Low-temperature ball valve

Abstract

The invention discloses a low-temperature ball valve. The low-temperature ball valve comprises a processor, a memory and an execution mechanism, the heat distribution optimization control method comprises the steps that temperature distribution data of the low-temperature ball valve are collected, and a ball valve surface temperature distribution model is established; energy needed by heating is calculated according to the heat transfer basic equation; calculating a heat transfer rate based on a convective heat transfer equation; determining an optimal heat distribution strategy according to the spatial heat distribution optimization objective function; controlling system heat balance based on the dynamic heat balance equation; minimizing system energy consumption in combination with an energy consumption optimization objective function; and the rotating circular ring is controlled to move through the executing mechanism, so that the heating system dynamically heats the surface of the low-temperature ball valve according to the optimal heat distribution strategy, and frosting is prevented. The low-temperature ball valve has the following beneficial effects that through dynamic heat distribution and thermodynamic parameter optimization, uniform heating of the surface of the ball valve is achieved, the frosting phenomenon is effectively prevented, meanwhile, energy consumption is minimized, the reliability of the low-temperature ball valve is remarkably improved, and the service life of the low-temperature ball valve is remarkably prolonged.

Description

Technical Field

[0001] The present invention relates to the field of industrial control, and more specifically, to a cryogenic ball valve suitable for use in applications requiring frost protection, such as cryogenic piping systems, liquefied natural gas equipment, and cryogenic chemical production lines. This system achieves uniform heating of the ball valve surface through precise control of dynamic heat distribution and optimization of thermodynamic parameters, effectively preventing frost formation while minimizing energy consumption and significantly improving the reliability and service life of the cryogenic ball valve. Background Art

[0002] Cryogenic ball valves are core components in industrial fluid control systems, widely used to transport and control cryogenic media. However, in real-world operating environments, cryogenic ball valves often face severe frost problems. When the temperature of the cryogenic medium conveyed within the ball valve is significantly lower than the ambient temperature, water vapor in the surrounding air condenses into droplets upon contact with the cold surface. These droplets then freeze into frost as the temperature drops further. This frosting phenomenon negatively impacts the proper operation of the cryogenic ball valve in various ways.

[0003] The most direct impact of frost is increased friction in ball valve operations. Frost gradually accumulates and penetrates the sealing surfaces, stuffing box, and other moving parts of the ball valve, significantly increasing mechanical friction. This can make opening and closing operations difficult, and in severe cases, can even cause the valve to completely seize. Furthermore, continuous frost-defrost cycles accelerate the aging and wear of sealing materials, reducing sealing performance and increasing the risk of leakage. From a safety perspective, falling frost can also make the operating area slippery, increasing the risk of workers slipping and posing a potential safety hazard.

[0004] Traditional anti-frost methods focus on two main approaches: first, material modification and surface treatment, which reduce frost by altering surface wettability and microstructure; and second, the addition of auxiliary heating devices such as insulation or heating cables. However, each of these methods has limitations. Surface treatment typically only delays frost formation and is difficult to maintain over long-term operation. Traditional insulation and heating cables often suffer from uneven heat distribution, low energy efficiency, and difficult maintenance. Especially on the surface of a shaped ball valve, uneven heat distribution can cause some areas to overheat while others remain frosted. This not only wastes energy but can also affect the temperature stability of the low-temperature medium within the ball valve.

[0005] Therefore, there is an urgent need to develop a low-temperature ball valve anti-frost system that can achieve uniform heat distribution, efficient energy utilization and intelligent control capabilities under dynamic working conditions to solve the existing problems. Summary of the Invention

[0006] The present invention provides a cryogenic ball valve, which adopts dynamic heating and precise control methods determined by thermodynamics to achieve uniform temperature distribution on the surface of the ball valve and efficient anti-frost effect while minimizing energy consumption.

[0007] The core of this invention is the integration of thermodynamic principles and control algorithms. By building a comprehensive heat transfer model and temperature distribution optimization strategy, a dynamically rotating heating device is used to uniformly heat the ball valve surface, avoiding the hot and cold spots caused by traditional static heating methods. This system not only prevents frost formation but also strikes a balance between energy efficiency and ball valve performance, ensuring that the low-temperature medium transported within is not significantly affected.

