Constant temperature leak-free seal device for chemical axial flow pump and method thereof

Abstract

The application discloses a constant-temperature leak-free sealing device for a chemical axial flow pump and a method thereof, and belongs to the technical field of chemical axial flow pumps, and solves the problem that the shaft sealing device of an existing axial flow pump is prone to sealing failure due to temperature change. The application shifts the dynamic sealing at the traditional secondary impeller to the outside by arranging a sealing cover and a sealing shell on the impeller shaft, thereby providing installation space for arranging a heat preservation component, facilitating maintenance, and through the arrangement of the heat preservation component in communication with a waste heat pipeline of an MVR system, the sealing cavity can be actively heat preserved by using the waste heat of the system itself, heating sources are saved, and excessive temperature fluctuation of the sealing cavity due to process heat conduction or environmental temperature change is avoided. In combination with a control component, real-time monitoring and accurate regulation of the temperature of the heat preservation cavity are realized, a closed-loop control system is formed, and therefore, the sealing cavity is ensured to be always in an optimal constant-temperature working state, and sealing failure caused by temperature fluctuation is avoided.

Description

Technical Field

[0001] This invention relates to the field of chemical axial flow pump technology, specifically to a constant temperature leak-free sealing device and method for axial flow pumps in MVR systems. Background Technology

[0002] As the core equipment in an MVR evaporation system, the evaporation circulation pump (axial flow pump) needs to operate stably for a long time under harsh conditions of high temperature and easy crystallization. Its shaft sealing system, as a key component of the axial flow pump, has the core requirement of ensuring leak-free delivery of the medium and constant temperature.

[0003] Currently, mechanical seals or packing seals are commonly used for the dynamic seals at the auxiliary impeller of axial flow pumps. Practice shows that mechanical seals, when dealing with high-temperature media, are prone to failure due to thermal shock or crystal buildup, leading to leakage. Packing seals, on the other hand, inevitably suffer from minor leakage, causing material waste and environmental pollution; furthermore, the wear of the packing material is exacerbated by fluctuations in the medium temperature.

[0004] Of particular concern is that existing sealing technologies lack an active temperature control mechanism, making it difficult to avoid excessively high or low local temperatures in the sealing cavity due to heat conduction from the process. This leads to accelerated aging of sealing elements in mechanical seals and crystallization of the medium in packing seals, ultimately resulting in premature seal failure. Summary of the Invention

[0005] To address the aforementioned shortcomings of the prior art, this invention provides a constant-temperature leak-free sealing device and method for axial flow pumps in MVR systems, which solves the problem that existing axial flow pump shaft sealing devices are prone to sealing failure due to temperature changes.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: On the one hand, a constant-temperature leak-free sealing device for chemical axial flow pumps is provided, comprising: The main body of the sealing device is located on the impeller shaft between the pump body and the bearing housing of the chemical axial flow pump, and includes a sealing shell and a sealing cover; one end of the sealing shell is installed on the pump body, and the sealing cover is fixed on the impeller shaft and dynamically sealed to the sealing shell; the sealing shell is provided with a secondary impeller chamber and a sealing cavity, the secondary impeller chamber is connected to the pump body and is provided with a secondary impeller fixed on the impeller shaft, and the sealing cavity is located between the sealing cover and the secondary impeller chamber; A thermal insulation component for maintaining a constant temperature in a sealed cavity includes a thermal insulation cavity disposed in a sealed shell. The thermal insulation cavity is located on the outer ring wall of the sealed cavity and is respectively connected to the waste heat energy inlet pipe and the waste heat energy outlet pipe of the MVR evaporation system. The control component, used to monitor and regulate the temperature inside the insulation cavity, includes a solenoid valve and a flow sensor installed on the waste heat energy inlet pipe, as well as temperature sensors installed in the waste heat energy inlet pipe, the sealing cavity, and the insulation cavity respectively; the solenoid valve, the flow sensor, and the three temperature sensors are all connected to the host computer for communication.

[0007] Furthermore, the insulation cavity includes a first insulation cavity and a second insulation cavity respectively disposed in the sealing cavity and the outer ring of the auxiliary impeller. The outer ring wall of the first insulation cavity is connected to the waste heat energy inlet pipe and the waste heat energy outlet pipe, respectively. The second insulation cavity has an annular hole on its end face near the first insulation cavity for communicating with the first insulation cavity, and a temperature sensor is installed inside the second insulation cavity.

