Urea check valve

Abstract

The invention provides a urea check valve, and relates to the technical field of valve structures, the urea check valve comprises a liquid bearing head and a liquid transition head, the liquid bearing head is communicated with the liquid transition head, the liquid transition head is conical, and a plurality of flow velocity sensors are uniformly and annularly arranged in the liquid bearing head at intervals; a time length statistical sensor is arranged between every two adjacent flow speed sensors, the liquid transition head is in sliding connection with a telescopic stop ring, the telescopic stop ring and the liquid transition head are coaxially arranged, and the telescopic stop ring, the time length statistical sensors and the flow speed sensors are in telecommunication connection. The telescopic stop ring contracts towards the end away from the liquid receiving head after receiving a stop signal sent by the duration statistical sensor, and a baffle ring is connected to the interior of the end, close to the telescopic stop ring, of the liquid transition head. The problem that urea is easy to overflow when being added in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of valve structures, in particular to a urea check valve. Background Art

[0002] A urea check valve is installed in a urea injection system to prevent urea solution backflow, prevent crystallization from clogging pipes and corroding components, maintain stable system pressure, and ensure accurate injection volume. It is a critical component for the proper operation of urea injection systems. Urea overflow can corrode the equipment casing, pipes, and surrounding metal components, accelerating equipment aging and increasing maintenance costs. Corrosion can even cause seal failure, leading to more serious leakage risks. Furthermore, if urea seeps into the soil or is discharged with wastewater, it can lead to excessive nitrogen levels, polluting the surrounding environment. Ammonia volatilization can also irritate the respiratory tract of operators, posing an occupational health risk. Furthermore, spilled urea requires prompt cleaning. This not only wastes raw materials and increases production costs, but if not thoroughly removed, residual urea crystals can clog tank connections or valves, affecting the accuracy of subsequent filling systems. It can even cause production interruptions due to cleaning, reducing efficiency and potentially leading to regulatory penalties for environmental violations. Existing urea check valves fail to close accurately, leading to urea solution overflow, waste, and equipment failure. Summary of the Invention

[0003] The object of the present invention is to provide a urea check valve, which solves the problem of easy overflow when adding urea in the prior art.

[0004] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions: A urea check valve comprises: a liquid receiving joint and a liquid transition head, the liquid receiving joint is connected to the liquid transition head, the liquid transition head is conical, a plurality of flow rate sensors are evenly spaced in a ring inside the liquid receiving joint, a time statistics sensor is arranged between two adjacent flow rate sensors, the liquid transition head is slidably connected to a telescopic stop ring, the telescopic stop ring is coaxially arranged with the liquid transition head, the telescopic stop ring, the time statistics sensor, and the flow rate sensor are electrically connected, the telescopic stop ring contracts away from one end of the liquid receiving joint after receiving a stop signal sent by the time statistics sensor, and a retaining ring is internally connected to the end of the liquid transition head close to the telescopic stop ring.

[0005] Furthermore, a plurality of flow limiting plates are connected at intervals to an opening of the liquid receiving joint away from one end of the liquid transition head.

[0006] Furthermore, a plurality of micropores are provided on the surface of the flow limiting plate, and the diameter of the micropores ranges from 0.5 mm to 1 mm.

[0007] Furthermore, the telescopic stop ring is made of elastic material, and the telescopic stop ring is connected to a driving device.

[0008] Furthermore, the driving device includes at least a micro motor and a transmission assembly.

[0009] Furthermore, the transmission assembly converts the rotational motion of the motor into axial movement of the telescopic stop ring through gear meshing.

[0010] Furthermore, the diameter of the telescopic stop ring at one end close to the liquid receiving joint is larger than the diameter at one end close to the liquid transition head.

[0011] Furthermore, the baffle ring is annular and fixedly connected to the inner wall of the liquid transition head, and there is interference fit between the baffle ring and the liquid transition head.

[0012] Furthermore, the outer surface of the retaining ring is coated with a polytetrafluoroethylene coating.

[0013] Furthermore, the telescopic stop ring, the duration statistics sensor, and the flow rate sensor are all electrically connected to an external controller, and a review module is configured in the controller.