[0008] Specifically, the anti-frost control system of the present invention includes a processor, memory, and an actuator. When executed by the processor, a computer program stored in the memory implements a series of thermal distribution optimization control functions. The system first collects temperature distribution data of a cryogenic ball valve and establishes a ball valve surface temperature distribution model (T(r, θ, t), where r represents the radial coordinate, θ represents the angular coordinate, and t represents time). Based on this temperature distribution model, the system dynamically analyzes and predicts the temperature field on the ball valve surface.

[0009] The system calculates the heating energy required based on the fundamental heat transfer equation: Q = m·c·ΔT, where Q represents the amount of heat transferred, m represents the mass of the heated medium, c represents the specific heat capacity, and ΔT represents the temperature change. This equation, a fundamental law of thermodynamics, determines the amount of heat required to raise a specified mass of a medium (primarily air in this system) to a specific temperature. By accurately calculating the heat requirement, the system avoids energy waste and achieves efficient heating.

[0010] To accurately assess heat transfer efficiency, the system calculates the heat transfer rate using the convective heat transfer equation q = h·A·ΔT, where q represents the heat transfer rate, h represents the convective heat transfer coefficient, A represents the heated surface area, and ΔT represents the temperature difference between the hot air and the ball valve surface. The convective heat transfer coefficient h is a key parameter, influenced by a variety of factors, including fluid properties, flow conditions, and surface geometry. This system optimizes fan speed and airflow guidance to improve the convective heat transfer coefficient and enhance heat transfer efficiency.

[0011] The core optimization goal of the system is to achieve uniform distribution of ball valve surface temperature. To this end, the spatial heat distribution optimization objective function min(max(T surface )-min(T surface This function minimizes the difference between the highest and lowest surface temperatures, ensuring uniform heat distribution and preventing localized frost or overheating. By dynamically adjusting the heating strategy, the system continuously optimizes temperature uniformity across the ball valve surface.

[0012] In order to maintain the thermal equilibrium state of the system, the control system applies the dynamic thermal balance equation H input -H loss =H stored , where H input Indicates the input heat, H loss Represents heat loss, H stored Represents the heat stored in the ball valve body. This equation determines how the system maintains appropriate heat input under different environmental conditions, neither causing frost due to low temperatures nor affecting the low-temperature medium inside the ball valve due to high temperatures.

[0013] While meeting the anti-frost effect, the system is also committed to reducing energy consumption, introducing the energy consumption optimization objective function min(∫[t=0 to T][P heat (t)+P fan (t)]dt). This function aims to minimize the total energy consumption of the system during the operation cycle, where P heat (t) represents the power of the heating element at time t, P fan (t) represents the fan power at time t. By dynamically adjusting the power output of each component, the system achieves efficient energy utilization while ensuring anti-frost effect.

[0014] The system's actuators primarily consist of rotating rings, heating elements, and fans, which perform specific anti-frost operations based on processor instructions. The rotating ring is the core device for achieving dynamic heat distribution, driving the heat source to rotate across the ball valve surface, ensuring even heat distribution to all parts of the valve. The system also uses the dynamic temperature field equation:

[0015] T(r,θ,t)=T amb +(Q / (4πλr))·e^(-(r 2 ) / (4α(t-τ)))·f(θ-ωt) to calculate the instantaneous temperature distribution on the ball valve surface, where T amb represents the ambient temperature, Q represents the heat source intensity, λ represents the material thermal conductivity, α represents the thermal diffusivity, τ represents the thermal hysteresis time, f(θ-ωt) represents the heat source distribution function that varies with the rotation angle, and ω represents the angular velocity of rotation. The above equation comprehensively considers factors such as heat source movement, heat conduction, and time delay, and can accurately describe the temperature evolution of the ball valve surface under dynamic heating conditions.

[0016] The present invention also provides a precise control method for the power of the heating wire, based on the thermal power equation P heat ≥(h·A·(T safe -T amb )) / η transfer , where P heat Indicates the required thermal power, h indicates the comprehensive heat transfer coefficient, A indicates the surface area of ​​the ball valve, Tsafe Indicates the safe temperature to prevent frost, T amb represents the ambient temperature, η transfer The above equation ensures that the system provides sufficient thermal power to maintain the ball valve surface above a safe temperature, effectively preventing frost formation.

[0017] The rotation speed of the rotating ring has a great influence on the uniformity of heat distribution. This system uses the formula ω optimal =√(2·α·ΔT / (r·ρ·c)) to determine the optimal angular velocity, where ω optimal represents the optimal angular velocity, α represents the thermal diffusion coefficient, ΔT represents the allowable temperature difference, r represents the ball valve radius, ρ represents the air density, and c represents the specific heat capacity of air. The above formula is based on thermal diffusion and takes into account material properties and geometric parameters to ensure that the rotating ring operates at the most appropriate speed for optimal heat distribution.

