Online continuous temperature measuring device for molten metal

Abstract

The utility model relates to an online continuous temperature measuring device for molten metal, and belongs to the technical field of metallurgical temperature measurement. The device structurally comprises an inner pipe, a temperature sensing sleeve, a supporting pipe and a connector, the inner pipe and the temperature sensing sleeve are each of a structure with one open end and one closed end. The bottom of the closed end of the inner pipe is a temperature measuring point and is inserted into the bottom of an inner cavity of the temperature sensing sleeve, and the closed end of the temperature sensing sleeve is inserted into molten metal for temperature sensing. The temperature sensing sleeve is a high-temperature-resistant metal ceramic tube, and the supporting tube is made of a high-temperature-resistant metal The upper end of the temperature-sensing sleeve is connected with the lower end of the supporting pipe to form an outer protective sleeve, and the ratio L1 / D1 of the depth of a closed pipe of the temperature-sensing sleeve inserted into molten steel to the outer diameter of the bottom end of the closed pipe is larger than or equal to 3. According to the temperature measuring device, the temperature measuring element is protected by controlling the depth of the temperature sensing sleeve inserted into the molten steel to be compared with the outer diameter of the bottom end, and the molten steel temperature can be accurately measured.

Description

Technical Field

[0001] The utility model relates to an online continuous temperature measuring device for molten metal, belonging to the technical field of metallurgical temperature measurement. Background Art

[0002] In the metallurgical production process, temperature parameters are extremely important for metallurgical process control. Poor temperature control will directly lead to a decline in molten steel quality and increased energy consumption. In some working conditions such as high-temperature containers and continuous casting crystallizers in the foundry industry, molten steel temperature control is crucial to production processes and quality safety. At present, traditional continuous temperature measurement of molten steel uses an upper-inserted black body cavity tube or a pre-buried continuous temperature measurement tube for molten steel. First of all, the volume is large and cannot be installed and used in space, which also has a great impact on the flow field of the crystallizer; secondly, the product is made of brittle aluminum carbon material, which has poor thermal shock resistance and is easy to break; finally, due to its thick wall thickness and slow heat conduction speed, continuous temperature measurement of the crystallizer has always been an unresolved problem in the industry.

[0003] Chinese patent CN1333455A discloses a temperature measuring tube for continuous temperature measurement of molten steel, which is used for continuous measurement of the temperature of molten steel in the continuous casting tundish. The main structure of the temperature measuring tube is composed of refractory materials, and its temperature measurement signal comes from the radiation energy emitted from the bottom of the inner tube. Its conduction path first passes through an outer tube with a thickness of 25-40mm, the gap between the outer tube and the inner tube, and the inner tube with a wall thickness of 3mm. Its reaction speed is slow, and there is a large thermal hysteresis. In addition, the inner tube needs to have high thermal shock resistance and high temperature resistance during use, and it is easy to burst, affecting the use of the product. Chinese patents 200720013908.1, 200920143429.0, 201120053767.2, 20072011415.4 and other patents use an inner tube with two ends open and an outer tube with one end open and the other end closed. The protective tube uses the bottom end of the outer tube as a temperature sensing element. The entire outer protective tube is made of the same material and has a thicker bottom end. The thermal response time is improved compared with that of Chinese patent CN1333455A, but it still requires a certain response time, and there is no special change in the contact area between the entire outer tube and the slag layer, resulting in a lower service life under severe erosion conditions. The temperature measuring tube of the above structure needs to be designed with a smoke exhaust structure, thereby destroying the actual temperature field at the bottom of the inner hole, and cannot truly reflect the temperature of the bottom and the solution being measured, nor can it be used to measure the molten steel temperature inside the crystallizer.

