Double-groove constant-temperature bathing pool applied to insulator temperature resistance test
By using a dual-tank constant temperature bath and ultrasonic flaw detection, the high cost, high time consumption, and low efficiency of temperature resistance testing for insulator porcelain in existing technologies have been solved, enabling rapid and automated quality assessment and potential risk prediction of porcelain.
Patent Information
- Application Number
- CN202610100516.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-26
- Publication Date
- 2026-02-27
AI Technical Summary
Existing technologies cannot accurately predict the area of thermal stress concentration in insulator porcelain under temperature changes, and it is difficult to quantify the risk of microcracks caused by the difference in thermal expansion of the potting cement. In addition, traditional verification methods are costly, time-consuming, and have a high sample loss rate, requiring continuous manual monitoring, which seriously restricts the verification efficiency.
A dual-tank constant temperature bath was used for temperature resistance testing. The insulator porcelain was immersed in hot water and cold water alternately, and ultrasonic longitudinal wave, transverse wave and creeping wave flaw detection methods were used to detect internal and surface defects of the porcelain, so as to achieve rapid and automated temperature cycle testing.
It shortens the single test cycle, reduces labor costs, improves testing efficiency, can accurately assess the thermal stability and long-term service life of electrical porcelain, predict potential thermal fatigue risks, and verify the reliability of the bonding between the fittings and the porcelain body.
Smart Images
Figure CN121577477A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a constant temperature bath, and more particularly to a double-tank constant temperature bath used for insulator temperature resistance testing. Background Technology
[0002] Porcelain insulators (such as post porcelain insulators, bushings, and porcelain bottles) typically require a thermal cycling test. This test is primarily to verify their ability to resist thermal stress and fatigue damage caused by temperature changes during long-term operation. This test is one of the important items in the quality control and type testing of porcelain insulators.
[0003] In actual operation, insulator porcelain will be subjected to the following environments: extremely cold regions (temperature differences of up to tens of degrees Celsius), seasonal high and low temperature cycles, rapid temperature rise / cooling caused by power on / off of equipment, and some high-voltage equipment (such as GIS outgoing line porcelain bushings) also need to resist high-frequency local heat sources. These changes will cause the porcelain body to expand / contract, and the difference in thermal expansion and contraction at the interface between the porcelain body and metal parts and the potting cement will lead to the accumulation of internal stress → cracks → leakage / breakdown.
[0004] Existing technologies cannot accurately predict the stress concentration area at the hardware-ceramic interface, nor can they quantify the risk of microcracks caused by differences in thermal expansion of the sealing cement, making it difficult to predict the risk of thermal stress failure.
[0005] Traditional verification methods are costly, with a single test taking more than 8 hours, a sample loss rate of about 15%, and require continuous manual monitoring, which severely restricts verification efficiency. Summary of the Invention
[0006] In view of this, the present invention proposes a double-tank constant temperature bath for insulator temperature resistance testing.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: A dual-tank constant temperature bath for insulator temperature resistance testing, comprising a hot water tank and a cold water tank; the hot water tank and the cold water tank are respectively filled with hot water and cold water; a thermostat is installed in each of the hot water tank and the cold water tank; and a drain pipe is connected to the lower end of each of the hot water tank and the cold water tank. The temperature resistance test was conducted in a dual-tank constant temperature bath, including the following steps: The hot water temperature in the hot water tank is adjusted in real time to reach the set hot water temperature. First, the insulator porcelain is placed into the hot water tank and immersed in hot water for a certain period of time until the surface temperature of the insulator porcelain is the same as the set temperature of the hot water in the hot water tank. Then, the insulator porcelain is quickly taken out and immediately placed into the cold water tank and immersed in cold water for a certain period of time until the surface temperature of the insulator porcelain is the same as the set temperature of the cold water in the cold water tank. The process of the insulator porcelain going from hot to cold is calculated as one cycle, and the cycle is repeated 3 to 5 times. After the temperature resistance test is completed, the insulator porcelain is visually inspected using ultrasonic longitudinal wave, transverse wave, and creeping wave methods.
[0008] Furthermore, in step one, the hot water temperature is set to 60℃~100℃, and the cold water temperature is set to 5℃~40℃.
