Out-of-furnace positioner for temperature field test of cheap metal thermocouple verification furnace

Abstract

The invention discloses an out-of-furnace positioner for a temperature field test of a cheap metal thermocouple verification furnace, and relates to the technical field of thermocouple calibration. A telescopic supporting mechanism is arranged between the supporting base and the horizontal positioning block, two positioning pipe holes are formed in the left side end of the long positioning block, two first standard couple holes are formed in the right side end of the long positioning block, the two first standard couple holes are communicated with the two positioning pipe holes respectively, and two second standard couple holes are formed in the horizontal positioning block. A long positioning block is arranged in the device, so that the constraint length of the position of the standard couple for testing is increased; the device is further provided with a horizontal positioning block and a telescopic supporting mechanism which are not prone to abrasion, the horizontal positioning block is connected with the long positioning block through a connecting bolt, the position of the standard couple for testing is further restrained, the uncertainty of the testing result of the temperature field of the verification furnace caused by position deviation of the temperature measuring point of the standard couple is reduced, and the testing accuracy is improved. And the temperature field of the cheap metal thermocouple verification furnace can be more accurately tested, represented and evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of thermocouple calibration, in particular to an external positioner for temperature field testing of a low-cost metal thermocouple calibration furnace. Background Art

[0002] A thermocouple is a thermometer made of two conductors of different materials based on the Seebeck effect. A thermocouple calibration furnace (also known as a calibration furnace) is an electric heating device that provides heat for thermocouple calibration. It primarily consists of a furnace tube, heating element, insulation, and outer casing. The heating element is wound around the outside of the furnace tube, and a thermocouple is placed inside. The temperature inside the furnace tube is controlled by a thermostat that adjusts the power of the heating element based on the deviation between the temperature measured by the thermocouple and the set value. A thermocouple calibration furnace is typically placed horizontally and is also called a horizontal thermocouple calibration furnace.

[0003] Calibration furnaces can be divided into precious metal thermocouple calibration furnaces (referred to as precious metal thermocouple furnaces) and inexpensive metal thermocouple calibration furnaces (referred to as inexpensive metal thermocouple furnaces). The furnace tube size of precious metal thermocouple furnaces is typically Φ20×600mm (inner diameter × length, the same below), while the furnace tube size of inexpensive metal thermocouple furnaces is typically Φ40×600mm. The distribution of the calibration furnace's temperature field is one of the important sources of uncertainty in thermocouple calibration. According to the national JJF 1184-2024 Technical Specification for Temperature Field Testing of Thermocouple Calibration Furnaces, the temperature field of the calibration furnace must be retested regularly, and the interval should generally not exceed one year.

[0004] When testing the temperature field of a thermocouple furnace, a cup-shaped or hole-shaped temperature-equalizing block is placed inside the furnace tube, a positioning block is placed at the measuring end of the calibration furnace, and a positioning tube with one end sealed is inserted into the bottom of the temperature-equalizing block. On the one hand, the cup-shaped temperature-equalizing block does not support the positioning tube, so the positioning tube is suspended in the cup-shaped temperature-equalizing block. On the other hand, there is a gap between the positioning block opening and the positioning tube. Furthermore, the positioning block is usually made of mullite, a material that is resistant to high temperatures and prone to wear. After long-term use, the gap between the positioning block opening and the positioning tube increases, making it difficult for the positioning tube to be parallel to the center axis of the furnace tube. This increases the uncertainty of the temperature field measurement results, affecting the testing, characterization, and evaluation of the temperature field performance of the thermocouple calibration furnace.