[0008] Furthermore, the sealing cover is dynamically sealed to the sealing shell through a packing seal, mechanical seal, or sealing ring; the sealing ring includes a V-shaped sealing ring disposed on the sealing cover and an annular spring disposed in the sealing cavity, the annular spring being extruded and connected to the V-shaped sealing ring.

[0009] Furthermore, the inner ring of the sealing cover is fixed to the bushing, and the bushing is fixed to the impeller shaft by a pin. A sealing ring is provided between the inner ring surface of the bushing and the outer ring surface of the impeller shaft. An abutting bushing is provided on the outer ring surface of the bushing, and the two ends of the abutting bushing abut against the sealing cover and the auxiliary impeller, respectively.

[0010] On the other hand, a method for providing a temperature-controlled, leak-free sealing device for a chemical axial flow pump includes the following steps: S1. Determine the target operating conditions of the chemical axial flow pump based on the operating characteristics of the MVR evaporation system, and obtain the constant temperature required for the sealing cavity under the target operating conditions. S2. Collect the temperature of the medium transported in the insulation cavity, sealing cavity, and waste heat energy inlet pipe. Based on the collected temperature data, use the sliding diaphragm controller in the host computer to adjust the opening of the solenoid valve on the waste heat energy inlet pipe so that the temperature of the insulation cavity is consistent with the constant temperature of the target working condition.

[0011] Furthermore, the expression for the host computer to adjust the opening degree of the solenoid valve is:

[0012] , ,

[0013] in, This refers to the opening degree of the solenoid valve. The heat capacity within the insulation cavity; This refers to the heat input coefficient. Valve coefficient; and These represent the temperature and specific heat capacity of the conveying medium, respectively. , and These are the temperatures of the sealed cavity, the insulation cavity, and the conveying medium, respectively. This is the heat loss coefficient; and These are the heat transfer coefficient and heat transfer area between the insulation cavity and the sealing cavity, respectively; For the current moment Temperature error; , , , These are all control parameters for the slid controller, namely, slid area integral parameters, control gain, slid surface, and boundary layer thickness; It is a saturation function; It is a symbolic function; From historical moment 0 to the current moment Temperature cumulative error term, For a historic moment Temperature error.

[0014] Furthermore, the synovial area integral parameter is a control parameter in the synovial controller. Control gain and boundary layer thickness The calculation method is as follows: S21. Predefined typical operating conditions for chemical axial flow pumps. Each typical operating condition is divided according to the equipment's thermal load intensity and the level of disturbance in the working environment. Each typical operating condition is preset with corresponding sliding film area integral parameters, initial values ​​of control gain, and preset values ​​of boundary layer thickness.

[0015] S22. Determine the typical working condition corresponding to the target working condition based on the equipment heat load intensity and the disturbance level of the working environment, and obtain the initial values ​​of the sliding surface integral parameters and control gain corresponding to the target working condition, as well as the preset value of the boundary layer thickness.

[0016] S23. The synovial area integral parameter and control gain in the control parameters are optimized using the whale optimization algorithm. The optimized synovial area integral parameter and control gain, as well as the preset value of the boundary layer thickness, are used as the final control parameters.

[0017] Furthermore, the optimization method for the synovial area integral parameter and control gain is as follows: S231. Using the initial values ​​of the synovial surface area integral parameter and the control gain as a set of optimal whale positions, and randomly generating multiple sets of whale positions within the range of the synovial surface area integral parameter and the control gain, set the whale parameters for the whale optimization algorithm. The whale parameters include the maximum number of iterations. Number of iterations Convergence coefficient a, spiral shape constant b, first global coefficient A, and second global coefficient C S232, Order And update a, A, and C: , , ; in, and A random vector between [0,1]; S233. Generate a random probability p, and update the positions of all whales based on the absolute value of A and p; S234. Calculate the fitness function for each group of whale locations. , ; S235. Repeat steps S232 to S234 until completion. The maximum number of iterations is used to obtain the whale position corresponding to the minimum fitness function. The synovial area integral parameters and control gain corresponding to this whale position are the optimized synovial area integral parameters and control gain.

[0018] Furthermore, methods for updating whale locations include: Determine if the random probability p is greater than 0.5. If so, perform a spiral update simulation. , , Otherwise, continue judging. If the value is less than 1, then perform a bubble web attack update: , Otherwise, update by surrounding the prey: , ; in, and These are the optimal whale position and the position of the i-th group of whales, respectively. and , respectively, are the initial values ​​of the synovial surface integral parameter and the control gain; l is a random number in [-1,1]; , and Both are the distances between the locations of the two whales; for The update location; This represents a random set of whale locations.

