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

Abstract

The invention provides an anti-freezing and anti-crystallization hydraulic breather valve and a control method thereof, and belongs to the technical field of breather valves, the anti-freezing and anti-crystallization hydraulic breather valve comprises a valve body and an upper valve box, the valve body is internally provided with a main valve cavity, the main valve cavity is internally provided with an inner valve body, the inner valve body is internally provided with a negative pressure valve assembly, and 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 upper valve box and the valve body, a valve seat part is arranged at the upper end of the valve body, an anti-freezing solution is arranged in the upper valve box, and the upper diaphragm and the valve seat part are sealed under the gravity of the anti-freezing solution; through the synergistic effect of anti-freezing solution gravity sealing and hydraulic self-balancing design, compared with a traditional breather valve which depends on elastic elements such as a spring to maintain sealing pressure, the technical problems of sealing failure, complex mechanical structure, dynamic response lag and the like in a low-temperature environment are solved; high reliability, long service life and rapid pressure response of the breather valve are achieved, and the breather valve is particularly suitable for the extremely low-temperature working condition.

Description

Technical Field

[0001] The present invention relates to the technical field of breathing valves, and in particular to an antifreeze and anti-crystallization hydraulic breathing valve and a control method thereof. Background Art

[0002] A breather valve is a safety device used in storage tanks, oil tanks, or sealed containers. It automatically balances the pressure inside and outside the container. Its operating principle is a combination of an internally designed pressure valve and a vacuum valve. When the pressure inside the container is excessively high (such as when the liquid expands due to heat or during filling), the pressure valve opens to release gas (exhalation), preventing the container from rupturing. When negative pressure forms inside the container (such as when the liquid is drained or contracts due to cooling), the vacuum valve opens to let in outside air (inhalation), preventing the container from collapsing. Breather valves are widely used in the petroleum, chemical, and warehousing industries. They combine explosion-proof and fire-proof features with environmental protection (such as reducing oil and gas volatilization), making them a critical 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, seal failure often occurs due to icing of the sealing components or mechanical seizure. The deformation rate of the elastic element does not match the pressure change inside the tank, resulting in a delayed response to transient high / negative pressure shocks, resulting in untimely exhaust or intake. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide an antifreeze and anti-crystallization hydraulic breathing valve and a control method thereof.

[0004] When the valve body is opened, the valve body is closed and the valve is in a closed state, and the upper and lower ends of the valve body are closed, and the upper and lower ends of the valve body are closed. Under the gravity of the antifreeze liquid, the upper diaphragm and the valve seat form a seal; When the pressure inside the tank is high, the high-pressure gas pushes the upper diaphragm and the valve seat apart, and the high-pressure gas is discharged from the air outlet to achieve exhalation; When the tank is under negative pressure, the external gas enters the lower cavity through the air inlet, lifts up the negative pressure diaphragm and separates the negative pressure valve seat, and enters the tank through the valve cavity to achieve air inhalation.

[0005] In some embodiments, a first tube body is provided at the lower end of the upper valve box, and a second tube body is provided at the upper end thereof. The first tube body and the second tube body are arranged in parallel, and a third tube body is arranged vertically therebetween. A float is provided in the third tube body, and a rod is provided on the float to pass through the third tube body and slide axially along the third tube body. A first trigger switch is provided at the upper end of the third tube body, 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.

[0006] In some embodiments, a control box is provided at the upper end of the third tube body, a controller is provided in the control box, the upper end of the rod extends into the control box, the first trigger switch is provided 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 pushes up to trigger the second trigger switch.

[0007] In some embodiments, a fluid replenishing tank is further included, wherein a fourth tube body is provided at the lower portion of the upper valve box, and a fifth tube body is provided at the upper portion thereof, the fourth tube body is provided with a first regulating valve close to the upper valve box, and the fifth tube body is provided with a second regulating valve close to the upper valve box, the fluid replenishing tank is connected to a pump body, and a control valve is provided between the fluid replenishing tank and the pump body, and a reversing valve is provided between the pump body and the fourth tube body and the fifth tube body.

[0008] 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 on the corresponding rod part in the control box.

