Heating devices for electric fluid heating systems

Abstract

A heating device (10) for mounting on a container (11) arranged to receive a fluid to be heated, this heating device comprising: - a sheath (2) for mounting on the container such that the sheath extends inside the container from a wall of the container; - a sodium lamp (1) for placing in the sheath, the sheath being configured to transfer heat generated by the sodium lamp when it is lit in the sheath to the fluid received in the container. Figure for the abbreviation: Fig. 1

Description

Title of the invention: Heating devices for electric fluid heating systems

[0001] The present invention relates to methods and systems for the electric heating of fluids, and more particularly to heating devices intended to equip such systems.

[0002] Here, an electric fluid heating system is defined as any system or installation designed to raise the temperature of a fluid using electrical energy. Such systems are commonly used in many domestic or industrial applications to heat a fluid, most often a liquid, such as water, milk, oil, or a chemical solution.

[0003] These systems generally include a container (such as a tank or vessel) intended to receive the fluid to be heated, and an electric heating element inserted into the container to heat the fluid it contains.

[0004] The heating element is most often a steatite heating element placed in a sealed metal sheath, which is inserted into the heating system container. This element comprises a bare metal wire wound or twisted around insulating elements made of steatite or a similar ceramic material. This encapsulation allows the steatite heating element to transfer heat to the fluid without being directly exposed to it. The absence of direct contact with the fluid facilitates maintenance and replacement of the steatite heating element. In the event of a failure, the steatite heating element can, in fact, be replaced without requiring the heating system reservoir to be drained.

[0005] However, a drawback of these steatite heating elements is their relatively low energy efficiency. A steatite heating element must first heat the steatite elements by conduction, which in turn transmit heat by radiation to the walls of the sheath. In other words, the heat generated by the passage of electric current through the metal wire is first transferred by conduction to the steatite elements, and then diffused by radiation to the walls of the sheath. This results in double heating before heating the fluid contained within the heating system, requiring higher energy consumption to maintain or increase the fluid temperature. Furthermore, the thermal inertia of the steatite elements can slow down heat transfer, thus requiring more time and, consequently, more energy to reach a desired temperature.

[0006] One object of the present invention is to remedy the aforementioned drawbacks.

[0007] Another object of the present invention is to provide a heating device offering improved durability, energy efficiency and ease of maintenance.

[0008] Another object of the present invention is to propose electrically powered fluid heating systems that are more economical in electrical energy.

[0009] Another object of the present invention is to improve the energy efficiency of electric water heaters.

[0010] To this end, a heating device is proposed, firstly, intended to be mounted on a container arranged to receive a fluid to be heated, this heating device comprising - a sheath intended to be mounted on the container so that this sheath extends inside the container from a wall of this container; - a sodium lamp intended to be placed in the sheath, this sheath being configured to transmit to the fluid received in the container heat generated by the sodium lamp when it is lit in the sheath.

[0011] Various additional features may be provided, alone or in combination: - the sodium lamp is a high-pressure sodium lamp; - the heating device also includes a perforated metal casing intended to at least partially enclose the sodium lamp in the sheath; - the heating device also includes a means of holding the sodium lamp in a removable manner within the sheath; - the heating device further includes a thermally insulating cap to close the sheath, this cap being at least partially opaque to the light emitted by the sodium lamp.

[0012] Secondly, an electric fluid heating system is proposed comprising - a container intended to hold a fluid to be heated; - the heating device shown above.

[0013] Various additional features may be provided, alone or in combination: - the electric fluid heating system is an electric water heater, an instantaneous water heater, an electric storage boiler, an instantaneous electric boiler, an electric steam boiler, or a household appliance designed to heat a fluid; - the container is a tank, a heat exchanger or a fluid circulation duct.

[0014] Thirdly, a method for electrically heating a fluid received in a container comprising a sheath extending inside this container from a wall of said container is proposed, this method comprising the following steps: - placing a sodium lamp in the sheath; - ignition of the sodium lamp placed in the sheath, this sheath being configured to transmit to the fluid received in the container heat generated by the lit sodium lamp.

[0015] This method may, in addition, include a step of disposing of a perforated metal casing at least partially enveloping the sodium lamp in the sheath.

