Use of moving element to produce heat

• US 6,281,611 B1
• Filed: 04/11/2000
• Issued: 08/28/2001
• Est. Priority Date: 02/10/1998
• Status: Expired due to Fees

• Current Assignee: Light Sciences Oncology, Inc.
• Original Assignee: Light Sciences Corporation
• Inventors: Chen, James C., Huston, Darrin
• Primary Examiner(s): Mullins, Burton S.
• Application Number:
  US09/548,385
• Time in Patent Office: 504 Days
• Field of Search: 219/201, 219/209, 219/635, 219/634, 310/171, 310/40.R, 310/50, 310/46, 310/156, 310/104, 310/112, 310/103, 310/152
• US Class Current: 310/171
• CPC Class Codes: A47J 36/02 Selection of specific materials, e.g. heavy bottoms with copper inlay or with insulating inlay
• CPC Class Codes: A47J 36/26 Devices for warming vessels containing drinks or food, especially by means of burners Warming devices with a burner, e.g. using gasoline; Travelling cookers, e.g. using petroleum or gasoline with one burner
• CPC Class Codes: A61F 2250/0001 Means for transferring electromagnetic energy to implants
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H01F 38/12 Ignition, e.g. for IC engines
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02K 21/12 with stationary armatures and rotating magnets
• CPC Class Codes: H02K 21/24 with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• CPC Class Codes: H02K 35/02 with moving magnets and stationary coil systems
• CPC Class Codes: H02K 5/1282 the partition wall in the air-gap being non cylindrical
• CPC Class Codes: H02K 7/1807 Rotary generators H02K7/006 takes precedence
• CPC Class Codes: H02K 7/1876 with reciprocating, linearly oscillating or vibrating parts
• CPC Class Codes: H05B 6/1236 adapted to induce current in a coil to supply power to a device and electrical heating devices powered in this way
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A method and apparatus for heating substances such as beverages, soups, chemicals, etc., with heat produced by circulating electrical eddy currents. In one form of the device, a magnetic flux generating base produces a varying magnetic field by using an electric motor to move a plurality of permanent magnets. The varying magnetic field induces the eddy currents to circulate in a ferromagnetic conductor that is sealed in the bottom of a container resting on the magnetic flux generating base. Losses due to the eddy current produce heat that is transferred into the substance within the container. In another embodiment, the motor moves one or more magnetic flux shunts to vary the magnetic field experienced by the ferromagnetic conductor. The presence of the container on the magnetic flux generating base can be detected and used to control the operation of the electrical motor. An indicator is provided in one embodiment to alert a user when the electrical motor is energized and the substance in the container is being heated.

Claims

1. Apparatus for heating a substance, comprising:

(a) a container adapted to hold the substance, said container including;

(i) a base portion;

(ii) a ferromagnetic conductor disposed within the base portion; and

(ii) an upper portion connected to the base portion, said upper portion being adapted to receive the substance so that the substance is in thermal heat transfer relationship with the base portion of the container; and

(b) a flux generator including;

(i) a housing adapted to support the base portion of the container;

(ii) a varying magnetic field generator that includes at least one permanent magnet and is disposed within the housing of the flux generator; and

(iii) a prime mover drivingly coupled to an element of the magnetic field generator, causing said element of the magnetic field generator to move relative to the ferromagnetic conductor, movement of said element of the magnetic field generator producing a varying magnetic field that induces an electrical eddy current to circulate within the ferromagnetic conductor, thereby generating heat due to eddy current losses, so that the substance in the container is heated by the heat transferred through the base portion of the container.

2. The apparatus of claim 1, wherein the prime mover comprises an electric motor.

3. The apparatus of claim 1, wherein said at least one permanent magnet is mounted on the element that is moved by the prime mover, movement of said at least one permanent magnet generating the varying magnetic field experienced by the ferromagnetic conductor.

4. The apparatus of claim 1, wherein said at least one permanent magnet includes a rare earth alloy.

5. The apparatus of claim 1, wherein the varying magnetic field generator includes a plurality of permanent magnets and a movable support on which the plurality of permanent magnets are mounted, said prime mover causing the movable support to move relative to the ferromagnetic conductor, thereby varying the magnetic field along a path that includes the ferromagnetic conductor.

