FR2469667A1 - Water heater energy source conversion system - uses interspace(s) between condenser tube and sheath tube filled with thermal conductive material - Google Patents

Abstract

The water heater, converted from existing water heaters or in newly designed and manufactured water heaters, has a condenser tube of a refrigeration unit in thermal conductive contact but not intimate contact with the water to be heated. A sheath tube is provided in conjunction with and outwardly disposed to the condenser tube. The inter-space or interspaces between the condenser tube and the sheath tube is filled with thermal conductive material. The interspace is open or fragilely rupturable to the outside of the water heater.

Description

 WATER HEATER.

 The domestic water heaters which are manufactured and used at present consist essentially of two types, that is to say the type with electrical resistance (I2R) and the type with gas flame. These two types are absolutely not effective in relation to the current requirements concerning energy reserves and savings. Although the invention also relates to the new manufacture of domestic water heaters, one of the difficult problems which it solves is the conversion of the millions of water heaters of the two types which are currently in service.

The object of the invention is to provide a manufacturing design and a conversion design making it possible to obtain a higher coefficient of performance than the existing conventional apparatus and methods. During experiments, the application of the present invention made it possible to reach a coefficient of performance more than three times greater than that of the electric heating system (by resistance).

In the conventional water heater of either type, cold water enters the upper part and is channeled through the inlet pipe to a discharge point located near the bottom of the tank . The main heat source is located on or near the bottom of the tank and the cold water introduced is heated in this area. The heated water rises, by convection, and it is discharged to the upper part of the tank.

 In conventional electric water heaters, two resistance heating elements are provided. The main element is inserted through an opening in a screwed or bolted plate near the bottom of the tank. The secondary or auxiliary element is inserted through a similar orifice, placed near the top of the side of the tank. In one embodiment of the present invention, the main element is replaced and the unchanged element is left unchanged. auxiliary secondary element so that it operates with its existing capacity.

In another embodiment of the invention, one or both elements are replaced, and the water is heated outside the tank. This latter embodiment is also suitable, in particular, for the conversion of gas water heaters, since the only inlet to the tank near the bottom corresponds to the drainage pipe, the cross section of which is only about 18 mm. However, this latter embodiment is also applicable to the conversion of gas and electric water heaters, the inlet being made through the orifice provided in, or near the top of the tank for the dispensing valve. , in particular of the "T & P" type, by using a very long extender7 terminating near the bottom of the tank, for the cold water intake.

 In a conventional gas water heater, the main source of heat is a gas burner mounted below the bottom of the tank, while the secondary source of heat is formed by the central duct in which the hot combustion gases rise. to transfer their residual heat to the surrounding water and exit to the upper part of the tank for between discharges into the chimney. Since, in the implementation of the present invention, it is not necessary to use hot combustion gases, it is possible to replace the two heat sources and eliminate the external connection with the chimney.

In both types of conventional water heaters, there is provided a packing or coating material which is very fragile, such as glass. Therefore, when converting the heat source, it is important to use existing openings and to avoid cutting new openings in the tank. However, this limitation does not concern the application of the invention to newly manufactured water heaters.

 The present invention relates to devices for replacing existing heat sources in existing and newly manufactured water heaters and it also relates to the method of installing these devices in water heaters currently in service. These devices essentially include new arrangements of the condenser tubes of a standard refrigeration or air conditioning unit and the processes relate to the installation of the devices in place of the conventional heat sources found in water heaters. Since manufacturers of water heaters devote large capital costs to the design, tooling and production methods of water heaters which are manufactured and sold at present, the present invention offers advantages for water heaters to be manufactured in the future, in line with new designs and also those already in use, and it also provides advantages for newly designed and manufactured water heaters in which more suitable ports can be arranged to allow the introduction and installation of the condenser tube heating element.

 In the current use of refrigeration and air conditioning units, the heat which is generated by the compressor and the tubular condenser is lost and its dissipation sometimes requires inconvenient or difficult installations.

The present invention provides a practical, economical and efficient means for ensuring the dissipation of this heat.

In all the embodiments of the invention, the tubular condenser containing the hot refrigerant, such as
Freon is in thermal conductive contact, but not intimate, with the water to be heated in the tank. The absence of intimate contact is intentionally maintained so that the integrity of the drinking nature of the water is not altered by a rupture of the tubular condenser and by the exhaust resulting from the refrigerant in the water in the tank. Although it can be considered that at present all the regulations do not specifically impose such security, it should however be considered that more perfect security conditions will be promulgated.

Consequently, in the embodiments of the present invention where the devices are introduced directly into the water located inside the heating tank and where the water is evacuated from the tank to then be heated and reintroduced into this, the tubular condenser is surrounded by a sheath of heat conductive and corrosion resistant material, which is metallurgically compatible with the material of the tubular condenser and which is placed outside of it, being spaced intermittently or evenly or intermittently with respect to the outer periphery of the tubular condenser. The intermediate space (s) are filled with a thermally conductive material, such as copper, aluminum, carbon, graphite, silicone, for example of the "FDA" type, or a similar material, in the form of a powder, of fine particles, of a gel or in the fluid state, or alternatively with thermally conductive liquids such as water, mineral oil and similar substances, or with combinations of the two types of material.

However, in experiments it has been found that the use of water to fill the infill (s) is effective, safe and convenient. The outer ends of the intermediate space are open, or are made fragile to rupture, towards the outside of the tank so as to allow an escape of the refrigerant in the event of rupture of the tubular condenser and thus signal the appearance of a rupture in the sheath. The same type of sheath tube is used in the present invention, in the embodiment where the water is channeled outside the tank to then be heated and reintroduced therein.

 In the tubular condenser sheath according to the invention, it is desirable to maintain the relatively uniform spacing interval between the exterior of the tubular condenser and the interior of the sheath in order to obtain a reasonable uniformity of distribution of the thermally conductive material introduced. in said interval, while providing a means of preserving a thermally conductive space to maintain optimal conditions of heat transmission.

