TWI727863B - Energy-saving device for radiant tube heater - Google Patents

Abstract

An energy-saving device for a radiant tube heater, suitable for being inserted in an exhaust straight pipe section of a radiant tube, and comprising a plurality of arcs arranged along the axial direction of one of the exhaust straight pipe sections The plate unit, wherein each arc-shaped plate unit includes a first arc-shaped plate, the first arc-shaped plate is axially extending along an arc-shaped plate perpendicular to the axial direction of the exhaust straight pipe section, and has two parallel A first end surface in the axial direction of the arc-shaped plate, and a first arc-shaped plate body extending between the first end surfaces and defining a first cavity. Wherein, when the gas flows through the straight exhaust pipe section, a vortex will be generated inside the first cavities, and the gas flow will be compressed and accelerated by the arc-shaped plate units, thereby enhancing the gas flow in the Convective heat transfer inside the exhaust straight pipe section.

Description

Energy-saving device for radiant tube heater

The present invention relates to an energy-saving device, in particular to an energy-saving device for a radiant tube heater.

Radiant tube devices are often used in the heating process in the industry to introduce high-temperature gas into the radiant tube to heat the radiant tube, and then the high-temperature radiant tube uses radiant heat transfer to the product objects (ie loads, such as steel belts in steel plants, etc...) , In order to achieve the purpose of uniform heating of the product objects. In addition, a radiant tube insert (RTI) can be inserted into the straight section of the exhaust pipe of the radiant tube as an energy-saving device, which can enhance the heat transfer of high-temperature gas to the wall of the radiant tube to improve the heating efficiency. Save fuel.

U.S. Patent No. US20150079529A1 was filed by PSNergy. It mainly discloses an insert for the radiant tube of a heating furnace, which includes: a first part for absorbing the heat of the gas flowing through the radiant tube, and the heat Radiant heat is transferred to the tube wall of the radiant tube; and a second part for guiding the heat and gas in the radiant tube to the first part. However, the US20150079529A1 published patent case has two shortcomings: (1) The commercial product has a complicated structure and high cost; (2) After the applicant of the present invention, China Iron and Steel Corporation, was used on site, damage occurred in less than three years, including: The alignment latch is broken, the airfoil structure (that is, the second part) is broken, and the radiating surface structure is damaged. After the structure is broken, the heat transfer enhancement function of the RTI cannot be fully exerted.

The US Pat. No. 6,484,795 mainly discloses that a helical insert made of ceramic material is installed at the flame end of the radiant tube burner to enhance the convective heat transfer to the inner wall of the tube through the swirling of the airflow. However, the RTI disclosed in the US6484795 publication patent is non-directional heating, which simultaneously heats the non-demand surface in the radiant tube, which will increase energy consumption. Secondly, the commercial material of the US6484795 Announcement Patent Case is silicon carbide (SiC). Under the environment where the annealing furnace of the applicant, China Iron and Steel Company, uses coke oven gas (COG) gas, it will be compatible with the aforementioned US20150079529A1 patent case. Damage to the same product.

China's CN2245759Y Announcement Patent Case mainly discloses that a twisted band insert is inserted into the body of the radiant tube. The twisted ribbon insert is a flat ribbon that has been twisted, and the airflow can rotate along the spiral twisted ribbon in the radiant tube, and can strengthen the convective heat transfer of the airflow to the tube wall, thereby enhancing the overall heat transfer coefficient. However, the RTI disclosed in the CN2245759Y patent case is non-directional heating, which simultaneously heats the non-demand surface in the radiant tube, which will increase energy consumption. Secondly, the hot gas flows in the radiant tube in a rotary heat mode, so the flow resistance is relatively large.

Therefore, in view of the above-mentioned shortcomings of the above-mentioned conventional RTI, it is necessary to seek a solution.

Therefore, the purpose of the present invention is to provide an energy-saving device for the radiant tube heater.

