A process method for measuring the liquid level of a cryogenic pressure vessel

Abstract

The application discloses a liquid level measuring process method for a cryogenic pressure container and belongs to the technical field of chemical pressure containers, in particular to a liquid level measuring process method for a cryogenic pressure container, which comprises the following specific steps: winding a copper wire on a liquid level meter liquid phase pipe located between an outer container and an inner container, fixing two ends of the copper wire on the outer container, then, sleeving a hose provided with a thermal insulation sleeve on the outer wall and an electric heating wire on the inner wall on the liquid level meter liquid phase pipe located between the outer container and the inner container, after that, heating air in the hose through the electric heating wire, and after heating, performing heat exchange on the liquid level meter liquid phase pipe through the copper wire, the first heat exchange assembly is arranged to heat the liquid level meter liquid phase pipe located between the outer container and the inner container, and the second heat exchange assembly is arranged to heat a part of the liquid level meter liquid phase pipe outside the outer container, so that the liquid in the liquid level meter liquid phase pipe can be vaporized, and the measuring accuracy can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical pressure vessels, in particular to a liquid level measurement process method of a cryogenic pressure vessel. BACKGROUND

[0002] Liquid level measurement can be generally divided into direct measurement and indirect measurement. Direct measurement is the simplest and most intuitive measurement method, which uses the principle of communicating vessels to introduce the liquid in the container into an observation tube with a scale to read the liquid level height through the scale. Indirect measurement is to convert the liquid level signal into other related signals for measurement, such as pressure method, buoyancy method, electrical method, and thermal method. There are various types of liquid level height measurement devices, such as differential pressure liquid level meter, glass tube liquid level meter, floating ball liquid level meter, and rotary tube liquid level meter.

[0003] The most widely used liquid level measurement device in today's low-temperature pressure vessels is a double corrugated tube combined differential pressure liquid level meter. The differential pressure liquid level meter has two pressure ports, gas phase and liquid phase. The gas phase pressure port is located at the uppermost end of the container in the gas phase space and is subjected to the gas phase pressure; the liquid phase pressure port is located at the bottom of the tank, and the liquid phase pressure is subjected to the action of the liquid column static pressure in addition to the action of the gas phase pressure, and the difference between the liquid phase and the gas phase pressure is the liquid column static pressure. In general, the density of the measured medium and the acceleration of gravity are known, so the pressure difference measured by the differential pressure meter is proportional to the height H of the liquid, so the problem of measuring the height of the liquid is changed into the problem of measuring the differential pressure. The range of the combined differential pressure liquid level meter is usually kPa or millimeters of water column, and the liquid level height in the container can be known by converting the reading, and the volume and mass of the remaining medium can be converted.

[0004] Because there is a liquid level difference H between the bottom of the container and the liquid phase end of the liquid level meter, if there is a certain height of liquid in the liquid phase tube of the liquid level meter, the liquid phase end pressure of the liquid level meter will be less than the bottom end pressure of the container; if the liquid level height in the liquid phase tube of the liquid level meter is below the bottom end horizontal line of the container, the liquid phase end pressure of the liquid level meter will be higher than the bottom end pressure of the container.

[0005] The differential pressure liquid level meter measures the differential pressure, and because the outer diameter of the tank of the low-temperature tank truck is not more than 2500 mm, the differential pressure is relatively small, and even slight pressure fluctuations in the tank will be very large in terms of relative pressure difference. Therefore, it will cause the reading of the liquid level meter to fluctuate during loading and unloading, and the measurement will be inaccurate.

[0006] The above deficiencies will cause measurement errors of the liquid level meter. Because the environment is changing, if appropriate measures are not taken in the design when using the differential pressure liquid level meter, the reading will be inaccurate when the liquid level height of the low-temperature liquid in the container is unchanged. Therefore, a liquid level measurement process method of a cryogenic pressure vessel is invented. SUMMARY

[0007] In view of the above and / or existing problems in the liquid level measurement process of a cryogenic pressure vessel, the present application is proposed.

[0008] Therefore, the purpose of the present application is to provide a liquid level measurement process of a cryogenic pressure vessel, which can solve the above-mentioned existing problems.