For this purpose, there are provided, in accordance with the present invention, a number of different designs of condenser tube and sheath. In one embodiment, spacers are provided on the tubular condenser, which are oriented radially outward so as to come into sliding contact with the inner surface of the sheath.

In another embodiment, the reverse structure is adopted, that is to say that the fins are fixed to the inner surface of the sheath and extend radially inward so as to come into sliding contact with the outer surface of the tubular condenser. In another variant, the use of modern extrusion techniques makes it possible to manufacture the entire sheath tube with spacing fins which are in fixed contact with the inside of the sheath and the outside of the tubular condenser. In another embodiment, the sheath is intermittently crimped on both sides so as to establish contact with the tubular condenser. In yet another embodiment, longitudinal or helical projections are provided on the tubular condenser and / or on the sheath. It should however be noted that other forms and combinations can be adopted, the main thing being to have a good transmission of heat between the hot condensed refrigerant and the sheath and a preservation of the potable nature of the water.

With the standard refrigeration unit which is used in the present invention, the refrigerant is discharged from the compressor to the condenser, it is passed through a dryer and a capillary expander or other expansion device, the steam is passed thus created in the cooling coils or the evaporator, then the fluid is returned to the compressor. All these operations are well known and with the exception of the condenser, we will not describe them in detail below.

 In the application of the invention to electric water heaters or the introduction of the tubular condenser and the sheath is effected by means of the orifice in which the lower heating element has been mounted, a form of cylindrical propeller or truncated conical propeller. Although the shape of a truncated conical propeller allows the approximation of the turns of the truncated end which have also been introduced ini, experience has shown that it was not possible to place inside the tank a length of tube and condenser sheath larger than with the cylindrical helix shape and in addition the forming was slightly more difficult.

As will be explained below, there are critical parameters which are constituted by the diameter of the propeller, the distance between the turns and the inside diameter of the water tank. It is appropriate to introduce into the tank a length of tube and condenser sheath corresponding approximately to 3.3 m and this has been achieved in the application of the present invention. It is obvious that, after the ex hopper of the initially introduced propeller has come into contact with the opposite side of the tank, it is possible to produce a certain compression or reduction of the space existing between the turns, which allows thus introducing a length of the tubular condenser and sheath, but such compression of the propeller is limited by the risk of deformation, and even rupture, of the tubular condenser and / or of the sheath.

As regards the manufacture of the cylindrical helix shape, it is desirable to limit the conditions of introduction of the structure so that the dimension existing between the adjacent turns is not less than half the outside diameter of the 'propeller.

 In older electric water heaters, the inlet opening of the resistance heating element is formed in a bolted plate, while more recent models have a threaded flange which is fixed inside the tank.

In either case, the opening available for the introduction of the tubular condenser and the helically wound sheath has a diameter of the order of 32 mm. The introduction is carried out by inserting the front end of the tubular condenser and of the sheath in the orifice of the tank and by turning the propeller approximately around its longitudinal axis, while maintaining it in a position such that the part passing through the vessel orifice makes the largest possible angle with the longitudinal axis of the orifice, according to what is allowed by the dimensions of the cooperating elements. In this regard, we realize that the most advantageous condition corresponds to the case where the major axis of a cross section of the tubular condenser and of the sheath is approximately perpendicular to the longitudinal axis of the propeller. the maximum length and to have the minimum spacing between the turns, it is necessary that the outer end of the major axis of the cross section of the tubular condenser and of the sheath is inclined towards the front end of the propeller.

Obviously, in the embodiment of the invention where the water is removed from the tank to then be heated and reintroduced therein, these critical dimensional considerations do not exist.

For the standard refrigeration unit used in the present invention, the refrigerant is discharged from the compressor to the condenser in a temperature range approximately between 60 and 820C, which corresponds to a suitable heat source to heat the water up to at the conventional temperature of 60 to 700C. It is evident that the refrigerant is cooled to a lower temperature when it passes through the condenser, which corresponds to one of the functions performed by this condenser in the refrigeration process. Since it is necessary, in the present invention, that the refrigerant is channeled through the tubular condenser sheathed both to and from the tank, there must be continuous condenser inlet and outlet tubes and a continuous duct, this duct having to be open towards the outside of the tank , or else be provided in this area with a fragile part capable of breaking easily. I1 is not possible to make a return bend of 180 at the front end or inlet of the propeller without excessively crushing the thin copper pipe which is used in the tubular condenser and the sheath. Consequently, the invention provides for each of these parts return caps which are fixed by brazing or welding in position before insertion. It can be seen that the condenser outlet tube gradually cools from the return point to the tank outlet and that the condenser inlet tube gradually heats up from the return point to the inlet into the tank. Although this is not necessary, it is possible to provide insulation between the tubes when they are housed in a single sheath.

 It is obvious that, in the embodiment where they are provided with separate sheaths, it is not necessary for them to be fixed in contact with one another. The heat transmission between the sheath and the water can be increased by fixing on the latter thin thermally conductive radial fins, the connection of which with the sheath is ensured, for example, by brazing. Although such fins may cause certain difficulties and may become deformed, during the introduction process this deformation is not significant since the fins continue to act as a heat transmitting surface, even when deformed state.However, it is important that such fins are provided on the sheath only in positions where they are aligned approximately parallel with the flow of water being heated. Otherwise, it has been found that they can hinder this flow by convection, which is undesirable.

 For the application of the present invention to water heaters of new design and manufacture, it is preferable to mount the compressor and the evaporator of the refrigeration unit at the upper part of the tank. This arrangement conserves the space available on the ground and uses, for the refrigeration system, a volume which is ordinarily not occupied during the conventional installation of a water heater.

