A liquid level measuring instrument for low temperature and high pressure containers

Abstract

The present invention relates to the technical field of liquid level gauges, and in particular to a liquid level measuring instrument for cryogenic and high-pressure containers, which aims to solve the problem that when measuring the liquid level of cryogenic and high-pressure containers, the pressure and temperature of the medium may easily cause the measurement data to be erroneous. The invention comprises: a pressure measuring container; the liquid level gauge comprises a gas phase tube, a liquid phase tube and a differential pressure transmitter, one end of the gas phase tube and the liquid phase tube are both connected to the pressure measuring container; a gas-liquid drainage component; the differential pressure transmitter is used to measure the liquid content in the pressure measuring container through the pressure of the gas or liquid in the gas phase tube and the liquid phase tube, and the gas-liquid drainage component is used to separate the gas and liquid in the gas phase tube or the liquid phase tube. The gas in the cryogenic and high-pressure container enters the gas phase tube, and the liquid enters the liquid phase tube. The gas-liquid drainage component can process the medium at the gas phase tube and the liquid phase tube respectively, to avoid the medium directly entering the gas phase tube or the liquid phase tube, and to prevent the problem of unstable measurement data caused by factors such as pressure fluctuations.

Description

Technical Field

[0001] The invention relates to the technical field of liquid level gauges, and in particular to a liquid level measuring instrument for a low-temperature and high-pressure container. Background Art

[0002] In industrial storage tanks (such as liquefied natural gas tanks, liquid oxygen tanks, etc.) under low temperature and high pressure environments, accurate measurement of liquid level is a key link to ensure process safety and efficient operation. The unique operating environment of these tanks includes extremely low temperatures, high internal pressures, and multiphase fluids (liquid and gas coexist), which poses many challenges to the liquid level measurement system.

[0003] At present, common liquid level measurement methods include float type, ultrasonic type, radar type and differential pressure type liquid level measurement, among which float type liquid level meter is easy to fail due to low temperature freezing of liquid or damage of float; ultrasonic and radar type liquid level meter are affected by the instability of gas phase layer in low temperature environment, and the measurement results may have large errors. In addition, these methods are complicated to install and maintain, and the cost is high, which makes it difficult to meet the requirements of economy and reliability in some occasions.

[0004] The differential pressure level gauge is a classic technology in liquid level measurement. It calculates the liquid level by measuring the pressure difference between the static pressure of the liquid at the bottom of the container and the gas pressure at the top. The differential pressure level gauge has a simple structure and high precision, and is particularly suitable for high-pressure environments. The liquid in the low-temperature and high-pressure storage tank has the characteristics of high density, low temperature, and easy formation of a complex interface with the gas phase. As mentioned in patents CN202110521635.6 and CN202310867831.8, the accuracy and stability of the liquid level measurement of the differential pressure level gauge directly affect the safety and operating efficiency of the system. During the measurement process, there will be problems such as pipeline frost blockage and pressure balance, which will lead to unstable measurement accuracy. Summary of the invention

[0005] The technical problem to be solved by the present invention is that when measuring the liquid level height of a low-temperature and high-pressure container, the medium in the container is likely to affect the liquid level meter, resulting in inaccurate measurement accuracy. A liquid level measuring instrument for a low-temperature and high-pressure container is provided, which can effectively reduce the adverse conditions after the gas and liquid medium in the container enter the liquid level meter and reduce measurement errors.

