A centrifugal compressor anti-surge device

Abstract

The present invention provides a centrifugal compressor anti-surge device, which relates to the technical field of centrifugal compressors. It includes a shell, a speed sensing adjustment unit and a pressure sensing adjustment unit. A return air channel is provided inside the shell, and the two ends of the return air channel are respectively connected to the air intake and exhaust ports of the centrifugal compressor. The speed sensing adjustment unit is connected to the shell and is located on the air intake side, and the pressure sensing adjustment unit is connected to the shell and is located on the exhaust side. The device can dynamically adjust whether the return air channel is opened or closed according to the actual flow rate and pressure requirements, and can dynamically adjust the specific return air flow of the return air channel in the passage state; on this basis, it can dynamically adjust the high-pressure air return flow within an appropriate range, so that the centrifugal compressor can operate stably within the design operating range, protect the efficient and stable operation of the centrifugal compressor, improve the operating efficiency, and better meet the high stability requirements of customers.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal compressors, and in particular to an anti-surge device for centrifugal compressors. Background Art

[0002] Surge is a periodic airflow oscillation phenomenon that occurs in a centrifugal compressor when the intake flow rate is lower than the critical value. It usually manifests as violent pressure fluctuations and increased vibration of the machine body. In severe cases, it may cause equipment damage.

[0003] The specific reason for surge is that when the back pressure at the exhaust port of the centrifugal compressor is too high, the air intake of the compressor will drop below the critical value. At this time, the airflow will form a large vortex area on the back of the impeller, causing a sudden drop in the exhaust pressure. At this time, the pipeline pressure is higher than the compressor exhaust pressure, and the airflow flows back to the compressor, forming periodic oscillations. The exhaust pressure and flow rate pulsate periodically and greatly. The unit vibrates violently accompanied by low-frequency popping sounds. Bearings, seals and other components are easily damaged. The motor current fluctuates periodically, the feedback load is unstable, and the alternating stress causes abnormal wear of the impeller and bearings. In severe cases, the rotor and stator collide, causing serious damage to the components in a very short time. Therefore, the centrifugal compressor is not allowed to enter the surge zone under any conditions.

[0004] Generally speaking, during the design and development phase, centrifugal compressors rigorously research the customer's operating environment and operating range. This allows them to design a centrifugal compressor that achieves maximum efficiency near the operating point while retaining a sufficient safety margin. This ensures the compressor is both efficient and safe in actual use, effectively meeting the customer's needs. Typically, the compressor operates within the operating range, fully covering the customer's required operating range. However, in actual engineering environments, changes in the production environment often lead to significant changes to the customer's originally specified design operating range, inevitably causing the compressor to operate in the surge zone. In these cases, an anti-surge device must be added to ensure safe and stable operation of the compressor, preventing damage to the machine and losses to the customer.

[0005] For existing anti-surge devices, some choose to install rotor vibration sensors on centrifugal compressors. This is because the surge of centrifugal compressors is often accompanied by periodic vibration of the rotor. By detecting the rotor vibration, it is possible to clearly detect whether the centrifugal compressor is surging. In this way, a surge warning can be issued, thereby changing the compressor operating conditions to forcibly protect the compressor. This anti-surge method can indeed protect the safety of the machine very well, but frequent protective shutdowns caused by occasional changes in operating conditions may also cause production problems for customers, resulting in considerable losses.

[0006] Another part of the anti-surge device is selected based on the surge principle. Since the essential cause of surge is that the suction flow rate of the centrifugal compressor is lower than the critical value, the operating status of the centrifugal compressor can be accurately monitored. A pipe is used to connect the suction and exhaust ports of the centrifugal compressor. A solenoid valve is installed in the middle of the pipe to control the on-off of the air path. When the compressor is detected to be in a surge condition, the solenoid valve is opened to introduce a part of the compressor exhaust air flow into the compressor suction port, forcibly increasing the compressor suction flow rate, thereby avoiding compressor surge and forcibly expanding the compressor operating range. Even occasional large operating range changes will not exceed the compressor operating range, allowing the compressor to operate normally for a period of time, ensuring smooth production for customers. This anti-surge method has been actually tested on-site by customers and can effectively force the expansion of the centrifugal compressor operating range, avoiding the occasional triggering of centrifugal compressor protection measures that cause production stoppages. However, after the solenoid valve is connected, it is equivalent to connecting the compressor suction port and the compressor exhaust port through a pipe. Due to the changing working conditions, a large amount of high-pressure gas will enter the compressor suction port uncontrollably. At this time, although the compressor avoids surge, a large amount of ineffective work is done, and the compressor efficiency is very poor. Moreover, since the temperature of the compressor exhaust port is very high, the reliability of the solenoid valve will be greatly reduced if it is in a high temperature environment for a long time. Over time, it will malfunction and fail to work normally.

