Radiant inner tube and radiant tube

Abstract

Embodiments of the present application provide a radiation inner tube and a radiation tube, wherein the radiation inner tube comprises an inner tube body, the inner tube body comprises an air inlet end and an air outlet end, a small hole tube is arranged outside the inner tube body and communicates with the inside of the inner tube body, the included angle between the axis of the small hole tube and the axis of the inner tube body is 10-20 degrees, and the small hole tube is arranged obliquely towards the air inlet end; the inner tube body and the small hole tube are both made of heat-resistant metal material. The radiation inner tube of the present application is an integrated heat-resistant metal structure, a deformation prevention rib plate is arranged outside the radiation inner tube, which is beneficial to avoid the problem that the equipment is prone to breakage during installation, transportation and use; the radiation inner tube in the present application comprises a small hole tube, the small hole tube does not affect the normal circulating combustion in the radiation tube when the radiation inner tube is in normal operation, and when the radiation tube is deformed, the gas outside the inner tube body can enter the inside of the inner tube through the small hole tube, so that the circulating combustion is realized.

Description

Technical Field

[0001] This invention relates to the field of radiant tubes, and more specifically, to a radiant inner tube and a radiant tube. Background Technology

[0002] The existing radiant tube and inner tube structure are roughly as follows: Figure 1 As shown, both the radiant tube and the inner tube are made of SiC. After prolonged use, the radiant tubes of existing heat treatment furnaces are easily deformed by changes in furnace temperature. This deformation causes damage to the inner tube, as SiC is extremely prone to damage. When the radiant tube is deformed or damaged, the inner tube will also be damaged or broken. Deformation of the radiant tube also makes it difficult or impossible to install the SiC inner tube. This can prevent the flame ejected from the burner of the heat treatment furnace from forming a circulating combustion inside the radiant tube, leading to a series of malfunctions such as the burner failure. This greatly complicates the maintenance of the heat treatment furnace and increases the maintenance cost of the heat treatment equipment. Summary of the Invention

[0003] The present invention aims to provide, for example, a radiant inner tube and a radiant tube, which uses a heat-resistant metal instead of silicon carbide to avoid the problem that the radiant inner tube is easily broken after being squeezed, thus affecting the normal operation of the radiant tube.

[0004] The embodiments of the present invention can be implemented as follows:

[0005] In a first aspect, the present invention provides a radiating inner tube, comprising an inner tube body, the inner tube body including an air inlet end and an air outlet end, a small hole tube communicating with the interior of the inner tube body is provided on the outer side of the inner tube body, the angle between the axis of the small hole tube and the axis of the inner tube body is 10°-20°, and the small hole tube is inclined toward the air inlet end; both the inner tube body and the small hole tube are made of heat-resistant metal.

[0006] In an optional embodiment, the inner tube body is provided with ribs along the axial direction of the inner tube body, and there are two or more ribs arranged sequentially along the circumference of the inner tube body.

[0007] In an optional embodiment, the perforated tubes are arranged in two or more rows along the circumference of the inner tube body, and each row of the perforated tubes includes two or more perforated tubes arranged along the axial direction of the inner tube body.

[0008] In an optional embodiment, the perforated tube is uniformly welded onto the inner tube body.

[0009] In an optional embodiment, the angle between the axis of the small-hole tube and the axis of the inner tube body is 15°.

[0010] In an optional embodiment, the heat-resistant metal is Cr25Ni35Nb heat-resistant cast steel.

[0011] Secondly, the present invention provides a radiant tube, comprising a radiant tube body made of heat-resistant metal, one end of the radiant tube body being closed and the other end being provided with a burner, the burner being provided with a gas inlet, an air inlet and a flue gas outlet, wherein the radiant inner tube of any of the foregoing embodiments is disposed within the radiant tube body, the air inlet end of the inner tube body being close to the burner and having a gap between them, the air outlet end of the inner tube body being close to the closed end of the radiant tube body and having a gap between them, a flue gas passage being provided between the inner tube body and the radiant tube body, the air inlet end of the flue gas passage being connected to the air outlet end of the inner tube body, and the air outlet end of the flue gas passage being connected to the burner.

[0012] In an optional embodiment, the end of the small-hole tube away from the inner tube body abuts against the inner wall of the radiating tube body.

[0013] In an optional embodiment, the burner includes an inner tube, an outer tube, and an exhaust channel disposed between the inner tube and the outer tube. A baffle ring is provided at one end of the inner tube near the inner tube body, and an air inlet is provided in the middle of the baffle ring. The interior of the radiant tube body is connected to the flue gas outlet through the exhaust channel.

[0014] In an optional embodiment, the retaining ring gradually tilts towards the direction of the radiating inner tube along a direction close to the axis of the inner tube.

