Liquid hydrogen storage tank liquid level meter based on ultrasonic ranging technology

Abstract

The invention relates to a liquid hydrogen storage tank liquid level meter based on an ultrasonic ranging technology, which comprises a floater, a floater limiting net cylinder, an ultrasonic ranging probe, an aviation plug, a cable and a computer, and ensures the effectiveness and reliability of the liquid level meter under the design condition of a liquid hydrogen tank. The buoy liquid level meter and the ultrasonic ranging technology are combined, and compared with a traditional capacitive liquid level meter, the liquid level meter has the advantages of being small in size, convenient to install and low in cost.

Description

Technical Field

[0001] The invention relates to the field of liquid hydrogen, and in particular to a liquid hydrogen storage tank level meter based on ultrasonic ranging technology. Background Art

[0002] In recent years, with the proposal of the "dual carbon" goal, hydrogen fuel cells have begun to develop rapidly in my country. Among them, liquid hydrogen has received extensive attention and research due to its high storage density and low storage pressure. Liquid hydrogen as a medium is usually more common in liquid rocket engines and other fields, and capacitive level gauges are mostly used for liquid level measurement. As liquid hydrogen gradually enters the civilian market, liquid hydrogen tank level gauges must meet the actual conditions of mass production and installation and maintenance when used. If capacitive level gauges continue to be used, there will be a high economic cost. Other commonly used level gauges such as radar level gauges, buoy level gauges, differential pressure level gauges, etc. cannot achieve effective liquid level measurement due to the special physical properties of liquid hydrogen. For example, a linkage mechanical device needs to be set on the buoy of the buoy level gauge, so it cannot float in low-density liquid hydrogen and achieve normal linkage with the mechanical device, resulting in the inability to achieve effective measurement. Although ultrasonic ranging technology is a conventional technology, it cannot be used for liquid hydrogen level measurement because liquid hydrogen cannot reflect it. The present invention overcomes technical prejudice and combines a float level meter with ultrasonic ranging technology to obtain a low-cost and reliable liquid hydrogen storage tank level meter, which has great civilian market value.

[0003] The applicant, Beijing Aerospace Testing Technology Research Institute, is the only unit in China that has the conditions for large-scale testing of liquid hydrogen and has rich experience in the production, use and testing of liquid hydrogen. Since the use of civilian liquid hydrogen is still in the development stage in China and there are few corresponding standards, the present invention can provide a solution for liquid level measurement of liquid hydrogen storage tanks. Summary of the invention

[0004] The present application relates to a liquid hydrogen tank level gauge based on ultrasonic ranging technology, including a float, an ultrasonic ranging probe, an aviation plug, a float limit net tube, a cable, and a computer. The float floats on the liquid hydrogen surface, the aviation plug is fixed to the top of the liquid hydrogen tank, the ultrasonic ranging probe is connected to the internal interface of the aviation plug, one end of the cable is connected to the external interface of the aviation plug, and the other end of the cable is connected to the computer. The ultrasonic ranging probe can emit ultrasonic waves and receive reflected ultrasonic waves at the design pressure and temperature of the liquid hydrogen tank, and the float is placed in the float limit net tube. The bottom of the float limit net tube is fixed to the bottom of the liquid hydrogen tank.

[0005] The float has an internal vacuum structure, an opaque upper surface, an average density lower than that of the liquid hydrogen medium, and is made of a material that can withstand the design pressure and temperature of the liquid hydrogen storage tank without deformation.

[0006] The float may also be a structure filled with helium. The helium pressure inside the float can reduce the pressure inside the liquid hydrogen storage tank, and the average density is lower than that of the liquid hydrogen medium.

[0007] The upper surface of the float is light-proof, preferably diffusely reflective and light-proof, which can ensure that the laser is reflected to the laser ranging probe.

[0008] The shape of the float can be a cuboid, a cube, a trapezoid, a butterfly, a round cake, etc., preferably a butterfly or a round cake. The material of the float is preferably aluminum alloy, stainless steel, carbon fiber, or hard plastic.

[0009] The ultrasonic wave emitted by the ultrasonic ranging probe can reach the upper surface of the float and be reflected. The float is placed in the float limiting mesh cylinder and can float up and down with the liquid hydrogen level, but can only float up and down within the restricted area of ​​the float limiting mesh cylinder.

