CN107664457B - Radiant tube type heating apparatus - Google Patents
Radiant tube type heating apparatus Download PDFInfo
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- CN107664457B CN107664457B CN201710623462.2A CN201710623462A CN107664457B CN 107664457 B CN107664457 B CN 107664457B CN 201710623462 A CN201710623462 A CN 201710623462A CN 107664457 B CN107664457 B CN 107664457B
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- radiant tube
- heat
- heat exchanger
- main body
- flow path
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
- F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
- F28D2021/0024—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for combustion apparatus, e.g. for boilers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
Abstract
The invention relates to a radiant tube heating device, comprising: a heat exchanger that is provided in a hollow portion of the other end portion side of the radiant tube and preheats air for combustion with heat of exhaust gas, wherein the heat exchanger includes: a ceramic main body having a cylindrical shape; an annular flange located at a base end portion of the heat exchanger; a flow path for heat dissipation for exhaust gas, which is formed spirally along an outer circumferential surface of the main body; a heat absorbing flow path for combustion air, which is spirally formed in the main body; and a return flow path for the preheated combustion air, which is formed in the central portion of the main body in the axial direction of the main body, an annular flange is clamped between the pair of facing pipe end faces via a relatively thick pair of annular packings located on the other end side of the radiant tube, and a tubular body having flexibility and heat insulating properties is provided continuously and coaxially with the opening portion on the base end side of the return flow path in the heat exchanger.
Description
Technical Field
The invention relates to a radiant tube heating device: which is capable of performing heating while maintaining a clean atmosphere in a heat treatment furnace, for example, and is excellent in thermal efficiency and durability.
Background
Heat exchangers for radiant tube burners have been proposed which comprise: a radiant tube penetrating a furnace wall of the annealing furnace and having a lying U-shape in a side view; a burner (combustion burner) disposed inside the distal (upstream) side of the radiant tube; and a heat exchanger disposed inside a rear end (downstream) side of the radiant tube. The heat exchanger preheats the combustion air to be supplied to the burner with heat contained in the combustion exhaust gas. The heat exchanger includes a heat exchanger main body and a heat exchange facilitating unit between the heat exchanger main body and the radiation pipe on the rear end side. The heat exchanger body is made of metal double tubes: it draws combustion air from the center side, makes a U-turn in its end portion, and then draws the combustion air to the outside. The heat exchange promoting unit is made of a copper-based heat conductor or heat sink and has a spiral shape (see, for example, patent document 1).
A radiant tube heating device is also proposed comprising: like a radiant tube as described above; a connection pipe arranged at one end (upstream) side of the radiant tube; and a burner disposed in a middle (central) portion of the connection pipe. The radiant tube heating apparatus further comprises: a waste gas return pipe connected to the other end (downstream) of the radiant tube; a SiC (ceramic) -based spiral heat exchanger surrounding the burner and introducing combustion air into a spiral-plate-shaped (helicalclate-shaped) ventilation chamber of the SiC (ceramic) -based spiral heat exchanger. The offgas return pipe communicates with the connection pipe, and the heat exchanger is arranged inside the connection pipe (see, for example, patent document 2).
The ceramic (SiC or the like) based spiral heat exchanger used in the radiant tube heating apparatus according to patent document 2 is excellent in heat resistance and thermal shock resistance. Therefore, this ceramic (SiC or the like) based spiral heat exchanger can be used so as to be arranged inside the rear end (downstream) side of the radiant tube as in the case of the heat exchanger of the radiant tube burner according to patent document 1.
However, for example, in the case of a metal tube-based radiant tube having a lying U-shape in side view, when distortion such as deformation in the form of a sag down of the furnace interior portion due to change over time, the radiant tube comes into contact with the SiC-based heat exchanger arranged inside the radiant tube at a plurality of places and exerts local stress and pressure on the SiC-based heat exchanger. As a result, brittle fracture may be generated in the vicinity of the flange on the rear end side of the SiC-based heat exchanger in some cases.
