Flow passage structure inspection system for hydraulic machine

Abstract

To provide a flow passage structure inspection system for a hydraulic machine that can readily and immediately check if any failure is generated in a flow passage structure.SOLUTION: A flow passage structure inspection system for a hydraulic machine includes: at least one ultrasonic sensor for irradiating a flow passage structure with an ultrasonic wave and detecting a reflection wave of the ultrasonic wave; a control unit for controlling irradiation with an ultrasonic wave by the ultrasonic sensor and receiving an output signal from the ultrasonic sensor; and a display part for displaying an inspection result on the basis of the output signal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a flow path structure inspection system for a hydraulic machine. [Background technology]

[0002] In Francis turbines used for hydroelectric power generation, water is guided by stay vanes and guide vanes arranged in the internal flow passage and flows into the runner. The runner includes runner blades, which are rotated by the pressure of the water. A generator is connected to the runner via a main shaft, and the rotation of the runner rotates the generator to generate electricity.

[0003] Cavitation erosion can occur on some surfaces of runner blades. Cavitation erosion can also occur on stay vanes and guide vanes. In addition, sediment may be entrained in the water flowing into the turbine, causing wear on the stay vanes, guide vanes, and runner blades. Depending on the magnitude of the stress generated in the runner blades during operation, cracks may also occur inside the runner blades.

[0004] It is necessary to detect such abnormalities as cavitation erosion, wear, and cracks early and repair them promptly. For this reason, inspection work is carried out on the flow path structures located in the internal flow path of the water turbine.

[0005] Inspection of the flow channel structure is carried out by stopping the operation of the turbine and draining the water from the internal flow channel before inspectors can enter the internal flow channel. Because the surfaces that define the internal flow channel are metal, if the internal flow channel is not sufficiently dry, the inspection will be carried out on a wet metal surface, which poses the risk of falling. Furthermore, the larger the power plant, the longer it takes to drain the water and carry out the inspection. For this reason, inspection of the flow channel structure takes a lot of time, making it difficult to carry out inspections quickly. In this case, repairing any abnormalities also takes time. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-326645 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-28588 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the embodiment is to provide a flow path structure inspection system for hydraulic machinery that can easily and quickly check for the presence or absence of abnormalities occurring in the flow path structure. [Means for solving the problem]

[0008] A hydraulic machine flow path structure inspection system according to an embodiment is a system for inspecting a flow path structure arranged in an internal flow path through which water flows passing through a runner of the hydraulic machine. The flow path structure inspection system includes at least one ultrasonic sensor that irradiates the flow path structure with ultrasonic waves and detects reflected waves of the ultrasonic waves, a control unit that controls the irradiation of ultrasonic waves by the ultrasonic sensor and receives an output signal from the ultrasonic sensor, and a display unit that displays inspection results based on the output signal. [Effects of the Invention]

[0009] According to the embodiment, it is possible to easily and quickly check whether or not an abnormality has occurred in the flow path structure. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a meridional cross-sectional view for explaining the configuration of a hydraulic machine according to a first embodiment. [Figure 2] FIG. 2 is a meridian cross-sectional view for explaining a schematic configuration of the flow path structure inspection system according to the first embodiment. [Figure 3] FIG. 3 is a partial cross-sectional view showing an ultrasonic sensor disposed on the stay vane shown in FIG. [Figure 4] FIG. 4 is a meridian cross-sectional view for explaining a schematic configuration of a flow path structure inspection system according to the second embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a phased array ultrasonic sensor in a flow channel structure inspection system according to the third embodiment. [Figure 6] FIG. 6 is a meridian cross-sectional view for explaining a schematic configuration of a flow path structure inspection system according to the fourth embodiment. [Figure 7] FIG. 7 is a plan view of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a hydraulic machine flow path structure inspection system according to an embodiment of the present invention will be described with reference to the drawings.

[0012] First, a hydraulic machine according to this embodiment will be described with reference to Fig. 1. Here, a Francis pump-turbine, which is an example of a hydraulic machine, will be described with reference to Fig. 1. In the following description, the terms upstream and downstream are used in accordance with the flow of water when the turbine is operating.

[0013] As shown in Figure 1, a Francis pump-turbine 1 comprises a spiral casing 2 into which water flows from an upper reservoir through a penstock (none of which are shown) during turbine operation, a plurality of stay vanes 3, a plurality of guide vanes 4, a runner 5, and a draft pipe 6.

[0014] The stay vanes 3 are components that guide water that has flowed into the casing 2 to the guide vanes 4 and runner 5. The stay vanes 3 are arranged on the inner periphery of the casing 2. A number of stay vanes 3 are arranged at intervals around the runner 5, forming a fixed stationary blade row. A flow path through which water flows is formed between two circumferentially adjacent stay vanes 3. The upper and lower ends of the stay vanes 3 are supported by stay rings 7. The stay rings 7 are made up of components provided above and below the stay vanes 3, respectively.

[0015] The guide vanes 4 are components that guide the inflowing water into the runner 5. The guide vanes 4 are arranged on the inner circumferential side of the stay vanes 3. A plurality of guide vanes 4 are arranged at predetermined intervals in the circumferential direction, forming a movable stationary blade row. A flow path for water to flow is formed between two circumferentially adjacent guide vanes 4. Each guide vane 4 is rotatably supported by an upper cover 8 and a lower cover 9. By rotating each guide vane 4 to change the opening degree, the flow rate of water flowing into the runner 5 can be adjusted. In this way, the power generation amount of the generator, which will be described later, can be adjusted.

[0016] The runner 5 is configured to be rotatable around the rotation axis X relative to the casing 2. The runner 5 is rotationally driven by the water flowing in from the casing 2 when the turbine is operating. The runner 5 is a component that converts the pressure energy of the water flowing into the runner 5 into rotational energy to obtain power. The runner 5 is configured as a rotary impeller.

[0017] The runner 5 includes a crown 5a connected to the main shaft 10 (described later), a band 5b provided on the outer periphery of the crown 5a, and a plurality of runner blades 5c provided between the crown 5a and the band 5b. The plurality of runner blades 5c are arranged at predetermined intervals in the circumferential direction. A flow path through which water flows is formed between two circumferentially adjacent runner blades 5c.

