EP0351300A1 - Microwave heating device for a flowing fluid - Google Patents

Microwave heating device for a flowing fluid Download PDF

Info

Publication number
EP0351300A1
EP0351300A1 EP89401976A EP89401976A EP0351300A1 EP 0351300 A1 EP0351300 A1 EP 0351300A1 EP 89401976 A EP89401976 A EP 89401976A EP 89401976 A EP89401976 A EP 89401976A EP 0351300 A1 EP0351300 A1 EP 0351300A1
Authority
EP
European Patent Office
Prior art keywords
liquid
heated
generator
exchanger
hollow member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89401976A
Other languages
German (de)
French (fr)
Inventor
Jean-Claude Deronzier
Bernard Martel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP0351300A1 publication Critical patent/EP0351300A1/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/80—Apparatus for specific applications
    • H05B6/802—Apparatus for specific applications for heating fluids

Definitions

  • the present invention relates to a device for heating a liquid in circulation by microwave. It applies in particular to the heating of water or liquids such as oils, liqueurs or even milk.
  • microwaves are high frequency electromagnetic waves which can be emitted by an appropriate generator, for example of the magnetron type.
  • This generator powered by an electric current, converts the electric energy brought by this current into electromagnetic energy.
  • the microwaves emitted by the generator cause, in a liquid such as water for example, oscillations of the molecules of this liquid, namely a pivoting of each molecule by 180 ° followed by a return to its initial position, the frequency of said oscillations being equal to the frequency of microwaves.
  • the molecules therefore oscillate 2450.106 times per second.
  • a device for heating circulating water by microwave is already known.
  • This device is used by manufacturers of microwave generators to measure the performance of these generators.
  • Such a known device is schematically represented in FIG. 1 and comprises, in addition to a microwave generator 2, for example of the magnetron type, a low voltage / high voltage transformer 4 provided for the power supply of the magnetron (the latter requiring a high supply voltage which can be 2500 V, 4000 V or 6000 V for example).
  • the electrical energy thus received by the magnetron is transformed by the latter into electromagnetic energy in the form of a microwave flux.
  • the device also comprises a waveguide 6 which conducts the microwaves, as well as a hollow member 8 which is called “water charge” or “applicator” and which is transparent to microwaves.
  • This hollow member has two open ends respectively forming an inlet and an outlet of said member. The latter is connected to the microwave generator via the waveguide 6.
  • a pipe 10 for the arrival of the liquid to be heated - in this case water - is connected to the inlet of the hollow member 8 and a pipe 12 for discharging this liquid is connected to the outlet of this hollow member 8 so that the liquid to be heated can circulate through this hollow member.
  • the energy of the microwaves is thus communicated to the water which passes through the hollow member and which heats up from an inlet temperature Te to an outlet temperature Ts greater than Te.
  • the device further comprises a metal part 14, for example made of copper, which is mounted on the waveguide 6 and called a "charge adapter".
  • This part whose position is adjustable, makes it possible to adapt the water charge to the waveguide 6 to prevent the reflection of part of the microwave flow towards the generator 2.
  • the hollow member 8 consists of a tube in the form of a straight cylinder, which is for example made of a plastic material or of a ceramic transparent to these microwaves.
  • the heating efficiency is a very important factor since it directly affects energy consumption.
  • the efficiency of industrial microwave generators is low, of the order of 50% to 60%.
  • French patent FR-A-2 483 158 describes a microwave heating device which comprises a water charge of complicated shape (in the shape of a horseshoe).
  • This exchanger 16 is for example constituted by a coil 17 which is placed in the body of the generator and in which is intended to circulate a cooling fluid such as water for example.
  • the inlet of the exchanger 16 is connected to a pipe 18 for the arrival of coolant (cold water) and its outlet is connected to a pipe 20 allowing the evacuation of the heated coolant, when passing through the exchanger 16, by the heat given off by the microwave generator.
  • the present invention aims to improve the efficiency of devices for heating liquids in circulation by microwave to achieve efficiencies of the order of 90% or more, without using a hollow member of complicated shape.
  • the present invention uses the heat lost in cooling the microwave generator to heat the circulating liquid before the latter is heated in the hollow member.
  • the subject of the present invention is a device for heating a liquid in circulation by microwaves, this device comprising: - a microwave generator, - a waveguide intended to transmit the microwaves produced by the generator, - a hollow and transparent organ in the microwave having two open ends which respectively form an inlet and an outlet of said member, the liquid to be heated being intended to circulate from the inlet to the outlet of the member, the latter being electromagnetically coupled to the generator via the waveguide so that the liquid is heated by microwaves when it passes through the hollow member, and - a heat exchanger which allows the cooling of the microwave generator by circulation of a cooling fluid in this exchanger, device characterized in that it further comprises means of thermal coupling of the generator to the hollow member, these thermal coupling means being provided so that the liquid to be heated circulates therein and is heated there due to the heat given off by the generator, before circulating in the hollow organ and being heated there by microwaves.
  • the thermal coupling means comprise said heat exchanger and a pipe connecting the outlet of the latter at the inlet of the hollow member, the liquid to be heated being intended to circulate from the inlet of said heat exchanger to the outlet of the hollow member and therefore also serving as coolant for the generator.
  • the thermal coupling means comprise another heat exchanger comprising: - a primary circuit whose input is connected to the output of the heat exchanger allowing the cooling of the microwave generator, and which is therefore intended to be traversed by the cooling fluid, the latter being heated by passage through the heat exchanger allowing the cooling of the microwave generator, and a secondary circuit which is thermally coupled to the primary circuit and the outlet of which is connected to the inlet of the hollow member by a pipe, the liquid to be heated being intended to circulate from the inlet of the secondary circuit to the outlet of the 'hollow organ.
  • This second particular embodiment is particularly suitable for heating corrosive liquids such as acids or strong bases.
  • the secondary circuit of said other heat exchanger and the pipe connecting this secondary circuit to the hollow member are designed for the circulation of such corrosive liquids, that is to say so as not to be damaged by them.
  • the device which is the subject of the invention may further comprise an additional heat exchanger provided for recovering heat from the liquid heated in the device, after using this liquid, and for heating, with this heat, this same liquid before entering the device.
  • FIG. 1 is a schematic view of a known device for heating circulating water by microwaves and has already been described
  • FIG. 2 is a schematic view of a first particular embodiment of the device which is the subject of the invention
  • FIG. 3 is a schematic view of a second particular embodiment of the device which is the subject of the invention
  • FIGS. 4 and 5 are schematic views of improvements made respectively to the devices of FIGS. 2 and 3.
  • Figure 2 there is shown schematically a first particular embodiment of the device object of the invention.
  • the device shown diagrammatically in FIG. 2 can be used for example for heating water and in accordance with the device which is shown in FIG. 1 except that the pipes 10 and 20 of this latter device are replaced, in the device which is shown on FIG. 2, by a pipe 22 which connects the outlet of the heat exchanger 16 to the inlet of the hollow member 8.
  • the water to be heated also serves as cooling fluid for the microwave generator 2 and circulates in the following way in the device: it arrives in the exchanger 16 via the pipe 18, passes through this exchanger, the pipe 22 and the organ hollow 8 from which it emerges through the pipe 12. The water thus successively passes through the exchanger 16 and the hollow member 8 in which it is heated.
  • the microwave generator 2 has an efficiency of the order of 50%, the heat flux F1 dissipated in the exchanger 16 is substantially equal to the heat flux F2 dissipated in the hollow member 8. Therefore, the heating of the water in the exchanger 16 is substantially the same as that which takes place in the water charge.
  • the temperature T1s is therefore substantially equal to the half-sum of Te and Ts.
  • the yield of the device shown in FIG. 2 is equal to: Q.Cp. (Ts-Te) .Pc ⁇ 1 .860 ⁇ 1 formula in which Q, Cp and Pc respectively represent the flow of water (expressed in kg / h), the specific heat of the water, which is worth approximately 1 kcal / (kg. ° c), and the power consumed by the generator and the power supply transformer of the latter (expressed in kW), Ts and Te being expressed in ° C.
  • the efficiency of the device which is represented schematically in FIG. 2 is greater than the efficiency of the device which is schematically represented in FIG. 1, that is to say the efficiency of the microwave generator, for the same liquid to be heated, the same flow rate Q of this liquid and the same power Pc of course.
  • this efficiency can be limited by the fact that the temperature of the cooling fluid at the outlet of the heat exchanger 16 must not exceed 80 ° C. for certain microwave generators, the flow rate Q having to be adjusted accordingly. .
  • FIG 3 there is shown schematically another device according to the invention.
  • This other device is particularly suited to the case where the liquid to be heated is very corrosive and therefore incompatible with the circuit of the exchanger 16 allowing the cooling of the microwave generator.
  • This corrosive liquid is for example an acid or a strong base.
  • the device of Figure 2 can be used to heat certain liquids which are not too corrosive, provided that the exchanger 16 is suitable for such liquids: one can use a metal exchanger 16 whose internal coating is made of fluorinated resin.
  • the device which is schematically shown in Figure 3 differs from the device which is shown in Figure 1 in that it further comprises another heat exchanger 24.
  • This is made of a material which resists the corrosive liquid to heating, for example a metallic material such as titanium, stainless steel or tantalum, or even a plastic material such as polypropylene, polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE).
  • the heat exchanger 24 is provided for transferring heat which has been communicated to the cooling fluid of the microwave generator, to the liquid to be heated, and comprises a primary circuit 25 the inlet of which is connected to the outlet of the exchanger 16 by a pipe 26 and the outlet of which is connected to a pipe 28 for discharging the cooling fluid which is for example a liquid such as water.
  • This primary circuit is therefore integrated into the cooling circuit of the microwave generator 2: the coolant enters the exchanger 16 through the pipe 18, heats up in this exchanger 16, travels through the pipe 26, then the primary circuit of the exchanger 24 from which it leaves via the pipe 28 serving for its evacuation.
  • the exchanger 24 also comprises a secondary circuit 30, for example in the form of a coil, the inlet of which is connected to a pipe 32 for the arrival of the corrosive liquid to be heated in the device and the outlet of which is connected to the inlet of the hollow member 8 via a pipe 34.
  • the secondary circuit is thermally coupled to the primary circuit.
  • the primary circuit has for example the shape of a tank which comprises at one of its two ends an opening for entering the coolant and at its other end, an opening for leaving the coolant.
  • the secondary circuit passes through this tank in a sealed manner, the coil that this secondary circuit comprises being inside the tank.
  • the liquid to be heated arrives in the secondary circuit through the end of the tank from which the coolant comes out and therefore leaves the secondary circuit through the end of the tank where the coolant enters.
  • the liquid to be heated in the device thus arrives in the secondary circuit of the exchanger 24 via the pipe 32, heats up in this exchanger 24 by heat exchange with the primary circuit in which the liquid having served to cool the microwave generator 2 circulates and leaves the exchanger 24 to reach the hollow member 8 via the pipe 34.
  • the liquid to be heated in the device heats up even more due to the microwaves and leaves the hollow member through the pipe 12.
  • the flow rate of the coolant of the microwave generator is preferably adjusted in such a way that its temperature T3s at the outlet of the exchanger 16 is as high as possible in order to reduce the size of the exchanger 24 as much as possible. Indeed, it is sought to obtain a maximum difference T3s-T1e between the temperature T3s of the coolant at its outlet from the exchanger 16 and the temperature T1e of the cold liquid, at the inlet of the secondary circuit. It must however be taken into account, as already indicated above, that for certain microwave generators the temperature T3s of the coolant must not exceed 80 ° C at the outlet of the exchanger 16.
  • the device represented in FIG. 3 also makes it possible to obtain a higher yield than that of the device which is represented in FIG. 1.
  • the present invention therefore allows an extremely high yield increase, close to 80%.
  • the pipes 22 ( Figure 2), 26 and 34 ( Figure 3) are made in such a way that the liquids which circulate there lose as little heat as possible.
  • the pipes in question can be provided with heat-insulating means (not shown).
  • the device shown diagrammatically in FIG. 4 is an improvement on the device in FIG. 2 and makes it possible to increase the temperature of the liquid to be heated before it enters the device. More precisely, this liquid, once heated, leaves the device via the pipe 12 runs through an installation 36 in which it is used and ends up in a recovery tank 38.
  • the device of FIG. 4 is identical to that of FIG. 2 with , in addition, a heat exchanger 40 of which the primary circuit is traversed by the liquid coming from the recovery tank and the secondary circuit of which is traversed by the liquid to be heated in the device, prior to its entry into this device by the pipe 18.
  • the liquid which it is desired to heat in the device is it preheated in the exchanger 40 thanks to the still hot liquid from the tank 38 which, after passing through the exchanger 40, arrives at a storage tank 42 from which it is then discharged.
  • the exchanger 40 which has just been described makes it possible to reduce the electric power consumed by the microwave generator 2 -and therefore the operating cost of the installation shown in FIG. 2 for the same device output temperature Ts.
  • the reduction in power consumed can be of the order of 25% for heating ultra-pure water up to 80 ° C.
  • the exchanger 16 of the magnetron 2 can be, in this case, a metal exchanger having an internal coating constituted by a fluorinated resin and the heat exchanger 40 is for example made of a plastic material such as PVDF.
  • the temperature of the liquid coming from the tank 38 must be high enough to obtain a significant preheating.
  • a temperature at least equal to 60 ° C. for the water coming from tank 38 is acceptable.
  • the exchanger 40 is adapted to this liquid and added to the device shown in Figure 3, which leads to the device shown in Figure 5: the liquid from the tank 38 passes through the primary circuit of the exchanger 40 then ends up at the tank storage 42 and the aggressive liquid that is to be preheated travels through the secondary circuit of the exchanger 40 and then leads to the inlet of the secondary circuit of the exchanger 24 (adapted to the aggressive liquid considered) via the pipe 32 .
  • the coolant of the generator 2 can be a gas, air for example, when the exchanger 24 is used (and chosen to allow the transfer of heat from a gas to a liquid).
  • the present invention has many applications in a wide variety of fields. It applies in particular to the production of domestic or industrial water heaters (household appliance sector), to the heating of ultra pure water (microelectronics sector), to the heating of demineralized water (pharmacy sector) , medicine), the heating of aggressive acid solutions (chemical sector) and the heating of oils, liqueurs or liquid dairy products (food industry).