[0004] Chinese patent 201720781688.0 discloses a temperature measuring device for molten metal temperature, which adopts a radiation temperature measuring probe and a stopper rod composite temperature measuring sensor to measure the molten steel temperature, and gives the wall thickness of the composite sensor and the aspect ratio of the exposed length, including the wall thickness range of the composite sensor is 1 to 10 mm, the aspect ratio is 1 to 10, etc. The shortcomings of this patented technology are: due to the actual metallurgical field conditions, the crystallizer volume is small, and the stopper rod body has a high carbon content, which will cause the molten steel to be contaminated. The length of the stopper rod and the spatial structure are not suitable for continuous measurement of the molten steel temperature under special conditions. Summary of the invention

[0005] The technical problem to be solved by the utility model is to provide an online continuous temperature measuring device for molten metal, which protects the temperature measuring element by controlling the depth of the temperature sensing sleeve inserted into the molten steel compared with the outer diameter of its bottom end, and can accurately measure the temperature of the molten steel.

[0006] In order to solve the above problems, the specific technical scheme of the utility model is as follows: an online continuous temperature measuring device for molten metal, comprising an inner tube, a temperature sensing sleeve, a support tube, and a connector; the inner tube and the temperature sensing sleeve are respectively open at one end and closed at the other end; the bottom of the closed end of the inner tube is a temperature measuring point, and is inserted into the bottom of the inner cavity of the temperature sensing sleeve, and the closed end of the temperature sensing sleeve is inserted into the molten metal for temperature sensing; the temperature sensing sleeve is a high-temperature resistant metal ceramic tube, and the support tube is a high-temperature resistant metal material; the upper end of the temperature sensing sleeve is connected to the lower end of the support tube to form an outer protective sleeve, and the ratio of the depth of the closed tube of the temperature sensing sleeve inserted into the molten steel to the outer diameter of its bottom end L1 / D1≥3.

[0007] The length of the temperature sensing sleeve is ≥100mm, the wall thickness of the closed end of the temperature sensing sleeve is 2-10mm, and the inner diameter is 8-20mm; the wall thickness of the lower half of the temperature sensing sleeve is less than that of the upper half, and the junction of different wall thicknesses adopts an outer cone shape transition.

[0008] A gap is provided between the temperature sensing sleeve and the inner tube, and a heat conduction buffer tube with an open upper end and a closed lower end is arranged in the gap.

[0009] The outer surface of the temperature sensing sleeve is coated with high temperature anti-oxidation paint with a temperature resistance of ≥1700°C.

[0010] A limit block is arranged in the inner cavity of the support tube, which is fixed to the middle of the support tube by screws, a through hole is arranged on the midline of the limit block, and the inner tube passes through the through hole of the limit block and is supported in the support tube.

[0011] The support tube is larger than the diameter of the temperature sensing sleeve, and the upper end of the temperature sensing sleeve is provided at the lower end of the support tube for coaxial sealing connection.

[0012] The sealed connection between the support pipe and the temperature sensing sleeve includes dense filling and bonding with high-temperature refractory mud, threaded connection, clamping or heating expansion positioning.

[0013] The inner tube is an alumina ceramic tube, and the temperature measuring element inside the inner tube is a thermocouple or a photoelectric detector.

[0014] The molten metal online continuous temperature measurement device of the present application adopts the above structure and has the following advantages:

[0015] 1. Setting the depth of the temperature sensing sleeve inserted into the molten steel relative to the outer diameter of its bottom not only ensures the temperature transmission speed, but also protects the measuring elements in the inner sleeve;

[0016] 2. The temperature sensing sleeve adopts an outer cone shape transition to enhance the corrosion and oxidation resistance at the slag line, ensure the strength of the temperature sensing sleeve, and reduce stress concentration through the outer cone shape transition to increase service life;

[0017] 3. Setting up a thermal protection tube can not only improve the sensor response speed, but also protect the inner wall from oxidation and extend its service life;

[0018] 4. A limit block is set in the inner cavity of the support tube to support and limit the inner tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a temperature measuring device for continuously measuring molten metal.