[0018] A draft pipe 6 is provided downstream of the runner 5 when the turbine is in operation. The draft pipe 6 is connected to a lower pond (not shown), and the water that rotates the runner 5 recovers pressure and is released into the lower pond.

[0019] A main shaft 10 is connected to the crown 5a of the runner 5. The main shaft 10 is configured to be rotatable together with the runner 5 about a rotation axis X that extends in the vertical direction. The main shaft 10 extends along the rotation axis X.

[0020] A generator (not shown) is connected to the main shaft 10. When the turbine is operating, the generator generates electricity using the power of the runner 5. This provides an electrical output.

[0021] The Francis pump-turbine 1 according to this embodiment is capable of pumping operation as well as turbine operation. In this case, the generator also functions as an electric motor, and when supplied with electricity, it drives the runner 5 to rotate. In this case, the runner 5 rotates in the opposite direction to when the turbine is operating. This allows water in the lower reservoir to be sucked up through the draft pipe 6 and discharged into the upper reservoir through the casing 2. In this way, the Francis pump-turbine 1 is capable of pumping operation (pumping operation). In this case, the opening of the guide vanes 4 is adjusted to obtain an appropriate pumping amount according to the pump head.

[0022] The Francis pump-turbine 1 configured as above can be roughly divided into an internal flow path 11 through which water flows, a flow path structure 12 arranged in the internal flow path 11, and a flow path defining portion 13 that defines the internal flow path 11. The flow path defining portion 13 includes the casing 2, stay ring 7, upper cover 8, lower cover 9, and draft pipe 6 described above. Water flows through the internal flow path 11 defined by the flow path defining portion 13. The flow path structure 12 arranged in the internal flow path 11 includes the stay vanes 3, guide vanes 4, and runner blades 5c of the runner 5.

[0023] Next, a flow path structure inspection system for hydraulic machinery according to this embodiment (hereinafter simply referred to as flow path structure inspection system 20) will be described with reference to Figures 2 and 3. The flow path structure inspection system 20 is a system for inspecting a flow path structure 12 arranged in an internal flow path 11 through which water flows when passing through a runner 5.

[0024] The flow path structure inspection system 20 according to this embodiment includes a plurality of ultrasonic sensors, a control unit 30, a transmitting unit 31, a receiving unit 32, and a display unit 33.

[0025] The ultrasonic sensor is a sensor for irradiating the flow path structure 12 with ultrasonic waves and detecting the reflected waves of these ultrasonic waves. The ultrasonic sensor according to this embodiment irradiates ultrasonic waves from inside the flow path structure 12. The received reflected waves are output as an output signal to the control unit 30. The ultrasonic sensor according to this embodiment is controlled by the control unit 30, and irradiates ultrasonic waves based on instructions from the control unit 30.

[0026] As shown in FIG. 2, the multiple ultrasonic sensors according to this embodiment may include ultrasonic sensors 21A to 21D arranged on the runner 5, ultrasonic sensors 22A and 22B arranged on the guide vane 4, and ultrasonic sensors 23A to 23D arranged on the stay vane 3.

[0027] The ultrasonic sensor 21A may be disposed inside the runner vane 5c. The ultrasonic sensor 21A may be capable of emitting ultrasonic waves toward the end (inlet band side 5d) of the upstream edge of the runner vane 5c serving as the flow path structure 12, on the band 5b side. The inlet band side 5d is a portion where cavitation erosion or wear due to sediment inflow may occur. If erosion or wear progresses in the inlet band side 5d, a decrease in operating efficiency may become a problem. The ultrasonic sensor 21A may be capable of emitting ultrasonic waves from inside the runner vane 5c toward the inlet band side 5d.

[0028] The ultrasonic sensor 21A may be configured with a single oscillator (element). In this case, the ultrasonic sensor 21A may irradiate ultrasonic waves perpendicularly to the target. The target of irradiation by the ultrasonic sensor 21A may be the pressure surface (see symbol 5cP in FIG. 5) or the negative pressure surface (see symbol 5cN in FIG. 5) of the inlet band side portion 5d. In this case, the ultrasonic sensor 21A may irradiate ultrasonic waves perpendicularly to the pressure surface or the negative pressure surface. The runner blade 5c includes fillets formed on the end of the runner blade 5c on the crown 5a side and the end on the band 5b side, respectively, and the surfaces of the fillets are also included in the pressure surface and the negative pressure surface. Note that the direction of irradiation of ultrasonic waves by the ultrasonic sensor 21A is not limited to being perpendicular to the target surface. For example, depending on the configuration of the ultrasonic sensor 21A, the direction of irradiation of ultrasonic waves by the ultrasonic sensor 21A may be inclined with respect to the target surface. The same applies to other ultrasonic sensors described later.

[0029] Ultrasonic waves may be irradiated to a portion of the pressure surface or suction surface of the runner blade 5c where abnormalities such as cavitation erosion, wear, or cracks are likely to occur. As wear progresses in that portion, the response time it takes for the irradiated ultrasonic waves to reflect off the surface where cavitation erosion or wear has occurred and return changes, making it possible to detect the occurrence of cavitation erosion or wear. Alternatively, if a crack occurs inside the runner blade 5c, the occurrence of the crack can be detected by the change in the response time of the ultrasonic waves. The same applies to the other ultrasonic sensors described below.

[0030] The ultrasonic sensor 21A may be embedded inside the runner blade 5c. For example, the ultrasonic sensor 21A may be housed in a cavity (not shown) formed inside the runner blade 5c, or may be housed in a groove 40 (see FIG. 5) formed on the surface (pressure surface or negative pressure surface) of the runner blade 5c. When the ultrasonic sensor 21A is housed in the groove 40, the ultrasonic sensor 21A may be covered with a cover member 41 (see FIG. 5) so as not to be exposed on the surface of the runner blade 5c. Similarly, the signal wiring connected to the ultrasonic sensor 21A may be housed in a cavity, or may be housed in a groove and covered with a cover member. The same applies to the other ultrasonic sensors described below.

