A waveguide rod for acoustic emission monitoring

Abstract

The present invention discloses a waveguide rod for acoustic emission monitoring, which includes a heat dissipation rod body and conical contact device ends and contact sensor ends located at both ends of the heat dissipation rod body. A pressing ring is arranged in the middle of the heat dissipation rod body. The pressing ring includes an integrated disc and sleeve, and mounting holes are formed in the disc. A spring is arranged between the sleeve and the heat dissipation rod body. One end of the spring is limited at the connection between the heat dissipation rod body and the contact device end, and the other end is limited at the connection between the sleeve and the disc. A groove is formed at the center of the end face of the contact device end, and spiral shallow grooves are connected outward from the groove on the end face. An inclined material storage hole is formed in the upper part of the contact device end. One end of the material storage hole communicates with the groove, and the other end communicates with a ventilation hole arranged on the side surface of the contact device end. A low melting point metal rod or a low melting point alloy rod is arranged in the material storage hole. The waveguide rod disclosed by the present invention is convenient to install, has small attenuation of acoustic signals, and is suitable for long-term monitoring under high temperature conditions.

Description

Technical Field

[0001] The present invention relates to a waveguide rod, and particularly to a waveguide rod for acoustic emission monitoring. Background Art

[0002] Acoustic emission monitoring has high sensitivity and can detect the entire process of defect initiation, propagation, and fracture. It can continuously monitor and give early warnings of the generation and propagation activities of defects, and has some advantages that other non-destructive testing methods do not have, and is applied in many industrial fields. However, since the conventional piezoelectric probe has a low operating temperature, generally requiring the temperature of the measured part to be below 60°C, for high-temperature equipment, a waveguide rod is usually used to connect the probe and the measured surface.

[0003] Patent CN201555831U discloses a waveguide rod for acoustic emission detection, providing a hyperbolic gyrobody waveguide rod with fast temperature attenuation and small acoustic signal attenuation. However, it does not mention how to connect the waveguide rod to the high-temperature equipment. Usually, the waveguide rod is connected to the equipment by welding. Since welding is prone to changes in composition and structure and the introduction of various defects locally, it increases the equipment risk. For equipment in operation, the risk is even higher, and it is not easy to implement welding. Some high-temperature parts also use bundling and compaction with a high-temperature coupling agent. However, due to the volatilization of the coupling agent at high temperatures, it is only applicable to detection at lower temperatures or for a short time (<5 min), and is not suitable for long-term monitoring under such high-temperature conditions.

[0004] Patent CN202421137U discloses a connection mechanism for an acoustic emission detection sensor, a waveguide rod, and a detected object, providing a connection mechanism between the waveguide rod and the equipment, which uses the attraction of a magnet to press the waveguide rod on the measured equipment, and the connection is convenient. However, since metals are attached to each other by attraction, the attenuation of waves is large, and it can only be used for ferromagnetic substrates and cannot be used for non-magnetic or low-magnetic substrates such as austenitic stainless steel. Moreover, the magnetism is affected by temperature, and the higher the temperature, the weaker the magnetism. After the temperature is higher than the critical temperature of the material, the magnetism will also disappear. These also greatly limit the application range of this connection method. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a waveguide rod for acoustic emission monitoring, which solves the problem of wave conduction for long-term online monitoring of high-temperature equipment, so as to achieve the purpose of convenient installation, small acoustic signal attenuation, and suitability for long-term monitoring under high-temperature conditions.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A waveguide rod for acoustic emission monitoring, comprising a heat dissipation rod body and conical contact device ends and contact sensor ends located at both ends of the heat dissipation rod body. A pressing ring is arranged in the middle of the heat dissipation rod body. The pressing ring includes an integral disc and a sleeve. Mounting holes are formed in the disc. A spring is arranged between the sleeve and the heat dissipation rod body. One end of the spring is limited at the connection between the heat dissipation rod body and the contact device end, and the other end is limited at the connection between the sleeve and the disc. A groove is formed at the center of the end face of the contact device end, and spiral shallow grooves are connected outward from the groove on the end face. A storage hole is formed obliquely in the upper part of the contact device end. One end of the storage hole communicates with the groove, and the other end communicates with a vent hole arranged on the side face of the contact device end. A low melting point metal rod or a low melting point alloy rod is arranged in the storage hole.

