A kind of climatic ageing test device for direct current surge arrester

Abstract

The present application relates to the technical field of corrosion test, and discloses a kind of weathering test device for DC arrester, including the test box body with sealed box door and the environmental simulation system in box body, sample bearing system, electrical loading and monitoring system and control system.Sample bearing system uses rigid chain drive drive at one end, and elastic floating abutting structure at one end: each drive spindle of drive end is meshed with driving sprocket to realize synchronous rotation through same closed loop chain, and fast change self-adapting jaw is arranged at shaft end;Floating end floating short shaft can be axially slid through linear bearing, and pre-tightening force is continuously applied by adjustable axial elastic abutting device to compensate thermal expansion and cold shrinkage of sample;V-shaped elastic follow-up supporting roller is vertically supported in the middle.Fast change self-adapting jaw converts axial thrust into radial holding force through taper surface cooperation.The present application solves the problem of additional stress generated by thermal expansion and cold shrinkage in temperature cycle of horizontal long shaft sample, realizes multi-station synchronous rotation, fast clamping and uniform environment field.

Description

Technical Field

[0001] This invention relates to the technical field of corrosion testing, and more particularly to a climate aging test apparatus for DC surge arresters. Background Technology

[0002] Climate testing equipment is a test device used to simulate various natural environmental conditions. By controlling environmental parameters such as temperature, humidity, salt spray, and ultraviolet radiation in a sealed chamber, it conducts accelerated aging or weathering tests on samples to evaluate the performance stability and service life of products under complex climatic environments. It is widely used in product reliability verification in the fields of electronics, power, and materials.

[0003] Patent CN122130591A discloses a paper product climate environment simulation test chamber, which includes a simulation test chamber body composed of a spraying device and a heating device installed on the test chamber body. The test chamber body is also provided with a support structure for placing paper products. The support structure includes a support platform, a clamp set on the support platform, and a base set below the support platform. A slider that slides with the base is fixed on the bottom side of the support platform. The base is provided with a return spring connected to the slider.

[0004] The existing technology has the following drawbacks: DC surge arresters must undergo climate aging tests before being put into actual operation to verify their long-term performance stability under the combined effects of temperature and humidity cycling, salt spray corrosion, and ultraviolet radiation. Existing climate aging test equipment typically uses a clamping method with both ends fixed when testing horizontally placed long-axis surge arrester samples. The samples are rigidly positioned at both ends. When the test temperature changes significantly, the axial expansion and contraction deformation of the sample due to thermal expansion and contraction is constrained, resulting in additional axial and bending stresses inside the sample. Long-term accumulation of these stresses may lead to sample deformation or internal structural damage, affecting the accuracy of the test results.

[0005] Furthermore, in existing multi-station testing, the rotation drive of each specimen is often independent, making it difficult to ensure strict synchronization. This leads to differences in the environmental exposure conditions received by different specimens, reducing the comparability of test data. Specimen clamping often uses bolt fastening, which is cumbersome, inefficient in replacement, and difficult to precisely control the clamping force. In long-term corrosive environments, electrical contact points are prone to increased contact resistance or even poor contact. For long-length specimens, existing intermediate support structures are mostly fixed brackets with sliding friction between the specimen and the support. This not only hinders axial micro-slippage caused by thermal deformation but also easily causes surface wear. Meanwhile, the sealing structure at the point where the rotating shaft penetrates the chamber wall is prone to seal failure under long-term exposure to corrosive media such as salt spray, leading to the leakage of corrosive gases and affecting the reliability of equipment operation. Summary of the Invention

[0006] In view of the above-mentioned problems in the existing technology, a climate aging test device for DC surge arresters is proposed.

[0007] One aspect of this application provides a climate aging test device for DC surge arresters, the purpose of which is to solve the technical problems of existing climate aging test devices that use rigid clamping at both ends for horizontal long-axis DC surge arrester samples, which restricts the axial deformation of the samples caused by thermal expansion and contraction during temperature cycling tests, thereby causing additional stress and bending deformation. At the same time, there are also technical problems such as asynchronous rotation at multiple stations, low clamping efficiency, unreliable electrical contact and sealing failure at the penetration box wall.

[0008] The technical solution of the present invention is: a climate aging test device for DC surge arresters, comprising a test chamber with a sealed door, an environmental simulation system disposed inside the test chamber, a sample carrying system, an electrical loading and monitoring system, and a control system connected to each system; The sample carrying system includes multiple sets of rotating support positions arranged side by side along the horizontal direction. Each set of rotating support positions corresponds to a horizontally placed DC surge arrester sample. The sample carrying system includes: The drive end assembly is located on one side of the test chamber and includes multiple drive spindles arranged in parallel along a vertical plane. Each drive spindle has a driven sprocket fixedly sleeved on its shaft end inside the test chamber. All driven sprockets are meshed with the driving sprocket through the same closed-loop chain. The driving sprocket is driven to rotate by a servo motor. Each drive spindle has a quick-change adaptive gripper on its shaft end inside the test chamber. A floating end assembly, located on the other side of the test chamber and opposite to the drive end assembly, includes multiple floating short shafts. Each floating short shaft is axially slidably mounted on a fixed support via a linear bearing. Each floating short shaft has a quick-change adaptive gripper at the end closest to the sample and an adjustable axial elastic clamping device at the end furthest from the sample. The elastic clamping device continuously applies an axial preload towards the sample to the floating short shaft. An intermediate support assembly is disposed between the drive end assembly and the floating end assembly, comprising multiple sets of V-shaped elastic follower rollers arranged at intervals along the axial direction of each sample. Each set of V-shaped elastic follower rollers provides vertical support to the sample and passively rolls as the sample rotates. The quick-change adaptive gripper includes a fixed conical sleeve and multiple elastic grippers evenly distributed along the circumference. The outer wall of the elastic gripper is a conical surface and slides in cooperation with the inner conical surface of the fixed conical sleeve. The inner wall of the elastic gripper is provided with an electrical contact structure. The elastic gripper relies on axial thrust to radially contract to grip or release the end of the sample. The electrical loading and monitoring system includes a rotating conductive slip ring disposed on the outside of the test chamber and connected to each of the drive main shafts or floating short shafts. A dynamic sealing structure is provided between the drive end assembly and the floating end assembly and the chamber wall of the test chamber.