[0031] Two ultrasonic sensors 21A may be arranged on the runner blade 5c. One of the ultrasonic sensors 21A may be capable of emitting ultrasonic waves toward the pressure surface of the inlet band side portion 5d (see FIG. 5, which will be described later). The other ultrasonic sensor 21A may be capable of emitting ultrasonic waves toward the negative pressure surface of the inlet band side portion 5d. Furthermore, an ultrasonic sensor 21A may be arranged on each of the runner blades 5c.

[0032] The ultrasonic sensor 21B may be disposed inside the runner vane 5c. The ultrasonic sensor 21B may be capable of emitting ultrasonic waves toward the end (outlet crown side portion 5e) of the downstream edge of the runner vane 5c serving as the flow path structure 12, on the crown 5a side. The outlet crown side portion 5e is a portion that may be subject to cavitation erosion or wear due to sediment inflow, as well as cracks due to stress concentration. If cavitation erosion or wear progresses in the outlet crown side portion 5e, a decrease in operating efficiency may become a problem. The ultrasonic sensor 21B may be capable of emitting ultrasonic waves from inside the runner vane 5c toward the outlet crown side portion 5e.

[0033] Two ultrasonic sensors 21B may be arranged on the runner vane 5c. One ultrasonic sensor 21B may be capable of emitting ultrasonic waves toward the pressure surface of the outlet crown side portion 5e. The other ultrasonic sensor 21B may be capable of emitting ultrasonic waves toward the negative pressure surface of the outlet crown side portion 5e. Furthermore, an ultrasonic sensor 21B may be arranged on each runner vane 5c.

[0034] The ultrasonic sensor 21C may be disposed inside the runner vane 5c. The ultrasonic sensor 21C may be capable of emitting ultrasonic waves toward the end (outlet band side 5f) of the downstream edge of the runner vane 5c serving as the flow path structure 12, on the band 5b side. The outlet band side 5f is a portion where cracks due to stress concentration (see symbol C in FIG. 2) may occur in addition to wear due to cavitation erosion or sediment inflow. If cavitation erosion or wear progresses in the outlet band side 5f, a decrease in operating efficiency may become a problem. The ultrasonic sensor 21C may be capable of emitting ultrasonic waves from inside the runner vane 5c toward the outlet band side 5f.

[0035] Two ultrasonic sensors 21C may be arranged on the runner blade 5c. One of the ultrasonic sensors 21C may be capable of emitting ultrasonic waves toward the pressure surface of the outlet band side portion 5f (see FIG. 5, which will be described later). The other ultrasonic sensor 21C may be capable of emitting ultrasonic waves toward the negative pressure surface of the outlet band side portion 5f. Furthermore, an ultrasonic sensor 21C may be arranged on each of the runner blades 5c.

[0036] The ultrasonic sensor 21D may be disposed in the crown 5a of the runner 5. The crown 5a and the runner vanes 5c may be seamlessly formed as a single unit. The ultrasonic sensor 21D may be capable of emitting ultrasonic waves toward the end (central crown side portion 5g) of the runner vanes 5c, which are the flow path structure 12, located between the upstream and downstream edges and facing the crown 5a. The central crown side portion 5g is a portion where cavitation erosion or wear due to sediment inflow may occur. If cavitation erosion or wear progresses in the central crown side portion 5g, a decrease in operating efficiency may become a problem. The ultrasonic sensor 21D may be capable of emitting ultrasonic waves from inside the crown 5a toward the central crown side portion 5g of the runner vanes 5c.

[0037] Two ultrasonic sensors 21D may be disposed on the runner blade 5c. One ultrasonic sensor 21D may be capable of emitting ultrasonic waves toward the pressure surface of the central crown side portion 5g. The other ultrasonic sensor 21D may be capable of emitting ultrasonic waves toward the negative pressure surface of the central crown side portion 5g. Furthermore, the ultrasonic sensors 21D may be disposed at positions on the crown 5a where they can irradiate ultrasonic waves onto the central crown side portion 5g.

[0038] The ultrasonic sensors 21A-21D and the control unit 30 may be able to communicate with each other via a rotary connector 34 or wireless communication. In the example shown in FIG. 2, the ultrasonic sensors 21A-21D and the control unit 30 are able to communicate with each other via the rotary connector 34. Although not shown, the rotary connector 34 may include a rotation-side terminal attached to the runner 5 and a stationary-side terminal attached to a stationary member. The rotary connector 34 may include a plurality of rotation-side terminals and a plurality of stationary-side terminals, and the rotation-side terminal and stationary-side terminal corresponding to the ultrasonic sensors may be electrically connected. Each of the rotation-side terminals is connected to a corresponding ultrasonic sensor 21A-21D via a signal wiring. The control unit 30 is connected to each stationary-side terminal. The rotation-side terminal and the stationary-side terminal are configured to maintain electrical contact even during rotation of the runner 5. An example of the rotary connector 34 is a slip ring, but is not limited to this. When the ultrasonic sensors 21A-21D and the control unit 30 can communicate via wireless communication, a rotating-side antenna (not shown) that receives and transmits wireless radio waves may be attached to the runner 5. A stationary-side antenna that can communicate wirelessly with this rotating-side antenna may be connected to the control unit 30. The stationary-side antenna may be built into the control unit 30. As an example of wireless communication, underwater optical wireless communication may be used.

[0039] An ultrasonic sensor capable of emitting ultrasonic waves toward either the upper end or the lower end of the guide vane 4 may be disposed inside the guide vane 4 disposed upstream of the runner 5. In this embodiment, the guide vane 4 is provided with an ultrasonic sensor 22A and an ultrasonic sensor 22B.

[0040] The ultrasonic sensor 22A may be disposed inside the guide vane 4. The ultrasonic sensor 22A may be capable of emitting ultrasonic waves toward the upper end (upper end fillet 4a) of the guide vane 4 serving as the flow path structure 12. The upper end fillet 4a is the portion of the guide vane 4 that faces the upper cover 8, and is a portion where cavitation erosion or wear due to sediment inflow may occur. If cavitation erosion or wear progresses in the upper end fillet 4a, leakage flow rate may become a problem. The ultrasonic sensor 22A may be capable of emitting ultrasonic waves from inside the guide vane 4 toward the upper end fillet 4a.

