MACOGA. Expansion Joints MACOGA
Metal Expansion Joints
Intro to Expansion JointsManufacture and DesignQuality Control and TestingTypes of Expansion JointsAssembly Instructions and Safety Recommendations
Manufacture and Design
MACOGA Expansion Joints are designed, manufactured and tested in accordance with:

E.J.M.A. (Expansion Joint Manufacturers Association, Inc.)
ASME VIII, Div. I, App. 26
EN 14917, European Standard for Metal Expansion Joints.

If specially requested or included in the terms of the contract, the Expansion Joints can also be designed according to various international standards and codes, including the following:
AD-Merkblatter B13, Stoomwezen D 0901, Suomen SFS 2773, CODAP.

Design control and modifications are set out in the latest version of our Quality Control Manual and the Quality Procedure 'Design and Calculation'.

Manufacturing Methods
MACOGA uses different methods for producing the bellows depending upon a range of different contributing factors (eg. diameters, the number of sheets used, the materials used, etc.), although in all cases the bellows are manufactured using seamless tubes or metal cylinders welded along their length. The methods used are as follows: Expanding, Elastomeric, Hydraulic and Roll forming.

Our manufacturing range includes Circular Expansion Joints of the following types:

> Axial
> Hinged
> Gimbal
> Lateral
> Pressure Balanced
> Jacketed
> Externally Pressurized


as well as Rectangular Expansion Joints which, with limitless dimensions, can be supplied with different convolution and corner types:

> V-shaped - Camera Corner
> V-shaped - Miter Corner (single or double)
> U-shaped - Rounded Corner


Circular Expansion Joints are manufactured with single or multiple ply with a diameter ranging from 15 to 8000 mm.

The use of circular multiply bellows are the ideal solution for Expansion Joints which are exposed to high pressures. This system involves constructing a bellows using several thin sheets instead of one single thick ply. This technique considerably improves the flexibility of the bellows, its most important characteristic.

There are five main advantages to be gained from using multiply bellows:

> They are highly resistant to high pressures.
> They maintain a high degree of flexibility even when working under
   high pressures.
> They have lower spring rates than the single thick sheet bellows.
> They have a high absorption rate for movements across short lengths
   thus ensuring a longer working life.


They guarantee important savings:

> Few units are required within any given system owing to their
   greater capacity to absorb movements.
> The low spring rates reduce the costs incurred by anchorage and
   supporting structures.
> To avoid corrosion, special materials (eg. Inconel, Incoloy, etc.) can be
   applied to the inner layer in order to protect against temperature and
   corrosion and austenitic steel can be used to cover the remaining layers
   in order to withstand high pressures.


Materials Used
The essential component of an Expansion Joint resides in the degree flexibility of its bellows and this depends upon the design of its convolution and the materials used during the production process.
The choice of materials to be used in manufacturing the bellows, being the basic component of the Expansion Joint, is made taking the following criteria into account:

> Temperature resistance.
> Resistance to corrosion.
> Forming capacity.
> Mechanical characteristics.
> Resistance to fatigue.
> Flexibility when in use.


The following is a list of the materials mostly used to produce our bellows:

Stainless Steel Grades
Stainless Steel Grades
254 SMO and 253 MA are trademarks of Outokumpu Stainless

Nickel Alloys

Inconel, Monel & Incoloy are trademarks of Special Metals Corporation
Hastelloy is a trademark of Haynes International, Inc.