A contact type liquid level meter for liquid metal and its preparation method and container

Abstract

The present disclosure provides a contact type liquid level meter for measuring the liquid level of liquid metal in a container, the liquid level meter comprising: a base (113) and a probe (114), wherein the probe (114) is formed into a long column having a first end and a second end; the first end is fixed on the base (113) and is used to conduct with the first electrode, and the second end extends downward to the inside of the container to conduct with the second electrode through the liquid metal; at least part of the side surface of the probe (114) has an insulating coating. The present disclosure prepares an insulating coating on the probe surface and the inner wall of the base, on the one hand, the corrosion resistance of the insulating coating can be utilized to protect the probe; on the other hand, after the liquid metal is precipitated on the side surface of the probe, due to the insulating property of the insulating coating, the liquid level meter will not be accidentally touched, so that the measurement data is more accurate, and the connection and short circuit problems caused by the solidification of metal vapor are solved.

Description

Technical Field

[0001] The present disclosure relates to the field of liquid level measurement, and in particular to a contact type liquid level meter for liquid metal, a preparation method thereof, and a container thereof. Background Art

[0002] There are two existing methods for measuring metal liquid levels: non-contact and contact. The contact level gauge is based on the conductivity of liquid metal. The sensing component is inserted into the liquid metal. When the sensing component contacts the metal liquid surface, the circuit is turned on. The existing contact level gauge is in a high-temperature operation process for a long time in a liquid metal environment. The liquid metal vapor evaporates and solidifies on the surface of the level gauge measuring component. This deposit is permanently deposited on the outer surface, which destroys the insulation and causes a local short circuit, making the level gauge measurement invalid, introducing errors that are difficult to estimate, and is not conducive to subsequent maintenance and processing. Therefore, the current biggest obstacle to its widespread use is the false alarm of the level gauge due to the precipitation of metal vapor. Summary of the invention

[0003] The purpose of the present disclosure is to solve the problem of false alarm of liquid level gauge caused by precipitation of metal vapor.

[0004] In order to achieve the above-mentioned objectives, the first aspect of the present disclosure provides a contact-type liquid level meter for measuring the liquid level of liquid metal in a container, the liquid level meter comprising: a base for being fixed on the top of the shell of the container; a probe formed into a long column having a first end and a second end; the first end is fixed on the base and is used to conduct with a first electrode, and the second end extends downward to the interior of the container for conducting with a second electrode through liquid metal; at least part of the side surface of the probe has an insulating layer.

[0005] Optionally, the material of the base and / or the probe is independently selected from one or more of carbon steel, heat-resistant steel, stainless steel, high-temperature alloy, refractory metal or a combination thereof; the insulating coating contains Al2O3 and optional TiO2.

[0006] Optionally, the thickness of the insulating coating is 5-500 μm.

[0007] Optionally, the probe is a cylinder, and the insulating coating covers the side surface of the cylinder.

[0008] Optionally, the base includes a cylindrical base, an insulating filling block and a pressure cover, the cylindrical base has a vertical stepped through hole, and the stepped through hole includes a large cylindrical hole and a small cylindrical hole from top to bottom; the filling block and the pressure cover are arranged in the large cylindrical hole from bottom to top; the inner side wall of the large cylindrical hole has an internal thread, and the pressure cover has a threaded connection part matching the large cylindrical hole; the pressure cover has a through hole, and the apertures of the through hole and the small cylindrical hole respectively match the diameter of the probe.

[0009] The second aspect of the present disclosure adopts the contact type liquid level gauge described in the first aspect of the present disclosure to prepare a method for a contact type liquid level gauge for liquid metal, the method comprising: sandblasting the probe substrate; preheating the sandblasted probe substrate, and then forming the insulating coating on at least a portion of the side surface of the preheated probe substrate; the method for forming the insulating coating comprises: one or more of spraying, physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, cladding, atomic layer deposition, wire arc coating, electrophoretic deposition, electroless coating, 3D printing and sol-gel method; the spraying is selected from one or more of plasma spraying, supersonic flame spraying, microbeam plasma spraying and arc spraying; the method for forming the insulating coating is preferably spraying, and more preferably plasma spraying.

[0010] Optionally, the method further comprises preparing an insulating coating on an inner wall of the stepped through hole of the base.

