Thermocouple

Abstract

The utility model relates to a thermocouple. The thermocouple comprises a protection tube (1) with an open end (11), a sealing block (2) arranged in the open end (11), and a thermocouple wire (3) arranged in the protection tube (1). And one end of the thermocouple wire (3) passes through the sealing block (2) and extends out of the protection tube (1). The sealing block (2) is made of fluororubber. The sealing block of the thermocouple has good high temperature resistance and is not easy to break, so that the cold end sealing performance of the thermocouple in a long-term high-temperature use environment is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to thermocouple technical field especially is related to cold end packaging of thermocouple. BACKGROUND

[0002] In the industrial production process, temperature is one of important parameters that need to be measured and controlled. In temperature measurement, the application of thermocouple is extremely wide, it has simple structure, convenient manufacturing, high precision and output signal is convenient for remote transmission and many advantages. In addition, since the thermocouple is a passive sensor, no external power supply is needed during measurement, and it is very convenient to use, so it is often used to measure the temperature of gas or liquid in the furnace, pipeline and the surface temperature of solid.

[0003] The temperature measurement principle of thermocouple is based on the so-called Seebeck effect: when two conductors of different materials form a closed loop, and there is a temperature gradient between the two ends, there will be current in the loop, and at this time, there is electromotive force between the two ends-thermal electromotive force. One end of the thermocouple directly used for measuring medium temperature is the measurement end (also known as the hot end), and the other end is the reference end / base end (also known as the cold end). The thermocouple of the prior art usually uses magnesium oxide as an insulating material. Magnesium oxide has strong hygroscopicity, and the insulation resistance will decrease significantly after magnesium oxide absorbs moisture, which affects the measurement accuracy of the thermocouple. Therefore, the quality of the cold end packaging is one of the key factors affecting the performance of the thermocouple.

[0004] At present, the cold end packaging of the thermocouple mainly adopts epoxy resin pouring or glass sintering sealing. The epoxy resin has poor high-temperature resistance, resulting in a narrow working temperature range of the thermocouple. The glass has high melting point and good high-temperature resistance, but the glass block formed by sintering is easy to break, thereby causing sealing failure. INVENTION CONTENTS

[0005] The utility model aims at solving at least one of the above problems and / or other problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, according to one aspect of the utility model, a thermocouple is provided, which comprises a protective tube with an open end, a sealing block arranged in the open end, and a thermocouple wire arranged in the protective tube. One end of the thermocouple wire extends out of the protective tube through the sealing block. The sealing block is made of fluorine rubber.

[0007] According to an embodiment of the utility model, the protective tube and the sealing block are fixed together by a rolling process.

[0008] According to an embodiment of the utility model, the protective tube is formed with a recess at the outer peripheral surface of the open end, and the protective tube is formed with a protrusion corresponding to the recess at the inner peripheral surface thereof, and the protrusion extrudes the sealing block.

[0009] According to an embodiment of the present application, the concave part and the convex part are continuous in the whole circumference of the protection tube.

[0010] According to an embodiment of the present application, the thermocouple wire comprises two wire materials made of different conductive materials, the first ends of the two wire materials are joined together inside the protection tube, and the second ends of the two wire materials pass through the sealing block in parallel with each other.

[0011] According to an embodiment of the present application, an insulator is arranged between the thermocouple wire and the protection tube.

[0012] According to an embodiment of the present application, the insulator is made of magnesium oxide.

[0013] According to an embodiment of the present application, the protection tube is made of stainless steel.

[0014] The thermocouple of the present application adopts the sealing block made of fluorine rubber, which has good high-temperature resistance, corrosion resistance, oil resistance and insulation, and is not easy to break, thereby ensuring the cold end sealing performance of the thermocouple in a long-term high-temperature use environment. BRIEF DESCRIPTION OF DRAWINGS

[0015] The features and advantages of the present application will be clearly understood through the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are only schematic and are not necessarily drawn to scale, and therefore should not be considered as limiting the present application, in which:

[0016] Figure 1 A perspective view of a thermocouple according to one embodiment of the present application is shown.