Abstract

This device comprises a microwave generator (2), a waveguide (6) intended to transmit the microwaves, a unit (8) which is hollow and transparent to the microwaves, from the entrance to the exit of which the fluid is intended to flow, and which is connected to the generator by the waveguide so that the fluid is heated by the microwaves on crossing the hollow unit, a heat exchanger (16) which allows the cooling of the generator by flow of a cooling fluid in this exchanger and means (16, 22) for thermal coupling of the generator to the hollow unit, which are provided so that the fluid to be heated flows in these means and is heated therein before flowing into the hollow unit. <IMAGE>

Description

La présente invention concerne un dispositif de chauffage d'un liquide en circulation par micro-­ondes. Elle s'applique notamment au chauffage de l'eau ou de liquides tels que les huiles, les liqueurs ou encore le lait.The present invention relates to a device for heating a liquid in circulation by microwave. It applies in particular to the heating of water or liquids such as oils, liqueurs or even milk.

On sait que les micro-ondes sont des ondes électromagnétiques de haute fréquence qui peuvent être émises par un générateur approprié par exemple de type magnétron. Ce générateur, alimenté par un courant électrique, convertit l'énergie électrique apportée par ce courant en énergie électromagnétique. Les micro-­ondes émises par le générateur provoquent, dans un liquide tel que l'eau par exemple, des oscillations des molécules de ce liquide, à savoir un pivotement de chaque molécule de 180° suivi d'un retour à sa position initiale, la fréquence desdites oscillations étant égale à la fréquence des micro-ondes. Pour la fréquence généralement adoptée de 2450 MHz, les molécules oscillent donc 2450.10⁶ fois par seconde. Ces oscillations extrêmement rapides provoquent des frictions des molécules les unes contre les autres et il en résulte un chauffage de l'eau.It is known that microwaves are high frequency electromagnetic waves which can be emitted by an appropriate generator, for example of the magnetron type. This generator, powered by an electric current, converts the electric energy brought by this current into electromagnetic energy. The microwaves emitted by the generator cause, in a liquid such as water for example, oscillations of the molecules of this liquid, namely a pivoting of each molecule by 180 ° followed by a return to its initial position, the frequency of said oscillations being equal to the frequency of microwaves. For the generally adopted frequency of 2450 MHz, the molecules therefore oscillate 2450.10⁶ times per second. These extremely fast oscillations cause friction of the molecules against each other and this results in heating of the water.

