Recent content by John3p

bcd, Wow! What an excellent explanation. You've not only clarified a long standing question I've had, in doing so you've also enabled me to be better at my job. Although 80% of the ball valves I spec' and purchase must be piggable and minimize energy loss, the cost savings of installing...

With trunnion mounted ball valves, you'd need some info from the manufacturer. But with floating ball valves it's simply a function of the pressure differential on either side of the ball. Apply the delta-P to the effective cross-sectional area of the ball's upstream side to figure the force...

TBP, Thanks for providing some applications where reduced port ball valves are commonly used. I can understand how the reduced port style might be less expensive in smaller sizes, especially if the manufacturers are using the same casting for both types of balls and simply machining a larger...

Having been in the industry over 8 years, I'm almost embarrassed to ask, but it's something that been bugging me: Considering that pressure/energy loss is almost always undesirable, and the fact that they're not easily pigged, why and under what circumstances would a reduced port ball valve ever...

Coefficients of friction are determined empirically. You must specify the other material with which the Incoloy is in contact. Also, surface profiles (smoothness) and conditions (wet, dry, lubricated, etc.) must be considered. Additionally, static (starting from rest) and dynamic (maintaining...

Although it's costly, if you're working with a large drawing you might try adding some more memory to your printer. A well defined problem is half solved.

I got so wrapped up in the fundamentals that I failed to address your question: >My question is, many slots pr. ft could I make to keep the >same compression and tensile strength in this casing joint? Answer: It is impossible to remove portions of the pipe and keep the same tensile strength...

With steel, yield strength in compression and tension will be virtually equal. The strength of the pipe itself is a function of the material's yield strength and the pipe's cross sectional area (assuming straight, constant diameter pipe). If you reduce the area in any way (i.e. decreasing wall...

One of the most troublesome aspects of the projects I manage is incomplete specifications. If the clients would spend the same time and energy specifying complete design conditions and scopes of supply as they do preparing contracts designed to indemnify themselves against any and all...

TPB, Thanks. I'll look into acquiring that little IPT book. A well defined problem is half solved.

Interesting question. I'm not sure what we can infer from this, but the Machinery's Handbook lists identical head markings for: SAE - Grade 5 & ASTM A449 SAE - Grade 8 & ASTM A354 Grade BD I'd be interested in a more definitive answer. A well defined problem is half solved.

Tom, I believe Appendix 1 of II-D provides the explanation for the two different stress values. A well defined problem is half solved.

Falco, I do not find a listing for 18% Cr 9% Ni in the tables. However, there is a listing for 18% Cr 8% Ni Type 304 Steel Plate: Max. Allowable Stress @ 500°F = 12.9 ksi A well defined problem is half solved.