[0019] Furthermore, methods for updating whale locations also include: The position update for each group of whale locations is constrained, and the expression for the constraint is:

[0020] in, and They are respectively The synovial area integral parameters and control gain in the model; and These are the minimum and maximum values ​​of the synovial area integral parameter; and This controls the minimum and maximum values ​​of the gain.

[0021] Compared with the prior art, the present invention has the following significant advantages: 1. This invention, by installing a sealing cover and a sealing shell on the impeller shaft, transfers the dynamic seal from the traditional secondary impeller to the outside. This not only provides installation space for the insulation component and facilitates maintenance, but also, by installing the insulation component connected to the waste heat pipeline of the MVR system, it can actively insulate the sealing cavity using the system's own waste heat, saving the heating source and avoiding excessive temperature fluctuations in the sealing cavity due to process heat conduction or changes in ambient temperature. Combined with the control component, it achieves real-time monitoring and precise adjustment of the insulation cavity temperature, forming a closed-loop control system. This ensures that the sealing cavity is always in an optimal constant temperature operating state, fundamentally avoiding problems such as medium crystallization or aging of sealing elements caused by temperature fluctuations. It significantly improves the service life and reliability of the sealing device under harsh operating conditions and solves the problem that the shaft seal device of existing axial flow pumps is prone to seal failure due to temperature changes.

[0022] 2. The present invention specifically divides the insulation chamber into a first insulation chamber and a second insulation chamber, and places the temperature sensor in the second insulation chamber. The environment of the second insulation chamber is stable, which avoids the temperature sensor being directly washed by the waste hot water or waste steam of the waste heat pipe of the MVR system, making the collected temperature data more stable and facilitating the host computer to adjust the temperature more accurately.

[0023] 3. In addition to using packing seals or mechanical seals for the dynamic seal between the sealing cover and the sealing shell, this invention also proposes a sealing ring component scheme that includes a V-shaped sealing ring and an annular spring piece. This is because the rotation of the auxiliary impeller can push the medium in the pump body in the reverse direction, effectively blocking the leakage path of the medium along the axial or radial direction. Furthermore, considering the increased installation space between the sealing cover and the sealing shell, a sealing ring component scheme is specifically proposed. The medium pressure in the sealing cavity pushes the annular spring piece to press the V-shaped sealing ring, achieving a sealing effect similar to that of a packing seal. At the same time, the annular spring piece provides continuous pressing force and can compensate for the wear of the sealing ring. This not only results in a low structural cost but also extends the life of the V-shaped sealing ring when combined with the insulation component, further reducing sealing costs. 4. Through the structural design of the bushing and the abutting bushing, the present invention axially positions and fixes the sealing cover and the auxiliary impeller, ensuring the relative positional accuracy between the transmission components (sealing cover, auxiliary impeller) and the stationary components (sealing shell), so that the dynamic sealing connection can work stably and uniformly, avoiding uneven sealing or wear caused by axial movement, and improving the stability and mechanical reliability of the entire device.

[0024] 5. The control component of this invention dynamically adjusts the valve opening through a sliding diaphragm controller. Its unique sliding diaphragm surface design and application of saturation functions enable the system to be highly robust to model uncertainties and external disturbances. Compared with traditional PID control, this controller can effectively overcome the nonlinear characteristics of the system and can quickly and stably maintain the set temperature when the temperature and flow rate of the insulation medium change, avoiding overshoot and continuous oscillation, and ensuring the stability of the shaft sealing system.

[0025] 6. This invention applies the whale optimization algorithm to the automatic tuning of sliding diaphragm control parameters. By defining the fitness function IAE as the optimization objective of the performance index and simulating three search behaviors—whale encirclement of prey, bubble net attack, and spiral update—the algorithm can globally optimize under multiple operating conditions, finding the parameter combination that optimizes the dynamic performance of the control system. This solves the technical bottleneck of traditional methods that rely on empirical trial and error and are difficult to obtain the best control effect.