[0007] The applicant has discovered that there are at least the following technical problems in the prior art: due to the variable actual operating conditions at customer sites, it is difficult for centrifugal compressors to operate completely within the design operating range. If the existing anti-surge method is used, the centrifugal compressor will often shut down for protection, causing production interruptions for customers and resulting in large losses. Alternatively, the centrifugal compressor will have too low operating efficiency due to excessive reflux from the compressor exhaust port to the compressor intake port. The above methods cannot meet customer needs well, nor can they protect the stable and efficient operation of the compressor. Summary of the Invention

[0008] The present invention aims to provide a centrifugal compressor anti-surge device to solve the technical problems existing in the prior art. The various technical effects that can be produced by the preferred technical solution among the various technical solutions provided by the present invention are described in detail below.

[0009] To achieve the above objectives, the present invention provides the following technical solutions:

[0010] A centrifugal compressor anti-surge device includes a shell, a speed sensing adjustment unit and a pressure sensing adjustment unit. A return air channel is provided inside the shell, and the two ends of the return air channel are respectively connected to the suction port and the exhaust port of the centrifugal compressor. The speed sensing adjustment unit is connected to the shell and is located on the suction port side, and the pressure sensing adjustment unit is connected to the shell and is located on the exhaust port side. The speed sensing adjustment unit can sense the flow velocity change at the suction port and thus control the on-off of the return air channel and the return air flow rate in the passage state. The pressure sensing adjustment unit can sense the pressure change at the exhaust port and thus control the on-off of the return air channel and the return air flow rate in the passage state.

[0011] Preferably, the pressure sensing adjustment unit includes a pressure sensing piston and a pressure sensing spring, one end of the pressure sensing piston is provided with a first air vent and the other end thereof is connected to one end of the pressure sensing spring, the other end of the pressure sensing spring is connected to the shell, the pressure change at the exhaust port can drive the pressure sensing piston to move relative to the return air channel, when the first air vent moves to the corresponding position of the return air channel, the return air channels on both sides of the pressure sensing piston can be connected through the first air vent.

[0012] Preferably, a first movable groove is provided inside the shell, the first movable groove is connected to the return air channel, the pressure sensing piston moves relatively inside the first movable groove, the end of the pressure sensing piston away from the pressure sensing spring is in contact with one end of the first movable groove, the end of the pressure sensing spring away from the pressure sensing piston is connected to the other end of the first movable groove, and the length direction of the first movable groove is perpendicular to the length direction of the return air channel, so that the moving direction of the pressure sensing piston is perpendicular to the flow direction of the return air inside the return air channel.

[0013] Preferably, the diameter of the first vent gradually decreases from the end away from the pressure sensing spring to the end close to the pressure sensing spring.

[0014] Preferably, the speed sensing adjustment unit includes a speed sensing piston, a speed sensing spring and a speed sensing trigger assembly, one end of the speed sensing piston is provided with a second air vent and the other end thereof is connected to one end of the speed sensing spring, the other end of the speed sensing spring is connected to the shell, one end of the speed sensing trigger assembly is located at the air intake port and the other end thereof is in active contact with the speed sensing piston, the pressure change at the air intake port can drive the speed sensing trigger assembly to move, the speed sensing trigger assembly can drive the speed sensing piston to move relative to the return air channel, and when the second air vent moves to the corresponding position of the return air channel, the return air channels on both sides of the speed sensing piston can be connected through the second air vent.

[0015] Preferably, the speed sensing trigger assembly includes a speed sensing rod, a speed sensing trigger connecting rod and a speed sensing trigger spring, the speed sensing rod is located at the air intake, the speed sensing rod is in movably contact with one end of the speed sensing trigger connecting rod, the other end of the speed sensing trigger connecting rod is connected to one end of the speed sensing trigger spring, and the other end of the speed sensing trigger spring is connected to the shell, the speed sensing trigger connecting rod is provided with a first moving trigger part at a corresponding position of the speed sensing piston, and the speed sensing piston is provided with a second moving trigger part at a corresponding position of the speed sensing trigger connecting rod, and the speed sensing trigger connecting rod can form an extrusion contact with the second moving trigger part through the first moving trigger part during the relative movement, so as to drive the speed sensing piston to move relative to each other.