[0008] In the above solution, the depth of the spiral shallow groove gradually becomes shallower from the center to the outside.

[0009] In the above solution, a coupling agent is coated between the end face of the contact sensor end and the sensor, and the contact sensor end and the sensor are fixed by means of winding, magnetic attraction, bonding or screw pressing.

[0010] In the above solution, the heat dissipation rod body is fixed on the equipment or pipeline through the mounting holes on the disc.

[0011] In the above solution, the material of the low melting point metal rod or the low melting point alloy rod is selected from one or a combination of tin, antimony, lead, and zinc.

[0012] In the above solution, one or more storage holes are provided, with a diameter of 1-10 mm, and the number of vent holes is the same as that of the storage holes.

[0013] In the above solution, the included angle between the storage hole and the central axis of the contact device end is 2-45°.

[0014] In the above solution, the material of the waveguide rod is selected from carbon steel or stainless steel.

[0015] In the above solution, the contact sensor end is conical.

[0016] Through the above technical solution, a waveguide rod for acoustic emission monitoring provided by the present invention has the following beneficial effects:

[0017] (1) The waveguide rod of the present invention is fixed on the equipment or pipeline through the mounting holes on the disc, and the force is transmitted to the contact device end through the spring, which can ensure the uniform and constant force, avoid a large decrease in the pressing force caused by relaxation, and then the waveguide rod is closely attached to the wall of the equipment or pipeline under the action of the force.

[0018] (2) The contact device end of the present invention is coupled with the device after the low-melting-point metal rod or low-melting-point alloy rod melts at high temperature, without the need for welding, which is convenient and simple to install, and will not cause changes in the tissue properties of the local wall of the device, introducing new risks.

[0019] (3) The waveguide rod of the present invention is coupled with the high-temperature device by liquid metal, and the attenuation of the acoustic signal is small.

[0020] (4) The present invention is applicable to long-term on-line monitoring under high-temperature conditions of 300 - 600 °C. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0022] Figure 1 Schematic diagram of a waveguide rod for acoustic emission monitoring disclosed in an embodiment of the present invention;

[0023] Figure 2 For Figure 1 the schematic diagram of the A-A cross-section in

[0024] Figure 3 For Figure 1 the schematic diagram of the B-B cross-section in

[0025] In the figure, 1. heat dissipation rod body; 2. contact device end; 3. contact sensor end; 4. disc; 5. sleeve; 6. mounting hole; 7. spring; 8. groove; 9. spiral shallow groove; 10. storage hole; 11. ventilation hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention.

[0027] The present invention provides a waveguide rod for acoustic emission monitoring, as Figure 1 shown, including a heat dissipation rod body 1 and a tapered contact device end 2 and a tapered contact sensor end 3 located at both ends of the heat dissipation rod body 1. A compression ring is provided in the middle of the heat dissipation rod body 1. The compression ring includes an integral disc 4 and a sleeve 5. A mounting hole 6 is opened on the disc 4, and the heat dissipation rod body 1 is fixed on the device or pipeline through the mounting hole 6 on the disc 4. The material of the waveguide rod is selected from carbon steel or stainless steel.

[0028] A spring 7 is provided between the sleeve 5 and the heat dissipation rod body 1. One end of the spring 7 is limited at the connection between the heat dissipation rod body 1 and the contact device end 2, and the other end is limited at the connection between the sleeve 5 and the disc 4. As Figure 3As shown, the spring 7 is located inside the sleeve 5. The inner diameter of the sleeve 5 is larger than that of the disc 4, which can hold the spring 7 in place. The function of the spring 7 is to ensure the uniform and constant force, avoid a significant decrease in the pressing force due to relaxation, and thus make the waveguide rod closely fit the wall of the device / pipeline under the action of the force.