[0018] In order to adapt to changes in the environment and working conditions, the system is also equipped with a temperature feedback control mechanism. According to the PID control equation P heat =P base +K p (T target -T actual )+K i ∫(T target -T actual )dt dynamically adjusts the heating power, where P heat Indicates heating power, P base Indicates basic power, K p Represents the proportionality coefficient, K i Indicates the integral coefficient, T target Indicates the target temperature, T actual This closed-loop control method enables the system to respond to temperature changes in real time and maintain a stable anti-frost effect.

[0019] When the ball valve reaches thermal equilibrium, the system passes the ball valve surface thermal equilibrium equation T surface =T env +(P heat ·η transfer ) / (h·A) to calculate the steady-state temperature, where T surface Indicates the surface temperature of the ball valve, T env Indicates the ambient temperature, P heat Indicates heating power, η transfer represents the heat transfer efficiency, h represents the comprehensive heat transfer coefficient, and A represents the surface area of ​​the ball valve. This equation reveals the quantitative relationship between surface temperature and parameters such as heating power and heat transfer efficiency, providing support for the long-term stable operation of the system.

[0020] The system also introduces the concept of anti-frost safety factor, through the formula S=((T surface -T frost ) / (T frost -T amb ))·((T max -T surface ) / (T max -T optimal )) is calculated, where S represents the safety factor, T surface Indicates the actual surface temperature, T frost Indicates the frost temperature, T amb Indicates the ambient temperature, T max Indicates the maximum allowable temperature, T optimal Indicates the optimal operating temperature. The safety factor takes into account both the anti-frost effect and the temperature safety margin. It ensures that the surface temperature is sufficiently above the frost point while also preventing excessive temperatures from affecting the low-temperature medium inside the ball valve. The higher the safety factor, the more stable and reliable the system operation.

[0021] In addition, the present invention also proposes a low-temperature ball valve anti-frost method based on zone heating, which divides the ball valve surface into multiple heating zones and calculates the heat demand for each zone: Q total =∑(i=1 to n)(m i c i ΔT i ), where n represents the number of regions, m i represents the air quality received by each area, c i represents the specific heat capacity of air, ΔT i Indicates the required temperature rise for each zone. This zoned heating strategy can more accurately distribute heat, provide differentiated heating based on the actual needs of each zone, and further improve energy efficiency.

[0022] The method is also based on the airflow dynamics equation A total =n·π·r hole 2 =Q air / ν exit Design the air hole layout of the heating system, where A total represents the total area of ​​all pores, n represents the number of pores, r hole represents the pore radius, Q air represents the air flow rate, ν exit The above equation ensures that the number and size of the air holes match the required air flow, optimizing air distribution and heat transfer.

[0023] The control of the rotating ring follows the angular velocity equation ω ring =(n motor ·Zgear ) / Z ring , where ω ring represents the angular velocity of the rotating ring, n motor Indicates the motor speed, Z gear Indicates the number of teeth on the hollow gear, Z ring This equation describes the conversion relationship between the motor speed and the actual rotation speed of the ring, providing a basis for precise control of the system.

[0024] Finally, the system uses the energy efficiency ratio formula η system =(ΔT surface ·A) / (∫[0 to T]P(t)dt) to evaluate the anti-frost efficiency, where η system Indicates the system energy efficiency ratio, ΔT surface represents the surface temperature rise, A represents the heated surface area, and P(t) represents the total power consumption of the system at time t. These indicators reflect the heating effect produced per unit of energy consumption and are important parameters for measuring the energy efficiency of the system.

[0025] Through the above core heat distribution optimization control strategy and precise mathematical model, the present invention overcomes the limitations of traditional anti-frost, achieves uniform heating and efficient anti-frost on the surface of low-temperature ball valves, while reducing energy consumption, extending equipment service life, and improving system safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of a cryogenic ball valve of the present invention.

[0027] Figure 2 It is a schematic diagram of the rotating ring and the heating mechanism in the present invention.

[0028] Figure 3 It is a functional module block diagram of the control system in the present invention.

[0029] Figure 4 This is a flow chart of the anti-frost control method based on dynamic heat distribution of the present invention.

[0030] Figure 5 It is a comparison diagram of the surface temperature distribution of the ball valve before and after optimization in the present invention.

