The Expansion Joints are elements that provide permanent flexibility in a pipe system absorbing the dimensional changes caused by the thermal expansion or contraction of a pipeline, duct or vessel.

The Expansion Joints are flexible elements that, depending on the material grade and its thickness, resist high or low temperatures and are capable of handling corrosive fluids, remaining operative for a prolonged period of time in vacuum or positive pressure condition.

Vilanova y Cruz, S. L. supplies Expansion Joints from DN 15 up to DN 4000.

In our design system for the expansion joint attachments we include the following:

  • The Standards EN-13445; EN-13480; EN-14917; ASME VIII Div. I; ASME B31.1; B31.3.
  • CAD Drawings.
  • 3D Models.
  • Finite Element Analysis.

Vilanova y Cruz. Compensadores de dilatación

Depending on the diameter, our bellows can be supplied for an internal pressure up to PN 64.

The temperature limits depend on the material grade. The standard bellows material is stainless steel 1.4541 (TP 321). Other usual materials are 1.4571 (TP 316 Ti), 1.4404 (TP 316 L) and the type 1.4828 for temperatures over 550 º C. Inconel 625 and Incoloy 825 are applied for special conditions according to these material properties. Other bellows materials could be supplied according to the customer requisitions.

The Expansion Joints are tested pneumatically or hydrostatically and the welding areas are examined with a liquid penetrant test. It is possible to do other types of non-destructive or destructive tests with the collaboration of external entities.

The bellows design is calculated according to E. J. M. A., EN – 14917, AD – Merkblatter, and other international standards.


This is the simplest type of Expansion Joint that can absorb all the movements of the piping configuration into which is installed.

This is the simplest and the most used type of Expansion Joint and consist of a single bellows and ends connections. This Expansion Joint will deflect in any mode of bellows deflection. This type of Expansion Joint will require the most control of the adjacent piping respecting to the guides and anchors. The guides and anchors will be the appropriates to control the pipe expansion according to the Expansion Joint specified values because this type will not resist any force other than the spring force of the bellows, so the main anchors and the directional main anchors will be designed to withstand the forces and moments imposed upon them.


Advantages:
  • The simplest expansion joint to absorb all the movements of the pipe section
  • The flow direction is not modified
  • The lower cost of expansion joints

Requirements:
  • Strong main anchors and appropriate guides system
  • Limited absorption of movements being necessary to shorten the initial pipe configuration in several shorter ones
  • Higher cost due to the increment of fixed points and guides


This Expansion Joint contains two bellows joined by a central pipe or spool for the purpose of absorbing any combination of the three basic movements (Axial, Lateral and Angular).

This type of Expansion Joint is used in cases where the lateral movement is larger than the one suitable for a Single Expansion Joint.

This Expansion Joint contains two bellows separated by a central pipe or spool that accommodate large amounts of lateral movement. The amount of lateral movement is dependant on the angular rotation each bellows can absorb and the distance between the bellows.

This Expansion Joint can also accept axial and angular movements in addition to the lateral, but it does not have restrain hardware to resist the pressure thrust so properly anchors and supports must be provided.


Advantages:
  • Absorption of movements in all directions
  • Used in cases requiring greater amounts of lateral movement than cannot be absorbed by a single expansion joint

Requirements:
  • Not suitable for high pressures
  • Used with main anchors and appropriate guides system


This Expansion Joint has the same characteristics of the Universal Expansion Joint apart from the incorporation of tie rods to restrain the pressure thrust load. This Expansion Joint will not absorb any axial movement excepting the thermal expansion of the central pipe between both bellows.

Whenever an Expansion Joint has installed tie rods, the anchors and supports requirements are greatly reduced from the required for the Unrestrained Expansion Joints.


Advantages:
  • Absorption of lateral movements in all directions
  • Considerable reduction of pressure thrust from the pipe system

Requirements:
  • Do not absorb any axial movement external to the tied length


This Expansion Joint contains a single bellows and is designed to permit angular rotation in one plane only by the use of a pair of pins running through plates attached to the Expansion Joint ends.

Hinged Expansion Joints should be used in sets of 2 or 3 to function properly.

The hinge hardware is designed to restrain the pressure thrust load and other additional specified external loads. The anchors and supports requirements are greatly reduced from the required for the Single Unrestrained Expansion Joints.


Advantages:
  • Designed to permit angular rotation in one plane only
  • Considerable reduction of pressure thrust from the pipe system

Requirements:
  • Installed in sets of two or three units to function properly


This Expansion Joint contains a single bellows and is designed to permit angular rotation in any plane by the use of two pairs of hinges connected to a common floating gimbal ring or box.

The Gimbal Expansion Joint provides the same restrain to axial movement and pressure thrust as the Hinged Expansion Joint and should be used in sets of two or three or in combination with the Hinged Expansion Joints.


Advantages:
  • Designed to permit angular rotations in any plane
  • Considerable reduction of pressure thrust from the pipe system

Requirements:
  • Installed in sets of two or three units to function properly


This Expansion Joint contains one or two bellows with a central pipe and an extra bellows to balance the pressure thrust. Normally it is used at change of direction in the piping and the elbow is mounted between the flow bellows and the balancing bellows.

This Expansion Joint is used in cases where the pressure thrust is considered too high for the equipment to which the pipe system is connected, such as turbines.

The main advantage of this Expansion Joint is its ability to absorb combined axial and lateral movements, transferring to the fixed points only the load due to the bellows spring rate, which is normally of an insignificant magnitude compared to a traditional design.


Advantages:
  • Absorption of axial and lateral combined movements
  • Designed to eliminate the bellows pressure thrust force

Requirements:
  • Need a change of direction in the pipeline
  • High cost


This Expansion Joint has the same characteristics as the Pressure - Balanced Expansion Joints without the change in direction of the piping.

Normally are used in straight and shorts pipe runs where this type of Expansion Joint is essential. The large balancing bellows must have a cross sectional area twice that of the line bellows.



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