Portable induction heater

• US 6,229,127 B1
• Filed: 01/25/1999
• Issued: 05/08/2001
• Est. Priority Date: 05/20/1998
• Status: Expired due to Term

• Current Assignee: Valro Manufacturing Limited
• Original Assignee: Valro Manufacturing Limited
• Inventors: Link, Roger V.
• Primary Examiner(s): Leung, Philip H.
• Application Number:
  US09/236,836
• Time in Patent Office: 834 Days
• Field of Search: 219/635, 219/634, 219/633, 219/647, 219/650, 219/663, 219/665, 219/672, 219/676, 219/677, 219/518
• US Class Current: 219/635
• CPC Class Codes: B29C 65/3612 comprising fillers
• CPC Class Codes: B29C 65/3644 being a ribbon, band or strip
• CPC Class Codes: B29C 65/3668 characterised by the means for supplying heat to said heated elements which remain in the join, e.g. special induction coils
• CPC Class Codes: B29C 65/3676 being metallic
• CPC Class Codes: B29C 65/368 with a polymer coating
• CPC Class Codes: B29C 65/46 heated by induction
• CPC Class Codes: B29C 65/4875 being spherical, e.g. particles or powders
• CPC Class Codes: B29C 65/489 being metals
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/43 Joining a relatively small portion of the surface of said articles B29C66/45 takes precedence
• CPC Class Codes: B29C 66/45 Joining of substantially the whole surface of the articles methods or apparatus for laminating B32B37/00
• CPC Class Codes: B29C 66/474 said single elements being substantially non-flat
• CPC Class Codes: B29C 66/72343 for liquids
• CPC Class Codes: B29C 66/742 to metals or their alloys
• CPC Class Codes: B29C 66/8122 characterised by the composition of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
• CPC Class Codes: B29C 66/81811 of the welding jaws
• CPC Class Codes: B29C 66/81812 the welding jaws being cooled from the outside, e.g. by blowing a gas or spraying a liquid
• CPC Class Codes: B29C 66/861 Hand-held tools
• CPC Class Codes: B29C 66/8612 Ironing tool type
• CPC Class Codes: B29C 66/8618 being battery operated
• CPC Class Codes: B29C 66/872 : Starting or stopping procedures
• CPC Class Codes: B29C 66/9121 : by measuring the temperature
• CPC Class Codes: B29C 66/91212 : involving measurement means being part of the welding jaws, e.g. integrated in the welding jaws
• CPC Class Codes: B29C 66/91231 : of the joining tool
• CPC Class Codes: B29C 66/91313 : by measuring the voltage, i.e. the electric potential difference or electric tension
• CPC Class Codes: B29C 66/91315 : by measuring the current intensity
• CPC Class Codes: B29C 66/9141 : by controlling or regulating the temperature
• CPC Class Codes: B29C 66/91421 : of the joining tools
• CPC Class Codes: B29C 66/91431 : the temperature being kept constant over time
• CPC Class Codes: B29C 66/91651 : by controlling or regulating the heat generated by Joule heating or induction heating
• CPC Class Codes: B29C 66/91653 : by controlling or regulating the voltage, i.e. the electric potential difference or electric tension
• CPC Class Codes: B29C 66/91655 : by controlling or regulating the current intensity
• CPC Class Codes: B29C 66/91921 : in explicit relation to another temperature, e.g. to the softening temperature or softening point, to the thermal degradation temperature or to the ambient temperature
• CPC Class Codes: B29C 66/961 : involving a feedback loop mechanism, e.g. comparison with a desired value
• CPC Class Codes: B29K 2827/18 : PTFE, i.e. polytetrafluorethene, e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2913/02 : coated
• CPC Class Codes: B29L 2031/108 : Roofs
• CPC Class Codes: E04D 15/04 : for roof coverings comprising slabs, sheets or flexible material
• CPC Class Codes: H05B 6/06 : Control, e.g. of temperature, of power
• CPC Class Codes: H05B 6/105 : using a susceptor
• CPC Class Codes: H05B 6/106 : in the form of fillings
• CPC Class Codes: H05B 6/14 : Tools, e.g. nozzles, rollers, calenders

