Blind tube type gas radiant tube with long service life

Abstract

The utility model discloses a blind tube type gas radiant tube with long service life, and belongs to the field of radiant tubes. The combustion-supporting air distribution holes communicated with the waste gas collection chamber are formed in the side wall of the end, close to the outlet, of the combustion-supporting air inlet pipe in the circumferential direction in a surrounding mode, so that part of air of the combustion-supporting air inlet pipe can enter the waste gas collection chamber through the combustion-supporting air distribution holes before combustion; waste gas containing residual fuel gas after primary combustion and combustion-supporting air entering the waste gas collecting cavity in advance can be subjected to secondary combustion, and by means of the two-time combustion mode, uniformity of temperature distribution in the radiant tube can be greatly promoted, so that deformation of a tube body due to the heat effect is reduced, and the service life of the radiant tube is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of radiant tubes, and more specifically to a long-life blind tube type gas radiant tube. Background Art

[0002] Gas-fired radiant tubes are often used for heat treatment of metal materials. Gas burns in the radiant tubes and radiates heat through the tube wall, indirectly heating the material parts to be treated. At present, there are many types of gas-fired radiant tubes used in industrial sites, such as U-type, P-type, W-type, I-type, etc., all of which use heat exchange burners. The most common form of burners is the long flame type. One disadvantage of this burner during use is that the temperature difference of the radiant tube in the length direction of the tube body is relatively large. The radiant tube in the front section of the flame is sprayed by the flame and has a high temperature, while the radiant tube in the rear section of the flame is sprayed by the flame and has a low temperature. This causes uneven heating of the radiant tube, and the tube body is deformed or even cracked due to the thermal effect, which affects the service life of the radiant tube.

[0003] The patent with publication number CN202177101 U discloses a self-preheating radiant tube gas burner, in which the outer coaxial sleeve of the burner body is provided with an air duct, the outer coaxial sleeve of the air duct is provided with a heat exchange tube, and the burner mounting seat is also provided with an exhaust gas outlet, radial gaps are left between the air duct, the heat exchange tube and the exhaust hole, the other end of the air duct is contracted into a flame nozzle, a primary air inlet hole is provided on the tube wall in the middle section of the air duct, the other end of the heat exchange tube is contracted into a secondary air nozzle, and a flame tube is placed in the radiant tube, and high-temperature exhaust gas is used to preheat the combustion air to increase the theoretical combustion temperature, and at the same time, part of the exhaust gas is sucked in to participate in the combustion, so as to realize high-temperature air oxygen-poor combustion and make the flame temperature more uniform. The above design provides new ideas for burner design, and there is still room for further optimization in practical applications. Utility Model Content

[0004] 1. Technical problems to be solved by the utility model

[0005] The purpose of the utility model is to overcome the problem in the prior art that uneven heating of radiant tubes affects the service life, and to provide a long-life blind tube type gas radiant tube, which can greatly improve the uniformity of temperature distribution in the radiant tube, thereby reducing deformation of the tube body due to thermal effects and extending the service life of the radiant tube.

[0006] 2. Technical solution

[0007] In order to achieve the above-mentioned purpose, the technical solution provided by the utility model is:

[0008] The utility model discloses a long-life blind-tube gas radiant tube, comprising a radiant tube outer tube body, a gas inlet pipe is coaxially arranged inside the radiant tube outer tube body, a combustion-supporting air inlet pipe is coaxially arranged outside the gas inlet pipe, a passage between the combustion-supporting air inlet pipe and the gas inlet pipe is a combustion-supporting air collecting chamber, a passage between the combustion-supporting air inlet pipe and the radiant tube outer tube body is an exhaust gas collecting chamber, and an exhaust gas exhaust pipe is arranged on one side of the exhaust gas collecting chamber;

[0009] Combustion air distribution holes connected to the exhaust gas collecting chamber are circumferentially arranged on the side wall of the combustion air inlet pipe near the outlet end, so that the air in the combustion air inlet pipe can enter the exhaust gas collecting chamber through the combustion air distribution holes before combustion.

[0010] Furthermore, a heat exchanger is circumferentially arranged on the side wall of the combustion air intake pipe near the inlet end, and the heat exchanger does not extend to the area where the combustion air distribution holes are located along the axial direction of the combustion air intake pipe.

[0011] Furthermore, a partition inner cylinder is coaxially provided inside the combustion air intake pipe near the outlet end, and the partition inner cylinder surrounds the outer periphery of the fuel gas intake pipe; the axial extension length of the partition inner cylinder is not less than the axial distribution length of the combustion air distribution holes, and the outlet end of the partition inner cylinder extends to a position beyond the front of the combustion air distribution holes, and a closed partition is connected to the inner wall of the combustion air intake pipe, so that an air diversion channel is formed between the partition inner cylinder and the combustion air distribution holes.

[0012] Furthermore, a circle of inclined baffles that are inclined and expanded outward are provided along the circumferential direction at the inlet end of the separating inner cylinder, and the inner diameter of the opening at the tail end of the inclined baffle is larger than the inner diameter of the separating inner cylinder. The tail end of the inclined baffle extends close to the inner wall of the combustion air inlet pipe, and the inclined baffle is provided with air distribution holes that penetrate the thickness direction, which are used for combustion air to enter the air diversion channel between the separating inner cylinder and the combustion air distribution holes, and finally enter the exhaust gas collecting chamber through the combustion air distribution holes.

[0013] Furthermore, along the axial direction of the combustion air intake pipe, a diameter reduction section is provided in the middle area of ​​the combustion air intake pipe, and the inner diameter of the diameter reduction section is smaller than the inner diameter of other areas of the combustion air intake pipe located in front and behind it.

[0014] Furthermore, both ends of the reduced diameter section of the combustion-supporting air intake pipe are transitionally connected to the front and rear combustion-supporting air intake pipes respectively through inclined plates.

[0015] Furthermore, along the gas intake flow direction, the heat exchanger is arranged in the rear area of ​​the reduced diameter section of the combustion air intake pipe, and the combustion air distribution holes are arranged in the front area of ​​the reduced diameter section of the combustion air intake pipe.

[0016] Furthermore, a reduced diameter section is provided in the middle area of ​​the combustion air intake pipe, and the inner diameter of the reduced diameter section is smaller than the inner diameter of other areas of the combustion air intake pipe located in front and behind it. Along the axial direction of the combustion air intake pipe, the separating inner cylinder is located in the front area of ​​the reduced diameter section of the combustion air intake pipe, and has an axial gap with the front end of the reduced diameter section, and the tail end of the inclined baffle extends to the front expansion area of ​​the reduced diameter section.

[0017] Furthermore, the inner diameter of the partition inner cylinder is substantially consistent with the inner diameter of the reduced diameter section of the combustion air intake pipe.

[0018] Furthermore, the heat exchanger adopts a heat exchange fin structure, and multiple groups of heat exchange fins surround the outer periphery of the combustion air intake pipe, and one end extends into the inner cavity of the combustion air intake pipe, and the other end extends into the exhaust gas collecting chamber.

[0019] 3. Beneficial effects

[0020] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects:

[0021] (1) The gas radiant tube of the utility model is provided with combustion air distribution holes connected with the exhaust gas collecting chamber on the side wall of the combustion air inlet pipe near the outlet end in a circumferential direction, so that part of the air in the combustion air inlet pipe can enter the exhaust gas collecting chamber through the combustion air distribution holes before combustion. After the remaining combustion air is mixed with the fuel gas at the front end for one combustion, the fuel gas remains in the exhaust gas after combustion due to the reduction in the amount of the combustion air. The exhaust gas containing the residual fuel gas can be subjected to a second combustion with the combustion air that has entered the exhaust gas collecting chamber in advance. Through such a two-combustion method, the uniform temperature distribution in the radiant tube can be greatly promoted, thereby reducing the deformation of the tube body due to the thermal effect and extending the service life of the radiant tube.

[0022] (2) In the gas radiant tube of the utility model, a heat exchanger is provided circumferentially along the side wall of the combustion air intake pipe near the inlet end. The rear section of the combustion air intake pipe is isolated from the exhaust gas collecting chamber after combustion by the heat exchanger. The combustion air that subsequently enters can be preheated by the heat exchanger, which promotes subsequent combustion, improves the overall thermal efficiency of the radiant tube, and saves energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of the gas radiant tube in the embodiment.

