Fatigue life determination device for refractory metal elastic element

Abstract

Disclosed in the present invention is a fatigue life determination device for a refractory metal elastic element. A movable rod is slidably and sealingly inserted on a pressure bearing cavity; a driving mechanism for driving the movable rod to move reciprocatingly is connected to the movable rod; one end of a fixed rod extends into the pressure bearing cavity, a refractory metal elastic element is abutted between said end and the movable rod, and the other end of the fixed rod extends out of the pressure bearing cavity and a heating furnace and is connected to a vibration frequency detection sensor; a pressurizing channel for high pressure gas to flow is formed in the fixed rod; a pressurizing opening communicated with the pressurizing channel is formed in the end wall of the fixed rod corresponding to the interior of the refractory metal elastic element; an internal pressure connector communicated with the pressurizing channel is formed in the position of the fixed rod located outside the heating furnace; an external pressure connector communicated with the interior of the pressure bearing cavity is formed in a side wall of the pressure bearing cavity; the external pressure connector is communicated with an external pressure pipeline extending out of the heating furnace; and the external pressure pipeline and the internal pressure connector are both communicated with a high-pressure charging mechanism. Thus, the loss rate of temperature and pressure is reduced, and the use requirements of special working conditions are met.

Description

A device for measuring fatigue life of refractory metal elastic elements Technical Field

[0001] The present invention relates to the technical field of refractory metal elastic element measuring equipment, in particular to a refractory metal elastic element fatigue life measuring device. Background Art

[0002] Metal bellows, as a commonly used elastic element and important basic component in mechanical equipment, utilizes the elastic deformation of thin-walled metal materials to achieve flexible connection, displacement compensation, and mechanical sealing. This is achieved by utilizing the characteristic of thin-walled corrugated metal tubing, which changes shape and size under external loads and returns to its original state when the load is removed. Fatigue life is one of the important indicators that characterize the performance of metal bellows. Dedicated testing equipment is required to determine the durability of metal bellows under alternating loads. This is also the most direct and effective way to analyze fatigue failure modes. With the continuous expansion of the application field of metal bellows, bellows made of refractory alloys such as tantalum and niobium alloys that can withstand ultra-high temperatures exceeding 1000°C and external pressures of 15MPa have been applied to special equipment. Designing and manufacturing fatigue performance testing equipment for ultra-high temperature and high pressure bellows has become one of the key issues that need to be addressed.

[0003] Among the currently available literature and patents, there is no device that can withstand such ultra-high temperatures and simultaneously test the fatigue life of metal bellows under internal and external pressure conditions. The main difficulties are concentrated in the following aspects:

[0004] (1) The measurement accuracy is relatively low. Traditional high-temperature and high-pressure life detection devices lack the ability to detect the status of the bellows. They cannot immediately detect the number of times the bellows have experienced fatigue failure, and thus cannot accurately quantify the life index. Under high-temperature and high-pressure operating conditions, the failure of the bellows is closely related to factors such as local instability and crack initiation and expansion. Therefore, improving the monitoring capability of the device is a key factor in achieving high-precision life measurement.

[0005] (2) It is difficult to maintain heat and pressure in ultra-high temperature and high pressure environments. The design of the entire device should use as little insulation cotton as possible and improve the sealing effect as much as possible to reduce the loss rate of temperature and pressure and meet the requirements of special working conditions.

[0006] (3) High manufacturing cost. Refractory alloy materials are expensive. Using refractory alloy materials that can withstand temperatures above 1000°C for all components of the entire test device is not conducive to cost control. Therefore, corresponding auxiliary measures should be taken during the design and manufacturing process.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to provide a fatigue life measurement device for refractory metal elastic elements to solve the problems existing in the above-mentioned prior art, to fully reduce the loss rate of temperature and pressure, to meet the requirements of use in special working conditions, and to accurately obtain test data on factors such as failure and local instability of refractory metal elastic elements, crack initiation and expansion, etc. under high temperature and high pressure operating conditions.

