Whether the operating load of spring which is closer to valve should be
lesser than the valve weight acting downwards
=> I mean to say that there should not be a large difference between
these two forces say valve weight is 2 tonne & spring force acting upward
is 8 tonne this will cause huge
forces & moments on the valve flange especially when the geometry is like
spring---spool piece---valve immediately connecting to the header of
higher size through RF pad connection.
Regards,
Rajesh V Balapure
|---------+---------------------------->
| | <baskaran@idealtd|
| | .com> |
| | |
| | 02/25/2005 10:16 |
| | AM |
| | Please respond to|
| | PipingDesign |
| | |
|---------+----------------------------> >-------------------------------------------------------------------------------\ --------------------------------|
|
|
| To: <Rajesh.Balapure@ril.com>, <PipingDesign@yahoogroups.com> |
| cc: (bcc: Rajesh V Balapure/JAMNAGAR/RIL) |
| Subject: RE: [PipingDesign] Digest Number 1424 |
| Importance: Normal Sender's OU: Reliance |------------------| | | | [ ] Confidential | | | |------------------||
>-------------------------------------------------------------------------------\ --------------------------------|
Dear Mr.Rajesh,
as you said correctly the if the forces & moments at the valve flanges is less then it will be easy for dismantling the valves in operating condition.
i need some clarification on your point to design the spring suitably near the valve
In general we have to locate the supports closer to the concentrated mass like valves...
Whether the operating load of spring which is closer to valve should be lesser than the valve weight acting downwards
regards,
A.R.Baskaran
Message: 13
Date: Thu, 24 Feb 2005 21:02:03 +0530 From: <a href="/group/PipingDesign/post?postID=BbjmzaLPBqQMOOB3eTlHDgFjHlQG_ZAcYaelqKMABH20Fw8rSIxVNpI60HtlDDqeEP07V8UB-b5YY_DP88c">Rajesh.Balapure@ril.com</a> Subject: Re: Regarding Piping Stress Analysis
If Forces & moments at valve flanges are less,it helps for the easy
removal of the valve in operating position.
For e.g. Any springs are located nearby valve ,the cold loads if higher may
introduce some forces & moments on the valve flange ,which may cause the
difficulty if that valve is leaking & want to replace the gasket .
The spring force acting (say upward)on the valve flange can cause the
shearing of studs(valve weight acting downward) resulting in locking of the
bolt removal which may need the heavy force to be applied at that existing
position.
To avoid such a position ,spring's, if located close to valve are to be
designed so that it will not transfer heavy forces & moments to the valve
flange.
The allowable forces & moments at valve flange may be for the abovesaid
purpose.
Regards,
Rajesh V Balapure
----- Forwarded by Rajesh V Balapure/JAMNAGAR/RIL on 02/24/2005 08:49 PM ----- |---------+---------------------------->|
| | Rajesh.Balapure@r|
| | il.com |
| | |
| | 02/24/2005 08:25 |
| | PM |
| | Please respond to|
| | PipingDesign |
| | |
|---------+----------------------------> >-------------------------------------------------------------------------------\ --------------------------------| | | | To: <a href="/group/PipingDesign/post?postID=Te1tCSM8Jck5-Xjw9sHUZmAts-aM-nYngp1nWk_3CBGnatZbndGZz7krOE1pGfFi4IRFz8Dp3xuytKKMP2YB8tkdsvfgV7Q">PipingDesign@yahoogroups.com</a> | | cc: (bcc: Rajesh V Balapure/JAMNAGAR/RIL) | | Subject: Re: [PipingDesign] Regarding Piping Stress Analysis | | Importance: Normal Sender's OU: Reliance |------------------| | | | [ ] Confidential | | | |------------------|
>-------------------------------------------------------------------------------\ --------------------------------|
What you did is correct ,but What did you mean by allowable forces &
moments for valve?
Vendor might want you to check allowable forces & moments for flange
leakage analysis point of view.