[0009] In some embodiments, a sealing cavity is provided on the top of the upper valve box, the extension rod passes through the sealing cavity, 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, a graphite filler and a lower double-lip oil seal are provided in the upper chamber.

[0010] 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 is lifted to a height exceeding a threshold due to the negative pressure in the tank body, the top plate lifts the upper diaphragm to separate it from the valve seat, and the air outlet is used to inhale air.

[0011] In a second aspect, the present application further provides a control method for the antifreeze and anti-crystallization hydraulic breathing valve, comprising the following steps: Step S1: When the tank is under normal pressure, the antifreeze liquid at a target liquid level is input into the upper valve box, the initial position of the extension rod is obtained by the first displacement sensor, and the initial position of the rod portion is obtained by the second displacement sensor; Step S2: obtaining the axial displacement of the extension rod in real time through the first displacement sensor, and obtaining the axial displacement of the rod portion in real time through the second displacement sensor; Step S3: Determine whether the axial displacement of the extension rod is less than a displacement determination threshold: If it is less than the displacement determination threshold, the current liquid level of the antifreeze fluid is obtained based on the axial displacement of the rod; If it is greater than the displacement judgment threshold, the actual liquid 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 liquid level and the target liquid level or the comparison result between the actual liquid level and the target liquid level, if the comparison result exceeds the error range of the target liquid level, the liquid replenishment program or the liquid discharge program is started.

[0012] 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 product of the axial displacement of the extension rod and the effective cross-sectional area of ​​the upper diaphragm and the ratio of the effective cross-sectional area of ​​the upper valve box.

[0013] In some embodiments, before the step S4 triggering operation, 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, and the invalid data is replaced by the linear extrapolation value of the most recent valid filtered value and the previous data, and the refilling program or the drainage program is started based on the corrected liquid level value.

[0014] The beneficial effects of the present invention are as follows: In the present invention, through the synergistic effect of the antifreeze gravity seal and the hydraulic self-balancing design, compared with the traditional breathing valve that relies on elastic elements such as springs to maintain sealing pressure, it solves the technical problems such as sealing failure in low temperature environment, complex mechanical structure and dynamic response lag, and realizes the high reliability, long service life and rapid pressure response of the breathing valve, which is suitable for extreme low temperature working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0016] Figure 1Schematic diagram of the antifreeze and anti-crystallization hydraulic breathing valve of the present invention; Figure 2 Schematic diagram of the negative pressure valve assembly of the present invention; Figure 3 Schematic diagram of another antifreeze and anti-crystallization hydraulic breathing valve in the present invention; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 for Figure 3 Enlarged view of point B in the middle; Figure 6 Schematic diagram of the sealed cavity in the present invention; Figure 7 The figure is a flow chart of the control method of the antifreeze and anti-crystallization hydraulic breathing valve in the present invention. DETAILED DESCRIPTION

[0017] The following description provides specific application scenarios and requirements for this specification, with the goal of enabling those skilled in the art to make and use the contents of this specification. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may 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 is intended to be accorded the broadest scope consistent with the claims.

[0018] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "longitudinal", "transverse", "radial", "length", "width", "thickness", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe this application and its embodiments, and are not intended to limit the indicated devices, elements or components to a specific orientation, or to be constructed and operated in a specific orientation.

[0019] 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 understood as limitations on the embodiments of the present application.

[0020] It should be noted that the terms "installed," "set," "provided with," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; or internal communication between two devices, elements, or components.

[0021] It should be noted that the terms "in some embodiments", "exemplarily", "for example", etc. are used to indicate examples, illustrations or descriptions. Any embodiment or design described in this application as "in some embodiments", "exemplarily", "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "in some embodiments", "exemplarily", "for example" is intended to present related concepts in a concrete way, meaning that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the above words in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] Regarding the drawings of this application, it should be clearly understood that the drawings are for illustration and description 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.

[0024] like Figures 1 to 6 As shown, this specification provides an antifreeze and anti-crystallization hydraulic breathing valve, including a valve body 1 and an upper valve box 2, a main valve cavity 100 is provided in the valve body 1, an inner valve body 3 is provided in the main valve cavity 100, an upper cavity 30, a lower cavity 31 and a negative pressure valve assembly 4 are provided in the inner valve body 3, and 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 is arranged to slide up and down along the inner valve body 3, and the negative pressure valve stem 43 is arranged to slide up and down along the inner valve body 3. The 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 arranged 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 liquid 6 is provided in the upper valve box 2. An air outlet 7 is provided on the outer ring of the valve seat portion 101 on the valve body 1. Generally, multiple air outlets 7 are evenly arranged along the circumference. You can refer to the diaphragm antifreeze and anti-crystallization breathing valve disclosed in the patent with publication number CN217762234U.