[0016] Preferably, a second movable groove is provided inside the shell, the second movable groove is connected to the return gas channel, the speed sensing piston moves relatively inside the second movable groove, the end of the speed sensing spring away from the speed sensing piston is connected to the second movable groove, and the length direction of the second movable groove is perpendicular to the length direction of the return gas channel, so that the moving direction of the speed sensing piston is perpendicular to the flow direction of the return gas inside the return gas channel.

[0017] Preferably, a third movable groove is provided inside the shell, the third movable groove is connected to the second movable groove, one end of the speed sensing trigger link moves relatively inside the third movable groove, the end of the speed sensing trigger spring away from the speed sensing trigger link is connected to the third movable groove, and the length direction of the third movable groove is parallel to the length direction of the return air channel.

[0018] Preferably, the speed sensing rod includes a connecting rod, a force-bearing rod and a triggering rod. The connecting rod, the force-bearing rod and the triggering rod are all connected together at one end. The other end of the connecting rod is rotatably connected to the pipe wall corresponding to the air intake. The other end of the force-bearing rod extends to the center of the air intake, and the other end of the triggering rod is in active contact with the speed sensing trigger connecting rod.

[0019] Preferably, the diameter of the second vent gradually decreases from the end away from the speed sensing spring to the end close to the speed sensing spring.

[0020] The beneficial effects of the present invention are as follows: by providing a speed sensing adjustment unit and a pressure sensing adjustment unit, the speed sensing adjustment unit can sense the flow velocity change at the air inlet and thereby control the on-off of the return air channel and the return air flow rate in the passage state; the pressure sensing adjustment unit can sense the pressure change at the air outlet and thereby control the on-off of the return air channel and the return air flow rate in the passage state;

[0021] Under the mutual cooperation of the speed sensing adjustment unit and the pressure sensing adjustment unit, it is possible to dynamically adjust whether the return gas channel is opened or closed according to the actual flow rate and pressure requirements, and it is possible to dynamically adjust the specific return gas flow rate of the return gas channel in the passage state;

[0022] On this basis, the high-pressure gas return flow rate can be dynamically adjusted within an appropriate range, allowing the centrifugal compressor to operate stably within the designed operating conditions, avoiding protective shutdowns that cause large losses to customers' production interruptions, protecting the efficient and stable operation of the centrifugal compressor, improving operating efficiency, and better meeting customers' high stability needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 or the description of the prior art. 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.

[0024] Figure 1 It is a cross-sectional structural diagram of the anti-surge device for a centrifugal compressor of the present invention;

[0025] Figure 2 It is a partial structural diagram of the anti-surge device for a centrifugal compressor of the present invention;

[0026] Figure 3 This is a diagram showing the operating range of the centrifugal compressor anti-surge device of the present invention;

[0027] In the figure, 1 is a housing; 11 is a return air channel; 12 is a first movable tank; 13 is a second movable tank; 14 is a third movable tank;

[0028] 2. Speed-sensing adjustment unit; 21. Speed-sensing piston; 211. Second vent; 212. Second movable trigger unit; 22. Speed-sensing spring; 23. Speed-sensing trigger assembly; 231. Speed-sensing rod; 2311. Connecting rod; 2312. Force-bearing rod; 2313. Trigger rod; 232. Speed-sensing trigger connecting rod; 2321. First movable trigger unit; 233. Speed-sensing trigger spring;

[0029] 3. Pressure sensing adjustment unit; 31. Pressure sensing piston; 311. First vent; 32. Pressure sensing spring;

[0030] 4. Inhalation port;

[0031] 5. Exhaust port;

[0032] 61. Working area; 62. Surge area; 63. Expanded working area;

[0033] 71. Speed ​​opening line; 72. Pressure opening line; 73. Design surge line; 74. Design surge warning line; 75. Blockage line; 76. Blockage warning line; 77. Speed ​​line. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "lateral", "length", "width", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "side" and the like indicate positions or location relationships based on the attached Figure 1 The orientation or positional relationship shown is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0036] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention depending on the specific circumstances.

[0037] Reference Figures 1 to 3 , the present invention provides a centrifugal compressor anti-surge device, comprising a housing 1, a speed sensing and regulating unit 2 and a pressure sensing and regulating unit 3;

[0038] The housing 1 is provided with a return air passage 11, and both ends of the return air passage 11 are respectively connected to the air intake 4 and the air discharge 5 of the centrifugal compressor;

[0039] The speed sensing and regulating unit 2 is connected to the housing 1 and is located on the side of the air inlet 4. The pressure sensing and regulating unit 3 is connected to the housing 1 and is located on the side of the air outlet 5.