[0005] Therefore, the present application proposes an off-furnace positioner for temperature field testing of a low-cost metal thermocouple calibration furnace to solve the above-mentioned problems. Summary of the Invention

[0006] The purpose of the present invention is to provide an external positioner for temperature field testing of a low-cost metal thermocouple calibration furnace, which solves the technical problems raised in the background technology.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an off-furnace positioner for temperature field testing of a low-cost metal thermocouple calibration furnace, comprising a supporting base, a connecting bolt, a horizontal positioning block and a long positioning block, the outer diameters of the horizontal positioning block and the long positioning block being the same, the left end of the long positioning block being inserted into the furnace tube of the low-cost metal thermocouple calibration furnace, the horizontal positioning block being located above the supporting base, a telescopic supporting mechanism being provided between the supporting base and the horizontal positioning block, the long positioning block being located on the left side of the horizontal positioning block, two connecting through holes 1 being provided on the long positioning block, two connecting through holes 2 being provided on the horizontal positioning block, the connecting through holes 1 and 2 being coaxially arranged, the right end of the connecting bolt passing through the connecting through holes 1 and 2 in sequence and being connected with a nut, the long positioning block Two positioning tube holes are provided at the left end, one of which is coaxially arranged with the elongated positioning block, and two standard even holes 1 are provided at the right end of the elongated positioning block, and the two standard even holes 1 are respectively connected to the two positioning tube holes, and the inner diameter of the positioning tube hole is larger than the inner diameter of the standard even hole 1, and two standard even holes 2 are provided on the horizontal positioning block, and the two standard even holes 1 are respectively coaxially arranged with the two standard even holes 2, and the standard even hole 1 has the same size as the standard even hole 2, and a blind hole is provided at the right end of the horizontal positioning block, and a horizontal bubble is provided in the blind hole, and the central axis of the blind hole is parallel to the central axis of the horizontal positioning block, and a positioning ring is provided on the outer wall of the elongated positioning block, and the positioning ring is integrally formed with the elongated positioning block, and the outer diameter of the positioning ring is larger than the outer diameter of the elongated positioning block;

[0008] The telescopic support mechanism comprises a telescopic outer cylinder, a clamping plate, a telescopic adjustment rod, an adjustment ring and a V-shaped bracket.

[0009] Preferably, a plurality of blind grooves are provided on the outer side wall of the horizontal positioning block, and there are at least three blind grooves, and the central axis of the blind groove is parallel to the central axis of the horizontal positioning block.

[0010] Preferably, the telescopic outer cylinder is fixed on the support base, and several clamping plates are provided, and several of the clamping plates are fixed on the upper end of the telescopic outer cylinder. The lower end of the telescopic adjustment rod extends into the telescopic outer cylinder, and the upper end of the telescopic adjustment rod is fixedly connected to the lower end of the V-shaped bracket. The adjustment ring is sleeved on the telescopic outer cylinder, and several of the clamping plates are threadedly connected to the adjustment ring.

[0011] Preferably, the long positioning block is made of mullite, high-alumina brick or corundum; the horizontal positioning block is made of transparent materials such as quartz glass, ordinary glass, or metal iron, aluminum, copper, steel or corundum; the connecting bolt is made of stainless steel or corundum, and the V-shaped bracket is made of aluminum alloy or stainless steel.

[0012] Compared with related technologies, the external positioner for temperature field testing of a low-cost metal thermocouple calibration furnace provided by the present invention has the following beneficial effects:

[0013] The present invention provides an off-furnace positioner for testing the temperature field of a low-cost metal thermocouple calibration furnace. The device includes a long positioning block, which increases the length of the constraint on the position of a test standard thermocouple and reduces the deflection of the test standard thermocouple caused by the clearance between the positioning block opening and the test positioning tube and the test standard thermocouple, while also preventing significant additional interference with the temperature field within the furnace. The device also includes a wear-resistant horizontal positioning block and a telescopic support mechanism. The horizontal positioning block is connected to the long positioning block via a connecting bolt, further constraining the position of the test standard thermocouple. A level bubble is also provided on the horizontal positioning block to directly display the horizontality of the horizontal positioning block and facilitate adjustment of the horizontal positioning block using the telescopic support mechanism, providing a "ruler" for ensuring that the test standard thermocouple is parallel to the central axis of the furnace tube. The present invention reduces the uncertainty in the calibration furnace temperature field test results caused by positional deviation of the standard thermocouple temperature measurement point, enabling more accurate testing, characterization, and evaluation of the temperature field of a low-cost metal thermocouple calibration furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the installation of a conventional cup-type temperature equalizing block low-cost metal couple furnace temperature field test of the present invention;

