Liquid ammonia liquid level meter capable of automatically cleaning impurities and method

Abstract

The invention relates to the technical field of liquid ammonia liquid level meters, in particular to a liquid ammonia liquid level meter capable of automatically cleaning impurities and a method thereof.The liquid ammonia liquid level meter comprises a sampling pipe and a floating ball liquid level sensor installed in the sampling pipe, the floating ball liquid level sensor is used for detecting the position of a floating ball and the height of the liquid level, and the floating ball liquid level sensor transmits detection data to a processor; a heat tracing pipe is arranged on the outer wall of the sampling pipe, a flow meter for introducing inert gas is arranged at the upper end of the sampling pipe, and a blow-down valve is arranged at the lower end of the sampling pipe. Whether the floating ball is stuck or not is judged by automatically detecting the position of the floating ball, then cleaning is achieved by heating and nitrogen introduction for purging under the condition that the floating ball is stuck, and due to the integrated automation technology, the accuracy of liquid level measurement of liquid ammonia and the stability of the system are remarkably improved. According to the device, impurities attached to the liquid level meter can be removed in time, the floating ball is prevented from being jammed, and accuracy and reliability of liquid level measurement data are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of liquid ammonia level gauges, and in particular to a liquid ammonia level gauge and a method for automatically cleaning impurities. Background Art

[0002] In industrial production, liquid ammonia is usually extracted from coke, and the raw material of coke is coal. Due to the extreme instability and high risk of liquid ammonia, its storage and transportation in industry must be very cautious. The storage equipment accessories of liquid ammonia, especially the selection of liquid level gauges, have extremely high requirements to ensure safety and meet industry standards. Therefore, most of the liquid ammonia level gauges in industry use float type liquid level gauges to improve safety.

[0003] However, although the float type liquid level meter has improved safety, it also has the disadvantages of mechanical measurement. There are too many impurities such as coke in the liquid ammonia, and the temperature of the liquid ammonia is relatively low. These impurities can easily adhere to the sliding rod of the float, causing the float to get stuck and affecting the accuracy of the measurement. Summary of the invention

[0004] In view of the problems existing in the above-mentioned existing liquid ammonia level meter with automatic impurity cleaning, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to provide a liquid ammonia level meter with automatic impurity cleaning, the purpose of which is that: the device can automatically remove and discharge impurities attached to the liquid ammonia level meter, quickly solve the problem of the level meter getting stuck and inaccurate readings, and minimize the impact of the fault.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a liquid ammonia level meter with automatic impurity cleaning, comprising a sampling tube and a float level sensor installed inside the sampling tube, which is used to detect the float position and the liquid level height. The float level sensor transmits the detection data to a processor. A heating pipe is arranged on the outer wall of the sampling tube, and a flow meter for introducing inert gas is arranged at the upper end of the sampling tube, and a drain valve is arranged at the lower end of the sampling tube.

[0007] As a preferred solution of the liquid ammonia level meter with automatic impurity cleaning described in the present invention, a first pneumatic valve is arranged on the upper end of the outer wall of the sampling tube, and a second pneumatic valve is arranged on the lower end, and the first pneumatic valve and the second pneumatic valve are both connected to the liquid ammonia evaporator.

[0008] As a preferred solution of the liquid ammonia level meter with automatic impurity cleaning described in the present invention, a sliding rod is arranged inside the sampling tube, a hole is arranged at the center of the float liquid level sensor, and the float liquid level sensor performs limited lifting and lowering movement along the sliding rod through the hole.

[0009] As a preferred solution of the liquid ammonia level meter with automatic impurity cleaning of the present invention, the processor is connected with the float level sensor, flow meter, drain valve, heating pipe, first pneumatic valve and second pneumatic valve.

[0010] As a preferred solution of the liquid ammonia level meter with automatic impurity cleaning of the present invention, the processor and the single-chip microcomputer are the main controllers, which are used to receive the signal of the float liquid level sensor and control the flow meter, the drain valve, the heating pipe, the first pneumatic valve and the second pneumatic valve to execute.

[0011] It includes a communication module for remote monitoring and control, and can integrate a wireless communication module (such as Wi-Fi, Bluetooth, 4G, etc.) for the transmission of data and control fingers;

[0012] The analog-to-digital conversion module converts the analog signal into a digital signal;

[0013] The timing module is used to time the duration of the state where the liquid level does not change;

[0014] The logic judgment module determines that the level meter is stuck when the liquid level reading fluctuates within a set very small range or remains unchanged for more than 120 seconds;

[0015] The display module is used for human-computer interaction, showing the current liquid level and status, and issuing an audible and visual alarm when the liquid level gauge is detected to be stuck.

