EP0184491A1 - Water heater - Google Patents

Abstract

The present invention relates to a water heater of the type comprising a reservoir with a hollow body comprising pipe connection pieces and a heating element. According to the invention, the hollow body (1) is made at least partially from a material which is in particular metal and capable of being moulded, preferably in a mould or under pressure with its lead- ins and possibly remains rough in the finished state. The invention finds application in particular in household heaters for domestic use for the supply of domestic hot water. <IMAGE>

Description

The present invention generally relates to apparatus for producing hot water and essentially relates to a device for producing hot water, in particular of the household type for domestic use, such as a water heater, distributor or bath heater for the supply of 'hot water.

In the apparatuses for producing hot water, already known, there are devices known as heating balloons, for example closed under pressure with or without accumulation, comprising either a heat-insulated tank, or a tank not or only slightly thermally insulated and a body of heater in which energy, notably chemical or electrical energy, is transformed into heat transmitted to the liquid to be heated.

The reservoir, usually in the form of a cylindrical-spherical shell, is generally made of steel and comprises a cylindrical ferrule made of rolled sheet metal, joined welded, and assembled by welding at its ends respectively to two curved ends of pressed or repelled sheet metal to which welds are welded. of piping.

On the other hand, in especially electric water heaters, the heat generator or heating element is generally constituted by electrical resistors forming either immersion heater, that is to say immersed in water of the reservoir so as to be in permanent direct physical contact therewith, ie barrel element mounted in an attached thermally conductive sheath, projecting inside the reservoir. Furthermore, thermal control instruments such as a thermometer, thermostat or the like also immerse either directly in the water by their thermosensitive part forming a probe, or in an attached thermally conductive sheath projecting inside the tank.

However, such known hot water production devices have various drawbacks. First, the manufacture of the tank is relatively slow and expensive.

In addition, there is a risk of corrosion of the welds in particular due to homogeneity defects.

On the other hand, the presence of roughness on the inner wall surface entails a risk of catching and retaining inorganic and organic particles coming from sanitary water.

Furthermore, between the metal parts of different nature present in the tank, harmful phenomena of electrolytic corrosion occur.

Finally, there is a risk of acid corrosion or clogging by scaling of the heating element, leading to a danger of it breaking.

The object of the present invention is to eliminate the aforementioned drawbacks by providing a device for producing hot water which is simple in construction and structure, which is quick and economical to manufacture, and which is low and easy to maintain.

The solution proposed by the present invention consists of a device for producing hot water of the type comprising a hollow body tank comprising pipe connection pipes and a heating body, characterized in that said hollow body is produced at least partially in a particularly metallic material capable of being molded, preferably in a shell or under pressure with its wall bushings and possibly remains raw in the finished state.

Thus, the manufacture of such a hollow body is relatively easy, and less expensive than in the case of known tanks because it does not require any additional work of forming, welding, or formation of the wall bushings and possibly d 'machining. In addition, the absence of welding eliminates the correlative risk of corrosion.

Advantageously, the material capable of being molded above has good heat-conducting properties, and is preferably capable of being surface oxidized during molding to form a protective skin.

Such a material is for example a foundry aluminum alloy.

According to another characteristic of the invention, the heating body is constituted by a block made of a thermally conductive material preferably similar or identical to that of the aforementioned hollow body in which the heating element such as electrical resistance is embedded and which is removably attached. and fixed in direct heat-conducting contact to the external wall of said hollow body.

According to yet another characteristic of the invention, the heating element is preferably housed removably in a blind cavity of the wall of the reservoir projecting towards the interior thereof.

Thus, thanks to the good thermal conductivity of the material of the tank, the water is heated indirectly by conduction and / or convection through the wall of the tank and the fact that the heating element is completely isolated or separated from any direct physical contact. with water, eliminates corrosion and clogging phenomena, and therefore any risk of failure for these causes.

According to yet another characteristic of the invention, the heating element is molded into the mass of the tank, either in a concentrated manner at a local location, or in a manner distributed at several points on the wall of the tank. This allows heating reheating by stage particularly useful in case of need to use only a fraction of the water capacity of the tank.

According to another particularly advantageous characteristic of the invention, in each aforementioned wall crossing is mounted, for example removably, a tube made of a dielectric material and which is fixed to said wall crossing by elements of dielectric material. This avoids any risk of electrolytic corrosion between the different parts present in the tank.

• - la figure 1 est une vue en coupe transversale d'un premier mode de réalisation du dispositif de production d'eau chaude selon l'invention ;
• - la figure 2 est une vue semblable à la figure 1 d'un second mode de réalisation de la présente invention ;
• - la figure3A est une vue partielle en coupe transversale d'une variante d'exécution du premier mode de réalisation, montrant une fixation du corps de chauffe au réservoir ;
• - la figure 3B est une vue de dessus de la figure 3A ;
• - la figure 4 est une vue semblable à la figure 3A d'une autre variante d'exécution du premier mode de réalisation ;
• - les figures 5A - 5C sont des vues partielles en coupe transversale de diverses variantes d'exécution d'un troisième mode de réalisation de l'invention.

