Anti-surge device of centrifugal compressor

Abstract

The invention provides an anti-surge device of a centrifugal compressor, and relates to the technical field of centrifugal compressors. The device comprises a shell, a speed sensing and adjusting unit and a pressure sensing and adjusting unit, a backflow air channel is formed in the shell, the two ends of the backflow air channel are communicated with an air suction port and an exhaust port of the centrifugal compressor respectively, and the speed sensing and adjusting unit is connected with the shell and located on one side of the air suction port. The pressure induction adjusting unit is connected with the shell and located on one side of the exhaust port. The device can dynamically adjust whether the backflow air channel is opened or closed according to the actual flow speed and pressure requirements, and can dynamically adjust the specific backflow air flow of the backflow air channel in the access state. On the basis, the backflow amount of the high-pressure air can be dynamically adjusted within a proper range, so that the centrifugal compressor can stably operate within a designed working condition range, efficient and stable operation of the centrifugal compressor is protected, the operation efficiency is improved, and the high-stability requirement of customers is better met.

Description

Technical Field

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

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

[0003] The specific reason for the occurrence of surge is that when the back pressure at the exhaust port of the centrifugal compressor is too high, the intake air volume of the compressor will drop below the critical value. At this time, a large-area eddy current area will be formed on the back of the impeller, resulting in a sudden drop in the exhaust port pressure. At this time, the pipeline pressure is higher than the exhaust port pressure of the compressor, and the air flow will flow back to the compressor, forming a periodic oscillation. The exhaust port pressure and flow rate will pulsate greatly in a cycle, the unit will vibrate violently with low-frequency popping sounds, components such as bearings and seals are easily damaged, the motor current will fluctuate periodically, the feedback load is unstable, and the alternating dynamic stress will cause abnormal wear of the impeller and bearings. In severe cases, it will cause a collision between the rotor and the stator, causing serious damage to the components in a very short time. Therefore, it is not allowed for the centrifugal compressor to enter the surge zone to work under any conditions.

[0004] Generally speaking, during the design and development stage of a centrifugal compressor, the customer's usage environment and operating condition range will be strictly investigated to design a centrifugal compressor with the highest efficiency near the operating point while retaining sufficient safety margins for the customer, so as to ensure that the compressor is efficient and safe during actual use by the customer, thus well meeting the customer's needs. Usually, the compressor will operate in the working area, and the working area completely covers the operating condition range required by the customer. However, in the actual engineering environment, due to changes in the production environment, the originally required design condition range of the customer often changes greatly, which inevitably leads to the possibility that the compressor may enter the surge zone to work. At this time, an anti-surge device must be added to protect the safe and stable operation of the compressor and avoid losses caused by machine damage to the customer.

[0005] For existing anti-surge devices, some choose to install a rotor vibration sensor on the centrifugal compressor. Because the surge of a centrifugal compressor is often accompanied by the periodic vibration of the rotor, whether the centrifugal compressor surges can be clearly detected by detecting the rotor vibration. In this way, a surge warning can be issued, and then the compressor operating condition can be changed to forcibly protect the compressor. This anti-surge method can indeed well protect the safety of the machine, but the frequent protective shutdowns caused by occasional condition changes may also cause production troubles for the customer and bring no small losses.

[0006] Another part of the surge prevention device starts from the surge principle. Since the essential cause of surge is that the inlet flow rate of the centrifugal compressor is lower than the critical value, it is possible to accurately monitor the operating state of the centrifugal compressor, connect the inlet and outlet of the centrifugal compressor with a pipeline, and install a solenoid valve in the middle of the pipeline to control the on-off of the gas path. When it is detected that the compressor is in the surge condition, the solenoid valve is opened, and a part of the compressor exhaust gas flow is introduced into the compressor inlet to forcibly increase the inlet flow rate of the compressor, thereby avoiding compressor surge, forcibly expanding the compressor operating range, so that even occasional large operating range changes will not exceed the compressor operating range, and thus the compressor can also operate normally for a period of time to ensure the smooth progress of the customer's production. This surge prevention method has been actually tested at the customer's site and can effectively and forcibly broaden the operating range of the centrifugal compressor, avoiding the problem of production shutdown caused by occasional triggering of the centrifugal compressor protection measures. However, after the solenoid valve is connected, it is equivalent to connecting the compressor inlet and the compressor outlet through a pipeline. Due to the changing working conditions, a large amount of high-pressure gas will enter the compressor inlet uncontrollably. At this time, although the compressor avoids surge, it does a lot of useless work and the compressor efficiency is very poor; moreover, since the temperature of the compressor outlet is very high, the reliability of the solenoid valve will be greatly reduced when it is in a high-temperature environment for a long time, and it will malfunction and cannot work properly after a long time.