Patent document 1: JP-A-2014-92329
Patent document 2: JP-A-2013-one 194977
Disclosure of Invention
The present invention has been made to solve the above problems. The object of the present invention is to provide a radiant tube heating apparatus: the ceramic heat exchanger disposed inside the other end (downstream) side of the radiant tube is less likely to be brittle-broken even if the metal radiant tube is distorted due to time-based change or the like.
To achieve the object, the present invention has been made based on the following idea. One of the concepts is to give the following fillers a relatively large thickness: the packing presses a flange on the rear end side of the ceramic heat exchanger from both the pipe end faces, so that the ceramic heat exchanger is fixed to the other end (downstream) side in the radiant tube. Another idea is to prevent the following metal pipes from being inserted more into the heat exchanger than the flanges: the metal duct receives preheated combustion air drawn from a central portion of the heat exchanger.
The radiant tube heating apparatus (aspect 1) according to the present invention comprises:
a radiant tube having a turning part at a tip end side protruding into the furnace, and both end parts penetrating the furnace body;
a burner provided in a central portion of a hollow portion of one end side of the radiant tube and arranged coaxially with the hollow portion; and
a heat exchanger that is provided in a hollow portion of the other end side of the radiant tube and preheats combustion air with heat of exhaust gas,
wherein the heat exchanger comprises:
a ceramic main body having a cylindrical shape;
an annular flange located at a base end portion of the heat exchanger;
a flow path for heat dissipation for exhaust gas, which is formed spirally along an outer circumferential surface of the main body;
a heat absorbing flow path for combustion air, which is spirally formed in the main body; and
a return flow path for preheated combustion air formed in a central portion of the main body in an axial direction of the main body,
wherein the annular flange is clamped between a pair of pipe end faces facing each other via a pair of relatively thick annular packing on the other end side of the radiant tube, and
a tubular body having flexibility and heat insulation properties is provided continuously and coaxially with an opening portion of the base end side of the return flow path in the heat exchanger.
The following effects (1) and (2) can be achieved with the radiant tube type heating apparatus having the above-described configuration.
(1) In the ceramic heat exchanger, the annular flange in the base end portion thereof is clamped via a pair of relatively thick annular packings between a pair of pipe end faces facing each other in the other end portion of the radiant tube based on, for example, bolt and nut fastening. Therefore, even in the case where distortion occurs in a portion of the radiant tube inside the furnace (such as bending downward due to time-based change or the like), the heat exchanger can easily take a posture following the bending via the packing, and thus the possibility of brittle fracture of the heat exchanger in the vicinity of the flange can be largely eliminated or suppressed.
(2) A flexible and heat insulating tubular body is coaxially connected to an opening portion on the base end side of a return flow path for preheated combustion air in a heat exchanger. There is no metal pipe communicating with the inside of the return flow path. Therefore, even in the case where the distortion of the radiation pipe occurs as described above, the heat exchanger can easily and reliably follow the displacement in the vicinity of the flange of the heat exchanger via the tubular body. Therefore, the possibility of brittle fracture can be eliminated or reliably prevented.
The radiant tube may be a metal pipe made of cast steel or the like, and a distal end portion of the radiant tube may have a lying U shape or a lateral W shape.
The furnace body is, for example, a main furnace wall of a sintering furnace, a heat treatment furnace (such as an annealing furnace or the like), or the like. The furnace body may be the top of a heat treatment furnace or the like.
The burner burns the mixed gas of the preheated air and the fuel, and emits (discharges) an elongated flame to the hollow portion of the radiant tube in the axial direction of the hollow portion from an opening portion at the tip of the burner.
Examples of the ceramics constituting the heat exchanger include SiC, WC, B4C. Alumina (Al)2O3) Aluminum nitride, TiN and mullite. SiC is particularly recommended in view of excellent heat transfer coefficient and excellent thermal shock resistance.
The heat exchanger can be easily produced by using a three-dimensional (3D) printer even in the case where complicated inner and outer shapes are required.
The outer circumferential surface of the main body of the heat exchanger may be in contact with or in the vicinity of the inner wall surface of the hollow portion of the radiant tube.
