Circulating fan control device of air separation system

Abstract

The invention relates to the technical field of air separation system control, in particular to a circulating fan control device of an air separation system, which comprises a circulating fan, a rotating speed control system and an inclination angle control system, the circulating fan is arranged at the upper part of a cooling tower, the rotating speed control system is connected with the circulating fan, and the inclination angle control system is connected with fan blades; starting and speed increasing of the circulating fan are controlled through the temperature of cooling water in a cooling tower filler layer, the rotating speed change of the circulating fan is controlled through a gearbox structure, energy consumption and vibration in a high-speed state are reduced, the included angle between fan blades and the horizontal plane can be changed under the high-temperature condition, the contact area between the fan blades and air during rotation is increased, and the cooling effect is improved. Diffusion of hot air is accelerated; the problems that when the difference between the outlet water temperature and the cooling water temperature in the cooling tower is large, hysteresis exists in starting of the circulating fan, the cooling effect is not obviously improved after the rotating speed is increased to a certain range, and energy consumption is increased are solved.

Description

Technical Field

[0001] The invention relates to the technical field of air separation system control, and in particular to a circulating fan control device of an air separation system. Background Art

[0002] The air separation system is an industrial equipment that separates different gases by liquefying air and utilizing the differences in boiling points of components in the air. The air separation system is mainly divided into six steps when working: compression, pre-cooling, liquefaction, distillation separation, expansion and collection. Currently, the gases produced by the air separation system are widely used in many industries.

[0003] In the air separation system, a large amount of heat will be generated after the air is compressed, and its temperature must be reduced to a level suitable for liquefaction by cooling. The circulating fan exchanges heat with the compressed air through the circulating cooling medium to help the compressed air to be pre-cooled. At present, the air separation system manually evaluates the circulating water temperature and adjusts the required fan speed by the water temperature until the circulating water temperature reaches the required temperature. The manual adjustment has hysteresis and the fan speed is not compatible with the water temperature, which will generate a large amount of air compression energy consumption and increase the cost. The prior art has proposed a good solution to this problem, such as a circulating fan control method and device based on an air separation system with patent publication number CN117128183B. Through intelligent control of the circulating fan, according to the current circulating water temperature and external environmental parameters, a computer program is used to intelligently analyze the water temperature fluctuation range of the air separation system, and the start and stop working state and speed of the fan are adjusted in stages, so that the working state of the fan is adapted to the change of the circulating water temperature, thereby reducing the working energy consumption generated when the air separation system water temperature is adjusted.

[0004] Although the existing technology has solved the problem of increased air compression energy consumption caused by hysteresis in manually adjusting the start and stop of the circulating fan and adjusting the circulating fan speed to match the circulating water temperature, there are still the following problems: in the pre-cooling system, cooling water is usually circulated in a cooling tower. The cooling water enters the heat exchanger to absorb the heat of the compressed gas and then returns to the cooling tower. Under the action of the circulating fan, the heat in the cooling water rises. After cooling, the cooling water flows from the cooling tower to the heat exchanger for circulation. When the circulating fan is intelligently controlled, it is necessary to obtain the outlet water temperature data and the external temperature data and perform calculations. However, there is still hysteresis when monitoring the outlet water temperature. When the compressed air is continuously exchanged with heat, the water temperature returning from the heat exchanger to the cooling tower is quite different from the outlet water temperature. Due to the previous cycles The circulation will not cause the outlet water temperature to rise rapidly. At this time, the circulating fan does not increase its speed, and the high-temperature cooling water returning to the cooling tower cannot be cooled down quickly; when the outlet water temperature rises to the set range, increasing the circulating fan speed will not be able to quickly reduce the outlet water temperature. The heated cooling water enters the heat exchanger, which will cause the heat exchange efficiency to decrease, thereby increasing the air compression energy consumption; although the gradually increasing speed of the circulating fan can increase the air circulation volume, the increase in air circulation volume will gradually decrease with the increase in speed, and excessive speed may also cause the circulating fan noise to increase, energy consumption to increase, and even damage the components of the circulating fan. Therefore, under continuous working conditions, only increasing the speed of the circulating fan will not guarantee rapid cooling of the cooling water, and will also increase energy consumption.

