Anti-freezing anti-crystallization hydraulic breathing valve and control method thereof

Abstract

The application provides a freeze-proof anti-crystallization hydraulic breathing valve and a control method thereof, and belongs to the technical field of breathing valves. The freeze-proof anti-crystallization hydraulic breathing valve comprises a valve body and an upper valve box. A main valve cavity is arranged in the valve body. An inner valve body is arranged in the main valve cavity. A negative pressure valve assembly is arranged in the inner valve body. The negative pressure valve assembly comprises a negative pressure valve seat, a negative pressure diaphragm, a negative pressure valve disc and a negative pressure valve rod. An upper diaphragm is arranged between the valve body and the upper valve box. A valve seat part is arranged at the upper end of the valve body. An anti-freezing liquid is arranged in the upper valve box. The upper diaphragm and the valve seat part form a seal under the gravity of the anti-freezing liquid. In the application, the synergistic effect of the gravity sealing of the anti-freezing liquid and the self-balancing design of the hydraulic pressure solves the technical problems of seal failure in a low-temperature environment, a complex mechanical structure and a dynamic response lag, compared with the conventional breathing valve which relies on elastic elements such as springs to maintain the sealing pressure. The high reliability, long service life and rapid pressure response of the breathing valve are realized, and the application is especially suitable for extreme low-temperature working conditions.

Description

Technical Field

[0001] This invention relates to the field of breather valve technology, specifically to an antifreeze and anti-crystallization hydraulic breather valve and its control method. Background Technology

[0002] A breather valve is a safety protection device used in storage tanks, oil tanks, or sealed containers, primarily for automatically regulating the pressure balance inside and outside the container. Its working principle involves a combination of an internally designed pressure valve and a vacuum valve. When the pressure inside the container is too high (e.g., during liquid expansion due to heat or filling), the pressure valve opens to release gas (exhalation), preventing the container from rupturing. When a negative pressure forms inside the container (e.g., during liquid discharge or cooling contraction), the vacuum valve opens to draw in outside air (inhalation), preventing the container from collapsing. Breather valves are widely used in petroleum, chemical, and warehousing industries, offering explosion-proof, fire-proof, and environmental protection functions (e.g., reducing oil and gas evaporation), making them a key component for ensuring the safe operation of equipment. Traditional hydraulic breather valves rely on elastic elements such as springs to maintain sealing pressure. In low-temperature environments, this often leads to sealing failure due to icing of sealing components or mechanical jamming. The deformation rate of the elastic element does not match the pressure changes inside the tank, resulting in a delayed response under transient high / negative pressure impacts, leading to untimely exhaust or intake. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide an antifreeze and anti-crystallization hydraulic breather valve and its control method.

[0004] The technical solution adopted by the present invention is as follows: In a first aspect, this application provides an antifreeze and anti-crystallization hydraulic breather valve, including a valve body and an upper valve box. The valve body is provided with a main valve chamber, and the main valve chamber is provided with an inner valve body. The inner valve body is provided with an upper cavity, a lower cavity, and a negative pressure valve assembly. The negative pressure valve assembly includes a negative pressure valve seat, a negative pressure diaphragm, a negative pressure valve disc, and a negative pressure valve stem. The negative pressure valve stem slides up and down along the inner valve body. The negative pressure diaphragm abuts against the negative pressure valve disc and the negative pressure valve seat to form a seal. An upper diaphragm is provided between the upper valve box and the valve body. The upper end of the valve body is provided with a valve seat portion. Antifreeze is provided in the upper valve box. An air outlet is provided on the outer ring of the valve seat portion of the valve body. The valve body is provided with an air inlet communicating with the lower cavity and a connection port for communicating with the tank and the main valve chamber. The inner valve body is provided with an opening communicating with the upper cavity and the main valve chamber.

[0005] Under the weight of the antifreeze, the upper diaphragm and the valve seat form a seal;

[0006] When the pressure inside the tank is high, the high-pressure gas pushes the upper diaphragm and valve seat to separate, and the high-pressure gas is discharged from the outlet, thus achieving exhalation.

[0007] When there is negative pressure inside the tank, external gas enters the lower cavity through the air inlet, and pushes the negative pressure diaphragm and negative pressure valve seat to separate. The gas then enters the tank through the valve cavity, thus achieving air intake.