[0006] The present invention is achieved through the following technical solutions:

[0007] A liquid level measuring instrument for a low-temperature and high-pressure container, comprising:

[0008] A pressure measuring container, wherein the pressure measuring container is provided with a liquid to be measured, and a distance exists between the liquid level and the inner top surface of the pressure measuring container;

[0009] A liquid level gauge, the liquid level gauge comprising a gas phase tube, a liquid phase tube and a differential pressure transmitter, one end of the gas phase tube and the liquid phase tube are both in communication with the pressure measuring container, one end of the gas phase tube and the liquid phase tube relative to the pressure measuring container are respectively connected to two ends of the differential pressure transmitter, the connection end of the gas phase tube is higher than the maximum liquid level of the liquid, and the liquid phase tube is connected to the bottom of the pressure measuring container;

[0010] A gas-liquid drainage component, which is respectively arranged at the connection ends of the gas phase pipe and the liquid phase pipe and the pressure measuring container;

[0011] Among them, the gas phase tube is used to introduce the gas in the pressure measuring container, the liquid phase tube is used to introduce the liquid in the pressure measuring container, the differential pressure transmitter is used to measure the liquid level in the pressure measuring container through the pressure of the gas or liquid in the gas phase tube and the liquid phase tube, and the gas-liquid drainage component is used to separate the gas and liquid in the gas phase tube or the liquid phase tube.

[0012] In the above technical solution, a differential pressure liquid level gauge is used to effectively measure the liquid level of the cryogenic and high-pressure container. The gas in the cryogenic and high-pressure container enters the gas phase tube, and the liquid enters the liquid phase tube. The gas-liquid drainage component can process the medium at the gas phase tube and the liquid phase tube respectively to avoid the medium directly entering the gas phase tube or the liquid phase tube, which may cause unstable measurement data due to pressure fluctuations and other factors.

[0013] In some optional technical solutions, the gas-liquid drainage component includes a first pressure transmission tube and a first pressure conducting tube, the first pressure transmission tube is horizontally arranged, the first pressure transmission tube is connected to the first pressure conducting tube, the first pressure conducting tube is connected to the gas phase tube, and the first pressure conducting tube is located above the first pressure transmission tube.

[0014] In the above technical solution, the first pressure transmission tube and the first pressure conducting tube are used to separate the gas phase tube and the pressure measuring container to avoid direct contact, and the first pressure conducting tube is used to introduce the gas entering the first pressure transmission tube into the gas phase tube.

[0015] In some optional technical solutions, one end of the gas phase tube close to the pressure measuring container is connected to the first pressure conducting tube with a second pressure conducting tube, the second pressure conducting tube is L-shaped, and the second pressure conducting tube is located above the first pressure conducting tube.

[0016] In the above technical solution, the first pressure-conducting pipe introduces the gas into the gas phase pipe through the second pressure-conducting pipe, so that the gas phase pipe is far away from the pressure measuring container to avoid affecting the measurement data.

[0017] In some optional technical solutions, a first flow guide portion is provided in the middle of the tube body of the first pressure transmission tube, the center of the first flow guide portion is connected to the first pressure transmission tube, the opening diameter of the first flow guide portion located above the first pressure transmission tube gradually decreases upward, and the opening diameter of the first flow guide portion located below the first pressure transmission tube gradually decreases downward, the first pressure transmission tube is connected to the top of the first flow guide portion, and a drain pipe is connected to the bottom of the first flow guide portion, the drain pipe is connected to the pressure measuring container, and the outlet of the drain pipe is higher than the maximum liquid level of the pressure measuring container.

[0018] In the above technical solution, the first guide portion can temporarily store the condensed droplets of gas entering the first pressure transmission tube, and return them to the pressure measuring container through the drain pipe, so as to avoid the presence of impurities other than gas in the gas phase tube and affect the measurement data. The upper part of the first guide portion is used to gather gas to enter the gas phase tube.

[0019] In some optional technical solutions, the inner circumferential surface of the first pressure transmission tube is inclined downward toward the pressure measuring container.

[0020] In the above technical solution, after the gas entering the first pressure transmission tube is condensed and liquefied into liquid droplets, it can directly return to the pressure measuring container along the inclined surface of the first pressure transmission tube.

[0021] In some optional technical solutions, the gas-liquid drainage component also includes a second pressure transmission tube and a bent tube, the second pressure transmission tube is horizontally arranged, the second pressure transmission tube is connected to the liquid phase tube through the bent tube, the bent tube is bent at 90°, the upper end of the bent tube is connected to the second pressure transmission tube, and the lower end of the bent tube is connected to the liquid phase tube.

