WO2020183344A1 - Device for heating liquids - Google Patents

Device for heating liquids Download PDF

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Publication number
WO2020183344A1
WO2020183344A1 PCT/IB2020/052023 IB2020052023W WO2020183344A1 WO 2020183344 A1 WO2020183344 A1 WO 2020183344A1 IB 2020052023 W IB2020052023 W IB 2020052023W WO 2020183344 A1 WO2020183344 A1 WO 2020183344A1
Authority
WO
WIPO (PCT)
Prior art keywords
coil
hollow body
heating device
heating
liquid
Prior art date
Application number
PCT/IB2020/052023
Other languages
French (fr)
Inventor
Matteo SPOLDI
Original Assignee
Lauma Elettronica S.R.L.
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 Lauma Elettronica S.R.L. filed Critical Lauma Elettronica S.R.L.
Priority to CH00485/21A priority Critical patent/CH716873B1/en
Priority to EP20713102.0A priority patent/EP3935917A1/en
Publication of WO2020183344A1 publication Critical patent/WO2020183344A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
    • F24H1/12—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium
    • F24H1/14—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form
    • F24H1/142—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form using electric energy supply
    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
    • A47J31/00—Apparatus for making beverages
    • A47J31/44—Parts or details or accessories of beverage-making apparatus
    • A47J31/54—Water boiling vessels in beverage making machines
    • A47J31/542—Continuous-flow heaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
    • F24H1/12—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium
    • F24H1/14—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form
    • F24H1/16—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form helically or spirally coiled
    • F24H1/162—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium by tubes, e.g. bent in serpentine form helically or spirally coiled using electrical energy supply
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/18—Arrangement or mounting of grates or heating means
    • F24H9/1809—Arrangement or mounting of grates or heating means for water heaters
    • F24H9/1818—Arrangement or mounting of electric heating means
    • 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
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
    • H05B6/108—Induction heating apparatus, other than furnaces, for specific applications using a susceptor for heating a fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H2250/00—Electrical heat generating means
    • F24H2250/08—Induction