[0011] Optionally, the conditions for the sandblasting treatment include: a sandblasting pressure of 0.2 to 0.4 MPa, a sandblasting distance of 50 to 100 mm, and a spray gun moving speed of 90 to 150 mm / s; the sandblasting material is selected from one or more of white corundum, brown corundum and zirconium corundum; the preheating treatment includes: preheating with a plasma flame without powder feeding; the preheating temperature is 300 to 400°C; the conditions for the preheating treatment include: a plasma spray gun current of 200 to 500 A, a nitrogen flow rate of 30 to 45 L / min, The flow rate of hydrogen is 2 to 8 L / min, the spray distance is 50 to 100 mm, and the moving speed of the plasma spray gun is 300 to 500 mm / s; the conditions for the plasma spraying treatment include: the plasma spray gun current is 300 to 700 A, the nitrogen flow rate is 30 to 50 L / min, the hydrogen flow rate is 5 to 10 L / min, the powder particle size is 5 to 40 μm, the powder feeding rate is 30 to 50 g / min, the spray distance is 70 to 120 mm, and the moving speed of the spray gun is 350 to 550 mm / s.

[0012] In a third aspect of the present disclosure, a contact-type liquid level gauge is manufactured using the method described in the second aspect of the present disclosure.

[0013] The fourth aspect of the present disclosure provides a container for storing liquid metal, the container comprising a liquid metal container shell, a power supply and the contact type liquid level meter described in the first aspect of the present disclosure or the third aspect of the present disclosure; the base is fixed on the top of the liquid metal container shell.

[0014] Through the above technical solution, the present invention sprays an insulating coating on the probe surface. On the one hand, the corrosion resistance of the insulating coating can be used to protect the probe and increase the service life of the liquid level meter. On the other hand, after the liquid metal is precipitated on the side surface of the probe, the liquid level meter will not produce false connection touch due to the insulation of the insulating coating, making the measurement data more accurate. The design of the liquid level meter solves the connection and short circuit problems caused by the solidification of metal vapor.

[0015] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0017] Figure 1 The diagram is a schematic structural diagram of a contact type liquid level meter disclosed in the present invention.

[0018] Figure 2 This is a cross-sectional view of a contact type liquid level gauge disclosed in the present invention after heat shock resistance testing.

[0019] Figure 3 The present invention discloses a contact type liquid level gauge and a schematic diagram of a sodium storage tank.

[0020] Description of Reference Numerals

[0021] 111 Press the upper cover 112 Filling block

[0022] 113 Base 114 Probe

[0023] 211 High level gauge 212 Low level gauge

[0024] 213 Thermocouple tube 214 Interface tube

[0025] 215 Flange cover 216 Liquid metal container shell. DETAILED DESCRIPTION

[0026] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0027] In the present disclosure, unless otherwise stated, directional words such as "inside" and "outside" refer to the inside and outside of the corresponding component contour; "upper" and "lower" refer to the upper and lower parts of the device when it is in use, for example, Figure 1 The "large cylindrical hole" and "small cylindrical hole" are distinguished by the large and small diameters of the stepped through hole of the base 113; the "threaded connection portion" refers to the portion containing matching threads in the contact portion between the pressure cap 111 and the inner surface of the cylindrical hole of the base 113; "matching" means that the diameters of the through holes in the probe 114 and the base 113 and the various components included therein are equal, and the probe is inserted into the through hole without a gap; the "inner wall" refers to the entire inner surface of the contour of the base 113, including the large cylindrical hole, the small cylindrical hole, the connection portion between the large cylindrical hole and the small cylindrical hole, and the threaded portion of the base 113.

[0028] A first aspect of the present disclosure provides a contact type liquid level meter for measuring the liquid level of liquid metal in a container, wherein the liquid level meter comprises: a base 113 for being fixed on the top of the shell of the container; and a probe 114 formed into a long column having a first end and a second end; the first end is fixed on the base 113 and is used to conduct with the first electrode, and the second end extends downward to the interior of the container for conducting with the second electrode through the liquid metal; at least part of the side surface of the probe 114 has an insulating coating.

[0029] The present invention sprays an insulating coating on the surface of the probe 114 and the inner wall of the base 113. On the one hand, the corrosion resistance of the insulating coating can be used to protect the probe 114 and increase the service life of the liquid level meter. On the other hand, after the liquid metal is precipitated on the side surface of the probe 114, the insulating property of the insulating coating prevents the liquid level meter from forming a path, making the measurement data more accurate. The design of the liquid level meter solves the problems of connectivity and short circuit caused by the solidification of metal vapor.

