Large temperature change high pressure ball valve

Abstract

The present application relates to the technical field of ball valves, and particularly relates to a large-temperature-change high-pressure ball valve, which comprises a valve body, a main valve core arranged in the valve body, a sensor assembly, an execution assembly and a controller; the controller is configured to acquire a real-time opening degree signal of the main valve core, a real-time pressure signal and a real-time temperature signal in a middle cavity; the action state of the main valve core is judged based on the real-time opening degree signal, and the pressure change slope of the real-time pressure signal is calculated; it is judged whether the action state is in an opening-closing transition state or a full-closing steady state, and corresponding preset slope thresholds are called according to the action state, and the pressure change slope is compared, and overpressure hidden danger is judged in combination with the trend of the real-time temperature signal; corresponding pressure relief actions are executed, and when it is judged that there is overpressure hidden danger, a bypass valve is opened to release pressure; through an independent pressure relief channel and a control strategy, the present application eliminates extreme pressure holding hidden danger, avoids wear of a main valve sealing surface, and is suitable for large-temperature-change high-pressure working conditions.

Description

Technical Field

[0001] This invention relates to the field of ball valve technology, specifically to a high-pressure ball valve with large temperature variation. Background Technology

[0002] High-pressure ball valves with large temperature variations are a key means of achieving fluid cutoff and regulation in complex temperature fields such as cryogenic, extremely cold, or extremely high temperatures. They are widely used in energy fields such as liquid hydrogen storage and transportation, liquefied natural gas (LNG) stations, and coal chemical industry. Through the precise fit between the ball and the valve seat sealing pair, zero leakage of the medium is maintained under conditions of extreme pressure difference and drastic temperature fluctuations, thereby achieving the technical effect of ensuring the safe operation of pipeline systems and stable energy transmission.

[0003] Current designs for high-pressure ball valves with large temperature variations often employ a long-neck bonnet structure combined with a single piston-effect valve seat, or a combination of a double piston-effect valve seat and an external mechanical pressure relief pipeline. However, in practical applications, such designs often suffer from specific defects such as insufficient adaptability to extreme environments and low pressure relief reliability.

[0004] Chinese patent CN119712909A discloses a high-safety ball valve with automatic pressure relief, relating to the field of ball valve technology. The ball valve includes an inlet connector, an outlet connector, a first pressure relief assembly, a second pressure relief assembly, a third pressure relief assembly, a fourth pressure relief assembly, a fifth pressure relief assembly, a buffer assembly, a drive module, a valve stem, an intermediate valve seat, and a connecting rod. The pressure values ​​required to open the first, second, third, fourth, and fifth pressure relief assemblies increase sequentially. When the first pressure relief assembly is stably open, the second pressure relief assembly begins to open; when the second pressure relief assembly is stably open, the third pressure relief assembly begins to open; when the third pressure relief assembly is stably open, the fourth pressure relief assembly begins to open; and after the fourth pressure relief assembly is stably open, the fifth pressure relief assembly is fully open. The buffer assembly achieves rapid pressure relief while reducing the impact force of the medium on the ball, ensuring a stable connection between the ball and the valve stem, and extending the service life of the ball valve.

[0005] While the aforementioned documents achieve rapid pressure relief through buffer components while reducing the impact force of the medium on the ball, ensuring a stable connection between the ball and the valve stem, and extending the service life of the ball valve, they still reveal significant limitations in core scenarios involving the accumulation of cryogenic liquids and continuous input of ambient heat. Specifically: When the valve is closed, a portion of the cryogenic medium will inevitably be trapped in the central cavity of the valve body. When heat from the external environment is conducted in through the valve body, this portion of the medium will rapidly absorb heat and vaporize. In the closed, constant volume (i.e., the central cavity), this phase change will generate enormous expansion pressure. If the pressure relief structure (such as a single-piston effect pressure relief channel) is blocked by ice or fails, it can easily lead to valve body rupture or breakage of fastening bolts.

[0006] To address the problem of abnormal overpressure in the central cavity, existing technologies typically deploy a pressure sensor in the central cavity and set a fixed pressure threshold to trigger an active pressure relief action when the pressure exceeds the limit. However, this conventional approach inevitably leads to serious negative consequences in specific scenarios such as the valve opening and closing transition state.