[0005] In view of the above situation, in order to overcome the above technical problems, the present invention designs a circulation fan control device for an air separation system. Summary of the invention

[0006] The present invention provides a circulating fan control device for an air separation system, which solves the problem that when the difference between the outlet water temperature and the cooling water temperature returned to the cooling tower is large, there is a hysteresis in the start-up of the circulating fan, and after the speed increases to a certain range, the cooling effect will no longer be obvious and the energy consumption will be increased. The start-up and speed increase of the circulating fan are controlled by the cooling water temperature in the packing layer of the cooling tower to ensure that the outlet water temperature is controlled within a limited range, thereby improving the heat exchange efficiency and reducing the air compression energy consumption. The speed change of the circulating fan is controlled by the gearbox structure to ensure that the motor speed is constant and will not fluctuate, thereby reducing the energy loss caused by increasing the speed of the circulating fan under the condition of high cooling water temperature. In addition, under the condition of high temperature, the fan blades will change the angle between the horizontal plane, increase the contact area of ​​the fan blades with the air when rotating, and change the original axial air flow trend to a rapid heat dissipation with axial air flow as the main trend and radial air flow as the auxiliary trend, thereby improving the heat dissipation effect.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A circulating fan control device for an air separation system comprises a centrifugal compressor, a cooling tower, a heat exchanger and a fractionating tower; it also comprises a circulating fan, a speed control system and an inclination control system; the circulating fan comprises a fan shaft and fan blades; the fan shaft is arranged at the upper part of the cooling tower, and a circular array of rotating grooves is provided on the side wall of the fan shaft; the fan blades are installed in the rotating grooves; the speed control system is connected to the fan shaft, and the speed control system changes the transmission ratio with the fan shaft as the temperature rises or falls; the inclination control system is connected to the fan blades, and the speed control system performs an ascending or descending movement to drive the inclination control system to perform an ascending or descending movement, and the inclination control system drives the fan blades to rotate when performing an ascending or descending movement to increase or decrease the angle between the fan blades and the horizontal plane.

[0009] Preferably, the speed control system includes a motor, an input shaft, an output shaft, a speed gear set and a speed lever; the motor is connected to the top of the cooling tower; the input shaft is connected to the motor; the output shaft is connected to the circulating fan; the speed gear set is connected between the input shaft and the output shaft in a meshing transmission manner; the speed lever is connected to the output shaft.

[0010] In the above scheme, the speed of the circulating fan is controlled by using the gearbox principle. The speed is adjusted without changing the speed of the motor, which can make the circulating fan vibrate and make less noise when rotating at high speed, thereby extending the service life of the circulating fan. The speed of the circulating fan is directly changed according to the temperature change, and no external equipment is required to collect temperature data to change the output signal to achieve the purpose of changing the speed of the circulating fan. During the operation of the circulating fan, the higher the speed of the circulating fan, the greater the load the motor needs to bear. The introduction of the variable speed structure can transfer part of the load to the variable speed structure, thereby reducing the burden on the motor, helping to extend the service life of the motor and reduce the occurrence of mechanical failures. In addition, the motor speed remains unchanged instead of changing multiple times under temperature changes, which can avoid mechanical damage to components caused by frequent changes in speed and extend the service life of the motor.

[0011] Preferably, the clutch sleeve is slidably mounted on the output shaft; the sliding lever is connected to the clutch sleeve; a packing layer is provided in the middle of the cooling tower; the expansion cylinder is provided in the packing layer, and the expansion cylinder is filled with a thermal expansion medium; the return spring is connected between the expansion cylinder and the sliding lever.

[0012] In the above scheme, the thermal expansion medium expands after being heated and pushes the sliding lever upward. During the upward movement of the sliding lever, the clutch sleeve will switch the connected gear, thereby completing the speed switching process. In addition, since the expansion cylinder is connected to the packing layer of the cooling tower, the water temperature returning to the cooling tower can be fed back in real time, thereby quickly changing the speed of the circulating fan.

[0013] Preferably, the fan shaft is hollow inside and a fixed slide rod is arranged at the center, and a connecting block is arranged at the lower end of the fixed slide rod; the connecting block is connected to the output shaft.

[0014] In the above solution, the hollow design of the fan shaft places the inclination control system therein to save space and will not affect the flow of air in and out. Under the connection between the connecting block and the output shaft, the fan shaft as a whole will drive the fan blades to rotate at the same speed as the output shaft.

[0015] Preferably, a push switch is provided in the middle of the expansion cylinder; the diameter of the upper section of the sliding rod is smaller than the diameter of the lower section and the diameter of the lower section is equal to the diameter of the inner wall of the expansion cylinder, the connection position between the upper section and the lower section of the sliding rod is a conical structure transition, and the upper section does not contact the push switch when the sliding rod slides up and down.

