3 Inlets, one underground tank , Level & Pump control

[waseem19]

All,

I have an underground tank "top of the tank is at ground level" that will be fed by three separate lines: 2 lines coming from wells (several pumps in several wells) and another pressurized gravity fed line.

I'm looking into providing a control to shut off supply when the tank reaches its overflow level; I want to use the following:

1- 1 float valve at the inlet from the pressurized gravity fed line.
2- No valves at the other two inlets supplied from the well pumps.
3- The float valve or another sensing system "pressure switch or level sensor will send a signal to all the well pumps to shut off once water level reaches overflow"

Well this work? Another suggestion was to use altitude valves for the two lines from the wells but will this work here?

I was concerned that for order for these altitude valve to work it should be able to sense the water level in the tank and it cannot since the tank is below them, a solution for this off course to simply dip the line down along with the altitude valve just before the tank. Am I visualizing this right?

If I still have to put these altitude valve won't their operation because the pump to burn eventually since the pump will see its shut off head too often?? That is if I don't provide another control method for the pumps

Thank you all.

 

[unclesyd]

Lots of questions.

What is the fluid?

What is the size tank are you concerned with?

What are the flow rates into and out of the tank?

How is the material taken from the tank?

 

[waseem19]

unclesyd,

-fluid is TSE , its an irrigation tank,
-the tank is 8000 cum in volume.
-flow is approximatly 300 l/s.
-there will pumps at the surface of the tank, it will draw water from below ,( the tank is 3m deep) and pump it into an irrigation distribution network.

thanks for any help.

 

[unclesyd]

I have had much time to work on the problem so here are a few points and questions.

What you are calling an altitude switch I assume is a pressure switch. Pressure switches will work with dip tubes. The use a displacement type switch as the switch of last resort.

Could you pump directly from your wells to irrigation network. This could be a continuous or an intermittent bypass condition based on the tank levels.

Some more specifics would help get some better answers. A better description of the input piping. What is meant by several pumps on tanks.
Some better description of type pumps, capacities, and flows.
Is this a new installation or and existing system.

 

[waseem19]

unclesyd,

Thanks again, to clarify

1- I'm not really concerned about the system after the tank; I'm looking to control the system feeding the tank only.
2-I have not said "altitude switch" maybe this is the same thing as "altitude valve" which I did mention, but I really don't know whether they are the same thing.
3- maybe I confused things when I said ( dip the line down....) I only meant to make the altitude valves deeper than the high water level in the tank so the valve can feel it.
4- there isn't anything complicated about the inlet piping , simply three separate lines entering an underground tank from top.
5- there will be 10 wells, each will have 2 or more pumps.
6- the irrigation tank and its pumps are proposed, everything else is existing but diversion will be done to take these inlets to the new irrigation tank.
7-we cannot pump directly from the wells to the distribution network.

I only want to see if the concept I proposed in my original post will work and wanted to make sure I understand how the altitude valve works.

I could get the type/flow of every existing pump but it will take weeks, I’m only at concept design stage here so all I need is to propose a control concept.

thank you again for your time unclesyd.

 

[JimCasey]

While there are undoubtedly many ways to do this, the very simple way is to use a level switch installed on top of the tank. When the level rises to the switch point, the Level switch changes state. Use the switch to drive a relay driving the valve, and also output to the motor starters on the pumps to deenergize the pumps on high level.

There are many vendors. Magnetrol is one of the best known. You can set up the Magnetrol switch so that it has a wide deadband, and will switch the pumps off when the tank is full, and it can wait until the tank is near empty before it switches the pumps on. That way the pumps are not in start-stop mode and they will last longer.

If you install the floats/Displacers of the magnetrol in a large pipe, it will act as a stilling well and sloshing or swirling in the tank will not affect the floats/displacers.