Tank Fill Setup

[cadiehl]

I have a 100,000 gallon water tank with a 6" fill line. We are modifying the system to provide automated tank fill capability. We need to do this without electronics if at all possible. The new fill valve will need to open after 1000 gallons of water has been pumped out of the tank, and close once the tank reaches design fill level. (the tank, by code, is supposed to hold a two hour supply of water, it only holds half of that, which is why we need to start filling soon after the pumps kick on) What is the best way to accomplish this? Fill valve type? Pneumatic controller setup? Any help would be greatly appreciated.

Thanks,
CD

 

[Zapster]

http://www.cla-val.com/

 

[rcooper]

Would a ballcock work?

 

[cadiehl]

Cla-Val is where we are looking at the moment for a valve. My problem is figuring out the pneumatic portion of the system. How to control the Cla-Val without electronics. The part of the puzzle that is missing is what goes between the tank and the Cla-Val to provide automatic fill capability. Basically when the tank level decreases by 2" I want the Cla-Val to open, and when it is filled, the Cla-Val to shut. Tank level is about 22'.

 

[rcooper]

http://www.johnsonvalves.co.uk/Data/Data Sheet No. 11.02 - 501 Float Valve.pdf

How about something like the valve on the link above? The valve will start opening as soon as the pumps start, and will open progressively as the level falls. It will not require any further hardware, but will require regular maintenance.

 

[cadiehl]

We do not want a float valve. That is what we are replacing. The existing float valve inside the tank is corroded beyond recognition. We are now going to do this from outside the tank in the fill line.

 

[Zapster]

cadiehl,

Take a look at:

http://www.controlvalves.com/series/8000/8000.html

Have you talked to a manufacturer’s sales rep about your needs? There should be no problem to install a pilot operated valve using the upstream pressure for control. Both OCV and CAL-Val should have what you need. I have more experience with OCV. Keep in mind that when using upstream pressure to control a diaphragm operated valve with a small pilot valve you will have a slightly greater pressure drop across the valve. Be careful when calculating your pressure drop across the valve. For a given flow rate you must determine how far the valve will be open. This is not as simple as it seems at first glance.

Regards


Just saw your last response and now I am confused. How do you plan to monitor the tank level without electric controls or a pilot operated float??

 

[Zapster]

Oops, I did not mean a pilot operated float, I was thinking float operated pilot valve and just wrote it backwards. Keep the main flow valve out of the tank; and install the float operated pilot valve where you can access it, from the top of the tank. Then maintenance becomes easier, most of your control lines are external to the tank, and your flow valve is not limited in size. I recommend hanging the float operated pilot valve from a manway so it is easy to work on or inspect.

Regards

 

[Zapster]

Here is a picture of what I was thinking:

http://www.controlvalves.com/series/8000/8000_features.html

 

[cadiehl]

I'll refer back to my original post. Pneumatically. We need some kind of pneumatic controller (using head pressure)between the valve and the tank, that will monitor the drop in pressure when the tank begins to empty then actuate the Cla-Val. Once it has emptied about 2" or so, the valve will open. The float is not an option. We have looked at exactly what you referred to and it is not an option. Our tank configuration does not provide that capability. I am looking for someone who knows what to put between the valve and the tank to get this to work, pneumatically. I believe this can be done, however, probably not that common I guess.

 

[cadiehl]

Zapster, I think we got it. The OCV 3330 Altitude Control Valve may be perfect for what we need. It is all done hydraulically. No electric, no pneumatics, from what I can tell. Time to make some calls I guess. Thanks!!

 

[SteveWag]

Any of the water-works valve people, OCV, Cla-Val, Golden Anderson, Ross, etc will offer an altitude valve that will be either full open or full closed with a differential of 6" in water level w/o pneumatics or electronics, in fact, no power is required at all. 2" will be difficult. For very small differentials, make sure the level sensing line is tapped to the tank, not to the fill draw pipe. The reversal of flow as the tank goes from filling to emptying will exceed 2” H2O. The other thing is the need for enough pressure to fill the tank, if the available pressure drops below the tank full pressure, the altitude valve will open full.

Steve