[0007] During the initial opening or final closing of a valve, the drastic change in fluid velocity can cause significant water hammer or cavitation, resulting in instantaneous pressure fluctuations. This causes unsteady fluctuations in the pressure data collected by the sensor. Since existing logic algorithms use only pressure values ​​as a single criterion, they cannot effectively distinguish between normal operating pressure pulsations and actual pressure build-up risks. Consequently, the system frequently triggers pressure relief actions at unnecessary times, resulting in unnecessary waste of media and further exacerbating the overall pressure instability of the pipeline system. Summary of the Invention

[0008] The purpose of this invention is to provide a high-pressure ball valve with large temperature variation to solve the technical problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-pressure ball valve with large temperature variation, including a valve body and a main valve core disposed in the valve body, as well as a sensor assembly, an actuation assembly and a controller; The sensor assembly is used to collect pressure signals, temperature signals, and the opening signal of the main valve core within the valve body cavity; the actuation assembly includes a bypass valve communicating with the valve body cavity; the controller is electrically connected to the sensor assembly and the bypass valve. The controller is configured to: Acquire the real-time opening signal of the main valve core, the real-time pressure signal and the real-time temperature signal in the middle cavity; The operating state of the main valve core is determined based on the real-time opening signal, and the pressure change slope of the real-time pressure signal is calculated. Determine whether the action state is in an open / close transition state or a fully closed steady state, and compare the corresponding preset slope threshold with the pressure change slope based on the action state, and combine the trend of the real-time temperature signal to determine the overpressure risk. Perform the corresponding pressure relief action. If an overpressure risk is detected, control the bypass valve to open to relieve pressure.

[0010] Preferably, the process involves comparing the pressure change slope with a preset slope threshold based on the current action state, including: When the real-time opening signal indicates that the main valve core is in the opening-closing transition state, the controller acquires the opening change rate of the main valve core; A first preset slope threshold is generated, which is positively correlated with the opening change rate and dynamically adjusted according to the action rate of the main valve core. The pressure change slope is compared with a first preset slope threshold to filter transient water hammer pulses or pressure fluctuations caused by high-speed fluid impact.

[0011] Preferably, when the real-time opening signal exceeds the set range of the opening and closing transition state, indicating that the main valve core is in a normally open flow state, it is determined that the middle cavity does not have the conditions for sealing and pressure buildup, and the controller controls the bypass valve to remain closed and enter the standby state.

[0012] Preferably, the overpressure hazard assessment is based on the trend of the real-time temperature signal, including: When the real-time opening signal indicates that the main valve core is in a fully closed steady state, the controller calculates the slope of the theoretical saturated vapor pressure change under the current temperature conditions in conjunction with the real-time temperature signal, and performs temperature compensation to generate a second preset slope threshold. When the slope of the pressure change exceeds the second preset slope threshold and the real-time temperature signal shows a continuous upward trend, it is determined that the medium is undergoing phase change and vaporization in the cavity, indicating a real overpressure hazard.

[0013] Preferably, controlling the bypass valve to open for pressure relief includes: The controller outputs a pulse width modulation signal to the bypass valve; The bypass valve is opened in a high-frequency, minute manner by controlling the pulse width modulation signal, so that the high-pressure medium accumulated in the middle cavity can be smoothly discharged to the downstream through the bypass guide channel and independent pipeline.

[0014] Preferably, the controller continuously monitors the real-time pressure signal in the middle cavity until the real-time pressure signal in the middle cavity falls below the set safety baseline, at which point the bypass valve is automatically closed.

[0015] Preferably, the processing logic for calculating the slope of the pressure change in the real-time pressure signal includes: Input discrete pressure samples collected continuously over a time series and calculate the ratio of the pressure difference between adjacent time points to the time difference. This ratio is output as the current pressure change slope to represent the dynamic rate of increase and decrease of pressure within the cavity.

[0016] Preferably, the processing logic for generating the first preset slope threshold includes: Input the extracted absolute value form of the opening change rate into the preset correlation model; The absolute value form of the opening change rate is scaled proportionally based on the first preset system correlation coefficient, and the second preset system correlation coefficient is superimposed as the basic compensation amount. The output scaled and compensated value is used as the first preset slope threshold to achieve dynamic coupling between the judgment benchmark and the intensity of the main valve core's mechanical movement.

[0017] Preferably, the sensor assembly includes a high-pressure resistant thin-film pressure sensor and a low-temperature temperature probe installed inside the valve body cavity, and also includes an absolute encoder connected to the top of the valve stem. The bypass valve includes a PWM micro-controlled electromagnetic bypass valve. The inlet end of the PWM micro-controlled electromagnetic bypass valve is connected to the middle cavity through a flow guide channel, and its pressure relief outlet end is connected to the downstream pipeline of the valve or the discharge and recovery system via an independent pipeline.

[0018] Preferably, the sensor leads of the high-pressure resistant thin-film pressure sensor and the low-temperature temperature probe are covered with a low thermal conductivity composite material.

[0019] The technical effects and advantages of this invention are as follows: 1. This invention monitors the valve closing speed in real time and dynamically adjusts the pressure alarm threshold according to the speed; the faster the valve closes, the higher the alarm threshold is automatically adjusted, thereby effectively filtering out normal pressure fluctuations when the valve is opened and closed, ensuring that the bypass valve is only activated when there is real danger, avoiding malfunctions and ensuring the smooth operation of the pipeline.