The body of the heat exchanger has a terminal portion on the turn portion side of the radiant tube, the terminal portion having, for example, a hemispherical shape. A gas introduction groove communicating with the plurality of flow paths for heat dissipation may be located in the end portion.
The heat radiation flow path and the heat absorption flow path of the heat exchanger may be either a spiral groove or a spiral hollow portion (hole).
The filler is, for example, a sealing material stacked from a plurality of annular-shaped heat insulating materials containing paper-based ceramic fibers.
The invention also includes such radiant tube heating apparatus (aspect 2): wherein each of the pair of annular packing has an unloaded thickness of at least 9mm, and has a thickness of 4mm to 8mm in a state of clamping the annular flange of the heat exchanger.
According to this configuration, the annular flange of the ceramic heat exchanger is clamped via the annular packing having a thickness of at least 9mm, which is at least twice as thick as a common annular packing having a thickness of several millimeters (about 2mm to about 3mm), and which ranges from 4mm to 8mm when the annular flange is clamped. Therefore, even in the case where a portion of the radiant tube inside the furnace is distorted downward as described above, the above-described effect (1) can be reliably ensured.
The invention also includes such radiant tube heating apparatus (aspect 3): wherein the same number of the flow paths for heat dissipation and the flow paths for heat absorption are formed spirally and adjacent to each other in the outer peripheral surface and the inner peripheral surface of the main body, respectively, and the outer peripheral surface of the tubular body is surrounded by a metal cover having a plurality of claws protruding from a tip end surface thereof, and the claws are locked into opening portions of base end sides of the flow paths for heat absorption, respectively.
According to this configuration, the base end side of the flow path for heat absorption and the tubular body are allowed to be coaxial and reliably communicate with each other by the cover. Therefore, even in the case where the radiant tube is distorted as described above, the preheated air for combustion can be reliably supplied to the burner side at the one end side (effect (3)).
The covering member is obtained, for example, by punching and bending a thin stainless steel plate and then integrally forming the thin stainless steel plate into a cylindrical shape by welding or the like.
The invention also includes such radiant tube heating apparatus (aspect 4): wherein the tubular body is a cylindrical body made of a material containing a binder resin and a ceramic powder, or is formed of a plurality of annular members made of the material coaxially connected to each other.
According to this configuration, even in the case where the radiant tube is distorted as described above, the base end side of the flow path for heat absorption and the tubular body are allowed to reliably communicate with each other. Therefore, the above effects (2) and (3) can be reliably ensured.
The tubular body may be a tubular body using a cylindrical body made of a material containing a binder resin and a ceramic powder and a plurality of annular members made of the material simultaneously in a coaxial continuous manner.
Drawings
Fig. 1 is a vertical sectional view showing an embodiment of a radiant tube heating apparatus according to the present invention.
Fig. 2 is a perspective view of the heat exchanger disposed inside the other end side of the radiant tube.
Fig. 3 is a perspective view of the heat exchanger as viewed from the rear end side of the heat exchanger.
Fig. 4 is an enlarged vertical sectional view showing the other end side of the radiant tube type heating apparatus.
Fig. 5 is a perspective view showing an embodiment in which the tubular body and the cover are mounted on the rear end side of the heat exchanger.
Fig. 6A and 6B are partial enlarged views showing states before and after the flange of the heat exchanger is clamped on the other end side of the radiant tube via a pair of ring packings.
Description of reference numerals and symbols
1 radiant tube heating device
2 radiant tube
2a one end portion (upstream side)
2b other end (downstream side)
2c turning part
3 hollow part
13. 14 pipe end (pipe end)
20 heat exchanger
21 main body
21a return flow path
24 Heat radiating flow groove (flow path for heat radiation)
25 Heat absorbing flow hole (Heat absorbing flow path)
27 flange
28 opening part
30 tubular body
30r ring
32 cover
33 claw-like member
W furnace wall (furnace body)
P ring shaped packing
thickness of t1, t2 Ring Filler
Inside the IN furnace
OUT furnace outer part
Detailed Description
Next, embodiments of the present invention will be described.
