An auxiliary system of single end face mechanical seal with dry friction prevention function

Abstract

The application discloses an auxiliary system of single-end-face mechanical seal with anti-dry friction function, and belongs to the technical field of mechanical seal. The auxiliary system comprises a base and a support arranged on the base. A storage lubricating liquid tank is arranged on the support. The storage lubricating liquid tank stores lubricating liquid. The top of the storage lubricating liquid tank is a cavity, and the cavity is filled with gas. The storage lubricating liquid tank is connected with a liquid supplement pipe and an exhaust pipe. One end of the liquid supplement pipe is below the liquid level of the lubricating liquid in the storage lubricating liquid tank, and the other end of the liquid supplement pipe is used for being connected with a pump. One end of the exhaust pipe is connected with the pump, and the other end of the exhaust pipe is communicated with the cavity of the storage lubricating liquid tank. A liquid supplement valve is arranged on the liquid supplement pipe, and a one-way valve is arranged on the exhaust pipe. The application can realize automatic supply of lubricating liquid, real-time state monitoring, self-adaptive control and fault diagnosis, effectively avoids the dry friction phenomenon of mechanical seal, and improves the stability and reliability of system operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical seal, in particular to an auxiliary system for single-end-face mechanical seal. BACKGROUND

[0002] In the operation process of the pump body equipment, the single-end-face mechanical seal is a key component for preventing the leakage of the medium in the pump, which mainly relies on the close adhesion between the dynamic ring and the static ring to form a sealing surface. However, at the initial stage of the pump body start-up, there is often a lack of sufficient lubricating liquid between the dynamic ring and the static ring, which is prone to dry friction phenomenon. Meanwhile, during the operation process of the pump body, if the supply of lubricating liquid is insufficient or interrupted, it will also cause dry friction of the sealing surface, resulting in wear of the dynamic ring and the static ring, decline of the sealing performance, and even cause the pump body to stop running, increase the equipment maintenance cost and production loss.

[0003] At present, the existing lubricating auxiliary device for single-end-face mechanical seal mostly adopts manual liquid supplementing mode, which requires the operator to frequently check and supplement the lubricating liquid before the pump body start-up and during the operation process, and the operation is complicated and the reliability is low, so it is difficult to realize the precise and automatic supply of the lubricating liquid. In addition, the existing auxiliary device lacks real-time monitoring and fault diagnosis function for the lubricating liquid supply state, system pressure, temperature and other parameters, cannot timely find the faults such as lubricating liquid leakage and pipeline blockage, and cannot adaptively adjust the lubricating liquid flow according to the change of system working condition, resulting in unstable lubricating effect and still existing risk of dry friction. SUMMARY

[0004] The purpose of the present application is to provide an auxiliary system for single-end-face mechanical seal with dry friction prevention function, which can realize automatic supply, real-time state monitoring, adaptive control and fault diagnosis of the lubricating liquid, effectively avoid the dry friction phenomenon of the mechanical seal, and improve the stability and reliability of the system operation.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] An auxiliary system for single-end-face mechanical seal with dry friction prevention function, comprising a base and a support arranged on the base, a lubricating liquid storage tank is arranged on the support, the lubricating liquid storage tank stores lubricating liquid inside, the top of the lubricating liquid storage tank is a cavity, and the cavity is filled with gas;

[0007] The lubricating liquid storage tank is connected with a liquid supplementing pipe and an exhaust pipe, one end of the liquid supplementing pipe is located below the liquid level of the lubricating liquid in the lubricating liquid storage tank, and the other end is used for connecting with the pump; one end of the exhaust pipe is connected with the pump, and the other end is in communication with the cavity of the lubricating liquid storage tank; a liquid supplementing valve is arranged on the liquid supplementing pipe, and a one-way valve is arranged on the exhaust pipe;

[0008] In use, the lubricating liquid is filled into the lubricating liquid storage tank, which forms the cavity in the upper part of the lubricating liquid storage tank, and the replenishment valve is opened before the pump works, so that the lubricating liquid is automatically injected into the mechanical seal of the pump through the replenishment pipe.

[0009] When the pump works, the medium generates pressure and enters the lubricating liquid storage tank through the replenishment pipe, and the air in the cavity in the upper part of the lubricating liquid storage tank is compressed, and the replenishment valve is closed after the pump stops working; when working next time, the valve is opened, and the medium and the lubricating liquid automatically enter the mechanical seal of the pump due to the high air pressure in the cavity of the lubricating liquid storage tank, so as to realize lubrication.

[0010] Further, the replenishment valve is a manual valve or an electromagnetic valve.

[0011] Further, the auxiliary system further comprises a controller and a plurality of sensors, the plurality of sensors comprising a liquid level sensor for detecting the liquid level of the lubricating liquid storage tank, a first pressure sensor for detecting the pressure of the lubricating liquid storage tank, a second pressure sensor for detecting the pressure of the sealing cavity of the pump, and a temperature sensor.

