This pipe expansion joint is simply a bellows element with end connections. Regardless of accessories, such as liners and covers, it will deflect in any direction or plane that the bellows will. It is the least expensive type, but requires that the piping be controlled as to the direction of the movements required of the unit. The pipe expansion joint should not be expected to control the movement of the pipe. If the piping analysis shows that the pipe expansion joint must accept axial compression, then the piping must be guided and constrained so that only that movement will occur.

This expansion joint will not resist any deflections with any force other than the resistance of the bellows, which is a function of the spring rate times the deflection amount. It is incapable of resisting the pressure thrust along its axis, which is the product of the pressure times the effective, or cross sectional, area of the bellows. Large diameter units, even with low pressures, can generate very large axial pressure thrust forces, which must be reacted by main and directional anchors. Otherwise the expansion joint will extend with disastrous result

Metal Bellows Expansion Joint with hydroformed bellows for minimal residual stresses

The Model MN metal bellows expansion joint uses a hydroformed bellows for minimal residual stresses and minimal thinning at the convolution root and crown. It is an excellent choice for any application requiring a metal bellows expansion joint within the pressure ratings of the 150 and 50 psi

Metal bellows expansion joint provides perfect balance between value and performance

The MNLC metal bellows expansion joint provides the perfect balance between value and performance. With two standard lengths and three pressure ratings available, can be delivered quickly. Non-standard designs are also easily available.

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PROTEC is a privately owned company established in Doha, Qatar engaged in the fields of Engineering, Supply, Construction, Installation, Commissioning, Operation and Maintenance of various types of equipment for the Water, Waste Water, Energy, and Industrial markets.


Head Quarters: Middle East,
Africa & CIS

: (+974) 44 16 93 25
: (+974) 44 32 39 77
: (+974) 44 16 94 36