Hi Erik
Local air atmospheric pressure inside air bell is P atm = 1 barg + 1
bara = 2 bara
.
Pressure inside pipe is P abs = 0 bara.
Gauge pressure is defined as Pabs - Patm = 0 - 2 = -2barg. QED. However you will probably have to use a DP gauge to measure.
I think most engineers can design a pipe (or a bell) which will stand a vacuum by designing to stay below the critical buckling pressure.
Either run the pipe through the sides of the air bell (sealed at the intersections) or run the pipe up into and down out of the air bell, or have the pipe sealed at both ends.
We engineers can do anything!
Cheers
Steve
-----Original Message-----
From: Erik Scheir [mailto:erik.scheir@pandora.be]
Sent: Tuesday, January 18, 2005 8:12 AM
To: PipingDesign@yahoogroups.com
Subject: RE: [PipingDesign] about surge
If the pressure above the waterlevel is atmospheric, then the pressure 10.3 m below the waterlevel is 1 barg (gauge) and an air bel with a 100% vacuum will collapse.
How can you run a pipe through an air bell?
Cheers,
Erik
Van: Steve McKenzie [mailto:mechproj@xtra.co.nz]
Verzonden: zondag 16 januari 2005 19:46
Aan: PipingDesign@yahoogroups.com
Onderwerp: RE: [PipingDesign] about surge
I am normally not one to split hairs, but couldn't resist this one: Consider an air bell 10.3m below water level, with a (perfect) vacuum pipe passing through it. Inside the air bell is a pressure gauge connected to the pipe. What is the gauge pressure?
Cheers
Steve
-----Original Message-----
From: Erik Scheir [mailto:erik.scheir@pandora.be]
Sent: Sunday, January 16, 2005 11:45 PM
To: PipingDesign@yahoogroups.com
Subject: RE: [PipingDesign] about surge
I used this sofware perhaps even before you were born, but what has that to do with te fact that -2 bar does nor exist on the earth. Try to use Flowmaster its even better then impulse from AFT and you will never see results with pressure nodes below 0 bar.
Erik
Van: gautam wayse [mailto:captain_wayse@yahoo.co.in]
Verzonden: zaterdag 15 januari 2005 9:30
Aan: PipingDesign@yahoogroups.com
Onderwerp: RE: [PipingDesign] about surge
hi
friend
better to go for impulse software for surge analysis
.from applied flow technology,.
use --- Erik Scheir <erik.scheir@pandora.be> wrote:
erik
-----Oorspronkelijk bericht-----
Van: Omid Hamlehdar [mailto:omid_7_ae@yahoo.com]
Verzonden: dinsdag 11 januari 2005 7:19
Aan: PipingDesign@yahoogroups.com
CC: mechproj@xtra.co.nz; erik.scheir@pandora.be
Onderwerp: [PipingDesign] about surge
Hi all
I have a project for water handling, a pipeline with
100 km length, I am
studying about surge in it according to a probable
rapture in pipe and I am
going to close two valves surrounding rapture point to
avoid wasting water
and to find out about surge cause by closing valves.
Any body has experience in this regards? How shall we protect our system?
I have heard from Erhard valve, they recommend a valve
called "pipe burst
control valve" to avoid wasting water when there is a
rapture, this valve
will be closed in around 2 min and this will cause
surge in system, in some
point we have -2 bar minimum pressure. I know that you
may need to know
about the profile but generally I would like to know
how shall we suppress
this surge?
Best regards
Omid
[Non-text portions of this message have been removed]
http://www.pipingoffice.us/ =========================================Main site: http://www.pipingdesign.com
Yahoo! Groups Links
http://www.pipingoffice.us/ =========================================Main site: http://www.pipingdesign.com
To visit your group on the web, go to: http://groups.yahoo.com/group/PipingDesign/
To unsubscribe from this group, send an email to: PipingDesign-unsubscribe@yahoogroups.com
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
http://www.pipingoffice.us/ =========================================Main site: http://www.pipingdesign.com
Yahoo! Groups Links
[Non-text portions of this message have been removed]
http://www.pipingoffice.us/ =========================================Main site: http://www.pipingdesign.com
Yahoo! Groups Links
http://www.pipingoffice.us/ =========================================Main site: http://www.pipingdesign.com
Yahoo! Groups Links
[Non-text portions of this message have been removed]
http://www.pipingoffice.us/ =========================================Main site: http://www.pipingdesign.com
Yahoo! Groups Links Received on Tue Jan 18 21:32:00 2005
This archive was generated by hypermail 2.1.8 : Mon Oct 27 2008 - 20:24:06 EDT