[0008] In some embodiments, a first tube is provided at the lower end of the upper valve box, and a second tube is provided at the upper end of the upper valve box. The first tube and the second tube are arranged parallel to each other, and a third tube is arranged perpendicularly between them. A float is provided in the third tube, and a rod is provided on the float that extends out of the third tube and slides along the axial direction of the third tube. A first trigger switch is provided at the upper end of the third tube, and a first trigger end is provided at the upper end of the rod facing the first trigger switch. When the liquid level in the upper valve box drops, the first trigger end presses down to trigger the first trigger switch.

[0009] In some embodiments, a control box is provided at the upper end of the third tube, a controller is provided inside the control box, the upper end of the rod extends into the control box, the first trigger switch is provided at the bottom inside the control box, a second trigger switch is provided at the upper part inside the control box, and a second trigger end is provided at the upper end of the rod facing the second trigger switch. When the liquid level in the upper valve box rises, the second trigger end triggers the second trigger switch.

[0010] In some embodiments, the system further includes a replenishment tank, a fourth tube is provided at the lower part of the upper valve box, and a fifth tube is provided at the upper part of the upper valve box. A first regulating valve is provided near the upper valve box on the fourth tube, and a second regulating valve is provided near the upper valve box on the fifth tube. The replenishment tank is connected to a pump body, and a control valve is provided between the replenishment tank and the pump body. A reversing valve is provided between the pump body and the fourth and fifth tubes.

[0011] In some embodiments, a cover is provided on the top of the upper valve box, an extension rod is provided on the upper side of the upper diaphragm, the upper end of the extension rod passes through the upper valve box and extends into the cover, a first displacement sensor is provided on the top of the cover corresponding to the extension rod, and a second displacement sensor is provided inside the control box corresponding to the rod.

[0012] In some embodiments, a sealing cavity is provided at the top of the upper valve box, through which the extension rod passes. The sealing cavity includes an upper chamber and a lower chamber. An adsorption block is provided in the lower chamber, and an upper double-lip oil seal, graphite packing, and a lower double-lip oil seal are provided in the upper chamber.

[0013] In some embodiments, the upper end of the negative pressure valve stem extends out of the inner valve body and is provided with a top plate. When the negative pressure valve stem rises to a height exceeding a threshold due to the negative pressure inside the tank, the top plate lifts the upper diaphragm to separate it from the valve seat, and the vent hole draws in air.

[0014] Secondly, this application also provides a control method for the aforementioned antifreeze and anti-crystallization hydraulic breather valve, comprising the following steps:

[0015] Step S1: Under normal pressure inside the tank, antifreeze of the target level is introduced into the upper valve box. The initial position of the extension rod is obtained through the first displacement sensor and the initial position of the rod is obtained through the second displacement sensor.

[0016] Step S2: The axial displacement of the extension rod is acquired in real time using the first displacement sensor, and the axial displacement of the rod is acquired in real time using the second displacement sensor.

[0017] Step S3: Determine whether the axial displacement of the extension rod is less than the displacement judgment threshold.

[0018] If the level is less than the displacement threshold, the current level of the antifreeze is obtained based on the axial displacement of the rod.

[0019] If the displacement is greater than the displacement threshold, the actual liquid level is calculated based on the axial displacement of the rod and the axial displacement of the extension rod.

[0020] Step S4: Based on the comparison results between the current liquid level and the target liquid level or the comparison results between the actual liquid level and the target liquid level, if the comparison results exceed the error range of the target liquid level, then start the liquid replenishment program or the liquid drainage program.

[0021] In some embodiments, in step S3, the liquid level correction caused by the displacement of the upper diaphragm is calculated, and the actual liquid level is calculated based on the axial displacement of the rod and the liquid level correction, wherein the liquid level correction is the ratio of the product of the axial displacement of the extension rod and the effective cross-sectional area of ​​the upper diaphragm to the effective cross-sectional area of ​​the upper valve box.

[0022] In some embodiments, before the triggering operation in step S4, a second-order filtering process is performed on the actual liquid level and the current liquid level. If the deviation between the filtered liquid level value and the previous valid value exceeds the warning value, it is marked as invalid data. The invalid data is replaced with the linear extrapolation value of the most recent valid filtered value and the previous data. The liquid replenishment program or the liquid drainage program is started based on the corrected liquid level value.