[0015] The beneficial effects of the embodiments of the present invention include, for example:

[0016] The radiant inner tube of this application is an integral heat-resistant metal structure. Anti-deformation ribs are provided on the outside of the radiant inner tube, which helps to avoid the problem of easy breakage during equipment installation, transportation and use. Even if the radiant tube is deformed and the radiant inner tube is under pressure, it can still be used.

[0017] The radiant inner tube in this application includes a small-hole tube, and the end of the small-hole tube is inclined towards the outlet end of the inner tube body. When the radiant inner tube is working normally, the small-hole tube will not affect the normal circulating combustion inside the radiant tube. However, when the radiant tube is deformed, it may cause the distance between the local radiant tube and the radiant inner tube to decrease or even become blocked. In this case, the gas outside the inner tube body can enter the inner side of the inner tube through the small-hole tube to achieve circulating combustion. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the burner and radiant inner tube of an existing heat treatment furnace;

[0020] Figure 2 This is a schematic diagram of the structure of the radiating inner tube in this application;

[0021] Figure 3 This is a schematic diagram of the structure of the radiator tube in this application.

[0022] Icons: 100-Radiant inner tube; 110-Inner tube body; 120-Small hole tube; 130-Rib plate; 200-Radiant tube; 210-Burn; 211-Inner layer tube; 212-Outer layer tube; 213-Exhaust passage; 214-Baffle ring; 220-Radiant tube body; 230-Flue gas passage. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0027] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0028] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0029] Please refer to Figure 2 This embodiment provides an inner tube for a radiant tube 200, including an inner tube body 110. The inner tube body 110 includes an air inlet end and an air outlet end. A small perforated tube 120 communicating with the interior of the inner tube body 110 is provided on the outer side of the inner tube body 110. The angle between the axis of the small perforated tube 120 and the axis of the inner tube body 110 is 10°-20°, and the small perforated tube 120 is inclined toward the air inlet end. Both the inner tube body 110 and the small perforated tube 120 are made of heat-resistant metal.

[0030] In this embodiment, the inner tube of the radiant tube 200 is made of heat-resistant metal. Metal has a certain degree of deformability and will generally deform rather than break when subjected to external force, which can extend its service life to a certain extent.

[0031] In addition, the radiant inner tube 100 in this embodiment includes a small-hole tube 120, and the end of the small-hole tube 120 is inclined towards the outlet end of the inner tube body 110. When the radiant inner tube 100 is working normally, since the direction of the end of the small-hole tube 120 connected to the inner tube body 110 is opposite to the gas flow direction inside the inner tube body 110, and the direction of the end of the small-hole tube 120 is opposite to the gas flow direction outside the inner tube body 110, the gas outside the radiant inner tube 100 will not enter the inner side of the radiant inner tube 100 through the small-hole tube 120, and will not affect the normal circulating combustion inside the radiant tube 200. To ensure that the orifice tube 120 does not interfere with the normal operation of the inner radiant tube 100, the angle between the axis of the orifice tube 120 and the axis of the inner tube body 110 is set to 10°-20°. Specifically, it can be any value between 10°, 12°, 14°, 16°, 18°, 20°, or 10°-20°. Preferably, the axis of the inner tube body 110 and the axis of the orifice tube 120 are arranged in the same plane. However, when the radiant tube 200 deforms, the distance between the local radiant tube 200 and the inner radiant tube 100 may decrease or even become blocked. In this case, the gas pressure outside the inner tube body 110 will be greater than the gas pressure inside the inner tube body 110, causing the gas outside the inner tube body 110 to enter the inner tube through the orifice tube 120 and achieve circulating combustion. Furthermore, the orifice tube 120 in this embodiment also has a certain degree of deformability. When the orifice tube 120 is subjected to external force, the angle between the orifice tube 120 and the axis of the inner tube 110 will be further reduced, making the angle between the gas direction leaving the end of the orifice tube 120 connected to the inner tube 110 and the gas in the inner tube 110 smaller. This reduces the kinetic energy loss of the gas in the orifice tube 120 entering the inner tube 110, which is beneficial to maintaining the efficiency of the circulating combustion.

[0032] In this embodiment, the small-hole tube 120 and the inner tube body 110 can be connected by welding or other methods. Specifically, a through hole can be provided on the inner tube body 110 first, and then the small-hole tube 120 can be inserted into the through hole and fixed by welding or other methods. Alternatively, a stepped hole can be provided on the inner tube body 110, wherein the diameter of the stepped hole near the inner side of the inner tube body 110 is smaller than the diameter of the stepped hole near the outer side of the inner tube body 110, so that the small-hole tube 120 can be inserted into the stepped hole and then welded to the inner tube body 110. The small end of the stepped hole can also play a certain limiting role.