[0009] Furthermore, the axial elastic clamping device includes: An adjusting nut is provided at the end of the floating short shaft that extends out of the fixed support; A thrust bearing is disposed between the adjusting nut and the fixed support; A compression spring is fitted onto the floating short shaft and located between the fixed support and the thrust bearing. One end of the compression spring abuts against the end face of the fixed support, and the other end abuts against the adjusting nut through the thrust bearing. The amount of compression of the compression spring is changed by rotating the adjusting nut, thereby adjusting the magnitude of the axial preload applied to the sample.

[0010] Furthermore, the fixed cone sleeve of the quick-change adaptive gripper is detachably connected to the shaft end of the drive spindle via a spline pair or a square tapered shank; a radial return spring coil is provided at the root of the elastic gripper, so that each elastic gripper is in an open state when not subjected to axial pressure; the electrical contact structure is an annular sawtooth contact rib extending along the circumferential direction of the inner wall of the elastic gripper, and the surface of the contact rib is provided with a silver plating layer or a gold plating layer; the roots of each elastic gripper are connected in parallel via a flexible conductive strip.

[0011] Furthermore, the outer wall of the elastic gripper is provided with a protruding ridge for limiting sliding, the inner conical surface of the fixed conical sleeve is provided with a limiting groove that cooperates with the protruding ridge, and a limiting ring is provided at the opening of the inner conical surface of the fixed conical sleeve to prevent the elastic gripper from falling out.

[0012] Furthermore, the V-shaped elastic follower roller includes two longitudinally horizontally arranged driven rollers, the rotation axes of the two driven rollers are parallel to the sample axis, the two driven rollers are symmetrically inclined in a figure-eight shape in the transverse section, and the outer walls of the two driven rollers together form a V-shaped support groove; the surface of each driven roller is provided with a diamond knurled or herringbone knurled structure; the two ends of each driven roller are mounted on a bearing seat through rolling bearings, and a disc spring buffer seat is provided at the bottom of the bearing seat, so that the driven roller has a vertical floating stroke.

[0013] Furthermore, the environmental simulation system includes a temperature and humidity control module, a salt spray generation module, an ultraviolet irradiation module, and a circulating air duct module. The salt spray generation module sprays salt spray in a horizontal direction and perpendicular to the axis of each sample. The test chamber has an air inlet guide structure and an air return collection structure on its opposite side walls. The air inlet guide structure is connected to the salt spray generation module, and the air return collection structure is connected to the return air inlet of the circulating fan.

[0014] Furthermore, the air inlet guiding structure includes multiple vertically arranged rotatable arc-shaped guiding blades. Each arc-shaped guiding blade is connected by a linkage mechanism and its angle can be adjusted synchronously to uniformly distribute the salt spray airflow along the vertical direction to the height range of each sample. The return air collecting structure includes a gradually expanding collecting hood and a porous flow equalization damping plate disposed on the air inlet side of the gradually expanding collecting hood. The opening ratio of the porous flow equalization damping plate increases from the center to the edge.

[0015] Furthermore, the dynamic sealing structure of the drive end assembly includes a multi-stage sawtooth annular groove disposed on the outer wall of the drive spindle, and a sealing seat fixedly disposed on the housing wall. The inner wall of the sealing seat is provided with annular protrusions that interlock with the annular groove. The sealing seat and the drive spindle or the floating short shaft form a labyrinth sealing channel. At least one air inlet microhole is evenly distributed along the circumferential direction at the middle position of the sealing seat. Each air inlet microhole is connected to an external positive pressure inert gas source to form an annular positive pressure air curtain in the labyrinth sealing channel.

[0016] Furthermore, the dynamic sealing structure of the floating end assembly is a metal bellows sealing assembly. One end of the metal bellows is welded to the outer wall of the floating short shaft, and the other end is welded to the fixed support or the box wall. The metal bellows extends and retracts as the floating short shaft slides axially. A nitrogen purging port is provided on the outer side of the metal bellows.

[0017] Furthermore, the control system includes a PLC controller and a touch screen operation panel. The test chamber is equipped with a temperature sensor, a humidity sensor, a salt spray concentration sensor, and an ultraviolet radiation intensity sensor. Each of the drive spindles or floating short shafts is equipped with a leakage current sensor corresponding to each sample. The signal lines of each leakage current sensor are led out to the control system through the rotating conductive slip ring. The control system also includes a frequency converter connected to the servo motor and a rotary encoder connected to the drive sprocket or the driven sprocket, used to control the synchronous rotation speed of each sample and provide real-time feedback of the rotation speed signal.

[0018] The beneficial effects of this invention are: 1. This invention employs an asymmetrical layout of "rigid drive by a sprocket at one end + elastic clamping floating support at the other end." An adjustable compression spring is installed at the floating end to continuously apply axial preload to the sample to ensure the grippers hold it firmly, while allowing the sample to freely expand and contract axially during temperature cycling from -40℃ to +150℃. In traditional equipment, both ends of the sample are rigidly fixed, and the axial thermal stress generated by thermal expansion and contraction cannot be released. This can affect the accuracy of leakage current monitoring or even cause the surge arrester valve plate to rupture. This invention, through the spring compression / rebound mechanism of the elastic clamping device, converts thermal stress into spring potential energy, ensuring that the sample only bears a preset constant axial preload throughout the entire temperature cycling cycle, completely eliminating the interference of additional thermal stress on aging assessment.

