#74121 - 11/08/19 09:25 AM
Gimbal Expansion joints Arrangement
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Member
Registered: 01/31/12
Posts: 68
Loc: Malaysia
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Dear Friends, I'm working on a ducting system with a design temperature 500C and OD 1400mm that is an inlet of equipment with a diameter of 17m and an average temperature of 550-600C. I have designed this line with 2 gimbal expansion joints as attached file. Is it a correct design? Is this system well-arranged for absorbing the radial movement of equipment and absorbing the vertical movement of the duct(22m vertical line)? Do two expansion joints withstand 7m spool between them? Regards,
Attachments
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The shortest answer is doing
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#74122 - 11/08/19 11:46 PM
Re: Gimbal Expansion joints Arrangement
[Re: NRAM]
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Member
Registered: 10/22/06
Posts: 38
Loc:
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1. If possible orient horizontal leg perpendicular (appears at 45 Deg to me) to nozzle axis to absorb radial movement from nozzle and vertical expansion. 2. I hope you have started with simple EJ such as tied universal etc. prior to using 2 Gimbal EJ's 3. For the 7m spool between EJ's, you may provide a spring support. 4. What are the restraints in the vicinity of EJ?
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#74123 - 11/09/19 02:03 AM
Re: Gimbal Expansion joints Arrangement
[Re: Sigma]
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Member
Registered: 01/31/12
Posts: 68
Loc: Malaysia
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Dear Sigma, Thanks for your reply. 1-The equipment is installed in the field and I cannot change the orientation of the nozzle. 2- WIth using tied universal EJ, moments on the expansion joint is about 10 and 9 ton.m in My and Mz. Is it Ok for the Universal EJ? (It should be mentioned that overall lateral movement of expansion joint due to equipment and vertical line movement is 200mm) 3- Is it reasonable to report loads on two gimbal expansion joints to the EJs' vendor? 4- Spring support with guide support.
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#74126 - 11/11/19 03:53 AM
Re: Gimbal Expansion joints Arrangement
[Re: NRAM]
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Member
Registered: 10/22/06
Posts: 38
Loc:
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If the radial expansion is relatively smaller(<<< vertical), then in present 45deg configuration, I believe the 2-Gimbal EJ arrangement can absorb radial expansion from the equipment, although somewhat less effective than had the horizontal spool oriented 90deg to nozzle axis. Are Caesar-II results any different? 200mm of lateral movement would result in ~1.64 Deg of rotation for each bellow (with 7m pipe spool in between) and should not be an issue to EJ vendor. Please show restraints local to EJ in the datasheet (a small sketch for better understanding), so that the EJ vendor can review the adequacy of supports.
And yes, those external piping loads (over and above the pressure thrust loads) should be sent to EJ vendor for proper design of external hardware.
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#74145 - 11/13/19 02:59 AM
Re: Gimbal Expansion joints Arrangement
[Re: NRAM]
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Member
Registered: 10/22/06
Posts: 38
Loc:
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IMHO three Gimbal EJs in series would be too much and would not be stable arrangement. Better discuss with seniors/EJ supplier.
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#74146 - 11/13/19 07:01 AM
Re: Gimbal Expansion joints Arrangement
[Re: NRAM]
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Member
Registered: 10/22/06
Posts: 38
Loc:
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Further to add. Are you sure about use of Simple(fabric) EJ-1 at Line temperature of 500 DegC you mentioned above???
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#74153 - 11/13/19 04:30 PM
Re: Gimbal Expansion joints Arrangement
[Re: NRAM]
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Member
Registered: 01/29/10
Posts: 1025
Loc: Louisiana, US
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3 joints in a row is possible (here's a diagram, but with ball joints). https://www.hyspan.com/BarcoBall.htmlHowever, you have to have a system that's protected from the effects of gravity causing the segments between joints from slumping over. In the diagram on the site, you should assume that the pipe is in the horizontal, and that the hole thing is universally supported, and that the make-up the ball joints perform is exclusively in the horizontal plane.
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#74424 - 02/08/20 12:21 PM
Re: Gimbal Expansion joints Arrangement
[Re: NRAM]
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Member
Registered: 01/11/04
Posts: 383
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Old posting but couple comments.
All three proposals have one common problem. Not enough space for the ancillaries. In some cases can be solved by high expense. 500 C is quite high temperature and normally floating ring designs are required.
As a general comment. Most pipe designers give insufficient space for the expansion joints. Add to that unnecessarily low spring rates, wrong movements... Pipe designers should realize that bellows element goes often well past the yield point and it has impact on force directions.
One of the biggest mistakes with the movement specification is to give equal movement in two directions. Lets assume the 500 C case. CAESAR II gives compression 50 mm and the stress engineer specifies 50/-50 mm movement for the expansion joint. Big mistake. 50 mm compression is a result of 480 C temperature difference. To have 50 mm expansion the pipe temperature should go to about -460 C. Expansion joint can be designed for these movements but it is less safe compared to the one where movements are specified correctly.
Just to remind again: Expansion joint with tie rods cannot have axial movement.
I have designed expansion joints well over 20 years, try to train engineers and have special design software and I battle with these issues every day - world wide.
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Regards,
Jouko jouko@jat.co.za
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