[0040] The speed sensing and regulating unit 2 can sense the flow velocity changes at the air intake port 4 and thereby control the on-off of the return air channel 11 and the return air volume in the passage state. The pressure sensing and regulating unit 3 can sense the pressure changes at the air exhaust port 5 and thereby control the on-off of the return air channel 11 and the return air volume in the passage state.

[0041] Under the mutual cooperation of the speed sensing adjustment unit 2 and the pressure sensing adjustment unit 3, it is possible to dynamically adjust whether the return gas channel 11 is opened or closed according to the actual flow rate and pressure requirements, and it is possible to dynamically adjust the specific return gas flow rate of the return gas channel 11 in the passage state;

[0042] On this basis, the high-pressure gas return flow rate can be dynamically adjusted within an appropriate range, allowing the centrifugal compressor to operate stably within the designed operating conditions, avoiding protective shutdowns that cause large losses to customers' production interruptions, protecting the efficient and stable operation of the centrifugal compressor, improving operating efficiency, and better meeting customers' high stability needs.

[0043] The anti-surge device of the centrifugal compressor is preferably composed of fully mechanized components, so that it is not afraid of harsh environments such as high temperature and high pressure.

[0044] As an optional embodiment, the pressure sensing adjustment unit 3 includes a pressure sensing piston 31 and a pressure sensing spring 32. One end of the pressure sensing piston 31 is provided with a first vent 311 and the other end thereof is connected to one end of the pressure sensing spring 32. The other end of the pressure sensing spring 32 is connected to the housing 1.

[0045] The exhaust port 5 is connected to the space where the pressure sensing piston 31 is located. Therefore, the pressure change at the exhaust port 5 can drive the pressure sensing piston 31 to move relative to the return gas channel 11, squeezing and driving the pressure sensing piston 31 as shown in the figure. Figure 2 As shown, when the first vent 311 moves to the corresponding position of the return air channel 11, the return air channels 11 on both sides of the pressure sensing piston 31 can be connected through the first vent 311. At this time, the return air channels 11 are connected at the pressure sensing regulating unit 3.

[0046] It is worth noting that the diameter of the first vent 311 gradually decreases from the end away from the pressure sensing spring 32 to the end close to the pressure sensing spring 32. Figure 1 As shown in the process of moving to the right, the first vent 311 can gradually increase the flow rate of the return air. By optimizing the design of the diameter of the first vent 311, dynamic adjustment can be further achieved.

[0047] In order to arrange the pressure sensing piston 31 and the pressure sensing spring 32 more reasonably, a first movable groove 12 is preferably provided inside the housing 1 , and the first movable groove 12 is connected to the return air channel 11 ;

[0048] The pressure sensing piston 31 moves relatively inside the first movable groove body 12, and the end of the pressure sensing piston 31 away from the pressure sensing spring 32 contacts one end of the first movable groove body 12, and the end of the pressure sensing spring 32 away from the pressure sensing piston 31 is connected to the other end of the first movable groove body 12. The length direction of the first movable groove body 12 is perpendicular to the length direction of the return gas channel 11, so that the moving direction of the pressure sensing piston 31 is perpendicular to the flow direction of the return gas inside the return gas channel 11.

[0049] As an optional embodiment, the speed sensing adjustment unit 2 includes a speed sensing piston 21, a speed sensing spring 22 and a speed sensing trigger assembly 23;

[0050] One end of the speed sensing piston 21 is provided with a second vent 211 and the other end thereof is connected to one end of a speed sensing spring 22 , and the other end of the speed sensing spring 22 is connected to the housing 1 ;

[0051] One end of the speed sensing trigger assembly 23 is located at the air intake port 4, and the other end thereof is in active contact with the speed sensing piston 21. Pressure changes at the air intake port 4 can drive the speed sensing trigger assembly 23 to move, and the speed sensing trigger assembly 23 can drive the speed sensing piston 21 to move relative to the return air channel 11. When the second air vent 211 moves to a corresponding position of the return air channel 11, the return air channels 11 on both sides of the speed sensing piston 21 can be connected through the second air vent 211. At this time, the return air channel 11 is connected to the speed sensing adjustment unit 2.