[0007] The applicant of the present invention has found that there are at least the following technical problems in the prior art: Due to the changing working conditions in the actual use environment at the customer's site, it is very difficult for the centrifugal compressor to operate completely within the designed working range. If the existing surge prevention method is adopted, the centrifugal compressor will often stop protectively, causing interruption of the customer's production and resulting in great losses, or the centrifugal compressor will have too low operating efficiency due to too large a return gas volume from the compressor outlet to the compressor inlet. The above methods cannot well meet the customer's needs and cannot protect the stable and efficient operation of the compressor. Summary of the Invention

[0008] The purpose of the present invention is to provide a surge prevention device for a centrifugal compressor to solve the technical problems existing in the prior art. The preferred technical solutions provided by the present invention can produce many technical effects as described below.

[0009] To achieve the above object, the present invention provides the following technical solutions: A surge prevention device for a centrifugal compressor, comprising a housing, a speed induction adjustment unit and a pressure induction adjustment unit. A return air channel is arranged inside the housing. Both ends of the return air channel are respectively communicated with the suction port and the discharge port of the centrifugal compressor. The speed induction adjustment unit is connected to the housing and is located on one side of the suction port. The pressure induction adjustment unit is connected to the housing and is located on one side of the discharge port. The speed induction adjustment unit can sense the flow velocity change at the suction port and then control the on-off of the return air channel and the return air flow rate in the passage state. The pressure induction adjustment unit can sense the pressure change at the discharge port and then control the on-off of the return air channel and the return air flow rate in the passage state.

[0010] Preferably, the pressure induction adjustment unit includes a pressure induction piston and a pressure induction spring. One end of the pressure induction piston is provided with a first ventilation port and the other end thereof is connected to one end of the pressure induction spring. The other end of the pressure induction spring is connected to the housing. The pressure change at the discharge port can drive the pressure induction piston to move relative to the return air channel. When the first ventilation port moves to the corresponding position of the return air channel, the return air channels on both sides of the pressure induction piston can be communicated through the first ventilation port.

[0011] Preferably, a first moving groove body is opened inside the housing. The first moving groove body is communicated with the return air channel. The pressure induction piston moves relatively inside the first moving groove body. One end of the pressure induction piston away from the pressure induction spring contacts one end of the first moving groove body. The other end of the pressure induction spring away from the pressure induction piston is connected to the other end of the first moving groove body. The length direction of the first moving groove body is perpendicular to the length direction of the return air channel, so that the moving direction of the pressure induction piston is perpendicular to the flowing direction of the return air inside the return air channel.

[0012] Preferably, the diameter of the first ventilation port gradually decreases from the end away from the pressure induction spring to the end close to the pressure induction spring.

[0013] Preferably, the speed induction adjustment unit includes a speed induction piston, a speed induction spring, and a speed induction trigger assembly. One end of the speed induction piston is provided with a second ventilation port, and the other end thereof is connected to one end of the speed induction spring. The other end of the speed induction spring is connected to the housing. One end of the speed induction trigger assembly is located at the air inlet, and the other end thereof is in movable contact with the speed induction piston. The pressure change at the air inlet can drive the speed induction trigger assembly to move. The speed induction trigger assembly can drive the speed induction piston to move relative to the return air channel. When the second ventilation port moves to the corresponding position of the return air channel, the return air channels on both sides of the speed induction piston can be communicated through the second ventilation port.