The Allowable nozzle loads may affect in case the valve weight is different
from earlier??
Also you have not mentioned the pipie size & valve size ??higher sizes
critical lines requires flange leakage analysis.
Regards,
Rajesh V Balapure
|---------+---------------------------->|
| | sathish babu |
| | <togsb@yahoo.co.i|
| | n> |
| | |
| | 02/24/2005 10:22 |
| | AM |
| | Please respond to|
| | PipingDesign |
| | |
|---------+----------------------------> >-------------------------------------------------------------------------------\ --------------------------------| | | | To: <a href="/group/PipingDesign/post?postID=Te1tCSM8Jck5-Xjw9sHUZmAts-aM-nYngp1nWk_3CBGnatZbndGZz7krOE1pGfFi4IRFz8Dp3xuytKKMP2YB8tkdsvfgV7Q">PipingDesign@yahoogroups.com</a> | | cc: (bcc: Rajesh V Balapure/JAMNAGAR/RIL) | | Subject: [PipingDesign] Regarding Piping Stress Analysis | | Importance: Normal Sender's OU: Reliance |------------------| | | | [ ] Confidential | | | |------------------|
>-------------------------------------------------------------------------------\
--------------------------------|
Hello Everybody,
I will introduce myself to the group, i am
sathish babu working in ASLTOM Projects india
Ltd in piping department of plant engineering
section.
I am a Graduate Engineer and having a experience of three and Half Years.
Now i am working in CAESAR II stress analysis
When a Forces and moments to be checked ? to my Idea i usually check on Equipment Nozzles where the piping is to be connected for that i will be defining the nozzle node to have displacement and check in the Restraints Summary for all operating and sustained condition.
Now i faced a small problem , i have angle valve ( Main steam bypass valve dumped to condenser ) while doing analysis i have defined it as rigid component and finished the analysis.
After that the valve manufacturer produced the drawing and asked me to check the allowable forces and moments on the valve.
What i did was went to local element forces and moments and checked the allowable forces and moments on the corresponding node to be OK - Whether This is Right or I have to do anything more
If anyone have any Idea about when this forces and mon=ments to be checked and the basis please explain
Thanking you
Sathish Babu
Steve McKenzie <mechproj@xtra.co.nz> wrote:
Paul
I have already given myself a stern warning about this, and any further outbursts on my part will, regrettably result in me requesting my resignation. This has been conveyed to me in a formal letter as a first and final warning, so I will not accept any excuses from myself. Sometimes I hate being my own boss.
It sure would be nice to leave this whole national/language mess alone.
If you agree please indicate by not replying.
Cheers
Steve
-----Original Message-----
From: Paul Bowers [mailto:pbowers@pipingdesign.com]
Sent: Thursday, February 24, 2005 3:58 PM
To: <a href="/group/PipingDesign/post?postID=Te1tCSM8Jck5-Xjw9sHUZmAts-aM-nYngp1nWk_3CBGnatZbndGZz7krOE1pGfFi4IRFz8Dp3xuytKKMP2YB8tkdsvfgV7Q">PipingDesign@yahoogroups.com</a>
Subject: Re: [PipingDesign] Metallized valve
Sajit Viswan wrote:
> Paul, > > I haven't understood your giberrish. Didn't bother to > try to understand either. > > Sajit
Maybe all the recent discussion has served to bring out unsaid, possibly
pent-up thoughts and attitudes - it wasn't planned to do so.
I remind everyone that you are all free to unsubscribe at any time.
This discussion list is at about 1100 members now; well over 75% do not ever contribute to the technical discussion. I don't think that 750 sudden unsubscriptions would hurt the quality of the technical discussion.
Then again, it seems to be a free-for-all at the moment and the best move might be to just let it play itself out without possibly heavy-handed intervention.
