consumption values for the individual machines is added, for example: – 1 angle grinder m³/1’ 1.2 = 1200 litres/1’ – 1 drill m³/1’ 0.42 = 420 litres/1’ – 1 screw driver m³/1’ 0.25 = 250 litres/1’ m³/1’ 1.87 = 1870 litres/1’ From the total, subtract the operating coefficient (down time), which varies according to the type of work (about 30-40%), and you obtain the quantity of air required to be able to use the three machines which, in our example, require approximately 1122 litres/1' (a compressor with a 6 KW motor). TANK The capacity of the tank is not decisive in the assessment of which and how many tools can be used on a given compressor. The tank in the compressor serves the purpose of eliminating compression pulsations, to provide a certain amount of air in order to allow for resting periods to cool off the compressing heads, and to avoid frequent interruptions, which cause energy consumption and damage to electrical apparatus, in addition to serving as a compressed air reserve for short operations, during which consumption levels exceed the compressor's capacity. SYSTEM The pipes (in black iron, but preferably galvanised) must have a large diameter because: - In a pipe with a large diameter the air flow has a lower speed, and therefore it is less likely to bring condensed water with it. - In a pipe with a large diameter, the loss of pressure is lower (loss of pressure varies in proportion to the speed squared). - Drops in pressure significantly reduce the power provided by the tool, for example: at 4.9 bar (5 ATM), power is 55% of the power at 6.8 bar (7 ATM). For pipe couplings, it is best to rely on welding as much as possible, leaving only a few flanges for disconnecting and connecting pipes. For coupling pipes with diameters below 2", it is possible to use threaded couplings, The pipe diameter must be: To carry litres/1 1400-500 800-1000 1200-1500 2800-3000 4500-5000 Gas pipe diameter 3/4” 1” 11/2” 2” 21/2” To avoid pressure drops: - Couplings, elbows, and branches with a large radius of curvature - Main pipes closed in ring - Branches as short and straight as possible. - Choice of flexible hose in appropriate diameters and length not exceeding the necessary value. - Avoid branches with a limited cross section as much as possible. To avoid compressed air leaks: - Connection and branch couplings made with care and using watertight mastic (we suggest not using hemp and paste). - Pipe-tool couplings with perfect seal. - Various valves with perfect seal. - Flexible hoses in good condition. It is possible to keep track of drops in pressure during work breaks when all operating points are stopped and there is still a decrease in pressure in the com- pressor's tank. TO PREVENT THE CREATION OF CONDENSED WATER - Air cooler immediately after the compressor - Main pipes with 2-3% gradient compared to the collection tanks - Branches with semi-circular elbow joints on the upper part of the main pipes. - Filters upstream of and as close as possible to each tool. It is best to discharge the condensate from the compressor tank every eight hours of operation. TOOLS These must work: - with compressed air at 5.9 - 7.8 bar (6-8 ATM) - with dry air (purified with condensed air), clean and containing a certain quantity of lubricant it is ABSOLUTELY NECESSARY TO LUBRICATE TOOLS USING THE OILERS INSTALLED UPSTREAM AND AS CLOSE AS POSSIBLE TO THE TOOLS Good lubrication is provided by 3-4 drops of oil (suggested by the tool manufacturers) for 1000 litres/1' of air flow For lower or higher consumption levels, work out how much to use in proportion. We suggest: - With a needle pressure gauge (which penetrates into the flexible hose and does not cause leaks after it is removed), check to see if in the point closest to the tool the pressure value is 6.8 bar (7 ATM). The test must be performed with the tool stopped and with the tool running. The two readings must indicate more or less the same pressure value. - Before attaching a tool, let some air out of the pipe. This helps to expell any water, rust and impurities. - If a tool has not been used for a long time, immerse it in petrol for a few hours and then blow air into it. - Frequently clean the mesh filters, installed in the tool, that prevent damage from impurities, rust, and tartar fragments. - When exposing a sheet of light paper to the air jet, oil spots should appear on the sheet. If this is not the case, the level of lubrication is insufficient Never install quick couplings directly on the tool, because in addition to increasing its weight, it also makes it less comfortable to handle, and when it is dis- connected from the network it is subject to knocks that damage the male joint, leading to a poor air seal. We suggest installing the quick coupling between the tool and the pipe using a rubber hose about 1 metre long. Compared to high frequency electrical tools, compressed air tools: - are lighter and smaller - are safer - are more resistant - are more flexible to operate - Cost more (even the air system costs more, but the air system is not used only to activate the tools). - Cost more to maintain - Do not overheat under stress.