[0016] Other features and advantages of the invention will become more apparent and concrete upon reading the following description of embodiments, which is made with reference to the accompanying drawings in which:

[0017] Figure [Fig.1] schematically illustrates an electric fluid heating system according to various embodiments;

[0018] Figure [Fig.2] schematically illustrates a heating device intended to equip an electric fluid heating system according to various embodiments;

[0019] Figure [Fig.3] schematically illustrates a heating device intended to equip an electric fluid heating system according to another embodiment,

[0020] Figure [Fig.4] schematically illustrates the steps of a method for electrically heating a fluid.

[0021] With reference to figures 1-3, a heating device 10 is shown, intended to be mounted on a container 11 arranged to receive a fluid to be heated.

[0022] The container 11 is a receptacle, reservoir, tank, basin, enclosure, heat exchanger, fluid circulation conduit (channel, tube, or pipe), or, more generally, a hollow body suitable for receiving a fluid to be heated. This container 11 may be cylindrical or have any other suitable shape, for example, tubular, conical, or spherical. When also configured to store the heated fluid, the container 11 may have any capacity suitable for use with the electric fluid heating system 12.

[0023] The container 11 includes an inlet or inlet opening for the fluid to be heated and an outlet opening for the heated fluid (not shown in the figures). More generally, the container 11 includes a fluid inlet and a fluid outlet. The fluid is admitted into the container 11 where it is to be heated. The heated fluid can circulate in an open circuit or, conversely, in a closed circuit and thus return to the container 11.

[0024] The container 11 is, in one embodiment, at least partially coated with external thermal insulation to retain heat and prevent heat loss. thermal. Alternatively or in combination, the container 11 includes an inner lining resistant to the fluid to be heated or is made of a material resistant to the fluid to be heated, such as an anti-corrosion inner lining or a stainless steel container 11 when the fluid to be heated includes water.

[0025] To heat a fluid received in the container 11, the heating device 10 comprises a sleeve 2 intended to be mounted on the container 11 so that it extends inside the container 11 from a wall thereof and a sodium lamp 1 intended to be placed in this sleeve 2. The sleeve 2 is configured to transmit, to the fluid received in the container 11, heat generated by the sodium lamp 1 when it is lit in the sleeve 2.

[0026] Indeed, when lit, the sodium lamp 1 (or sodium discharge lamp) radiates heat inside the sheath 2, which transmits it by conduction to the fluid contained in the container 11. The lit sodium lamp 1 heats the sheath 2, which is at least partially immersed in the fluid, with which it exchanges heat. This results in a heat transfer from the sodium lamp 1 to the fluid in the container 11 through the sheath 2, into which the sodium lamp 1 is inserted.

[0027] The sodium lamp 1 is advantageously used as a heating element or heat source. The fluid received in the container 11 is heated indirectly by radiation from the sodium lamp 1 onto the sheath 2 in which it is housed. The sodium lamp 1 heats the wall of the sheath 2 by radiation via the air surrounding the sodium lamp 1 within the sheath 2. The lit sodium lamp 1 indirectly heats the fluid through the wall of the sheath 2 in which it is located.

[0028] When switched on, the sodium lamp 1 generates thermal rays capable of rapidly heating the fluid to desired temperatures. Advantageously, sodium lamps 1 have low energy consumption and a long lifespan. According to the inventor's experiments, using the sodium lamp 1 as a heat source results in energy savings of approximately 30% compared to a steatite heating element.

[0029] The sodium lamp 1 is, in one embodiment, a high-pressure sodium lamp 1 (or sodium vapor lamp). This high-pressure sodium lamp 1, commonly used for street lighting, has demonstrated low energy consumption and high durability.

[0030] By way of non-limiting example, sodium lamp 1 is, for instance, the one commercially available under the name "MASTER SON-T PIA Plus™" from "PHILIPS™" or under the name "Lucalox™" from "General Electric™". These high-pressure sodium lamps 1 are available in several wattages (for example, 600 W, 400 W, 250 W, 150 W, 100 W, 70 W and 50 W). The wattage of sodium lamp 1 can The choice of sodium lamp depends on the desired heating temperature and / or the volume of fluid to be heated. Advantageously, these sodium lamps offer consistent flow over time and an economical lifespan of tens of thousands of hours (for example, according to the manufacturer, 36,000 hours for the 400W "MASTER SON-T PIA Plus™", which is equivalent to more than 12 years of use for an average heating of 8 hours per day).