Furthermore, more importantly, it has been found that the slight vibration which is produced in the tank by the compressor greatly improves the convective flow and the resulting heating of the water. Also, the heat supplied to the compressor by the hot tank-prevents the accumulation of coolant in the compressor and, therefore, the fouling that could result. By adopting such an arrangement for newly designed water heaters, the position and the space limitation of an existing orifice for the insertion of a sheathed tubular condenser into the tank are not taken into account since it an orifice is provided which has suitable dimensions and positioning. In such an application mode of the present invention, the associated condenser inlet and outlet tubes penetrate through an orifice provided at the top of the water heater, at the same time time as the sheath, and they extend approximately to the bottom of the tank where they end in a helical turn. In another embodiment of the invention, the associated condenser inlet and outlet tubes exit from the bottom of the water heater, they are provided with appropriate insulation, and they enter through an orifice made in the side from the tank near the bottom, at the same time as the sheath, to end with a helical turn or a multiplicity of elbows.

In water heaters of new design and manufacture, the present invention can be applied very effectively by providing a vertical convection chimney which is placed in the tank and which has a diameter of approximately 100 mm. This chimney or duct can be fixed to the upper part of the tank, or on the bolted plate through which the sheathed tubular conduit passes, and its upper part is provided with a hole of 300 mm, while its lower end is placed near the bottom of the tank. Conversely, the conduit can be fixed to the bottom of the tank, being provided with a hole in its lower part, while its upper end is placed near and below the top of the tank.

The tubular sheath condenser is inserted into this duct and it can be either of the type comprising a helical coil placed near its base end and provided with a straight downward-facing return part, or of the type comprising four vertical sections or more, placed inside the duct. The conduit consists of a plastic pipe or another non-corrosive material, since its thermal conductivity is not important, and it has a diameter large enough to allow a complete return elbow of the sheathed tubular condenser without crushing, which corresponds to approximately 75 mm. In this embodiment of the invention, the convection process begins in cold water located near the bottom of the tank and which is heated by the tubular condenser sheathed inside. and near the base of the pipe, the water rising much faster than it would in the largest volume of the tank, to exit through the top of the pipe and flow down, as it cools or mixes with the colder water in the much larger volume which corresponds to the part of the tank placed outside the duct. In addition, this design allows a concentration of the flow of very hot water at the upper part of the tank, that is to say at the point of taking the hot water.

One can also conveniently apply a variant of the embodiment which has just been described to the conversion of existing gas water heaters. According to this principle, the external flue pipe is removed, which constitutes an extension of the concentric longitudinal internal pipe, since it is no longer necessary. The lower end of the internal pipe is closed off so that it becomes watertight and the gas burner is placed below the bottom of the tank. The sheathed tubular condenser, corresponding to one of the types described above and intended to be placed inside the convection duct, is inserted downwards into the internal duct, then this duct is filled with a thermally conductive material in the form of powder or particles, or else of a liquid such as water, and the upper part of the internal duct is left open, or else its operation is carried out using a fragile material capable of breaking easily. We see that with this conversion principle, the sheath surrounding the tubular condenser could be eliminated and that we can use an ordinary tubular condenser, since the internal duct plays itself the roll of a sheath. However, this deletion n is not recommended for safety, and it is still preferable to use a sheathed tube, since many internal smoke pipes may have suffered disturbing corrosion by combustion gases, and these pipes are therefore likely to leaks.

 The invention relates to a heat source for water heaters, which comprises a sheathed tubular heating coil which is inserted into the water tank of an existing water heater via a suitable orifice, or else in the case of a new design water heater, through a specially arranged orifice. The inlet part of the indoor coil is connected to the compressor side of a conventional refrigeration or air conditioning unit, while the outlet part is connected to the side of the unit corresponding to the cooling coil or The external end (s) of the continuous sheath are open towards the outside of the water tank, or are provided with a fragile zone capable of breaking easily, and the water in the tank is in intimate contact with the sheath. The intermediate space existing between the tubular condenser and the sheath is filled with a thermally conductive material having a relatively large conduction coefficient and fins or corrugations establish a connection between the external surface of the tubular condenser and the internal surface of the sheath, in order to maintain the interval and increase the thermal civility conduc. The sheath and the connection to the outside of the gap between this sheath and the tubular condenser protect the integrity of the potable nature of the water.

When converting existing electric water heaters, most of the sheathed tubular condenser for inlet and outlet which is inserted into the tank is arranged in the form of a cylindrical helix or truncated conical helix and is rotated around of its longitudinal axis, thus being introduced by a screwing movement into the tank via the mounting orifice of the lower heating element constituted by an electrical resistance.

A special seal is provided to surround the sheathed tubular condenser and seal the orifice.

In the application of the invention to water heaters of new design and manufacture, the sheathed tubular condenser for entry and return is introduced via openings provided in an appropriate manner.

 In another embodiment of the invention, applicable to both old and new water heaters, the water is discharged through an orifice, it is heated by contact with a tubular coil with a similar condenser sheath and it is returned to tank.

Other advantages and characteristics of the invention will be highlighted, in the following description, given by way of non-limiting example, with reference to the accompanying drawings in which:
Fig. 1 is a vertical sectional view of an existing electric water heater, which is provided with a heat source converted in accordance with the present invention;
Fig. 2 is a vertical sectional view showing an embodiment of the invention usable as a heat source in newly manufactured water heaters;
Fig. 3 is a partial side view and a partial vertical sectional view of another embodiment of the invention usable as a heat source in newly manufactured water heaters;
Fig. 4 is a sectional view of the sheathed tubular condenser of FIG. 3, made along plane 4-4 of FIG. 3;
Fig. 5 is a vertical sectional view of another embodiment of the invention, usable as a heat source in newly manufactured water heaters;
Fig. 6 is a vertical sectional view of another embodiment of the invention, usable as a heat source in newly manufactured water heaters;
Fig. 7 is a vertical section view of an embodiment of the invention usable as a heat source during the conversion of an existing gas water heater;
Fig. 8 is a vertical sectional view of another embodiment of the invention, usable as a heat source during the conversion of an existing electric water heater;
Fig. 9 is a sectional view showing the cylindrical helix of a condenser sheathed coil, which is partially inserted into the tank of an existing electric water heater which is converted in accordance with the present invention;
Fig. 10 is a sectional view, on an enlarged scale, of the connector surrounding the tubular sheath condenser and which closes the orifice during the conversion of an existing electric water heater, in accordance with the present invention;
Fig. 11 is a sectional view of a form of sheathed tubular condenser according to the invention;
Fig. 12 is a sectional view of another form of a sheathed tubular condenser according to the present invention;
Fig. 13 is a view in longitudinal section of another form of a sheathed tubular condenser according to the invention;
Fig. 14 is a side view and in partial longitudinal section of the return caps of the tubular conduit and of the sheath at the insertion end of the helical coil introduced into the tank, in accordance with the present invention;
Fig. 15 is a sectional view of the return caps of the tubular condenser and of the sheath shown in FIG. 14, this section being made along the plane 15-15 of FIG. 14;
Fig. 16 is a cross-sectional view of the sheathed tubular condenser and the water conduit which are used in the external heat source shown in FIG. 8, the section being made along the plane 16-16 of FIG. 8;
Fig. 17 is a view in longitudinal section of the end of the sheathed tubular condenser and of the water conduit of the
Fig. 16, the cut being made according to plan 17-17 of the
Fig. 16.

