AE sensor mount structure, AE sensor mount support device, and AE sensor mounting method

Abstract

To provide an AE sensor mount structure, an AE sensor mount support device, and an AE sensor mounting method capable of mounting an AE sensor to a predetermined mount position constantly stably even if the AE sensor is re-mounted.SOLUTION: AE sensor mount structure includes a waveguide bar that is installed so as to project from the surface of a double screw extrusion molding machine (specimen) and transmits an AE signal generated by the double screw extrusion molding machine, a plate that is mounted to the tip end of the waveguide rod and transmits an AE signal, a mounting tool (mount member) that is screwed to a predetermined position of the plate, where an AE sensor for detecting the AE signal is inserted so as to prevent movement of an abutting position to the plate on a sensor surface inside, and a screw that is inserted toward a surface in the side opposite to the sensor surface of the AE sensor relative to the mounting tool and adjusts pressing force to the plate on the sensor surface, and mounts the AE sensor to the plate by clamping a screw with preset clamping force.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an AE sensor mounting structure, an AE sensor mounting support device, and an AE sensor mounting method. [Background technology]

[0002] Conventionally, in order to monitor the state of a workpiece undergoing heat treatment, for example, a method has been used in which an AE sensor detects elastic waves (AE signals) generated inside the specimen. When performing such evaluation, the AE sensor is fixed by pressing it against the surface of a treatment vessel containing the workpiece with spring pressure (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-009513 A Summary of the Invention [Problem to be solved by the invention]

[0004] The AE sensor is generally attached to the surface of the processing vessel by a magnet via a mounting jig. The mounting jig presses the sensor surface of the AE sensor against the specimen by rubber, Teflon (registered trademark), springs, etc. In this mounting method, since the sensor is attached using a magnet, it is not possible to keep the mounting position constant when the AE sensor is removed for each measurement. In addition, since the sensor surface of the AE sensor cannot always be pressed against the specimen with a constant pressing force, there is a problem that when the AE sensor needs to be reattached for each measurement, the measurement results obtained vary each time the AE sensor is reattached.

[0005] The present invention has been made in consideration of the above, and has an object to provide an AE sensor mounting structure, an AE sensor mounting assistance device, and an AE sensor mounting method that enable the AE sensor to always be stably mounted in a specified mounting position even if the AE sensor is reattached. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the AE sensor mounting structure of the present invention comprises a waveguide rod installed so as to protrude from a surface of a test object and transmitting an AE signal generated in the test object, a plate attached to the tip of the waveguide rod and transmitting the AE signal, a mounting member screwed to a predetermined position of the plate and having an AE sensor therein for detecting the AE signal, inserted so as to prevent movement of the contact position of the sensor face of the AE sensor with the plate, and a screw inserted into the mounting member toward the side opposite to the sensor face of the AE sensor and tightening or loosening to adjust the pressing force of the sensor face against the plate, and the AE sensor is mounted to the plate by tightening the screw with a preset tightening force.

[0007] The AE sensor attachment assisting device according to the present invention includes: a waveguide rod that is installed so as to protrude from a surface of an object to be inspected and transmits an AE signal generated in the object to be inspected; a plate that is attached to the tip of the waveguide rod and transmits the AE signal; an attachment member that is screwed to a predetermined position of the plate and has an AE sensor therein that detects the AE signal, the attachment member being inserted so as to prevent movement of a contact position of a sensor surface of the AE sensor against the plate; a screw that is inserted into the attachment member toward a surface opposite to the sensor surface of the AE sensor and that adjusts a pressing force of the sensor surface against the plate by tightening or loosening; a signal analysis unit that detects an AE signal generated when an ultrasonic wave generated by a reference signal generator that generates ultrasonic waves of a predetermined frequency is applied to the object to be inspected, the signal analysis unit detects with the AE sensor an AE signal generated when the ultrasonic wave is generated by a reference signal generator that generates ultrasonic waves of a predetermined frequency, and calculates a magnitude of a predetermined frequency component of the AE signal; and an alarm unit that issues an alarm when the magnitude of the predetermined frequency component calculated by the signal analysis unit reaches a predetermined value each time the fastening force of the screw is changed. It is characterized by:

[0008] In addition, the AE sensor mounting method of the present invention is characterized in that an AE signal of a predetermined frequency is generated in an object to be inspected, the AE signal is transmitted to a waveguide rod installed so as to protrude from a surface of the object to be inspected and to a plate attached to the tip of the waveguide rod, and an AE sensor that is screwed to a predetermined position of the plate and detects the AE signal therein is attached to the plate by adjusting the fastening force of a screw inserted toward a surface opposite to the sensor surface of the AE sensor of a mounting member inserted so as to prevent movement of the contact position of the sensor surface of the AE sensor against the plate, thereby adjusting the pressing force of the sensor surface against the plate so that the magnitude of a predetermined frequency component of the AE signal detected by the AE sensor becomes a predetermined value. Effect of the Invention