[0031] Figure 6 This is a comparison chart of the anti-frost effect of the present invention under different ambient temperature conditions.

[0032] Figure 7 This is a comparison chart of the energy consumption of the system of the present invention and the traditional heating method.

[0033] Figure 8 It is a three-dimensional distribution diagram of the dynamic temperature field under the working conditions of the present invention. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0035] like Figure 1 、 Figure 2 As shown, a cryogenic ball valve of the present invention mainly includes a ball valve body 12, a rotating ring 4, a connecting column 6, a heating mechanism and a driving mechanism. The ball valve body 12 is a conventional cryogenic ball valve structure, with a joystick 5 connected to the top. The rotating ring 4 is connected to the ball valve body 12 through the connecting column 6, forming a structural arrangement that can move relative to each other. The heating mechanism is installed on the rotating ring 4 and includes a square shell 3, a heating wire 25, a fan 26 and a nozzle 2. The driving mechanism includes a motor 11, a gear ring 9 and a hollow gear 10, which is used to drive the rotating ring 4 to rotate around the ball valve body 12. The entire system also includes a control unit (not shown in the figure), which is composed of a processor, a memory and related sensors, and is responsible for the intelligent control and parameter optimization of the system.

[0036] like Figure 2 As shown, the inner wall of the rotating ring 4 is provided with an annular groove 13, which is designed to slide with the arc-shaped block 14 on the connecting column 7, achieving stable rotation of the rotating ring 4. The heating mechanism is fixed to the outer wall of the rotating ring 4 and includes a square shell 3 and a nozzle 2. The square shell 3 houses a heating wire 25 and a fan 26. The heating wire 25 converts electrical energy into thermal energy, while the fan 26 generates airflow to transfer heat to the nozzle 2. Multiple air holes 30 are evenly distributed on the outer wall of the nozzle 2. Hot air is sprayed uniformly through these holes onto the surface of the ball valve body 12, creating a dynamic and uniform heat distribution.

[0037] like Figure 3 、 Figure 4 As shown in the figure, the system's operating principle is based on thermodynamics and precise temperature control algorithms. First, a temperature sensor collects temperature distribution data on the ball valve surface and establishes a temperature distribution model T(r,θ,t). Based on this model, the system calculates the required heat and determines the optimal heat distribution strategy. The heating wire 25 generates heat, and the fan 26 drives the heated airflow, which is then evenly sprayed onto the ball valve surface through the air holes 30 of the nozzle 2. Simultaneously, the motor 11 drives the rotating ring 4 through the gear ring 9 and hollow gear 10, causing the heating device to move around the ball valve body 12, achieving dynamic and uniform heating. The system continuously monitors temperature changes and adjusts the heating power and rotation speed based on feedback to ensure optimal anti-frost effect and energy efficiency.

[0038] The heat transfer process follows the basic laws of thermodynamics. When the heating wire is energized to generate heat, its power can be expressed as P=V·I=V 2 / R=I 2 R, where V is voltage, I is current, and R is resistance. The above power is converted into heat energy, following the heat power generation equation Qgen =η·P elect , where η is the energy conversion efficiency, typically between 0.95 and 0.98. The generated heat is transferred to the air through forced convection from the fan. The required heat is determined by the equation Q = m·c·ΔT, where m is the air mass, c is the specific heat capacity of air (approximately 1005 J / (kg·K)), and ΔT is the desired temperature rise.

[0039] In practical applications, the air flow rate is related to the fan parameters and satisfies the relationship Q air =k·ω·D³, where k is the fan characteristic coefficient (related to the fan structure), ω is the fan angular velocity, and D is the fan diameter. To ensure sufficient airflow through the pores, the total area of ​​the pores must meet A total =n·π·r hole 2 =Q air / ν exit , where n is the number of pores, r hole is the pore radius, ν exit is the desired airflow outlet velocity. Practice has shown that when the airflow velocity is within the range of 5-10m / s, it can provide good heat transfer effect without generating excessive noise.

[0040] The rotation speed of the rotating ring has a great influence on the uniformity of heat distribution. The optimal angular velocity satisfies ω optimal =√(2·α·ΔT / (r·ρ·c)), where α is the thermal diffusion coefficient (related to the ball valve material), ΔT is the allowable temperature difference (usually controlled within the range of 2-5°C), r is the ball valve radius, ρ is the air density, and c is the air specific heat capacity. For example, for stainless steel (α is about 4×10 -6 m 2 / s), a ball valve with a radius of 100mm, and an allowable temperature difference of 3℃, the calculated optimal angular velocity is about 0.09rad / s, which is equivalent to about 0.86 revolutions per minute. In practical applications, the angular velocity of the rotating ring is determined by the gear transmission relationship ω ring =(n motor ·Z gear ) / Z ring Control, where n motor is the motor speed, Z gear is the number of teeth of the hollow gear, Z ring is the number of ring teeth.