[0017] Figure 2 A perspective view of a thermocouple according to one embodiment of the present application is shown. Figure 1 An exploded view of the thermocouple shown.

[0018] Figure 3 A perspective view of a thermocouple according to one embodiment of the present application is shown. Figure 1 A cross-sectional view of the thermocouple shown at the open end of the protection tube.

[0019] BRIEF DESCRIPTION OF DRAWINGS

[0020] 1, protection tube; 11, open end; 12, concave part; 13, convex part; 2, sealing block; 3, thermocouple wire; 31, wire material; 4, insulator. DETAILED DESCRIPTION

[0021] Embodiments of the present application will be described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present application. Also, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Rather, the scope of the present application is defined by the appended claims.

[0022] The terms "comprise" and "comprising" used in the following are used to mean that the elements listed after the word comprise are included in the comprising step or composition, and that additional elements are optionally present.

[0023] Figures 1-3 A thermocouple according to an embodiment of the present application is shown. As shown in Figure 1 and Figure 2 , the thermocouple according to the embodiment can include a protective tube 1, a sealing block 2, a thermocouple wire 3, and an insulator 4.

[0024] The protective tube 1 has a tubular structure with an open end 11 at one end and a closed end at the other end. The protective tube 1 can be made of stainless steel. For example, the protective tube 1 can be made of Inconel 600 or 601, which mainly contains nickel and chromium, and also contains a small amount of aluminum, titanium and other elements, and exhibits excellent corrosion resistance and oxidation resistance, and can maintain good strength and creep performance at high temperatures. Inconel 600 or 601, which mainly contains nickel and chromium, and also contains a small amount of aluminum, titanium and other elements, and exhibits excellent corrosion resistance and oxidation resistance, and can maintain good strength and creep performance at high temperatures.

[0025] The sealing block 2 can be a cylindrical structure made of fluororubber, which has good elasticity, high temperature resistance, corrosion resistance, oil resistance and insulation performance. The sealing block 2 is encapsulated at the open end 11 of the protective tube 1, and its diameter is adapted to the inner diameter of the protective tube 1.

[0026] The thermocouple wire 3 is arranged in the protective tube 1, one end of which passes through the sealing block 2 and extends out of the protective tube 1. The left end of the thermocouple wire 3 in Figure 2 is the measuring end, also known as the hot end. The right part of the thermocouple wire 3 in Figure 2 is the reference end, also known as the cold end.

[0027] The sealing block 2 can be slightly larger than the opening of the opening end 11. The sealing block 2 is provided with through holes for the thermocouple wire 3 to pass through, and the through holes can be slightly smaller than the diameter of the thermocouple wire 3. Thus, the elasticity of the fluororubber can be utilized to enable the sealing block 2 to be fixed to the opening end 11 in an interference fit, on the one hand, and to be fixed to the thermocouple wire 3 passing through the through holes in an interference fit, on the other hand.

[0028] In the present embodiment, the protective tube 1 and the sealing block 2 are fixed together by a rolling process. Specifically, after the sealing block 2 is arranged at the opening end 11 of the protective tube 1, the outer circumferential surface of the protective tube 1 is rolled by means of a rolling tool, thereby forming a recess 12 as shown in Figure 3 on the outer circumferential surface of the protective tube 1. Correspondingly, a protrusion 13 corresponding to the recess 12 is formed on the inner circumferential surface of the protective tube 1, thereby clamping the sealing block 2 inwardly. The recess 12 and the protrusion 13 are preferably continuous in the entire circumferential direction of the protective tube 1. In some embodiments, a plurality of recesses 12 and a plurality of protrusions 13 can be rolled in the axial direction of the protective tube 1 at intervals.

