High-frequency hardening apparatus

Patent metadata

Field	Value
Publication number	US-12200846-B2
Application number	US-202017433325-A
Country	US
Kind code	B2
Filing date	Jun 26, 2020
Priority date	Aug 28, 2019
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

This high-frequency hardening apparatus is provided with: an induction heating coil which has a U-shaped part that sandwiches a turbine blade, a pair of linear parts, and a connection part connecting the U-shaped part and the linear parts; a temperature detection unit which detects, in a non-contact manner, temperature around the induction heating coil; a moving mechanism which relatively moves the turbine blade and the induction heating coil in the direction of blade height; an electrical current supply unit which supplies a high-frequency electrical current to the induction heating coil; and a control device which has an electrical current control unit that, on the basis of a detection value provided by the temperature detection unit, controls the magnitude of the high-frequency electrical current supplied from the electrical current supply unit such that the detection value will not exceed a predetermined temperature.

First claim

The invention claimed is:

1. A high-frequency hardening apparatus comprising:
an induction heating coil that includes a U-shaped portion that sandwiches a leading edge of a turbine blade, a pair of linear portions that sandwiches the turbine blade, and a connecting portion that connects the U-shaped portion and the linear portions to each other on a convex side and a concave side of the turbine blade;
a temperature detection unit that detects a temperature in a first range of the leading edge of the turbine blade in a vicinity of the induction heating coil in a non-contact manner;
a moving mechanism that moves the turbine blade and the induction heating coil relative to each other in a blade height direction of the turbine blade;
an electrical current supply unit that supplies a high-frequency electrical current to the induction heating coil;
a control device that includes an electrical current controller, the electrical current controller controlling a magnitude of the high-frequency electrical current from the electrical current supply unit based on a detection value of the temperature detection unit such that the detection value does not exceed a predetermined temperature; and
an alarm temperature detection unit that is provided separately from the temperature detection unit and that detects a temperature distribution in a second range, the second range including the first range in which the temperature detection unit detects the temperature of the leading edge, the second range being wider than the first range,
wherein the electrical current controller is configured to issue an alarm in a case where the temperature distribution detected by the alarm temperature detection unit includes a value higher than a predetermined alarm threshold value.

2. The high-frequency hardening apparatus according to claim 1 ,
wherein the temperature detection unit detects a temperature of a portion of the leading edge that is on the convex side of the turbine blade and that is surrounded by the U-shaped portion and the linear portion.

3. The high-frequency hardening apparatus according to claim 1 ,
wherein the turbine blade is twisted in a circumferential direction around the blade height direction from one side toward the other side in the blade height direction, and
the high-frequency hardening apparatus further comprises a rotating mechanism that maintains a relative distance between the leading edge and the induction heating coil by rotating the turbine blade around a rotation axis extending in the blade height direction as the turbine blade and the induction heating coil move relative to each other in the blade height direction.

4. The high-frequency hardening apparatus according to claim 1 ,
wherein the temperature detection unit is an optical fiber type radiation temperature sensor.

5. The high-frequency hardening apparatus according to claim 1 ,
wherein the turbine blade includes a black coating film that is formed at least on the leading edge and that is formed of a black paint, and
the temperature detection unit is configured to detect a temperature of a surface of the black coating film.

6. The high-frequency hardening apparatus according to claim 1 ,
wherein the linear portion extends along a surface of the turbine blade to be parallel with the U-shaped portion.

7. The high-frequency hardening apparatus according to claim 1 ,
wherein the U-shaped portion is configured to sandwich the turbine blade by one-third of a distance from the leading edge in a chord direction of the turbine blade.

8. The high-frequency hardening apparatus according to claim 1 ,
wherein the moving mechanism includes a rail extending in the blade height direction, a first moving portion that is movable along the rail and extends upward from the rail, and a second moving portion supported so as to be movable in a vertical direction along the first moving portion.

9. The high-frequency hardening apparatus according to claim 8 ,
wherein the induction heating coil is supported by the second moving portion.

10. The high-frequency hardening apparatus according to claim 9 ,
wherein the temperature detection unit is fixed with respect to second moving portion directly or via a supporting part, and
the temperature detection unit is movable relative to the turbine blade together with the induction heating coil.

Assignees

• Mitsubishi Power Ltd
• Mitsubishi Heavy Ind Ltd

Inventors

• Asai Kunio
• Shishime Keiko
• Ishizawa Shuichi
• Kudo Takeshi
• Nagai Yurika
• Tanaka Katsumi

Classifications

• H05B6/102 Primary

  the metal pieces being rotated while induction heated · CPC title

• C21D9/0068

  for particular articles not mentioned below · CPC title

• C21D1/10 Primary

  by electric induction · CPC title

• Y02P10/25

  Process efficiency · CPC title

• H05B6/06 Primary

  Control, e.g. of temperature, of power · CPC title