Chapter 8 Power Tools 183
Copyright Goodheart-Willcox Co., Inc.
Pneumatic Power Tools
Another way to supply power to portable tools
is to use pneumatic power, or compressed air or gas.
Pneumatic, or air, tools are driven by compressed
air supplied by an air compressor or by compressed
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delivered from a high-pressure container called
a cylinder.
Air compressors are pumps that collect atmospheric
air into a high-pressure tank. The compressed air
can then be released in controlled amounts through
fl exible hoses to operate power tools. See Figure 8-3.
Compressors may be powered by electricity or by
internal combustion engines. Pneumatic tools usually
operate at 80 to 100 pounds per square inch (psi) of air
pressure. Supply hoses must be reinforced to withstand
this range of pressure and are usually connected to tools
using locking connectors. A few examples of locking
connectors are shown in Figure 8-4.
Pneumatic tools have some advantages over other power tool types.
They typically weigh less than other types and pose less of a spark hazard
than electric tools. This characteristic reduces the fi re risk in environments
where fl ammable gases may be present. Using compressed air as a power
source can also be advantageous when compressed air is also necessary for
other jobs, such as infl ating tires or spray painting.
The size and number of tools that may be operated at one time by a
single air compressor is limited by the cubic feet per minute (cfm) air output
of the compressor. For example, an air compressor capable of a sustained
output of 12 cfm cannot be expected to operate a paint sprayer that requires
7 cfm and a sander that requires 9 cfm at the same time, although it would be
adequate for either one individually.
Compressing atmospheric air concentrates its moisture content. To protect
pneumatic tools from damage, a water fi lter or separator should be installed
in air supply lines. Filters are usually combination units that include a water
separator, a cartridge-type air fi lter, a pressure regulator, and a gauge to monitor
line working pressure. See Figure 8-5. Filters remove large particulates from
the air supply that could cause premature wear within the tool.
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Figure 8-3. Portable and stationary air compressors
are used to provide pneumatic power to operate
tools.
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Figure 8-4. Male and female quick-connect couplers are used to facilitate the connection
of pneumatic tools to compressed air supply lines.