[0019] 2. This invention assigns the "torque transmission function" to the sprocket-spline spindle and the "clamping function" to the adaptive grippers with tapered surfaces, completely decoupling the two in mechanical structure. The drive spindle is connected to the fixed tapered sleeve via a spline pair (or a square tapered shank), and the rotational torque is transmitted from the side of the spline. The grippers are only responsible for radial clamping, and even if the contact state of the gripper teeth changes due to long-term wear, it does not affect the synchronization accuracy of the chain drive at all. At the same time, all driven sprockets achieve strict 1:1 synchronous transmission through the same closed-loop chain, ensuring that the rotation angle of each sample is completely consistent at any time, eliminating the uneven exposure of environmental factors caused by differences in rotational speed.

[0020] 3. The elastic conical grippers (3-6 evenly distributed around the circumference, with a conical outer wall that slides into a fixed conical sleeve) used in this invention, along with radial return spring coils at the root of the grippers, achieve push-in adaptive clamping of the sample end. The radial shrinkage ratio of a single set of grippers can reach 1:2, allowing operators to clamp or remove a sample within seconds without any tools. In contrast, existing technologies require replacing the entire set of clamps for surge arresters of different diameters, which can take tens of minutes. Furthermore, the annular serrated contact ribs (silver-plated / gold-plated) on the inner wall of the grippers can pierce the oxide layer on the electrode surface under axial preload. Combined with the parallel connection of the gripper roots via flexible conductive strips, this forms a multi-contact redundant electrical contact network. Even if individual serrated contact points fail due to long-term salt spray corrosion, the remaining contacts can still ensure the integrity of the current path.

[0021] 4. To address the issue of eccentric swaying caused by gravity during rotation of horizontally placed extra-long surge arresters (2-4 meters in length), this invention employs multiple sets of V-shaped elastic follower rollers spaced axially. The rotation axes of the two driven rollers in each set are parallel to the sample axis, arranged symmetrically in a figure-eight shape within the transverse cross-section. Utilizing the principle of gravity self-centering, the axes of samples of various diameters automatically fall on the bisector of the V-shaped angle. More importantly, the rollers passively roll using contact point friction, converting sliding friction into pure rolling friction. Simultaneously, the diamond-shaped knurling on the roller surface increases the engagement force, ensuring reliable "passive rolling" even under long-term salt spray conditions. An unexpected effect of this structure is that the contact support points continuously shift with the relative rotation of the sample and the rollers, periodically exposing small areas previously blocked from salt spray to the environment, achieving truly 360° uniform aging without dead angles.

[0022] 5. This invention addresses the sealing challenge of the rotating shaft penetrating the housing by constructing a three-tiered isolation system: "labyrinthine throttling to extend the path + annular air curtain with positive pressure blocking + externally positioned slip ring away from the corrosion source." The multi-stage sawtooth labyrinth seal extends the salt spray penetration path to its physical limit; the positive pressure air curtain (0.03~0.05MPa dry nitrogen) is continuously ejected from the micro-hole in the center of the sealing seat, forming a 360° annular air wall around the shaft, physically preventing corrosive gases from contacting the sealing interface; and the high-pressure rotating conductive slip ring is completely externally positioned at the cold end of the housing, thoroughly isolated from the high-temperature, high-humidity salt spray environment inside the housing by the aforementioned sealing structure. For the combined motion characteristics of the floating end, which involves both rotation and axial sliding, a supplementary solution of metal bellows sealing and external nitrogen purging is further adopted. This comprehensive protection system increases the continuous fault-free operating life of the conductive slip ring by several times compared to existing technologies (where the slip ring is directly exposed to salt spray). Attached Figure Description

[0023] Figure 1 This is a top view of the climate aging test apparatus for DC surge arresters according to the present invention; Figure 2 This is a perspective view of the climate aging test apparatus for DC surge arresters according to the present invention; Figure 3 This is a perspective view of the internal structure of the climate aging test device for DC surge arresters according to the present invention; Figure 4 For the present invention Figure 3 Other perspectives; Figure 5 This is a top view of the internal structure of the climate aging test device for DC surge arresters according to the present invention; Figure 6 For the present invention Figure 5 Sectional view at point BB; Figure 7For the present invention Figure 5 Sectional view at point AA; Figure 8 This is an anatomical diagram of the adaptive gripper in the climate aging test device for DC surge arresters of the present invention; Figure 9 For the present invention Figure 7 Enlarged diagram of point C in the middle.

[0024] In the picture: 1. Housing; 2. Sample; 3. Drive end assembly; 4. Drive spindle; 5. Driven sprocket; 6. Closed-loop chain; 7. Drive sprocket; 8. Adaptive gripper; 9. Floating end assembly; 10. Floating short shaft; 11. Fixed support; 12. Elastic clamping device; 13. Intermediate support assembly; 14. Fixed cone sleeve; 15. Elastic gripper; 16. Electrical contact structure; 17. Rotary conductive slip ring; 18. Adjusting nut; 19. Thrust bearing; 20. Pressure... 21. Contraction spring; 22. Radial return spring ring; 23. Raised ridge; 24. Limiting groove; 25. Limiting ring; 26. Driven roller; 27. Bearing housing; 28. Disc spring buffer seat; 29. ​​Circulating air duct module; 30. Air inlet guide structure; 31. Air return end collection structure; 32. Annular groove; 33. Sealing seat; 34. Annular convex tooth; 35. Labyrinth sealing channel; 36. Air inlet micro-hole; 37. Metal bellows; 38. Nitrogen purging interface. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] Example, refer to Figures 1-9 A climate aging test apparatus for DC surge arresters is provided, comprising a test chamber 1 with a sealed door. A sealing member is provided between the sealed door and the opening edge of the test chamber 1 to maintain a closed space isolated from the external environment during the test. The test chamber 1 houses an environmental simulation system, a sample carrying system, and an electrical loading and monitoring system. A control system is located at an appropriate position outside or inside the test chamber 1. The control system is electrically or signal-connected to the environmental simulation system, the sample carrying system, and the electrical loading and monitoring system, respectively, to coordinate the operating parameters of each system and collect status data during the test. The environmental simulation system creates an adjustable temperature, humidity, salt spray, and ultraviolet radiation environment inside the test chamber 1. The sample carrying system carries and drives the DC surge arrester sample 2 to rotate. The electrical loading and monitoring system applies a DC voltage to the sample 2 and monitors the electrical performance parameters of the sample 2 in real time.