[0031] The sleeve 2 extends inside the container 11 from one of its walls like a glove finger or a glove-like sleeve adapted to house the sodium lamp 1. The sleeve 2 extends inside (or within the internal volume of) the container 11 and thus comes into contact with the fluid to be heated contained in this container 11. The sleeve 2 is at least partially immersed in the fluid to be heated received in the container 11.

[0032] Advantageously, existing sodium lamps 1 are generally tubular or ellipsoidal in shape, suitable for placement in a tubular sheath 2. For example, the aforementioned commercially available high-pressure sodium lamps 1 have a tubular shape that can be placed in the sheath 2 of a prior art water heater in place of a steatite heating element.

[0033] The sheath 2 is sealed against the fluid to be heated so as to protect the sodium lamp 1 from this fluid. This seal ensures that the fluid cannot come into direct contact with the sodium lamp 1, thus protecting the latter from any form of deterioration or failure caused by the fluid received in the container 11. Advantageously, the absence of direct contact with the fluid also facilitates the maintenance and replacement of the sodium lamp 1. The sodium lamp 1 can be placed in or removed from the sheath 2 without requiring even partial draining of the container 11.

[0034] The sheath 2 is made of a thermally conductive material, allowing optimal transmission of the heat generated by the sodium lamp 1 lit inside it. In one embodiment, the sheath 2 is made of a metallic or composite material. For example, the sheath is made of copper, copper alloy, or stainless steel.

[0035] In one embodiment, the sheath 2 is made of externally enameled metal (for example, enameled steel) or includes an anti-corrosion coating, to limit the risk of corrosion in the case of a fluid to be heated comprising water.

[0036] Advantageously, the sodium lamp 1 produces substantially uniform heating or, more generally, non-directional heat radiation. This results in heat transfer to the sleeve 2 without irregularities that could generate hot spots which may initiate corrosion of the sleeve 2. In other words, the sodium lamp 1 ensures a substantially uniform distribution of heat to through the sheath 2, extending its lifespan and optimizing the fluid heating process.

[0037] In order to ensure uniform heat distribution within the container 11 and / or to maximize the contact of the sleeve 2 with the fluid to be heated, the sleeve 2 extends inside the container 11, preferably from a bottom or side wall thereof. The arrangement of the sleeve 2 illustrated in [Fig. 1] is obviously not limiting and is given only as an example.

[0038] To hermetically seal an opening in the wall of the container 11 from which the sleeve 2 extends inside it, the heating device 10 comprises, in one embodiment, a flange 3 to which the sleeve 2 is attached. This flange 3 is a base, a plate, a cover, a support, or, more generally, an intermediate piece that allows the sleeve 2 to be mounted in a hermetic manner (with respect to the fluid to be heated) on the container 11. The sleeve 2 can be attached to the flange 3 by welding, brazing, or any other suitable fastening method. In another embodiment, the sleeve 2 and the flange 3 are manufactured as a single piece (a single unit) for improved structural integrity.

[0039] The flange 3 can be fixed by means of fastening (in particular, screws), possibly with the interposition of a sealing gasket, to the wall of the container 11. Preferably, the flange 3 is provided with thermal protection to prevent heat loss and radiation of heat to the outside of the sleeve 2.

[0040] In another embodiment, instead of being carried by a flange 3, the sleeve 2 is fixed directly in a sealed manner to the wall of the container 11. For example, the sleeve 2 is integrated directly into the structure of the container 11, that is to say, it is made in one piece with the wall of the container 11.

[0041] A retaining means 4 allows the sodium lamp 1 to be placed (or arranged) in the sheath 2 in a removable manner. This retaining means 4 comprises, in one embodiment, a lamp holder or lamp support allowing the sodium lamp 1 to be connected to a power supply and a removable attachment means to the flange 3 or the sheath 2 to retain the sodium lamp 1 in the sheath 2.

