A test bench for testing the sealing performance of centrifugal compressors

Abstract

The invention relates to the technical field of sealing performance testing, and discloses a test bench for testing the sealing performance of a centrifugal compressor, comprising an air filling pipe, an air collecting pipe and an air collecting bottle, wherein a centrifugal compressor to be tested is arranged between the air filling pipe and the air collecting pipe, the air filling pipe is connected to the air inlet pipe of the centrifugal compressor, the air collecting pipe is connected to the air outlet pipe of the centrifugal compressor, the upper and lower ends of the air filling pipe are respectively fixedly connected with air supply pipes, the two air supply pipes are commonly connected to an air filling box, the air supply pipes are respectively connected to the two sides of the opposite surface of the air filling box, an air cavity is arranged inside the air filling box, a push plate is slidably arranged inside the air cavity, and an air filling structure which is connected to the air cavity and can only take in air in one direction is arranged at both ends of the air filling box; the test bench for testing the sealing performance of the centrifugal compressor can detect the sealing performance of the centrifugal compressor during the working process of the centrifugal compressor by starting a fan cycle to fill the centrifugal compressor with air and then collecting it through the air collecting bottle, and by detecting the volume size of the corresponding gas in the air collecting bottle after compression.

Description

Technical Field

[0001] The invention relates to the technical field of sealing performance testing, in particular to a test bench for sealing performance testing of a centrifugal compressor. Background Art

[0002] A centrifugal compressor is a device that compresses gas by the principle of centrifugal force. It mainly consists of a rotating impeller and a diffuser. After the gas enters the compressor, it is captured by the high-speed rotating impeller and accelerated under the action of centrifugal force, thereby increasing the kinetic energy of the gas. Subsequently, the gas enters the diffuser, where the kinetic energy is converted into pressure energy, thereby achieving gas compression. Centrifugal compressors are widely used in gas compression and processing due to their high efficiency, stability and suitability for large flow rates. The main engine of a centrifugal compressor usually adopts three-stage gas compression, and each stage uses a labyrinth seal to prevent gas leakage. However, due to the gap between the labyrinth seal and the main shaft, gas leakage in the centrifugal compressor is inevitable, but if the sealing is poor, the gas leakage will be large. When the gas leakage reaches 1% to 3% of the total exhaust volume of the compressor, it will affect the exhaust performance of the compressor. In addition, if the leakage increases further, it will not only lead to a decrease in energy efficiency, but also increase the risk of wear and damage to the equipment. At the same time, leakage may bring serious safety hazards. For example, in a nitrogen centrifugal compressor, if the nitrogen leakage is too large, it will not only affect the performance of the equipment, but also pose a safety risk, causing equipment failure or personal injury.

[0003] Existing centrifugal compressor sealing performance test equipment usually adopts static pressure difference method or gas detection method. The static pressure difference method determines the sealing performance by applying a certain pressure when the centrifugal compressor is stationary and then detecting the pressure change. The gas detection method is to place a specific gas in the centrifugal compressor and then determine the sealing performance by detecting the gas leakage. However, when the centrifugal compressor is in working state, this traditional detection equipment cannot be used, because the centrifugal compressor is in high-speed rotation in the working state, and the centrifugal force and vibration generated make it difficult for the static pressure difference method to accurately measure the sealing performance, and under the high-speed rotation state, the distribution and flow of the internal gas will change significantly, and the gas detection method is difficult to obtain accurate leakage data under such conditions. If the sealing performance of the centrifugal compressor in the working state cannot be detected, it will cause safety problems in the subsequent working process of the centrifugal compressor, and even if the existing test equipment can perform sealing detection on the centrifugal compressor in the working state, after the gas passes through the centrifugal compressor, the gas will change in temperature due to compression effect, friction heat generation, heat conduction and phase change effect in the centrifugal compressor, resulting in changes in the temperature of the exhaust gas and the temperature of the incoming gas, which will affect the accuracy of the sealing performance test. Summary of the invention

[0004] (I) Technical problems to be solved: In view of the deficiencies in the prior art, the present invention provides a test bench for testing the sealing performance of centrifugal compressors, which has the advantages of being able to detect the sealing performance of a centrifugal compressor in a working state and being able to dynamically correct the temperature of the collected gas to improve the test accuracy. It solves the problem that the existing centrifugal compressor sealing performance testing equipment can only perform sealing performance tests on centrifugal compressors in a stationary state, but cannot perform sealing tests on centrifugal compressors in a working state, and that the temperature of the gas in the centrifugal compressor changes due to compression effect, frictional heat generation, heat conduction and phase change effect, resulting in changes in the temperature of the exhaust gas and the temperature of the incoming gas, which affects the test results.