[0041] Two ultrasonic sensors 22A may be disposed in the guide vane 4. One ultrasonic sensor 22A may be capable of emitting ultrasonic waves toward the pressure surface of the upper end fillet portion 4a. The other ultrasonic sensor 22A may be capable of emitting ultrasonic waves toward the negative pressure surface of the upper end fillet portion 4a. Furthermore, an ultrasonic sensor 22A may be disposed in each guide vane 4.

[0042] Ultrasonic sensor 22B may be disposed inside guide vane 4. Ultrasonic sensor 22B may be capable of emitting ultrasonic waves toward the lower end (lower end fillet 4b) of guide vane 4 serving as flow path structure 12. Lower end fillet 4b is the portion of guide vane 4 that faces lower cover 9 and is a portion where cavitation erosion or wear due to sediment inflow may occur. If cavitation erosion or wear progresses in lower end fillet 4b, leakage flow rate may become a problem. Ultrasonic sensor 22B may be capable of emitting ultrasonic waves from inside guide vane 4 toward lower end fillet 4b.

[0043] Two ultrasonic sensors 22B may be disposed in the guide vane 4. One ultrasonic sensor 22B may be capable of emitting ultrasonic waves toward the pressure surface of the lower end fillet portion 4b. The other ultrasonic sensor 22B may be capable of emitting ultrasonic waves toward the negative pressure surface of the lower end fillet portion 4b. Furthermore, an ultrasonic sensor 22B may be disposed in each guide vane 4.

[0044] An ultrasonic sensor capable of emitting ultrasonic waves toward either the upper end or the lower end of the upstream edge of the stay vane 3 may be disposed inside the stay vane 3 disposed upstream of the guide vane 4. In this embodiment, the stay vane 3 is provided with an ultrasonic sensor 23A and an ultrasonic sensor 23B.

[0045] The ultrasonic sensor 23A may be disposed inside the stay vane 3. The ultrasonic sensor 23A may be capable of emitting ultrasonic waves toward the upper end (inlet upper end root 3a) of the upstream edge of the stay vane 3 serving as the flow path structure 12. The inlet upper end root 3a is a portion where wear due to cavitation erosion or sediment inflow may occur. The ultrasonic sensor 23A may be capable of emitting ultrasonic waves from inside the stay vane 3 toward the inlet upper end root 3a in the direction from the downstream side to the upstream side.

[0046] Two ultrasonic sensors 23A may be arranged on the stay vane 3. One ultrasonic sensor 23A may be capable of emitting ultrasonic waves toward the pressure surface of the inlet upper end root portion 3a. The other ultrasonic sensor 23A may be capable of emitting ultrasonic waves toward the negative pressure surface of the inlet upper end root portion 3a. Furthermore, an ultrasonic sensor 23A may be arranged on each stay vane 3.

[0047] The ultrasonic sensor 23B may be disposed inside the stay vane 3. The ultrasonic sensor 23B may be capable of emitting ultrasonic waves toward the lower end (inlet lower end root 3b) of the upstream edge of the stay vane 3 serving as the flow path structure 12. The inlet lower end root 3b is a portion where wear due to cavitation erosion or sediment inflow may occur. The ultrasonic sensor 23B may be capable of emitting ultrasonic waves from inside the stay vane 3 toward the inlet lower end root 3b in the direction from the downstream side to the upstream side.

[0048] Two ultrasonic sensors 23B may be arranged on the stay vane 3. One of the ultrasonic sensors 23B may be capable of emitting ultrasonic waves toward the pressure surface of the inlet lower end root portion 3b. The other ultrasonic sensor 23B may be capable of emitting ultrasonic waves toward the negative pressure surface of the inlet lower end root portion 3b. Furthermore, an ultrasonic sensor 23B may be arranged on each stay vane 3.

[0049] The Francis pump-turbine 1 according to this embodiment is configured to be capable of pumping. In this case, as shown in Fig. 3, an ultrasonic sensor capable of emitting ultrasonic waves toward either the upper end or the lower end of the downstream edge of the stay vane 3 may be further disposed inside the stay vane 3. In this embodiment, ultrasonic sensors 23C and 23D are disposed in the stay vane 3.

[0050] Ultrasonic sensor 23C may be disposed inside stay vane 3. Ultrasonic sensor 23C may be capable of emitting ultrasonic waves toward the upper end (outlet upper end root 3c) of the downstream edge of stay vane 3. Outlet upper end root 3c is a portion where cavitation erosion or wear due to sediment inflow may occur during pump operation. Ultrasonic sensor 23C may be capable of emitting ultrasonic waves from inside stay vane 3 toward outlet upper end root 3c in a direction from the upstream side to the downstream side. Ultrasonic sensor 23C may be disposed in a different position from ultrasonic sensor 23A described above so as not to interfere with it.

[0051] Two ultrasonic sensors 23C may be arranged on the stay vane 3. One ultrasonic sensor 23C may be capable of emitting ultrasonic waves toward the pressure surface of the outlet upper end root portion 3c. The other ultrasonic sensor 23C may be capable of emitting ultrasonic waves toward the negative pressure surface of the outlet upper end root portion 3c. Furthermore, an ultrasonic sensor 23C may be arranged on each stay vane 3.

[0052] Ultrasonic sensor 23D may be disposed inside stay vane 3. Ultrasonic sensor 23D may be capable of emitting ultrasonic waves toward the lower end (outlet lower end root 3d) of the downstream edge of stay vane 3. Outlet lower end root 3d is a portion where cavitation erosion or wear due to sediment inflow may occur during pump operation. Ultrasonic sensor 23D may be capable of emitting ultrasonic waves from inside stay vane 3 toward outlet lower end root 3d in a direction from the upstream side to the downstream side. Ultrasonic sensor 23D may be disposed in a different position from ultrasonic sensor 23B described above so as not to interfere with it.