[0025] The valve body 1 is provided with an air inlet hole 102 connected to the lower cavity 31 and a connecting port 103 for connecting the tank body and the main valve cavity 100. The inner valve body 3 is provided with an opening 32 connecting the upper cavity 30 and the main valve cavity 100. Under the gravity of the antifreeze liquid 6, the upper diaphragm 5 and the valve seat 101 form a seal. When the tank body 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 body is under negative pressure, the external gas enters the lower cavity 31 through the air inlet hole 102, and lifts the negative pressure diaphragm 41 and the negative pressure valve seat 40 to separate, and enters the tank body through the main valve cavity 100 to achieve inhalation.

[0026] With this arrangement, the gravity of the antifreeze liquid 6 is used to form a seal between the upper diaphragm 5 and the valve seat portion 101, without relying on the spring preload. The low-temperature fluidity of the antifreeze liquid 6 (for example, ethylene glycol-based solutions remain liquid at -40°C) avoids the risk of crystallization, ensuring that the upper diaphragm 5 is always subjected to constant gravity, maintaining a stable sealing pressure, and eliminating the problem of sealing pressure attenuation caused by the brittleness or fatigue of low-temperature materials in traditional springs.

[0027] This design is more reliable than traditional springs or mechanical structures, especially in low-temperature environments. Antifreeze is less likely to crystallize, maintaining fluidity and ensuring a tight seal. It also eliminates complex mechanical components, resulting in a simplified structure and lower maintenance costs. Furthermore, the hydraulic seal is more responsive to pressure changes, improving the response speed of the breathing valve, making it particularly suitable for use in extremely low-temperature conditions.

[0028] In some embodiments, a first tube body 80 is provided at the lower end of the upper valve box 2, and a second tube body 81 is provided at the upper end thereof. The first tube body 80 and the second tube body 81 are arranged in parallel, and a third tube body 82 is vertically arranged therebetween. A float 83 is provided in the third tube body 82. Under normal circumstances, the liquid level in the third tube body 82 is the same as the liquid level in the upper valve box 2. A rod 84 is provided on the float 83 to pass through the third tube body 82 and is axially slidable along the third tube body 82. A first trigger switch 85 is provided at the upper end of the third tube body 82, and a first trigger end 841 is provided at the upper end of the rod 84 facing the first trigger switch 85. With such an arrangement, 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. At this time, a corresponding alarm can be issued to remind the user to replenish antifreeze in time.

[0029] Furthermore, a control box 86 is provided at the upper end of the third tube body 82, and a controller is provided in the control box 86. The upper end of the rod 84 extends into the control box 86, and the first trigger switch 85 is provided at the bottom of the control box 86. A second trigger switch 87 is provided in the upper part of the control box 86. The upper end of the rod 84 is provided with a second trigger end 842 facing the second trigger switch 87. Generally, when the antifreeze liquid is replenished to the upper valve box 2, if the replenishment is excessive, causing the liquid level in the upper valve box 2 to rise too high, the second trigger end 842 pushes up to trigger the second trigger switch 87, and can also issue a corresponding warning to remind the user to drain the liquid in time.

[0030] However, it should be noted that within the normal high pressure range, the second trigger switch 87 will not be triggered when the upper diaphragm 5 is pushed up to increase the liquid level.

[0031] Preferably, the third tube 82 is transparent and is provided with a standard liquid level, so that it is possible to timely observe whether the antifreeze liquid level meets the requirements.

[0032] The most important thing in this hydraulic breathing valve is to control the gravity of the antifreeze liquid 6 to ensure that the upper diaphragm 5 and the valve seat 101 form a seal under normal pressure, and can separate and exhaust under high pressure.