[0016] In the above scheme, when the temperature has not risen to the specified range, the circulating fan will not be started even if the sliding lever slides upward. At this time, the air in the cooling tower will dissipate heat in the natural flow. Since the cooling water temperature is relatively low, the cooling demand of the cooling water can be met under natural air convection, thereby saving energy.

[0017] Preferably, the inclination control system includes a transfer groove, a lifting platform and an adjusting spring; the transfer groove is opened at the lower part of the fan shaft; the lifting platform sliding sleeve is arranged on the fixed sliding rod; the adjusting spring is connected between the lifting platform and the fan blade.

[0018] In the above scheme, when the sliding lever moves upward, the lifting platform will move upward, and when the lifting platform is lifted, the inclination angle of the fan blades will change. In order to reduce energy consumption under low-speed operation, the fan blade angle is set to 30 degrees, which can enable the fan blades to quickly increase the hot air flow in the cooling tower in the axial direction of the wind direction, and at an angle of 30 degrees, the resistance to the rotation of the fan blades is small, so that the motor bears less load at low speed and saves more energy. When the angle of the fan blade is 45 degrees, the contact area between the fan blade and the air increases during the rotation process. The increased contact area helps to accelerate the process of heat conduction and convection, thereby improving the heat dissipation performance. The larger inclination angle makes the airflow more dispersed, thereby increasing the flow rate of air on and around the blade surface, and the air The faster the air flows, the more efficient the heat removal is, which is beneficial to heat dissipation. By guiding the airflow into more lateral and tangential flows, heat can be more effectively removed from the fan blades and the area around the heat source. A larger fan blade angle (45 degrees) will cause more airflow disturbances, which can make the air flow more uniform and reduce local airflow stagnation, thereby further improving the heat dissipation effect. Compared with a 30-degree angle, the resistance to the rotation of the fan blades at a 45-degree angle will increase, increasing the load on the circulating fan, so the fan blade angle is only changed when the temperature exceeds the limit value; under the action of the adjusting spring, the fan blades will keep the fan blades at an angle of 30 degrees with the horizontal plane when the lifting platform does not move upward, ensuring the axial flow guidance effect and smaller rotation resistance.

[0019] Preferably, the fan blades include rotating blades and a driving plate; the rotating blades are installed in rotating grooves; the driving plate is connected to the rotating blades and is arranged inside the fan shaft, and a hemispherical groove is opened on the driving plate; the lifting platform includes a sliding platform body and a spherical push rod; the sliding platform body is slidably installed on a fixed sliding rod; the spherical push rod is connected to the upper end of the sliding platform body and the sphere at its upper end is located in the hemispherical groove.

[0020] In the above scheme, the upward movement of the lifting platform can make the rotating blades rotate with the driving plate, thereby helping the circulating fan to change the angle between the fan blades and the horizontal plane. When the heat accumulated in the upper part of the cooling tower is too high and the cooling water temperature in the packing layer is high, the circulating fan can change the angle of attack of the fan blades while increasing the speed, thereby helping the circulating fan to enhance the heat dissipation capacity, so that under low-speed conditions, the blade inclination angle is smaller and the rotation resistance is smaller, which can further save energy. Under high-speed conditions, the inclination angle can be changed to further increase the heat dissipation speed, thereby avoiding increasing the speed continuously without significantly improving the heat dissipation effect.

[0021] Preferably, the inner wall diameter of the hemispherical groove is larger than the diameter of the sphere at the upper end of the spherical push rod, and when the angle between the rotating blade and the horizontal plane is between 30 degrees and 45 degrees, the sphere at the upper end of the spherical push rod is located inside the hemispherical groove.

[0022] In the above scheme, since the diameter of the spherical push rod is smaller than the diameter of the hemispherical groove on the driving plate, the spherical push rod can slide in the hemispherical groove when the lifting platform is lifted to avoid motion interference. At this time, there is no need for the lifting platform to rotate during the lifting process, thereby ensuring the high-speed rotation of the circulating fan.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. Compared with the existing methods, the present invention uses a thermal expansion medium to monitor the cooling water temperature in the packing layer in real time, so that the equipment does not consume energy when dissipating heat under natural air flow. When the water temperature in the packing layer rises to a limited range, the thermal expansion medium absorbs heat and expands to quickly start the motor. Monitoring the cooling water temperature in the packing layer can ensure that the cooling water returned to the cooling tower is quickly cooled when the temperature is high. Compared with the method of monitoring the outlet water temperature and performing calculation and analysis, the hysteresis effect is smaller, thereby ensuring that the outlet water temperature of the cooling tower is always controlled within an appropriate range, improving heat exchange efficiency and reducing air compressor energy consumption, while maintaining the motor in a low-load and low-speed state, further saving energy consumption.