[0029] As Figure 2 shown, a groove 8 is opened at the center of the end face of the contact device end 2. A spiral shallow groove 9 is connected outward from the groove 8 on the end face. An inclined material storage hole 10 is opened in the upper part of the contact device end 2. One end of the material storage hole 10 communicates with the groove 8, and the other end communicates with a vent hole 11 provided on the side of the contact device end 2. A low-melting-point metal rod or a low-melting-point alloy rod is arranged in the material storage hole 10. The material of the low-melting-point metal rod or the low-melting-point alloy rod is selected from one or a combination of tin, antimony, lead, and zinc. One or more material storage holes 10 are provided, with a diameter of 1 - 10 mm. The number of vent holes 11 is the same as that of the material storage holes 10. An included angle α of 2 - 45° is formed between the material storage hole 10 and the central axis of the contact device end 2.

[0030] During use, the heat from the surface of the high-temperature device / pipeline diffuses and transfers to the contact device end 2 of the waveguide rod, causing the temperature of the contact device end 2 of the waveguide rod to gradually rise. When the temperature rises above the melting point of the internal metal rod or alloy rod, the metal rod or alloy rod melts. As the low-melting-point metal gradually liquefies, the liquid metal flows into the groove 8 connected to it along the inclined material storage hole 10 under the action of gravity. The vent hole 11 ensures the air pressure balance in the material storage hole 10, facilitating the flow of the liquid metal. When necessary, a syringe or other similar tool can be used to inject air into the vent hole 11 to promote the liquid metal to flow into the spiral shallow groove 9. The liquid metal flows along the spiral shallow groove 9, fills the gap between the surface of the device / pipeline to be measured and the end face of the contact device end 2 of the waveguide rod, and realizes the coupling between the contact device end 2 of the waveguide rod and the wall of the device / pipeline.

[0031] The depth of the spiral shallow groove 9 gradually becomes shallower from the center to the outside, which can limit the outflow of the liquid metal from the end face area.

[0032] A coupling agent is coated on the end face between the contact sensor end 3 and the sensor, and the contact sensor end 3 and the sensor can be fixed by conventional methods such as winding, magnetic attraction, bonding, or screw pressing.

[0033] The contact device end 2 of the waveguide rod can be set into an arc shape with the same curvature according to the size and shape of the device / pipeline to be monitored, which can better fit the surface of the device and also prevent the liquid metal from flowing out of the contact surface.

[0034] During the monitoring process, after the acoustic signal from the equipment / pipeline diffuses to the surface, it enters the liquid metal through the interface between the metal equipment / pipeline and the liquid metal. The sound wave propagates in the liquid metal. When it reaches the interface of the contact equipment end 2 of the liquid metal and the waveguide rod, refraction and reflection occur again. The sound wave enters the waveguide rod. Subsequently, the sound wave is transmitted to the contact sensor end 3 of the waveguide rod through the heat dissipation rod body 1 of the waveguide rod, and then passes through the interface between the waveguide rod and the coupling agent, and the interface between the coupling agent and the sensor in sequence to reach the sensor. After piezoelectric conversion, an induced signal is obtained.