[0009] Furthermore, the ultrasonic longitudinal wave flaw detection, transverse wave flaw detection, and creeping wave flaw detection methods include the following steps: Step 1: Longitudinal wave flaw detection Prepare a container and place the insulator porcelain into the container. Turn on the water pump and inject room temperature water into the container at a high flow rate until the top of the insulator porcelain is submerged. Coat the front end of the first ultrasonic probe with coupling agent. The inspector holds the first ultrasonic probe, inserts it into the container, and presses it vertically and tightly against the top end face of the insulator porcelain. The first ultrasonic probe remains in place and continuously monitors the changes in the bottom wave on the oscilloscope screen. Subsequently, the first ultrasonic probe can be moved on the top end face of the insulator porcelain. Based on this principle, the longitudinal wave flaw detection process is completed at all positions on the top of the insulator porcelain. Step 2: Shear wave flaw detection Quickly drain the room temperature water, then slowly inject room temperature water into the container; install the second ultrasonic probe on the inclined surface of the wedge, and control the incident angle of the second ultrasonic probe by the inclined surface of the wedge. As the water level slowly rises, increasing by 10-20mm each time, a transverse wave detection position is reached, and the injection of room temperature water is stopped. At each transverse wave detection position, a floating component supports a wedge block floating on the water surface, and the tip of the second ultrasonic probe is immersed in the water. The second ultrasonic probe is controlled to rotate horizontally around the insulator porcelain core rod, thus performing transverse wave flaw detection on the insulator porcelain core rod at this transverse wave detection position. The waveform changes on the oscilloscope screen are continuously monitored. The transverse wave flaw detection process is completed for all transverse wave detection positions based on this principle. Step 3: Waveform Inspection Slowly and continuously drain room temperature water; install the third ultrasonic probe on the inclined surface of the wedge, and control the incident angle of the third ultrasonic probe through the inclined surface of the wedge; As the water level slowly drops, it decreases by one skirt spacing each time, reaching a creep wave detection position and stopping the discharge of room temperature water. One skirt spacing is the vertical interval between adjacent insulating skirts of the insulator porcelain. At each creep wave detection position, the floating component supports the wedge block and floats on the water surface. The front end of the third ultrasonic probe is immersed in the water. The third ultrasonic probe is controlled to perform a horizontal circular rotation around the intersection R-angle of the upper surface of the insulator porcelain skirt and the core rod. This allows for creep wave flaw detection at this creep wave detection position, and continuous monitoring of waveform changes on the oscilloscope screen. Based on this principle, the crawling wave detection process is completed for all crawling wave detection positions.
[0010] Furthermore, the first ultrasonic probe is a low-frequency longitudinal wave straight probe; the second ultrasonic probe is a water immersion transverse wave angle probe; and the third ultrasonic probe is a dual-crystal creeping wave probe.
[0011] Furthermore, in step two, when using a water-immersion shear wave angle probe to perform shear wave flaw detection on the insulator porcelain core rod, the front end of the water-immersion shear wave angle probe and the surface of the insulator porcelain core rod are always kept at a distance of 10-15 mm.
[0012] Furthermore, when using a dual-crystal creeping wave probe for creeping wave flaw detection of insulator porcelain, a distance of 2 to 5 mm needs to be maintained between the front end of the dual-crystal creeping wave probe and the junction R-angle between the upper surface of the insulator porcelain skirt and the core rod.
[0013] Furthermore, in step one, the coupling agent is an ultrasonic coupling gel.
[0014] Furthermore, in step two, the incident angle of the water immersion shear wave angle probe relative to the vertical normal is 45° to 60°; in step three, the incident angle of the dual-crystal climbing wave probe relative to the vertical normal is 20° to 25°.
