Double-insurance liquid nitrogen liquid level detection device

Abstract

The utility model provides a double-insurance liquid nitrogen liquid level detection device, and belongs to the field of monitoring equipment of an assisted reproduction laboratory. Comprising an upper cover body, a thermal insulation material column, a liquid level sensor, a temperature sensor and an electric control mainboard. The electric control mainboard is installed on one side face of the upper cover body, the heat preservation material column is connected to the other side face of the upper cover body, a positioning connecting piece is arranged at the end, away from the upper cover body, of the heat preservation material column, and the liquid level sensor and the temperature sensor are arranged in parallel, embedded in the positioning connecting piece and electrically connected with the electric control mainboard. The electronic control mainboard is provided with a display panel used for displaying detection values of the liquid level sensor and the temperature sensor, and the display panel is configured to send alarm information when the detection values are abnormal. The technical problems of difficulty in real-time detection of the liquid level in the liquid nitrogen tank and low detection accuracy caused by structure and detection accuracy defects of a traditional detection mode in the related technology can be solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the auxiliary reproductive laboratory monitoring equipment field, especially in kind of double insurance liquid nitrogen liquid level detection device. BACKGROUND

[0002] Liquid nitrogen is the product that nitrogen gas is liquefied under high pressure and extremely low temperature, can produce lower temperature, and has the characteristics of non-toxic, colorless, odorless, not flammable and explosive and chemical stability, in recent years, is widely used in reproductive scientific research projects as the freezing preservation means of biological samples such as embryos. Because the container for storing liquid nitrogen is special, it is usually stored in a liquid nitrogen tank, and it is difficult to observe the remaining liquid nitrogen level in the container from the outside with the naked eye, so that the liquid nitrogen cannot be replenished in time during the use of liquid nitrogen, and the biological samples stored inside are damaged.

[0003] In the related art, the liquid level detection technology of liquid nitrogen mainly includes: pressure sensor detection method, ultrasonic sensor detection method, infrared laser detection method, capacitive detection method, float detection method and thermocouple temperature detection method. Among them, the pressure sensor detection method is strict in the sealing requirement of the tank body; the ultrasonic sensor and the infrared laser detection require the opening of the liquid nitrogen tank, which is not suitable for real-time liquid level detection during the storage of the liquid nitrogen tank; the float detection method has low precision; the thermocouple sensor detection method detects the liquid level by the temperature rise when the liquid level is lower than the sensor, but this method can only detect whether the liquid level is lower than a specific position, and cannot accurately measure the liquid level height; the capacitive sensor needs to place the two levels of the capacitor in the liquid nitrogen tank, and the change of the liquid level causes the change of the capacitance, but this method requires professional installation technology, and the error caused by the installation gap will affect the final accuracy. The above detection methods all have defects in detection accuracy and installation difficulty, and are not suitable for the real-time and accurate monitoring of the liquid level in the tank in the auxiliary reproductive laboratory, which frequently uses liquid nitrogen for sample preservation. And the sensor is a precision device, even if it is accurately set in the liquid nitrogen tank, if it is damaged and fails to detect, it will also bring uncertainty to the sample preservation in the auxiliary reproductive laboratory, causing the loss of valuable biological samples. UTILITY MODEL CONTENTS

[0004] The utility model embodiment provides a kind of double insurance liquid nitrogen liquid level detection device, can solve the technical problem that the real-time detection of liquid level in liquid nitrogen tank is difficult and detection accuracy is low in traditional detection method in the related art due to structural and detection precision defects. The technical solution is as follows:

[0005] The utility model embodiment provides a kind of double insurance liquid nitrogen liquid level detection device, including upper cover body, heat preservation material column, liquid level sensor, temperature sensor and electric control mainboard,

[0006] The electric control mainboard is installed on the upper cover body, the heat preservation material column is connected to one side of the upper cover body, one end of the heat preservation material column away from the upper cover body is provided with a positioning connecting piece, the liquid level sensor and the temperature sensor are arranged side by side and embeddedly installed on the positioning connecting piece, the liquid level sensor and the temperature sensor are electrically connected with the electric control mainboard, a display panel for displaying detection values of the liquid level sensor and the temperature sensor is arranged on the electric control mainboard, and the display panel is configured to send an alarm information when the detection values are abnormal.

[0007] Optionally, first and second assembly holes are arranged on a side end face of the positioning connecting piece away from the heat preservation material column, the top of the liquid level sensor is embeddedly installed in the first assembly hole, and the top of the temperature sensor is embeddedly installed in the second assembly hole.