The invention will be better understood and other objects, characteristics and advantages thereof will appear more clearly on reading the explanatory description which follows, made with reference to the schematic drawings. annexed ques given only by way of nonlimiting example illustrating several currently preferred embodiments of the invention and in which:

• - Figure 1 is a cross-sectional view of a first embodiment of the hot water production device according to the invention;
• - Figure 2 is a view similar to Figure 1 of a second embodiment of the present invention;
• - Figure3A is a partial cross-sectional view of an alternative embodiment of the first embodiment, showing a fixing of the heating body to the tank;
• - Figure 3B is a top view of Figure 3A;
• - Figure 4 is a view similar to Figure 3A of another alternative embodiment of the first embodiment;
• - Figures 5A - 5C are partial cross-sectional views of various alternative embodiments of a third embodiment of the invention.

With reference to the appended figures, the device for producing hot water according to the present invention comprises a reservoir with a hollow body 1 and a heating body 7.

The reservoir is a hollow body of any suitable shape, in particular of revolution, entirely molded with its pipes or wall crossings 4, 4 ′ intended for the connection of the pipes. In the presently preferred embodiment, the reservoir is made of an aluminum alloy, in particular foundry, for example silicon-magnesium such as that whose standard conventional chemical designation is represented by the symbol AS10G.

The tank 1 can be of any capacity varying for example between 1 and 300 liters.

Furthermore, the reservoir 1 is molded either in two parts 2, 3 to be assembled later in a leaktight manner, or in a single piece if possible, and it possibly remains unmolded, due to the excellent surface condition plain or smooth thus obtained.

The two parts 2, 3 respectively constitute two equal or unequal tank fractions and each of them is, in the example shown, bordered, at the level of the junction or separation plane, by an annular flange 13 radially projecting towards the outside. In this case, the assembly of parts 2 and 3 is carried out either by bolting or by a quick fixing device on flanges with possible interposition of a seal gasket, or by welding of the two flanges. One can also consider an assembly by crimping or by tight screwing of a fraction or part of tank externally threaded in the other fraction or part internally threaded.

The reservoir 1 is provided with at least two wall crossings 4 ′ and 4 made of material, respectively of cold water inlet 14 ′ and hot water outlet 14, preferably made in its domed bottoms. Each wall passage 4, 4 ′ is intended to receive, removably mounted, a tube 5, 5 ′ preferably made of a synthetic material such as in particular polyvinyl chloride. The pipes 5, 5 'are advantageously fixed to the wall bushings 4, 4' by means of elements 6, 6 'such as bolts, nuts, screws or similar fixing members, preferably made of the same dielectric material.

The heating body 7 is advantageously independent of the tank and attached removably thereon. This arrangement allows, unlike known devices, interchangeability of the heating body, facilitating repair or replacement thereof.

In a first embodiment (FIG. 1), the heating body 7 is constituted by a metal block 8, made of aluminum alloy in the example shown. However, in general, this block can be made of any suitable material, preferably with properties similar to those of the material of the hollow body 1, that is to say having good thermal conductive properties.

A heating element, such as an electrical resistor, is embedded in the block 8 which is detachably fixed against the wall surface, in particular the outer wall of the reservoir, in direct heat-conducting contact with the latter.

Such a fixing of the heating body to the tank is carried out for example by central tightening, in particular by nut on a screw inserted in the body 7.

Figures 3A and 3B show an alternative embodiment of the fixing of the heating body 7, which uses the cold water inlet 14 '. This arrangement allows the use of two strictly identical parts 2 and 3, hence a further improved manufacture of the tank. In addition, the heating body 7 is shaped so that it can be dismantled without dismantling the piping. For this, as shown in Figure 3B, a one-sided recess 21 allows the release of the heating body, after removing the nut 22 by sliding normal to the pipe 5 '.

In an alternative embodiment shown in FIG. 4 of the drawings, the heating body 7 comes to fit in an orifice present in the wall of the tank 1, and obtained in particular during molding. The heating body 7 then forms part of the inner wall of the tank body 1. A stirrup 24 bearing on the tank 1 is tightened against the latter by means of a nut 23 which, by screwing onto a threaded rod 25 integral with the heating body 7, allows a movement of the latter in the opposite direction to the movement of the stirrup 24, thereby fixing the heating body 7 to the wall of the tank at a predetermined location. Advantageously, the orifice made in the wall of the tank is of conical shape flaring towards the inside of the tank, so as to cooperate in leaktight manner with the heating body 7 shaped to form a waterproof complementary part of said orifice.

In another alternative embodiment, the heating body 7 consists of an envelope or a closed enclosure 15 filled with a heat-transfer liquid such as water, at least partially surrounding the tank and in thermally conductive contact with that -this (see Figure 1). This liquid, isolated from sanitary water, is heated by an external heat source and transmits its thermal heat to the tank.

