Type of Valve
Type of Valve
(OP)
Hi,
I am not too familiar with Valves. I have to select one to add at the end of a 12" PVC pipe that drains a man made lake when we want to lower the water level during the rainy season. So for the most part, there will be very little pressure in the line. Someone recommended a plug valve, but after reading some posts i'm inclined to recommend a ball valve. I need it to be water tight also. so no leaking.
Thanks in adavance.
I am not too familiar with Valves. I have to select one to add at the end of a 12" PVC pipe that drains a man made lake when we want to lower the water level during the rainy season. So for the most part, there will be very little pressure in the line. Someone recommended a plug valve, but after reading some posts i'm inclined to recommend a ball valve. I need it to be water tight also. so no leaking.
Thanks in adavance.





RE: Type of Valve
RE: Type of Valve
I don't understand the water tight requirement exactly. If absolutely no leakage of water is allowed into your spillway, then maybe you are stuck with a gate, globe, plug, or ball and perhaps two of them.
Otherwise, butterfly is where I would start looking. If this is something you'll use once a year at a relatively known time, throw an extra blind flange at the outlet to control any small leaks during the dry season.
- Steve Perry
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RE: Type of Valve
How is your security? Can a mischievous person drain the lake when no one is looking? Over a long weekend? You may want a lockable valve or put the valve and blind flange in a secure area.
Good luck,
Latexman
RE: Type of Valve
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Type of Valve
Good luck,
Latexman
RE: Type of Valve
5 acres would be difficult through a 12" for sure. I could go with pond.
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Type of Valve
RE: Type of Valve
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Type of Valve
If you have some need for throttling capability then the butterfly valve would be good, but I'd back it up with a gate valve.
But, take my advise with a grain of salt. I work with nuclear components and we really don't like water going where it's not supposed to!
Patricia Lougheed
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RE: Type of Valve
RE: Type of Valve
But, big-inch ball valves are quite expensive.
I would use a knife gate valve (really thin) for this kind of application where the design pressure is a few dozen feet of head and the transient velocities can be really high. These valves have a resilliant seat (like most ball valves) where typical gate valves have a hard seat that foul easily in "drain the swamp" kinds of applications.
Butterfly valves work for this, but I've had problems with the plates breaking off in high-velocity liquid flows. The vibrations from von Karmaan Streets are just too hard on a bluff body in the flow.
I wouldn't use a plug valve for this application on a bet--if you don't lubricate a plug valve then it doesn't move and service like you're talking about is typically short on preventive maintenance programs.
David
RE: Type of Valve
For a dam with an outlet going through the embankment, normally the valve is on the upstream side, in the lake. this allows the outlet pipe to remain unpressurized except during operation of the valve. sediment and trash is an issue, the valve needs to pass trash without clogging. typical would be a slide gate. If this is a deep lake than differential pressure can have some impact on your selection and it will increase the torque required to open the valve.
RE: Type of Valve
RE: Type of Valve
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso