TWI616620B - Radiant tube device - Google Patents

Abstract

A radiant tube device includes a draft tube defining a conductive space extending in a gas flow direction, and a plurality of inserts aligned in the flow direction along the flow direction. Each of the inserts includes a curved arc-shaped plate body, two inner guide piece portions disposed on the inner curved surface of the plate body, and two outer guide piece portions disposed on the outer curved surface of the plate body. The plate body has an upstream end edge, a downstream end edge opposite to the upstream end edge, and two engaging edges respectively connected to the upstream end edge and the opposite end of the downstream end edge, the radius of curvature of the upstream end edge being greater than the downstream End side. The inner guide piece and the outer guide piece are respectively spaced apart to define a front opening and a rear opening, and the front opening is smaller than the rear opening. The inserts direct the flow of gas and optimize the heat flow characteristics of the radiant tube assembly.

Description

Radiant tube device

The present invention relates to a heat transfer device for an industrial heating process, and more particularly to a radiant tube device.

Referring to Figure 1, there is shown a prior art radiant tube 10, and a plurality of inserts 1 disposed in the radiant tube 10. The radiant tube 10 is used to introduce high-heat gas, and the inserts 1 can change the flow of the gas, increase the heat transfer of the gas to the radiant tube 10, thereby improving the heating efficiency. Each of the inserts 1 includes a base pipe portion 11 and two extending walls 12 extending away from the base pipe portion 11 at an angle, engaging an extension wall 12 and surrounding the extension wall 12 The curved wall 13 of the passage 123, a plurality of radiating members 14 protruding from the curved wall 13 (only one can be seen in FIG. 1), and two fins 15 connected to the draft tube 11. However, although the radiant tube 10 can transmit thermal energy in a radiative manner to achieve uniform heat transfer, the structure of the fins 15 is complicated by the complicated structure of the insert 1 due to the complicated structure of the insert 1 . Design flaws also cause convection in some of the heat, thus affecting the function of radiant heat transfer.

Referring to FIG. 2, a conventional radiant tube 2 includes a U-shaped draft tube 21 communicating at both ends, a burner 22 disposed at one end of the U-shaped draft tube 21, and a U-shaped diversion flow. a heat exchanger 23 disposed at the other end of the tube 21, and a twisted belt insert disposed in the U-shaped draft tube 21 and located between the burner 22 and the heat exchanger 23 and having a helical twist shape twenty four. The thermal energy generated by the combustor 22 enhances the flow of gas through the twisted band insert 24, enhancing heat transfer to the U-shaped draft tube 21, thereby enhancing the overall heat transfer coefficient of the radiant tube 2. However, since hot gas flows along the twisted-band insert 24, it flows in a spiral, and thus a relatively large flow resistance is generated, thereby affecting efficiency. In addition, in the U-shaped U-shaped draft tube 21, a part of the outer surface of the tube wall faces the outer surface of the other part of the tube wall, and it is easy to absorb the heat energy radiated by itself, thereby increasing the heat consumption and being difficult to be specific to The object is heated in a targeted manner.

The design of the radiant tube 2 as shown in Fig. 2, while improving the structural complexity of the insert 1 of the radiant tube 10 as shown in Fig. 1, also causes flow resistance problems due to the structure of the twisted strip insert 24. Therefore, how to balance the overall shape of the inserted components and optimize the heating efficiency, and to generate directional heating, has become a key point for the research and development of the related fields.

Accordingly, it is an object of the present invention to provide a radiant tube device which is excellent in appearance, heating efficiency, and heat transfer property, and which is capable of achieving directional heating.

Thus, the radiant tube device of the present invention comprises a draft tube defining a conductive space extending in a flow direction of gas conduction, and a plurality of inserts disposed in the conductive space and arranged in the flow direction. .

Each of the inserts includes a plate body having a curved shape, two inner guide portions, and two outer guide portions. The plate body has an inner arc surface, an outer arc surface opposite to the inner arc surface, an upstream end edge, a downstream end edge opposite to the upstream end edge, and two respectively connected to the upstream end edge and the a connecting edge of opposite ends of the downstream end, wherein a radius of curvature of the upstream end is greater than a radius of curvature of the downstream end.

The inner guiding piece portions extend obliquely from the inner arc surface of the plate body toward each other, and extend obliquely in the flow direction away from each other, and the front end portions of the inner guiding piece portions define an inner front opening, and then The end spacing defines an inner rear port that is smaller than the inner rear port.

The outer guiding piece portions extend obliquely away from each other from the outer arc surface of the plate body, and extend obliquely in the flow direction away from each other, and the front end portions of the outer guiding piece portions define an outer front opening, and then The end spacing defines an outer rear port that is smaller than the outer rear port.

The effect of the invention is that when the gas introduced into the draft tube passes through the inserts, a part of the gas is guided along the inner arc surface of each plate body and guided along the shape of the plate body. Leading to one side of the arc surface outside the next insert, thereby producing directional heating away from the outer arc surface; and the inner guide piece and the oblique extension of the outer guide portion , the flow of the gas along the radial direction of the draft tube can be optimized, so that the gas can have a more uniform velocity distribution in the conduction space, thereby reducing the pressure loss and making the temperature distribution more uniform, effectively by the structure The relatively compact inserts optimize heating efficiency and overall heat transfer properties.

Referring to FIG. 3, an embodiment of a radiant tube device of the present invention is suitable for introducing a gas to heat a specific object, and includes a draft tube defining a conductive space 300 extending along a flow direction D of gas conduction. 3, and a plurality of inserts 4 disposed in the conductive space 300 and aligned in the flow direction D.

Referring to FIG. 4 and FIG. 5, each of the inserts 4 includes a curved body 41, two inner guide portions 42 disposed on the plate 41, and two disposed on the plate 41 and located in the inner guide. An outer guide piece portion 43 on the opposite side of the sheet portion 42 , two upstream overlapping portions 44 extending integrally with the plate body 41 , and two extending integrally with the plate body 41 and located opposite to the upstream overlapping portions 44 respectively Downstream lap 45.

The plate body 41 has an inner curved surface 411, an outer curved surface 412 opposite to the inner curved surface 411, an upstream end edge 413, and a downstream end edge 414 at an opposite end of the upstream end edge 413. A connecting edge 415 at the opposite ends of the upstream end 413 and the downstream end 414. The upstream laps 44 extend outwardly from the engaging edges 415 and are spaced apart from the upstream end 413, and the downstream laps 45 extend from the engaging edges 415, respectively, and are located upstream of the connecting edges 415 The lap portion 44 is opposite to the rear and is coupled to the downstream end edge 414. The radius of curvature r1 of the upstream end 413 is greater than the radius of curvature r2 of the downstream end 414, and the upstream laps 44 of each of the inserts 4 and the downstream laps 45 are along the board. The body 41 is curved and continuously extended, and the upstream lap 44 and the downstream lap 45 on the same side are spaced apart from each other to define a groove 490.

Referring to FIG. 6 to FIG. 8 , the inner guide piece portions 42 extend obliquely from the inner curved surface 411 of the plate body 41 toward each other, and extend obliquely in the flow direction D away from each other, the inner guide pieces The front end spacing of the portion 42 defines an inner front opening 428 and the rear end spacing defines an inner rear opening 429 that is smaller than the inner rear opening 429. Each of the inner guide portions 42 has an inner front end 421 facing the flow direction D and an inner rear end 422 opposite to the inner front end 421. The inner front end 421 is away from the inner curved surface 411. Greater than the length of the inner rear end edge 422 away from the inner arc surface 411. The outer guide piece portions 43 extend obliquely away from each other from the outer curved surface 412 of the plate body 41, and extend obliquely in the flow direction D away from each other, and the front end intervals of the outer guide piece portions 43 define an outer portion. The front port 438 defines an outer rear port 439 that is smaller than the outer port 439. Each of the outer guide pieces 43 has an outer front end 431 facing the flow direction D, and an outer rear end 432 opposite to the outer front end 431, the outer front end 431 being away from the outer curved surface 412. Greater than the length of the outer rear end edge 432 away from the outer curved surface 412. It should be particularly noted that the inner guide portions 42 of each of the inserts 4 are substantially integrally extended with the outer guide portions 43, respectively, to facilitate one side of the inner curved surfaces 411, and the like. The one side of the outer curved surface 412 produces a continuous guiding effect, which also simplifies the process of manufacturing each of the inserts 4.

Referring to FIG. 7 and FIG. 8, each of the engaging edges 415 of the plate body 41 of the insert member 4 has a supporting portion 419 between the upstream overlapping portion 44 and the upstream end edge 413 of the same side, each of which is inserted. The upstream laps 44 of the member 4 can respectively abut the downstream laps 45 of the other insert 4 and support the support segments 419 to the inner arc of the plate 41 of the other insert 4 Face 411, whereby the inserts 4 are connected in series along the flow direction D.