[0030] According to the present disclosure, as a preferred embodiment, the material of the base 113 and / or the probe 114 is independently selected from one or more of carbon steel, heat-resistant steel, stainless steel, high-temperature alloy, refractory metal or a combination thereof; the insulating layer comprises Al2O3 and optional TiO2, preferably Al2O3. Spraying process (plasma spraying, supersonic flame spraying, micro-beam plasma spraying, arc spraying, etc.), physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, cladding, atomic layer deposition, wire arc coating, electrophoretic deposition, electroless coating, 3D printing, sol-gel method or other suitable methods can be used to prepare the insulating layer on the inner wall of the base (inner wall of the tube) and (or) the surface of the probe component. As a preferred method for preparing the insulating layer, plasma spraying is preferred.

[0031] In this preferred embodiment, the aluminum oxide insulating coating can meet the requirements of high insulation performance of instruments and equipment under extreme conditions due to its advantages of acid and alkali corrosion resistance, lead and bismuth corrosion resistance, wear resistance, radiation resistance, and high insulation strength. The hardness of the Al2O3+TiO2 insulating coating is slightly lower than that of the Al2O3 coating, and Al2O3 is preferred to obtain higher insulation strength.

[0032] According to the present disclosure, as a preferred embodiment, the thickness of the insulating layer is 5 to 500 μm.

[0033] In the preferred embodiment, the appropriate thickness of the insulation coating sprayed is conducive to the insulation coating exhibiting good insulation properties.

[0034] According to the present disclosure, as a preferred embodiment, the probe 114 is a cylinder, and the insulating coating covers the side surface of the cylinder.

[0035] In this preferred embodiment, the side surface of the probe 114 is covered with an insulating coating, while the upper and lower ends are not sprayed with an insulating coating. On the one hand, the part of the probe 114 that contacts the liquid metal and the probe 114 substrate exposed on the lower surface are connected to the liquid metal without affecting its conductivity.

[0036] According to the present disclosure, as a preferred embodiment, the base 113 includes a cylindrical base, an insulating filling block 112 and a gland 111, wherein the cylindrical base has a vertical stepped through hole, and the stepped through hole includes a large cylindrical hole and a small cylindrical hole from top to bottom; the filling block 112 and the gland 111 are arranged in the large cylindrical hole from bottom to top; the inner side wall of the large cylindrical hole has an internal thread, and the gland 111 has a threaded connection part matching the large cylindrical hole; the gland 111 has a through hole, and the apertures of the through hole and the small cylindrical hole respectively match the diameter of the probe 114; the inner wall of the stepped through hole is covered with an insulating coating. The material of the gland 111 is selected from one or more of carbon steel, heat-resistant steel, stainless steel, high-temperature alloy, refractory metal or a combination thereof; the material of the insulating filling block 112 is polytetrafluoroethylene.

[0037] In this preferred embodiment, the inner side wall of the stepped through hole of the base 113 is covered with an insulating coating, so that after the probe 114 is combined with the base 113, metal will not be precipitated on the inner wall of the base 113. At the same time, the thread design of the insulating filling block 112 and the inner wall can make the components of the level meter more tightly combined. The filling block 112 is made of polytetrafluoroethylene material. Since this material has strong acid and alkali resistance and high temperature resistance, its use in the level meter can make the components of the entire level meter more tightly combined.

[0038] The second aspect of the present disclosure adopts the contact level gauge described in the first aspect of the present disclosure to prepare a method for a contact level gauge for liquid metal, the method comprising: sandblasting a probe substrate; preheating the sandblasted probe substrate, and then forming an insulating coating on at least a portion of the side surface of the preheated probe substrate; the method for forming the insulating coating comprises: one or more of spraying, physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, cladding, atomic layer deposition, wire arc coating, electrophoretic deposition, electroless coating, 3D printing and sol-gel method; spraying is selected from one or more of plasma spraying, supersonic flame spraying, microbeam plasma spraying and arc spraying; the method for forming the insulating coating is preferably spraying, and more preferably plasma spraying.

[0039] According to the present disclosure, as a preferred embodiment, the method further includes preparing an insulating layer on the inner wall of the stepped through hole of the base 113. In this preferred embodiment, preparing an insulating layer on the inner wall of the stepped through hole of the base 113 can prevent the possibility of cold adhesion of liquid metal leading to connectivity.

