The present invention refers to a device for obtaining heated water at a temperature less than or equal to 45°C, without contravening the behavioral requirements of the orthodox Hebraic religion.

As regards Saturday, the Hebraic religion imposes, among other things, the compliance with the two following rules :

1) hot water, during Saturday, must not be mixed with cold water, if the mixing result generates a temperature greater than 45°C;

2) a human action, during a Saturday, even if indirect, must not cause the turning on or off of electric units or of boiler fires and the like.

Prior art systems for heating water are not suitable to guarantee the compliance with such rules, since they provide neither for the final temperature check, nor for preventing heating devices from being turned on following a withdrawal of water from a tap. A simple solution to this problem could be given by a device which continuously heats running water at a temperature less than or equal to 45°C, said water being withdrawn, and possibly mixed with cold water, sending heated and unused water to be discharged. In this way, religious rules are observed, since the action of opening the tap for withdrawing hot water does not generate "a turning on or off of electric units or of boiler fires and the like", since it is always operating; moreover, mixing with cold water does not generate a mixture whose temperature is greater than 45°C.

Such solution is clearly unfeasible since energy and water consumptions would be enormous.

Alternatively, an amount of water enough for Saturdays can be heated, stored in an airtight container, and the necessary water can be withdrawn, possibly mixing it with cold water. This solution is clearly not practical, since it would be rather preferable that this water is heated in a water-heater and kept hot therein, being the container already airtight, without activating a heating device during Saturdays. However, with prior art electric or gas boilers with accumulation, this is not possible, since upon every withdrawal of hot water, there corresponds a similar amount of cold water entering the accumulating tank, this generating the automatic turning- on of the heating device, contravening the second Sabbath rule .

Documents US-A1-2009/103907 and WO-A1-98/57100 disclose devices according to the preamble of Claim 1.

The present invention solves the above problem, by providing a device for obtaining heated water at a temperature less than or equal to 45°C, without contravening the behavioral requirements of the orthodox Hebraic religion, as claimed in Claim 1.

The use of a water-heating device according to the invention allows having available water at a temperature next to but lower than 45°C without contravening the rules of the orthodox Hebraic Saturday. The device according to the invention allows obtaining this relevant result without the need, by a user, of performing particular manoeuvers .

The invention will now be described, as a non- limiting example, according to a preferred embodiment thereof and with reference to the enclosed drawings, in which:

Figures 1 (a, b, c) show a device according to the invention;

Figures 2 (a, b) show two variations of the device according to the invention;

- Figure 3 shows the heating device for keeping the water temperature constant;

Figure 4 shows a further variation of the device according to the invention;

Figure 5 shows a control device for the mixed water temperature; and

Figures 6 (a, b) show two variations of a mixing device .

In Figures 1 (a, b, c) , (1) designates a water- heating device according to the invention, adapted to obtain heated water at a temperature which is next to, but lower than 45°C, without contravening any Sabbath rule. This water-heater comprises a tank (2), whose upper part (2a) is connected, through a first pipe (3) , to a compressed air tank (4).

The tank (2) is connected, through a second pipe (5), to a thermostatic mixer (6), equipped with check valve, which in turn is connected, through a third pipe (7), to the public mains. The pipe (5) operates both as inlet duct for cold water, and as outlet duct for hot water. This second pipe (5) extends inside the tank (2) so that the water level inside the tank (2) never drops below a minimum level Lm, in order to keep the heating electric resistance always immersed, as will better specified below .

A fourth outlet pipe (8) of the thermostatic mixer (6) is the real outlet of the Sabbath water-heater (1) of the invention.

During Saturdays, the thermostatic mixer (6) has also the function of check valve, preventing an entry of cold water into the tank (2) . Under such conditions, the withdrawal of water from the tank (2), through the fourth pipe (8), is possible due to the fact that the withdrawn water volume is replaced by the compressed air which, through such first pipe (3) , flows from the compressed air tank (4) to the upper part (2a) of the water (2) .

The thermostatic mixer will be calibrated so that the final mixing temperature is equal to or less than 45°C.

To be able to operate by complying with Hebraic Saturday rules, before starting the Saturday itself, the following operations must be performed:

• pre-arranging the thermostatic mixer (6) in order to allow filling the tank (2);

• heating water contained in the tank (2) at the maximum allowed temperature;

· pressurizing air contained in the tank (4);

• restoring the check valve of the thermostatic mixer ( 6 ) .