[0035] Example 1

[0036] The waveguide rod of the present invention is used to monitor the residue hydrotreating reactor. The residue hydrotreating reactor has a diameter of 5600 mm, a wall thickness of 344 mm, and a wall temperature of 400 °C. Therefore, a waveguide rod made of 304L stainless steel is selected, and the low melting point alloy is selected as lead, tin, antimony alloy (80%, 15%, 3%). The low melting point lead-tin alloy rod is inserted into the storage holes 10 provided at the contact equipment end 2 of the waveguide rod. There are two storage holes 10, which are inclined at an angle of 15° to the axis, with a pore diameter of 6 mm. The inner end of the storage hole 10 is connected to the vent hole 11, and there are also two vent holes 11. One end on the surface converges to the groove 8 at the contact equipment end 2 of the waveguide rod. The depth of the groove 8 is 4 mm, and the spiral shallow groove 9 is connected to the middle groove 8. The iron wire passes through the mounting hole 6 on the disc 4 of the compression ring, and the other end is directly fixed to the reactor insulation through a screw. The compression ring presses the spring 7 installed between the sleeve 5 of the compression ring and the heat dissipation rod body 1. The heat dissipation rod body 1 passes through the sleeve 5 of the compression ring and the spring 7, and the force is transmitted to the contact equipment end 2 of the waveguide rod through the spring 7. Under the action of the pressing force, the waveguide rod is closely attached to the wall of the equipment / pipeline. The contact equipment end 2 of the waveguide rod is connected to the contact sensor end 3 of the waveguide rod through the heat dissipation rod body 1, and the length of the heat dissipation rod body 1 is 280 mm. After applying an appropriate amount of coupling agent to the sensor end face, it is attached and fixed to the contact sensor end 3 of the waveguide rod. The fixing method is selected as the thread pressing method.

[0037] During operation, the heat from the reactor surface diffuses and transfers to the contact device end 2 of the waveguide rod, causing the temperature of the contact device end 2 to gradually rise. When the temperature rises above 400 °C, the alloy begins to melt. As the low-melting-point metal gradually liquefies, the liquid metal flows along the inclined storage hole 10 under the action of gravity and into the groove 8 connected to it. The liquid metal flows along the spiral shallow groove 9, fills the gap between the surface of the device / pipeline to be measured and the contact device end 2, and realizes the coupling between the contact device end 2 and the wall of the device / pipeline. The spiral shallow groove 9 gradually becomes shallower from the inside (center) to the outside, with a maximum depth of 4 mm, restricting the liquid metal from flowing out of the end face area of the contact device end 2. During the monitoring process, after the acoustic signal from the device / pipeline diffuses to the surface, it passes through the interface between the metal device / pipeline and the liquid metal and enters the liquid metal. The acoustic wave propagates in the liquid metal. When it reaches the interface between the liquid metal and the contact device end 2, refraction and reflection occur again. The acoustic wave enters the inside of the waveguide rod, and then is transmitted to the contact sensor end 3 of the waveguide rod through the heat dissipation rod body 1 of the waveguide rod. Then, it passes through the interfaces between the waveguide rod and the coupling agent, and between the coupling agent and the sensor in sequence to reach the sensor. After piezoelectric conversion, an induced signal is obtained, and then it enters the acquisition, storage, and processing system through an amplifier.

[0038] Embodiment 2:

[0039] The first regenerator of a fluid catalytic cracking unit is monitored using the waveguide rod of the present invention. The regenerator has a diameter of 6800 mm, a wall thickness of 24 mm, an internal operating temperature of 700 °C, and the normal wall temperature is 200 - 300 °C. When the internal heat insulation lining is damaged and falls off, the local temperature may exceed 500 °C. In this embodiment, a carbon steel waveguide rod is selected, and the low-melting-point alloy is a tin-lead alloy (63%, 37%). The low-melting-point lead-tin alloy rod is inserted into the storage hole 10 provided at the contact device end 2 of the waveguide rod. There are 3 storage holes 10, with an inclined angle of 20° with the axis, a hole diameter of 5 mm. The inner end of the storage hole 10 is connected to the ventilation hole 11, and there are also 3 ventilation holes 11. One end of the surface converges to the groove 8 at the contact device end 2 of the waveguide rod. The groove 8 has a depth of 4 mm, and the spiral shallow groove 9 is connected to the groove 8. The iron wire passes through the mounting hole 6 on the disc 4 of the compression ring, and the other end is directly fixed to the reactor insulation through a screw. The compression ring applies force to compress the spring 7 installed between the sleeve 5 of the compression ring and the heat dissipation rod body 1. The heat dissipation rod body 1 passes through the sleeve 5 of the compression ring and the spring 7, and transfers the force to the contact device end 2 of the waveguide rod through the spring 7. Under the action of the pressing force, the waveguide rod is closely attached to the wall of the device / pipeline. The contact device end 2 of the waveguide rod is connected to the contact sensor end 3 of the waveguide rod through the heat dissipation rod body 1, and the length of the heat dissipation rod body 1 is 310 mm. After applying an appropriate amount of coupling agent to the sensor end face, it is attached and fixed to the contact sensor end 3 of the waveguide rod. The fixing method is selected as the threaded compression method.