Therefore, the energy-saving device for the radiant tube heater of the present invention is suitable for being inserted in an exhaust straight pipe section of a radiant tube, and includes a plurality of exhaust straight pipe sections arranged axially along one of the exhaust straight pipe sections The arc-shaped plate unit, wherein each arc-shaped plate unit includes a first arc-shaped plate that extends axially along an arc-shaped plate perpendicular to the axial direction of the exhaust straight pipe section, and It has two first end surfaces parallel to the axial direction of the arc-shaped plate, and a first arc-shaped plate body extending between the first end surfaces and defining a first cavity. Wherein, when the gas flows through the straight exhaust pipe section, a vortex will be generated inside the first cavities, and the gas flow will be compressed and accelerated by the arc-shaped plate units, thereby enhancing the gas flow in the Convective heat transfer inside the exhaust straight pipe section.

The effect of the present invention is that the structure of the arc-shaped plate units arranged along the axial direction of the exhaust straight pipe section is greatly simplified, so the production cost is greatly reduced. Among them, when the gas flows through the exhaust straight pipe section, the arc plate units A vortex will be generated inside the shaped plate unit, and the gas flow will be compressed and accelerated by the arc shaped plate units, so that the convective heat transfer of the gas inside the straight exhaust pipe section can be enhanced.

1 to 4, the first embodiment of the energy-saving device 2 (ie, radiant tube insert, hereinafter referred to as RTI) for a radiant tube heater according to the present invention is suitable for being inserted in an exhaust straight pipe section of a radiant tube 1 14, wherein the radiant tube 1 is used to radiately heat a load 9 (such as a steel belt, etc.) conveyed along a conveying direction 91.

In the first embodiment, the energy-saving device 2 for a radiant tube heater includes a plurality of arc-shaped plate units 20 arranged along the axial direction A of one of the straight exhaust pipe sections 14, as shown in the figure, for example The five arc-shaped plate units 20 shown in 1, 4, wherein the arc-shaped plate units 20 are made of materials such as nickel-based alloys. In the first embodiment, the arc-shaped plate units 20 used as RTIs are made of undamaged pipe sections of radiant tubes that are self-eliminated. They are made of nickel-based alloys, which are better than those in a coke oven gas (COG) gas environment. Commercial RTI material silicon carbide (SiC) is more durable.

As shown in FIGS. 1, 2, and 3, each arc-shaped plate unit 20 includes a first arc-shaped plate 21 and a second arc-shaped plate 22 facing the first arc-shaped plate 21. In the first embodiment, the first arc-shaped plate 21 extends along an arc-shaped plate axis B perpendicular to the axial direction A of the exhaust straight pipe section, and has two arc-shaped plate axes B parallel to the axial direction A of the exhaust straight pipe section. The first end surface 211 and a first arc-shaped plate 212 extending between the first end surfaces 211 and defining a first cavity 214.

In the same way, the second arc-shaped plate 22 also extends along the arc-shaped plate axial direction B, and has two second end surfaces 221 parallel to the arc-shaped plate axial direction B, and one extending on the second end surfaces A second arc-shaped plate 222 with a second cavity 224 is defined between 221.

In the first embodiment, the cross-sectional shape of each first arc-shaped plate body 212 and each second arc-shaped plate body 222 are generally arcs with an angle less than 180 degrees.

In the first embodiment, each first arc-shaped plate 21 defines a first engaging groove 213 adjacent to the first end surfaces 211, and each second arc-shaped plate 22 is adjacent to the second Each of the end surfaces 221 defines a second insertion groove 223. Wherein, the first engaging grooves 213 of each first arc-shaped plate 21 are respectively engaged with the second engaging grooves 223 of the corresponding second arc-shaped plate 22, so that each second arc The shaped plate 22 can be firmly joined with the corresponding first arc shaped plate 21 up and down, as shown in FIG. 3.

Therefore, as shown in FIGS. 1 and 3, in the first embodiment, when the gas 10 flows through the straight exhaust pipe section 14, the arc-shaped plates arranged along the axial direction A of the straight exhaust pipe section The first cavity 214 and the second cavity 224 of the unit 20 will generate a vortex, and the airflow of the gas 10 will be compressed and accelerated by the arc-shaped plate units 20, thereby enhancing the gas 10 Convective heat transfer inside the straight exhaust pipe section 14.

