JPH0375043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for measuring the gap between a rotor blade and a casing of a turbine, an axial flow compressor for a jet engine, or the like.

BACKGROUND OF THE INVENTION When the gap between the rotor blades and the casing of a turbine is large, the performance and efficiency of the blade row generally decreases. As turbines become more efficient and performant, the gap between the rotor blades and the casing is shrinking, and at the same time the need to measure this gap has arisen.

As shown in Fig. 4, in the conventional method, in order to measure the gap between the rotor blade 1 and the casing 3,
I drilled a hole in a part of it and attached sensor 4.

Problems to be Solved by the Invention In the conventional method shown in FIG. 4, the irregularities on the surface of the rotor blade 1 can be measured, but the shape of the inner diameter of the casing 3 cannot be measured. It does not mean that the measurement was made over the circumference, but rather the casing 3 and rotor blade 1 where the sensor 4 was attached.
It merely measures the gap between the two. Generally, in turbines and axial flow compressors, in order to minimize the gap between the casing 3 and the rotor blades 1, seal fins 5 with a thickness of several mm are arranged along the inner diameter of the casing 3 (Fig. 5). It is necessary to measure the gap between the blade 1 and the seal fin 5. In particular, since the efficiency of the turbine changes depending on the degree of wear of the seal fin 5, it is necessary to measure the shape of the seal fin 5 along its inner diameter. However, the uneven state of the seal fin 5 cannot be measured by the conventional method of drilling a hole in a part of the casing 3 and attaching the sensor 4 thereto.

Means for Solving the Problem By attaching a sensor to the rotor blade side of a turbine or the like, wear of the seal fin can be detected over the entire circumference.

Operation: By measuring the inner diameter of the casing 3 and seal fin 5 of the turbine, the gap between the rotor blade 1 and the casing 3, or between the rotor blade 1 and the seal fin 5 is evaluated, and a decrease in efficiency of the turbine is detected.

Example As shown in Fig. 1, this device measures the gap between a shroud 6 placed at the tip of a rotor blade 1 of a turbine and a seal fin 5 placed along the inner diameter of a casing. be. This device can be roughly divided into three parts: a detection section, a signal processing section, and a sampling timing pulse generation section.
As shown in FIG. 2, the components include a detection end 11 attached to the side surface of the shroud 6 as a detection part so that the detection surface is parallel to the seal fin 5.
An optical fiber 10 is connected to the detection end 11. Further, a light emitter 12 is provided on the opposite side of the detection end 11 across the seal fin 5. Inside the detection end 11, a reflecting mirror 13 is attached at an angle of 45° to the upper surface of the shroud 6, as shown in FIG. The optical fibers 10 have single wires 14 of optical fibers arranged in a row in a direction perpendicular to a bright and dark band formed when the light from a light emitter 12 is blocked by a shroud 6 and a seal fin 5. The signal processing section includes a signal converter 7 that converts light into an electrical signal and a recorder 21. The sampling timing pulse generator includes a pulse generator 22 and a pulse counter 20 that are mechanically attached to the rotating shaft 23 of the turbine.

The length of the gap between the shroud 6 and the seal fin 5 is measured every time the rotation angle of the turbine shaft 23 shown in FIG. 2 rotates by a predetermined angle.

The pulse generator 22 outputs pulses to the pulse counter 20 in accordance with the rotation angle of the turbine shaft 23. When the predetermined number of pulses is counted by the pulse counter 20, a sampling timing pulse is output from the pulse counter 20 to the signal converter 7. At this time, the signal converter 7 converts the image of the optical fiber 10 into an electrical signal and transmits it to the recorder 21, and the recorder 21 records this signal as the length of the gap between the shroud 6 and the seal fin 5.

The detection machine detects the brightness and darkness created when the light emitted from the light emitting device 12 on the opposite side of the detection end 11 and the seal fin 5 toward the detection end 11 is blocked by the seal fin 5 and the shroud 6. The optical fiber 10 captures the light through a reflecting mirror 13 as shown in FIG. Inside the optical fiber 10, single wires 14 are arranged perpendicularly to the bright and dark bands, so that the bright part of the optical fiber 10 corresponds to the length of the gap between the seal fin 5 and the shroud 6.

Effects of the Invention By attaching a sensor to the rotor blade side, the degree of wear of the seal fin can be measured over the entire circumference.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the installation state of an embodiment of the micro gap measuring device of the present invention, Fig. 2 is a system diagram showing the overall configuration of the device shown in Fig. 1, and Fig. 3 is a schematic diagram of the detection section of the device shown in Fig. 1. Figures 4 and 4 are drawings showing how the conventional device is installed, and Figure 5 is a schematic cross-sectional view showing the seal fin attachment portion. 1... Moving blade, 3... Casing, 5... Seal fin, 6... Shroud, 10... Optical fiber, 11
...Detection end.

Claims (1)

[Claims] 1. In a seal fin provided on the inner surface of a casing close to the outer periphery of a shroud attached to a rotor blade, a light emitter and a detection end are attached to the rotor blade with the inner periphery of the seal fin interposed therebetween, and the detection end is mounted on the rotor blade. , consisting of a reflecting mirror that is inclined at 45 degrees with respect to the turbine axis and receives the light from the light emitter, and optical fibers that are arranged in a row in the turbine axis direction and receives the light from the reflecting mirror, and the radius of the inner circumference of the seal fin is 1. A seal fin wear measuring device, characterized in that the position of the seal fin is measured by an array of optical fibers arranged in the axial direction.