[0020] Figure 2 for Figure 1 A partial enlarged view of .

[0021] Figure 3 This is the application status diagram of the temperature measuring device for continuously measuring molten metal. DETAILED DESCRIPTION

[0022] like Figure 1 and Figure 2 As shown, a temperature measuring device for continuously measuring molten metal includes an inner tube 12, a temperature sensing sleeve 8, a support tube 10, and a connector 14; the inner tube 12 and the temperature sensing sleeve 8 are respectively open at one end and closed at the other end; the bottom of the closed end of the inner tube 12 is a temperature measuring point, and is inserted into the bottom of the inner cavity of the temperature sensing sleeve 8, and the closed end of the temperature sensing sleeve 8 is inserted into the molten metal for temperature sensing; the temperature sensing sleeve 8 is a high-temperature resistant metal ceramic tube, and the support tube 10 is a high-temperature resistant metal material; the upper end of the temperature sensing sleeve 8 is connected to the lower end of the support tube 10 to form an outer protective sleeve, and the ratio of the depth of the closed tube of the temperature sensing sleeve 8 inserted into the molten steel to the outer diameter of its bottom end L1 / D1≥3. The temperature sensing sleeve 8 can not only achieve the purpose of quickly transmitting the temperature to the temperature measuring point, but also has the purpose of protecting the temperature measuring element.

[0023] The length of the temperature sensing sleeve 8 of the outer protective sleeve is ≥100mm, the wall thickness of the closed end of the temperature sensing sleeve is 2~10mm, and the inner diameter is 8~20mm; the wall thickness of the lower half of the temperature sensing sleeve 8 is less than that of the upper half, and the junction of different wall thicknesses adopts an outer cone shape transition. The lower half has a thin wall, fast heat transfer speed, and improves the temperature measurement speed. The upper half has a thick wall, which enhances the corrosion and oxidation resistance at the slag line, ensures the strength of the temperature sensing sleeve, and reduces stress concentration through the outer cone shape transition, thereby improving the service life.

[0024] There is a gap between the temperature sensing sleeve 8 and the inner tube 12, and a heat conductive protection tube 9 with an upper end opening and a lower end closed is arranged in the gap. The heat conductive protection tube 9 is composed of a tubular structure of metal oxide and aluminum powder, and the metal oxide is one or a mixture of aluminum oxide, magnesium oxide, and zirconium oxide. The heat conductive protection tube 9 fills the gap between the temperature sensing sleeve 8 and the inner tube 12 to protect the inner tube from vibration shock and thermal stress, and secondly increases the heat conduction between the temperature sensing sleeve 8 and the inner tube 12, and improves the sensor response speed; the aluminum powder consumes oxygen, protects the inner wall of the temperature sensing sleeve 8 from oxidation, and prolongs the service life.

[0025] The outer surface of the temperature sensing sleeve 8 is coated with high temperature anti-oxidation paint, and the firing temperature is ≥1700° C., so as to ensure that the outer surface of the temperature sensing sleeve will not change whether it is in molten metal or in air.

[0026] A stopper 11 is provided in the inner cavity of the support tube 10, the stopper 11 is fixed to the middle of the support tube 10 by screws, a through hole is provided in the midline of the stopper 11, and the inner tube 12 passes through the through hole of the stopper 11 and is supported in the support tube 10. The stopper 11 supports and limits the inner tube 12, ensuring the coaxiality of the inner tube 12 and the temperature sensing sleeve 8.

[0027] The support tube 10 is larger than the diameter of the temperature sensing sleeve 8, and the upper end of the temperature sensing sleeve 8 is coaxially sealed at the lower end of the support tube 10. The sealing connection includes but is not limited to dense filling and bonding with high-temperature refractory mud, threaded connection, clamping or heating expansion positioning.