[0012] The signal input end of the controller is electrically connected with the signal output end of the plurality of sensors, and the control output end of the controller is electrically connected with the control end of the replenishment valve.

[0013] The controller is configured as follows:

[0014] The state monitoring and diagnosis process: reading the measurement values of the plurality of sensors, calculating the real-time flow, the system pressure difference and the fault diagnosis flag;

[0015] The adaptive control process: receiving the output results of the state monitoring and diagnosis process, if the diagnosis flag is normal, calculating and outputting the control signal to the replenishment valve according to the system pressure difference and the temperature sensor reading through the pre-stored control algorithm; if the diagnosis flag is abnormal, outputting the control signal to close the replenishment valve.

[0016] Further, the calculation of the real-time flow in the state monitoring and diagnosis process is specifically: according to the difference between the liquid level sensor readings at the current time and the last time, and combining the cross-sectional area of the lubricating liquid storage tank, the real-time volume flow of the lubricating liquid is calculated.

[0017] Further, the control algorithm in the adaptive control process comprises temperature compensation calculation, which is specifically: according to the reading of the temperature sensor, querying the pre-stored lubricating liquid physical property parameter database to obtain the lubricating liquid density and viscosity value at the current temperature.

[0018] Further, the fault diagnosis in the state monitoring and diagnosis process is specifically:

[0019] The calculated real-time flow rate is compared with the preset target flow rate. If the absolute value of the deviation between the real-time flow rate and the target flow rate is greater than the first threshold, the diagnostic flag is a leakage fault. If the real-time flow rate is continuously lower than the second threshold and the system pressure difference is significantly higher than the normal operating value, the diagnostic flag is a blockage fault. Otherwise, the diagnostic flag is normal.

[0020] Furthermore, in the adaptive control process, when the diagnostic flag is normal, the control signal is calculated as follows:

[0021] The target flow rate, the system pressure difference, and the lubricant density obtained after temperature compensation are substituted into the inverse model based on the orifice flow rate formula to calculate the theoretical flow area value required to achieve the target flow rate. Then, the corresponding fluid replenishment valve control signal is generated based on the theoretical flow area value.

[0022] Furthermore, the state monitoring and diagnosis process and the adaptive control process are executed cyclically to form a closed-loop control;

[0023] The output of the condition monitoring and diagnostic process serves as the input of the adaptive control process. The control signal output by the adaptive control process acts on the fluid replenishment valve, changing the lubricant flow rate, which in turn affects the sensor readings of the condition monitoring and diagnostic process in the next cycle.

[0024] Furthermore, the termination condition of the closed-loop control is: receiving an external system shutdown command, or the fault diagnosis flag remaining in an abnormal state for more than a preset time.

[0025] Furthermore, the controller is also configured to perform cumulative consumption calculation: integrate the calculated real-time flow rate to obtain the total volume of lubricating fluid consumed, and use it for predictive maintenance reminders.

[0026] Furthermore, the replenishing valve is a proportional regulating valve or an on / off solenoid valve; when the replenishing valve is a proportional regulating valve, the control signal is an analog signal or a PWM signal, used to control the valve opening; when the replenishing valve is an on / off solenoid valve, the control signal is a switching signal, and the average flow rate is adjusted by controlling the duty cycle of the switching time within a cycle.

[0027] Furthermore, the controller is communicatively connected to a host computer or remote monitoring system to upload the real-time flow rate, system pressure difference, and fault diagnosis flag information, and to receive target flow rate settings or manual control commands from the host computer or remote monitoring system.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] In practical applications, this invention automatically drips lubricant between the dynamic and stationary rings of the mechanical seal before pump startup, preventing dry friction on the sealing surface due to lack of lubrication during initial operation and significantly reducing wear risk. Simultaneously, the system utilizes the pump's own medium pressure and the compression and release of gas in the storage tank to automatically replenish the lubricant, eliminating the need for external power or frequent manual intervention, thus improving operational convenience and reliability. By storing energy through compressed cavity gas, the system uses the pressure difference to rapidly propel the medium and lubricant into the sealing area upon the next startup, ensuring immediate lubrication of the sealing surface and improving response speed. Continuous and reliable lubrication reduces wear and thermal damage to the sealing surface, significantly extending the service life of the mechanical seal and reducing maintenance costs and downtime. Furthermore, when the control system diagnoses a fault or receives an emergency stop signal, it can immediately close the replenishment valve, cutting off the lubricant supply to prevent the fault from escalating and ensuring system safety.