Definitions

  • the present invention relates to a device for heating liquids, particularly but not exclusively useful and practical in the operations for heating water, milk or oils to be used in the civil or industrial field for countless purposes, for example for domestic heating (i.e., warm running water).
  • An electric boiler must in fact be always on and operating in order to ensure that the liquid inside it reaches a temperature - typically set by the user that is constant over time.
  • a gas boiler must heat a quantity of liquid that is greater than the quantity required by the user in order to ensure dispensing of the liquid at a temperature that is constant over time.
  • these boilers are fueled with methane gas and perform their task by burning this gas and therefore have risks both of leaks of methane gas or carbon monoxide and of accidents due to the high flammability of the methane gas itself.
  • EP2868242A1 describes a device for heating water in a machine for preparing and dispensing beverages, constituted substantially by a hollow spool, an electromagnetic induction winding arranged around the hollow spool, and a duct accommodated inside the hollow spool and crossed internally by a stream of water.
  • the aim of the present invention is to overcome the limitations of the background art described above, by providing a device for heating liquids that allows to obtain better effects than those obtainable with known solutions and/or similar effects at a lower cost and with higher performance.
  • an object of the present invention is to provide a device for heating liquids that allows to heat a liquid from any initial temperature to a chosen final temperature, up to the gaseous state.
  • a further object of the present invention is to provide a device for heating liquids that ensures high safety, particularly for the subject—whether an ordinary user or a specialized technician— who handles the device, for example during installation or any operations for maintenance of said device, or during any operations for the maintenance of the machine or of the apparatus in which said device is installed.
  • Another object of the present invention is to provide a device for heating liquids that allows to obtain an energy saving with respect to the background art.
  • a further object of the present invention is to provide a device for heating liquids that does not need to be constantly active in order to be able to heat the liquid in an adequate manner.
  • Another object of the present invention is to provide a device for heating liquids that allows the heating of a quantity of liquid that is substantially limited to the actual requirement of the user.
  • a further object of the present invention is to provide a device for heating liquids that allows to avoid using a gas boiler—typically a methane boiler— consequently reducing the risks that derive from the use of this extremely flammable gas.
  • an object of the present invention is to provide a device for heating liquids that allows to also avoid using an electric boiler.
  • Another object of the present invention is to provide a device for heating liquids that has reduced dimensions, thus reducing the space occupation.
  • Another object of the present invention is to provide a device for heating liquids that is highly reliable, relatively simple to provide and install, and economically competitive if compared with the background art.
  • a device for heating liquids comprising at least one longitudinally extended hollow body, an electrical winding arranged around said hollow body and made of electrically conducting metallic material, and a longitudinally extended coil which passes inside said hollow body and is crossed internally by a stream of liquid and comprises electrically conducting metallic material, said electrical winding being configured to generate an electromagnetic field adapted to induce an electrical current in said coil for the electromagnetic induction heating of said coil, said coil being in thermal contact with said stream of liquid;
  • said hollow body comprises a first end and a second end, the cavity of said hollow body comprising a first opening arranged at said first end and a second opening arranged at said second end;
  • said first opening of said cavity of said hollow body is at least partially occluded by a first closure plate
  • said second opening of said cavity of said hollow body is at least partially occluded by a second closure plate, said coil being enclosed within said hollow body by means of said first and second closure plates.
  • Figure 1 is a perspective view of an embodiment of the device for heating liquids according to the present invention
  • Figures 2a and 2b are a perspective view and a sectional view, taken along a vertical plane, of a first variation of an embodiment of the device for heating liquids, according to the present invention
  • Figures 3a and 3b are a perspective view and a sectional view, taken along a vertical plane, of a second variation of an embodiment of the device for heating liquids according to the present invention
  • Figures 4a and 4b are a perspective view and a sectional view, taken along a vertical plane, of a third variation of an embodiment of the device for heating liquids according to the present invention.
  • Figure 5 is a top plan view of an embodiment of the device for heating liquids according to the present invention.
  • the device for heating liquids substantially comprises at least one longitudinally extended hollow body 12, an electrical winding 18 arranged around the hollow body 12, in particular around the outer wall of the latter, and a longitudinally extended coil 20 which passes within the hollow body 12, in particular through the cavity of the hollow body 12.
  • the cavity of the hollow body 12 also is extended longitudinally.
  • the hollow body 12 is the supporting element of the heating device 10 and comprises a first end 14 and a second end 16.
  • the cavity of the hollow body 12 comprises a first opening, arranged at the first end 14, and a second opening, arranged at the second end 16.
  • the cavity of the hollow body 12 is delimited by the internal wall of the latter.
  • the first opening of the cavity of the hollow body 12 is occluded partially or completely by a first closure plate 25, which is arranged and fixed at the first end 14.
  • the second opening of the cavity of the hollow body 12 is partially or completely occluded by a second closure plate (not shown), which is arranged and fixed at the second end 16.
  • first closure plate 25 and the second closure plate can be fixed to the first end 14 and to the second end 16 of the hollow body 12, respectively, by virtue of interlocking couplings or fastened by means of threaded grubs.
  • the coil 20 is substantially enclosed within the hollow body 12 by means of the closure plates cited above, constituting a single body.
  • the end portions of the coil 20, in particular an inlet portion and an outlet portion, can protrude from the hollow body 12 and therefore from the single body.
  • the substantially complete closure of the coil 20 within the hollow body 12 by means of the closure plates ensures both a correct and safe operation of the device 10 according to the invention, particularly according to the operating specifications, and a correct and safe installation of said device 10 in a machine or an apparatus, without leaving room for any errors during installation.
  • the coil 20 comprises preferably ferromagnetic electrically conducting metallic material, said coil 20 would alter the total inductance value if it were not completely enclosed within the hollow body 12.
  • Said coil 20 in fact has a magnetic coupling with the electrical winding 18 arranged around the hollow body 12.
  • the device 10 according to the invention is configured so that the coil 20 and the electrical winding 18 of the hollow body 12 operate within certain limits or ranges of magnetic coupling. If this magnetic coupling between the coil 20 and the electrical winding 18 were not within the limits or ranges cited above, the device 10 according to the invention would run the risk of malfunctioning.
  • the absorptions from the electrical power mains would be up to two and a half times higher than those actually required during normal operation.
  • a condition of normal operation of the device 10 according to the invention for a given application may have an absorption from the electric power mains of 1 kW; if the coil 20 were enclosed for two thirds of its length in the hollow body 12, the absorption from the electrical power mains would be greater than 2.3 kW and would lead to the failure of the electronic power board 30.
  • the fact that the hollow body 12 and the coil 20 are substantially part of a single body speeds up the installation of the device 10 according to the invention on the part of the operator, who simply has to connect the two ends of the device 10, for example by means of the intake manifold 24 and the discharge manifold 26, and the electrical connections 32.
  • Another advantage of the monolithic solution, comprising the hollow body 12, the coil 20, the first closure plate 25 and the second closure plate, consists in that the cavity of the hollow body 12 in which the coil 20 heated by electromagnetic induction is arranged is not accessible during the operation of the device 10 according to the invention.
  • the hollow body 12 can have any geometry, any cross-section and any length, to be defined in each instance according to the requirements of the case.
  • the hollow body 12 has a circular cross-section. Accordingly, both the external wall of the hollow body 12 and the internal wall of the hollow body 12 have a circular cross-section.
  • the hollow body 12 has a tubular shape, i.e. it is a cylindrical hollow body of variable length. In other embodiments, which are different from the preferred and illustrated ones, the hollow body 12 is frustum- shaped.
  • the hollow body 12 has a simple, preferably regular, polygonal cross-section, such as for example a square cross-section, a rectangular cross-section, a hexagonal cross-section, and so forth.
  • the hollow body 12 can be made of any heat-resistant material, such as for example a plastic material (for example polyamide 66).
  • a plastic material for example polyamide 66