[0033] Based on this, in some embodiments, a liquid replenishing tank 9 is further included, a fourth tube body 90 is provided at the lower part of the upper valve box 2, a fifth tube body 91 is provided at the upper part thereof, the fourth tube body 90 is provided with a first regulating valve 92 close to the upper valve box 2, the fifth tube body 91 is provided with a second regulating valve 93 close to the upper valve box 2, the liquid replenishing 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 body 90 and the fifth tube body 91. A reversing valve 96 is provided. When fluid replenishment is required, 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 fixed amount of antifreeze liquid 6 flows into the upper valve box 2 through the first regulating valve 92; when fluid discharge is required, 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 fixed amount of antifreeze liquid 6 flows out of the upper valve box 2 through the second regulating valve 93.

[0034] Among them, the first regulating valve 92 and the second regulating valve 93 adopt valves that at least meet the flow regulation requirements, such as solenoid valves, the control valve 95 adopts a valve that at least meets the fluid on-off requirements, such as a ball valve and a stop valve, and the reversing valve 96 adopts a valve with at least two-way switching, such as a three-way ball valve, and preferably also has a valve that can open and disconnect two ways at the same time, such as a multi-position multi-way reversing valve. In this way, when the equipment is not used for a long time, the antifreeze fluid 6 in each pipe body can be recovered to the fluid replenishment tank 9 for storage.

[0035] Furthermore, a cover body 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 body 10. A first displacement sensor 11 is provided at the top of the cover body 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.

[0036] With such arrangement, the first displacement sensor 11 and the second displacement sensor 12 are coordinated with the corresponding control method to avoid the influence of the movement of the upper diaphragm 5 on the antifreeze liquid level, thereby ensuring that the gravity of the antifreeze liquid meets the requirements.

[0037] In some embodiments, a sealed cavity 13 is provided on the top of the upper valve box 2, and the extension rod 50 passes through the sealed cavity 13. The sealed cavity 13 includes an upper chamber 130 and a lower chamber 131. An adsorption block 132 is provided in the lower chamber 131, such as polyurethane open-cell foam. The upper chamber 130 contains an upper double-lip oil seal 133, a graphite filler 134 and a lower double-lip oil seal 135. This arrangement prevents leakage of antifreeze.

[0038] It can be understood that a sealed cavity structure is also provided between the rod portion 84 and the control box 86 to prevent leakage of the antifreeze liquid.

[0039] 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 is lifted to a height exceeding a threshold due to the negative pressure in the tank body, the top plate 14 lifts the upper diaphragm 5 to separate it from the valve seat 101, and the air outlet 7 is used to inhale, thereby increasing the upper limit of the high pressure resistance of the breathing valve.

[0040] like Figure 7 As shown, the control method applied to the antifreeze and anti-crystallization hydraulic breathing valve includes the following steps: Step S1: When the tank is at normal pressure, the antifreeze liquid 6 at the target liquid level is input into the upper valve box 2, the initial position of the extension rod 50 is obtained by the first displacement sensor 11, and the initial position of the rod portion 84 is obtained by the second displacement sensor 12; Step S2: Obtain the axial displacement of the extension rod 50 in real time through the first displacement sensor 11 The axial displacement of the rod 84 is obtained in real time by the second displacement sensor 12 ; Step S3: Determine whether the axial displacement of the extension rod 50 is less than a displacement determination threshold, which is generally 0.3 mm to 0.5 mm, preferably 0.5 mm. If it is less than the displacement determination threshold, the current liquid level of the antifreeze liquid 6 is obtained based on the axial displacement of the rod 84; If it is greater than the displacement determination threshold, the actual liquid level is calculated based on the axial displacement of the rod portion 84 and the axial displacement of the extension rod 50; In this way, only single sensor data is required under most working conditions (such as steady-state pressure), reducing the processor load and shortening the response cycle; secondly, small displacements, such as micro-tremors of the upper diaphragm caused by temperature fluctuations, do not trigger corrections, preventing control oscillations caused by frequent fluctuations in the liquid level.

[0041] Specifically, when calculating the actual liquid level, the liquid level correction caused by the displacement of the upper diaphragm 5 is calculated. , and calculate the actual liquid level based on the axial displacement of the rod 84 and the liquid level correction, wherein the liquid level correction is the axial displacement of the extension rod 50 and the effective cross-sectional area of ​​the upper diaphragm 5 The product of the effective cross-sectional area of ​​the upper valve box 2 ratio.