[0030] This invention features a pre-drilled cavity at the top of a lubricant storage tank, filled with gas. The tank is connected to a pump via two types of pipelines. Opening the replenishment valve allows the gas in the tank's cavity to automatically inject lubricant between the moving and stationary rings of the mechanical seal along the replenishment pipe, pre-filling the sealing surface and preventing dry friction during startup. The pressure generated by the pump's internal medium enters the lubricant storage tank cavity through the exhaust pipe, compressing the gas within the cavity and storing energy. At this point, the cavity pressure balances with the pump's medium pressure, stopping lubricant outflow and preventing excessive consumption. Closing the replenishment valve maintains the high-pressure state within the cavity. Upon the next pump startup, simply opening the replenishment valve allows the stored gas pressure to quickly push the lubricant into the sealing cavity, eliminating the need for secondary manual intervention or external power. No external power (such as an electric pump) is required; automatic lubricant replenishment is achieved solely through the pump's own medium pressure. The lubricant injection response time during initial pump startup is reduced to within 0.5 seconds, completely resolving the dry friction problem during startup. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0033] Figure 2 For the present invention Figure 1 The main view.

[0034] Figure 3 This is a schematic diagram of the overall structure of the mechanical seal of the present invention.

[0035] Figure 4 This is a magnified schematic diagram of part A in part 3 of the present invention.

[0036] Figure 5 This is a flowchart of the condition monitoring and diagnosis process of the present invention.

[0037] Figure label:

[0038] 101 Base, 102 Bracket, 103 Lubricating fluid reservoir, 104 Fluid replenishment pipe, 105 Exhaust pipe, 106 Pump, 107 Shaft sleeve, 108 Pressure cap, 109 Sealing unit, 110 First sealing ring, 111 Main shaft, 112 Equipment housing, 113 Locking plate, 114 Groove, 115 Mounting seat, 116 Spring, 117 Retaining ring, 118 Moving ring, 119 Stationary ring, 120 Second sealing ring, 121 Mounting groove, 122 Wedge sleeve, 123 First clamping sleeve, 124 Second clamping sleeve, 125 First inclined surface, 126 Second inclined surface, 127 Third inclined surface, 128 Screw. Detailed Implementation

[0039] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive. Embodiments of the invention will now be described in detail with reference to the accompanying drawings.

[0040] Example 1:

[0041] See Figures 1-4 This embodiment discloses an auxiliary system for a single-end mechanical seal with anti-dry friction function, including a base 101 and a bracket 102 disposed on the base 101. A lubricating fluid reservoir 103 is disposed on the bracket 102. The lubricating fluid reservoir 103 stores lubricating fluid inside. The top of the lubricating fluid reservoir 103 is a cavity filled with gas.

[0042] The lubricating fluid storage tank 103 is connected to a replenishment pipe 104 and an exhaust pipe 105. One end of the replenishment pipe 104 is located below the surface of the lubricating fluid in the lubricating fluid storage tank 103, and the other end is used to connect to the pump 106. One end of the exhaust pipe 105 is connected to the pump 106, and the other end communicates with the cavity of the lubricating fluid storage tank 103. A replenishment valve is provided on the replenishment pipe 104, and a one-way valve is provided on the exhaust pipe 105.

[0043] When in use, lubricating fluid is poured into the lubricating fluid storage tank 103, which makes the cavity formed in the upper part of the lubricating fluid storage tank 103. Before the pump 106 is working, the replenishment valve is opened, and lubricating fluid is automatically injected into the mechanical seal of the pump 106 between the moving ring 118 and the stationary ring 119 through the replenishment pipe 104.

[0044] When pump 106 is working, the medium generates pressure and enters the lubricating fluid storage tank 103 through the replenishment pipe 104. The air in the upper cavity of the lubricating fluid storage tank 103 is compressed. After pump 106 finishes working, the replenishment valve is closed. When working again, after the valve is opened, due to the high air pressure in the cavity of the lubricating fluid storage tank 103, the medium and lubricating fluid automatically enter the mechanical seal of pump 106 to achieve lubrication.

[0045] The specific work process is as follows:

[0046] 1) Initialization: Fill the lubricating fluid storage tank 103 with lubricating fluid to 4 / 5 of the total volume to form a cavity at the top, and close the fluid replenishment valve;

[0047] 2) Before starting pump 106: Manually open the replenishment valve. The compressed air in the cavity pushes the lubricant along the replenishment pipe 104 into the mechanical seal cavity of pump 106, injecting lubricant between the dynamic ring 118 and the stationary ring 119 (initial injection volume 5mL) to avoid dry friction during startup.

[0048] 3) When pump 106 is working: the medium pressure (0.3MPa) at the outlet of pump 106 enters the cavity through the exhaust pipe 105, the compressed air pressure rises to 0.3MPa, and the lubricating fluid stops flowing out;

[0049] 4) After pump 106 stops: manually close the replenishment valve and maintain a pressure of 0.3 MPa in the cavity;

[0050] 5) Upon the next startup: Open the fluid replenishment valve, and the high-pressure air in the cavity will push the lubricant back into the mechanical seal cavity to complete the lubrication.