[0009] According to the AE sensor mounting structure, AE sensor mounting assistance device, and AE sensor mounting method of the present invention, the AE sensor can always be stably mounted in a specified mounting position, and the stability of the detected AE signal can be maintained even if the AE sensor is remounted. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of acoustic emission. [Diagram 2] FIG. 2 is a schematic structural diagram showing an example of a twin-screw extruder. [Diagram 3] FIG. 3 is a mounting structure diagram showing an example of a mounting structure for an AE sensor. [Figure 4] FIG. 4 is an exploded perspective view showing an example of an AE sensor mounting structure. [Diagram 5] FIG. 5 is a diagram showing an example of a change in a signal waveform according to a pressing force of the AE sensor. [Figure 6] FIG. 6 is a hardware block diagram showing an example of a hardware configuration of the AE wave analysis device. [Figure 7] FIG. 7 is a functional block diagram showing an example of a functional configuration of the AE wave analysis device. [Figure 8] FIG. 8 is a flowchart showing an example of the flow of processing performed by the AE wave analysis device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Explanation of Acoustic Emission (AE)] Before describing the embodiment, acoustic emission (hereinafter, referred to as AE) used to evaluate the operating state of an extruder during operation will be described. AE is a phenomenon in which, for example, when a resin raw material (pellets) is kneaded in an extruder, when pellets, which are solid materials, are crushed, or when a reinforcing material, such as glass fiber, carbon fiber, or cellulose fiber, mixed in to reinforce the resin raw material, breaks, the accumulated strain energy is released as sound waves (elastic waves, AE waves). By detecting and analyzing the AE waves generated by the crushing of pellets or the breakage of reinforcing materials, it is possible to predict the kneading state of the resin material put into the extruder and the kneading state of the reinforcing material. The frequency band of the AE waves is said to be about several tens of kHz to several MHz, and has a frequency band that cannot be detected by general vibration sensors or acceleration sensors. Therefore, a dedicated AE sensor is used to detect the AE waves. The AE sensor will be described in detail later.

[0012] Fig. 1 is an explanatory diagram of acoustic emission. As shown in Fig. 1, when pellets are crushed or a reinforcing material is broken at a point P inside a twin-screw extruder 30, an AE wave W is generated. The AE wave W spreads radially from the point P and penetrates into the inside of the housing of the twin-screw extruder 30. The AE wave W that penetrates into the inside of the housing propagates inside the housing of the twin-screw extruder 30. The twin-screw extruder 30 is an example of a subject in the present disclosure.

[0013] The AE wave W propagated inside the housing of the twin-screw extruder 30 is detected by the AE sensor 20 installed on the surface of the housing of the twin-screw extruder 30. The AE sensor 20 outputs a detection signal D. The detection signal D is an AC signal having positive and negative values ​​as shown in FIG. 1, since it is a signal representing vibration. Since it is difficult to handle the detection signal D (AE wave W) as it is when performing various calculations, the detection signal D is generally treated as a rectified waveform in which the negative part of the detection signal D is half-wave rectified. Furthermore, when analyzing the AE wave W, it is generally treated as a value obtained by averaging the squared value of the rectified waveform over a predetermined time and taking the square root, that is, an effective value (Root Mean Square (RMS) value).

[0014] The propagation speed of the AE waves W differs between longitudinal waves and shear waves (longitudinal waves are faster than shear waves), but when the size (propagation distance) of the solid material Q is taken into consideration, this difference can be ignored. Therefore, in this embodiment, the AE waves W detected within a specified time are analyzed as measurement signals, regardless of whether they are longitudinal waves or shear waves.

[0015] [Outline of twin-screw extruder structure] The AE sensor 20 of this embodiment is installed in, for example, a twin-screw extruder 30 to monitor the operating state of the twin-screw extruder 30. The twin-screw extruder 30 is an example of a subject in the present disclosure. Hereinafter, a schematic structure of the twin-screw extruder 30 will be described with reference to Fig. 2. Fig. 2 is a schematic structural diagram showing an example of a twin-screw extruder.

[0016] The twin-screw extruder 30 is driven according to the output of a gear box 40. The gear box 40 reduces the rotational drive force of the motor 31, and drives two output shafts 42 of the twin-screw extruder 30 to rotate in the same direction. A screw 44 and a kneading disk 46, which will be described later, are provided on the outer periphery of the output shaft 42, and as the output shaft 42 rotates, the resin raw material (pellets) fed into the twin-screw extruder 30 is plasticized and melted, kneaded, and molded, and a reinforcing material mixed into the molten resin raw material is kneaded to improve the strength of the resin raw material.

