Patent for Sale:

Water-Saving Mixer Tap    

New ecological faucets that recycles the cold water present in the pipes to save an average of 10 gal of water/day/house while drastically reducing the waiting time for hot water.


Homes with long plumbing running from the hot water tank to the places where the water is used can have a long wait for hot water. You turn the hot water tap on, and a minute later it's still running cold. This waiting time is uncomfortable and makes you waste +/- 10 gal of water /day/house to the sink.

To overcome the problem and to avoid user's complaints, most plumbers now adds a hot water recirculation loop that keep the water in the hot water supply pipe hot. This type of hot water circulating loop provides nearly instant hot water at the fixtures, but wastes a tremendous amount of energy : often more than 5KWh/day, an amount of energy that requires 10 gal of water to be produced at the electricity power plant due to the water-energy nexus. The hot water recirculation loop does not save any water, it changes the location of where the water is wasted.

With or without a hot water recirculation loop, in most houses, an average of more than 10 gallons of water are wasted every day to provide access to hot water.

The purpose of awater-saving mixer tap is to overcome the water wasting problem.

A new water-saving faucet has been developed - a tap that gives access to the hot water as fast as if you have a hot water recirculation loop installed, but without wasting any cold water or energy.

The water-saving mixer tap has the same look and the same functions as those of a standard faucet, but it includes an additional drain orifice and a water-saving function that permits the cold water present in the hot water pipes to escape within a few seconds, thus making the hot water available very quickly.

How it works :

1. Push the lever down until it locks. Within a few seconds the cold water present in the hot water pipes is directed, via the drain pipe, to an expansion tank.

2. When the hot water reaches the faucet it causes the expansion of a thermostatic element that unlocks the lever so it comes back automatically to the closed position.

3. The faucet can then be used in a conventional manner, the hot water is available at opening.

The cold water that was originally present in the hot water pipes has been sent to the expansion tank, it will automatically be reused in priority at the next demand for cold water, thanks to a priority valve installed in the cold water circuit.

The shower faucet and shower head with a downstream loop-back will even allow you to enter the shower before opening the tap with no risk of receiving a single drop of cold water, with zero water waste and zero energy waste, for more comfort and a strict minimum water consumption.

For large installations such as hotels, one or several "thermostatic water separator" can be added, so the waiting time for hot water remains very short regardless the length of the pipes.

The EPA report that "Studies have shown that the average home wastes more than 3,650 gallons of water per year waiting for hot water to arrive at the point of use." (10 gallons, per day, per home). Information source:

The average water saving is 10 gallons of water a day, per househould, plus no wasted energy.

Primary Application of the Technology

For all houses, apartments, office.
For people who care about the ecology and the conservation of resources of the planet

The Problem Solved by the Technology

Problem exist in all the medium and large houses. The hot water supply line in a home carries hot water from the water heater to the various sinks and baths throughout the house. In a home without recirculation, when you turn on a hot water faucet, all the water sitting in the supply lines has to pass through the pipes before hot water from the tank reaches the faucet. As a result, you have a double problem of wasting gallons of water down the sink, and an annoying wait time for the hot water to arrive.

Some "water saving tips" recommend installing a "hot water recirculation loop" so you no longer see the water flowing down the sink and you will erroneously believe you do not waste any water. The hot water recirculation loop, even with a timer, will save the water within your home, but it waste a tremendous amount of energy because of the water-energy nexus. Information source: It requires 2 gallons of water to produce 1 KWh of electricity in the production plant.

"Domestic hot water can represent up to 40% of energy consumption in a residential building, house or building, and 30% to 50% of the heat produced during the generation of collective hot water disappears into the distribution loop". Information source:

In summer, you are in a crazy situation, you consume the energy to keep the hot water loop at high temperature and it works as a radiator in the wall (+/- 5 KWh/day) while at the same time the air conditioning consumes electricity to lower the temperature in the house (> 5 KWh/day), so more than 10KWh/day is wasted for the comfort of reducing the waiting time for hot water. The hot water recirculation loop waste in an hidden manner, it is a huge amount of energy, and considering the amount of water necessary to produce that energy, it results in more water wastage than without the hot water recirculation loop.

The hot water recirculation loop doe not save water because more water is wasted at the electrical power plant. With or without a hot water recirculation loop, you waste an average of 10 gal of water/day/house, and you waste a huge amount of energy if a hot water recirculation loop is installed.

How the Technology Solves the Problem

A water-saving mixer tap provides acces to the hot water within a few seconds, without wasting any water and any energy at all. It also makes more attractive the installation of other water-saving devices. The waiting time for hot water is critical, sometimes it is more than one minute. When you install a new water-saving device as a faucet aerator or a low-flow shower head, you will divide the water flow by 2, but you will notice that you also double the waiting time for hot water, and it is likely that it will discourage you. The water-saving mixer tap makes the hot water available as fast as if you have a hot water recirculation loop and, since the cold water is exhausted via the drain port, the addition of a water-saving orifice does not affect the waiting time for hot water. A water-saving mixer tap can be used with several circuitry configurations to reuse the cold water. Click tell me more for details about the different circuitry configurations that are available and to see a demo video.

Models of water-saving mixer taps with a thermostatic temperature control have also been developed. For the shower application, the thermostatic water-saving mixer tap will control a loopback circuitry via the shower head, so you can enter the shower before opening the tap with no risk to receive a single drop of cold water, without any water or energy wastage and for more comfort and a strict minimum water consumption.

Competitive Advantage

The "Demand-Initiated Recirculation System with a button activation" that are available on the market could possibly be considered as competition to some people. They connect the hot water pipe to the cold water pipe to reduce the water and energy wasted while waiting for hot water. This system is not pleasant to use because you have to actuate the button and then wait minutes before you get the hot water.

Another disadvantage is that you have lukewarm water in the cold water pipe that is sometimes a problem, for example in the kitchen you want to get fresh water to drink and wash salad etc. This option is also much more difficult to implement and more expensive.

The seller may consider selling these patents individually.

Patent Summary

U.S. Patent Classes & Classifications Covered in this listing:

Class 137: Fluid Handling

Fluid material handling, and takes processes, systems, combinations, subcombinations and certain elements pertaining thereto not otherwise classified. Fluid materials include gas and liquids primarily, but the handling of other flowable materials, as fluent granular solids, is also found. Handling of fluent material by flow, as by confining, directing, causing and/or controlling the flow, and includes making the material available for flow or separating a smaller from a larger body of fluid material, as by tanks, containers, receivers, traps, etc., or pipes or conduits, with or without siphons, pumps, pressure or displacing fluids or other flow imparting means.