A high temperature liquid metal detection system

Abstract

The present disclosure belongs to the technical field of liquid metal detection instruments, and particularly relates to a high-temperature liquid metal detection system, which includes: a power supply, a warning device, a thermocouple temperature display, and a high-temperature liquid metal probe; wherein the high-temperature liquid metal probe, the power supply, and the warning device are connected in series through a wire; wherein the high-temperature liquid metal probe includes: a transition connector, an insulating member, a seal, and a structural member for supporting and fixing; wherein the seal and the insulating member are connected by a transition connector; wherein the insulating member is made of high-temperature resistant ceramic material. The high-temperature liquid metal probe of the present disclosure uses a ceramic tube, which is both a structural member and an insulating member, and the seal is made of a metal gasket; when other structural members and connectors are made of stainless steel, the maximum operating temperature can reach 650°C. If nickel-based alloys or refractory metal materials are used to make probes and threaded connectors, the temperature resistance can be further improved to 1000°C.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid metal detection instruments, and in particular relates to a detection system applied to high-temperature liquid metal. Background Art

[0002] In liquid metal devices, temperature and liquid level are important parameters related to operation and safety. Since liquid metal has a high operating temperature, especially liquid metal working fluids such as sodium, sodium-potassium alloy, lithium, and lead-bismuth alloy have active chemical properties and generally cannot come into direct contact with air, high sealing requirements are placed on the equipment. Therefore, the temperature and liquid level measurement in liquid metal equipment is more difficult than that of ordinary working fluids such as water.

[0003] The temperature of liquid metal is generally measured by thermocouple trap, that is, a blind tube is inserted into the working fluid, and then an armored thermocouple is placed for temperature measurement. This method can ensure the sealing of the device, and has higher accuracy than measuring on the wall outside the equipment, but it also requires a thermocouple trap tube to be reserved in the equipment pipe, which increases the complexity of the equipment.

[0004] The measurement of liquid metal level can be divided into two categories: continuous level gauge and level probe. Compared with the continuous level gauge with complex structure, high cost and special calibration, the level probe used to indicate the specific height level is more widely used. It can be used in many occasions such as safety level warning, filling operation stop signal, and flow calibration of liquid metal circuit storage tanks, measuring cylinders, expansion tanks and other equipment. When the temperature of liquid metal is higher than the melting point, liquid metal vapor will be generated and diffused above the liquid surface, which is easy to condense and deposit on the surface of the liquid level measurement components with lower temperature, causing corrosion to the probe material. In addition, after the metal working fluid is deposited, it is easy to cause adhesion between the insulating parts and the structural parts, resulting in false signal alarms and high maintenance frequency. At present, the maximum operating temperature of liquid metal circuits such as sodium-potassium alloy and lead-bismuth alloy can reach 600℃. In order to ensure the safe operation of the circuit and realize the functions of calibration and warning, a level probe that can work in a high-temperature liquid metal vapor environment and has good sealing and rapid maintenance functions is required.

[0005] Currently, the liquid level probes used in liquid metal generally use polytetrafluoroethylene and other materials as insulating materials, and the seals are directly made of polytetrafluoroethylene or vacuum flanges. This type of probe has a large number of installation and disassembly parts, and the maintenance convenience is poor. In actual use, the ultimate vacuum sealing degree is not ideal.

[0006] In liquid metal equipment, it is often necessary to measure both temperature and liquid level in one device. For example, liquid metal containers such as expansion tanks and measuring cylinders need to be equipped with at least three liquid level probes for liquid level indication at different heights, and 1 to 3 thermocouple traps are set up for measuring the temperature of the working fluid in the tank. Other pipes such as exhaust pipes, working fluid inlet and outlet pipes are generally required on the head, which often results in cramped space, interference between pipes, and difficulty in operation.

[0007] In view of the above-mentioned deficiencies of ordinary liquid metal probes, conventional liquid metal detection systems are unable to detect liquid metal under high temperature conditions. Summary of the invention

[0008] (I) Purpose of the invention

[0009] In order to overcome the deficiencies of the prior art, the present disclosure provides a multi-purpose high-temperature liquid metal detection system which has a simple structure, is easy to operate and can detect the level and temperature of the high-temperature liquid metal.