[0023] The beneficial effects of the present invention are as follows: The present invention solves the technical problems of sealing failure, complex mechanical structure and dynamic response lag in low temperature environment by means of the synergistic effect of antifreeze gravity sealing and hydraulic self-balancing design, compared with the traditional breather valve which relies on elastic elements such as springs to maintain sealing pressure. This achieves high reliability, long service life and fast pressure response of the breather valve, and is suitable for extreme low temperature working conditions. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0025] Figure 1 This is a schematic diagram of the antifreeze and anti-crystallization hydraulic breather valve of the present invention;

[0026] Figure 2 This is a schematic diagram of the negative pressure valve assembly in this invention;

[0027] Figure 3 This is a schematic diagram of another antifreeze and anti-crystallization hydraulic breather valve in this invention;

[0028] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0029] Figure 5 for Figure 3 Enlarged view of point B in the middle;

[0030] Figure 6 This is a schematic diagram of the sealing cavity in this invention;

[0031] Figure 7 This is a flowchart of the control method for the antifreeze and anti-crystallization hydraulic breather valve in this invention. Detailed Implementation

[0032] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "longitudinal", "lateral", "radial", "length", "width", "thickness", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element or component to have a specific orientation, or to be constructed and operated in a specific orientation.

[0034] It should be noted that the terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are only used to distinguish different components and should not be construed as limiting the embodiments of this application.

[0035] It should be noted that the terms "installation," "setup," "equipped with," "connection," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral structures; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or internal connections between two devices, components, or parts.

[0036] It should be noted that the terms "in some embodiments," "exemplarily," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "in some embodiments," "exemplarily," or "for example" should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "in some embodiments," "exemplarily," and "for example" is intended to present related concepts in a specific manner, meaning that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the above terms in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0037] Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0038] Regarding the accompanying drawings of this application, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not necessarily drawn to scale.

[0039] like Figures 1 to 6As shown in the figure, this specification provides an antifreeze and anti-crystallization hydraulic breather valve, including a valve body 1 and an upper valve box 2. The valve body 1 has a main valve chamber 100, and the main valve chamber 100 has an inner valve body 3. The inner valve body 3 has an upper chamber 30, a lower chamber 31, and a negative pressure valve assembly 4. The negative pressure valve assembly 4 includes a negative pressure valve seat 40, a negative pressure diaphragm 41, a negative pressure valve disc 42, and a negative pressure valve stem 43. The negative pressure valve stem 43 slides up and down along the inner valve body 3. A pressure diaphragm 41 abuts against the negative pressure valve disc 42 and the negative pressure valve seat 40 to form a seal. An upper diaphragm 5 is provided between the upper valve box 2 and the valve body 1. A valve seat portion 101 is provided at the upper end of the valve body 1. Antifreeze 6 is provided inside the upper valve box 2. An air outlet 7 is provided on the valve body 1 at the outer ring of the valve seat portion 101. Generally, multiple outlets are evenly arranged circumferentially. A diaphragm-type antifreeze and anti-crystallization breather valve disclosed in patent publication number CN217762234U can be referenced.

[0040] The valve body 1 is provided with an air inlet 102 communicating with the lower cavity 31 and a connection port 103 for communicating with the tank and the main valve chamber 100. The inner valve body 3 is provided with an opening 32 communicating with the upper cavity 30 and the main valve chamber 100. Under the gravity of the antifreeze 6, the upper diaphragm 5 and the valve seat 101 form a seal. When the tank is under high pressure, the high pressure gas pushes the upper diaphragm 5 and the valve seat 101 to separate, and the high pressure gas is discharged from the air outlet 7 to achieve exhalation. When the tank is under negative pressure, the external gas enters the lower cavity 31 through the air inlet 102 and pushes the negative pressure diaphragm 41 and the negative pressure valve seat 40 to separate, and enters the tank through the main valve chamber 100 to achieve inhalation.

[0041] This configuration utilizes the gravity of the antifreeze 6 to form a seal between the upper diaphragm 5 and the valve seat 101, eliminating the need for spring preload. The low-temperature fluidity of the antifreeze 6 (e.g., an ethylene glycol-based solution remains liquid at -40°C) avoids the risk of crystallization, ensuring that the upper diaphragm 5 is always subjected to constant gravity, maintaining stable sealing pressure. At the same time, it eliminates the sealing pressure attenuation problem caused by the brittleness or fatigue of traditional springs at low temperatures.