[0041] The determination of thermal power is the core of system design. To ensure effective anti-frost, the thermal power must meet P heat ≥(h·A·(T safe -T amb )) / η transfer , where h is the comprehensive heat transfer coefficient (usually 5-25W / (m2 K) range, depending on the air flow velocity and surface conditions), A is the surface area of ​​the ball valve, T safe To prevent frost from forming, set the safe temperature (usually 3-5°C higher than the dew point). amb is the ambient temperature, η transfer is the heat transfer efficiency (usually between 0.7 and 0.9). For example, for a surface area of ​​0.2 m 2 For a ball valve, under the condition that the ambient temperature is 5℃ and the safety temperature needs to reach 15℃, assuming h is 15W / (m 2 K), η transfer If the value is 0.8, the minimum thermal power required is about 75W.

[0042] The temperature control of the system adopts PID control strategy. According to equation P heat =P base +K p (T target -T actual )+K i ∫(T target -T actual )dt dynamically adjusts thermal power, where P base For basic power (usually set to 80-90% of the minimum thermal power), K p is the proportionality coefficient (usually between 1.0-2.5), K i is the integration coefficient (usually between 0.01-0.1), T target is the target temperature, T actual This control method can quickly respond to temperature changes while avoiding power fluctuations caused by over-adjustment.

[0043] Under steady-state conditions, the surface temperature of the ball valve can be calculated by the heat balance equation T surface =T env +(P heat ·η transfer ) / (h·A) prediction, where T env is the ambient temperature, P heat is the heating power, η transfer is the heat transfer efficiency, h is the comprehensive heat transfer coefficient, and A is the ball valve surface area. The above equation reveals a linear relationship between surface temperature and heating power, providing a basis for system design. In practical applications, the cooling effect of the low-temperature medium inside the ball valve must also be considered. Therefore, a 10-20% thermal power margin is typically added to the calculation.

[0044] The operational safety of the system is determined by the safety factor S=((T surface -T frost ) / (T frost -T amb))·((T max -T surface ) / (T max -T optimal ))Evaluation, where T surface is the actual surface temperature, T frost is the frost temperature (i.e. the dew point temperature of the current environment), T amb is the ambient temperature, T max is the maximum allowable temperature (depending on the properties of the medium inside the ball valve), T optimal The optimal operating temperature (usually dew point plus approximately 5°C). A larger safety factor, S, indicates a safer and more reliable system. Practical experience shows that when S ≥ 1.5, the system can operate stably under various operating conditions, effectively preventing frost.

[0045] In order to further improve energy efficiency, the system adopts a zone heating strategy, which divides the ball valve surface into multiple heating areas and calculates the heat demand Q for each area. total =∑(i=1 to n)(m i c i ΔT i ). Where n is the number of regions, m i The air quality received by each area, c i is the specific heat capacity of air, ΔT i The required temperature rise for each zone.

[0046] In addition, the system also optimizes the objective function min(∫[t=0 to T][P heat (t)+P fan (t)]dt) minimizes energy consumption, where P heat (t) is the power of the heating element, P fan (t) is the fan power. In practical applications, the system typically dynamically adjusts the operating status of the heating wire and fan while meeting anti-frost requirements. For example, the power may be appropriately reduced when the ambient temperature is high, or increased when the humidity is high, to achieve the best energy efficiency ratio.

[0047] like Figure 5 As shown, the dynamic temperature field distribution of the system can be expressed by equation: T(r,θ,t)=T amb +(Q / (4πλr))·e^(-(r 2 ) / (4α(t-τ)))·f(θ-ωt) is accurately described, where T ambis the ambient temperature, Q is the heat source intensity, λ is the material thermal conductivity, α is the thermal diffusivity, τ is the thermal hysteresis time, f(θ-ωt) is the heat source distribution function that varies with the rotation angle, and ω is the angular velocity. The above equation comprehensively considers factors such as heat source movement, heat conduction, and time delay, and can accurately predict the temperature evolution of the ball valve surface under dynamic heating conditions. In practical applications, this equation can be solved numerically to construct a temperature distribution map of the ball valve surface and determine the optimal heating strategy.

