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What kind of reduction in coefficient of friction can be achieved with the use of ENP against stainless?

Scotsinst, Thanks for your input, this is what I've always speculated and realized after pouring over formulas and methods in Crane 410 and ISA. It’s ironic you mention the Q-ball because the valve was sold by assuming a Cv curve similar to that obtained by a Neles Q-ball of the same NPS...

Jim, These pressures are specified as gauge, and the fluid is water. I have realized the difficulty of this design. My superior has patented the trim in the past for noise control but it has never been produced to provide specific and "made to order" Cv's. Now that the design has been "sold"...

Jim, It seems that I have interpreted the data incorectly. My valve must be capable of inducing a maximum pressure drop of 600 psi (750 in vs. 150 out), and a minimum delta p of 200 psi. So my challenge is to determine at what positions I can maintain a 150 psi pressure at the outlet, all...

I am designing a quarter turn ball control valve. I have system inputs for pressure ranging from 350-750 psi and a flowrate of 52 gpm. It has also been given that due to another valve downstream, the backpressure at my valve's outlet will be 150 psi. With these values it seems I automatically...

PaoloPemi, you are understanding the design well, given the amount of detail I've provided and I appreciate your input. Allow me to elaborate: The inlet of the valve is 1" in diameter. The seat trim pieces have a pattern of various diameter holes, so when the valve is cycled and the ball is...

Desertfox, CoryPad, UncleSyd, thanks very much for your input I really appreciate it.

Desertfox, My concern is the reduced surface area under the nut. The surface pressure exists due to preloading force distributed evenly across the total nut/bonnet contact surface area. So at any point under the nut, even where there is less bonnet material touching the nut due to the...

Desertfox, correct I am accounting for the area lost due to the machining area. I know there are many discussions and threads concerning preload, and I am still working to grasp the concept entirely. From what I infer, you want to preload your fasteners to provide enough force to overcome the...

Sorry took me a sec to figure it out...http://files.engineering.com/getfile.aspx?folder=09bd3fbf-de36-4f71-96fa-e4bed0c76d95&file=bearing_area_sketch.pdf

A bolt circle was machined .200" too small on a valve bonnet (top flange). Production saw fit to just remachine the bolt circle at the correct dimension ontop of the smaller bolt circle, and as a result there is now 14% less nut bearing surface area (see attached sketch). How should I approach...

The input: I have a 2" nominal pipe (2.375" outer diameter) that I need to socket weld into a bore I'm referencing from B16.11. B16.11 for a 2" nominal pipe gives "B", the socket bore diameter, as 2.426/2.406. My questions: 1) Why is there such a large gap (.031" min) between pipe OD and...

I am designing a 1", quarter-turn ball control valve and in need of some overall guidance. The inlet and outlet seat trims are modified with a pattern of holes intended to help reduce flow. The valve is required to pass water at a flow rate of 19 gpm, with inlet pressures ranging from 750 psig...

I see. Any idea though of a specification for buttwelding end dimensions less than 2-1/2, which is the miniumum given by B16.25.

hah!! Seriously let me know so I can be sure not to go there.

B16.25 Table 1,I-1; Dimensions of Welding Ends gives values for NPS down to 2-1/2". Where could I obtain dimensions for buttwelding ends less than 2-1/2"?

Thanks for the info TVP, I think I've got it. For example, MIL-T-9046J's classification of CP-2 requires a minimum yield strength of 55 ksi, which would correspond to ASTM's Grade 3 min. yield. I appreciate it.

I've seen differing abbreviations for Grade 2 Titanium on manufacturer and supplier websites. Some call out Grade 2 as CP-2, while others, CP-3. Some define Grade 3 as CP-2. Which is it? ASTM B 348-08a does not define nor distinguish any abbreviations for Titanium.

Because BX gaskets are pressure energized seals, does this qualify them as "self-energized" as defined by Section VIII Div. 2? Table 4.16.1 (gasket factors for determining bolt loads) gives "m" and "y" as 0 for self-energizing gaskets, but the seating stress for ring joints is very high. Which...

So look elsewhere. The job opportunities in Houston are ridiculously prevalent for most in oil & gas. Screw getting underpaid. Ask for a raise.