Fig. 1 is a vertical sectional view showing an embodiment of a radiant tube type heating apparatus (hereinafter, simply referred to as a heating apparatus) 1 according to the present invention.
As shown in fig. 1, the heating apparatus 1 includes: a radiant tube 2 penetrating a vertical furnace wall (furnace body) W in a horizontal direction; a burner 4 provided coaxially with a central portion of the hollow portion 3 on the side of one end (upstream) 2a of the radiant tube 2; and a heat exchanger 20 provided in the hollow portion 3 on the other end (downstream) 2b side of the radiant tube 2.
The furnace wall W is, for example, a furnace body constituting a heat treatment furnace such as an annealing furnace.
The radiant tube 2 is, for example, a single piece made of cast steel and having the shape of a pipe. The radiant tube 2 has a substantially laid-down U-shape as a whole IN a side view, the radiant tube 2 penetrates the furnace wall W laterally from the furnace outside OUT toward the furnace inside IN, and the radiant tube 2 has a turning portion 2c protruding IN a semicircular shape (U-shape) at a tip end of the radiant tube 2 on the furnace inside IN side. The hollow portion 3 is formed continuously along the entire length of the radiant tube 2, covering the turning portion 2c and both ends of the end portions 2a and 2 b.
As shown in fig. 1, a heat radiator 17 (to be described later) made of ceramic is arranged between the turning part 2c and the heat exchanger 20 in the hollow part 3 of the radiation tube 2. The heat radiator 17 is made of an intermediate shaft 18 provided along a central portion of the hollow portion 3 and a heat radiation frame 19 spirally wound around the intermediate shaft 18.
The burned gas generated by the combustion of the fuel and the preheated combustion air IN the burner 4 heats the furnace interior IN via the tube wall of the radiant tube 2 while it passes through the turning section 2 c. The heat radiator 17 further transfers the heat of the burnt gas to the furnace interior IN side even after the burnt gas passes through the turning section 2c by allowing the burnt gas to flow spirally along the heat radiation frame 19.
The heat exchanger 20 is made of, for example, silicon carbide (SiC: carbon-based ceramic) having both excellent thermal conductivity and excellent thermal shock resistance. The heat exchanger 20 has an appearance shown in fig. 2 and 3 and a cross section shown in fig. 1 and 4. The heat exchanger 20 is manufactured by, for example, a 3D printer.
As shown in fig. 2 and 3, the heat exchanger 20 has a cylindrical main body 21, a hemispherical distal end portion 22, and a disk-shaped flange 27 on the rear end side of the main body 21. The main body 21, the tip portion 22 and the flange 27 are integral with each other. The gas introduction grooves 23 are symmetrically formed in the distal end portion 22 in the radial direction. The number of the gas introduction grooves 23 is six (plural) as an example in the present embodiment. Six (a plurality of) flow grooves for heat dissipation (flow paths for heat dissipation) 24 having a spiral shape and communicating with the six gas introduction grooves 23, respectively, are formed in parallel with each other in the outer peripheral surface of the main body 21.
The gas introduction groove 23 and the heat-radiating flow groove 24 are used to preheat the combustion air that has just been supplied into the burner 4 with the heat contained in the exhaust gas (burned gas that has passed through the heat radiator 17). Six recessed grooves 24a are provided on the flange 27 side of each heat dissipation flow groove 24 in parallel with the axial direction of the main body 21.
A return flow path (through hole) 21a having a columnar shape along the axial direction of the main body 21 is formed in a central portion of the main body 21. Six (a plurality of) flow holes for heat absorption (flow paths for heat absorption) 25 are formed in parallel with each other in an inner portion of the main body 21 around the return flow path 21 a. Each of the heat absorbing flow holes 25 has a spiral shape as a whole and has a cross section of an elongated rectangular shape.