[0009] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention provides a fatigue life measuring device for a refractory metal elastic element, comprising a pressure-bearing cavity and a heating furnace surrounding the outer peripheral side of the pressure-bearing cavity, a movable rod being slidably and sealedly inserted into the pressure-bearing cavity, one end of the movable rod extending out of the heating furnace and connected to a driving mechanism for driving the movable rod to move back and forth, and the other end extending into the interior of the pressure-bearing cavity, a fixed rod being inserted into the inner wall of the pressure-bearing cavity opposite to the movable rod, the fixed rod being coaxially arranged with the movable rod, one end of the fixed rod extending into the interior of the pressure-bearing cavity, and a refractory metal elastic element abutting against the movable rod, and the other end extending out of the pressure-bearing cavity and the heating furnace and connected to a vibration frequency detection sensor;

[0010] A charging channel for high-pressure gas flow is provided in the fixing rod, a charging port connected to the charging channel is provided on the end wall of the fixing rod corresponding to the inside of the refractory metal elastic element, an internal pressure interface connected to the charging channel is provided on the position of the fixing rod located outside the heating furnace, an external pressure interface connected to the interior of the pressure-bearing cavity is provided on the side wall of the pressure-bearing cavity, the external pressure interface is connected to an external pressure pipeline extending out of the heating furnace, and both the external pressure pipeline and the internal pressure interface are connected to a high-pressure inflation mechanism.

[0011] Preferably, one end of the movable rod extends into the pressure-bearing cavity and is provided with a first pressure plate, and the end of the fixed rod extending into the pressure-bearing cavity is provided with a second pressure plate, the refractory metal elastic element is abutted against the second pressure plate and the first pressure plate, and a channel connecting the charging port and the interior of the refractory metal elastic element is opened on the second pressure plate.

[0012] Preferably, the portion of the fixing rod extending out of the outside of the heating furnace is sleeved with a pad, and the vibration frequency detection sensor is attached to all four sides of the pad.

[0013] Preferably, the pad is a ceramic pressing block, which is provided with a through hole for the fixing rod to pass through. Both sides of the ceramic pressing block along the axis of the fixing rod are abutted against limiting nuts, and the limiting nuts are threadedly connected to the fixing rod.

[0014] Preferably, the end of the fixing rod extending out of the ceramic pressing block and the limiting nut is threadedly connected to a heat dissipation rod, and a heat dissipation blind hole is provided at one end of the heat dissipation rod away from the ceramic pressing block, and a plurality of heat dissipation holes connected to the heat dissipation blind hole are provided on the outer peripheral wall of the heat dissipation rod.

[0015] Preferably, a first metal bellows is sealed between the inner wall of the pressure-bearing cavity for the movable rod to be inserted and the first pressure plate, and the first metal bellows is sleeved on the outer peripheral side of the movable rod.

[0016] Preferably, a clamp is fixed on the outer wall of the pressure-bearing cavity, and the clamp is sleeved on the movable rod and is slidably connected to the movable rod.

[0017] Preferably, a second metal bellows is connected between the external pressure interface and the external pressure pipeline.

[0018] Preferably, the internal pressure interface is connected to an internal pressure pipeline, the internal pressure pipeline and the external pressure pipeline are connected in parallel at the air outlet of the high-pressure inflation mechanism, and the internal pressure pipeline and the external pressure pipeline are both provided with heat exchangers for dissipating heat therefrom.

[0019] Preferably, the vibration frequency detection sensor is electrically connected to an oscilloscope that enhances signal characteristic values.

