How to keep a water cooler filled from a rainwater tank

[Justin Richards]

Hi Folks,

I have finally installed a rain water tank.  I now fill my 19 litre
water cooler bottle from a small tap that I have piped into the house
at floor level.

Its a pain to fill as it is slow and the tap under the sink is awkward
to get to.

What I would like to do is sense the level in the cooler resevoir and
use a pump to top it up as it is used.

The tank and cooler hieghts require that I pump and shut off the flow
as the level in the water tank can be above or below the level of the
cooler.

I want to minimise on standby current, minimise on price and come up
with an elegant solution.  Naturally.

I have come up with 3 solutions.

1. Using a small easily available cheap windscreen washer pump, pump
the water up thru a loop of water pipe that extends above the top of
the water tank and then flows down thru pipe to the water cooler.  At
the apex of the water pipe loop at a point above the water tank
install something like a shephards crook so there is an opening to
air.

This will allow the water to be pumped up under pump pressure then
flow down to the cooler under gravity.  Once the pump is shut off the
water remaining on the tank side of the loop will return to the tank
and on the water cooler side will empty into the water cooler.  ie
there will be no syphon action as there will be an opening at the apex
of the loop.

I like this solution but is a little untidy plumbing wise and results
in more pipe exposed to the sun and I dont think it is good to have
rainwater at raised temperatures.

2. Use a sqeeze pump (do they use another name for these) like the
ones used to deliver accurate doses for medical purposes.  For me this
is difficult to build or aquire.  I like this as it provides a method
that combines pumping and shutting of the flow in one device.

3. Use a windscreen washer pump and a solenoid.  This is not a bad
idea but I cant seem to find small solenoid valves and havent
experimented (as I have none) to see if they significantly restrict
flow.  Most of these that I can source are desgned for irrigation and
as such the pressure they control would be quite high compared with
what a windscreen pump can deliver and not sure if they would work at
all.

Anyone have any clever solutions or know a good source of low pressure
smallish solenoid valves (in Perth Western Australia).

I think I have the control side of things sorted.  I considered reed
switch with floating magnet but I have decided to just use a probe
that detects the level of water by the drop in resistance.

Thanks for your time.  Any help greatly appreciated.

Cheers Justin
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[Josh Koffman]

On Tue, Jun 17, 2008 at 9:21 PM, Justin Richards
<justin.richards@...> wrote:
> 3. Use a windscreen washer pump and a solenoid.  This is not a bad
> idea but I cant seem to find small solenoid valves and havent
> experimented (as I have none) to see if they significantly restrict
> flow.  Most of these that I can source are desgned for irrigation and
> as such the pressure they control would be quite high compared with
> what a windscreen pump can deliver and not sure if they would work at
> all.


I'm not sure what's used on your side of the world, but over here
clothes washing machine repair shops are a great source of small
solenoid valves. Another option might be a lawn sprinkler supply.

Josh
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[Richard-177]

I'm just curious, Justin.  What to you do with the rain water that you
collect?


----- Original Message -----
From: "Justin Richards" <justin.richards@...>
To: "Microcontroller discussion list - Public." <piclist@...>
Sent: Tuesday, June 17, 2008 9:21 PM
Subject: [OT]: How to keep a water cooler filled from a rainwater tank

> Hi Folks,
>
> I have finally installed a rain water tank.  I now fill my 19 litre
> water cooler bottle from a small tap that I have piped into the house
> at floor level.
>
> Its a pain to fill as it is slow and the tap under the sink is awkward
> to get to.
>
> What I would like to do is sense the level in the cooler resevoir and
> use a pump to top it up as it is used.
>
> The tank and cooler hieghts require that I pump and shut off the flow
> as the level in the water tank can be above or below the level of the
> cooler.
>
> I want to minimise on standby current, minimise on price and come up
> with an elegant solution.  Naturally.
>
> I have come up with 3 solutions.
>
> 1. Using a small easily available cheap windscreen washer pump, pump
> the water up thru a loop of water pipe that extends above the top of
> the water tank and then flows down thru pipe to the water cooler.  At
> the apex of the water pipe loop at a point above the water tank
> install something like a shephards crook so there is an opening to
> air.
>
> This will allow the water to be pumped up under pump pressure then
> flow down to the cooler under gravity.  Once the pump is shut off the
> water remaining on the tank side of the loop will return to the tank
> and on the water cooler side will empty into the water cooler.  ie
> there will be no syphon action as there will be an opening at the apex
> of the loop.
>
> I like this solution but is a little untidy plumbing wise and results
> in more pipe exposed to the sun and I dont think it is good to have
> rainwater at raised temperatures.
>
> 2. Use a sqeeze pump (do they use another name for these) like the
> ones used to deliver accurate doses for medical purposes.  For me this
> is difficult to build or aquire.  I like this as it provides a method
> that combines pumping and shutting of the flow in one device.
>
> 3. Use a windscreen washer pump and a solenoid.  This is not a bad
> idea but I cant seem to find small solenoid valves and havent
> experimented (as I have none) to see if they significantly restrict
> flow.  Most of these that I can source are desgned for irrigation and
> as such the pressure they control would be quite high compared with
> what a windscreen pump can deliver and not sure if they would work at
> all.
>
> Anyone have any clever solutions or know a good source of low pressure
> smallish solenoid valves (in Perth Western Australia).
>
> I think I have the control side of things sorted.  I considered reed
> switch with floating magnet but I have decided to just use a probe
> that detects the level of water by the drop in resistance.
>
> Thanks for your time.  Any help greatly appreciated.
>
> Cheers Justin
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist 