[0015] Compared with existing technologies, the beneficial effects of this invention are: The single test cycle is shortened, labor costs are significantly reduced, and testing efficiency is improved; it can also be used for temperature cycling tests of similar products. The first ultrasonic probe performs longitudinal wave flaw detection on the insulator porcelain. The longitudinal wave emitted by the first ultrasonic probe propagates to the entire interior of the porcelain, and can detect pores, delamination parallel to the surface, etc. The second ultrasonic probe performs transverse wave flaw detection on the insulator porcelain. The transverse wave emitted by the second ultrasonic probe propagates to a specific angle section inside the porcelain, and can detect defects and cracks on the surface and near the surface of the inner or outer wall of the porcelain. The third ultrasonic probe performs creeping wave flaw detection on the insulator porcelain. The creeping wave emitted by the third ultrasonic probe propagates to the surface and near the surface of the porcelain, and can detect microcracks on the surface or near the surface of the porcelain. Finally, waveform characteristic analysis was used to verify the thermal stability of the electrical porcelain, observe whether the electrical porcelain can withstand frequent alternation of hot and cold, and reflect the quality of the porcelain body and the level of internal stress control; verify the reliability of the connection between the hardware and the porcelain body to prevent cracking, porcelain falling off and other phenomena, and check whether there is a hidden danger of stress concentration at the interface of the potting cement or adhesive; assess the long-term service life and help predict whether the electrical porcelain products will have the risk of thermal fatigue leading to a decline in insulation performance during decades of actual service. Attached Figure Description
[0016] Figure 1 A perspective view of a double-cell constant-temperature bath used for insulator temperature resistance testing, provided in an embodiment of the present invention; Figure 2 This is a perspective view of the insulator porcelain provided in an embodiment of the present invention.
[0017] In the diagram: 1. Hot water tank; 2. Cold water tank; 3. Insulator porcelain; 4. Drain pipe. Detailed Implementation
[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] The following describes a double-tank constant temperature bath for insulator temperature resistance testing according to the present invention, with reference to specific embodiments. Example
[0020] like Figure 1-2 As shown, a double-tank constant temperature bath is used for insulator temperature resistance testing. The double-tank constant temperature bath is divided into a hot water tank 1 and a cold water tank 2. The hot water tank 1 and the cold water tank 2 are respectively filled with hot water and cold water.
[0021] Thermostats are installed in both the hot water tank 1 and the cold water tank 2; wireless patch temperature sensors are mounted on the insulating surface of the insulator porcelain 3. The output of the wireless patch temperature sensors is electrically connected to the input of the PLC controller. The thermostats monitor the temperature of the hot water in the hot water tank 1 and the temperature of the cold water in the cold water tank 2. The thermostats control the on / off operation of the heating device in the hot water tank 1 to adjust the water temperature in real time, ensuring a temperature difference accurate to within 1°C. The thermostats also control the on / off operation of the cooling device in the cold water tank 2 to adjust the water temperature in real time, ensuring a temperature difference accurate to within 1°C.
[0022] The lower ends of hot water tank 1 and cold water tank 2 are connected to a drain pipe. A solenoid valve is installed on the drain pipe 4 (the thermostat, solenoid valve, heating device, and refrigeration device are not shown in the diagram; the thermostat, solenoid valve, heating device, and refrigeration device all use conventional products and installation methods). The input terminal of the solenoid valve is electrically connected to the output terminal of the PLC controller.
[0023] The temperature resistance test was conducted in a dual-tank constant temperature bath, including the following steps: Adjust the hot water temperature in the hot water tank 1 in real time to reach the set hot water temperature, which is 60℃~100℃. First, put the insulator porcelain 3 into the hot water tank 1 and immerse it in hot water for a certain period of time until the surface temperature of the insulator porcelain 3 is the same as the set hot water temperature in the hot water tank 1. Within 30 seconds, take out the insulator porcelain 3 and immediately put it into the cold water tank 2 and immerse it in cold water, which is 5℃~40℃. Immerse it for a certain period of time until the surface temperature of the insulator porcelain 3 is the same as the set cold water temperature in the cold water tank 2. The above-mentioned process of heating to cooling the insulator porcelain is calculated as one cycle, and the cycle is repeated 3 to 5 times. After the temperature resistance test is completed, the appearance of the insulator porcelain 3 is inspected using ultrasonic longitudinal wave flaw detection, transverse wave flaw detection, and creeping wave flaw detection methods.
