From: On Behalf Of yogesh modak
Sent: Thursday, September 04, 2008 1:26 PM
Subject:Copper gasket.
Thanks for your mail.
Will go through the tables and other material mentioned by you.
However another query regarding mechanical properties of copper under compression. Can we use standard bolting torques while using copper gasket?
Any informatino on mechanical properties of Spiral wound gaskets?
thanks & regards
yogesh
----- Original Message ----
From: "Bhattacharyya_
Sent: Thursday, September 4, 2008 2:21:10 AM
Subject: Copper gasket.
Hi! Yogesh,
Thanks for the input.
I understand the situation. And it is a straightforward case indeed!
Please refer ASME B16.5 Table 6 or Table 7 (I do not have it in front of me
right now.) with title as “Reducing … Flanges for Classes … “. Please read
the table and notes very carefully.
The case of modified flange (as indicated by you) is basically an
“Expanding Flange”. Code only permits reducing flanges with boring size
limits. Please read the table.
I hope that it will be clear to you.
For non-Code and poor engineering practice cases, finding a solution is
like “re-inventing wheels”.
I am sorry that I cannot help you in this case.
For additional reading, you can refer ASME B31.3 paragraph 304.4, 305 and
306, which talk about listed and unlisted components.
I think that you should also similarly respond to site, without breaking
your head.
Kind regards,
Bhatta.
Requested parameters:
1. #1500
2. design temp. 100°C
3. Fluid type - Glycol / De-Emulsifier (De-oiler) / Nitrogen Gas
Flange details
Piping side is having standard 16.5 raise face flange.
Instrument side is having Modified blind flange. 2" blind flange bored to
accomodate approx 2.5" instrument meter pipe. Due to this the raise face width at
instrument side is reduced and so standard 16.20 dimension gasket does not fit.
The flange type based on the drawing of vedor is similar to fig. 4a
ASME SECTION VIII DIV 1 appendix 2.
I have done the stress calculations as per ASME but that does not answer the point
raised by vendor i.e copper work-hardens and hence after
couple of cycles leak proof joint cannot be guranteed. As against spiral wound
gasket which has springing property and hence good for cyclic loadings.
Also the required torque calculated using the Min design seating stress required
for flat copper metal gasket (Table 2-5.1 of ASME) is very low as compared to the
standard torque values used for bolting. And if that values are used than the
initial stress on copper gasket goes beyond UTS. Since gasket will always in
compression comparing with UTS may not be correct. Is there any value fo copper
gaskets upto which the copper gaskets can be initially compressed?
Also would like to know if available, mechanical properties of sprial wound
gakset.
Regards
Yogesh
----- Original Message ----
From: "Bhattacharyya_ Bibekananda@ ke0.grp.kaneka. co.jp"
<Bhattacharyya_ Bibekananda@ ke0.grp.kaneka. co.jp>
Dear Yogesh,
Request you to indicate the following parameters please ...
1) Pressure Rating of the Flanges, in question;
2) Temperature of fluid, which will be wetting the flanges and gasket;
3) Name of fluid, which will be wetting the flanges and gasket;
4) Both flanges' facing details, like type, RF dimension, finish etc.
All these parameters are needed to do a quick check for the flanged joint's
integrity.
Guessing: What is the problem, if soft iron is used?
Kind Regards,
Bhatta.
At site on one of the flow meters flange facings of flowmeter flange and standard
piping flange do not match for the raise face dimension.
The raise face width at flowmeter end is less than standard flange. Hence
standard spiral wound gasket does not fit. Site came up with option of using
copper gasket. We enquired with gasket vendor and one of them said that copper is
not suitable for cyclic loading. He say's copper work-hardens and hence after
couple of cycles leak proof joint cannot be guranteed. As against spiral wound
gasket which has springing property and hence good for cyclic loadings.
Also for copper, can we use standard bolt torque for tightening?
Regards
Yogesh
----- Original Message ----
From: "kannan.sundaram@ linde-le. com" <kannan.sundaram@ linde-le. com>
Yes I am using Copper gasket in ethylene unit. But I am afraid without your
technical query presented, members will be unable to help.
With regards,
Kannan.
29/08/2008 16:30
materials and temperature limitation
Hi All,
Has anyone got any experience of using copper gaskets with standard B16.5 flanges
for ratings upto #1500 size 1/2" to 2" in process plants.
thanks
yogesh
----- Original Message ----
From: "kannan.sundaram@ linde-le. com" <kannan.sundaram@ linde-le. com>
This compilation done by Yayati-TICB. Source: Shell SPE.
Take note this is not an exahaustive list and various brands of PTFE does exist
having different limits. So take the advice of the valve manufacturer before
detailing your seat spec.
SEAT MATERIALS
Temperature range (deg.C)
Filled PTFE
-100
220
PEEK
-100
260
Modified PTFE
-200
200
EPDM
-20
110
VITON (fluoroelastomer)
-30
200
NEOPRENE
-20
85
NITRILE (NBR) (BUNA-N)
-10
100
STYRENE (SBR) (BUNA-S)
-40
70
NYLON POLYAMIDE
-40
90
ZYFLON
0
100
POLY OXY METHYLENE (POM)
-50
110
DEVLON -V (API GRADE)
-100
150
PER FLUOR ALKOXY (PFA)
-100
200
ETFE
-198
149
PCTFE
-250
150
VESPEL
-150
150
i want to know the temperature range of non-metallic seat material for ball
valves.
for which temperature range which non-metallic seat material is to be used in ball
valves?
Regards,
Swapnil Gorantiwar
.
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