[0022] In the above technical solution, the second pressure transmission tube and the bent tube are also used to separate the liquid phase tube and the pressure measuring container to prevent the low-temperature and high-pressure liquid medium from directly contacting the liquid phase tube and affecting the measurement accuracy due to pressure fluctuations.

[0023] In some optional technical solutions, a second flow guide portion is provided on the second pressure transmission tube, the second flow guide portion is provided close to the bent tube, and the second flow guide portion is concave and converges in an arc shape toward the central axis of the second pressure transmission tube.

[0024] In the above technical solution, the liquid entering the liquid phase tube will generate bubbles due to pressure changes and the liquid medium, and the second guide part is used to collect the bubbles at the bent tube.

[0025] In some optional technical solutions, a fixed shaft is arranged inside the vertical end of the bent tube, a rotating drum is rotatably connected to the fixed shaft, a plurality of guide plates are arranged on the rotating drum, and the guide plates are spirally arranged along the rotating drum. A spiral tube is also connected between the bent tube and the liquid phase tube, and the maximum height of the spiral tube is always lower than the height of the second pressure transmission tube.

[0026] In the above technical solution, when the liquid flows downward along the bent tube, the spiral tube rotates along the fixed axis due to the gravity and inertia of the falling fluid, separating the bubbles into smaller bubbles and preventing the small bubbles from flowing along the bent tube to the liquid phase tube.

[0027] In some optional technical solutions, a bypass pipe is connected above the bending part of the bent pipe, the bypass pipe is connected to the gas phase pipe, and a one-way valve is arranged on the bypass pipe.

[0028] In the above technical solution, bubbles gathered at the bent pipe can rise along the bypass pipe, and the gas from the broken bubbles enters the gas phase pipe along the bypass pipe. The one-way valve can prevent gas reflux and prevent liquid from entering the bypass pipe.

[0029] In some optional technical solutions, both the first pressure transmission pipe and the second pressure transmission pipe are provided with a thermal insulation layer.

[0030] In the above technical solution, the insulation layer is used for heat preservation to prevent the temperature difference between the first pressure transmission pipe and the second pressure transmission pipe from being too large, so that the medium encountering low temperature will freeze at the pipe mouth.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1. In the present invention, a first pressure transmission pipe and a first pressure guiding pipe are arranged at the gas phase pipe of the differential pressure level gauge to avoid direct contact between the gas phase pipe and the pressure measuring container. The gas in the pressure measuring container enters the first pressure transmission pipe. When the high-pressure and low-temperature gas enters the first pressure transmission pipe at normal temperature and pressure, the gas will expand and cool down, condense on the inner wall of the pipe and finally form droplets and frost, and enter the pressure measuring container along the drain pipe. The first pressure transmission pipe and the first pressure guiding pipe separate the gas phase pipe from the pressure measuring container to avoid impurities entering the gas phase pipe and affecting the measurement accuracy.

[0033] 2. In the present invention, a second pressure transmission tube and a bent tube are provided at the liquid phase tube of the differential pressure level gauge. The liquid in the pressure measuring container is partially vaporized to form bubbles due to entering the low-pressure area or being affected by external heat transfer. The bent tube and the second guide portion are used to separate the bubbles and retain the bubbles in the bent tube at the same time. A bypass tube is provided above the bent tube. The bypass tube is used to introduce the gas after the bubbles are broken into the gas phase tube, which can keep the gas pressure and hydraulic pressure at both ends of the differential pressure transmitter stable while discharging excess gas in the liquid phase tube, thereby improving the stability of the measurement data. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0035] Figure 1 It is a structural schematic diagram of the present invention;

[0036] Figure 2 is a cross-sectional view of the present invention;

[0037] Figure 3 This is a schematic structural diagram of the first pressure transmission pipe in Example 1 of the present invention;

[0038] Figure 4 This is a schematic structural diagram of the first pressure transmission pipe in Example 4 of the present invention;

[0039] Figure 5 It is a cross-sectional view between the second pressure transmission tube and the liquid phase tube in the present invention.