On connaît déjà un dispositif de chauffage d'eau en circulation par micro-ondes. Ce dispositif est utilisé par les fabricants de générateurs de micro-­ondes pour mesurer le rendement de ces générateurs. Un tel dispositif connu est schématiquement représenté sur la figure 1 et comprend, outre un générateur de micro-­ondes 2 par exemple du type magnétron, un transformateur 4 basse tension/haute tension prévu pour l'alimentation électrique du magnétron (ce dernier nécessitant une tension d'alimentation élevée qui peut être de 2500 V, 4000 V ou 6000 V par exemple). L'énergie électrique ainsi reçue par le magnétron est transformée par ce dernier en énergie électromagnétique sous la forme d'un flux de micro-ondes.A device for heating circulating water by microwave is already known. This device is used by manufacturers of microwave generators to measure the performance of these generators. Such a known device is schematically represented in FIG. 1 and comprises, in addition to a microwave generator 2, for example of the magnetron type, a low voltage / high voltage transformer 4 provided for the power supply of the magnetron (the latter requiring a high supply voltage which can be 2500 V, 4000 V or 6000 V for example). The electrical energy thus received by the magnetron is transformed by the latter into electromagnetic energy in the form of a microwave flux.

Le dispositif comprend également un guide d'ondes 6 qui conduit les micro-ondes, ainsi qu'un organe creux 8 qui est appelé "charge à eau" ou "applicateur" et qui est transparent aux micro-ondes. Cet organe creux a deux extrémités ouvertes formant respectivement une entrée et une sortie dudit organe. Ce dernier est relié au générateur de micro-ondes par l'intermédiaire du guide d'onde 6. Une canalisation 10 d'arrivée du liquide à chauffer -en l'occurrence de l'eau- est reliée à l'entrée de l'organe creux 8 et une canalisation 12 d'évacuation de ce liquide est reliée à la sortie de cet organe creux 8 de façon que le liquide à chauffer puisse circuler à travers cet organe creux.The device also comprises a waveguide 6 which conducts the microwaves, as well as a hollow member 8 which is called "water charge" or "applicator" and which is transparent to microwaves. This hollow member has two open ends respectively forming an inlet and an outlet of said member. The latter is connected to the microwave generator via the waveguide 6. A pipe 10 for the arrival of the liquid to be heated - in this case water - is connected to the inlet of the hollow member 8 and a pipe 12 for discharging this liquid is connected to the outlet of this hollow member 8 so that the liquid to be heated can circulate through this hollow member.

L'énergie des micro-ondes est ainsi communiquée à l'eau qui traverse l'organe creux et qui s'échauffe d'une température d'entrée Te à une température de sortie Ts supérieure à Te.The energy of the microwaves is thus communicated to the water which passes through the hollow member and which heats up from an inlet temperature Te to an outlet temperature Ts greater than Te.

Le dispositif comprend en outre une pièce métallique 14 par exemple en cuivre, qui est montée sur le guide d'ondes 6 et appelée "adaptateur de charge". Cette pièce, dont la position est réglable, permet d'adapter la charge à eau au guide d'onde 6 pour empêcher la réflexion d'une partie du flux de micro-­ondes vers le générateur 2.The device further comprises a metal part 14, for example made of copper, which is mounted on the waveguide 6 and called a "charge adapter". This part, whose position is adjustable, makes it possible to adapt the water charge to the waveguide 6 to prevent the reflection of part of the microwave flow towards the generator 2.

Dans la plupart des cas, l'organe creux 8 est constitué par un tube en forme de cylindre droit, qui est par exemple fait d'une matière plastique ou d'une céramique transparente à ces micro-ondes.In most cases, the hollow member 8 consists of a tube in the form of a straight cylinder, which is for example made of a plastic material or of a ceramic transparent to these microwaves.

Dans beaucoup de procédés industriels, le rendement de chauffage est un facteur très important puiqu'il intervient directement sur la consommation énergétique. Or, le rendement des générateurs de micro-­ondes industriels est faible, de l'ordre de 50% à 60%.In many industrial processes, the heating efficiency is a very important factor since it directly affects energy consumption. However, the efficiency of industrial microwave generators is low, of the order of 50% to 60%.

Ceci signifie qu'environ 40% à 50% de l'énergie électrique servant à alimenter ces générateurs est perdue dans le refroidissement nécessaire à ceux-ci.This means that approximately 40% to 50% of the electrical energy used to power these generators is lost in the cooling necessary for them.

Des recherches ont été faites en vue d'augmenter le rendement des générateurs de micro-­ondes. En particulier, le brevet français FR-A-2 483 158 décrit un dispositif de chauffage par micro-ondes qui comporte une charge à eau de forme compliquée (en forme de fer à cheval).Research has been done to increase the efficiency of microwave generators. In particular, French patent FR-A-2 483 158 describes a microwave heating device which comprises a water charge of complicated shape (in the shape of a horseshoe).

Par ailleurs, il est connu, notamment dans le cas d'un générateur de micro-ondes de forte puissance (supérieure à environ 3kW par exemple), de munir ce générateur d'un échangeur de chaleur 16 destiné à refroidir le générateur. Cet échangeur 16 est par exemple constitué par un serpentin 17 qui est placé dans le corps du générateur et dans lequel est destiné à circuler un fluide de refroidissement tel que l'eau par exemple. L'entrée de l'échangeur 16 est reliée à une canalisation 18 d'arrivée de fluide de refroidissement (eau froide) et sa sortie est reliée à une canalisation 20 permettant l'évacuation du fluide de refroidissement chauffé, lors de la traversée de l'échangeur 16, par la chaleur dégagée par le générateur de micro-ondes.Furthermore, it is known, in particular in the case of a high-power microwave generator (greater than approximately 3 kW, for example), to provide this generator with a heat exchanger 16 intended to cool the generator. This exchanger 16 is for example constituted by a coil 17 which is placed in the body of the generator and in which is intended to circulate a cooling fluid such as water for example. The inlet of the exchanger 16 is connected to a pipe 18 for the arrival of coolant (cold water) and its outlet is connected to a pipe 20 allowing the evacuation of the heated coolant, when passing through the exchanger 16, by the heat given off by the microwave generator.

La présente invention vise à améliorer le rendement des dispositifs de chauffage de liquides en circulation par micro-ondes pour atteindre des rendements de l'ordre de 90% ou plus, sans utiliser un organe creux de forme compliquée.The present invention aims to improve the efficiency of devices for heating liquids in circulation by microwave to achieve efficiencies of the order of 90% or more, without using a hollow member of complicated shape.

Pour ce faire, la présente invention utilise la chaleur perdue dans le refroidissement du générateur de micro-ondes pour chauffer le liquide en circulation avant que ce dernier ne soit chauffé dans l'organe creux.To do this, the present invention uses the heat lost in cooling the microwave generator to heat the circulating liquid before the latter is heated in the hollow member.

