EP0323942A1 - Hot water accumulator and process for heating this accumulator - Google Patents

Abstract

-The present invention relates to a hot water accumulator comprising a metal tank (1) arranged inside a heat-insulated envelope (2) and also comprising means of heating (9/14) water contained in the tank and thermostatic means (11) for regulation of the temperature of the distributed water, the control box of which is situated outside the tank, characterised in that it comprises, moreover, a heat exchanger (6) situated inside the tank (1) and submerged in the water contained therein, which has its temperature raised by said means of heating (9/14), which exchanger (6) comprises a cold water inlet pipe (6a), which penetrates the lower part of the tank (1), and a hot water outlet pipe (6d) which passes through the tank in its upper part (7) and which extends parallel to the wall of the tank through the layer of heat insulator (5) to reach the lower part of the latter and the probe (1a) of which for said thermostatic means (11) is arranged in a "glove finger" (10) next to the part (6b) of the cold water inlet pipe situated inside the tank (1). -Finds application in sanitary water services. <IMAGE>

Description

The present invention relates to a hot water tank and a method of heating said tank.

The technical sector of the invention is that of devices for the production of hot water, storage tanks and other similar devices.

The hot water accumulators currently on the market and whatever their capacity have a relatively short lifespan, of the order of ten years regardless of the material from which they are made: copper or stainless steel or interior coatings with which they are fitted: enamel or any other anti-corrosion coating.

Indeed, such accumulators are designed to heat a body of water contained in a tank in which, during the drawing off of hot water, a supply of cold water is established by circulation in the tank, which modifies the pH water and correlatively leads to degradation by premature corrosion and / or scaling whose corollary is a relatively short lifespan: ten years.

Another drawback of the known hot water accumulators is that the hot water draw-off tube, which has the function of capturing the water in the upper part of the tank, is disposed inside of it and is at contact with the body of water located at the bottom of said tank, which is tempered by the arrival of cold water admitted to the accumulator. Thus the hot water drawn from the accumulator is at a lower temperature than that captured at the top because of the heat losses inherent in the crossing of said tube in the body of temperate water.

The present invention aims to remedy these drawbacks.

The objective of the present invention is a hot water production tank made from common materials and therefore a very reasonable cost price but which due to its design can have a useful life of the order three times that of hot water storage tanks currently on the market.

This objective is achieved by the water production tank heater according to the invention, comprising a metal tank arranged inside a heat-insulated envelope and further comprising means for heating the water contained in the tank and thermostatic means for regulating the temperature of the water distributed including the control unit and located outside the tank, characterized in that it further comprises a heat exchanger located inside the tank and immersed in the water contained by it , which is raised in temperature by said heating means, which exchanger comprises a cold water inlet pipe which enters the lower part of the tank and a hot water outlet pipe which passes through the tank in its part upper and which extends parallel to the wall of the tank through the thermal insulation layer to reach the lower part thereof and whose probe of said thermostatic means is arranged in a thermowell attached to the part of the tubing d entry cold water inside the tank.

According to the invention, where the tank is formed of a cylindrical shell and two domed bottoms, the exchanger is a helical coil which extends over the height of the tank between said domed bottoms.

In one embodiment, said heating means for accumulating heat in the body of water contained in the tank are arranged in a sealed housing extending inside the tank from the lower convex bond and in which housing an electrical resistance is arranged.

In another embodiment, said heating means for accumulating heat in the body of water contained in the tank consist of a tubular heater in which circulates a heat transfer fluid produced by a generator, which heater extends inside of the tank and at its lower part.

According to the invention, the tank is made of black sheet metal and further comprises a first filling tube which opens into said lower curved bottom on which tubing is arranged a tap or a valve capable of being blocked after filling the tank. and a second tubing for expanding the water contained in the tank, which opens into said upper convex bottom and extends outside the tank on which the second tubing is arranged a tap or a valve capable of being condemned after the expansion water contained in the tank is produced during the heating of this water until the temperature necessary to heat, by heat exchange, is obtained, the water circulated in said exchanger.

