Geoff
I thought the installers may have encased with concrete to improve
durability. If so, access to the headworks (for leaf removal) will have been
left without concrete cover. If everything is encased then you are probably
right about cracking or the flanges have an alignment problem. The original
drawings, if still in existence, may shed some light.
If the valves are cracked then I would probably attempt a repair method
similar to what you are proposing, but without epoxy filler (except as a
last resort). As an alternative you may want to consider is grinding back to
good metal, bands on either side if the valve. Ultrasonic (?) thickness
measurements prior to grinding would be advisable. Hopefully the pipe is
still OK. You are going to need luck on your side I think. A contingency
plan would be a good idea.
I have not done a job like this; always steel, so hopefully another group
member has attempted a similar task, and can respond.
Cheers
Steve McKenzie
-----Original Message-----
From: Geoff Stone DD&D Australia [mailto:blenrayaust@yahoo.co.uk]
Sent: Monday, August 26, 2002 9:27 AM
To: <a href="/group/PipingDesign/post?postID=h-hT2uudNzAC74MLqhYuxXhkhZR09j3e2j5cwVfl_jsmprKf7YrqxU1go8sP_njK_27Cdts1h8y9d-nmDOId-uq4DTeZ">PipingDesign@yahoogroups.com</a>
Subject: RE: [PipingDesign] Connections for a DN 1200 Cast Iron Main
STeve,
The concern is that the existing valves have cracked bodies for we cannot
understand why they have been encased in concrete. One proposal is to chip
away
the concrete and examine however if the casting is cracvked we are left with
the same dilemma. These valves are ona system that provides upwards of 60 %
of
Sydney's water.
Geoff
--- Steve McKenzie <Mechproj@xtra.co.nz> wrote:
> Hi Geoff
>
> While not gate valves, I was involved with refurbishing hydro station
> multiple headgates about the same size at a small hydro power station of
> similar age. They were in essence a gate valve however. In that case, for
> some of the valves, we found it cheaper and less risky to remove and
> refurbish the leaf and to dress the ways in situ. I cannot recall whether
> the body seat was replaced or dressed.
>
> Cheers
>
> Steve McKenzie
>
>
> -----Original Message-----
> From: Geoff Stone DD&D Australia [mailto:blenrayaust@yahoo.co.uk]
> Sent: Friday, August 23, 2002 4:53 PM
> To: paul bowers
> Subject: [PipingDesign] Connections for a DN 1200 Cast Iron Main
>
>
> We have a DN 1200 (48") water supply line in cast iron with a cement
lining.
> The pipe was laid in 1912. We need to remove a gate valve and install a
new
> unit. The existing valve is encased in concrete.
>
> The planned method is to cut the pipe away from the valve, remove pipe and
> valve in one piece and install new flange spools and valve. Our problem is
> we
> need to fit to the existing cast iron a flange such that the flanged
spool
> can
> be attached.
>
> Firstly we shall excavate the pipe and check out the surface to see if we
> can
> use a coupling with lip seals but expect the surface to be pitted. We are
> considering repairing this with an epoxy if not too bad.
>
> We seek your experiences in this type of problem.
>
> =====
> Design Detail and Development (a division of Blenray Pty Ltd)
> We specialise in pipe network and waterhammer analysis, pipe stress
> analysis, buried pipelines and the design of thermoplastic pipe systems.
> Local tel 0402 35 2313 fax 02 8850 2313
> Overseas tel 61 402 35 2313 fax 61 2 8850 2313
> Mail Address PO Box 1351 Castle Hill NSW 1765 Australia
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> 877-610-8924.
> www.texasflange.com
> =====================================================
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Texas Flange - a good source for information on industrial flanges, all they
ask is for referrals for designs they help with.
877-610-8924.
www.texasflange.com
Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a>
--- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.380 / Virus Database: 213 - Release Date: 7/24/2002 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.380 / Virus Database: 213 - Release Date: 7/24/2002Received on Sun Aug 25 18:37:00 2002
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