BOA Multi -Ply Engine Exhaust Expansion Joints
The BOA Multi-Ply Bellows Design
BOA pioneered the development of the unique multi-ply bellows design which proved to be exceptionally effective in absorbing thermal expansion and vibration in engine and compressor piping systems.
The BOA Multi-Ply Bellows is manufactured from a laminated tube which consists of thin gauge stainless steel plies. This tubular body is formed into corrugations by means of a unique manufacturing process which assures exacting dimensions of the bellows geometry.
Advantages of BOA’s Multi-Ply Bellows
Flexibility- The use of thin gauge material in the manufacture of the multi-ply bellows combined with a greater number of corrugations per unit length increases the flexibility and reduces the deflection forces due to movement.
Lower Thrust Forces-Depending on the operating pressure the end forces acting on anchors or engines may be substantial. BOA’s favorable corrugation profile and low spring forces reduce the end forces thereby improving engine and turbocharger efficiency.
Longer Cycle Life– The contour of the thin gauge multi-ply convolution is designed to keep pressure induced and deflection
stresses at a minimum. As a result of the low stress level that the bellows experiences during operation, cyclic endurance is substantially improved.
Cycle Life Curve
BOA Engine Exhaust Expansion Joints are designed for 5000 cycles at full rated travel for all series shown in the tables. The graph below allows for the conversion of decreased travel requirements to increased cycle life.
To ensure optimum bellows design and cycle life requirements the actual exhaust system movement conditions must be specified. Once the system movement conditions have been identified an expansion joint may be selected that dramatically increases cycle life.