Referring to Figures 9 and 10, the draft tube 3 is defined as having an upstream side 31 adjacent the upstream end 413 of the insert 4 and a downstream side 32 opposite the upstream side 31. When the inserts 4 are connected in series with each other and placed into the draft tube 3, and the gas is introduced from the upstream side 31 of the draft tube 3, the gas will be inserted along the flow direction D toward the same The upstream end 413 of the piece 4 flows. First, when the gas flows to the first insert 4, a portion flows along the inner curved surface 411 of the insert 4, and a portion flows to the space between the outer curved surface 412 and the draft tube 3. in. The gas flowing along the inner arc surface 411 of the insert 4 will follow the guiding of the inner guide portions 42 to allow a portion of the gas to circulate toward the grooves 490 toward the opposite sides. Flowing, and the gas passing through the inner front port 428, due to the difference in curvature between the upstream end 413 and the downstream end 414 of the plate 41, will flow along the inclined plate 41 to the next insert. The space between the outer curved surface 412 of the plate body 41 and the draft tube 3. The gas flowing between the outer arc surface 412 and the draft tube 3 will follow the guides of the outer guide piece portion 43 and the plate body 41, and flow back from the grooves 490 to the plates. The body 41 is adjacent to one side of the inner arc surface 411, and then follows the inner arc surface 411 and the guides of the inner guide portions 42 to the plates 41 to approach the outer curved surfaces 412. One side. When the gas is sequentially guided through a plurality of the inserts 4, the gas is caused to flow toward the side of the arc surface 412 outside the insert 4 as shown in FIG. The space between the face 412 and the draft tube 3 has a higher temperature due to the concentration of thermal energy, so that this embodiment can produce radiant heat along a heating direction H from the outer curved surface 412. Achieve the effect of radiant heating towards a particular direction.

Referring to FIG. 12, a velocity profile for actual simulation of the flow field simulation software is shown. The result shows that after the gas is guided by the inserts 4 in the draft tube 3, the velocity distribution is evenly averaged, and rarely A sudden increase or decrease in speed in a short distance. FIG. 13 is a pressure distribution diagram actually simulated by the flow field simulation software, and the advantage of the speed generated by the guidance of the inserts 4 is more apparently exhibited in the pressure distribution. Due to the smooth relationship, the pressure distribution in the conduction space 300 also presents a relatively smooth state, so that the pressure loss caused by the gas is relatively reduced, and the overall heat transfer property is optimized, so that the gas is easier to be uniform. The flow, while flowing, increases the temperature of the various regions of the conductive space 300 while flowing.

Referring to Figure 14 and in conjunction with Figure 11, Figure 14 shows the heat flux distribution for the actual measurement of the heat flux in the conductive space 300. As a result, it can be seen that the reduction is achieved by the guidance of the inserts 4. In the case where the gas is uniformly displaced and the gas is uniformly flowed, the excellent overall heat transfer property of the present embodiment is reflected in the uniform distribution of the heat flux from the upstream side 31 to the downstream side 32. Therefore, in the present embodiment, through the guidance of the inserts 4, the effect of temperature and heat flux simulation results can surely achieve the average transfer of the thermal energy of the gas from the upstream side 31 to the downstream side 32. The purpose of directional heating is achieved by the fact that the thermal energy is relatively concentrated on one side of the curved surface 412 outside the plate body 41.

In summary, the radiant tube device of the present invention can uniformly reduce the pressure loss and optimize the overall heat transfer by transmitting the inserts 4 arranged in series in the conductive space 300. The effect of the nature is such that the heat flux of the radiant tube device of the present invention exhibits a relatively average state from upstream to downstream, and directional heating is achieved by concentrating the thermal energy toward a specific region, so that it can be achieved. The object of the invention.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the equivalent equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still The scope of the invention is covered.