Referring to Figures 5 and 6, in the second embodiment of the energy-saving device 2 for a radiant tube heater of the present invention, the second arc-shaped plates 22 in the first embodiment do not need to be used, but only the The first arc-shaped plate 21, and the adjacent two of the first arc-shaped plates 21 arranged along the axial direction A of the exhaust straight pipe section can be firmly secured by the first fitting grooves 213 Fit together. Therefore, when the energy-saving device 2 for a radiant tube heater of the second embodiment is inserted into the exhaust straight pipe section 14 of FIG. 1 and the gas 10 flows through the exhaust straight pipe section 14, the first air A vortex will be generated inside the cavity 214, and the airflow of the gas 10 will be compressed and accelerated by the energy-saving device 2 for a radiant tube heater, thereby enhancing the convective heat transfer of the gas 10 inside the exhaust straight pipe section 14. .

Referring to Figures 4, 5, 7 to 30, the first embodiment shown in Figure 4 above can provide a vertical annealing furnace application. In the following experimental statistical charts and computational fluid dynamics (CFD) statistical charts in Figures 8 to 30, The radiant tube insert (RTI) of the first embodiment will be referred to as China Iron and Steel Corporation (ie the applicant of the present invention, CSC for short) (I) RTI; and the second embodiment shown in Figure 5 above can provide a level For the application of an annealing furnace, the RTI of the second embodiment will be referred to as CSC(II)RTI in the experimental statistical graphs and CFD statistical graphs shown in Figures 8 to 30 below.

As shown in Figures 7 and 8, it is set at 750℃, 800℃, 850℃ and 900℃ and other commonly used furnace temperature range conditions in the field of steel plants, using CSC(I)RTI (i.e. the first embodiment) and CSC(II)RTI (the second embodiment), and without using the RTI energy-saving device, carry out the radiant tube surface temperature distribution experiment, and obtain the comparison chart of the radiant tube surface temperature distribution of the experimental results in Fig.8. 7 shows that the W-shaped radiant tube 1 includes a first straight pipe section 11 from upstream to downstream, a first U-shaped pipe section 15, a second straight pipe section 12, a second U-shaped pipe section 16, and a third straight pipe section 13, The third U-shaped pipe section 17 and the fourth straight pipe section 14 (or called the exhaust straight pipe section 14), and the abscissa of Figure 8 represents the distance from the inlet to the outlet of the W-shaped radiant tube 1 from the gas 10, and there are three different line types Respectively represent the experimental results of using CSC(I)RTI, bare tube and using CSC(II)RTI.

The experimental results in Fig. 8 show that the radiant tube 1 is installed with the first and second embodiments of the energy-saving device 2 for radiant tube heaters of the present invention. Under various furnace temperature conditions, it is shown that the radiant tube 1 has RTI installed The pipe wall of the fourth straight pipe section 14 has a significant temperature increase effect (as shown in the fourth straight pipe section data 140), while the third straight pipe section 13 also has a slight temperature increase, while the other pipe sections have no obvious temperature rise. In addition, the CSC(I)RTI of the first embodiment is better than the CSC(II)RTI of the second embodiment in raising the tube wall temperature. It can make the tube wall of the fourth straight pipe section 14 at a furnace temperature of 900°C. The temperature is increased by an average of 40℃, and the temperature can be increased by lower furnace temperature conditions. According to the theory of radiant heat transfer, the increased temperature can increase the radiant heat by about 11%.