[0020] 2. This invention monitors the rate of increase of pressure in the cavity and whether the temperature is continuously rising. When the real-time pressure change slope measured and calculated by the pressure sensor exceeds the second preset slope threshold, and the temperature probe confirms that the temperature in the cavity is in a continuous rising process, the system will determine that a "pressure buildup" phenomenon is indeed occurring in the sealed space of the cavity, rather than a false alarm caused by sensor failure or random interference, and thus trigger a pressure relief action. Attached Figure Description

[0021] Figure 1 This is a system architecture diagram of the present invention; Figure 2 This is the control flowchart of the present invention; Figure 3 This is a schematic diagram of the ball valve of the present invention.

[0022] In the picture: 1. Valve body; 2. Main valve core; 3. Bypass valve Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 In the case of cryogenic pipelines, when the valve is closed, a portion of the cryogenic medium will inevitably be trapped in the cavity of the valve body 1. When heat from the external environment is conducted in through the valve body 1, pressure buildup is likely to occur due to the medium absorbing heat and undergoing phase change and vaporization. Furthermore, when the existing technology processes the logic, the actions at the initial stage of valve opening or the final stage of valve closing will produce significant water hammer or cavitation phenomena due to drastic changes in fluid velocity, causing instantaneous pressure fluctuations and leading to frequent pressure relief actions triggered by the system at unnecessary times.

[0025] In view of this, refer to Figures 1 to 3 As shown, this embodiment proposes a high-temperature variable high-pressure ball valve, including a valve body 1 and a main valve core 2 disposed in the valve body 1, as well as a sensor assembly, an actuator assembly and a controller; the sensor assembly is used to collect valve operation data; the actuator assembly is used to perform high-frequency micro-discharge.

[0026] During equipment operation, the controller continuously acquires real-time data collected by the sensor components and executes the corresponding open / close transition state anti-misjudgment logic or the phase change overpressure judgment logic of the fully closed steady state according to the real-time opening state of the main valve core 2. When an overpressure risk is detected, the controller drives the execution component (i.e., bypass valve 3) to release pressure through the pulse width modulation signal, so as to reduce the wear of the main valve sealing surface and reduce the evacuation of the medium.

[0027] In terms of hardware layout and data acquisition system construction, the sensor component is used to collect pressure signals, temperature signals and opening signals of the main valve core 2 in the cavity of valve body 1; the actuation component includes a bypass valve 3 that communicates with the cavity of valve body 1; the controller is electrically connected to the sensor component and the bypass valve 3. The sensor assembly includes a high-pressure resistant thin-film pressure sensor and a low-temperature temperature probe installed inside the cavity of the valve body 1, as well as an absolute encoder connected to the top of the valve stem; the bypass valve 3 includes a PWM micro-controlled electromagnetic bypass valve, the inlet of which is connected to the cavity through a flow channel, and its pressure relief outlet is connected to the downstream pipeline of the valve or a discharge and recovery system via an independent pipeline.

[0028] Specifically, the probe end faces of the high-pressure resistant thin-film pressure sensor and the low-temperature temperature probe are set in the sealed volume of the middle cavity composed of a ball and a valve seat, so as to realize the sensing of the thermodynamic state of the fluid. An absolute encoder is coaxially locked to the top of the drive valve stem of the main valve core 2 via a rigid coupling, and is used to convert the mechanical rotation angle of the valve stem into a high-precision digital opening signal. In the design of the pressure relief circuit, the PWM micro-controlled electromagnetic bypass valve serves as an independent fluid shut-off actuator, with its inlet end connected to the central cavity and its outlet end connected to the independent relief and recovery system.

[0029] As a typical application scenario, in the loading pipeline of an LNG receiving station, when an abnormal pressure rise occurs in the central cavity, the high-pressure LNG vaporization gas in the central cavity can be directly diverted to the low-pressure recovery pipeline network inside the station by opening the PWM micro-controlled electromagnetic bypass valve.

[0030] The aforementioned independent pressure relief circuit enables the pressure relief action to be independent of the mechanical movement of the main valve core 2, thereby avoiding severe cavitation and mechanical damage to the precision hard or soft seal surfaces caused by frequent micro-movements of the main valve core 2 under extremely high pressure differentials, and improving the long-term sealing life and operational reliability of the overall valve.

[0031] It should be noted that, in order to reduce the impact of cryogenic conditions on electronic signal transmission, the sensor leads of the high-pressure resistant thin-film pressure sensor and the low-temperature temperature probe in this embodiment are covered with low thermal conductivity composite materials to reduce the cold bridge effect.

