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Rubber
Bellows
(Expansion Joints)
Descriptions
Rubber
Bellows (expansion joints) are used
to
- Prevent vibration and
sound insulation
- Accommodate axial,
lateral or angular movements or a combination of
these
- Prevent stress due to expansion and
contraction
- Compensate
misalignment
They are widely used
in
-
Refineries
-
Chemical plants
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Cement plants
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Agro/fertilizers
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Tyre industry
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Nuclear & thermal power stations
Design
| The
expansion joints are designed, fabricated and
tested to provide an accurate and effective
solution to the customer's requirements. Rubber
bellows are manufactured as per manufacturer's
standard.
The number, shape and construction of the
convolution depend on the movement, pressure,
temperature, media and fatigue life.
A combination of experience, calculation
and practical testing make a good bellow, which
is critical in order to give the level of
performance as required.
While designing a bellow following
parameters are taken into consideration,
Pressure, Temperature, Corrosion resistance,
Minimum maintenance, Durability, Reliability,
Long life, Economy, Performance and
Safety. |
Construction
Tube
| The
tube is a single piece of extruded leak-proof
lining extending from flange to flange. Tubes
shall be made of different rubber polymer for
different application as per customer's
requirement
Reinforcements
Carcass
High
strength woven polyester fabric between the tube
and cover, this fabric is thoroughly impregnated
with a special friction compound to give medium
adhesion under pressure, vacuum and stress
conditions
Steel
To give maximum
strength to bellows while under pressure or
vacuum service, solid round steel rings embedded
in the carcass. Helical wire also embedded to
give additional strength.
Cover
This is the
exterior portion of Bellow, and shall be made of
abrasion resistant neoprene rubber or as per
customer's requirement.
Rubber Moulded
Flanges
Flanges are full faced and
made an integral part of the joint. No gasket is
required for joining the mating flange to the
bellow.
Steel retaining
rings
Steel retaining
rings are made of flat steel and can be of
split, beveled or plated as per installation
requirement. |
Types
-
No arch
-
Single/wide arch
-
Multiple arches
-
Rectangular
Bellows Motion/
Movement
| Axial
Compression
|
Reduction of face to face
dimension measured along the
axis |
| Axial
Elongation
|
Increase of face to face dimensions
measured along the axis |
| Transverse or Lateral
Movement
|
The movement of the joint
perpendicular to the axis |
| Vibration absorption |
The movement of the joint due to
vibrations which are effectively intercepted
and insulated against transmission to
remainder of system |
| Angular
Movement |
The displacement of the
longitudinal axis of the joint from its initial
straight
line position (a combination
of axial elongation and axial
compression) |
Rubber
Bellows Accessories
Flow Liner
The flow liner protects the
corrugated rubber bellows from abrasion and
reduced build-up of particulate. The liner also
helps to provide a laminar flow. Available in
materials like carbon steel, coter, stainless
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.
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|
End Connection
Flanged or
clamped.
|
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How Bellows fail
Pre-Maturity?
-
Faulty piping design
- Incorrect stress
analysis
-
Improper erection
- Un-closed piping system
i.e. not having sufficient anchors and
guides
- Mechanical dents/bends on
convolutions
- Improper selection of rubber
polymer |
