Pressurizing water distribution system w/o tanks
Pressurizing water distribution system w/o tanks
(OP)
All,
Here is the situation: We have a rural water system which consists of a well, one lead pump, one lag pump, one 250K gallon aboveground storage tank, a pneumatic control valve, and underground piping.
I need to take the tank out of service for maintenance. In the interim (about 3 weeks), I need to keep the sytem up to pressure (a minimum of 20 psi).
I would like to bring in temporary storage, such as a bladder tank. The operations manager would like to change the pump controls to have the pumps run continuously and discharge excess water to drain via a pressure relief valve.
Has anyone had any experience with 'tankless' water systems? Any items I need to be aware of? We've never done anything like this, so any basic direction would be great. I don't like the op manager's idea because it would waste water. On the other hand, bladder tanks pose a security risk and take up a lot of space.
Thanks in advance!
Here is the situation: We have a rural water system which consists of a well, one lead pump, one lag pump, one 250K gallon aboveground storage tank, a pneumatic control valve, and underground piping.
I need to take the tank out of service for maintenance. In the interim (about 3 weeks), I need to keep the sytem up to pressure (a minimum of 20 psi).
I would like to bring in temporary storage, such as a bladder tank. The operations manager would like to change the pump controls to have the pumps run continuously and discharge excess water to drain via a pressure relief valve.
Has anyone had any experience with 'tankless' water systems? Any items I need to be aware of? We've never done anything like this, so any basic direction would be great. I don't like the op manager's idea because it would waste water. On the other hand, bladder tanks pose a security risk and take up a lot of space.
Thanks in advance!





RE: Pressurizing water distribution system w/o tanks
I also don't see a necessity to run the pumps continuously. Set the controls so that a pump turns on when the pressure lowers below 20 psi. Your pressure relief is there for pressure relief, not for continuous flow. Depending on the type of pressure relief valve you have, it may introduce pulsations or even surges into your system by using it in a continuous manner.
The proposed operation is wasteful of both water, power and could even overheat the pumps if the flow through the relief valve is less than the pump's minimum flowrate.
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Pressurizing water distribution system w/o tanks
RE: Pressurizing water distribution system w/o tanks
Since you are shutting down anyway, maybe it's something to consider.
3 weeks sounds like a long time.
Charlie
www.facsco.com
RE: Pressurizing water distribution system w/o tanks
In your case the big issue would be where you go with the recirc, any chance of being able to put it into the tubing/casing anulus on the water well to keep from losing it?
David
RE: Pressurizing water distribution system w/o tanks
Wellguy, VFD recommendation seems premature and why run the pumps all the time? Are you really recommending blowing excess flow through a pressure relief?
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Pressurizing water distribution system w/o tanks
Biginch, I do not recommend blowing the excess off through pressure reliefs, however I have seen it done on many occasions on a short term basis.
I am not sure if a vfd is the right answer with out more info. It depends on the system size and usage. I was just suggesting options. I have installed vfds on several small systems so that they can avoid the expense of large storage tanks. It may be a good fit or not.
RE: Pressurizing water distribution system w/o tanks
RE: Pressurizing water distribution system w/o tanks
I've seen some residential-water wells where the pump and production tubing are lowered into a casing and in that case I don't know why you wouldn't be able to recycle back to the casing. It sounds like municipal wells have a different configuration. If so please disregard my inappropriate suggestion.
David
RE: Pressurizing water distribution system w/o tanks
Many municipal wells are larger versions of residential wells. There is a well casing extending through the water table. Right below the frost line is a Pitless Adapter. It might be a sealed spool or drop fitting of other design. In anycase, it is possible to dump water over the spool or past the drop fitting, but then you are dumping water on top of these units, and they have wires and ports that you would constantly be pouring water over, and they were not designed for that.
Of course, we don't know if the OP is in a building or using pitless wells.
For the people that wanted to recurculate water back into the well, I designed some drop fittings that are installed under the spool, and then piped down to the water level instead of a free fall. You can't just add a pipe to these wells, the spool and motor/pump still have to be pulled out.
Charlie
www.facsco.com