Air Cylinders
Air cylinders are used in applications ranging from crust breakers in the steel
industry to wafer processing in the semiconductor industry. For this reason,
manufacturers have developed many different styles of cylinders with many
different operating characteristics, some of which are highlighted below.
Stainless body air cylinders are sometimes referred to as "throwaway" cylinders,
due to the fact that they are non-repairable. Generally these cylinders are
the least expensive option.
These cylinders are available in both imperial and metric. The metric
cylinders generally conform to the ISO 6342 standard. For the imperial
cylinders, there is no official industry standard, but most manufacturers'
cylinders are interchangeable.
Generally these cylinders have anodized aluminum heads, a stainless tube, and a
stainless steel piston rod.
"Tie-rod cylinder" is a generic term for an air cylinder with a square head and
cap,
and 4 bolts (tie-rods) holding the cylinder together.
There are 2 different standards that fall under the
"tie-rod" category. The NFPA cylinder is the North American standard, ISO 6431
is the European standard.
Some companies also make tie-rod cylinders that do not conform to either
standard.
Rodless cylinders are a space-saving alternative to standard rod-style air
cylinders.
There are several different styles of rodless cylinder:
Band Cylinders
- the carriage rides along the length of the cylinder body. The
carriage is connected to the piston through a slot along the top of the
cylinder. This slot is sealed with stainless or plastic bands.
Cable Cylinders
- the yoke is connected to the piston by 2 cables that run
along the cylinder, around a pulley and into the end of the cylinder caps.
Through the use of pulleys, the effective stroke of the cylinder can be
doubled. Also by wrapping the cable around an external pulley, rotary motion
can be created.
Magnetically-Coupled Cylinders
- the carriage is connected to the piston
through a strong magnet. This design does not allow contamination to enter the
cylinder, but loading is limited by the strength of the magnet.
Many manufacturers make a low-profile cylinder for applications where there is
not enough space for a standard length cylinder.
Generally, compact cylinders have very little tolerance for side-loading due to
their design.
There is no standard for the dimensions of compact cylinders, but just as in
the stainless body cylinders, several manufacturers make an interchangeable
design.
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