Closed liquid level measuring instrument

Abstract

The utility model discloses a closed type liquid level measuring instrument which comprises a main shell, an ultrasonic sensor, a connecting assembly and a display assembly, the display assembly is connected with the main shell and used for displaying liquid data, the display assembly is electrically connected with the ultrasonic sensor, and the connecting assembly is arranged in the main shell and can stretch out and retract back. The connecting assembly is used for connecting the display assembly and the ultrasonic sensor. During use, an operator controls the connecting assembly to stretch out, the connecting assembly drives the ultrasonic sensor to enter the storage tank, when the ultrasonic sensor makes contact with the liquid level, a liquid level electric signal is sent to the display assembly, data are transmitted, and the display assembly displays the liquid data so that the operator can read the liquid data. An operator does not need to manually judge the liquid level position, so that the automation of data reading of the liquid in the storage tank is realized, and the accuracy of liquid level measurement is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of storage tank liquid level measurement equipment, in particular to a closed liquid level measuring instrument. Background Art

[0002] At present, petrochemical storage enterprises are gradually carrying out pressurized closed nitrogen sealing of storage tanks. In the current measurement method, the reading of the liquid level and water level depends on reading the mark left by the liquid on the scale to obtain the position of the liquid level inside the storage tank. Since it is perceived by humans, it will cause a large human error. In this context, the method of using a dipstick to measure the liquid level, water level, and temperature inside the storage tank is no longer applicable.

[0003] Therefore, how to improve the accuracy of liquid level measurement is a technical problem that those skilled in the art need to solve at present. Content of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a closed liquid level measuring instrument to improve the accuracy of liquid level measurement;

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A closed liquid level measuring instrument includes a main housing, an ultrasonic sensor, a connection component, and a display component, wherein:

[0007] The display component is connected to the main housing for displaying liquid data, and the display component is electrically connected to the ultrasonic sensor;

[0008] The connection component is arranged inside the main housing, and the connection component can extend and retract. The connection component is used to connect the display component and the ultrasonic sensor.

[0009] Optionally, in the above closed liquid level measuring instrument, the connection component includes a steel tape cable, a crank, a pull rod, and a tape, wherein:

[0010] The crank is fixedly connected to the first end of the pull rod;

[0011] The second end of the pull rod is sequentially connected to the tape and the steel tape cable;

[0012] When the crank rotates in the first direction, the pull rod drives the tape to wind in the first direction, and the tape drives the steel tape cable to move upward;

[0013] When the crank rotates in the second direction, the pull rod drives the tape to wind in the second direction, and the tape drives the steel tape cable to move downward.

[0014] Optionally, in the above-mentioned closed-type liquid level measuring instrument, the ultrasonic sensor includes a probe, a first fork body and a second fork body. The first fork body is the transmitting end, and the second fork body is the receiving end. When the probe enters the liquid, the space between the first fork body and the second fork body is filled with liquid, and the ultrasonic sensor sends the liquid temperature signal and the liquid level signal to the display component.

[0015] Optionally, in the above-mentioned closed-type liquid level measuring instrument, the display component includes a reading window, which is fixed on the outer surface of the main housing and is used to display the current scale of the steel tape cable.

[0016] Optionally, in the above-mentioned closed-type liquid level measuring instrument, the display component further includes an instrument housing, a display screen and a buzzer. The instrument housing is fixed on the outer surface of the main housing, the display screen and the buzzer are connected to the instrument housing. The display screen is used to display the liquid temperature, and the buzzer is used to emit a warning sound for liquid data.

[0017] Optionally, in the above-mentioned closed-type liquid level measuring instrument, the closed-type liquid level measuring instrument further includes a cleaning component, which includes a knob, a first oil scraping shaft and a second oil scraping shaft, where:

[0018] The knob is connected to the main housing and is arranged on the outer surface of the main housing;

[0019] The first oil scraping shaft and the second oil scraping shaft are arranged oppositely, and the first oil scraping shaft and the second oil scraping shaft are connected to the knob;

[0020] When the knob rotates in the first direction, the first oil scraping shaft and the second oil scraping shaft approach each other, and a gap for the steel tape cable to move upward is formed between the first oil scraping shaft and the second oil scraping shaft.