The hot water outlet pipe, which passes through the heat-insulating layer, is arranged in an insulating sheath.

In known manner, the thermal insulation which surrounds the tank inside the external envelope is made of expanded polyurethane and the balloon according to the invention is characterized by the fact that the tank is enveloped by a layer of mineral wool brought into contact from the wall of the tank. Said balloon comprises, in addition, between the layer of mineral wool and the expanded polyurethane, a layer of compact felt to perfect the thermal insulation of the tank and protect the expanded polyurethane taking into account the high temperature of the water contained in the tank and which is of the order of 85 ° C.

To fix the balloon to a wall, the latter comprises on the one hand a first support of a U-shaped profile comprising holes for the passage of fixing means to said wall and on the other hand a second support of a U-shaped profile corresponding to said first support to be connected together by fixing means, which second support is fixed to the tank by at least two metal belts which tightly surround the insulating layer of compact felt which envelops the shell of said tank.

The subject of the invention is also a process for heating said hot water production tank, which process is characterized by the following operations:
- The tap on the expansion pipe is opened.
- The tank is filled until the water flows from the expansion pipe and the filling valve is closed and definitively closed.
- Fill the exchanger until the water flows through the outlet pipe and keep the exchanger full of water.
- The water contained in the tank is heated until its temperature reaches approximately 85 ° C .;
- And the excess water from the expansion following the heating of the water contained in the tank is allowed to flow through the expansion tube, this water is removed and the tap of the valve is closed and definitively closed. expansion pipe.

The result of the invention is a hot water production tank of a new design allowing better thermal efficiency and a longer service life compared to similar devices currently known.

• - la figure 1 est une vue en coupe diamétrale d'un ballon de production d'eau chaude selon l'invention; les accessoires tels que mélangeur thermostatique, clapet de décharge etc. ... ne sont pas représentés;
• - la figure 2 est une vue en coupe partielle du ballon de la figure 1 illustrant la partie inférieure du ballon et dont les moyens de chauffe de l'eau contenue dans la cuve sont constitués par un réchauffeur tubulaire;
• - la figure 3 est une vue en coupe transversale suivant la ligne III III de la figure 1 du ballon selon l'invention et dans laquelle l'échangeur et les moyens de chauffe ne sont pas représentés;
• - la figure 4 est une vue en perspective partielle de la cuve qui compose le ballon de la figure 1 et des moyens de fixation dudit ballon à une paroi murale.

The advantages and characteristics of the invention will emerge on reading the following description of an embodiment of a hot water tank and its heating method, given by way of examples with reference to the drawing annexed on which:

• - Figure 1 is a diametrical sectional view of a hot water tank according to the invention; accessories such as thermostatic mixer, relief valve etc. ... are not shown;
• - Figure 2 is a partial sectional view of the balloon of Figure 1 illustrating the lower part of the balloon and the means for heating the water contained in the tank are constituted by a tubular heater;
• - Figure 3 is a cross-sectional view along line III III of Figure 1 of the tank according to the invention and in which the exchanger and the heating means are not shown;
• - Figure 4 is a partial perspective view of the tank which composes the balloon of Figure 1 and means for fixing said balloon to a wall wall.

Reference is first made to FIG. 1 of the drawing which illustrates an embodiment of a hot water production tank according to the invention.

This consists of a tank 1 made of black sheet metal and comprising a cylindrical shell la and two domed bottoms, for example elliptical 1c / 1d. The two bottoms 1c / 1d are assembled by welding to the ferrule 1.

Said tank 1 is disposed inside a heat-insulated envelope 2, which consists of a cylindrical part 2a at the ends of which two covers 2b / 2c fit together. This envelope is made of thin sheet steel and is covered with a protective coating, for example a paint or an enamel.

The tank 1 and the casing 2 are coaxial and the convex bottoms 1b / 1c of the tank are situated substantially at the level of the interlockings of the covers 2b / 2c.

To avoid partial deterioration of the polyurethane expanded, which will be discussed later in this description, due to the relative high temperature of the water contained in the tank 1 of the order of 85 ° C., the latter is enveloped by a layer of mineral wool 3 , for example glass or rock wool or quartz wool, which layer of mineral wool is itself covered by a layer of compact insulating felt 4.