[0014] Preferably, the speed induction trigger assembly includes a speed induction rod, a speed induction trigger link, and a speed induction trigger spring. The speed induction rod is located at the air inlet. The speed induction rod is in movable contact with one end of the speed induction trigger link. The other end of the speed induction trigger link is connected to one end of the speed induction trigger spring. The other end of the speed induction trigger spring is connected to the housing. The speed induction trigger link is provided with a first movement trigger portion at the corresponding position of the speed induction piston. The speed induction piston is provided with a second movement trigger portion at the corresponding position of the speed induction trigger link. During the relative movement process, the speed induction trigger link can form a squeezing contact with the second movement trigger portion through the first movement trigger portion to drive the relative movement of the speed induction piston.

[0015] Preferably, a second movement groove is formed inside the housing. The second movement groove is communicated with the return air channel. The speed induction piston moves relatively inside the second movement groove. The end of the speed induction spring away from the speed induction piston is connected to the second movement groove. The length direction of the second movement groove is perpendicular to the length direction of the return air channel, so that the movement direction of the speed induction piston is perpendicular to the flow direction of the return air inside the return air channel.

[0016] Preferably, a third movement groove is formed inside the housing. The third movement groove is communicated with the second movement groove. One end of the speed induction trigger link moves relatively inside the third movement groove. The end of the speed induction trigger spring away from the speed induction trigger link is connected to the third movement groove. The length direction of the third movement groove is parallel to the length direction of the return air channel.

[0017] Preferably, the speed induction rod includes a connecting sub-rod, a force-bearing sub-rod, and a triggering sub-rod. One end of the connecting sub-rod, the force-bearing sub-rod, and the triggering sub-rod are connected together. The other end of the connecting sub-rod is rotatably connected to the pipe wall corresponding to the air inlet. The other end of the force-bearing sub-rod extends to the center of the air inlet. The other end of the triggering sub-rod is in movable contact with the speed induction triggering link.

[0018] Preferably, the diameter of the second ventilation port gradually decreases from the end far away from the speed induction spring to the end close to the speed induction spring.

[0019] The beneficial effects of the present invention are as follows: By providing a speed induction adjustment unit and a pressure induction adjustment unit, the speed induction adjustment unit can sense the flow rate change at the air inlet and then control the on-off of the return air channel and the return air flow rate in the on-state. The pressure induction adjustment unit can sense the pressure change at the exhaust port and then control the on-off of the return air channel and the return air flow rate in the on-state; With the mutual cooperation of the speed induction adjustment unit and the pressure induction adjustment unit, it is possible to 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 rate of the return air channel in the on-state; On this basis, it is possible to dynamically adjust the high-pressure air return flow rate within a suitable range, so that the centrifugal compressor can operate stably within the designed operating conditions range, avoid large losses caused by the interruption of customer production due to protective shutdown, protect the efficient and stable operation of the centrifugal compressor, improve the operating efficiency, and better meet the high-stability requirements of customers. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a sectional view structure diagram of the anti-surge device of the centrifugal compressor of the present invention; Figure 2 It is a partial structure diagram of the anti-surge device of the centrifugal compressor of the present invention; Figure 3 It is an operating condition range diagram of the anti-surge device of the centrifugal compressor of the present invention; In the figure, 1 is the housing; 11 is the return air channel; 12 is the first moving groove body; 13 is the second moving groove body; 14 is the third moving groove body; 2. Speed induction adjustment unit; 21. Speed induction piston; 211. Second ventilation port; 212. Second movement trigger part; 22. Speed induction spring; 23. Speed induction trigger assembly; 231. Speed induction rod; 2311. Connecting sub-rod; 2312. Force-bearing sub-rod; 2313. Trigger sub-rod; 232. Speed induction trigger connecting rod; 2321. First movement trigger part; 233. Speed induction trigger spring; 3. Pressure induction adjustment unit; 31. Pressure induction piston; 311. First ventilation port; 32. Pressure induction spring; 4. Air inlet; 5. Exhaust port; 61. Working area; 62. Surge area; 63. Extended working area; 71. Speed opening line; 72. Pressure opening line; 73. Design surge line; 74. Design surge warning line; 75. Choke line; 76. Choke warning line; 77. Rotation speed line. Detailed implementation manners