[0026] 7. This invention pre-sets multiple typical working condition models. The host computer can automatically identify and match the corresponding working conditions based on the current pumping medium temperature, the inlet flow rate and temperature of the insulation cavity. For different working condition characteristics, the system calls the exclusive control parameters pre-optimized by the whale algorithm and quickly calls the control parameters close to the optimal ones, which shortens the time for the system to adjust to a stable state and reduces the temperature shock time. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the connection structure between the constant temperature leak-free sealing device and the pump body.

[0028] Figure 2 A schematic diagram of a constant-temperature, leak-free sealing device; Figure 3 This is a schematic diagram of the structure of the sealing shell and the sealing cover; Figure 4 for Figure 3 A magnified view of a section at point A in the middle; Figure 5 This is a schematic diagram showing the connection between the bushing and the impeller shaft; Figure 6 A structural block diagram of a method for a constant-temperature, leak-free sealing device; The components include: 1. Main body of the device; 2. Pump body; 3. Bearing housing; 4. Impeller shaft; 5. Sealing shell; 6. Sealing cover; 7. Secondary impeller chamber; 8. Sealing cavity; 9. Secondary impeller; 10. First insulation cavity; 11. Second insulation cavity; 12. V-shaped sealing ring; 13. Annular spring piece; 14. Shaft sleeve; 15. Abutting shaft sleeve; 16. Limiting block. Detailed Implementation

[0029] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0030] Example 1

[0031] This embodiment provides a constant temperature and leak-free sealing device for chemical axial flow pumps, including a sealing device body 1, a heat insulation component, and a control component.

[0032] refer to Figure 1 and Figure 2 The main body 1 of the sealing device is installed on the impeller shaft 4 located between the pump body 2 and the bearing housing 3 of the chemical axial flow pump, and includes a sealing shell 5 and a sealing cover 6. One end of the sealing shell 5 is installed on the pump body 2, and the sealing cover 6 is fixed on the impeller shaft 4 and dynamically sealed to the sealing shell 5. The sealing shell 5 is provided with a secondary impeller chamber 7 and a sealing cavity 8. The secondary impeller chamber 7 is connected to the pump body 2 and has a secondary impeller 9 fixed on the impeller shaft 4 inside. The sealing cavity 8 is located between the sealing cover 6 and the secondary impeller chamber 7.

[0033] The insulation component is used to maintain a constant temperature in the sealed cavity 8. It includes an insulation cavity disposed in the sealed shell 5. The insulation cavity is located on the outer ring wall of the sealed cavity 8 and is respectively connected to the waste heat energy inlet pipe and the waste heat energy outlet pipe of the MVR evaporation system. The control component monitors and regulates the temperature within the insulation chamber. It includes a solenoid valve and flow sensor mounted on the waste heat energy inlet pipe, as well as temperature sensors located in the waste heat energy inlet pipe, the sealed chamber 8, and the insulation chamber. The solenoid valve, flow sensor, and three temperature sensors are all connected to a host computer. A pressure sensor, also connected to the host computer, is also mounted on the waste heat energy inlet pipe. The host computer contains a sliding diaphragm controller. The flow and pressure sensors facilitate the monitoring of the flow rate and pressure of the medium transported through the waste heat energy inlet pipe.

[0034] Specifically, the insulation cavity includes a first insulation cavity 10 and a second insulation cavity 11 respectively disposed on the outer ring of the sealing cavity 8 and the auxiliary impeller chamber 7; the outer ring wall of the first insulation cavity 10 is connected to the waste heat energy inlet pipe and the waste heat energy outlet pipe respectively; the end face of the second insulation cavity 11 near the first insulation cavity 10 is provided with an annular hole for communicating with the first insulation cavity 10, and a temperature sensor is disposed inside the second insulation cavity 11.

[0035] The insulation chamber is specifically divided into a first insulation chamber 10 and a second insulation chamber 11. The temperature sensor is placed in the second insulation chamber 11. The environment of the second insulation chamber 11 is stable, which avoids the temperature sensor being directly washed by the waste hot water or waste steam of the waste heat pipe of the MVR system, making the collected temperature data more stable and facilitating the host computer to adjust the temperature more accurately.

[0036] In this embodiment, the sealing cap 6 is dynamically sealed to the sealing shell 5 via a packing seal, mechanical seal, or sealing ring. Referring to Figures 3 and 4... Figure 4 The sealing ring component includes a V-shaped sealing ring 12 disposed on the sealing cover 6 and an annular spring piece 13 disposed in the sealing cavity 8, and the annular spring piece 13 is pressed and connected to the V-shaped sealing ring 12.