[0042] As illustrated in [Fig. 1], the sodium lamp 1 is placed in the sleeve 2 so as to maintain a predefined space between the inner surface of the sleeve 2 and the sodium lamp 1. Preferably, a predefined minimum distance (for example, between 3 mm and 50 mm, preferably between 3 mm and 40 mm, or between 5 mm and 30 mm) separates the sodium lamp 1 (or the glass bulb of the sodium lamp 1) and the inner face of the sleeve 2.

[0043] The attachment of the retaining means 4 to the flange 3 or the sleeve 2 can be effected by any known removable fastening means (for example, a thread or equivalent). Thus, the sodium lamp 1 can be placed inside the sleeve 2. or be removed simply by engaging or disengaging the removable fastening means.

[0044] To limit heat loss and prevent overheating of the surrounding environment, the heating device 10 includes, in one embodiment, a thermally insulating plug for closing the sheath 2. This plug may be separate from, or part of, the retaining means 4. In other words, the retaining means 4 may also serve as a plug for closing the sheath 2. In one embodiment, the plug is at least partially opaque (or impermeable) to the light emitted by the sodium lamp 1. This plug blocks, at least partially, the transmission of light emitted by the sodium lamp 1 outside the sheath 2.

[0045] In an embodiment illustrated by [Fig. 3], the heating device 10 comprises a perforated metal casing 5 that at least partially encloses the sodium lamp 1 in the sheath 2. In other words, the sodium lamp 1 is surrounded, at least partially, by a perforated metal casing 5, that is, provided with holes or openings distributed substantially uniformly on its surface. The surface of the perforated metal casing 5 may, in one embodiment, have a mesh or a grid. In other words, it comprises regularly distributed openings formed by a mesh pattern (perforations in a material) or a grid pattern (a structure made up of intersecting wires to create regular spaces). More generally, the perforated metal casing 5 may be a metal casing with a mesh surface or a casing with a perforated mesh surface.

[0046] In one embodiment, the perforated metal casing 5 is a perforated cylinder or, in other words, a sieve cylinder arranged around the sodium lamp 1. This sieve cylinder extends along the longitudinal axis of the sodium lamp 1.

[0047] In another embodiment, the perforated metal casing 5 comprises at least one winding of metal wire around the sodium lamp 1. The perforated metal casing 5, or at least a portion thereof, is formed by one or more windings of metal wire, in particular crossed windings, around the sodium lamp 1. A winding of metal wire comprises a bare conductive wire wound, or coiled, in a helical or spiral shape along the longitudinal axis of the sodium lamp 1.

[0048] The perforated metal casing 5 is made of a material that can withstand high temperatures, such as stainless steel. The perforated metal casing 5 can be fixed or carried by the retaining means 4 or fixed to the inner wall of the sleeve 2.

[0049] Advantageously, the perforated metal casing 5 arranged around the sodium lamp 1 in the sheath 2 accelerates heat diffusion and, by Consequently, the heat exchange with the fluid is optimized to quickly reach the desired temperature and thus reduce the operating time of the sodium lamp 1. This advantageously results in improved thermal efficiency of the heating device 10 and an increased lifespan for the sodium lamp 1.

[0050] To control the operation of the heating device 10 and optimize its electrical energy consumption, the flange 3 can, in a known manner, carry a thermowell 6 intended to receive safety and control means such as a sensor or a temperature probe for measuring the temperature of the fluid inside the container 11. The temperature probe is connected to a thermostat or a temperature control means (not shown). This temperature control means switches the sodium lamp 1 on or off to reach a setpoint temperature of the fluid received in the container 11.

[0051] In non-limiting embodiments, the heating device 10 shown above is mounted on the container 11 of an electric fluid heating system 12 such as the tank of an electric water heater (of the type electric storage water heater, commonly called a "hot water tank"), the heat exchanger (or heating element) of an instantaneous (or on-demand) water heater, the tank of an electric storage boiler, the heat exchanger (or heating element) of an instantaneous electric boiler, the heating tank (or reservoir) of an electric steam boiler, a heating container (or reservoir) of a household appliance designed to heat a fluid such as an electric kettle, a dishwasher, a washing machine, a cooker with a water tank or a coffee maker.More generally, the 12 electric fluid heating system can be any system designed to heat a fluid, particularly water, for various purposes, whether domestic or industrial.