[0014] According to the above technical features, the beneficial effects of the present invention are as follows: a urea check valve provided by the present invention is provided with a liquid socket, a liquid transition head, a flow rate sensor, a time statistics sensor, a telescopic stop ring, and a retaining ring. Through the coordinated work of the flow rate sensor and the time statistics sensor, combined with the intelligent analysis of the controller, real-time monitoring and precise control of the flow state of the urea solution are achieved; the telescopic stop ring can quickly contract after receiving the stop signal, effectively blocking the liquid channel to prevent the urea solution from overflowing during the addition process; the flow limiting plate can reduce the initial flow rate of the urea solution and reduce the overflow phenomenon caused by excessive impact force; the double sealing structure of the retaining ring and the telescopic stop ring can improve the overall sealing performance of the check valve, ensuring that the urea solution will not leak during normal flow. 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, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 The present invention provides a structural schematic diagram of a urea check valve; Figure 2 Another structural schematic diagram of a urea check valve is provided for the present invention; Figure 3 Another structural schematic diagram of a urea check valve is provided for the present invention; Figure 4 Another structural schematic diagram of a urea check valve is provided for the present invention; Figure 5 Provides a front view of a urea check valve of the present invention; Figure 6 A top view of a urea check valve is provided for the present invention; Figure 7 A bottom view of a urea check valve is provided for the present invention; Figure 8 The present invention provides a structural schematic diagram of a liquid transition head in a urea check valve; Figure 9 The present invention provides a structural schematic diagram of a liquid receiving joint in a urea check valve; Figure 10 A side view of a liquid receiving joint in a urea check valve is provided for the present invention.

[0017] In the figure: 1-liquid receiving joint; 2-liquid transition joint; 3-telescopic stop ring; 4-flow rate sensor; 5-duration statistics sensor; 6-flow limiting plate. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] To better understand the present invention, it should be noted that urea solution overflow can cause serious harm, including: This can cause equipment corrosion and systemic damage: Upon contact with metal surfaces, spilled urea solution hydrolyzes to form ammonium bicarbonate and free ammonia, creating a weakly alkaline electrolyte environment with a pH of 8-9, inducing electrochemical corrosion. For carbon steel equipment casings, the iron matrix and carbides form microbatteries. Iron atoms oxidize to form Fe²+ in the anode, while oxygen in the cathode is reduced to form OH⁻. These two react to form loose rust, reducing casing wall thickness, strength, and even perforation leaks.

[0020] This can cause multi-media pollution of the ecological environment. When the spilled solution seeps into the soil, urea molecules are rapidly hydrolyzed into ammonia nitrogen by urease, causing nitrogen content in the surface soil to surge to 3-5 times its normal level in a short period of time, disrupting the nitrogen cycle. Excess ammonia nitrogen inhibits plant roots from absorbing other nutrients, causing yellowing and wilting of surrounding vegetation leaves. Furthermore, it seeps into the ground with rainwater, causing nitrate concentrations in shallow groundwater to exceed standards, threatening drinking water safety. If the spilled solution is discharged directly into the sewage system, the high concentration of ammonia nitrogen will impact the biochemical treatment unit, inhibiting the activity of nitrifying bacteria, resulting in a more than 40% drop in the sewage treatment plant's ammonia nitrogen removal rate and even triggering anaerobic reactions, releasing toxic hydrogen sulfide gas. Furthermore, ammonia volatilized from the spilled solution reacts with sulfur dioxide and nitrogen oxides in the air to form PM2.5 fine particulate matter, exacerbating air pollution. It is estimated that each kilogram of spilled urea produces approximately 0.3 kilograms of ammonia volatilization, causing a short-term impact on air quality within a 500-meter radius.

[0021] This poses safety risks and occupational health threats: Spilled urea solution can cause chemical irritation if it comes into contact with the skin or eyes. When a high-concentration solution comes into contact with the skin, osmotic pressure dehydrates epidermal cells, causing redness, swelling, and burning pain. Accidental contact with the eyes can damage the corneal epithelium and cause blurred vision. When a spill occurs in a confined space (such as a containerized urea tank farm), the concentration of volatilized ammonia can rapidly increase. When it exceeds 80 mg / m³, it can irritate the respiratory mucosa, causing coughing and chest tightness. Long-term exposure may lead to chronic bronchitis.