 We will describe with reference to FIG. 1 the first embodiment of the invention used for the conversion of electric resistance heaters (I2R).

This water heater has an inner tank 20, conventionally made of steel and provided with an inner lining made of corrosion-resistant material, such as glass, an outer casing 21, an intermediate layer of insulating material, an inlet. cold water 23 entering the upper part of the tank and extending downward to terminate near the bottom of the tank, and a hot water intake 24 starting from the top of the tank. This arrangement of the components is found in practically all water heaters, whether existing, newly manufactured, electric resistance or gas heating, and it can be seen that each of FIGS. 1 to 8 comprises said components.

 The existing upper or auxiliary heating element 25, constituted by an electrical resistance, can remain in the water heater. A conventional refrigeration unit 26, of a well known type and comprising a compressor 27, an evaporator 28 and a fan 29, ensures the transfer of the hot refrigerant from the compressor 27, via the tube 30 and the inlet tube 31, to make it penetrate the condenser sheathed coil 32 which is in the form of a propeller introduced by a screwing movement into the tank through the orifice outside which the lower electric heating element has been removed, the orifice being closed by the fitting shown in FIG. 10.The hot refrigerant passes through the condenser inlet tube 31, located inside the duct, until it reaches the return cap of tubular condenser and duct, designated by 33 and shown in detail in Figs. 14 and 15, the refrigerant then flowing in the condenser outlet tube 34 which remains sheathed until after the outlet of the tank via said connector. After the condenser outlet tube 34, the refrigerant is channeled through a tube 35 to the evaporator 28, then it is returned to the compressor 27 through the tube 36. The inlet tube 31 and the outlet tube 34 are connected to the tubes 30 and 35 outside the tank of the water heater, and beyond the outer end of the sheath, by fittings, of standard threaded type and well known.

 The water to be heated initially enters the tank via the inlet 23, it comes into contact with the hot sheathed condenser coil 32 and / or with water already heated by it, so that it is heated and rises by convection to outlet 24. When there is no consumption of hot water and, consequently, when there is no introduction of cold water, the desired temperature for water is maintained by periodic actuation of the compressor 27, the control of which is effected by a conventional thermostat connected to the drive device of the compressor 27 so as to operate it each time the water temperature reaches the lower limit of the range of selected temperatures.

Considering FIG. 9, it can be seen that the electric heating element has been removed from the existing lower orifice 37, which is provided with an existing internal thread. Before the introduction of the helical coil which was born from the condenser 32 into the tank via the orifice 37, a bevelled ring 38, formed of a metal compatible with the sheath material, is fixed by continuous brazing. the outside of the sheath around the inner opening of the ring 38 in a predetermined position which is situated approximately in front of the outer end of the sheath, after having placed a joint 39 and a male connector 40 around the sheath and in front of the beveled ring 38, these elements being placed in the order indicated for their use to complete the obturation after insertion of the tubular condenser coil 32. The outer circumference of the beveled ring 38 has a circular shape and the front bevel corresponds to the internal bevel provided on the external end of the male connector 40. However, the internal opening of the beveled ring 38 has a configuration corresponding to the external surface of the sheath. Also, before the introduction of the helical condenser coil 32 into the tank, the gaps between the sheath and the tubular condenser 31, 34 are filled with a thermally conductive material and the said intervals are sealed at the outer end of the sheath, using a putty or a membrane 41 of a fragile nature and liable to break easily. Water has been found to be a good heat-conducting material and convenient to be used for filling said spacings.

When the components are in place, as indicated above, the helical coil sheathed with condenser 32 is introduced by passing the front end, over which the return cap 33 has been put in place, through the orifice 37, and by rotating the helical coil 32 approximately around its longitudinal axis in order to make it penetrate by a screwing movement into the tank. By operating in this way, and in particular by exerting a direct thrust after reaching the straight section of the tubular condenser, it is possible to produce a certain longitudinal compression of the propeller without disturbing effect. A male connector 40 is then screwed into the orifice 37, the seal 39 is compressed against the tank and the closure cap 42 is slid over the assembly to screw it onto the external thread of the male connector 40, in order to apply the bevelled ring 38 in tight contact with the internal bevel of fitting 40.

One then ensures the coupling of the condenser inlet tube 31 with the tube 30 leaving the compressor 27, then the condenser outlet tube 34 is connected with the tube 35 leading to the evaporator 28; after the system has been filled with refrigerant, it is ready for operation.

 Fig. 10 shows the tank 20 in which the tubing 37 internally threaded and all the closure elements, the ring 38, the seal 39, the coupling fitting 40, the sealant 41 and the cap 42 are in square. Some of the existing electric resistance water heaters have a bolted outer plate in place of threaded tubing. It is obvious that an adaptation of the shutter assembly according to the invention can be made to such a structure, simply by replacing the coupling fitting 40 of FIG. 10 by a plate provided with corresponding bolt passage holes and by an externally threaded male tube.