[0025] 2. The present invention sets a speed control system and utilizes a gearbox structure to replace the method of adjusting the working voltage of the motor to change the speed of the circulating fan. The speed of the circulating fan can be changed by maintaining the same speed of the motor after starting. Mechanical damage to components caused by frequent changes in speed can be avoided, and part of the load is transferred to the speed change structure, thereby reducing the burden on the motor, helping to extend the service life of the motor and reduce the occurrence of mechanical failures. At the same time, the rotation process of the circulating fan will be smoother, reducing the generation of vibration and noise, and can save the energy consumption required for high-speed rotation of the circulating fan.

[0026] 3. The present invention provides an inclination control system. When the cooling water temperature is at a relatively low temperature, the angle between the fan blades of the circulating fan and the horizontal plane is maintained at 30 degrees, thereby ensuring that the circulating fan can quickly send the hot air out of the cooling tower in an axial flow trend when rotating, ensuring that the temperature in the cooling tower is maintained within an appropriate range, and the 30-degree angle can make the air resistance of the fan blades during the rotation process smaller, further reducing the load of the circulating fan at a low speed, thereby reducing energy consumption; and when the cooling water temperature is too high, in order to ensure that the cooling water temperature can be quickly reduced, while the speed of the circulating fan is increased, the angle between the blades and the horizontal plane will become 45 degrees, thereby increasing the contact area with the air during rotation, greatly increasing the air circulation per unit time, and a larger inclination angle will make the airflow more dispersed, thereby increasing the flow speed of the air on and around the blade surface. The faster the air flow speed, the higher the heat removal efficiency, so it is beneficial to heat dissipation, and at this time, the flow direction of the airflow will be mainly axial and supplemented by radial, so that the heat can be accelerated to diffuse, so that the cooling water can be quickly cooled, ensuring the heat exchange efficiency and reducing the air compression energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is the overall structure diagram of the present invention;

[0029] Figure 2 It is a schematic diagram of the internal structure of a cooling tower of the present invention;

[0030] Figure 3 A perspective view of the internal structure of the fan shaft of the present invention;

[0031] Figure 4 for Figure 2 A magnified view of the structure at center;

[0032] Figure 5 It is a cross-sectional view of a cooling tower of the present invention;

[0033] Figure 6 It is a schematic diagram of the connection between the speed control system and the inclination control system of the present invention;

[0034] Figure 7 is an internal cross-sectional view of the tilt control system of the present invention;

[0035] Figure 8 for Figure 7A magnified view of the structure at B in the middle;

[0036] In the figure: 1. centrifugal compressor; 2. cooling tower; 21. packing layer; 3. heat exchanger; 4. fractionating tower; 5. circulating fan; 51. fan shaft; 511. rotating groove; 512. fixed sliding rod; 513. connecting block; 52. fan blade; 521. rotating blade; 522. driving plate; 5221. hemispherical groove; 6. speed control system; 61. motor; 62. input shaft; 63. output shaft; 64. speed change gear set; 65. speed change lever; 651. clutch sleeve; 652. sliding lever; 653. expansion cylinder; 6531. push switch; 654. reset spring; 7. inclination control system; 71. adapter groove; 72. lifting platform; 721. sliding platform body; 722. spherical push rod; 73. adjusting spring. DETAILED DESCRIPTION

[0037] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0038] See also Figures 1 to 8 The present invention provides a circulating fan control device for an air separation system, and the technical solution is as follows:

[0039] As a specific embodiment of the present invention, refer to Figure 1 , Figure 2 and Figure 3 A circulating fan control device for an air separation system comprises a centrifugal compressor 1, a cooling tower 2, a heat exchanger 3 and a fractionating tower 4; further comprising a circulating fan 5, a speed control system 6 and an inclination control system 7; the circulating fan 5 comprises a fan shaft 51 and fan blades 52; the fan shaft 51 is arranged at the upper part of the cooling tower 2, and a rotating groove 511 is provided in a circumferential array on the side wall of the fan shaft 51; the fan blades 52 are installed in the rotating grooves 511; the speed control system 6 is connected to the fan shaft 51, and the speed control system 6 changes the transmission ratio with the fan shaft 51 as the temperature rises or falls; the inclination control system 7 is connected to the fan blades 52, and the speed control system 6 performs an ascending or descending movement to drive the inclination control system 7 to perform an ascending or descending movement, and when the inclination control system 7 performs an ascending or descending movement, it drives the fan blades 52 to rotate to increase the angle between the fan blades and the horizontal plane or to reduce the angle between the fan blades and the horizontal plane.

