ELECTRIC WATER HEATER Russian patent published in 1998 - IPC

FIELD: heating of water for domestic needs. SUBSTANCE: electric water heater incorporates body 1 made from heat insulation material with heat conductive upper cover 8 in which tubular U-shaped electric heating elements 2, 3, 4 with leads 7 located in cover 8 of body 1 are placed, U-shaped pipe-line 10 to feed cold water with pressure transducer 11 positioned together with knee of pipe-line not below upper part of heat transfer surface of electric heating elements 2, 3, 4. Pipe-line 10 to feed cold water is joined to lower part of body 1, pipe-line 23 to tap away heated water is connected to upper cover 8 of body 1 where local hydraulic resistance 22 and thermal regulator 17 of water are installed. Transducer of regulator 17 is confined in heat conductive enclosure that is joined to upper cover 8 with possibility of thermal contact. Height of enclosure does not exceed value 2,5λF_s,, where λ is thermal conductivity of material of enclosure; F_s is area of cross-section of side wall of body 1. There are also mounted safety thermal switch 24 installed in upper cover 8 and placed between A.C. network and power supply buses of electric water heater and control unit. Control unit has button element setting power of switched on electric heating elements with buttons 27 and 28. One stroke of button 27 causes increase of power in switched on electric heating elements, depression of button 28 results in decrease of this power. Control unit also includes limiter of maximum power. Buttons 27 and 28 are connected through resistors to power supply source and through pulse formers first one - to first input of first NOT-OR gate, second one through NOT gate - to second input of OR gate. First input of OR gate is connected to output of NOT-OR gate and output - to counting input of binary reversible counter which reverse input is connected to output of first NOT-OR gate and input of setting of initial state is coupled to output of initial setting unit of counter. EFFECT: increased reliability and improved user's qualities. 10 cl, 14 dwg