[0024] Explanation of the symbols in the schematic diagram:

[0025] 1. Gas inlet pipe; 2. Combustion-supporting air inlet pipe; 3. Waste gas exhaust pipe; 4. Combustion-supporting air distribution holes; 5. Waste gas collecting chamber; 6. Combustion-supporting air collecting chamber; 7. Heat exchanger; 8. Radiant tube outer tube body; 9. Inclined baffle; 10. Partition inner tube; 11. Closed partition. DETAILED DESCRIPTION

[0026] In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] The utility model is further described below in conjunction with embodiments.

[0029] Example

[0030] Combination Figure 1 As shown, a long-life blind tube type gas radiant tube of the present embodiment comprises a radiant tube outer tube body 8, a gas inlet pipe 1 is coaxially arranged inside the radiant tube outer tube body 8, a combustion air inlet pipe 2 is coaxially arranged on the outer periphery of the gas inlet pipe 1, a passage between the combustion air inlet pipe 2 and the gas inlet pipe 1 is a combustion air collecting chamber 6, a passage between the combustion air inlet pipe 2 and the radiant tube outer tube body 8 is an exhaust gas collecting chamber 5, an exhaust gas exhaust pipe 3 is arranged on one side of the exhaust gas collecting chamber 5; in practice, the gas inlet pipe 1 can adopt a straight-through intake, and the intake port is directly arranged at the end in the axial direction, and the combustion air inlet pipe 2 can adopt a side intake, that is, an intake port is arranged on the side for the combustion air to enter, such as Figure 1 as shown in .

[0031] In terms of gas flow direction, combined Figure 1In the middle position, the left side in this embodiment is the rear side, which is the inlet end of each pipeline, and the right side is the front side, which is the outlet end of each pipeline. In this embodiment, combustion air distribution holes 4 connected to the exhaust gas collecting chamber 5 are circumferentially arranged on the side wall of the combustion air intake pipe 2 near the outlet end, so that the air in the combustion air intake pipe 2 can enter the exhaust gas collecting chamber 5 through the combustion air distribution holes 4 before combustion. The combustion air distribution holes 4 are distributed along the axial extension of the combustion air intake pipe 2 for a certain length. By setting the combustion air distribution holes 4, a part of the combustion air can enter the exhaust gas collecting chamber 5 first, and the remaining combustion air is mixed with the fuel gas at the front end for a primary combustion. Due to the reduction in the amount of combustion air, there is residual fuel gas in the exhaust gas after combustion. When these exhaust gases containing residual fuel gas are exhausted through the exhaust gas exhaust pipe 3, they can be secondary burned with the combustion air that has entered the exhaust gas collecting chamber 5 in advance. Through this double combustion method, the uniform temperature distribution in the radiation tube can be greatly promoted, thereby reducing the deformation of the tube body due to thermal effects and extending the service life of the radiation tube.

[0032] Preferably, in order to improve the overall thermal efficiency of the radiant tube at the same time, further, a heat exchanger 7 is provided on the side wall of the combustion air intake pipe 2 near the inlet end, i.e., on the left end side wall, in the circumferential direction, and the heat exchanger 7 does not extend to the area where the combustion air distribution holes 4 are located along the axial direction of the combustion air intake pipe 2. In practice, the heat exchanger 7 can be selected to adopt a heat exchange fin structure, with multiple groups of heat exchange fins surrounding the outer periphery of the combustion air intake pipe 2, and one end extending into the inner cavity of the combustion air intake pipe 2, and the other end extending into the exhaust gas collecting chamber 5. The rear section of the combustion air intake pipe 2 is isolated from the exhaust gas collecting chamber 5 after combustion by the heat exchanger 7, and the combustion air entering later can be preheated by the heat exchanger 7 to promote subsequent combustion, improve the overall thermal efficiency of the radiant tube, and save energy.