[0020] Preferably, two groups of synchronously extending resistance wires are arranged around the furnace chamber of the heating furnace, one of the resistance wires is electrically connected to a normally open power supply, and the other resistance wire is electrically connected to a backup power supply, and both the normally open power supply and the backup power supply are equipped with temperature switches that respectively control the on and off of the two resistance wires.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] First, a movable rod is provided, one end of the movable rod is connected to the driving mechanism, and a refractory metal elastic element is provided between the other end and the fixed rod, so that the movable rod moves back and forth under the driving action of the driving mechanism and squeezes the refractory metal elastic element, and a vibration frequency detection sensor is provided on the fixed rod to monitor the refractory metal elastic element. Furthermore, a heating furnace is used to conduct heat to the pressure cavity so that the required high-temperature environment is formed inside the pressure cavity. The high-pressure inflation mechanism is connected through the external pressure pipe and the internal pressure interface, and the high pressure surrounding the periphery of the refractory metal elastic element is input into the pressure cavity through the external pressure pipe. The pressure is then compressed through the internal pressure interface and the pressure charging channel. The interior of the refractory metal elastic element is pressurized through the pressure port to ensure that a high-pressure environment is maintained inside and outside the refractory metal elastic element, and to avoid errors in the test results caused by unbalanced pressure inside and outside the refractory metal elastic element. The fixed rod is plugged and fixed to the pressure cavity, and the movable rod is seal-plugged to the pressure cavity to avoid high pressure leakage at the positions between the side wall of the pressure cavity and the fixed rod and the movable rod respectively, so as to fully reduce the loss rate of temperature and pressure, meet the use requirements of special working conditions, and be able to accurately obtain test data on failure, damage, local instability, crack initiation and expansion of refractory metal elastic elements under high temperature and high pressure operating conditions.

[0023] Second, one end of the movable rod extends into the pressure-bearing cavity and is provided with a first pressure plate, and the end of the fixed rod extending into the pressure-bearing cavity is provided with a second pressure plate, and a refractory metal elastic element is abutted between the second pressure plate and the first pressure plate, and a channel connecting the charging port and the interior of the refractory metal elastic element is opened on the second pressure plate. By arranging the first pressure plate and the second pressure plate to increase the contact surface of the movable rod and the fixed rod with the refractory metal elastic element respectively, the refractory metal elastic elements of corresponding structures can be matched without excessively enlarging the cross-section of the movable rod or the fixed rod, thereby avoiding the movable rod or the fixed rod having a large cross-section, resulting in reduced sealing of the connection between the movable rod or the fixed rod and the pressure-bearing cavity.

[0024] Third, the part of the fixed rod extending out of the outside of the heating furnace is sleeved with a pad, and vibration frequency detection sensors are attached on all sides of the pad. The pad is set to transmit the vibration frequency of the refractory metal elastic element and the fixed rod. Vibration frequency detection sensors are attached on all sides of the pad to detect the vibration frequencies at different points and in different directions. When the refractory metal elastic element becomes locally unstable or fails as a whole, the signal fed back by the vibration frequency detection sensor exceeds the threshold set under the normal state of the system and an alarm is issued. The corresponding number of counts at this time is the fatigue life of the refractory metal elastic element under high temperature and high pressure conditions, and this method can accurately determine the number of times the test piece undergoes local deformation and overall failure.

[0025] Fourth, the gasket is a ceramic pressure block, which is provided with a through hole for the fixing rod to pass through. The ceramic pressure block is abutted against limiting nuts on both sides along the axis of the fixing rod. The limiting nuts are threadedly connected to the fixing rod. The ceramic pressure block is provided to ensure its high temperature resistance and heat insulation properties, thereby preventing the vibration frequency detection sensor from being damaged by high temperature, and the abutment of the two limiting nuts is used to ensure the firmness of the connection between the ceramic pressure block and the fixing rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] FIG1 is a schematic diagram of the overall structure of the present invention;

[0028] FIG2 is a schematic diagram of the cooperation between the heating furnace and the pressure-bearing cavity of the present invention;