[0005] (II) Technical solution: In order to achieve the above-mentioned purpose of being able to detect the sealing performance of a centrifugal compressor in a working state and being able to dynamically correct the temperature of the collected gas to improve the test accuracy, the present invention provides the following technical solution: a test bench for testing the sealing performance of a centrifugal compressor, comprising an air filling pipe, an air collecting pipe and an air collecting bottle, a centrifugal compressor to be tested is arranged between the air filling pipe and the air collecting pipe, the air filling pipe is connected to the air inlet pipe of the centrifugal compressor, the air collecting pipe is connected to the air outlet pipe of the centrifugal compressor, and the air filling pipe is provided with a gas collecting bottle. The air box is provided with a T-shaped tube, and the upper and lower ends of the inflation tube are respectively fixedly connected with an air supply pipe, and the two air supply pipes are commonly connected with an inflation box, and the air supply pipes are respectively connected to the two sides of the opposite surfaces of the inflation box, and an air cavity is provided inside the inflation box, and a push plate is slidably provided in the air cavity, and an inflation structure which is connected to the air cavity and can only take in air in one direction is provided at both ends of the inflation box; the inflation structures at both ends cyclically inflate the air cavity in turn, and the wind pressure generated by the inflation structure pushes the push plate to move back and forth along the air cavity and squeezes the gas in the air cavity along the air supply pipe and the inflation pipe into the centrifugal compressor.

[0006] Preferably, the inflation structure includes a fixed tube, a fan, and a telescopic filter element. The fixed tubes are fixedly arranged at both ends of the inflation box and communicated with the air cavity. The fan is coaxially fixedly installed in the fixed tube. When the telescopic filter element contracts, the filtering resistance of the filter element increases, and when the telescopic filter element extends, the filtering resistance of the filter element decreases. A flexible telescopic ring is also coaxially fixedly connected around the telescopic filter element. A ring-shaped wind resistance cavity is opened on the telescopic ring. The telescopic ring is fixedly arranged in the fixed tube, and the wind resistance cavity faces the air outlet direction of the fan. When air is filled in the wind resistance cavity, the telescopic ring and the telescopic filter element are driven to extend along the direction of the fixed tube.

[0007] Preferably, a control valve is also installed between the inflation pipe and the gas delivery pipe.

[0008] Preferably, a cooling pipe is coaxially sleeved on the air collecting pipe, the diameter of the cooling pipe is larger than the diameter of the air collecting pipe, an air flow cavity is arranged between the cooling pipe and the air collecting pipe, the cooling pipe comprises an air inlet end and an air outlet end, the air inlet end is provided with a cold air pipe connected to the air flow cavity, the air outlet end is connected to the external environment, the air inlet end of the cooling pipe is in the shape of a funnel with a gradually increasing diameter, a temperature-sensitive spring which can change its own telescopic length as its own temperature changes is arranged in the air flow cavity, and the temperature-sensitive spring is attached to the surface of the air collecting pipe One end of the temperature-sensitive spring is fixedly arranged on the outer surface of the gas collecting pipe, and the other end of the temperature-sensitive spring is provided with a piston ring that can slide relative to the gas collecting pipe, and the expansion and contraction direction of the piston ring is toward the funnel-shaped side of the cooling pipe, the major diameter of the piston ring is equal to the inner diameter of the cooling pipe, and the minor diameter of the piston ring is equal to the outer diameter of the gas collecting pipe; the initial position of the piston ring is located on the non-funnel-shaped side of the cooling pipe, and when the temperature of the temperature-sensitive spring rises due to heat, the piston ring enters the funnel-shaped cooling pipe.

[0009] Preferably, the temperature-sensitive spring is made of a thermosensitive material or a shape memory alloy.

[0010] Preferably, both ends of the air cavity are provided with limiting structures attached to the surface of the air cavity, a gap is left between the limiting structure and the inflation structure, and the connection position between the air delivery pipe and the air cavity is arranged between the gaps.

[0011] Preferably, the cold air pipe injects cooling gas at constant pressure into the air flow cavity.

[0012] Preferably, the telescopic ring is made of flexible material.