[0040] The reference numerals represent:

[0041] 1. Pressure measuring container; 2. First pressure transmission tube; 21. First pressure transmission tube; 22. Second pressure transmission tube; 23. Drain pipe; 3. First flow guide part; 4. Second pressure transmission tube; 5. Second flow guide part; 6. Bending tube; 61. Rotating drum; 62. Spiral tube; 63. Bypass tube; 631. One-way valve; 7. Gas phase tube; 8. Liquid phase tube; 9. Differential pressure transmitter. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and drawings. The schematic implementation modes and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention. It should be noted that the present invention is already in the actual development and use stage.

[0043] Example 1

[0044] like Figures 1 to 5 As shown, this embodiment provides a liquid level measuring instrument for a low-temperature and high-pressure container, comprising:

[0045] A pressure measuring container 1, in which a liquid to be measured is arranged, and there is a distance between the liquid level and the inner top surface of the pressure measuring container 1;

[0046] The liquid level gauge comprises a gas phase tube 7, a liquid phase tube 8 and a differential pressure transmitter 9. One end of the gas phase tube 7 and the liquid phase tube 8 are both connected to the pressure measuring container 1. One end of the gas phase tube 7 and the liquid phase tube 8 relative to the pressure measuring container 1 are respectively connected to the two ends of the differential pressure transmitter 9. The connection end of the gas phase tube 7 is higher than the maximum liquid level of the liquid, and the liquid phase tube 8 is connected to the bottom of the pressure measuring container 1.

[0047] Gas-liquid drainage components, which are respectively arranged at the connection ends of the gas phase pipe 7 and the liquid phase pipe 8 and the pressure measuring container 1;

[0048] Among them, the gas phase tube 7 is used to introduce the gas into the pressure measuring container 1, the liquid phase tube 8 is used to introduce the liquid into the pressure measuring container 1, the differential pressure transmitter 9 is used to measure the liquid level in the pressure measuring container 1 through the pressure of the gas or liquid in the gas phase tube 7 and the liquid phase tube 8, and the gas-liquid drainage component is used to separate the gas and liquid in the gas phase tube 7 or the liquid phase tube 8.

[0049] like Figures 1 to 3 As shown, the gas-liquid drainage component includes a first pressure transmission pipe 2 and a first pressure transmission pipe 21. The first pressure transmission pipe 2 is horizontally arranged, the first pressure transmission pipe 2 and the first pressure transmission pipe 21 are connected, the first pressure transmission pipe 21 is connected to the gas phase pipe 7, and the first pressure transmission pipe 21 is located above the first pressure transmission pipe 2.

[0050] like Figures 1 to 3 As shown, one end of the gas phase pipe 7 close to the pressure measuring container 1 is connected to the second pressure guiding pipe 22 toward the first pressure guiding pipe 21 . The second pressure guiding pipe 22 is L-shaped and is located above the first pressure guiding pipe 21 .

[0051] like Figures 1 to 3 As shown, a first flow guide portion 3 is provided in the middle of the tube body of the first pressure transmission tube 2, the center of the first flow guide portion 3 is connected to the first pressure transmission tube 2, the diameter of the first flow guide portion 3 located above the first pressure transmission tube 2 gradually decreases upward, and the diameter of the first flow guide portion 3 located below the first pressure transmission tube 2 gradually decreases downward, the first pressure transmission tube 21 is connected to the upper part of the first flow guide portion 3, and the lower part of the first flow guide portion 3 is connected to a drain pipe 23, the drain pipe 23 is connected to the pressure measuring container 1, and the outlet of the drain pipe 23 is higher than the maximum liquid level of the pressure measuring container 1.