 Fig. 11 shows in cross section an embodiment of the sheathed tubular condenser according to the invention, which comprises separate sheaths 43 coming into intimate contact with the water to be heated, fins 44 ~ being fixed on the inner surface of the sheath 43 and on the outer surface of the tubes 31 and 34 of the condenser to create gaps 45 which are filled with a thermally conductive material. Alternatively, the fins 44 can be fixed on the sheath and come into sliding contact with the tubes 31 and 34 of the condenser, or vice versa, in order to facilitate the extrusion. The fins 44 play a double role, namely to maintain relatively uniform spacing intervals and to establish efficient paths of heat transmission between the tubes 31 and 34 of the condenser and the sheaths 43.

At the point of contact between the sheaths 43, it is unnecessary to secure them, which in fact facilitates the introduction of the helical condenser coil 32.

Fig. 12 shows, in section, another embodiment of the sheathed tubular condenser according to the invention, this arrangement being preferable to that indicated in FIG. 11 due to the reduction in dimension of the major axis, if condenser tubes of the same diameter are used, which has a critical influence on the operation of introducing the helical coil sheathed into a tank by the existing mounting orifice of the lower heating element. It is obvious that, if the same dimension is adopted for the major axis in each embodiment, that is to say a dimension corresponding to the maximum diameter of the orifice, the embodiment indicated in FIG. 12 has condenser tubes 31, 34 of larger diameter, which increases its heat exchange capacity. Furthermore, in FIG. 12, the separate elements have the same characteristics and fulfill the same functions as those described above with reference to FIG. 11.

Fig. 13 shows in longitudinal section another form of the sheathed tubular condenser according to the invention, which comprises a tube 46, which is corrugated in the form of a helix, and a sheath 47, which is also corrugated in the form of a helix. The tube 46 is inserted into the sheath 47 so that the tops of the corrugations of the tube 46 engage in the hollows of the corrugations of the sheath 47, thereby establishing good continuous contact for heat transmission and creating a continuous helical interval 48 which is filled with a thermally conductive material. Since it would be difficult to advance a thermally conductive material in the form of a powder or particles, it is necessary to use in this embodiment a thermally conductive material of nature liquid and found to be the most convenient, effective and safe material. Although Fig. 13 only shows a section of the condenser tube 46 and the sheath 48, it is obvious that such an arrangement can be provided both at the inlet and at the outlet of the tubular condenser, as indicated in FIG. 11 , for a conversion of a water heater requiring an inlet and an outlet through the same existing orifice. On the other hand, such a structure is not compulsory in water heaters of new design and manufacture, where one can choose suitably the entry point and exit point of the condenser tubes. These installations will be described below. As will be precise, we can use the structure represented on the
Fig. 13 and a half of the structure shown in the
Fig. 11 for the inlet and outlet tubes of the condenser, the return being carried out by means of elbows formed in the continuous sheathed tubular condenser.

 Figs. 14 and 15 show, overall, the return cap 33 provided on the tubular condenser and the sheath and used in installations where the condenser inlet tube 31 and the outlet tube 34 are enclosed in the same sheath and must be introduced, in the form of a helical coil, through the existing orifice. This return cap 33 comprises a sheath cap 49 which is constituted by a tubular section having the same section as the sheath and large enough to be engaged from the outside by sliding on the sheath, over a relatively short nesting distance. , and to be brazed continuously on the sheath in said interlocking zone. The other end of the sheath cap 49 is closed and sealed by crimping; one can also provide in this zone a solder to make it waterproof.

The tubular condenser cap 50 is arranged in the same way and it has the same shape, but with smaller dimensions, than the sheath cap 49. When preparing the end of the sheathed tubular condenser according to the invention for the installation of the sheath cap 49 and the condenser cap 50, where part of the sheath 43 and the fins 44 are released towards the rear so as to allow the inlet tube 21 and the outlet 34 of the condenser. These protruding ends are then applied against each other, in a controlled unidirectional stamping operation so that their common contact area is flattened and the associated straight sections take an oval shape having essentially the same configuration, but slightly smaller dimensions than the tubular condenser cap 50. Then, the condenser cap 50 and the sheath cap 49 are slidably engaged on the ends of the inlet and outlet tubes 31, 34, on the one hand , and on the sheath end 43, on the other hand, and their brazing is carried out in this order. It is thus realized that the condenser tubes are always surrounded by a sheath, sparingly with an intermediate interval and that, therefore, the integrity of the potable nature of the water in the tank is preserved permanently.

 Figs. 2, 3, 5 and 6 all represent embodiments of the invention relating to water heaters of new design and manufacture where the inlet orifice of the sheathed tubular condenser is suitably positioned and sized to allow the installation of condenser return coils and elbows. All these embodiments involve conventional components, namely an inner tank 20, an outer casing 21, an insulating insulating material 22, a cold water inlet 23 and a hot water intake 24. Also, all of these modes embodiments include the refrigeration unit 26 which is mounted at the top of the tank of the heater and which comprises a compressor 27, an evaporator 28 and a fan 29. It has been found that this upper arrangement of the refrigeration unit is advantageous for the reasons explained above and that in addition this arrangement made it possible to obtain a unified commercial product. However, instead of using a rectilinear evaporator 28, as is common in conventional units, provision has been made for folding the evaporator 28 in the middle so that it comes to be placed in the circumferential contour of the water heater. without causing protrusion.

In the embodiment shown in FIG. 2, the condenser sheathed coil 32, which comprises an inlet tube 31, an outlet tube 34, a return cap 33, a sheath 43 and fins 44, is engaged by a screwing movement through the existing orifice at the top of the tank and it is moved down to a position close to the bottom of the tank. The orifice is then closed by fixing a bolting plate 51, brazed or welded to the sheath 43 and arranged to come to be placed on threaded studs integral with the tank and on a seal.

The sheath 43 ends above the bolting plate 51 and the ends of the above-mentioned intermediate intervals are left open, or else are sealed by a fragile seal which is liable to break easily. Since we are dealing, in this case, with a process for manufacturing a new water heater, the cold water inlet can be put in place after the sheathed tubular coil 32 has been engaged inside of the tank, which allows a widening of the diameter of the coil 32 to a value close to the inside diameter of the tank.