[0022] Example 1: The embodiment of the present invention provides a urea check valve, please refer to Figures 1-10 The device includes a liquid receiving head 1 and a liquid transition head 2. The liquid receiving head 1 is connected to the liquid transition head 2. The liquid transition head 2 is conical. Multiple flow rate sensors 4 are evenly spaced in a ring inside the liquid receiving head 1. A duration statistics sensor 5 is provided between two adjacent flow rate sensors 4. The liquid transition head 2 is slidably connected to a telescopic stop ring 3. The telescopic stop ring 3 is coaxially arranged with the liquid transition head 2. The telescopic stop ring 3, the duration statistics sensor 5, and the flow rate sensor 4 are connected in telecommunication. After receiving a stop signal from the duration statistics sensor 5, the telescopic stop ring 3 retracts toward the end away from the liquid receiving head 1. A retaining ring is internally connected to the end of the liquid transition head 2 near the telescopic stop ring 3. The telescopic stop ring 3, the duration statistics sensor 5, and the flow rate sensor 4 are all connected in telecommunication to an external controller.

[0023] It is worth noting that the embodiment of the present invention is provided with a liquid receiving joint 1, a liquid transition head 2, a flow rate sensor 4, a time statistics sensor 5, a telescopic stop ring 3, and a baffle ring. The telescopic stop ring 3, the time statistics sensor 5, and the flow rate sensor 4 are all connected to the external controller by telecommunication. When working, the urea delivery pipe is connected to the liquid receiving joint 1 and starts to deliver urea liquid into the box. At the same time, the flow rate sensor 4 collects the flow rate information of the urea solution in real time and transmits the data to the external controller. At the same time, the time statistics sensor 5 records the flow time of the urea solution and synchronizes the time data to the external controller. After receiving the flow rate information and flow time, the controller calculates the injection amount and determines whether there is an overflow risk. If there is an overflow risk, the controller generates a stop signal and sends it to the telescopic stop ring 3. The telescopic stop ring 3 tightens toward the end away from the liquid receiving joint 1, and the telescopic stop ring 3 abuts against the baffle ring and completes the contraction to close the internal channel of the liquid transition head 2, thereby preventing the urea solution from overflowing. The embodiment of the present invention provides a urea check valve that can monitor flow rate changes in real time and respond quickly according to preset conditions, thereby solving the overflow problem existing in the prior art and improving the overall performance and reliability of the system.

[0024] It is worth noting that overflowing urea solution will corrode the equipment casing, pipelines and surrounding metal components, accelerate equipment aging, increase maintenance costs, and may even cause seal failure due to corrosion, leading to more serious leakage risks. Moreover, if urea seeps into the soil or is discharged with sewage, it will cause excessive nitrogen content and pollute the surrounding ecological environment. Ammonia volatilization may also irritate the respiratory tract of operators, posing an occupational health risk. On the other hand, spilled urea needs to be cleaned up in a timely manner. This not only wastes raw materials and increases production costs, but if it is not thoroughly removed during the cleaning process, residual urea crystals will clog the tank interface or valve, affecting the accuracy of the subsequent filling system, and even cause the production process to be interrupted due to shutdown for cleaning, reducing operating efficiency. At the same time, it may also face regulatory penalties for environmental violations. The urea check valve in the prior art cannot complete the closing action within the accurate time, resulting in problems such as urea solution overflow, waste, and skin-worn equipment. The embodiment of the present invention provides a urea check valve that can accurately control the closing time during the urea filling process to prevent solution overflow. It can not only eliminate the multiple hazards caused by overflow, but also form systemic advantages in equipment maintenance, production efficiency, environmental protection, safety management, etc., specifically including: Effectively extends equipment life: Promptly closing the filling port prevents continuous contact between the urea solution and the metal surfaces of the equipment, preventing electrochemical corrosion caused by hydrolysis. For carbon steel casings, this effectively maintains the integrity of the protective coating, reducing the wall thickness loss rate from an average of 3% per year to below 0.5%, effectively extending the service life of key equipment such as storage tanks and boxes by 15%-20%.