  • the hollow body 12 is made of an electrically insulating material.
  • the electrical winding 18 of the heating device 10, which as mentioned is arranged around the hollow body 12, is made of electrically conducting metallic material, for example, copper or aluminum of the multistranded or solid-core type.
  • the electrical winding 18 is arranged in contact with the external wall of the hollow body 12.
  • the electrical winding 18 is arranged proximate to the external wall of the hollow body 12.
  • the electrical winding 18 has a cylindrical helical shape, with a pitch that can vary according to the requirements of the case.
  • the electrical winding 18 is covered externally by an insulating layer 22.
  • the insulating layer 22 is made of any electrically and thermally insulating material, for example an epoxy resin, a silicone resin, or a thermoplastic resin.
  • the insulating layer 22 is made of a thermoplastic resin, such as for example polyethylene terephthalate (e.g. Mylar®).
  • the electrical winding 18 is configured to transfer the energy required for the electromagnetic induction heating of the coil 20.
  • the electrical winding 18 is configured to generate an electromagnetic field that is suitable to induce an electrical current in the coil 20 for the electromagnetic induction heating of said coil 20.
  • the electrical winding 18 acts as an inductor or a coil.
  • electromagnetic induction heating is a method that has been developed to heat electrically conducting materials, in particular ferromagnetic materials. Electromagnetic induction heating entails that the alternating electrical current flows across the electrical winding 18, which, by generating an electromagnetic field, induces the same alternating electrical current to the coil 20, heating the latter. This physical process is known as an electromagnetic induction or Faraday’s law.
  • the coil 20 After being heated by electromagnetic induction, the coil 20 transfers heat toward the stream of liquid that flows inside it, in particular by means of the contact between the coil 20 and the liquid.
  • the alternating electrical current induced in the coil 20 heats it to a desired temperature, so that the stream of liquid that flows within the coil 20 is in turn heated.
  • the heating device 10 furthermore comprises at least one electronic power board 30 which is connected to the electrical winding 18, in particular to its ends, by means of electrical cables 32, for example of the multistranded or solid-core type.
  • the electrical connections 32 from the electronic power board 30 to the electrical winding 18 have a length that is less than or equal to one meter. Obviously, it is possible to also use electrical connections 32 longer than one meter, but in this case there is a considerable decrease in the delivered power.
  • the electronic power board 30 is powered by the electric power distribution mains.
  • the electronic power board 30 is configured to supply the electrical winding 18 with the alternating current required to generate the electromagnetic field for the electromagnetic induction heating of the coil 20.
  • the electronic power board 30 operates like a radiofrequency electric current generator.
  • the operating frequency value or range of the electronic power board 30 depends exclusively on the desired temperature, on the quantity of liquid to be heated that flows within the coil 20, and on the heating coefficient of the liquid being considered.
  • the coil 20 of the heating device 10 which as mentioned passes within the hollow body 12, is a tube or duct that is crossed internally by the stream of liquid to be heated.
  • the coil 20 is made of a preferably ferromagnetic electrically conducting metallic material.
  • the coil 20 is made of silicone material, i.e., silicone- based material, covered by a braid made of electrically conducting, preferably ferromagnetic, metallic material. This combination of silicone material and metallic braid allows an easier construction of the coil 20 and extends the possibilities of use of the device 10 according to the invention, for example in the food sector.
  • the coil 20 is in thermal contact with the stream of liquid.
  • the coil 20 is configured to transfer heat toward the stream of liquid that flows inside it.
  • the stream of liquid that exits from the coil 20 can reach any temperature, up to the gaseous state.
  • the coil 20 is configured to contain the stream of liquid to be heated and to guide its flow from an inlet portion of said coil 20, located for example proximate to the first end 14 of the hollow body 12 and/or proximate to the first opening of the cavity of the hollow body 12, to an outlet portion of said coil 20, for example arranged proximate to the second end 16 of the hollow body 12 and/or proximate to the second opening of the cavity of the hollow body 12.
  • the coil 20 can have any geometry, any cross-section and any length, to be defined in each instance depending on the requirements of the case.
  • the coil 20 has a circular cross- section.
  • the coil 20 has a helical, preferably cylindrical shape, with a pitch that can vary according to the requirements of the case.
  • the coil 20 has a helical shape, preferably a cylindrical shape, and at least one part of its turns, preferably all of them, is arranged in contact with the internal wall of the hollow body 12.
  • the coil 20 has a helical, preferably cylindrical shape, and at least one part of its turns, preferably all, is associated with the hollow body 12.
  • the coil 20 and the hollow body 12 are associated monolithically.
  • the coil 20 has a helical, preferably cylindrical shape and at least one part of its turns, preferably all, are arranged proximate to the internal wall of the hollow body 12.
  • the coil 20 is parallel to the central longitudinal axis of the hollow body 12 and preferably coincides therewith.
  • the shape and/or size of some components of the heating device 10 according to the invention depend exclusively on the desired temperature, on the quantity of liquid to be heated that flows within the coil 20, and on the heating coefficient of the liquid being considered.
  • the heating device 10 furthermore comprises an intake manifold 24 and a discharge manifold 26 which are configured to connect the coil 20 to a system of ducts for the flow of the liquid.
  • the intake manifold 24 is connected to the inlet of the coil 20, for example arranged proximate to the first end 14 of the hollow body 12 and/or proximate to the first opening of the cavity of the hollow body 12.
  • the discharge manifold 26 is connected to the output of the coil 20, for example arranged proximate to the second end 16 of the hollow body 12 and/or proximate to the second opening of the cavity of the hollow body 12.
  • the intake manifold 24 is coupled to the first closure plate 25, which as mentioned is arranged at the first end 14 of the hollow body 12, and the discharge manifold 26 is coupled to the second closure plate, which as mentioned is arranged at the second end 16 of the hollow body 12.
  • the heating device 10 furthermore comprises an electric valve 28 of the three-way type, which is configured to load and discharge the liquid in the coil 20.
  • the electric valve 28 is associated with the discharge manifold 26.
  • the electric valve 28 is configured to load the heat liquid to be heated into the hydraulic circuit, in particular into the coil 20, before the operations for heating (and subsequent dispensing), i.e. before the electromagnetic induction heating of said coil 20.
  • the flow of the stream of liquid in the coil 20 can occur by gravity or by means of a pump or by means of the pressure of a water system.
  • the electric valve 28 opens the circulation of the liquid inside the coil 20 before the device 10 according to the invention is on.
  • the device 10 according to the invention can start the heating operations. This is useful to avoid the "dry” operation of the device 10, i.e. without flow of the stream of liquid inside it, in particular in the coil 20.
  • the "dry" operation of the device 10 can in fact lead to very high temperatures in a few seconds and to the consequent damage of said device 10.
  • the electric valve 28 is configured to discharge the residual liquid that is present within the hydraulic circuit, in particular in the coil 20, after the operations for heating (and subsequent dispensing), i.e., after the electromagnetic induction heating of said coil 20.
  • the electric valve 28 does not leave liquid inside the coil 20 after the device 10 according to the invention has been turned off.
  • This discharge operation performed by the electric valve 28 is useful to prevent the liquid from stagnating within the hydraulic circuit, in particular in the coil 20, and said liquid from freezing in the case of low temperatures.
  • the three-way electric valve 28 can be replaced by an electric loading valve, preferably associated with the intake manifold 24, and an electric discharge valve, preferably associated with the discharge manifold 26.
  • the device 10 for heating liquids according to the invention comprises a plurality of hollow bodies 12 which are mutually connected in series, in a number that can vary according to the requirements of the case, where the coil 20 passes within the plurality of hollow bodies 12.
  • the hollow bodies 12 of said plurality all have the same cross-section.
  • the heating device 10 is controlled and operated by one or more electronic boards (including the electronic power board 30) which can have different configurations of the hardware and/or software type, to be defined in each instance according to the requirements of the case, for example on the basis of the length of the hollow body 12 and of the coil 20, or on the basis of the desired temperature that the liquid must reach in output from the coil 20.
  • electronic boards including the electronic power board 30
  • the electronic power board 30 can have different configurations of the hardware and/or software type, to be defined in each instance according to the requirements of the case, for example on the basis of the length of the hollow body 12 and of the coil 20, or on the basis of the desired temperature that the liquid must reach in output from the coil 20.