[0027] The sample support system comprises multiple sets of rotating support positions arranged in parallel along the horizontal direction. Each set of rotating support positions corresponds to a horizontally placed DC surge arrester sample 2. The axes of all samples 2 are parallel to each other and lie in the same horizontal plane, thus forming a neat array structure of all samples 2 inside the test chamber 1, which facilitates the uniform application of the environmental medium to the surface of each sample 2. Structurally, the sample support system is divided into three parts: the drive end assembly 3, the floating end assembly 9, and the intermediate support assembly 13. These three parts are arranged sequentially along the axial direction of the sample 2, together forming a multi-point support and rotation drive system for the sample 2.

[0028] The drive assembly 3 is located on one side of the test chamber 1 and includes multiple drive spindles 4 arranged in parallel along a vertical plane. The axes of each drive spindle 4 are parallel to each other and at the same height. Each drive spindle 4 is rotatably mounted on the side wall of the test chamber 1 via a bearing assembly, with one end extending into the interior of the test chamber 1 and the other end extending out of the test chamber 1. A driven sprocket 5 is fixedly sleeved on the shaft end of each drive spindle 4 located inside the test chamber 1. All driven sprockets 5 are located in the same vertical plane and are connected to the drive sprocket 7 via the same closed-loop chain 6. The drive sprocket 7 is driven to rotate by a servo motor. When the servo motor is running, the drive sprocket 7 simultaneously drives all driven sprockets 5 to rotate at the same angular velocity through the closed-loop chain 6, thereby enabling each drive spindle 4 to achieve strictly synchronous rotation. Each drive spindle 4 is equipped with a quick-change adaptive gripper 8 at its shaft end located inside the test chamber 1. The quick-change adaptive gripper 8 rotates together with the drive spindle 4 to clamp one end of the sample 2 and transmit the rotational torque to the sample 2.

[0029] The floating end assembly 9 is located on the other side of the test chamber 1 and is opposite to the drive end assembly 3. It includes multiple floating short shafts 10, the axis of each floating short shaft 10 being coaxially aligned with the axis of the corresponding drive main shaft 4. Each floating short shaft 10 is axially slidably mounted on a fixed support 11 via a linear bearing. The fixed support 11 is fixed to the side wall or internal frame of the test chamber 1. The linear bearing constrains the radial displacement of the floating short shaft 10, allowing it to slide freely axially. At the same time, the floating short shaft 10 can rotate around its own axis as the sample 2 rotates. Each floating short shaft 10 is provided with a quick-change adaptive gripper 8 at one end near the sample 2 for holding the other end of the sample 2; each floating short shaft 10 is provided with an adjustable axial elastic clamping device 12 at the end away from the sample 2. The elastic clamping device 12 continuously applies an axial preload force toward the sample 2 to the floating short shaft 10, so that the quick-change adaptive gripper 8 at the front end of the floating short shaft 10 always presses against the end of the sample 2. When the sample 2 undergoes axial expansion and contraction due to temperature changes, the floating short shaft 10 can slide back and forth axially in the linear bearing, thereby absorbing the thermal expansion and contraction deformation of the sample 2 and avoiding additional bending stress inside the sample 2.

[0030] The intermediate support assembly 13 is disposed between the drive end assembly 3 and the floating end assembly 9, and includes multiple sets of V-shaped elastic follower rollers arranged at intervals along the axial direction of each sample 2. Each set of V-shaped elastic follower rollers is located below the sample 2, providing vertical support for the sample 2 and preventing the long-axis sample 2 from undergoing flexural deformation in the middle due to its own weight. The V-shaped elastic follower rollers are in rolling contact with the surface of the sample 2. When the sample 2 rotates around its own axis under the drive of the drive end assembly 3, the V-shaped elastic follower rollers are passively rolled along with the rotation of the sample 2, thereby providing vertical support while minimizing frictional resistance and not hindering the slight axial translation of the sample 2 caused by thermal expansion and contraction.

[0031] Reference Figure 4 and Figure 8 The quick-change adaptive gripper 8 includes a fixed conical sleeve 14 and multiple elastic grippers 15 evenly distributed along the circumference. The fixed conical sleeve 14 is a hollow conical sleeve with an inner conical surface. The outer wall of the elastic gripper 15 is a conical surface and slides in contact with the inner conical surface of the fixed conical sleeve 14. When the elastic gripper 15 is subjected to an axial thrust, its outer conical surface slides along the inner conical surface of the fixed conical sleeve 14, causing the elastic gripper 15 to undergo radial contraction deformation. The inner wall of the elastic gripper 15 is provided with an electrical contact structure 16. When the elastic gripper 15 contracts radially, the electrical contact structure 16 on its inner wall tightly fits against the outer surface of the end of the sample 2, realizing the dual functions of mechanical clamping and electrical conduction. The elastic gripper 15 relies on axial thrust to contract radially to clamp or release the end of the sample 2. When the axial thrust increases, the clamping force increases; when the axial thrust decreases, the clamping force decreases, thereby achieving adaptive clamping of the end of the sample 2.