[0010] (II) Technical solution

[0011] A high-temperature liquid metal detection system, the system comprising: a power supply, a warning device, a thermocouple temperature display, and a high-temperature liquid metal probe;

[0012] Wherein the high temperature liquid metal probe, the power supply and the warning device are connected in series through wires;

[0013] The high temperature liquid metal probe includes: a transition connector, an insulating component, a sealing component and a structural component for supporting and fixing;

[0014] The sealing member and the insulating member are connected by a transition connector;

[0015] The insulating parts are made of high temperature resistant ceramic material.

[0016] The warning device is a loudspeaker warning device and / or an indicator light.

[0017] The structural parts are made of stainless steel.

[0018] The structural parts include: threaded male joint, upper clamping part, threaded female joint, lower connecting pipe, and center probe; the insulating parts include: ceramic tube;

[0019] The threaded male joint is a pipe fitting with external threads; the threaded female joint is a pipe fitting with internal threads, and a convex ring is provided at one end of the inner surface of the threaded female joint pipe; a convex ring is provided at one end of the outer surface of the lower connecting pipe;

[0020] The threaded female joint is sleeved outside the lower connecting pipe, the threaded male joint is threadedly connected with the threaded female joint, and the lower connecting pipe is pressed by an upper pressing piece, and the upper pressing piece is located inside the threaded female joint;

[0021] The ceramic tube is a long round tube, and the ceramic tube passes through the threaded male joint, the upper clamping piece, the threaded female joint, and the lower connecting pipe in sequence;

[0022] The center probe passes through the ceramic tube.

[0023] The central probe includes a probe fixing end and a probe adjusting end; the probe fixing end is a long round tube and passes through the ceramic tube; the probe adjusting end is a long round cylinder and the beginning end of the probe adjusting end is fixedly connected to the probe fixing end.

[0024] The detection system also includes an armored thermocouple wire; and the armored thermocouple wire is located inside the high-temperature liquid metal probe.

[0025] The central probe is a long straight round tube, and a plug is welded and sealed at the bottom, and an armored thermocouple wire is placed inside.

[0026] The fixed connection between the probe fixing end and the probe adjusting end is welding.

[0027] The transition connector includes: an upper connector, a middle connector, and a lower connector; the upper connector, the middle connector, and the lower connector are all circular ring structures; the sealing member includes: a gasket;

[0028] The probe fixing end is connected to the upper and lower ends of the ceramic tube by using upper and lower connecting pieces respectively;

[0029] The ceramic tube is connected to the upper pressing piece through a middle connecting piece;

[0030] A gasket is arranged between the upper pressing piece and the lower connecting pipe.

[0031] (III) Beneficial effects

[0032] The high-temperature liquid metal detection system disclosed in the present invention adopts a new type of high-temperature liquid metal probe, wherein the high-temperature liquid metal probe disclosed in the present invention adopts a ceramic tube, which is both a structural part and an insulating part, and a metal gasket is used as a sealing part; when other structural parts and connecting parts are made of stainless steel, the maximum operating temperature can reach 650°C. If nickel-based alloys or refractory metal materials are used to make probes and threaded connectors, the temperature resistance can be further improved to 1000°C.

[0033] The probe used in the high temperature liquid metal detection system disclosed in the present invention adopts a quick thread connection, which is convenient and quick to maintain. If a false alarm signal of liquid metal adhesion occurs, it can be quickly disassembled through the thread. During the maintenance process, a blind plug can be used for temporary sealing, and it can be quickly installed after cleaning, so as to reduce the pollution caused by the introduction of air into the equipment.

[0034] The central probe used in the high-temperature liquid metal detection system disclosed in the present invention can be made of either a solid stainless steel bar or a stainless steel tube with a bottom seal welded as a thermocouple well. An armored thermocouple wire is placed inside for temperature measurement. It has the functions of both a probe and a temperature measurement, reduces the top pipe connection of the equipment, and is easy to operate. For example, when a Ф5×0.5mm straight tube is used, it can be used as a thermocouple well with an inner diameter of Ф4mm after the bottom is welded and sealed. The height of the thermocouple wire inside the thermocouple well can be adjusted at will to measure the temperature of the liquid metal at different positions, which is very convenient and flexible to use. In this way, the multifunctional use of the probe can be realized, that is, liquid level detection and liquid metal temperature measurement can be performed simultaneously, greatly improving the space utilization rate of the equipment.