[0015] Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention;

[0016] Figure 3 This is a schematic diagram of the three-dimensional structure of the present invention from another angle;

[0017] Figure 4 This is a cross-sectional diagram of the long positioning block and the horizontal positioning block of the present invention after being matched;

[0018] Figure 5 This is a schematic diagram of the explosion structure of the telescopic outer cylinder of the present invention;

[0019] Figure 6 for Figure 5 A partial enlarged view of the middle A;

[0020] Figure 7 This is a schematic diagram of the three-dimensional structure of the long positioning block of the present invention;

[0021] Figure 8 It is a schematic diagram of the three-dimensional structure of the horizontal positioning block of the present invention.

[0022] In the figure: 1. Furnace tube; 2. Positioning block at the temperature control end; 3. Cup-type temperature equalizing block; 4. Positioning block at the measuring end; 5. Positioning tube for testing; 6. Standard coupler for testing; 7. Support base; 8. Telescopic outer cylinder; 9. Clamping plate; 10. Telescopic adjustment rod; 11. Adjustment ring; 12. V-shaped bracket; 13. Horizontal positioning block; 14. Long positioning block; 15. Positioning ring; 16. Connecting bolt; 17. Positioning tube hole; 18. Connecting through hole 1; 19. Standard coupler hole 1; 20. Standard coupler hole 2; 21. Blind groove; 22. Level bubble; 23. Connecting through hole 2; 24. Blind hole. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] See also Figure 1 , Figure 1 This is a cross-sectional view of the existing cup-type temperature-averaging block low-cost metal couple furnace temperature field test installation structure, which is provided with a furnace tube 1, a test positioning tube 5 and a test standard couple 6. The inner diameter of the furnace tube 1 is 40mm and the length is 600mm. The left and right ends of the furnace tube 1 are respectively provided with a temperature control end positioning block 2 and a measuring end positioning block 4. A cup-type temperature-averaging block 3 is provided on the inside of the furnace tube 1. The inner bottom surface of the cup-type temperature-averaging block 3 is located at the axial center of the furnace tube. The left end of the test positioning tube 5 passes through the measuring end positioning block 4 and extends to the cup-type temperature-averaging block 3. The test standard couple 6 is provided with a The left end extends to the inside of the test positioning tube 5. The left ends of the test positioning tube 5 and the test standard couple 6 are suspended in the cup-type temperature-isolating block 3 without any supporting structure. On the other hand, the measuring end positioning block 4 is relatively short, and there is a fitting gap between its opening and the test positioning tube 5. The measuring end positioning block 4 is usually made of a high-temperature resistant and easily-worn material, such as mullite. With the long-term use of the measuring end positioning block 4, the aperture of its hole gradually increases, causing the fitting gap between the opening of the measuring end positioning block 4 and the test positioning tube 5 to gradually increase. Therefore, the position of the temperature-sensing point of the test standard couple 6 inserted in the test positioning tube 5 is usually difficult to control. When measuring the axial temperature field, the trajectory of the temperature-sensing point of the test standard couple 6 is not parallel to the central axis of the furnace tube 1; when measuring the radial temperature field, the distance between the temperature-sensing points of the two test standard couples 6 does not meet the 14mm requirement of the metrological test specification. In the prior art, since the position of the temperature sensing point of the standard thermocouple 6 used for testing does not meet the requirements, the uncertainty of the temperature field test of the calibration furnace increases, and the temperature field of the low-cost metal thermocouple calibration furnace cannot be accurately tested, characterized, and evaluated.

