Is it legal to grease packing before testing a valve? API 598 (section 4.4.1) infers that the packing should not be greased because it is a "sealing surface."

How can i obtain the the CV value of a control valve at 100% open, knowing the CV value at 80% open for example?

I just read an article about control valve leakage calculation details below.Cv max = 182, Flow rate at 100% open = 50 MMScfd The valve is ANSI class IV specification.

I am having trouble with the fire test of big dimension floating ball valves. And I will appriciate your comments if you have an idea about the possible reasons.

What seat material can be used for cryogenic ball valve in sour service? The temperature range is -198C-32C. Pressure ratings are 150#, 300# ,600# and 900# line.

I am looking for a solid hand wheel (no spokes) for a valve application. The challenge is that I need it to be 16" in dia.

When looking at a flow gain graph flow vs input voltage. If pressure can vary the gradient of the plot i.e higher pressure equals sharper increase in flow.

I was hoping i could get some help on placing a twin plated wafer check valve on the end of a pump rated at 300m3/h.