EP3182032A1 - Flat domestic water heater with immersed indirect heating elements - Google Patents

Abstract

The invention relates to a flat water heater for domestic use (10), characterized in that it comprises at least two tanks (12, 14) each treated with an anti-corrosion coating or each made of an anti-corrosion material and each intended to contain water to be heated, each tank incorporating at least one electrical resistance disposed in a sealed sleeve (18,20) treated with an anti-corrosion coating or made of an anti-corrosion material and intended to be immersed in the water of the tank.

Description

The invention relates to a flat water heater for domestic use and a method of implementation.

In dwellings, especially flats, the water heaters are installed in the living space.

Such a water heater generally incorporates a shielded electrical resistance immersed in each tank of the water heater. This type of resistance has a high charge rate, which results in a high temperature of the wall of the resistor which is in direct contact with the water.

Therefore, when the water heater is turned on to produce hot water, for example in the evening, a phenomenon of heating occurs on the surface of the hot wall of each resistance. This phenomenon generates a noise (surface boiling) that is likely to interfere with the occupants of the house equipped with such a water heater, especially when the noise occurs in the evening or night. This noise is all the more important as there are two resistors in the water heater.

Moreover, the known phenomenon of scaling of the resistance is aggravated by the high temperature of the surface of the wall of the resistor.

In view of the foregoing it would therefore be particularly useful to design a flat water heater for domestic use which limits the noise associated with heating water and reduces the phenomenon of scaling.

The invention thus relates to a water heater for domestic use, characterized in that it comprises at least two tanks each treated with an anti-corrosion coating or each made of an anti-corrosion material and each intended to contain water. water to be heated, each tank incorporating at least one electrical resistance arranged in a sleeve treated with an anti-corrosion coating or made of an anti-corrosion material correspondingly with the tank and intended to be immersed in the water of the tank , the sheath being mounted in a sealed manner with the tank, said at least one electrical resistance being surrounded by air inside the sheath such that the water of the tank is heated indirectly by radiation of said at least one electrical resistance on the sheath.

The water contained in the tank is thus heated indirectly by radiation of the electrical resistance on the sheath which envelopes it via the air surrounding the resistor. As air is used for radiant heating and not a specific gas, it is not necessary to provide a seal of the inside of the sleeve relative to the outside of the tank. The sheath is sealed between the inside of the tank and the sheath to prevent the passage of water between the sheath and the tank, for example the bottom of the tank if the sheath is mounted on the bottom directly or indirectly. The ambient air can indeed flow between the inside of the sheath and the outside of the tank, for example, the part located below the tank. Therefore, the maintenance on the electrical resistance or resistors is particularly simple. It will be noted that the sheath can be fixed directly in a sealed manner on the tank (eg the bottom or the edge of the tank) or sealingly attached to an intermediate piece which, in turn, is fixed directly in a sealed manner on the tank . The arrangement of the resistance in a sheath has the effect of limiting the value of the temperature on the outer surface of the sleeve in contact with the water of the tank. The noise due to the phenomenon of calefaction between the electrical resistance and the water of the tank is thus reduced.

In addition, the fact of having the same material for the tank and the sheath (s) containing the resistor (s) (the inner lining of the tank is enamel or another coating) corrosion deposited on steel and the sheath is externally coated with enamel or other anti-corrosion coating, ie the tank is made of the same anti-corrosion material as the sleeve and which may be a metal or not) avoids electric cell phenomena that accelerate corrosion. Thus, the sacrificial anode of protection against corrosion, when present in the tank (optional), is consumed less quickly than in the presence of different materials.

The tanks are generally cylindrical and arranged side by side.

Such a water heater is said to be "flat" in the sense that one of its two dimensions (the two dimensions are taken in a view perpendicular to the axis of the rolls) is smaller than the other which represents the dimension according to which the two tanks are arranged side by side. The smaller size of the water heater usually corresponds to that of one of the two tanks (diameter of one cylinder), while the other dimension of the water heater generally corresponds to the sum of the two tanks, plus a gap between the two tanks. The cumulative volume of the two tanks of the water heater would be contained in a cylindrical tank of larger dimensions (larger diameter) than those of each of the two tanks taken in a view perpendicular to the axis of the cylinders. The water heater produced by the arrangement of the two tanks (or more) side by side appears as flattened (in a plane perpendicular to the axis of the cylinders) relative to the large tank of the cumulative volume. Such a water heater geometry is particularly suitable for installation in a domestic premises where the living space is sometimes reduced and cramped. Because of such an implementation, the noise reduction aspect is all the more important. Note that the two tanks do not necessarily have the volume.