[0017] The two output shafts 42 are arranged parallel to each other along the Y axis, separated by a certain inter-axial distance C in the X axis direction, inside a cylindrical housing (barrel) 32 of the twin-screw extruder 30. A heater 39 is attached to the outer circumferential surface of the housing 32 for heating the housing 32 to melt the pellets fed into the twin-screw extruder 30.

[0018] The housing 32 is provided with insertion holes 34 into which the output shafts 42 are inserted. The insertion holes 34 are holes provided along the longitudinal direction of the housing 32 and have a shape of partially overlapping cylinders. This allows the screw 44 and the kneading disk 46 to be inserted into the insertion holes 34 in a state of meshing with each other.

[0019] The output shaft 42 rotates the screw 44 inside the insertion hole 34. The output shaft 42 also rotates the kneading disc 46 inside the insertion hole 34.

[0020] The screw 44 rotates at a speed of, for example, 300 revolutions per minute, thereby transporting the molten resin raw material and the glass fibers mixed in the resin raw material, which are input into the twin-screw extruder 30, to the downstream side of the twin-screw extruder 30. The screws 44 of each output shaft 42 mesh with each other to transport the molten resin raw material downstream. The glass fibers mixed in the resin raw material are subjected to a large shearing force when passing through the meshing portion of the kneading discs 46 of each output shaft 42, and are broken and kneaded into the resin raw material.

[0021] The kneading disc 46 has a structure in which multiple elliptical discs are arranged in a direction perpendicular to the output shaft 42, and the orientation of adjacent discs is shifted along the output shaft 42. By arranging adjacent discs in a shifted manner, the flow of the resin raw material is divided between the discs, thereby promoting kneading of the transported resin raw material and the glass fibers mixed in the resin raw material. That is, the kneading disc 46 is heated by the heater 39, and imparts shear energy to the resin raw material transported by the screw 44, thereby completely melting the resin raw material.

[0022] A supply port 36a is provided at one end side in the longitudinal direction of the housing 32 (negative side in the Y-axis direction) for feeding pellet-shaped resin raw material and powder-shaped filler material to be mixed into the insertion hole 34. A reinforcing material such as glass fiber is fed from a supply port 36b provided in a side feeder 37 downstream of the supply port 36a. The supply direction of the raw materials through the supply ports 36a and 36b is not limited to the example shown in FIG.

[0023] At the other end side in the longitudinal direction of the housing 32 (the positive side in the Y-axis direction), a discharge port 38 is provided for discharging the material kneaded while passing through the insertion hole 34.

[0024] Since a heater 39 that reaches a high temperature of about 200° C. is attached to the surface of the housing 32 of the twin-screw extruder 30, the AE sensor 20, which has a heat resistance temperature of about 80° C., cannot be directly installed on the housing 32. For this reason, the AE sensor 20 is installed via a waveguide rod 21 (waveguide) installed on the surface of the housing (barrel) 32 of the twin-screw extruder 30, which is the test subject. The waveguide rod 21 is made of, for example, ceramic or stainless steel, and transmits the AE wave W that has propagated inside the housing 32 to the AE sensor 20.

[0025] A male screw is formed at the tip of the waveguide rod 21 on the twin-screw extruder 30 side. The waveguide rod 21 is attached to the housing 32 of the twin-screw extruder 30 by fastening this male screw to a female screw formed in the housing 32 of the twin-screw extruder 30.

[0026] A plate 22 is fastened to the other end of the waveguide rod 21. The plate 22 has a rectangular parallelepiped shape, and the AE sensor 20 is fixed to a side surface of the plate 22. The details of the mounting structure of the AE sensor 20 will be described later (see FIG. 3).

[0027] The AE sensor 20 detects the magnitude of the AE waves W generated in the twin-screw extruder 30. The detected AE waves W are subjected to frequency analysis by the AE wave analyzer 10. The AE wave analyzer 10 monitors the kneading state of the resin material and the kneading state of the reinforcing material in the twin-screw extruder 30 based on the amplitude of the frequency components in a specific frequency range, etc.

[0028] In the example of Fig. 2, the output shaft 42 of the twin-screw extruder 30 is provided with two screws 44 and one kneading disc 46, but the numbers of the screws 44 and kneading discs 46 are not limited to those shown in the example of Fig. 2. For example, the kneading discs 46 may be provided in multiple locations to knead the resin raw material and break the glass fibers at multiple locations.