[0040] According to the present disclosure, as a preferred embodiment, the sandblasting conditions include: the sandblasting pressure is 0.2-0.4 MPa, the sandblasting distance is 50-100 mm, and the spray gun moving speed is 90-150 mm / s; the sandblasting material is selected from one or more of white corundum, brown corundum and zirconium corundum.

[0041] According to the present disclosure, as a preferred embodiment, the preheating treatment includes placing the base 113 and / or the probe 114 substrate into a sample fixture, and preheating the substrate to 300-400°C using a plasma flame flow without powder feeding; the preheating treatment conditions include: a plasma spray gun current of 200-500A, a nitrogen flow rate of 30-45L / min, a hydrogen flow rate of 2-8L / min, a spray distance of 50-100mm, and a moving speed of the plasma spray gun of 300-500mm / s.

[0042] According to the present disclosure, as a preferred embodiment, the conditions for plasma spraying treatment include: plasma spray gun current of 300-700A, nitrogen flow rate of 30-50L / min, hydrogen flow rate of 5-10L / min, powder particle size of 5-40μm, powder feeding rate of 30-50g / min, spraying distance of 70-120mm, and spray gun moving speed of 350-550mm / s.

[0043] In this preferred embodiment, the substrate to be sprayed is subjected to heat treatment, which increases the contact temperature between the coating and the substrate surface, reduces the stress caused by the different thermal expansion coefficients of the coating and the substrate material, and improves the bonding strength between the coating and the substrate. In the spraying process, the powder fed into the flame flow melts more fully, reduces the proportion of unmelted particles in the coating, and improves the smoothness of the coating.

[0044] In a third aspect of the present disclosure, a contact-type liquid level gauge is manufactured using the method described in the second aspect of the present disclosure.

[0045] The fourth aspect of the present disclosure provides a container for storing liquid metal, the container comprising a liquid metal container shell 216, a power supply and a contact type liquid level meter as described in the first aspect of the present disclosure or the third aspect of the present disclosure; the base 113 is fixed on the top of the liquid metal container shell 216.

[0046] In one embodiment, the container of liquid metal includes a high liquid level gauge 211, a low liquid level gauge 212, a thermocouple tube 213, an interface tube 214, a flange cover 215 and a liquid metal container shell 216; the liquid metal is a common liquid metal and / or a mixed liquid metal, for example, Na, K, Na-K alloy, Li, Pb, PbBi alloy, PbLi alloy, Cs-K, K-Ru, Bi-Cd-In-Pb and Sb-Sn and other conductive low-melting-point metals and their alloys.

[0047] The present disclosure is further illustrated below by way of examples, but the present disclosure is not limited thereby.

[0048] Unless otherwise specified, the materials, reagents, instruments and equipment used in the embodiments of the present disclosure can be obtained from commercial sources.

[0049] Example 1

[0050] Degrease and remove oil from the probe base, and perform sandblasting on the surface. Use brown corundum with a particle size of 60#, a sandblasting pressure of 0.2MPa, a sandblasting distance of 90mm, and a spray gun moving speed of 120mm / s. Use compressed air to blow away any remaining sand or dust.

[0051] The base and the probe substrate were placed in the sample fixture and preheated under the conditions of a plasma spray gun current of 500A, nitrogen of 38L / min, hydrogen of 5L / min, a spray distance of 100mm, and a spray gun moving speed of 500mm / s.

[0052] After preheating the base and the probe substrate to 350°C, the side surface of the probe and the inner wall of the base were sprayed. The plasma spray gun current was 500A, nitrogen was 40L / min, hydrogen was 10L / min, the powder feeding rate was 35g / min, the powder particle diameter was 20μm, the spraying distance was 100mm, and the spray gun moving speed was 500mm / s.

[0053] After spraying, cool down to 15-35℃ in the furnace, take out and assemble into a level gauge.

[0054] The base has a vertical stepped through hole, which includes a large cylindrical hole and a small cylindrical hole from top to bottom, and the filling block and the pressure cover are arranged in the large cylindrical hole from bottom to top; the inner wall of the large cylindrical hole has an internal thread, and the pressure cover has a threaded connection part matching the large cylindrical hole; the probe with an insulating coating on the side surface extends from top to bottom along the through hole to the inside of the container, the first end of the probe is fixed on the base and is used to conduct with the first electrode, and the second end extends downward to the inside of the container.

[0055] The base is made of 304 stainless steel, the gland is made of 304 stainless steel, and the thickness of the insulation film is 50μm.