• le fourreau contenant la résistance électrique est disposé de manière inclinée par rapport à au moins une paroi de la cuve ; cette disposition favorise l'agencement du chauffe-eau dans de multiples positions, notamment en position horizontale ou verticale ; lorsque le chauffe-eau est disposé horizontalement, il est positionné de manière à ce que le fourreau de chaque cuve soit incliné vers le bas afin de chauffer l'eau se trouvant au fond du chauffe-eau dans cette position, c'est-à-dire l'eau se trouvant le long d'une des parois du chauffe-eau ;
• le fourreau est incliné par rapport à un axe définissant la plus grande dimension de la cuve (généralement l'axe du cylindre ou de la partie cylindrique, appelée virole, de la cuve) d'un angle compris entre 5 et 15 ;
• chaque résistance électrique est en céramique ;
• chaque résistance électrique est de type blindée, plus particulièrement, de type cartouche blindée ;
• les fourreaux et les cuves sont en acier émaillé ; un fourreau en acier émaillé possède une puissance surfacique réduite (ex : 4W/cm2) par rapport à celle d'une résistance blindée en contact direct avec l'eau (ex : 8 à 10 W/cm2) ; l'entartrage est de ce fait réduit ;
• chaque cuve intègre, lorsque ladite cuve est traitée avec un revêtement anti-corrosion (notamment de l'émail et la cuve et le fourreau sont alors en acier émaillé), au moins une anode sacrificielle de protection additionnelle contre la corrosion et qui est destinée à être immergée dans l'eau contenue dans la cuve ;
• ladite au moins une anode de chaque cuve est montée sur le fourreau ou sur ladite cuve ;
• la puissance électrique de chaque résistance électrique est comprise entre 500 et 3000W ; de telles valeurs sont particulièrement adaptées pour des chauffe-eaux à usage domestique implantés dans des habitations ; la résistance électrique de chacune des cuves peut être différente ; par exemple, la résistance électrique de la cuve située immédiatement en amont du circuit (ou de la conduite) de distribution d'eau chaude (la distribution d'eau chaude est effectuée dans un local où est implanté le chauffe-eau) a une puissance électrique supérieure à celle de la résistance de l'autre cuve, ce qui apporte un certain confort d'utilisation puisque l'eau chaude distribuée est d'abord celle chauffée dans la cuve située immédiatement en amont du circuit de distribution d'eau chaude ;
• le volume cumulé desdites au moins deux cuves est compris entre 20 et 300L ; de telles valeurs sont particulièrement adaptées pour des chauffe-eaux à usage domestique implantés dans des habitations.

According to other possible features of the invention:

• the sleeve containing the electrical resistance is inclined with respect to at least one wall of the tank; this arrangement promotes the arrangement of the water heater in multiple positions, including horizontal or vertical position; when the water heater is disposed horizontally, it is positioned so that the sheath of each tank is inclined downward to heat the water at the bottom of the water heater in this position, that is to say the water located along one of the walls of the water heater;
• the sleeve is inclined with respect to an axis defining the largest dimension of the tank (generally the axis of the cylinder or of the cylindrical part, called the shell, of the tank) by an angle of between 5 and 15;
• each electrical resistance is ceramic;
• each electrical resistance is of the shielded type, more particularly of the shielded cartridge type;
• the sheaths and vats are enamelled steel; an enamelled steel sheath has a reduced surface power (ex: 4W / cm2) compared to a shielded resistor in direct contact with water (eg 8 to 10 W / cm2); scaling is thereby reduced;
• each tank integrates, when said tank is treated with an anti-corrosion coating (in particular enamel and the tank and the sheath are then in enamelled steel), at least one sacrificial anode of additional protection against corrosion and which is intended for be immersed in the water contained in the tank;
• said at least one anode of each tank is mounted on the sheath or on said tank;
• the electrical power of each electrical resistance is between 500 and 3000W; such values are particularly suitable for domestic water heaters installed in dwellings; the electrical resistance of each of the tanks may be different; for example, the electrical resistance of the tank located immediately upstream of the hot water distribution circuit (or pipe) (the hot water distribution is carried out in a room where the water heater is located) has a power electrical superior to that of the resistance of the other tank, which provides a certain comfort of use since the hot water dispensed is first that heated in the tank located immediately upstream of the hot water distribution circuit;
• the cumulative volume of said at least two tanks is between 20 and 300L; such values are particularly suitable for water heaters for domestic use located in homes.