[0008] Optionally, the liquid level sensor is a cylindrical capacitive liquid level sensor, a first screw fixing hole is arranged on a side wall of an embedded end of the liquid level sensor, and a second screw fixing hole matched with the first screw fixing hole is arranged on the positioning connecting piece.

[0009] Optionally, a cylindrical inner positioning sleeve is sleeved on the liquid level sensor, an outer diameter of the inner positioning sleeve is greater than an outer diameter of an embedded end of the liquid level sensor and is matched with an inner diameter of the first assembly hole, and a third screw fixing hole matched with the first and second screw fixing holes is arranged on a side wall of the inner positioning sleeve.

[0010] Optionally, the double-insurance liquid nitrogen liquid level detection device further comprises a temperature sensor positioning pipe, one end of the temperature sensor positioning pipe is embeddedly installed in the second assembly hole, a detection through hole is arranged on a side wall of the other end of the temperature sensor positioning pipe and the other end is closed, and the temperature sensor is arranged in the temperature sensor positioning pipe and a probe end is located in the other end of the temperature sensor positioning pipe.

[0011] Optionally, a probe protection pipe is coaxially sleeved on the other end of the temperature sensor positioning pipe, and the detection through hole is arranged on a side wall of the probe protection pipe.

[0012] Optionally, the probe protection pipe and the temperature sensor positioning pipe are detachably connected.

[0013] Optionally, an inner thread hole is arranged on an end face of one end of the heat preservation material column away from the upper cover body, an outer thread column is arranged on the top of the positioning connecting piece, and the outer thread column is threadedly connected with the inner thread hole.

[0014] Optionally, the double insurance liquid nitrogen liquid level detection device further comprises a battery box, an end surface of the heat preservation material column connected with the upper cover body is provided with a battery box mounting hole, and the battery box is arranged in the battery box mounting hole and electrically connected with the electric control mainboard.

[0015] Optionally, the heat preservation material column is a foam plug column.

[0016] The technical scheme provided by the embodiment of the utility model brings at least the following beneficial effects:

[0017] The double insurance liquid nitrogen liquid level detection device provided by the embodiment of the utility model is integrated with the cover body of the traditional liquid nitrogen tank, the heat preservation material column for sealing and temperature insulation is installed on the inner side surface of the upper cover body, the liquid level sensor and the temperature sensor as detection elements are integrated into the bottom of the heat preservation material column through the positioning connecting piece as the fixed transfer, the problem that the two sensors are not easy to install is solved, the installation position of the sensor is fixed and there is no obvious gap. After the corresponding installation of the upper cover body and the corresponding liquid nitrogen tank is completed, the liquid level sensor and the temperature sensor can feed back the liquid level data and the temperature data in the tank to the electric control mainboard in real time, and the display panel is used for checking and confirming by the staff, the opening of the liquid nitrogen tank is not needed, the use of the liquid nitrogen tank is not affected, and the accelerated liquid nitrogen is avoided.

[0018] Meanwhile, through the additional temperature sensor, the double insurance confirmation in the detection process is realized by using the comparative change relationship between the internal temperature and the liquid nitrogen liquid level, when the detection data of the liquid level sensor is abnormal compared with the data of the temperature sensor, the electric control mainboard can timely send an alarm information to the outside, reminding the staff to timely confirm and check the equipment. The technical problem that the real-time detection of the liquid level in the liquid nitrogen tank is difficult and the detection accuracy is low due to the structural and detection precision defects of the traditional detection method in the related art is effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the drawings needed to be used in the embodiment description will be briefly introduced as follows, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by the drawings for the ordinary skilled in the art without creating labor.

[0020] Figure 1 is the three-dimensional structure schematic diagram of the double insurance liquid nitrogen liquid level detection device provided by the embodiment of the utility model;

[0021] Figure 2 is the structure explosion schematic diagram of the double insurance liquid nitrogen liquid level detection device provided by the embodiment of the utility model;

[0022] Figure 3 is a structure sectional view of the double insurance liquid nitrogen liquid level detection device provided by the embodiment of the present application.