[0035] The probe used in the high-temperature liquid metal detection system disclosed in the present invention has high reliability and is not easy to leak. There are multiple welding points between the probe and the connector. After the sealing of the welding point between the lower connector and the ceramic tube fails, the sealing can still be maintained through the welding point between the upper connector and the ceramic tube, avoiding single point failure. The sealing gasket can be made of different materials such as iron, copper, and nickel according to the requirements of the working fluid compatibility, and the leakage rate can be controlled within 1×10 -11 Pa·m 3 / s or less. There is no axial pressure transmission between the sealing part and the insulating part, which can avoid the situation where the ceramic part is directly over-pressed and cracked during the pressing process of the ordinary probe.

[0036] The probe used in the high-temperature liquid metal detection system disclosed in the present invention has a simple structure, low cost, and is suitable for mass production; the probe has a small cross-sectional area and can be flexibly arranged on the equipment; the probe length can be freely cut and welded as needed, and the probe length can exceed 2m while ensuring verticality. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the probe structure;

[0038] Figure 2 It is a schematic diagram of the application of the probe in the liquid metal container;

[0039] Figure 3 It is a schematic diagram of a high temperature liquid metal detection system;

[0040] Among them, 1 is an upper connector; 2 is a threaded male connector; 3 is a middle connector; 4 is an upper clamping member; 5 is a threaded female connector; 6 is a lower connecting member; 7 is a ceramic tube; 8 is a lower connector; 9 is a probe fixing end; 10 is a probe adjusting end; 11 is a gasket; 12 is a working fluid inlet and outlet pipe; 13 is an overflow port; 14 is a liquid metal level; 15 is a low-level probe; 16 is a middle-level probe; 17 is a high-level probe; 18 is a power supply; 19 is a loudspeaker alarm; 20 is a pilot light; 21 is a thermocouple temperature display; 22 is an armored thermocouple wire; 23 is a high-temperature liquid metal probe; 24 is a liquid metal container; DETAILED DESCRIPTION

[0041] In order to more clearly illustrate the technical solution of the high temperature liquid metal detection system disclosed in the present invention, the following is combined with Figure 1 , Figure 2 and Figure 3 The technical solutions provided by the present disclosure are described in detail in the following specific implementation modes:

[0042] A high-temperature liquid metal detection system, the system includes: a power supply 18, a warning device, a thermocouple temperature display 21, an armored thermocouple wire 22, and a high-temperature liquid metal probe 23; wherein the high-temperature liquid metal probe 23, the power supply 18, and the warning device are connected in series through conduction; wherein the high-temperature liquid metal probe 23 includes: a transition connector, an insulating member, a sealing member, and a structural member for supporting and fixing; wherein the sealing member and the insulating member are connected by a transition connector; wherein the insulating member is made of high-temperature resistant ceramic material. The warning device is a loudspeaker alarm 19 and / or an indicator light 20.

[0043] The structural parts are made of stainless steel. The structural parts include: a threaded male joint 2, an upper clamping piece 4, a threaded female joint 5, a lower connecting pipe 6, and a center probe; the insulating parts include: a ceramic tube 7; wherein the threaded male joint 2 is a pipe fitting with external threads; the threaded female joint 5 is a pipe fitting with internal threads, and a convex ring is provided at one end of the inner surface of the threaded female joint 5; a convex ring is provided at one end of the outer surface of the lower connecting pipe 6; the threaded female joint 5 is sleeved on the outside of the lower connecting pipe 6, the threaded male joint 2 is threadedly connected to the threaded female joint 5, and the lower connecting pipe 6 is compressed by the upper clamping piece 4, and the upper clamping piece 4 is located in the threaded female joint 5; the threaded male joint 2 is threadedly connected to the threaded female joint 5 and the metal gasket 11 is compressed by the upper clamping piece 4 and the lower connecting pipe 6, and the fixing of the lower connecting pipe 6 is achieved by welding on the container head;

[0044] The ceramic tube 7 is a long round tube, and the ceramic tube 7 passes through the threaded male joint 2, the upper clamping piece 4, the threaded female joint 5, and the lower connecting pipe 6 in sequence; the central probe passes through the ceramic tube 7. The central probe includes a probe fixing end 9 and a probe adjusting end 10; wherein the probe fixing end 9 is a long round tube, and the probe fixing end 9 passes through the ceramic tube 7; the probe adjusting end 10 is a long cylinder, and the beginning end of the probe adjusting end 10 is fixedly connected to the probe fixing end 9. The central probe is a long straight round tube, and a plug is welded and sealed at the bottom end, and an armored thermocouple wire 22 is placed inside.