[0010] The ultrasonic ranging probe can transmit ultrasonic waves and receive reflected ultrasonic waves at the design pressure and temperature of the liquid hydrogen storage tank, and transmit energy and signals with the aviation plug.

[0011] The internal interface of the aviation plug is connected to the ultrasonic ranging probe, and the external interface of the aviation plug is connected to the cable, which is responsible for the transmission of energy and signals and ensures that the medium in the liquid hydrogen storage tank will not leak out.

[0012] The bottom of the float limiting mesh cylinder is fixed to the bottom of the liquid hydrogen storage tank, and the side of the cylinder is a mesh structure, which can ensure that the liquid hydrogen levels inside and outside the float limiting mesh cylinder are equal, and the float will not leave the float limiting mesh cylinder with the fluctuation of the liquid hydrogen level; the top of the float limiting mesh cylinder is open, which can ensure that the float can be installed in the float limiting mesh cylinder, and the ultrasonic waves it emits and reflects are not blocked.

[0013] The two ends of the cable are connected to the aviation plug and the computer respectively for energy and signal transmission. The computer is connected to the cable through the aviation plug and is responsible for sending instructions to the ultrasonic probe, providing power, and receiving the reflected light signal of the ultrasonic probe. The distance from the ultrasonic probe to the float is calculated based on the time difference from the emission to the reception of the ultrasonic wave, and the liquid hydrogen level is further calculated.

[0014] The liquid hydrogen storage tank may be a liquid hydrogen storage tank placed on a vehicle, a submarine, a ship, a warship, etc.

[0015] The working principle of the present invention is that the float 1 floats on the liquid hydrogen surface, and moves up and down with the increase and decrease of the liquid hydrogen level, thereby causing the distance between the float 1 and the ultrasonic ranging probe 2 to change. The ultrasonic ranging probe 2 is directed by the computer 6 through the aviation plug 3 and the cable 5, and the time difference between the emission and reflection of the ultrasonic wave is used to calculate the distance from the ultrasonic probe 2 to the float 1, and further calculate the liquid hydrogen level.

[0016] The specific plan is as follows:

[0017] When working, the computer 6 is connected to the ultrasonic ranging probe 2 through the cable 5 and the aviation plug 3. When it is necessary to measure the liquid level of the liquid hydrogen tank, it issues instructions and provides electrical energy to allow the ultrasonic ranging probe 2 to emit ultrasonic waves. The ultrasonic ranging probe 2 emits a beam of ultrasonic waves to the float 1. The ultrasonic waves reach the upper surface of the float 1 floating on the liquid hydrogen at the speed of sound and are reflected. The photoelectric element of the ultrasonic ranging probe 2 receives the ultrasonic waves reflected from the upper surface of the float 1 and generates a signal, which is transmitted to the computer 6 through the aviation plug 3 and the cable 5. The computer 6 calculates the distance from the ultrasonic probe 2 to the upper surface of the float 1 based on the time difference from the emission to the reception of the ultrasonic wave. The liquid hydrogen level can be calculated according to the following formula:

[0018] h=H-h1-h2-h3

[0019] Where, h is the liquid level height of the liquid hydrogen storage tank;

[0020] h1——the distance from ultrasonic probe 2 to the upper surface of float 1;

[0021] h2——the distance from ultrasonic probe 2 to the top of the inner surface of the liquid hydrogen storage tank;

[0022] h3——The height of the upper surface of float 1 above the liquid hydrogen level. h3 can be based on the average density ρ of the float 浮子 , liquid hydrogen density ρ 液氢 The shape parameters of the float are calculated comprehensively. For example, when the float is a round pancake, h3=(ρ 液氢 -ρ 浮子 )×longitudinal height of float / ρ 液氢 ; H——the distance between the top and bottom of the inner surface of the liquid hydrogen storage tank;

[0023] Compared with the prior art, the present invention has the advantages that:

[0024] 1. The structure is simple, and the components included in the system are easy to process and manufacture.

[0025] 2. Easy to install and easy to maintain in the civilian market.

[0026] 3. Low cost, production and installation costs are significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the schematic diagram of the liquid hydrogen storage tank level gauge.

[0028] Figure 2 It is a schematic diagram of the symbols in the formula for calculating the liquid level height of the liquid hydrogen storage tank.