[0023] In the figure: 1 - upper cover body; 2 - heat preservation material column; 3 - liquid level sensor; 4 - temperature sensor; 5 - electric control mainboard; 6 - positioning connecting piece; 6a - first column; 6b - second column; 7 - temperature sensor positioning pipe; 8 - battery box; 9 - sealing ring; 21 - wire hole; 22 - internal thread hole; 23 - battery box mounting hole; 31 - first screw fixing hole; 32 - internal positioning sleeve; 51 - display panel; 61 - first assembly hole; 62 - second assembly hole; 63 - second screw fixing hole; 64 - external thread column; 71 - detection through hole; 72 - probe protection pipe; 321 - third screw fixing hole. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application more clear, the following will combine the drawings to make further detailed description on the embodiment of the present application.

[0025] Figure 1 is a three-dimensional structure schematic diagram of the double insurance liquid nitrogen liquid level detection device provided by the embodiment of the present application; Figure 2 is a structure explosion schematic diagram of the double insurance liquid nitrogen liquid level detection device provided by the embodiment of the present application; Figure 3 is a structure sectional view of the double insurance liquid nitrogen liquid level detection device provided by the embodiment of the present application. As Figures 1 to 3 indicated, the embodiment of the present application provides a double insurance liquid nitrogen liquid level detection device, which comprises an upper cover body 1, a heat preservation material column 2, a liquid level sensor 3, a temperature sensor 4 and an electric control mainboard 5.

[0026] Among them, the electric control mainboard 5 is installed inside the upper cover body 1, the display panel with control buttons and display screen is exposed to one side surface of the upper cover body 1, the heat preservation material column 2 is connected to the other side surface opposite to the upper cover body 1, the heat preservation material column 2 is provided with a positioning connecting piece 6 at one end away from the upper cover body 1, and the liquid level sensor 3 and the temperature sensor 4 are arranged side by side and embeddedly installed on the positioning connecting piece 6. The liquid level sensor 3 and the temperature sensor 4 are electrically connected with the electric control mainboard 5, the display panel 51 for displaying the detection values of the liquid level sensor 3 and the temperature sensor 4 is arranged on the electric control mainboard 5, and the display panel 51 is configured to send alarm information when the detection values are abnormal.

[0027] In the embodiment of the utility model, the upper cover body 1 of the double insurance liquid nitrogen liquid level detection device is an upper cover processed for the corresponding liquid nitrogen tank top opening, when work is needed, the upper cover body 1 can be directly used by being covered on the liquid nitrogen tank. The one side of the upper cover body 1 facing the inside of the liquid nitrogen tank is fixedly connected with a foam plug column as a heat preservation material column 2, after the installation of the upper cover body 1 at the opening of the liquid nitrogen tank is completed, the heat preservation material column 2 is filled on the side wall inside the opening and the tank neck, by using the small space difference characteristic that the foam plastic contains gas, the heat preservation and sealing of the tank body between the inside of the liquid nitrogen tank and the outside of the cover body are achieved. The liquid level sensor 3 and the temperature sensor 4 as detection elements are fixedly connected with the positioning connecting piece 6 through the embedded combination installation form, and then are fixed to the heat preservation material column 2 away from the one end of the upper cover body 1 through the positioning connecting piece 6. In the embodiment of the utility model, the heat preservation material column 2 and the upper cover body 1, and the positioning connecting piece 6 and the heat preservation material column are fixed through gluing, which is simple to assemble and convenient to disassemble and maintain and replace when not in use. After the installation of the upper cover body 1 is completed, the liquid level sensor 3 and the temperature sensor 4 are all extended into the inside of the liquid nitrogen tank and contact with the stored liquid nitrogen, so that the liquid level value in the inside of the liquid nitrogen tank can be detected in real time in the state that the liquid nitrogen tank is not opened, and the value signal is fed back to the electric control mainboard 5 through the related wire harness, and the staff can detect and obtain the remaining amount of the liquid nitrogen in the inside of the liquid nitrogen tank and the real-time temperature information based on the display screen on the display panel 51. In the embodiment of the utility model, the liquid level sensor 3 is a cylindrical capacitive liquid level sensor, the end of which is extended to the bottom of the liquid nitrogen tank, the capacitive liquid level meter has high measurement accuracy, the error is usually within a few millimeters, and the high-precision measurement requirement of the liquid nitrogen liquid level in the assisted reproductive laboratory can be met. While the liquid level sensor 3 is used for liquid level detection, the temperature sensor 4 also feeds back the real-time temperature in the inside of the liquid nitrogen tank to the electric control mainboard 5. Under normal use conditions, the liquid level value detected by the liquid level sensor 3 and the temperature value detected by the temperature sensor 4 are compared and changed synchronously according to the preset proportion. When the liquid level sensor 3 is damaged and fails, the detection value is abnormal, and the comparison value of the data detected synchronously by the temperature sensor 4 exceeds the range threshold value. The display panel 51 sends alarm information to the staff in various forms. For example, sound and light alarm information is sent through the integrated loudspeaker or the flash lamp, or error information is sent through communication to the control host computer connected with the electric control mainboard 5, so that the staff is reminded to confirm and check the equipment in time, and double insurance for liquid level detection is realized.