[0052] It is worth noting that the diameter of the second vent 211 gradually decreases from the end away from the speed sensing spring 22 to the end close to the speed sensing spring 22. Figure 1 As shown in the process of moving to the right, the second vent 211 can gradually increase the flow rate of the return air. By optimizing the design of the diameter of the second vent 211, dynamic adjustment can be further achieved.

[0053] As an optional embodiment, the speed sensing trigger assembly 23 includes a speed sensing rod 231, a speed sensing trigger link 232 and a speed sensing trigger spring 233;

[0054] The speed sensing rod 231 is located at the air inlet 4. The speed sensing rod 231 is in movable contact with one end of the speed sensing trigger link 232. The other end of the speed sensing trigger link 232 is connected to one end of the speed sensing trigger spring 233. The other end of the speed sensing trigger spring 233 is connected to the housing 1.

[0055] Furthermore, the speed-sensing trigger link 232 is provided with a first movement trigger portion 2321 at a position corresponding to the speed-sensing piston 21, and the speed-sensing piston 21 is provided with a second movement trigger portion 212 at a position corresponding to the speed-sensing trigger link 232. During the relative movement, the speed-sensing trigger link 232 can form a pressing contact with the second movement trigger portion 212 through the first movement trigger portion 2321, thereby driving the speed-sensing piston 21 to move relative to each other.

[0056] Here, the first movement trigger part 2321 can preferably be a structure of an extruded contact block, and the second movement trigger part 212 can preferably be a tilted contact surface. Through the tilted setting, the relative movement of the speed sensing trigger link 232 in the up and down directions can be converted into the relative movement of the speed sensing piston 21 in the left and right directions.

[0057] As an optional embodiment, a second movable groove 13 is provided inside the shell 1, and the second movable groove 13 is connected to the return gas channel 11. The speed sensing piston 21 moves relatively inside the second movable groove 13, and the speed sensing spring 22 is connected to the second movable groove 13 at one end away from the speed sensing piston 21. The length direction of the second movable groove 13 is perpendicular to the length direction of the return gas channel 11, so that the moving direction of the speed sensing piston 21 is perpendicular to the flow direction of the return gas inside the return gas channel 11.

[0058] As an optional embodiment, a third movable slot 14 is provided inside the shell 1, and the third movable slot 14 is connected to the second movable slot 13. One end of the speed sensing trigger link 232 moves relatively inside the third movable slot 14, and the speed sensing trigger spring 233 is connected to the third movable slot 14 at one end away from the speed sensing trigger link 232. The length direction of the third movable slot 14 is parallel to the length direction of the return air channel 11.

[0059] As an optional embodiment, the speed sensing rod 231 includes a connecting rod 2311, a force-bearing rod 2312 and a triggering rod 2313;

[0060] The connecting rod 2311, the force-bearing rod 2312 and the triggering rod 2313 are all connected together at one end;

[0061] The other end of the connecting rod 2311 is rotatably connected to the pipe wall corresponding to the air inlet 4, so that the speed sensing rod 231 as a whole can rotate relative to the connection;

[0062] The other end of the force-bearing branch rod 2312 extends to the center of the air inlet 4, so that the force-bearing branch rod 2312 can fully contact the airflow at the air inlet 4, and the airflow can push the force-bearing branch rod 2312 to rotate relatively;

[0063] The other end of the trigger rod 2313 is in active contact with the bottom end of the speed sensing trigger link 232. When the speed sensing rod 231 rotates, the trigger rod 2313 applies actual force to the speed sensing trigger link 232.

[0064] When the flow rate is high, the speed sensing rod 231 can rotate counterclockwise, and the trigger rod 2313 exerts an upward force on the speed sensing trigger connecting rod 232, raising the height of the speed sensing trigger connecting rod 232, causing the speed sensing piston 21 to move leftward;

[0065] When the flow rate is low, the speed sensing rod 231 can rotate clockwise by gravity, and the triggering rod 2313 no longer applies an upward force to the speed sensing triggering connecting rod 232, thereby reducing the height of the speed sensing triggering connecting rod 232 and causing the speed sensing piston 21 to move rightward.

[0066] Reference Figure 3 , is the operating range diagram of the centrifugal compressor after the anti-surge device mentioned in the present invention is applied. In the figure, the two coordinate axes are V, which is the flow velocity at the suction port 4, and the unit is m 3 / min, P is the pressure at the exhaust port 5, the unit is kPa.