[0032] After acquiring the above sensor data, the controller executes the following control logic: Specifically, the real-time opening signal of the main valve core 2, the real-time pressure signal and the real-time temperature signal in the middle cavity are acquired; The operating state of the main valve core 2 is determined based on the real-time opening signal, and the pressure change slope of the real-time pressure signal is calculated. Determine whether the action state is in an open / close transition state or a fully closed steady state, and compare the corresponding preset slope threshold with the pressure change slope based on the action state, and combine the trend of the real-time temperature signal to determine the overpressure risk. The corresponding pressure relief action is executed. When it is determined that there is a risk of overpressure, the bypass valve 3 is opened to relieve pressure.

[0033] Specifically, the microprocessor inside the controller synchronously reads and refreshes multi-dimensional data at a preset high-frequency clock cycle. The multi-dimensional data includes the opening signal from the absolute encoder, the pressure signal from the high-pressure resistant thin-film pressure sensor, and the temperature signal from the low-temperature temperature probe.

[0034] The opening, pressure, and temperature signals acquired in real time are stored in the data buffer area to comprehensively construct the current internal operating status of the central cavity.

[0035] Subsequently, the microprocessor initiates a pre-set logic judgment program based on the specific value of the opening to determine the next direction of analysis. The opening value is divided into several different ranges. When the opening value is large, it means that the medium can flow normally. When the opening value is in a narrow range of change, close to fully closed or fully open, it means that the fluid state is changing drastically. When the opening value is precisely displayed as completely closed, it means that the cavity has formed a closed space and is in a high-risk state.

[0036] After clarifying the current situation, the system begins to focus on analyzing the pressure signal. The calculation module processes a series of continuously collected pressure data and uses a differential algorithm to calculate the ratio of the pressure difference between adjacent or close time points to the corresponding time difference. This allows the system to differentiate the relationship between pressure and time. The output of this calculation is the slope of the pressure change at the current moment. This slope value directly reflects the instantaneous rate of pressure rise or fall in the cavity and is the core dynamic indicator for judging the severity of pressure buildup.

[0037] Under different circumstances, the system will invoke the calculation rules that match the situation to dynamically generate a specific judgment threshold. For example, during the transition process of valve opening and closing, the threshold may be related to the speed of the main valve core 2's movement. In the stable state where the valve is fully closed, the threshold may be calculated by the thermodynamic model based on the real-time temperature. Then, the system will compare the calculated real-time pressure change slope with this dynamically generated threshold.

[0038] Meanwhile, temperature data is used as an auxiliary verification; for example, in the fully shut-off state, it is necessary to verify whether the temperature is continuously rising to prove that there is heat input and medium phase change, so as to achieve a comprehensive assessment of pressure change characteristics and the current thermal environment.

[0039] Finally, the microprocessor makes a comprehensive judgment based on the comparison between the pressure slope and the dynamic threshold, combined with the trend of temperature change. Only when the pressure slope exceeds the dynamic reference and the temperature change trend is in line with expectations will the system determine that there is a real risk of overpressure. At this time, the microprocessor will generate a corresponding control command, which will activate the corresponding circuit and send a signal to the power amplifier circuit responsible for driving the bypass valve 3, thereby controlling the PWM micro-controlled electromagnetic bypass valve to open and complete the pressure relief action.

[0040] Through the above technical solution, the system can dynamically adjust the judgment criteria according to the valve opening and pressure changes, effectively filter out misjudgments caused by transient water hammer interference, and achieve accurate identification and pressure relief control of the actual overpressure risk in the middle cavity.

[0041] When an overpressure risk is detected and pressure relief is initiated, the control logic in this embodiment includes: Specifically, the controller outputs a pulse width modulation signal to the bypass valve 3; the pulse width modulation signal controls the bypass valve 3 to open slightly at high frequency, so that the high pressure medium accumulated in the middle cavity is smoothly discharged to the downstream through the bypass guide channel and independent pipeline. The controller continuously monitors the real-time pressure signal in the cavity until the real-time pressure signal in the cavity drops below the set safety baseline, at which point the bypass valve 3 is automatically closed.

[0042] When the valve is completely closed, its internal cavity forms a sealed space. If the residual cryogenic medium inside undergoes a phase change and vaporizes due to absorbing heat from the environment, it will generate a fluid with extremely high pressure. If the bypass relief valve is opened directly and completely at this time, the huge pressure difference between the cavity and the external low-pressure environment will cause the fluid to be ejected at extremely high speed. This violent release will not only generate a destructive secondary shock wave in the pressure relief channel, but will also easily damage the valve core of the miniature electromagnetic bypass valve.