[0028] like Figure 3As shown, the working process of the temperature measuring device for continuously measuring molten metal of the present application is as follows: the molten metal 2 is placed in a container 1 with a protective layer, and is covered with protective slag 3. The temperature measuring device of the present application is positioned by a bracket 4, and the cable of the temperature measuring element passes through the fixed block 13 and the connector 14 and is connected to the signal processor 5. When the temperature sensing sleeve 8 of the temperature measuring device of the present application is inserted into the molten metal 2, the heat of the molten metal 2 is quickly transferred to the temperature measuring element through the temperature sensing sleeve 8, the thermal protection tube 9 and the inner tube 12, so that the temperature measuring element converts the temperature information into an electrical signal, transmits it to the signal processor 5, and displays the temperature of the molten metal in real time. The temperature measuring device of the present application is simple to operate and small in size. It is suitable for small spaces and low liquid levels. Due to the structure of the thermal protection tube 9, it is more suitable for multiple rapid cooling and hot plugging conditions.

Claims

1. A molten metal online continuous temperature measurement device, characterized in that: The invention comprises an inner tube (12), a temperature sensing sleeve (8), a support tube (10), and a connector (14); the inner tube (12) and the temperature sensing sleeve (8) are respectively structures with one end open and the other end closed; the bottom of the closed end of the inner tube (12) is a temperature measuring point and is inserted into the bottom of the inner cavity of the temperature sensing sleeve (8); the closed end of the temperature sensing sleeve (8) is inserted into molten metal for temperature sensing; the temperature sensing sleeve (8) is a high temperature resistant metal ceramic tube, and the support tube (10) is a high temperature resistant metal material; the upper end of the temperature sensing sleeve (8) is connected to the lower end of the support tube (10) to form an outer protective sleeve, and the ratio of the depth of the closed tube of the temperature sensing sleeve (8) inserted into the molten steel to the outer diameter of its bottom end L1 / D1≥3.

2. The molten metal online continuous temperature measurement device according to claim 1 is characterized in that: The length of the temperature sensing sleeve (8) is ≥100 mm, the wall thickness of the closed end of the temperature sensing sleeve is 2-10 mm, and the inner diameter is 8-20 mm; the wall thickness of the lower half of the temperature sensing sleeve (8) is less than that of the upper half, and the junction of different wall thicknesses adopts an external cone shape transition.

3. The molten metal online continuous temperature measurement device according to claim 1 is characterized in that: A gap is provided between the temperature sensing sleeve (8) and the inner tube (12), and a heat-conducting buffer tube (9) having an open upper end and a closed lower end is arranged in the gap.

4. The molten metal online continuous temperature measurement device according to claim 1 is characterized in that: The outer surface of the temperature sensing sleeve (8) is coated with a high-temperature anti-oxidation paint with a temperature resistance of ≥1700°C.

5. The molten metal online continuous temperature measurement device according to claim 1, characterized in that: A limit block (11) is provided in the inner cavity of the support tube (10), the limit block (11) is fixed to the middle part of the support tube (10) by means of screws, a through hole is provided on the midline of the limit block (11), and the inner tube (12) passes through the through hole of the limit block (11) and is supported in the support tube (10).

6. The molten metal online continuous temperature measurement device according to claim 1, characterized in that: The support tube (10) is larger than the diameter of the temperature sensing sleeve (8), and the upper end of the temperature sensing sleeve (8) is provided at the lower end of the support tube (10) for coaxial sealing connection.

7. The molten metal online continuous temperature measurement device according to claim 6, characterized in that: The sealed connection between the support tube (10) and the temperature sensing sleeve (8) includes connection by dense filling and bonding with high-temperature refractory mud, threaded connection, clamping or heating expansion positioning.

8. The molten metal online continuous temperature measurement device according to claim 1, characterized in that: The inner tube (12) is an alumina ceramic tube, and the temperature measuring element inside the inner tube (12) is a thermocouple or a photoelectric detector.

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