[0053] Two ultrasonic sensors 23D may be arranged on the stay vane 3. One ultrasonic sensor 23D may be capable of emitting ultrasonic waves toward the pressure surface of the outlet lower end root portion 3d. The other ultrasonic sensor 23D may be capable of emitting ultrasonic waves toward the negative pressure surface of the outlet lower end root portion 3d. Furthermore, an ultrasonic sensor 23D may be arranged on each stay vane 3.

[0054] The control unit 30 is configured to control the emission of ultrasonic waves by each of the ultrasonic sensors 21A-23D and to receive output signals from the ultrasonic sensors 21A-23D. The control unit 30 is capable of communicating with each of the ultrasonic sensors 21A-23D. More specifically, the control unit 30 is connected to the stationary terminal of the rotary connector 34 via signal wiring, enabling communication with the ultrasonic sensors 21A-21D. The control unit 30 is also connected to the ultrasonic sensors 22A, 22B, and 23A-23D via other signal wiring, enabling communication with the ultrasonic sensors 22A, 22B, and 23A-23D. The control unit 30 may arbitrarily adjust the timing at which the ultrasonic sensors 21A-21D, 22A, 22B, and 23A-23D emit ultrasonic waves. When an ultrasonic sensor receives a wave reflected from a surface or crack where cavitation erosion or wear has occurred, the ultrasonic sensor outputs an output signal and transmits it to the control unit 30.

[0055] The control unit 30 may include a calculation unit (not shown) that calculates the inspection results based on the output signals. The calculation unit may, for example, calculate the response time from when the ultrasonic sensor emits ultrasonic waves until the reflected waves return. The calculation unit may then compare the current response time with the response time calculated when the Francis pump-turbine 1 was new to calculate the response time difference. In this case, the calculation unit may calculate the response time difference for each of the ultrasonic sensors 21A-21D, 22A, 22B, and 23A-23D. The calculated response time difference may be transmitted to the display unit 33 as the inspection result. Alternatively, the depth of cavitation erosion or the amount of wear may be calculated based on the response time difference and transmitted to the display unit 33 as the inspection result.

[0056] The transmitting unit 31 is connected to the control unit 30. The transmitting unit 31 may be connected to the control unit 30 by wire or wirelessly. The transmitting unit 31 transmits the test results received from the control unit 30 to the receiving unit 32. The transmitting unit 31 is connected to the receiving unit 32 by wire or wirelessly. The transmitting unit 31 may be connected to the receiving unit 32 via the Internet.

[0057] The receiving unit 32 receives the test results transmitted from the transmitting unit 31 and transmits them to the display unit 33. The receiving unit 32 may be connected to the display unit 33 by wire or wirelessly.

[0058] The display unit 33 is configured to display the inspection results based on the output signals of the ultrasonic sensors transmitted from the control unit 30. The display unit 33 may display the inspection results in any manner. For example, as described above, the display unit 33 may display the inspection results calculated by the calculation unit of the control unit 30. Alternatively, the display unit 33 may display the waveform of the reflected waves detected by the ultrasonic sensors as the inspection results. An inspector may check the inspection results displayed on the display unit 33 and determine whether or not any abnormalities such as cavitation erosion, wear, or cracks have occurred. The display unit 33 may be installed at a location separate from the Francis pump-turbine 1.

[0059] The thus configured flow channel structure inspection system 20 according to this embodiment can inspect the flow channel structure 12 not only when the Francis pump-turbine 1 is out of operation, but also during operation. In this case, the effects of vibrations that occur during operation may be corrected. For example, when the Francis pump-turbine 1 is new, a correction amount may be calculated in advance by comparing inspection results obtained while the Francis pump-turbine 1 is out of operation with inspection results obtained during operation. This correction amount may be used to correct the inspection results obtained during the current operation.

[0060] As described above, according to this embodiment, at least one ultrasonic sensor irradiates ultrasonic waves into the inside of the flow path structure 12 and detects reflected waves of the ultrasonic waves, the control unit 30 receives output signals from the ultrasonic sensors, and the display unit 33 displays the inspection results based on the output signals. This makes it possible to detect the occurrence of abnormalities such as cavitation erosion, wear, or cracks in the flow path structure 12. This eliminates the need to stop the operation of the Francis pump-turbine 1 to inspect the flow path structure 12, and also eliminates the need to drain water from the internal flow path 11. As a result, the presence or absence of abnormalities in the flow path structure 12 can be easily and quickly confirmed. Furthermore, it is also possible to eliminate the need for inspectors to enter the internal flow path 11, ensuring the safety of the inspectors.

[0061] In the above-described embodiment, an example has been described in which the flow path structure inspection system 20 includes the ultrasonic sensors 21A to 21D, 22A, 22B, and 23A to 23D. However, the embodiment is not limited to this. The flow path structure inspection system 20 only needs to include at least one ultrasonic sensor from among the ultrasonic sensors 21A to 21D, 22A, 22B, and 23A to 23D.

[0062] (Second embodiment) Next, a hydraulic machine flow path structure inspection system according to a second embodiment will be described with reference to FIG.

[0063] The second embodiment shown in Figure 4 differs mainly in that an ultrasonic sensor arranged in a flow path defining portion that defines the internal flow path irradiates ultrasonic waves to either a guide vane or a stay vane arranged upstream of the runner, and other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 3. In Figure 4, the same parts as those in the first embodiment shown in Figures 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0064] 4, the flow path structure inspection system 20 according to this embodiment may include at least one ultrasonic sensor that is disposed in the flow path defining portion 13 that defines the internal flow path 11 and that irradiates ultrasonic waves onto either the guide vane 4 or the stay vane 3. In this embodiment, the flow path structure inspection system 20 includes an ultrasonic sensor 24A and an ultrasonic sensor 24B.