[0013] (III) Beneficial effects: Compared with the prior art, the present invention provides a test bench for testing the sealing performance of centrifugal compressors, which has the following beneficial effects: 1. The test bench for testing the sealing performance of centrifugal compressors, through the coordinated use of an air filling box structure, a push plate structure, and a fan structure, is compared with a traditional structure that can only test the sealing performance of a centrifugal compressor in a stationary state. The test bench for testing the sealing performance of a centrifugal compressor in the present invention adopts a mode in which a fan is started cyclically to continuously inflate the centrifugal compressor in a working state and collects the gas through a gas collecting bottle. By detecting the volume of the corresponding gas after compression in the gas collecting bottle, the sealing performance of the centrifugal compressor can be detected during the working process of the centrifugal compressor. In this process, if the sealing performance of the centrifugal compressor is poor, the gas leakage is large, and the total volume of the gas collected in the gas collecting bottle is proportional to the gas volume of the inflation structure. The amount of gas filled into the structure will be significantly reduced compared to the original structure. Therefore, by detecting the reduced volume of gas in the gas collecting bottle, the degree of leakage of the centrifugal compressor during operation can be determined, thereby detecting its sealing performance under working conditions. At the same time, by setting the fans to start alternately in a cycle, when the fan at one end is started, the fan at the other end is in a stopped state, so that each fan has time to cool down, avoiding overheating problems caused by long-term continuous operation, thereby protecting the fan motor and extending the service life of the equipment. In addition, since the gas pipes at both ends alternately transport gas to the centrifugal compressor, this reciprocating motion ensures that the gas transmission process is continuous. Compared with the working mode of a single fan, the alternately started fan can stop at one end while the other end continues to work, avoiding interruptions in the gas transmission process, thereby improving the overall gas transmission efficiency and enabling the centrifugal compressor to obtain a continuous and stable gas supply.

[0014] 2. The test bench for testing the sealing performance of centrifugal compressors uses a fan structure, a telescopic filter element structure, a telescopic ring structure, and a wind resistance chamber structure in coordination. Compared with the traditional technical structure, which needs to set up filter elements and gas valves separately, the structure is complex and multi-faceted. Due to the presence of the telescopic filter element, the test bench for testing the sealing performance of centrifugal compressors can reduce impurities by filtering the gas through the telescopic filter element when extracting gas from the external environment, and the structure of the telescopic filter element allows it to filter and ventilate only from one side. When the fan on one side is running, only the telescopic filter element on this side is in an extended state and its gas resistance is small, so the wind generated by the fan can pass through. On the other side, since the telescopic ring is not in an extended state, the telescopic filter element is in a contracted state at this time, and the gas resistance is greater than the gas resistance of the gas pipe. The gas in the air cavity can only be discharged from the gas pipe, thereby avoiding leakage from the fan side to affect the test results. In addition, this structure does not require additional drive structures and control structures. Not only is the structure itself simple, but it also realizes the function of the gas valve for gas filtration, simplifies the structure, and greatly reduces the cost of equipment use.

[0015] 3. The test bench for testing the sealing performance of centrifugal compressors uses a cold air pipe structure. Compared with the traditional technical structure, during the process of collecting gas, the gas will be affected by the centrifugal compressor during the discharge process, causing its temperature to change. The temperature-sensitive spring in the test bench structure for testing the sealing performance of centrifugal compressors automatically adjusts its length according to the temperature change of the collecting pipe surface, pushing the piston ring to move. When the gas temperature rises, the temperature-sensitive spring extends, and the piston ring enters the funnel-shaped cooling pipe, increasing the channel for cold air to flow into the air flow cavity and enhancing the cooling effect. When the gas temperature decreases, the temperature-sensitive spring contracts, the piston ring retreats, reducing the cold air flow channel and reducing the cooling intensity. This function realizes dynamic adjustment of the cooling intensity and improves the cooling efficiency. Traditional cooling equipment usually works at a fixed cooling intensity, which easily causes energy waste. The temperature-sensitive spring and piston ring design only enhance the cooling effect when the gas temperature is high, and reduce the cooling intensity when the gas temperature is low, avoiding unnecessary cooling process, thereby saving energy. In addition, the temperature-sensitive spring can realize the start and close of the cold air pipe without an additional driving structure, further simplifying the system design and greatly reducing the system complexity and maintenance difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the test bench for testing the sealing performance of a centrifugal compressor in the present invention.

[0017] Figure 2 It is a structural front view of the test bench for testing the sealing performance of a centrifugal compressor in the present invention.

[0018] Figure 3 The figure is a structural side view of the test bench for testing the sealing performance of a centrifugal compressor in the present invention.

[0019] Figure 4 The figure is a top view of the structure of the test bench for testing the sealing performance of a centrifugal compressor in the present invention.

[0020] Figure 5 It is a structural cross-sectional view of the test bench for testing the sealing performance of a centrifugal compressor in the present invention.