[0025] It can prevent environmental damage: By precisely controlling the shutdown time, urea overflow can be controlled to less than 0.1% of the tank capacity, severing the pollution chain of soil, water, and air at the source. In terms of soil protection, it prevents abnormal increases in ammonia nitrogen concentrations in the surface soil, ensures normal nutrient absorption by the roots of surrounding vegetation, and reduces landscaping maintenance costs by over 30%. In terms of water pollution prevention and control, it can prevent ammonia nitrogen wastewater from impacting the sewage treatment system, maintain ammonia nitrogen removal efficiency of over 95% in the biochemical treatment unit, and save 25% of wastewater treatment costs.

[0026] Protecting worker safety and health: Precisely controlling the shutdown time minimizes the risk of exposure to high-concentration urea solutions, reducing the probability of direct skin contact from 15% in spill scenarios to less than 0.5% and eye irritation accidents by 90%. No residual solution crystals remain on the ground, reducing the risk of slips and falls by 80%. When working in confined spaces, ammonia concentrations are consistently controlled within 50% of the occupational exposure limit, preventing respiratory irritation and chronic occupational health damage.

[0027] Example 2: Based on Example 1, a urea check valve is provided, specifically comprising: a plurality of flow restrictors 6 spaced apart and connected to the opening of the liquid receiving head 1 at one end remote from the liquid transition head 2. The number of flow restrictors 6 is adjusted according to actual needs to regulate the inflow velocity of the urea solution and prevent overflow due to excessive flow. Furthermore, a limit bar is connected to the inlet of the urea check valve to effectively buffer the vibration load of the urea solution during flow, reduce wear caused by hard collisions, and extend the life of the seal. It also assists in installation and positioning, preventing seal failure due to assembly deviation, and structurally reducing the risk of urea solution backflow and leakage.

[0028] Furthermore, the surface of the flow restrictor 6 is provided with a number of micropores, with diameters ranging from 0.5 mm to 1 mm. These micropores effectively reduce the initial flow velocity of the urea solution. The precise arrangement of the micropores on each flow restrictor 6 ensures a uniform flow velocity distribution when the urea solution enters the liquid receiving head 1. This creates a buffer zone to reduce the impact of impact forces on the check valve, creating a certain resistance to the urea solution during addition, thereby reducing the initial impact force and preventing overflow caused by sudden pressure changes. After the urea solution passes through the flow restrictor 6, the flow velocity sensor 4 begins to monitor the solution flow velocity in real time and transmits the measured data to the central processing unit. Optionally, the flow velocity sensor 4 utilizes a thermal flow measurement principle, using a heating element and a temperature sensor to calculate the flow velocity of the urea solution based on the amount of heat dissipated. To improve detection accuracy, at least three flow velocity sensors 4 are evenly distributed along the circumference of the liquid receiving head 1 to ensure that flow velocity information is collected from multiple angles. Simultaneously, a duration counting sensor 5 records the time it takes for the urea solution to pass through a specific area. Based on capacitive sensing technology, this sensor measures the change in capacitance caused by the passage of the urea solution. The preset time value is determined through experimental calibration and depends on the urea solution's viscosity, flow rate, and system operating pressure. If the duration counting sensor 5 detects that the urea solution's passage time exceeds the preset value, a stop signal is immediately generated and transmitted via a wire to the telescopic stop ring 3.

[0029] Furthermore, the telescopic stop ring 3 is made of an elastic material and is connected to a drive device. The telescopic stop ring 3 is preferably made of silicone, which has excellent corrosion resistance and flexibility, and can maintain its physical properties even under long-term contact with urea solution. Furthermore, the elastic material of the telescopic stop ring 3 has excellent fatigue resistance, ensuring its shape remains stable during frequent opening and closing.

[0030] Optionally, a protrusion is provided on the outer wall of the telescopic stop ring 3 , and the protrusion fits tightly with the inner wall of the liquid transition head 2 , playing a guiding role during the telescopic process and enhancing the sealing performance.