[0052] Specifically, the pressure measuring container 1 mentioned in this embodiment is a low-temperature and high-pressure container, and the liquid level gauge is a differential pressure liquid level gauge. A through hole is opened on the pressure measuring container 1, and a valve is arranged at the through hole. The first pressure transmission pipe 2 is connected with the interior of the pressure measuring container 1 through the through hole, and the first pressure transmission pipe 2 is connected with the gas phase pipe 7 through the first pressure transmission pipe 21 and the second pressure transmission pipe 22. It should be noted that in this embodiment, the pressure measuring container 1 contains a low-temperature liquid, such as liquid nitrogen, liquid oxygen, etc., and there is a relatively high pressure in the pressure measuring container 1. When the gas in the pressure measuring container 1 enters the first pressure transmission pipe 2 through the valve, the relatively cold gas in the pressure measuring container 1 enters the normal first pressure transmission pipe 2. When the high-pressure and low-temperature gas enters the first pressure transmission pipe 2 at normal temperature and pressure, the gas will expand and cool down. Since the first pressure transmission pipe 2 is located at normal temperature, the temperature is higher than the temperature of the gas in the pressure measuring container 1, and the temperature of the gas is lower than the ambient temperature, so that a temperature difference is formed on the inner wall of the first pressure transmission pipe 2, resulting in condensation of the gas, and the condensed droplets or frost will remain in the first pressure transmission pipe 2.

[0053] The condensed droplets will slide along the bottom of the first guide portion 3 and enter the drain pipe 23. After entering the drain pipe 23, the droplets will flow into the pressure measuring container 1 again, thereby effectively avoiding the presence of liquid in the gas phase tube 7 to prevent subsequent inaccurate measurements. The refluxed liquid will continue to be put into the pressure measuring container 1 for use, and can also avoid the problem of evaporation or retention in the first pressure transmission tube 2 at room temperature under atmospheric pressure for a long time, affecting the measurement accuracy.

[0054] A first pressure-conducting pipe 21 is connected above the first flow-guiding portion 3. The first pressure-conducting pipe 21 is used to introduce the gas in the pressure-measuring container 1 into the second pressure-conducting pipe 22 and into the gas phase pipe 7. The arrangement of the first pressure-conducting pipe 21 and the second pressure-conducting pipe 22 can effectively isolate the gas phase pipe 7 from the pressure-measuring container 1 to avoid direct contact affecting the measurement accuracy. In the prior art, the gas phase pipe 7 is directly connected to the pressure-measuring container 1, but this connection method is not suitable for low-temperature and high-pressure containers. Another connection method in the prior art is to vertically connect the gas phase pipe 7 to the top of the pressure-measuring container 1. Although this method can also directly discharge the liquefied condensed liquid into the pressure-measuring container 1, the gas phase pipe 7 is still directly connected to the pressure-measuring container 1. As mentioned in this embodiment, the pressure-measuring container 1 is a low-temperature and high-pressure container. When the low-temperature and high-pressure gas enters the gas phase pipe 7 at normal temperature and pressure, pressure fluctuations will occur, thereby causing the problem of unstable measurement accuracy. In this embodiment, through the first pressure-conducting pipe 2. The first pressure-conducting pipe 21 and the second pressure-conducting pipe 22 effectively isolate the pressure measuring container 1 from the gas phase pipe 7 , which can allow gas to flow into the gas phase pipe 7 and prevent condensed medium from remaining in the gas phase pipe 7 .

[0055] Example 2

[0056] This embodiment is the same as the embodiment 1, and also uses a low-temperature high-pressure container and a differential pressure level gauge. This embodiment mainly describes the liquid phase tube 8 of the differential pressure level gauge.

[0057] like Figure 1 , Figure 2 and Figure 5 As shown, the gas-liquid drainage component also includes a second pressure transmission tube 4 and a bent tube 6. The second pressure transmission tube 4 is horizontally arranged, and the second pressure transmission tube 4 is connected to the liquid phase tube 8 through the bent tube 6. The bent tube 6 is bent at 90°, and the upper end of the bent tube 6 is connected to the second pressure transmission tube 4, and the lower end of the bent tube 6 is connected to the liquid phase tube 8.

