How to refill water filter automatically?

[laurie71]

I'm trying to figure out a way to automatically refill my Berkey water filter. I plan to extend the line feeding the water dispenser / ice maker on the fridge to supply the water filter. I'm OK with modifying the Berkey for this, I just need to figure out what kind of water valve system will work...

The filter has two stacked tanks; the top one is the pre-filter fill tank, the bottom one is the holding tank for filtered water. What I want to achieve is that when the holding tank is empty, the fill tank gets topped off. I can't just keep the top tank filled at all times; the water would keep draining through the filters and overflow the holding tank.

What I'm thinking is a pair of float valves; one in the holding tank that will open when the tank is empty, and one in the fill tank that will close when the tank is full. If I run the supply line through both valves that should do it, provided I can flow enough water to fill the top tank before enough water filters though into the holding tank to shut off the empty-sensor valve...

Does anyone have any better solutions, or any recommendations for suitable water valves what would work well for this applications?

Thanks!

Laurie

 

[nealtw]

Welcome to the site, some of the people in know should be along soon.

 

[frodo]

ice maker fill switch .if your handy. get one and modify to fit your tank. the "arm" on the ice maker can be fitted with a float
to start stop flow. just my opinion

 

[laurie71]

I guess the ice maker fill switch would have suitable flow characteristics Thanks, I'll look into that.

 

[nealtw]

Perhaps if each tank had it's own switch but both floats were in the lower tank the one for the upper tank set lower to stop the flow to the upper tank sooner.

 

[frodo]

not for nothing, the dump is where i would look, their's gold in that pile of junk!!!!!!

we have a local dump, i bug the hell out of that guy, old bed frames [angle iron]
dryers [motors] grabbed an old metal fridge, turned it into a smoker

 

[laurie71]

Perhaps if each tank had it's own switch but both floats were in the lower tank the one for the upper tank set lower to stop the flow to the upper tank sooner.

Nice idea, but it takes a while for the water to pass through the filters so I woould need to manage fill levels directly.

 

[laurie71]

not for nothing, the dump is where i would look, their's gold in that pile of junk!!!!!!

we have a local dump, i bug the hell out of that guy, old bed frames [angle iron]
dryers [motors] grabbed an old metal fridge, turned it into a smoker

I don't even know where the dump is here, I'll have to find out...

 

[nealtw]

Nice idea, but it takes a while for the water to pass through the filters so I woould need to manage fill levels directly.

I'm stuck on the idea so I will try to back it up

The upper tank only has to refill when the lower tank needs to be refilled and it only need enough water to be filtered and not to much.

Without knowing any numbers, i will just make some up, you would have to do some reseach to come up with the real numbers.

Let's say when the lower tank is half full when you want it to refill, that would be where you want the float to turn on the water.
You should know how much water to put in the system, let's say 1 gallon.
Now how long does it take to put 1 gallon of water in the top tank, let's say 1 minute.
How much water is filtered in 1 minute in inches, let's say 1 inch, that is where you want the float to turn off the water top the top tank.

I still see two problems 1. float travel may not be enough between on and off and this could be improved by slowing the water entering the top tank. just a valve set to drible would do that.
2. A clean filter would move water faster and would slow after time( I think)
so you would want to leave some safety in the system. Like with my numbers if it can take 1 gallon set it so it takes 3/4 gallon so when it slows down it still won't overflow.

 

[nealtw]

I found this, different system but you might find the valves interesting,

[ame]https://www.youtube.com/watch?v=rhB567Gwywc[/ame]

 

[laurie71]

I'm stuck on the idea so I will try to back it up

...

2. A clean filter would move water faster and would slow after time( I think)
so you would want to leave some safety in the system. Like with my numbers if it can take 1 gallon set it so it takes 3/4 gallon so when it slows down it still won't overflow.

There's the problem; the difference in flow rate between a new set of filters and a set that needs replacement is quite a bit... It might be possible to get something that works at both ends of that range, but I doubt it'd be optimal.

 

[nealtw]

There's the problem; the difference in flow rate between a new set of filters and a set that needs replacement is quite a bit... It might be possible to get something that works at both ends of that range, but I doubt it'd be optimal.

Perhaps if you started with a new filter and the water at a fair rate with a valve, as the system slowed you could adjust the flow up
down a little. Over time you might learn how much to decrease the flow per week or month or what have you.

 

[laurie71]

That video gives me an idea; there's a hydroponic supply store nearby, I bet I can find suitable float valves and tubing there. The auto shutoff in the video is probably not what I want, but that mini float valve might be perfect.

Thanks!

 

[bud16415]

I didn't know much about how your system works so I watched a few on line videos about that. It seems the filters are in the upper tank and work best when the lower tank is empty and the the upper tank is fully filled and allowed to drain down thru the filters. If that's the case add a third holding tank like a toilet bowl that sits and waits full. When the last drop is removed from the lower filtered tank flush the top tank and start over. The one they showed filtered fairly fast when full and took about an hour to filter all the water.


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[laurie71]

I didn't know much about how your system works so I watched a few on line videos about that. It seems the filters are in the upper tank and work best when the lower tank is empty and the the upper tank is fully filled and allowed to drain down thru the filters. If that's the case add a third holding tank like a toilet bowl that sits and waits full. When the last drop is removed from the lower filtered tank flush the top tank and start over. The one they showed filtered fairly fast when full and took about an hour to filter all the water.


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I'm not sure of the benefit of the additional holding tank? I'm not sure the flow rate through a standard refrigerator supply line but I would expect that the upper tank should be able to be filled fast enough straight from that.

About an hour sounds about right with a new set of filters (depending on how many are installed). However, they do tend to filter more slowly as they age and start to clog.

 

[bud16415]

I guess my point was you don't want to have a set up where you don't take advantage of the full length of the filters. It's similar to how a mound septic system works with a dosing tank. You don't want to trickle water in you want the full impact and pressure of a full tank. To your point of the differential fill setup if you can fill the tank in a few minutes and it takes an hour to drain maybe that's close enough.


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[laurie71]

I guess my point was you don't want to have a set up where you don't take advantage of the full length of the filters. It's similar to how a mound septic system works with a dosing tank. You don't want to trickle water in you want the full impact and pressure of a full tank. To your point of the differential fill setup if you can fill the tank in a few minutes and it takes an hour to drain maybe that's close enough.


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Yeah that was my thinking; I guess I should run some flow rate tests to see how long a fill would take.

 

[nealtw]

If you set your fill for an old filter you should have no trouble wth a new one.

 

[slownsteady]

I'd like a little background info on how the filter works now. I can guess that it's a gravity feed from the upper to lower tanks. Do you fill the upper tank by hand? What keeps the lower tank from overflowing normally? If it is sealed between the two tanks, the lower tank should not need a valve because no water can enter if it is full.

 

[bud16415]

The two halves are not sealed and the normal filters are two cylindrical filters where the water enters thru the sides and runs out a spout that pokes thru the side. So when the tank is full the whole surface is filtering and you get max flow rate and filter life I would think. You can also add filters in the lower tank for fluoride and other substances that are in line to the flow. I don't think the OP has those.

If the bottom tank is half full and you fill the top tank I would say you would get a spill. If the top tank was sealed like a bottle dispenser the the flow would stop when the water sealed air from coming in. I don't think the top lid is air tight. That's why I suggested a third dosing tank with a fill float working similar to a toilet tank. Or just run a pipe to it with a valve. I can see the awkward part of one of these is bringing a bucket from the sink to the unit everyday.

If I had one I would run a line from the lower tank to my coffee maker. Wait I think if you pour coffee in this you get pure water out.




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