[0026] See also Figure 2-Figure 7The present invention provides a technical solution: an external positioner for temperature field testing of a low-cost metal thermocouple calibration furnace, comprising a support base 7, a connecting bolt 16, a horizontal positioning block 13 and a long positioning block 14, the outer diameter of the long positioning block 14 is 39 mm, the outer diameter of the positioning ring 15 is 50 mm, the length of the long positioning block 14 is 110 mm, the length of the positioning ring 15 is 10 mm, the length of the horizontal positioning block 13 is 80 mm, the outer diameter of the horizontal positioning block 13 and the long positioning block 14 are the same, the left end of the long positioning block 14 is inserted into the furnace tube 1 of the low-cost metal thermocouple calibration furnace, the horizontal positioning block 13 is located above the support base 7, and the support base 7 and the horizontal positioning block 13 are connected. A telescopic support mechanism is provided between the horizontal positioning block 13 and the long positioning block 14, which is convenient for supporting the horizontal positioning block 13 and the long positioning block 14. The long positioning block 14 is located on the left side of the horizontal positioning block 13. Two connecting through holes 18 are provided on the long positioning block 14, and two connecting through holes 23 are provided on the horizontal positioning block 13. The connecting through hole 18 and the connecting through hole 23 are coaxially arranged. The inner diameter of the connecting through hole 18 and the connecting through hole 23 is 7mm. The right end of the connecting bolt 16 passes through the connecting through hole 18 and the connecting through hole 23 in turn and is connected with a nut. The model of the connecting bolt 16 is M6, and the length of the threaded portion of the connecting bolt 16 is 200mm. The left end of the long positioning block 14 is provided with a Two positioning tube holes 17, positioning tube holes 17 are used to place the test positioning tube 5 for the temperature field test of the low-cost metal thermocouple calibration furnace. The inner diameter of the positioning tube hole 17 is larger than the outer diameter of the test positioning tube 5. One of the positioning tube holes 17 is coaxially arranged with the long positioning block 14. The right end of the long positioning block 14 is provided with two standard even holes 19. The two standard even holes 19 are respectively connected to the two positioning tube holes 17. The inner diameter of the positioning tube hole 17 is larger than the inner diameter of the standard even hole 19. The horizontal positioning block 13 is provided with two standard even holes 20. The standard even hole 20 is in the form of a through hole. The two standard even holes 19 are coaxially arranged with the two standard even holes 20 respectively. The standard even hole 19 is connected to the standard The even hole 20 has the same size, the standard even hole 19 and the standard even hole 20 are used to place the test standard even 6 for the temperature field test of the low-cost metal thermocouple calibration furnace, and the inner diameter of the standard even hole 19 and the standard even hole 20 is larger than the outer diameter of the test standard even 6; during the temperature field test of the calibration furnace, the outer diameter of the test standard even 6 is 4mm, the outer diameter of the test positioning tube 5 is 8mm and the length is 320mm, the diameter of the positioning tube hole 17 on the long positioning block 14 is 9mm, the diameter of the standard even hole 19 is 5mm, the length of the positioning tube hole 17 on the long positioning block 14 is 70mm, the length of the test standard even 6 is 40mm, and the radial distance between the two test positioning tubes 5 is 14mm;A blind hole 24 is provided at the right end of the horizontal positioning block 13. A level bubble 22 is provided in the blind hole 24. The central axis of the blind hole 24 is parallel to the central axis of the horizontal positioning block 13. The diameter of the level bubble 22 is 6 mm, the length of the level bubble 22 is 24 mm, the diameter of the blind hole 24 is 6.6 mm, and the depth of the blind hole 24 is 52 mm.

[0027] A positioning ring 15 is provided on the outer wall of the elongated positioning block 14. The positioning ring 15 is integrally formed with the elongated positioning block 14. The outer diameter of the positioning ring 15 is larger than the inner diameter of the furnace tube 1. The positioning ring 15 is used to limit the length of the elongated positioning block 14 inserted into the furnace tube 1 when in use.