Paul
<a href="http://www.pipingoffice.us/">http://www.pipingoffice.us/</a> =========================================Main site: <a href="http://www.pipingdesign.com">http://www.pipingdesign.com</a>
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Groups Links [Non-text portions of this message have been removed] ________________________________________________________________________ ________________________________________________________________________ Message: 14 Date: Thu, 24 Feb 2005 11:29:55 -0600 From: Christopher Wright <chrisw@skypoint.com> Subject: Re: Regarding Piping Stress Analysis On Feb 23, 2005, at 10:52 PM, sathish babu wrote: > When a Forces and moments to be checked ? The short answer is 'always.' Piping system stress must be kept within code limits for all loadings and all service conditions. Verification that you have not exceeded code limits is your responsibility as an engineer. You need not always do a complete stress analysis of every last detail, but you must be able to satisfy yourself, using judgement based on experience, that all the details will meet the code. CAESAR isn't enough by itself, because it provides results based on idealizations with limited validity. In your case you idealized the valve as rigid, which it is with respect to the piping network, but the valve body isn't absolutely rigid. Loads applied to the valve cause deformations and stresses which must also meet code requirements. Normally design of the valve is the responsibility of the valve manufacturer, but the manufacturer can't possibly anticipate every possible service condition the valve might see, and it sounds like he asked you for an assessment of the valve under your particular service. Did I guess right? If so, do you have reason to believe that your service is such that the valve body might be over-stressed? Again, guessing, I suspect that what you call 'allowable moments' are in fact calculated moments from CAESAR which turn out to be allowable because they don't exceed the maximums allowed by the code for your loading. In that case they'd be allowable moments for the pipe, but not necessarily allowable moments for the valve. To know that you'd need to do a stress analysis of the valve body. Presumably that's why the manufacturer 'produced the drawing,' by which I presume that he produced a drawing of the valve body. In fact you should probably be asking the manufacturer for guidance, and be prepared to help out the some extent, at least with an estimate of valve body stress caused by your particular combination of forces and moments. Doing a complete job of it may be beyond your scope of work, because it could be expensive, but you may have to do something if you want to use that particular valve. This is your piping system, not the valve manufacturer's, so you have the major responsibility and interest for insuring that the valve provides satisfactory service. The valve manufacturer's customer support should be willing to help to a degree--if he isn't interested in helping, maybe it's time to tell him you're shopping elsewhere for valves. (As an aside, here's one of those engineering issues which demands accurate written communication, whether in English or Hindi or whatever. You can't do it with a picture. I've guessed at a lot of the issues Satish is facing, and I may have gotten it totally wrong. Satish's English is good, and what I said is correct, but I might not have answered the question or my answer might be the answer to the question as posed, but the question posed might not be the question he meant to ask. Or it might be the question he meant to ask but not the question he should have asked so that I might infer the intended question and thus give him the answer he needed, which of course might not be the answer he expected. That's perfectly clear, isn't it? ;->) Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=EylZFcV5byFDYyBHwVJNnjdoo97lEzpCqkCVw5fYzqZVjBufnyDNJtW6AKcO22CWrkfXXvZUfhr9cWfaw9M">chrisw@skypoint.com</a> | this distance" (last words of Gen. .......................................| John Sedgwick, Spotsylvania 1864) <a href="http://www.skypoint.com/~chrisw/">http://www.skypoint.com/~chrisw/</a> ________________________________________________________________________ ________________________________________________________________________ ========================================= PipingOffice - Excel Spreadsheets for Piping Calculations <a href="http://www.pipingoffice.us/">http://www.pipingoffice.us/</a> ========================================= Main site: <a href="http://www.pipingdesign.com">http://www.pipingdesign.com</a> ------------------------------------------------------------------------ Yahoo! Groups Links ------------------------------------------------------------------------ ========================================= PipingOffice - Excel Spreadsheets for Piping Calculations <a href="http://www.pipingoffice.us/">http://www.pipingoffice.us/</a> ========================================= Main site: <a href="http://www.pipingdesign.com">http://www.pipingdesign.com</a> Yahoo! Groups Links [Non-text portions of this message have been removed]Received on Fri Feb 25 04:33:00 2005
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