[0016] As a preferred solution of the liquid ammonia level meter with automatic impurity cleaning of the present invention, the heating pipe is wrapped around the outer wall of the sampling tube and has a built-in heating wire.

[0017] As a preferred solution of the liquid ammonia level meter with automatic impurity cleaning described in the present invention, the flow meter is used to control the time of the inert gas introduction, and the inert gas is nitrogen.

[0018] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for automatically cleaning impurities of a liquid ammonia level gauge, comprising the liquid ammonia level gauge for automatically cleaning impurities, and,

[0019] Close the first pneumatic valve and the second pneumatic valve to cut off the connection between the sampling tube and the liquid ammonia evaporator;

[0020] The float liquid level sensor detects and times the liquid level in real time. When the float is stuck, the liquid level feedback reading remains unchanged or fluctuates within a very small range. The float liquid level sensor sends the data to the processor.

[0021] After receiving the information, the processor starts the heating pipe to heat the sampling pipe;

[0022] When the temperature reaches the preset value, nitrogen is injected into the sampling tube through the flow meter and the drain valve is opened;

[0023] Stop heating, turn off the flow meter, stop injecting nitrogen, close the drain valve, open the first pneumatic valve and the second pneumatic valve, and reconnect the sampling tube and the liquid ammonia evaporator.

[0024] As a preferred solution of the method for automatically cleaning impurities in the liquid ammonia level gauge of the present invention, the inside of the sleeve is heated to above 65° C. before cleaning.

[0025] As a preferred solution of the method for automatically cleaning impurities in the liquid ammonia level gauge of the present invention, after the temperature is met, an inert gas is introduced and the drain valve is opened synchronously, and the purge is completed for 30 seconds.

[0026] Beneficial effects of the present invention: The liquid ammonia level meter with automatic impurity cleaning of the present invention can automatically detect the position of the float to determine whether the float is stuck, and then clean it by heating and introducing nitrogen to purge it in the case of a stuck column. This integrated automation technology significantly improves the accuracy of liquid ammonia level measurement and the stability of the system. The device can timely remove impurities attached to the level meter, prevent the float from getting stuck, and ensure the accuracy and reliability of the liquid level measurement data. The automated cleaning process reduces manual intervention, effectively reduces maintenance costs and production interruption losses caused by maintenance, and reduces the need for personnel to enter dangerous production sites, significantly improves operational safety, and ensures the personal safety of operators. In addition, the device improves the reliability of the liquid ammonia level meter, reduces the failure rate of the measuring device caused by impurities, and saves overall cost expenditures. The design of the device is simple to implement, and uses common industrial components such as signal acquisition systems and steam heating pipes without the need for additional complex equipment investment to achieve fully automated impurity cleaning. It meets the high requirements of the industry for the safety and accuracy of liquid ammonia level meters, and helps to improve the safety and operating standards of the entire industry. Through effective impurity management, potential pollution to the environment caused by improper impurity cleaning is reduced, reflecting the environmentally friendly characteristics. The method has strong adaptability and is suitable for liquid ammonia level meters under various working conditions, with strong adaptability and flexibility. In general, the present invention not only improves the operating efficiency of the liquid ammonia evaporation system, but also reduces the operating risks, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 The figure is a schematic diagram of the installation structure of the liquid ammonia level meter with automatic impurity cleaning according to the present invention.

[0029] Figure 2 The figure is a schematic diagram of the overall structure of the liquid ammonia level meter with automatic impurity cleaning according to the present invention.

[0030] Figure 3 The figure is a schematic diagram of the cross-sectional structure of the liquid ammonia level meter with automatic impurity cleaning according to the present invention.