The invention also relates to a method of implementing a water heater as briefly described above. According to this method, the same water heating temperature set point is applied to each of the tanks. Such a method limits thermal losses and is more economical than a method that would apply temperature setpoints different from one tank to another. In addition, it avoids the discomfort that would be related to the use of volumes of water heated to different temperatures. This is particularly the case with a shower when the first volume heated to a first temperature is consumed and the user then receives the heated water at the second temperature.

• la figure 1 est une vue schématique générale d'un chauffe-eau plat selon un mode de réalisation de l'invention ;
• la figure 2a est une vue schématique agrandie de la partie basse d'une des deux cuves du chauffe-eau de la figure 1 ;
• la figure 2b est une vue agrandie d'un montage possible du fourreau et de la résistance par rapport à la cuve de la figure 2a;
• les figures 3a-b sont des vues schématiques respectives d'un chauffe-eau plat selon d'autres modes de réalisation de l'invention ;
• les figures 4a-b illustrent de manière très schématique deux modes de réalisation possibles pour l'agencement d'un fourreau par rapport à une cuve de chauffe-eau.

Other features and advantages will become apparent from the following description, given solely by way of nonlimiting example and with reference to the appended drawings, in which:

• the figure 1 is a general schematic view of a flat water heater according to one embodiment of the invention;
• the figure 2a is an enlarged schematic view of the lower part of one of the two tanks of the water heater of the figure 1 ;
• the figure 2b is an enlarged view of a possible assembly of the sleeve and the resistance with respect to the tank of the figure 2a ;
• the Figures 3a-b are schematic views respectively of a flat water heater according to other embodiments of the invention;
• the Figures 4a-b illustrate very schematically two possible embodiments for the arrangement of a sheath with respect to a tank water heater.

As represented in figure 1 and generally designated by the reference denoted 10, a flat water heater comprises two tanks 12 and 14 interconnected by a conduit 16. The two tanks arranged side by side thus define the largest dimension (longitudinal dimension) of the heater water. The tanks are filled with water and serve as reservoirs for storing water and heating it. The tanks are generally cylindrical, the axis of the cylinder corresponding with the vertical on the figure 1 .

In the illustrated example, the cold water (EF) arrives on the right in the tank 12, then passes into the tank 14 until the water fills the two tanks. The water is heated in each of these tanks and leaves the left tank 14 (EC), immediately upstream of a distribution circuit (not shown), to be then distributed to a user in need of hot water (room bath, kitchen ...).

Each tank is treated with an anti-corrosion coating on the inside of the tank and, for example, is made of enamelled steel. Each tank comprises inside a sheath including an electrical resistor 18 (tank 12), 20 (tank 14), a sacrificial anode of additional protection against corrosion 19 (tank 12), 21 (tank 14). Each electrical resistance is disposed inside a sleeve also made of enamelled steel (at least on its outer face intended to be in contact with the water of the tank) and which is mounted in a sealed manner (screw-to -vis water) here on the bottom of the tank. Each anode is disposed in contact with the sheath of the tank in question and, here, is mounted on the sheath. Each anode is thus for example arranged in a centralized position between the top and bottom of the tank. According to a variant not shown, each anode is mounted in a sealed manner on the bottom of the tank.

Each tank may also comprise a sheath for thermostat 22 (tank 12), 24 (tank 14), disposed next to each sheath. On the figure 1 is shown the electrical / electronic part of the thermostat 25 (tank 12), 26 (tank 14).

The figure 2a illustrates in an enlarged manner the lower part of the tank 12 (the same arrangement and the same description apply to the tank 14) which comprises a bottom 12a to which is fixed from below, for example by screwing, a base 12b.