As shown in fig. 1 and 4, six flow holes 25 for heat absorption and six flow grooves 24 for heat dissipation are alternately arranged in the axial direction of the main body 21. Each of the six heat absorbing flow holes 25 communicates with the return flow path 21a in the hollow portion inside the tip end portion 22. On the flange 27 side, each of the six heat absorbing flow holes 25 is a flow hole 25a parallel to the axial direction of the main body 21. The flow holes 25a and the grooves 24a are alternately formed in the circumferential direction of the main body 21. The six heat-absorbing flow holes 25 communicate with six opening portions 28, respectively, the six opening portions 28 being openings arranged along a circular shape on the base end side surface of the flange 27.
In the heat exchanger 20, as shown in fig. 4, a cylindrical sheet 26 formed of a heat insulating material is wound around the outer peripheral surface of the main body 21 between the outer peripheral surface of the main body 21 and the other end portion 2b side of the radiant tube 2. Therefore, leakage between the adjacent heat dissipation flow grooves 24 is prevented. In addition, the heat-resistant metal pipe 16 is inserted into the return path 21a substantially along the entire length of the return path 21a except for the tip end portion 22 side of the return path 21 a.
The discharge branch portion 15 communicating with the six heat-radiation flow grooves 24 is formed on the other end portion 2b side of the radiant tube 2. The exhaust duct 6 is vertically connected to the branch portion 15.
As shown in fig. 1 and 4, the periphery of the flange 27 of the heat exchanger 20 is pressed (clamped) via a pair of annular packings P, which are relatively thick and are arranged in the left-right (front-rear) direction in the drawing, between the pipe end portion (pipe end surface) 14 on the other end portion 2b side of the radiant tube 2 and the pipe end portion (pipe end surface) 13 of the L-shaped pipe 12 connected to the air supply pipe 11.
The annular packing P is, for example, a sealing material stacked by a plurality of annular-shaped heat insulating materials formed of paper-based ceramic fibers. As shown in fig. 6A, the annular packing P has a thickness t1 of at least 9mm when unloaded.
As shown in fig. 6B, when the flange 27 of the heat exchanger 20 is fastened between the pipe portion 13 and the pipe portion 14 using a plurality of bolts B and a plurality of nuts n, the thickness of each of the annular packing P ranges from about 4mm to about 8 mm.
A plurality of through holes 13h and 14h parallel to the axial direction are formed through the pipe ends 13 and 14. In a state where the peripheral portion of the flange 27 is superimposed with the pair of annular packing P, once the bolts b are inserted into the through holes 13h and 14h and the nuts n are screwed with the tip end sides of the male screw portions of the bolts b, the peripheral portion of the flange 27 can be fastened via the annular packing P from both sides of the peripheral portion of the flange 27. As a result, the heat exchanger 20 is placed in a fixed state in the hollow portion 3 on the other end portion 2b side of the radiant tube 2.
As shown in fig. 6B, it is desirable to form a slight gap between the outer peripheral side of the flange 27 and the inner peripheral portions of the pipe ends 13 and 14.
As shown in fig. 1, a horizontal portion 7 of a supply pipe 8 for supplying air for combustion is laid inside an L-shaped pipe 12. A tubular body 30 having flexibility and thermal insulation is coaxially arranged between the inside of the horizontal portion 7 and the return flow path 21a of the heat exchanger 20. As shown in fig. 4 and 5, the tubular body 30 is a cylindrical body in which a plurality of annular members 30r are coaxially connected to each other, wherein each of the annular members 30r is obtained by molding ceramic powder containing a binder resin. The tubular body 30 has a hollow portion 31 inside, and the hollow portion 31 communicates with the return flow path 21a of the heat exchanger 20. The plurality of ring-like members 30r form the tubular body 30 by being bonded to each other.
As shown in fig. 4 and 5, the tubular body 30 is inserted into an inner side 35 of the metal cover 32 around an outer circumferential surface of the tubular body 30 and supported by the inner side 35 of the metal cover 32. The cover 32 has six (a plurality of) claws 33 protruding from the tip end surface 34 side of the cover 32. The cover 32 is mounted on the outside of the flange 27 by inserting and locking six (a plurality of) claws 33 respectively into six opening portions 28 that open in the rear end face of the flange 27 of the heat exchanger 20.