6. The apparatus of claim 5, wherein the movable support is caused to reciprocate back and forth in a reciprocating motion.

7. The apparatus of claim 1, wherein the element of the magnetic field generator that is drivingly coupled to the prime mover comprises a magnetic flux shunt that is moved by the prime mover, to periodically shunt a magnetic field produced by said at least one permanent magnet of the varying magnetic field generator, causing the magnetic field produced by said at least one permanent magnet to vary along a path that includes the ferromagnetic conductor.

8. The apparatus of claim 1, further comprising an adjustment member that is selectively actuated to control a speed with which the element of the magnetic field generator is moved.

9. The apparatus of claim 1, wherein the upper portion of the container includes a thermally insulating layer.

10. The apparatus of claim 9, wherein the thermally insulating layer of the upper portion of the container comprises an external wall and an internal wall separated by a sealed air space.

11. The apparatus of claim 1, wherein a receptacle is defined in the flux generator housing, said receptacle having a size and shape adapted to receive the base portion of the container.

12. The apparatus of claim 1, wherein the ferromagnetic conductor comprises a soft iron metal.

13. The apparatus of claim 1, further comprising:

(a) a coil of wire wrapped around the ferromagnetic conductor; and

(b) a heating element connected to the coil of wire and disposed in the container so as to be in heat transfer communication with the substance in the container, wherein as current flows through the ferromagnetic conductor a current is induced to flow in the coil of wire that is used to energize the heating element to further heat the substance in the container.

14. Apparatus for heating a liquid, comprising:

(a) a flux generating base comprising;

(i) an electric motor having a drive shaft;

(ii) a rotor, operatively coupled to the drive shaft of the electric motor to be rotated thereby and having attached thereto a plurality of permanent magnets, each permanent magnet having a north pole face and a south pole face oriented generally parallel to a rotational plane of the rotor; and

(iii) a housing in which the electric motor and the rotor are disposed, a surface of the housing defining a supporting interface; and

(b) a container in which the liquid is held, including;

(i) a container base that rests on the supporting interface of the housing;

(ii) a ferromagnetic conductor disposed in the container base, and

(iii) an upper portion sealingly connected to the container base, said upper portion being adapted to hold the liquid in thermal contact with the container base, said motor rotating said rotor to produce a varying magnetic field that causes eddy currents to circulate within the ferromagnetic conductor when the container is resting on the supporting interface, said eddy currents producing heat that is transferred into the liquid through the container base at that time.

15. The apparatus of claim 14, wherein the supporting interface of the flux generating base is sized and shaped to receive the container base.

16. The apparatus of claim 14, further comprising a sensor disposed in the flux generating base that produces a signal indicative of whether the container base is resting on the supporting interface of the flux generating base.

17. The apparatus of claim 16, further comprising a permanent magnet disposed in the container base, said sensor comprising one of a Hall-effect sensor and a reed switch that changes the signal in response to the permanent magnet in the container base being position in proximity of said sensor when the container is rested on the supporting interface.

18. The apparatus of claim 16, wherein the electric motor is energized in response to the signal produced by the sensor, so that the rotor is only drivingly rotated by the electric motor when the container base is resting on the supporting interface of the flux generating base.

19. The apparatus of claim 14, further comprising an indicator that indicates when the electric motor in the flux generating base is operating.

20. The apparatus of claim 14, wherein the plurality of permanent magnets are disposed at different radii from a center of the rotor.

21. The apparatus of claim 14, wherein the electric motor is powered by a DC voltage supplied by a storage battery.

22. The apparatus of claim 21, further comprising an electric cord that includes an automobile cigarette lighter receptacle adapter at a first end and a second end connected to the electric motor, said electric cord supplying the DC voltage to the electric motor when the automobile cigarette lighter receptacle adapter is connected into an automobile cigarette lighter receptacle.

23. The apparatus of claim 14, wherein the container base further comprises a material having a high thermal conductivity that is disposed between the ferromagnetic conductor and the liquid and sealed around a periphery to the upper portion of the container so as to ensure that the liquid does not contact the ferromagnetic conductor, said material providing a thermal communication between the ferromagnetic conductor and the liquid.

