Piping and Valve Engineering: September 2009

Thursday, September 24, 2009

Fwd: Re: Double offset butterfly valve with metal seat

Pl. read catalogs for more understanding.

The subject of seating in double ot triple offset butterfly is litte bigger than other valves due to the emphasis given to the application and operating conditions.

There are quit a few proprietary seat designs. For eg. the graphite layers gets eroded in few weeks to months due to operating condition resulting in big leak and pressure drops. The profile of the seat and disc is also important which developes the cavitation effect and pitting of the seat. So in the selection of a seat the operating condition such as the opening angle, pressure, which in turn will affect the operating pressure in turn the system design itself. So a well thought process is essential in the butterfly valve type and seat selection.

In solid seat the cost makes the big difference.

Regards,
Kannan

--- In piping_valves@yahoogroups.com, "ashoksiva1982" <ashoksiva1982@> wrote:
>
> Dear all,
>
> I have an enquiry for Double offset butterfly with metal seat. The design pressure shall be 40 bar. Can any one know the seating arrangement of competitor valves.
>
> I got some information from the below link. I need some more arrangement for the above requirements.
>
> http://www.sz-yll.cn/upload/814/200631485558638680174.pdf

Wednesday, September 23, 2009

UL LISTED/FM APPROVED Valves fro fire water network(Sea Water) Options

There are quit a no. of vendors with FM/UL in the market.

However I would suggest Mapag GmbH, having UL certification for a wider size range and for all kind of standard designs.

Even Tyco has only upto 12" with UL.

Regards

Kannan

Respected Sirs,

In our project, we have fire water network(sea water used as fire water).
As per requirements, all valves shall be UL LISTED/FM APPROVED.
we have valves sizes ranges from 2" to 30"- we require almost more than 2500 valves.

May i have list of vendors from USA,UK or EUROPE who can supply these valves.
Your esteeem reply ill be highly appreciated.

from
Ashok

Welding qualification of very low sulfur steels.

----- Forwarded Message ----
From: kannan_cit <kannan_cit@yahoo.com>
To: piping_valves@yahoogroups.com
Sent: Wednesday, September 23, 2009 7:26:46 PM
Subject: [piping_valves] Welding qualification of very low sulfur steels.

Quit some time ago, I was having great difficulty in finding mills manufacturing steels with sulfur limited to 0.001% max. due to a wrong prescription by one of the well known PMC. Though it was resolved with higher relaxation later, I started to look into the issues concerning the restrictions posed in the sulfur content in steels, which were mainly added to increase the machinabilty, in various applications including the H2S/Sour service applications. The article in the link provides an insight in welding a low sulfur material.

The issue in the context of welding is that, while sulfur content is reduced the surface tension is reduced resulting in wider concave welds with lesser penetration, which pose a problem in thick walled pipes which are common in sour services. The insert ring solution proposed in the link below may solve the problem of higher weld penetration, which calls for different weld procedure. Similar to ASME BPE standard's prescription of limitation on, weld sulfur with appropriate quality check, does such requirement called in the BPV.

I seek our member's suggestion on the subject of welding procedure qualification, in such applications where sulfur content is restricted from 0.002% to 0.010% in sour/H2S applications.

http://www.thefabri cator.com/ tubepipefabricat ion/tubepipefabr ication_article. cfm?ID=533

With regards,
Kannan

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