[0031] In the figure:

[0032] 100. Sampling tube; 200. Float liquid level sensor; 300. Processor; 400. Heat tracing pipe; 500. Flow meter; 600. Drain valve; 700. First pneumatic valve; 800. Second pneumatic valve; 900. Liquid ammonia evaporator. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0036] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0037] Example 1

[0038] Reference Figure 1-Figure 3, which is the first embodiment of the present invention, provides a liquid ammonia level meter with automatic impurity cleaning, including a sampling tube 100 and a float liquid level sensor 200 installed inside the sampling tube 100, which is used to detect the float position and liquid level height. The float liquid level sensor 200 transmits the detection data to the processor 300. A heating pipe 400 is arranged on the outer wall of the sampling tube 100, and a flow meter 500 for introducing inert gas is arranged at the upper end of the sampling tube 100, and a drain valve 600 is arranged at the lower end of the sampling tube 100. A first pneumatic valve 700 is arranged on the upper end of the outer wall of the sampling tube 100, and a second pneumatic valve 800 is arranged on the lower end. The first pneumatic valve 700 and the second pneumatic valve 800 are both connected to the liquid ammonia evaporator 900. The heating pipe 400 is wrapped around the outer wall of the sampling tube 100, and has a built-in electric heating wire. The flow meter 500 is used to control the time of inert gas introduction, and the inert gas is nitrogen.

[0039] The liquid ammonia level meter with automatic impurity cleaning of the present invention realizes efficient automatic cleaning of impurities in the level meter through a series of carefully designed systems, thereby ensuring the accuracy of liquid level measurement and the stability of the liquid ammonia evaporation system. The core components of the device include two precisely controlled pneumatic valves, namely the first pneumatic valve 700 and the second pneumatic valve 800, which are responsible for cutting off and restoring the connection between the sampling tube 100 and the liquid ammonia evaporator 900. The liquid level detection and feedback system adopts a high-precision float liquid level sensor 200 to monitor the liquid level change in real time and send the data to the processor 300. The processor 300 determines whether the float is stuck according to a preset algorithm. If the liquid level reading fluctuates or remains unchanged within a very small range for a certain period of time, it will be judged that the liquid level meter is stuck and the heating pipe 400 will be started. The heating pipe 400 adopts electric heating to ensure that the temperature in the sampling tube 100 is evenly increased to above 65°C to soften the impurities attached to the float sliding rod.

[0040] Once the temperature reaches the preset value, the nitrogen injection and drainage system injects nitrogen into the sampling tube 100 through the flow meter 500, and opens the drainage valve 600 for purging. The nitrogen purge lasts for 30 seconds to effectively remove impurities, and then closes the drainage valve 600 and the flow meter 500 to stop nitrogen injection. Finally, open the first pneumatic valve 700 and the second pneumatic valve 800, reconnect the sampling tube 100 and the liquid ammonia evaporator 900, and resume normal liquid level measurement.

[0041] To ensure the safety of the entire cleaning process, the device can be further equipped with a safety monitoring system, including temperature, pressure monitoring and leak detection. The entire cleaning process can be automatically controlled by PLC (Programmable Logic Controller) to achieve unattended operation, further improving the flexibility and safety of the operation. In addition, the integrated remote monitoring and operation function enables operators to monitor and control the entire cleaning process from a safe location, reducing the need for personnel to enter dangerous production sites while ensuring the safety of operators.

[0042] In summary, the automatic cleaning device of the present invention can realize fully automated cleaning of impurities in the casing of the liquid ammonia level gauge with extremely small investment by using common industrial components, thereby reducing the failure rate of the liquid ammonia evaporator 900 level measuring device, reducing maintenance costs and operational risks, and having significant economic and social benefits.

[0043] A sliding rod is arranged inside the sampling tube 100 , and a hole is arranged at the center of the float liquid level sensor 200 . The float liquid level sensor 200 performs a limited lifting and lowering movement along the sliding rod through the hole.

[0044] It should be noted that the float level sensor 200 uses the principle of buoyancy to detect the liquid level in a container or tank. This sensor usually consists of the following main parts: The float is the core component of the sensor, usually made of lightweight and corrosion-resistant materials, and can float freely in the liquid. The buoyancy of the float enables it to move up and down as the liquid level rises and falls. The sliding rod (or float arm) connects the float to the internal mechanical or electronic components of the sensor, and the up and down movement of the float is transmitted to the internal mechanism of the sensor through the sliding rod. Mechanical or electronic conversion mechanism: Depending on the position of the float, this mechanism will convert into a corresponding mechanical or electronic signal. In a mechanical float level sensor 200, this usually involves a lever and gear system, while in an electronic float level sensor 200, it may involve a potentiometer or other electronic sensor. Indicator or output device: In a mechanical float level sensor 200, the indicator may be a simple dashboard that shows the height of the liquid level. In an electronic float level sensor 200, the output device may be a digital display or a signal output connected to a control system for remote monitoring or automatic control.

[0045] The working principle of the float liquid level sensor 200 is: when the liquid level rises, the float floats up, and the sliding rod drives the mechanical or electronic conversion mechanism to generate a corresponding signal output; when the liquid level drops, the float sinks, and the sliding rod also drives the mechanism to change the output signal. In this way, the sensor can accurately reflect the change of the liquid level according to the position of the float.