[0029] Furthermore, the twin-screw extruder 30 is just an example, and the AE sensor 20 of this embodiment is applicable to all extruders, such as single-screw extruders and multi-screw extruders.

[0030] [AE sensor mounting structure] The mounting structure of the AE sensor 20 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a mounting structure diagram showing an example of the mounting structure of the AE sensor. Fig. 4 is an exploded perspective view showing an example of the mounting structure of the AE sensor.

[0031] A male screw is formed at one end 21a of the waveguide rod 21, and is fastened to a female screw formed on the surface of a housing 32 of the twin-screw extruder 30, which is the test object. The waveguide rod 21 may be further fastened in a state of being fitted into the housing 32.

[0032] The other end 21 b of the waveguide rod 21 is formed with a male thread, which is fastened to a female thread formed in the plate 22 .

[0033] The AE sensor 20 is installed via a mounting jig 23 so that the sensor surface that detects AE waves abuts on a predetermined position on the side of the plate 22. The mounting jig 23 is fixed to the plate 22 by screws 24a and 24b with the AE sensor 20 embraced within the mounting jig 23. In addition, the top of the AE sensor 20 opposite the sensor surface is pressed against the plate 22 by tightening a screw 25a that passes through the mounting jig 23. This causes the sensor surface to be pressed against the plate 22. A method for fixing the AE sensor 20 will be described in detail later (see FIG. 4). The mounting jig 23 is an example of a mounting member in this disclosure.

[0034] A part of the side surface of the mounting jig 23 is cut out, and an output terminal 26 that outputs an AE signal detected by the AE sensor 20 is exposed in the cutout portion.

[0035] In addition, since the AE waves detected by the AE sensor 20 are weak, in order to suppress the effects of noise contamination, a preamplifier (not shown) may be installed inside the AE sensor 20 to amplify the detection signal in advance before outputting it.

[0036] Next, the mounting structure of the AE sensor 20 will be described in more detail with reference to Fig. 4. Fig. 4 is an exploded perspective view of parts involved in mounting the AE sensor 20.

[0037] The inside of the mounting jig 23 is hollowed out so that the cylindrical AE sensor 20 can be inserted therein. In addition, a notch is provided in the side surface of the mounting jig 23 on the positive side of the Z axis, through which the output terminal 26 passes.

[0038] The mounting jig 23, with the AE sensor 20 held inside, is fixed to a predetermined position on the plate 22 by screws 24a and 24b.

[0039] The screw 24a has a male thread and is fastened through a drilled hole 23a formed in the mounting jig 23 to a female-threaded screw hole 22a formed in the plate 22. The screw 24b has a male thread and is fastened through a drilled hole 23b formed in the mounting jig 23 to a female-threaded screw hole 22b formed in the plate 22.

[0040] A screw hole 23d having a female thread is formed in the side surface on the negative side of the Z axis of the mounting jig 23. A screw 25b having a male thread is screwed into the screw hole 23d. The screw 25b penetrates the mounting jig 23 and abuts against the side surface of the AE sensor 20, preventing the AE sensor 20 from rotating around the Y axis inside the mounting jig 23.

[0041] A screw hole 23c having a female thread is formed in the top of the mounting jig 23. A screw 25a having a male thread is screwed into the screw hole 23c. The screw 25a penetrates the mounting jig 23 and abuts against the top of the AE sensor 20, causing the sensor surface 20a of the AE sensor 20 to be pressed against the plate 22.

[0042] Although not shown in Fig. 4, an AE wave analyzer 10 (see Fig. 6) that performs frequency analysis of the AE signal and calculates the intensity of a predetermined frequency component is connected to the output terminal 26 that outputs the AE signal. An operator who installs the AE sensor 20 on the plate 22 monitors the intensity of the predetermined frequency component calculated by the AE wave analyzer 10 on the display device 15 and adjusts the tightening force of the screw 25a so that the intensity becomes a predetermined value or a value within a predetermined range. The display device 15 is an example of a monitor unit in the present disclosure.

[0043] [Changes in signal waveform due to pressure applied to the sensor surface of the AE sensor] The phenomenon in which the signal waveform changes depending on the pressing force of the AE sensor 20 will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the change in the signal waveform according to the pressing force of the AE sensor.

[0044] The inventors of the present disclosure have found through experiments that when the pressing force with which the AE sensor 20 is pressed against the plate 22 is changed, the frequency and amplitude of the detected AE wave W change.

[0045] An example of the experimental data is shown in Fig. 5. The horizontal axis of Fig. 5 represents frequency, and the vertical axis represents intensity (amplitude) for each frequency obtained by frequency analysis of the AE wave W detected by the AE sensor 20.