[0040] As a specific embodiment of the present invention, refer to Figure 4The speed control system 6 includes a motor 61, an input shaft 62, an output shaft 63, a speed gear set 64 and a speed lever 65; the motor 61 is connected to the top of the cooling tower 2; the input shaft 62 is connected to the motor 61; the output shaft 63 is connected to the circulating fan 5; the speed gear set 64 is connected between the input shaft 62 and the output shaft 63 in a meshing transmission mode; the speed lever 65 is connected to the output shaft 63, and a certain gap is maintained between the gear connected to the output shaft 63 in the speed gear set 64 and the output shaft 63, so as to ensure that the gear not connected to the synchronous gear of the speed lever 65 will not drive the output shaft 63. The speed of the circulating fan 5 is controlled by using the gearbox principle, and the speed is adjusted without changing the speed of the motor 61, so that the circulating fan 5 can have less vibration and noise under high-speed rotation, thereby extending the service life of the circulating fan 5, and the speed of the circulating fan 5 is directly changed according to the temperature change, and the purpose of changing the speed of the circulating fan 5 is achieved without the need for external equipment to collect temperature data and change the output signal. During the operation of the circulating fan 5, the higher the speed of the circulating fan 5, the greater the load that the motor 61 needs to bear. The introduction of the variable speed structure can transfer part of the load to the variable speed structure, thereby reducing the burden on the motor 61, helping to extend the service life of the motor 61, and reducing the occurrence of mechanical failures. In addition, the speed of the motor 61 remains unchanged instead of changing multiple times under temperature changes, which can avoid mechanical damage to components caused by frequent changes in speed and extend the service life of the motor 61.

[0041] As a specific embodiment of the present invention, refer to Figure 4 , Figure 5 and Figure 6 The shift lever 65 includes a clutch sleeve 651, a sliding lever 652, an expansion cylinder 653 and a return spring 654; the clutch sleeve 651 is slidably mounted on the output shaft 63. After the clutch sleeve 651 is connected to the gear connected to the output shaft 63 in the speed gear set 64, the clutch sleeve 651 will establish a connection relationship between the gear and the output shaft 63, so that the output shaft 63 has the same rotation speed as the gear; the sliding lever 652 is connected to the clutch sleeve 651; a packing layer 21 is provided in the middle of the cooling tower 2; the expansion cylinder 653 is provided in the packing layer 21, and the expansion cylinder 653 is filled with a heat expansion medium. The outer wall of the expansion cylinder 653 is made of a high thermal conductivity material to ensure that the heat expansion medium can fully respond to temperature changes; the return spring 654 is connected between the expansion cylinder 653 and the sliding lever 652. After being heated, the thermal expansion medium expands and pushes the sliding lever 652 upward. During the upward movement, the sliding lever 652 will cause the clutch sleeve 651 to switch the connected gear, thereby completing the speed switching process. In addition, since the expansion cylinder 653 is connected to the packing layer 21 of the cooling tower 2, the water temperature returning to the cooling tower 2 can be fed back in real time, thereby quickly changing the speed of the circulating fan 5.

[0042] As a specific embodiment of the present invention, refer to Figure 6 The fan shaft 51 is hollow inside and has a fixed slide bar 512 at the center. A connecting block 513 is provided at the lower end of the fixed slide bar 512. The connecting block 513 is connected to the output shaft 63. The hollow design of the fan shaft 51 saves space by placing the inclination control system 7 therein, and does not affect the flow of air in and out. Under the connection between the connecting block 513 and the output shaft 63, the fan shaft 51 as a whole will drive the fan blades 52 to rotate at the same speed as the output shaft 63.