Then and in a known manner, the vacuum existing between the felt 4 and the casing 2 is filled with expanded polyurethane 5. This insulating complex provides excellent thermal insulation of the balloon, which guarantees, at this level, energy savings not negligible.

Inside the tank 1 is arranged a heat exchanger 6. As illustrated in the drawing, in Figure 1 and in a non-limiting embodiment, said exchanger is made of red copper and takes the form of 'a helical tubular coil which extends over the height of the tank 1 between the two curved bottoms 1b / 1c.

Note that the tank could just as easily receive an exchanger adopting any other form: annular, tube bundle or other, etc. ...

In the case of a tubular exchanger, a section of tube is chosen so that the speed of the water does not exceed 1 to 1.20 m / second.

The cold water inlet pipe 6a passes through the wall of the lower curved bottom 1c and is bent twice inside the tank so that a part 6b of said pipe extends substantially in the center of the tank 1. The turns 6a of the exchanger extend parallel to the wall of the shell 1a at a distance relatively close to the latter to reach its upper part. In the upper curved bottom 1b, the coil is extended by a hot water outlet pipe 6d, which extends parallel to said curved bottom 1d and crosses it at 7 to extend parallel to the tank 1 but spaced from this until reaching the lower part of the envelope 2 where it passes through the cover 2c of the latter. The part of the tubing 6d, which extends from the wall crossing 7 to the cover 2c of the envelope is placed in an insulating sheath made of a plastic material, felt or any other material and is embedded in the expanded polyurethane 5 while possibly being in contact with the layer of compact insulating felt 4 which envelops the tank 1.

According to a preferred embodiment, the tubing 6d is disposed in a plastic sheath, itself covered with a strip winding distributed over the length of the tubing and consisting of a thermal insulator made of vacuum metallized polyurethane on a layer of polyethylene foam.

The tank comprises, at its lower part, a sealed housing, for example cylindrical 8, which opens outside the domed bottom 1c and in which housing is placed an electrical resistance 9 to heat the mass of water contained in the tank and which will be discussed later. This housing is parallel to the longitudinal axis of the tank. This also includes a thermowell 10 which is attached to part 6b of the cold water inlet pipe, which thermowell opens out from the domed bottom 1c and receives the probe 11a from a thermostat. 11 fixed by any known means in a housing 12 located in the lower central part of the casing 2 between the latter and the tank 1.

Said housing 12 is closed by a removable hatch 19, for example screwed to the cover 2c of the envelope 2.

The thermowell 10 is preferably silver brazed longitudinally on the tube part 6b and as close as possible to the arrival of cold water.

This arrangement promotes the cooling of the probe 11a of the thermostat 11, which triggers the heating of the resistor 9.

Figure 2 partially illustrates the lower part of the balloon according to the invention. The identical parts which have just been described with reference to FIG. 1 have been given the same reference signs.

In the embodiment illustrated in FIG. 2, the means for heating the mass of water contained in the tank are constituted by a tubular heater with helical coils 14, the "go" 14a and "return" pipes 14b of which are connected known manner to a hot water generator, for example a boiler (not shown) whose burner is started by the thermostat 11.

Said heater 14 is arranged for example in place of the electrical resistance 9 and its housing 8. A heat transfer fluid, for example water, is circulated in the tubing of the heater 14 in order to heat the mass of water contained in the tank. It comprises a tube 14c extending outside the upper part of the casing 2 and at the end of which is mounted an automatic air vent.

We return to Figure 1 of the drawing.

The tank 1 further comprises, at its lower part, a cold water filling pipe 15 which opens into the convex bottom 1c, which pipe 15 comprises a tap or a stop valve 16 and, at its upper part, a another expansion pipe 17 of the water contained in the tank, which pipe 17 opens into the convex bottom 1b and extends outside the tank 1 and passes through the cover 2b of the envelope 2. This pipe 17 also includes a stopcock or valve 18.