[0051] This embodiment requires no electronic components in actual use and is suitable for scenarios without power supply; it achieves automatic lubricant replenishment through air pressure energy storage in the cavity, which solves the problem of dry friction of the mechanical seal when the pump 106 starts / stops, and extends the life of the seal.

[0052] The pump model is ISG50-160, the medium is clean water (temperature 25℃), it is started and stopped 3 times a day, and the test cycle is 30 days. Compared with the seal life without auxiliary system, which is an average of 180 days, the seal life in this embodiment reaches 235 days. The test results show that the seal life is extended by more than 30%.

[0053] Example 2:

[0054] This embodiment is a further optimization based on Embodiment 1. In this embodiment, the liquid replenishment valve is a solenoid valve, and a controller is added, using an STM32F103 microcontroller and multiple sensors.

[0055] Specifically:

[0056] The liquid level sensor has a range of 0-50cm and an accuracy of ±0.1cm. It is installed on the top of the lubricating fluid storage tank 103 to detect the height of the lubricating fluid level.

[0057] The first pressure sensor has a range of 0-1MPa and an accuracy of ±0.01MPa. It is installed on the top of the lubricating fluid reservoir 103 and is used to detect the pressure inside the cavity.

[0058] The second pressure sensor has a range of 0-1MPa and an accuracy of ±0.01MPa. It is installed in the mechanical seal cavity of pump 106 and is used to detect the pressure in the seal cavity.

[0059] The temperature sensor has a range of -20~100℃ and an accuracy of ±0.5℃. It is installed in the middle of the replenishment pipe 104 and is used to detect the temperature of the lubricating fluid.

[0060] The controller's signal input terminals are electrically connected to the aforementioned sensors, and its control output terminals are electrically connected to the control terminals of the solenoid valves.

[0061] In this embodiment, the real-time traffic calculation formula is as follows:

[0062] ;

[0063] in, The current time (in seconds). The previous sampling time (unit: s), where Sampling period; The current liquid level height (unit: m). The liquid level height at the previous moment (unit: m). The cross-sectional area of ​​the lubricant storage tank 103 (unit: m², calculated from the diameter, in this embodiment) is... ; Real-time volumetric flow rate (unit: m³ / s).

[0064] In practice:

[0065] like , ,but:

[0066] .

[0067] System pressure difference calculation: ;

[0068] in, This is the reading from the first pressure sensor (unit: Pa), which represents the pressure inside the cavity. The reading is from the second pressure sensor (unit: Pa), which is the pressure in the mechanical seal cavity. The system pressure difference (unit: Pa) indicates that the cavity pressure is higher than the sealing cavity pressure, providing the power for the flow of lubricating fluid.

[0069] During fault diagnosis, the parameters are defined as follows:

[0070] in, The target flow rate (unit: m³ / h, in this embodiment) );

[0071] First threshold: ;

[0072] Second threshold: ;

[0073] The specific diagnostic logic is as follows:

[0074] like If so, the diagnostic indicator is a leakage fault;

[0075] like If so, the diagnostic indicator is a blockage fault;

[0076] Otherwise, the diagnostic criteria are normal.

[0077] In this embodiment, the adaptive control flow is as follows:

[0078] Temperature compensation calculation: The controller's pre-stored lubricant property parameter database is as follows;

[0079] Define parameters:

[0080] T: Temperature sensor reading (unit: °C);

[0081] Lubricating fluid density (unit: kg / m³);

[0082] Lubricating fluid viscosity (unit: Pa·s);

[0083]

[0084] In practical use, when At that time, by referring to the table, we can find: .

[0085] Control signal calculation, when the diagnostic indicator is normal: Based on the orifice flow formula and its inverse model, define the parameters:

[0086] The flow coefficient is a dimensionless empirical constant obtained through experimental calibration; in this embodiment, C=0.62).

[0087] Theoretical flow area of ​​the replenishing valve, which is the theoretical flow area of ​​the replenishing valve required to achieve the target flow rate (unit: m²).

[0088] PWM signal duty cycle: The control signal for valve opening (range 0-100%);

[0089] Orifice flow rate formula: ;

[0090] Inverse model (solving for theoretical flow area A): ;

[0091] Control signal conversion: preset If the corresponding valve is fully open (duty cycle 100%), then the actual duty cycle D is:

[0092] ;

[0093] in, This refers to the maximum flow area of ​​the replenishing valve.

[0094] The specific calculations are as follows:

[0095] Given:

[0096] but:

[0097] ;

[0098] The controller outputs a PWM signal with a duty cycle of 22% (frequency 1kHz).

[0099] Closed-loop control is as follows:

[0100] The condition monitoring and diagnostic process (cycle 1 second) and the adaptive control process are executed cyclically:

[0101] Sensors collect data and calculate Q. Diagnostic indicators, controller output control signals, adjustment of solenoid valve opening, change of actual flow rate Q, and influence of sensor data in the next cycle.

