Metallic Expansion Joints - Thorburn Flex Inc

THORBURN
FLEXIBLE PIPING SPECIALIST
IN-LINE PRESSURE BALANCED UNIVERSAL
FEATURES
■ Eliminates pressure thrust
■ Conserves space
■ Eliminates main anchors
■ Does not require a change in direction of the piping system
UNIVERSAL SERIES
Thorburn Model IPBU in-line pressure balanced expansion joint will
absorb thermal motion while eliminating the pressure thrust loads
on a piping system without a change in direction of the piping.
The unique design of this in-line pressure balanced joint consists
of a constant volume device which is created by the addition of two
balancing bellows whose difference in cross-sectional area is exactly
twice the cross-sectional area of the line bellows. By proper crosslinking,
the change in volume of the line bellows, due to a change in
length (i.e. compression and/or extension) can be made to cause
an equal but opposite change in volume of the balancing bellows.
Thus, since the volume changes are of an equal value, the pressure
forces that are normally present in a piping system containing
bellows expansion joints are eliminated.
Thorburn Model IPBU universal series expansion joints
are used where the location of the expansion joint
prohibits or makes it very costly to install main anchors.
EXTERNALLY PRESSURIZED IN-LINE PRESSURE BALANCED
EXPANSION JOINT SERIES IPBE
Thorburn's IPBE expansion joint is an in-line, externally pressurized pressure
balanced expansion joint. This type of expansion joint is capable of long
axial movements at high pressures and at the same time eliminates pressure
thrust forces on the system. Main anchors are no longer required.
In-line externally pressure balanced Model
IPBE absorbs large axial motion.
In order to accomplish this balancing, a constant volume device is used by the
addition of a balancing bellows with a cross-sectional area equal to twice the crosssectional
area of the line or pipe size bellows. Through proper cross-linking, the change
in volume of the line bellows, due to an axial change in lentgh, i.e. expansion or contraction, can be made to cause an
equal but opposite change in volume of the balancing bellows. Therefore, if a contraction of the pipe occurs, an equal
expansion can be made to occur in the balancing bellows. Using the principles of mechanics and hydraulics, if no volume
change occurs, then all pressure forces remain constant and there are no forces out of balance. Thus the pressure thrust
that would normally be present in a piping system containing an expansion joint is eliminated.
This unique design incorporates integral guide rings, a full thickness cover, self-draining convolutions and insensitivity to
flow. It is easy to insulate and easy to handle during installation.
Similar to the standard Thorburn Extra-Flex expansion joint, it can be supplied either as a single or double. Either type can
be supplied with a support foot which would act as an intermediate anchor.
If high pressure thrust loads are causing the design of main anchors to be prohibitively costly and/or difficult, eliminate
them by using Thorburn IPBE expansion joints.
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