In other words, the metal pipe 16 inserted in the return flow path 21a of the heat exchanger 20 and the horizontal portion 7 of the supply pipe 8 for supplying air for combustion communicate with each other via the tubular body 30.
As shown in fig. 1, a supply duct 8 for supplying air for combustion can communicate with a holder 9 supported by an end plate 5 via a bellows 10. The end plate 5 shields the pipe end on the one end portion 2a side of the radiation pipe 2, and the corrugated pipe 10 is made of a heat-resistant material and can be stretched in the vertical direction. The holder 9 penetrates the end plate 5 that shields the end face of the pipe in the one end portion 2a, and the burner 4 is mounted at the tip of the holder 9. The holder 9 draws combustion gas, which is obtained by mixing previously atomized fuel with preheated combustion air, into the burner 4 and performs ignition. As a result, the flame F shown in fig. 1 is ejected from the burner 4.
Next, the effect of the heating apparatus 1 will be described.
As shown in fig. 1, once a flame F is ejected from the burner 4 in the hollow portion 3 on the one end portion 2a side of the radiation pipe 2, burned gas heated by the flame F is generated. The burned gas flows through the turning portion 2c and the vicinity of the heat radiator 17 as indicated by white arrows shown in fig. 1, and is supplied to the heat exchanger 20 on the other end portion 2b side. During this supply of the burned gas, the heat contained IN the burned gas is radiated as radiant heat to the furnace interior IN via the tube wall of the radiant tube 2, and is used for heating the furnace interior IN to maintain a predetermined temperature range. The radiation of the radiant heat is promoted by the burnt gas that passes spirally through the heat radiator 17.
As indicated by gray arrows shown in fig. 1 and 4, the burned gas supplied to the distal end portion 22 of the heat exchanger 20 in the hollow portion 3 on the other end portion 2b side of the radiant tube 2 passes through six gas introduction grooves 23 and six spiral heat-radiation flow grooves 24 communicating with the six gas introduction grooves 23, respectively. Then, the burned gas is discharged from the exhaust duct 6 to the outside.
Combustion fresh air passes from the air supply duct 11 through the L-shaped duct 12 as indicated by the thin white arrows shown in fig. 1 and 4. Then, the new air for combustion is drawn into the plurality of opening portions 28 that open in the flange 27 of the heat exchanger 20. The combustion fresh air passes through the straight flow hole 25a and the spiral heat-absorbing flow hole 25, and is sent into the hollow portion inside the tip end portion 22. The new combustion air is gradually preheated (heated) by heat transfer from the burned gas flowing through the plurality of flow grooves for heat dissipation 24 adjacent to each other with the plurality of flow holes for heat absorption 25 during the passage through the plurality of flow holes for heat absorption 25.
As indicated by thin white arrows, preheated combustion air is supplied from the hollow portion inside the tip end portion 22 of the heat exchanger 20 through the inside of the metal pipe 16 inserted into the return flow path 21a into the hollow portion 31 of the tubular body 30 communicating with the outside of the flange 27. After passing through the tubular body 30, the combustion air passes through the supply duct 8 including the horizontal portion 7, the bellows 10 and the holder 9. Then, the combustion air is supplied into the combustor 4 and mixed with the fuel, and a flame F is generated.
IN the case of repeating the above operation for a long period of time, the furnace interior IN side including the turning portion 2c of the radiant tube 2 is distorted such as a slight downward sinking IN some cases. For example, in some cases, this form of distortion deformation occurs: the vicinity of the turning portion 2c of the radiant tube 2 undergoes displacement of several millimeters toward the lower side.
In the present embodiment, as shown in fig. 4 and 6B, the flange 27 of the heat exchanger 20 is clamped between the annular packing P between the pipe end 14 located in the other end 2B of the radiant tube 2 and the pipe end 13 of the L-shaped pipe 12. The ring packing P has a relatively large unloaded thickness t1 and a reduced thickness t2 of about 1mm to about 5mm due to being fastened by the bolt b and the nut n.