In the embodiment shown in FIG. 3, the mounting orifice is placed on the side and near the bottom of the tank, and it involves a bolting plate 51, fixed by soldering or welding on the sheath 43, and a seal, as in the shutter device in Fig. 2.

However, in this embodiment, the tubular condenser 52, which comprises a single continuous sheathed tube, is arranged in the form of several sections comprising deflection elbows, said sections and deflection elbows comprising elements intervening in half of the section of FIG. 11, or identical to what has been indicated in FIG. 13. There are also provided radial fins 53 in the form of sheets which are fixed to the outer surface of the sheath 43 on the rectilinear sections so that the planes of the fins 53 are vertical, corresponding to the conventional fins provided on the tube d evaporator, in order to increase the heating zone and not to alter convection. The condenser inlet tube 31 starts from the compressor 27 and extends downwards outside the tank, being isolated suitably and protected by casing, to penetrate the sheath 43 outside the tank. The condenser outlet tube 34 exits from the sheath 43 outside the tank and extends rearward, still outside the tank, to the evaporator 28. The sheath 43 ends by an external bolting plate 51 and the ends of said intermediate intervals are also provided with a fragile sealing joint.

Fig. 4 shows an arrangement in which there are provided six straight sections of sheathed tube which constitute the condenser 52 and which can be inserted into the tank through an orifice having a diameter of the order of 88 mm.

 Figs. 5 and 6 show embodiments of the invention where the tubular condenser comprises a single tube surrounded by a sheath and extending continuously from the inlet to the outlet, being placed in a cylindrical convection duct 54. This convection duct 54 has a diameter of the order of 88 mm and it is fixed to a bolting plate 51 to which the sheath 43 is connected by welding or soldering. The closure device, comprising the bolting plate 51 which cooperates with a seal and studs integral with the tank is similar to that described in FIGS. 2 and 3, the sheath 43 ending with the external bolting plate 51 and the ends of the above-mentioned intermediate intervals being left open or else being closed by fragile seals. In this arrangement, the convection duct 54 has at its upper part & ure holes or slots which are formed near its fixing zone with the bolting plate 51, namely at a distance of the order of 300 mm, in order to allow an escape of the hot convection currents from the duct 54.

The lower end of the convection duct 54 is open and ends near the bottom of the tank, essentially at the same distance from this bottom as the cold water inlet end 23. As a variant, the convection duct 54 can be fixed to the bottom of the tank, pierced at its lower part and open at its upper end located near the top of the tank. However, it is preferable to adopt the arrangement described first since it makes it possible to produce a unitary assembly facilitating the insertion through the orifice and the obturation thereof. In Fig. 5, the heating unit is arranged in the form of a helical coil 55 constituted by a sheathed tubular condenser, which is placed in the convection duct 54 and which comes to terminate near its upper end. embodiment, a straight section extending upwards from the lower end of the helical turn 55 is provided in the continuous sheathed tubular condenser to exit through the bolting plate 51.

In Fig. 6, the heating unit 56 is composed of rectilinear sections, elbows and return parts so as to form a continuous sheathed tubular condenser which is placed in the convection duct 54. The heating unit 56 is similar to the heating unit 52 of FIG. 3 but it is longer, so that it does not need to have as many sections and return parts as this heating unit 52. Also, the radial fins 53 provided in the heating unit 52 are not not used in the heating unit 56 because they would then be oriented horizontally and interfere with convection.

Fig. 7 shows an embodiment of the invention allowing conversion of a gas water heater. There is provided a heating unit 57 which is quite similar to the heating unit 56 of FIG. 6 and which is inserted downwards into an existing smoke duct 58, after removal of the external smoke duct (not visible) and after dismantling the gas burner (not shown) on the underside of the tank and tight sealing of the the lower orifice of the internal smoke duct 58 using a plate or a pad 59.

The internal conduit 58 is then filled with a thermally conductive material in the form of powder, liquid or particles, and the upper end of the conduit 58 can be left open, or else be provided with a fragile sealing joint, or else seal it securely, depending on the profitability sought for the conversion. Thus, if the internal smoke duct 58 is securely sealed and if it is filled with a thermally conductive material which is compatible with the preservation of the potable nature of the water present in the tank, damage to this internal duct 58, for example by corrosion, does not prematurely remove the economic advantages of the conversion, since a continuous sheathed tubular condenser is used in the heating unit 57 and since the sheath ends outside said solid sealing means of the internal duct. The final phase of this conversion consists of lining the space below the tank and previously occupied by the gas burner with insulating material. In such a structure, as in all the conversion modes according to the invention, the existing thermostat can be connected to the energy source of the compressor.

 In Fig. 8, there is shown an embodiment of the invention which can be applied either to water heaters of new design and manufacture, or to the conversion of existing water heaters of the electric or gas type. The embodiment shown relates to the conversion of an electric water heater and it involves the same conventional components of a refrigeration unit, namely, a compressor 27, an evaporator 28 and a fan 29. It is obvious that the he refrigeration unit can be mounted on the floor, or placed at the top of the tank. I1 is provided a intake tube 60 for extracting cold water from the tank for reheating, and an inlet tube 61 for returning the heated water to the tank. the inlet tube 61 are inserted into the tank through the orifice corresponding to the lower heating element, after a soldering or brazing operation on a beveled ring, similar to the beveled ring 38 in FIG. 10, the closure being completed in the same manner as in FIG. 10.

The tubes 60 and 61 are not sheathed and satisfactory results are obtained by using piping similar to that used for a tubular condenser. The intake tube 60 and the inlet tube 61 are connected to their corresponding parts outside the tank, using tubular fittings with conventional flanges in order to facilitate the insertion of the assembly composed of the tubes. 60 and 61 and the bevelled sealing ring. The cold water extracted from the tank via the intake tube 60 is channeled to a special fitting placed near the evaporator of the heating unit 62, which is in the form of a helical coil; this water is heated by passing in the intervals existing inside the sheath of the tubular coil 62, then it leaves this heating coil 62 near the compressor side of the heating unit 62, it passes through a pump 63 and it is reinjected into the tank via the inlet tube 61. The pump 63 is driven by the same source of electric current as the compressor 27 and the fan 29 and it is also connected to the thermostat so as not to not intervene until the compressor 27 is not in service.