[0037] refer to Figure 5 The inner ring of the sealing cover 6 is fixed on the bushing 14, and the bushing 14 is fixed on the impeller shaft 4 by a pin. A sealing ring is provided between the inner ring surface of the bushing 14 and the outer ring surface of the impeller shaft 4. An abutting bushing 15 is provided on the outer ring surface of the bushing 14, and the two ends of the abutting bushing 15 abut against the sealing cover 6 and the auxiliary impeller 9, respectively.

[0038] A ring-shaped limiting block 16 is detachably provided on the outer ring end of the sealing cover 6. The limiting block 16 is used to limit the sealing shell 5 for easy installation. As a further embodiment, a wiring hole is opened on the limiting block 16. The power supply and signal harness of the temperature sensor located in the sealing cavity 8 are connected out through the wiring hole through the gap between the spring piece and the sealing ring. Since the ring spring piece 13 and the V-shaped sealing ring 12 are elastically matched, a certain sealing effect can be achieved when there is passage. At the same time, when the machine stops, the auxiliary impeller 9 seal does not work, and the pressure in the cavity increases, causing the elastic piece to press the sealing ring tightly, ensuring the sealing effect in the static stop state.

[0039] This embodiment, by setting a sealing cover 6 and a sealing shell 5 on the impeller shaft 4, transfers the dynamic seal of the traditional auxiliary impeller 9 to the outside. This not only provides installation space for the insulation component but also facilitates maintenance. Furthermore, by setting an insulation component connected to the waste heat pipeline of the MVR system, the system's own waste heat can be used to actively insulate the sealing cavity 8, saving on the heating source and preventing excessive temperature fluctuations in the sealing cavity 8 due to process heat conduction or changes in ambient temperature. Combined with the control component, real-time monitoring and precise adjustment of the insulation cavity temperature are achieved, forming a closed-loop control system. This ensures that the sealing cavity 8 is always in an optimal constant-temperature operating state, fundamentally avoiding problems such as medium crystallization or aging of sealing elements caused by temperature fluctuations.

[0040] Example 2

[0041] refer to Figure 6 This embodiment is a further limitation based on Embodiment 1, and its purpose is to provide a method for a constant temperature leak-free sealing device for a chemical axial flow pump, including the following steps: S1. Determine the target operating conditions of the chemical axial flow pump based on the operating characteristics of the MVR evaporation system, and obtain the constant temperature required for the sealing cavity under the target operating conditions.

[0042] S2. Collect the temperature of the medium transported in the insulation cavity, sealing cavity, and waste heat energy inlet pipe. Based on the collected temperature data, use the sliding diaphragm controller in the host computer to adjust the opening of the solenoid valve on the waste heat energy inlet pipe so that the temperature of the insulation cavity is consistent with the constant temperature of the target working condition.

[0043] Specifically, the expression for adjusting the opening degree of the solenoid valve by the host computer is as follows:

[0044] , ,

[0045] in, This refers to the opening degree of the solenoid valve. The heat capacity within the insulation cavity; This refers to the heat input coefficient. Valve coefficient; and These represent the temperature and specific heat capacity of the conveying medium, respectively. , and These are the temperatures of the sealed cavity, the insulation cavity, and the conveying medium, respectively. This is the heat loss coefficient; and These are the heat transfer coefficient and heat transfer area between the insulation cavity and the sealing cavity, respectively; For the current moment Temperature error in the middle, i.e. The difference between the constant temperature and the target operating condition; , , , These are all control parameters for the slid controller, namely, slid area integral parameters, control gain, slid surface, and boundary layer thickness; It is a saturation function; It is a symbolic function; From historical moment 0 to the current moment Temperature cumulative error term, For a historic moment Temperature error, historical moment The range is 0 to t.

[0046] For ease of understanding, the derivation process of the expression for adjusting the opening degree of the solenoid valve by the host computer is as follows: Heat input for: , ;in, This refers to the flow rate of the waste heat energy inlet pipe.

[0047] Heat loss for: .

[0048] Therefore, the energy balance equation for the insulation cavity is: The transformation yields: ,in , .

[0049] According to the slippery surface The surface derivative of the synovial membrane is obtained. Substitute get: .