[0024] After the temperature resistance test is completed, the ultrasonic longitudinal wave flaw detection, transverse wave flaw detection, and creeping wave flaw detection methods include the following steps: Step 1: Longitudinal wave flaw detection Prepare a container and place the insulator porcelain into the container. Turn on the water pump and inject room temperature water into the container at a high flow rate until the top of the insulator porcelain 3 is submerged. Coat the front end of the low-frequency longitudinal wave straight probe with coupling agent. The inspector holds a low-frequency longitudinal wave straight probe, inserts it into the container, and presses it vertically and tightly against the top end face of the insulator porcelain 3. The low-frequency longitudinal wave straight probe remains in place, and the changes in the bottom wave on the oscilloscope screen are continuously monitored to determine whether the insulator porcelain 3 is broken. Subsequently, the low-frequency longitudinal wave straight probe can be moved on the top end face of the insulator porcelain 3. Based on this principle, the longitudinal wave flaw detection process is completed at all positions on the top of the insulator porcelain 3. The coupling agent is an ultrasonic coupling gel.
[0025] Step 2: Shear wave flaw detection Quickly drain the room temperature water, then slowly pour room temperature water into the container, allowing the water level to rise from the bottom of the container; install the water immersion shear wave angle probe on the inclined surface of the wedge, and control the incident angle of the water immersion shear wave angle probe by controlling the inclined surface of the wedge; the incident angle of the water immersion shear wave angle probe relative to the vertical normal is 45°~60°. As the water level slowly rises, increasing by 10-20mm each time, a transverse wave detection position is reached, and the injection of room temperature water is stopped; ensuring a stable water surface; at each transverse wave detection position, a wedge with a water-immersed transverse wave angle probe is placed on a floating component, which supports the water-immersed transverse wave angle probe to float on the water surface, with the front end of the water-immersed transverse wave angle probe immersed in the water. The water-immersed transverse wave angle probe is controlled to rotate horizontally around the core rod of the insulator porcelain 3, so that the porcelain core rod at this transverse wave detection position can be inspected for transverse wave defects. The waveform changes on the oscilloscope screen are continuously monitored to determine whether there are pores / cracks inside the porcelain core rod. Based on this principle, the transverse wave flaw detection process is completed for all transverse wave detection positions. When the water level completely submerges the top of the electric porcelain, the internal volume of the electric porcelain is fully covered and scanned. When using a water immersion transverse wave angle probe to perform transverse wave flaw detection on the electric porcelain core rod, the front end of the water immersion transverse wave angle probe should always maintain a distance of 10-15mm from the surface of the electric porcelain core rod.
[0026] Step 3: Waveform Inspection Slowly and continuously drain room temperature water to lower the water level in the container, keeping the water level drop evenly and the water surface stable; install the dual-crystal climbing wave probe on the inclined surface of the wedge, and control the incident angle of the dual-crystal climbing wave probe by controlling the inclined surface of the wedge; the incident angle of the dual-crystal climbing wave probe with respect to the vertical normal is 20° to 25°. As the water level slowly decreases, it drops by one skirt spacing each time, reaching a creeping wave detection position and stopping the discharge of room temperature water. One skirt spacing is the vertical interval between adjacent insulating skirts of the insulator porcelain 3. At each creeping wave detection position, a wedge with a dual-crystal creeping wave probe is placed on a floating component. The floating component supports the dual-crystal creeping wave probe, which floats on the water surface. The front end of the dual-crystal creeping wave probe is immersed in the water. The dual-crystal creeping wave probe is controlled to perform a horizontal circular rotation around the junction R-angle between the upper surface of the insulator porcelain 3's skirt and the core rod. This allows for creeping wave flaw detection at the junction R-angle between the upper surface of the porcelain skirt and the core rod at this creeping wave detection position. The waveform changes on the oscilloscope screen are continuously monitored to determine whether there are defects at the junction R-angle between the upper surface of the porcelain skirt and the core rod. Based on this principle, the crawling wave testing process is completed at all crawling wave detection positions. When the water is drained, the surface at the junction R-angle between the upper surface of the electric porcelain umbrella skirt and the core rod is fully covered by scanning, and the test ends. When using a dual-crystal crawling wave probe for electric porcelain crawling wave testing, a distance of 2 to 5 mm needs to be maintained between the front end of the dual-crystal crawling wave probe and the junction R-angle between the upper surface of the electric porcelain umbrella skirt and the core rod.