[0009] To solve the above technical problems, according to one aspect of the present application, the present application provides the following technical solutions:

[0010] A liquid level measurement process of a cryogenic pressure vessel, comprising the following specific steps:

[0011] Step one: winding a copper wire on the liquid level meter liquid phase pipe located in the space between the outer container and the inner container, and fixing the two ends of the copper wire on the outer container, then, sleeving a hose with a thermal insulation sleeve on the outer wall and an electric heating wire on the inner wall on the liquid level meter liquid phase pipe located in the space between the outer container and the inner container, after that, heating the air in the hose through the electric heating wire, and after heating, heat exchanging the liquid level meter liquid phase pipe through the copper wire to vaporize the liquid in the liquid level meter liquid phase pipe;

[0012] Step two: making the liquid level meter liquid phase pipe located in the space between the outer container and the inner container spiral to prolong the length of the liquid level meter liquid phase pipe in the space between the outer container and the inner container, so as to realize sufficient vaporization of the liquid in the liquid level meter liquid phase pipe;

[0013] Step three: setting a second heat exchange component on the outer wall of the outer container to further heat exchange the liquid in the liquid level meter liquid phase pipe to completely vaporize it;

[0014] Step four: under the condition of ensuring that the inlet of the liquid level meter liquid phase pipe is not blocked, minimizing the communication aperture of the liquid level meter liquid phase pipe and the inner container.

[0015] As a preferred scheme of the liquid level measurement process of a cryogenic pressure vessel, wherein: the calculation process of heat exchange is:

[0016] Process one: calculating the heat conduction amount;

[0017] Process two: calculating the heat conduction amount of the copper wire and the heat conduction amount of other connecting pipes and epoxy glass steel supports together into the total heat leakage amount Q 总 kJ / h, calculating the daily heat leakage amount Q d kJ / d;

[0018] Process three: calculating the natural static daily evaporation rate of the liquid.

[0019] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: the formula for calculating heat conduction in process one is

[0020] Q=λ·A·∆T / L;

[0021] Wherein, λ is the thermal conductivity of copper wire W / m K, A is the cross-sectional area of copper wire m 2 , ∆T is the temperature difference between ambient temperature and inner tank temperature K, L is the length of winding copper wire m.

[0022] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: the formula for calculating the natural static daily evaporation rate of liquid in process three is

[0023] α=Q d ×100% / (ρ·γ·V e ) ;

[0024] Wherein, Q d is the daily heat loss kJ / d, ρ is the density of medium kg / m 3 , γ is the latent heat of vaporization of medium kJ / kg, V e is the effective volume m 3 .

[0025] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: further comprising a detection device, the detection device comprises:

[0026] Outer container;

[0027] Inner container, the inner cavity of the outer container is provided with an inner container;

[0028] Combined differential pressure liquid level meter, the combined differential pressure liquid level meter is arranged outside the outer container;

[0029] Liquid level meter gas phase pipe, connected to one end of the combined differential pressure liquid level meter, and one end of the liquid level meter gas phase pipe is connected to the top end of the inner container;

[0030] Liquid level meter liquid phase pipe, connected to one end of the combined differential pressure liquid level meter, and one end of the liquid level meter liquid phase pipe is connected to the bottom end of the inner container, and the liquid level meter liquid phase pipe in the space between the outer container and the inner container is arranged in a spiral shape;

[0031] First heat exchange component, and the first heat exchange component is arranged on the liquid level meter liquid phase pipe;

[0032] Second heat exchange component, and the second heat exchange component is arranged on the outer wall of the outer container.

[0033] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: the first heat exchange component includes

[0034] The hose is sleeved on the liquid level meter liquid phase pipe of the space of outer container and inner container.

[0035] The heat preservation sleeve is arranged on the outer surface of the hose.

[0036] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: the first heat exchange component further includes

[0037] The electric heating wire is spirally arranged on the inner surface of the hose.

[0038] The copper wire is wound on the liquid level meter liquid phase pipe, and the copper wire is located in the inner cavity of the hose.

[0039] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: the second heat exchange component includes

[0040] The heating cover is fixedly installed on the outer wall of the outer container, and the inner cavity of the heating cover is provided with the liquid level meter liquid phase pipe.

[0041] The heat preservation layer is arranged on the outer surface of the heating cover.

[0042] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: the second heat exchange component further includes

[0043] The hollow tube is fixedly installed on the side wall of the heating cover.

[0044] The fan is fixedly installed on the inner wall of one end of the hollow tube.

[0045] The support rod is fixedly installed on the inner wall of the other end of the hollow tube.

[0046] The U-shaped heating pipe is fixedly installed between the two groups of support rods.

[0047] The first electromagnetic valve is arranged on the hollow tube.