De façon précise, la présente invention a pour objet un dispositif de chauffage d'un liquide en circulation par des micro-ondes, ce dispositif comprenant :
- un générateur de micro-ondes,
- un guide d'ondes destiné à transmettre les micro-ondes produites par le générateur,
- un organe creux et transparent aux micro-­ondes ayant deux extrémités ouvertes qui forment respectivement une entrée et une sortie dudit organe, le liquide à chauffer étant destiné à circuler de l'entrée à la sortie de l'organe, ce dernier étant couplé électromagnétiquement au générateur par l'intermédiaire du guide d'ondes de sorte que le liquide est chauffé par les micro-ondes lorsqu'il traverse l'organe creux, et
- un échangeur de chaleur qui permet le refroidissement du générateur de micro-ondes par circulation d'un fluide de refroidissement dans cet échangeur,
dispositif caractérisé en ce qu'il comprend en outre des moyens de couplage thermique du générateur à l'organe creux, ces moyens de couplage thermique étant prévus pour que le liquide à chauffer y circule et y soit chauffé du fait de la chaleur dégagée par le générateur, avant de circuler dans l'organe creux et d'y être chauffé par les micro-ondes.Specifically, the subject of the present invention is a device for heating a liquid in circulation by microwaves, this device comprising:
- a microwave generator,
- a waveguide intended to transmit the microwaves produced by the generator,
- a hollow and transparent organ in the microwave having two open ends which respectively form an inlet and an outlet of said member, the liquid to be heated being intended to circulate from the inlet to the outlet of the member, the latter being electromagnetically coupled to the generator via the waveguide so that the liquid is heated by microwaves when it passes through the hollow member, and
- a heat exchanger which allows the cooling of the microwave generator by circulation of a cooling fluid in this exchanger,
device characterized in that it further comprises means of thermal coupling of the generator to the hollow member, these thermal coupling means being provided so that the liquid to be heated circulates therein and is heated there due to the heat given off by the generator, before circulating in the hollow organ and being heated there by microwaves.

Selon un premier mode de réalisation particulier du dispositif objet de l'invention, les moyens de couplage thermique comprennent ledit échangeur de chaleur et une canalisation reliant la sortie de celui-ci à l'entrée de l'organe creux, le liquide à chauffer étant destiné à circuler de l'entrée dudit échangeur de chaleur à la sortie de l'organe creux et servant donc aussi de fluide de refroidissement du générateur.According to a first particular embodiment of the device which is the subject of the invention, the thermal coupling means comprise said heat exchanger and a pipe connecting the outlet of the latter at the inlet of the hollow member, the liquid to be heated being intended to circulate from the inlet of said heat exchanger to the outlet of the hollow member and therefore also serving as coolant for the generator.

Selon un second mode de réalisation particulier du dispositif objet de l'invention, les moyens de couplage thermique comprennent un autre échangeur de chaleur comportant :
- un circuit primaire dont l'entrée est reliée à la sortie de l'échangeur de chaleur permettant le refroidissement du générateur de micro-ondes, et qui est donc destiné à être traversé par le fluide de refroidissement, ce dernier étant chauffé par passage dans l'échangeur de chaleur permettant le refroidissement du générateur de micro-ondes, et
- un circuit secondaire qui est couplé thermiquement au circuit primaire et dont la sortie est reliée à l'entrée de l'organe creux par une canalisation, le liquide à chauffer étant destiné à circuler de l'entrée du circuit secondaire à la sortie de l'organe creux.According to a second particular embodiment of the device which is the subject of the invention, the thermal coupling means comprise another heat exchanger comprising:
- a primary circuit whose input is connected to the output of the heat exchanger allowing the cooling of the microwave generator, and which is therefore intended to be traversed by the cooling fluid, the latter being heated by passage through the heat exchanger allowing the cooling of the microwave generator, and
a secondary circuit which is thermally coupled to the primary circuit and the outlet of which is connected to the inlet of the hollow member by a pipe, the liquid to be heated being intended to circulate from the inlet of the secondary circuit to the outlet of the 'hollow organ.

Ce second mode de réalisation particulier est particulièrement adapté au chauffage de liquides corrosifs tels que des acides ou des bases fortes.This second particular embodiment is particularly suitable for heating corrosive liquids such as acids or strong bases.

De préférence, le circuit secondaire dudit autre échangeur de chaleur et la canalisation reliant ce circuit secondaire à l'organe creux sont conçus pour la circulation de tels liquides corrosifs, c'est-à-dire pour ne pas être endommagés par ceux-ci.Preferably, the secondary circuit of said other heat exchanger and the pipe connecting this secondary circuit to the hollow member are designed for the circulation of such corrosive liquids, that is to say so as not to be damaged by them.

Enfin, le dispositif objet de l'invention peut comprendre en outre un échangeur de chaleur supplémentaire prévu pour récupérer de la chaleur du liquide chauffé dans le dispositif, après utilisation de ce liquide, et pour chauffer, avec cette chaleur, ce même liquide avant son entrée dans le dispositif.Finally, the device which is the subject of the invention may further comprise an additional heat exchanger provided for recovering heat from the liquid heated in the device, after using this liquid, and for heating, with this heat, this same liquid before entering the device.

La présente invention sera mieux comprise à la lecture de la description qui suit, d'exemples de réalisation donnés à titre purement indicatif et nullement limitatif, en référence aux dessins annexés sur lesquels :
- la figure 1 est une vue schématique d'un dispositif connu de chauffage d'eau en circulation par des micro-ondes et a déjà été décrite,
- la figure 2 est une vue schématique d'un premier mode de réalisation particulier du dispositif objet de l'invention,
- la figure 3 est une vue shématique d'un second mode de réalisation particulier du dispositif objet de l'invention, et
les figures 4 et 5 sont des vues schématiques de perfectionnements respectivement apportés aux dispositifs des figures 2 et 3.The present invention will be better understood on reading the description which follows, of exemplary embodiments given purely by way of indication and in no way limiting, with reference to the appended drawings in which:
FIG. 1 is a schematic view of a known device for heating circulating water by microwaves and has already been described,
FIG. 2 is a schematic view of a first particular embodiment of the device which is the subject of the invention,
FIG. 3 is a schematic view of a second particular embodiment of the device which is the subject of the invention, and
FIGS. 4 and 5 are schematic views of improvements made respectively to the devices of FIGS. 2 and 3.

Sur la figure 2 on a représenté schématiquement un premier mode de réalisation particulier du dispositif objet de l'invention.In Figure 2 there is shown schematically a first particular embodiment of the device object of the invention.

Le dispositif schématiquement représenté sur la figure 2 est utilisable par exemple pour le chauffage d'eau et conforme au dispositif qui est représenté sur la figure 1 excepté que les canalisations 10 et 20 de ce dernier dispositif sont remplacées, dans le dispositif qui est représenté sur la figure 2, par une canalisation 22 qui relie la sortie de l'échangeur de chaleur 16 à l'entrée de l'organe creux 8.The device shown diagrammatically in FIG. 2 can be used for example for heating water and in accordance with the device which is shown in FIG. 1 except that the pipes 10 and 20 of this latter device are replaced, in the device which is shown on FIG. 2, by a pipe 22 which connects the outlet of the heat exchanger 16 to the inlet of the hollow member 8.

En outre, l'eau à chauffer sert également de fluide de refroidissement du générateur de micro-ondes 2 et circule de la façon suivante dans le dispositif : elle arrive dans l'échangeur 16 par la canalisation 18, traverse cet échangeur, la canalisation 22 et l'organe creux 8 dont elle ressort par la canalisation 12. L'eau traverse ainsi successivement l'échangeur 16 et l'organe creux 8 dans lesquels elle est chauffée.In addition, the water to be heated also serves as cooling fluid for the microwave generator 2 and circulates in the following way in the device: it arrives in the exchanger 16 via the pipe 18, passes through this exchanger, the pipe 22 and the organ hollow 8 from which it emerges through the pipe 12. The water thus successively passes through the exchanger 16 and the hollow member 8 in which it is heated.

Si le générateur de micro-ondes 2 a un rendement de l'ordre de 50%, le flux thermique F1 dissipé dans l'échangeur 16 est sensiblement égal au flux thermique F2 dissipé dans l'organe creux 8. De ce fait, l'échauffement de l'eau dans l'échangeur 16 est sensiblement le même que celui qui a lieu dans la charge à eau.If the microwave generator 2 has an efficiency of the order of 50%, the heat flux F1 dissipated in the exchanger 16 is substantially equal to the heat flux F2 dissipated in the hollow member 8. Therefore, the heating of the water in the exchanger 16 is substantially the same as that which takes place in the water charge.