  • the adjustment of the temperature of the liquid in output from the coil 20 occurs by means of an appropriate hardware and/or software configuration of the electronic boards cited above. For example, by means of these configurations it is possible to set different temperature thresholds of the liquid in output from the coil 20.
  • the heating device 10 furthermore comprises a thermistor which is arranged in thermal contact with the coil 20, preferably with an end portion of the coil 20, and is functionally connected to a control unit of the heating device 10 according to the invention, and optionally also to the electronic power board 30.
  • the thermistor can be in contact with the external wall or the internal wall of the coil 20.
  • the thermistor can be arranged at any one of the closure plates of the openings of the cavity of the hollow body 12.
  • the thermistor is characterized according to the temperature detected on the coil 20.
  • the thermistor is sensitive to the temperature of the coil 20.
  • the thermistor is configured to detect the temperature of the coil 20 and to report the temperature detected on the coil 20 to the control unit, for example by means of an adapted circuit.
  • control unit is configured to calculate the temperature of the stream of liquid that flows inside the coil 20 on the basis of the temperature detected by the thermistor on the coil 20 by means of an appropriate algorithm.
  • the control unit is furthermore configured to control the electronic power board 30 and vary the operating frequency of said electronic power board 30 on the basis of the power required to reach the desired temperature of the liquid with respect to the actual temperature calculated beforehand by the control unit.
  • the heating device 10 furthermore comprises a thermistor which is arranged in thermal contact with the stream of liquid that flows inside the coil 20 and is functionally connected to the control unit of the heating device 10 according to the invention and optionally also to the electronic power board 30.
  • the thermistor can be arranged at any one of the closure plates of the openings of the cavity of the hollow body 12.
  • the thermistor is characterized on the basis of the temperature detected on the stream of liquid.
  • the thermistor is sensitive to the temperature of the stream of liquid.
  • the thermistor is configured to detect the temperature of the stream of liquid that flows inside the coil 20 and to report to the temperature detected on the stream of liquid to the control unit, for example by means of an appropriate circuit.
  • control unit is configured to control the electronic power board 30 and vary the operating frequency of said electronic power board 30 on the basis of the power required to reach the desired temperature of the liquid with respect to the actual temperature detected previously by the thermistor.
  • the thermistor of the heating device 10 according to the invention is of the NTC type (from the English Negative Temperature Coefficient), in practice with a resistance that decreases as the temperature increases.
  • the adjustment of the temperature of the liquid has a precision of less than 0.5°C and allows minimum use of the electric power absorbed by the device 10 according to the invention to heat the liquid inside it.
  • control unit of the heating device 10 by interacting with the thermistor arranged in thermal contact with the coil 20, is capable of adjusting the minimum power of the electromagnetic induction that is needed to bring the liquid to desired temperature or keep it thereat.
  • the control unit of the heating device 10 allows to consume only the quantity of liquid and power that are strictly necessary by means of the adjustment of the temperature of the liquid and the management of the electric valve 28.
  • the heating device 10 furthermore comprises a safety device 45 which is arranged in thermal contact with the coil 20, preferably with an end portion of the coil 20, and is functionally connected to the electronic power board 30.
  • the safety device 45 can be in contact with the external wall or the internal wall of the coil 20.
  • the safety device 45 can be arranged at any one of the closure plates of the openings of the cavity of the hollow body 12.
  • the safety device 45 is sensitive to the temperature of the coil 20.
  • the safety device 45 is configured to detect the temperature of the coil 20 and to trip if the temperature of the coil 20 exceeds a threshold value.
  • the safety device 45 is configured to stop the electromagnetic induction heating of the coil 20, interrupting the electric power supply of the electronic power board 30, if a threshold temperature (preset for example to 120°C) is exceeded on the coil 20.
  • a threshold temperature preset for example to 120°C
  • the safety device 45 is configured to stop the heating device 10 according to the invention if its coil 20 reaches a temperature that exceeds the threshold value (for example 120°C).
  • the safety device 45 trips, opening the circuit, therefore acting as a breaker, and interrupting the electric power supply of the electronic power board 30.
  • the heating device 10 according to the invention must cool down and be turned on again. The heating device 10 restarts when the temperature of the coil 20 returns below the threshold value.
  • the safety device 45 of the heating device 10 comprises a metallic flange which is arranged in thermal contact with the coil 20 and a temperature regulator which is associated with the flange and is functionally connected to the electronic power board 30.
  • the temperature regulator comprises a resettable thermal safety (for example, a thermal safety which can be reset at 120°C), which is also metallic and associated with the flange for example by screwing.
  • the safety device 45 allows, in the case of malfunction, if any, to stop the heating device 10 according to the invention and prevent the coil 20 from melting the hollow body 12 or, worse still, causing a fire of the components. In any fault situation, the safety device 45 allows the temperature of the coil 20 to remain under control, allows the electronic power board 30 not to be damaged, and allows the operating temperature of the coil 20, and therefore of the heating device 10, to remain within the safety limits provided by the applicable statutory provisions and by the technical specifications of the materials used.
  • the heating device 10 is included in a box-shaped body 50 which is adapted to protect the various components, in particular the hollow body 12, the electrical winding 18 and the electronic power board 30.
  • the liquid to be heated enters the coil 20 of the heating device 10 through, in the following order: an intake port 36, an intake duct 34 and the intake manifold 24.
  • the heated liquid exits from the coil 20 of the heating device 10 through, in the following order: the discharge manifold 26, a discharge duct 38 and an outlet port 40.
  • the liquid to be heated to the desired temperature enters the coil 20 of the heating device 10, which as mentioned passes within the hollow body 12.
  • the electrical winding 18 of the heating device 10 which as mentioned is arranged around the hollow body 12, generates an electromagnetic field that is adapted to induce an electrical current for the electromagnetic induction heating of said coil 20.
  • the coil 20 then transfers heat toward the stream of liquid that flows inside it, in particular by means of the thermal contact between the coil 20 and the liquid.
  • the liquid heated to the desired temperature exits from the coil 20 of the heating device 10.
  • the device for heating liquids thus conceived allows to overcome the quality limitations of the background art, since it allows to achieve better effects than those obtainable with known solutions and/or similar effects at lower cost and with a higher performance.
  • One advantage of the device for heating liquids according to the present invention resides in that it allows to heat a liquid from any initial temperature to a desired final temperature, up to the gaseous state, during the travel time inside the coil.
  • a further advantage of the device for heating liquids according to the present invention resides in that it ensures high safety, in particular for the subject—whether an ordinary user or a specialized technician— who handles the device, for example during installation or during any operations for the maintenance of said device, or during any operations for maintenance of the machine or of the apparatus in which said device is installed.
  • Another advantage of the device for heating liquids according to the present invention resides in that it allows to obtain a high energy saving with respect to the background art.
  • a further advantage of the device for heating liquids according to the present invention resides in that it does not need to be constantly active in order to be able to heat the liquid adequately.
  • Another advantage of the device for heating liquids according to the present invention resides in that it allows the heating of a quantity of liquid that is substantially limited to the strict amount necessary.
  • a further advantage of the device for heating liquids according to the present invention resides in that it allows to avoid having a gas boiler—typically a methane boiler— consequently reducing the risks that arise from the use of this extremely flammable gas.
  • an advantage of the device for heating liquids according to the present invention resides in that it allows to avoid having an electric boiler as well.
  • Another advantage of the device for heating liquids according to the present invention resides in that it has reduced dimensions, thus reducing the space occupation considerably.
  • the device for heating liquids according to the invention has been conceived in particular for operations for heating water, milk or oils to be used in the civil or industrial field for countless purposes, for example for domestic heating (i.e., warm running water), it can in any case be used more generally to heat any type of liquid or to produce steam.
  • the materials used may be any according to the requirements and the state of the art.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Food Science & Technology (AREA)
  • General Induction Heating (AREA)
  • Beverage Vending Machines With Cups, And Gas Or Electricity Vending Machines (AREA)