[0058] like Figure 1 , Figure 2 and Figure 5 As shown, a second flow guide portion 5 is provided on the second pressure transmission tube 4 . The second flow guide portion 5 is provided close to the bending tube 6 . The second flow guide portion 5 is concave and converges in an arc shape toward the central axis of the second pressure transmission tube 4 .

[0059] like Figure 1 , Figure 2 and Figure 5 As shown, a fixed shaft is arranged in the vertical end of the bending tube 6, and a rotating drum 61 is rotatably connected to the fixed shaft. A plurality of guide plates are arranged on the rotating drum 61, and the plurality of guide plates are spirally arranged along the rotating drum 61. A spiral tube 62 is also connected between the bending tube 6 and the liquid phase tube 8, and the maximum height of the spiral tube 62 is always lower than the height of the second pressure transmission tube 4.

[0060] like Figure 1 , Figure 2 and Figure 5 As shown, a bypass pipe 63 is connected above the bending part of the bending pipe 6 , the bypass pipe 63 is connected to the gas phase pipe 7 , and a one-way valve 631 is provided on the bypass pipe 63 .

[0061] Specifically, the pressure measuring container 1 is provided with another through hole connected to the second pressure transmission tube 4, and a valve is also provided at the through hole. As mentioned in Example 1, the pressure measuring container 1 is a low-temperature and high-pressure container. When the valve is opened, the liquid medium in the pressure measuring container 1 enters the second pressure transmission tube 4. The liquid in the pressure measuring container 1 partially vaporizes to form bubbles due to entering the low-pressure area or being affected by external heat transfer. These bubbles will cause pressure fluctuations and affect the accuracy of liquid level measurement. At the same time, due to pressure changes in the pressure measuring container 1 and the first pressure transmission tube 2, pulsation will occur in the liquid phase tube 8, affecting the stability of the measurement.

[0062] The outer tube wall of the second pressure transmission tube 4 is provided with a second guide portion 5, and the second guide portion 5 shrinks toward the central axis of the second pressure transmission tube 4. The second guide portion 5 makes the middle of the second pressure transmission tube 4 narrower. When the liquid in the pressure measuring container 1 enters the second pressure transmission tube 4 and passes through the second guide portion 5, if bubbles are generated in the liquid in the pressure measuring container 1, they will pass through the narrow mouth of the second guide portion 5 and enter the bending tube 6, which can split the bubbles to a certain extent and gather them at the bending tube 6. The liquid continues to flow downward along the bending tube 6 and passes through the guide plate. The guide plate is conical. The downward gravity of the liquid can drive the conical guide plate to rotate along the fixed axis, thereby cutting the bubbles generated in the liquid. The bubbles entering the bending tube 6 along the second guide portion 5 and the bubbles split in the bending tube 6 are arranged according to the Gravity will remain on the top of the bending tube 6. A bypass tube 63 is provided on the top of the bending tube 6. The gas formed after the bubble bursts will enter the bypass tube 63. Preferably, a one-way valve 631 is provided on the bypass tube 63. The one-way valve 631 is a hydrophobic membrane one-way valve 631, which can allow the gas to pass through in one direction without backflow and can prevent the liquid from passing through the one-way valve 631. It can effectively prevent the liquid in the pressure measuring container 1 from entering the bypass tube 63 and then entering the gas phase tube 7 when the height of the bypass tube 63 is not enough. The gas entering the bypass tube 63 will enter the gas phase tube 7, and while the gas and liquid are separated, the gas therein can be refluxed into the gas phase tube 7 again, which can not only keep the air pressure and hydraulic pressure at both ends of the differential pressure transmitter 9 stable, but also discharge the excess gas in the liquid phase tube 8.