En désignant respectivement par Te, T1s et Ts la température de l'eau à l'entrée de l'échangeur 16, la température de l'eau à la sortie de cet échangeur et la température de l'eau à la sortie de l'organe creux 8, la température T1s est donc sensiblement égale à la demi-somme de Te et Ts.By designating respectively by Te, T1s and Ts the temperature of the water at the inlet of the exchanger 16, the temperature of the water at the outlet of this exchanger and the temperature of the water at the outlet of the hollow member 8, the temperature T1s is therefore substantially equal to the half-sum of Te and Ts.

Or, le rendement du dispositif représenté sur la figure 2 est égal à :
Q.Cp.(Ts-Te).Pc⁻¹ .860⁻¹
formule dans laquelle Q, Cp et Pc représentent respectivement le débit de l'eau (exprimé en kg/h), la chaleur spécifique de l'eau, qui vaut environ 1 kcal/(kg.°c), et la puissance consommée par le générateur et le transformateur d'alimentation de ce dernier (exprimée en kW), Ts et Te étant exprimées en °C.However, the yield of the device shown in FIG. 2 is equal to:
Q.Cp. (Ts-Te) .Pc⁻¹ .860⁻¹
formula in which Q, Cp and Pc respectively represent the flow of water (expressed in kg / h), the specific heat of the water, which is worth approximately 1 kcal / (kg. ° c), and the power consumed by the generator and the power supply transformer of the latter (expressed in kW), Ts and Te being expressed in ° C.

On voit donc que le rendement du dispositif qui est représenté schématiquement sur la figure 2 est supérieur au rendement du dispositif qui est schématiquement représenté sur la figure 1, c'est-à-­dire au rendement du générateur de micro-ondes, pour un même liquide à chauffer, un même débit Q de ce liquide et une même puissance Pc bien entendu.It can therefore be seen that the efficiency of the device which is represented schematically in FIG. 2 is greater than the efficiency of the device which is schematically represented in FIG. 1, that is to say the efficiency of the microwave generator, for the same liquid to be heated, the same flow rate Q of this liquid and the same power Pc of course.

En effet, le rendement du générateur est seulement égal à :
Q.Cp.(Ts-T1s).Pc⁻¹.860⁻¹
Indeed, the generator efficiency is only equal to:
Q.Cp. (Ts-T1s) .Pc⁻¹.860⁻¹

On peut ainsi atteindre un rendement supérieur ou égal à 90% avec la présente invention.It is thus possible to achieve a yield greater than or equal to 90% with the present invention.

Toutefois, ce rendement peut être limité par le fait que la température du fluide de refroidissement à la sortie de l'échangeur de chaleur 16 ne doit pas excéder 80°C pour certains générateurs de micro-ondes, le débit Q devant être réglé en conséquence.However, this efficiency can be limited by the fact that the temperature of the cooling fluid at the outlet of the heat exchanger 16 must not exceed 80 ° C. for certain microwave generators, the flow rate Q having to be adjusted accordingly. .

Sur la figure 3, on a représenté schématiquement un autre dispositif conforme à l'invention. Cet autre dispositif est tout particulièrement adapté au cas où le liquide à chauffer est très corrrosif et par là même incompatible avec le circuit de l'échangeur 16 permettant le refroidissement du générateur de micro-ondes. Ce liquide corrosif est par exemple un acide ou une base forte. On notera toutefois que le dispositif de la figure 2 peut être utilisé pour chauffer certains liquides qui ne sont pas trop corrosifs, à condition que l'échangeur 16 soit adapté à de tels liquides : on peut utiliser un échangeur 16 métallique dont le revêtement interne est fait d'une résine fluorée.In Figure 3, there is shown schematically another device according to the invention. This other device is particularly suited to the case where the liquid to be heated is very corrosive and therefore incompatible with the circuit of the exchanger 16 allowing the cooling of the microwave generator. This corrosive liquid is for example an acid or a strong base. Note however that the device of Figure 2 can be used to heat certain liquids which are not too corrosive, provided that the exchanger 16 is suitable for such liquids: one can use a metal exchanger 16 whose internal coating is made of fluorinated resin.

Le dispositif qui est schématiquement représenté sur la figure 3 diffère du dispositif qui est représenté sur la figure 1 par le fait qu'il comporte en outre un autre échangeur de chaleur 24. Celui-ci est fait en un matériau qui résiste au liquide corrosif à chauffer, par exemple un matériau métallique tel que le titane, l'acier inoxydable ou le tantale, ou encore une matière plastique telle que le polypropylène, le polyfluorure de vinylidène (PVDF) ou le polytétrafluoréthylène (PTFE).The device which is schematically shown in Figure 3 differs from the device which is shown in Figure 1 in that it further comprises another heat exchanger 24. This is made of a material which resists the corrosive liquid to heating, for example a metallic material such as titanium, stainless steel or tantalum, or even a plastic material such as polypropylene, polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE).

L'échangeur de chaleur 24 est prévu pour transférer de la chaleur qui a été communiquée au fluide de refroidissement du générateur de micro-ondes, au liquide à chauffer, et comprend un circuit primaire 25 dont l'entrée est reliée à la sortie de l'échangeur 16 par une canalisation 26 et dont la sortie est reliée à une canalisation 28 d'évacuation du fluide de refroidissement qui est par exemple un liquide tel que l'eau. Ce circuit primaire est donc intégré au circuit de refroidissement du générateur 2 de micro-ondes : le liquide de refroidissement pénètre dans l'échangeur 16 par la canalisation 18, s'échauffe dans cet échangeur 16, parcourt la canalisation 26, puis le circuit primaire de l'échangeur 24 dont il sort par la canalisation 28 servant à son évacuation.The heat exchanger 24 is provided for transferring heat which has been communicated to the cooling fluid of the microwave generator, to the liquid to be heated, and comprises a primary circuit 25 the inlet of which is connected to the outlet of the exchanger 16 by a pipe 26 and the outlet of which is connected to a pipe 28 for discharging the cooling fluid which is for example a liquid such as water. This primary circuit is therefore integrated into the cooling circuit of the microwave generator 2: the coolant enters the exchanger 16 through the pipe 18, heats up in this exchanger 16, travels through the pipe 26, then the primary circuit of the exchanger 24 from which it leaves via the pipe 28 serving for its evacuation.

L'échangeur 24 comprend également un circuit secondaire 30, par exemple en forme de serpentin, dont l'entrée est reliée à une canalisation 32 d'arrivée du liquide corrosif à chauffer dans le dispositif et dont la sortie est reliée à l'entrée de l'organe creux 8 par l'intermédiaire d'une canalisation 34. Le circuit secondaire est couplé thermiquement au circuit primaire. A cet effet, le circuit primaire a par exemple la forme d'une cuve qui comporte à l'une de ses deux extrémités une ouverture d'entrée de liquide de refroidissement et à son autre extrémité, une ouverture de sortie de liquide de refroidissement. Le circuit secondaire traverse cette cuve de façon étanche, le serpentin que comporte ce circuit secondaire étant à l'intérieur de la cuve.The exchanger 24 also comprises a secondary circuit 30, for example in the form of a coil, the inlet of which is connected to a pipe 32 for the arrival of the corrosive liquid to be heated in the device and the outlet of which is connected to the inlet of the hollow member 8 via a pipe 34. The secondary circuit is thermally coupled to the primary circuit. For this purpose, the primary circuit has for example the shape of a tank which comprises at one of its two ends an opening for entering the coolant and at its other end, an opening for leaving the coolant. The secondary circuit passes through this tank in a sealed manner, the coil that this secondary circuit comprises being inside the tank.

De préférence, le liquide à chauffer arrive dans le circuit secondaire par l'extrémité de la cuve d'où sort le liquide de refroidissement et sort donc du circuit secondaire par l'extrémité de la cuve où pénètre le liquide de refroidissement.Preferably, the liquid to be heated arrives in the secondary circuit through the end of the tank from which the coolant comes out and therefore leaves the secondary circuit through the end of the tank where the coolant enters.