Abstract

A device (10) for heating liquids, comprising at least one longitudinally extended hollow body (12), an electrical winding (18) arranged around the hollow body (12), and a longitudinally extended coil (20) which passes inside the hollow body (12) and is crossed internally by a stream of liquid, the electrical winding (18) being configured to generate an electromagnetic field adapted to induce an electrical current in the coil (20) for the electromagnetic induction heating of the coil (20), the coil (20) being in thermal contact with the stream of liquid; the hollow body (12) comprises a first end (14) and a second end (16), the cavity of the hollow body (12) comprising a first opening arranged at the first end (14) and a second opening arranged at the second end (16); and the first opening of the cavity of the hollow body (12) is at least partially occluded by a first closure plate (25), and the second opening of the cavity of the hollow body (12) is at least partially occluded by a second closure plate, the coil (20) being enclosed within the hollow body (12) by means of the first and second closure plates.

Description

DEVICE FOR HEATING LIQUIDS
The present invention relates to a device for heating liquids, particularly but not exclusively useful and practical in the operations for heating water, milk or oils to be used in the civil or industrial field for countless purposes, for example for domestic heating (i.e., warm running water).
Currently it is known to use electric boilers or gas boilers - typically methane boilers -specifically adapted to the heating of liquids, mainly water but also other substances.
However, these known solutions are not free from drawbacks, such as the fact that they have a very high energy dispersion, consequently being highly inefficient from the energy and operational standpoint.
An electric boiler must in fact be always on and operating in order to ensure that the liquid inside it reaches a temperature - typically set by the user that is constant over time.
Likewise, a gas boiler must heat a quantity of liquid that is greater than the quantity required by the user in order to ensure dispensing of the liquid at a temperature that is constant over time.
Furthermore, as mentioned above, these boilers are fueled with methane gas and perform their task by burning this gas and therefore have risks both of leaks of methane gas or carbon monoxide and of accidents due to the high flammability of the methane gas itself.
EP2868242A1 describes a device for heating water in a machine for preparing and dispensing beverages, constituted substantially by a hollow spool, an electromagnetic induction winding arranged around the hollow spool, and a duct accommodated inside the hollow spool and crossed internally by a stream of water.
The aim of the present invention is to overcome the limitations of the background art described above, by providing a device for heating liquids that allows to obtain better effects than those obtainable with known solutions and/or similar effects at a lower cost and with higher performance.
Within this aim, an object of the present invention is to provide a device for heating liquids that allows to heat a liquid from any initial temperature to a chosen final temperature, up to the gaseous state.
A further object of the present invention is to provide a device for heating liquids that ensures high safety, particularly for the subject— whether an ordinary user or a specialized technician— who handles the device, for example during installation or any operations for maintenance of said device, or during any operations for the maintenance of the machine or of the apparatus in which said device is installed.
Another object of the present invention is to provide a device for heating liquids that allows to obtain an energy saving with respect to the background art.
A further object of the present invention is to provide a device for heating liquids that does not need to be constantly active in order to be able to heat the liquid in an adequate manner.
Another object of the present invention is to provide a device for heating liquids that allows the heating of a quantity of liquid that is substantially limited to the actual requirement of the user.
A further object of the present invention is to provide a device for heating liquids that allows to avoid using a gas boiler— typically a methane boiler— consequently reducing the risks that derive from the use of this extremely flammable gas.
Likewise, an object of the present invention is to provide a device for heating liquids that allows to also avoid using an electric boiler.
Another object of the present invention is to provide a device for heating liquids that has reduced dimensions, thus reducing the space occupation.
Another object of the present invention is to provide a device for heating liquids that is highly reliable, relatively simple to provide and install, and economically competitive if compared with the background art.
This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a device for heating liquids, comprising at least one longitudinally extended hollow body, an electrical winding arranged around said hollow body and made of electrically conducting metallic material, and a longitudinally extended coil which passes inside said hollow body and is crossed internally by a stream of liquid and comprises electrically conducting metallic material, said electrical winding being configured to generate an electromagnetic field adapted to induce an electrical current in said coil for the electromagnetic induction heating of said coil, said coil being in thermal contact with said stream of liquid;
characterized in that:
said hollow body comprises a first end and a second end, the cavity of said hollow body comprising a first opening arranged at said first end and a second opening arranged at said second end; and
said first opening of said cavity of said hollow body is at least partially occluded by a first closure plate, and said second opening of said cavity of said hollow body is at least partially occluded by a second closure plate, said coil being enclosed within said hollow body by means of said first and second closure plates.
Further characteristics and advantages of the invention will become better apparent from the description of some preferred but not exclusive embodiments of the device for heating liquids according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein:
Figure 1 is a perspective view of an embodiment of the device for heating liquids according to the present invention;
Figures 2a and 2b are a perspective view and a sectional view, taken along a vertical plane, of a first variation of an embodiment of the device for heating liquids, according to the present invention;
Figures 3a and 3b are a perspective view and a sectional view, taken along a vertical plane, of a second variation of an embodiment of the device for heating liquids according to the present invention;
Figures 4a and 4b are a perspective view and a sectional view, taken along a vertical plane, of a third variation of an embodiment of the device for heating liquids according to the present invention;
Figure 5 is a top plan view of an embodiment of the device for heating liquids according to the present invention.
With reference to the figures, the device for heating liquids according to the invention, designated generally by the reference numeral 10, substantially comprises at least one longitudinally extended hollow body 12, an electrical winding 18 arranged around the hollow body 12, in particular around the outer wall of the latter, and a longitudinally extended coil 20 which passes within the hollow body 12, in particular through the cavity of the hollow body 12. Like the hollow body 12, the cavity of the hollow body 12 also is extended longitudinally.
The hollow body 12 is the supporting element of the heating device 10 and comprises a first end 14 and a second end 16. The cavity of the hollow body 12 comprises a first opening, arranged at the first end 14, and a second opening, arranged at the second end 16. The cavity of the hollow body 12 is delimited by the internal wall of the latter.
Advantageously, as shown in Figure 1, the first opening of the cavity of the hollow body 12 is occluded partially or completely by a first closure plate 25, which is arranged and fixed at the first end 14. Likewise, the second opening of the cavity of the hollow body 12 is partially or completely occluded by a second closure plate (not shown), which is arranged and fixed at the second end 16.
By way of example, the first closure plate 25 and the second closure plate can be fixed to the first end 14 and to the second end 16 of the hollow body 12, respectively, by virtue of interlocking couplings or fastened by means of threaded grubs.
In practice, the coil 20 is substantially enclosed within the hollow body 12 by means of the closure plates cited above, constituting a single body. In some embodiments, the end portions of the coil 20, in particular an inlet portion and an outlet portion, can protrude from the hollow body 12 and therefore from the single body.
The substantially complete closure of the coil 20 within the hollow body 12 by means of the closure plates ensures both a correct and safe operation of the device 10 according to the invention, particularly according to the operating specifications, and a correct and safe installation of said device 10 in a machine or an apparatus, without leaving room for any errors during installation.
As regards correct and safe operation, it is noted that if the coil 20 were a through coil but were not completely enclosed within the hollow body 12, there would be an alteration of the total inductance value of the device 10 according to the invention, which would produce malfunctions in the electronic power board 30, for example the failure of the corresponding components, and abnormal absorptions from the electrical power mains.
In particular, since the coil 20 comprises preferably ferromagnetic electrically conducting metallic material, said coil 20 would alter the total inductance value if it were not completely enclosed within the hollow body 12. Said coil 20 in fact has a magnetic coupling with the electrical winding 18 arranged around the hollow body 12. The device 10 according to the invention is configured so that the coil 20 and the electrical winding 18 of the hollow body 12 operate within certain limits or ranges of magnetic coupling. If this magnetic coupling between the coil 20 and the electrical winding 18 were not within the limits or ranges cited above, the device 10 according to the invention would run the risk of malfunctioning.
If even just one third of the length of the coil 20 were not enclosed within the hollow body 12, the absorptions from the electrical power mains would be up to two and a half times higher than those actually required during normal operation. For example, a condition of normal operation of the device 10 according to the invention for a given application may have an absorption from the electric power mains of 1 kW; if the coil 20 were enclosed for two thirds of its length in the hollow body 12, the absorption from the electrical power mains would be greater than 2.3 kW and would lead to the failure of the electronic power board 30.
As regards correct and safe installation, it is noted that the fact that the hollow body 12 and the coil 20 are substantially part of a single body speeds up the installation of the device 10 according to the invention on the part of the operator, who simply has to connect the two ends of the device 10, for example by means of the intake manifold 24 and the discharge manifold 26, and the electrical connections 32.
Another advantage of the monolithic solution, comprising the hollow body 12, the coil 20, the first closure plate 25 and the second closure plate, consists in that the cavity of the hollow body 12 in which the coil 20 heated by electromagnetic induction is arranged is not accessible during the operation of the device 10 according to the invention.
The hollow body 12 can have any geometry, any cross-section and any length, to be defined in each instance according to the requirements of the case. In the preferred and illustrated embodiments, the hollow body 12 has a circular cross-section. Accordingly, both the external wall of the hollow body 12 and the internal wall of the hollow body 12 have a circular cross-section. In the preferred and illustrated embodiments, the hollow body 12 has a tubular shape, i.e. it is a cylindrical hollow body of variable length. In other embodiments, which are different from the preferred and illustrated ones, the hollow body 12 is frustum- shaped. In other embodiments, which are different from the preferred and illustrated ones, the hollow body 12 has a simple, preferably regular, polygonal cross-section, such as for example a square cross-section, a rectangular cross-section, a hexagonal cross-section, and so forth.
The hollow body 12 can be made of any heat-resistant material, such as for example a plastic material (for example polyamide 66). Preferably, the hollow body 12 is made of an electrically insulating material.
The electrical winding 18 of the heating device 10, which as mentioned is arranged around the hollow body 12, is made of electrically conducting metallic material, for example, copper or aluminum of the multistranded or solid-core type. In a preferred embodiment of the invention, the electrical winding 18 is arranged in contact with the external wall of the hollow body 12. In another embodiment of the invention, the electrical winding 18 is arranged proximate to the external wall of the hollow body 12. In the preferred and illustrated embodiments, in which the hollow body 12 has a circular cross-section, the electrical winding 18 has a cylindrical helical shape, with a pitch that can vary according to the requirements of the case.