[0048] As a kind of preferred scheme of the liquid level measurement process method of the cryogenic pressure vessel described in the application, wherein: the second heat exchange component further includes

[0049] The breather pipe is fixedly installed on the other side wall of the heating cover.

[0050] A second electromagnetic valve is arranged on the air pipe.

[0051] Compared with the prior art, the present application has the following advantages:

[0052] The first heat exchange assembly is arranged to heat the liquid level meter liquid phase pipe in the space between the outer container and the inner container, and the second heat exchange assembly is arranged to heat a part of the liquid level meter liquid phase pipe outside the outer container, so that the liquid in the liquid level meter liquid phase pipe can be vaporized, and the measurement accuracy can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 It is a structural front view of the present application.

[0054] Figure 2 It is a structural front view of the present application. Figure 1 It is an enlarged schematic view of structure A in the present application.

[0055] Figure 3 It is a schematic view of the copper wire winding structure of the present application.

[0056] Figure 4 It is a partial structural sectional view of the first heat exchange assembly of the present application.

[0057] Figure 5 It is a side view of the first heat exchange assembly of the present application.

[0058] In the figure: outer container 10, inner container 20, combined differential pressure liquid level meter 30, liquid level meter gas phase pipe 40, liquid level meter liquid phase pipe 50, heat preservation sleeve 61, hose 62, electric heating wire 63, copper wire 64, heating cover 71, heat preservation layer 72, hollow pipe 73, fan 74, support rod 75, U-shaped heating pipe 76, first electromagnetic valve 77, air pipe 78, second electromagnetic valve 79. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical scheme and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0060] The present application provides a liquid level measurement process method of a cryogenic pressure vessel, please refer to Figures 1-5 , which includes the following specific steps:

[0061] Step one: winding copper wire 64 on the liquid level meter liquid phase pipe 50 located in the space between the outer container 10 and the inner container 20, and fixing the two ends of the copper wire 64 on the outer container 10, then, sleeving the hose 62 provided with the heat preservation sleeve 61 on the outer wall and the electric heating wire 63 on the inner wall on the liquid level meter liquid phase pipe 50 located in the space between the outer container 10 and the inner container 20, after that, the air in the hose 62 can be heated by the electric heating wire 63, and after heating, the liquid in the liquid level meter liquid phase pipe 50 can be heat exchanged by the copper wire 64, so that the liquid in the liquid level meter liquid phase pipe 50 is vaporized;

[0062] Step two: making the liquid level meter liquid phase pipe 50 located in the space between the outer container 10 and the inner container 20 spiral, so as to prolong the length of the liquid level meter liquid phase pipe 50 in the space between the outer container 10 and the inner container 20, so as to realize sufficient vaporization of the liquid in the liquid level meter liquid phase pipe 50;

[0063] Step three: providing a second heat exchange assembly on the outer wall of the outer container 10, so as to further heat exchange the liquid in the liquid level meter liquid phase pipe 50, so that it can be completely vaporized;

[0064] Step four: under the condition of ensuring that the inlet of the liquid level meter liquid phase pipe 50 is not blocked, the communication aperture of the liquid level meter liquid phase pipe 50 and the inner container 20 is minimized.

[0065] The calculation process of heat exchange is as follows:

[0066] Process one: calculating the heat conduction amount;

[0067] The calculation formula of the heat conduction amount is as follows:

[0068] Q=λ·A·∆T / L;

[0069] Wherein, λ is the copper wire heat conduction coefficient W / m K, A is the copper wire cross-sectional area m 2 , ∆T is the temperature difference between the ambient temperature and the inner tank temperature K, and L is the length of the wound copper wire m;

[0070] Process two: the heat conduction amount of the copper wire and the heat conduction amount of other connecting pipes and epoxy glass steel supports are jointly calculated into the total heat leakage amount Q 总 kJ / h, the daily heat leakage amount Q d kJ / d;

[0071] Process three: calculating the liquid natural static daily evaporation rate;

[0072] The calculation formula of the liquid natural static daily evaporation rate is as follows:

[0073] α=Q d ×100% / (ρ·γ·V e ) ;

[0074] Wherein, Qd Q is the heat loss per day, kJ / d, p is the density of the medium, kg / m 3 , y is the latent heat of vaporization of the medium, kJ / kg, V e is the effective volume, m 3 .