[0046] Fig. 5 shows four graphs, 50a, 50b, 50c, and 50d, each of which has a different tightening force of the screw 25a described in Fig. 4. That is, the tightening force of the screw 25a increases in the order of graph 50a, graph 50b, graph 50c, and graph 50d.

[0047] A crush signal 51a shown in graph 50a is a signal indicating that crushing of pellets has occurred inside the twin-screw extruder 30 in which the AE sensor 20 is installed. Similarly, a crush signal 51b shown in graph 50b, a crush signal 51c shown in graph 50c, and a crush signal 51d shown in graph 50d are also signals indicating that crushing of pellets has occurred in the twin-screw extruder 30 in which the AE sensor 20 is installed. The crush signals 51a, 51b, 51c, and 51d indicate the results of detecting the same crush signal generated in the twin-screw extruder 30.

[0048] 5, it can be seen that the frequency band of the AE wave W indicating the occurrence of crushing of the pellets shifts to a higher frequency band as the fastening force of the screw 25a increases, i.e., the stronger the pressure of the sensor surface 20a of the AE sensor 20 is pressed against the plate 22. This is presumably because, unless a certain level of contact pressure is secured between the sensor surface 20a and the plate 22, the frequency component of the AE wave W indicating the occurrence of crushing cannot be detected normally due to the influence of device vibration.

[0049] It is also found that the signal strength of the AE wave W indicating the occurrence of crushing increases as the tightening force of the screw 25a increases, i.e., the stronger the sensor surface 20a of the AE sensor 20 is pressed against the plate 22. This is presumably because the sensor surface 20a of the AE sensor 20 and the surface of the twin-screw extruder 30 are pressed together more strongly, which reduces the attenuation of the AE wave W at the sensor surface 20a.

[0050] From the experimental results shown in Fig. 5, it can be seen that if it is necessary to remove the AE sensor 20 each time the operating state of the twin-screw extruder 30 is monitored, it is necessary to adjust the tightening force of the screws 25a so that it is equal when attaching the AE sensor 20 to the plate 22. If this adjustment is not performed, as shown in Fig. 5, when the same AE wave W is emitted from the twin-screw extruder 30, the AE sensor 20 will detect signals of different frequencies and different magnitudes, and it will not be possible to correctly monitor the operating state of the twin-screw extruder 30.

[0051] When attaching the AE sensor 20 to the plate 22, the AE wave analysis device 10 of this embodiment applies a reference signal of a predetermined frequency generated by, for example, an ultrasonic generator 18 to the test object, and detects an AE wave corresponding to the reference signal. The AE wave analysis device 10 calculates the magnitude of the predetermined frequency component of the detected AE signal. The worker installing the AE sensor 20 monitors the calculated magnitude of the predetermined frequency component on the display device 15, and installs the AE sensor 20 by adjusting the tightening force of the screw 25a so that the signal magnitude becomes a predetermined value or a value within a predetermined range.

[0052] Also, instead of monitoring the magnitude of the predetermined frequency component calculated by the AE wave analyzer 10 on the display device 15, the tightening force of the screw 25a may be monitored, for example, by a torque wrench. In this case, the target tightening force of the screw 25a is determined in advance, for example, from the results of the graphs 50a, 50b, 50c, and 50d in FIG. 5 and the tightening force of the screw 25a at that time. Then, when attaching the AE sensor 20, the screw 25a is tightened, for example, by using a torque wrench, so that the tightening force of the screw 25a becomes the predetermined tightening force, so that the AE sensor 20 can be attached with a constant pressing force at all times. At this time, instead of using a signal indicating that the pellets have been crushed as shown in FIG. 5, a reference signal generated by, for example, the ultrasonic generator 18 may be given to the twin-screw extruder 30, which is the subject of the test.

[0053] [Hardware configuration of AE wave analyzer] The hardware configuration of the AE wave analysis device 10 of this embodiment will be described with reference to Fig. 6. Fig. 6 is a hardware block diagram showing an example of the hardware configuration of the AE wave analysis device.

[0054] The AE wave analysis device 10 of this embodiment monitors the operating state of a test object such as a twin-screw extruder 30. The AE wave analysis device 10 also assists in the appropriate installation of an AE sensor 20 that observes AE waves generated in a test object such as a twin-screw extruder 30. The AE wave analysis device 10 is an example of an AE sensor installation assistance device in the present disclosure.

[0055] The AE wave analyzer 10 is used in connection with a twin-screw extruder 30 , and includes a control unit 11 , a storage unit 12 , and a peripheral device controller 13 .