[0040] During operation, the heat from the reactor surface diffuses and transfers to the contact device end 2 of the waveguide rod, causing the temperature of the contact device end 2 to gradually rise. When the temperature rises above 200 °C, the alloy begins to melt. As the low-melting-point metal gradually liquefies, the liquid metal flows along the inclined storage hole 10 under the action of gravity and into the groove 8 connected to it. The liquid metal flows along the spiral shallow groove 9, fills the gap between the surface of the device / pipeline to be measured and the contact device end 2, and realizes the coupling between the contact device end 2 and the wall of the device / pipeline. The spiral shallow groove 9 gradually becomes shallower from the inside (center) to the outside, with a maximum depth of 4 mm, restricting the liquid metal from flowing out of the end face area of the contact device end 2. During the monitoring process, after the acoustic signal from the device / pipeline diffuses to the surface, it enters the liquid metal through the interface between the metal device / pipeline and the liquid metal. The acoustic wave propagates in the liquid metal. When it reaches the interface between the liquid metal and the contact device end 2, refraction and reflection occur again. The acoustic wave enters the waveguide rod, and then is transmitted to the contact sensor end 3 of the waveguide rod through the heat dissipation rod body 1 of the waveguide rod. Then, it passes through the interfaces between the waveguide rod and the coupling agent, and between the coupling agent and the sensor in sequence to reach the sensor. After piezoelectric conversion, an induced signal is obtained, and then it enters the acquisition, storage, and processing system through an amplifier.

[0041] Example 3:

[0042] The second regenerator of the fluid catalytic cracking unit is monitored using the waveguide rod of the present invention. The regenerator has a diameter of 5800 mm, a wall thickness of 24 mm, an internal temperature of 700 °C, and the normal wall temperature is 200 - 300 °C. When the internal heat insulation lining is damaged and falls off, the local temperature may exceed 500 °C. A carbon steel waveguide rod is selected, and the low-melting-point alloy is tin-lead alloy (63%, 37%). The low-melting-point lead-tin alloy rod is inserted into the storage hole 10 provided at the contact device end 2 of the waveguide rod. There are 2 storage holes 10, with an inclination angle of 30° with respect to the axis, a pore diameter of 4 mm. The inner end of the storage hole 10 is connected to the ventilation hole 11, and there are also 2 ventilation holes 11. One end on the surface converges to the groove 8 at the contact device end 2 of the waveguide rod. The groove 8 has a depth of 4 mm, and the spiral shallow groove 9 is connected to the groove 8. The iron wire passes through the mounting hole 6 on the disc 4 of the compression ring, and the other end is directly fixed to the reactor insulation through a screw. The compression ring is stressed to compress the spring 7 installed between the sleeve 5 of the compression ring and the heat dissipation rod body 1. The heat dissipation rod body 1 passes through the sleeve 5 of the compression ring and the spring 7, and the force is transmitted to the contact device end 2 of the waveguide rod through the spring 7. Under the action of the pressing force, the waveguide rod is closely attached to the wall of the device / pipeline. The contact device end 2 of the waveguide rod is connected to the contact sensor end 3 of the waveguide rod through the heat dissipation rod body 1, and the length of the heat dissipation rod body 1 is 350 mm. After applying an appropriate amount of coupling agent to the sensor end face, it is attached and fixed to the contact sensor end 3 of the waveguide rod. The fixing method is selected as the threaded pressing method.

