INDUCTOR FOR INDUCTIVELY HEATING METAL WORKPIECES

• US 3,842,234 A
• Filed: 01/10/1974
• Issued: 10/15/1974
• Est. Priority Date: 01/10/1974
• Status: Expired due to Term

• Current Assignee: Richard F. Seyfried
• Original Assignee: Richard F. Seyfried
• Inventors: Seyfried, Richard F.
• Primary Examiner(s): Reynolds, Bruce A.
• Application Number:
  US05/432,142
• Time in Patent Office: 278 Days
• Field of Search: 219/10.79,10.77,10.75,6.5,10.57,10.41,10.13,10.67,10.73 266/4EI,5EI 336/155,160,165,75,77
• US Class Current: 219/673
• CPC Class Codes: H05B 6/102 the metal pieces being rotated while induction heated

Abstract

A single-shot type inductor is provided with arrangements for selectively varying the current concentration along portions of the opposed faces of the inductor facing a workpiece therebetween. The arrangements provide for a single inductor to be employed to inductively heat workpieces which are of different contour, or to inductively heat different axial lengths of workpieces.

Claims

1. An inductor for inductively heating a metal workpiece comprising, a tubular conductor including spaced apart generally parallel first and second conductor portions having corresponding opposite ends and at least one bridging conductor portion interconnecting corresponding ones of said opposite ends, each of said conductor portions being linear between said opposite ends, said conductor having terminal ends connectable across a source of alterNating current for energizing said conductor, said first and second conductor portions being spaced apart for a workpiece to be supported therebetween in magnetically coupled relationship therewith and having opposed conductor faces facing said workpiece, and means selectively operable to vary the current concentration in corresponding axially adjacent areas of said conductor faces of both said first and second conductor portions when said conductor is energized, said selectively operable means including electrically conductive generally planar plate means separate from said tubular conductor and having a length in the direction between said opposite ends equal to the lengths of one of said corresponding areas, said plate means being generally parallel to and overlying and spanning the space between said first and second conductor portions, and motor means to displace said plate means into and out of magnetically coupled relationship with respect to said first and second conductor portions.

2. An inductor for inductively heating a metal workpiece comprising, a tubular conductor including spaced apart generally parallel first and second conductor portions having corresponding opposite ends and at least one bridging conductor portion interconnecting corresponding ones of said opposite ends, said conductor having terminal ends connectable across a source of alternating current for energizing said conductor, said first and second conductor portions being spaced apart for a workpiece to be supported therebetween in magnetically coupled relationship therewith and having opposed conductor faces facing said workpiece, and means selectively operable to vary the current concentration in corresponding axially adjacent areas of said conductor faces of both said first and second conductor portions when said conductor is energized, said means selectively operable to vary the current concentration including electrically conductive means magnetically coupled with said first and second conductor portions, and means to vary the impedance of said conductive means.

3. The inductor according to claim 2, wherein said means to vary the impedance of said conductive means includes saturable core means and winding means therefor connectable across a source of direct current.

4. The inductor according to claim 2, wherein said conductive means is plate means overlying and spanning the space between said first and second conductor portions, and said core means overlies said plate means.

5. The inductor according to claim 2, wherein the cross section of said core means varies in the direction along said first and second conductor portions.

6. An inductor for inductively heating a metal workpiece comprising, a tubular conductor including spaced apart generally parallel first and second conductor portions having corresponding opposite ends and at least one bridging conductor portion interconnecting corresponding ones of said opposite ends, said conductor having terminal ends connectable across a source of alternating current for energizing said conductor, said first and second conductor portions being spaced apart for a workpiece to be supported therebetween in magnetically coupled relationship therewith and having opposed conductor faces facing said workpiece, and means selectively operable to vary the current concentration in corresponding axially adjacent areas of said conductor faces of both said first and second conductor portions when said conductor is energized, said means selectively operable to vary the current concentration including flux concentrating means of magnetic material on corresponding axial portions of said first and second conductor portions, and means to selectively eliminate the flux concentrating effect of said flux concentrating means.

7. An inductor for inductively heating a metal workpiece comprising, a tubular conductor including spaced apart generally parallel first and second conductor portions having corresponding opposite ends and at least one bridgIng conductor portion interconnecting corresponding ones of said opposite ends, said conductor having terminal ends connectable across a source of alternating current for energizing said conductor, said first and second conductor portions being spaced apart for a workpiece to be supported therebetween in magnetically coupled relationship therewith and having opposed conductor faces facing said workpiece, and means selectively operable to vary the current concentration in corresponding axially adjacent areas of said conductor faces of both said first and second conductor portions when said conductor is energized, said means selectively operable to vary the current concentration including flux concentrating means of magnetic material on corresponding axial portions of said first and second conductor portions, and means to eliminate the flux concentrating effect of said flux concentrating means, said means to eliminate the flux concentrating effect includes winding means on said flux concentrating means connectable across a source of direct current.

