Method of controlling the induction heating of an elongated workpiece

Claim 1

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power supply, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. sensing the instantaneous power applied to said coil; b. creating a first signal representative of said sensed instantaneous power; c. sensing the instantaneous scanning velocity of said coil with respect to said workpiece; d. creating a second signal representative of said sensed instantaneous scanning velocity; e. combining said first and second signals to produce a third signal representative of the instantaneous energy distribution; f. providing a known energy distribution signal level profile for longitudinal displacement from said starting point to said ending point; g. sensing the displacement of said coil from said starting point; h. creating a fourth signal representative of said sensed dIsplacement; i. selecting an instantaneous portion of said distribution signal level profile corresponding to said fourth signal; j. comparing said third signal with said portion of said distribution signal level profile to produce a differential signal representative of the difference between said third signal and said portion of said profile; and, k. adjusting said power of said power supply in accordance with said differential signal.

Claim 2

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power supply, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. sensing the instantaneous power applied to said coil; b. creating a first signal representative of said sensed instantaneous power; c. sensing the instantaneous scanning velocity of said coil with respect to said workpiece; d. creating a second signal representative of said sensed instantaneous scanning velocity; e. combining said first and second signals to produce a third signal representative of the instantaneous energy distribution; f. providing a known energy distribution signal level profile for longitudinal displacement from said starting point to said ending point; g. sensing the displacement of said coil from said starting point; h. creating a fourth signal representative of said sensed dIsplacement; i. selecting an instantaneous portion of said distribution signal level profile corresponding to said fourth signal; j. comparing said third signal with said portion of said distribution signal level profile to produce a differential signal representative of the difference between said third signal and said portion of said profile; and, k. adjusting said power of said power supply in accordance with said differential signal.

Claim 5

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power supply, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. sensing the instantaneous power applied to said coil; b. creating a first signal representative of said sensed instantaneous power; c. sensing the instantaneous scanning velocity of said coil with respect to said workpiece; d. creating a second signal representative of said sensed instantaneous scanning velocity; e. combining said first and second signals to produce a third signal representative of the instantaneous energy distribution; f. providing a known energy distribution signal level profile for longitudinal displacement from said starting point to said ending point; g. sensing the displacement of said coil from said starting point; h. creating a fourth signal representative of said sensed displacement; i. selecting an instantaneous portion of said distributuion signal level profile corresponding to said fourth signal; j. comparing said third signal with said portion of said distribution signal level profile to produce a differential signal representative of the difference between said third signal and said portion of said profile; and, k. adjusting said scanning velocity of said coil in accordance with said differential signal.

Claim 6

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power supply, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. sensing the instantaneous power applied to said coil; b. creating a first signal representative of said sensed instantaneous power; c. sensing the instantaneous scanning velocity of said coil with respect to said workpiece; d. creating a second signal representative of said sensed instantaneous scanning velocity; e. combining said first and second signals to produce a third signal representative of the instantaneous energy distribution; f. providing a known energy distribution signal level profile for longitudinal displacement from said starting point to said ending point; g. sensing the displacement of said coil from said starting point; h. creating a fourth signal representative of said sensed displacement; i. selecting an instantaneous portion of said distributuion signal level profile corresponding to said fourth signal; j. comparing said third signal with said portion of said distribution signal level profile to produce a differential signal representative of the difference between said third signal and said portion of said profile; and, k. adjusting said scanning velocity of said coil in accordance with said differential signal.

Claim 8

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power supply, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. scanning said coil along said workpiece between said starting point and said ending point; b. creating a first signal representative of the instantaneous power being created by said coil during said scanning step; c. creating a second signal representative of the instantaneous velocity during said scanning step; d. combining the first signal and the second signal into a power-velocity signal as said coil scans said workpiece between said starting point and said ending point; e. simultaneously comparing said power-velocity signal with a desired power-velocity signal for each position along said workpiece and during said scanning step; and, f. adjusting said power of said power supply in accordance with said comparison during said scanning step.

Claim 9

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power supply, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. scanning said coil along said workpiece between said starting point and said ending point; b. creating a first signal representative of the instantaneous power being created by said coil during said scanning step; c. creating a second signal representative of the instantaneous velocity during said scanning step; d. combining the first signal and the second signal into a power-velocity signal as said coil scans said workpiece between said starting point and said ending point; e. simultaneously comparing said power-velocity signal with a desired power-velocity signal for each position along said workpiece and during said scanning step; and, f. adjusting said power of said power supply in accordance with said comparison during said scanning step.

Claim 10

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power suppLy, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. scanning said coil along said workpiece between said starting point and said ending point; b. creating a first signal representative of the instantaneous power being created by said coil during said scanning step; c. creating a second signal representative of the instantaneous velocity during said scanning step; d. combining the first signal and the second signal into a power-velocity signal as said coil scans said workpiece between said starting point and said ending point; e. simultaneously comparing said power-velocity signal with a desired power-velocity signal for each position along said workpiece and during said scanning step; and, f. adjusting said scanning velocity of said coil in accordance with said comparison during said scanning step.

Claim 11

A method of controlling the heating of an elongated, rotating workpiece between a starting point and an ending point on said workpiece, said workpiece being heated by an induction heating coil surrounding the workpiece and energized by a controllable power suppLy, as said coil scans along said workpiece at a scanning velocity, said method comprising the steps of: a. scanning said coil along said workpiece between said starting point and said ending point; b. creating a first signal representative of the instantaneous power being created by said coil during said scanning step; c. creating a second signal representative of the instantaneous velocity during said scanning step; d. combining the first signal and the second signal into a power-velocity signal as said coil scans said workpiece between said starting point and said ending point; e. simultaneously comparing said power-velocity signal with a desired power-velocity signal for each position along said workpiece and during said scanning step; and, f. adjusting said scanning velocity of said coil in accordance with said comparison during said scanning step.