[0043] Therefore, in this embodiment, the controller uses pulse width modulation technology to drive the bypass valve 3. The controller outputs a series of square wave electrical signals with fixed frequency but adjustable width. By dynamically adjusting the proportion of high-level time in one cycle, i.e., the duty cycle, the average voltage and current applied to the electromagnetic coil of the bypass valve 3 can be precisely controlled, thereby indirectly and finely adjusting the magnetic force generated by the coil. This adjustment method ensures that the magnetic force acting on the valve core of bypass valve 3 is not constant, but rather in a high-frequency oscillating equilibrium state. Driven by this oscillating magnetic force, the valve core of bypass valve 3 is not fully opened to its maximum stroke, but remains in a suspended state of high-frequency, small-amplitude back-and-forth vibration. This artificially creates an extremely small throttling gap between the valve core and the valve seat, the opening of which can be adjusted at any time. By changing the duty cycle of the PWM signal, the opening of this equivalent throttling gap can be continuously and smoothly changed, thereby controlling the amount of discharge flow and achieving a smooth and controllable release of high-pressure fluid.

[0044] Throughout the depressurization process, the controller continuously monitors the real-time pressure signal within the cavity, forming a closed-loop automatic adjustment circuit. A target safe pressure value is preset within the controller. The system compares the real-time monitored pressure value with this target safe value and dynamically adjusts the duty cycle of the PWM signal based on the difference between the two: when the actual pressure is significantly higher than the safe value, the duty cycle increases, slightly widening the equivalent throttling gap and accelerating depressurization; as the medium leaks out, the cavity pressure begins to decrease. When the pressure value approaches the safe target, the duty cycle automatically decreases, narrowing the throttling gap and slowing the depressurization rate, ensuring a smooth and controllable pressure decrease and avoiding drastic fluctuations; once the pressure sensor confirms that the cavity pressure has fallen below the preset safe baseline, the controller immediately adjusts the PWM signal duty cycle to zero, completely de-energizes the electromagnetic coil, and the bypass valve 3's valve core quickly and completely closes under the action of the return spring, cutting off the discharge channel.

[0045] The above technical solution enables the buffered release of ultra-high pressure energy in the central cavity, avoiding the severe impact and vibration caused by transient and violent release to the pipeline system, and accurately cutting off the fluid at the moment of eliminating danger, thus achieving a smooth and controllable release process.

[0046] Example 2 While the above embodiments can achieve buffered release of the medium in the cavity, significant water hammer or cavitation effects can occur during the initial opening or final closing stages of the valve due to drastic changes in fluid velocity. This can cause instantaneous pressure fluctuations, leading to frequent pressure relief actions triggered by the system at unnecessary times. Therefore, this embodiment is a further improvement upon Embodiment 1.

[0047] Reference Figures 1 to 2 As shown, specifically, the processing logic for calculating the pressure change slope of the real-time pressure signal includes: inputting continuously acquired discrete pressure sample values ​​from the time series, calculating the ratio of the pressure difference between adjacent time nodes to the time difference; and outputting this ratio as the current pressure change slope to represent the dynamic rise and fall rate of the pressure in the cavity.

[0048] In industrial settings, valves are exposed to complex environments, including high-frequency electromagnetic interference from other electrical equipment. Additionally, the minute eddies and fluctuations of the fluid within the pipe can also have an impact. These factors result in an uneven original electrical signal transmitted by the pressure sensor. Even after being converted into a digital signal by an analog-to-digital converter, the resulting series of pressure values ​​arranged over time will exhibit irregular, minute fluctuations.

[0049] In order to accurately extract the true trend of pressure changes from this signal with glitches, the controller sets up a data storage area in its internal memory that is similar to a continuous queue, namely a sliding window register array. The sliding window always retains multiple pressure data points collected sequentially within the most recently set time period, where the pressure data is in megapascals and the time period is preferably set to between 100 milliseconds and 500 milliseconds. Whenever a new pressure sample value arrives, it is placed at the end of the queue, while the oldest data point at the front of the queue is removed, thus maintaining the timeliness of the data within the window and ensuring that the window is always dynamically updated with a set of the latest discrete pressure samples.

[0050] Next, the controller selects the latest pressure value and a historical pressure value from a slightly earlier time, such as several milliseconds ago, from the data queue of the sliding window, and calculates the difference between these two pressure values, that is, the amount of pressure change during this time period; at the same time, it also calculates the difference between the corresponding time points of these two data points, that is, the time interval; then, it divides the amount of pressure change by the time interval, and the result is an average rate of change; this calculation process is mathematically approximated by solving the instantaneous rate of change of the pressure-time curve at the current position, that is, the slope of the tangent line at that point.

[0051] Through this calculation, the system's focus shifts from the absolute value of the pressure to the rate of pressure change, effectively eliminating relatively static background values ​​such as the static pressure of the pipeline foundation. This allows the system to keenly capture the transient characteristics of pressure rising or falling rapidly in a short period of time.

[0052] Based on the captured dynamic rise and fall rate of pressure, the system then switches to a dynamic anti-misjudgment evolution branch specific to the opening and closing transition state.