3‧‧‧drain tube
300‧‧‧Transmission space
31‧‧‧ upstream side
32‧‧‧ downstream side
4‧‧‧ Inserts
41‧‧‧ board
411‧‧‧Inside curved surface
412‧‧‧Outer curved surface
413‧‧‧ upstream end
414‧‧‧ downstream end
415‧‧‧Connected edge
419‧‧‧Support section
42‧‧‧Internal Guides
421‧‧‧ inside front end
422‧‧‧ inside rear end
428‧‧‧ Inside front port
429‧‧‧ Inside and after the mouth
43‧‧‧External Guides
431‧‧‧Outside front side
432‧‧‧Outside rear edge
438‧‧‧External mouth
439‧‧‧ outside port
44‧‧‧Upstream lap
45‧‧‧Down lap joint
490‧‧‧ Groove
R1‧‧‧ radius of curvature
R2‧‧‧ radius of curvature
D‧‧‧Flow direction
H‧‧‧heating direction

Other features and advantages of the present invention will be apparent from the embodiments of the present invention, wherein: Figure 1 is a perspective view showing a conventional radiant tube; Fig. 2 is a schematic view showing another conventional radiant tube Figure 3 is an exploded perspective view showing an embodiment of the radiant tube device of the present invention; Figure 4 is a perspective view showing an insert of the embodiment; Figure 5 is a front view showing the insert at another angle Figure 6 is a cross-sectional view showing one of the inner guide portions of the insert, and one of the outer guide portions; Figure 7 and Figure 8 are schematic views, respectively, with two opposite angles of representation, FIG. 9 is a schematic view showing a plurality of the inserts disposed in a guide tube of the embodiment; FIG. 10 is a schematic view, and FIG. 9 is a side view angle FIG. 11 is a temperature distribution diagram illustrating the temperature distribution that can be formed in this embodiment, thereby showing the heating condition of the embodiment; FIG. 12 is a velocity profile, gas FIG. 13 is a pressure distribution diagram, which is combined with the velocity distribution shown in FIG. 12 to illustrate the effect of reducing the pressure loss achieved by the embodiment; and FIG. 14 is a The heat flux distribution map, together with Figure 13, illustrates the uniform heat transfer that can be formed in this embodiment.

Claims (6)

A radiant tube device comprising: a draft tube defining a conductive space extending in a flow direction of gas conduction; and a plurality of inserts disposed in the conductive space and arranged in the flow direction, each of An insert member includes a plate body having a curved arc shape and having an inner arc surface, an outer arc surface opposite to the inner arc surface, an upstream end edge, and a downstream end edge opposite to the upstream end edge. And a connecting edge respectively connected to the opposite ends of the upstream end side and the downstream end side, wherein a radius of curvature of the upstream end side is greater than a radius of curvature of the downstream end side; and an inner guiding piece portion from the plate body The inner arc faces extend obliquely toward each other and extend obliquely in a direction away from each other along the flow direction, the front end portions of the inner guide portions define an inner front opening, and the rear end interval defines an inner rear opening, The inner front opening is smaller than the inner rear opening; and the two outer guiding portions extend away from each other from the arc surface outside the plate body, and extend obliquely in the direction of the flow away from each other, the outer guiding piece Front end interval Before a fix outer port, and a rear end defining spaced outer port, the port is less than the outer front of the outer rear port. The radiant tube device of claim 1, wherein each of the inserts further comprises two upstream laps extending outward from the engaging edges of the plate and spaced apart from the upstream end, and two separate portions Extending from the connecting edges of the plate body and located opposite the upstream overlapping portions and engaging the downstream overlapping portions of the downstream end sides, each of the engaging edges having an upstream overlapping portion on the same side The support sections between the upstream end edges, the upstream laps of each insert can respectively abut the downstream laps of the other insert and support the support sections to the other insert The inner curved surface of the plate body, whereby the inserts are serially connected in the flow direction. The radiant tube device of claim 2, wherein the upstream laps and the downstream laps of each of the inserts extend continuously along the curved shape of the plate body, and are on the same side. The upstream lap and the downstream lap are spaced apart from each other to define a groove. The radiant tube device of claim 1, wherein the inner guide portions of each of the inserts extend substantially integrally with the outer guide portions. The radiant tube device of claim 1, wherein each of the inner guide portions of each of the inserts has an inner front end side facing the flow direction, and an inner rear end side opposite to the inner front end side, The length of the inner front end away from the inner curved surface is greater than the length of the inner rear end away from the inner curved surface. The radiant tube device of claim 1, wherein each of the outer guide portions of each of the inserts has an outer front end facing the flow direction and an outer rear end opposite the outer front end, The length of the outer front end away from the outer curved surface is greater than the length of the outer rear end away from the outer curved surface.