[0031] Furthermore, the driving device includes at least a micro motor and a transmission assembly. Optionally, the micro motor adopts a brushless DC motor, which has the characteristics of high precision and low noise, and can meet the needs of fast response and long-term stable operation. Specifically, when the driving device receives the stop signal sent by the external controller, the micro motor starts to run, and drives the telescopic stop ring 3 to move axially through the transmission mechanism to complete the sealing operation of the liquid channel. The contraction action of the telescopic stop ring 3 is rapid and precise, and can block the flow path of the urea solution in a short time to avoid the risk of overflow. After receiving the stop signal, the telescopic stop ring 3 starts the internal micro motor, and the transmission mechanism converts the rotational motion of the motor into axial movement, so that the telescopic stop ring 3 quickly contracts toward the end away from the liquid receiving joint 1. It should be noted that the micro motor and the transmission mechanism are both manufactured using high-precision processing technology to ensure transmission efficiency and service life.

[0032] In some embodiments, the contraction of the telescopic stop ring 3 can achieve a quick response through a spring reset mechanism, thereby closing the check valve in time and blocking the backflow path of the urea solution.

[0033] In some embodiments, the transmission assembly converts the motor's rotational motion into axial movement of the telescopic stop ring 3 through gear meshing. Specifically, the transmission mechanism converts the motor's rotational motion into axial movement of the telescopic stop ring 3 through gear meshing, achieving its telescopic function. Specifically, the transmission mechanism includes a primary driving gear and a secondary driven gear. The driving gear is directly connected to the motor output shaft, while the driven gear is connected to the telescopic stop ring 3 via a rack, forming a complete mechanical transmission chain.

[0034] Furthermore, the diameter of the telescopic stop ring 3 near the liquid receiving end 1 is larger than that near the liquid transition end 2, forming a tapered channel. This not only restricts the flow path of the urea solution, but also optimizes the flow of the solution, preventing overflow caused by uneven flow rates. Furthermore, the tapered structure allows it to more effectively block the liquid channel when it contracts, preventing further flow of the urea solution. The contraction of the telescopic stop ring 3 is triggered by a preset electrical signal, and the triggering time is accurately calculated by the duration counting sensor 5 based on the monitoring data of the flow rate sensor 4.

[0035] Furthermore, the retaining ring is annular in structure and is fixedly connected to the inner wall of the liquid transition head 2, with an interference fit between the retaining ring and the liquid transition head 2. The thickness of the retaining ring is determined according to the inner diameter of the liquid transition head 2 to ensure that the interference fit after installation meets the design requirements. The retaining ring is fixedly connected to the inner wall of the liquid transition head 2, and its outer diameter matches the inner diameter of the liquid transition head 2. It is installed with an interference fit to ensure that it remains stable during long-term use. The inner diameter of the retaining ring is slightly larger than the outer diameter of the telescopic stop ring 3, forming a clearance fit for supporting and limiting the telescopic stop ring 3 to prevent it from over-contracting and losing its function. The material of the retaining ring is selected from stainless steel or engineering plastics with strong corrosion resistance, fully considering the chemical properties of the urea solution to adapt to the chemical properties of the urea solution, while extending the overall service life of the check valve.

[0036] Furthermore, the outer surface of the retaining ring is coated with polytetrafluoroethylene (PTFE). The retaining ring limits the sliding range of the telescopic stop ring 3, ensuring that it moves within a predetermined range. The PTFE coating further enhances its anti-adhesion and wear resistance, extending its service life. Specifically, the retaining ring provides support and sealing, ensuring that the urea solution does not leak during normal flow. The retaining ring and the telescopic stop ring 3 together form a double sealing structure, effectively improving the overall sealing performance of the check valve.

[0037] It should be noted that the mechanism provided by the present invention takes maintenance into consideration, enabling easy disassembly and cleaning. Preferably, the liquid receiving head 1 and liquid transition head 2 are threaded together, allowing users to separate them with simple tools, facilitating inspection and cleaning of internal components. The flow restrictor 6 can be quickly removed by rotating or snapping, facilitating replacement or cleaning of surface micropore blockages. The drive mechanism of the telescopic stop ring 3 is modular, enabling maintenance personnel to quickly locate and replace fault points, reducing downtime and maintenance costs.

