Number of Turns to Open/Close a Gate Valve
Number of Turns to Open/Close a Gate Valve
(OP)
Recently, I was reading thread164-168796: 6 inch gate valve position (http://www.eng-tips.com/viewthread.cfm?qid=168796). In that thread, "bimr", with reference to AWWA, said that number of turns equals NPS times 3 plus 2 or 3. But I saw in AWWA M44-96, Fig. 3-1, that for 6" valve number of turns is 26. Actually, with numbers in the table, number of turns is NPS times 3 + 10. Am i right?





RE: Number of Turns to Open/Close a Gate Valve
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Number of Turns to Open/Close a Gate Valve
Every 6 inch I've ever closed has been 18-22 turns.
RE: Number of Turns to Open/Close a Gate Valve
What would you be doing, if you knew that you could not fail?
RE: Number of Turns to Open/Close a Gate Valve
RE: Number of Turns to Open/Close a Gate Valve
exceptions
some older valves (50+ years) have a shallower thread pitch, 4x or 5x
also some older valves operate as a left hand
gate valves mounted sideways will also have a gearbox, this is to overcome the crud that must be pushed out of the way instead of just crushed, I know of 24" 1960 era valves with 158 turns, and when they have not been operated for 20 years take three men an hour to exercise
Hydrae
RE: Number of Turns to Open/Close a Gate Valve