6 inch gate valve position
6 inch gate valve position
(OP)
Recently I took a exam asking how many turns does it take to close a 6 inch gate valve for the full open position? I dont know the answer, so I guessed 19 turns of the whell operator since I had no references to go by. Does any one know the answer? Does anyone care? Just curious. BTW the question was civil service exam.





RE: 6 inch gate valve position
How many turns does it take to open/close a gate valve?
The AWWA operating formula for opening/closing a gate valve is 3 times the nominal valve size plus 2 or 3 turns of the operating nut.
Example; 6 x 3 = 18 plus 2 or 3 = 20 to 21.
RE: 6 inch gate valve position
RE: 6 inch gate valve position
It should be remembered this will not hold true on large valves that have a gearbox installed (either spur gears or bevel gears.) The gearbox should have a nameplate attached giving the gear ratio. This needs to be factored in.
For example, for a 60" valve, the number of shaft turns should be 3 X 60 + 2 = 182 turns. If the gearbox has a 3 to 1 ratio, then the turns figure must be multipled by 3. So, with a 3:1 gearbox, a 60" valve will take 546 turns of the input shaft to fully open/close the gate.
Quite commonly, the valve manufacturer will have this final figure stamped on the nameplate also.
RE: 6 inch gate valve position
good luck