[0022] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present invention without any creative efforts fall within the scope protected by the present invention. In the description of the present invention, it should be understood that the terms "center", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "side", etc. indicate the orientation or positional relationship based on the Figure 1 orientation or positional relationship shown, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0023] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0024] Refer to Figures 1 to 3, the present invention provides a centrifugal compressor anti-surge device, which includes a housing 1, a speed induction adjustment unit 2 and a pressure induction adjustment unit 3; A return gas passage 11 is provided inside the housing 1, and both ends of the return gas passage 11 are respectively communicated with the suction port 4 and the discharge port 5 of the centrifugal compressor; The speed induction adjustment unit 2 is connected to the housing 1 and is located on one side of the suction port 4, and the pressure induction adjustment unit 3 is connected to the housing 1 and is located on one side of the discharge port 5; The speed induction adjustment unit 2 can sense the flow rate change at the suction port 4 and then control the on-off of the return gas passage 11 and the return gas flow rate in the passage state, and the pressure induction adjustment unit 3 can sense the pressure change at the discharge port 5 and then control the on-off of the return gas passage 11 and the return gas flow rate in the passage state.

[0025] With the mutual cooperation of the speed induction adjustment unit 2 and the pressure induction adjustment unit 3, it is possible to dynamically adjust whether the return gas passage 11 is opened or closed according to the actual flow rate and pressure requirements, and can dynamically adjust the specific return gas flow rate of the return gas passage 11 in the passage state; On this basis, it is possible to dynamically adjust the high-pressure gas return flow rate within a suitable range, so that the centrifugal compressor can operate stably within the design operating conditions, avoid large losses caused by the interruption of customer production due to protective shutdown, protect the efficient and stable operation of the centrifugal compressor, improve the operation efficiency, and better meet the high stability requirements of customers.

[0026] The centrifugal compressor anti-surge device is preferably composed of completely mechanical parts, so as to be fearless of harsh environments such as high temperature and high pressure.

[0027] As an optional implementation manner, the pressure induction adjustment unit 3 includes a pressure induction piston 31 and a pressure induction spring 32. One end of the pressure induction piston 31 is provided with a first air vent 311 and the other end thereof is connected to one end of the pressure induction spring 32, and the other end of the pressure induction spring 32 is connected to the housing 1; The discharge port 5 is in a communicating state with the space where the pressure induction piston 31 is located. Therefore, the pressure change at the discharge port 5 can drive the pressure induction piston 31 to move relative to the return gas passage 11, squeeze and drive the pressure induction piston 31 to move rightward as shown in the attachment Figure 2 When the first air vent 311 moves to the corresponding position of the return gas passage 11, the return gas passages 11 on both sides of the pressure induction piston 31 can be connected through the first air vent 311. At this time, the return gas passage 11 forms a connected state at the pressure induction adjustment unit 3; It should be noted that the diameter of the first ventilation port 311 gradually decreases from the end far away from the pressure sensing spring 32 to the end close to the pressure sensing spring 32. Therefore, when the pressure sensing piston 31 moves to the right as shown in the attachment Figure 1 during the process, the first ventilation port 311 can gradually increase the flow rate of the reflux gas. By optimizing the design of the diameter of the first ventilation port 311, dynamic adjustment is further realized.

[0028] In order to set the pressure sensing piston 31 and the pressure sensing spring 32 more reasonably, preferably, a first moving groove 12 is formed inside the housing 1, and the first moving groove 12 is communicated with the reflux gas passage 11; The pressure sensing piston 31 moves relatively inside the first moving groove 12. One end of the pressure sensing piston 31 far away from the pressure sensing spring 32 contacts one end of the first moving groove 12, and one end of the pressure sensing spring 32 far away from the pressure sensing piston 31 is connected to the other end of the first moving groove 12. The length direction of the first moving groove 12 is perpendicular to the length direction of the reflux gas passage 11, so that the moving direction of the pressure sensing piston 31 is perpendicular to the flowing direction of the reflux gas inside the reflux gas passage 11.

