Expansion bellows

Bellows are used in tubular heat exchangers and piping systems to compensate for thermal stresses and strains. Bellows are also useful for compensating the effect of frequent pressure variations.

Thermal strains develop in connection to variations in temperature and thermal stresses develop in connection to

• When the tubes and the shell in a tubular heat exchanger are exposed to different temperature increases during service and/or when they are manufactured in materials with different thermal elongation coefficients.
• When tubes in a tube system are exposed to an increased temperature, the tubes will elongate and this elongation causes a thermal stress.
• Cyclic temperature variations, which cause fatigue damages and/or corrosion fatigue damages in heat exchangers.

Siljan Allards has special equipment and tools available for the manufacturing of bellows.
The bellows can be made in carbon steel, stainless steel or a nickel base alloy.

The size range is from shell or tube diameter of 100 mm and up to ca 3000 mm. Single, double and triple bellows can be manufactured.

We design the bellows according to EN 13445 (European Pressure Vessel Code) or any other standard, considering the number of thermal cycles during the life time of the equipment and also considering the stress levels. Heat treatment is performed according to rules.

The bellows are delivered with complete documentation.