As shown in Figure 9, after comparing the performance of the conventional commercial PSN RTI sold by PSNergy, the conventional commercial SP RTI sold by SPIN-WORKS, CSC(I)RTI and CSC(II)RTI, the performances of various RTIs in different shapes are compared by The exhaust gas temperature measured after the reheater (not shown in the figure) shows that after installing RTI, the exhaust gas temperature drops significantly. Taking the installation of CSC(I)RTI as an example, when the furnace temperature is 900°C, the exhaust gas temperature drops by 20°C. From the energy balance relationship, it can be seen that under the condition that the fuel quantity at the inlet of the radiant tube 1 is the same, the temperature of the radiant tube 1 The lower the temperature of the exhaust gas discharged from the outlet, the more heat remains in the heating furnace, which indirectly proves that the energy-saving device 2 for the radiant tube heater of the present invention has the effect of enhancing heat transfer.

Next, as shown in Figure 10, the effect of using various RTIs on the efficiency of the heating furnace is analyzed. The results show that the use of various RTIs can improve the heating efficiency while maintaining the furnace temperature. Among them, the CSC(I)RTI of the first embodiment of the present invention is the best. At a furnace temperature of 900°C, the heating efficiency of the radiant tube 1 can be increased from 42% to 43.5%, which can be increased by 1.5%. Although the heating efficiency of the CSC(II)RTI in the second embodiment is not as good as that of the CSC(I)RTI, it is still similar to conventional commercial products. As shown in Table 1 below, at a furnace temperature of 900°C, the fuel saving rates of CSC(I)RTI and CSC(II)RTI can reach approximately 3.6% and 1.6%, respectively.

Table 1. Comparison of fuel saving rate (=(η1/η2)-1.0): Furnace temperature (℃) Bare tube PSN RTI SP RTI CSC(I) RTI CSC(II) RTI 750 - -1.88% -2.5% -4.4% -2.9% 800 - -0.17% -1.5% -3.9% -1.8% 850 - -0.36% -2.6% -3.4% -1.4% 900 - -0.54% -2.1% -3.6% -1.6%

As shown in Figures 11 to 15, then, using computational fluid dynamics (CFD) software simulation analysis, at a furnace temperature of 900 ℃, compare the installation of the CSC (I) RTI and CSC (II) RTI of the present invention and the conventional commercial RTI The heat transfer enhancement effect of the radiant tube 1. Comparing the simulation results of the flow field in Figs. 11-15, it can be seen that the structure of the gas streamline is similar to the first three straight pipe sections, and the significant difference is in the fourth straight pipe section 14. When RTI is installed (Fig. 11 to 14). The streamlines in the fourth straight pipe section 14 present a turbulent distribution. As shown in FIG. 11, in the CSC(I)RTI of the first embodiment of the present invention, due to the special design of the first cavities 214 and the second cavities 224, eddy currents are generated inside the fourth straight pipe section 14. At the same time, the airflow of the gas 10 is compressed when passing through the cross-sectional area of the arc-shaped plate units 20, so the flow of the gas 10 can be accelerated and the convective heat transfer of the gas 10 inside the straight exhaust pipe section 14 can be enhanced. Similarly, as shown in FIG. 12, due to the special design of the first cavities 214 in the CSC(II)RTI of the second embodiment of the present invention, a vortex is generated inside the fourth straight pipe section 14, and at the same time, the gas 10 The air flow is compressed when passing through the cross-sectional area of the arc-shaped plate units 20, so the flow of the gas 10 can be accelerated and the convective heat transfer of the gas 10 inside the straight exhaust pipe section 14 can be enhanced.

The results of CFD simulation of the pressure field distribution in the radiant tube 1 as shown in Figures 16 to 20 show that after the gas 10 flows through the first U-shaped pipe section 15, the second U-shaped pipe section 16, and the third U-shaped pipe section 17, Local low pressure areas are generated on the inner side, and there is also a significant pressure drop. The pressure gradation difference in Figures 16 to 20 shows that the maximum pressure drop occurs in the region of the fourth straight pipe section 14. Generally speaking, the fourth straight pipe section 14 will increase by 40~140Pa compared with the bare pipe after RTI is installed. Among them, when using CSC(I)RTI, the largest pressure loss will occur, up to 200Pa.