[0029] As an optional implementation manner, the speed sensing and adjusting unit 2 includes 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 ventilation port 211 and the other end thereof is connected to one end of the speed sensing spring 22, and 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 inlet 4 and the other end thereof is in movable contact with the speed sensing piston 21. The pressure change at the air inlet 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 reflux gas passage 11. When the second ventilation port 211 moves to the corresponding position of the reflux gas passage 11, the reflux gas passages 11 on both sides of the speed sensing piston 21 can be communicated through the second ventilation port 211. At this time, the reflux gas passage 11 forms a communication state at the speed sensing and adjusting unit 2; It should be noted that the diameter of the second ventilation port 211 gradually decreases from the end far away from the speed sensing spring 22 to the end close to the speed sensing spring 22. Therefore, when the speed sensing piston 21 moves to the right as shown in the attachment Figure 1 during the process, the second ventilation port 211 can gradually increase the flow rate of the reflux gas. By optimizing the design of the diameter of the second ventilation port 211, dynamic adjustment is further realized.

[0030] As an alternative implementation, the speed induction trigger assembly 23 includes a speed induction rod 231, a speed induction trigger link 232, and a speed induction trigger spring 233; The speed induction rod 231 is located at the air inlet 4. The speed induction rod 231 is in movable contact with one end of the speed induction trigger link 232. The other end of the speed induction trigger link 232 is connected to one end of the speed induction trigger spring 233. The other end of the speed induction trigger spring 233 is connected to the housing 1; Furthermore, a first moving trigger portion 2321 is provided at a corresponding position of the speed induction trigger link 232 with respect to the speed induction piston 21. A second moving trigger portion 212 is provided at a corresponding position of the speed induction piston 21 with respect to the speed induction trigger link 232. During the relative movement of the speed induction trigger link 232, the second moving trigger portion 212 can be squeezed and contacted by the first moving trigger portion 2321 to drive the relative movement of the speed induction piston 21; Here, the first moving trigger portion 2321 can preferably be in the structural form of a squeezing contact block, and the second moving trigger portion 212 can preferably be an inclined contact surface. Through the inclined setting form, the relative movement of the speed induction trigger link 232 in the up and down direction can be correspondingly converted into the relative movement of the speed induction piston 21 in the left and right direction.

[0031] As an alternative implementation, a second moving groove 13 is formed inside the housing 1. The second moving groove 13 communicates with the return air passage 11. The speed induction piston 21 moves relatively inside the second moving groove 13. One end of the speed induction spring 22 away from the speed induction piston 21 is connected to the second moving groove 13. The length direction of the second moving groove 13 is perpendicular to the length direction of the return air passage 11, so that the moving direction of the speed induction piston 21 is perpendicular to the flowing direction of the return air inside the return air passage 11.

[0032] As an alternative implementation, a third moving groove 14 is formed inside the housing 1. The third moving groove 14 communicates with the second moving groove 13. One end of the speed induction trigger link 232 moves relatively inside the third moving groove 14. One end of the speed induction trigger spring 233 away from the speed induction trigger link 232 is connected to the third moving groove 14. The length direction of the third moving groove 14 is parallel to the length direction of the return air passage 11.