[0053] Specifically, when the real-time opening signal indicates that the main valve core 2 is in the opening-closing transition state, the controller obtains the opening change rate of the main valve core 2; generates a first preset slope threshold, which is positively correlated with the opening change rate and dynamically adjusted according to the action rate of the main valve core 2; compares the pressure change slope with the first preset slope threshold to filter transient water hammer pulses or pressure fluctuations generated by high-speed fluid impact.

[0054] The controller continuously monitors and determines the real-time angle position of the main valve core 2. By comparing the real-time opening signal with a preset angle range, it determines whether the main valve core 2 is in a small angle range where a strong throttling effect is likely to occur, i.e., the opening and closing transition range. This range is usually set to be within the range from the fully closed 0° position to the opening of about 5°.

[0055] It should be noted that when the main valve core 2 is in the transitional state between closing and opening, the flow channel is extremely narrow, and the fluid is violently squeezed and accelerated when passing through, which can easily generate strong transient pressure fluctuations, i.e., water hammer effect.

[0056] Once the system confirms that the angle of the main valve core 2 is in the opening and closing transition range, the system will continuously acquire the angle value of the main valve core 2 and calculate the change in angle within a very short time interval, thereby obtaining the instantaneous speed at which the main valve core 2 is closing or opening, i.e., the opening change rate. This opening change rate directly reflects the intensity of the valve action.

[0057] As we know from the principles of fluid mechanics, the faster and more violent the valve action, the more intense the disturbance to the fluid, and the higher the intensity and the sharper the peak value of the transient pressure pulse generated. Therefore, the dynamic threshold generation module inside the controller will adjust the first preset slope threshold used to judge whether the pressure is abnormally rising in real time according to the real-time calculated opening change rate of the main valve core 2. The faster the action speed, the higher the first preset slope threshold will be; the slower the action speed, the lower the first preset slope threshold will be.

[0058] The system compares the pressure change slope measured and calculated by the sensor with the first preset slope threshold dynamically generated based on the operating speed of the main valve core 2. Only when the measured pressure change slope not only exceeds the first preset slope threshold but also significantly breaks through the upper limit of the reasonable fluctuation range defined by the current operating speed will the system finally determine that this is not water hammer interference caused by normal valve operation, but a real abnormal pressure buildup has occurred inside the cavity, thus triggering subsequent defense actions.

[0059] It should be noted that the first preset slope threshold represents the upper limit of reasonable pressure fluctuation caused by fluid shock caused by the mechanical action of the valve core under the current opening change rate.

[0060] Specifically, the first preset slope threshold is generated. Its processing logic includes: inputting the extracted absolute value form of the opening change rate into the preset correlation model; scaling the absolute value form of the opening change rate based on the first preset system correlation coefficient, and superimposing the second preset system correlation coefficient as the basic compensation amount; outputting the scaled and compensated value as the first preset slope threshold, so as to realize the dynamic coupling between the judgment benchmark and the intensity of the mechanical action of the main valve core 2.

[0061] After acquiring the opening change rate of the main valve core 2, the controller takes its absolute value. Since the main valve core 2 is in a state of rapid opening or rapid closing, the rapid mechanical action will cause severe disturbance to the fluid and trigger pressure pulses. Therefore, the absolute value of the opening change rate can accurately characterize the severity of the action of the main valve core 2, and serve as the basis for the calculation of subsequent pressure fluctuation expectations.

[0062] After obtaining the absolute value representing the intensity of the action, the system will input it into a preset correlation model for calculation; the calculation model can be a simple linear proportional relationship or a more complex nonlinear relationship fitted based on experimental data.

[0063] The microprocessor retrieves a pre-set first preset system correlation coefficient from its underlying memory. The first preset system correlation coefficient comprehensively reflects a series of inherent physical characteristics of the current valve system, mainly including: the diameter of the pipe, the medium flowing in the pipe, such as the density of liquefied natural gas, and the flow regulation characteristic curve determined by the structure of the valve itself. These hardware attributes together determine how much pressure fluctuation may theoretically be caused when the main valve core 2 moves at a certain speed.

[0064] The microprocessor multiplies the first preset system correlation coefficient with the absolute value of the opening change rate mentioned above. The purpose of this multiplication operation is to proportionally amplify or reduce the basic action intensity, thereby obtaining a preliminary expected value of pressure fluctuation that matches the current physical conditions of the system.

[0065] However, considering that when the valve moves slowly at extremely low speeds, the absolute value of the rate of change of opening will be very small, and the initial threshold obtained by multiplying it may also approach zero; if this is used directly as the judgment standard, the system may generate false alarms due to minor environmental noise or normal fluctuations in the pressure sensor; to prevent this situation and ensure that the system still has stable anti-interference capability at low speeds, the model adds a second preset system correlation coefficient on top of this; the second preset system correlation coefficient represents the inherent background noise level of the entire measurement and control system, as well as the normal fluctuation range of static pressure that may exist in the pipeline. The system will use the second preset system correlation coefficient as a basic compensation quantity and add it to the result obtained from the previous multiplication operation; in this way, even if the main valve core 2 moves extremely slowly, the final dynamic threshold will not be lower than a reasonable bottom line value.