The sheath 18a for enclosing the electrical resistance and to act as an interface with the water of the tank is mounted in a fixed and sealed manner inside the tank, extending from the bottom thereof as a glove finger. The sleeve 18a is for example sealed welded to an intermediate piece, such as a flange 28, which is itself sealingly attached to the bottom of the tank from below. The figure 2b illustrates a possibility of tight fitting. The sleeve 18a is for example welded on its outer surface, near its open end 18a1, on a first face (facing downwards) of the piece 28. The piece 28 is sealingly attached against the bottom 12a of the bowl from below said bottom (the second opposite face of the part 28 is in contact with the bottom), for example, by a sealed screwing. Fasteners 29a, 29b shown in dashed lines represent the tight screwing on the tank. The sheath 18a is shown inclined but may adopt a straight position in another embodiment. The resistor 18b is inserted from below into the sleeve, via its open end 18a1 and is held in the sleeve, for example, by a fastening member attached to the part 28. The resistor 18b is shown with a shoulder external to the sheath, but other forms of resistance can be envisaged. As shown on the figure 2b a space e is present between the inner face of the sheath and the resistor and air is present in this space surrounding the resistor.

The resistor 18b is thus disposed inside the tank but without being in direct contact with the water since it is housed in a sheath, which greatly limits its scaling.

The sheath 22 of the thermostat serves as a housing for a probe or capillary 27 which is connected to the electrical / electronic part 25 (electrical contacts).

The electrical resistance 18b and the electrical / electronic part 25 of the thermostat are for example mounted on the flange 28 disposed under the bottom 12a, inside the base 12b. The sheath and its resistance, the anode which is mounted on the sheath and the sheath of the thermostat with its probe are arranged in a slightly inclined manner (for the sake of simplification the anodes, sheaths and thermostat sheaths are not represented inclined on the figure 1 but they are). This arrangement allows, in the horizontal position of the tank, to heat the water located in the lower part of the tank, on the side towards which the sleeve, the anode and the thermostat sheath are inclined.

According to a variant not shown, the anodes, the sleeves and the thermostat sheaths are not inclined.

The electrical / electronic part 25 of the thermostat and the electrical resistance 18b are connected so that the heating of the water in the tank by the resistance is controlled by the operation of the thermostat and the set temperature of the latter. The temperature of the water in the tank is thus regulated very simply. The power supply is not shown here for the sake of clarity.

The electrical resistance 18b heats the wall of the sleeve 18a by radiation via the air surrounding the resistor in the sleeve and the The temperature of this wall is therefore lower than if the resistance was in direct contact with the water. The bubbling noise due to the buildup of water on the outer surface of the sleeve is therefore lower. This is advantageous in terms of auditory comfort when the water heater is installed in a living room of a house (kitchen, bathroom ...), especially near a bedroom and not in a garage or a home. cellar.

In addition, the temperature on the surface of the sheath being lower, the charge rate is reduced and scaling is thus limited (the scale takes longer to form and the scale thickness is reduced.

Using the same material for the wall of the tank and that of the sleeve avoids the phenomena of electric battery, which reduces the wear of the sacrificial anode over time.

According to an alternative embodiment, the tank and the sheath of each tank are made of stainless steel.

In case of problems encountered on one or both of the electrical resistances (eg malfunction or simple maintenance operation) it is not necessary to drain the tank and / or tanks concerned since it is sufficient to remove it. its sheath, for example after having removed or unhooked the attachment member described above in relation to the figure 2b ..

By way of example, a sacrificial magnesium anode is consumed half as fast as in the case where a shielded resistor is placed directly in contact with water.

For example, the electrical resistance is ceramic (eg soapstone).

Alternatively, the resistor is of the shielded type.

For example, the sacrificial anode 19 is magnesium.

It will be noted that the resistances may be identical or different from one tank to another. The electrical power of each resistor is between 500 and 3000W and the cumulative volume of the two tanks is between 20 and 300L. By way of example, the electrical power of the resistor closest to the distribution circuit is 2250W and for the other tank, the electrical power of the resistor is 1000W and the volume of each tank is equal to 40L.

The heating of the water in the tanks is for example carried out with the same temperature set point in the thermostats. Such an implementation of the water heater described above (with the two tanks in series) avoids the discomfort under the shower compared to the situation where the temperature setpoints vary from one tank to another. This is particularly the case when the temperature set point of the tank 12 is greater than that of the tank 14 of the tank. figure 1 .

In addition, the water heater may have more than two tanks in series depending on the intended applications.