[0032] Reference Figure 7 The electrical loading and monitoring system includes a rotating conductive slip ring 17 located on the outside of the test chamber 1 and connected to each drive main shaft 4 or floating short shaft 10. The stator end of the rotating conductive slip ring 17 is fixed to the outside of the test chamber 1, and the rotor end rotates together with the drive main shaft 4 or floating short shaft 10. Through sliding contact, the electrical signal or loading voltage in the rotating state is led out from the rotating component to the stationary control system, thereby realizing uninterrupted electrical loading and monitoring of the rotating sample 2. A dynamic sealing structure is provided between the drive end assembly 3 and the floating end assembly 9 and the chamber wall of the test chamber 1. The dynamic sealing structure is used to maintain the airtightness of the test chamber 1 at the position where the rotating shaft or sliding shaft penetrates the chamber wall, preventing corrosive media such as salt spray and humid heat gas inside the chamber from leaking to the external environment, and at the same time preventing impurities in the external environment from entering the interior of the test chamber 1.

[0033] Reference Figure 4 and Figure 7The axial elastic clamping device 12 includes an adjusting nut 18, a thrust bearing 19, and a compression spring 20. The adjusting nut 18 is located at the end of the floating short shaft 10 extending from the fixed support 11, and is threadedly connected to the end of the floating short shaft 10. Rotating the adjusting nut 18 changes its axial position on the floating short shaft 10. The thrust bearing 19 is located between the adjusting nut 18 and the fixed support 11, with one side contacting the end face of the adjusting nut 18 and the other side contacting the end of the compression spring 20. The thrust bearing 19 isolates the relative rotation between the adjusting nut 18 and the compression spring 20 when the floating short shaft 10 rotates, preventing the compression spring 20 from generating additional torque due to shaft torsion. The compression spring 20 is fitted onto the floating short shaft 10 and located between the fixed support 11 and the thrust bearing 19. One end of the compression spring 20 abuts against the end face of the fixed support 11, and the other end abuts against the adjusting nut 18 via the thrust bearing 19. The compression of the compression spring 20 is changed by rotating the adjusting nut 18, thereby adjusting the magnitude of the axial preload applied to the sample 2. When the adjusting nut 18 is rotated toward the fixed support 11, the compression spring 20 is further compressed, its elastic force increases, and the axial preload applied to the floating short shaft 10 and finally transmitted to the sample 2 increases accordingly. Conversely, when the adjusting nut 18 is rotated away from the fixed support 11, the compression of the compression spring 20 decreases, and the axial preload decreases accordingly.

[0034] Reference Figures 7-8 The fixed cone sleeve 14 of the quick-change adaptive gripper 8 is detachably connected to the shaft end of the drive spindle 4 via a spline pair or a square cone shank. The spline pair or square cone shank can reliably transmit rotational torque, while allowing the fixed cone sleeve 14 to be quickly disassembled and installed when replacement or maintenance is required. A radial return spring coil 21 is provided at the root of the elastic gripper 15. The radial return spring coil 21 clamps the root of each elastic gripper 15 in the circumferential direction, so that each elastic gripper 15 is in an open state when not under axial pressure. At this time, a gap is left between the inner wall of the elastic gripper 15 and the end of the sample 2, which facilitates the smooth insertion or removal of the end of the sample 2, realizing quick replacement. The electrical contact structure 16 is an annular sawtooth contact rib extending in the circumferential direction of the inner wall of the elastic gripper 15. The surface of the contact rib is provided with a silver plating layer or a gold plating layer. The silver plating layer or gold plating layer has excellent conductivity and oxidation resistance, and can maintain low contact resistance in a long-term salt spray corrosion environment. The roots of each elastic gripper 15 are connected in parallel by a flexible conductive strip. The flexible conductive strip connects the electrical contact structures 16 of each elastic gripper 15 into a whole, ensuring that even if individual gripper pieces have poor contact, the overall electrical conduction can still be maintained through other gripper pieces and the flexible conductive strip, thereby improving the reliability of the electrical connection.

[0035] The outer wall of the elastic gripper 15 is provided with a protruding rib 22 for limiting sliding. The protruding rib 22 extends along the generatrix direction of the elastic gripper 15. The inner conical surface of the fixed cone sleeve 14 is provided with a limiting groove 23 that mates with the protruding rib 22. The protruding rib 22 is embedded in the limiting groove 23 and can slide along the limiting groove 23. This mating structure restricts the circumferential rotation of the elastic gripper 15 relative to the fixed cone sleeve 14, so that the elastic gripper 15 and the fixed cone sleeve 14 can only slide relative to each other axially and cannot rotate relative to each other circumferentially, thereby ensuring the stability of torque transmission. A limiting ring 24 is provided at the opening of the inner conical surface of the fixed cone sleeve 14 to prevent the elastic gripper 15 from falling out. The limiting ring 24 is fixed at the large-diameter end opening of the fixed cone sleeve 14. When the elastic gripper 15 opens outward and moves in the opening direction under the action of the radial return spring coil 21, the limiting ring 24 blocks the root of the elastic gripper 15 and prevents the elastic gripper 15 from falling out of the fixed cone sleeve 14.

[0036] Reference Figure 6 The V-shaped elastic follower roller includes two longitudinally horizontally arranged driven rollers 25. The rotation axes of the two driven rollers 25 are parallel to the axis of the sample 2. The two driven rollers 25 are arranged symmetrically in a figure-eight shape in the transverse cross section, that is, the axes of the two driven rollers 25 are symmetrically distributed at a certain angle on the horizontal plane. The outer walls of the two driven rollers 25 together form a V-shaped support groove. The sample 2 is placed in the V-shaped support groove, and the outer walls of the two driven rollers 25 support the sample 2 from both sides below. The V-shaped structure automatically centers the sample 2 laterally, preventing the sample 2 from shifting laterally during rotation. The surface of each driven roller 25 is provided with a diamond-shaped knurled or herringbone-shaped knurled structure. The knurled structure increases the coefficient of friction between the surface of the driven roller 25 and the outer surface of the sample 2, enabling the driven roller 25 to passively roll more reliably with the rotation of the sample 2 and reducing slippage. Each driven roller 25 is mounted on a bearing housing 26 at both ends via rolling bearings. A disc spring buffer seat 27 is provided at the bottom of the bearing housing 26. The disc spring buffer seat 27 is composed of stacked disc springs, which gives the driven roller 25 a vertical floating stroke. When the sample 2 causes a small vertical jump due to rotational eccentricity or thermal deformation, the disc spring buffer seat 27 absorbs the jump through elastic deformation, thus avoiding rigid impact between the sample 2 and the roller.