[0021] Optionally, in the above-mentioned closed-type liquid level measuring instrument, the display component further includes a window cleaner, where:

[0022] The window cleaner includes a telescopic rod and a scraper;

[0023] The telescopic rod is connected to the scraper, and the scraper is matched with the window of the reading window;

[0024] When the telescopic rod is in the extended state, the scraper extends and scrapes across the window;

[0025] When the telescopic rod is in the retracted state, the scraper retracts and scrapes across the window.

[0026] Optionally, in the above-mentioned closed-type liquid level measuring instrument, the closed-type liquid level measuring instrument further includes a sensor storage barrel and a quick connector, where:

[0027] The first end of the sensor storage barrel is connected to the main housing, and its second end is connected to the quick connector;

[0028] The quick connector is detachably connected to the storage tank;

[0029] A steel tape cable and an ultrasonic sensor are arranged inside the sensor storage barrel;

[0030] When the steel tape cable is in the downward state, the ultrasonic sensor passes through the quick connector.

[0031] Optionally, in the above-mentioned closed - type liquid level measuring instrument, the closed - type liquid level measuring instrument further includes a grounding clip, which is connected to the main housing and is used for clamping the storage tank to conduct the static electricity of the closed - type liquid level measuring instrument.

[0032] Optionally, in the above - mentioned closed - type liquid level measuring instrument, the closed - type liquid level measuring instrument further includes a handle, which is connected to the main housing.

[0033] When the closed - type liquid level measuring instrument provided by the present utility model is in use, an operator controls the connecting component to extend, and the connecting component drives the ultrasonic sensor to enter the interior of the storage tank. When the ultrasonic sensor contacts the liquid surface, it sends a liquid - surface electrical signal to the display component and transmits data. The display component displays the liquid data for the operator to read. By arranging the ultrasonic sensor, the operator does not need to judge the liquid - surface position manually, thereby realizing the automation of reading the internal liquid data of the storage tank and improving the accuracy of liquid - level measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following - described drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0035] Figure 1 It is a schematic diagram of the overall structure of the closed - type liquid level measuring instrument disclosed in the embodiment of the present utility model;

[0036] Figure 2 It is a schematic diagram of the structure of the ultrasonic sensor and the steel tape cable disclosed in the embodiment of the present utility model;

[0037] Figure 3 It is a schematic diagram of the structure of the cleaning component disclosed in the embodiment of the present utility model;

[0038] Figure 4 It is a top view of the cleaning component disclosed in the embodiment of the present utility model;

[0039] Figure 5 It is an enlarged view of the partial structure of the closed - type liquid level measuring instrument disclosed in the embodiment of the present utility model;

[0040] Figure 6Schematic structural diagram of the window cleaner disclosed in the embodiments of the present utility model;

[0041] Wherein:

[0042] 1 - ultrasonic sensor, 2 - steel tape cable, 3 - crank, 4 - instrument housing, 5 - display screen, 6 - buzzer, 7 - main housing, 8 - handle, 9 - window cleaner, 10 - reading window, 11 - cleaning assembly, 12 - grounding clip, 13 - sensor storage cylinder, 14 - quick connector;

[0043] 20 - knob, 21 - linkage, 22 - rotating block, 23 - oil scraping base, 24 - first oil scraping shaft, 25 - oil scraping rubber strip, 26 - telescopic rod, 27 - scraper, 28 - cleaner body, 30 - pull rod. Specific embodiments

[0044] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present utility model.

[0045] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top surface", "bottom surface", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the indicated position or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0046] As Figures 1 - 6 shown, the closed - type liquid level measuring instrument disclosed by the present utility model includes a main housing 7, an ultrasonic sensor 1, a connection assembly, and a display assembly. Among them, the display assembly is connected to the main housing 7 and is used to display liquid data. The display assembly is electrically connected to the ultrasonic sensor 1. The connection assembly is arranged inside the main housing 7 and can extend and retract. The connection assembly is used to connect the display assembly and the ultrasonic sensor 1. Specifically, the closed - type liquid level measuring instrument is mainly used to measure the temperature, liquid level, water level, and the overall height of the storage tank inside the closed storage tank and oil tanker. The above - mentioned liquid data includes water level, liquid level, and temperature.