In addition, the results of CFD simulation of the tube wall temperature distribution of the radiant tube 1 as shown in FIGS. 21 to 25 show that the temperature of the fourth straight tube section 14 is significantly increased due to the RTI inserted in the fourth straight tube section 14. As for the CFD simulation results of the temperature distribution of the gas 10 in the radiant tube 1, the results are shown in Figs. 26-30.

Furthermore, the results of the heat flow field of the radiant tube 1 when the RTIs of different shapes are installed in the above-mentioned FIGS. 11 to 30 can be obtained in Table 2 below. It can be seen from Table 2 that CSC(I)RTI has the best heat transfer effect, which can increase the heating efficiency of bare tubes by 3.2%, while CSC(II)RTI is similar to PSN RTI. As for the pressure loss of the fourth straight pipe section 14 caused by the installation of the energy-saving device 2 for the radiant tube heater of the present invention, in the case of the CSC(I)RTI of the first embodiment, the pressure loss increased by up to 140 Pa (≒205.9 Pa-64.6 Pa), which is 13.5mmAq, and the gas and air pressure provided by the on-site utility pipelines of the applicant, China Iron and Steel Company, reached 5 kg/cm ² (5×10 ⁴ mmAq) and 6 kg/cm ² (6×10 ⁴ mmAq) or more, so it should be sufficient to overcome the increased pressure loss.

Table 2. Simulation and comparison of the results of installing different RTIs DP (Pa) Heat supply to load (kW) RTI enhanced radiant heat (kW) RTI enhanced convective heat (kW) Average temperature of energy-saving device (℃) Exhaust temperature (℃) Heating efficiency (%) Bare tube 64.6 55.2 - - - 1208.2 20.9 CSC(I)RTI 205.9 62.9 5.95 1.73 1031.7 1148.2 24.1 CSC(II)RTI 200.8 62.0 4.07 2.77 1024.6 1154.8 23.8 PSN RTI 146.3 61.9 4.94 1.73 1030.9 1156.1 23.7 SP RTI 135.8 61.2 3.66 2.37 1016.1 1161.2 23.4

In summary, the energy-saving device 2 for a radiant tube heater of the present invention has at least the following advantages and functions: (1) The structure of the arc-shaped plate units 20 arranged along the axial direction A of the exhaust straight pipe section It is greatly simplified, so the production cost is greatly reduced; (2) The first embodiment is particularly suitable for assembly in a vertical annealing furnace. When the gas 10 flows through the exhaust straight pipe section 14, the arc-shaped plate units 20 The first cavity 214 and the second cavity 224 will generate vortex, and the gas flow of the gas 10 will be compressed and accelerated by the arc-shaped plate units 20, thereby enhancing the gas 10 in the The convective heat transfer inside the straight exhaust pipe section 14; (3) The second embodiment is particularly suitable for assembly in a horizontal annealing furnace. When the gas 10 flows through the straight exhaust pipe section 14, the arc-shaped plates The first cavity 214 of the unit 20 will generate a vortex, and the airflow of the gas 10 will be compressed and accelerated by the arc-shaped plate units 20, thereby enhancing the gas 10 in the exhaust straight pipe section 14 The convective heat transfer; (4) The arc-shaped plate units 20 are made of undamaged pipe sections of radiant tubes that are eliminated from the elimination. The material is nickel-based alloy, which is better than that of commercial RTI in the coke oven gas (COG) gas environment. The material silicon carbide (SiC) is more durable; it can indeed achieve the purpose of the invention.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the patent specification still belong to Within the scope covered by the patent of the present invention.