The Figures 3a and 3b illustrate several modes of installation of a multi-position water heater 30 in which the sleeve housing the electrical resistance and the latter, as well as the additional protective anode and the thermostat sheath are arranged in an inclined manner to the inside each tank. On the figure 3a the water heater 30 is shown in vertical installed position while on the figure 3b the same water heater is arranged horizontally.

The water heater 30 comprises two tanks 32, 34 interconnected by a tube 36 and in each of which are arranged a sleeve 32a (tank 32), 34a (tank 34), housing an internal electrical resistance, not shown, a sacrificial anode 32b ( tank 32), 34b (tank 34), and a thermostat sheath 32c (tank 32), 34c (tank 34).

As shown on the figure 3a the sheaths, anodes and sheaths each have the same inclination (angle a) of a few degrees with respect to the vertical axis Z. The angle of inclination a is for example between 5 and 15 °, and for example is equal to at 8 °. According to a variant not shown, the anodes may have an orientation different from that of the sleeves on which they are mounted, for example to adapt to the internal configuration of the tank.

On the figure 3b , the heater 30 is installed in a horizontal position. The tanks 32 and 34 are horizontal and the sleeves, anodes and thermostat sheaths are inclined downwards along the angle a with respect to the horizontal axis X. This arrangement makes it possible to heat the water which is arranged in the lower part of each tank, near the bottom wall 32d, 34d.

The figure 4a illustrates very schematically and partially a possible assembly of a sleeve 40 in a tank 42 of water heater. The other tank or the other tanks of the flat water heater are not shown for the sake of simplification but may include the same arrangement.

The sheath 40 is mounted sealingly directly, for example by welding, on the shell 44 located above the bottom 46 and is inclined towards said bottom to heat the water therein. The electrical resistance arranged inside the sheath is not represented for the sake of simplicity, as are the various components necessary for the operation of the assembly. According to a variant not shown, the mounting of the sleeve can be achieved through an intermediate piece.

The figure 4b illustrates very schematically and partially a possible assembly of a sleeve 50 in a tank 52 of water heater. The other tank or the other tanks of the flat water heater are not shown for the sake of simplification but may include the same arrangement.

The sheath 50 is mounted sealingly directly, for example by welding, on the bottom 54 located below the ferrule 56.

Claims (12)

Domestic water heater (10; 30), characterized in that it comprises at least two tanks (12, 14; 32, 34) each treated with an anti-corrosion coating or each made of an anti-corrosion material and each intended to contain water to be heated, each tank incorporating at least one electrical resistance (18b) disposed in a sleeve (18, 20; 32a, 34a) treated with an anti-corrosion coating or made of an anti-corrosion material correspondingly with the tank and intended to be immersed in the water of the tank, the sheath being mounted in a sealed manner with the tank, said at least one electrical resistance being surrounded by air inside the sheath of such that the water of the tank is indirectly heated by radiation of said at least one electrical resistance on the sheath. Water heater according to claim 1, characterized in that the sleeve (18, 20; 32a, 34a) containing the electrical resistance (18b) is inclined with respect to at least one wall of the tank. Water heater according to claim 2, characterized in that the sheath is inclined with respect to an axis defining the largest dimension of the vessel by an angle of between 5 and 15 °. Water heater according to one of claims 1 to 3, characterized in that each electrical resistance is ceramic. Water heater according to one of claims 1 to 4, characterized in that each electrical resistance is of the shielded type. Water heater according to claim 5, characterized in that each electrical resistance is of the shielded cartridge type. Water heater according to one of claims 1 to 6, characterized in that the sleeves and the tanks are enamelled steel. Water heater according to one of claims 1 to 7, characterized in that each tank incorporates, when said tank is treated with an anti-corrosion coating, at least one sacrificial anode of additional protection against corrosion (19, 21; 32a , 34a) and which is intended to be immersed in the water contained in the tank. Water heater according to claim 8, characterized in that said at least one anode (19, 21; 32a, 34a) of each tank is mounted on the sheath or on said tank. Water heater according to one of claims 1 to 9, characterized in that the electrical power of each electrical resistance is between 500 and 3000W. Water heater according to one of claims 1 to 10, characterized in that the cumulative volume of said at least two tanks is between 20 and 300L. A method of operating a water heater (10; 30) according to one of claims 1 to 11, characterized in that a same heating temperature set point is applied to each of the tanks.

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