[0063] A spiral tube 62 is also connected between the bent tube 6 and the liquid phase tube 8. The design of the spiral tube 62 can allow the liquid to flow a longer distance to reach the liquid phase tube 8 in a limited space. The bubbles have been cleared at the bent tube 6. The spiral tube 62 is used to stably and slowly deliver the bubble-free liquid into the liquid phase tube 8 to avoid the low-temperature and high-pressure container directly entering the normal pressure pipeline, causing pressure instability and affecting the measurement accuracy.

[0064] Example 3

[0065] The first pressure transmission pipe 2 and the second pressure transmission pipe 4 are both provided with a heat insulation layer.

[0066] Specifically, both the first pressure transmission tube 2 and the second pressure transmission tube 4 are provided with a heat-insulating layer, which can prevent the gas in the pressure measuring container 1 from being overcooled for a long time when entering the first pressure transmission tube 2 or the liquid from entering the second pressure transmission tube 4, thereby preventing ice from forming at the inlet. The heat-insulating layer can be provided at the first pressure transmission tube 2, the second pressure transmission tube 4, or even the bypass tube 63.

[0067] Preferably, a heating device is also provided at the valve of the through hole of the pressure measuring container 1, and the heating device can heat the inlet of the first pressure transmission tube 2 and the second pressure transmission tube 4 to avoid freezing of the tube openings after the low-temperature liquid enters, and the heating method adopts intermittent heating; the gas phase tube 7 and the liquid phase tube 8 in this embodiment are not in direct contact with the pressure measuring container 1, therefore, the gas phase tube 7 and the liquid phase tube 8 are not easy to freeze relative to the tube openings of the first pressure transmission tube 2 and the second pressure transmission tube 4, thereby also avoiding direct heating of the gas phase tube 7 and the liquid phase tube 8, thereby affecting the density of the medium in the gas phase tube 7 and the liquid phase tube 8, causing the problem of inaccurate measurement.

[0068] Example 4

[0069] like Figure 4 As shown, this embodiment is a preferred arrangement of Embodiment 1, and the inner circumferential surface of the first pressure transmission tube 2 is inclined downward toward the pressure measuring container 1.

[0070] After the gas enters the first pressure transmission tube 2, it condenses to produce liquid droplets which can be directly discharged into the pressure measuring container 1 through the first pressure transmission tube 2. The bottom surface of the first pressure transmission tube 2 is tilted downward toward the measuring container, and the arrangement of the first flow guide portion 3 being located below the first pressure transmission tube 2 is cancelled, while the arrangement of the first flow guide portion 3 being located above the first pressure transmission tube 2 is retained. The condensed liquid droplets can slide along the inclined surface in the first pressure transmission tube 2 into the measuring container, and the gas continues to pass through the top of the first flow guide portion 3, the first pressure transmission tube 21 and the second pressure transmission tube 22 to enter the gas phase tube 7. Compared with the embodiment 1, this embodiment can save pipeline layout.