[0028] The telescopic support mechanism includes a telescopic outer cylinder 8, a clamping plate 9, a telescopic adjustment rod 10, an adjustment ring 11 and a V-shaped bracket 12. The telescopic outer cylinder 8 is fixed on the support base 7. Several clamping plates 9 are provided. Several clamping plates 9 are fixed to the upper end of the telescopic outer cylinder 8. The lower end of the telescopic adjustment rod 10 extends into the telescopic outer cylinder 8. The upper end of the telescopic adjustment rod 10 is fixedly connected to the lower end of the V-shaped bracket 12. The adjusting ring 11 is sleeved on the telescopic outer cylinder 8. Several clamping plates 9 are threadedly connected to the adjusting ring 11. When in use, the adjusting ring 11 is loosened and the height of the V-shaped bracket 12 is adjusted. After the position is determined, the adjusting ring 11 can be rotated. At this time, the V-shaped bracket 12 is used to support the horizontal positioning block 13 so that the central axis of the horizontal positioning block 13 and the long positioning block 14 coincides with the central axis of the furnace tube 1;

[0029] The long positioning block 14 is made of mullite, high-alumina brick or corundum; the horizontal positioning block 13 is made of transparent materials such as quartz glass, ordinary glass, or can be made of metal iron, aluminum, copper, steel or corundum; the connecting bolt 16 is made of stainless steel or corundum, and the V-shaped bracket 12 is made of aluminum alloy or stainless steel, which is light in weight and can withstand a certain high temperature.

[0030] The present invention effectively improves the test results of the temperature field of the cheap metal thermocouple calibration furnace. Compared with the case where the embodiment of the present invention is not adopted, under the conditions of the first embodiment of the present invention, the axial temperature difference within 30 mm of the laboratory cheap metal thermocouple calibration furnace is measured to be reduced by 0.05°C, and the radial temperature difference of the axial center section (i.e., the inner bottom surface of the cup-type temperature equalizing block 3) is reduced by 0.02°C.

[0031] Example 2

[0032] See also Figure 8 The difference from the first embodiment is that a plurality of blind grooves 21 are opened on the horizontal positioning block 13, and the plurality of blind grooves 21 are distributed in a circular array. There are at least three blind grooves 21, and the shape of the horizontal bubble 22 is cylindrical or rectangular, and the corresponding blind grooves 21 are semicircular or rectangular.

[0033] Working principle: When in use, the connecting bolt 16 is used to pass through the connecting through hole 18 and the connecting through hole 2 23 in sequence, thereby connecting the long positioning block 14 and the horizontal positioning block 13, and the test positioning tube 5 is placed in the positioning tube hole 17. The test standard pair 6 is passed through the right end of the standard pair hole 2 20, and sequentially passes through the standard pair hole 20 and the standard pair hole 1 19 to extend into the test positioning tube 5, and the left end of the long positioning block 14 is inserted into the furnace tube 1; the long positioning block 14 is provided in the device, which increases the constraint length of the position of the test standard pair 6, reduces the deflection of the test standard pair 6 caused by the clearance between the opening of the measuring end positioning block 4 and the test positioning tube 5, and does not cause additional significant interference to the temperature field in the furnace; According to the height of the horizontal positioning block 13, the telescopic support mechanism is used to support the horizontal positioning block 13. When adjusting, the adjustment ring 11 is loosened and the height of the V-shaped bracket 12 is adjusted. After the position is determined, the adjustment ring 11 can be rotated. At this time, the V-shaped bracket 12 is used to support the horizontal positioning block 13 so that the central axis of the horizontal positioning block 13 and the long positioning block 14 coincides with the central axis of the furnace tube 1; the level bubble 22 is placed in the blind groove 21, and the level bubble 22 is used to provide a "ruler" for the test standard couple 6 to be parallel to the central axis of the furnace tube 1. This device reduces the uncertainty of the calibration furnace temperature field test results caused by the position deviation of the standard couple temperature measuring point, and can more accurately test, characterize and evaluate the temperature field of the low-cost metal thermocouple calibration furnace.

