Bellows Movements

Explanation of Movements
A key attribute of bellows is their ability to move in response to stresses placed upon them by the equipment to which they are mounted, whether such stresses are generated by expansion and contraction or plant vibration.
There are three key types of movement for which a bellows is designed.  The specification for the amounts of these movements is given on the individual product nominal bore pages.  It is important to understand that these movements are not independent, for combined movements please contact us.  Bellows are not designed for rotational movement around the principal axis.
The mechanical design of the flanges, tie rods and limit sleeves are to assist in restricting the bellows movement within these safe ranges and are fundamental to the design.  It may be necessary to restrict movement still further and special bellows are available for these purposes.  Hinged bellows allow angular movement only, whilst lateral bellows with spherical washers allow lateral movement only.



This is the most frequently required type of movement and is specified in terms of the bellows minimum and maximum extension and its neutral length.  The neutral length is the mid-range position at which the bellows is set when shipped from the factory and should be as close to the installed length as possible.  Bellows can be installed at lengths between the minimum and maximum length, but this of course will restrict the amount of allowable movement


Lateral Movement

Lateral movement is at right angles to the principal axis.



Angular movement is the movement of the flanges out of parallel.


Universal Bellows

These consist of two special hinged bellows in series to provide double the lateral or axial movement.

We publish allowable movements for our bellows in our catalogue, however maximum movments in all planes at the same time are not permitted. To help you check that you are specifying your bellows correctly we recommend you make use of our free online bellows configurator programme which will check and confirm your chosen bellows is safe for your application. 
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Contact Details

Corrosion Resistant Products Ltd
Todmorden Road
OL15 9EG

Phone: +44(0)1706 756400
Fax: +44(0)1706 379567