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[Marcel Birthelmer]

What about an old fuel pump from a car? You'd want to clean it of course,
but in principle it could work.

On Tue, Jun 17, 2008 at 6:44 PM, Josh Koffman <joshybear@...> wrote:

> On Tue, Jun 17, 2008 at 9:21 PM, Justin Richards
> <justin.richards@...> wrote:
> > 3. Use a windscreen washer pump and a solenoid.  This is not a bad
> > idea but I cant seem to find small solenoid valves and havent
> > experimented (as I have none) to see if they significantly restrict
> > flow.  Most of these that I can source are desgned for irrigation and
> > as such the pressure they control would be quite high compared with
> > what a windscreen pump can deliver and not sure if they would work at
> > all.
>
>
> I'm not sure what's used on your side of the world, but over here
> clothes washing machine repair shops are a great source of small
> solenoid valves. Another option might be a lawn sprinkler supply.
>
> Josh
> --
> A common mistake that people make when trying to design something
> completely foolproof is to underestimate the ingenuity of complete
> fools.
>  -Douglas Adams
> --
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[Justin Richards]

hi Josh,

I considered the sprinker solenoids but figured they would restrict
flow from a very low pressure pump.

Most washing machines I have pulled apart seem to have 240v driven
solenoids.  i am sure modern machines would probably have low voltage
coils.

I suspect i will have to get hold of some of these and see just how
much they restrict flow.  I remember pulling one apart and thinking
they must use the water presure to assist in sealing the flow.  If the
pressure was low I suspect that the water could seep past.  Like I
siad I guess I will have to get hold of some and experiment.

Cheers

On Wed, Jun 18, 2008 at 9:44 AM, Josh Koffman <joshybear@...> wrote:

> On Tue, Jun 17, 2008 at 9:21 PM, Justin Richards
> <justin.richards@...> wrote:
>> 3. Use a windscreen washer pump and a solenoid.  This is not a bad
>> idea but I cant seem to find small solenoid valves and havent
>> experimented (as I have none) to see if they significantly restrict
>> flow.  Most of these that I can source are desgned for irrigation and
>> as such the pressure they control would be quite high compared with
>> what a windscreen pump can deliver and not sure if they would work at
>> all.
>
>
> I'm not sure what's used on your side of the world, but over here
> clothes washing machine repair shops are a great source of small
> solenoid valves. Another option might be a lawn sprinkler supply.
>
> Josh
> --
> A common mistake that people make when trying to design something
> completely foolproof is to underestimate the ingenuity of complete
> fools.
>  -Douglas Adams
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

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[Jinx-4]

> I have finally installed a rain water tank

Ah, the web has been all a-buzz with rumours about when it would
be done ;-)

> Anyone have any clever solutions or know a good source of low
> pressure smallish solenoid valves (in Perth Western Australia).

Hydroponic valves ? I've some here, about 30mm diameter, 24V,
that connect to 6mm tubing. Not sure of the possible max flow rate
but it sounds like it would be "reasonable" for your application

Or small fish tank/pond pumps. The ViaAqua ones I use for a pond
can shift a lot of water for as little as NZ$20

http://www.commodityaxis.com/ProductDisplay.aspx?id=7

8000 model -> 1000 gallons / hour (75 litres / min) to 10ft (3m)
480 model -> 100 gallons / hour (7.5 litres / min) to 2ft (600mm)

You can find them or like them at garden suppliers, pet shops,
hardware outlets etc

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[Justin Richards]

I like the sound of a fuel pump, that might just do the trick.