[0067] The speed opening line 71 in the figure is a speed value designed according to demand. When the flow rate of the air intake port 4 is higher than the design value, the speed sensing piston 21 can close the return air channel 11 with the cooperation of the speed sensing spring 22. When the flow rate of the air intake port 4 is lower than the design value, the speed sensing trigger connecting rod 232 can drive the speed sensing piston 21 to open the return air channel 11, and can dynamically adjust the opening degree according to the flow rate, so as to control the return air volume and avoid too much return air volume, which causes the compressor efficiency to be too low.

[0068] The pressure opening line 72 in the figure is a pressure value designed according to demand. When the pressure at the exhaust port 5 is higher than the designed value, the pressure sensing piston 31 can open the return gas channel 11. When the pressure at the exhaust port 5 is lower than the designed value, the pressure sensing piston 31 can close the return gas channel 11 with the cooperation of the pressure sensing spring 32. The opening degree can be dynamically adjusted according to the pressure level, thereby controlling the return gas flow rate and avoiding excessive return gas flow, which may cause low compressor efficiency.

[0069] The design surge line 73 in the figure represents that the centrifugal compressor, which should be operating normally within the working area 61, will experience severe periodic oscillations if it crosses the design surge line 73 and enters the left side of the design surge line 73, which may cause damage to the centrifugal compressor.

[0070] The design surge warning line 74 in the figure represents a warning before entering the left side of the design surge line 73. When crossing the design surge warning line 74, the device will alarm, indicating that it may enter the surge zone 62.

[0071] The blockage line 75 in the figure represents that when crossing the blockage line 75 and entering the right side of the blockage line 75, the suction capacity of the centrifugal compressor has reached the upper limit, which will cause blockage;

[0072] The blockage warning line 76 in the figure represents a warning before entering the right side of the blockage line 75. When crossing the blockage warning line 76, the device will alarm to indicate that it may enter the blockage line 75.

[0073] The speed lines 77 in the figure are multiple lines that are first designed and then obtained through testing. The speed lines 77 clarify the performance of the centrifugal compressor and can help obtain the range of the working area 61.

[0074] When the centrifugal compressor operates normally in the working area 61 (in the adjacent Figure 3 (indicated by the shaded portion in the figure), either the flow rate at the centrifugal compressor suction port 4 is higher than the design value (to the right of the speed opening line 71), and the speed sensing piston 21 is in the closed state, or the pressure at the centrifugal compressor exhaust port 5 is lower than the design value (below the pressure opening line 72), and the pressure sensing piston 31 is in the closed state. In this case, the reflux gas channel cannot be formed, and the centrifugal compressor can operate normally and efficiently according to the actual working conditions;

[0075] It is worth noting that although there is a certain area in the working zone 61 to the left of the speed opening line 71 and above the pressure opening line 72, the area is relatively small and has a very small application range in actual applications. In this embodiment, this area is not given much attention.

[0076] When there is a significant change in the working conditions at the customer's site, the centrifugal compressor must enter the surge zone 62 for operation. At this time, the flow rate of the centrifugal compressor suction port 4 is lower than the design value. According to the speed, the speed sensing piston 21 will move a certain distance, so that the second vent 211 is connected to a certain extent. At the same time, according to the pressure of the centrifugal compressor exhaust port 5, the pressure sensing piston 31 will also move a certain distance, so that the first vent 311 is connected to a certain extent. At this time, the high-pressure gas return channel is opened to a certain size. Under proper design, the required return gas flow rate will only be slightly greater than the requirement of no surge under the current working conditions. While avoiding surge of the centrifugal compressor, there is no need to secondary compress too much return gas, thereby ensuring the efficiency of the compressor. Moreover, under the above operation, the range of the working area 61 is actually expanded to form an expanded working area 63. The expanded working area 63 is because the high-pressure return air supply is opened to forcibly expand the centrifugal compressor's operating working area, which has a certain stability and a certain degree of efficiency.

[0077] The working principle of the anti-surge device mentioned in the present invention is:

[0078] When the centrifugal compressor is working normally Figure 3 When inside the working area 61 shown;

[0079] In the high flow rate and high pressure area, the pressure drives the pressure sensing piston 31 to move rightward, and the high-pressure gas can pass through the pressure sensing piston 31. However, due to the high flow rate, the speed sensing rod 231 rotates counterclockwise, raising the speed sensing trigger connecting rod 232, causing the speed sensing piston 21 to move leftward, resulting in the speed sensing piston 21 being blocked from air flow, so there will be no backflow to replenish gas to prevent surge.