The fact of calibrating the thermostatic mixer so that the final mixing temperature is equal to or less than 45°C allows complying with Sabbath rule 1, which forbids mixing hot water with cold water if the mixing result generates a temperature greater than 45°C. Moreover, the withdrawal of water from the thermostatic mixer (6) , through the fourth pipe (8), not making cold water enter into the tank (2), does not decrease the temperature of water contained therein, and therefore does not activate electric units or boiler fires and the like: therefore, the second Hebraic Saturday rule is observed.

According to a preferred embodiment, shown in Fig. lb, an installation is provided, in place of the thermostatic mixer (6), for a further intermediate passing container (9), having reduced sizes which, in addition to having the function of thermostatic mixer, is a water accumulation already at its temperature of use. This container (9) is connected, through the second and third pipes (5) and (7), respectively to the tank (2) and the hydraulic mains, a probe (10) being provided, which is connected to a valve (11), which constantly measures the temperature inside the container (9) and drives the valve (11) to batch the necessary amount of hot water for reaching therein a temperature next to but lower than 45°C.

According to a further preferred embodiment, shown in Fig. lc, the water-heater (1) comprises the installation of an independent tap (12), directly onto the second pipe (5) for letting out hot water at high temperature, before its entry into the thermostatic mixer (6), in order to be able to deliver boiling water for kitchen use.

The water-heater, as described and shown again in Fig. 2a, can be obtained from a traditional water-heater, extending the first pipe (3), normally used for withdrawing hot water, to connect the upper part (2a) of the tank (2) to the compressed air tank (4) and using the cold water inlet part of the second pipe (5) also for withdrawing hot water, through the devices shown in Figures 1 (a, b, c) .

According to a preferred embodiment, shown in Fig. 2b, a water-heater (la) is obtained by inserting a tank (4a) for compressed air into a further casing (13) which also contains a water tank (20) . In such case, it will be enough to connect this tank (4a) for compressed air to the upper part (20a) of the water tank (20) through the first short pipe (3a) . Also in this case, the second cold water inlet pipe (5) is also used for withdrawing hot water, through the devices shown in Figures 1 (a, b, c) .

The charge of the compressed air will be performed firstly by the same water-heater, during the filling step, and will then be completed by means of a silent mini- compressor (not shown) suitable for household use. It will be able to operate only during working days, because according to Hebraic Saturday rules, during its 25-hour period, activation and stop of electric systems are forbidden, through a human action, even if indirectly. Therefore, before beginning a Saturday, the air container will have to be completely filled and ready for use. A pressure-switch (not shown) , connected to the air container, will check its pressure only at the end of every Saturday and will activate the mini-compressor until the preset pressure is reached.

The described water-heater is capable of operating in an efficient way depending on the lowest thermal dispersion obtained. In fact, the temperature of water contained in the tank (2, 20) tends to decrease during the 24 hours of a Saturday.

Figure 3 shows a device for keeping the temperature of the water-heater, in order to compensate the heat dissipation in the environment.

The heating device has two circuits, to be used separately, for reaching and keeping the operating temperature, these circuits being activated through a switch CSF .

During working days a first circuit is activated, placing the switch CSF in position F so that a resistance RP , supplied through a transformer TR and regulated by a thermostat T , takes care of heating water. The operation of the resistance RP is preferably controlled also by a switch IG which opens if a float G detects that there is no water in the tank (2) .

What has been described is substantially the operation of the heating device of a traditional water- heater. In fact, if a withdrawal of hot water corresponds to the entry of a same volume of cold water, the mean temperature of water contained in the tank (2) drops and the thermostat T activates again the resistance RP which restores the preset temperature.

During Saturdays, a second circuit is activated, by placing said switch CSF in position S . In this way, keeping the temperature, previously reached by means of the heating element RP, is obtained through a Positive Temperature Coefficient, PTC, resistor. The heating element RP of the water-heater will be activated before starting a Saturday, until it reaches the preset temperature. After this, said PTC resistor will start operating, for keeping the previously reached temperature.

The described heating device allows keeping the reached temperature automatically, namely without any human intervention, and therefore, in spite of the activation of an electric device, the second Sabbath rule is observed.