[0037] The environmental simulation system includes a temperature and humidity control module, a salt spray generation module, an ultraviolet irradiation module, and a circulating air duct module 28. The temperature and humidity control module regulates the temperature and humidity inside the test chamber 1. The salt spray generation module generates salt spray and delivers it into the test chamber 1. The ultraviolet irradiation module emits ultraviolet light onto the surface of the sample 2 to simulate the ultraviolet aging effect in sunlight. The circulating air duct module 28 drives the air circulation within the chamber, ensuring a uniform distribution of the temperature, humidity, and salt spray concentration fields within the chamber. The salt spray generation module sprays salt spray in a horizontal direction, perpendicular to the axis of each sample 2, allowing the salt spray airflow to sweep horizontally across the surface of each sample 2, ensuring that salt spray particles settle uniformly across the entire circumferential surface of the sample 2. The test chamber 1 has an air inlet guide structure 29 and a return air collection structure 30 on its two opposite side walls. The air inlet guide structure 29 is connected to the salt spray generating module. The salt spray airflow enters the test chamber 1 after being rectified by the air inlet guide structure 29. The return air collection structure 30 is connected to the return air inlet of the circulating fan. The airflow inside the chamber is collected by the return air collection structure 30 and returned to the circulating fan, forming a closed loop circulation.

[0038] Reference Figure 3 The air inlet guide structure 29 includes multiple vertically arranged rotatable arc-shaped guide vanes. The arc-shaped surface of each arc-shaped guide vane faces the air inlet direction. Each arc-shaped guide vane is connected by a linkage mechanism and its angle can be adjusted synchronously. By changing the deflection angle of the arc-shaped guide vane, the distribution ratio of the salt spray airflow in the vertical direction can be adjusted, and the salt spray airflow can be evenly distributed in the vertical direction to the height range of each sample 2, so that samples 2 at different heights can receive an equal amount of salt spray airflow. The return air collection structure 30 includes a gradually expanding collection hood and a porous flow equalization damping plate disposed on the air inlet side of the gradually expanding collection hood. The flow cross-section of the gradually expanding collection hood gradually expands along the airflow direction, causing the airflow to decelerate and pressurize within the collection hood. The opening ratio of the porous flow equalization damping plate increases from the center to the edge. This variable opening ratio design makes the resistance of the airflow passing through the damping plate radially distributed to match the velocity distribution within the collection hood, thereby ensuring that the return airflow is evenly distributed on the cross-section of the collection hood and avoiding uneven flow field within the box caused by local eddies.

[0039] Reference Figure 7 and Figure 9The dynamic sealing structure of the drive end assembly 3 includes a multi-stage sawtooth annular groove 31 disposed on the outer wall of the drive spindle 4, and a sealing seat 32 fixedly disposed on the housing wall. The sealing seat 32 is sleeved on the outside of the drive spindle 4 or the floating short shaft 10 and fixed in the mounting hole of the housing wall. The inner wall of the sealing seat 32 is provided with annular protrusions 33 that interlock with the annular groove 31. The annular protrusions 33 extend into the annular groove 31 but do not contact the bottom of the groove. The sealing seat 32 and the drive spindle 4 or the floating short shaft 10 form a labyrinth sealing channel 34. When the airflow passes through the labyrinth sealing channel 34, it undergoes multiple throttling and expansion, and the resistance increases significantly, thereby effectively preventing the leakage of corrosive gases inside the housing. At least one air inlet micro-hole 35 is evenly distributed along the circumference at the middle position of the sealing seat 32. Each air inlet micro-hole 35 is connected to an external positive pressure inert gas source. The positive pressure inert gas is injected into the labyrinth sealing channel 34 through the air inlet micro-hole 35, forming an annular positive pressure air curtain in the labyrinth sealing channel 34. The pressure of this positive pressure air curtain is higher than the air pressure inside the test chamber 1, thereby forming an air pressure gradient from the sealing position to the inside of the chamber, further preventing the salt spray gas inside the chamber from penetrating to the outside. At the same time, the inert gas itself does not react chemically with the medium inside the chamber and does not affect the test environment.

[0040] The dynamic sealing structure of the floating end assembly 9 is a metal bellows 36 sealing assembly. The metal bellows 36 is a telescopic tubular component made of thin-walled metal. One end is welded to the outer wall of the floating short shaft 10, and the other end is welded to the fixed support 11 or the box wall. The metal bellows 36 expands and contracts with the axial sliding of the floating short shaft 10. At the same time, the wall of the metal bellows 36 itself does not rotate relative to the floating short shaft 10, but adapts to the rotation of the floating short shaft 10 through its flexible deformation, thereby maintaining an absolute seal under the combined motion state of the floating short shaft 10 rotating and sliding axially. A nitrogen purging port 37 is provided on the outside of the metal bellows 36. Nitrogen is continuously blown onto the outer surface of the metal bellows 36 through the purging port, forming a positive pressure nitrogen protective layer on the outside of the bellows. This prevents the salt spray condensate leaking from inside the box from accumulating on the surface of the bellows and causing corrosion, thus extending the service life of the bellows.