Because all the pipes and other accessories such as the housing 8 or the thermowell 10 are brazed to the curved bottoms 1b or 1c, the tank is perfectly sealed and it is therefore unnecessary to equip it with "head plates" or inspection hatches with which the devices currently on the Market are fitted.

The upper internal part of the tank 1 can optionally be coated with an anti-rust insulating coating to compensate for the harmful effects of the water vapor created by the heating of the mass of water contained in the tank 1.

To heat the balloon according to the invention and during its installation, an operation which is in principle carried out only once, the procedure is as follows:
- Open the valve 18 of the expansion tube 17 to create a vent at the top of the tank.
- The tap or valve 16 of the cold water inlet pipe 15, located at the bottom of the tank, is opened and the tank 1 is filled until the water drains from the pipe d expansion 17 so as to completely expel the air contained in the tank and the tap or filling valve 16 is closed and definitively condemned.
- The exchanger 6 is filled until the water flows through the hot water outlet pipe 6d and the exchanger is kept full of water.
- The water contained in the tank 1 is heated by switching on the heating means 9 or 14 until the temperature reaches approximately 85 ° C.,
- And the excess water from the expansion following the heating of the water contained in the tank is allowed to flow through the expansion tube 17 and this water is discharged either in a container or in the sewer and closes and definitively locks the tap 18.

To lock the taps or valves 16/18, disassemble their spider or their handwheel and pour a wax, for example sealing wax around the control axis of the tap or valve to make the connection of the rod of the gland and the body of the tap or valve.

It will be noted that according to the invention it is the water which has been introduced into the tank during the first heating up which remains permanently in the tank without ever having to add or extract the smallest amount of water therein.

It is in view of this design that it was possible to make the tank out of black sheet metal because of the practically non-existent risks of corrosion and scaling. To this end, it is not useful to equip the balloon according to the invention with anodic protection.

Of course, the essential condition for the proper functioning of the balloon according to the invention is that it is provided with effective means for regulating the temperature of the water without it exceeding 85 ° C. The tank is thus equipped with all safety devices such as a relief valve and a thermostatic mixer, which has the following very important effect:
- avoid accidents caused by hot water burns,
- to save energy,
- to save time by no longer having to search for the temperature of the bearable hot water,
- to save water.

Finally, reference is made to FIGS. 3 and 4 of the drawing which illustrate new means of fixing the balloon according to the invention to a wall wall. These means have the advantage of avoiding thermal bridges and ensuring good thermal insulation of the tank.

They consist of a first support of a U-shaped profile 19 comprising a part 19a intended to be applied against the wall, which part is pierced with holes 19b for the passage of fixing screws and two wings 19c perpendicular to the part 19a and comprising substantially in their central part a hole 19c₁ and a second support 20.

Said support 20 is complementary to the first support 19 and like the latter, it comprises a part 20a intended to be applied to the layer of compact felt 4 and two wings 20b which comprise, in their central part, a hole 20b₁.

Said supports 19/20 can be identical and in this case, after having fixed the support 19 to the wall, the ball is placed by resting the wings 20b of the assumption 20 on the upper face of the wings 19c of the support 19. Then we assemble the two supports by means of bolts passed through the holes 19c₁ / 20b₁ reserved in the wings 19c / 20b.

To fix the support 20 to the tank covered with two insulating layers: mineral wool 3 and counting felt 4; said support 20 is applied to the felt layer and the tank and the part 20a of the support 20 are surrounded by circular metallic belts 21, for example two in number. In known manner, said belts 21 are open and have at their free end a return 21a / 21b extending substantially orthogonally to the belt, which returns are drilled in their central part to pass a tightening bolt which ensures the holding of the belt. on the partially insulated tank.

The envelope has slots for the passage of the wings 20b of the support 20 and the expanded polyurethane is injected into the annular space existing between the insulating coating of compact felt and the envelope 2.

Of course, without departing from the scope of the invention, the parts which have just been described by way of example may be replaced by a person skilled in the art by equivalent parts fulfilling the same function.