[0029] Among them, 1- high-pressure inflation mechanism, 2- main valve, 3- distributor, 4- pressure gauge, 5- first distributing valve, 6- second distributing valve, 7- external pressure pipeline, 8- internal pressure pipeline, 9- heat exchanger, 10- cylinder, 11- movable rod, 12- first metal bellows, 13- clamp, 14- heating furnace, 15- straight pipe section, 16- second metal bellows, 17- first pressure plate, 18- refractory metal elastic element, 19- fixing rod, 20- pad, 21- oscilloscope, 22- pressure cavity, 23- second pressure plate, 24- charging channel, 25- temperature controller, 26- top cover, 27- bottom cover, 28- normally open power supply, 29- backup power supply, 30- temperature switch. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The purpose of the present invention is to provide a fatigue life measurement device for refractory metal elastic elements to solve the problems existing in the above-mentioned prior art, to fully reduce the loss rate of temperature and pressure, to meet the requirements of use in special working conditions, and to accurately obtain test data on factors such as failure and local instability of refractory metal elastic elements, crack initiation and expansion, etc. under high temperature and high pressure operating conditions.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] As shown in Figures 1 to 2, this embodiment provides a fatigue life measuring device for a refractory metal elastic element, comprising a pressure-bearing cavity 22 and a heating furnace 14 surrounding the outer periphery of the pressure-bearing cavity 22, wherein the maximum experimental temperature that the heating furnace 14 can reach is 1300°C. Preferably, a temperature sensor is provided in the pressure-bearing cavity 22, and the temperature sensor is electrically connected to a temperature controller 25 located outside the heating furnace 14 to adjust the heating temperature of the heating furnace 14 according to the monitoring result of the temperature sensor. The pressure-bearing cavity 22 is made of a high-temperature resistant refractory alloy material. In terms of strength, it should be ensured that no damage occurs during the experiment according to the results of finite element analysis. Specifically, the pressure-bearing cavity 22 is a welded part. Based on cost considerations, the size of the pressure-bearing cavity 22 should be reduced as much as possible, that is, it can meet the pressure requirements and accommodate the refractory metal elastic element 18. A movable rod 11 is slidably and sealedly inserted into the pressure-bearing cavity 22. One end of the movable rod 11 extends out of the heating furnace 14 and is connected to a driving mechanism that drives the movable rod 11 to move back and forth, and the other end extends into the pressure-bearing cavity 22. Inside the cavity 22, preferably, the driving mechanism adopts a cylinder 10 and is equipped with a two-position two-way valve and a frequency converter. The cylinder 10, the two-position two-way valve, and the frequency converter form an operation control system so that the movement stroke and movement frequency of the movable rod 11 can be adjusted, which makes the present invention applicable to the determination of fatigue life under various displacements and movement rates, and the movable rod 11 is equipped with a proximity switch, and the movements of the movable rod 11 are counted by the proximity switch; a fixed rod 19 is inserted into the inner wall of the pressure-bearing cavity 22 opposite to the movable rod 11, and the fixed rod 19 is coaxially arranged with the movable rod 11. One end of the fixed rod 19 extends into the interior of the pressure-bearing cavity 22, and a refractory metal elastic element 18 is abutted against the movable rod 11, and the other end extends out of the pressure-bearing cavity 22 and the heating furnace 14, and is connected to a vibration frequency detection sensor; and in order to reduce production costs, the parts of the fixed rod 19 and the movable rod 11 that are directly in contact with the pressure cavity 22 are made of refractory alloys, and the others are made of relatively low-cost high-temperature resistant alloys, which is conducive to reducing production costs. Preferably, the pressure-bearing cavity 22 , the fixed rod 19 and the movable rod 11 are all made of molybdenum alloy, etc. A heat-insulating layer is sprayed on the outer surface of the portion of the fixed rod 19 located in the pressure-bearing cavity 22 .

[0034] Preferably, two groups of synchronously extended resistance wires are arranged around the furnace of the heating furnace 14, one resistance wire is electrically connected to a normally-open power supply 28, and the other resistance wire is electrically connected to a backup power supply 29. Both the normally-open power supply 28 and the backup power supply 29 are equipped with temperature switches 30 for controlling the on and off of the two resistance wires respectively. During normal operation, only the normally-open power supply 28 and the electrical conduction between one of the resistance wires are started, and the other resistance wire and the backup power supply 29 are not energized. The allowable error of the upper and lower limits of the experimental temperature is 1%. In order to keep the experimental temperature within the allowable error range, the temperature switch 30 is electrically connected to the temperature sensor and the temperature controller 25. When the temperature fluctuation in the heating furnace 14 exceeds the set upper or lower limit and lasts for more than 20 seconds, the system will alarm. When the temperature exceeds 1% of the upper limit, the temperature switch 30 associated with the normally-open power supply 28 is disconnected, the heating furnace 14 is powered off and stops working, and is in a furnace-heating state; when the temperature is lower than 1% of the lower limit, the resistance wire connected to the normally-open power supply 28 is suspected to be faulty. To prevent the temperature from continuing to drop and affecting the experimental results, the temperature switch 30 associated with the normally-open power supply 28 is disconnected, and the backup power supply 29 is started and connected to another resistance wire through its associated temperature switch 30 to achieve heating of the heating furnace 14. Preferably, both the normally-open power supply 28 and the backup power supply 29 are provided with a power interface that plugs into the resistance wire.