1: radiant tube 10: Gas 11: The first straight pipe section 12: The second straight pipe section 13: The third straight pipe section 14: The fourth straight pipe section or exhaust straight pipe section 140: The fourth straight pipe section data 15: The first U-shaped pipe section 16: The second U-shaped pipe section 17: The third U-shaped pipe section 2: Energy-saving device for radiant tube heater 20: Curved plate unit 21: The first curved plate 211: first end face 212: The first arc plate body 213: The first fitting groove 214: The First Hole 22: The second curved plate 221: second end face 222: second curved plate body 223: second fitting groove 224: The Second Hole 9: load 91: Conveying direction A: Exhaust straight pipe section axial B: Axial of curved plate

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: Figure 1 is a perspective view illustrating the first embodiment of the energy-saving device for a radiant tube heater of the present invention; Figure 2 is a perspective view illustrating the first and second arc-shaped plates in the first embodiment; Fig. 3 is a perspective view illustrating that the first arc-shaped plate and the second arc-shaped plate are joined to form an arc-shaped plate unit in the first embodiment; Figure 4 is a perspective view illustrating that five arc-shaped plate units are arranged to form the energy-saving device for a radiant tube heater in the first embodiment; Figure 5 is a perspective view illustrating a second embodiment of the energy-saving device for a radiant tube heater of the present invention; Figure 6 is a side view illustrating the second embodiment; Figure 7 is a top view illustrating that the energy-saving devices of the first and second embodiments are inserted into a W-shaped radiant tube; FIG. 8 is a temperature distribution diagram illustrating the comparison diagram of the surface temperature distribution of the radiant tube under the three cases of using the first embodiment, the second embodiment, and not using the energy-saving device; Figure 9 is a temperature distribution diagram illustrating a comparison diagram of exhaust gas temperature under test furnace temperature conditions with different RTIs installed in the radiant tube; Figure 10 is a comparison diagram of the efficiency of the heating furnace, illustrating the effect of installing different RTIs in the radiant tube on the efficiency of the heating furnace; Figure 11 is a flow line distribution diagram, illustrating the use of computational fluid dynamics (CFD) software to simulate the installation of China Iron and Steel Corporation (namely the applicant of the present invention, CSC for short) (I) radiant tube insert (RTI) (namely the above-mentioned first Example) the velocity streamline distribution results; Figure 12 is a flow line distribution diagram, illustrating the results of the velocity flow line distribution of the CSC(II) RTI installed in the radiant tube simulated by CFD software (i.e., the second embodiment above); Figure 13 is a flow line distribution diagram, illustrating the results of the velocity and streamline distribution of the commercial PSN RTI sold by PSNergy in the radiant tube simulated by CFD software; Figure 14 is a flow line distribution diagram, illustrating the results of the velocity streamline distribution of the commercial SP RTI sold by the conventional SPIN-WORKS company installed in the radiant tube simulated by CFD software; Figure 15 is a flow line distribution diagram, illustrating the result of using CFD software to simulate the velocity streamline distribution in the radiant tube without installing RTI; Figure 16 is a pressure distribution diagram illustrating the results of simulating the pressure distribution of CSC(I) RTI installed in a radiant tube with CFD software; Figure 17 is a pressure distribution diagram illustrating the results of simulating the pressure distribution of CSC(II) RTI installed in a radiant tube with CFD software; Figure 18 is a pressure distribution diagram illustrating the results of using CFD software to simulate the pressure distribution of a conventional commercial PSN RTI installed in a radiant tube; Figure 19 is a pressure distribution diagram illustrating the results of using CFD software to simulate the pressure distribution of a conventional commercial SP RTI installed in a radiant tube; Figure 20 is a pressure distribution diagram illustrating the results of using CFD software to simulate the pressure distribution in the radiant tube without installing RTI; Figure 21 is a temperature distribution diagram illustrating the results of simulating the wall temperature distribution of the radiant tube with CSC(I) RTI installed in the radiant tube by CFD software; Figure 22 is a temperature distribution diagram illustrating the results of simulating the wall temperature distribution of the radiant tube with CSC(II) RTI installed in the radiant tube by CFD software; Figure 23 is a temperature distribution diagram illustrating the results of simulating the wall temperature distribution of the radiant tube with the conventional commercial PSN RTI installed in the radiant tube by CFD software; Figure 24 is a temperature distribution diagram illustrating the results of using CFD software to simulate the temperature distribution of the radiant tube wall of the radiant tube installed in the conventional commercial SP RTI; Figure 25 is a temperature distribution diagram illustrating the results of using CFD software to simulate the temperature distribution of the radiant tube wall without RTI installed in the radiant tube; Figure 26 is a temperature distribution diagram illustrating the results of using CFD software to simulate the gas temperature distribution in the radiant tube with CSC(I) RTI installed in the radiant tube; Figure 27 is a temperature distribution diagram illustrating the results of using CFD software to simulate the gas temperature distribution in the radiant tube with CSC(II) RTI installed in the radiant tube; Figure 28 is a temperature distribution diagram illustrating the results of using CFD software to simulate the gas temperature distribution in the radiant tube installed in the conventional commercial PSN RTI; Figure 29 is a temperature distribution diagram illustrating the results of using CFD software to simulate the gas temperature distribution in the radiant tube installed with a conventional commercial SP RTI; and Figure 30 is a temperature distribution diagram illustrating the results of using CFD software to simulate the gas temperature distribution in the radiant tube without RTI installed.