[0034] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An off-furnace positioner for temperature field testing of a low-cost metal thermocouple calibration furnace, comprising a support base (7), connecting bolts (16), a horizontal positioning block (13) and a long positioning block (14), characterized in that: The horizontal positioning block (13) and the long positioning block (14) have the same outer diameter. The left end of the long positioning block (14) is inserted into the furnace tube (1) of the low-cost metal thermocouple calibration furnace. The horizontal positioning block (13) is located above the support base (7). A telescopic support mechanism is provided between the support base (7) and the horizontal positioning block (13). The long positioning block (14) is located on the left side of the horizontal positioning block (13). Two connecting through holes are provided on the long positioning block (14). One (18), two connecting through holes (23) are provided on the horizontal positioning block (13), the connecting through hole (18) and the connecting through hole (23) are coaxially arranged, the right end of the connecting bolt (16) passes through the connecting through hole (18) and the connecting through hole (23) in sequence and is connected with a nut, the left end of the elongated positioning block (14) is provided with two positioning tube holes (17), one of the positioning tube holes (17) is coaxially arranged with the elongated positioning block (14), the elongated positioning block (14) is provided with a plurality of positioning tube holes (17), and the elongated positioning block (14) is provided with a plurality of positioning tube holes (17). The right side of the type positioning block (14) is provided with two standard even holes (19), the two standard even holes (19) are respectively connected to the two positioning tube holes (17), the inner diameter of the positioning tube hole (17) is larger than the inner diameter of the standard even hole (19), the horizontal positioning block (13) is provided with two standard even holes (20), the two standard even holes (19) are respectively coaxially arranged with the two standard even holes (20), the standard even hole (19) and the standard even hole (20) are respectively coaxially arranged. (20) are of the same size, a blind hole (24) is provided at the right end of the horizontal positioning block (13), a horizontal bubble (22) is provided in the blind hole (24), the central axis of the blind hole (24) is parallel to the central axis of the horizontal positioning block (13), a positioning ring (15) is provided on the outer wall of the elongated positioning block (14), the positioning ring (15) and the elongated positioning block (14) are integrally formed, and the outer diameter of the positioning ring (15) is larger than the outer diameter of the elongated positioning block (14); The telescopic support mechanism comprises a telescopic outer cylinder (8), a clamping plate (9), a telescopic adjustment rod (10), an adjustment ring (11) and a V-shaped bracket (12).

2. The external positioner for temperature field testing of a low-cost metal thermocouple calibration furnace according to claim 1, characterized in that: A plurality of blind grooves (21) are provided on the outer side wall of the horizontal positioning block (13), and there are at least three blind grooves (21). The central axis of the blind groove (21) is parallel to the central axis of the horizontal positioning block (13).

3. The external positioner for temperature field testing of a low-cost metal thermocouple calibration furnace according to claim 1, characterized in that: The telescopic outer cylinder (8) is fixed on the supporting base (7), and a plurality of clamping plates (9) are provided. The plurality of clamping plates (9) are fixed on the upper end of the telescopic outer cylinder (8). The lower end of the telescopic adjustment rod (10) extends into the telescopic outer cylinder (8). The upper end of the telescopic adjustment rod (10) is fixedly connected to the lower end of the V-shaped bracket (12). The adjustment ring (11) is sleeved on the telescopic outer cylinder (8), and the plurality of clamping plates (9) are threadedly connected to the adjustment ring (11).

4. The external positioner for temperature field testing of a low-cost metal thermocouple calibration furnace according to claim 1, characterized in that: The long positioning block (14) is made of mullite, high-alumina brick or corundum; the horizontal positioning block (13) is made of transparent materials such as quartz glass, ordinary glass, etc., and can also be made of metal iron, aluminum, copper, steel or corundum; the connecting bolt (16) is made of stainless steel or corundum, and the V-shaped bracket (12) is made of aluminum alloy or stainless steel.

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