[0046] The advantages of the float level sensor 200 include: simple structure and easy maintenance. It is suitable for various liquid media, including corrosive liquids. It can provide high-precision liquid level measurement. However, the float level sensor 200 also has some limitations, such as: the float or the sliding rod may get stuck due to impurities in the liquid, affecting the accuracy of the measurement. In high-viscosity liquids, the movement of the float may be restricted. Regular cleaning and maintenance are required to prevent the accumulation of impurities.

[0047] In the application of liquid ammonia level meter, since liquid ammonia may contain impurities, as mentioned above, the float level sensor 200 may be affected, causing the float to get stuck. Therefore, regular cleaning and maintenance are very important, which is why an automatic cleaning device needs to be designed to maintain the accuracy and reliability of the sensor.

[0048] The processor 300 is connected with the float liquid level sensor 200, the flow meter 500, the drain valve 600, the heat tracing pipe 400, the first pneumatic valve 700 and the second pneumatic valve 800. The processor 300 and the single chip microcomputer are the main controllers, which are used to receive the signal of the float liquid level sensor 200 and control the flow meter 500, the drain valve 600, the heat tracing pipe 400, the first pneumatic valve 700 and the second pneumatic valve 800 to perform. It includes a communication module for remote monitoring and control, which can integrate a wireless communication module (such as Wi-Fi, Bluetooth, 4G, etc.) to transmit data and control instructions; an analog-to-digital conversion module converts analog signals into digital signals; a timing module is used to time the duration of the state of no change in the liquid level; a logic judgment module, when the liquid level reading fluctuates within a set very small range or remains unchanged for more than 120 seconds, it is judged that the liquid level meter is stuck; a display module is used for human-computer interaction, displays the current liquid level and status, and issues an audible and visual alarm when the liquid level meter is detected to be stuck.

[0049] The processor 300 plays a core control and coordination role. It usually consists of a single-chip microcomputer (MCU) as the main controller, responsible for the monitoring and operation of the entire system. Through the collaborative work of these modules, the processor 300 can achieve precise control and monitoring of the liquid ammonia level meter with automatic impurity cleaning, ensure the accuracy of the level meter and the stability of the system, and improve the safety and efficiency of the operation. The following is a detailed explanation of the processor 300:

[0050] 1. Single chip microcomputer (MCU) main controller, which is a microcomputer integrating CPU, memory, input / output interface. Here, it is responsible for receiving the signal from the float liquid level sensor 200 and controlling the operation of other devices (such as flow meter 500, drain valve 600, heating pipe 400, first pneumatic valve 700 and second pneumatic valve 800) according to the preset program logic. The single chip microcomputer can be programmed to implement specific control logic, such as timing, logical judgment, signal processing, etc.

[0051] 2. Communication module, the processor 300 integrates a wireless communication module, such as Wi-Fi, Bluetooth, 4G, etc., so that the entire system can also be remotely monitored and controlled. Further, this allows operators to monitor the status of the level meter in a safe location or send control instructions from a remote location.

[0052] 3. The analog-to-digital conversion module (ADC) is used to convert the analog signal of the float liquid level sensor 200 into a digital signal. This is because the microcontroller can only process digital signals, and many sensors (such as some types of float liquid level sensors 200) output analog signals.

[0053] 4. The timing module is used to record the duration of the state of no change in the liquid level. In the case of a stuck liquid level meter, if the liquid level reading fluctuates within a set very small range or remains unchanged for more than a preset time (such as 120 seconds), the timing module will notify the logic judgment module to perform corresponding processing.

[0054] 5. The logic judgment module determines whether the level gauge is stuck based on the level reading and the data from the timing module. If the level reading fluctuates within a set very small range or remains unchanged for more than 120 seconds, the module will determine that the level gauge is stuck and trigger the corresponding cleaning procedure. This module is the brain of the intelligent control system, and it makes decisions based on real-time data and preset conditions.

[0055] 6. The display module is used to display the current liquid level and system status, providing an intuitive operation interface. When the liquid level meter is detected to be stuck, the display module will also issue an audible and visual alarm to remind the operator to take appropriate measures.