[0075] The detection device further comprises an outer container 10, an inner container 20, a combined differential pressure liquid level meter 30, a liquid level meter gas phase pipe 40, a liquid level meter liquid phase pipe 50, a first heat exchange assembly, and a second heat exchange assembly.

[0076] The inner cavity of the outer container 10 is provided with the inner container 20, the combined differential pressure liquid level meter 30 is arranged on the outer side of the outer container 10, the liquid level meter gas phase pipe 40 is connected to one end of the combined differential pressure liquid level meter 30, one end of the liquid level meter gas phase pipe 40 is connected to the top end of the inner container 20, the liquid level meter liquid phase pipe 50 is connected to one end of the combined differential pressure liquid level meter 30, and one end of the liquid level meter liquid phase pipe 50 is connected to the bottom end of the inner container 20, the liquid level meter liquid phase pipe 50 in the space between the outer container 10 and the inner container 20 is arranged in a spiral shape, the first heat exchange assembly is arranged on the liquid level meter liquid phase pipe 50, and the second heat exchange assembly is arranged on the outer wall of the outer container 10.

[0077] The first heat exchange assembly comprises a heat preservation sleeve 61, a hose 62, an electric heating wire 63, and a copper wire 64.

[0078] The liquid level meter liquid phase pipe 50 in the space between the outer container 10 and the inner container 20 is sleeved with the hose 62, one end of the hose 62 is in contact with the inner container 20, the other end of the hose 62 extends into the second heat exchange assembly, the heat preservation sleeve 61 is arranged on the outer surface of the hose 62, the inner surface of the hose 62 is spirally provided with the electric heating wire 63, the copper wire 64 is wound on the liquid level meter liquid phase pipe 50, and the copper wire 64 is located in the inner cavity of the hose 62, and when the electric heating wire 63 works, the heat generated by the electric heating wire 63 flows into the second heat exchange assembly.

[0079] The second heat exchange assembly comprises a heating cover 71, a heat preservation layer 72, a hollow pipe 73, a fan 74, a support rod 75, a U-shaped heating pipe 76, a first electromagnetic valve 77, a breather pipe 78, and a second electromagnetic valve 79.

[0080] The heating cover 71 is fixedly installed on the outer wall of the outer container 10, and the inner cavity of the heating cover 71 is provided with the liquid level meter liquid phase pipe 50, the left end inner wall of the heating cover 71 is fixedly installed with the hose 62, the heat preservation layer 72 is arranged on the outer surface of the heating cover 71, the hollow pipe 73 is fixedly installed on the side wall of the heating cover 71, the fan 74 is fixedly installed on the one end inner wall of the hollow pipe 73, the other end inner wall of the hollow pipe 73 is fixedly installed with two groups of support rods 75, the U-shaped heating pipe 76 is fixedly installed between the two groups of support rods 75, the first electromagnetic valve 77 is arranged on the hollow pipe 73, and the air pipe 78 is fixedly installed on the other side wall of the heating cover 71, and the second electromagnetic valve 79 is arranged on the air pipe 78;

[0081] Working principle: start the first electromagnetic valve 77 and the second electromagnetic valve 79, at this time, the outside air is flowed into the hollow pipe 73 through the fan 74, when the air is flowed into the hollow pipe 73, the air is heated under the action of the U-shaped heating pipe 76, and the heated air is flowed to the liquid level meter liquid phase pipe 50, so that the liquid in the liquid level meter liquid phase pipe 50 is heated to be vaporized, wherein the air is flowed out from the air pipe 78.