Advantageously, as shown in Figures 1 and 4, the electrical winding 18 is covered externally by an insulating layer 22. In general, the insulating layer 22 is made of any electrically and thermally insulating material, for example an epoxy resin, a silicone resin, or a thermoplastic resin. Preferably, the insulating layer 22 is made of a thermoplastic resin, such as for example polyethylene terephthalate (e.g. Mylar®).
The electrical winding 18 is configured to transfer the energy required for the electromagnetic induction heating of the coil 20. In particular, the electrical winding 18 is configured to generate an electromagnetic field that is suitable to induce an electrical current in the coil 20 for the electromagnetic induction heating of said coil 20. In practice, the electrical winding 18 acts as an inductor or a coil.
In general, electromagnetic induction heating is a method that has been developed to heat electrically conducting materials, in particular ferromagnetic materials. Electromagnetic induction heating entails that the alternating electrical current flows across the electrical winding 18, which, by generating an electromagnetic field, induces the same alternating electrical current to the coil 20, heating the latter. This physical process is known as an electromagnetic induction or Faraday’s law.
After being heated by electromagnetic induction, the coil 20 transfers heat toward the stream of liquid that flows inside it, in particular by means of the contact between the coil 20 and the liquid.
In practice, the alternating electrical current induced in the coil 20 heats it to a desired temperature, so that the stream of liquid that flows within the coil 20 is in turn heated.
The heating device 10 according to the invention furthermore comprises at least one electronic power board 30 which is connected to the electrical winding 18, in particular to its ends, by means of electrical cables 32, for example of the multistranded or solid-core type. Advantageously, the electrical connections 32 from the electronic power board 30 to the electrical winding 18 have a length that is less than or equal to one meter. Obviously, it is possible to also use electrical connections 32 longer than one meter, but in this case there is a considerable decrease in the delivered power.
The electronic power board 30 is powered by the electric power distribution mains. The electronic power board 30 is configured to supply the electrical winding 18 with the alternating current required to generate the electromagnetic field for the electromagnetic induction heating of the coil 20. In practice, the electronic power board 30 operates like a radiofrequency electric current generator.
The operating frequency value or range of the electronic power board 30 depends exclusively on the desired temperature, on the quantity of liquid to be heated that flows within the coil 20, and on the heating coefficient of the liquid being considered. The coil 20 of the heating device 10, which as mentioned passes within the hollow body 12, is a tube or duct that is crossed internally by the stream of liquid to be heated. In one embodiment, the coil 20 is made of a preferably ferromagnetic electrically conducting metallic material. In another embodiment, the coil 20 is made of silicone material, i.e., silicone- based material, covered by a braid made of electrically conducting, preferably ferromagnetic, metallic material. This combination of silicone material and metallic braid allows an easier construction of the coil 20 and extends the possibilities of use of the device 10 according to the invention, for example in the food sector.
The coil 20 is in thermal contact with the stream of liquid. In particular, the coil 20 is configured to transfer heat toward the stream of liquid that flows inside it. The stream of liquid that exits from the coil 20 can reach any temperature, up to the gaseous state.
Furthermore, the coil 20 is configured to contain the stream of liquid to be heated and to guide its flow from an inlet portion of said coil 20, located for example proximate to the first end 14 of the hollow body 12 and/or proximate to the first opening of the cavity of the hollow body 12, to an outlet portion of said coil 20, for example arranged proximate to the second end 16 of the hollow body 12 and/or proximate to the second opening of the cavity of the hollow body 12.
The coil 20 can have any geometry, any cross-section and any length, to be defined in each instance depending on the requirements of the case. In the preferred and illustrated embodiments, the coil 20 has a circular cross- section. In one embodiment of the invention, for example as shown in Figures 2a, 2b, 3a and 3b, the coil 20 has a helical, preferably cylindrical shape, with a pitch that can vary according to the requirements of the case.
With particular reference to Figures 2a and 2b, in a variation of an embodiment the coil 20 has a helical shape, preferably a cylindrical shape, and at least one part of its turns, preferably all of them, is arranged in contact with the internal wall of the hollow body 12.
With particular reference to Figures 3 a and 3b, in another variation of an embodiment the coil 20 has a helical, preferably cylindrical shape, and at least one part of its turns, preferably all, is associated with the hollow body 12. In practice, in this variation the coil 20 and the hollow body 12 are associated monolithically.
In another variation (not shown) of an embodiment, the coil 20 has a helical, preferably cylindrical shape and at least one part of its turns, preferably all, are arranged proximate to the internal wall of the hollow body 12.
With particular reference to Figures 4a and 4b, in another embodiment of the invention the coil 20 is parallel to the central longitudinal axis of the hollow body 12 and preferably coincides therewith.
The shape and/or size of some components of the heating device 10 according to the invention, such as for example the diameter of the hollow body 12 or the curvatures and the diameter of the coil 20, depend exclusively on the desired temperature, on the quantity of liquid to be heated that flows within the coil 20, and on the heating coefficient of the liquid being considered.
In one embodiment of the invention, as shown in Figure 1, the heating device 10 furthermore comprises an intake manifold 24 and a discharge manifold 26 which are configured to connect the coil 20 to a system of ducts for the flow of the liquid. The intake manifold 24 is connected to the inlet of the coil 20, for example arranged proximate to the first end 14 of the hollow body 12 and/or proximate to the first opening of the cavity of the hollow body 12. The discharge manifold 26 is connected to the output of the coil 20, for example arranged proximate to the second end 16 of the hollow body 12 and/or proximate to the second opening of the cavity of the hollow body 12. Optionally, the intake manifold 24 is coupled to the first closure plate 25, which as mentioned is arranged at the first end 14 of the hollow body 12, and the discharge manifold 26 is coupled to the second closure plate, which as mentioned is arranged at the second end 16 of the hollow body 12.
In one embodiment of the invention, as shown in Figure 1, the heating device 10 furthermore comprises an electric valve 28 of the three-way type, which is configured to load and discharge the liquid in the coil 20. Preferably, the electric valve 28 is associated with the discharge manifold 26.
During loading, the electric valve 28 is configured to load the heat liquid to be heated into the hydraulic circuit, in particular into the coil 20, before the operations for heating (and subsequent dispensing), i.e. before the electromagnetic induction heating of said coil 20. The flow of the stream of liquid in the coil 20 can occur by gravity or by means of a pump or by means of the pressure of a water system. In practice, the electric valve 28 opens the circulation of the liquid inside the coil 20 before the device 10 according to the invention is on. When the electric valve 28 opens the circulation of the liquid in the coil 20, the device 10 according to the invention can start the heating operations. This is useful to avoid the "dry" operation of the device 10, i.e. without flow of the stream of liquid inside it, in particular in the coil 20. The "dry" operation of the device 10 can in fact lead to very high temperatures in a few seconds and to the consequent damage of said device 10.
During discharge, the electric valve 28 is configured to discharge the residual liquid that is present within the hydraulic circuit, in particular in the coil 20, after the operations for heating (and subsequent dispensing), i.e., after the electromagnetic induction heating of said coil 20. In practice, the electric valve 28 does not leave liquid inside the coil 20 after the device 10 according to the invention has been turned off. This discharge operation performed by the electric valve 28 is useful to prevent the liquid from stagnating within the hydraulic circuit, in particular in the coil 20, and said liquid from freezing in the case of low temperatures. In an alternative embodiment, the three-way electric valve 28 can be replaced by an electric loading valve, preferably associated with the intake manifold 24, and an electric discharge valve, preferably associated with the discharge manifold 26.
In one embodiment of the invention, the device 10 for heating liquids according to the invention comprises a plurality of hollow bodies 12 which are mutually connected in series, in a number that can vary according to the requirements of the case, where the coil 20 passes within the plurality of hollow bodies 12. Preferably, the hollow bodies 12 of said plurality all have the same cross-section.
In general, the heating device 10 according to the invention is controlled and operated by one or more electronic boards (including the electronic power board 30) which can have different configurations of the hardware and/or software type, to be defined in each instance according to the requirements of the case, for example on the basis of the length of the hollow body 12 and of the coil 20, or on the basis of the desired temperature that the liquid must reach in output from the coil 20.
Therefore, the adjustment of the temperature of the liquid in output from the coil 20 occurs by means of an appropriate hardware and/or software configuration of the electronic boards cited above. For example, by means of these configurations it is possible to set different temperature thresholds of the liquid in output from the coil 20.
In one embodiment of the invention, for the indirect measurement of the temperature of the liquid and the subsequent adjustment of said temperature, the heating device 10 furthermore comprises a thermistor which is arranged in thermal contact with the coil 20, preferably with an end portion of the coil 20, and is functionally connected to a control unit of the heating device 10 according to the invention, and optionally also to the electronic power board 30. The thermistor can be in contact with the external wall or the internal wall of the coil 20. The thermistor can be arranged at any one of the closure plates of the openings of the cavity of the hollow body 12.
In this embodiment, the thermistor is characterized according to the temperature detected on the coil 20. The thermistor is sensitive to the temperature of the coil 20. The thermistor is configured to detect the temperature of the coil 20 and to report the temperature detected on the coil 20 to the control unit, for example by means of an adapted circuit.
In this embodiment also, the control unit is configured to calculate the temperature of the stream of liquid that flows inside the coil 20 on the basis of the temperature detected by the thermistor on the coil 20 by means of an appropriate algorithm. The control unit is furthermore configured to control the electronic power board 30 and vary the operating frequency of said electronic power board 30 on the basis of the power required to reach the desired temperature of the liquid with respect to the actual temperature calculated beforehand by the control unit.
In an alternative embodiment of the invention, for the direct measurement of the temperature of the liquid and the subsequent adjustment of said temperature the heating device 10 furthermore comprises a thermistor which is arranged in thermal contact with the stream of liquid that flows inside the coil 20 and is functionally connected to the control unit of the heating device 10 according to the invention and optionally also to the electronic power board 30. The thermistor can be arranged at any one of the closure plates of the openings of the cavity of the hollow body 12.
In this embodiment, the thermistor is characterized on the basis of the temperature detected on the stream of liquid. The thermistor is sensitive to the temperature of the stream of liquid. The thermistor is configured to detect the temperature of the stream of liquid that flows inside the coil 20 and to report to the temperature detected on the stream of liquid to the control unit, for example by means of an appropriate circuit.
In this embodiment also, the control unit is configured to control the electronic power board 30 and vary the operating frequency of said electronic power board 30 on the basis of the power required to reach the desired temperature of the liquid with respect to the actual temperature detected previously by the thermistor.