[0027] The low-frequency longitudinal wave straight probe performs longitudinal wave flaw detection on the insulator porcelain 3, which can detect deeper gaps. The longitudinal wave emitted by the low-frequency longitudinal wave straight probe propagates to the entire interior of the insulator porcelain 3, and is used to detect pores, parallel surface cracks, etc. inside the insulator porcelain 3. The water-immersion shear wave angle probe performs shear wave flaw detection on the insulator porcelain 3. The detection depth is not as deep as that of longitudinal waves. The shear wave emitted by the water-immersion shear wave angle probe propagates to a specific angle section inside the insulator porcelain 3, and is used to detect defects, cracks, etc. on the surface and near the surface of the inner or outer wall of the insulator porcelain 3. The dual-crystal creeping wave probe performs creeping wave flaw detection on the insulator porcelain 3. The detection depth is shallow. The creeping wave emitted by the dual-crystal creeping wave probe propagates to the surface and near the surface of the insulator porcelain 3, and is used to detect micro-cracks on the surface or near the surface of the insulator porcelain 3.
[0028] Steps 2, 3, and 4 involve continuous monitoring of the waveform changes on the oscilloscope screen. In step 2, during the monitoring period, if the bottom wave at the corresponding full-length sound path of the insulator porcelain 3 on the oscilloscope screen remains present and the amplitude is stable, it is determined that the longitudinal structure of the insulator porcelain 3 is intact; if the bottom wave disappears or the sound path is significantly shortened and a new high-amplitude blocking wave appears, it is determined that the insulator porcelain 3 has undergone a transverse fracture.
[0029] In step three, during the monitoring period, if the baseline of the oscilloscope screen is straight and there is no obvious reflection signal, it is determined that the internal medium of the insulator porcelain 3 is continuous and uniform; if discrete pulse reflection waves appear within a specific depth range of the time baseline and the amplitude exceeds the preset threshold, it is determined that there are pores or internal cracks at the corresponding depth of the insulator porcelain 3.
[0030] In step four, during the monitoring period, if the oscilloscope screen only displays the initial wave without any subsequent signal, it is determined that the surface of the insulator porcelain 3 is intact; if a high signal-to-noise ratio reflected wave peak appears in the near field region, it is determined that there is a surface opening crack at the junction R-angle between the upper surface of the insulator porcelain 3's skirt and the core rod.
[0031] Table 1 shows the waveform characteristics on the screen during the longitudinal wave flaw detection step two. Table 2 shows the waveform characteristics on the screen during step three, transverse wave flaw detection. Table 3 shows the waveform characteristics on the screen during step four, the climbing wave flaw detection. The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A double-tank constant-temperature bath applied to temperature resistance test of insulators, characterized in that, The double-tank constant-temperature bath is provided with a hot water tank and a cold water tank, and the hot water tank and the cold water tank are respectively provided with a temperature controller. The temperature resistance test is carried out in the double-tank constant-temperature bath, and the test comprises the following steps: The water temperature in the hot water tank is adjusted in real time, and the water temperature reaches the hot water setting temperature; the insulator porcelain is first put into the hot water tank and immersed in hot water, and the immersion time is until the surface temperature of the insulator porcelain is the same as the hot water setting temperature in the hot water tank; the insulator porcelain is quickly taken out and immediately put into the cold water tank and immersed in cold water, and the immersion time is until the surface temperature of the insulator porcelain is the same as the cold water setting temperature in the cold water tank; The insulator porcelain is heated to the cold process, and one cycle is calculated, and the cycle is repeated for 3-5 times; After the temperature resistance test is completed, the insulator porcelain is subjected to appearance inspection by using ultrasonic longitudinal wave detection, transverse wave detection and creeping wave detection methods.
2. The double-tank constant-temperature bath for temperature resistance test of insulators according to claim 1, characterized in that, In the step one, the hot water setting temperature is 60-100 DEG C, and the cold water setting temperature is 5-40 DEG C.
