Stainless Steel Pipe Expansion 2

[Lan123]

What is the best way to allow a 1.5 inch movement (Axial only) due the temperature difference for a 36 inch 316L stainless steel pipe (convey hot air) through a vertical wall of building. The pipe is anchored inside the building but I am trying to permit a 1.5 inch free axial movement for the pipe at the location where the pipe penetrates the vertical wall and leaves the building. The pipe is located in a cold climate. My intent is to transfer a minimum horizontal force to the vertical wall.

Thanks in advance.

 

[C2it]

Unless you have lots of space and a suitable geometry, I suspect that a loop or similar shape to absorb expansion will not be practical.

An expansion joint (or preferably a pair of) would be a good option. It is always best to avoid a simple axial bellows if possible due to the pressure thrust, assuming you have some pressure to deal with. A pressure compensating joint could be an option, albeit an expensive one.

I would recommend using two hinged joints or possible a double-tied expansion joint, both options located in a leg of pipe perpendicular to the movement.

 

[LittleInch]

A simple sliding bellows arrangement like this one

http://www.usbellows.com/products/slip_type_compensators.htm

will probably suffice, especially if your product is at relatively low pressure. These type typically have low forces, but search on "sliding pipe bellows" or "expansion joints" and talk to a couple of vendors about our particular requirements

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[bimr]

What about just an open sleeve through the wall. Size sleeve large enough to allow for movement due to expansion and contraction Install flashing around the sleeve to prevent the weather from entering, but don't attach the flashing to the pipe.

The blower room is not conditioned space so a tight seal is not necessary.

 

[C2it]

Little Inch ... beware of axial forces (due to pressure), which Lan123 wants to minimise.

10psi internal pressure in your simple sleeve equates to around an axial 10,000 lbf at the wall / anchor.

Remember Flixborough !

 

[LittleInch]

All depends on the actual pipe arrangement and what is fixed and what is moving. On a simple level if you fix a sleeve into the wall, but then have one or two sliding elements either side of your fixed tube, there is very little axial thrust on the wall. Of course you get thrust somewhere else on the pipe which you need to control, but you can't have everything and the OP did say the pipe is snchored inside the building.

There are sleeve and seal arrangements which allow axial movement of a solid continuous pipe through an opening whilst providing some sort of seal - all depends on temperature of the pipe, amount of rain / snow etc it has to resist. 1/1/2" is not that big a movement. A schematic drawing would help, but it's not a complicated question.

I do remember flixborough and looked up the root causes which may have been bellows related. Any system needs to be correctly designed or it has severe consequences.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Lan123]

All ,

Thanks a lot for all the replies.

C2it you are correct. Minimal transfer of forces to the vertical wall. The internal pressure in the pipe is about 11 psi.

I like what bmir proposed. I will do more research on this. I will also contact USbellows.

Regrads

 

[racookpe1978]

Ah!

But a "simple sliding joint" can lock up (freeze) by rust, debris, birds and dirt, ice or dirt (dust probably won't affect it much) and possibly galling if stainless. Not too likely.

A well-kept-up, maintained slide and cover assembly routinely greased and with a good animal/critter/bug and bee cover can last a long time though. Or until the maintenance foreman leaves and a skinflint plant manager decides to cut costs and eliminate maintenance ... Then the wall joint doesn't slide. It still moves 1.5 inch sideways, it just doesn't slide.

I would have expected less resistance to an in-line bellows installation, but it appears there is an institutional memory against them.

 

[C2it]

Racookpe .... I have nothing against in-line EXJ's, provided the inevitable axial thrust is properly designed for. Unless you can afford a pressure compensating device of course. Kerching !