[0043] As a specific embodiment of the present invention, refer to Figure 2 , Figure 5 and Figure 6 A push switch 6531 is provided in the middle of the expansion cylinder 653. When the push switch 6531 is kept pressed to the bottom, the motor 61 will be maintained in the starting state. When the push switch 6531 is not pressed, it will automatically reset, and the circuit of the motor 61 will be disconnected at this time. The diameter of the upper section of the sliding lever 652 is smaller than the diameter of the lower section, and the diameter of the lower section is equal to the inner wall diameter of the expansion cylinder 653. The connection position between the upper and lower sections of the sliding lever 652 is a conical structure transition. The conical structure can smoothly press the push switch 6531 when the lower section of the sliding lever 652 contacts the push switch 6531, avoiding jamming. When the sliding lever 652 slides up and down, the upper section does not contact the push switch 6531. When the temperature has not risen to the specified range, the circulation fan 5 will not be started even if the sliding lever 652 slides upward. At this time, the air in the cooling tower 2 will dissipate the heat in the natural flow. Since the cooling water temperature is relatively low, the cooling of the cooling water can be met under natural air convection, thereby saving energy. The heat expansion medium in the expansion cylinder 653 is located at its bottom, and when the heat expansion medium moves the sliding lever 652 upward at a constant pressure, a sealed space is formed between the sliding lever 652 and the heat expansion cylinder 653, and the press switch 6531 will not be contacted.

[0044] As a specific embodiment of the present invention, refer to Figure 5 , Figure 6 and Figure 7The inclination control system 7 includes a transfer groove 71, a lifting platform 72 and an adjusting spring 73; the transfer groove 71 is opened at the lower part of the fan shaft 51; the lifting platform 72 is slidably sleeved on the fixed sliding rod 512; the adjusting spring 73 is connected between the lifting platform 72 and the fan blade 52. When the sliding lever 652 moves upward, the lifting platform 72 will move upward. When the lifting platform 72 is lifted, the inclination angle of the fan blade 52 will change. In order to reduce energy consumption under low-speed operation, the angle of the fan blade 52 is set to 30 degrees, which can enable the fan blade 52 to quickly increase the hot air flow in the cooling tower 2 in the axial direction of the wind direction, and at an angle of 30 degrees, the resistance encountered by the rotation of the fan blade 52 is small, so that the motor 61 bears less load at a low speed and saves more energy. When the angle of the fan blade 52 is 45 degrees, the contact area between the fan blade 52 and the air increases during the rotation process. The increased contact area helps to accelerate the process of heat conduction and convection, thereby improving the heat dissipation performance. The larger inclination angle makes the airflow more dispersed, thereby increasing the flow speed of air on and around the blade surface, and the air The faster the air flows, the more efficient the heat removal is, which is beneficial to heat dissipation. By guiding the airflow into more lateral and tangential flows, heat can be more effectively removed from the fan blades 52 and the area around the heat source. The fan blades 52 with an angle of 45 degrees to the horizontal plane will cause more airflow disturbances, which can make the air flow more uniform and reduce local airflow stagnation, thereby further improving the heat dissipation effect. Compared with an angle of 30 degrees, the resistance to the rotation of the fan blades 52 at an angle of 45 degrees will increase, causing the load of the circulating fan 5 to increase, so the angle of the fan blades 52 is only changed when the temperature exceeds the limit value; under the action of the adjusting spring 73, the fan blades 52 will be kept at 30 degrees when the lifting platform 72 does not slide upward to press the fan blades 52, thereby ensuring the axial flow guidance effect and smaller rotation resistance.

[0045] As a specific embodiment of the present invention, refer to Figure 6 and Figure 7The fan blade 52 includes a rotating blade 521 and a driving plate 522; the rotating blade 521 is installed in the rotating groove 511; the driving plate 522 is connected to the rotating blade 521 and is arranged inside the fan shaft 51, and a hemispherical groove 5221 is opened on the driving plate 522; the lifting platform 72 includes a sliding platform body 721 and a spherical push rod 722; the sliding platform body 721 is slidably installed on the fixed sliding rod 512; the spherical push rod 722 is connected to the upper end of the sliding platform body 721 and the ball at its upper end is located in the hemispherical groove 5221. The upward movement of the lifting platform 72 can make the rotating blades 521 rotate with the driving plate 522, thereby helping the circulating fan 5 to change the angle between the fan blades 52 and the horizontal plane. When the heat accumulated in the upper part of the cooling tower 2 is too high and the cooling water temperature in the packing layer 21 is high, the circulating fan 5 can change the angle of attack of the fan blades 52 while increasing the rotation speed, thereby helping the circulating fan 5 to enhance the heat dissipation capacity, so that under low-speed conditions, the blade inclination angle is smaller and the rotation resistance is smaller, which can further save energy. Under high-speed conditions, the inclination angle can be changed to further increase the heat dissipation speed, thereby avoiding increasing the rotation speed continuously without significantly improving the heat dissipation effect.