Le liquide à chauffer dans le dispositif arrive ainsi dans le circuit secondaire de l'échangeur 24 par la canalisation 32, se chauffe dans cet echangeur 24 par échange thermique avec le circuit primaire dans lequel circule le liquide ayant servi à refroidir le générateur 2 de micro-ondes et sort de l'échangeur 24 pour arriver à l'organe creux 8 par l'intermédiaire de la canalisation 34. En circulant dans cet organe creux 8, le liquide à chauffer dans le dispositif s'échauffe encore plus du fait des micro-­ondes et ressort de l'organe creux par la canalisation 12.The liquid to be heated in the device thus arrives in the secondary circuit of the exchanger 24 via the pipe 32, heats up in this exchanger 24 by heat exchange with the primary circuit in which the liquid having served to cool the microwave generator 2 circulates and leaves the exchanger 24 to reach the hollow member 8 via the pipe 34. In circulating in this hollow member 8, the liquid to be heated in the device heats up even more due to the microwaves and leaves the hollow member through the pipe 12.

Le débit du liquide de refroidissement du générateur de micro-ondes est de préférence réglé de telle manière que sa température T3s à la sortie de l'échangeur 16 soit la plus élevée possible afin de réduire au maximum la taille de l'échangeur 24. En effet, on cherche à obtenir un écart T3s-T1e maximum entre la température T3s du liquide de refroidissement à sa sortie de l'échangeur 16 et la température T1e du liquide froid, à l'entrée du circuit secondaire. Il faut toutefois tenir compte, comme on l'a déjà indiqué plus haut, du fait que pour certains générateurs de micro-ondes la température T3s du liquide de refroidissement ne doit pas dépasser 80°C à la sortie de l'échangeur 16.The flow rate of the coolant of the microwave generator is preferably adjusted in such a way that its temperature T3s at the outlet of the exchanger 16 is as high as possible in order to reduce the size of the exchanger 24 as much as possible. Indeed, it is sought to obtain a maximum difference T3s-T1e between the temperature T3s of the coolant at its outlet from the exchanger 16 and the temperature T1e of the cold liquid, at the inlet of the secondary circuit. It must however be taken into account, as already indicated above, that for certain microwave generators the temperature T3s of the coolant must not exceed 80 ° C at the outlet of the exchanger 16.

Le dispositif représenté sur la figure 3 permet également d'obtenir un rendement supérieur à celui du dispositif qui est représenté sur la figure 1.The device represented in FIG. 3 also makes it possible to obtain a higher yield than that of the device which is represented in FIG. 1.

Des essais effectués sur de l'eau domestique avec un dispositif conforme à celui de la figure 3, muni d'une charge à eau adaptée de forme cylindrique droite, en céramique, ont permis de vérifier les avantages de l'invention, avec les conditions suivantes :
- débit d'eau froide à chauffer dans le dispositif : Q=130kg/h (2,17 l/mn)
- température T1e : 12°C
- temperature de l'eau de refroidissement à sa sortie de l'échangeur 16 : T3s = 50°C
- température de sortie de la charge à eau : T4s = 54°C
- température de l'eau à chauffer, à sa sortie de l'échangeur 24 : T2s = 31°C
- puissance électrique consommée : Pc=7kW.Tests carried out on domestic water with a device conforming to that of FIG. 3, provided with a suitable water charge of straight cylindrical shape, made of ceramic, made it possible to verify the advantages of the invention, with the conditions following:
- flow of cold water to be heated in the device: Q = 130kg / h (2.17 l / min)
- temperature T1e: 12 ° C
- temperature of the cooling water at its outlet from the exchanger 16: T3s = 50 ° C
- outlet temperature of the water charge: T4s = 54 ° C
- temperature of the water to be heated, on leaving the exchanger 24: T2s = 31 ° C
- electrical power consumed: Pc = 7kW.

Le rendement du dispositif représenté sur la figure 3 est donc égal à :
Q.Cp.(T4s-T1e).Pc⁻¹.860⁻¹= 130x1x42x7⁻¹ x860⁻¹ =0,91 alors que le rendement du générateur de micro-ondes vaut :
Q.Cp.(T4s-T2s).Pc⁻¹ .860⁻¹ =130x1x23x7¹⁻ x860¹⁻ =0,5.The yield of the device shown in FIG. 3 is therefore equal to:
Q.Cp. (T4s-T1e) .Pc⁻¹.860⁻¹ = 130x1x42x7⁻¹ x860⁻¹ = 0.91 while the efficiency of the microwave generator is worth:
Q.Cp. (T4s-T2s) .Pc⁻¹ .860⁻¹ = 130x1x23x7¹⁻ x860¹⁻ = 0.5.

L'augmentation mesurée du rendement de chauffage est donc de l'ordre de :
(0,91 - 0,5) / 0,5 = 82%The measured increase in heating efficiency is therefore of the order of:
(0.91 - 0.5) / 0.5 = 82%

La présente invention permet donc une augmentation du rendement extrêmement élevée, voisine de 80%.The present invention therefore allows an extremely high yield increase, close to 80%.

Bien entendu, les canalisations 22 (figure 2), 26 et 34 (figure 3) sont réalisées de telle manière que les liquides qui y circulent y perdent le moins de chaleur possible. A cet effet, les canalisations en question peuvent être munies de moyens calorifuges (non représentés).Of course, the pipes 22 (Figure 2), 26 and 34 (Figure 3) are made in such a way that the liquids which circulate there lose as little heat as possible. To this end, the pipes in question can be provided with heat-insulating means (not shown).

Le dispositif représenté schématiquement sur la figure 4 est un perfectionnement du dispositif de la figure 2 et permet d'augmenter la température du liquide à chauffer préalablement à son entrée dans le dispositif. Plus précisément, ce liquide, une fois chauffé, sort du dispositif par la canalisation 12 parcourt une installation 36 dans laquelle il est utilisé et aboutit à un bac de récupération 38. Le dispositif de la figure 4 est identique à celui de la figure 2 avec, en plus, un échangeur de chaleur 40 dont le circuit primaire est parcouru par le liquide issu du bac de récupération et dont le circuit secondaire est parcouru par le liquide à chauffer dans le dispositif, préalablement à son entrée dans ce dispositif par la canalisation 18. Ainsi le liquide que l'on souhaite chauffer dans le dispositif est-il préchauffé dans l'échangeur 40 grâce au liquide encore chaud issu du bac 38 qui, après son passage dans l'échangeur 40, arrive à un bac de stockage 42 d'où il est ensuite évacué.The device shown diagrammatically in FIG. 4 is an improvement on the device in FIG. 2 and makes it possible to increase the temperature of the liquid to be heated before it enters the device. More precisely, this liquid, once heated, leaves the device via the pipe 12 runs through an installation 36 in which it is used and ends up in a recovery tank 38. The device of FIG. 4 is identical to that of FIG. 2 with , in addition, a heat exchanger 40 of which the primary circuit is traversed by the liquid coming from the recovery tank and the secondary circuit of which is traversed by the liquid to be heated in the device, prior to its entry into this device by the pipe 18. Thus the liquid which it is desired to heat in the device is it preheated in the exchanger 40 thanks to the still hot liquid from the tank 38 which, after passing through the exchanger 40, arrives at a storage tank 42 from which it is then discharged.

L'utilisation de l'échangeur 40 que l'on vient de décrire permet de réduire la puissance électrique consommée par le générateur de micro-ondes 2 -et donc le coût d'exploitation de l'installation représentée sur la figure 2 pour la même température Ts de sortie du dispositif. A titre d'exemple, la réduction de puissance consommée peut être de l'ordre de 25% pour le chauffage d'eau ultra-pure jusqu'à 80°C.The use of the exchanger 40 which has just been described makes it possible to reduce the electric power consumed by the microwave generator 2 -and therefore the operating cost of the installation shown in FIG. 2 for the same device output temperature Ts. For example, the reduction in power consumed can be of the order of 25% for heating ultra-pure water up to 80 ° C.