[0056] Among them, the introduction of inert gas, such as nitrogen, is to create a safe and non-reactive environment during the cleaning process of the level gauge. The characteristics of inert gases are stable chemical properties and are not easy to react with other substances, which enables them to be used in industrial applications to prevent oxidation, corrosion or other harmful chemical reactions. In the cleaning of the level gauge, the injection of nitrogen helps to remove impurities that may affect the accuracy of the level gauge, while avoiding the use of other gases that may react with liquid ammonia. There are several reasons for choosing nitrogen as an inert gas. First, nitrogen is the gas with the highest content in the atmosphere, accounting for about 78% of the volume of air, so it is abundant in resources and low in cost. Secondly, nitrogen has stable chemical properties, is not easy to burn and does not support combustion, which makes it very safe when used in flammable and explosive environments. In addition, nitrogen is easily available in industry and can be easily produced and purified by equipment such as nitrogen generators. In the application of liquid ammonia level gauges, nitrogen is used to purge the sampling tube 100 during the cleaning process to remove impurities attached to the float sliding rod. Since nitrogen does not react chemically with liquid ammonia, it ensures the safety and effectiveness of the cleaning process. In addition, the temperature and pressure characteristics of nitrogen make it suitable for use in the heating and cleaning process of the liquid level gauge, and can effectively discharge impurities from the sampling tube 100. Therefore, nitrogen is an ideal inert gas choice in the automatic impurity cleaning device of the liquid ammonia liquid level gauge.

[0057] Example 2

[0058] Reference Figure 1-Figure 3 , which is the second embodiment of the present invention. This embodiment is different from the first embodiment in that it is a method for automatically cleaning impurities in a liquid ammonia level meter, which is intended to improve the measurement accuracy and system stability of the liquid ammonia level meter, while ensuring the safety of operation and reducing maintenance costs. The following is a detailed explanation of the method:

[0059] Cut off the connection: In the initial step, the connection between the sampling tube 100 and the liquid ammonia evaporator 900 is cut off by closing the first pneumatic valve 700 and the second pneumatic valve 800. This step is to isolate the liquid level meter during the cleaning process to prevent liquid ammonia leakage or impurities from entering the liquid ammonia evaporator 900.

[0060] Real-time detection and timing: Use the float liquid level sensor 200 to detect the liquid level in real time and start the timing module. The float liquid level sensor 200 monitors the change of the liquid level. If the float is stuck due to impurities, the liquid level feedback reading will remain unchanged or fluctuate within a very small range.

[0061] Data transmission and reception: When the float level sensor 200 identifies signs of the float being stuck, the data is sent to the processor 300. The processor 300 is the control center of the system, receiving signals from the float level sensor 200 and making judgments and decisions according to preset program logic.

[0062] Start heating: After receiving the signal that the float liquid level sensor 200 is stuck, the processor 300 starts the heating pipe 400 to heat the sampling pipe 100. The purpose of heating is to soften or remove impurities attached to the float sliding rod to restore the activity of the float.

[0063] Injection of nitrogen and purging: When the temperature in the sampling tube 100 is heated to above 65° C., nitrogen is injected into the sampling tube 100 through the flow meter 500, and the drain valve 600 is opened. Nitrogen, as an inert gas, is used to purge impurities in the sampling tube 100 to prevent chemical reactions and ensure safety.

[0064] Purging process: Nitrogen purging lasts for 30 seconds to ensure that impurities are effectively removed. This step is the key to the cleaning process to ensure that the measurement accuracy of the level meter is restored.

[0065] Stop heating and close valve: After the purge is completed, stop heating, turn off the flow meter 500 to stop injecting nitrogen, and close the drain valve 600. These operations mark the end of the cleaning process.

[0066] Reconnection: Finally, the first pneumatic valve 700 and the second pneumatic valve 800 are opened to reconnect the sampling tube 100 and the liquid ammonia evaporator 900. This step restores the normal operation of the liquid level meter so that it can continue to monitor the liquid level of liquid ammonia.

[0067] The entire method reduces manual intervention through automated control and improves the safety and efficiency of operations. By automatically cleaning impurities regularly, the failure rate of the level gauge can be significantly reduced, the service life of the equipment can be extended, and production accidents caused by inaccurate level gauges can be reduced. In addition, the method also helps reduce maintenance costs and environmental risks and improves the reliability and stability of the entire liquid ammonia storage and evaporation system.

[0068] The remaining structures are the same as those of Example 1.