[0047] The enclosed liquid level measuring instrument provided by the utility model, when in use, the operator controls the connecting component to extend, and the connecting component drives the ultrasonic sensor 1 into the interior of the storage tank. When the ultrasonic sensor 1 touches the liquid level, it sends a liquid level electrical signal to the display component and transmits data. The display component displays the liquid data for the operator to read. By arranging the ultrasonic sensor 1, the operator does not need to manually judge the liquid level position, thus realizing the automation of reading the internal liquid data of the storage tank and improving the accuracy of liquid level measurement.

[0048] To optimize the above technical solution, the connecting component includes a steel tape cable 2, a crank 3, a pull rod 30 and a tape. Among them, the crank 3 is fixedly connected to the first end of the pull rod 30. The second end of the pull rod 30 is sequentially connected to the tape and the steel tape cable 2. When the crank 3 rotates in the first direction, the pull rod 30 drives the tape to wind in the first direction, and the tape drives the steel tape cable 2 to move upward. When the crank 3 rotates in the second direction, the pull rod 30 drives the tape to wind in the second direction, and the tape drives the steel tape cable 2 to move downward. Specifically, the crank 3 can be manually controlled and can stay at the required position at any time. The tape is wound inside the winding disc, and the pull rod 30 is connected to the winding disc. When the crank 3 rotates, the winding disc rotates synchronously, so that the tape extends out or retracts into the winding disc, thereby driving the steel tape cable 2 to move upward or downward. The above first direction is one of clockwise or counterclockwise, and the second direction is the other of clockwise or counterclockwise.

[0049] When in use, the operator controls the downward length of the steel tape cable 2 through the crank 3, that is, the vertical position of the ultrasonic sensor 1 inside the storage tank. When the ultrasonic sensor 1 touches the liquid level or reaches other preset positions, stop operating the crank 3 and record the data. Such an arrangement can realize the fixed-point movement of the ultrasonic sensor 1, avoiding the measurement error caused by manually sending the measuring tape in the prior art, thereby improving the accuracy of liquid level measurement.

[0050] To optimize the above technical solution, the ultrasonic sensor 1 includes a probe, a first fork body and a second fork body. The first fork body is the transmitting end, and the second fork body is the receiving end. When the probe enters the liquid, the space between the first fork body and the second fork body is filled with liquid, and the ultrasonic sensor 1 sends a liquid temperature signal and a liquid level signal to the display component. Specifically, the ultrasonic sensor can send a signal to the display component when it touches the liquid level, prompting the operator that the ultrasonic sensor has reached the liquid level position. When there is water inside the storage tank and the ultrasonic sensor reaches the oil-water interface, the ultrasonic sensor will send a different signal to the display component from when it touches the oil liquid. At the same time, when the ultrasonic sensor is in the liquid, it will send a liquid temperature signal to the display component, and the display component will display the current real-time temperature.

[0051] Specifically, the temperature accuracy of the liquid temperature signal sent by the ultrasonic sensor can reach ±0.1°C of the actual value, and the interface detection accuracy of the liquid level signal sent by the ultrasonic sensor can reach ±2 mm of the actual value. When in use, the liquid level measurement of the ultrasonic sensor 1 uses the ultrasonic principle. With two groups of piezoelectric ceramics as the ultrasonic source, there is a transmitting end and a receiving end, which are respectively placed in the first fork body and the second fork body. When the probe of the ultrasonic sensor 1 enters the liquid, the liquid will fill the gap between the first fork body and the second fork body. Because the propagation speed of ultrasonic waves changes significantly in air and liquid, the accurate position of the liquid level can be sensed and a liquid level signal can be given. The principle of water level measurement is to use the change in the resistance of the water measuring probe to detect the water level and give a liquid level signal. The principle of temperature measurement is to use the change in platinum resistance to measure the liquid temperature and give a liquid temperature signal.

[0052] Such an arrangement enables the operator to measure the liquid level height, water level height, and liquid temperature without carrying multiple measuring instruments, achieving multi-function in one machine, improving the measurement efficiency, avoiding data errors caused by manual measurement, and thus improving the accuracy of liquid level measurement.

[0053] To optimize the above technical solution, the display component includes a reading window 10, and the reading window 10 is fixed on the outer surface of the main housing 7. The reading window 10 is used to display the current scale of the steel tape cable 2. Specifically, the reading window 10 is arranged on the moving path of the steel tape cable 2, and the operator can read the current scale of the steel tape cable 2 through the reading window 10.

