US20060132045A1 - Heating system and heater - Google Patents

Abstract

An inductively power heating system includes an inductive power source for supplying power to an inductive heater. The inductive heater may include a resistive heater and a multiple coil secondary. A heater control within the inductive heater may control the power supplied to the resistive heater, and thereby control the temperature of the resistive heater. The inductive heater may encapsulate the resistive heater, the multiple coil secondary and the heater control, thereby providing a sealed, inductive heater.

Description

BACKGROUND OF THE INVENTION
• Inductive electric heaters are in general use in several fields, such as medicine and printing. A heating slug of metal such as iron or steel is placed within proximity to an alternating electrical field. The alternating field induces currents within the slug, causing the slug to heat.
• This type of electric heater has been used in a variety of different applications. For example, the arrangement is used in fluid heaters, such as the one shown in U.S. Pat. No. 6,118,111, entitled “Fluid Heater” and issued to Nigel Brent Price et al. U.S. Pat. No. 4,032,740 entitled “Two-level temperature control for induction heating” and issued to Eugene Mittelmann shows an induction heating apparatus for heating work pieces.
• Inductive heating systems allow the heating of objects without providing electric current directly to the object or by running wires into the heating element, thereby allowing some degree of isolation of the heating slug from the rest of circuitry. However, such systems fail to provide sufficiently fine control of the temperature for some applications, and thereby limit their utility.
• Thus, an improved induction heating system is highly desirable.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows an inductive heating system.
• FIG. 2 shows a different embodiment for the circuit used within inductive heater.
• FIG. 3 shows inductive heater.
• FIG. 4 shows a plurality of heaters suspended within the container.
• FIG. 5 shows an electric frying pan using an inductive heating system.
• FIG. 6 shows a soldering iron using an inductive heating system.
DETAILED DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows an inductive heating system. Adaptiveinductive power supply10 provides power toinductive heater12. The operation of adaptiveinductive power supply10 has been described fully in patent application Ser. No. 10/689,499 and patent application Ser. No. 10/689,148, assigned to the assignee of this application. Both applications are hereby incorporated by reference.
• A short summary of the operation of adaptiveinductive power supply10 is provided. Inverter14 supplies power totank circuit16.Tank circuit16 is shown as a serial resonant tank circuit, but a parallel circuit tank circuit could also be used.Tank circuit16 consists oftank capacitor18,variable inductor20 andtank inductor22.
• Whilevariable inductor20 andtank inductor22 are shown as two separate inductors, one skilled in the art would recognize that a single variable inductor could be substituted for the two. Alternatively, a single fixed inductor could be used rather than a variable inductor. Similarly,tank capacitor18 could be either variable or fixed.
• Power source24energizes inverter14.Drive circuit26 controls the duty cycle and frequency ofinverter14.Controller28controls drive circuit26 as well astank capacitor18 andvariable inductor20.
• Circuit sensor30 provides information regarding the operation oftank circuit16 to controller28.Memory30 stores information relating to the operation ofpower supply10 as well as information regarding any devices supplied power bypower supply10.Transceiver32 is provided to allow communication betweencontroller28 and any external devices. The external devices could be devices powered bypower supply10 or the external devices could be a computer or a network. Whiletransceiver32 is shown for sending and receiving communication,transceiver32 could be either a transmitter or a receiver.