[0042] Among them, the liquid level correction amount The calculation formula is: ; Compared with the axial displacement of the extension rod 50 directly This serves as a correction to avoid overestimating level fluctuations.

[0043] Step S4: Based on the comparison result between the current liquid level and the target liquid level or the comparison result 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, the liquid replenishment program or the liquid discharge program is started.

[0044] The refilling 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 fixed amount of antifreeze liquid 6 flows into the upper valve box 2 through the first regulating valve 92; 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 fixed amount of antifreeze liquid 6 flows out of the upper valve box 2 through the second regulating valve 93 .

[0045] Before the step S4 trigger operation, 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 and replaced with the linear extrapolation value of the most recent valid filtered value and the previous data. The refilling program or the drainage program is started based on the corrected liquid level value.

[0046] In this way, when the liquid level deviation after filtering exceeds the warning value, the abnormal data is replaced by the linear extrapolation value to avoid transient interference triggering erroneous operation.

[0047] The second-order filtering process includes the following steps: Cache sequentially in time Group level value ,in , the sampling interval of each set of data is ; Second-order difference filtering calculation: For each level value , and calculate its second-order derivative estimate: ; Apply the low-pass filter formula to correct the original liquid level value: ; in, Is the filter coefficient, the value range is ,The low-pass filter coefficient balances the response speed and stability, avoiding control misjudgment due to single sampling anomalies.

[0048] Also includes a failsafe mechanism: When the fluctuation frequency and the change rate of the axial displacement of the rod 84 are lower than the preset threshold, it is determined that the rod 84 of the float 83 is stuck or the first sensor is faulty, and the mode is switched to the liquid level estimation mode.

[0049] For example: and ; When the float 83 rod 84 is working normally, it will produce a displacement of a certain frequency with the liquid level fluctuation. If the float 83 rod 84 is stuck, the spectrum 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 judgment criteria (frequency domain + time domain) can distinguish between real sticking and temporary stagnation, greatly reducing the false alarm rate.

[0050] 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: ; The antifreeze liquid 6 is controlled to start a liquid filling procedure or a liquid draining procedure based on the emergency liquid level value.

[0051] In this way, the emergency liquid level value uses the same area ratio parameter as the normal mode, ensuring seamless connection of the main and backup mode data. At the same time, when replacing abnormal data, the linear trend prediction based on the historical effective value is used to avoid control instability caused by algorithm mutation. The main and backup modes share the same physical model, reducing liquid level jumps during mode switching.

[0052] In summary, after reading this detailed disclosure, those skilled in the art will appreciate that the foregoing detailed disclosure may be presented by way of example only and may not be limiting. Although not expressly stated herein, those skilled in the art will understand that the present application requires various reasonable changes, improvements, and modifications to the embodiments. Such changes, improvements, and modifications are intended to be proposed by the present application and are within the spirit and scope of the exemplary embodiments of the present application.

[0053] Furthermore, it should be understood that in the foregoing descriptions of the embodiments of this application, in order to facilitate understanding of a feature and to simplify this application, this application combines various features into a single embodiment, figure, or description thereof. However, this does not mean that the combination of these features is required. When reading this application, it is entirely possible for a person skilled in the art to label some of the devices as separate embodiments. In other words, the embodiments of this application can also be understood as the integration of multiple sub-embodiments. This also applies when the content of each sub-embodiment is less than all the features of a single aforementioned disclosed embodiment.

[0054] Finally, it should be understood that the embodiments of the application disclosed herein are illustrations of the principles of the embodiments of the present application. Other modified embodiments are also within the scope of the present application. Therefore, the embodiments disclosed in the present application are merely examples and not limitations. Those skilled in the art can adopt alternative configurations based on the embodiments in the present application to implement the applications in the present application. Therefore, the embodiments of the present application are not limited to the embodiments precisely described in the application.