[0042] Compared to traditional springs or mechanical structures, hydraulic seals are more reliable, especially in low-temperature environments, as they prevent antifreeze from crystallizing, maintaining fluidity and ensuring a tight seal. They also eliminate complex mechanical parts, simplifying the structure and reducing maintenance costs. Furthermore, hydraulic seals respond more sensitively to pressure changes, improving the response speed of the breather valve, making them particularly suitable for extreme low-temperature conditions.

[0043] In some embodiments, the lower end of the upper valve box 2 is provided with a first tube 80, and the upper end of the upper valve box 2 is provided with a second tube 81. The first tube 80 and the second tube 81 are arranged parallel to each other, and a third tube 82 is arranged perpendicularly between them. A float 83 is provided inside the third tube 82. Under normal circumstances, the liquid level in the third tube 82 is the same as the liquid level in the upper valve box 2. A rod 84 is provided on the float 83, which extends out of the third tube 82 and slides along the axial direction of the third tube 82. A first trigger switch 85 is provided at the upper end of the third tube 82. The upper end of the rod 84 is provided with a first trigger end 841 facing the first trigger switch 85. With this configuration, when the liquid level in the upper valve box 2 drops, the first trigger end 841 presses down to trigger the first trigger switch 85, which can issue a warning to remind the user to replenish antifreeze in time.

[0044] Furthermore, a control box 86 is provided at the upper end of the third tube 82, and a controller is provided inside the control box 86. The upper end of the rod 84 extends into the control box 86. The first trigger switch 85 is located at the bottom inside the control box 86. A second trigger switch 87 is provided at the upper part inside the control box 86. A second trigger end 842 is provided at the upper end of the rod 84 facing the second trigger switch 87. Generally, when adding antifreeze to the upper valve box 2, if too much is added, causing the liquid level in the upper valve box 2 to rise too high, the second trigger end 842 will trigger the second trigger switch 87, which can also issue a corresponding warning to remind the user to drain the liquid in time.

[0045] However, it should be noted that within the normal high pressure range, if the upper diaphragm 5 is pushed up, causing the liquid level to rise, it will not trigger the second trigger switch 87.

[0046] Preferably, the third tube 82 is transparent and is equipped with a standard liquid level, so that the antifreeze level can be observed in a timely manner to see if it meets the requirements.

[0047] In this hydraulic breather valve, it is important to control the gravity of the antifreeze 6 to ensure that the upper diaphragm 5 and the valve seat 101 form a seal under normal pressure, while being able to separate and release air under high pressure.

[0048] Based on this, in some embodiments, a replenishment tank 9 is also included. A fourth tube 90 is provided at the lower part of the upper valve box 2, and a fifth tube 91 is provided at the upper part. A first regulating valve 92 is provided near the upper valve box 2 on the fourth tube 90, and a second regulating valve 93 is provided near the upper valve box 2 on the fifth tube 91. The replenishment tank 9 is connected to a pump body 94, and a control valve 95 is provided between the pump body 94 and the fourth tube 90 and the fifth tube 91. A reversing valve 96 is provided. When liquid replenishment is required, the reversing valve 96 connects the pump body 94 and the fourth pipe 90, the control valve 95 opens, the pump body 94 starts, and a certain amount of antifreeze 6 flows into the upper valve box 2 through the first regulating valve 92. When liquid drainage is required, the reversing valve 96 connects the pump body 94 and the fifth pipe 91, the control valve 95 opens, the pump body 94 starts, and a certain amount of antifreeze 6 flows out of the upper valve box 2 through the second regulating valve 93.

[0049] Among them, the first regulating valve 92 and the second regulating valve 93 are valves that at least meet the requirements of flow regulation, such as solenoid valves; the control valve 95 is a valve that at least meets the requirements of fluid on / off, such as ball valves and shut-off valves; and the reversing valve 96 is a valve that has at least two switching options, such as a three-way ball valve, and preferably also has two valves that can open and close simultaneously, such as a multi-position multi-way reversing valve. In this way, when the equipment is not used for a long time, the antifreeze 6 in each pipe can be recovered to the replenishment tank 9 for storage.

[0050] Furthermore, a cover 10 is provided on the top of the upper valve box 2, and an extension rod 50 is provided on the upper side of the upper diaphragm 5. The extension rod 50 is preferably a thin rod that is corrosion resistant and has a smooth surface. The upper end of the extension rod 50 passes through the upper valve box 2 and extends into the cover 10. A first displacement sensor 11 is provided on the top of the cover 10 corresponding to the extension rod 50, and a second displacement sensor 12 is provided in the control box 86 corresponding to the rod portion 84.

