Electric valves?

Hi,

I posted this earlier on comp.robotics.misc, but thought I might get 
more insight here. Sorry if you read both groups...

I'm looking to build something for myself and would like some input.  I 
want a device I can hook up to my household plumbing to allow me to 
control temperature and pressure of my shower instead of just Hot and 
Cold. Ideally it would have temperature sensors and motor-controlled 
valves.  The temperatures sensors would try to hold temperature somewhat 
constant. Of course a few safetys would be needed as well, ie if the 
device fails it should not allow water to pass etc.

Any suggestions or pointers for the mechanical part of this design?

Thanks,

--buddy

On Sat, 26 Mar 2005 02:42:12 +0000 (UTC), Buddy Smith
<nullset.spamtrap@dookie.net> wrote:

>Hi,
>
>I posted this earlier on comp.robotics.misc, but thought I might get 
>more insight here. Sorry if you read both groups...
>
>I'm looking to build something for myself and would like some input.  I 
>want a device I can hook up to my household plumbing to allow me to 
>control temperature and pressure of my shower instead of just Hot and 
>Cold. Ideally it would have temperature sensors and motor-controlled 
>valves.  The temperatures sensors would try to hold temperature somewhat 
>constant. Of course a few safetys would be needed as well, ie if the 
>device fails it should not allow water to pass etc.
>
>Any suggestions or pointers for the mechanical part of this design?
>

Electricaly controlled water valves are use quite bit with sprinkler
systems. The normal ones are normally only fully-open, or fully
closed. I am sure there would be valves available for sprinkler
systems which can be controlled between fully open, and fully closed.
Whether these valves can hnadle the temperature of the hot side I am
not sure. For the temperature sensor, you can quite easily use a
thermo-couple of one of the silicon temperature sensors. 

Regards
   Anton Erasmus

"Buddy Smith" <nullset.spamtrap@dookie.net> wrote in message 
news:d22i62$gti$1@news-int2.gatech.edu...
> Hi,
>
> I posted this earlier on comp.robotics.misc, but thought I might get
> more insight here. Sorry if you read both groups...
>
> I'm looking to build something for myself and would like some input.  I
> want a device I can hook up to my household plumbing to allow me to
> control temperature and pressure of my shower instead of just Hot and
> Cold. Ideally it would have temperature sensors and motor-controlled
> valves.  The temperatures sensors would try to hold temperature somewhat
> constant. Of course a few safetys would be needed as well, ie if the
> device fails it should not allow water to pass etc.
>
> Any suggestions or pointers for the mechanical part of this design?
>
> Thanks,
>
> --buddy
>

You'll want a motorised mixing valve like this one...
http://hbctechlit.honeywell.com/request.cfm?form=95C-10887

On the safety side you need something to shut off the flow if the power 
fails. The cheapest valve for this can be found on washing machine inlets. 
They are simple solenoids and snap shut when the power is removed.

If you want to spend some more money these valves are also designed for hot 
water and have a fail safe. If the power fails then you can hear a clockwork 
mechanism winding the valve back to the unpowered position, open or closed, 
your choice. http://content.honeywell.com/uk/homes/motorise.htm

Peter

Peter <moocowmoo@newprovidence.demon.co.uk> wrote:

> You'll want a motorised mixing valve like this one...
> http://hbctechlit.honeywell.com/request.cfm?form=95C-10887

Ahh, I think motorised mixing valve was the search term I couldn't come 
up with :)

Much thanks!

--buddy

In article <d22i62$gti$1@news-int2.gatech.edu>, 
nullset.spamtrap@dookie.net says...
> Hi,
> 
> I posted this earlier on comp.robotics.misc, but thought I might get 
> more insight here. Sorry if you read both groups...
> 
> I'm looking to build something for myself and would like some input.  I 
> want a device I can hook up to my household plumbing to allow me to 
> control temperature and pressure of my shower instead of just Hot and 
> Cold. Ideally it would have temperature sensors and motor-controlled 
> valves.  The temperatures sensors would try to hold temperature somewhat 
> constant. Of course a few safetys would be needed as well, ie if the 
> device fails it should not allow water to pass etc.
> 
> Any suggestions or pointers for the mechanical part of this design?
> 
Do you realize that this has already been done without any do-it-
yourself wiring?   Look up  "thermostatically controlled faucet"
I would guess that they use a bimetallic element to control
the proportions of hot and cold water to the shower head.
Once you've got the temperature right through the faucet,
you can control the pressure with a valve on the shower
head.

I can sympathize with your problem though.  Our house
has a well system where the pressure varies from
40 to 70 psi,  and the washing machine is closer
to the hot water tank than the shower.  If someone starts up
the washer while you're in the shower, look out!
It's particularly annoying at low pressure when the
washer is in the part of the cycle where it 
sprays the spinning clothes for about 5 seconds
out of every 10.


Mark Borgerson

Mark Borgerson <mborgerson@comcast.net> wrote:

> Do you realize that this has already been done without any do-it-
> yourself wiring?   Look up  "thermostatically controlled faucet"
> I would guess that they use a bimetallic element to control
> the proportions of hot and cold water to the shower head.
> Once you've got the temperature right through the faucet,
> you can control the pressure with a valve on the shower
> head.


In this case I could use a motor controlled valve for flow 
adjustment plus a thermostatic mixing valve for temperature. Is there an 
electronically adjustable thermostatic valve?

ttyl,

--buddy