[0082] Although the present application has been described with reference to the embodiments above in the foregoing description, it is to be understood that various modifications can be made without departing from the scope of the present application. More particularly, the features of the disclosed embodiments can be combined together in any manner, and the combinations of the features are not exhaustively described in the specification only for the purpose of saving space and resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for measuring the liquid level in a cryogenic pressure vessel, characterized in that, The specific steps are as follows: Step 1: Wrap copper wire (64) around the liquid phase tube (50) of the level gauge located in the space between the outer container (10) and the inner container (20), and fix the two ends of the copper wire (64) to the outer container (10). Then, put the hose (62) with the outer wall having an insulation sleeve (61) and the inner wall having an electric heating wire (63) on the liquid phase tube (50) of the level gauge located in the space between the outer container (10) and the inner container (20). After that, the air in the hose (62) can be heated by the electric heating wire (63). After heating, the liquid phase tube (50) of the level gauge can be heat exchanged by the copper wire (64) so ​​that the liquid in the liquid phase tube (50) of the level gauge vaporizes. Step 2: Make the liquid phase tube (50) of the level gauge located in the space between the outer container (10) and the inner container (20) spiral to extend the length of the liquid phase tube (50) of the level gauge in the space between the outer container (10) and the inner container (20) so as to enable the liquid in the liquid phase tube (50) of the level gauge to be fully vaporized; Step 3: A second heat exchange assembly is installed on the outer wall of the outer container (10) to further exchange heat with the liquid in the liquid phase tube (50) of the level gauge so that it can be completely vaporized; Step 4: While ensuring that the inlet of the liquid phase tube (50) of the level gauge is not blocked, minimize the connecting diameter between the liquid phase tube (50) of the level gauge and the inner container (20); The second heat exchange component includes: Heating cover (71), the heating cover (71) is fixedly installed on the outer wall of the outer container (10), and the inner cavity of the heating cover (71) is provided with a liquid level gauge liquid phase tube (50), and a flexible hose (62) is fixedly installed on the inner wall of the left end of the heating cover (71). A heat insulation layer (72) is provided on the outer surface of the heating cover (71); Hollow tube (73), which is fixedly installed on the side wall of heating cover (71); A fan (74) is fixedly installed on the inner wall of one end of a hollow tube (73); Support rod (75), two sets of support rods (75) are fixedly installed on the inner wall of the other end of the hollow tube (73); U-shaped heating tube (76), which is fixedly installed between two sets of support rods (75); The first solenoid valve (77) is mounted on the hollow tube (73); Vent pipe (78), the vent pipe (78) is fixedly installed on the other side wall of the heating cover (71); The second solenoid valve (79) is located on the vent pipe (78).

2. The method for measuring the liquid level in a cryogenic pressure vessel according to claim 1, characterized in that, The calculation process for the heat exchange is as follows: Step 1: Calculate heat conduction; Step 2: The calculated heat conduction of the copper wire, along with the heat conduction of the other pipes and epoxy fiberglass supports, is included in the total heat loss Q. 总 kJ / h, calculate daily heat loss Q d kJ / d; Step 3: Calculate the daily natural static evaporation rate of the liquid; The formula for calculating the heat conduction in process one is as follows: Q = λ·A·∆T / L; Where λ is the thermal conductivity of the copper wire (W / m K), and A is the cross-sectional area of ​​the copper wire (m²). 2 ∆T is the temperature difference between the ambient temperature and the inner tank temperature in K, and L is the length of the wound copper wire in m; The formula for calculating the daily natural static evaporation rate of liquid in process three is as follows: α=Q d ×100% / (ρ·γ·V e ); Among them, Q d The daily heat loss is kJ / d, and ρ is the density of the medium (kg / m³). 3 γ is the latent heat of vaporization of the medium (kJ / kg), V e For effective volume m 3 .

3. A liquid level measuring device for a cryogenic pressure vessel using the liquid level measuring method for a cryogenic pressure vessel according to any one of claims 1-2, characterized in that, include: Outer container (10); Inner container (20), the inner cavity of the outer container (10) is provided with inner container (20); A combined differential pressure level gauge (30) is provided on the outside of the outer container (10); A liquid level gauge vapor phase tube (40) is connected to one end of a combined differential pressure liquid level gauge (30), and one end of the liquid level gauge vapor phase tube (40) is connected to the top of the inner container (20). The liquid phase tube (50) of the level gauge is connected to one end of the combined differential pressure level gauge (30), and one end of the liquid phase tube (50) is connected to the bottom end of the inner container (20). The liquid phase tube (50) of the level gauge located in the space between the outer container (10) and the inner container (20) is arranged in a spiral shape. The first heat exchange component is located on the liquid phase tube (50) of the level gauge; The second heat exchange assembly is located on the outer wall of the outer container (10).

4. The liquid level measuring device for a cryogenic pressure vessel according to claim 3, characterized in that, The first heat exchange component includes: A hose (62) is fitted onto the liquid phase tube (50) of the level gauge located in the space between the outer container (10) and the inner container (20). Insulation sleeve (61) is provided on the outer surface of hose (62).

5. The liquid level measuring device for a cryogenic pressure vessel according to claim 4, characterized in that, The first heat exchange component further includes: Heating wire (63), the inner surface of the hose (62) is provided with heating wire (63) in a spiral shape; A copper wire (64) is wound around the liquid phase tube (50) of the level gauge and is located in the inner cavity of the flexible tube (62).

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