[0021] Figure 6 This is a cross-sectional view of the cooling pipe structure of the test bench used for testing the sealing performance of a centrifugal compressor in the present invention.

[0022] Figure 7 It is a cross-sectional view of the temperature-sensing spring structure in the cooling tube of the test bench for testing the sealing performance of the centrifugal compressor in the present invention after being heated.

[0023] Figure 8 It is a schematic diagram of the three-dimensional structure of the air filling box of the test bench for testing the sealing performance of the centrifugal compressor in the present invention.

[0024] Fig. 9 It is a cross-sectional view of the left end fan of the air filling box structure of the test bench for testing the sealing performance of the centrifugal compressor in the present invention when it is started.

[0025] Fig.10 It is a cross-sectional view of the right end fan of the inflation box structure of the test bench for testing the sealing performance of the centrifugal compressor in the present invention when it is started.

[0026] In the figure: 1-inflating pipe, 2-gas collecting pipe, 3-gas collecting bottle, 4-centrifugal compressor, 5-gas transmission pipe, 600-inflating box, 601-air cavity, 602-push plate, 603-limiting structure, 700-fixed pipe, 701-fan, 800-telescopic filter element, 801-telescopic ring, 802-wind resistance cavity, 900-cooling pipe, 901-air flow cavity, 902-cold air pipe, 903-temperature sensing spring, 904-piston ring, 10-control valve. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0028] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5A test bench for testing the sealing performance of a centrifugal compressor comprises an air filling pipe 1, an air collecting pipe 2 and an air collecting bottle 3. A centrifugal compressor 4 to be tested is arranged between the air filling pipe 1 and the air collecting pipe 2. The air filling pipe 1 is connected to the air inlet pipe of the centrifugal compressor 4, and the air collecting pipe 2 is connected to the air outlet pipe of the centrifugal compressor 4. The air filling pipe 1 is arranged as a T-shaped pipe. The T-shaped pipe design can evenly distribute the gas to various parts of the centrifugal compressor 4, thereby ensuring the uniformity of the gas pressure during the test and improving the accuracy of the test. The T-shaped pipe allows gas to enter the centrifugal compressor 4 from both sides, ensuring the continuity and stability of the gas supply and avoiding uneven pressure caused by unilateral gas supply. The upper and lower ends of the air filling pipe 1 are respectively fixedly connected with air supply pipes 5, and the two air supply pipes 5 are commonly connected to an air filling box 600. The air supply pipes 5 are respectively connected to the two sides of the opposite surface of the air filling box 600. By connecting the air supply pipes 5 to the two sides of the air filling box 600, a balanced distribution of the air flow can be achieved, ensuring that the air pressure on one side will not be too high or too low during the inflation process, thereby improving the overall gas supply efficiency. The design of alternating air supply on both sides ensures the continuity of gas supply, so that the centrifugal compressor 4 is always in a stable air pressure environment during the test. An air cavity 601 is arranged inside the air box 600, and a push plate 602 is slidably arranged inside the air cavity 601. Both ends of the air box 600 are provided with an inflatable structure that is connected to the air cavity 601 and can only intake air in one direction. The one-way air intake structure can prevent gas backflow, ensuring that the gas can only enter the air cavity 601 each time the fan 701 is started, avoiding the damage of the fan 701 and the equipment due to the reverse airflow. The one-way air intake ensures the stability of the air pressure in the air cavity 601, thereby ensuring that the push plate 602 is evenly stressed during the reciprocating motion, improving the reliability and measurement accuracy of the equipment; the inflatable structures at both ends cyclically inflate the air cavity 601 in turn, and the wind pressure generated by the inflatable structure pushes the push plate 602 to move back and forth along the air cavity 601 and squeezes the gas in the air cavity 601 along the air pipe 5 and the inflatable pipe 1 into the centrifugal compressor 4. A control valve 10 is also installed between the inflation pipe 1 and the gas delivery pipe 5. The control valve 10 is used to accurately control the direction and flow of the air flow, ensure that the gas enters the centrifugal compressor 4 according to the predetermined path, avoid the chaotic flow of gas between different pipes, and thus ensure the accuracy of the test results. When the fan 701 at one end is inhaled, the control valve 10 closes the air intake pipe at the other end to prevent gas leakage from the non-working end, thereby improving the rigor of the test. A limiting structure 603 attached to the surface of the air cavity 601 is also provided at both ends of the air cavity 601. A gap is left between the limiting structure 603 and the inflation structure. The connection position of the gas delivery pipe 5 and the air cavity 601 is set between the gaps. The gap can prevent the push plate 602 from being completely pushed to one side of the air cavity 601, thereby causing adsorption and affecting efficiency, thereby ensuring that the push plate 602 can move back and forth smoothly and improve the smoothness of the equipment operation. The limiting structure 603 can limit the moving range of the push plate 602, prevent the push plate 602 from exceeding the design stroke, and protect the push plate 602 and the equipment from damage.