[0054] When in use, when the ultrasonic sensor 1 reaches the preset position and sends a liquid temperature signal and a liquid level signal to the display component, the operator reads and records the scale value of the current steel tape cable 2 through the reading window 10 to achieve liquid temperature monitoring. Such an arrangement realizes the automatic monitoring of the liquid temperature and further improves the accuracy of liquid temperature measurement.

[0055] To optimize the above technical solution, the display component further includes an instrument housing 4, a display screen 5, and a buzzer 6. The instrument housing 4 is fixed on the outer surface of the main housing 7. The display screen 5 and the buzzer 6 are connected to the instrument housing 4. The display screen 5 is used to display the liquid temperature, and the buzzer 6 is used to emit a warning sound for liquid data. Specifically, when the ultrasonic sensor contacts the liquid surface, it sends a signal to the display component, and the buzzer 6 emits a warning sound for liquid data to prompt the operator that the ultrasonic sensor has reached the liquid surface position. When the ultrasonic sensor reaches the oil-water interface, the ultrasonic sensor will send a different signal to the display component from when it contacts the oil, and the buzzer 6 emits a warning sound for liquid data with a different tone from the above. When the ultrasonic sensor is in the liquid, it will send a liquid temperature signal to the display component, and the display screen 5 displays the current real-time temperature.

[0056] To optimize the above technical solution, the closed - type liquid level measuring instrument further includes a cleaning assembly 11. The cleaning assembly 11 includes a knob 20, a first oil - scraping shaft 24 and a second oil - scraping shaft. Among them, the knob 20 is connected to the main housing 7 and is arranged on the outer surface of the main housing 7. The first oil - scraping shaft 24 and the second oil - scraping shaft are arranged oppositely, and the first oil - scraping shaft 24 and the second oil - scraping shaft are connected to the knob 20. When the knob 20 rotates in the first direction, the first oil - scraping shaft 24 and the second oil - scraping shaft approach each other, and a gap for the steel tape cable 2 to move upward is formed between the first oil - scraping shaft 24 and the second oil - scraping shaft. It should be noted that in the current measurement method, a large amount of oil stains and chemical liquids will adhere during the measurement process, which requires manual cleaning and is rather inconvenient.

[0057] Specifically, oil - scraping rubber strips 25 are arranged on both the first oil - scraping shaft 24 and the second oil - scraping shaft. The oil - scraping rubber strips 25 are used to clamp the tape to achieve the function of scraping oil. Specifically, the cleaning assembly 11 is an eccentric rotation mechanism. In addition to the knob 20, the first oil - scraping shaft 24 and the second oil - scraping shaft, it further includes a linkage 21, a rotating block 22 and an oil - scraping base 23. The knob 20 is connected to the linkage 21 through a shaft, the rotating block 22 is connected to the first oil - scraping shaft 24 and the second oil - scraping shaft, and the oil - scraping base 23 plays a supporting role.

[0058] During use, the operator rotates the knob 20, and the shaft drives the first oil - scraping shaft 24 and the second oil - scraping shaft to rotate eccentrically through the linkage 21 and the rotating block 22, so that the gap between the first oil - scraping shaft 24 and the second oil - scraping shaft becomes larger or smaller. When the steel tape cable 2 passes through this gap, the first oil - scraping shaft 24, the second oil - scraping shaft and the oil - scraping rubber strips 25 on both sides of it perform the oil - scraping operation. When the knob 20 is tightened, the ultrasonic sensor 1 can be clamped to prevent it from falling and being damaged. Such an arrangement can scrape off the grease or chemicals attached to the steel tape cable 2 and prevent them from entering the main housing 7, thereby extending the service life of the closed - type liquid level measuring instrument.

[0059] To optimize the above technical solution, the display assembly further includes a window cleaner 9. Among them, the window cleaner 9 includes a telescopic rod 26 and a scraper 27. The telescopic rod 26 is connected to the scraper 27, and the scraper 27 is matched with the window of the reading window 10. When the telescopic rod 26 is in the extended state, the scraper 27 extends and scrapes across the window. When the telescopic rod 26 is in the retracted state, the scraper 27 retracts and scrapes across the window. Specifically, the window cleaner 9 further includes a cleaner body 28. The reading window 10 is the window of the cleaner body 28. One side of the scraper 27 abuts against the inner surface of the cleaner body 28, that is, the inner surface of the reading window 10. The operator can control the telescopic rod 26 to extend and retract by manual pulling to repeatedly clean the reading window 10.