[0029] Reference numerals: 1 float, 2 ultrasonic distance measuring probe, 3 aviation plug, 4 float limit net cylinder, 5 cable, 6 computer DETAILED DESCRIPTION

[0030] Example 1

[0031] A liquid hydrogen storage tank level gauge based on ultrasonic ranging technology includes a float 1, an ultrasonic ranging probe 2, an aviation plug 3, a float 1 limiting net tube 4, a cable 5, and a computer 6. The float 1 floats on the liquid hydrogen surface, the aviation plug 3 is fixed to the top of the liquid hydrogen tank, the ultrasonic ranging probe 2 is connected to the internal interface of the aviation plug 3, one end of the cable 5 is connected to the external interface of the aviation plug 3, and the other end of the cable 5 is connected to the computer. The ultrasonic ranging probe 2 can emit ultrasonic waves and receive reflected ultrasonic waves at the design pressure and temperature of the liquid hydrogen storage tank, and the float 1 is placed in the float limiting net tube 4. The bottom of the float limiting net tube 4 is fixed to the bottom of the liquid hydrogen storage tank.

[0032] The ultrasonic wave emitted by the ultrasonic ranging probe 2 can reach the upper surface of the float 1 and be reflected. The float 1 is placed in the float limiting mesh tube 4 and can float up and down with the liquid hydrogen level, but can only float up and down within the restricted area of ​​the float limiting mesh tube 4; the bottom of the float limiting mesh tube 4 is fixed to the bottom of the liquid hydrogen storage tank and immersed in the liquid hydrogen medium in the storage tank; the ultrasonic ranging probe 2 is connected to the internal interface of the aviation plug 3 of the storage tank and fixed to the top of the liquid hydrogen tank; the external interface of the storage tank of the aviation plug 3 is connected to the cable 5, and the cable 5 is connected to the computer 6.

[0033] The float 1 is butterfly-shaped and has an internal vacuum structure, which can withstand the design pressure and temperature of the liquid hydrogen storage tank without deformation; the average density of the float 1 is lower than that of the liquid hydrogen medium, and the material is aluminum alloy, which can ensure that the float 1 floats in the liquid hydrogen; the upper surface of the float 1 is diffusely reflective and has strong ultrasonic reflection ability, which can ensure that the ultrasonic wave is reflected to the ultrasonic ranging probe 2.

[0034] The ultrasonic ranging probe 2 can transmit ultrasonic waves and receive reflected ultrasonic waves at the design pressure and temperature of the liquid hydrogen storage tank, and transmit energy and signals with the aviation plug 3.

[0035] The internal interface of the aviation plug 3 is connected to the ultrasonic ranging probe 2, and the external interface of the aviation plug 3 is connected to the cable 5, which is responsible for the transmission of energy and signals and ensures that the medium in the liquid hydrogen storage tank does not leak out.

[0036] The bottom of the float limiting mesh tube 4 is fixed to the bottom of the liquid hydrogen storage tank; the cylindrical surface is a mesh structure, which can ensure that the liquid hydrogen levels inside and outside the float limiting mesh tube 4 are equal, and the float 1 will not leave the float limiting mesh tube 4 with the fluctuation of the liquid hydrogen level; the top is open, which can ensure that the float 1 can be installed in the float limiting mesh tube 4, and the ultrasonic waves it emits and reflects are not blocked.

[0037] Both ends of the cable 5 are connected to the aviation plug 3 and the computer 6 respectively for energy and signal transmission.

[0038] The computer 6 is connected to the cable 5 through the aviation plug 3 and is responsible for sending instructions to the ultrasonic probe 2, providing power, and receiving the reflected light signal of the ultrasonic probe 2. The distance from the ultrasonic probe 2 to the float 1 is calculated based on the time difference from the emission to the reception of the ultrasonic wave, and the liquid hydrogen level is further calculated according to the formula (h=H-h1-h2-h3).

[0039] Where, h is the liquid level height of the liquid hydrogen storage tank;

[0040] h1——the distance from ultrasonic probe 2 to the upper surface of float 1;

[0041] h2——the distance from ultrasonic probe 2 to the top of the inner surface of the liquid hydrogen storage tank;

[0042] h3——The height of the upper surface of float 1 above the liquid hydrogen level. h3 can be based on the average density ρ of the float 浮子 , liquid hydrogen density ρ 液氢 , the shape parameters of the float 1 are obtained by comprehensive calculation;

[0043] H——the distance between the top and bottom of the inner surface of the liquid hydrogen storage tank;

[0044] Example 2

[0045] Different from the first embodiment, the float 1 is in the shape of a round cake and is made of aluminum alloy.