[0033] In order to more accurately control the distribution of combustion-supporting air, a partition inner cylinder 10 is coaxially arranged inside the combustion-supporting air inlet pipe 2 near the outlet end, and the partition inner cylinder 10 surrounds the outer periphery of the gas inlet pipe 1; the axial extension length of the partition inner cylinder 10 is not less than the axial distribution length of the combustion-supporting air distribution hole 4, and the outlet end of the partition inner cylinder 10 extends to a position beyond the front of the combustion-supporting air distribution hole 4, and a closed partition plate 11 is connected to the inner wall of the combustion-supporting air inlet pipe 2, so that an air diversion channel is formed between the partition inner cylinder 10 and the combustion-supporting air distribution hole 4. An outlet for the combustion of gas and combustion-supporting air is also arranged at the center of the outlet end of the partition inner cylinder 10, and the outlet end of the partition inner cylinder 10 has a tapered section with a gradually decreasing inner diameter along the axial direction forward, and the tapered section extends beyond the front of the combustion-supporting air distribution hole 4, and the outlet is arranged at the center of the tapered section, which can improve the flow rate and pressure of the combustion-supporting air and promote full combustion. The partition inner cylinder 10 is arranged to form an air diversion channel between the partition inner cylinder 10 and the combustion air distribution holes 4. The combustion air first enters the air diversion channel through the gap between the left end of the partition inner cylinder 10 and the inner wall of the combustion air inlet pipe 2, and then enters the exhaust gas collecting chamber 5 through the combustion air distribution holes 4, thereby limiting only an appropriate amount of combustion air to enter the exhaust gas collecting chamber 5 in advance, and avoiding affecting the first full combustion of the combustion air and fuel gas.

[0034] A more preferred design is that the inlet end of the partition inner cylinder 10 is provided with a circle of inclined baffles 9 that expand outward along the circumferential direction, the inner diameter of the opening of the left tail end of the inclined baffle 9 is larger than the inner diameter of the partition inner cylinder 10, the tail end of the inclined baffle 9 extends close to the inner wall of the combustion air inlet pipe 2, and the inclined baffle 9 is provided with air distribution holes that penetrate the thickness direction, for the combustion air to enter the air diversion channel between the partition inner cylinder 10 and the combustion air distribution holes 4, and finally enter the exhaust gas collecting chamber 5 through the combustion air distribution holes 4. The design of the inclined baffle 9 further limits the entrance of the air diversion channel to avoid the pre-discharge of excessive combustion air. In practice, it is appropriate for about 30% of the combustion air to enter the exhaust gas collecting chamber 5 through the combustion air distribution holes 4.

[0035] In order to optimize the flow rate and pressure of the combustion-supporting air, a diameter-reducing section is provided in the middle area of ​​the combustion-supporting air intake pipe 2 along the axial direction thereof, and the inner diameter of the diameter-reducing section is smaller than the inner diameter of other areas of the combustion-supporting air intake pipe 2 located in front and behind thereof. Preferably, both ends of the diameter-reducing section of the combustion-supporting air intake pipe 2 are transitionally connected to the combustion-supporting air intake pipe 2 in front and behind thereof respectively through inclined plates. Figure 1As shown, the reduced diameter section is the middle area with a smaller inner diameter, and the left rear end and the right front end of the combustion air intake pipe 2 are both areas with a larger inner diameter. Correspondingly, the heat exchanger 7 is arranged in the rear area of ​​the reduced diameter section of the combustion air intake pipe 2, and the combustion air distribution hole 4 is arranged in the front area of ​​the reduced diameter section of the combustion air intake pipe 2. Correspondingly, the partition inner cylinder 10 is located in the right front area of ​​the reduced diameter section of the combustion air intake pipe 2, and the inner diameter of the partition inner cylinder 10 is basically consistent with the inner diameter of the reduced diameter section of the combustion air intake pipe 2, and there is an axial gap with the front end of the reduced diameter section, and the tail end of the inclined baffle 9 extends to the front expansion area of ​​the reduced diameter section. In this way, the combustion air accelerated by the reduced diameter section can continue to spray forward and burn at a substantially equivalent speed, and when entering the front expansion area of ​​the reduced diameter section, part of the combustion air quickly enters the air diversion channel through the inclined baffle 9, and finally enters the exhaust gas collecting chamber 5 through the combustion air distribution hole 4.

[0036] The above is a schematic description of the present invention and its implementation methods, which is not restrictive and is only one of the implementation methods of the present invention, and is not actually limited to this. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A long-life blind-tube gas radiant tube, characterized in that: The invention comprises a radiation tube outer tube body (8), a gas inlet pipe (1) is coaxially arranged inside the radiation tube outer tube body (8), a combustion air inlet pipe (2) is coaxially arranged outside the gas inlet pipe (1), a passage between the combustion air inlet pipe (2) and the gas inlet pipe (1) is a combustion air collecting chamber (6), a passage between the combustion air inlet pipe (2) and the radiation tube outer tube body (8) is an exhaust gas collecting chamber (5), and an exhaust gas exhaust pipe (3) is arranged on one side of the exhaust gas collecting chamber (5); Combustion air distribution holes (4) connected to the exhaust gas collecting chamber (5) are circumferentially arranged on the side wall of the combustion air intake pipe (2) near the outlet end, so that the air in the combustion air intake pipe (2) can enter the exhaust gas collecting chamber (5) through the combustion air distribution holes (4) before combustion.