[0071] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A liquid level measuring instrument for a low-temperature and high-pressure container, characterized in that: include: A pressure measuring container (1), wherein a liquid is arranged in the pressure measuring container (1), and a distance exists between the liquid level and the inner top surface of the pressure measuring container (1); A liquid level meter, the liquid level meter comprising a gas phase tube (7), a liquid phase tube (8) and a differential pressure transmitter (9), one end of the gas phase tube (7) and the liquid phase tube (8) are both in communication with a pressure measuring container (1), one end of the gas phase tube (7) and the liquid phase tube (8) relative to the pressure measuring container (1) are respectively connected to two ends of the differential pressure transmitter (9), the connection end of the gas phase tube (7) is higher than the maximum liquid level of the liquid, and the liquid phase tube (8) is connected to the bottom of the pressure measuring container (1); A gas-liquid drainage component, the gas-liquid drainage component is respectively arranged at the connection ends of the gas phase pipe (7) and the liquid phase pipe (8) and the pressure measuring container (1), the gas-liquid drainage component comprises a first pressure transmission pipe (2), a first pressure transmission pipe (21), a second pressure transmission pipe (4) and a bending pipe (6), the second pressure transmission pipe (4) is arranged horizontally, the second pressure transmission pipe (4) is connected to the liquid phase pipe (8) through the bending pipe (6), the bending pipe (6) is bent at 90 degrees, the upper end of the bending pipe (6) is connected to the second pressure transmission pipe (4), and the lower end of the bending pipe (6) is connected to the liquid phase pipe (8); A fixed shaft is arranged in the vertical end of the bending tube (6), a rotating drum (61) is rotatably connected to the fixed shaft, a plurality of guide plates are arranged on the rotating drum (61), and the plurality of guide plates are arranged in a spiral shape along the rotating drum (61). A spiral tube (62) is also connected between the bending tube (6) and the liquid phase tube (8), and the maximum height of the spiral tube (62) is always lower than the height of the second pressure transmission tube (4); The gas phase tube (7) is used to introduce gas into the pressure measuring container (1), the liquid phase tube (8) is used to introduce liquid into the pressure measuring container (1), the differential pressure transmitter (9) is used to measure the liquid level in the pressure measuring container (1) by means of the pressure of the gas or liquid in the gas phase tube (7) and the liquid phase tube (8), and the gas-liquid drainage component is used to separate gas and liquid in the gas phase tube (7) or the liquid phase tube (8).

2. The liquid level measuring instrument for a cryogenic and high-pressure container according to claim 1, characterized in that: The first pressure transmission pipe (2) is arranged horizontally, the first pressure transmission pipe (2) is connected to the first pressure transmission pipe (21), the first pressure transmission pipe (21) is connected to the gas phase pipe (7), and the first pressure transmission pipe (21) is located above the first pressure transmission pipe (2).

3. The liquid level measuring instrument for a cryogenic and high-pressure container according to claim 2, characterized in that: One end of the gas phase pipe (7) close to the pressure measuring container (1) is connected to a second pressure guiding pipe (22) towards the first pressure guiding pipe (21); the second pressure guiding pipe (22) is L-shaped and is located above the first pressure guiding pipe (21).

4. The liquid level measuring instrument for a cryogenic and high pressure container according to claim 2, characterized in that: A first flow guide portion (3) is provided in the middle of the tube body of the first pressure transmission tube (2). The center of the first flow guide portion (3) is connected to the first pressure transmission tube (2). The diameter of the first flow guide portion (3) located above the first pressure transmission tube (2) gradually decreases upward, and the diameter of the first flow guide portion (3) located below the first pressure transmission tube (2) gradually decreases downward. The first pressure transmission tube (21) is connected to the upper part of the first flow guide portion (3). The lower part of the first flow guide portion (3) is connected to a drain pipe (23). The drain pipe (23) is connected to the pressure measuring container (1). The outlet of the drain pipe (23) is higher than the maximum liquid level of the pressure measuring container (1).

5. The liquid level measuring instrument for a cryogenic and high-pressure container according to claim 2, characterized in that: The inner peripheral surface of the first pressure transmission tube (2) is inclined downward toward the pressure measuring container (1).

6. The liquid level measuring instrument for a cryogenic and high pressure container according to claim 4, characterized in that: The second pressure transmission tube (4) is provided with a second flow guide portion (5), the second flow guide portion (5) being arranged close to the bent tube (6), and the second flow guide portion (5) being concave and contracted in an arc shape towards the central axis of the second pressure transmission tube (4).

7. The liquid level measuring instrument for a cryogenic and high pressure container according to claim 4, characterized in that: A bypass pipe (63) is connected above the bent portion of the bent pipe (6), the bypass pipe (63) is connected to the gas phase pipe (7), and a one-way valve (631) is provided on the bypass pipe (63).

8. The liquid level measuring instrument for a cryogenic and high pressure container according to claim 4, characterized in that: The first pressure transmission pipe (2) and the second pressure transmission pipe (4) are both provided with a thermal insulation layer.

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