Axial Expansion Joint 1

[B.L.Smith]

Hi

As I know and EJMA mentions, axial expansion joints should not use in lines with offset. But In some projects I saw this kind of installation for axial expansion joints. Am I wrong in understanding of EJs installation?

 

[C2it]

You would have to be more specific about your understanding.

That said, the words 'expansion joint' and 'offset' are enough to send a chill down the spine of every older generation piping engineer. It is precisely the cause of the Flixborough disaster which killed (I think) 29 persons on site and destroyed and entire chemical complex.

As I recommended on another post today, just google 'Flixborough' for some sobering facts.

 

[B.L.Smith]

Thanks C2it
See attached file. In the attached file there is a rubber expansion joint with limit rods(axial expansion joint) that is installed in a line with a offset or similar installation. But as we know this installation is not correct. What is the reason for the installation?

 

[C2it]

Brad,

The installation is clearly low pressure, probably water. The pump type is not susceptible to misalignment due to pipe loads and if it's water, there will be no expansion problems.

It is common in water applications to place a rubber joint such as shown (usually with tie-bars) on pumps to limit noise transmission and to allow for a certain amount of misalignment.

 

[B.L.Smith]

Is it a lateral rubber EJ(tied rods)?

 

[C2it]

The EJ on the pump nozzle looks long enough to have some lateral capacity, but the geometry and support pretty well guarantees that there will be negigable lateral movement, other than any installation inaccuracy.

Actual allowed lateral movement would be available from the vendor.