BOA Group - Expansion Joints, Metal Bellows, Rubber Bellows and Metal Hoses

The BOA Group, with its subsidiaries and shareholdings, is one of the world's leading manufacturers of flexible mechanical elements. The company designs, manufactures and distributes steel and rubber expansion joints, bellows and hoses worldwide.

Amongst others, BOA's markets are energy, petrochemical, pharmaceutical, aerospace, shipping, instrumentation and automotive.

With about 20 subsidiaries in eleven countries and many more sales service offices the BOA Group is represented around the world. BOA has manufacturing plants in Germany, Switzerland, France, Poland, the US, China and Brazil.

Customised engineering solutions

In the industrial division, the BOA Group manufactures expansion joints, bellows and metal hoses for applications in energy technology, construction, ship building and petrochemical plants.

Solutions include both standard and customised products. Often products are developed and designed together with the customer. Quality is always the top priority and BOA has had an unparalleled reputation for over 100 years.

Expansion joints, rubber bellows and metal hoses for energy applications

In almost every energy application flexible solutions of the BOA Group can be found. For generating electricity or heat BOA expansion joints, rubber bellows and metal hoses are used in a wide variety of applications. Applications include:

• Expansion joints for critical applications in nuclear power plants
• Expansion joints for general piping applications in all types of power stations
• Special bellows for applications in solar power stations
• Stainless-steel bellows and expansion joints for high-voltage switchgear and transformers
• Bellows for critical valve seal applications
• Stainless-steel hoses and expansion joints for gas turbines
• Bellows for heat exchangers

These are just a few examples where our innovative solutions can be found. With our engineering facilities, global manufacturing locations and unrivalled experience, we can offer solutions for any energy application.

Expansion joints

Expansion joints are flexible piping elements used for taking up movements in piping systems. These movements can be caused by thermal expansion, ground movements or misalignment.

BOA has 100 years of experience in the application of expansion joints in power stations and other energy plants including nuclear, CCGT, CHP and solar. BOA manufactures all types of expansion joints, including axial, lateral, hinged, angular and pressure balanced.

BOA's worldwide manufacturing capabilities can produce expansion joints up to 4m diameter and up to 35t in weight. They can also be made from other alloys such as Inconel, Incolloy and Hastelloy.

Rubber bellows

BOA's rubber expansion joints find uses such as vibration absorbers, flexible connections to pumps, or other rotating equipment. BOA rubber expansion joints are fully approved for applications in nuclear power plants in Germany. They have also been applied successfully in piping systems for water, gases and different chemicals and are often found on large diesel and gas engines. BOA rubber bellows can be manufactured up to 3.5m in diameter and are supplied complete with flanges and other hardware such as tie bars and sleeves.

Metal hoses

Stainless-steel flexible hoses offer a wide range of solutions to different problems:

• To take up misalignment or thermal expansion
• To absorb vibrations or to facilitate repeating movements

BOA manufactures mechanical and hydraulically formed hose with either annular or helical corrugations. Usually made from AISI 316L stainless steel, they can also be manufactured from other alloys.

When fitted with stainless-steel braiding these hoses can withstand working pressures up to 350 bar.