[0029] See also Figure 1 , Figure 4 , Figure 5 , Figure 8 , Fig. 9 , Fig.10 The inflatable structure includes a fixed tube 700, a fan 701, and a telescopic filter element 800. The fixed tube 700 is fixedly arranged at both ends of the inflatable box 600 and communicated with the air cavity 601. The fan 701 is coaxially fixedly installed in the fixed tube 700. The fixed tube 700 is fixedly arranged at both ends of the inflatable box 600 and communicated with the air cavity 601 to ensure the stability of the airflow path and improve the airflow transmission efficiency. The fan 701 is coaxially fixedly installed in the fixed tube 700, which can effectively concentrate the airflow, reduce the airflow loss, and ensure the stable supply of gas. This design makes the maximum use of the space in the inflatable box 600, ensures the reasonable layout of the fan 701 and the fixed tube 700, and makes the whole system more compact. When the telescopic filter element 800 is contracted, the filter element filtration resistance increases, and when the telescopic filter element 800 is extended, the filter element filtration resistance decreases. This design allows the filter element to dynamically adjust its filtration resistance according to the airflow demand. When a larger airflow is required, the filter element is extended to reduce the resistance. Conversely, when the airflow needs to be reduced, the filter element is contracted to increase the resistance. In this way, more efficient filtration can be provided when needed, ensuring that the gas entering the device is clean, protecting the internal structure of the device, and extending the life of the device. A flexible telescopic ring 801 is coaxially fixedly connected around the telescopic filter element 800. The telescopic ring 801 provides a stable frame to ensure that the telescopic filter element 800 maintains a uniform shape during the telescopic process without displacement or deformation. An annular wind resistance chamber 802 is provided on the telescopic ring 801. The telescopic ring 801 is fixedly arranged in the fixed tube 700, and the wind resistance chamber 802 faces the air outlet direction of the fan 701. The wind resistance chamber 802 is designed to face the air outlet direction of the fan 701, so that the airflow generated by the fan 701 can directly enter the wind resistance chamber 802, and the airflow is used to promote the extension of the telescopic ring 801 and the filter element. This design enables the telescopic ring 801 and the filter element to automatically adjust their length according to changes in the airflow, thereby adjusting the filtering effect and airflow resistance, and improving the automation and intelligence level of the system. When the wind resistance chamber 802 is filled with air, the telescopic ring 801 and the telescopic filter element 800 are driven to extend in the direction of the fixed tube 700. The telescopic ring 801 is made of a flexible material. The flexible material can better adapt to the shape change of the air cavity 601, wherein the flexible material of the telescopic ring 801 is used, wherein the resistance of the telescopic filter element 800 when contracting is much greater than the resistance of the air delivery pipe 5, and also much greater than the expansion resistance of the wind resistance chamber 802.