[0035] Among them, a charging channel 24 for high-pressure gas flow is opened in the fixed rod 19, and a charging port connected to the charging channel 24 is opened on the end wall of the fixed rod 19 corresponding to the refractory metal elastic element 18. The fixed rod 19 is located at the outside of the heating furnace 14 and is provided with an internal pressure interface connected to the charging channel 24. The side wall of the pressure-bearing cavity 22 is provided with an external pressure interface connected to its interior. The external pressure interface is connected to the external pressure pipe 7 extending out of the heating furnace 14, and the external pressure pipe 7 and the internal pressure interface are both connected to the high-pressure inflation mechanism 1.

[0036] As a preferred embodiment of the present invention, a movable rod 11 is provided with one end connected to a driving mechanism, and a refractory metal elastic element 18 is provided between the other end and a fixed rod 19, so that the movable rod 11 moves back and forth under the driving action of the driving mechanism and squeezes the refractory metal elastic element 18, and a vibration frequency detection sensor is provided on the fixed rod 19 to monitor the refractory metal elastic element 18. Furthermore, the heating furnace 14 is used to conduct heat to the pressure-bearing cavity 22 that can transfer heat, so that the required high-temperature environment is formed inside the pressure-bearing cavity 22. The high-pressure inflation mechanism 1 is connected through the external pressure pipe 7 and the internal pressure interface. The high pressure surrounding the outer periphery of the refractory metal elastic element 18 is input into the pressure-bearing cavity 22 through the external pressure pipe 7, and the refractory metal elastic element 18 is compressed by the internal pressure interface and the charging channel 24 and the charging port. The interior of the refractory metal elastic element 18 is pressurized to ensure that a high-pressure environment is maintained inside and outside the refractory metal elastic element 18, and to avoid errors in the test results caused by unbalanced internal and external pressures. The element is plugged and fixed to the pressure-bearing cavity 22 through a fixed rod 19, and the movable rod 11 is sealed and plugged into the pressure-bearing cavity 22 to avoid high pressure leakage at the positions between the side walls of the pressure-bearing cavity 22 and the fixed rod 19 and the movable rod 11, so as to fully reduce the temperature and pressure loss rate and meet the use requirements of special working conditions. The entire pressure cavity 22 has a high temperature resistance upper limit of 1000-1200°C, and the internal and external pressure upper limits are 15MPa. It can accurately obtain test data on factors such as failure and local instability of the refractory metal elastic element 18, and crack initiation and expansion under high temperature and high pressure operating conditions.

[0037] Furthermore, one end of the movable rod 11 extends into the pressure-bearing cavity 22 and is provided with a first pressure plate 17. The end of the fixed rod 19 extending into the pressure-bearing cavity 22 is provided with a second pressure plate 23. A refractory metal elastic element 18 is abutted between the second pressure plate 23 and the first pressure plate 17, and a channel connecting the charging port and the interior of the refractory metal elastic element 18 is opened on the second pressure plate 23. By arranging the first pressure plate 17 and the second pressure plate 23 to increase the contact surface between the movable rod 11 and the fixed rod 19 and the refractory metal elastic element 18 respectively, the refractory metal elastic element 18 of the corresponding structure can be matched without excessively enlarging the cross-section of the movable rod 11 or the fixed rod 19, thereby avoiding the movable rod 11 or the fixed rod 19 having a large cross-section, which leads to a reduction in the sealing performance of the connection with the pressure-bearing cavity 22.

[0038] Furthermore, the portion of the fixing rod 19 extending outside the heating furnace 14 is sleeved with a pad 20, and vibration frequency detection sensors are attached to the four sides of the pad 20. The pad 20 is provided to transmit the vibration frequency of the refractory metal elastic element 18 and the fixing rod 19. The vibration frequency detection sensors attached to the four sides of the pad 20 can detect the vibration frequency at different points and in different directions. When the refractory metal elastic element 18 experiences local instability or overall failure, the signal fed back by the vibration frequency detection sensor exceeds the threshold set under normal system conditions and issues an alarm. The corresponding number of counts at this time represents the fatigue life of the refractory metal elastic element 18 under high-temperature and high-pressure conditions. This method can accurately determine the number of times the test piece experiences local deformation and overall failure. Furthermore, when the refractory metal elastic element 18 experiences local deformation, instability, or failure, the vibration frequency waveform output by the vibration frequency detection sensor exhibits different patterns, allowing the service life of the refractory metal elastic element 18 at different stages to be determined.