8. An inductor for inductively heating a metal workpiece comprising, a tubular conductor including spaced apart generally parallel first and second conductor portions having corresponding opposite ends and at least one bridging conductor portion interconnecting corresponding ones of said opposite ends, each of said conductor portions being linear between said opposite ends, said conductor having terminal ends connectable across a source of alternating current for energizing said conductor, said first and second conductor portions being spaced apart for a workpiece to be supported therebetween in magnetically coupled relationship therewith and having opposed conductor faces facing said workpiece, and means selectively operable to vary the current concentration in corresponding axially adjacent areas of said conductor faces of both said first and second conductor portions when said conductor is energized, said tubular conductor having opposed pairs of parallel spaced apart sidewalls, flux concentrating means on said first and second conductor portions between the opposite ends thereof, said flux concentrating means including U-shaped elements of magnetic material overlying the sidewalls of each of said first and second conductor portions other than the sidewalls defining said opposed conductor faces, said means selectively operable to vary the current concentration including plate means of electrically conductive material movable between first and second positions with respect to said flux concentrating means, said plate means in said first position being disposed generally perpendicular to said opposed conductor faces and in magnetically coupled relationship with respect to said first and second conductor portions, said plate means having a length in the direction between the opposite ends of said first and second conductor portions less than the lengths of said flux concentrating means, said plate means in said second position being disposed out of magnetically coupled relationship with respect to said first and second conductor portions, and means to move said plate means between said first and second positions.

9. An inductor for inductively heating a metal workpiece comprising, a tubular conductor including spaced apart generally parallel first and second conductor portions having corresponding opposite ends and at least one bridging conductor portion interconnecting corresponding ones of said opposite ends, said conductor having terminal ends connectable across a source of alternating current for energizing said conductor, said first and second conductor portions being spaced apart for a workpiece to be supported therebetween in magnetically coupled relationship therewith and having opposed conductor faces facing said workpiece, and means selectively operable to vary the current concentration in corresponding axially adjacent areas of said conductor faces of both said first and second conductor portions when said conductOr is energized, said tubular conductor having opposed pairs of parallel spaced apart sidewalls, flux concentrating means on said first and second conductor portions between the opposite ends thereof, said flux concentrating means including U-shaped elements of magnetic material overlying the sidewalls of each of said first and second conductor portions other than the sidewalls defining said opposed conductor faces, said means selectively operable to vary the current concentration including plate means of electrically conductive material generally perpendicular to said opposed conductor faces and supported in magnetically coupled relationship with respect to said first and second conductor portions, said plate means having a length in the direction between the opposite ends of said first and second conductor portions less than the lengths of said flux concentrating means, and said selectively operable means further including saturable core means on said plate means and winding means on said core means connectable across a source of direct current.

10. The inductor according to claim 9, wherein the core means has a cross section which varies in the direction between said opposite ends of said first and second conductor portions.

11. An inductor for inductively heating a metal workpiece comprising, a tubular conductor including spaced apart generally parallel first and second conductor portions having corresponding opposite ends and at least one bridging conductor portion interconnecting corresponding ones of said opposite ends, said conductor having terminal ends connectable across a source of alternating current for energizing said conductor, said first and second conductor portions being spaced apart for a workpiece to be supported therebetween in magnetically coupled relationship therewith and having opposed conductor faces facing said workpiece, and means selectively operable to vary the current concentration in corresponding axially adjacent areas of said conductor faces of both said first and second conductor portions when said conductor is energized, said tubular conductor having opposed pairs of parallel spaced apart sidewalls, flux concentrating means on said first and second conductor portions between the opposite ends thereof, said flux concentrating means including U-shaped elements of magnetic material overlying the sidewalls of each of said first and second conductor portions other than the sidewalls defining said opposed conductor faces, said means selectively operable to vary the current concentration including a corresponding portion of the U-shaped elements on each of said first and second conductor portions and winding means on said corresponding portions connectable to a source of direct current.

12. The inductor according to claim 11, wherein said U-shaped elements are a plurality of thin metal laminations, the ones of said laminations defining said corresponding portions of said U-shaped elements having legs extending from the bridging portion of the U and defining an opening therewith, said coil means including a winding about the one of said leg parallel to said bridging portion.