[0048] Figure 6 Shown is a comparison diagram of the anti-frost effect of the present invention under different ambient temperature conditions.

[0049] Figure 7 Shown is a comparison chart of the energy consumption of the system of the present invention and the traditional heating method.

[0050] Figure 8 Shown is a three-dimensional distribution diagram of the dynamic temperature field under the working conditions of the present invention.

[0051] The application effects of the present invention are described in detail below through specific embodiments: Example 1: Application in liquefied natural gas (LNG) transportation system In the cryogenic piping system of an LNG terminal, DN200 cryogenic ball valves frequently frosted during operation, compromising operational safety. Applying the anti-frost control system presented in this invention, the system first collected surface temperature distribution data for the ball valves and found that the surface temperature ranged from -15°C to -8°C, significantly lower than the local ambient temperature (approximately 10°C) and the dew point (approximately 5°C). Based on the temperature distribution model, the system calculated the required heating power to be approximately 200W.

[0052] The system utilizes a 150mm diameter rotating ring, equipped with a 6kW heating coil and a 120mm diameter fan. Thirty-six 3mm diameter air holes are evenly distributed on the nozzle. According to the optimal angular velocity formula, the ideal rotational speed of the rotating ring is 1.2 revolutions per minute. After startup, the system continuously monitors the surface temperature of the ball valve and dynamically adjusts the heating power using a PID control algorithm. After approximately 10 minutes of heating, the surface temperature of the ball valve rises to a uniform 8-10°C, successfully preventing frost formation.

[0053] Long-term operational data shows that the system's average power consumption is approximately 180W, approximately 40% lower than traditional heating cable solutions. The safety factor, S, remains within the range of 1.8-2.2, demonstrating a strong safety margin. Especially during seasonal fluctuations in ambient temperature, the system automatically adjusts parameters through an adaptive control algorithm to maintain stable anti-frost performance.

[0054] Example 2: Application in low-temperature chemical production line A regulating ball valve in a low-temperature reaction system at a chemical plant was experiencing operational failure due to frost, impacting production safety. Applying the proposed system, the ball valve's geometric characteristics and operating environment were analyzed in detail, leading to the development of an accurate heat transfer model. With an ambient temperature of 15°C and a humidity of 75%, the calculated dew point was approximately 10.5°C, while the lowest ball valve surface temperature was only 4°C.

[0055] According to the thermal power equation P heat ≥(h·A·(T safe -T amb )) / η transfer Calculate the required thermal power. For this ball valve, the surface area A is approximately 0.15m 2 , the comprehensive heat transfer coefficient h is 20W / (m 2 ·K), safety temperature T safe Set to 14℃ (3.5℃ higher than the dew point temperature), the ambient temperature T amb At 15°C, the heat transfer efficiency η transfer is 0.85, and the required thermal power is calculated to be approximately 140W.

[0056] The system is equipped with a 180W heating wire, the diameter of the rotating ring is 120mm, and the rotation speed is determined by the formula ω optimal =√(2·α·ΔT / (r·ρ·c)) The optimal speed is 1.5 revolutions per minute. At the same time, the nozzle is designed with 24 air holes with a diameter of 3.5mm. According to the airflow dynamics equation A total =n·π·r hole 2 =Q air / ν exit Optimize to ensure uniform airflow distribution and maximize heat transfer efficiency.

[0057] After the system is put into use, the temperature distribution on the ball valve surface is monitored in real time through the temperature sensor network, and the dynamic temperature field equation is used: T(r,θ,t)=T amb +(Q / (4πλr))·e^(-(r 2 ) / (4α(t-τ)))·f(θ-ωt) predicts temperature changes under different heating strategies. The PID controller dynamically adjusts the heating power and rotation speed based on the feedback data to maintain the ball valve surface temperature within the range of 13-15°C, with a uniformity of less than 1.5°C.

[0058] Long-term operation data shows that the system energy efficiency ratio η system =(ΔT surfaceA) / (∫[0 to T]P(t)dt) is approximately 35% higher than traditional fixed heating systems, while also providing more stable and reliable anti-frost performance. Especially during the rainy season, when humidity fluctuates significantly, the system automatically adjusts its anti-frost strategy based on the real-time dew point temperature, ensuring a consistently safe operating state.

