Patent ID: 7930937

Claim:
A detection device for measuring the quantity of hot water remaining inside a storage reservoir and more particularly inside a tank ( 2 ) of a water heater ( 3 , 30 ), which device comprises: a capillary tube ( 10 ) containing a heat-carrying fluid which is placed either inside, or outside the tank ( 2 ) of the water heater ( 3 , 30 ); and an indicator device ( 12 ) coupled to said capillary tube ( 10 ), said indicator device ( 12 ) comprising an amplifying device ( 15 ) disposed outside said tank ( 2 ) and making it possible to transmit under the effect of the expansion of the fluid contained in the capillary tube ( 10 ) either a motion to a member ( 16 ), or a variation in resistance to an electronic system ( 24 , 26 ) in such a way as to continuously indicate the quantity of hot water available remaining in the tank ( 2 ) of the water heater ( 3 , 30 ), wherein the capillary tube ( 10 ) is placed outside the tank ( 2 ) of the water heater ( 3 , 30 ), underlying a layer of a thermal insulant ( 5 ) and cemented against and over the entire height of the vertical external face ( 14 ) of said tank so as to allow it to be coupled to the indicator device ( 12 ).