[0051] With this configuration, the movement of the upper diaphragm 5 is prevented from affecting the antifreeze level by using the first displacement sensor 11 and the second displacement sensor 12, along with the corresponding control method, ensuring that the gravity of the antifreeze meets the requirements.

[0052] In some embodiments, a sealing cavity 13 is provided at the top of the upper valve box 2, through which the extension rod 50 passes. The sealing cavity 13 includes an upper chamber 130 and a lower chamber 131. An adsorption block 132, such as polyurethane open-cell foam, is provided in the lower chamber 131. An upper double-lip oil seal 133, a graphite filler 134, and a lower double-lip oil seal 135 are provided in the upper chamber 130. This arrangement prevents antifreeze leakage.

[0053] It is understandable that this sealed cavity structure is also provided between the rod 84 and the control box 86 to prevent antifreeze leakage.

[0054] In some embodiments, the upper end of the negative pressure valve stem 43 extends out of the inner valve body 3 and is provided with a top plate 14. When the negative pressure valve stem 43 rises to a height exceeding a threshold due to the negative pressure inside the tank, the top plate 14 lifts up the upper diaphragm 5 to separate it from the valve seat 101, and the vent 7 draws in air, thereby increasing the upper pressure resistance limit of the breather valve.

[0055] like Figure 7 As shown, the control method applied to the aforementioned antifreeze and anti-crystallization hydraulic breather valve includes the following steps:

[0056] Step S1: Under normal pressure inside the tank, antifreeze 6 at the target level is input into the upper valve box 2. The initial position of the extension rod 50 is obtained through the first displacement sensor 11, and the initial position of the rod 84 is obtained through the second displacement sensor 12.

[0057] Step S2: The axial displacement of the extension rod 50 is acquired in real time by the first displacement sensor 11. The axial displacement of the rod 84 is acquired in real time by the second displacement sensor 12. ;

[0058] Step S3: Determine whether the axial displacement of the extension rod 50 is less than the displacement judgment threshold. This threshold is generally set between 0.3mm and 0.5mm, preferably 0.5mm.

[0059] If it is less than the displacement judgment threshold, the current level of antifreeze 6 is obtained based on the axial displacement of rod 84;

[0060] If the displacement is greater than the displacement threshold, the actual liquid level is calculated based on the axial displacement of rod 84 and the axial displacement of extension rod 50.

[0061] In most operating conditions (such as steady-state pressure), only a single sensor data is required, which reduces the processor load and shortens the response cycle. Secondly, small displacements, such as micro-vibrations of the upper diaphragm caused by temperature fluctuations, do not trigger corrections, preventing control oscillations caused by frequent fluctuations in liquid level.

[0062] Specifically, when calculating the actual liquid level, the liquid level correction caused by the displacement of diaphragm 5 is calculated. The actual liquid level is calculated based on the axial displacement of the rod 84 and the liquid level correction, wherein the liquid level correction is the sum of the axial displacement of the extension rod 50 and the effective cross-sectional area of ​​the upper diaphragm 5. The product of the product and the effective cross-sectional area of ​​the upper valve box 2 The ratio of .

[0063] Among them, liquid level correction amount The calculation formula is:

[0064] ;

[0065] Compared to the axial displacement of directly using extension rod 50 This serves as a correction measure, thus preventing overestimation of liquid level fluctuations.

[0066] Step S4: Based on the comparison results between the current liquid level and the target liquid level or the comparison results between the actual liquid level and the target liquid level, if the comparison result exceeds the error range of the target liquid level, which is generally 1mm-3mm, then start the liquid replenishment program or the liquid draining program.

[0067] The replenishment procedure is as follows: the reversing valve 96 connects the pump body 94 and the fourth pipe body 90, the control valve 95 is opened, the pump body 94 is started, and a certain amount of antifreeze 6 flows into the upper valve box 2 through the first regulating valve 92.

[0068] The drainage procedure is as follows: the reversing valve 96 connects the pump body 94 and the fifth pipe body 91, the control valve 95 is opened, the pump body 94 is started, and a certain amount of antifreeze 6 flows out of the upper valve box 2 through the second regulating valve 93.