Cheers

Justin

On Wed, Jun 18, 2008 at 9:51 AM, Marcel Birthelmer
<marcel@...> wrote:

> What about an old fuel pump from a car? You'd want to clean it of course,
> but in principle it could work.
>
> On Tue, Jun 17, 2008 at 6:44 PM, Josh Koffman <joshybear@...> wrote:
>
>> On Tue, Jun 17, 2008 at 9:21 PM, Justin Richards
>> <justin.richards@...> wrote:
>> > 3. Use a windscreen washer pump and a solenoid.  This is not a bad
>> > idea but I cant seem to find small solenoid valves and havent
>> > experimented (as I have none) to see if they significantly restrict
>> > flow.  Most of these that I can source are desgned for irrigation and
>> > as such the pressure they control would be quite high compared with
>> > what a windscreen pump can deliver and not sure if they would work at
>> > all.
>>
>>
>> I'm not sure what's used on your side of the world, but over here
>> clothes washing machine repair shops are a great source of small
>> solenoid valves. Another option might be a lawn sprinkler supply.
>>
>> Josh
>> --
>> A common mistake that people make when trying to design something
>> completely foolproof is to underestimate the ingenuity of complete
>> fools.
>>  -Douglas Adams
>> --
>> http://www.piclist.com PIC/SX FAQ & list archive
>> View/change your membership options at
>> http://mailman.mit.edu/mailman/listinfo/piclist
>>
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[Richard Prosser]

2008/6/18 Justin Richards <justin.richards@...>:
> hi Josh,
>
> I considered the sprinker solenoids but figured they would restrict
> flow from a very low pressure pump.
>
> Most washing machines I have pulled apart seem to have 240v driven
> solenoids.  i am sure modern machines would probably have low voltage
> coils.
>

The 240V solenoids used in washing machines etc are rated for AC
operation. If you use them with a DC supply, they will probably
operate at a much lower voltage. Some new machines, do indeed, have
lower voltage (DC) coils.

RP
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[Spehro Pefhany]

At 09:21 PM 6/17/2008, you wrote:

>Hi Folks,
>
>I have finally installed a rain water tank.  I now fill my 19 litre
>water cooler bottle from a small tap that I have piped into the house
>at floor level.
>
>Its a pain to fill as it is slow and the tap under the sink is awkward
>to get to.
>
>What I would like to do is sense the level in the cooler resevoir and
>use a pump to top it up as it is used.
>
>The tank and cooler hieghts require that I pump and shut off the flow
>as the level in the water tank can be above or below the level of the
>cooler.
>
>I want to minimise on standby current, minimise on price and come up
>with an elegant solution.  Naturally.
>
>I have come up with 3 solutions.
>
>1. Using a small easily available cheap windscreen washer pump, pump
>the water up thru a loop of water pipe that extends above the top of
>the water tank and then flows down thru pipe to the water cooler.  At
>the apex of the water pipe loop at a point above the water tank
>install something like a shephards crook so there is an opening to
>air.
>
>This will allow the water to be pumped up under pump pressure then
>flow down to the cooler under gravity.  Once the pump is shut off the
>water remaining on the tank side of the loop will return to the tank
>and on the water cooler side will empty into the water cooler.  ie
>there will be no syphon action as there will be an opening at the apex
>of the loop.
>
>I like this solution but is a little untidy plumbing wise and results
>in more pipe exposed to the sun and I dont think it is good to have
>rainwater at raised temperatures.
>
>2. Use a sqeeze pump (do they use another name for these) like the
>ones used to deliver accurate doses for medical purposes.

"Peristaltic pump"

>  For me this
>is difficult to build or aquire.  I like this as it provides a method
>that combines pumping and shutting of the flow in one device.
>
>3. Use a windscreen washer pump and a solenoid.  This is not a bad
>idea but I cant seem to find small solenoid valves and havent
>experimented (as I have none) to see if they significantly restrict
>flow.  Most of these that I can source are desgned for irrigation and
>as such the pressure they control would be quite high compared with
>what a windscreen pump can deliver and not sure if they would work at
>all.
>
>Anyone have any clever solutions or know a good source of low pressure
>smallish solenoid valves (in Perth Western Australia).

I don't think appliance solenoid valves will work-- AFAIUI they're generally
pilot valves which depend on high pressure to operate.