[0033] In this embodiment, there are no special requirements for the diameter of the small hole tube 120. Specifically, two or three centimeters or seven or eight centimeters are acceptable. It can be selected according to the specifications of the inner tube body 110. Generally, if the diameter of the small hole tube 120 is small, it can be set densely. If the diameter of the small hole tube 120 is large, it can be set sparsely.

[0034] In an optional embodiment, the inner tube 110 is provided with ribs 130 along the axial direction of the inner tube 110, and there are two or more ribs 130 arranged sequentially along the circumference of the inner tube 110.

[0035] The presence of stiffening ribs 130 strengthens the inner tube 110, helping it resist external forces and reducing the possibility of deformation. Specifically, two, three, four, five, six, seven, eight, or more stiffening ribs 130 can be provided. However, excessively dense stiffening ribs 130 may affect heat radiation, while excessively sparse stiffening will not provide significant reinforcement. The cross-section of the stiffening ribs 130 can be square, rectangular, or other shapes. In this embodiment, six stiffening ribs 130 are provided, with an arc distance of π / 3 between adjacent stiffening ribs 130. The cross-section of each stiffening rib 130 is square, and the stiffening ribs 130 and the inner tube 110 can be fixed together by welding.

[0036] It should be noted that although the ribs 130 arranged in a ring on the outside of the inner tube 110 can also strengthen the inner tube 110, they will affect the flow of gas on the outside of the inner tube 110. Therefore, it is preferable that the ribs 130 are arranged along the circumference of the inner tube 110.

[0037] In addition, the stiffener 130 in this embodiment can provide support when the outer tube deforms and compresses the inner tube 110. When the small hole tube 120 is pressed by external force on the stiffener 130, it can provide support for the small hole tube 120, so that the distance between the inner tube 110 and the radial tube 200 located on its outer side is not too small.

[0038] In an optional embodiment, the perforated tube 120 is arranged in two or more rows along the circumference of the inner tube body 110, and each row of the perforated tube 120 includes two or more perforated tubes 120 arranged along the axial direction of the inner tube body 110.

[0039] In this embodiment, the small hole tube 120 can be arranged along the axial direction of the inner tube body 110, and can be arranged from the air inlet end to the air outlet end of the inner tube body 110, or can be interrupted in the middle as needed; adjacent rows of small hole tubes 120 can be arranged opposite each other or staggered, preferably adjacent small hole tubes 120 are staggered.

[0040] In an optional embodiment, the perforated tube 120 is uniformly welded onto the inner tube body 110.

[0041] In an optional embodiment, the angle between the axis of the small-hole tube 120 and the axis of the inner tube body 110 is 15°.

[0042] In an optional embodiment, the heat-resistant metal is Cr25Ni35Nb heat-resistant cast steel.

[0043] Another embodiment of this application provides a radiant tube 200, such as Figure 3 As shown, the radiant tube 220 includes a heat-resistant metal tube body 220. One end of the radiant tube 220 is closed, and the other end is provided with a burner 210. The burner 210 is provided with a gas inlet, an air inlet, and a flue gas outlet. In any of the aforementioned embodiments, the inner tube of the radiant tube 200 is disposed inside the radiant tube 220. The air inlet end of the inner tube 110 is close to the burner 210 and a gap is provided between them. The air outlet end of the inner tube 110 is close to the closed end of the radiant tube 220 and a gap is provided between them. A flue gas passage 230 is provided between the inner tube 110 and the radiant tube 220. The air inlet end of the flue gas passage 230 is connected to the air outlet end of the inner tube 110, and the air outlet end of the flue gas passage 230 is connected to the burner 210.

[0044] Specifically, in this embodiment, when the radiant tube 200 is operating normally, the fuel gas and the oxidizing gas (air) enter the burner 210 through the gas inlet and air inlet, respectively. They mix and ignite to form high-temperature combustion products that continue to burn inside the inner tube 110. After leaving the inner tube 110, the mixed gas flows into the flue gas passage 230 from the closed end of the radiant tube 200. A portion of the flue gas leaving the flue gas passage 230 is drawn into the inner tube 110 for circulation when the mixed gas enters it, while a portion exits through the burner 210 from the flue gas outlet. When the radiant tube 200 or the inner tube 110 is deformed by external force, causing the flue gas passage 230 to narrow or even form a dead zone, the flue gas within the flue gas passage 230 can still smoothly circulate through the perforated tube 120.

[0045] In an optional embodiment, one end of the small-hole tube 120 away from the inner tube body 110 abuts against the inner wall of the radiating tube body 220.