[0060] Initially, the telescopic rod 26 is in a retracted state. When there is water mist left on the reading window 10, or in other situations where the reading window 10 needs to be cleaned, the operator controls the telescopic rod 26 to extend. The scraper 27 extends and scrapes across the window. Subsequently, the operator controls the telescopic rod 26 to retract, and the scraper 27 retracts and scrapes across the window. This operation is repeated until the reading window 10 can clearly reflect the data. Such an arrangement can achieve the cleaning of the window of the reading window 10, facilitating the operator to read the data, thereby improving the working efficiency of the operator in recording the liquid temperature and liquid level data.

[0061] To optimize the above technical solution, the closed - type liquid level measuring instrument further includes a sensor storage barrel 13 and a quick - connector 14. Among them, the first end of the sensor storage barrel 13 is connected to the main housing 7, and its second end is connected to the quick - connector 14. The quick - connector 14 is detachably connected to the storage tank. The steel tape cable 2 and the ultrasonic sensor 1 are arranged inside the sensor storage barrel 13. When the steel tape cable 2 is in the downward state, the ultrasonic sensor 1 passes through the quick - connector 14. It should be noted that the current measurement method requires opening the lid of the storage tank for measurement, which will not only cause nitrogen leakage, increase the enterprise cost, but also pose a great safety hazard to the operator. The quick - connector 14 provided by the present utility model is used to integrally install the closed - type liquid level measuring instrument on the steam lock valve of the storage tank, thereby ensuring the stability of the closed - type liquid level measuring instrument. After the quick - connector 14 is connected, the closed - type liquid level measuring instrument and the tank body of the storage tank form a closed cavity, so that when the closed - type liquid level measuring instrument is in the working state, the sealing performance of the storage tank is ensured.

[0062] During use, after the measurement is completed, the operator controls the steel tape cable 2 to move upward, and the cleaning component 11 cleans it until the ultrasonic sensor 1 is received into the sensor storage barrel 13, and then the operator removes the quick - connector 14. Specifically, the sensor storage barrel 13 is used to limit and protect the steel tape cable 2 and the ultrasonic sensor 1. Such an arrangement can achieve closed - type measurement, effectively prevent the leakage of harmful gases, and avoid the danger to the operator during the measurement of the liquid level and water level in the nitrogen - sealed pressure tank, realizing accurate and efficient measurement. Moreover, the maximum pressure resistance of the closed - type liquid level measuring instrument can reach 0.3 bar, with relatively high safety.

[0063] To optimize the above technical solution, the closed - type liquid level measuring instrument further includes a grounding clip 12. The grounding clip 12 is connected to the main housing 7 and is used to clamp the storage tank to conduct the static electricity of the closed - type liquid level measuring instrument. By arranging the grounding clip 12, the static electricity of the closed - type liquid level measuring instrument can be conducted to ensure the safety during the use of the closed - type liquid level measuring instrument.

[0064] Furthermore, a layer of anti - corrosion material covers both the inside and outside of the main housing 7 to prevent corrosion caused by oil stains and chemicals entering the main housing 7.

[0065] To optimize the above technical solution, the closed - type liquid level measuring instrument further includes a handle 8, and the handle 8 is connected to the main housing 7. Specifically, the handle 8 is used for an operator to hold the closed - type liquid level measuring instrument, so as to improve the convenience of using the closed - type liquid level measuring instrument.

[0066] The advantages of the present utility model are as follows:

[0067] (1) The accuracy of liquid level measurement is improved;

[0068] (2) The accuracy of liquid temperature measurement is improved;

[0069] (3) Closed - type measurement is realized, and the safety is high.

[0070] It should be noted that the closed - type liquid level measuring instrument provided by the present utility model can be used in the technical field of storage tank liquid level measuring equipment or other fields. The other fields refer to any fields other than the technical field of storage tank liquid level measuring equipment. The above is only an example, and it does not limit the application field of the closed - type liquid level measuring instrument provided by the present utility model.