[0080] In the high flow rate and low pressure area, due to the low pressure, the pressure sensing spring 32 drives the pressure sensing piston 31 to move leftward, and the high-pressure gas cannot pass through the pressure sensing piston 31. In addition, due to the high flow rate, the speed sensing rod 231 rotates counterclockwise, raising the speed sensing trigger connecting rod 232, causing the speed sensing piston 21 to move leftward, resulting in the speed sensing piston 21 also not being ventilated, so there will be no backflow to replenish gas to prevent surge;

[0081] In the low flow rate and high pressure area, the pressure drives the pressure sensing piston 31 to move rightward, and the high-pressure gas can pass through the pressure sensing piston 31. However, since the flow rate is still relatively high, the speed sensing rod 231 in this area will still rotate counterclockwise, raising the speed sensing trigger connecting rod 232, causing the speed sensing piston 21 to move leftward, resulting in the speed sensing piston 21 being blocked from air flow, so there will be no backflow to replenish gas to prevent surge.

[0082] In the low flow rate and low pressure area, the pressure sensing spring 32 drives the pressure sensing piston 31 to move leftward, and the high-pressure gas cannot pass through the pressure sensing piston 31. At this time, although the flow rate is low, the speed sensing rod 231 can rotate clockwise to reduce the height of the speed sensing trigger connecting rod 232, causing the speed sensing piston 21 to move rightward. At this time, the speed sensing piston 21 can be ventilated, but the overall gas still cannot pass through, so there will be no backflow to replenish gas and prevent surge.

[0083] Only when the operating point of the centrifugal compressor crosses the originally designed working area 61 and enters the newly designed expanded working area 63, the operating point is located to the left of the speed opening line 71 and above the pressure opening line 72. At this time, the high pressure drives the pressure sensing piston 31 to move right, and the speed sensing rod 231 can rotate clockwise, reducing the height of the speed sensing trigger connecting rod 232, so that the speed sensing piston 21 moves to the right. At this time, the high-pressure gas at the exhaust port 5 can pass through the pressure sensing piston 31 and the speed sensing piston 21 in turn to enter the compressor intake port 4, forming a backflow to replenish air to prevent surge and ensure that the compressor still operates smoothly.

[0084] Moreover, when the exhaust pressure is higher and the intake speed is lower, surge is more likely. At this time, the more the pressure sensing piston 31 and the speed sensing piston 21 move to the right, the larger the reflux area is, which leads to more reflux air supply, and surge can still be avoided. At the same time, due to the reasonable design of the piston curve, the reflux air supply volume is sufficient, and the efficiency of the centrifugal compressor can be kept from being too low.

[0085] It is also possible to carry out more refined structural design of the various components of the speed sensing adjustment unit 2 and the pressure sensing adjustment unit 3, and highly customize the adjustment of the return air volume. The position and size of the expanded working area 63 can be flexibly adjusted according to the customer's actual working conditions, thereby perfectly adapting to the customer's needs, ensuring the operating stability of the compressor, and having a larger operating range.

[0086] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A centrifugal compressor anti-surge device, characterized in that: The invention comprises a shell (1), a speed sensing regulating unit (2) and a pressure sensing regulating unit (3), wherein a return air channel (11) is provided inside the shell (1), and the two ends of the return air channel (11) are respectively connected to the air inlet (4) and the air outlet (5) of the centrifugal compressor, the speed sensing regulating unit (2) is connected to the shell (1) and is located on one side of the air inlet (4), and the pressure sensing regulating unit (3) is connected to the shell (1) and is located on one side of the air outlet (5), the speed sensing regulating unit (2) can sense the flow velocity change at the air inlet (4) and thus control the on-off of the return air channel (11) and the return air flow rate in the passage state, and the pressure sensing regulating unit (3) can sense the pressure change at the air outlet (5) and thus control the on-off of the return air channel (11) and the return air flow rate in the passage state; The pressure sensing regulating unit (3) comprises a pressure sensing piston (31) and a pressure sensing spring (32); one end of the pressure sensing piston (31) is provided with a first vent (311) and the other end thereof is connected to one end of the pressure sensing spring (32); the other end of the pressure sensing spring (32) is connected to the housing (1); The speed sensing regulating unit (2) comprises a speed sensing piston (21), a speed sensing spring (22) and a speed sensing trigger assembly (23); one end of the speed sensing piston (21) is provided with a second vent (211) and the other end thereof is connected to one end of the speed sensing spring (22); the other end of the speed sensing spring (22) is connected to the housing (1); one end of the speed sensing trigger assembly (23) is located at the air intake (4) and the other end thereof is in active contact with the speed sensing piston (21).

