JP2934534B2 - High frequency local heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency local heating device suitable for heating a steam turbine blade at the time of tenon caulking.

[0002]

2. Description of the Related Art A steam turbine blade is fixed to a shroud by passing a tenon provided at a turbine blade end through a shroud to caulk the tenon. Because of this, tenon is heated at the time of caulking, and this heating is performed by heating with a combustible gas flame.

However, since 17-4PH steel is a precipitation hardening type and is sensitive to heating, strict temperature control is required. However, temperature control cannot be performed accurately by heating with a gas flame. Problems such as cracks are often generated in the tenon during caulking, so that a skilled worker is required for heating during caulking of the tenon.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above circumstances, and easily and appropriately heats an object to be heated made of a material sensitive to heating under strict temperature control. It is an object of the present invention to provide a high-frequency local heating device which can eliminate the need for skilled workers.

[0005]

For this purpose, the present invention provides a heating coil housed in an outer jacket and having an iron core inserted therein, and a thermocouple vertically passed through the center of the iron core and urged toward the tip. A spacer attached to the tip of the mantle, a high-frequency power supply connected to the heating coil, and a temperature controller connected to the thermocouple and controlling the output of the high-frequency power supply with a signal from the thermocouple. It is characterized by having.

[0006]

In the high-frequency local heating apparatus of the present invention, high-frequency induction heating is used as a heating source to accurately control heating conditions, and a thermocouple vertically passing through the center of a heating coil iron core is pressed against an object to be heated. Temperature measurement accurately,
Further, the distance between the heating coil and the object to be heated is made constant by the spacer to stabilize the heating condition.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the high-frequency local heating device of the present invention is applied to a heating device for Tenon when assembling a turbine blade will be described with reference to the drawings. FIG. 1 is a perspective view of the present device, and FIG. is there.

In the upper figure, a shroud 3 is externally fitted to a tenon 2 formed at the tip of a turbine blade 1. A heating coil 5 made of a water-cooled copper tube is housed inside a jacket 4 having a lower opening, which is a main body of the present heating device for locally heating the tenon 2, with its axis being vertically oriented. 2, is connected to a high-frequency power source 8 via a matching transformer 7 as shown in FIG. 2, and the matching transformer 7 performs impedance matching between the high-frequency power source 8 and the heating coil 5. An iron core 9 such as a silicon steel plate, a ferrite core, or a sendust core is inserted into the heating coil 5, and a thermocouple 10 for temperature measurement is vertically passed through a through hole formed in the center of the iron core 9. .

A support plate 11 is attached to a portion of the thermocouple 10 protruding from the jacket 4, and a spring 12 for pressing the thermocouple 10 against the Tenon 2 by pressing the support plate 11 downward includes a spring receiving bracket 13. Mounted on Further, as shown in FIG. 2, a temperature controller 14 is connected to the leading end of the thermocouple 10 so that a signal for detecting the temperature of the Tenon 2 and controlling the temperature to a predetermined temperature is sent to the high frequency power supply 8. . At the lower open end of the mantle 4,
A spacer 15 for fixing the distance between the heating coil 5 and the Tenon 2 is attached, and a heat insulating plate 16 for blocking radiant heat from the Tenon 2 is provided.

According to such an apparatus, since high-frequency power is supplied from the high-frequency power supply 8 to the heating coil 5 having the iron core 9 to perform induction heating, the tenon 2 can be locally heated. At this time, the temperature of the tenon 2 is constantly measured by the thermocouple 10, and the high-frequency power supply 8 is controlled by the temperature controller 14, so that the heating conditions can be accurately controlled. In addition, a thermocouple 10 is inserted into a through hole of the iron core 9 arranged in the heating coil 5.
Is inserted and is always pressed against the tenon 2 by the spring 12, so that the temperature of the tenon 2 can be measured accurately and stably. Further, since the spacer 15 is attached in order to keep the distance between the tenon 2 and the heating coil 5 constant, the conditions are constant and more accurate when a plurality of heatings are performed. Thus, according to such a device, since high-frequency induction heating by the heating coil 5 is used, inaccuracies in temperature control such as heating by a combustible gas flame are eliminated, and the heating coil 5 is merely applied to the tenon 2. There is no need for a skilled operator such as a gas operator because the operation is simple.

[0011]

In summary, according to the present invention, a heating coil housed in a jacket and having an iron core inserted therein, a thermocouple vertically passed through the center of the iron core and urged toward the distal end,
A spacer attached to the tip of the mantle, a high-frequency power supply connected to the heating coil, and a temperature controller connected to the thermocouple and controlling the output of the high-frequency power supply with a signal from the thermocouple. Thereby, the object to be heated, which is a material sensitive to heating, can be easily and appropriately heated under strict temperature control, and a high-frequency local heating device that does not require a skilled operator is obtained. It is extremely useful.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment in which the high-frequency local heating device of the present invention is applied to a heating device of Tenon when assembling a turbine blade.

FIG. 2 is a system diagram of a control unit in the same as above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine blade 2 Tenon 3 Shroud 4 Mantle 5 Heating coil 6 Coil terminal 7 Matching transformer 8 High frequency power supply 9 Iron core 10 Thermocouple 11 Support plate 12 Spring 13 Spring receiving bracket 14 Temperature regulator 15 Spacer 16 Heat insulation plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-103069 (JP, A) JP-A-64-48669 (JP, A) JP-A-58-179873 (JP, U) JP-A-63 8074 (JP, Y2) Jikken 31-1714 (JP, Y1) (58) Field surveyed (Int. Cl. ⁶ , DB name) H05B ⁶ /00-6/44

Claims (1)

(57) [Claims] 1. A heating coil housed in an outer jacket and having an iron core inserted therein, a thermocouple vertically passed through the center of the iron core and urged toward the tip, and attached to the tip of the outer jacket. A high-frequency local heating device, comprising: a spacer, a high-frequency power supply connected to the heating coil, and a temperature controller connected to the thermocouple and controlling an output of the high-frequency power supply with a signal from the thermocouple. .