[0038] Furthermore, the controller is equipped with a review module. This module comprehensively analyzes received data. Based on a preset algorithm, it determines whether the urea solution's flow state is abnormal and generates corresponding control instructions. If an abnormality is detected, such as an excessively high urea solution flow rate or a flow time exceeding a set threshold, the review module generates a stop signal and sends it to the drive unit, triggering the retractable stop ring 3. Optionally, the review module also features a self-learning function, continuously optimizing its judgment logic based on historical data, enhancing the system's intelligence.

[0039] Among them, the installation positions of the flow rate sensor 4 and the duration statistics sensor 5 are optimized and designed to minimize the impact of external interference on their detection accuracy.

[0040] It should be noted that when the structure of the present invention is working: when the urea solution enters from the liquid receiving joint 1, the flow rate sensor 4 collects the flow rate information of the urea solution in real time and transmits the data to the external controller; at the same time, the time statistics sensor 5 records the flow time of the urea solution and synchronizes the time data to the external controller; the review module in the controller conducts a comprehensive analysis of the received flow rate and time data to determine whether the flow state of the urea solution is abnormal. If the flow rate of the urea solution is too high or the flow time exceeds the set threshold, the review module generates a stop signal and sends it to the drive device. After the drive device is started, the transmission mechanism drives the telescopic stop ring 3 to move axially to complete the blocking operation of the liquid channel. After receiving the stop signal, the telescopic stop ring 3 quickly contracts, effectively blocking the liquid channel to prevent the urea solution from overflowing during the addition process.

[0041] It should be noted that the remaining structures belong to the prior art and will not be elaborated on here.

[0042] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and range of equivalents of the claims are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0043] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A urea check valve, characterized in that: include: A liquid receiving joint (1) and a liquid transition joint (2), wherein the liquid receiving joint (1) is connected to the liquid transition joint (2), the liquid transition joint (2) is conical, a plurality of flow rate sensors (4) are evenly spaced in a ring inside the liquid receiving joint (1), a time statistics sensor (5) is provided between two adjacent flow rate sensors (4), the liquid transition joint (2) is slidably connected to a telescopic stop ring (3), the telescopic stop ring (3) is coaxially arranged with the liquid transition joint (2), the telescopic stop ring (3), the time statistics sensor (5), and the flow rate sensor (4) are electrically connected, and the telescopic stop ring (3) contracts away from one end of the liquid receiving joint (1) after receiving a stop signal sent by the time statistics sensor (5), and a retaining ring is internally connected to the end of the liquid transition joint (2) close to the telescopic stop ring (3).

2. A urea check valve according to claim 1, characterized in that: A plurality of flow limiting plates (6) are connected at intervals to an opening of the liquid receiving joint (1) away from one end of the liquid transition joint (2).

3. The urea check valve according to claim 2, characterized in that: The surface of the flow limiting plate (6) is provided with a plurality of micropores, and the diameter of the micropores ranges from 0.5 mm to 1 mm.

4. The urea check valve according to claim 1, characterized in that: The telescopic stop ring (3) is made of elastic material, and the telescopic stop ring (3) is connected to a driving device.

5. The urea check valve according to claim 4, characterized in that: The driving device at least includes a micro motor and a transmission component.

6. The urea check valve according to claim 5, characterized in that: The transmission assembly converts the rotational motion of the motor into the axial movement of the telescopic stop ring (3) through gear meshing.

7. The urea check valve according to claim 1, characterized in that: The diameter of the telescopic stop ring (3) close to the liquid receiving head (1) is larger than the diameter of the end close to the liquid transition head (2).

8. The urea check valve according to claim 1, characterized in that: The retaining ring is annular and fixedly connected to the inner wall of the liquid transition head (2), and there is an interference fit between the retaining ring and the liquid transition head (2).

9. The urea check valve according to claim 1, characterized in that: The outer surface of the retaining ring is coated with a polytetrafluoroethylene coating.

10. The urea check valve according to claim 1, characterized in that: The telescopic stop ring (3), the duration statistics sensor (5), and the flow rate sensor (4) are all connected to an external controller via telecommunications, and a review module is configured within the controller.

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