2. The centrifugal compressor anti-surge device according to claim 1, characterized in that: The pressure change at the exhaust port (5) can drive the pressure sensing piston (31) to move relative to the return air channel (11). When the first vent (311) moves to a corresponding position of the return air channel (11), the return air channels (11) on both sides of the pressure sensing piston (31) can be connected through the first vent (311).

3. The centrifugal compressor anti-surge device according to claim 2, characterized in that: A first movable groove (12) is provided inside the shell (1), and the first movable groove (12) is connected to the return gas channel (11). The pressure sensing piston (31) moves relatively inside the first movable groove (12). One end of the pressure sensing piston (31) away from the pressure sensing spring (32) contacts one end of the first movable groove (12), and one end of the pressure sensing spring (32) away from the pressure sensing piston (31) is connected to the other end of the first movable groove (12). The length direction of the first movable groove (12) and the length direction of the return gas channel (11) are perpendicular to each other, so that the moving direction of the pressure sensing piston (31) and the flow direction of the return gas inside the return gas channel (11) are perpendicular to each other.

4. The centrifugal compressor anti-surge device according to claim 2, characterized in that: The diameter of the first vent (311) gradually decreases from an end away from the pressure sensing spring (32) to an end close to the pressure sensing spring (32).

5. The centrifugal compressor anti-surge device according to claim 1, characterized in that: The pressure change at the air intake port (4) can drive the speed sensing trigger component (23) to move, and the speed sensing trigger component (23) can drive the speed sensing piston (21) to move relative to the return air channel (11). When the second air vent (211) moves to a corresponding position of the return air channel (11), the return air channels (11) on both sides of the speed sensing piston (21) can be connected through the second air vent (211).

6. The centrifugal compressor anti-surge device according to claim 5, characterized in that: The speed sensing trigger assembly (23) includes a speed sensing rod (231), a speed sensing trigger connecting rod (232) and a speed sensing trigger spring (233), wherein the speed sensing rod (231) is located at the air inlet (4), the speed sensing rod (231) is in movable contact with one end of the speed sensing trigger connecting rod (232), the other end of the speed sensing trigger connecting rod (232) is connected to one end of the speed sensing trigger spring (233), and the other end of the speed sensing trigger spring (233) is connected to the housing (1). Then, the speed sensing trigger connecting rod (232) is provided with a first moving trigger portion (2321) at a corresponding position of the speed sensing piston (21), and the speed sensing piston (21) is provided with a second moving trigger portion (212) at a corresponding position of the speed sensing trigger connecting rod (232). During the relative movement, the speed sensing trigger connecting rod (232) can form a pressing contact with the second moving trigger portion (212) through the first moving trigger portion (2321), thereby driving the speed sensing piston (21) to move relatively.

7. The centrifugal compressor anti-surge device according to claim 6, characterized in that: A second movable groove (13) is provided inside the housing (1), the second movable groove (13) is connected to the return gas channel (11), the speed sensing piston (21) moves relatively inside the second movable groove (13), the end of the speed sensing spring (22) away from the speed sensing piston (21) is connected to the second movable groove (13), and the length direction of the second movable groove (13) is perpendicular to the length direction of the return gas channel (11), so that the moving direction of the speed sensing piston (21) and the flow direction of the return gas inside the return gas channel (11) are perpendicular to each other.

8. The centrifugal compressor anti-surge device according to claim 7, characterized in that: A third movable slot (14) is provided inside the shell (1), and the third movable slot (14) is connected to the second movable slot (13). One end of the speed-sensing trigger link (232) moves relatively inside the third movable slot (14), and one end of the speed-sensing trigger spring (233) away from the speed-sensing trigger link (232) is connected to the third movable slot (14). The length direction of the third movable slot (14) is parallel to the length direction of the return air channel (11).

9. The centrifugal compressor anti-surge device according to claim 6, characterized in that: The speed sensing rod (231) comprises a connecting rod (2311), a force-bearing rod (2312) and a triggering rod (2313); the connecting rod (2311), the force-bearing rod (2312) and the triggering rod (2313) are all connected together at one end; the other end of the connecting rod (2311) is rotatably connected to the pipe wall corresponding to the air intake (4); the other end of the force-bearing rod (2312) extends to the center of the air intake (4); and the other end of the triggering rod (2313) is in active contact with the speed sensing triggering connecting rod (232).

10. The centrifugal compressor anti-surge device according to claim 5, characterized in that: The diameter of the second vent (211) gradually decreases from an end away from the speed sensing spring (22) to an end close to the speed sensing spring (22).

Images