[0041] The control system includes a PLC controller and a touch screen operation panel. The PLC controller, as the control core, receives feedback signals from various sensors and outputs control commands according to preset programs. The touch screen operation panel is used by operators to set test parameters, view real-time data, and manually intervene in equipment operation. The test chamber 1 is equipped with temperature sensors, humidity sensors, salt spray concentration sensors, and ultraviolet radiation intensity sensors, which are used to monitor the temperature, humidity, salt spray concentration, and ultraviolet radiation intensity inside the chamber in real time and transmit the monitoring data to the PLC controller. Each drive spindle 4 or floating short shaft 10 is equipped with a leakage current sensor corresponding to each sample 2, used to collect the leakage current value of each sample 2 under DC voltage in real time. The signal lines of each leakage current sensor are led out to the control system via a rotating conductive slip ring 17, which ensures continuous conduction of the signal lines during rotation. The control system also includes a frequency converter connected to the servo motor and a rotary encoder connected to the drive sprocket 7 or the driven sprocket 5. The frequency converter adjusts the speed and torque of the servo motor according to the instructions of the PLC controller. The rotary encoder detects the rotation angle and speed of the sprocket in real time and feeds it back to the PLC controller to form a closed-loop speed control, which is used to control the synchronous rotation speed of each sample 2 and feed back the speed signal in real time.

[0042] The technical principle of this invention is as follows: a mechanical decoupling architecture with one end rigid chain drive and the other end elastic floating clamping is adopted, so that the multi-station synchronous rotation drive and the thermal expansion and contraction displacement compensation function of the sample 2 are independently undertaken by the drive end component 3 and the floating end component 9 respectively. The drive end assembly 3 transmits the rotational motion of the servo motor to all drive spindles 4 simultaneously through the same closed-loop chain 6, achieving a strict 1:1 synchronous uniform rotation of each sample 2, ensuring that each sample 2 undergoes uniform aging tests under the same environmental conditions. The floating end assembly 9 allows the floating short shaft 10 to slide freely along the axial direction through a linear bearing, and the axial elastic clamping device 12 continuously applies axial preload. This preload pushes the end of the sample 2 to press against the quick-change adaptive gripper 8 of the drive end, causing the elastic gripper 15 of the gripper to slide along the inner conical surface of the fixed conical sleeve 14 and radially contract, achieving automatic centering and clamping of the end of the sample 2 and electrical conduction. On the other hand, when the sample 2 undergoes axial expansion and contraction due to temperature cycling, the floating short shaft 10 compresses or releases the compression spring 20 under the push of the sample 2, converting thermal deformation into the elastic deformation of the spring, thereby completely releasing the additional axial stress and bending stress generated inside the sample 2 due to thermal expansion and contraction. The quick-change adaptive gripper 8 converts the axial preload into radial clamping force through the conical engagement of the fixed conical sleeve 14 and the elastic gripper 15. Combined with the silver- or gold-plated annular serrated contact ribs on the inner wall, it achieves low-resistance electrical connection. Each elastic gripper 15 is connected in parallel via a flexible conductive strip to further ensure conductivity reliability. The V-shaped elastic follower roller of the intermediate support assembly 13 provides vertical support for the long-axis sample 2 through rolling contact and automatically aligns laterally. The disc spring buffer seat 27 absorbs rotational vibration. The environmental simulation system uses horizontal salt spray injection, combined with arc-shaped guide vanes at the air inlet and a multi-porous flow-equalizing damping plate with variable opening ratio at the air return end, to ensure that the salt spray airflow evenly covers the surface of all samples 2. The drive end adopts a combined sealing structure of labyrinth seal and positive pressure air curtain, while the floating end uses a retractable metal bellows 36 for sealing and nitrogen purging, respectively adapting to the sealing requirements of two different motion forms: pure rotation and rotation plus axial sliding. The control system forms a closed loop of rotation speed through PLC, frequency converter and rotary encoder. It realizes real-time monitoring of environmental parameters and electrical performance of sample 2 through various sensors and leakage current sensor. The whole system constitutes a climate aging test system with synchronous and uniform rotation, free release of thermal stress, reliable electrical contact, uniform environmental field, tight sealing and controllable operation.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A climate aging test apparatus for DC surge arresters, comprising a test chamber (1) with a sealed door, an environmental simulation system, a sample carrying system, an electrical loading and monitoring system, and a control system connected to each system, characterized in that: The sample carrying system includes multiple sets of rotating support positions arranged side by side along the horizontal direction, each set of rotating support positions corresponding to a horizontally placed DC surge arrester sample (2). The sample carrying system includes: The drive end assembly (3) is located on one side of the test chamber (1) and includes multiple drive spindles (4) arranged in parallel along a vertical plane. Each drive spindle (4) has a driven sprocket (5) fixedly sleeved on the shaft end located inside the test chamber (1). All driven sprockets (5) are meshed with the drive sprocket (7) through the same closed-loop chain (6). The drive sprocket (7) is driven to rotate by a servo motor. Each drive spindle (4) has a quick-change adaptive gripper (8) on the shaft end located inside the test chamber (1). The floating end assembly (9) is located on the other side of the test chamber (1) and is opposite to the drive end assembly (3). It includes multiple floating short shafts (10). Each floating short shaft (10) is axially slidably mounted on the fixed support (11) via a linear bearing. Each floating short shaft (10) is provided with the quick-change adaptive gripper (8) at the end near the specimen (2) and with an adjustable axial elastic clamping device (12) at the end away from the specimen (2). The elastic clamping device (12) continuously applies an axial preload towards the specimen (2) to the floating short shaft (10). The intermediate support assembly (13) is located between the drive end assembly (3) and the floating end assembly (9), and includes multiple sets of V-shaped elastic follower rollers arranged at intervals along the axial direction of each sample (2). Each set of V-shaped elastic follower rollers provides vertical support to the sample (2) and rolls passively as the sample (2) rotates. The quick-change adaptive gripper (8) includes a fixed cone sleeve (14) and multiple elastic grippers (15) evenly distributed along the circumference. The outer wall of the elastic gripper (15) is a cone surface and slides in cooperation with the inner cone surface of the fixed cone sleeve (14). The inner wall of the elastic gripper (15) is provided with an electrical contact structure (16). The elastic gripper (15) relies on axial thrust to radially contract to hold or release the end of the sample (2). The electrical loading and monitoring system includes a rotating conductive slip ring (17) located on the outside of the test chamber (1) and connected to each of the drive main shafts (4) or floating short shafts (10). A dynamic sealing structure is provided between the drive end assembly (3) and the floating end assembly (9) and the wall of the test chamber (1).