• Inductive heater12 is comprised of a multiple coil secondary40. Multiple coil secondary40 has been described in more detail in patent application Ser. No. 10/689,224, assigned to the assignee of this application which is hereby incorporated by reference. Multiple coil secondary40 is an inductive secondary allowinginductive heater12 to be powered bypower supply10 irregardless of the orientation of secondary40 with respect topower supply10. Alternatively, secondary40 could be comprised of a single coil.
• Inductive heater capacitor42 may be used to balance the impedance ofinductive heater12 so that optimum power transfer may occur.Heater resistor44 heats when a sufficient electric current is applied.Heater control46 regulates the current supplied toheater resistor44, and thus regulates the heat generated byheater resistor44.Heater control46 could be a thermostat or a more complicated control.
• Ifheater resistor44 was a self-limiting resistor, a heater control could be optional. A self-limiting heater adjusts the energy generated in relation to the surface temperature and ambient temperature. As the temperature increases the resistance within the heater increases, thus decreasing the wattage output.
• Inductive heater12 could be within an enclosure such that no component ofinductive heater12 would extend out of the enclosure. The enclosure could also be hermetically sealed. Alternatively, all of the components ofinductive heater42 could be integrally molded together in a casing material such as a thermally conductive plastic, such as CoolPoly Elastomer, manufactured by Cool Polymers, Inc., Warwick, R.I. Some thermally conductive such as CoolPoly D-Series polymers also provide electrical isolation. Suitable materials are liquid crystalline polymer and polyphenylene sulfide.
• Heater resistor44 could be one of several different devices. For example, it could be a self-limiting parallel circuit heating tape, such as the one sold by Bartec U.S. Corporation, Tulsa, Okla.; heating tape, sold by HTS/Amptek Company, Stafford, Tex.; insulated resistance wire, such as those sold by HTS/Amptek Company, Stafford, Tex.; flexible foil heaters, such as those sold by Minco Products, Inc., Minneapolis, Minn.; wire-wound rubber heaters, such as Minco Products, Inc., Minneapolis, Minn.; Omegalux Kapton Insulated Flexible Heaters, sold by Omega Engineering, Inc., Stamford, Conn.; or Omegalux Silicon Rubber Heaters, sold by Omega Engineering, Inc., Stamford, Conn.
• FIG. 2 shows another embodiment for the circuit used withininductive heater12. Inductive heater circuit100 consists of heater control101 attached to heater element104.Inductive heater12 includes a multiple coil secondary102 coupled with heater element104 and tank circuit106. Multiple coil secondary102 supplies power to power supply108. Alternatively, secondary120 could be single coil. Power supply108 is then used to energize heater transceiver110 and controller112. Controller112 controls the setting for variable capacitor114 and variable inductor116 to maximize the total efficiency ofinductive power supply10. Temperature sensor117 provides information regarding the temperature of the inductive heater to controller112. Tank circuit106 is shown as a series resonant circuit. As is well known in the art, a parallel resonant circuit could be used in its stead.
• Transceiver110 could be a wireless transmission device using a protocol such as Bluetooth, cellular, or IEEE 801.11. Alternatively transceiver110 could be either and active or passive RFID device. Transceiver110 may be used by the controller to send information from temperature sensor117 to power supply108. While transceiver110 is shown for sending and receiving communication,transceiver32 could be a transmitter or a receiver.
• Memory118 may be used by controller112 to control the operation of the heater. Additionally, memory118 may include a unique identifier for the heater, or a range of operating temperatures used by controller112 to control operation of the heater.