>I think I have the control side of things sorted.  I considered reed
>switch with floating magnet but I have decided to just use a probe
>that detects the level of water by the drop in resistance.
>
>Thanks for your time.  Any help greatly appreciated.
>
>Cheers Justin
>--
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>View/change your membership options at
>http://mailman.mit.edu/mailman/listinfo/piclist

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@...             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com



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[Justin Richards]

> Ah, the web has been all a-buzz with rumours about when it would
> be done ;-)

As I expected, I excitedly told enough people and very happy when it
arrived, ah the simple things.  Strangely enough it rained soon after
and hasn't stopped. Where was Murphy.

> Hydroponic valves ? I've some here, about 30mm diameter, 24V,
> that connect to 6mm tubing. Not sure of the possible max flow rate
> but it sounds like it would be "reasonable" for your application
>
> Or small fish tank/pond pumps. The ViaAqua ones I use for a pond
> can shift a lot of water for as little as NZ$20
>
> http://www.commodityaxis.com/ProductDisplay.aspx?id=7
>
> 8000 model -> 1000 gallons / hour (75 litres / min) to 10ft (3m)
> 480 model -> 100 gallons / hour (7.5 litres / min) to 2ft (600mm)
>
>

I considered pond pumps but that would require controlling 240v
device, which I could do but slightly complicates the setup, and most
of the ones I saw made it difficult to connect to the inlet, ie they
needed to be submerged.  The $20.00 ones only had a head height of
about 1 meter not sure if that would do the trick.

Cheers justin
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[Jinx-4]

> I considered pond pumps but that would require controlling 240v
> device, which I could do but slightly complicates the setup

You can get DC versions but they are quite a bit more expensive. I
don't have the specs to hand but know that they don't use a lot of
power so even a small relay would do for control

> and most of the ones I saw made it difficult to connect to the inlet,
> ie they needed to be submerged

Yes, they do need to be submerged when running, but not necessarily
in the water you want to move. The pump can be mounted in a separate
smaller tank, connnected via a U-bend (so the pump tank doesn't drain)
to the main tank

> The $20.00 ones only had a head height of about 1 meter not sure
> if that would do the trick

ISTR I paid NZ$29.95 for a 2300 model and that's got quite some
pumping power to over 2m with a 25mm pipe

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[Gordon Williams]

Hmm, sounds like a great place for bacteria to grow...

You may want to consider food grade plastics or other materials that are
safe to be in contact with potable water.

My advice would be to leave the rain water for watering your vegetable
garden.

Regards,

Gordon Williams

----- Original Message -----
From: "Justin Richards" <justin.richards@...>
To: "Microcontroller discussion list - Public." <piclist@...>
Sent: Tuesday, June 17, 2008 9:21 PM
Subject: [OT]: How to keep a water cooler filled from a rainwater tank

> Hi Folks,
>
> I have finally installed a rain water tank.  I now fill my 19 litre
> water cooler bottle from a small tap that I have piped into the house
> at floor level.
>
> Its a pain to fill as it is slow and the tap under the sink is awkward
> to get to.
>
> What I would like to do is sense the level in the cooler resevoir and
> use a pump to top it up as it is used.
>
> The tank and cooler hieghts require that I pump and shut off the flow
> as the level in the water tank can be above or below the level of the
> cooler.
>
> I want to minimise on standby current, minimise on price and come up
> with an elegant solution.  Naturally.
>
> I have come up with 3 solutions.
>
> 1. Using a small easily available cheap windscreen washer pump, pump
> the water up thru a loop of water pipe that extends above the top of
> the water tank and then flows down thru pipe to the water cooler.  At
> the apex of the water pipe loop at a point above the water tank
> install something like a shephards crook so there is an opening to
> air.
>
> This will allow the water to be pumped up under pump pressure then
> flow down to the cooler under gravity.  Once the pump is shut off the
> water remaining on the tank side of the loop will return to the tank
> and on the water cooler side will empty into the water cooler.  ie
> there will be no syphon action as there will be an opening at the apex
> of the loop.
>
> I like this solution but is a little untidy plumbing wise and results
> in more pipe exposed to the sun and I dont think it is good to have
> rainwater at raised temperatures.
>
> 2. Use a sqeeze pump (do they use another name for these) like the
> ones used to deliver accurate doses for medical purposes.  For me this
> is difficult to build or aquire.  I like this as it provides a method
> that combines pumping and shutting of the flow in one device.
>
> 3. Use a windscreen washer pump and a solenoid.  This is not a bad
> idea but I cant seem to find small solenoid valves and havent
> experimented (as I have none) to see if they significantly restrict
> flow.  Most of these that I can source are desgned for irrigation and
> as such the pressure they control would be quite high compared with
> what a windscreen pump can deliver and not sure if they would work at
> all.
>
> Anyone have any clever solutions or know a good source of low pressure
> smallish solenoid valves (in Perth Western Australia).
>
> I think I have the control side of things sorted.  I considered reed
> switch with floating magnet but I have decided to just use a probe
> that detects the level of water by the drop in resistance.
>
> Thanks for your time.  Any help greatly appreciated.
>
> Cheers Justin
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

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[M. Adam Davis-2]

I like the idea of a pump and a solenoid, but I'd consider arranging
it differently and use a flow through pump (ie, the pump would allow
siphoning when not active).