2. The climate aging test apparatus for DC surge arresters according to claim 1, characterized in that: The axial elastic clamping device (12) includes: An adjusting nut (18) is provided at the end of the floating short shaft (10) that extends out of the fixed support (11); A thrust bearing (19) is disposed between the adjusting nut (18) and the fixed support (11); A compression spring (20) is fitted on the floating short shaft (10) and located between the fixed support (11) and the thrust bearing (19). One end of the compression spring (20) abuts against the end face of the fixed support (11), and the other end abuts against the adjusting nut (18) through the thrust bearing (19). The amount of compression of the compression spring (20) is changed by rotating the adjusting nut (18) to adjust the magnitude of the axial preload applied to the specimen (2).

3. The climate aging test apparatus for DC surge arresters according to claim 1, characterized in that: The fixed cone sleeve (14) of the quick-change adaptive gripper (8) is detachably connected to the shaft end of the drive spindle (4) via a spline pair or a square cone shank; a radial return spring ring (21) is provided at the root of the elastic gripper (15) so that each elastic gripper (15) is in an open state when not subjected to axial pressure; the electrical contact structure (16) is an annular sawtooth contact rib extending along the circumferential direction of the inner wall of the elastic gripper (15), and the surface of the contact rib is provided with a silver plating layer or a gold plating layer; the roots of each elastic gripper (15) are connected in parallel via a flexible conductive strip.

4. The climate aging test apparatus for DC surge arresters according to claim 1, characterized in that: The outer wall of the elastic gripper (15) is provided with a protrusion (22) for limiting sliding, and the inner conical surface of the fixed conical sleeve (14) is provided with a limiting groove (23) that cooperates with the protrusion (22). The opening of the inner conical surface of the fixed conical sleeve (14) is provided with a limiting ring (24) to prevent the elastic gripper (15) from falling out.

5. The climate aging test apparatus for DC surge arresters according to claim 1, characterized in that: The V-shaped elastic follower roller includes two longitudinally horizontally arranged driven rollers (25). The rotation axes of the two driven rollers (25) are parallel to the axis of the sample (2). The two driven rollers (25) are arranged in a figure-eight symmetrical inclined shape in the transverse section. The outer walls of the two driven rollers (25) together form a V-shaped support groove. The surface of each driven roller (25) is provided with a diamond knurling or herringbone knurling structure. The two ends of each driven roller (25) are mounted on a bearing seat (26) through rolling bearings. A disc spring buffer seat (27) is provided at the bottom of the bearing seat (26) so that the driven roller (25) has a vertical floating stroke.

6. The climate aging test apparatus for DC surge arresters according to claim 1, characterized in that: The environmental simulation system includes a temperature and humidity control module, a salt spray generation module, an ultraviolet irradiation module, and a circulating air duct module (28). The salt spray generation module sprays salt spray in a horizontal direction and perpendicular to the axis of each sample (2). The test chamber (1) has an air inlet guide structure (29) and a return air collection structure (30) on its opposite side walls. The air inlet guide structure (29) is connected to the salt spray generation module, and the return air collection structure (30) is connected to the return air inlet of the circulating fan.

7. The climate aging test apparatus for DC surge arresters according to claim 6, characterized in that: The air inlet guide structure (29) includes multiple vertically arranged rotatable arc-shaped guide blades. Each arc-shaped guide blade is connected by a linkage mechanism and its angle can be adjusted synchronously to distribute the salt spray airflow evenly along the vertical direction to the height range of each sample (2). The return air collection structure (30) includes a gradually expanding collection hood and a porous flow equalization damping plate disposed on the air inlet side of the gradually expanding collection hood. The opening ratio of the porous flow equalization damping plate increases from the center to the edge.

8. The climate aging test apparatus for DC surge arresters according to claim 1, characterized in that: The dynamic sealing structure of the drive end assembly (3) includes a multi-stage sawtooth annular groove (31) disposed on the outer wall of the drive spindle (4) and a sealing seat (32) fixedly disposed on the box wall. The inner wall of the sealing seat (32) is provided with annular protrusions (33) that interlock with the annular groove (31). The sealing seat (32) and the drive spindle (4) or the floating short shaft (10) form a labyrinth sealing channel (34). At least one air inlet microhole (35) is evenly distributed in the circumferential direction at the middle position of the sealing seat (32). Each air inlet microhole (35) is connected to an external positive pressure inert gas source to form an annular positive pressure air curtain in the labyrinth sealing channel (34).

9. The climate aging test apparatus for DC surge arresters according to claim 8, characterized in that: The dynamic sealing structure of the floating end assembly (9) is a metal bellows (36) sealing assembly. One end of the metal bellows (36) is welded to the outer wall of the floating short shaft (10), and the other end is welded to the fixed support (11) or the box wall. The metal bellows (36) extends and retracts as the floating short shaft (10) slides axially. A nitrogen purging port (37) is provided on the outside of the metal bellows (36).

10. The climate aging test apparatus for DC surge arresters according to any one of claims 1-9, characterized in that: The control system includes a PLC controller and a touch screen operation panel. The test chamber (1) is equipped with a temperature sensor, a humidity sensor, a salt spray concentration sensor, and an ultraviolet radiation intensity sensor. Each of the drive spindles (4) or floating short shafts (10) is equipped with a leakage current sensor corresponding to each sample (2). The signal lines of each leakage current sensor are led out to the control system through the rotating conductive slip ring (17). The control system also includes a frequency converter connected to the servo motor and a rotary encoder connected to the drive sprocket (7) or the driven sprocket (5) to control the synchronous rotation speed of each sample (2) and provide real-time feedback of the rotation speed signal.

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