 Figs. 16 and 17 show the arrangement of the components involved in a sheathed tubular condenser heating unit 62, as well as the special connection of the water intake tube 60, this connection being the same as that provided at the other end of the heating unit 62 for the inlet tube 61.

The tubular condenser 34 is surrounded by the sheath 43 and longitudinal fins 44 come into contact with the interior surface of the sheath 43 and the exterior surface of the tubular condenser 34 to form longitudinal intervals 45 which are filled with a thermally conductive material, all these components being identical to those described above with reference to FIG. 11. Around the sheath 43, a tubular water jacket 64 is provided, comprising longitudinal fins 65 which come into contact with the exterior surface of the sheath 43 and the interior surface of the water jacket 64, creating thus intervals 66 in which the water to be heated passes. Outside the water jacket 64, an insulating material 67 is provided, intended to conserve the heat supplied to the water by the hot refrigerant passing through the tubular condenser 34 and, obviously, the inlet tube 61 is insulated in the same way between its outlet from the heating unit 62 and its inlet into the tank. In the special connections provided at the ends of the heating coil 62, the tubular condenser 34 is connected to the evaporator 28, or else to the compressor 27, depending on the end of the heating coil 62 which is taken into consideration. The fins 65 are notched rearwards from the ends of the water jacket 64 over a sufficient distance to create an annular chamber the end of which is closed off by welding or continuous brazing of the annular channel 68 on the water jacket 64 and the sheath 43. The water intake tube 60, or else the inlet tube 61 along the end of the heating coil 62 which is taken into consideration, is fixed by brazing or welding to a suitable orifice placed on the side of said water jacket 64 in the area of said annular channel. The fins 44 are notched backwards from the end of the sheath 43 over a distance sufficient to allow the mounting of the annular channel 68.

After the intermediate intervals 44 have been filled with the selected thermally conductive material, their ends are closed using a sealant or membrane 41, of a fragile nature and capable of breaking easily.

Claims (18)