[0102] Closed-loop control termination condition: When an external shutdown command is received, or when the fault diagnosis flag is abnormal and the duration exceeds 30 seconds, the solenoid valve will automatically close.

[0103] Fully automatic control is achieved through sensors and controllers, which monitor flow, pressure and temperature in real time. The lubricant supply is precisely adjusted through temperature compensation and adaptive algorithms, with a control accuracy of ±5%. It has a fault self-diagnosis function, which can detect leaks or blockages in time and shut down the machine for protection. Compared with Example 1, the life of the seal is extended by more than 2 times, and no manual intervention is required.

[0104] Example 3:

[0105] This embodiment is basically the same as Embodiment 2, except that in this embodiment, the replenishing valve is a proportional regulating valve, model ZAZP-16, with an adjustment range of 0-100% opening. The controller controls the valve opening through a 4-20mA analog signal. A wireless communication module, specifically a 4G module EC20, is added to enable the controller to communicate with the host computer (remote monitoring system).

[0106] The proportional control valve is controlled as follows:

[0107] The correspondence between analog signals and flow area: ;

[0108] in To output an analog signal (unit: mA, range 4-20mA); The maximum flow area of ​​the valve (unit: m², in this embodiment) =0.001m²).

[0109] In actual calculations, when hour, This corresponds to a valve opening of 22%.

[0110] Furthermore, when conducting remote monitoring and data interaction:

[0111] Data upload: The controller uploads real-time flow rate Q and system pressure difference to the host computer every 5 seconds. Fault diagnosis signs, lubricant temperature T;

[0112] Receiving instructions: The host computer can remotely set the target flow rate Q, ranging from 0.05 to 0.2 m³ / h, or send manual control instructions, such as forcibly opening / closing the valve.

[0113] The cumulative consumption is calculated as follows:

[0114] ;

[0115] in:

[0116] Total volume of lubricating fluid consumed (unit: m³).

[0117] System startup time (unit: seconds);

[0118] The actual calculation is achieved through discrete accumulation (accumulating once every 1 second):

[0119] , ( (Number of samples).

[0120] when ( When the total volume of the lubricant storage tank 103 is reached, the controller sends a predictive maintenance reminder.

[0121] This embodiment uses a proportional control valve to improve the flow regulation accuracy (±3%), and combines it with remote monitoring to achieve unattended operation; through cumulative consumption calculation and predictive maintenance reminders, it avoids seal failure caused by lubricant depletion, and is suitable for centralized management of 106 large industrial pumps. After testing, the operation and maintenance efficiency has been improved by more than 40%.

[0122] Example 4:

[0123] See Figures 1-5 This embodiment discloses an auxiliary system for a single-end mechanical seal with anti-dry friction function, including a base 101 and a bracket 102 disposed on the base 101. A lubricating fluid reservoir 103 is disposed on the bracket 102. The lubricating fluid reservoir 103 stores lubricating fluid inside. The top of the lubricating fluid reservoir 103 is a cavity filled with gas.

[0124] The lubricating fluid storage tank 103 is connected to a replenishment pipe 104 and an exhaust pipe 105. One end of the replenishment pipe 104 is located below the surface of the lubricating fluid in the lubricating fluid storage tank 103, and the other end is used to connect to the pump 106. One end of the exhaust pipe 105 is connected to the pump 106, and the other end communicates with the cavity of the lubricating fluid storage tank 103. A replenishment valve is provided on the replenishment pipe 104, and a one-way valve is provided on the exhaust pipe 105.

[0125] When in use, lubricating fluid is poured into the lubricating fluid storage tank 103, which makes the cavity formed in the upper part of the lubricating fluid storage tank 103. Before the pump 106 is working, the replenishment valve is opened, and lubricating fluid is automatically injected into the mechanical seal of the pump 106 between the moving ring 118 and the stationary ring 119 through the replenishment pipe 104.

[0126] When pump 106 is working, the medium generates pressure and enters the lubricating fluid storage tank 103 through the replenishment pipe 104. The air in the upper cavity of the lubricating fluid storage tank 103 is compressed. After pump 106 finishes working, the replenishment valve is closed. When working again, after the valve is opened, due to the high air pressure in the cavity of the lubricating fluid storage tank 103, the medium and lubricating fluid automatically enter the mechanical seal of pump 106 to achieve lubrication.

[0127] In this embodiment, the mechanical seal has the following specific structure:

[0128] It includes a bushing 107, a gland 108, and a sealing unit 109. The bushing 107 is used to be installed on the main shaft 111 of the equipment, and the sealing unit 109 is fitted on the bushing 107. The gland 108 is used to be installed on the equipment housing 112. A first sealing ring 110 is provided between the gland 108 and the equipment housing 112.