[0033] As an alternative implementation, the speed induction rod 231 includes a connecting sub-rod 2311, a force-bearing sub-rod 2312, and a triggering sub-rod 2313; One end of the connecting sub-rod 2311, the force-bearing sub-rod 2312, and the triggering sub-rod 2313 are all connected together; The other end of the connecting sub-rod 2311 is rotatably connected to the pipe wall corresponding to the air suction port 4. Therefore, the entire speed induction rod 231 can rotate relative to the connection point; The other end of the force-bearing sub-rod 2312 extends to the center of the air suction port 4. The force-bearing sub-rod 2312 can fully contact the air flow at the air suction port 4, and the air flow can push the force-bearing sub-rod 2312 to rotate relatively; The other end of the trigger sub-rod 2313 is in movable contact with the bottom end of the speed induction trigger link 232. When the speed induction rod 231 rotates, the trigger sub-rod 2313 exerts an actual force on the speed induction trigger link 232; When the flow rate is relatively large, the speed induction rod 231 can rotate counterclockwise. The trigger sub-rod 2313 exerts an upward force on the speed induction trigger link 232, raising the height of the speed induction trigger link 232, causing the speed induction piston 21 to move to the left; When the flow rate is relatively small, the speed induction rod 231 can rotate clockwise by relying on gravity. The trigger sub-rod 2313 no longer exerts an upward force on the speed induction trigger link 232, lowering the height of the speed induction trigger link 232, causing the speed induction piston 21 to move to the right.

[0034] Refer to Figure 3 , which is the operating condition range diagram of the centrifugal compressor after applying the anti-surge device mentioned in the present invention. There are two coordinate axes in the figure. V is the flow rate at the air suction port 4, with the unit of m 3 / min, and P is the pressure at the air exhaust port 5, with the unit of kPa.

[0035] The speed opening line 71 in the figure is the speed value designed according to requirements. When the flow rate at the air suction port 4 is higher than the designed value, the speed induction piston 21 can close the return air channel 11 in cooperation with the speed induction spring 22. When the flow rate at the air suction port 4 is lower than the designed value, the speed induction trigger link 232 can drive the speed induction piston 21 to open the return air channel 11, and can dynamically adjust the opening degree according to the high or low flow rate, so as to control the return air flow rate well and avoid too large a return air volume, resulting in too low compressor efficiency.

[0036] The pressure opening line 72 in the figure is the pressure value designed according to requirements. When the pressure at the air exhaust port 5 is higher than the designed value, the pressure induction piston 31 can open the return air channel 11. When the pressure at the air exhaust port 5 is lower than the designed value, the pressure induction piston 31 can close the return air channel 11 in cooperation with the pressure induction spring 32, and can dynamically adjust the opening degree according to the high or low pressure, so as to control the return air flow rate well and avoid too large a return air volume, resulting in too low compressor efficiency; In the figure, the designed surge line 73 represents that for a centrifugal compressor that should operate normally within the working area 61, if it crosses the designed surge line 73 and enters the left side of the designed surge line 73, the centrifugal compressor will experience severe periodic oscillations, which may cause damage to the centrifugal compressor; In the figure, the designed surge warning line 74 represents that it serves as a warning before entering the left side of the designed surge line 73. When the designed surge warning line 74 is crossed, the device will alarm, indicating that it may enter the surge area 62; In the figure, the choke line 75 represents that when it crosses the choke line 75 and enters the right side of the choke line 75, the suction capacity of the centrifugal compressor has reached its upper limit, resulting in choking; In the figure, the choke warning line 76 represents that it serves as a warning before entering the right side of the choke line 75. When the choke warning line 76 is crossed, the device will alarm, indicating that it may enter the choke line 75; In the figure, the speed line 77 is a set of lines that are first designed and then obtained through testing. The speed line 77 defines the performance of the centrifugal compressor and can assist in obtaining the range of the working area 61.

[0037] When the centrifugal compressor is operating normally within the working area 61 (represented by the shaded part in the Figure 3 figure), either because the flow rate at the suction port 4 of the centrifugal compressor is higher than the designed value (to the right of the speed opening line 71), the speed sensing piston 21 is in the closed state, or because the pressure at the discharge port 5 of the centrifugal compressor is lower than the designed value (below the pressure opening line 72), the pressure sensing piston 31 is in the closed state. At this time, a reflux gas channel cannot be formed, and the centrifugal compressor can operate efficiently according to the actual working conditions; It should be noted that although there is a certain area to the left of the speed opening line 71 and above the pressure opening line 72 in the working area 61, the range of this area is small, and its application range in actual applications is very small. In this embodiment, not much attention is paid to this area.