[0030] See also Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 6 and Figure 7 , Figure 7The direction of the middle arrow is the expansion and contraction direction of the temperature-sensitive spring 903 after being heated. A cooling tube 900 is also coaxially sleeved on the gas collecting tube 2. The diameter of the cooling tube 900 is larger than the diameter of the gas collecting tube 2, forming an air flow cavity 901, so that the cooling gas can flow in the air flow cavity 901 and fully exchange heat with the surface of the gas collecting tube 2, thereby improving the cooling effect. Increasing the diameter of the cooling tube 900 helps to slow down the gas flow rate, provide a longer cooling time, and enable the gas to dissipate heat more effectively. An air flow cavity 901 is arranged between the cooling tube 900 and the gas collecting tube 2. The cooling tube 900 includes an air inlet end and an air outlet end. The air inlet end is provided with a cold air pipe 902 connected to the air flow cavity 901, and the cold air pipe 902 injects constant pressure cooling gas into the air flow cavity 901. The air outlet is connected to the external environment, and the air inlet end of the cooling tube 900 is in the shape of a funnel with a gradually increasing diameter. A temperature-sensitive spring 903 is provided in the air flow cavity 901, which can change its own telescopic length as its own temperature changes. The temperature-sensitive spring 903 can automatically adjust its length according to the gas temperature, thereby changing the position of the piston ring 904, adjusting the flow of cold air, and realizing dynamic adjustment of the cooling intensity to ensure that the gas is within a suitable temperature range. This design avoids unnecessary overcooling and only increases the cooling intensity when necessary, thereby reducing energy waste and improving the energy efficiency of the system. The temperature-sensitive spring 903 is attached to the surface of the gas collecting pipe 2. The temperature-sensitive spring 903 is attached to the surface of the gas collecting pipe 2 and can directly sense the temperature changes of the gas, ensuring that the temperature-sensitive spring 903 can respond to temperature changes in a timely manner and accurately adjust the cooling intensity. The attachment design reduces the temperature conduction path, allowing the temperature-sensitive spring 903 to sense and respond to temperature changes more quickly, thereby improving the response speed of the system. One end of the temperature-sensing spring 903 is fixedly arranged on the outer surface of the gas collecting pipe 2, and the other end of the temperature-sensing spring 903 is provided with a piston ring 904 that can slide relative to the gas collecting pipe 2, and the expansion and contraction direction of the piston ring 904 is toward the funnel-shaped side of the cooling pipe 900, the major diameter of the piston ring 904 is equal to the inner diameter of the cooling pipe 900, and the minor diameter of the piston ring 904 is equal to the outer diameter of the gas collecting pipe 2. The piston ring 904 can slide under the drive of the temperature-sensing spring 903, change the cold air flow in the airflow cavity 901, and automatically adjust the cooling intensity. The design of the major diameter being equal to the inner diameter of the cooling pipe 900 and the minor diameter being equal to the outer diameter of the gas collecting pipe 2 ensures the sealing of the piston ring 904 at different positions. When the temperature-sensing spring 903 contracts, the piston ring 904 retreats, reducing the inflow of cold air and preventing the gas temperature from being too low, thereby optimizing the cooling efficiency and saving energy. This design simplifies the system structure and does not require additional drive and control devices, making the system more reliable and reducing maintenance difficulty and cost; the initial position of the piston ring 904 is located on the non-funnel-shaped side of the cooling tube 900. When the temperature of the temperature-sensitive spring 903 is heated, the piston ring 904 enters the funnel-shaped cooling tube 900. The temperature-sensitive spring 903 is made of a thermosensitive material or a shape memory alloy.

[0031] Working principle: When using the device to test the sealing performance of the centrifugal compressor 4 during operation, first connect the air charging pipe 1 of the device to the air inlet pipe of the centrifugal compressor 4, and connect the air collecting pipe 2 to the air outlet pipe of the centrifugal compressor 4. After confirming the sealing of the connection, start the device, and the fans 701 at both ends of the air charging box 600 will periodically and alternately inflate the air cavity 601. During the start-up process of the fan 701, since the telescopic filter element 800 is in a contracted state in the initial state, the gas encounters a large resistance when passing through the contracted telescopic filter element 800. Therefore, most of the gas will enter the wind resistance cavity 802. Since the telescopic resistance of the wind resistance cavity 802 is much smaller than that of the telescopic filter element 800 when contracted, a large amount of gas will enter the wind resistance cavity 802, causing the telescopic ring 801 to stretch. When the telescopic ring 801 stretches, the telescopic filter element 800 will also stretch together, thereby increasing the gas resistance of the telescopic filter element 800. Reduced, at this time, the gas can enter the air cavity 601 through the telescopic filter element 800. When the gas enters the air cavity 601, the air pressure in the air cavity 601 on the side where the fan 701 is started will increase, thereby pushing the push plate 602 to move in the blowing direction of the fan 701. During the movement of the push plate 602, the gas in the air cavity 601 on the other side of the push plate 602 will be squeezed. Since the fan 701 on the other side is not started, the telescopic filter element 800 on the other side is in a telescopic state, and its gas passing resistance is much greater than the gas resistance in the direction of the gas pipe 5. Therefore, after being squeezed, the gas will enter the inflation pipe 1 along the gas pipe 5, and then enter the centrifugal compressor 4 from the inflation pipe 1. When the baffle moves to the position of the limiting structure 603, the fan 701 away from the limiting structure 603 stops, and then the fan 701 close to the baffle starts, and the above-mentioned working process is circulated. Among them, when the gas pipe 5 at one end is inhaled, the control valve 10 located at the other end of the intake pipe is closed.