[0129] The pressure cap 108 is fixedly provided with a locking piece 113, and the bushing 107 is provided with a groove 114, with the locking piece 113 located in the groove 114.

[0130] Furthermore, the sealing unit 109 includes a mounting base 115, a spring 116, a retaining ring 117, a moving ring 118, a stationary ring 119, and a second sealing ring 120. The mounting base 115 is fitted onto the bushing 107, and a mounting groove 121 is provided on the mounting base 115. The spring 116 is located in the mounting groove 121. The retaining ring 117, the moving ring 118, and the stationary ring 119 are arranged sequentially and fitted onto the bushing 107. The side of the spring 116 away from the mounting base 115 contacts the retaining ring 117. The second sealing ring 120 is located between the stationary ring 119 and the pressure cap 108. Under the action of the spring 116, the moving ring 118 tends to move towards the end closer to the stationary ring 119. The end cap is provided with two connection ports, which are respectively connected to the replenishment pipe 104 and the exhaust pipe 105. Furthermore, the pressure cap 108 is also provided with a flushing pipe and a drain pipe, and valves are provided on both the flushing pipe and the drain pipe.

[0131] Furthermore, a wedge sleeve 122 is also provided on the main shaft 111 of the equipment. A first clamping sleeve 123 and a second clamping sleeve 124 are fitted on the outside of the wedge sleeve 122. A first inclined surface 125 and a second inclined surface 126 are provided on the outside of the wedge sleeve 122. A third inclined surface 127 corresponding to the first inclined surface 125 and the second inclined surface 126 is provided on the first clamping sleeve 123 and the second clamping sleeve 124. The first clamping sleeve 123 and the second clamping sleeve 124 are connected by a screw 128. Under the action of the screw 128, the first clamping sleeve 123 and the second clamping sleeve 124 are brought closer to each other to squeeze the wedge sleeve 122, so that the wedge sleeve 122 fits against the main shaft 111 of the equipment.

[0132] The first inclined plane 125 and the second inclined plane 126 have opposite inclination directions.

[0133] In this embodiment, the mechanical seal structure takes the bushing, gland, and sealing unit as its core framework. Through the precise fit between the components and the transmission of force, it achieves the dual functions of tight sealing surface to prevent leakage and adapting to the lubrication supply of the auxiliary system.

[0134] In actual use, the bushing 107 is fitted onto the main shaft 111 of the equipment as the mounting carrier for the sealing unit 109; the pressure cap 108 is fixed to the outer casing 112 of the equipment, and the first sealing ring 110 blocks the gap leakage between the pressure cap and the outer casing; at the same time, the locking piece 113 on the pressure cap 108 is embedded in the groove 114 of the bushing 107, restricting the relative rotation of the bushing 107 and the pressure cap 108, ensuring that the sealing unit 109 is in a stable position when the main shaft rotates, and avoiding damage to the sealing surface due to component misalignment.

[0135] Meanwhile, the sealing unit 109 achieves a tight fit between the rotating ring 118 and the stationary ring 119 through spring force. The mounting seat 115 is fixed to the bushing 107. The spring 116 in the mounting groove 121 applies a continuous axial thrust to the retaining ring 117. The retaining ring 117 transmits the force to the rotating ring 118, so that the rotating ring 118 always presses the stationary ring 119. The stationary ring 119 is fixed to the gland 108 by the second sealing ring 120 and remains in the same position. When the main shaft 111 drives the bushing 107, the mounting seat 115, and the rotating ring 118 to rotate, the contact surface between the rotating ring and the stationary ring forms a dynamic sealing strip, blocking the leakage of the medium inside the pump.

[0136] The two connection ports on the gland 108 are respectively connected to the replenishment pipe 104 and the exhaust pipe 105 of the auxiliary system. The lubricating fluid delivered by the replenishment pipe 104 can be directly injected into the mating surface of the moving ring 118 and the stationary ring 119 to solve the lubrication problem of the sealing surface. The exhaust pipe 105 transmits the pressure of the medium in the pump to the cavity of the lubricating fluid storage tank to provide a pressure source for the pneumatic energy storage of the auxiliary system. At the same time, the flushing pipe on the gland 108 can be used to flush the sealing surface with clean medium when needed, and the drain pipe discharges waste lubricating fluid or flushing fluid to ensure the cleanliness of the sealing surface.

[0137] The wedge sleeve 122 on the main shaft 111 is engaged with the first clamping sleeve 123 and the second clamping sleeve 124 through a bevel fit and screw locking, thereby achieving rigid fixation between the bushing 107 and the main shaft 111. The first bevel 125 and the second bevel 126 on the outer side of the wedge sleeve 122 have opposite inclination directions and respectively fit with the third bevel 127 on the clamping sleeve. When the screw 128 is tightened, the two clamping sleeves come closer to each other, and the squeezing action between the bevels causes the wedge sleeve 122 to contract radially and fit tightly against the surface of the main shaft 111, avoiding relative sliding between the bushing 107 and the main shaft 111, ensuring that the rotating ring 118 rotates synchronously with the main shaft, and preventing additional wear on the sealing surface due to the speed difference.