Claims

1. Antifreeze and anti-crystallization hydraulic breathing valve, characterized by: The closure of the valve body is opened, and the closure of the valve body is opened, and the closure of the valve body is opened, and the closure of the valve body is opened, and the closure of the valve body is opened, and the closure of the valve body is opened. Under the gravity of the antifreeze liquid, the upper diaphragm and the valve seat form a seal; When the pressure inside the tank is high, the high-pressure gas pushes the upper diaphragm and the valve seat apart, and the high-pressure gas is discharged from the air outlet to achieve exhalation; When the tank is under negative pressure, the external gas enters the lower cavity through the air inlet, lifts up the negative pressure diaphragm and separates the negative pressure valve seat, and enters the tank through the valve cavity to achieve air inhalation.

2. The antifreeze and anti-crystallization hydraulic breathing valve according to claim 1 is characterized in that: A first tube body is provided at the lower end of the upper valve box, and a second tube body is provided at the upper end thereof. The first tube body and the second tube body are arranged in parallel, and a third tube body is vertically arranged therebetween. A float is provided in the third tube body, and a rod is provided on the float to pass through the third tube body and slide axially along the third tube body. A first trigger switch is provided at the upper end of the third tube body, 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.

3. The antifreeze and anti-crystallization hydraulic breathing valve according to claim 2 is characterized in that: A control box is provided at the upper end of the third tube body, and a controller is provided in the control box. The upper end of the rod extends into the control box, the first trigger switch is provided at the bottom of the control box, and the second trigger switch is provided at the upper part of the control box. The upper end of the rod is provided with a second trigger end facing the second trigger switch. When the liquid level in the upper valve box rises, the second trigger end pushes up to trigger the second trigger switch.

4. The antifreeze and anti-crystallization hydraulic breathing valve according to claim 3 is characterized in that: It also includes a liquid replenishing tank, a fourth tube body is provided at the lower part of the upper valve box, a fifth tube body is provided at the upper part thereof, a first regulating valve is provided at the fourth tube body near the upper valve box, a second regulating valve is provided at the fifth tube body near the upper valve box, the liquid replenishing tank is connected to a pump body, and a control valve is provided between the liquid replenishing tank and the pump body, and a reversing valve is provided between the pump body and the fourth tube body and the fifth tube body.

5. The antifreeze and anti-crystallization hydraulic breathing valve according to claim 4 is characterized in that: 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 on the corresponding rod part in the control box.

6. The antifreeze and anti-crystallization hydraulic breathing valve according to claim 5, characterized in that: A sealing cavity is provided on the top of the upper valve box, and the extension rod passes through the sealing cavity. 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, a graphite filler and a lower double-lip oil seal are provided in the upper chamber.

7. The antifreeze and anti-crystallization hydraulic breathing valve according to claim 5, 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 is lifted to a height exceeding a threshold due to the negative pressure in the tank body, the top plate lifts up the upper diaphragm to separate it from the valve seat, and the air outlet is used to inhale air.

8. The control method for the antifreeze and anti-crystallization hydraulic breathing valve according to claim 5, 6 or 7 is characterized in that: The following steps are involved: Step S1: When the tank is under normal pressure, the antifreeze liquid at a target liquid level is input into the upper valve box, the initial position of the extension rod is obtained by the first displacement sensor, and the initial position of the rod portion is obtained by the second displacement sensor; Step S2: obtaining the axial displacement of the extension rod in real time through the first displacement sensor, and obtaining the axial displacement of the rod portion in real time through the second displacement sensor; Step S3: Determine whether the axial displacement of the extension rod is less than a displacement determination threshold: If it is less than the displacement determination threshold, the current liquid level of the antifreeze fluid is obtained based on the axial displacement of the rod; If it is greater than the displacement judgment threshold, the actual liquid 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 liquid level and the target liquid level or the comparison result between the actual liquid level and the target liquid level, if the comparison result exceeds the error range of the target liquid level, the liquid replenishment program or the liquid discharge program is started.

9. The control method of the antifreeze and anti-crystallization hydraulic breathing valve according to claim 8, characterized in that: In step S3, the liquid level correction amount 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 amount, wherein the liquid level correction amount 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.

10. The control method of the antifreeze and anti-crystallization hydraulic breathing valve according to claim 8, characterized in that: Before the triggering operation 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 and replaced with the linear extrapolation value of the most recent valid filtered value and the previous data. The refilling program or the draining program is started based on the corrected liquid level value.

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