Lateral expansion joints are used to absorb lateral deflection. Lateral expansion joints can move in all lateral directions simultaneously for absorbing expansion from two pipe sections in different directions. The lateral expansion joint is normally equipped with fixtures such as external tie rods, which allow the unit to absorb movements in all lateral directions but also to absorb the pressure thrust (incl. full vacuum).
DIMENSIONS OF LATERAL EXPANSION JOINTS
Belman designs and manufactures a wide range of lateral expansion joints.
As customised solutions lateral expansion joints are available in all sizes up to DN 12.000, all designs and all materials.
As standard solutions lateral expansion joints are available in size range DN 50 – 2000.
TYPES OF LATERAL EXPANSION JOINTS
Comprehensive technical data and selection criteria for +3500 standard metallic expansion joints.
CUSTOMISED LATERAL EXPANSION JOINTS
TECHNICAL DESCRIPTION OF LATERAL EXPANSION JOINTS
The lateral expansion joints are available with one or two bellows (universal type) as well as with a number of end connections like welding ends, flanges and/or a combination thereof. Additionally, it can be equipped with accessories like: inner sleeves, covers,
intermediate pipe and tie rods.
The type of expansion joint selected depends on both its cost effectiveness and its suitability for the function to be fulfilled. The economic consideration should not only take into account the cost of the expansion joints, but also the required fix points, guides and structures.
Lateral movement is a sideways (lateral) displacement of the ends of the expansion joint in a direction perpendicular to its longitudinal axis. Lateral movement can be absorbed both in the horizontal and the vertical axis/direction according to the design of the pipe system. Lateral movement can, to a limited degree, be absorbed by one bellow. If larger movements are to be absorbed, we recommend a design with a universal expansion joint (two bellows with an intermediate pipe) absorbing the movement and this also results in lower offset forces.
Lateral movement is shown as LA and stated in mm. The parallel displacement is indicated as
negative (-) and positive (+).
The elongation of one side of the bellow is +10 and the compression of the other side of the bellow is -20. This will be shown as: LA +10/-20 mm. Equal parallel displacement is shown as: LA +/-20 mm (2λN).
APPLICATION OF LATERAL EXPANSION JOINTS
As lateral expansion joints absorb movements in lateral directions in one or more planes, and absorb adjusting forces, they are widely used in more complex pipe systems with many different directions and levels.
Lateral expansion joints make possible the absorption of movements which are perpendicular to the longitudinal direction of the pipeline, and are therefore ideal for installation in pipe systems with bends, Z shaped pipe systems and in 3 hinged systems.
ADVANTAGES & REQUIREMENTS
What are the advantages of using Lateral expansion joints?
- Absorb movements in all lateral directions
- Absorption of large lateral movements with only one lateral expansion joint
- Reduced loads on all fix points as the tie rods on the lateral expansion joints absorb the loads without transferring pressure thrust on to the fix points
What are the requirements for Lateral expansion joints?
- For absorption of large expansions several lateral expansion joints are needed
- Many fix points and guides are needed for long pipe sections
PIPE WORK GUIDELINES
Expansion joint installed in the short piping leg
The configuration is an alternative arrangement in which the expansion joint is installed in the short piping leg and the principal expansion is absorbed as lateral deflection.
The longer piping leg is free of compressive pressure loading and requires only fix points and a guide (Gn).
Tie rods to prevent axial movement
A piping configuration that permits the use of adapted tie rods to prevent axial movement frequently simplifies and reduces the cost of the installation.
Due to the tie rods, the expansion joint is incapable of absorbing any axial movement other than its own thermal expansion. The thermal expansion of the piping in the shorter leg is, as
a result, imposed as deflection on the longer piping leg. Where the longer piping leg is not sufficiently flexible and where the dimension of the shorter leg is suitable, tie rods may be installed spanning the entire short leg so that no deflection is imposed on the longer run from its source.