Positioning of Fixed and Sliding Saddles for a Horizontal Shell & Tube Heat Exchanger 3

[DK44]

I would like to know, what is the basis of positioning the Fixed and Sliding saddles(which side which saddle) for a horizontal Shell & Tube Heat Exchanger.

 

[SnTMan]

DK44, normally you would locate the fixed support at the end of the exchanger having the most process nozzles. For a multipass tubeside arrangement this will nearly always be at the inlet channel end. For single pass tubeside arrangements it is less clear.

Ideally the buyer will either specify or review and confirm, since typically only the buyer has any knowledge of the arrangement of the attached piping.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Christine74]

It really depends on how the attached piping is configured but generally you want the sliding/slotted saddle support located at the front (channel) end of the exchanger. This is because the piping that's attached to the exchanger is typically anchored beyond the back end of the exchanger, so when the equipment heats up the thermal displacement for both the exchanger and the attached piping will be in the same direction, thereby producing less stress than if they thermal displaced in opposite directions.

-Christine

 

[SnTMan]

Christine74, kind of opposite my experience, but illustrates my point about only the buyer knowing

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Christine74]

Oh I agree, probably 90% of heat exchangers out there are anchored incorrectly with the fixed support near the front channel. This is probably due to the fact that 1) the location of the the slotted saddle support usually isn't specified by the buyer, and 2) the piping engineer didn't review the exchanger G.A. drawing or he/she just assumed that there must be a good reason why the manufacturer chose to use the front saddle support as the anchor point.

-Christine

 

[SnTMan]

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

One reason is: For units with removable tube bundles, supports should be designed to withstand a pulling
force equal to 1-112 times the weight of the tube bundle.

Regards
r6155

 

[r6155]

Sorry, I said "....force equal to 1-1/2 times the weight of the tube bundle".
See TEMA

Regards
r6155