The present invention patent refers to new improvements introduced in central water heaters of the type utilised to supply current hot water to various points of use in a residential or commercial building. It allows that water be supplied at a predetermined temperature, to the kitchen, toilets and bathrooms of the building.

One of the advantages brought to our day-to-day life through technological development has been the ability of obtaining hot water in our own houses, it only being necessary to open a valve or a tap to gain access to this important item of comfort.

Basically, the heating of the water that runs through the hydraulic installation of a building can be done at each point of use, by means of a tankless electric water heater or through an accumulation system, in which a pre-determined volume of water enters into the shell of an electric or gas heater and the water is pre-heated and stored till a valve or a tap is opened at one of the points of use connected to the hot water distribution piping linked to the outlet of the mentioned heater.

From the thermal output point of view, the tankless heaters are unsurpassable, as they transform 98.7% of electric energy into heat that is transmitted to the water.

As these units are installed at the points of use, practically there are no heat losses. This does not happen with the boilers and other accumulation systems.

As a matter of fact, not only do these register heat losses through their own shells, no matter how good the insulation is, but

there also occur thermal losses as the water flows through the piping to the point where it is to be used.

Additionally, the installation and maintenance cost of such central heaters is very high, especially when compared to the operational cost of the tankless heaters.

On the other hand, with regard to the aspect which refers to consumption peaks, the tankless heaters have the disadvantage of a very high power consumption, and as such in the case of coinciding demands, as is the case at certain times of the day, the use of the mentioned heaters puts at risk the capacity of the power supply from the concessionaires.

In view of the above, and due to the circumstances which involve the present scarcity of power supply, there is a clear trend in favour of the use of accumulation heating systems.

The inventor, being aware of this scenario and being dissatisfied with the performance of the existing central heaters, both the gas and the electric heaters, developed detailed studies to find an alternative which would lower the costs and increase the efficiency of this type of heater.

As a result of his patient work, he has conceived an original electric heater, whose cost is low and is very simple and does not require the utilisation of the usual coils.

The object of this patent is therefore a new improvement for electric accumulation systems. This type of heater has a shell with two pipe projections at opposite ends that are threaded. These represent respectively the inlet and the outlet. The area adjacent to the inlet has one or two magnetron type valves fitted on to the inlet pipe projection, these exchange heat with the water that flows into the unit, pre-heating

it and cooling the mentioned valves. The internal side of the shell has a cylindrical chamber and the water that flows into the unit passes through it. It is positioned in such a way as to be exposed to the microwaves generated by the above-mentioned valves. The mentioned chamber is fitted with a thermistor which issues a signal corresponding to the temperature of the water, which is relayed to a microprocessor installed on the control circuit board. This board is connected to an external panel that has an alphanumeric display, an "on/off"button and a keyboard that enables the user to manually adjust the water to the desired temperature. The microprocessor is connected to a current variation device which feeds the magnetron valves, so as to intensify or reduce the emission of microwaves and thus keep the water at the selected temperature, based on the signal received from the thermistor.

This configuration results in a highly efficient heater, with programmable temperature for the water supply, which is automatically kept at the temperature selected on the keyboard.

For clarification and a better understanding of this new type of equipment, the mentioned configuration is shown in the attached drawings, i. e.:- Drawing 1-lateral view of a heater built in accordance with this patent ; Drawing 2-Schematic drawing of the operation of this new heater; Drawing 3-Front view of the heater control panel.

In accordance with the drawings and their details, the new aspects consist of new and original improvements introduced in electric accumulation heaters, of the type which has a shell (1)

provided with two pipe projections (2) and (3) at opposite ends and threaded (4) and (5), representing respectively the water inlet and outlet, the area adjacent to the water inlet (2) has one or two valves (6) of the magnetron type, which are fitted on the inlet pipe projection, in such a way as to exchange heat with the water which flows into the unit, pre-heating it and cooling the mentioned valves, the internal side of the shell shows a cylindrical chamber (7) which is crossed by the water which flows into the unit and it is positioned in such a way as to be exposed to the microwaves generated by the aforementioned valves ; the said chamber is provided with a thermistor (8) which issues a signal corresponding to the water temperature, and that signal is relayed to a microprocessor (9) installed on a control circuit board (10), this board is connected to an external panel (11) which has an alphanumeric display (12), an"on/off"button (13) and a keyboard (14) which enables the user to manually adjust the water to the desired temperature, the microprocessor (9) is connected to a current variation device (15) which feeds the magnetron valves (6) so as to intensify or reduce the emission of microwaves and thus keep the water at the selected temperature, based on the signal received from the thermistor (8).

Evidently, one can conceive several heaters similar to the heater described herein, differing only with regard to shape, measurements, proportions, materials and other aspects of lesser importance. Such systems, however, shall remain indissolubly linked to the spirit and the scope of this patent.