[0056] The control unit 11 includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, and a RAM (Random Access Memory) 113. The CPU 111 is connected to the ROM 112 and the RAM 113 via an internal bus. The CPU 111 reads out a control program 121 stored in the storage unit 12 and various data stored in the ROM 112, and loads them in the RAM 113. The CPU 111 operates according to the control program 121 loaded in the RAM 113, thereby controlling the operation of the control unit 11. That is, the control unit 11 has the configuration of a general computer that operates based on the control program 121.

[0057] The storage unit 12 is a non-volatile memory such as a flash memory that retains stored information even when the power is turned off, or an HDD (Hard Disk Drive), etc. The storage unit 12 stores programs including a control program 121. The control program 121 is a program for implementing functions of the control unit 11. The control program 121 may be provided by being incorporated in the ROM 112 in advance.

[0058] The peripheral device controller 13 is connected to an ultrasonic generator driver 14, a display device 15, and an A / D converter 16. Based on instructions from the control unit 11, the peripheral device controller 13 controls the operation of each device connected thereto.

[0059] The ultrasonic generator driver 14 instructs the ultrasonic generator 18 to generate and stop ultrasonic waves.

[0060] The ultrasonic generator 18 generates ultrasonic waves of a predetermined frequency and intensity in response to an instruction from the ultrasonic generator driver 14. The ultrasonic generator 18 is an example of a reference signal generator in the present disclosure.

[0061] The display device 15 notifies the user that, when the AE sensor 20 is attached to the plate 22 and the screw 25a is tightened, the intensity (amplitude) of the frequency component corresponding to the signal of the ultrasonic generator 18 detected by the AE sensor 20 has reached a predetermined value or a value within a predetermined range. The display device 15 is, for example, a liquid crystal display. The display device 15 may also display various information related to the operating state of the twin-screw extruder 30.

[0062] The A / D converter 16 converts the AE wave W detected by the AE sensor 20 from the twin-screw extruder 30 into a digital signal and outputs it to the control unit 11. Although not shown in Fig. 6, the AE wave W output by the AE sensor 20 is amplified by an amplifier and then input to the A / D converter 16.

[0063] [Functional configuration of AE wave analyzer] The functional configuration of the AE wave analysis device 10 of this embodiment will be described with reference to Fig. 7. Fig. 7 is a functional block diagram showing an example of the functional configuration of the AE wave analysis device.

[0064] The control unit 11 of the AE wave analysis device 10 deploys the control program 121 in the RAM 113 and operates it to realize, as functional units, a reference signal output unit 61, an AE signal acquisition unit 62, an AE signal analysis unit 63, and an alarm unit 64 shown in FIG. 7.

[0065] The reference signal output unit 61 generates ultrasonic waves of a predetermined frequency and intensity for the ultrasonic generator 18 attached to the twin-screw extruder 30, which is the test subject.

[0066] The AE signal acquisition unit 62 acquires the AE wave W generated in the twin-screw extruder 30 that is the subject of the test.

[0067] The AE signal analysis unit 63 calculates the magnitude (e.g., amplitude) of a predetermined frequency component by performing frequency analysis of the AE wave W acquired by the AE signal acquisition unit 62. Note that any method of frequency analysis may be used, and for example, FFT or the like may be used.

[0068] The notification unit 64 determines that the AE sensor 20 is properly attached and issues a notification when the magnitude of the predetermined frequency component calculated by the AE signal analysis unit 63 becomes a predetermined value or a value within a predetermined range. The notification unit 64 issues the notification by, for example, displaying information indicating that the AE sensor 20 is properly attached on the display device 15. The notification unit 64 may also issue a notification indicating that the AE sensor 20 is properly attached by outputting sound or voice from a speaker not shown in FIG.

[0069] [Processing flow of the AE wave analyzer] The flow of processing performed by the AE wave analysis device 10 will be described with reference to Fig. 8. Fig. 8 is a flow chart showing an example of the flow of processing performed by the AE wave analysis device.

[0070] The process in FIG. 8 starts from a state in which the AE sensor 20 is mounted on the plate 22 by the mounting jig 23 and the screw 25a is fastened with a temporary tightening force.

[0071] The reference signal output unit 61 causes the ultrasonic generator 18 installed at an arbitrary position in the housing 32 of the twin-screw extruder 30 to generate ultrasonic waves of a predetermined frequency and a predetermined intensity (step S11). The ultrasonic waves generated by the ultrasonic generator 18 at this time are signals that mimic actual AE waves.

[0072] The AE signal acquisition unit 62 acquires an AE signal due to the ultrasonic waves generated by the ultrasonic generator 18 by the AE sensor 20 (step S12).

[0073] The AE signal analysis unit 63 performs frequency analysis on the AE signal acquired by the AE signal acquisition unit 62 to calculate the amplitude of a signal of a predetermined frequency (step S13).