[0071] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0072] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0073] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0074] The preferred embodiments of the present utility model disclosed above are only used to help illustrate the present utility model. The preferred embodiments do not describe all the details in detail, nor do they limit the present utility model to only the specific implementation manners. Obviously, many modifications and variations can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principle and practical application of the present utility model, so that those skilled in the relevant technical field can well understand and utilize the present utility model. The present utility model is only limited by the claims and their full scope and equivalents.

Claims

1. A closed liquid level measuring instrument, characterized in that: It includes a main housing, an ultrasonic sensor, a connection component and a display component, wherein: The display assembly is connected to the main housing and is used to display liquid data, and the display assembly is electrically connected to the ultrasonic sensor; The connecting component is arranged inside the main shell and can be extended and retracted. The connecting component is used to connect the display component and the ultrasonic sensor.

2. The closed liquid level measuring instrument according to claim 1, characterized in that: The connecting assembly comprises a steel ruler cable, a crank handle, a pull rod and a ruler tape, wherein: The crank handle is fixedly connected to the first end of the pull rod; The second end of the pull rod is connected to the ruler tape and the steel ruler cable in sequence; When the crank rotates in a first direction, the pull rod drives the ruler tape to wind in the first direction, and the ruler tape drives the steel ruler cable upward; When the crank handle rotates in the second direction, the pull rod drives the ruler tape to wind in the second direction, and the ruler tape drives the steel ruler cable downward.

3. The closed liquid level measuring instrument according to claim 1, characterized in that: The ultrasonic sensor includes a probe, a first fork body and a second fork body, the first fork body is a transmitting end, and the second fork body is a receiving end. When the probe enters the liquid, the space between the first fork body and the second fork body is filled with liquid, and the ultrasonic sensor sends a liquid temperature signal and a liquid level signal to the display component.

4. The closed liquid level measuring instrument according to claim 2, characterized in that: The display component comprises a reading window, which is fixed to the outer surface of the main housing and is used to display the current scale of the steel ruler cable.

5. The closed liquid level measuring instrument according to claim 1, characterized in that: The display assembly also includes an instrument case, a display screen and a buzzer. The instrument case is fixed to the outer surface of the main housing. The display screen and the buzzer are connected to the instrument case. The display screen is used to display the liquid temperature, and the buzzer is used to emit a liquid data warning sound.

6. The closed liquid level measuring instrument according to claim 2, characterized in that: The enclosed liquid level measuring instrument further comprises a cleaning assembly, wherein the cleaning assembly comprises a knob, a first scraper shaft and a second scraper shaft, wherein: The knob is connected to the main housing and arranged on the outer surface of the main housing; The first oil scraping shaft and the second oil scraping shaft are arranged opposite to each other, and the first oil scraping shaft and the second oil scraping shaft are connected to the knob; When the knob is rotated in a first direction, the first oil scraping shaft and the second oil scraping shaft approach each other, and a gap is formed between the first oil scraping shaft and the second oil scraping shaft for the steel ruler cable to move upward.

7. The closed liquid level measuring instrument according to claim 4, characterized in that: The display assembly also includes a window cleaner, wherein: The window cleaner comprises a telescopic rod and a scraper; The telescopic rod is connected to the scraper, and the scraper matches the window of the reading window; When the telescopic rod is in an extended state, the scraper extends and scrapes across the window; When the telescopic rod is in the retracted state, the scraper is retracted and scrapes across the window.

8. The closed liquid level measuring instrument according to claim 2, characterized in that: The enclosed liquid level measuring instrument also includes a sensor storage barrel and a quick connector, wherein: The first end of the sensor storage barrel is connected to the main housing, and the second end thereof is connected to the quick connector; The quick connector is detachably connected to the storage tank; The steel ruler cable and the ultrasonic sensor are arranged inside the sensor storage barrel; When the steel ruler cable is in a downward state, the ultrasonic sensor passes through the quick connector.

9. The closed liquid level measuring instrument according to any one of claims 1 to 8, characterized in that: The enclosed liquid level measuring instrument further comprises a grounding clamp, which is connected to the main housing and is used for clamping the storage tank to conduct static electricity of the enclosed liquid level measuring instrument.

10. The closed liquid level measuring instrument according to any one of claims 1 to 8, characterized in that: The enclosed liquid level measuring instrument further comprises a handle, and the handle is connected to the main housing.

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