[0039] As a preferred embodiment of the present invention, the pad 20 is a ceramic pressure block, which is provided with a through hole for the fixing rod 19 to pass through. The ceramic pressure block is abutted against limiting nuts on both sides along the axial direction of the fixing rod 19, and the limiting nuts are threadedly connected to the fixing rod 19. The ceramic pressure block is provided to ensure its high temperature resistance and heat insulation properties, thereby preventing the vibration frequency detection sensor from being damaged by high temperature, and the abutment of the two limiting nuts is used to ensure the firmness of the connection between the ceramic pressure block and the fixing rod 19.

[0040] Furthermore, the end of the fixing rod 19 extending out of the ceramic pressing block and the limit nut is threadedly connected to a heat dissipation rod. A heat dissipation blind hole is provided at the end of the heat dissipation rod away from the ceramic pressing block. A plurality of heat dissipation holes connected to the heat dissipation blind holes are provided on the outer peripheral wall of the heat dissipation rod. By providing heat dissipation blind holes on the heat dissipation rod to expand its contact surface with the outside air, the heat dissipation efficiency is improved. By providing heat dissipation holes on the heat dissipation rod, the heat dissipation blind holes form a rapid flow of air with the outside through the heat dissipation holes, thereby improving the heat exchange efficiency and ensuring that the fixing rod 19 does not suffer excessive thermal deformation. Preferably, the heat dissipation rod has multiple groups of heat dissipation holes along its axial direction, each group of heat dissipation holes is evenly spaced, each group of heat dissipation holes includes three heat dissipation holes, and each heat dissipation hole is evenly distributed along the circumference of the heat dissipation rod, which can ensure the strength requirements of the heat dissipation rod and the heat dissipation effect.

[0041] Furthermore, a first metal bellows 12 is sealed between the inner wall of the pressure-bearing cavity 22 for the movable rod 11 to be inserted and the first pressure plate 17. The first metal bellows 12 is sleeved on the outer peripheral side of the movable rod 11 to seal the gap between the movable rod 11 and the pressure-bearing cavity 22, thereby ensuring the pressure inside the pressure-bearing cavity 22. Preferably, the two ends of the first metal bellows 12 are welded to the first pressure plate 17 and the inner wall of the pressure-bearing cavity 22, respectively. And preferably, the refractory metal elastic element 18 is a metal bellows, and the two ends of the metal bellows are welded to the first pressure plate 17 and the second pressure plate 23, respectively. In order to meet different stroke requirements, the wave numbers of the first metal bellows 12 and the metal bellows can be different. The first metal bellows 12 only needs to meet the sealing and pressure-maintaining function during the movement. And it should be noted that the setting of the movement stroke of the movable rod 11 does not exceed the maximum compensable displacement of the first metal bellows 12 and the metal bellows.

[0042] Preferably, a clamp 13 is fixed on the outer wall of the pressure-bearing cavity 22, and the clamp 13 is sleeved on the movable rod 11 and slidably connected to the movable rod 11. The clamp 13 is used to tightly encircle the reciprocating movable rod 11, guide and limit the movable rod 11, thereby enhancing the rigidity of the movable rod 11 and avoiding the instability of the slender movable rod 11 during operation. As a preferred embodiment, the clamp 13 includes a pair of connecting parts, the two connecting parts are connected to form a circular structure, and are slidably sleeved on the outer peripheral wall of the movable rod 11.