• FIG. 3 showsinductive heater150.Inductive heater150 includes aninductive heater control152 and twoheating elements154,156. The two heating elements are affixed to the ends ofenclosure158.Leads160,162 extend toheater control152 fromheating elements154,156.
• Heating elements154,156 can be affixed either to the exterior ofenclosure158, in which case the leads would extend though wall ofenclosure158. Alternatively,heating elements154,156 could be affixed to the interior ofenclosure158, in which case leads160,162 would not have to penetrate the wall ofenclosure158.
• Enclosure158 is shown as a cylinder. Obviously, other geometrical configurations forenclosure158 are possible, such as a sphere or a cube.Enclosure158 could be partially empty other than forheater control152. Alternatively,enclosure158 could be a solid.
• Heating elements154,156 are shown as affixed to opposite sides ofenclosure158. Additional heating elements could be disposed on the exterior ofenclosure158, or only a single heating element could be used. For example, a single heating element could be disposed about the central portion ofenclosure158 rather than having a heating element at each end ofenclosure158.
• Heat sink164 is located near the surface ofenclosure158. It is made of a material such as copper so as to assist in the accurate determination of the temperature outside ofenclosure158.Heat sink164 is coupled toheater control152 to allow monitoring byheater control152 of temperatures exterior toinductive heater150.
• Inductive heater150 could be provided withpropulsion system166. Ifinductive heater150 were for use within a fluid,propulsion system166 would allow the movement ofinductive heater150 within the fluid.Propulsion system166 is shown aselectric motor168 andpropeller170. Obviously,propulsion system166 could also be any one of a variety of methods such as a turbine or fan. Alternatively,propulsion system166 could be used to circulate fluid aroundheater150.
• FIG. 4 shows a plurality ofheaters200,202,204 suspended withincontainer206.Heaters200,202,204 are shown as cubical heaters.Heaters200,202,204 could be cylindrical, spherical, or any other suitable shape. The heating element forheaters200,202,204 could be on one or more surfaces ofheaters200,202,204.
• Inductive primary208 is disposed aboutcontainer206. Inductive primary208 could be disposed at the base ofcontainer206 or the top ofcontainer206.Heater control210 could be the same or similar toinductive power supply10 ofFIG. 1.
• Ifheaters200,202,204 andheater control210 were supplied with transceivers,heater control210 could energize the heaters to maintain the contents ofcontainer206 at a desired temperature. When supplied with temperature sensors,heaters200,202,204 send information regarding the temperature withincontainer206 could be provided toheater control210. Thus, heater control could also monitor the temperature of the contents ofcontainer206.
• The heaters described herein could be used in a variety of applications.FIG. 5 showselectric frying pan300.Frying pan300 has inductive secondary302 attached toheater control304.Heater control304 is coupled toheating element306. When placed near an inductive ballast, inductive secondary302 energizesheating element306.Heater control304, located in the handle ofelectric frying pan300, regulates the energy supplied toheating element306, and thereby controls the temperature withinelectric frying pan300.
• FIG. 6 showssoldering iron320.Heating element322 is coupled tocontroller324.Controller324 is located in the handle ofsoldering iron320. Inductive secondary326 is disposed within the handle ofsoldering iron320. When inductive secondary326 is energized,heater control324 provisions electrical energy toheating element322.
• The above description is of the preferred embodiment. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any references to claim elements in the singular, for example, using the articles “a,” “an,” “the,” or “said,” is not to be construed as limiting the element to the singular.