[0069] Before the operation is triggered in step S4, the actual liquid level and the current liquid level are subjected to second-order filtering. If the deviation between the filtered liquid level value and the previous valid value exceeds the warning value, which is generally 1mm-3mm, it is marked as invalid data. The invalid data is replaced with the linear extrapolation value of the most recent valid filtered value and the previous data. The liquid replenishment program or the liquid drainage program is started based on the corrected liquid level value.

[0070] In this way, when the filtered liquid level deviation exceeds the warning value, the abnormal data is replaced by a linear extrapolation value to avoid transient interference triggering erroneous operations.

[0071] The second-order filtering process includes the following steps:

[0072] Cache consecutive items in chronological order. Group liquid level value ,in The sampling interval for each group of data is ;

[0073] Second-order difference filter calculation:

[0074] For each liquid level value Calculate its second derivative estimate:

[0075] ;

[0076] The original liquid level value is corrected using a low-pass filter formula:

[0077] ;

[0078] in, These are the filter coefficients, and their values ​​range from [value range missing]. The low-pass filter coefficient balances response speed and stability, avoiding control misjudgment due to single sampling anomalies.

[0079] It also includes fault protection mechanisms:

[0080] When the axial displacement fluctuation frequency and change rate of rod 84 are lower than the preset threshold, it is determined that the float 83 rod 84 is stuck or the first sensor is faulty, and the liquid level estimation mode is switched.

[0081] For example:

[0082] and ;

[0083] When the float 83 rod 84 is working normally, it will generate displacement at a certain frequency with the fluctuation of the liquid level. If the float 83 rod 84 is stuck, the spectral energy of its displacement signal will be concentrated in the extremely low frequency band. The float 83 rod 84 should have a significant speed under normal liquid level changes. In the stuck state, the displacement of the float 83 rod 84 is almost stagnant and the speed approaches zero. The dual criteria (frequency domain + time domain) can distinguish between real stuckness and brief stagnation, greatly reducing the false alarm rate.

[0084] The liquid level estimation mode calculates the emergency liquid level value based on the axial displacement of the extension rod 50. The calculation formula is as follows:

[0085] ;

[0086] Based on the emergency liquid level value, the antifreeze 6 will initiate either a replenishment or drainage procedure.

[0087] In this way, the emergency liquid level value uses the same area ratio parameter as the normal mode to ensure seamless data connection between the main and backup modes. At the same time, when replacing abnormal data, linear trend prediction based on historical effective values ​​is used to avoid control instability caused by algorithm mutation. The main and backup modes share the same physical model to reduce liquid level jumps when switching modes.

[0088] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that the requirements of this application encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this application and are within the spirit and scope of the exemplary embodiments of this application.

[0089] Furthermore, it should be understood that in the foregoing description of the embodiments of this application, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may readily identify some of the devices as separate embodiments when reading this application. That is, the embodiments in this application can also be understood as an integration of multiple sub-embodiments. It is also valid when each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0090] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments of this application. Other modified embodiments are also within the scope of this application. Therefore, the embodiments disclosed herein are merely examples and not limitations. Those skilled in the art can adopt alternative configurations to implement the applications in this application based on the embodiments in this application. Therefore, the embodiments of this application are not limited to the embodiments precisely described in the application.