[0066] Through this series of coherent calculation steps, the controller transforms a speed value describing the speed of mechanical component movement into a dynamic reference standard for judging whether pressure changes are abnormal at the thermodynamic and fluid dynamic levels. This transformation process enables the system's judgment benchmark to intelligently adapt to different valve actuation intensities and specific working environments.

[0067] Specifically, when the real-time opening signal exceeds the set range of the opening and closing transition state, indicating that the main valve core 2 is in a normally open flow state, it is determined that the intermediate cavity does not have the conditions for sealing and pressure buildup, and the controller controls the bypass valve 3 to remain closed and enter the standby state.

[0068] The system continuously reads and monitors the valve opening signal fed back by the absolute encoder. The opening signal is fed back in the form of an angle value, indicating the current rotation position of the main valve core 2. When the angle value exceeds a preset critical value, such as 5 degrees, it indicates that the flow channel hole on the main valve core 2 has been connected to the inlet and outlet pipes at both ends of the valve, forming an open flow path.

[0069] At this point, the valve's central cavity is directly connected to the main pipeline system behind it through this flow path, and is no longer a closed space. Therefore, even if a small amount of ambient heat enters the central cavity, causing the internal residual medium to expand due to heat, the resulting additional volume or pressure will be released into the entire flowing fluid system through this open flow channel, rather than accumulating locally to form dangerous high pressure.

[0070] When the system confirms that the main valve core 2 has entered the normal flow state, the logic judgment module inside the controller will pause the execution of pressure detection calculation, such as calculating the pressure change slope and dynamic threshold comparison, and at the same time output a control signal to lock the servo-driven miniature electromagnetic bypass valve to ensure that it remains closed.

[0071] At this time, the system enters standby mode, only maintaining basic monitoring of the opening degree of the main valve core 2; when the opening degree signal falls back to the opening and closing transition range, the controller resumes the corresponding pressure detection and defense logic.

[0072] Example 3 In scenarios involving the accumulation of cryogenic liquid and continuous input of ambient heat, when the valve is closed, a portion of the cryogenic medium will inevitably be trapped in the central cavity of the valve body 1. When ambient heat is conducted in through the valve body 1, this portion of the medium will rapidly absorb heat and vaporize. This phase change in the central cavity will result in extremely high expansion pressure. If the pressure relief structure is blocked by ice or fails, it can easily lead to the rupture of the valve body 1 or the breaking of the fastening bolts. Therefore, this embodiment is a further improvement on the basis of Embodiment 1.

[0073] Reference Figures 1 to 2 As shown, specifically, the overpressure hazard is determined by combining the trend of the real-time temperature signal, including: when the real-time opening signal indicates that the main valve core 2 is in a fully closed steady state, the controller calculates the slope of the theoretical saturated vapor pressure change under the current temperature conditions based on the real-time temperature signal, and performs temperature compensation to generate a second preset slope threshold; when the pressure change slope exceeds the second preset slope threshold and the real-time temperature signal shows a continuous upward trend, it is determined that the medium phase change vaporization is occurring in the cavity, and there is a real overpressure hazard.

[0074] The explicit prerequisite for the system to enter the highest level of alert is that the valve opening signal continuously fed back by the absolute encoder stably indicates 0°, that is, the main valve core 2 has been fully rotated to the closed position, and the flow channel hole on it is completely misaligned with the valve body 1 channel, thereby forming a sealed cavity space between the valve seat that is completely isolated from the main pipeline; at this time, the cryogenic liquid medium trapped in this sealed space is in an extremely unstable state; since the valve body 1 is always exposed to the external ambient temperature, ambient heat will be continuously and inevitably transferred to the internal cavity through the valve body 1.

[0075] The controller continuously monitors the temperature inside the cavity by using a low-temperature probe installed in the cavity of valve body 1. By analyzing the trend of temperature change over time, it calculates the rate of temperature increase and determines whether heat is being continuously and stably transferred into the cavity.

[0076] In this state, the system calls its internally stored and set core calculation rules, which are based on the physical laws of the gas-liquid phase change of the transported medium itself. Specifically, they are based on the thermodynamic equations describing the relationship between saturated vapor pressure and temperature. These thermodynamic equations include, but are not limited to, the Clausius-Clapeyron equation. These laws are solidified into data tables or calculation formulas and stored in the controller.

[0077] The microprocessor uses these rules, combined with the current real-time measured temperature value and the calculated rate of temperature rise, to perform reverse calculations to determine a theoretical slope of saturated vapor pressure change, that is, how quickly the internal pressure of the medium would theoretically increase under the current thermodynamic conditions if a phase change occurred.