[0043] Furthermore, a second metal bellows 16 is connected between the external pressure interface and the external pressure pipeline 7. The second metal bellows 16 plays the role of high-temperature and high-pressure displacement compensation to prevent large rigid deformation of the local system. One end of the second metal bellows 16 is welded to the external pressure interface of the pressure-bearing cavity 22, and the other end extends out of the heating furnace 14 and is connected to the external pressure pipeline 7. The second metal bellows 16 itself has the function of high-temperature displacement compensation, which can prevent stress concentration caused by high-temperature rigid connection. Avoid using a rigid elbow structure to connect the external pressure interface and the external pressure pipeline 7, as there is a risk of damage due to high temperature and high pressure. Preferably, a straight pipe section 15 is welded at the external pressure interface to facilitate the second metal bellows 16 to be sleeved and fixed on the straight pipe section 15 to achieve communication with the pressure-bearing cavity 22.

[0044] Moreover, the internal pressure interface is connected to an internal pressure pipe 8, and the internal pressure pipe 8 and the external pressure pipe 7 are connected in parallel at the outlet of the high-pressure inflation mechanism 1, and a heat exchanger 9 is provided on each of the internal pressure pipe 8 and the external pressure pipe 7 to dissipate heat therefrom. The function of the two heat exchangers 9 is to reduce the risk of sealing leakage. Because the fatigue life test takes a long time, heat transfer will occur from the heated end to the inflation end. If the heat exchanger 9 is not added to cool down, it will cause the inflation end to overheat. When the temperature is too high, it will inevitably cause the joint sealing performance to deteriorate, causing leakage. Then, by providing the heat exchanger 9, local gas leakage caused by heat transfer is avoided and the pressure maintenance effect is enhanced. Preferably, the heat exchanger 9 is a rectangular parallelepiped structure, and a gas flow channel is provided through the middle part of the heat exchanger 9. The gas flow channel is connected to the external pressure pipe 7 or the internal pressure pipe 8. The outer periphery of the gas flow channel is surrounded by a plurality of water channels. The heat exchanger 9 is provided with a plurality of pairs of water inlets and water return ports connected to each water channel on both sides of the radial direction of the gas flow channel. Preferably, a pressure gauge 4 is provided on the internal pressure pipe 8 and the external pressure pipe 7. When the pressure gauge 4 shows that the pressure of the pressure chamber 22 drops by more than 5%, it indicates that the first metal bellows 12 is leaking, its pressure-maintaining function is lost, the proximity switch stops counting, the experiment stops, and the device needs to be repaired and re-implemented.

[0045] The high-pressure inflation mechanism 1 uses only one, preferably a nitrogen cylinder, which is divided into an internal pressure pipe 8 and an external pressure pipe 7 by a distributor 3. The external pressure pipe 7 extends into the pressure-bearing cavity 22 to provide external pressure to the refractory metal elastic element 18. The internal pressure pipe 8 is connected to the charging channel 24 in the fixed rod 19 to provide internal pressure to the refractory metal elastic element 18. Preferably, a main valve 2 is provided between the distributor 3 and the high-pressure inflation mechanism 1, and a first distribution valve 5 and a second distribution valve 6 are provided between the distributor 3 and the internal pressure pipe 8 and the external pressure pipe 7, respectively.

[0046] The vibration frequency detection sensor is electrically connected to an oscilloscope 21 for enhancing the signal characteristic value. Since the fixing rod 19 and the pressure-bearing cavity 22 are welded and fastened, the vibration frequency signal is easily attenuated by the pressure-bearing cavity 22. The horizontal and vertical coordinate display adjustment function of the oscilloscope 21 itself is used to amplify the frequency signal to enhance the contrast effect of the signal characteristic value. As a preferred option, signal amplification can also be achieved through a signal amplifier.

[0047] Preferably, the heating furnace 14 has a cylindrical structure with openings at both ends, and a top cover 26 and a bottom cover 27 are fixed to the top and bottom ends respectively. The pressure cavity 22 is located in the space surrounded by the heating furnace 14, the top cover 26 and the bottom cover 27. The movable rod 11 and the fixed rod 19 pass through the top cover 26 and the bottom cover 27 respectively, and the clamp 13 is fixed to the top cover 26.

[0048] Adaptive changes based on actual needs are all within the scope of protection of the present invention.