[0138] Furthermore, the replenishing valve can be a manual valve or a solenoid valve; in this embodiment, the replenishing valve is a solenoid valve.

[0139] Furthermore, the auxiliary system also includes a controller and multiple sensors, including a level sensor for detecting the level of the lubricating fluid reservoir 103, a first pressure sensor for detecting the pressure of the lubricating fluid reservoir 103, a second pressure sensor for detecting the pressure of the sealing chamber of the pump 106, and a temperature sensor.

[0140] The controller signal input terminal is electrically connected to the signal output terminal of the plurality of sensors, and the controller control output terminal is electrically connected to the control terminal of the liquid replenishment valve.

[0141] The controller is configured as follows:

[0142] Condition monitoring and diagnosis process: Read the measurement values ​​of the multiple sensors and calculate the real-time flow rate, system pressure difference, and fault diagnosis indicators;

[0143] Adaptive control process: Receive the output results of the status monitoring and diagnosis process. If the diagnostic flag is normal, calculate and output a control signal to the replenishment valve based on the system pressure difference and temperature sensor readings using a pre-stored control algorithm. If the diagnostic flag is abnormal, output a control signal to close the replenishment valve.

[0144] Furthermore, the calculation of real-time flow rate in the status monitoring and diagnosis process is specifically as follows: based on the difference between the liquid level sensor reading at the current time and the previous time, and combined with the cross-sectional area of ​​the lubricating fluid storage tank 103, the real-time volumetric flow rate of the lubricating fluid is calculated.

[0145] Furthermore, the control algorithm in the adaptive control process includes temperature compensation calculation, specifically: based on the reading of the temperature sensor, querying the pre-stored lubricant property parameter database to obtain the lubricant density and viscosity values ​​at the current temperature.

[0146] Furthermore, the fault diagnosis in the condition monitoring and diagnosis process specifically includes:

[0147] The calculated real-time flow rate is compared with the preset target flow rate. If the absolute value of the deviation between the real-time flow rate and the target flow rate is greater than the first threshold, the diagnostic flag is a leakage fault. If the real-time flow rate is continuously lower than the second threshold and the system pressure difference is significantly higher than the normal operating value, the diagnostic flag is a blockage fault. Otherwise, the diagnostic flag is normal.

[0148] Furthermore, in the adaptive control process, when the diagnostic flag is normal, the control signal is calculated as follows:

[0149] The target flow rate, the system pressure difference, and the lubricant density obtained after temperature compensation are substituted into the inverse model based on the orifice flow rate formula to calculate the theoretical flow area value required to achieve the target flow rate. Then, the corresponding fluid replenishment valve control signal is generated based on the theoretical flow area value.

[0150] Furthermore, the state monitoring and diagnosis process and the adaptive control process are executed cyclically to form a closed-loop control;

[0151] The output of the condition monitoring and diagnostic process serves as the input of the adaptive control process. The control signal output by the adaptive control process acts on the fluid replenishment valve, changing the lubricant flow rate, which in turn affects the sensor readings of the condition monitoring and diagnostic process in the next cycle.

[0152] Furthermore, the termination condition of the closed-loop control is: receiving an external system shutdown command, or the fault diagnosis flag remaining in an abnormal state for more than a preset time.

[0153] Furthermore, the controller is also configured to perform cumulative consumption calculation: integrate the calculated real-time flow rate to obtain the total volume of lubricating fluid consumed, and use it for predictive maintenance reminders.

[0154] Furthermore, the replenishing valve is a proportional regulating valve or an on / off solenoid valve;

[0155] When the replenishing valve is a proportional regulating valve, the control signal is an analog signal or a PWM signal, used to control the valve opening degree;

[0156] When the replenishment valve is a switchable solenoid valve, the control signal is a switching signal, and the average flow rate is adjusted by controlling the duty cycle of the switching time within a cycle.

[0157] Furthermore, the controller is communicatively connected to a host computer or remote monitoring system to upload the real-time flow rate, system pressure difference, and fault diagnosis flag information, and to receive target flow rate settings or manual control commands from the host computer or remote monitoring system.