[0032] When the gas is discharged from the centrifugal compressor 4 and passes through the gas collecting pipe 2, since the temperature of the gas is different from the initial temperature after being compressed by the centrifugal compressor 4, it is necessary to restore its temperature to the initial temperature. The gas temperature that has changed in the gas collecting pipe 2 can be restored through the cold air pipe 902. The specific principle is that when the gas passes through the gas collecting pipe 2, the surface temperature of the gas collecting pipe 2 will change. When the surface temperature of the gas collecting pipe 2 changes, it will cause the temperature sensitive spring 903 to expand and contract. When the temperature rises, the temperature sensitive spring 903 will expand and contract, thereby pushing the piston ring 904 to move toward the funnel-shaped end of the cooling pipe 900. When the piston ring 904 moves to the funnel-shaped area, the diameter of the cooling pipe 900 gradually increases. At this time, the piston Ring 904 cannot completely block the movement of cold air in the funnel-shaped area. The cold air will pass through the airflow cavity 901 through the gap between the piston ring 904 and the cooling tube 900. When the cold air passes through the airflow cavity 901, it will exchange heat with the surface of the gas collecting pipe 2, thereby reducing the gas temperature inside the gas collecting pipe 2 to the initial temperature. When the gas temperature in the gas collecting pipe 2 decreases, the temperature-sensitive spring 903 will recover, and the gap between the piston ring 904 and the cooling tube 900 will gradually decrease, causing the airflow in the airflow cavity 901 to gradually decrease.

[0033] In the above working process, the fan 701 is started cyclically to inflate the centrifugal compressor 4 and collect the gas through the gas collecting bottle 3. Then, by detecting the volume of the compressed gas in the gas collecting bottle 3, the sealing performance of the centrifugal compressor 4 can be tested during the working process of the centrifugal compressor 4. In this process, if the centrifugal compressor 4 has a large gas leakage, the total volume of gas collected in the gas collecting bottle 3 will be significantly reduced. Therefore, by detecting the reduced volume of gas in the gas collecting bottle 3, it can be determined whether the centrifugal compressor 4 has a serious leakage, thereby detecting its sealing performance. At the same time, by setting the fans 701 to start in an alternating cycle, when the fan 701 at one end is started, the fan 701 at the other end is in a stopped state, so that each fan 701 has time to cool down, avoiding the overheating problem caused by long-term continuous operation, thereby protecting the fan 701 motor and extending the service life of the equipment. In addition, since the gas pipes 5 at both ends alternately transport gas to the centrifugal compressor 4, this reciprocating motion ensures that the gas transmission process is continuous. Compared with the working mode of a single fan 701, the alternately started fan 701 can stop at one end while the other end continues to work, avoiding interruptions in the gas transmission process, thereby improving the overall gas transmission efficiency and enabling the centrifugal compressor 4 to obtain a continuous and stable gas supply.

[0034] The presence of the telescopic filter element 800 allows the device to reduce impurities by filtering the gas through the telescopic filter element 800 when extracting gas from the external environment, and the structure of the telescopic filter element 800 allows it to filter and ventilate only from one side. When the fan 701 on one side is in operation, only the telescopic filter element 800 on this side is in an extended state and its gas resistance is small, so that the wind generated by the fan 701 can pass through. On the other side, since the telescopic ring 801 is not in an extended state, the telescopic filter element 800 is in a contracted state at this time, and the gas resistance is greater than the gas resistance of the gas pipe 5. The gas in the air cavity 601 can only be discharged from the gas pipe 5, thereby avoiding leakage from the fan 701 side to affect the test results. In addition, this structure does not require additional drive structure and control structure. Not only is the structure itself simple, but it also realizes the function of a gas valve for gas filtration, simplifies the structure, and greatly reduces the cost of equipment use.