[0078] It should be noted that, in order to eliminate the interference of measurement errors, the controller introduces an engineering safety factor greater than 1 to compensate for the slope of the theoretical saturated vapor pressure change, thereby generating a second preset slope threshold that is slightly higher than the theoretical value.

[0079] When the slope of the real-time pressure change measured and calculated by the pressure sensor exceeds the second preset slope threshold, and the temperature inside the cavity is confirmed to be in a continuous rising process based on the monitoring data of the temperature probe, the system will determine that a "pressure build-up" phenomenon is indeed occurring in the sealed space of the cavity, rather than a false alarm caused by sensor failure or random interference, and thus trigger the pressure relief action.

[0080] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-pressure ball valve with large temperature variation, comprising a valve body and a main valve core disposed within the valve body, characterized in that, It also includes sensor components, actuator components, and controllers; The sensor assembly is used to collect pressure signals, temperature signals, and the opening signal of the main valve core within the valve body cavity. The actuation component includes a bypass valve that communicates with the cavity of the valve body; The controller is electrically connected to the sensor assembly and the bypass valve, and the controller is configured to: Acquire the real-time opening signal of the main valve core, the real-time pressure signal and the real-time temperature signal in the middle cavity; The operating state of the main valve core is determined based on the real-time opening signal, and the pressure change slope of the real-time pressure signal is calculated. Determine whether the action state is in an open / close transition state or a fully closed steady state, and compare the corresponding preset slope threshold with the pressure change slope based on the action state, and combine the trend of the real-time temperature signal to determine the overpressure risk. Perform the corresponding pressure relief action. If an overpressure risk is detected, control the bypass valve to open to relieve pressure. When the real-time opening signal indicates that the main valve core is in the opening-closing transition state, the opening change rate of the main valve core is obtained; Input the extracted absolute value form of the opening change rate into the preset correlation model; The absolute value form of the opening change rate is scaled proportionally based on the first preset system correlation coefficient, and the second preset system correlation coefficient is superimposed as the basic compensation amount. The output scaled and compensated value is used as the first preset slope threshold to achieve dynamic coupling between the judgment benchmark and the intensity of the mechanical action of the main valve core, and the pressure change slope is compared with the first preset slope threshold. When the real-time opening signal indicates that the main valve core is in a fully closed steady state, the theoretical saturated vapor pressure change slope under the current temperature conditions is calculated in combination with the real-time temperature signal, and temperature compensation is performed to generate a second preset slope threshold. When the slope of the pressure change exceeds the second preset slope threshold and the real-time temperature signal shows a continuous upward trend, it is determined that the medium is undergoing phase change and vaporization in the cavity, indicating a real overpressure hazard.

2. The high-pressure ball valve with large temperature variation according to claim 1, characterized in that, When the real-time opening signal exceeds the set range of the opening and closing transition state, indicating that the main valve core is in a normally open flow state, it is determined that the middle cavity does not have the conditions for sealing and pressure buildup, and the controller controls the bypass valve to remain closed and enter the standby state.

3. The high-pressure ball valve with large temperature variation according to claim 1, characterized in that, Controlling the opening of the bypass valve for pressure relief includes: The controller outputs a pulse width modulation signal to the bypass valve; The bypass valve is opened in a high-frequency, minute manner by controlling the pulse width modulation signal, so that the high-pressure medium accumulated in the middle cavity can be smoothly discharged to the downstream through the bypass guide channel and independent pipeline.

4. A high-pressure ball valve with large temperature variation according to claim 3, characterized in that, The controller continuously monitors the real-time pressure signal in the middle cavity until the real-time pressure signal in the middle cavity falls below the set safety baseline, at which point the bypass valve is automatically closed.

5. A high-pressure ball valve with large temperature variation according to claim 1, characterized in that, The calculation logic for the slope of pressure change in real-time pressure signals includes: Input discrete pressure samples collected continuously over a time series and calculate the ratio of the pressure difference between adjacent time points to the time difference. This ratio is output as the current pressure change slope to represent the dynamic rate of increase and decrease of pressure within the cavity.

6. A high-pressure ball valve with large temperature variation according to claim 1, characterized in that, The sensor assembly includes a high-pressure resistant thin-film pressure sensor and a low-temperature temperature probe installed inside the valve body cavity, and also includes an absolute encoder connected to the top of the valve stem. The bypass valve includes a PWM micro-controlled electromagnetic bypass valve. The inlet end of the PWM micro-controlled electromagnetic bypass valve is connected to the middle cavity through a flow guide channel, and its pressure relief outlet end is connected to the downstream pipeline of the valve or the discharge and recovery system via an independent pipeline.

7. A high-pressure ball valve with large temperature variation according to claim 6, characterized in that, The sensor leads of the high-pressure resistant thin-film pressure sensor and the low-temperature temperature probe are covered with a low thermal conductivity composite material.

Images