In a preferred embodiment, the thermistor of the heating device 10 according to the invention is of the NTC type (from the English Negative Temperature Coefficient), in practice with a resistance that decreases as the temperature increases.
The adjustment of the temperature of the liquid has a precision of less than 0.5°C and allows minimum use of the electric power absorbed by the device 10 according to the invention to heat the liquid inside it.
For example, assume a closed hydraulic circuit which contains a given quantity of liquid to be heated which flows inside it. The control unit of the heating device 10 according to the invention, by interacting with the thermistor arranged in thermal contact with the coil 20, is capable of adjusting the minimum power of the electromagnetic induction that is needed to bring the liquid to desired temperature or keep it thereat.
The control unit of the heating device 10 allows to consume only the quantity of liquid and power that are strictly necessary by means of the adjustment of the temperature of the liquid and the management of the electric valve 28.
In one embodiment of the invention, the heating device 10 furthermore comprises a safety device 45 which is arranged in thermal contact with the coil 20, preferably with an end portion of the coil 20, and is functionally connected to the electronic power board 30. The safety device 45 can be in contact with the external wall or the internal wall of the coil 20. The safety device 45 can be arranged at any one of the closure plates of the openings of the cavity of the hollow body 12.
The safety device 45 is sensitive to the temperature of the coil 20. The safety device 45 is configured to detect the temperature of the coil 20 and to trip if the temperature of the coil 20 exceeds a threshold value. In particular, the safety device 45 is configured to stop the electromagnetic induction heating of the coil 20, interrupting the electric power supply of the electronic power board 30, if a threshold temperature (preset for example to 120°C) is exceeded on the coil 20. In practice, the safety device 45 is configured to stop the heating device 10 according to the invention if its coil 20 reaches a temperature that exceeds the threshold value (for example 120°C).
When the threshold value of the temperature of the coil 20 is exceeded, the safety device 45 trips, opening the circuit, therefore acting as a breaker, and interrupting the electric power supply of the electronic power board 30. After the safety device 45 has tripped, the heating device 10 according to the invention must cool down and be turned on again. The heating device 10 restarts when the temperature of the coil 20 returns below the threshold value.
In a preferred embodiment, the safety device 45 of the heating device 10 according to the invention comprises a metallic flange which is arranged in thermal contact with the coil 20 and a temperature regulator which is associated with the flange and is functionally connected to the electronic power board 30. Advantageously, the temperature regulator comprises a resettable thermal safety (for example, a thermal safety which can be reset at 120°C), which is also metallic and associated with the flange for example by screwing.
The safety device 45 allows, in the case of malfunction, if any, to stop the heating device 10 according to the invention and prevent the coil 20 from melting the hollow body 12 or, worse still, causing a fire of the components. In any fault situation, the safety device 45 allows the temperature of the coil 20 to remain under control, allows the electronic power board 30 not to be damaged, and allows the operating temperature of the coil 20, and therefore of the heating device 10, to remain within the safety limits provided by the applicable statutory provisions and by the technical specifications of the materials used.
In one embodiment of the invention, as shown in Figure 5, the heating device 10 is included in a box-shaped body 50 which is adapted to protect the various components, in particular the hollow body 12, the electrical winding 18 and the electronic power board 30. The liquid to be heated enters the coil 20 of the heating device 10 through, in the following order: an intake port 36, an intake duct 34 and the intake manifold 24. The heated liquid exits from the coil 20 of the heating device 10 through, in the following order: the discharge manifold 26, a discharge duct 38 and an outlet port 40.
The operation of one embodiment of the device 10 for heating liquids according to the invention is briefly summarized hereinafter.
Initially, the liquid to be heated to the desired temperature enters the coil 20 of the heating device 10, which as mentioned passes within the hollow body 12. During the flow of the stream of liquid within the coil 20, the electrical winding 18 of the heating device 10, which as mentioned is arranged around the hollow body 12, generates an electromagnetic field that is adapted to induce an electrical current for the electromagnetic induction heating of said coil 20. The coil 20 then transfers heat toward the stream of liquid that flows inside it, in particular by means of the thermal contact between the coil 20 and the liquid. Finally, the liquid heated to the desired temperature exits from the coil 20 of the heating device 10.
In practice it has been found that the invention fully achieves the intended aim and objects. In particular, it has been shown that the device for heating liquids thus conceived allows to overcome the quality limitations of the background art, since it allows to achieve better effects than those obtainable with known solutions and/or similar effects at lower cost and with a higher performance.
One advantage of the device for heating liquids according to the present invention resides in that it allows to heat a liquid from any initial temperature to a desired final temperature, up to the gaseous state, during the travel time inside the coil.
A further advantage of the device for heating liquids according to the present invention resides in that it ensures high safety, in particular for the subject— whether an ordinary user or a specialized technician— who handles the device, for example during installation or during any operations for the maintenance of said device, or during any operations for maintenance of the machine or of the apparatus in which said device is installed.
Another advantage of the device for heating liquids according to the present invention resides in that it allows to obtain a high energy saving with respect to the background art.
A further advantage of the device for heating liquids according to the present invention resides in that it does not need to be constantly active in order to be able to heat the liquid adequately.
Another advantage of the device for heating liquids according to the present invention resides in that it allows the heating of a quantity of liquid that is substantially limited to the strict amount necessary.
A further advantage of the device for heating liquids according to the present invention resides in that it allows to avoid having a gas boiler— typically a methane boiler— consequently reducing the risks that arise from the use of this extremely flammable gas. Likewise, an advantage of the device for heating liquids according to the present invention resides in that it allows to avoid having an electric boiler as well.
Another advantage of the device for heating liquids according to the present invention resides in that it has reduced dimensions, thus reducing the space occupation considerably.
Not least advantage of the device for heating liquids according to the present invention resides in that it is highly reliable, relatively simple to provide and install, and economically competitive if compared with the background art.
Although the device for heating liquids according to the invention has been conceived in particular for operations for heating water, milk or oils to be used in the civil or industrial field for countless purposes, for example for domestic heating (i.e., warm running water), it can in any case be used more generally to heat any type of liquid or to produce steam.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. All the details may furthermore be replaced with other technically equivalent elements.
In practice, the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.
To conclude, the scope of the protection of the claims must not be limited by the illustrations or preferred embodiments shown in the description by way of example, but rather the claims must comprise all the characteristics of patentable novelty that reside in the present invention, including all the characteristics that would be treated as equivalents by the person skilled in the art.
The disclosures in Italian Patent Application no. 102019000003373, from which this application claims priority, are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A device (10) for heating liquids, comprising at least one longitudinally extended hollow body (12), an electrical winding (18) arranged around said hollow body (12) and made of electrically conducting metallic material, and a longitudinally extended coil (20) which passes inside said hollow body (12) and is crossed internally by a stream of liquid and comprises electrically conducting metallic material, said electrical winding (18) being configured to generate an electromagnetic field adapted to induce an electrical current in said coil (20) for the electromagnetic induction heating of said coil (20), said coil (20) being in thermal contact with said stream of liquid;
characterized in that:
said hollow body (12) comprises a first end (14) and a second end (16), the cavity of said hollow body (12) comprising a first opening arranged at said first end (14) and a second opening arranged at said second end (16); and
said first opening of said cavity of said hollow body (12) is at least partially occluded by a first closure plate (25), and said second opening of said cavity of said hollow body (12) is at least partially occluded by a second closure plate, said coil (20) being enclosed within said hollow body (12) by means of said first and second closure plates.
2. The heating device (10) according to claim 1, characterized in that it comprises furthermore at least one electronic power board (30) connected to said electrical winding (18), said electronic power board (30) being configured to supply said electrical winding (18) with an electric current for generating said electromagnetic field for the electromagnetic induction heating of said coil (20).
3. The heating device (10) according to claim 1 or 2, characterized in that said electrical winding (18) is covered externally by an insulating layer (22).
4. The heating device (10) according to any one of claims 1 to 3, characterized in that said coil (20) has a helical shape.
5. The heating device (10) according to claim 4, characterized in that at least one part of the turns of said coil (20) is arranged in contact with the internal wall of said hollow body (12).
6. The heating device (10) according to claim 4, characterized in that at least one part of the turns of said coil (20) is associated with said hollow body (12).
7. The heating device (10) according to claim 4, characterized in that at least one part of the turns of said coil (20) is arranged proximate to the internal wall of said hollow body (12).
8. The heating device (10) according to any one of claims 1 to 3, characterized in that said coil (20) is parallel to the central longitudinal axis of said hollow body (12).
9. The heating device (10) according to any one of the preceding claims, characterized in that said coil (20) comprises an inlet arranged proximate to said first end (14) of said hollow body (12) and an outlet arranged proximate to said second end (16) of said hollow body (12).
10. The heating device (10) according to any one of claims 1 to 9, characterized in that said hollow body (12) has a circular cross-section.
11. The heating device (10) according to any one of claims 1 to 9, characterized in that said hollow body (12) has a simple polygonal, preferably regular, cross-section.
12. The heating device (10) according to any one of the preceding claims, characterized in that it further comprises an electric valve (28) configured to load said liquid into said coil (20), before said electromagnetic induction heating, and to discharge the residue of said liquid that is present in said coil (20) after said electromagnetic induction heating.
13. The heating device (10) according to any one of claims 2 to 12, characterized in that it comprises furthermore a safety device (45) arranged in thermal contact with said coil (20) and functionally connected to said electronic power board (30), said safety device (45) being configured to detect the temperature of said coil (20) and stop said electromagnetic induction heating of said coil (20), interrupting the electric power supply of said electronic power board (30), if a threshold temperature is exceeded on said coil (20).
14. The heating device (10) according to any one of the preceding claims, characterized in that it comprises furthermore an intake manifold (24) and a discharge manifold (26) configured to connect said coil (20) to a system of ducts for said stream of liquid.
15. The heating device (10) according to any one of the preceding claims, characterized in that it comprises a plurality of said hollow bodies (12) connected in series, said coil (20) passing within said plurality of hollow bodies (12).
PCT/IB2020/052023 2019-03-08 2020-03-09 Device for heating liquids WO2020183344A1 (en)