[0028] The double-insurance liquid nitrogen liquid level detection device provided by the embodiment of the utility model, through the integrated design with the cover body of the traditional liquid nitrogen tank, installs the heat preservation material column 2 for sealing temperature insulation on the inner side surface of the upper cover body 1, and through the way of modifying the heat preservation material column 2, through the positioning connecting piece 6 as the fixed transfer, integrates the liquid level sensor 3 and the temperature sensor 4 as the detection element to the bottom of the heat preservation material column 2, solves the problem that two sensors are not easy to install, ensures that the sensor installation position is fixed and there is no obvious gap. After completing the corresponding installation of the upper cover body 1 and the corresponding liquid nitrogen tank, the liquid level sensor 3 and the temperature sensor 4 can feed back the liquid level data and the temperature data in the tank to the electric control mainboard 5 in real time, and through the display panel 51, the staff can check and confirm, without opening the liquid nitrogen tank. At the same time, through the additional setting of the temperature sensor 4, the double-insurance confirmation in the detection process is realized by using the comparison and change relationship between the internal temperature and the liquid nitrogen liquid level, when the liquid level sensor 3 fails and the comparison of the detection data and the data of the temperature sensor 4 is abnormal, the electric control mainboard 5 can timely send an alarm information to the outside, reminding the staff to confirm and check the equipment in time. Effectively solve the technical problems that the traditional detection method in the related art causes the difficulty in real-time detection of the liquid level in the liquid nitrogen tank and the low detection accuracy due to the structural and detection precision defects.

[0029] Optionally, a first assembly hole 61 and a second assembly hole 62 are arranged on the side end face of the positioning connecting piece 6 away from the heat preservation material column 2, the top of the liquid level sensor 3 is embedded and installed in the first assembly hole 61, the top of the temperature sensor 4 is embedded and installed in the second assembly hole 62, and the heat preservation material column 2 is internally provided with a wire passing hole 21 for the wire harness of the liquid level sensor 3 and the temperature sensor 4 to pass through. Exemplarily, in the embodiment of the utility model, the positioning connecting piece 6 includes a first column body 6a with a larger volume and a second column body 6b with a smaller volume, the axes of the two are parallel, the second column body 6b is integrally formed on the side wall of the first column body 6a, the first assembly hole 61 corresponding to the liquid level sensor 3 is located on the first column body 6a, the second assembly hole 62 corresponding to the temperature sensor 4 is located on the second column body 6b, and when assembling, the parallel installation of the liquid level sensor 3 and the temperature sensor 4 can be completed through corresponding plug-in embedding, and the wire harness connecting the two can be led out through the corresponding hole position at the top of the positioning connecting piece 6 and led to the top through the wire passing hole 21 on the heat preservation material column 2 to be connected with the electric control mainboard 5, so that the structure is simple and the installation is convenient.

[0030] Optionally, the liquid level sensor 3 is a cylindrical capacitive liquid level sensor, a first screw fixing hole 31 is arranged on the side wall of the embedded end of the liquid level sensor 3, and a second screw fixing hole 63 matched with the first screw fixing hole 31 is arranged on the positioning connecting piece 6.

[0031] Optionally, a cylindrical inner positioning sleeve 32 is sleeved on the liquid level sensor 3, the outer diameter of the inner positioning sleeve 32 is greater than the outer diameter of the embedded end of the liquid level sensor 3 and is matched with the inner diameter of the first assembly hole 61, and a third screw fixing hole 321 matched with the first screw fixing hole 31 and the second screw fixing hole 63 is arranged on the side wall of the inner positioning sleeve 32.