[0029] With continued reference to Figure 3 , the thermocouple wire 3 can include two wire materials 31 made of different conductive materials. As an example, one of the wire materials 31 can be made of nickel-chromium-silicon (NiCrSi), and the other wire material 31 can be made of nickel-silicon (NiSi). The left ends of the two wire materials 31 as shown in Figure 2 are joined together inside the protective tube 1, constituting the hot end of the thermocouple. The right ends of the two wire materials 31 as shown in Figure 2 extend out of the protective tube 1 through the sealing block 2 in parallel with each other, constituting the cold end of the thermocouple. The two wire materials 31 are respectively connected to compensation wires at the cold end, thereby forming a loop. When the temperatures at the two ends of the thermocouple wire 3 are different, an electromotive force is generated in the loop, so that temperature measurement can be performed.

[0030] As shown in Figure 2 and Figure 3 , an insulator 4 made of insulating material is further arranged between the thermocouple wire 3 and the protective tube 1 inside the protective tube 1. The insulating material can be selected from magnesium oxide. For example, powdered magnesium oxide is sintered between the thermocouple wire 3 and the protective tube 1 after being pressurized, thereby forming the insulator 4.

[0031] The cold end of the thermocouple in the prior art is usually sealed by a sealing block made of glass at the open end of the protection tube. Especially in the long-term high-temperature use environment, the glass block is easy to break and cause sealing failure. In contrast, the thermocouple according to the utility model adopts a sealing block 2 made of fluororubber, which not only has good high-temperature resistance, corrosion resistance, oil resistance and good insulation, but also is not easy to break in use, thereby ensuring the sealing performance and temperature measurement function of the thermocouple in the long-term high-temperature environment.

[0032] In addition, the sealing block 2 and the protection tube 1 can be fixed by a rolling process, and the concave part 12 and the convex part 13 formed by the rolling process can be continuous on the entire circumference of the protection tube 1. This is conducive to further increasing the sealing reliability between the protection tube 1 and the sealing block 2, avoiding the leakage of the insulation material between the protection tube 1 and the thermocouple wire 3, thereby ensuring the cold end sealing performance of the thermocouple in the long-term high-temperature use environment.

[0033] Various modifications and variations to the disclosed embodiments of the present application can be made without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are intended as illustrative only and are not intended to limit the true scope of the present application, which is to be set forth in the claims.

Claims

1. A thermocouple comprising: a protective tube (1) having an open end (11); a sealing block (2) provided at the open end (11); and a thermocouple wire (3) provided inside the protective tube (1), one end of the thermocouple wire (3) protruding outside the protective tube (1) through the sealing block (2), characterized in that the sealing block (2) is made of fluorine rubber. The protective tube (1) and the sealing block (2) are fixed together by a rolling process.

2. The thermocouple of claim 1, wherein, The protective tube (1) is formed with a recess (12) on its outer peripheral surface at the open end (11), and the protective tube (1) is formed with a protrusion (13) on its inner peripheral surface corresponding to the recess (12), the protrusion (13) pressing the sealing block (2).

3. The thermocouple of claim 2, wherein, The recess (12) and the protrusion (13) are continuous in the entire circumferential direction of the protective tube (1).

4. The thermocouple of claim 3, wherein, The thermocouple wire (3) includes two wire materials (31) made of different conductive materials, first ends of the two wire materials (31) being joined together inside the protective tube (1), second ends of the two wire materials (31) passing through the sealing block (2) in parallel to each other.

5. The thermocouple according to any one of claims 1 to 4, characterized in that An insulator (4) is provided between the thermocouple wire (3) and the protective tube (1).

6. The thermocouple according to any one of claims 1 to 4, characterized in that The insulator (4) is made of magnesium oxide.

7. The thermocouple of claim 6, wherein, The protective tube (1) is made of stainless steel.

8. The thermocouple of any one of claims 1 to 4, wherein, ​

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