[0056] Example 2

[0057] The preparation method of the contact type liquid level gauge is the same as that of Example 1, except that the probe substrate is refractory metal TZM (Mo-0.5Ti-0.08Zr), zirconium corundum with a particle size of 80# is used, and the sandblasting pressure is 0.3MPa.

[0058] The base and the probe substrate were placed in the sample fixture and preheated under the conditions of a plasma spray gun current of 400A, nitrogen of 37L / min, hydrogen of 4L / min, a spray distance of 100mm, and a spray gun moving speed of 400mm / s.

[0059] After preheating the base and the probe substrate to 400°C, the side surface of the probe and the inner wall of the base were sprayed. The plasma spray gun current was 550A, nitrogen was 42L / min, hydrogen was 9L / min, the powder feeding rate was 40g / min, the powder particle diameter was 10μm, and the spraying distance was 105mm.

[0060] The thickness of the insulating film is 140 μm.

[0061] Example 3

[0062] The preparation method of the contact type liquid level gauge is the same as that of Example 1, except that the probe substrate is high temperature nickel-based alloy K465, white corundum with a particle size of 60# is used, the sandblasting pressure is 0.4MPa, and the sandblasting distance is 100mm.

[0063] Place the base and probe matrix into the sample holder, with nitrogen at 40 L / min and hydrogen at 4 L / min.

[0064] After preheating the base and probe substrate to 300°C, the plasma spray gun current was 520A, nitrogen 45L / min, hydrogen 7L / min, powder feeding rate 45g / min, powder particle diameter 30μm, spraying distance 95mm, and spray gun moving speed 90-150mm / s.

[0065] The base material is 316 stainless steel, the pressure cover material is 316 stainless steel, and the insulation film thickness is 130μm.

[0066] Example 4

[0067] The preparation method of the contact type liquid level gauge is the same as that of Example 1, except that 80# zirconium corundum is used and the sandblasting pressure is 0.35 MPa.

[0068] Place the base and probe matrix into the sample holder, and set the plasma spray gun current to 400A and the spray gun moving speed to 400mm / s.

[0069] After preheating the base and the probe substrate to 320°C, the side surface of the probe and the inner wall of the base were sprayed. The plasma spray gun current was 530A, nitrogen was 44L / min, hydrogen was 8L / min, the powder feeding rate was 42g / min, the powder particle diameter was 15μm, the spraying distance was 95mm, and the spray gun moving speed was 490mm / s.

[0070] The base material is 316 stainless steel, the pressure cover material is 316 stainless steel, and the insulation film thickness is 160μm.

[0071] Example 5

[0072] The production of the liquid level gauge probe and the contact type liquid level gauge is the same as that in Example 1, except that the probe substrate is made of high temperature nickel-based alloy K465 and uses 80# zirconium corundum, the sandblasting pressure is 0.35MPa, the sandblasting distance is 100mm, and compressed air is used to blow away any remaining sand or dust.

[0073] Place the base and probe substrate into the sample fixture, with nitrogen at 45 L / min, hydrogen at 6 L / min, and a spraying distance of 80 mm.

[0074] After preheating the base and the probe substrate to 400°C, the side surface of the probe and the inner wall of the base were sprayed. The plasma spray gun current was 450A, the hydrogen was 5L / min, and the powder particle diameter was 10μm.

[0075] The thickness of the insulating film is 150 μm.

[0076] Test Example 1 Thermal Shock Resistance Test

[0077] The aluminum oxide insulating coatings prepared in Examples 1 to 5 were selected and subjected to a thermal cycle test in liquid metal (lead-bismuth alloy) for 120 times at a heating and cooling rate of 100°C / s and a temperature range of 400 to 600°C. Figure 2 As shown, the coating substrate interface is well bonded without cracks or peeling, which indicates that the aluminum oxide coating in this embodiment has good thermal shock resistance.

[0078] Test Example 2: Use test of liquid level meter in liquid metal sodium storage tank

[0079] The probe with insulating coating is assembled into a liquid level gauge and extended into the liquid metal sodium storage tank, such as Figure 3 The sodium storage tank shown includes a high level gauge 211 and a low level gauge 212, which are used to indicate that the sodium level is within the available range. The high level gauge 211 and the low level gauge 212 have the same structure, except that the probe lengths are different. Figure 3 As shown. The level gauge probe is made of 304 stainless steel. After the level gauge probe is machined, the area 100mm below the end face of the level gauge probe is plasma sprayed with Al2O3+TiO2 composite powder insulation coating. During the operation of the circuit, no false alarm of connection occurs.