[0045] The fixed connection between the probe fixing end 9 and the probe adjusting end 10 is welded. The transition connector includes: an upper connector 1, a middle connector 3, and a lower connector 8; the upper connector 1, the middle connector 3, and the lower connector 8 are all annular structures. Since the stainless steel structural part and the ceramic tube 7 cannot be directly welded, a transition connector is added, and the inside and outside of the transition connector are welded to stainless steel and ceramic respectively to play a transition role; the sealing part includes: a gasket 11; the probe fixing end 9 and the upper and lower ends of the ceramic tube 7 are connected by the upper and lower connectors 8 respectively; the ceramic tube 7 is connected to the upper clamp 4 through the middle connector 3; a gasket 11 is provided between the upper clamp 4 and the lower connecting pipe 6.

[0046] The high temperature liquid metal detector provided by the present disclosure is according to Figure 3 When the high temperature liquid metal probe 23 is used, only the half part needs to be reserved in the equipment manufacturing stage, that is, Figure 1 The threaded female joint 5 and the lower pipe 6 in the lower pipe 6 can be directly welded to the equipment head, or the lead pipe can be left out and then welded. Before installing the upper part with the probe, use gauze dipped in alcohol or acetone to scrub all parts that may contact the liquid metal, and then install it with a metal gasket 11. After tightening the nut, a leak check should be carried out in time. If a leak is found, the tightening force should be increased. Since this probe uses a full metal seal, there is no risk of crushing the seal, so the tightening force can be slightly larger.

[0047] like Figure 2 The high-temperature liquid metal probe 23 is arranged. If a Ф5×0.5mm stainless steel straight tube is used as the probe, all three probes can be used as a thermocouple well with an inner diameter of 4mm, and armored thermocouples with a diameter of less than Ф3 can penetrate into the bottom of the thermocouple well very smoothly. Generally, it is most appropriate to set a thermocouple well in the low-position probe 15. The temperature of the liquid metal can be accurately measured when the liquid level is high or low, and the measured temperature can be used as a control signal for the heater and the heat preservation heating.

[0048] Replacement and repair situation: The insulating section of the probe provided by the present disclosure is a longer ceramic tube 7 section. Even if metal vapor deposition and adhesion occur locally between the probe and the equipment cylinder, it will not cause a short circuit or a false signal. In extreme cases, if the probe does have a false signal, the upper part of the probe should be unscrewed with a wrench under the protection of internal argon or other inert gas micro-positive pressure, and the probe should be slowly pulled out, and then a male blind plug should be used for temporary sealing. Then use gauze dipped in acetone or alcohol to slowly wipe the metal deposited on the probe and ceramic tube 7, and reinstall it after confirming that there is no adhesion.

[0049] Since the connector and the ceramic tube 7 have a high temperature resistance of more than 1000°C, the liquid level measurement can be achieved when the liquid metal level 14 reaches 1000°C by cooling the tube or using high temperature resistant materials to replace stainless steel as a structural member, and selecting welding materials with a temperature resistance of more than 1000°C. At this temperature, the sealing structure of the present disclosure is still reliable.

[0050] The probe provided by the present invention has been successfully applied in sodium-potassium alloy loops, potassium storage tanks, expansion tanks and measuring cylinders. It is also used as a liquid level probe and a thermocouple trap, which greatly saves space on the upper part of the head and is very convenient to disassemble and assemble.

[0051] Taking the application of a sodium-potassium alloy loop expansion tank as an example, the expansion tank is set at the highest point of the loop. Three probes with thermocouple wells are set in the expansion tank. The distances between the three probes and the bottom of the head are 80mm (low-level probe 15), 280mm (middle-level probe 16), and 480mm (high-level probe 17), respectively. Three K-type armored thermocouple wires 22 are inserted in the thermocouple well. When the loop is initially filled, the pressure difference method is used for normal temperature perfusion to press the working fluid in the storage tank into the loop. When the indicator light 20 of the low-level probe 15 in the expansion tank lights up and a buzzer sounds, it is considered that the working fluid in the loop is full, and the probe signal is the signal to stop the perfusion operation. The temperature display in the thermocouple well is still room temperature. Then the loop temperature is slowly raised to 550°C, and the volume of the working fluid in the loop expands accordingly. The liquid level slowly rises to the middle probe 16 and its indicator light 20 is lit. At this time, the thermocouple temperature display of the middle probe 16 also reaches about 547°C, indicating that the temperature difference between the working fluid in the expansion tank and the main loop is small, and the system is well insulated. During stable operation, the thermocouple in the low-level probe 15 is used as the temperature control point, and the heating wire is wrapped around the outer wall of the expansion tank for thermal compensation to maintain the temperature at 550°C to prevent the expansion tank from dissipating too much heat and causing uneven loop temperature. The high-level probe 17 is set at a height near the overflow port 13. Once the working fluid level in the expansion tank rises abnormally due to misoperation or other reasons, the high-level probe 17 will send an alarm signal and serve as an opening signal for the overflow valve to discharge the working fluid back to prevent high-temperature working fluid from entering the gas covering system. After completing the set test, the system is cooled down, the middle position probe 16 turns off from the lit state, the working fluid is discharged after the temperature drops to 100°C, and the signal of the low position probe 15 also turns off. The liquid metal detection system on the expansion tank completes a complete liquid level and temperature detection process.