[0074] The notification unit 64 determines whether the magnitude (e.g., amplitude) of the predetermined frequency component calculated by the AE signal analysis unit 63 is within a predetermined range (step S14). If it is determined that the amplitude of the predetermined frequency component is within the predetermined range (step S14: Yes), the process proceeds to step S15. On the other hand, if it is not determined that the amplitude of the predetermined frequency component is within the predetermined range (step S14: No), the process returns to step S12. At this time, the operator changes the tightening force of the screw 25a. The notification unit 64 may determine whether the amplitude of the predetermined frequency component calculated by the AE signal analysis unit 63 is a predetermined value.

[0075] If it is determined in step S14 that the amplitude of the predetermined frequency component is within the predetermined range, the notification unit 64 displays on the display device 15 a notification that the attachment of the AE sensor 20 has been completed (step S15).

[0076] The reference signal output unit 61 stops the output of ultrasonic waves from the ultrasonic generator 18 (step S16). After that, the AE wave analyzer 10 ends the process of FIG.

[0077] Thereafter, the ultrasonic generator 18 is removed from the twin-screw extruder 30. Then, the twin-screw extruder 30 is operated, and monitoring of the AE signal by the AE sensor 20 begins.

[0078] [Modification of the embodiment] In the above description, a case has been described in which one AE sensor 20 is installed in the twin-screw extruder 30. However, a plurality of AE sensors 20 may be installed in the twin-screw extruder 30, and the AE signal acquired by each AE sensor 20 may be analyzed by the AE wave analyzer 10 to monitor the operating state of the twin-screw extruder 30.

[0079] For example, a plurality of AE sensors 20 are installed in the twin-screw extruder 30, and an AE signal is acquired by each AE sensor 20. In this case, if the strengths and frequencies of the AE signals detected by the respective AE sensors 20 are similar, it can be estimated that the AE signals are generated at the same location in the twin-screw extruder 30. Then, based on the difference in the times at which the AE signals are acquired by the respective AE sensors 20, the location in the twin-screw extruder 30 where the abnormality has occurred can be identified.

[0080] 8, all of the AE sensors 20 are properly attached, making it possible to more accurately obtain the frequency and intensity of the AE signal detected by each AE sensor 20. Therefore, the location of the abnormality in the twin-screw extruder 30, which is calculated based on the output of each AE sensor 20, can be more accurately identified.

[0081] (Effects of the embodiment) As described above, the AE sensor mounting structure of the embodiment comprises: the waveguide rod 21 that is installed so as to protrude from the surface of the twin-screw extruder 30 (subject) and transmits the AE signal generated by the twin-screw extruder 30; the plate 22 that is attached to the tip of the waveguide rod 21 and transmits the AE signal; the mounting jig 23 (mounting member) that is screwed to a predetermined position of the plate 22 and has the AE sensor 20 therein that detects the AE signal, the mounting jig 23 being inserted so as to prevent movement of the contact position of the sensor surface 20a of the AE sensor 20 with the plate 22; and the screw 25a that is inserted into the mounting jig 23 toward the surface opposite the sensor surface 20a of the AE sensor 20 and that adjusts the pressing force of the sensor surface 20a against the plate 22 by tightening or loosening. The AE sensor 20 is mounted to the plate 22 by tightening the screw 25a with a predetermined tightening force. Therefore, the AE sensor 20 can always be stably attached to a predetermined position of the twin-screw extruder 30, and the stability of the detected AE signal can be maintained even if the AE sensor 20 is reattached.

[0082] The AE wave analysis device 10 (AE sensor mounting support device) of the embodiment includes a waveguide rod 21 that is installed so as to protrude from the surface of a twin-screw extruder 30 (subject) and transmits an AE signal generated by the twin-screw extruder 30, a plate 22 that is attached to the tip of the waveguide rod 21 and transmits the AE signal, a mounting jig 23 (mounting member) that is screwed to a predetermined position of the plate 22 and has an AE sensor 20 therein that detects the AE signal, the mounting jig 23 (mounting member) inserted so as to prevent movement of the contact position of the sensor surface 20a of the AE sensor 20 against the plate 22, and a mounting jig 23 (mounting member) that is screwed to the predetermined position of the plate 22 and has an AE sensor 20 that detects the AE signal therein. the screw 25a is inserted toward the surface opposite to the surface of the plate 22 and is tightened or loosened to adjust the pressing force of the sensor surface 20a against the plate 22, an AE signal analysis unit 63 (signal analysis unit) that detects an AE signal generated when an ultrasonic wave generated by an ultrasonic generator 18 (reference signal generator) that generates ultrasonic waves of a predetermined frequency is applied to the twin-screw extruder 30 by the AE sensor 20 and calculates the magnitude of a predetermined frequency component of the AE signal, and an alarm unit 64 that issues an alarm when the magnitude of the predetermined frequency component calculated by the AE signal analysis unit 63 reaches a predetermined value each time the tightening force of the screw 25a is changed. Therefore, the AE sensor 20 can always be stably attached at a predetermined position of the twin-screw extruder 30, and the stability of the detected AE signal can be maintained even if the AE sensor 20 is reattached.