[0046] As a specific embodiment of the present invention, refer to Figure 7 and Figure 8 The inner wall diameter of the hemispherical groove 5221 is larger than the diameter of the sphere at the upper end of the spherical push rod 722, and when the angle between the rotating blade 521 and the horizontal plane is between 30 degrees and 45 degrees, the sphere at the upper end of the spherical push rod 722 is located inside the hemispherical groove 5221. Since the sphere diameter of the spherical push rod 722 is smaller than the diameter of the hemispherical groove 5221 on the driving plate 522, the spherical push rod 722 can slide in the hemispherical groove 5221 to avoid motion interference when the lifting platform 72 is lifted. At this time, the lifting platform 72 does not need to rotate during the lifting process, thereby ensuring that the circulating fan 5 rotates at high speed.

[0047] Working process: When the cooling water absorbs heat in the heat exchanger 3 and returns to the upper part of the cooling tower 2, it is sprayed into the packing layer 21. The heat expansion medium in the expansion cylinder 653 absorbs heat and expands. At this time, the sliding lever 652 slides upward. When the temperature is low, the circulating fan 5 will not be started. When the temperature rises to the set range, the sliding lever 652 will squeeze the pressing switch 6531 to turn on the circulating fan 5. When the temperature of the cooling water in the packing layer 21 is too high, the sliding lever 652, driven by the heat expansion medium, changes the speed of the output shaft 63 to a high gear, so that the speed of the circulating fan 5 increases. At the same time, the sliding lever 652 drives the inclination control system 7 to increase the angle between the fan blade 52 and the horizontal plane to 45 degrees, thereby improving the heat dissipation efficiency.

[0048] Specifically, the cooling water absorbs heat in the heat exchanger 3 and returns to the upper part of the cooling tower 2, where it is sprayed into the packing layer 21. The heat expansion medium in the expansion cylinder 653 in the packing layer 21 absorbs heat and expands. When the temperature of the cooling water in the packing layer 21 is low, the sliding lever 652 slides upward for a short distance, and the lower section of the sliding lever 652 does not contact the push switch 6531 at this time, so the circulating fan 5 is in the off state, and the cooling water is cooled by the natural airflow from the outside, thereby achieving the low-temperature energy-saving effect. If the cooling water in the packing layer 21 is in the air When the natural flow drops to a suitable range, the heat expansion medium returns to its original state; if the cooling water temperature is high, the heat expansion medium continues to expand and pushes the sliding lever 652 upward, and the lower section of the sliding lever 652 presses the pressure switch 6531 during the upward movement and keeps the pressure switch 6531 pressed. At this time, the motor 61 starts, and since the clutch sleeve 651 is connected to the low-speed gear in the speed gear set 64, the circulating fan 5 connected to the output shaft 63 will rotate at a low speed, and at this time the angle between the fan blade 52 and the horizontal plane is 30 degrees, and the circulating fan 5 The hot air is discharged from the cooling tower 2 in an axial flow manner, and the heat convection speed is accelerated to help the cooling water to dissipate heat quickly; when the cooling water temperature is too high and needs to be cooled quickly, the thermal expansion medium continues to expand and pushes the sliding lever 652 upward, and the sliding lever 652 drives the clutch sleeve 651 to move upward, and the clutch sleeve 651 will be connected to the high-speed gear in the speed change gear set 64. At this time, the output shaft 63 drives the circulating fan 5 to rotate at a high speed, thereby accelerating the heat dissipation speed; in order to further improve the heat dissipation efficiency and ensure that the accumulated heat can be dissipated in a short time, the sliding lever During the upward movement of 652, the lifting platform 72 will be pushed to move upward. At this time, the spherical push rod 722 pushes the driving plate 522, causing the driving plate 522 to flip. The driving plate 522 drives the rotating blade 521 to rotate, so that the angle between the rotating blade 521 and the horizontal plane increases from 30 degrees to 45 degrees, thereby increasing the contact area between the rotating blade 521 and the air during the rotation process, accelerating the process of heat conduction and convection, thereby improving the heat dissipation performance, and enabling the airflow to form a main axial flow and a supplementary radial flow, thereby quickly diffusing the airflow.