[0052] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations to the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these changes and variations. The above-mentioned embodiments or implementation methods are merely illustrative of the present disclosure, and the present disclosure may also be implemented in other specific ways or other specific forms without departing from the gist or essential features of the present disclosure. Therefore, the described implementation methods should be considered illustrative rather than restrictive in any respect. The scope of the present disclosure shall be described by the appended claims, and any changes equivalent to the intent and scope of the claims shall also be included within the scope of the present disclosure.

Claims

1. A high temperature liquid metal detection system, characterized in that: The system comprises: a power supply (18), a warning device, a thermocouple temperature display (21), and a high-temperature liquid metal probe (23); The high-temperature liquid metal probe (23), the power source (18), and the warning device are connected in series via a wire; the high-temperature liquid metal probe (23) comprises: a transition connector, an insulating member, a sealing member, and a structural member for supporting and fixing; The sealing member and the insulating member are connected by a transition connector; The insulating member is made of high temperature resistant ceramic material; The structural parts include: a threaded male joint (2), an upper pressing part (4), a threaded female joint (5), a lower connecting pipe (6), and a center probe; the insulating parts include: a ceramic tube (7); The threaded male joint (2) is a pipe fitting with external threads; the threaded female joint (5) is a pipe fitting with internal threads, and one end of the inner surface of the threaded female joint (5) is provided with a convex ring; one end of the outer surface of the lower connecting pipe (6) is provided with a convex ring; The threaded female joint (5) is sleeved outside the lower connecting pipe (6), the threaded male joint (2) is threadedly connected to the threaded female joint (5), and the lower connecting pipe (6) is pressed by the upper pressing piece (4), and the upper pressing piece (4) is located inside the threaded female joint (5); The ceramic tube (7) is a long round tube, and the ceramic tube (7) passes through the threaded male joint (2), the upper clamping piece (4), the threaded female joint (5), and the lower connecting pipe (6) in sequence; The central probe passes through the ceramic tube (7); The transition connector comprises: an upper connector (1), a middle connector (3), and a lower connector (8); the upper connector (1), the middle connector (3), and the lower connector (8) are all annular structures; the sealing member comprises: a gasket (11); The central probe comprises a probe fixing end (9) and a probe adjusting end (10), and the probe fixing end (9) passes through the ceramic tube (7); The probe fixing end (9) is connected to the upper and lower ends of the ceramic tube (7) respectively via an upper connecting piece and a lower connecting piece (8); The ceramic tube (7) is connected to the upper pressing piece (4) via a middle connecting piece (3); A gasket (11) is provided between the upper pressing piece (4) and the lower connecting pipe (6).

2. A high temperature liquid metal detection system according to claim 1, characterized in that: The warning device is a loudspeaker warning device (19) and / or an indicator light (20).

3. A high temperature liquid metal detection system according to claim 1, characterized in that: The structural parts are made of stainless steel.

4. A high temperature liquid metal detection system according to claim 1, characterized in that: The probe fixing end (9) is a long round tube, the probe adjusting end (10) is a long round cylinder, and the beginning end of the probe adjusting end (10) is fixedly connected to the probe fixing end (9).

5. A high temperature liquid metal detection system according to claim 1 or 4, characterized in that: The detection system further comprises an armored thermocouple wire (22); and the armored thermocouple wire (22) is located inside the high-temperature liquid metal probe (23).

6. A high temperature liquid metal detection system according to claim 5, characterized in that: The central probe is a long straight round tube, and is sealed at the bottom by welding with a plug, and an armored thermocouple wire (22) is placed inside.

7. A high temperature liquid metal detection system according to claim 4, characterized in that: The fixed connection between the probe fixing end (9) and the probe adjusting end (10) is welding.

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