Metal Expansion Joint

More Information

Keyser Metal Expansion Joints Applications For Axial Movement Material Evaluation For Hydro-Forming Process Types of Expansion Joints available Pressure Balanced Expansion Joints Dual-flex And Universal Series Model PBEU Analysis i) Universal LPG Expansion Bellow ii) Sleeve Type Expansion Joint

Pressure Balanced Expansion Joint

Keyser Pressure Balanced Expansion Joints are pressure balanced elbow or tee expansion joint systems specifically designed to overcome the reaction load caused by internal pressure acting, against turbine casings, pumps and other equipments. In situations where a main anchor cannot be installed to absorb axial and lateral motion, pressure balanced expansion joints are installed.

Keyser Pressure Balanced Expansion Joint design uses flow and balancing bellows inter-connected by using tie rods. The balancing bellows are subjected to the same line pressure as the flow bellows. When the flow bellow pressurizes, the tie rods extends the balancing bellows by an equal amount. There is no change in the volume, thus the pressure force remain in balance. Do note that there is no volume change when the flow bellows deflect laterally. The balancing bellows need only to contain the proper number of convolutions required to absorb the axial movements of the system. The axial force, however, is the total of the force required to move the line bellows and balancing bellows.

Key Features:

• Absorbs axial and lateral movements while restraining pressure thrust
• Eliminates main anchors
• Minimum guiding required

How Does Keyser's Axial Pressure Balance Work

Internal pressure that have been built up causes a pressure thrust on flow bellows (A) and against the side outlet (elbow or tee) (C). This thrust is balanced by the identical internal pressure thrust (G) pushing on balancing bellows (B) that is transmitted back through the tie rods (D) counteracting the line pressure thrust (F). The force remaining is the axial spring force required to compress line bellows (A) and extend balancing bellows (B), plus whatever friction load is generated by the piping moving through the alignment guides.

Applications
Keyser Pressure Balanced Expansion Joints are used when there is a change in the direction of the pipe line, and most commonly used is adjacent to equipment such as pump or valves where allowable nozzle loads necessitate the elimination of pressure thrust.