Claims

1. A control method for an antifreeze and anti-crystallization hydraulic breather valve, characterized in that, The breathing valve includes a valve body and an upper valve box. A main valve chamber is located within the valve body, and an inner valve body is located within the main valve chamber. The inner valve body contains an upper chamber, a lower chamber, and a negative pressure valve assembly. The negative pressure valve assembly includes a negative pressure valve seat, a negative pressure diaphragm, a negative pressure valve disc, and a negative pressure valve stem. The negative pressure valve stem slides up and down along the inner valve body. The negative pressure diaphragm abuts against the negative pressure valve disc and the negative pressure valve seat to form a seal. An upper diaphragm is located between the upper valve box and the valve body. A valve seat is located at the upper end of the valve body. Antifreeze is contained within the upper valve box. An air outlet is located on the outer ring of the valve seat on the valve body. An air inlet communicating with the lower chamber and a connection to the tank are also provided on the valve body. The inner valve body has an opening connecting the upper cavity and the main valve chamber, which is connected to the main valve chamber. Under the gravity of the antifreeze, the upper diaphragm and the valve seat form a seal. When the tank is under high pressure, the high-pressure gas pushes the upper diaphragm and the valve seat to separate, and the high-pressure gas is discharged from the vent, achieving exhalation. When the tank is under negative pressure, external gas enters the lower cavity through the inlet and pushes the negative pressure diaphragm and the negative pressure valve seat to separate, and enters the tank through the valve chamber, achieving inhalation. The lower end of the upper valve box is provided with a first tube, and the upper end is provided with a second tube. The first and second tubes are arranged parallel to each other, and a third tube is arranged perpendicularly between them. A float is provided in the third tube. A rod is provided on the float, extending through a third tube and sliding axially along the third tube. A first trigger switch is provided at the upper end of the third tube, and a first trigger end is provided at the upper end of the rod facing the first trigger switch. When the liquid level in the upper valve box drops, the first trigger end presses down to trigger the first trigger switch. A control box is provided at the upper end of the third tube, and a controller is provided inside the control box. The upper end of the rod extends into the control box, and the first trigger switch is located at the bottom of the control box. A second trigger switch is provided at the upper part of the control box, and a second trigger end is provided at the upper end of the rod facing the second trigger switch. When the liquid level in the upper valve box rises, the second trigger end... The upper valve box is equipped with a second trigger switch and a replenishment tank. A fourth tube is located at the lower part of the upper valve box, and a fifth tube is located at the upper part. A first regulating valve is located near the upper valve box on the fourth tube, and a second regulating valve is located near the upper valve box on the fifth tube. The replenishment tank is connected to a pump body, and a control valve is located between the tank and the pump body. A reversing valve is located between the pump body and the fourth and fifth tubes. A cover is located at the top of the upper valve box. An extension rod is located on the upper side of the upper diaphragm. The upper end of the extension rod passes through the upper valve box and extends into the cover. A first displacement sensor is located at the top of the cover corresponding to the extension rod, and a second displacement sensor is located inside the control box corresponding to the rod. The control method includes the following steps: Step S1: Under normal pressure in the tank, antifreeze of the target level is input into the upper valve box. The initial position of the extension rod is obtained through the first displacement sensor, and the initial position of the rod is obtained through the second displacement sensor; Step S2: The axial displacement of the extension rod is obtained in real time through the first displacement sensor, and the axial displacement of the rod is obtained in real time through the second displacement sensor; Step S3: It is determined whether the axial displacement of the extension rod is less than the displacement judgment threshold. If it is less than the displacement judgment threshold, the current level of antifreeze is obtained based on the axial displacement of the rod; if it is greater than the displacement judgment threshold, the actual level is calculated based on the axial displacement of the rod and the axial displacement of the extension rod; Step S4: Based on the comparison result between the current level and the target level or the comparison result between the actual level and the target level, if the comparison result exceeds the error range of the target level, the replenishment program or the drainage program is started.

2. The control method for the antifreeze and anti-crystallization hydraulic breather valve according to claim 1, characterized in that, The top of the upper valve box is provided with a sealing cavity, through which the extension rod passes. The sealing cavity includes an upper chamber and a lower chamber. An adsorption block is provided in the lower chamber, and an upper double-lip oil seal, graphite packing, and a lower double-lip oil seal are provided in the upper chamber.

3. The control method for the antifreeze and anti-crystallization hydraulic breather valve according to claim 1, characterized in that, The upper end of the negative pressure valve stem extends out of the inner valve body and is provided with a top plate. When the negative pressure valve stem rises to a height exceeding the threshold due to the negative pressure inside the tank, the top plate lifts the upper diaphragm to separate it from the valve seat, and the vent hole draws in air.

4. The control method for the antifreeze and anti-crystallization hydraulic breather valve according to claim 1, characterized in that, In step S3, the liquid level correction caused by the displacement of the upper diaphragm is calculated, and the actual liquid level is calculated based on the axial displacement of the rod and the liquid level correction. The liquid level correction is the ratio of the product of the axial displacement of the extension rod and the effective cross-sectional area of ​​the upper diaphragm to the effective cross-sectional area of ​​the upper valve box.

5. The control method for the antifreeze and anti-crystallization hydraulic breather valve according to claim 1, characterized in that, Before the operation is triggered in step S4, the actual liquid level and the current liquid level are subjected to second-order filtering. If the deviation between the filtered liquid level value and the previous valid value exceeds the warning value, it is marked as invalid data. The invalid data is replaced with the linear extrapolation value of the most recent valid filtered value and the previous data. The liquid replenishment program or the liquid drainage program is started based on the corrected liquid level value.

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