2. A long-life blind-tube gas radiant tube according to claim 1, characterized in that: A heat exchanger (7) is circumferentially arranged on the side wall of the combustion air intake pipe (2) near the inlet end, and along the axial direction of the combustion air intake pipe (2), the heat exchanger (7) does not extend to the area where the combustion air distribution holes (4) are located.

3. A long-life blind-tube gas radiant tube according to claim 1, characterized in that: A partition inner cylinder (10) is coaxially arranged inside the combustion air inlet pipe (2) near one end of the outlet, and the partition inner cylinder (10) surrounds the outer periphery of the fuel gas inlet pipe (1); the axial extension length of the partition inner cylinder (10) is not less than the axial distribution length of the combustion air distribution holes (4), and the outlet end of the partition inner cylinder (10) extends to a position beyond the front of the combustion air distribution holes (4), and a closed partition plate (11) is connected to the inner wall of the combustion air inlet pipe (2), so that an air diversion channel is formed between the partition inner cylinder (10) and the combustion air distribution holes (4).

4. A long-life blind-tube gas radiant tube according to claim 3, characterized in that: The inlet end of the partition inner tube (10) is provided with a circle of inclined baffles (9) that are inclined and expanded outward along the circumferential direction. The inner diameter of the opening at the rear end of the inclined baffle (9) is larger than the inner diameter of the partition inner tube (10). The rear end of the inclined baffle (9) extends close to the inner wall of the combustion air inlet pipe (2), and the inclined baffle (9) is provided with air distribution holes that penetrate the thickness direction, so as to allow the combustion air to enter the air diversion channel between the partition inner tube (10) and the combustion air distribution holes (4), and finally enter the exhaust gas collecting chamber (5) through the combustion air distribution holes (4).

5. A long-life blind-tube gas radiant tube according to claim 2, characterized in that: Along the axial direction of the combustion air intake pipe (2), a diameter-reducing section is provided in the middle area of ​​the combustion air intake pipe (2), and the inner diameter of the diameter-reducing section is smaller than the inner diameter of other areas of the combustion air intake pipe (2) located in front and behind the diameter-reducing section.

6. A long-life blind-tube gas radiant tube according to claim 5, characterized in that: Both ends of the reduced diameter section of the combustion-supporting air intake pipe (2) are transitionally connected to the front and rear combustion-supporting air intake pipes (2) respectively through inclined plates.

7. A long-life blind-tube gas radiant tube according to claim 5, characterized in that: Along the gas intake flow direction, the heat exchanger (7) is arranged in the rear area of ​​the reduced diameter section of the combustion air intake pipe (2), and the combustion air distribution holes (4) are arranged in the front area of ​​the reduced diameter section of the combustion air intake pipe (2).

8. The long-life blind-tube gas radiant tube according to claim 4, characterized in that: A reduced diameter section is provided in the middle area of ​​the combustion-supporting air intake pipe (2), the inner diameter of which is smaller than the inner diameter of other areas of the combustion-supporting air intake pipe (2) located in front and behind it. Along the axial direction of the combustion-supporting air intake pipe (2), the partition inner tube (10) is located in the front area of ​​the reduced diameter section of the combustion-supporting air intake pipe (2) and has an axial gap with the front end of the reduced diameter section. The rear end of the inclined baffle (9) extends to the front expansion area of ​​the reduced diameter section.

9. A long-life blind-tube gas radiant tube according to claim 8, characterized in that: The inner diameter of the partition inner cylinder (10) is substantially consistent with the inner diameter of the reduced diameter section of the combustion-supporting air intake pipe (2).

10. A long-life blind-tube gas radiant tube according to claim 2, characterized in that: The heat exchanger (7) adopts a heat exchange fin structure, wherein a plurality of groups of heat exchange fins surround the outer periphery of the combustion air intake pipe (2), and one end extends into the inner cavity of the combustion air intake pipe (2), and the other end extends into the exhaust gas collecting chamber (5).

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