3. The double-tank constant-temperature bath for temperature resistance test of insulators according to claim 1, characterized in that, The ultrasonic longitudinal wave detection, transverse wave detection and creeping wave detection methods comprise the following steps: Step one: longitudinal wave detection A container is prepared, and the insulator porcelain is put into the container; a water pump is started, and normal temperature water is injected into the container at a large flow rate until the top end of the insulator porcelain is submerged; the front end of a first ultrasonic probe is coated with a coupling agent; A detection personnel holds the first ultrasonic probe, and the first ultrasonic probe is inserted into the container and vertically pressed and closely attached to the top end face of the insulator porcelain; the first ultrasonic probe remains in position, and the bottom wave change on the oscilloscope screen is continuously monitored; the first ultrasonic probe can be moved on the top end face of the insulator porcelain, and the longitudinal wave detection process of all positions of the top end of the insulator porcelain is completed according to the principle; Step two: transverse wave detection The normal temperature water is quickly emptied, and then normal temperature water is slowly injected into the container; a second ultrasonic probe is installed on the inclined surface of a wedge, and the incident angle of the second ultrasonic probe is controlled through the inclined surface of the wedge; With the slow rising of the water level, the water level is raised by 10-20 mm each time, and the normal temperature water injection is stopped when a transverse wave detection position is reached; at each transverse wave detection position, the wedge is floated on the water surface by the floating member, the front end of the second ultrasonic probe is immersed in the water, and the second ultrasonic probe is controlled to make horizontal circular motion around the insulator porcelain core rod, so that the insulator porcelain core rod at the transverse wave detection position is subjected to transverse wave detection, and the waveform change on the oscilloscope screen is continuously monitored; the transverse wave detection process of all transverse wave detection positions is completed according to the principle; Step three: creeping wave detection The normal temperature water is continuously and slowly discharged; a third ultrasonic probe is installed on the inclined surface of a wedge, and the incident angle of the third ultrasonic probe is controlled through the inclined surface of the wedge; As the water level slowly drops, it decreases by one skirt spacing each time, reaching a creep wave detection position and stopping the discharge of room temperature water. One skirt spacing is the vertical interval between adjacent insulating skirts of the insulator porcelain. At each creep wave detection position, the floating component supports the wedge block and floats on the water surface. The front end of the third ultrasonic probe is immersed in the water. The third ultrasonic probe is controlled to perform a horizontal circular rotation around the intersection R-angle of the upper surface of the insulator porcelain skirt and the core rod. This allows for creep wave flaw detection at this creep wave detection position, and continuous monitoring of waveform changes on the oscilloscope screen. Based on this principle, the crawling wave detection process is completed for all crawling wave detection positions.
4. The double-tank constant-temperature bath for temperature resistance test of insulators according to claim 3, characterized in that, The first ultrasonic probe is a low-frequency longitudinal wave straight probe; the second ultrasonic probe is a water immersion transverse wave angle probe; and the third ultrasonic probe is a dual-crystal creeping wave probe.
5. The double-tank constant-temperature bath for temperature resistance test of insulators according to claim 4, characterized in that, In step two, when using a water-immersion shear wave angle probe to perform shear wave flaw detection on the insulator porcelain core rod, the front end of the water-immersion shear wave angle probe should always maintain a distance of 10-15 mm from the surface of the insulator porcelain core rod.
6. The double-tank constant-temperature bath for temperature resistance test of insulators according to claim 4, characterized in that, When using a dual-crystal creeping wave probe for creeping wave flaw detection of insulator porcelain, a distance of 2-5 mm should be maintained between the front end of the dual-crystal creeping wave probe and the junction R-angle between the upper surface of the insulator porcelain skirt and the core rod.
7. The double-tank constant-temperature bath for temperature resistance test of insulators according to claim 3, characterized in that, In step one, the coupling agent is an ultrasonic coupling gel.
8. The double-tank constant-temperature bath for temperature resistance test of insulators according to claim 4, characterized in that, In step two, the incident angle of the water immersion shear wave angle probe relative to the vertical normal is 45° to 60°; in step three, the incident angle of the dual-crystal climbing wave probe relative to the vertical normal is 20° to 25°.