 1.- Device for the conversion of the heat source in existing electric water heaters comprising a hot water tank from which the lower electric resistance heating element has been removed, characterized in that it comprises a heating coil inserted into the tank through the orifice from which said lower heating element has been removed, this heating coil being helical and comprising a condenser inlet tube communicating externally with the compressor side of a refrigeration unit to receive hot refrigerant from it and sheathed continuously along its part located inside of the tank using a tubular sheath spaced apart from the condenser inlet tube , a condenser outlet tube communicating externally with the evaporator side of the refrigeration unit so as to bring therein relatively cold refrigerant and sheathed continuously along d e its part located inside the tank using a tubular sheath spaced outwardly from said outlet tube, a sheathed return cap fitting over the inner end of said inlet tubes and condenser outlet and on the inner end of each tubular sheath being arranged to preserve the intervals existing between the tubular condenser and the sheath, a thermally conductive material filling the intervals existing between the exterior of the tubular condenser and the interior of the sheath, each of said sheaths ending near the outside of the tank so that said intervals open into the atmosphere or are closed by a fragile seal, and a sealing means being applied externally to the sheaths and agency for closing said orifice around them.  2.- Device according to claim 1, characterized in that several longitudinal fins, formed of the same material as the tubular condenser and the tubular sheaths, come into contact with the outer surface of the tubular condenser and the inner surface of the tubular sheaths. 3.- Device according to claim 1, characterized in that the condenser tubes are surrounded by means of a single tubular sheath which is spaced apart from said tubes. 4.- Device according to claim 1, characterized in that each condenser tube is corrugated helically and in that each tubular sheath is also corrugated helically, said helical corrugations being arranged to establish contact between the outside of the tops of corrugations of the condenser tube and the interior of the hollows of the corrugations of the corresponding tubular sheath, so as to create continuous helical intervals between the condenser tube and the tubular sheath. 5.- Device according to claim 1, characterized in that the compressor of the refrigeration unit is fixed at the top of the hot water tank, this fixing serving for the transmission of vibrations by the compressor to the water tank hot during operation of said compressor. 6.- Device according to claim 1, characterized in that a thermostat for measuring the temperature of the water being heated in the tank is connected to the electric current source of the compressor and is arranged to control the operation of the latter.  7.- Device for converting the heat source into existing gas water heaters comprising a hot water tank from which the gas heating unit and the external smoke duct have been removed, characterized in that '' It includes a gasket fixed on the lower end of said internal smoke duct of the hot water tank, a heating unit engaged in the upper end of said internal duct and extending down to near its lower end, this heating unit being composed of vertical sections and return bends so as to form an actively sheathed tubular condenser, which is provided with an inlet side and an outgoing outlet side outside the upper end of said internal duct, said inlet side communicating externally with the compressor-side of a refrigeration unit so as to receive hot refrigerant from it while said outlet side communicatesexternally with the evaporator side of the refrigeration unit to supply it with relatively cold refrigerant, said continuous sheath consisting of a tube which is spaced externally from the tubular condenser and which terminates near and above the upper end of said internal duct on the inlet side and on the outlet side of the tubular condenser, while the gap between the outside of the tubular condenser and the inside of the tubular sheath opens into the atmosphere or is sealed by a fragile joint, a thermally conductive material filling said gap existing between the exterior of the tubular condenser and the interior of the tubular sheath, and a thermally conductive material filling the space remaining inside said internal conduit. 8.- Device according to claim 7, characterized in that several longitudinal fins, formed of the same material as said tubular condenser and said tubular sheath, come into contact with the outer surface of the condenser and the inner surface of the sheath.  9.- Device according to claim 7, characterized in that the tubular condenser is corrugated in a helix, in that said tubular sheath is corrugated in a helix and in that said helical corrugations are arranged to establish contact between the outside of the vertices of the corrugations of the tubular condenser and the interior of the hollows of the corrugations of the tubular sheath in order to create a continuous helical gap between said condenser and said sheath. 10.- Water heater, characterized in that it comprises a cylindrical tank intended to receive water to be heated, a refrigeration unit mounted on the upper end of the tank, an orifice placed essentially in the center of said end upper part of the tank and arranged to receive a heating unit which passes through it so as to extend downwards near the lower end of the tank, said heating unit having a helical profile at its lower end, being directed downward from said port, and having a condenser inlet tube communicating externally with the compressor side of said refrigeration unit to receive hot refrigerant therefrom and provided with a continuous tubular sheath placed along its part located inside the tank and spaced outwardly from said condenser inlet tube, a condenser outlet tube communicating externally with the evaporator side of said tank e refrigeration unit to supply it with relatively cold refrigerant and provided along its part located inside the tank with a continuous tubular sheath which is externally spaced from said condenser outlet tube, a sheathed return cap coming from 'Apply to the inner end of said condenser inlet and outlet tubes and on the inner end of each tubular sheath being arranged to maintain the intervals between the tubes. and the sheaths, a thermally conductive material filling the gaps existing between the outside of the tubular condenser -and the inside of said sheaths, each sheath ending near the outside of the tank so that said intervals open into the atmosphere. or are sealed by a fragile seal, a sealing means coming into external contact with the sheaths and arranged to close the orifice surrounding them, and a thermostat arranged to measure the temperature of the water being heated in the tank and connected to the electric current source of the compressor to control the operation of the latter.  11. A water heater according to claim 10, characterized in that several longitudinal fins, formed of the same material as the tubular condenser and the tubular sheaths, come into contact with the outer surface of the tubular condenser and the inner surface of the tubular sheaths. . 12. A water heater according to claim 10, characterized in that the condenser tubes are surrounded by means of a single tubular sheath which is spaced outwardly from said tubes.  13. A water heater according to claim 10, characterized in that each condenser tube is corrugated in a helix and in that each tubular sheath is also corrugated in a helix, said helical corrugations being arranged to establish contact between the outside of the vertices of the corrugations of the condenser tube and the interior of the hollows of the corrugations of the corresponding tubular sheath, so as to create continuous helical intervals between the condenser tube and the tubular sheath. 14.- Water heater, characterized in that it comprises a cylindrical tank intended to receive water to be heated, a refrigeration unit mounted on the upper end of said tank, an orifice formed in the side wall of the tank near and above its lower end, so as to receive a heating unit which extends diametrically from said orifice to near the opposite side wall of the tank, said heating unit being composed of sections horizontal and return bends forming part of a tubular condenser sheathed continuously and comprising an inlet side and an outlet side which extend outside said orifice, said inlet side communicating externally with the compressor side of said refrigeration unit so as to receive hot refrigerant from it, while the outlet side communicates with the evaporator side of the refrigeration unit to supply it with refrigerant atively cold, said continuous sheath being composed of a tube which is spaced outwardly from the tubular condenser and which terminates near the exterior of said orifice and on the outlet side, while the gap existing between the exterior of the condenser tubular and the interior of the tubular sheath is sealed by a fragile seal, a thermally conductive material filling said gap existing between the exterior of the tubular condenser and the interior of the tubular sheath, radial fins in the form of sheets coming into contact with the outer surface of the sheath along said horizontal sections placed inside the tank, a shutter means coming into external contact with said sheaths and being arranged to close said orifice around them, and a thermostat arranged to measure the temperature of the water being heated in the tank and connected to the electric current source of the compressor to control the function ement of the latter. 15.- water heater according to claim 14, characterized in that several longitudinal fins, formed of the same material as the tubular condenser and the tubular sheaths, come into contact with the outer surface of the tubular condenser and the inner surface of the tubular sheaths -. 16. A water heater according to claim 10, characterized in that the heating unit is composed of vertical sections and return bends forming a tubular condenser sheathed continuously and extending downward from said means d obturation close to the lower end of the tank and internally spaced from a cylindrical convection duct extending downwards from said closure means near the lower end of the tank and the lower end of which is open to receive streams of water to be heated which are moved by convection, while its upper end is provided with slots or holes near said closure means so as to allow the discharge of the streams d displaced by convection. 17. A water heater according to claim 16, characterized in that the heating unit is constituted by a tubular condenser sheathed in a continuous manner, extending downwards from said obturation means and arranged in the form of 'a helical coil near its lower end housed in said convection duct, to return upwards from said lower end of the helical coil towards and through said closure means.  18.- Water heater, characterized in that it comprises a cylindrical tank intended to receive water to be heated, a refrigeration unit, an orifice formed in the side wall of the tank near and above its lower end, said orifice being arranged to receive a tube serving to draw from the tank water to be heated and an inlet tube serving to reintroduce water to be heated in the tank, a heating unit arranged in the form of a helical coil and comprising a tubular condenser communicating by its inlet end with the compressor side of the refrigeration unit to receive hot refrigerant from it and by its outlet end with the evaporator side of the unit refrigeration to provide it with relatively cold refrigerant, a tubular sheath spaced outwardly from the tubular condenser, a water jacket of tubular shape which is spaced outwardly from the sheath to create an interva in which the water is heated, and an inlet ring and an outlet ring, placed at opposite ends of the water jacket so as to communicate respectively with said water extraction tube and said water tube. water inlet, a thermally conductive material filling the gap between the outside of the tubular condenser and the inside of the tubular sheath, said gap being sealed by a fragile seal at its opposite ends, a pump communicating with said tube inlet for circulating the water extracted from the tank through said extraction tube by passing it through the heating unit and through said inlet tube to return it to the tank, a sealing means entering externally into contact with the extraction tube and with the inlet tube and arranged to close the orifice surrounding them and a thermostat for measuring the temperature of the water in the tank and connected to the electric current source of the compressor and the pump to control their operation.