[0050] To satisfy Lyapunov stability theory and reduce system chattering, the following formula is designed: , Substituting the values, we obtain the expression for calculating the opening degree of the solenoid valve:

[0051] As a further embodiment, the synovial area integral parameter is included in the control parameters of the synovial controller. Control gain and boundary layer thickness The calculation method is as follows: S21. Predefined typical operating conditions for chemical axial flow pumps. Each typical operating condition is divided according to the equipment's thermal load intensity and the level of disturbance in the working environment. Each typical operating condition is preset with corresponding sliding film area integral parameters, initial values ​​of control gain, and preset values ​​of boundary layer thickness.

[0052] S22. Determine the typical working condition corresponding to the target working condition based on the equipment heat load intensity and the disturbance level of the working environment, and obtain the initial values ​​of the sliding surface integral parameters and control gain corresponding to the target working condition, as well as the preset value of the boundary layer thickness.

[0053] S23. The synovial area integral parameter and control gain in the control parameters are optimized using the whale optimization algorithm. The optimized synovial area integral parameter and control gain, as well as the preset value of the boundary layer thickness, are used as the final control parameters.

[0054] In this embodiment, six typical operating conditions are predefined. Each operating condition is divided according to different combinations of heat load intensity and environmental disturbance level. The above parameters are related to the pumping medium temperature, the inlet flow rate of the insulation cavity and the inlet temperature. Tests are conducted on each operating condition to determine its corresponding initial control parameters, so that the sliding diaphragm controller can better adapt to dynamic environmental changes and achieve an adaptive effect for different operating conditions.

[0055] Among them, the equipment heat load intensity H: V is the volume of the insulation cavity.

[0056] The heat load intensity H reflects the amount of heat that the system needs to compensate. Under low heat loads, the system response is smooth, and control should focus on energy saving and stability; under high heat loads, the system needs a rapid response, and control should prioritize performance. Heat load intensity is judged by classifying low heat load level H (low) and high heat load level H (high) according to the heat load intensity threshold.

[0057] Operating environment disturbance level D: .

[0058] The environmental disturbance level D1 is set according to the working environment disturbance level threshold to judge the working environment disturbance. The rate of change of ambient temperature D reflects the intensity of the disturbance of the external environment to the insulation cavity. The environment is stable under low disturbance, while the environment changes drastically under high disturbance, and the controller needs to have stronger anti-interference capability. See Table 1 for details.

[0059]

[0060] , If H<H(low) and D<D1, it indicates that the environment is stable with low heat demand and the system operates stably. The control target should be mainly energy saving. Therefore, a small λ is required to reduce the convergence rate, a small K is required to reduce the control gain, and a large φ is required to reduce chattering, so as to realize smooth energy-saving control; if H(low)<H<H(high) and D<D1, it indicates that the environment is stable with moderate heat demand, and a balance between energy saving and response is required. Therefore, a moderate λ is required to ensure the convergence rate, a moderate K is required to provide necessary control force, so as to balance performance and energy consumption; if H>H(high) and D<D1, it indicates that the environment is stable with high heat demand, and rapid response and high-performance control are required. Therefore, a large λ is required to accelerate error convergence, a large K is required to enhance control force, and a small φ is required to improve control accuracy, so as to meet high-load demands. The set values for the remaining conditions are set according to the above method, refer to Table 2.

[0061]

[0062] Before the device is used, the working condition characteristics are judged according to the information collected by the sensor, and the corresponding initial control parameters are selected according to the approaching working condition , initial values λ_base and K_base, and the preset value of φ.

[0063] Specifically, the optimization method for sliding mode integration parameters and control gain is: S231, taking the initial values of the sliding mode integration parameters and control gain as a set of optimal whale positions, randomly generating multiple sets of whale positions within the range of the sliding mode integration parameters and control gain, and setting the whale parameters of the whale optimization algorithm, wherein the whale parameters include the maximum number of iterations , the number of iterations , convergence coefficient a, spiral shape constant b, first global coefficient A and second global coefficient C S232, let , and update a, A and C: , , ; wherein, and are random vectors between [0,1]; S233, generating a random probability p, updating all whale positions according to the absolute value of A and p; S234, calculating the fitness function of each set of whale positions , ; S235, repeating steps S232 to S234 until completing The maximum number of iterations is used to obtain the whale position corresponding to the minimum fitness function. The synovial area integral parameters and control gain corresponding to this whale position are the optimized synovial area integral parameters and control gain.