Abstract

An induction heater having an induction coil (26) for heating a metallic substance (4) hidden by a membrane (2), the metallic substance being coated with a heat activated adhesive on its side adjacent the membrane (2). The heater having four location sensor coils (36) for detecting the position of the hidden metallic substance and means to facilitate the placement of the induction coil (26) over the hidden metallic substance (4), based on information from the sensors. Once the induction coil (26) is over the metallic substance (4) it is used to heat the adhesive thereby adhering the metallic substance (4) to the membrane (2). The sensors (36) are adjacent the inductor coil (26) and are insulated therefrom by an air gap (38).

Claims

1. An induction heater assembly for heating a metallic substance hidden beneath a sheet of material, said induction heater assembly comprising:

an induction coil for remotely heating said metallic substance through said sheet of material;

a sensor device for detecting a hidden location of said metallic substance beneath said sheet of material;

a visual indicator device; and

a control device coupled to said sensor device and said visual indicator device for receiving an output from said sensor device and controlling said visual indicator device responsive to said sensor device output to indicate a direction in which the induction heater assembly must be moved to facilitate placement of said induction coil over said metallic substance.

2. The induction heater of claim 1 wherein said sensor device comprises a four quadrant metal detector having four sensing coils.

3. The induction heater of claim 2 wherein said visual indicator device comprises four outer lights aligned in symmetrically opposed relation along two orthogonal center lines, and a fifth center light positioned at the central intersection of said center lines, said visual indicator device being operative wherein said four outer lights are selectively illuminated responsive to output from said sensing coils to indicate direction of movement of the induction heater assembly, said center light being selectively illuminated when said induction coil is aligned over said metallic substrate.

4. The induction heater of claim 2 wherein said sensing coils are respectively placed in symmetrically opposed relation along two orthogonal center lines that pass through a vertical axis of the induction coil, said sensing coils having sensing poles positioned within a plane extending through a lower face of said induction coil.

5. The induction heater of claim 4 wherein said induction coil and said sensing coils are imbedded within an insulating body, said insulating body having air gaps formed therein between said inductor coil and each of said sensing coils.

6. The induction heater of claim 4 wherein said sensor device further comprises a first frequency generator for a generating a first frequency signal through said induction coil, and second frequency generator for generating a second frequency signal through said sensing coils, said second frequency being lower than said first frequency, said magnetic fields generated by said sensing coils interacting with said magnetic field generated by said induction coil to provide an output signal.

7. The induction heater of claim 6 wherein said sensor device outputs voltage signals proportional to a sensing distance of said metallic substance from each of said sensing coils.

8. The induction heater of claim 7 wherein said control device subtracts the voltage signals of opposed pairs of sensors to compensate for temperature fluctuations.

9. The induction heater of claim 8 wherein said visual indicator device comprises four outer lights aligned in symmetrically opposed relation along two orthogonal center lines, and a fifth center light positioned at the central intersection of said center lines, said visual indicator device being operative wherein said four outer lights are selectively illuminated responsive to said voltage signals from said sensing coils to indicate direction of movement of the induction heater assembly, said center light being selectively illuminated when the subtracted voltage signal values of said pairs of sensing coils are substantially equal to zero.

10. The induction heater of claim 7 wherein said control device including means for disconnecting the first frequency generator from said induction coil during operation of a heat cycle.

11. The induction heater of claim 1 further comprising an audible indicator device.

12. The induction heater of claim 1 wherein said induction coil and said sensor device are mounted within a unitary housing, said housing including insulation disposed between said induction coil and said sensor device to reduce the flow of heat from the induction coil to said sensor device.

13. The induction heater of claim 1 further comprising an inductor coil cooling device.

14. The induction heater of claim 13 wherein said inductor coil comprises a tube having a path for the flow of a cooling fluid, said inductor coil cooling device comprising a cooling fluid within said inductor coil, and a circulating device for circulating said cooling fluid within said inductor coil.

15. The induction heater of claim 14 wherein said cooling device further comprises a heat exchanger in fluid communication with said inductor coil.