[0049] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected, and the scope of the present invention to be protected is defined by the attached claims and their equivalents.

Claims

1. A circulating fan control device for an air separation system, comprising a centrifugal compressor (1), a cooling tower (2), a heat exchanger (3) and a fractionating tower (4); characterized in that: The invention also comprises a circulating fan (5), a rotation speed control system (6) and an inclination control system (7); the circulating fan (5) comprises a fan shaft (51) and fan blades (52); the fan shaft (51) is arranged at the upper part of the cooling tower (2), and a rotating groove (511) is provided in a circumferential array on the side wall of the fan shaft (51); the fan blades (52) are installed in the rotating grooves (511); the rotation speed control system (6) is connected to the fan shaft (51), and the transmission ratio between the rotation speed control system (6) and the fan shaft (51) changes as the temperature rises or falls; the inclination control system (7) is connected to the fan blades (52), and the rotation speed control system (6) drives the inclination control system (7) to move up or down when the rotation speed control system (6) moves up or down, and when the inclination control system (7) moves up or down, it drives the fan blades (52) to rotate and increases or decreases the angle between the fan blades (52) and the horizontal plane.

2. The circulating fan control device of an air separation system according to claim 1, characterized in that: The speed control system (6) comprises a motor (61), an input shaft (62), an output shaft (63), a speed change gear set (64) and a speed change lever (65); the motor (61) is connected to the top of the cooling tower (2); the input shaft (62) is connected to the motor (61); the output shaft (63) is connected to the circulation fan (5); the speed change gear set (64) is connected between the input shaft (62) and the output shaft (63) in a meshing transmission manner; and the speed change lever (65) is connected to the output shaft (63).

3. The circulating fan control device of an air separation system according to claim 2, characterized in that: The shift lever (65) comprises a clutch sleeve (651), a sliding lever (652), an expansion cylinder (653) and a return spring (654); the clutch sleeve (651) is slidably mounted on the output shaft (63); the sliding lever (652) is connected to the clutch sleeve (651); a packing layer (21) is arranged in the middle of the cooling tower (2); the expansion cylinder (653) is arranged in the packing layer (21), and the expansion cylinder (653) is filled with a thermal expansion medium; the return spring (654) is connected between the expansion cylinder (653) and the sliding lever (652).

4. The circulating fan control device of an air separation system according to claim 2, characterized in that: The fan shaft (51) is hollow inside and has a fixed slide bar (512) at the center. A connecting block (513) is provided at the lower end of the fixed slide bar (512); the connecting block (513) is connected to the output shaft (63).

5. The circulating fan control device of an air separation system according to claim 3, characterized in that: A push switch (6531) is arranged in the middle of the expansion cylinder (653); the diameter of the upper section of the sliding lever (652) is smaller than the diameter of the lower section, and the diameter of the lower section is equal to the inner wall diameter of the expansion cylinder (653); the connection position between the upper section and the lower section of the sliding lever (652) is a conical structure transition; when the sliding lever (652) slides up and down, the upper section does not contact the push switch (6531).

6. The circulating fan control device of an air separation system according to claim 4, characterized in that: The inclination control system (7) comprises a switching groove (71), a lifting platform (72) and an adjusting spring (73); the switching groove (71) is arranged at the lower part of the fan shaft (51); the lifting platform (72) is slidably sleeved on the fixed sliding rod (512); and the adjusting spring (73) is connected between the lifting platform (72) and the fan blade (52).

7. The circulating fan control device of an air separation system according to claim 6, characterized in that: The fan blade (52) comprises a rotating blade (521) and a driving plate (522); the rotating blade (521) is installed in a rotating groove (511); the driving plate (522) is connected to the rotating blade (521) and is arranged inside the fan shaft (51), and a hemispherical groove (5221) is opened on the driving plate (522); the lifting platform (72) comprises a sliding platform body (721) and a spherical push rod (722); the sliding platform body (721) is slidably installed on the fixed sliding rod (512); the spherical push rod (722) is connected to the upper end of the sliding platform body (721) and the sphere at the upper end is located in the hemispherical groove (5221).

8. The circulating fan control device of an air separation system according to claim 7, characterized in that: The inner wall diameter of the hemispherical groove (5221) is larger than the diameter of the sphere at the upper end of the spherical push rod (722), and when the angle between the rotating blade (521) and the horizontal plane is between 30 degrees and 45 degrees, the sphere at the upper end of the spherical push rod (722) is located inside the hemispherical groove (5221).

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