A product that keeps the bathtub from overflowing and reheats cold water. It would be attached to the outside of the tub or the nozzle, so when the water gets to a certain user set point the facet turns off. And a built in enhancement would filter and re-heat the water if it gets cold, or could be used to keep it warm the whole time. The product would also filter any germs, soap, etc... and reuse the water, for the time used, also heats filtered water to a set temp.
-- krigre55, Nov 29 2007

infinity tub http://www.us.kohle...roducts/why_sok.jsp
you probably want something like this. [pyggy potamus, Nov 30 2007]

Secret overflow drain http://z.about.com/...1/0/D/W/bathtub.jpg
See the switch under the faucet? There's usually a hidden drain behind it. [5th Earth, Nov 30 2007]

Option 1: Pressure transducer.

Option 2: Conductivity sensor at preset height.

Option 3: Ritzy ultrasonic doodads.
-- Texticle, Nov 29 2007


Aaaand leaving the hot water trickling in at the same rate as it drains through the safety drain at the top doesn't work for you... why?
-- globaltourniquet, Nov 29 2007


[krigre55], welcome to the Halfbakery.
-- baconbrain, Nov 29 2007


[bigsleep], I'm not sure I understand your question, or indeed whether it is a question. I stand by my options, based on the assumption that the desired depth is something less than than the exact maximum the bath is capable of. I read the overflowing problem as one of forgetting to turn the tap/faucet off during unattended filling, not one of sloshing water over the gunwales due to occupant activity.
-- Texticle, Nov 29 2007


I dont think so bigsleep. I agree that making a water sensor could be a trick undertaking if you want it to measure minute differences.

I agree with [Texticle]. The way the idea reads is to prevent overflow occurring when the tub is *initially* filled. after that it's up to you. given, there is a mechanism for recirculating the water, but that doesn't necessarily mean it ties into the drainage system.

I believe a pressure system would work, with a scale in the bottom of the tub tied to a valve. Hell, the whole tub could be on a mechanical valve so as the tub fills, the tub lowers and closes the valve. After that weight is reached, any additional weight will not cause the drainage of water, but it does prevent the release of more water. which brings the need for a water heater/ re- circulator. Which, again, is separate from the plumbing of the tub.
-- bleh, Nov 30 2007


Yeah, that part is nasty. Filter fungus, eww.

But the fill sensor problem is trivial, really--any engineer could design three different devices just from the title of this idea. I'm the guy who's usually demanding methods, but I'm giving [krigre55] a pass on that aspect.

A depth sensor could be electronic or mechanical, and could be set to either fill to the proper level with or without an occupant. A dispensing sensor could be either a timer to shut off the faucet, or a volume counter. The user might need to learn just how much water can be put into an empty tub without causing overflow upon entering.

This is probably already done in Japanese bathtubs. Let me look. . . . Found nothing specific, but systems to cobble something up out of.
-- baconbrain, Nov 30 2007


//Option 3: Ritzy ultrasonic doodads.// [marked-for-tagline]
-- pertinax, Nov 30 2007


I'm a little confused over the necessity for the first half of this idea. Bathtubs nearly all have overflow drains, just holes located high in the tub that lead straight to the main drain. They won't shut the water off for you, but they'll stop you from flooding your bathroom.

Most people don't realize this, because the holes are hidden behind the little switch thingy that opens and closes the drain. Water gets out through the small but not watertight gap around the assembly. See link.
-- 5th Earth, Nov 30 2007


A modified electric shower and a small pump would handle the recirculation and reheating; the built-in thermostat would be enough to regulate temperature. The filter would be pretty unpleasant, unless it was some ort of limited-use disposable cartridge..... the constant-level thing is easy-peasy.
-- 8th of 7, Dec 03 2007


Well let's assume he doesn't like wasting water...add a verticle pipe that connects to the tub down low. Put a float in the pipe that will shut off the water at a level enough below the overflow drain to prevent its use and have the float switch turn off the water and turn on a recirculating pump/heater/filter that uses a big hot tub filter and a UV light to kill bacteria. That way you could just start the tub and it would auto-fill and stay warm till you were done.
-- MisterQED, Dec 04 2007



random, halfbakery