[0035] The temperature-sensing spring 903 in the structure automatically adjusts its length according to the change in the surface temperature of the collecting pipe 2, pushing the piston ring 904 to move. When the gas temperature rises, the temperature-sensing spring 903 extends, and the piston ring 904 enters the funnel-shaped cooling pipe 900, increasing the channel for cold air to flow into the air flow cavity 901 and enhancing the cooling effect. When the gas temperature decreases, the temperature-sensing spring 903 contracts and the piston ring 904 retreats, reducing the cold air flow channel and reducing the cooling intensity. This function realizes dynamic adjustment of the cooling intensity and improves the cooling efficiency. Traditional cooling equipment usually works at a fixed cooling intensity, which easily causes energy waste. The temperature-sensing spring 903 and the piston ring 904 are designed to enhance the cooling effect only when the gas temperature is high, and reduce the cooling intensity when the gas temperature is low, avoiding unnecessary cooling process, thereby saving energy. In addition, the temperature-sensing spring 903 can realize the start and stop of the cold air pipe 902 without an additional driving structure, further simplifying the system design and greatly reducing the system complexity and maintenance difficulty.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A test bench for testing the sealing performance of a centrifugal compressor, comprising an air filling pipe (1), an air collecting pipe (2) and an air collecting bottle (3), wherein a centrifugal compressor (4) to be tested is arranged between the air filling pipe (1) and the air collecting pipe (2), the air filling pipe (1) is connected to an air inlet pipe of the centrifugal compressor (4), and the air collecting pipe (2) is connected to an air outlet pipe of the centrifugal compressor (4), characterized in that: The inflation tube (1) is configured as a T-shaped tube, and the upper and lower ends of the inflation tube (1) are respectively fixedly connected to an air delivery tube (5), and the two air delivery tubes (5) are commonly connected to an inflation box (600), and the air delivery tubes (5) are respectively connected to two sides of opposite surfaces of the inflation box (600), and an air cavity (601) is provided inside the inflation box (600), and a push plate (602) is slidably provided inside the air cavity (601), and an inflation structure which is connected to the air cavity (601) and can only take in air in one direction is provided at both ends of the inflation box (600); the inflation structures at both ends cyclically inflate the air cavity (601) in turn, and the wind pressure generated by the inflation structure pushes the push plate (602) to move back and forth along the air cavity (601) and squeezes the gas in the air cavity (601) along the air delivery tube (5) and the inflation tube (1) into the centrifugal compressor (4); The inflatable structure comprises a fixed tube (700), a fan (701), and a telescopic filter element (800); the fixed tube (700) is fixedly arranged at both ends of the inflatable box (600) and communicates with the air cavity (601); the fan (701) is coaxially fixedly installed in the fixed tube (700); when the telescopic filter element (800) contracts, its filter element filtration resistance increases; when the telescopic filter element (800) extends, its filter element filtration resistance decreases; and the telescopic filter element (800) is fixedly installed in the inflatable box (600). 0) is coaxially fixedly connected to a flexible telescopic ring (801) around the fixed tube (700), the telescopic ring (801) is provided with an annular wind resistance chamber (802), the telescopic ring (801) is fixedly arranged in the fixed tube (700), and the wind resistance chamber (802) faces the air outlet direction of the fan (701), and when air is filled into the wind resistance chamber (802), the telescopic ring (801) and the telescopic filter element (800) are driven to extend along the fixed tube (700); A control valve (10) is also installed between the inflation pipe (1) and the gas delivery pipe (5); A cooling tube (900) is also coaxially sleeved on the air collecting tube (2); the diameter of the cooling tube (900) is larger than the diameter of the air collecting tube (2); an air flow cavity (901) is provided between the cooling tube (900) and the air collecting tube (2); the cooling tube (900) comprises an air inlet end and an air outlet end; the air inlet end is provided with a cold air tube (902) connected to the air flow cavity (901); the air outlet end is connected to the external environment; the air inlet end of the cooling tube (900) is in the shape of a funnel with a gradually increasing diameter; a temperature-sensitive spring (903) is provided in the air flow cavity (901) and its extension length can be changed with its own temperature change; the temperature-sensitive spring (903) is attached to the surface of the air collecting tube (2); the temperature-sensitive spring (903) is connected to the outside environment; One end of the spring (903) is fixedly arranged on the outer surface of the gas collecting pipe (2), and the other end of the temperature-sensitive spring (903) is provided with a piston ring (904) that can slide relative to the gas collecting pipe (2), and the expansion and contraction direction of the piston ring (904) is toward the funnel-shaped side of the cooling pipe (900), the major diameter of the piston ring (904) is equal to the inner diameter of the cooling pipe (900), and the minor diameter of the piston ring (904) is equal to the outer diameter of the gas collecting pipe (2); the initial position of the piston ring (904) is located on the non-funnel-shaped side of the cooling pipe (900), and when the temperature of the temperature-sensitive spring (903) rises due to heat, the piston ring (904) enters the funnel-shaped cooling pipe (900).

2. A test bench for testing the sealing performance of a centrifugal compressor according to claim 1, characterized in that: The temperature-sensitive spring (903) is made of a thermosensitive material or a shape memory alloy.

3. A test bench for testing the sealing performance of a centrifugal compressor according to claim 1, characterized in that: Limiting structures (603) attached to the surface of the air cavity (601) are also provided at both ends of the air cavity (601), a gap is left between the limiting structure (603) and the inflation structure, and the connection position between the air delivery pipe (5) and the air cavity (601) is arranged between the gaps.

4. A test bench for testing the sealing performance of a centrifugal compressor according to claim 1, characterized in that: The cold air pipe (902) injects constant pressure cooling gas into the air flow cavity (901).

5. The test bench for testing the sealing performance of a centrifugal compressor according to claim 1, characterized in that: The telescopic ring (801) is made of flexible material.

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