[0032] Optionally, the double-insurance liquid nitrogen liquid level detection device further comprises a temperature sensor positioning pipe 7, one end of the temperature sensor positioning pipe 7 is embedded and installed in the second assembly hole 62, a detection through hole 71 is arranged on the other end side wall of the temperature sensor positioning pipe 7 and the end is closed, and the temperature sensor 4 is arranged in the temperature sensor positioning pipe 7 and the probe end is located in the other end of the temperature sensor positioning pipe 7. Figure 3 Exemplarily, in the embodiment of the utility model, the probe of the temperature sensor 4 needs to be stretched into the middle part of the liquid nitrogen tank for temperature measurement, by arranging the temperature sensor positioning pipe 7, the extension position of the probe of the temperature sensor 4 can be guided and limited, the shaking of the probe in the liquid nitrogen tank is avoided, the measurement accuracy is influenced, meanwhile the wire at the rear end of the probe is protected, the end of the temperature sensor positioning pipe 7 is close to the position of the probe, a plurality of detection through holes 71 are circumferentially arranged on the side wall of the temperature sensor positioning pipe 7, the probe can be stably contacted with the internal space of the liquid nitrogen tank, the service life and the detection accuracy of the temperature sensor 4 are effectively improved.

[0033] Exemplarily, in another possible implementation of the present application, the temperature sensor 4 can also adopt a double probe form, wherein the other end of the temperature sensor positioning tube 7 can be in the form of an opening, one probe end of the temperature sensor 4 is exposed from the opening, and the other probe end is arranged at a position where a detection hole 71 is formed, so as to realize multi-point detection.

[0034] Optionally, the other end of the temperature sensor positioning tube 7 is coaxially sleeved with a probe protection tube 72, and the detection hole 71 is arranged on the side wall of the probe protection tube 72. Exemplarily, in the embodiment of the present application, in order to ensure the mechanical strength, the temperature sensor positioning tube 7 is usually made of steel, and the pipe body made of metal is used to fix the temperature sensor 4. There is a problem that the temperature sensor 4 is caused to deviate from the value detected by the probe due to the temperature conduction of the pipe body and other structures above including the liquid nitrogen tank. Therefore, the end probe of the temperature sensor 4 is individually coated by the probe protection tube 72 made of non-metal material, and the detection hole 71 is arranged to ensure that it forms stable contact with the internal space of the liquid nitrogen tank, thereby further improving the detection accuracy.

[0035] Optionally, the probe protection tube 72 and the temperature sensor positioning tube 7 are detachably connected. Exemplarily, in the embodiment of the present application, the probe protection tube 72 and the temperature sensor positioning tube 7 can be connected by threads. When the probe of the temperature sensor 4 fails or is periodically maintained, the probe protection tube 72 can be detached to check and maintain the probe of the temperature sensor 4, thereby improving the practicability.

[0036] Optionally, an inner threaded hole 22 is arranged on the end face of the thermal insulation material column 2 away from the upper cover body 1, an outer threaded column 64 is arranged on the top of the positioning connecting piece 6, and the outer threaded column 64 is screwed with the inner threaded hole 22. Exemplarily, in the embodiment of the present application, the first column body 6a with a large volume is formed with the outer threaded column 64 on the top, which is screwed and embedded into the inner threaded hole 22 arranged on the bottom end face of the thermal insulation material column 2. The structure is simple, easy to disassemble and assemble, and conducive to the separate maintenance and replacement of the positioning connecting piece 6 and the thermal insulation material column 2.

[0037] Optionally, the double insurance liquid nitrogen liquid level detection device further comprises a battery box 8, an end face of the thermal insulation material column 2 connected with the upper cover body 1 is provided with a battery box mounting hole 23, and the battery box 8 is arranged in the battery box mounting hole 23 and electrically connected with the electric control main board 5. Exemplarily, in the embodiment of the present application, the battery box mounting hole 23 is arranged on the end face of the thermal insulation material column 2 connected with the upper cover body 1, and the battery box 8 storing a large-capacity rechargeable lithium battery is arranged in the battery box mounting hole 23. After the upper cover body 1 is arranged on the thermal insulation material column 2 and is fixed by gluing, it can ensure that the sensors and the electric control main board 5 can work continuously for a long time, thereby improving the endurance.

[0038] Exemplarily, in the embodiment of the utility model, the end surface of the heat preservation material column 2 connected with the upper cover body 1 is provided with a sealing ring 9 around the battery box mounting hole 23, after gluing and pressing and fixed connection, the sealing ring 9 is used to block the possible assembly gap, prevent the water vapor from entering the internal battery box 8 and related wire harness to cause short circuit damage due to the water vapor liquefaction reaction near the liquid nitrogen tank, further improve the work safety.

