Nirmal,
It's quite clear now.
In my opinion, u need not to fear about the differential pr. acting on the gasket due to the different matl. on both the sides.
It will be of minor nature and gasket compresability will take care of it. However u can analyse the piping in caesar. Make sure u are not placinn any support that will force the piping displacement to take place towards the vessel nozzle.
Hope this clarifies ur doubt.
Tushar Zope
Piping Engineer
Foster Wheeler Eastern Pte. Ltd, Singapore
Ph: 6890 0774 Fax: 6223 2989
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____________________Reply Separator____________________Subject: Re: (PipingDesign) Re:(PipingDesign) Flanged connections wit Author: "NIRMAL MURARKA" <SMTP:Nirmal-Murarka@enc.ltindia.com> Date: 7/4/02 12:23 AM
Tushar,
Equipment MOC and PIPING MOC difference is because of cladding in the
equipment for cost optimization.
Following are the details for this case: Equipment: 2-1/4Cr-1Mo with SS347 cladding. (Heat Exchanger) Eq Nozzle: 1500# RTJ, 2-1/4Cr-1Mo with SS347 cladding. Service: Diesel / Kerosene, 400deg C, 125 Kg/Cm2 Piping : 1500# RTJ, SS321
Yes, as you said in this case also the equipment flange is of higher rating w.r.t the piping. But in such a case the piping has to take a off the spec flange the match the equipment flange. That's not a problem. In such a case if the piping flange is to be made to suit the MOC of eq flange, the sch/thickness of this flange will still be made to suit the piping thickness. Hence there is not problem for pressure drop or turbulence also.
The problem, I fear, will be the RTJ gasket getting differential pressure because of different MOC of either side flange for case # 1. And the difficulties with the case # 2 are as explained in your mail - stress intensification and welding!
Nirmal Murarka
Baroda
India
"Tushar, Zope "
<zope_tushar@fwc. To:
<PipingDesign@yahoogroups.com>
com> cc:
Subject: [PipingDesign]
Re:(PipingDesign) Flanged
04/07/2002 06:33 connections with dissimilar
Materi
PM
Please respond to
PipingDesign
Nirmal,
Please clarify the design conditions of vessels & piping and the fluid
being
handled.
Dissimilar weld are not prefered. And I think this is very rare case that
the
piping matl & vessel matl are different. They both handle the same fluid
and
will have same operating conditions. Some consultants do have higher flange
rating for nozzles.
Either of the flange joint or the weld joint will not avoid the unequal
(vertical) thermal expansion.
Proper installation / tightening of flange joint avoids the possibility of
leakage. The dissimillar weld in fact will be the place of stress
intesification. The thickness may be different at this weld. This will
create
more pr. drop & turbulance and to avoid this a inside tapered peace of
(higher
quality material) with thk matching on either side shall be used.
Hence if the vessel spec says that nozzle is flanged then go for option 2.
Tushar Zope
Piping Engineer
Foster Wheeler Eastern Pte. Ltd, Singapore
Ph: 6890 0774 Fax: 6223 2989
Disclaimer
'The information contained in this email and the files transmitted with it
are
confidential and intended only for the use of the individual or entity to
whom
they are addressed. If you have received this message in error, please
immediately notify the sender and delete the mail. The views or opinions
presented in this email are those of the author and do not necessarily
represent
those of the company. The recipient should check this email and any
attachments
for the presence of viruses. Foster Wheeler Eastern Pte Ltd accepts no
liability
for any damage caused by any virus transmitted by this email.'
____________________Reply Separator____________________Subject: (PipingDesign) Flanged connections with dissimilar Materials Author: "NIRMAL MURARKA" <SMTP:Nirmal-Murarka@enc.ltindia.com> Date: 7/3/02 8:25 AM
For a spec break with change in material near a flanged joint (may be equipment flange and piping flange) what should be the correct approach:
May be temperature and type of materials will play a key role. When can we go with option # 2 safely ?
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Received on Thu Jul 04 14:50:00 2002
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