[0080] Test Example 3: Test of the use of liquid level meter in the lead-bismuth dynamic loop expansion tank

[0081] When the liquid metal container is a lead-bismuth dynamic loop expansion tank, two common contact-type liquid level gauges are installed in the lead-bismuth dynamic loop expansion tank to indicate the low and high liquid level states of the liquid lead-bismuth alloy in the expansion tank. When the liquid lead-bismuth alloy rises to a high liquid level and then falls back, the lead-bismuth alloy residues adhere to the liquid level gauge, causing the liquid level gauge to communicate with the wall surface and send out an erroneous liquid level indication signal. After replacing the liquid level gauge in the lead-bismuth dynamic loop expansion tank with the liquid level gauge disclosed in the present invention, no erroneous liquid level indication signal appears during the operation of the loop.

[0082] The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0083] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0084] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A contact type liquid level gauge for measuring the liquid level of liquid metal in a container, characterized in that: The liquid level meter comprises: A base (113) used for being fixed on the top of the shell of the container; The probe (114) is formed into a long column having a first end and a second end; the first end is fixed to the base (113) and is used to conduct with the first electrode, and the second end extends downward to the inside of the container and is used to conduct with the second electrode through liquid metal; At least part of the side surface of the probe (114) has an insulating coating; The material of the base (113) and / or the probe (114) is independently selected from one or more of carbon steel, heat-resistant steel, stainless steel, high-temperature alloy, refractory metal or a combination thereof; The insulating coating comprises Al2O3 and TiO2; The base (113) comprises a cylindrical base, an insulating filling block (112) and a gland (111); the cylindrical base has a stepped through hole in a vertical direction, and the stepped through hole comprises a large cylindrical hole and a small cylindrical hole in sequence from top to bottom; the filling block (112) and the gland (111) are arranged in sequence in the large cylindrical hole from bottom to top; the inner side wall of the large cylindrical hole has an internal thread, and the gland (111) has a threaded connection portion matching the large cylindrical hole; the gland (111) has a through hole, and the apertures of the through hole and the small cylindrical hole respectively match the diameter of the probe (114).

2. The contact type liquid level gauge according to claim 1, characterized in that: The thickness of the insulating coating is 5-500 μm.

3. The contact type liquid level gauge according to claim 1, characterized in that: The probe (114) is a cylinder, and the insulating coating covers the side surface of the cylinder.

4. A method for preparing the contact type liquid level gauge according to any one of claims 1 to 3, characterized in that: The method comprises: sandblasting the probe substrate; preheating the sandblasted probe substrate, and then forming the insulating coating on at least part of the side surface of the preheated probe substrate; The method of forming the insulating coating comprises: one or more of spraying, physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, cladding, atomic layer deposition, wire arc coating, electrophoretic deposition, electroless coating, 3D printing and sol-gel method; The spraying is selected from one or more of plasma spraying, supersonic flame spraying, micro-beam plasma spraying and arc spraying.

5. The method according to claim 4, characterized in that The insulating coating is formed by spraying.

6. The method according to claim 4, characterized in that The method also includes preparing an insulating coating on the inner wall of the stepped through hole of the base (113).

7. The method according to claim 4, characterized in that The conditions of the sandblasting treatment include: the sandblasting pressure is 0.2-0.4 MPa, the sandblasting distance is 50-100 mm, and the spray gun moving speed is 90-150 mm / s; The sandblasting material is selected from one or more of white corundum, brown corundum and zirconium corundum; the preheating treatment includes: preheating with a plasma flame without powder feeding; the preheating temperature is 300-400°C; The conditions of the preheat treatment include: plasma spray gun current of 200-500A, nitrogen flow rate of 30-45L / min, hydrogen flow rate of 2-8L / min, spray distance of 50-100mm, and moving speed of the plasma spray gun of 300-500mm / s; The conditions of the plasma spraying treatment include: plasma spray gun current of 300~700A, nitrogen flow rate of 30~50L / min, hydrogen flow rate of 5~10L / min, powder particle size of 5~40μm, powder feeding rate of 30~50g / min, spraying distance of 70~120mm, and spray gun moving speed of 350~550mm / s.

8. A container for storing liquid metal, characterized in that: The container comprises a liquid metal container shell (216), a power supply, and a contact type liquid level meter as described in any one of claims 1 to 3; the base (113) is fixed on the top of the liquid metal container shell (216).

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