[0038] 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.

[0039] The working principle of the anti-surge device mentioned in the present invention is: When the centrifugal compressor is working normally Figure 3 When inside the working area 61 shown; 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. 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; 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. In the low flow velocity and low pressure area, the pressure sensing spring 32 drives the pressure sensing piston 31 to move leftward. The high-pressure gas cannot pass through the pressure sensing piston 31. At this time, although the flow velocity is small, the velocity sensing rod 231 can rotate clockwise, reducing the height of the velocity sensing trigger link 232, causing the velocity sensing piston 21 to move rightward. At this time, the velocity sensing piston 21 can allow gas to pass through, but the overall gas still cannot pass through, so there will be no backflow air supply to prevent surging. Only when the operating point of the centrifugal compressor crosses the originally designed working area 61 and enters the newly designed extended working area 63, at this time, the operating point is located on the left side of the velocity opening line 71 and above the pressure opening line 72. At this time, the high-pressure drives the pressure sensing piston 31 to move rightward, and the velocity sensing rod 231 can rotate clockwise, reducing the height of the velocity sensing trigger link 232, causing the velocity sensing piston 21 to move rightward. At this time, the high-pressure gas at the exhaust port 5 can sequentially pass through the pressure sensing piston 31 and the velocity sensing piston 21 and enter the compressor suction port 4, forming a backflow air supply to prevent surging and ensuring that the compressor still operates stably. Moreover, when the exhaust pressure is higher and the suction velocity is lower, surging is more likely to occur. At this time, the pressure sensing piston 31 and the velocity sensing piston 21 move more to the right, the backflow area is larger, which leads to more backflow air supply. Still, surging can be avoided. At the same time, due to the reasonable design of the piston curve, when the backflow air supply is sufficient, the efficiency of the centrifugal compressor can still be maintained without being too low.

[0040] It is also possible to conduct a more refined structural design for each component of the velocity sensing adjustment unit 2 and the pressure sensing adjustment unit 3, highly customize and adjust the backflow gas volume, and flexibly adjust the position and size of the extended working area 63 according to the actual operating conditions of the customer, so as to perfectly adapt to the customer's needs, ensure the operating stability of the compressor, and have a larger operating range.

[0041] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A centrifugal compressor anti-surge device, characterized in that, It includes a housing (1), a speed induction adjustment unit (2) and a pressure induction adjustment unit (3). A return air channel (11) is arranged inside the housing (1). Both ends of the return air channel (11) are respectively communicated with the suction port (4) and the exhaust port (5) of the centrifugal compressor. The speed induction adjustment unit (2) is connected to the housing (1) and is located on one side of the suction port (4). The pressure induction adjustment unit (3) is connected to the housing (1) and is located on one side of the exhaust port (5). The speed induction adjustment unit (2) can sense the flow velocity change at the suction port (4) and then control the on-off of the return air channel (11) and the return air flow rate in the on-state. The pressure induction adjustment unit (3) can sense the pressure change at the exhaust port (5) and then control the on-off of the return air channel (11) and the return air flow rate in the on-state.

2. The anti-surge device for a centrifugal compressor according to claim 1, characterized in that The pressure induction adjustment unit (3) includes a pressure induction piston (31) and a pressure induction spring (32). One end of the pressure induction piston (31) is provided with a first air vent (311) and the other end thereof is connected to one end of the pressure induction spring (32). The other end of the pressure induction spring (32) is connected to the housing (1). The pressure change at the exhaust port (5) can drive the pressure induction piston (31) to move relative to the return air channel (11). When the first air vent (311) moves to the corresponding position of the return air channel (11), the return air channels (11) on both sides of the pressure induction piston (31) can be communicated through the first air vent (311).

