Hi everyone. welcome to my blog. it been a long time i planned to make my own blog, there are so many reason to delay this plan. but…… yeah…. this is it. i manage to build my own blog. i hope i can learn something by building this blog. i know it’s like self talk, or talk in front of flat screen to express idea, thought, and some knowledge. i believe someday i’ ll start to talk in two ways eventually. thank you for coming to my blog buddy. really appreciate that. – yudhi-
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y-chen 
Hi Yudhi,
Good day to you. Impressed with your technical info which enable me to understand more.
Basically I need some advise from your end. I need to design a ball valve complying API 6D. The thing is i have no reference to start with in designing trim part and this ball valve need to be designed from scratch. Got search in the web if got any design guide or etc but don’t find a good one.
Simply said, to design trim part (ball, seat, stem, packing etc) seems difficult to me without reference. what design criteria / calculation to consider. I’m okay with B16.34, B16.5 & B16.10 but to my knowledge the trim design is up to manufacturer consideration as long as comply to std requirement.
Hope you can shed some light here.
Your kind assistance appreciated.
Regards,
Asmad
Hi Asmad,
Thank you for visiting my blog. I’m glad to hear if you find it useful.
Regarding ball valve design. To be honest, i cant share you any solid reference about how to design ball valve
in accordance with API 6D. Here’s what i can give you as a general comment.
Design wise, i believe its belong to proprietary information of each manufacturer about how they develop their valve mechanism,
special tolerance in manufacturing wise, especially for trim parts which mate each other,
and lesson learnt (study case) for each success and fail of prototype they made before they launch their products as their own signature,
exactly like you said.
I’m fully aware that design wise, ball valve is pretty common for process industry,
i can see there’s nothing significant difference even if we compare one product with another from different vendors side by side.
To the best of my knowledge, i haven’t found any websites that share every detail of how people design, calculate, manufacture, etc.
this is general steps and thing i can share you if you can reverse engineering from some product:
1. design – try to find one complete ball valve assembly drawing, study every step of the mechanism, how the parts mating each other,
draw some free body diagram (i studied my major in mechanical engr, hope you got what i mean), load analysis, stress involved,
safety factor.
2. determine the worst case scenario at what condition ball valve could consider fail, from the whole assembly fail, to each particular item failure.
for sure, it’ll be helpful if you can utilize 3D simulation software.
3. find some information from certain ball valve vendor (or engineering books), some valve vendor mention whats of their
material they’re using for their particular product. many reasons behind their decision for material selection
(cost, past experience, material availability, standard constraint, e.g. corrosion, galling issue).
4. If it possible, see the real example of one particular ball valve product
for cross checking your sense/understanding, measurement (if you can and consider it necessary).
5. definitely you need to combine design section that you have study with what you got from engineering standard like ASME, API, etc.
– API 6D can give you dimensional constraint of the whole assembly (but not each item parts since its totally up to designer),
quality constraint in order to compliant with it.
– you can look at (most) valve consist of common joint like flange, thread, etc. Check the normative standard on API 6D.
example: for flange connection, you can see ASME BPVC 1998 (as i look from API 6D, 22nd ed) to calculate and decide whether your design
is acceptable calculation-wise.
Hope it helps,
Regards,
Yudhi
Hi Yudhi,
Thanks for your constructive explanation. Yes it helps me to give an idea how to tackle to those unknown things. At least this are the things for me to consider in designing ball valve. Again thanks for your input.
Appreciate your kind support.
Regards,
asmad
Met this site in a morning and read a lot of useful things!
Thanks for visit
Hi Yudhi,
Is it possible to connect you on Linkedin?
Thank you