Bien entendu, si l'on souhaite chauffer puis utiliser un liquide agressif dans l'installation -par exemple de l'eau pure ou ultra-pure en vue d'un lavage ou d'un rinçage- cette installation doit être conçue pour résister à l'agressivité du liquide en question. En particulier, l'échangeur 16 du magnétron 2 peut être, dans ce cas, un échangeur métallique ayant un revêtement interne constitué par une résine fluorée et l'échangeur de chaleur 40 est par exemple fait d'une matière plastique telle que le PVDF.Of course, if you wish to heat and then use an aggressive liquid in the installation - for example pure or ultra-pure water for washing or rinsing - this installation must be designed to resist the aggressiveness of the liquid in question. In particular, the exchanger 16 of the magnetron 2 can be, in this case, a metal exchanger having an internal coating constituted by a fluorinated resin and the heat exchanger 40 is for example made of a plastic material such as PVDF.

Il faut évidemment que la température du liquide issu du bac 38 soit suffisamment élevée pour obtenir un pré-chauffage non négligeable. A titre d'exemple, si l'on souhaite préchauffer de l'eau pure ou ultra-pure, une température au moins égale à 60°C pour l'eau issue du bac 38 est acceptable.Obviously, the temperature of the liquid coming from the tank 38 must be high enough to obtain a significant preheating. By way of example, if it is desired to preheat pure or ultra-pure water, a temperature at least equal to 60 ° C. for the water coming from tank 38 is acceptable.

Si le liquide à chauffer est trop agressif, l'échangeur 40 est adapté à ce liquide et adjoint au dispositif représenté sur la figure 3, ce qui conduit au dispositif représenté sur la figure 5 : le liquide issu du bac 38 traverse le circuit primaire de l'échangeur 40 puis aboutit au bac de stockage 42 et le liquide agressif que l'on veut préchauffer parcourt le circuit secondaire de l'échangeur 40 puis aboutit à l'entrée du circuit secondaire de l'échangeur 24 (adapté au liquide agressif considéré) par l'intermédiaire de la canalisation 32.If the liquid to be heated is too aggressive, the exchanger 40 is adapted to this liquid and added to the device shown in Figure 3, which leads to the device shown in Figure 5: the liquid from the tank 38 passes through the primary circuit of the exchanger 40 then ends up at the tank storage 42 and the aggressive liquid that is to be preheated travels through the secondary circuit of the exchanger 40 and then leads to the inlet of the secondary circuit of the exchanger 24 (adapted to the aggressive liquid considered) via the pipe 32 .

On notera que le fluide de refroidissement du générateur 2 peut être un gaz, l'air par exemple, lorsque l'échangeur 24 est utilisé (et choisi pour permettre le transfert de chaleur d'un gaz à un liquide).Note that the coolant of the generator 2 can be a gas, air for example, when the exchanger 24 is used (and chosen to allow the transfer of heat from a gas to a liquid).

La présente invention a de nombreuses applications dans des domaines très variés. Elle s'applique notamment à la réalisation de chauffe-eau domestiques ou industriels (secteur de l'électroménager), au réchauffage d'eau ultra pure (secteur de la micro-électronique), au réchauffage d'eau déminéralisée (secteur de la pharmacie, de la médecine), au réchauffage de solution acides agressives (secteur de la chimie) et au réchauffage d'huiles, de liqueurs ou de produits laitiers liquides (secteur de l'agro-alimentaire).The present invention has many applications in a wide variety of fields. It applies in particular to the production of domestic or industrial water heaters (household appliance sector), to the heating of ultra pure water (microelectronics sector), to the heating of demineralized water (pharmacy sector) , medicine), the heating of aggressive acid solutions (chemical sector) and the heating of oils, liqueurs or liquid dairy products (food industry).

Claims (5)

1. Dispositif de chauffage d'un liquide en circulation par des micro-ondes, ce dispositif comprenant :
- un générateur de micro-ondes (2),
- un guide d'ondes (6) destiné à transmettre les micro-ondes produites par le générateur,
- un organe (8) creux et transparent aux micro-­ondes, ayant deux extrémités ouvertes qui forment respectivement une entrée et une sortie dudit organe, le liquide à chauffer étant destiné à circuler de l'entrée à la sortie de l'organe, ce dernier étant couplé électromagnétiquement au générateur par l'intermédiaire du guide d'ondes de sorte que le liquide est chauffé par les micro-ondes lorsqu'il traverse l'organe creux, et
- un échangeur de chaleur (16) qui permet le refroidissement du générateur de micro-ondes par circulation d'un fluide de refroidissement dans cet échangeur,
dispositif caractérisé en ce qu'il comprend en outre des moyens de couplage thermique (16, 22; 24, 34) du générateur (2) à l'organe creux (8), ces moyens de couplage thermique étant prévus pour que le liquide à chauffer y circule et y soit chauffé du fait de la chaleur dégagée par le générateur, avant de circuler dans l'organe creux et d'y être chauffé par les micro-­ondes.1. A device for heating a liquid in circulation by microwaves, this device comprising:
- a microwave generator (2),
- a waveguide (6) intended to transmit the microwaves produced by the generator,
- a member (8) hollow and transparent to microwaves, having two open ends which respectively form an inlet and an outlet of said member, the liquid to be heated being intended to circulate from the inlet to the outlet of the member, this the latter being electromagnetically coupled to the generator via the waveguide so that the liquid is heated by microwaves when it passes through the hollow member, and
- a heat exchanger (16) which allows the cooling of the microwave generator by circulation of a cooling fluid in this exchanger,
device characterized in that it further comprises thermal coupling means (16, 22; 24, 34) of the generator (2) to the hollow member (8), these thermal coupling means being provided so that the liquid to heating circulates there and is heated there because of the heat given off by the generator, before circulating in the hollow organ and being heated there by microwaves. 2. Dispositif selon la revendication 1, caractérisé en ce que les moyens de couplage thermique comprennent ledit échangeur de chaleur (16) et une canalisation (22) reliant la sortie de celui-ci à l'entrée de l'organe creux, le liquide à chauffer étant destiné à circuler de l'entrée dudit échangeur de chaleur (16) à la sortie de l'organe creux (8) et servant donc aussi de fluide de refroidissement du générateur.2. Device according to claim 1, characterized in that the thermal coupling means comprise said heat exchanger (16) and a pipe (22) connecting the outlet thereof to the inlet of the hollow member, the liquid to be heated being intended to circulate from the inlet of said heat exchanger heat (16) at the outlet of the hollow member (8) and therefore also serving as the generator coolant. 3. Dispositif selon la revendication 1, caractérisé en ce que les moyens de couplage thermique comprennent un autre échangeur de chaleur (24) comportant :
- un circuit primaire (25) dont l'entrée est reliée à la sortie de l'échangeur de chaleur (16) permettant le refroidissement du générateur de micro-­ondes (2), et qui est donc destiné à être traversé par le fluide de refroidissement, ce dernier étant chauffé par passage dans l'échangeur de chaleur (16) permettant le refroidissement du générateur de micro-ondes, et
- un circuit secondaire (30) qui est couplé thermiquement au circuit primaire (25) et dont la sortie est reliée à l'entrée de l'organe creux (8) par une canalisation (34), le liquide à chauffer étant destiné à circuler de l'entrée du circuit secondaire (30) à la sortie de l'organe creux (8).3. Device according to claim 1, characterized in that the thermal coupling means comprise another heat exchanger (24) comprising:
- a primary circuit (25) whose input is connected to the output of the heat exchanger (16) allowing the cooling of the microwave generator (2), and which is therefore intended to be traversed by the cooling, the latter being heated by passage through the heat exchanger (16) allowing the cooling of the microwave generator, and
- a secondary circuit (30) which is thermally coupled to the primary circuit (25) and the outlet of which is connected to the inlet of the hollow member (8) by a pipe (34), the liquid to be heated being intended to circulate from the input of the secondary circuit (30) to the output of the hollow member (8). 4. Dispositif selon la revendication 3, caractérisé en ce que le circuit secondaire (30) dudit autre échangeur de chaleur (24) et la canalisation (34) reliant ce circuit secondaire à l'organe creux (8) sont conçus pour la circulation d'un liquide corrosif.4. Device according to claim 3, characterized in that the secondary circuit (30) of said other heat exchanger (24) and the pipe (34) connecting this secondary circuit to the hollow member (8) are designed for circulation d '' a corrosive liquid. 5. Dispositif selon l'une quelconque des revendications 1 à 4, caractérisé en ce qu'il comprend en outre un échangeur (40) prévu pour récupérer de la chaleur du liquide chauffé dans le dispositif, après utilisation de ce liquide, et pour chauffer, avec cette chaleur, ce même liquide avant son entrée dans le dispositif.5. Device according to any one of claims 1 to 4, characterized in that it further comprises an exchanger (40) provided for recovering heat from the liquid heated in the device, after use of this liquid, and for heating , with this heat, this same liquid before entering the device.
EP89401976A 1988-07-11 1989-07-10 Microwave heating device for a flowing fluid Withdrawn EP0351300A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8809395 1988-07-11
FR8809395A FR2634091A1 (en) 1988-07-11 1988-07-11 DEVICE FOR HEATING A LIQUID IN CIRCULATION BY MICROWAVES

