Dear Dhwani,
Sorry for the late comment as I was on vacation.
Just to add to the trailing mail, the bellow seals usually in gate and globe valves in toxic services for better sealing and emission control, are to be comply with MSS-SP-117, which covers the design as well as the testing requirements. More important of the cyclic life requrirements. Only after these testing a bellow can be certified for the purpose.
The bellow sealed valves, apart from the usual inspection code requirements, it has to comply with the cyclic test, helium leak test, hydrotest at 1.5 times the design press. in open position.
So pl. refer MSS-SP-117 for more details and the std ref. should have been part of the valve datasheet as the testing cost is different.
With regards,
Kannan Sundaram.
| "kannan_cit" <kannan.sundaram@linde-le.com> Sent by: notify@yahoogroups.com 14/02/2008 08:53 |
|
--- In piping_valves@yahoogroups.com, "Shyam Herur" <herur.shyam@...>
wrote:
**
*hydraulic shell pressure test:* the valve, prior to assembly with the
bellows, in partially open position, shall be subjected to pressure
test
with water(with suitable corrosion inhibitor) at 1.1 times the
maximum rated
working pressure of particular pressure rating class of the valve.
the test
pressure and acceptance criterion shall be as per BS6755-part I or
API598 or
ANSI B 16.34.
*hydraulic seat pressure test*:the valve, in closed position, shall be
subject to pressure test with water (with suitable corrosion
inhibitor) at
1.1 times the maximum rated working pressure of the particular
pressure
rating class of the valve. the test pressure and acceptance criterion
shall
be as per rate A of BS6755 part I or API 598 or ANSI B 16.34.
*pneumatic pressure test*:the valve, upon final assembly including the
bellows, in partially open position shall be subjected to pressure
test by
dry air or GN2 at 1.1 times the maximum rated working pressure of the
particular pressure rating class of the valve. the test procedure and
acceptance criterion shall be as per rate A of BS6755 part I or API
598 or
ANSI B 16.34.
information courtsey: *National aerospace laboratories Bangalore*
Regards
shyam
On 1/31/08, Sanjay_Gandhi@... <Sanjay_Gandhi@...> wrote:
>
>
> Shwani,
>
> Hydrotest of bellow seal valve is carried out with bellows
installed. The
> manufacturer do the low pressure air testing internally to ensure
the welds
> in bellows are free from any leakage. Then the hydrotest of
complete body
> including bellows will be undertaken. The valve is kept open and
the bellows
> will be subject to external pressure.
>
> When conducting the seat closure test the bellow will not see the
> pressure.
>
>
> Best Regards,
>
> Sanjay Gandhi
>
>
>
> *desaid@...*
> Sent by: materials-welding@googlegroups.com
>
> 31/01/2008 12:29 PM Please respond to
> materials-welding@googlegroups.com
>
> To
> piping_valves@yahoogroups.com cc
> materials-welding@googlegroups.com Subject
> [MW:542] Hydrotesting of Bellow Seal Valves
>
>
>
>
>
> Dears,
>
> Can any one inform how testing (hydro & pneumatic) of Bellow seal
valves
> are generally carried out? Shell Test & seat test both.
> i.e. with bellows or without bellows?
>
> If there is some detailed procedure available of reputed vendor
then pls.
> send.
>
> Thanks & Regards,
> Dhwani Desai.
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