[0065] The ultrasonic sensor 24A may be disposed inside the rod 4c of the guide vane 4. The rod 4c is connected to a rotation drive unit (not shown), and the rod 4c and the guide vane 4 are formed seamlessly as a single unit. The ultrasonic sensor 24A may be capable of emitting ultrasonic waves toward the guide vane 4 serving as the flow path structure 12. This improves the accuracy of detecting cracks (see symbol C in FIG. 4 ) extending in the direction of water flow in the guide vane 4. The ultrasonic sensor 24A may be disposed above the guide vane 4 to be irradiated. The ultrasonic sensor 24A may be capable of irradiating ultrasonic waves from inside the rod 4c toward the guide vane 4 disposed below. Alternatively, the ultrasonic sensor 24A may be disposed inside the guide vane 4 and be capable of irradiating ultrasonic waves toward the upper or lower end of the guide vane 4. In this case, a joint formed by welding or the like may exist between the rod 4c and the guide vane 4. The ultrasonic sensor 24A may be connected to the control unit 30 via signal wiring. The ultrasonic sensors 24A may be disposed at positions where they can irradiate the corresponding guide vanes 4 with ultrasonic waves.

[0066] The ultrasonic sensor 24A may be configured to be able to scan the direction of ultrasonic wave irradiation. For example, the mounting angle of the ultrasonic sensor 24A may be variable, and the direction of ultrasonic wave irradiation by the ultrasonic sensor 24A may be scanned by a driving unit (not shown). Alternatively, the ultrasonic sensor 24A may be of a phased array type, which will be described later. In this case, the direction of ultrasonic wave irradiation by the ultrasonic sensor 24A can also be scanned. In this way, the range of ultrasonic wave irradiation can be increased, and the range of inspection for the presence or absence of abnormalities can be expanded.

[0067] The ultrasonic sensor 24B may be disposed inside the upper portion of the stay ring 7. The ultrasonic sensor 24B may be capable of emitting ultrasonic waves toward the stay vane 3 serving as the flow path structure 12. If a joint, such as a weld, exists between the stay ring 7 and the stay vane 3, cracks can be detected by comparing the measured value with that measured in an initial state when the stay vane 3 is not worn or the like. In this way, even if a crack extending in the direction of water flow (see symbol C in FIG. 4) occurs in the stay vane 3, the detection accuracy of such a crack can be improved. The ultrasonic sensor 24B may be disposed above the stay vane 3 to be irradiated. The ultrasonic sensor 24B may be capable of irradiating ultrasonic waves from inside the upper portion of the stay ring 7 toward the stay vane 3 disposed below. Alternatively, the ultrasonic sensor 24B may be disposed inside the stay vane 3 and be capable of irradiating ultrasonic waves toward the upper end or lower end of the stay vane 3. In this case, cracks can be detected without the need for the above-mentioned comparison with the measured value measured in the initial state. The ultrasonic sensor 24B may be connected to the control unit 30 via signal wiring. The ultrasonic sensors 24B may be disposed at positions where they can irradiate the corresponding stay vanes 3 with ultrasonic waves.

[0068] The ultrasonic sensor 24B may be configured to be able to scan the direction of ultrasonic wave irradiation. For example, the mounting angle of the ultrasonic sensor 24B may be variable, and the direction of ultrasonic wave irradiation by the ultrasonic sensor 24B may be scanned by a drive unit (not shown). Alternatively, the ultrasonic sensor 24B may be of a phased array type (described later), and in this case, the direction of ultrasonic wave irradiation by the ultrasonic sensor 24B can also be scanned. In this way, the range of ultrasonic wave irradiation can be increased, and the range of inspection for the presence or absence of abnormalities can be expanded.

[0069] The ultrasonic sensor 21C described above may also be configured to be able to scan the direction of ultrasonic wave irradiation. This allows for improved detection accuracy even when a crack (see symbol C in FIG. 4) extending in the direction of water flow occurs in the outlet band side portion 5f. For example, the ultrasonic sensor 21C may be of a phased array type, which will be described later. This allows for scanning of the direction of ultrasonic wave irradiation by the ultrasonic sensor 21C. This allows for an increased range of ultrasonic wave irradiation, and therefore an increased range of inspection for the presence or absence of abnormalities.

[0070] The ultrasonic sensors 24A and 24B according to the present embodiment may be configured to receive sounds of a different frequency from the frequency of the ultrasonic waves they emit. In this case, they can detect the impact that occurs when a foreign object that has entered the internal flow path 11 collides with the flow path structure 12 or the flow path defining portion 13. This makes it possible to quickly check whether or not an abnormality occurs in the flow path structure 12 after the collision by inspecting the flow path structure 12.

[0071] (Third embodiment) Next, a hydraulic machine flow path structure inspection system according to a third embodiment will be described with reference to FIG.

[0072] The third embodiment shown in Fig. 5 differs mainly in that the ultrasonic sensor is of a phased array type, and other configurations are substantially the same as those of the first embodiment shown in Fig. 1 to Fig. 3. In Fig. 5, the same parts as those of the first embodiment shown in Fig. 1 to Fig. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0073] 5, the ultrasonic sensors 21A to 21D, 22A, 22B, and 23A to 23D of the flow path structure inspection system 20 according to this embodiment may be of a phased array type. All of the ultrasonic sensors 21A to 21D, 22A, 22B, and 23A to 23D may be of a phased array type, but some of the ultrasonic sensors may not be of a phased array type.

[0074] 5 shows a schematic cross-sectional view of a phased array ultrasonic sensor. The phased array ultrasonic sensor includes a plurality of transducers 25 (elements). A control unit 30 controls the timing of pulses applied to each transducer 25, thereby enabling scanning of the direction of ultrasonic irradiation. This makes it possible to increase the ultrasonic irradiation range and therefore the inspection range for detecting abnormalities.

[0075] 5, a phased array ultrasonic sensor 21A is housed in a groove 40 formed on each of the pressure surface 5cP and the suction surface 5cN of the runner blade 5c. The ultrasonic sensor 21A is covered with a cover member 41. The surface of the cover member 41 is formed so as to be continuous with the pressure surface 5cP or the suction surface 5cN.

[0076] (Fourth embodiment) Next, a hydraulic machine flow path structure inspection system according to a fourth embodiment will be described with reference to FIGS.