[0064] As a further embodiment, the method for updating the whale's location includes: Determine if the random probability p is greater than 0.5. If so, perform a spiral update simulation. , , Otherwise, continue judging. If the value is less than 1, then perform a bubble web attack update: , Otherwise, update by surrounding the prey: , ; in, and These are the optimal whale position and the position of the i-th group of whales, respectively. and , respectively, are the initial values ​​of the synovial surface integral parameter and the control gain; l is a random number in [-1,1]; , and Both are the distances between the locations of the two whales; for The update location; This represents a random set of whale locations.

[0065] In this implementation, constraints need to be applied to the updated positions of each group of whale locations. The expression for the constraints is as follows:

[0066] in, and They are respectively The synovial area integral parameters and control gain in the model; and These are the minimum and maximum values ​​of the synovial area integral parameter; and This controls the minimum and maximum values ​​of the gain.

[0067] In summary, this embodiment applies the whale optimization algorithm to the automatic tuning of slicker control parameters. By defining the fitness function IAE as the optimization objective for performance indicators and simulating three search behaviors—whale encirclement of prey, bubble net attack, and spiral update—the algorithm can globally optimize under multiple operating conditions to find the parameter combination that optimizes the dynamic performance of the control system.

Claims

1. A constant-temperature, leak-free sealing device for chemical axial flow pumps, characterized in that, include: The sealing device body (1) is set on the impeller shaft (4) between the pump body (2) and the bearing housing (3) of the chemical axial flow pump, and includes a sealing shell (5) and a sealing cover (6); one end of the sealing shell (5) is installed on the pump body (2), and the sealing cover (6) is fixed on the impeller shaft (4) and dynamically sealed to the sealing shell (5); the sealing shell (5) is provided with a secondary impeller chamber (7) and a sealing cavity (8), the secondary impeller chamber (7) is connected to the pump body (2) and is provided with a secondary impeller (9) fixed on the impeller shaft (4) inside, and the sealing cavity (8) is located between the sealing cover (6) and the secondary impeller chamber (7); The heat insulation component is used to maintain the constant temperature of the sealed cavity (8), which includes a heat insulation cavity disposed in the sealed shell (5), the heat insulation cavity being located on the outer ring wall of the sealed cavity (8) and connected to the waste heat energy inlet pipe and waste heat energy outlet pipe of the MVR evaporation system respectively; The control component is used to monitor and regulate the temperature inside the insulation cavity. It includes a solenoid valve and a flow sensor installed on the waste heat energy inlet pipe, and temperature sensors installed in the waste heat energy inlet pipe, the sealed cavity (8), and the insulation cavity, respectively. The solenoid valve, the flow sensor, and the three temperature sensors are all connected to the host computer for communication.

2. The constant temperature leak-free sealing device for chemical axial flow pumps according to claim 1, characterized in that, The insulation cavity includes a first insulation cavity (10) and a second insulation cavity (11) respectively disposed on the outer ring of the sealing cavity (8) and the auxiliary impeller chamber (7); The outer ring wall of the first heat insulation cavity (10) is connected to the waste heat energy inlet pipe and the waste heat energy outlet pipe respectively; The second heat insulation cavity (11) has an annular hole on its end face near the first heat insulation cavity (10) for communicating with the first heat insulation cavity (10), and a temperature sensor is provided inside the second heat insulation cavity (11).

3. The constant-temperature leak-free sealing device for chemical axial flow pumps according to claim 1, characterized in that, The sealing cover (6) is dynamically sealed to the sealing shell (5) by a packing seal, mechanical seal or sealing ring; the sealing ring includes a V-shaped sealing ring (12) disposed on the sealing cover (6) and an annular spring piece (13) disposed in the sealing cavity (8), and the annular spring piece (13) is squeezed to the V-shaped sealing ring (12).

4. The constant temperature leak-free sealing device for chemical axial flow pumps according to claim 1, characterized in that, The inner ring of the sealing cover (6) is fixed on the bushing (14), and the bushing (14) is fixed on the impeller shaft (4) by a pin. A sealing ring is provided between the inner ring surface of the bushing (14) and the outer ring surface of the impeller shaft (4). An abutting bushing (15) is provided on the outer ring surface of the bushing (14), and the two ends of the abutting bushing (15) abut against the sealing cover (6) and the auxiliary impeller (9) respectively.

