I was thinking a while ago about ways to make the whole water temperature experience better, and thought about using a complicated electronic system to measure the temperature of the water downstream and mix the hot and cold upstream to keep the temperature constant.

Then the other day I realized that a lot of the problems this would have with robustness, power use, etc. could be solved by making a completely passive, purely mechanical device that uses bimetallic elements to close and open valves.

Like those rotary thermostats that you turn, and a switch closes when the bimetallic strip pushes past wherever you turned it.

Instead, you could use bimetallic springs or something to close valves, so that the temperature always stays at the value you set it. So the faucet/shower control wouldn't be a "mix this much cold with this much hot" control; it would become a "aim for this temperature" control.
-- omegatron, Dec 17 2005

Thermostatic Faucet http://www.freepate...ne.com/5904291.html
Pretty much as described [csea, Jan 17 2010]

So, to understand, your invention idea centers upon the specific method of regulating water temperature at the tap rather than the idea of a faucet capable of maintaining a set temperature? The reason I ask is that such faucets exist but are usually electro-mechanical.
-- bristolz, Dec 17 2005


...So, you might not any water out, or just a trickle, but you wouldn't get freezing (or boiling) water in abundance? Hmm..a large sticky one.
-- Dub, Dec 18 2005


//The reason I ask is that such faucets exist but are usually electro-mechanical.

Correct. The idea is to be completely passive and mechanical instead of electro-anything.
-- omegatron, Mar 09 2006


An electro-mechanical faucet could derive power from the flow of water, though, and would thus be "passive" in a sense.
-- omegatron, Jan 17 2010


My shower works like this, as far as I know. There's a big coiled-coil of what looks like a bimetal strip inside it, over which the water flows. I can't swear to it, but I presume it's doing something like this.
-- MaxwellBuchanan, Jan 17 2010


..baked..
-- WcW, Jan 17 2010


y'all forgot constant pressure-ratio: also passive.
-- FlyingToaster, Jan 17 2010


nope completely baked. no novelty here at all
-- WcW, Jan 17 2010


A long time ago I patented a shower head using a bi-metal coil that turned a plate in front of the stream to divert it through a spout at the bottom of the unit if it was too hot or cold. Then you could adjust the water by hand and it would automatically direct the stream back at you when it was within a comfortable range.

Teledyne considered buying the idea but never did. I entered it in Nasa design contest and won some power tools though. Better than nothing I guess.
-- doctorremulac3, Jan 18 2010



random, halfbakery