On the other hand, the thermal measurement and regulation instruments such as thermometer, thermostat etc., are mounted externally on the tank and, like the heating elements, do not enter the volume containing the water thereof, measurement, detection and capture taking place indirectly.

In another embodiment shown in FIG. 2, the wall of the reservoir 1 forms at least one inva thermowell protruding inwards and surrounded by water, thus constituting a cavity open towards the exterior 10. The blind cavity 10 is intended to preferably accommodate removably the heating element 7, for example in the form of barrel, which bathes in the air contained in the aforementioned cavity. Other similar cavities such as 12 are used to house the aforementioned measuring and regulating instruments.

The reservoir 1 may optionally include an internal coating, in particular of plastic material such as that known commercially under the name of Rilsan or Teflon, to optionally perfect the protective oxide layer forming the skin of the metal. This coating is applied during the cooling of the molded part when it has reached the temperature suitable for the application of this coating.

Of course, the device for producing hot water may include other modifications, without departing from the scope of the present invention. Thus, one can use, for example, a material having good heat-conducting properties only for the production of the portion of the tank 1 comprising the heating body 7, the remaining portion may be made of composite material for example.

The use of an aluminum alloy, especially foundry, for the production of the reservoir 1 makes it practically unalterable. Indeed, the surface oxidation, favored during molding, of the aluminum alloy forms a skin on the metal protecting it against corrosion.

The perfect internal smooth surface prevents any risk that retains foreign matter and corrosion, especially at assembly joints.

In a third embodiment, the heating body is constituted by a heating element, such as one or more electrical resistances directly molded in the mass of the tank 1.

FIGS. 5B and 5C show the case of molded resistors (26, 27) concentrated in a local location, preferably close to the cold water inlet pipe 14 '. The aforementioned resistors are molded in a locally thicker wall portion and projecting either inwardly (27) or outwardly (26) of the reservoir 1.

In an alternative embodiment shown in FIG. 5A, several electrical resistors 28 are molded into the mass of the reservoir at points spaced from the wall of the latter. Advantageously, the resistors 28 are arranged opposite one another, thereby allowing the water contained in the tank to be heated in stages. When the hot water needs are lower than the capacity of the tank, these resistors allow the implementation of a fraction of the heating power adapted to the needs. These resistors also allow reheating of stages, by fractional heating or selective section of the tank height. We can also adapt to declining electricity prices.

Furthermore, if a molded electrical resistance is used, the rate of heat emission (in W / cm ² ) of the known devices is retained.

In the embodiment shown in FIG. 2, the barrel resistance is shaped to occupy the entire space of the cavity 10. The resistance is fixed by a metal bar fixed on the one hand to the resistance and on the other hand to the pipe 5 '.

Claims (10)

1. - Device for producing hot water of the type comprising a hollow body reservoir comprising pipe connection pipes, and a heating body, characterized in that said hollow body (1) is made at least partially of a material in particular metallic able to be molded, preferably in shell or under pressure with its wall crossings and possibly remains raw in the finished state. 2. - Device according to claim 1, characterized in that the material capable of being molded above is chosen from materials having good heat-conducting properties, and is preferably capable of being surface oxidized during molding to form a protective skin. 3. -A device according to claim 1 or 2, characterized in that the aforementioned material is an aluminum alloy, in particular foundry. 4. - Device according to one of claims 1, 2 or 3 characterized in that the aforementioned hollow-body tank (1) is produced in two parts (2, 3) assembled: - either by bolting or leakproof quick fixing device on flanges with possible interposition of a seal gasket, - either by welding the two flanges, - either by crimping, - Either by tight screwing of an externally threaded part in the other internally threaded part. 5. - Device according to one of the preceding claims, characterized in that in each wall crossing (4, 4 ') is removably mounted a tube (5, 5') made of a dielectric material such as in particular polyvinyl chloride, and fixed to said wall passage (4, 4 ') by elements (6, 6 ') in dielectric material. 6. - Device according to one of claims 2 to 5, characterized in that the above-mentioned heating body (7) consists of a block (8) preferably made of a material of the same nature as that of the hollow body (1 ) mentioned above, in which is embedded the heating element (9) such as electrical resistance, and which is removably attached and fixed in direct heat-conducting contact to the wall of said hollow body (1). 7. - Device according to one of claims 2 to 5, characterized in that the heating element (9) such as for example an electrical resistance is preferably housed removably in a blind cavity (10) of the wall of the tank, protruding inward of it. 8. - Device according to one of claims 2, 3, 4, 5, 7, characterized in that the measuring and thermal regulation instruments (11) are preferably housed removably in a second cavity (12) of the wall of the reservoir projecting towards the interior thereof. 9. - Device according to any one of the preceding claims, characterized in that the aforementioned hollow body tank (1) has an internal coating in particular of plastic material such as that known commercially under the name of Rilsan or Teflon. 10. - Device according to one of claims 2 to 5, characterized in that the aforesaid heating body (7) is constituted by a heating element (20) such as for example an electrical resistance molded in the mass of the tank is either concentrated in a local location, or distributed in several points of the tank wall.

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