5. The method for a constant-temperature leak-free sealing device for a chemical axial flow pump according to any one of claims 1 to 4, characterized in that, Including the following steps: S1. Determine the target operating conditions of the chemical axial flow pump based on the operating characteristics of the MVR evaporation system, and obtain the constant temperature required for the sealing cavity under the target operating conditions. S2. Collect the temperature of the medium transported in the insulation cavity, sealing cavity, and waste heat energy inlet pipe. Based on the collected temperature data, use the sliding diaphragm controller in the host computer to adjust the opening of the solenoid valve on the waste heat energy inlet pipe so that the temperature of the insulation cavity is consistent with the constant temperature of the target working condition.

6. The constant-temperature leak-free sealing device and method for chemical axial flow pumps according to claim 5, characterized in that, The expression for adjusting the opening degree of the solenoid valve by the host computer is: ， ， in, This refers to the opening degree of the solenoid valve. The heat capacity within the insulation cavity; This refers to the heat input coefficient. Valve coefficient; and These represent the temperature and specific heat capacity of the conveying medium, respectively. , and These are the temperatures of the sealed cavity, the insulation cavity, and the conveying medium, respectively. This is the heat loss coefficient; and These are the heat transfer coefficient and heat transfer area between the insulation cavity and the sealing cavity, respectively; For the current moment Temperature error; , , , These are all control parameters for the slid controller, namely, slid area integral parameters, control gain, slid surface, and boundary layer thickness; It is a saturation function; It is a symbolic function; From historical moment 0 to the current moment Temperature cumulative error term, For a historic moment Temperature error.

7. The method for a constant-temperature leak-free sealing device for a chemical axial flow pump according to claim 6, characterized in that, The synovial area integral parameter in the control parameters of the synovial controller Control gain and boundary layer thickness The calculation method is as follows: S21. Predefined typical operating conditions of chemical axial flow pumps. Each typical operating condition is divided according to the heat load intensity of the equipment and the disturbance level of the working environment. Each typical operating condition is preset with corresponding sliding film area integral parameters, initial values ​​of control gain and preset values ​​of boundary layer thickness. S22. Determine the typical working condition corresponding to the target working condition based on the equipment heat load intensity and working environment disturbance level, and obtain the initial values ​​of the sliding film area integral parameters and control gain corresponding to the target working condition, as well as the preset value of the boundary layer thickness. S23. The synovial area integral parameter and control gain in the control parameters are optimized using the whale optimization algorithm. The optimized synovial area integral parameter and control gain, as well as the preset value of the boundary layer thickness, are used as the final control parameters.

8. The method for a constant-temperature leak-free sealing device for a chemical axial flow pump according to claim 7, characterized in that, The optimization methods for the synovial area integral parameters and control gain are as follows: S231. Using the initial values ​​of the synovial surface area integral parameter and the control gain as a set of optimal whale positions, and randomly generating multiple sets of whale positions within the range of the synovial surface area integral parameter and the control gain, set the whale parameters for the whale optimization algorithm. The whale parameters include the maximum number of iterations. Number of iterations Convergence coefficient a, spiral shape constant b, first global coefficient A, and second global coefficient C S232, Order And update a, A, and C: ， ， ； in, and A random vector between [0,1]; S233. Generate a random probability p, and update the positions of all whales based on the absolute value of A and p; S234. Calculate the fitness function for each group of whale locations. , ; S235. Repeat steps S232 to S234 until completion. The maximum number of iterations is used to obtain the whale position corresponding to the minimum fitness function. The synovial area integral parameters and control gain corresponding to this whale position are the optimized synovial area integral parameters and control gain.

9. The method for a constant-temperature leak-free sealing device for a chemical axial flow pump according to claim 8, characterized in that, Methods for updating whale locations include: Determine if the random probability p is greater than 0.

5. If so, perform a spiral update simulation. ， ， Otherwise, continue judging. If the value is less than 1, then perform a bubble web attack update: ， Otherwise, update by surrounding the prey: , ; in, and These are the optimal whale position and the position of the i-th group of whales, respectively. and , respectively, are the initial values ​​of the synovial surface integral parameter and the control gain; l is a random number in [-1,1]; , and Both are the distances between the locations of the two whales; for The update location; This represents a random set of whale locations.

10. The method for a constant-temperature leak-free sealing device for a chemical axial flow pump according to claim 9, characterized in that, Other methods for updating whale locations include: The position update for each group of whale locations is constrained, and the expression for the constraint is: in, and They are respectively The synovial area integral parameters and control gain in the model; and These are the minimum and maximum values ​​of the synovial area integral parameter; and This controls the minimum and maximum values ​​of the gain.

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