[0049] It should be noted that it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0050] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A fatigue life measuring device for refractory metal elastic elements, characterized in that: It comprises a pressure-bearing cavity and a heating furnace surrounding the outer peripheral side of the pressure-bearing cavity, a movable rod is slidably and sealedly inserted on the pressure-bearing cavity, one end of the movable rod extends out of the heating furnace and is connected to a driving mechanism that drives the movable rod to move back and forth, and the other end extends into the pressure-bearing cavity, a fixed rod is inserted on the inner wall of the pressure-bearing cavity opposite to the movable rod, the fixed rod is coaxially arranged with the movable rod, one end of the fixed rod extends into the pressure-bearing cavity, and a refractory metal elastic element abuts against the movable rod, and the other end extends out of the pressure-bearing cavity and the heating furnace, and is connected to a vibration frequency detection sensor; A charging channel for high-pressure gas to flow is provided in the fixing rod, a charging port connected to the charging channel is provided on the end wall of the fixing rod corresponding to the inside of the refractory metal elastic element, an internal pressure interface connected to the charging channel is provided on the fixing rod at a position outside the heating furnace, an external pressure interface connected to the interior of the pressure-bearing cavity is provided on the side wall of the pressure-bearing cavity, the external pressure interface is connected to an external pressure pipeline extending out of the heating furnace, and both the external pressure pipeline and the internal pressure interface are connected to a high-pressure inflation mechanism.

2. The refractory metal elastic element fatigue life measuring device according to claim 1, characterized in that: One end of the movable rod extends into the pressure-bearing cavity and is provided with a first pressure plate, and the end of the fixed rod extending into the pressure-bearing cavity is provided with a second pressure plate, the refractory metal elastic element is abutted between the second pressure plate and the first pressure plate, and the second pressure plate is provided with a channel connecting the charging port and the interior of the refractory metal elastic element.

3. The fatigue life measuring device of refractory metal elastic element according to claim 2, characterized in that: The portion of the fixing rod extending out of the heating furnace is sleeved with a cushion block, and the vibration frequency detection sensor is attached to all four sides of the cushion block.

4. The refractory metal elastic element fatigue life measuring device according to claim 3, characterized in that: The cushion block is a ceramic pressing block, which is provided with a through hole for the fixing rod to pass through, and both sides of the ceramic pressing block along the axis direction of the fixing rod are abutted against limiting nuts, and the limiting nuts are threadedly connected to the fixing rod.

5. The fatigue life measuring device of refractory metal elastic element according to claim 4, characterized in that: The end of the fixing rod extending out of the ceramic pressing block and the limiting nut is threadedly connected with a heat dissipation rod, and a heat dissipation blind hole is opened at one end of the heat dissipation rod away from the ceramic pressing block, and a plurality of heat dissipation holes connected with the heat dissipation blind hole are opened on the outer peripheral wall of the heat dissipation rod.

6. The refractory metal elastic element fatigue life measuring device according to claim 5, characterized in that: A first metal bellows is sealed between the inner wall of the pressure-bearing cavity for the movable rod to be inserted and the first pressure plate, and the first metal bellows is sleeved on the outer peripheral side of the movable rod.

7. The fatigue life measuring device of refractory metal elastic element according to claim 6, characterized in that: A clamp is fixed on the outer wall of the pressure-bearing cavity, and the clamp is sleeved on the movable rod and is slidably connected with the movable rod.

8. The fatigue life measuring device of refractory metal elastic element according to claim 7, characterized in that: A second metal bellows is connected between the external pressure interface and the external pressure pipeline.

9. The fatigue life measuring device of refractory metal elastic element according to claim 8, characterized in that: The internal pressure interface is connected to an internal pressure pipeline, the internal pressure pipeline and the external pressure pipeline are connected in parallel at the air outlet of the high-pressure inflation mechanism, and the internal pressure pipeline and the external pressure pipeline are both provided with heat exchangers for dissipating heat respectively.

10. The refractory metal elastic element fatigue life measuring device according to claim 9, characterized in that: Two groups of synchronously extending resistance wires are arranged around the furnace of the heating furnace, one of the resistance wires is electrically connected to a normally open power supply, and the other resistance wire is electrically connected to a backup power supply. Both the normally open power supply and the backup power supply are equipped with temperature switches for respectively controlling the on and off of the two resistance wires.

Images