Publications (1)

Publication Number Publication Date
EP0351300A1 true EP0351300A1 (en) 1990-01-17

Family

ID=9368319

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89401976A Withdrawn EP0351300A1 (en) 1988-07-11 1989-07-10 Microwave heating device for a flowing fluid

Country Status (2)

Country Link
EP (1) EP0351300A1 (en)
FR (1) FR2634091A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997005756A1 (en) * 1995-07-26 1997-02-13 Ramot University Authority For Applied Research & Industrial Development Ltd. Liquid heating in interaction region of microwave generator
EP0765105A2 (en) * 1995-09-22 1997-03-26 Eastman Kodak Company Microwave heating apparatus
DE19746437A1 (en) * 1997-10-21 1999-04-29 Ralf Isenberg Production of beer-brewing wort comprises using pulse frequency modulated microwave heating source powered by block-type thermal power station for rapid heating
EP1176370A2 (en) * 2000-07-28 2002-01-30 Masakazu Matuo Continuous flow type heating apparatus
US7109453B1 (en) 2005-02-01 2006-09-19 Keith A Nadolski Microwave hot water system

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4065361A (en) * 1976-09-10 1977-12-27 Lester Hanson Apparatus and system for processing oil shale
DE2731513A1 (en) * 1976-07-12 1978-01-19 Int Microwave Corp MICROWAVE HEATING DEVICE AS WELL AS HEATING SYSTEM AND ROOM HEATING METHOD USING THIS
US4358652A (en) * 1978-12-21 1982-11-09 Kaarup Darrell R Fluid heater apparatus
DE3139268A1 (en) * 1981-10-02 1983-04-21 geb. Görts Ingrid Drübenbach Device operated at very high frequencies for heating liquids
US4417116A (en) * 1981-09-02 1983-11-22 Black Jerimiah B Microwave water heating method and apparatus
DE3428514A1 (en) * 1984-08-02 1986-03-06 Lübke, Manfred, 4722 Ennigerloh Heating fluids by means of superhigh-frequency radiation for the purpose of utilisation as a heating installation
DE3639717A1 (en) * 1986-11-20 1988-06-01 Ludwig Juergen Zeffner Device for generating water vapour

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2731513A1 (en) * 1976-07-12 1978-01-19 Int Microwave Corp MICROWAVE HEATING DEVICE AS WELL AS HEATING SYSTEM AND ROOM HEATING METHOD USING THIS
US4065361A (en) * 1976-09-10 1977-12-27 Lester Hanson Apparatus and system for processing oil shale
US4358652A (en) * 1978-12-21 1982-11-09 Kaarup Darrell R Fluid heater apparatus
US4417116A (en) * 1981-09-02 1983-11-22 Black Jerimiah B Microwave water heating method and apparatus
DE3139268A1 (en) * 1981-10-02 1983-04-21 geb. Görts Ingrid Drübenbach Device operated at very high frequencies for heating liquids
DE3428514A1 (en) * 1984-08-02 1986-03-06 Lübke, Manfred, 4722 Ennigerloh Heating fluids by means of superhigh-frequency radiation for the purpose of utilisation as a heating installation
DE3639717A1 (en) * 1986-11-20 1988-06-01 Ludwig Juergen Zeffner Device for generating water vapour

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997005756A1 (en) * 1995-07-26 1997-02-13 Ramot University Authority For Applied Research & Industrial Development Ltd. Liquid heating in interaction region of microwave generator
US5998773A (en) * 1995-07-26 1999-12-07 Ramot University Authority For Applied Research & Industrial Development Ltd. Liquid heating in interaction region of microwave generator
EP0765105A2 (en) * 1995-09-22 1997-03-26 Eastman Kodak Company Microwave heating apparatus
EP0765105A3 (en) * 1995-09-22 1997-10-22 Eastman Kodak Co Microwave heating apparatus
DE19746437A1 (en) * 1997-10-21 1999-04-29 Ralf Isenberg Production of beer-brewing wort comprises using pulse frequency modulated microwave heating source powered by block-type thermal power station for rapid heating
DE19746437B4 (en) * 1997-10-21 2004-11-18 Hrch. Huppmann Gmbh Method and device for heating mash and / or wort
EP1176370A2 (en) * 2000-07-28 2002-01-30 Masakazu Matuo Continuous flow type heating apparatus
EP1176370A3 (en) * 2000-07-28 2003-09-10 Masakazu Matuo Continuous flow type heating apparatus
US7109453B1 (en) 2005-02-01 2006-09-19 Keith A Nadolski Microwave hot water system

Also Published As

Publication number Publication date
FR2634091A1 (en) 1990-01-12

Similar Documents

Publication Publication Date Title
EP1945074B1 (en) Device for heating fluid in a household appliance
EP2883006B1 (en) Device for the induction heating of a water heater and water heater provided with such a device
FR2625794A1 (en) WATER VAPOR GENERATOR FOR COOKING APPLIANCE
EP0476311B1 (en) Electrif fluid heater
EP0351300A1 (en) Microwave heating device for a flowing fluid
EP3030845A1 (en) Water heater
CN108518851A (en) A kind of induction heating apparatus of high efficient and reliable
CA2055975C (en) Induction heating molecular distillation apparatus and process for manufacturing components therefor
FR2644313A1 (en) DEVICE FOR ELECTRICALLY HEATING BY INDUCTION OF A FLUID CONTAINED IN A PIPELINE
CA2444537A1 (en) Electric water heater, liquid heater, steam generator
EP0086730A1 (en) Microwave boiler for the production of a heated fluid for domestic or industriel use or for room heating, and process used by this boiler
BE1000469A7 (en) Generator thermal fluid hot induction.
FR2551998A1 (en) DEVICE FOR BENDING TUBES OR SIMILAR ARTICLES
FR3001285A1 (en) Electric boiler for water storage and heating installation, has water circulation blocks including two sets of internal water circulation channels to form two independent internal water circuits, respectively
FR2669470A1 (en) METHOD OF COOLING A CURRENT MECHANISM FOR VERY LOW TEMPERATURE ELECTRICAL EQUIPMENT AND DEVICE FOR ITS IMPLEMENTATION.
WO2016046171A1 (en) Device for thermal processing of a fluid, having reduced energy consumption
EP0082095A1 (en) Arrangement for heating and/or stirring and/or transferring metals in the liquid state
FR2501631A1 (en) Sterilising canned food prods. passing continuously through tube - with heat supplied entirely by electrical induction and resistance elements
EP3477211B1 (en) Device for heating a fluid flowing in a pipe and thermal installation comprising such a device
FR2818085A1 (en) Heating installation esp for viscous products comprises insulated pipe divided into sections by rotary disc electrodes linked to power supply
WO2017108579A1 (en) Hot-water storage multi-tank domestic water heater
FR2565059A1 (en) Device for heating a fluid by induction
BE408814A (en)
EP2306114A1 (en) Heater
JP2000058241A (en) Heating device

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE GB NL

17P Request for examination filed

Effective date: 19900623

17Q First examination report despatched

Effective date: 19920921

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19930202