1: radiant tube

10: Gas

14: Exhaust straight pipe section

2: Energy-saving device for radiant tube heater

20: Curved plate unit

9: load

91: Conveying direction

A: Exhaust straight pipe section axial

Claims (7)

An energy-saving device for a radiant tube heater, suitable for being inserted in an exhaust straight pipe section of a radiant tube, and containing: A plurality of arc-shaped plate units arranged axially along one of the straight exhaust pipe sections, wherein each arc-shaped plate unit includes a first arc-shaped plate, and the first arc-shaped plate is along a The arc-shaped plate perpendicular to the axial direction of the exhaust straight pipe section extends axially, and has two first end surfaces parallel to the axial direction of the arc-shaped plate, and a first end surface extending between the first end surfaces and defining a first space The first arc-shaped plate of the cavity; Wherein, when the gas flows through the straight exhaust pipe section, a vortex will be generated inside the first cavities, and the gas flow will be compressed and accelerated by the arc-shaped plate units, thereby enhancing the gas flow in the Convective heat transfer inside the exhaust straight pipe section. The energy-saving device for a radiant tube heater according to claim 1, wherein the arc-shaped plate units are made of nickel-based alloy. The energy-saving device for a radiant tube heater according to claim 1, wherein the cross-sectional shape of each first arc-shaped plate body is generally an arc with an angle less than 180 degrees. The energy-saving device for a radiant tube heater according to claim 1, wherein each of the first arc-shaped plates defines a first fitting groove adjacent to the first end faces, and the first fitting grooves are inserted into the exhaust Adjacent two of the first arc-shaped plates in the straight pipe section and axially arranged along the exhaust straight pipe section are firmly fitted together by the first fitting grooves. The energy-saving device for a radiant tube heater according to claim 1, wherein each arc-shaped plate unit further includes a second arc-shaped plate, and the second arc-shaped plate is along the straight line perpendicular to the exhaust gas. The arc-shaped plate in the axial direction of the pipe section extends axially, and has two second end surfaces parallel to the axial direction of the arc-shaped plate, and a second arc extending between the second end surfaces and defining a second cavity Plate body, wherein each second arc-shaped plate is opposed to the corresponding first arc-shaped plate, so that when the gas flows through the exhaust straight pipe section, the first cavities and the second cavities A vortex will be generated inside, and the gas flow will be compressed and accelerated by the arc-shaped plate units, thereby enhancing convective heat transfer. The energy-saving device for a radiant tube heater according to claim 5, wherein the cross-sectional shape of each second arc-shaped plate body is generally an arc with an angle less than 180 degrees. The energy-saving device for a radiant tube heater according to claim 5, wherein each first arc-shaped plate defines a first fitting groove adjacent to the first end faces, and each second arc-shaped Each of the plates defines a second insertion groove adjacent to the second end surfaces, wherein the first insertion grooves of each first arc-shaped plate are respectively corresponding to the second insertion grooves of the corresponding second arc-shaped plate The fitting grooves are fitted together, so that each second arc-shaped plate and the corresponding first arc-shaped plate can be firmly joined together.

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