Another method for keeping the temperature can be using the same electric resistance RP as equipment for the water-heater. This resistance however will be supplied by short pulses, next to the necessary power, or with direct current and low voltage, and regulated by means of a PTC resistor PTC calibrated at the keeping temperature, connected thereto in series or still more, to another self-regulating system, such as, for example, a digital controlled with thermocouple (not shown) . Given the small power necessary for keeping the temperature, it is also possible to use a 12-volt accumulator, of the type used in cars .

Such system has the feature of having a smaller energy consumption, with savings greater that half the energy, in comparison with traditional water-heaters. This is due to the fact that, in traditional water-heaters, a double amount of water is heated, namely hot water which is used and cold water which takes the place of this latter one when delivering, this heating being performed together with the withdrawal. This means that, at the end of a use, a superfluous amount of hot water remains, which very probably will not be used, namely an amount of water, equal to the whole volume of the tank (2, 20) for which electric energy will have to be consumed to compensate the thermal dissipation. The water-heater of the invention, instead, can be filled only partially, namely only with the necessary amount of water. In this way, at the end of its use, the water-heater will be almost empty, and therefore the whole volume of the tank (2, 20) will not have to be kept in temperature.

According to a preferred embodiment, an installation is provided for a chrono-thermostat (not shown) , in order to program the heating times. This device will be particularly useful when the contract for providing electric energy provides hour ranges in which the cost is lower. In such case, a suitable programming of turning-on times allows obtaining further savings.

According to a preferred embodiment, shown in Fig. 4, water is kept pressurized by a pump (14), which can also be of the submerged type (14a). In this case, a second pipe (5a) is provided, for filling the tank (2) . In this case, the compressor can be removed, because it is not necessary any more that the chamber (2a) is pressurized.

In case of a Saturday use, it is possible to use a centrifugal pump, suitably sized in order to continuously operate for the whole period of a Saturday. This because, the use, for example, of a pressure switch, which activates the pump operation upon opening the tap, would violate the principle according to which the human action of opening the tap triggers, as a consequence, an electric contact. The use of a pump is possible also when filling and this latter one, if suitably sized, can also provide the compressed air necessary for a Sabbath use with the consequent abolition of the compressor.

Figure 5 shows a variation of the supply of the thermostatic mixer with accumulation (9) . According to this variation, the flow of hot water in the second pipe (5) is obtained through a batching pump (15), controlled by a flow-meter (16) placed on the third pipe (7) for cold water. In this way, the batching pump (15) will circulate, through the thermostatic valve (10), the right dose of hot water inside the container/mixer (9) where mixing with cold water occurs.

Figures 6 (a, b) show two variations (9a, 9b) of the thermostatic mixer with accumulation (9) .

The first thermostatic mixer with accumulation (9a) is connected to the third pipe (7) for cold water and to the second pipe (5) for hot water, this latter one being regulated by the thermostatic valve (11) driven by the probe (10) and has its outlet (8) oriented downwards.

The probe (1) is connected to the upper part of the mixer and is interposed between the two inlets so that the valve (11) has a shorter response time.

Inside the thermostatic mixer with accumulation (9a) a small floating ball (17) is placed, which, when there is no water, closes the outlet hole (18) , in order to prevent compressed air from going out. When hot water ends, air, which is lighter, fills the upper part of the thermostatic mixer with accumulation (9a), making the water level progressively drop, so that the small ball moves on a downward path until it finds itself next to the outlet hole (18), connected to the fourth pipe (8), to be then sucked back by the flow of water and close the outlet hole (18) .

By filling again the thermostatic mixer (9a), water will make the small ball (17) float, re-opening the outlet hole (18) .

The second thermostatic mixer with accumulation (9b) has the third pipe (7) for cold water and the second pipe (5) for hot water connected in their lower parts, while the outlet (8) is placed in the top part. The block of compressed air from going out occurs by means of a float- type valve (19), which will close an outlet hole (18a) when the water level drops below the level of said outlet hole (18a) .

In the Hebraic laws for Saturdays, the use of this mixer with accumulation is very important. In a first step, filling with cold water is provided, which freely circulates, while, in the following steps, batching of hot water occurs by means of the thermostatic valve (11) . Hebraic laws in fact provide that it is hot water with progressive doses to be mixed with cold water, so that the mixture never reaches a temperature greater than 45 °C.

From the previous description, it is clear that the device of the invention allows obtaining water at a temperature next to but lower than 45°C, without performing particular manoeuvers and with the complete compliance of orthodox Hebraic Saturday rules.