[0043] During operation, the heat from the reactor surface diffuses and transfers to the contact device end 2 of the waveguide rod, causing the temperature of the contact device end 2 to gradually rise. When the temperature rises above 200 °C, the alloy begins to melt. As the low-melting-point metal gradually liquefies, the liquid metal flows along the inclined storage hole 10 under the action of gravity and into the groove 8 connected thereto. The liquid metal flows along the spiral shallow groove 9, fills the gap between the surface of the device / pipeline to be measured and the contact device end 2, and realizes the coupling between the contact device end 2 and the wall of the device / pipeline. The spiral shallow groove 9 gradually becomes shallower from the inside (center) to the outside, with a maximum depth of 3 mm, restricting the liquid metal from flowing out of the end face area of the contact device end 2. During the monitoring process, after the acoustic signal from the device / pipeline diffuses to the surface, it passes through the interface between the metal device / pipeline and the liquid metal and enters the liquid metal. The acoustic wave propagates in the liquid metal. When it reaches the interface between the liquid metal and the contact device end 2, refraction and reflection occur again. The acoustic wave enters the inside of the waveguide rod, and then the acoustic wave is transmitted to the contact sensor end 3 of the waveguide rod through the heat dissipation rod body 1 of the waveguide rod. Then, it successively passes through the interface between the waveguide rod and the coupling agent, and the interface between the coupling agent and the sensor to reach the sensor. After piezoelectric conversion, an induced signal is obtained, and then it enters the acquisition, storage, and processing system through the amplifier.

[0044] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A waveguide rod for acoustic emission monitoring, characterized in that, It includes a heat dissipation rod body, and conical contact device ends and contact sensor ends located at both ends of the heat dissipation rod body. A pressing ring is arranged in the middle of the heat dissipation rod body. The pressing ring includes an integral disc and a sleeve. The inner diameter of the sleeve is larger than the inner diameter of the disc. Mounting holes are formed in the disc. A spring is arranged between the sleeve and the heat dissipation rod body. One end of the spring is limited at the connection between the heat dissipation rod body and the contact device end, and the other end is limited at the connection between the sleeve and the disc. A groove is formed at the center of the end face of the contact device end, and spiral shallow grooves are connected outward from the groove on the end face. The depth of the spiral shallow grooves gradually becomes shallower from the center to the outside. An inclined storage hole is formed in the upper part of the contact device end. One end of the storage hole communicates with the groove, and the other end communicates with a ventilation hole arranged on the side surface of the contact device end. A low-melting-point metal rod or a low-melting-point alloy rod is arranged in the storage hole.

2. The waveguide rod for acoustic emission monitoring according to claim 1, wherein A coupling agent is coated between the end face of the contact sensor end and the sensor, and the contact sensor end and the sensor are fixed by means of winding, magnetic attraction, bonding or screw pressing.

3. The waveguide rod for acoustic emission monitoring according to claim 1, characterized in that, The heat dissipation rod body is fixed on the device or pipeline through the mounting holes in the disc.

4. A waveguide rod for acoustic emission monitoring according to claim 1, characterized in that, The low-melting-point metal rod or the low-melting-point alloy rod is made of one or a combination of tin, antimony, lead, and zinc.

5. A waveguide rod for acoustic emission monitoring according to claim 1, characterized in that, One or more storage holes are provided, with a diameter of 1-10 mm, and the number of ventilation holes is the same as that of the storage holes.

6. A waveguide rod for acoustic emission monitoring according to claim 1 or 5, characterized in that, The included angle between the storage hole and the central axis of the contact device end is 2-45°.

7. A waveguide rod for acoustic emission monitoring according to claim 1, characterized in that, The waveguide rod is made of carbon steel or stainless steel.

8. A waveguide rod for acoustic emission monitoring according to claim 1, characterized in that, The contact sensor end is conical.

Images