Claims (10)

1. Hot water production tank comprising a metal tank (1) disposed inside a thermally insulated envelope (2) and further comprising means (9/14) for heating the water contained in the tank and thermostatic means (11) for regulating the temperature of the water supplied, the control unit of which is located outside the tank, characterized in that it further comprises a heat exchanger ( 6) located inside the tank (1) and immersed in the water contained therein, which is raised in temperature by said heating means (9/14), which exchanger (6) has a tubing d cold water inlet (6a) which enters the lower part of the tank (1) and a hot water outlet pipe (6d) which passes through the tank at its upper part (7) and which extends parallel to the wall of the tank through the thermal insulation layer (5) to reach the lower part thereof, and the probe (11a) of said thermostatic means ( 11) is arranged in a thermowell (10) attached to the part (6b) of the cold water inlet pipe located inside the tank (1). 2. Balloon according to claim 1, the tank (1) of which is formed by a cylindrical shell (1a) and two curved bottoms (1b / 1c), characterized in that said exchanger (6) is a helical coil which s 'extends over the height of the tank (1) between said curved bottoms (1b / 1c). 3. Balloon according to any one of claims 1 or 2, characterized in that said heating means, for accumulating heat in the body of water contained in the tank (1) are arranged in a sealed housing (8) s 'extending inside the tank from the lower curved bottom (1c) and in which housing is arranged an electrical resistance (9). 4. Balloon according to any one of claims 1 or 2, characterized in that said heating means for accumulating heat in the body of water contained in the tank (1) consist of a tubular heater (14) in which circulates a heat transfer fluid produced by a generator, which heater (14) extends inside the tank (1) and at its lower part. 5. Balloon according to any one of claims 1 to 4, characterized in that the tank (1) is made of black sheet metal and further comprises a first filling tube (15) which opens into said lower curved bottom (1c) on which tubing (15) is arranged a tap or a valve (16) capable of being blocked after filling the tank (1) and a second expansion tubing (17) of the water contained in the tank (1), which opens into said upper convex bottom (1b) and extends outside the tank, on which second tubing (17) is arranged a tap or a valve (18) capable to be condemned after the expansion of the water contained in the tank has occurred during the heating of this water, until the temperature necessary to heat, by heat exchange, the water put in circulation in said exchanger (6). 6. Tank according to claim 1, characterized in that the tubing (6d) for the outlet of hot water which passes through the layer of insulation (5) is disposed in an insulating sheath. 7. A balloon according to any one of claims 1 to 6, the insulation of which surrounds the tank inside the outer casing consists of expanded polyurethane (5), characterized in that said tank (1) is wrapped by a layer of mineral wool (3) brought into contact with the wall of the tank (1). 8. Balloon according to claim 7, characterized in that it further comprises, between the layer of mineral wool (3) and the expanded polyurethane (5), a layer of compact felt (4) to perfect the thermal insulation. of the tank and protect the expanded polyurethane taking into account the high temperature of the water contained in the tank and which is of the order of 85 ° C. 9. Balloon according to any one of claims 1 to 8, comprising means for fixing to a wall, characterized in that these means consist firstly of a first support (19) of a profile in the form of U comprising holes (19b) for the passage of fastening means to said wall and on the other hand a second support (20) of a U-shaped profile and corresponding to said first support (19) to be connected together by fixing means, which second support (29) is fixed to the tank (1) by at least two metal belts (21) which closely surround the insulating layer of compact felt (4) which envelops the shell of said tank. 10. A method of heating the hot water production tank according to any one of claims 1 to 9, characterized by the following operations:
- The tap (18) of the expansion pipe (17) is opened.
- The tank is filled (1) until the water flows from the expansion pipe (17) and the filling valve (16) is closed and definitively closed.
- Fill the exchanger (6) until the water flows through the outlet pipe (6d) and keep the exchanger full of water.
- The water contained in the tank (1) is heated, until its temperature reaches approximately 85 ° C;
- And the excess water from the expansion resulting from the heating of the water contained in the tank (1) is allowed to flow through the expansion tube (17), this water is discharged and closed and condemned definitively the valve of the expansion pipe (18).

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