[0069] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only several embodiments are described in detail in this disclosure, it should be easily understood by the personnel referring to this disclosure that many modifications are possible (for example, the size, scale, structure, shape and ratio of various elements, and parameter values ​​(for example, temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of a plurality of parts or elements, the position of the element can be inverted or otherwise changed, and the property or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method step can be changed or reordered according to the alternative embodiment. Therefore, the present invention is not limited to a specific embodiment, but extends to a variety of modifications still falling within the scope of the appended claims.

[0070] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0071] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A liquid ammonia level meter with automatic impurity cleaning, characterized in that: The invention comprises a sampling tube (100) and a float liquid level sensor (200) installed inside the sampling tube (100) and used for detecting the position of the float and the liquid level height. The float liquid level sensor (200) transmits the detection data to a processor (300). A heating pipe (400) is arranged on the outer wall of the sampling tube (100). A flow meter (500) for introducing an inert gas is arranged at the upper end of the sampling tube (100). A drain valve (600) is arranged at the lower end of the sampling tube (100).

2. A liquid ammonia level gauge with automatic impurity cleaning according to claim 1, characterized in that: The outer wall of the sampling tube (100) is provided with a first pneumatic valve (700) at the upper end, and a second pneumatic valve (800) at the lower end; the first pneumatic valve (700) and the second pneumatic valve (800) are both connected to the liquid ammonia evaporator (900).

3. A liquid ammonia level gauge with automatic impurity cleaning according to claim 2, characterized in that: A sliding rod is arranged inside the sampling tube (100), and a hole is arranged at the center of the float liquid level sensor (200). The float liquid level sensor (200) passes through the hole and performs limiting lifting and lowering movement along the sliding rod.

4. A liquid ammonia level gauge with automatic impurity cleaning according to claim 3, characterized in that: The processor (300) is connected to the float liquid level sensor (200), the flow meter (500), the drain valve (600), the heating pipe (400), the first pneumatic valve (700), and the second pneumatic valve (800).

5. A liquid ammonia level gauge with automatic impurity cleaning according to claim 4, characterized in that: The processor (300) and the single-chip microcomputer are main controllers, which are used to receive signals from the float liquid level sensor (200) and control the flow meter (500), the drain valve (600), the heating pipe (400), the first pneumatic valve (700) and the second pneumatic valve (800) to execute. It includes a communication module for remote monitoring and control, and can integrate a wireless communication module (such as Wi-Fi, Bluetooth, 4G, etc.) for the transmission of data and control fingers; The analog-to-digital conversion module converts the analog signal into a digital signal; The timing module is used to time the duration of the state where the liquid level does not change; The logic judgment module determines that the level meter is stuck when the liquid level reading fluctuates within a set very small range or remains unchanged for more than 120 seconds; The display module is used for human-computer interaction, showing the current liquid level and status, and issuing an audible and visual alarm when the liquid level gauge is detected to be stuck.

6. The liquid ammonia level gauge with automatic impurity cleaning according to claim 1, characterized in that: The heating pipe (400) is wrapped around the outer wall of the sampling tube (100) and has a built-in heating wire.

7. A liquid ammonia level gauge with automatic impurity cleaning according to claim 6, characterized in that: The flow meter (500) is used to control the time for the inert gas to be introduced, and the inert gas is nitrogen.

8. A method for automatically cleaning impurities in a liquid ammonia level gauge, characterized in that: A liquid ammonia level meter with automatic impurity cleaning comprising any one of claims 1 to 7, and Closing the first pneumatic valve (700) and the second pneumatic valve (800) to cut off the connection between the sampling tube (100) and the liquid ammonia evaporator (900); The float liquid level sensor (200) detects the liquid level in real time and performs timing. When the float is stuck, the liquid level feedback reading remains unchanged or fluctuates within a very small range, and the float liquid level sensor (200) sends data to the processor (300); After receiving the information, the processor (300) starts the heating pipe (400) to heat the sampling pipe (100); When the temperature reaches a preset value, nitrogen is injected into the sampling tube (100) through the flow meter (500), and the drain valve (600) is opened; Stop heating, turn off the flow meter (500), stop injecting nitrogen, close the drain valve (600), open the first pneumatic valve (700) and the second pneumatic valve (800), and reconnect the sampling tube (100) and the liquid ammonia evaporator (900).

9. The method for automatically cleaning impurities of a liquid ammonia level gauge according to claim 8, characterized in that: Heat the inside of the sleeve to above 65°C before cleaning.

10. The method for automatically cleaning impurities of a liquid ammonia level gauge according to claim 8, characterized in that: After the temperature is met, inert gas is introduced and the drain valve (600) is opened simultaneously, and the purge is continued for 30 seconds.

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