24. The apparatus of claim 23, wherein said material comprises a disk fabricated of a corrosion-resistant metal.

25. The apparatus of claim 14, wherein the ferromagnetic conductor comprises a central portion connected to a plurality of arms that extend radially from the central portion.

26. The apparatus of claim 25, wherein the ferromagnetic conductor is embedded in a material comprising the container base that has a high thermal conductivity.

27. The apparatus of claim 14, wherein the ferromagnetic conductor comprises a soft iron metal.

28. The apparatus of claim 14, wherein the varying magnetic field develops an attractive force drawing the ferromagnetic conductor toward the supporting interface of the flux generating base so as to assist in maintaining the container base in contact with the supporting interface.

29. The apparatus of claim 14, further comprising:

(a) a coil of wire wrapped around the ferromagnetic conductor; and

(b) a heating element connected to the coil of wire and disposed in the container so as to be in heat transfer communication with the liquid, wherein as current flows through the ferromagnetic conductor a current is induced to flow in the coil of wire that is used to energize the heating element to further heat the liquid.

30. A method for heating a substance by inductively coupling a varying magnetic field to a ferromagnetic conductor disposed in a container that contains the substance, comprising the steps of:

(a) positioning a ferromagnetic conductor sealed within the container proximate to a supporting interface of a base;

(b) providing a magnetic field; and

(c) moving an element in the base with a prime mover so that the element is moved relative to the ferromagnetic conductor, a varying magnetic field that is produced thereby being inductively coupled to the ferromagnetic conductor, causing an electrical eddy current to circulate in the ferromagnetic conductor, thereby producing eddy current losses that generate heat in the ferromagnetic conductor, a portion of said heat being transferred to the substance to heat it.

31. The method of claim 30, wherein the step of providing the magnetic field comprises the step of providing at least one permanent magnet.

32. The method of claim 31, wherein the step of moving the element comprises the step of moving said at least one permanent magnet.

33. The method of claim 32, wherein the step of moving the element comprises the step of moving said at least one permanent magnet about an axis in a circular path to vary the magnetic field produced by said at least one permanent magnet along a path that includes the ferromagnetic conductor.

34. The method of claim 32, wherein the step of moving the element comprises the step of reciprocating said at least one permanent magnet back and forth to vary the magnetic field produced thereby along a path that includes the ferromagnetic conductor.

35. The method of claim 30, further comprising the step of enhancing a magnetic flux linkage between magnetic poles of the permanent magnet and the ferromagnetic conductor.

36. The method of claim 35, wherein the step of enhancing the magnetic flux linkage comprises the step of providing a flux linkage bar for coupling a magnetic field from a pole of said at least one permanent magnet into the ferromagnetic conductor.

37. The method of claim 30, further comprising the step of selectively varying a maximum magnetic field intensity that is coupled to the ferromagnetic conductor.

38. The method of claim 37, wherein the step of selectively varying the maximum magnetic field intensity comprises the step of changing a speed with which the element is moved.

39. The method of claim 30, wherein the step of providing the magnetic field comprises the step of providing a plurality of permanent magnets.

40. The method of claim 39, wherein the plurality of permanent magnets are fixed relative to the base, and wherein the step of moving the element comprises the step of intermittently passing a flux shunt member adjacent to pole faces of the plurality of permanent magnets so as to provide a magnetic flux shunt path between the pole faces of the plurality of permanent magnets, said magnetic flux shunt path periodically shunting the magnetic field to vary it.

41. The method of claim 39, wherein the step of moving the element comprises the step of moving the plurality of permanent magnets back and forth past the ferromagnetic conductor to vary the magnetic field experienced by the ferromagnetic conductor.

42. The method of claim 30, further comprising the step of providing an indication of whether the container is resting on the base.

43. The method of claim 30, further comprising the step of providing an indication of whether the prime mover has been energized.

44. The method of claim 30, wherein a coil of wire connected to a heating element disposed in the container is wrapped around the ferromagnetic conductor so that a current is induced in the coil of wire when current flows through the ferromagnetic conductor, said current that is induced in the coil of wire energizing the heating element.