[0158] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An auxiliary system for a single-end mechanical seal with anti-dry friction function, characterized in that, It includes a base and a bracket mounted on the base. A lubricant reservoir is mounted on the bracket. The lubricant reservoir stores lubricant inside. The top of the lubricant reservoir is a cavity filled with gas. The lubricating fluid storage tank is connected to a replenishment pipe and an exhaust pipe. One end of the replenishment pipe is below the surface of the lubricating fluid in the storage tank, and the other end is used to connect to the pump. One end of the exhaust pipe is connected to the pump, and the other end is connected to the cavity of the lubricating fluid storage tank. A replenishment valve is installed on the replenishment pipe, and a check valve is installed on the exhaust pipe. When in use, lubricating fluid is poured into the lubricating fluid storage tank, which forms the cavity at the top of the lubricating fluid storage tank. Before the pump starts working, the replenishment valve is opened, and lubricating fluid is automatically injected into the space between the moving ring and the stationary ring of the pump's mechanical seal through the replenishment pipe. When the pump is working, the medium is pressurized and enters the lubricating fluid storage tank through the replenishment pipe. The air in the upper cavity of the lubricating fluid storage tank is compressed. After the pump stops working, the replenishment valve is closed. When the pump starts working again, the valve is opened. Due to the high air pressure in the lubricating fluid storage tank, the medium and lubricating fluid automatically enter the pump's mechanical seal to achieve lubrication. The replenishing valve is a proportional regulating valve or an on / off solenoid valve; when the replenishing valve is a proportional regulating valve, the control signal is an analog signal or a PWM signal, used to control the valve opening; when the replenishing valve is an on / off solenoid valve, the control signal is a switching signal, and the average flow rate is adjusted by controlling the duty cycle of the switching time within one cycle. The controller communicates with a host computer or remote monitoring system to upload real-time flow, system pressure difference, and fault diagnosis information, and to receive target flow setpoints or manual control commands from the host computer or remote monitoring system.

2. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 1, characterized in that: The auxiliary system also includes a controller and multiple sensors, including a level sensor for detecting the level of the lubricating fluid tank, a first pressure sensor for detecting the pressure of the lubricating fluid tank, a second pressure sensor for detecting the pressure of the pump sealing chamber, and a temperature sensor. The controller signal input terminal is electrically connected to the signal output terminal of the plurality of sensors, and the controller control output terminal is electrically connected to the control terminal of the liquid replenishment valve. The controller is configured as follows: Condition monitoring and diagnosis process: Read the measurement values ​​of the multiple sensors and calculate the real-time flow rate, system pressure difference, and fault diagnosis indicators; Adaptive control process: Receive the output results of the status monitoring and diagnosis process. If the diagnostic flag is normal, calculate and output a control signal to the replenishment valve based on the system pressure difference and temperature sensor readings using a pre-stored control algorithm. If the diagnostic flag is abnormal, output a control signal to close the replenishment valve.

3. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 2, characterized in that, The real-time flow rate calculation in the status monitoring and diagnosis process is specifically as follows: based on the difference between the liquid level sensor reading at the current time and the previous time, and combined with the cross-sectional area of ​​the lubricating fluid storage tank, the real-time volumetric flow rate of the lubricating fluid is calculated.

4. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 3, characterized in that, The control algorithm in the adaptive control process includes temperature compensation calculation, specifically: based on the reading of the temperature sensor, query the pre-stored lubricant property parameter database to obtain the lubricant density and viscosity values ​​at the current temperature.

5. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 4, characterized in that, The fault diagnosis in the condition monitoring and diagnosis process specifically includes: The calculated real-time flow rate is compared with the preset target flow rate. If the absolute value of the deviation between the real-time flow rate and the target flow rate is greater than the first threshold, the diagnostic flag is a leakage fault. If the real-time flow rate is continuously lower than the second threshold and the system pressure difference is significantly higher than the normal operating value, the diagnostic flag is a blockage fault. Otherwise, the diagnostic flag is normal.

6. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 5, characterized in that, In the adaptive control process, when the diagnostic flag is normal, the control signal is calculated as follows: The target flow rate, the system pressure difference, and the lubricant density obtained after temperature compensation are substituted into the inverse model based on the orifice flow rate formula to calculate the theoretical flow area value required to achieve the target flow rate. Then, the corresponding fluid replenishment valve control signal is generated based on the theoretical flow area value.

7. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 6, characterized in that, The state monitoring and diagnosis process and the adaptive control process are executed cyclically to form a closed-loop control. The output of the condition monitoring and diagnostic process serves as the input of the adaptive control process. The control signal output by the adaptive control process acts on the fluid replenishment valve, changing the lubricant flow rate, which in turn affects the sensor readings of the condition monitoring and diagnostic process in the next cycle.

8. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 7, characterized in that, The closing-loop control ends when an external system shutdown command is received, or when the fault diagnosis flag remains in an abnormal state for more than a preset time.

9. The auxiliary system for a single-end mechanical seal with anti-dry friction function according to claim 1, characterized in that, The controller is also configured to perform cumulative consumption calculations: The calculated real-time flow rate is integrated to obtain the total volume of lubricating fluid consumed, which is then used for predictive maintenance reminders.

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