Connect the one tank to the other with the pump in the middle as
usual.  At the apex of the tube (Which has to be slightly higher than
the maximum level of either tank) put a T in with the solenoid
allowing air to enter the tube.

Diagram:
http://flickr.com/photos/adavis/2590441784/

Note that the solenoid with the air tube can reside inside one of the
tanks as long as the apex of the main tube is above the maximum of
both water levels.  This will make it so you don't need to move the
apex of the tube into the light.  Unsightly tubing could be hidden
with just one open end of a tube exposed somewhere.

Further, with a more complex control and monitoring scheme, you could
possibly use the pump to merely prime the siphon, and then when tank 2
is full enough open the solenoid to stop the flow.  Very low power
with a low power solenoid.  the solenoid can be very small relative to
the water flow and still stop the siphon action, and it could even be
a relatively cheap air solenoid.

If the inner tank is at a higher level then you'd merely use the pump
continuously.   This requires more information about the levels of the
tanks relative to each other, though, so it may not be practical
unless you can arrange them so one is always higher than the other.

The pump can be anywhere along the main line.  Regardless of your
solution you might consider putting a cheap float valve on the inside
tank in case the electronic level monitor fails, controls fail, or
other parts fail.  This would prevent flooding.

If you want to go very cheap, you can take the solenoids you migh find
that run on 120VAC and re-wind the coil for a lower voltage.  They
aren't terribly energy efficient, though, so you might still be using
a lot of power to overcome the friction and spring in the valve.

Also, note that the the typical sprinkler valve has a small solenoid
you might be able to use without too much modification:
http://www.spudtech.com/content.asp?id=21

-Adam

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[Justin Richards]

Thats perfect.

I mentioned that an opening at the apex is a possible solution  but
downside was ugly exposed pipe that is prone to heating, but I never
thought to put it *inside* the tank.  Brilliant.

No need for air solenoid if the opening of the Tee is high enough as
gravity will help here, or better yet a one way valve.  Let the Air in
but not the water out.

This also means that i can easily use a submersible pond pump.

Great work.  I knew the list would come thru.

*Inside* the tank, huh just couldnt see the last piece of the puzzle.

Thanks to all.

Cheers Justin

> I like the idea of a pump and a solenoid, but I'd consider arranging
> it differently and use a flow through pump (ie, the pump would allow
> siphoning when not active).
>
> Connect the one tank to the other with the pump in the middle as
> usual.  At the apex of the tube (Which has to be slightly higher than
> the maximum level of either tank) put a T in with the solenoid
> allowing air to enter the tube.
>
> Diagram:
> http://flickr.com/photos/adavis/2590441784/
>
> Note that the solenoid with the air tube can reside inside one of the
> tanks as long as the apex of the main tube is above the maximum of
> both water levels.  This will make it so you don't need to move the
> apex of the tube into the light.  Unsightly tubing could be hidden
> with just one open end of a tube exposed somewhere.
>
> Further, with a more complex control and monitoring scheme, you could
> possibly use the pump to merely prime the siphon, and then when tank 2
> is full enough open the solenoid to stop the flow.  Very low power
> with a low power solenoid.  the solenoid can be very small relative to
> the water flow and still stop the siphon action, and it could even be
> a relatively cheap air solenoid.
>
> If the inner tank is at a higher level then you'd merely use the pump
> continuously.   This requires more information about the levels of the
> tanks relative to each other, though, so it may not be practical
> unless you can arrange them so one is always higher than the other.
>
> The pump can be anywhere along the main line.  Regardless of your
> solution you might consider putting a cheap float valve on the inside
> tank in case the electronic level monitor fails, controls fail, or
> other parts fail.  This would prevent flooding.
>
> If you want to go very cheap, you can take the solenoids you migh find
> that run on 120VAC and re-wind the coil for a lower voltage.  They
> aren't terribly energy efficient, though, so you might still be using
> a lot of power to overcome the friction and spring in the valve.
>
> Also, note that the the typical sprinkler valve has a small solenoid
> you might be able to use without too much modification:
> http://www.spudtech.com/content.asp?id=21
>
> -Adam
>
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> Tuesday April 22
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