[0083] In addition, the AE sensor mounting method of the embodiment generates an AE signal of a predetermined frequency in the twin-screw extruder 30 (subject), transmits the AE signal to the waveguide rod 21 installed so as to protrude from the surface of the twin-screw extruder 30 and the plate 22 attached to the tip of the waveguide rod 21, and mounts the AE sensor 20 on the plate 22 by adjusting the fastening force of the screw 25a inserted toward the surface opposite to the sensor surface 20a of the mounting jig 23 (mounting member) inserted so as to prevent the movement of the contact position of the sensor surface 20a against the plate 22. Therefore, the AE sensor 20 can be mounted on the plate 22 in a stable manner at all times. Therefore, even if the AE sensor 20 is remounted, the stability of the detected AE signal can be maintained.

[0084] Although the embodiments of the present invention have been described above, these embodiments are merely examples and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0085] 10...AE wave analysis device (AE sensor mounting support device), 15...display device (monitor section), 18...ultrasonic generator (reference signal generator), 20...AE sensor, 20a...sensor surface, 21...waveguide rod, 22...plate, 22a, 22b...screw hole, 23...mounting jig (mounting member), 23a, 23b...drilled hole, 23c, 23d...screw hole, 24a, 24b, 25a, 25b...screw, 26...output terminal, 30...twin-screw extruder (subject), 31...motor , 32... housing (barrel), 34... insertion hole, 36a, 36b... supply port, 37... side feeder, 38... discharge port, 39... heater, 40... gear box, 42... output shaft, 44... screw, 46... kneading disc, 50a, 50b, 50c, 50d... graph, 51a, 51b, 51c, 51d... crushing signal, 61... reference signal output unit, 62... AE signal acquisition unit, 63... AE signal analysis unit, 64... alarm unit, D... detection signal, P... point, W... AE wave

Claims

1. a waveguide rod that is disposed so as to protrude from a surface of the object to be inspected and transmits an AE signal generated in the object to be inspected; A plate attached to a tip of the waveguide rod and transmitting the AE signal; a mounting member that is screwed to a predetermined position of the plate, and into which an AE sensor that detects the AE signal is inserted so as to prevent movement of a contact position of a sensor surface of the AE sensor against the plate; a screw that is inserted into the mounting member toward a surface of the AE sensor opposite to the sensor surface and that adjusts a pressing force of the sensor surface against the plate by tightening or loosening the screw, The AE sensor is attached to the plate by tightening the screw with a preset tightening force. AE sensor mounting structure.

2. a waveguide rod that is disposed so as to protrude from a surface of the object to be inspected and transmits an AE signal generated in the object to be inspected; A plate attached to a tip of the waveguide rod and transmitting the AE signal; a mounting member that is screwed to a predetermined position of the plate, and into which an AE sensor that detects the AE signal is inserted so as to prevent movement of a contact position of a sensor surface of the AE sensor against the plate; a screw that is inserted into the mounting member toward a surface of the AE sensor opposite to a sensor surface thereof and that adjusts a pressing force of the sensor surface against the plate by tightening or loosening the screw; a signal analysis unit that detects an AE signal generated when an ultrasonic wave having a predetermined frequency is applied to the subject by the AE sensor, and calculates a magnitude of a predetermined frequency component of the AE signal; and a notification unit that issues a notification when the magnitude of the predetermined frequency component calculated by the signal analysis unit reaches a predetermined value each time the tightening force of the screw is changed. AE sensor installation support device.

3. An AE signal of a predetermined frequency is generated in the subject, The AE signal is transmitted to a waveguide rod that is installed so as to protrude from the surface of the subject and a plate that is attached to the tip of the waveguide rod, An AE sensor is screwed to a predetermined position on the plate and detects the AE signal therein. An attachment member is inserted so as to prevent the movement of the contact position of the sensor surface of the AE sensor against the plate. The fastening force of the screw is adjusted toward the surface opposite to the sensor surface of the AE sensor, thereby adjusting the pressing force of the sensor surface against the plate while adjusting the magnitude of a predetermined frequency component of the AE signal detected by the AE sensor to a predetermined value, thereby attaching the AE sensor to the plate. How to install an AE sensor.

Images