JPH0523014U - Blade turbine shroud clearance determination device for steam turbine - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to measure even gap values of less than 3/100 mm, and it is possible to easily and reliably determine whether the gap is suitable or not.
This eliminates inconveniences such as a measurement difference caused by a human inspection. A laser projector 1 is provided with a projector 3 arranged to face a gap C between shrouds 11 of a steam turbine rotor blade 10.
The laser light from the laser diode 2 (connected to the power supply device 4 for supplying the oscillation power) is emitted from the light projector 3 as the light projection A. The reflected light B is received by the photodiode 6 of the laser detection device 5 and is regarded as an electromotive force. The presence of the gap is grasped and whether the gap value is suitable or not is determined by displaying the numerical value or the like on the display unit 8.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a blade shroud clearance determination device for a steam turbine, which measures a clearance value between shrouds provided on the outer diameter side of a moving blade of a steam turbine and determines whether the clearance value is appropriate or not.

[0002]

[Prior Art]

 Generally, on the outer diameter side of the moving blades of a steam turbine, the clearance between the blades is properly maintained, the rotating blades are prevented from flying out by centrifugal force, and the natural frequency is increased to increase the seismic strength. A shroud is attached to the.

As this shroud, for example, a plurality of moving blades are set as a set, and after being attached through a projection (referred to as Tenon) having a circular or rectangular cross section provided at the top of the moving blades, There are those that are caulked and combined, and those that have been machined together with the rotor blade and have the tenon omitted, such as integral shroud blades.

In such a shroud, the gap formed between the shrouds adjacent to each other is extremely important in terms of strength, and even if it is too large or too small, it has some influence on the blade to cause blade damage or the like. Cause an accident. Conventionally, it is common for an inspector to measure a gap between such important shrouds by inserting a skim gauge into the gap.

[0005]

[Problems to be solved by the device]

 However, in the inspection using such a skim gauge, it is possible to detect when the gap value is 3/100 mm or more, but when it is less than 3/100 mm, it is not possible to measure it by human hands and it is not possible to collect records. .. Therefore, conventionally, if the gap is less than 3/100 mm, it cannot be quantitatively grasped, and it cannot be judged whether the gap is suitable or not. In addition, since it is a human inspection, there is a problem of lack of reliability due to measurement differences between inspectors.

The present invention has been made in order to solve the problems of the prior art, and can measure a gap value of less than 3/100 mm, and it is easy and reliable to determine whether the gap is suitable or not. A blade turbine shroud clearance determination device for steam turbines that can improve the reliability of measurement values and contribute to the improvement of turbine quality by eliminating inconveniences such as measurement differences due to human inspection. The purpose is to do.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a blade shroud clearance determination device for a steam turbine according to the present invention is a laser oscillator that irradiates laser light to the clearance between shrouds provided on the outer diameter side of a moving blade of a steam turbine. And a laser detecting device for receiving reflected light or passing light from the shroud, the laser detecting device converting the received light amount into electric power and displaying the gap value between the shrouds, and A lamp determination unit that lamp-displays whether the detected gap value is suitable or not corresponding to the set value.

[0008]

[Action]

 Laser light has a high frequency and can be used to magnify small reflection effects and other measurements, and also has a short wavelength for extremely high resolution measurement, and its wavelength is in the visible light range.

Therefore, as in the above means, a laser oscillator such as a laser diode projects laser light into the gap between the shrouds, and a laser detector such as a photodiode detects reflected light or light passing through the gap. If it is detected as an electromotive force by receiving light, for example, when the value is above the preset value set for the photodiode, the lamp in the judgment unit is turned on to detect the existence of the gap and determine whether the gap value is appropriate or not. Can be determined.

Therefore, with such a means, it becomes possible to measure a gap of less than 3/100 mm, which could not be quantitatively measured in the past, by using laser light, and it is possible to easily determine the suitability of the gap. .. In addition, it is possible to eliminate problems such as measurement differences among inspectors due to human inspection, further improve the reliability of measured values, and contribute to the improvement of turbine quality. The size of the gap can be determined by changing the set value.

[0011]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. In this embodiment, a laser oscillating device 1 for irradiating a laser beam is composed of a laser diode (semiconductor laser oscillator) 2 for oscillating a thin laser beam having a single-color coherent and strong power, and the laser diode 2. The projector 3 is connected to the projector 3. The laser diode 2 is connected to a power supply device 4 and receives power for oscillation from the power supply device 4. The projector 3 also has a light receiving function of receiving the reflected light B of the projected light A from itself, and the reflected light B enters the laser detection device 5.

This laser detection device 5 has a photodiode (semiconductor diode detector) 6 for converting the amount of received light into electric power, and a display 7 connected to this photodiode 6, and the display 7 is A calculation unit that calculates the gap value between the shrouds according to the detected power, a display unit 8 that displays the gap value, and a lamp determination unit that lamp-displays whether the detected gap value corresponds to the set value or not. 9 and 9. The judgment value of the size of the gap to be measured can be adjusted by changing the set value of the photodiode 6.

When measuring the clearance C between the shrouds 11 of the steam turbine rotor blade 10, as shown in FIG. 1, the projector 3 is arranged so as to face the clearance C, and the projection A is emitted. The reflected light B is incident on the photodiode 6. Laser light has a high frequency and can be used to magnify small reflection effects and other measurements. It also has a short wavelength and enables measurement with extremely high resolution, and the wavelength is in the visible light range.

According to this embodiment, the laser diode 2 emits the laser light projection A through the projector 3 to the gap C between the shrouds 11, and the photodiode 6 receives the reflected light B to generate an electromotive force. Therefore, when the value is equal to or more than the set value set in the photodiode 6, the lamp of the lamp determination unit 9 is turned on, and the numerical value is displayed on the display unit 8 to display the gap. It becomes possible to grasp the existence of the and the appropriateness of the space value.

Therefore, it becomes possible to measure the gap of less than 3/100 mm, which could not be quantitatively measured in the past, by using the laser beam, and the suitability of the gap can be easily determined. In addition, it is possible to eliminate problems such as differences in measurement by inspectors due to human inspection, further improve reliability of measurement values, and contribute to improvement of turbine quality.

In the above embodiment, the reflected light is detected, but the passing light may be detected.

[0017]

[Effect of the device]

 As described above, according to the present invention, it becomes possible to measure a gap of less than 3/100 mm, which could not be quantitatively measured in the past, by using laser light, and it becomes possible to easily determine the suitability of the gap. Moreover, it is possible to eliminate defects such as measurement differences among inspectors due to human inspection, further improve the reliability of measurement values, and contribute to the improvement of turbine quality. ..

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a blade shroud clearance determining device for a steam turbine according to an embodiment of the present invention.

[Explanation of Codes] 1 laser oscillation device 2 laser diode 3 light projector 4 power supply device 5 laser detection device 6 photo diode 7 display device 8 display unit 9 lamp determination unit 10 steam turbine blade 11 shroud A light projection B reflected light C gap

Claims (1)

[Scope of utility model registration request] 1. A laser oscillating device for irradiating a gap between shrouds provided on the outer diameter side of a moving blade of a steam turbine with laser light, and a laser detecting device for receiving reflected light or passing light from the shroud. The laser detecting device converts an amount of received light into electric power to display a gap value between the shrouds, and a lamp determination for indicating whether or not the detected gap value corresponds to a set value by a lamp. And a blade shroud clearance determining device for a steam turbine.