Metal Bellows
- Accessories and
Options
Metal Bellows
are available with weld ends or custom welded flanges
for bolt-up connections. Metal bellows can be supplied in one to three plys in a variety of materials.
Flanges can be provided to match customer bolt patterns.
Fixed and floating flanges available.
Weld ends or pipe ends provide a
way for welding directly to the ductwork.
Beveled or square cut ends are provided.
|
Flow
Liner
 |
|
The flow liner
protects the corrugated metal bellows from abrasion and
reduced buildup of particulate. The liner also helps to provide
a laminar flow. Materials include: carbon steel, corten,
stainless steel and AR plate. |
|
|
Cover
 |
|
The metal bellow cover provided to protect from external
environment and dirt build up. Provided in stainless steel
or galvanized steel. |
|
|
Control Rods/Limit Rods
 |
|
Control rods provide stability and/or limit
movements. This helps over-extension or compression of the
joint which could cause damage. |
|
Bellows Convolutions
The bellows convolution is the element of
the bellows that makes its flexibility possible. Each convolution can be
likened to a pair of thin washers which can deflect easily by bending
parallel to the bellows centerline. The amount of flexibility of each of
these washers is a direct function of the height of the convolution, and
the height is limited by both the pressure and the ability to form the
convolution. Except in a very few applications, a single convolution is
not capable of providing a sufficient amount of movement.
The convolution can only deflect in an
axial direction in any radial plane. Therefore, a single convolution can
only accept movement in an axial direction, or angularly about its
center. A single convolution is incapable of accepting lateral
deflection. Therefore, the metal bellows usually will have several
convolutions. At certain calculable critical pressures each convolution
will experience a deformation of the side walls known as in-plane
instability. Every bellows also has a calculable critical pressure at
which a phenomena known as "squirm" or column instability will occur.
Squirm is similar to column buckling and is an effect exhibited by the
convolutions as a whole, rather than individually as with in-plain
squirm.
Each bellows has been computer designed
and analyzed to assure that each of the above pressure and movement
considerations and limitations have been taken into account.
|