[0059] Example 3: Application in oil pipeline systems in extremely cold regions In a northern oil pipeline system, the ambient temperature often drops below -30°C. Conventional cryogenic ball valves not only face severe frost problems but also the risk of freezing. The system of the present invention is specially optimized for extreme environmental conditions.

[0060] The system first collected comprehensive environmental parameters and ball valve operating status data to develop a model that incorporates heat transfer characteristics under extremely low temperature conditions. Although the air humidity in extremely low temperatures is low, the significant difference between the ball valve surface temperature and the ambient temperature (the medium temperature inside the ball valve is approximately 6°C, while the ambient temperature can reach -35°C) still poses a risk of condensation and frost.

[0061] Based on a safe temperature calculation formula and heat transfer model, the system determined the required heating power to be 320W. Considering the increased heat loss caused by extremely cold environments, the system is equipped with a 400W heating wire and employs enhanced insulation. The rotating ring has a diameter of 180mm, and the rotation speed calculated using the optimal angular velocity formula is 2.0 revolutions per minute, ensuring uniform heating even in extreme conditions.

[0062] The system also adopts a zone heating strategy. According to the formula Q total =∑(i=1 to n)(m i c i ΔT i ) calculates the heat demand of each area, divides the ball valve surface into five heating zones, and distributes heat in a targeted manner. In particular, the heat allocation to the bottom area of ​​the ball valve, which is prone to frost, has been increased by about 20%.

[0063] After the system is started, the ball valve surface heat balance equation T surface =T env +(P heat ·η transfer ) / (h·A) predicts steady-state temperature and compares it with actual measured values ​​to optimize control parameters. Under stable operation, the ball valve surface temperature remains within a range of -5°C to -2°C. While lower than ambient temperature, it is significantly higher than the dew point (approximately -38°C), preventing frost and freezing.

[0064] The safety factor of the system is given by the equation S=((T surface -T frost ) / (Tfrost -T amb ))·((T max -T surface ) / (T max -T optimal )) calculated to be approximately 2.5, demonstrating the system's high reliability even under the most extreme conditions. Energy consumption monitoring data shows that while meeting anti-frost requirements, the system's average power consumption is approximately 30% lower than that of traditional heating cable solutions, resulting in significant energy cost savings over the long term.

[0065] The above examples demonstrate that the cryogenic ball valve of the present invention, through precise thermodynamic calculations and dynamic optimization control, can provide efficient and reliable anti-frost protection in a variety of industrial environments and conditions. The system's core advantage lies in achieving uniform heating of the ball valve surface, avoiding the hot and cold spots associated with traditional static heating methods. Furthermore, intelligent algorithms optimize energy utilization, reducing operating costs. This system is suitable for anti-frost protection of various cryogenic ball valves and has broad industrial application prospects.

[0066] It should be noted that the above embodiments are intended only to illustrate the solutions of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications and variations may be made to the present invention without departing from the solutions and scope of protection of the present invention. For example, the heat distribution algorithm may be adjusted, feedback control parameters may be optimized, and different heating element layouts may be employed based on specific application requirements. Such variations and modifications are considered to fall within the scope of protection of the present invention.

Claims

1. A cryogenic ball valve, characterized in that: include: A processor, a memory, and an execution mechanism, wherein the memory stores a computer program, and when the computer program is executed by the processor, the computer program realizes heat distribution optimization control, including: Collecting temperature distribution data of the cryogenic ball valve and establishing a surface temperature distribution model of the ball valve; Calculate the energy required for heating based on the basic heat transfer equation; Calculate heat transfer rate based on convection heat transfer equation; Determine the optimal heat distribution strategy based on the spatial heat distribution optimization objective function to make the surface temperature of the ball valve evenly distributed; Control system thermal balance based on dynamic thermal balance equation; Combined with the energy consumption optimization objective function to minimize the system energy consumption; The actuator controls the movement of the rotating ring, so that the heating system dynamically heats the surface of the low-temperature ball valve according to the optimal heat distribution strategy to prevent frost formation.

2. A cryogenic ball valve according to claim 1, characterized in that: The temperature distribution model is T(r,θ,t), where r is the radial coordinate, θ is the angular coordinate, and t is time; The basic equation for heat transfer is Q = m·c·ΔT, where Q is the amount of heat transferred, m is the mass of the heated medium, c is the specific heat capacity, and ΔT is the temperature change; The convective heat transfer equation is q = h·A·ΔT, where q is the heat transfer rate, h is the convective heat transfer coefficient, A is the heated surface area, and ΔT is the temperature difference; The objective function of spatial heat distribution optimization is min(max(T surface )-min(T surface )); The dynamic heat balance equation is H input -H loss =H stored ; Among them H input is the input heat, H loss is the heat loss, H stored To store heat; The energy consumption optimization objective function is min(∫[t=0 to T][P heat (t)+P fan (t)]dt); where P heat (t) is the power of the heating element, P fan (t) is the fan power.