3. The surge prevention device for a centrifugal compressor according to claim 2, characterized in that, A first moving groove body (12) is formed inside the housing (1). The first moving groove body (12) is communicated with the return air channel (11). The pressure induction piston (31) moves relatively inside the first moving groove body (12). One end of the pressure induction piston (31) away from the pressure induction spring (32) contacts one end of the first moving groove body (12). The other end of the pressure induction spring (32) away from the pressure induction piston (31) is connected to the other end of the first moving groove body (12). The length direction of the first moving groove body (12) is perpendicular to the length direction of the return air channel (11), so that the moving direction of the pressure induction piston (31) is perpendicular to the flowing direction of the return air inside the return air channel (11).

4. The surge prevention device for a centrifugal compressor according to claim 2, wherein, The diameter of the first air vent (311) gradually decreases from the end away from the pressure induction spring (32) to the end close to the pressure induction spring (32).

5. The surge prevention device for a centrifugal compressor according to claim 1, characterized in that, The speed induction adjustment unit (2) includes a speed induction piston (21), a speed induction spring (22) and a speed induction trigger assembly (23). One end of the speed induction piston (21) is provided with a second ventilation port (211), and the other end thereof is connected to one end of the speed induction spring (22). The other end of the speed induction spring (22) is connected to the housing (1). One end of the speed induction trigger assembly (23) is located at the air inlet (4), and the other end thereof is in movable contact with the speed induction piston (21). The pressure change at the air inlet (4) can drive the speed induction trigger assembly (23) to move. The speed induction trigger assembly (23) can drive the speed induction piston (21) to move relative to the return air channel (11). When the second ventilation port (211) moves to the corresponding position of the return air channel (11), the return air channels (11) on both sides of the speed induction piston (21) can be communicated through the second ventilation port (211).

6. The surge prevention device for a centrifugal compressor according to claim 5, wherein, The speed induction trigger assembly (23) includes a speed induction rod (231), a speed induction trigger link (232) and a speed induction trigger spring (233). The speed induction rod (231) is located at the air inlet (4). The speed induction rod (231) is in movable contact with one end of the speed induction trigger link (232). The other end of the speed induction trigger link (232) is connected to one end of the speed induction trigger spring (233). The other end of the speed induction trigger spring (233) is connected to the housing (1). The speed induction trigger link (232) is provided with a first movement trigger portion (2321) at the corresponding position of the speed induction piston (21). The speed induction piston (21) is provided with a second movement trigger portion (212) at the corresponding position of the speed induction trigger link (232). During the relative movement process, the speed induction trigger link (232) can form a squeezing contact with the second movement trigger portion (212) through the first movement trigger portion (2321) to drive the relative movement of the speed induction piston (21).

7. The anti-surge device for a centrifugal compressor according to claim 6, characterized in that, A second movement groove body (13) is formed inside the housing (1). The second movement groove body (13) is communicated with the return air channel (11). The speed induction piston (21) moves relatively inside the second movement groove body (13). The end of the speed induction spring (22) away from the speed induction piston (21) is connected to the second movement groove body (13). The length direction of the second movement groove body (13) is perpendicular to the length direction of the return air channel (11), so that the movement direction of the speed induction piston (21) is perpendicular to the flow direction of the return air inside the return air channel (11).

8. The anti-surge device for a centrifugal compressor according to claim 7, wherein, A third moving groove (14) is formed inside the housing (1). The third moving groove (14) communicates with the second moving groove (13). One end of the speed induction trigger link (232) moves relatively inside the third moving groove (14). One end of the speed induction trigger spring (233) away from the speed induction trigger link (232) is connected to the third moving groove (14). The length direction of the third moving groove (14) is parallel to the length direction of the return gas passage (11).

9. The surge prevention device for a centrifugal compressor according to claim 6, characterized in that, The speed induction rod (231) includes a connecting sub-rod (2311), a force-bearing sub-rod (2312) and a trigger sub-rod (2313). One ends of the connecting sub-rod (2311), the force-bearing sub-rod (2312) and the trigger sub-rod (2313) are commonly connected together. The other end of the connecting sub-rod (2311) is rotatably connected to the pipe wall corresponding to the suction port (4). The other end of the force-bearing sub-rod (2312) extends to the center of the suction port (4). The other end of the trigger sub-rod (2313) is in movable contact with the speed induction trigger link (232).

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

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