[0052] It should be noted that in order to meet various requirements in terms of temperature and volume of fluid to be heated, several heating devices 10 can be mounted on the same container 11.

[0053] Referring to [Fig. 4], a method for electrically heating a fluid received in the container 11 includes a step 40 of mounting the sleeve 2 on the container 11 such that the sleeve 2 extends inside the container 11 from one of its walls. For example, the sleeve 2 is mounted on the bottom wall from below the container 11 or on a side wall of the container 11.

[0054] In the case of a modification to an existing electric fluid heating system 12, such as an electric water heater, it is possible to use the existing sheath 2. In other words, the container 11 may already have a sheath 2 extending from a wall of the container into its interior.

[0055] The heating method further includes a step of disposing of the sodium lamp 1, in particular high pressure, in the sheath 2. The sheath 2 has, in fact, an access opening located outside the container 11 (or accessible from outside the container 11), allowing the insertion of the sodium lamp 1 into the sheath 2.

[0056] In order to accelerate the heat transfer to the liquid to be heated received in the container 11, a step of arranging a perforated metal casing 5, at least partially enveloping the sodium lamp 1 in the sleeve 2, can be envisaged. This perforated metal casing 5 is, in one embodiment, cylindrical in shape, such as a sieve cylinder or one or more windings of conductive wire around the sodium lamp 1.

[0057] During an ignition step 42 of the sodium lamp, the sleeve 2 transmits to the fluid received in the container 11 heat generated by the sodium lamp 1 lit in the sleeve 2.

[0058] Advantageously, the embodiments described above offer 12 electric fluid heating systems, including electric water heaters, with increased energy efficiency, ease of maintenance, and optimal service life.

Claims

Demands

1. A heating device (10) intended to be mounted on a container (11) arranged to receive a fluid to be heated, this heating device (10) comprising - a sleeve (2) intended to be mounted on the container (11) such that this sleeve (2) extends inside the container (11) from a wall of this container (11); - a sodium lamp (1) intended to be placed in the sleeve (2), this sleeve (2) being configured to transmit to the fluid received in the container (11) heat generated by the sodium lamp (1) when it is lit in the sleeve (2).

2. Heating device (10) according to the preceding claim, characterized in that the sodium lamp (1) is a high-pressure sodium lamp (1).

3. Heating device (10) according to claim 1 or 2, characterized in that it further comprises a perforated metal casing (5) intended to at least partially enclose the sodium lamp (1) in the sheath (2).

4. A heating device (10) according to any one of the preceding claims, characterized in that it further comprises a means (4) for removably placing the sodium lamp (1) in the sheath (2).

5. A heating device (10) according to any one of the preceding claims, characterized in that it further comprises a thermally insulating cap for closing the sheath (2), this cap being at least partially opaque to the light emitted by the sodium lamp (1).

6. Electric fluid heating system (12) comprising - a container (11) for receiving a fluid to be heated; - the heating device (10) of any one of the preceding claims.

7. Electric fluid heating system (12) according to the preceding claim, characterized in that it is an electric water heater, an instantaneous water heater, an electric storage boiler, an instantaneous electric boiler, an electric steam boiler, or a household appliance designed to heat a fluid.

8. Electric fluid heating system (12) according to claim 6, characterized in that the container (11) is a tank, a heat exchanger or a fluid circulation duct.

9. Method of electrically heating a fluid received in a container (11) having a sheath (2) extending inside the container from a wall of the container (11), the method comprising the following steps: - disposition (41) of a sodium lamp (1) in the sheath (2); - ignition (42) of the sodium lamp (1) disposed in the sheath (2), the sheath (2) being configured to transmit to the fluid received in the container (11) heat generated by the lit sodium lamp (1).

10. Method of electrically heating a fluid according to the preceding claim, characterized in that it further comprises a step of disposing of a perforated metallic envelope (5) enveloping at least partially the sodium lamp (1) in the sheath (2).