[0077] In the fourth embodiment shown in Figures 6 and 7, a plurality of ultrasonic sensors are arranged at intervals around the circumferential direction of the runner in a flow path defining portion that defines the internal flow path, and based on the rotational position of the runner, ultrasonic sensors that can irradiate ultrasonic waves to the runner blades when the runner is located at that rotational position are caused to irradiate ultrasonic waves, with the other configuration being substantially the same as that of the first embodiment shown in Figures 1 to 3. Note that in Figures 6 and 7, the same parts as those in the first embodiment shown in Figures 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0078] 6 and 7, the flow path structure inspection system 20 according to this embodiment further includes a position sensor 35 and a plurality of ultrasonic sensors arranged in a flow path defining portion 13 that defines the internal flow path 11. The ultrasonic sensor according to this embodiment irradiates ultrasonic waves from outside the flow path structure 12. More specifically, the ultrasonic sensor irradiates ultrasonic waves from the flow path defining portion 13 that defines the internal flow path 11. The plurality of ultrasonic sensors includes a plurality of ultrasonic sensors 26A, a plurality of ultrasonic sensors 26B, and a plurality of ultrasonic sensors 26C.

[0079] The position sensor 35 is configured to detect the rotational position of the runner 5. The rotational position of the runner 5 detected by the position sensor 35 is transmitted to the control unit 30 as a signal.

[0080] The ultrasonic sensor 26A may be disposed on the upper cover 8. The ultrasonic sensor 26A may be configured to emit ultrasonic waves toward either the outlet crown side 5e or the central crown side 5g of the runner blade 5c. The ultrasonic sensor 26A may be configured to emit ultrasonic waves from the upper cover 8 toward the outlet crown side 5e or the central crown side 5g. The irradiation surface of the ultrasonic sensor 26A may be exposed to the internal flow path 11 from the upper cover 8. In the example shown in FIG. 6, the direction of ultrasonic waves emitted by the ultrasonic sensor 26A is inclined relative to the irradiation surface of the ultrasonic sensor 26A. However, the ultrasonic sensor 26A may be disposed so that the irradiation direction is perpendicular to the irradiation surface. This also applies to ultrasonic sensors 26B and 26C, which will be described later. The ultrasonic sensor 26A is connected to the control unit 30 via signal wiring. An example in which ultrasonic waves are emitted toward the outlet crown side 5e will be described below.

[0081] As shown in Fig. 7, multiple ultrasonic sensors 26A may be arranged at intervals in the circumferential direction of the runner 5. Fig. 7 shows an example in which multiple ultrasonic sensors 26A are arranged at equal intervals in the circumferential direction of the runner 5. When the runner 5 is positioned at a predetermined rotational position, each ultrasonic sensor 26A receives a command from the control unit 30 and irradiates ultrasonic waves toward the corresponding runner blade 5c.

[0082] Based on the rotational position of the runner 5 detected by the position sensor 35, the control unit 30 controls the ultrasonic sensors 26A capable of emitting ultrasonic waves to the runner blades 5c when the runner 5 is positioned at that rotational position. For example, when the runner 5 is positioned as shown in FIG. 7, the control unit 30 selects ultrasonic sensors 26A capable of emitting ultrasonic waves to the runner blades 5c. In this case, two ultrasonic sensors 26A are selected that are positioned so that ultrasonic waves can be directly emitted to the target runner blade 5c. The ultrasonic waves emitted from the selected two ultrasonic sensors 26A do not strike other runner blades 5c. These two ultrasonic sensors 26A emit ultrasonic waves toward the outlet crown side 5e of the target runner blade 5c. This allows the presence or absence of cavitation erosion, wear due to sediment inflow, and cracks due to stress concentration to be inspected in the target outlet crown side 5e.

[0083] The ultrasonic sensor 26B may be disposed on the lower cover 9. The ultrasonic sensor 26B may be capable of emitting ultrasonic waves toward the inlet band side portion 5d of the runner blade 5c. The ultrasonic sensor 26B may be capable of emitting ultrasonic waves from the lower cover 9 toward the inlet band side portion 5d. The emitting surface of the ultrasonic sensor 26B may be exposed from the lower cover 9 to the internal flow path 11. The ultrasonic sensor 26B is connected to the control unit 30 via a signal wiring.

[0084] As shown in Fig. 7, multiple ultrasonic sensors 26B may be arranged at intervals in the circumferential direction of the runner 5. Fig. 7 shows an example in which multiple ultrasonic sensors 26B are arranged at equal intervals in the circumferential direction of the runner 5. When the runner 5 is positioned at a predetermined rotational position, each ultrasonic sensor 26B receives a command from the control unit 30 and irradiates ultrasonic waves toward the corresponding runner blade 5c.

[0085] Based on the rotational position of the runner 5 detected by the position sensor 35, the control unit 30 controls the ultrasonic sensors 26B capable of emitting ultrasonic waves to the runner blades 5c when the runner 5 is positioned at that rotational position. For example, when the runner 5 is positioned as shown in FIG. 7, the control unit 30 selects ultrasonic sensors 26B capable of emitting ultrasonic waves to the runner blades 5c. Here, two ultrasonic sensors 26B positioned so that they can directly irradiate the target runner blade 5c are selected. The ultrasonic waves emitted from the selected two ultrasonic sensors 26B do not strike other runner blades 5c. These two ultrasonic sensors 26B irradiate ultrasonic waves toward the inlet band side 5d of the target runner blade 5c. This allows the presence or absence of cavitation erosion, wear due to sediment inflow, and cracks due to stress concentration to be inspected for inlet band side 5d.

[0086] The ultrasonic sensor 26C may be disposed in the draft tube 6 disposed downstream of the runner 5. The ultrasonic sensor 26C may be capable of emitting ultrasonic waves toward the outlet band side portion 5f of the runner blade 5c. The ultrasonic sensor 26C may be capable of emitting ultrasonic waves from the draft tube 6 toward the outlet band side portion 5f. The emitting surface of the ultrasonic sensor 26C may be exposed from the draft tube 6 to the internal flow path 11. The ultrasonic sensor 26C is connected to the control unit 30 via a signal wiring.

[0087] Although not shown, multiple ultrasonic sensors 26C may be arranged at intervals in the circumferential direction of the runner 5. When the runner 5 is positioned at a predetermined rotational position, each ultrasonic sensor 26C receives a command from the control unit 30 and irradiates ultrasonic waves toward the corresponding runner blade 5c.