[0046] Example 3

[0047] Different from the first embodiment, the float 1 is butterfly-shaped and made of stainless steel.

[0048] Example 4

[0049] Different from the first embodiment, the float 1 is in the shape of a round cake and is made of stainless steel.

[0050] Example 5

[0051] Different from the first embodiment, the float 1 is in a butterfly shape and is made of carbon fiber.

[0052] Example 6

[0053] Different from the first embodiment, the float 1 is in the shape of a round cake and is made of carbon fiber.

[0054] Example 7

[0055] Different from the first embodiment, the float 1 is in the shape of a butterfly and is made of hard plastic.

[0056] Example 8

[0057] Different from the first embodiment, the float 1 is in the shape of a round cake and is made of hard plastic.

[0058] Embodiments 9 to 16

[0059] Different from Examples 1 to 8, the interior of the float 1 is not a vacuum structure, but a helium-filled structure. The helium pressure in the float can reduce the pressure in the liquid hydrogen storage tank, and the average density is lower than that of the liquid hydrogen medium.

Claims

1. A liquid hydrogen tank level meter based on ultrasonic ranging technology, characterized in that: The invention comprises a float (1), an ultrasonic distance measuring probe (2), an aviation plug (3), a float limiting mesh cylinder (4), a cable (5), and a computer (6). The float (1) floats on the liquid hydrogen surface, the aviation plug (3) is fixed on the top of the liquid hydrogen tank, the ultrasonic distance measuring probe (2) is connected to the internal interface of the aviation plug (3) in the storage tank, one end of the cable (5) is connected to the external interface of the aviation plug (3) in the storage tank, and the other end of the cable (5) is connected to the computer (6). The ultrasonic distance measuring probe (2) can emit ultrasonic waves and receive reflected ultrasonic waves under the design pressure and temperature of the liquid hydrogen storage tank. The float (1) is placed in the float limiting mesh cylinder (4), and the bottom of the float limiting mesh cylinder (4) is fixed to the bottom of the liquid hydrogen storage tank.

2. The liquid hydrogen storage tank level meter based on ultrasonic ranging technology according to claim 1 is characterized in that: The float (1) is filled with helium, has an opaque upper surface, has an average density lower than that of the liquid hydrogen medium, and is made of a material that can withstand the design pressure and temperature of the liquid hydrogen storage tank without deformation.

3. The liquid hydrogen storage tank level meter based on ultrasonic ranging technology according to any one of claim 1, characterized in that: The float (1) has an internal vacuum structure, an opaque upper surface, an average density lower than that of the liquid hydrogen medium, and is made of a material that can withstand the design pressure and temperature of the liquid hydrogen storage tank without deformation.

4. The liquid hydrogen storage tank level meter based on ultrasonic ranging technology according to claim 2 or 3 is characterized in that: The upper surface of the float (1) is diffusely reflective and opaque, thereby ensuring that the ultrasonic wave is reflected to the ultrasonic distance measuring probe (2).

5. The liquid hydrogen storage tank level meter based on ultrasonic ranging technology according to claim 2 or 3, characterized in that: The float (1) is in the shape of a butterfly.

6. The liquid hydrogen storage tank level meter based on ultrasonic ranging technology according to claim 2 or 3, characterized in that: The float (1) is in the shape of a round cake.

7. The liquid hydrogen tank level meter based on ultrasonic ranging technology according to claim 2 or 3 is characterized in that: The material of the float (1) is aluminum alloy.

8. The liquid hydrogen tank level meter based on ultrasonic ranging technology according to claim 2 or 3 is characterized in that: The material of the float (1) is stainless steel.

9. The liquid hydrogen tank level gauge based on ultrasonic ranging technology according to claim 2 or 3, characterized in that: The material of the float (1) is carbon fiber.

10. The liquid hydrogen tank level meter based on ultrasonic ranging technology according to claim 2 or 3, characterized in that: The material of the float (1) is hard plastic.

Images