Externally pressurised expansion joints is the perfect solution when axial movements and pressure is high.
Bellows elements of externally pressurised expansion joints are arranged so that the media ﬂow is on the external side of the bellows, while the inside part of the bellows is only subjected to atmospheric pressure with this side being in direct connection with the atmosphere.
External pressurising of the bellows eliminates column instability as a design limitation while permitting the absorption of large axial movement. While an internally pressurised bellows will become unstable and buckle due to internal pressure, pressure around an externally pressurised bellows will have a stabilising effect on the bellows. This makes it possible to achieve a construction of externally pressurised expansion joints with great ﬂexibility for large axial compensation. With only the outside of the bellows subjected to pressure and the convolutions packed under a cover, the perfect conditions for external insulation or underground installation can be achieved.
As the convolutions of externally pressurised expansion joints are well protected under a cover, transport damage to the convolutions is unlikely to occur but most importantly, the cover offers maximum protection against leaking bellows or bellows failure.
25 – 1000
304, 316, 321
Carbon Steel, Stainless Steel
Please consult with our technical department for different working conditions and design parameters.