Advisory has been cirtculated related to the blow-out of the stem on ball
valves. Look for the following features:
Blowout proof stem to prevent stem removal while valve is installed.
Stem grounded to the body to prevent lectrical discharge.
Gear operatir for 10" and larger (those torque are really quite signifcatnt)
Design that prevent overtunring of the ball.
Do not use ball valve in open-ended service u nless it pass the seat leakgae firetest. Firetest to API 607 and purchase o spec to API 608 (prior to 608, we normally specify ball valve to MSS-SP-72 and B16.34).
-----Original Message-----
From: <a href="/group/PipingDesign/post?postID=bA5hcD82a9xX0V6kt3_AT-g7QKGkcU3oznfFM8IFQSXPw3vwTSFY8x8JN7aJaAPSbvVr76XmntZL7YoeXl5NtLWTLh9Kew">geoff.stone@lendlease.com.au</a> [mailto:<a href="/group/PipingDesign/post?postID=bA5hcD82a9xX0V6kt3_AT-g7QKGkcU3oznfFM8IFQSXPw3vwTSFY8x8JN7aJaAPSbvVr76XmntZL7YoeXl5NtLWTLh9Kew">geoff.stone@lendlease.com.au</a>]
Sent: 23 August, 2001 9:23 AM
To: <a href="/group/PipingDesign/post?postID=Y3DGU0Axr3dCBjvSzQlHmcg5DWzRHQ1-g2N4gFsBqe-OwQUOXLmaLDEZtRlwxTwianhUwvwBrnONofSmPLNDlmxHCRQ">PipingDesign@yahoogroups.com</a>
Subject: Re: [PipingDesign] Ball Valve
Reduced port ball valves are used on an economic basis only. There are no advantages in this type of valve other than price.
Full bore is used where you wish to pig the line or headloss is critical.
Remember that there are other differences. There are trunnion mounted ball
valves that are again more expensive. The benefits of this type of valve are
that they are more robust as they have separate bearings and do not rely
upon
the seat to support the ball. Operating torque is lower and thus actuaor
size
can be smaller.
The other difference is that ball valves can be general purpose or firesafe.
The
latter are used in the petro chem industry and are required to comply with
BS
5351 and tested to BS 5146 ( the USA equivalent I think is API 6D). They
have a
metal seat as a reserve to the primary teflon seat. The teflon seat must be
unreinforced so that in the vent of a fire the ball can seat on the metal
reserve seat. If glass reinforced seat are used in the event of a fire there
ii
s no surety that the ball will seal on the metal seat.
Another type of ball valve is the Orbit quater turn valve. This valve has a
configuration where the ball moves away from the seat before it turns. This
valve is used to stop wear on the seat when the fluid may contain sand and
grit
such as in the oil patch or on off shore rigs.
For control applications there is the vee ported ball valve. This provides better control than a conventional ball valve. Used in the pulp and paper industry especially.
.
<a href="/group/PipingDesign/post?postID=VWBuS3dOi3slA0Zy_t2izxhFArLL-mXxSLRDAkQ9AeLa_cy5KvPWVeFi39jgjORyZN0zm1oJFppMc6vsHw">Rudiawan@Kvaerner.com</a> on 23/08/2001 04:00:18 PM
Please respond to <a href="/group/PipingDesign/post?postID=Y3DGU0Axr3dCBjvSzQlHmcg5DWzRHQ1-g2N4gFsBqe-OwQUOXLmaLDEZtRlwxTwianhUwvwBrnONofSmPLNDlmxHCRQ">PipingDesign@yahoogroups.com</a>
To: <a href="/group/PipingDesign/post?postID=Y3DGU0Axr3dCBjvSzQlHmcg5DWzRHQ1-g2N4gFsBqe-OwQUOXLmaLDEZtRlwxTwianhUwvwBrnONofSmPLNDlmxHCRQ">PipingDesign@yahoogroups.com</a>
cc:
Subject: [PipingDesign] Ball Valve
There two kinds of ball valve : Reduce bore and Full bore. Which is the specific condtions to use of each type ?
Thanks
rudiawan
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Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a> Received on Sat Aug 25 04:34:00 2001
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