[0039] Unless otherwise defined, technical terms or scientific terms used herein shall have the ordinary meaning as understood by a person with ordinary skill in the art to which the utility model belongs. The "first", "second" and similar words used in the utility model patent application specification and claims do not represent any order, quantity or importance, but are used to distinguish different components. Similarly, "one" or "a" and similar words do not represent quantity limitation, but represent the existence of at least one. "Include" or "contain" and similar words mean that the elements or objects appearing before "include" or "contain" cover the elements or objects listed after "include" or "contain" and their equivalents, and do not exclude other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent relative positional relationship, when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] The above is only optional embodiment of the utility model, and does not limit the utility model, any modification, equivalent replacement, improvement and the like made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A dual safety liquid nitrogen level detection device, characterized by, Include: The upper cover body (1), the heat preservation material column (2), the liquid level sensor (3), the temperature sensor (4) and the electric control mainboard (5), The electric control mainboard (5) is installed on the upper cover body (1), the heat preservation material column (2) is connected to the side of the upper cover body (1), the heat preservation material column (2) is provided with a positioning connecting piece (6) at the end away from the upper cover body (1), the liquid level sensor (3) and the temperature sensor (4) are arranged side by side and embeddedly installed on the positioning connecting piece (6), the liquid level sensor (3) and the temperature sensor (4) are electrically connected with the electric control mainboard (5), the electric control mainboard (5) is provided with a display panel (51) for displaying the detection values of the liquid level sensor (3) and the temperature sensor (4), and is configured to send alarm information when the detection values are abnormal.

2. The dual safety liquid nitrogen level detection device of claim 1, wherein, The first assembly hole (61) and the second assembly hole (62) are arranged at intervals on the side end face of the positioning connecting piece (6) away from the heat preservation material column (2), the top of the liquid level sensor (3) is embeddedly installed in the first assembly hole (61), the top of the temperature sensor (4) is embeddedly installed in the second assembly hole (62), and the heat preservation material column (2) is provided with a wire passing hole (21) for the wire harness of the liquid level sensor (3) and the temperature sensor (4) to pass through.

3. The dual safety liquid nitrogen level detection device of claim 2, wherein, The liquid level sensor (3) is a cylindrical capacitive liquid level sensor, the embedded end side wall of the liquid level sensor (3) is provided with a first screw fixing hole (31), and the positioning connecting piece (6) is provided with a second screw fixing hole (63) matched with the first screw fixing hole (31).

4. The dual safety liquid nitrogen level detection device of claim 3, wherein, A cylindrical inner positioning sleeve (32) is sleeved on the liquid level sensor (3), the outer diameter of the inner positioning sleeve (32) is greater than the embedded end outer diameter of the liquid level sensor (3) and matches the inner diameter of the first assembly hole (61), and the side wall of the inner positioning sleeve (32) is provided with a third screw fixing hole (321) matched with the first screw fixing hole (31) and the second screw fixing hole (63).

5. The dual safety liquid nitrogen level detection device of claim 2, wherein, The double insurance liquid nitrogen liquid level detection device further comprises a temperature sensor positioning pipe (7), one end of the temperature sensor positioning pipe (7) is embeddedly installed in the second assembly hole (62), the other end side wall of the temperature sensor positioning pipe (7) is provided with a detection through hole (71) and the end is closed, and the temperature sensor (4) is arranged in the temperature sensor positioning pipe (7) and the probe end is located in the other end of the temperature sensor positioning pipe (7).

6. The dual safety liquid nitrogen level detection device of claim 5, wherein, The other end of the temperature sensor positioning pipe (7) is coaxially sleeved with a probe protection pipe (72), and the detection through hole (71) is arranged on the side wall of the probe protection pipe (72).

7. The dual safety liquid nitrogen level detection device of claim 6, wherein, The probe protection pipe (72) and the temperature sensor positioning pipe (7) are detachably connected.

8. The dual safety liquid nitrogen level detection device according to any one of claims 1 to 7, characterized in that, The end face of the heat preservation material column (2) away from the upper cover body (1) is provided with an inner threaded hole (22), the top of the positioning connecting piece (6) is provided with an outer threaded column (64), and the outer threaded column (64) is screwed with the inner threaded hole (22).

9. The dual safety liquid nitrogen level detection device according to any one of claims 1 to 7, characterized in that, The double safety liquid nitrogen liquid level detection device further comprises a battery box (8), the end face of the heat preservation material column (2) connected with the upper cover body (1) is provided with a battery box mounting hole (23), and the battery box (8) is arranged in the battery box mounting hole (23) and electrically connected with the electric control mainboard (5).

10. The dual safety liquid nitrogen level detection device according to any one of claims 1 to 7, characterized in that, The heat preservation material column (2) is a foam plug column body.

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