3. A cryogenic ball valve according to claim 2, characterized in that: The dynamic heat distribution optimization control further includes: Through the dynamic temperature field equation: T(r,θ,t)=T amb +(Q / (4πλr))·e^(-(r 2 ) / (4α(t-τ)))·f(θ-ωt) to calculate the temperature distribution on the ball valve surface, where T amb is the ambient temperature, Q is the heat source intensity, λ is the thermal conductivity of the material, α is the thermal diffusivity, τ is the thermal hysteresis time, f(θ-ωt) is the heat source distribution function that changes with the rotation angle, and ω is the angular velocity of rotation.

4. A cryogenic ball valve according to claim 2, characterized in that: The power control of the heating wire is based on the following thermal power equation: P heat ≥(h·A·(T safe -T amb )) / η transfer Among them, P heat is the required thermal power, h is the comprehensive heat transfer coefficient, A is the surface area of ​​the ball valve, T safe To prevent frost, the safe temperature is T amb is the ambient temperature, η transfer is the heat transfer efficiency.

5. The cryogenic ball valve according to claim 2, characterized in that: The optimal angular velocity of the rotating ring is determined by the following formula: oh optimal =√(2·α·ΔT / (r·ρ·c)) Among them, ω optimal is the optimal angular velocity, α is the thermal diffusion coefficient, ΔT is the allowable temperature difference, r is the radius of the ball valve, ρ is the air density, and c is the specific heat capacity of air.

6. A cryogenic ball valve according to claim 2, characterized in that: The system also includes a temperature feedback control mechanism that dynamically adjusts the heating power according to the following PID control equation: P heat =P base +K p (T target -T actual )+K i ∫(T target -T actual )dt Among them, P heat is the heating power, P base is the basic power, K p is the proportionality coefficient, K i is the integral coefficient, T target is the target temperature, T actual The actual measured temperature.

7. The cryogenic ball valve according to claim 2, characterized in that: The system calculates the steady-state temperature using the following ball valve surface heat balance equation: T surface =T env +(P heat ·η transfer ) / (h·A) Among them, T surface is the surface temperature of the ball valve, T env is the ambient temperature, P heat is the heating power, η transfer is the heat transfer efficiency, h is the comprehensive heat transfer coefficient, and A is the surface area of ​​the ball valve.

8. The cryogenic ball valve according to claim 2, characterized in that: The system also calculates a safety factor against frost: S=((T surface -T frost ) / (T frost -T amb ))·((T max -T surface ) / (T max -T optimal )) Among them, S is the safety factor, T surface is the actual surface temperature, T frost is the frosting temperature, T amb is the ambient temperature, T max is the maximum allowable temperature, T optimal For the best working temperature.

9. A method for preventing frost formation of a cryogenic ball valve based on zone heating, applied to the cryogenic ball valve according to any one of claims 1 to 8, characterized in that: The following steps are involved: Divide the ball valve surface into several heating zones and calculate the heat demand for each zone: Q total =∑(i=1 to n)(m i ·c i ·ΔT i ); Where n is the number of regions, m i The air quality received by each area, c i is the specific heat capacity of air, ΔT i The required temperature rise for each zone; Design the air hole layout of the heating system based on the air flow dynamics equation: A total =n·π·r hole 2 =Q air / n exit ; Among them, A total is the total area of ​​all pores, n is the number of pores, r hole is the pore radius, Q air is the air flow rate, ν exit is the airflow outlet velocity; The heat source rotation is controlled according to the angular velocity equation of the rotating ring: ω ring =(n motor ·Z gear ) / Z ring ; Among them, ω ring is the angular velocity of the rotating ring, n motor is the motor speed, Z gear is the number of teeth of the hollow gear, Z ring is the number of teeth on the gear ring; Calculate the system energy efficiency ratio to evaluate the anti-frost efficiency: η system =(ΔT surface ·A) / (∫[0 to T]P(t)dt); where, η system is the system energy efficiency ratio, ΔT surface is the surface temperature rise, A is the heated surface area, and P(t) is the total power consumption of the system at time t.

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