Rubber Expansion Joints

Full Face Rubber Flanged Expansion Joints


High quality custom-made expansion joints supplied with split or fixed steel backing flanges. The full face flanges are integral with the body of the joint and drilled to conform the bolt pattern of the companion flanges of the pipe line.

Rubber bellows: Reinforced EPDM, EPDM HT, Nitrile, Spec. Nitrile, Nitrile white, Hypalon, SBR, Viton®, Chloroprene, etc.

Flanges: shot-blasted and painted carbon steel as standard. Also available in hot dip galvanized carbon steel, stainless steel, etc. Drilled to EN, ANSI, AWWA, JIS standards or any specific dimension.

For vacuum applications, an internal vacuum ring is incorporated.

MAC-F and MAC-FT can be supplied with one or more arches. Dimensions from DN 15 to DN 6000.



A high-quality custom made single arch unrestrained expansion joint consisting of a rubber bellow incorporating full face rubber flanges and metal backing flanges.

This model absorbs all the movements in any one length of piping.

Unrestrained expansion joints under pressure will exert a considerable axial force on the pipeline, i.e. anchors. It is essential that checks are carried out when the expansion joint is first pressurized to ensure that there is no unforeseen stretching of the bellows. If unforeseen movement is apparent, then the pipe guides or anchors shall be examined to ensure that they have been installed correctly and sufficiently designed for the duty.



Expansion joints expand in length when under pressure. The force created by this pressure is designated as Pressure thrust. Where the pipe supports and anchors are not designed to absorb this force, tie rods across the joint must be incorporated. Tie rods are designed to take the full pressure thrust and tie rods supports are integrated in the flanges (retaining rings) so there is no thrust on counter flanges.

Recommended on most applications to prevent damage due to excessive pipe movements, each rod incorporates double nuts on each end to keep the expansion joint from over elongating and spherical washers to allow lateral and some angular
movements (2 tie rods only).


MAC-FP / Hinged

These expansion joints can be fabricated as a single and multiple arched elements with flanged connections, plus a system of articular supports that allow for angular movement in one plane only.
The hinged mechanism is designed to accept full pressure thrust.
These expansion joints can be fabricated with more than one convolution.
These units do not allow axial movement. However,some types of hinged systems can be provided with slotted holes for the hinge pins, to allow limited axial displacement. The “slotted hinge” units cannot resist the pressure thrust forces and therefore proper anchorage must be provided.


MAC-FC / Gimbal

Gimbal Expansion Joints are designed to allow angular movement in any plane by the use of two pairs of hinges affixed to a common floating gimbal ring.
These expansion joints can be fabricated with single and multiple arches.
The gimbal ring, hinge and pins, are designed to restrain the pressure thrust due to internal pressure and shear forces.
A gimbal ring is either round or square.
For round gimbals the torsional moment shall be considered and for square gimbals the instability due to the bending shall be considered.


MAC-FB In-line

MAC-FB Elbow

MAC-FB Elbow

These expansion joints accommodate axial and lateral movements and counteract the bellows pressure thrust. They can be fabricated with single and multiple arches.
An additional bellows is incorporated into the unit and is subject to the line pressure to generate a force equal and opposite to that on the main bellows. Tying these bellows together neutralizes the pressure load on the unit.
The Pressure Balanced Expansion Joints are used in situations similar to those described for the Axial and/or Lateral Expansions, although this particular type of Expansion Joint offers the additional advantage of not transferring the thrust caused by the internal pressure to the pipes or adjacent equipment.

This characteristic is especially important when it comes to joining the pipes to turbines or other delicate equipment which, by their nature, are unable to withstand these extra loads. The only loads on the equipment are the sum of the forces required to move the line bellows and balancing bellows of the expansion joint.
This type of Joint can be fitted between intermediate fixed points so main anchoring of the pipe or adjacent equipment is not required.


MAC-FR / Rectangular

Rectangular Expansion Joints are generally designed for low positive pressure and vacuum applications in the power, chemical, petrochemical, and steel
These expansion joints can be fabricated with single and multiple arches. Due to the fact that there are no standard dimensions for rectangular pipes, each rectangular expansion joint is custom designed. They can be built with more than one convolution.
Regardless of accessories, such as tie rods, hinges, liners, covers, etc. these models absorb all the movements in any one length of piping, but are mainly used to absorb axial movements. Like circular expansion joints, unrestrained units do not contain pressure thrust so adequate anchors and guides must be provided, and they can be used only in piping systems that incorporate correctly designed anchors and pipe alignment guides.

MAC-O / Unrestrained

MAC-O / Unrestrained

These expansion joints can be fabricated with single and multiple arches, or in a simple sleeve configuration, each for use with the clamped connection (clamps can be supplied, upon request).
The MAC-O is recommended for use in services with a maximum pressure of 0,30 barg, and is wellsuited for loading and unloading processes, with outstanding performance when used for media containing solids. It is fabricated in standard and custom diameters for use with piping, elbows, or reducers.
Regardless of accessories, such as liners and covers, it can absorb all of the movements in any one length of piping.