[0046] The small-hole tube 120 is positioned between the inner tube 110 and the radiating tube 220, providing support for the inner tube 110. During manufacturing, the distance from the end of the small-hole tube 120 to the outer surface of the inner tube 110 can be equal to the distance between the inner tube 110 and the radiating tube 220. This allows the inner tube 110 to be easily placed directly inside the radiating tube 220, thus achieving support and positioning for the inner tube 110. Further reinforcement of the inner tube 110 using hanging components or other structures is then necessary, facilitating the assembly of the inner tube 110 and the radiating tube 200.

[0047] It should be noted that, since the outlet end face of the small hole tube 120 is usually perpendicular to the axis of the small hole tube 120, when the end of the small hole tube 120 abuts against the radiating tube body 220, there is also an angle between the outlet end face of the small hole tube 120 and the radiating tube body 220, which will not affect the conduction of the small hole tube 120 when necessary.

[0048] In an optional embodiment, the burner 210 includes an inner tube 211, an outer tube 212, and an exhaust channel 213 disposed between the inner tube 211 and the outer tube 212. A retaining ring 214 is provided at one end of the inner tube 211 near the radiant inner tube 100. An air inlet is provided in the middle of the retaining ring 214. The interior of the radiant tube 220 is connected to the flue gas outlet through the exhaust channel 213.

[0049] In this embodiment, the fuel gas and the oxidizing agent (air) enter the burner 210 through the gas inlet and air inlet respectively. After mixing, they enter the inner tube 110 through the air inlet for continued combustion. The flue gas exiting the flue gas passage 230 is drawn into the inner tube 110 for circulation when the mixed gas enters it, and the remaining portion exits through the exhaust passage 213 from the flue gas outlet. The burner 210 includes an inner tube 211, an outer tube 212, and an exhaust passage 213. On one hand, it separates gases flowing in different directions; on the other hand, the flue gas can also heat the fuel gas and the oxidizing agent.

[0050] In an optional embodiment, the baffle ring 214 gradually tilts towards the direction of the radial inner tube 100 along the direction close to the axis of the inner tube 211, so that the flue gas tends to enter the exhaust channel 213 when it flows normally, and only moves along the baffle ring 214 to the inside of the inner tube body 110 when it is attracted by the combustion gas and the combustion-supporting gas.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A radiating inner tube, comprising an inner tube body, the inner tube body including an air inlet end and an air outlet end, characterized in that, The outer side of the inner tube is provided with a small perforated tube that communicates with the inside of the inner tube. The angle between the axis of the small perforated tube and the axis of the inner tube is 10°-20°, and the small perforated tube is inclined toward the air inlet end. Both the inner tube and the small perforated tube are made of heat-resistant metal. The perforated tubes are arranged in two or more rows along the circumference of the inner tube body, and each row of the perforated tubes includes two or more perforated tubes arranged along the axial direction of the inner tube body.

2. The radiating inner tube according to claim 1, characterized in that, The inner tube body is provided with ribs along the axial direction of the inner tube body, and there are two or more ribs arranged sequentially along the circumference of the inner tube body.

3. The radiating inner tube according to claim 1, characterized in that, The small-hole tubes are uniformly welded onto the inner tube body.

4. The radiating inner tube according to claim 1, characterized in that, The angle between the axis of the small-hole tube and the axis of the inner tube body is 15°.

5. The radiating inner tube according to claim 1, characterized in that, The heat-resistant metal is Cr25Ni35Nb heat-resistant cast steel.

6. A radiant tube, comprising a radiant tube body made of heat-resistant metal, wherein one end of the radiant tube body is closed and the other end is provided with a burner, the burner being provided with a gas inlet, an air inlet and a flue gas outlet, characterized in that, The radiant inner tube according to any one of claims 1-5 is disposed in the radiant tube body, the air inlet end of the inner tube body is close to the burner and a gap is provided between the inner tube body and the burner, the air outlet end of the inner tube body is close to the closed end of the radiant tube body and a gap is provided between the inner tube body and the radiant tube body, a flue gas passage is provided between the inner tube body and the radiant tube body, the air inlet end of the flue gas passage is connected to the air outlet end of the inner tube body, and the air outlet end of the flue gas passage is connected to the burner.

7. The radiant tube according to claim 6, characterized in that, The end of the small-hole tube away from the inner tube body abuts against the inner wall of the radiating tube body.

8. The radiant tube according to claim 7, characterized in that, The burner includes an inner tube, an outer tube, and an exhaust channel disposed between the inner tube and the outer tube. A baffle ring is provided at one end of the inner tube near the inner tube body, and an air inlet is provided in the middle of the baffle ring. The interior of the radiant tube body is connected to the flue gas outlet through the exhaust channel.

9. The radiant tube according to claim 8, characterized in that, The retaining ring gradually tilts towards the direction of the radiating inner tube along the direction close to the axis of the inner tube.

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