Claims (42)

1. A heating system comprising:

an adaptive inductive power supply; and

a heater receiving electrical power inductively from the adaptive inductive power supply.

2. The heating system ofclaim 1 where the heater further comprises a multiple coil secondary for receiving electrical power from the adaptive inductive power supply.

3. The heating system ofclaim 2 where the heater has a heating element.

4. The heating system ofclaim 3 where the heating element is one of self-limiting parallel circuit heating tape, insulated resistance wire, flexible foil heaters, wire-wound rubber heaters, insulated flexible heater, and silicon rubber heater.

5. The heating system ofclaim 4 where the heater has a heater control.

6. The heating system ofclaim 5 where the heater has a capacitor arranged to improve energy transfer from the adaptive inductive power supply to the heater.

7. The heating system ofclaim 1 where the adaptive inductive power supply has a power supply transceiver and the heater has a heater receiver for receiving communication from the adaptive inductive power supply.

8. The heating system ofclaim 1 where the adaptive inductive power supply has a power supply receiver and the heater has a heater transmitter for sending communication to the adaptive inductive power supply.

9. The heating system ofclaim 1 where the adaptive inductive power supply has a transceiver and the heater has a transceiver for communicating with the adaptive inductive power supply.

10. The heating system ofclaim 9 where the heater further comprises a controller.

11. The heating system ofclaim 10 where the heater further comprises a temperature sensor.

12. The heating system ofclaim 11 where the heater further comprises a memory.

13. The heating system ofclaim 3 where the heater is hermetically sealed.

14. The heating system ofclaim 3 where the heater is encapsulated within a plastic enclosure.

15. An inductively powered heater comprising:

a secondary for receiving power; and

an electrically resistive heater.

16. The inductively powered heater ofclaim 15 further comprising:

an enclosure having an exterior surface, the secondary being positioned within the enclosure and the electrically resistive heater positioned proximal to the exterior surface.

17. The inductively powered heater ofclaim 16 where the electrically resistive heater is positioned outside of the enclosure.

18. The inductively powered heater ofclaim 16 where the electrically resistive heater is positioned inside the enclosure.

19. The inductively powered heater ofclaim 16 further comprising a propulsion system.

20. The inductively powered heater ofclaim 19 where the propulsion system includes an electric motor.

21. The inductively powered heater ofclaim 20 where the electrically resistive heater is one of self-limiting parallel circuit heating tape, insulated resistance wire, flexible foil heaters, wire-wound rubber heaters, insulated flexible heater, and silicon rubber heater.

22. An inductively powered heater comprising:

an inductive secondary for receiving power;

an electrically resistive heater; and

an enclosure containing the inductive secondary and the electrically resistive heater such that the enclosure is fully sealed and unpenetrated.

23. The inductively powered heater ofclaim 22 further comprising:

a heater control contained within the enclosure for controlling energization of the inductively powered heater.

24. The inductively powered heater ofclaim 23 further comprising an adjustable impendence, the adjustable impedance being adjustable so as to alter power transferred from a primary to the inductive secondary.

25. The inductively powered heater ofclaim 24 further comprising a controller for controlling the adjustable impendence.

26. The inductively powered heater ofclaim 25 where the heater control includes a temperature sensor.

27. The inductively powered heater ofclaim 26 where the controller is responsive to the temperature sensor to change the adjustable impedance.

28. The inductively powered heater ofclaim 25 further comprising a receiver, the receiver coupled to the controller, the controller operating responsive to instructions received from the receiver to change the adjustable impedance to control an electric current.

29. The inductively powered heater ofclaim 27 further comprising a transmitter for transmitting information from the temperature sensor.

30. The inductively powered heater ofclaim 29 further comprising a propulsion system for moving the inductively powered heater.

31. The inductively powered heater ofclaim 30 where the propulsion system includes an electric motor.

32. A heating system for a material comprising:

an inductive primary; and

a plurality of inductive heaters, the inductive heaters receiving power from the inductive primary.

33. The heating system ofclaim 32 further comprising a heater control for controlling an electric current supplied to the plurality of inductive heaters.

34. The heating system ofclaim 33 where the heater control includes a receiver for receiving information from the plurality of inductive heaters.

35. The heating system ofclaim 34 where at least one of the plurality of inductive heaters has a transmitter for transmitting information to the heater control.

36. An inductively powered electric heater comprising:

an inductive secondary for receiving power;

an electric heater coupled to the inductive secondary and positioned around the inductive secondary;

and an enclosure containing the secondary the electrically resistive heater such that the enclosure is fully sealed and unpenetrated.

37. The inductively powered electric heater ofclaim 36 where the enclosure is an elastomeric material.

38. The inductively powered electric heater ofclaim 37 where the elastomeric material is a thermally conductive polymer.

39. The inductively powered electric heater ofclaim 38 where the thermally conductive polymer is one of liquid crystalline polymer and polyphenylene sulfide.

40. A method for heating a device comprising the steps of:

physically coupling a heating element with the device;

electrically coupling the heating element with one or more secondary coils;

providing an electrical signal from an inductive power supply to the secondary coil.

41. The method ofclaim 40, further comprising the step of coupling a heater control with the heating element.

42. The method ofclaim 41, further comprising the step of coupling a temperature sensor with the heating element.

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