[0088] The control unit 30 causes the ultrasonic sensor 26C, which is capable of emitting ultrasonic waves to the runner blades 5c when the runner 5 is located at the rotational position of the runner 5 detected by the position sensor 35, to emit ultrasonic waves. In the same manner as the ultrasonic sensors 26A and 26B, the control unit 30 may select the ultrasonic sensor 26C to emit ultrasonic waves.

[0089] In this embodiment, the ultrasonic sensors 26A to 26C are arranged in a stationary system rather than on the runner 5, so that the rotary connector 34 as shown in FIG. 2 can be eliminated.

[0090] According to each of the above-described embodiments, it is possible to easily and quickly check whether or not an abnormality has occurred in the flow path structure 12.

[0091] In the above-described embodiment, a Francis pump-turbine has been used as an example of a hydraulic machine, but the present invention is not limited to this. The hydraulic machine according to the present embodiment may be applied to hydraulic turbines other than Francis turbines. Furthermore, the hydraulic machine according to the present embodiment may be applied to hydraulic machines other than pump-turbines that do not have a pump function.

[0092] Although the present invention has been described with reference to an embodiment and several modifications thereof, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. These novel embodiments and modifications may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, it is of course possible to combine these embodiments and modifications in part as appropriate within the spirit of the invention. [Explanation of symbols]

[0093] 1: Francis pump-turbine, 3: stay vane, 4: guide vane, 5: runner, 5a: crown, 5b: band, 5c: runner blade, 6: draft tube, 11: internal flow path, 12: flow path structure, 13: flow path defining portion, 20: flow path structure inspection system, 21A to 21D: ultrasonic sensors, 22A, 22B: ultrasonic sensors, 23A to 23D: ultrasonic sensors, 24A, 24B: ultrasonic sensors, 26A to 26C: ultrasonic sensors, 30: control unit, 33: display unit, 35: position sensor

Claims

1. A hydraulic machine flow path structure inspection system for inspecting a flow path structure disposed in an internal flow path through which water flows passing through a runner of the hydraulic machine, comprising: at least one ultrasonic sensor that irradiates the flow path structure with ultrasonic waves and detects reflected waves of the ultrasonic waves; a control unit that controls the emission of ultrasonic waves by the ultrasonic sensor and receives an output signal from the ultrasonic sensor; a display unit that displays an inspection result based on the output signal; A hydraulic machine flow path structure inspection system comprising:

2. the flow path structure includes a runner blade of the runner, the at least one ultrasonic sensor is disposed inside a runner blade of the runner and includes an ultrasonic sensor capable of emitting ultrasonic waves toward a band-side end of an upstream edge portion of the runner blade. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

3. the flow path structure includes a runner blade of the runner, the at least one ultrasonic sensor is disposed inside a runner blade of the runner and includes an ultrasonic sensor capable of emitting ultrasonic waves toward a crown side end of a downstream edge portion of the runner blade. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

4. the flow path structure includes a runner blade of the runner, the at least one ultrasonic sensor is disposed inside a runner blade of the runner and includes an ultrasonic sensor capable of emitting ultrasonic waves toward a band-side end of a downstream edge portion of the runner blade. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

5. the flow path structure includes a runner blade of the runner, the at least one ultrasonic sensor is disposed on a crown of the runner and includes an ultrasonic sensor capable of emitting ultrasonic waves toward an end portion of a runner blade of the runner on the crown side between an upstream edge portion and a downstream edge portion. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

6. the flow path structure includes a guide vane disposed upstream of the runner, the at least one ultrasonic sensor is disposed inside the guide vane and includes an ultrasonic sensor capable of emitting ultrasonic waves toward at least one of an upper end and a lower end of the guide vane; The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

7. the flow path structure includes a stay vane arranged upstream of the runner, The at least one ultrasonic sensor is disposed inside the stay vane and includes an ultrasonic sensor capable of emitting ultrasonic waves toward either an upper end or a lower end of an upstream edge portion of the stay vane. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

8. the flow path structure includes a stay vane arranged upstream of the runner, The at least one ultrasonic sensor is arranged inside the stay vane and includes an ultrasonic sensor capable of emitting ultrasonic waves toward either an upper end or a lower end of a downstream edge portion of the stay vane. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

9. the flow path structure includes a guide vane and a stay vane arranged upstream of the runner, The at least one ultrasonic sensor is arranged in a flow path defining portion that defines the internal flow path, and includes an ultrasonic sensor that can irradiate ultrasonic waves toward either the guide vane or the stay vane. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

10. The ultrasonic sensor is a phased array type. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

11. a position sensor for detecting a rotational position of the runner; a plurality of the ultrasonic sensors are disposed in a flow path defining portion that defines the internal flow path; The ultrasonic sensors are arranged at intervals in the circumferential direction of the runner, the flow path structure includes a runner blade of the runner, Each of the ultrasonic sensors is capable of emitting ultrasonic waves toward the runner blade located at a corresponding rotational position; the control unit controls the ultrasonic sensor, which is capable of irradiating ultrasonic waves to the runner blades, to irradiate ultrasonic waves when the runner is located at the rotational position of the runner detected by the position sensor. The system for inspecting a flow path structure of a hydraulic machine according to claim 1.

12. the plurality of ultrasonic sensors are arranged on an upper cover that defines the internal flow path, and include ultrasonic sensors that can irradiate ultrasonic waves toward either a crown-side end of a downstream edge of the runner vane or a crown-side end of the runner vane between an upstream edge and a downstream edge. The system for inspecting a flow path structure of a hydraulic machine according to claim 11.

13. the plurality of ultrasonic sensors are arranged on a lower cover that defines the internal flow path, and include an ultrasonic sensor that is capable of irradiating an end portion of an upstream edge portion of the runner blade on a band side with ultrasonic waves; The system for inspecting a flow path structure of a hydraulic machine according to claim 11.

14. the plurality of ultrasonic sensors include an ultrasonic sensor that is disposed in a draft pipe disposed downstream of the runner and that is capable of irradiating an end portion of a downstream edge portion of the runner vane on a band side with ultrasonic waves; The system for inspecting a flow path structure of a hydraulic machine according to claim 11.

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