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CH00485/21A CH716873B1 (en) 2019-03-08 2020-03-09 Device for heating liquids.
EP20713102.0A EP3935917A1 (en) 2019-03-08 2020-03-09 Device for heating liquids

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IT102019000003373A IT201900003373A1 (en) 2019-03-08 2019-03-08 Device for heating liquids.
IT102019000003373 2019-03-08

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Publication number Priority date Publication date Assignee Title
CN113546823A (en) * 2021-06-17 2021-10-26 美克钢纤维(马鞍山)有限公司 Steel fiber drying device

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FR2525122A1 (en) * 1982-04-16 1983-10-21 Inst Francais Du Petrole Laboratory appts. for studying steam cracking - with inductively heated helical tube reactor, has turbulent flow, reducing wall effects
JP2003317915A (en) * 2002-04-26 2003-11-07 Omron Corp Fluid heating apparatus
US20050098486A1 (en) * 2003-11-07 2005-05-12 Chien-Ku Hung Magnetic energy wave device
CN102607177A (en) * 2012-02-28 2012-07-25 佛冈县新能达节能环保有限公司 Heat-conduction oil furnace heater
KR101192976B1 (en) * 2012-05-03 2012-10-23 곽영진 Vacuumed heating equipment using electromagnetic induction
EP2868242A1 (en) * 2013-10-29 2015-05-06 Rheavendors Services S.P.A. Device and method for heating water in a machine for making and dispensing drinks

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2525122A1 (en) * 1982-04-16 1983-10-21 Inst Francais Du Petrole Laboratory appts. for studying steam cracking - with inductively heated helical tube reactor, has turbulent flow, reducing wall effects
JP2003317915A (en) * 2002-04-26 2003-11-07 Omron Corp Fluid heating apparatus
US20050098486A1 (en) * 2003-11-07 2005-05-12 Chien-Ku Hung Magnetic energy wave device
CN102607177A (en) * 2012-02-28 2012-07-25 佛冈县新能达节能环保有限公司 Heat-conduction oil furnace heater
KR101192976B1 (en) * 2012-05-03 2012-10-23 곽영진 Vacuumed heating equipment using electromagnetic induction
EP2868242A1 (en) * 2013-10-29 2015-05-06 Rheavendors Services S.P.A. Device and method for heating water in a machine for making and dispensing drinks

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113546823A (en) * 2021-06-17 2021-10-26 美克钢纤维(马鞍山)有限公司 Steel fiber drying device

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