Even if you are a professional researching information on metal bellows for technical solutions and for installation of industrial processes, it can sometimes be helpful (even to the professional) to gain an overview of the product, what it can do, and just what situations it has been developed for.



This guide will give you a few general pointers, and hopefully answer some of the questions you have. Of course, it is a guide only; for detailed answers to any specific questions you have about projects you may have in mind, we recommend contacting an expert in the field.

What does a metal bellows actually do?

A metal bellows is the term for an attachment on piping typically designed to absorb and mitigate the effects of directional change and to minimize any issues arising from this such as clogging, pressure points on the bend, or expansion of the joint.

It is a development of the basic expansion joint idea used on installations like rail tracks to deal with the expansion and contraction of metal. The central concept to keep in mind is that when subjected to force, either heat or pressure, the metal bellows allows the expansion joint to bend rather than break.

Why metal?

Metal expansion joints are, simply put, stronger than the alternatives (plastic, ceramics, etc). They are also easier to shape (although metal bellows are relatively intensive to create).

They are also more capable of coping with extremes of temperature, as they themselves can expand and contract without sustaining the weathering damage that hard plastic would. There are rubber versions available, but their use is strictly limited, and in any situations involving heat, for example, they are impractical.

Heat-tolerant bellows and expansion joints can be made from a variety of metal alloys, such as steel, titanium, and many others according to the specifications of the job in hand. Often, a custom-made alloy can be designed to meet a job's requirements.

What specific applications are there for this technology?

The central purpose for metal bellows is in fluid management. This, however, finds use in a great many things. Expansion joint solutions have been employed in industries and technologies such as altitude sensors, piping for industrial coolant, the petrochemical industry, applications involving steam, the nuclear power industry, medical technology, waste management, and some automotive engines and pump systems.

What kind of tolerances can be built into it?

A metal bellows can be designed to cope with a wide variety of different stresses and pressures. The three main types of movement are referred to as lateral, axial and angular.

Lateral is a movement of the two ends of the joint where those ends stay parallel to each other. Axial is either the stretching or flattening of the expansion joint along its length. Angular movement is simply the curving round of the joint along its axis. At present, expansion joints can be designed to cope with any of these three specific stress types.

The one type of movement they cannot deal with, however, is torsion, namely twisting along the piece's length. This is best avoided by keeping the joint fastened in place by external attachments, and taking care with the fastening when attaching it in the first place.

How much heat can a metal bellows withstand?

This varies greatly depending upon a variety of factors; the alloy chosen, whether or not any anti-corrosives are added, the design of the bellows itself, and whether it was welded or shaped. There are certain practical solutions and physical limits, but as long as the heat is foreseen, joint solutions can usually be found.