As a result, in the case where the radiant tube 2 is subjected to distortion deformation as described above, the flange 27 and the main body 21 of the heat exchanger 20 can easily follow the hollow portion 3 in the other end portion 2b of the radiant tube 2 subjected to distortion within the variation range of the thickness of the pair of annular packing P. For example, the annular packing P adjacent to the pipe end 14 is changed such that its upper portion side is significantly compressed and its lower portion side is slightly contracted, and the annular packing P adjacent to the pipe end 13 is changed such that its upper portion side is slightly contracted and its lower portion side is significantly compressed.
Therefore, the above-described effects (1) to (3) can be reliably achieved with the heating apparatus 1. IN addition, even IN the case where the furnace interior IN side of the radiant tube 2 is subjected to a relatively large earthquake causing vertical sway, the above-described effects (1) to (3) can be achieved. In this connection, it can be said that the heating apparatus 1 is durable and is not easily damaged even for a relatively large earthquake.
The present invention is not limited to the above-described embodiments.
For example, the outer shape of the turning portion 2c of the radiant tube 2 may be a lateral M-shape (substantially Σ -shape) or a lateral W-shape.
The heat exchanger 20 may be made of ceramics excellent in thermal conductivity and thermal shock resistance other than SiC.
The profile of the end portion 22 of the heat exchanger 20 may be tapered or semi-elliptical.
The heat-dissipating fluid groove 24 of the heat exchanger 20 may be a heat-dissipating fluid hole 24 of: which is a helical hollow bore arranged inside the body 21 and has a similar shape as described previously.
The metal pipe 16 inserted into the return path 21a of the heat exchanger 20 may be omitted. Alternatively, the metal pipe 16 may be used, and the heat absorbing flow hole 25 may be such a heat absorbing flow groove 25: which is open to the side of the return flow path (through hole) 21a and has a shape similar to that described previously.
The tubular body 30 may be an integral cylindrical body: which is made of the above-mentioned material and has a hollow part 31 in the interior of the cylindrical body. Alternatively, a cylindrical body and a plurality of ring members 30r may be arranged coaxially and continuously.
The tubular body 30 may be mounted on the flange 27 in such a manner that one end (tip) side of the tubular body 30 is inserted into the return flow path 21a of the heat exchanger 20 or the metal pipe 16. In this case, a tubular body 30 having a reduced outer diameter and a cover 32 having a reduced inner diameter are used, and a claw 33 protrudes from a large-diameter portion of the cover 32.
Industrial applicability
According to the present invention, it is possible to reliably provide a radiant tube heating apparatus: even in the case where the metal radiant tube is distorted by a change over time or the like, the ceramic heat exchanger disposed inside the other end (downstream) side of the radiant tube is less likely to be brittle-broken.
Although the embodiments of the present invention have been described in detail above, the present invention should not be construed as being limited to the above-described embodiments in any way, and it is apparent that various modifications and variations can be made without departing from the spirit and scope of the invention.
The present application is based on Japanese patent application No.2016-148912, filed 2016, 7, 28, and the contents of which are incorporated herein by reference.
Claims (3)
1. A radiant tube heating apparatus comprising:
a radiant tube having a turning part at a distal end side thereof protruding into the furnace, and both ends of the radiant tube penetrating through the furnace body;
a burner provided in a central portion of a hollow portion of one end side of the radiant tube and arranged coaxially with the hollow portion; and
a heat exchanger that is provided in a hollow portion of the other end side of the radiant tube and preheats combustion air with heat of exhaust gas,
wherein the heat exchanger comprises:
a ceramic main body having a cylindrical shape;
an annular flange located at a base end portion of the heat exchanger;
a flow path for heat dissipation for exhaust gas, which is formed spirally along an outer circumferential surface of the main body;
a heat absorbing flow path for combustion air, which is spirally formed in the main body; and
a return flow path for preheated combustion air formed in a central portion of the main body in an axial direction of the main body,
wherein the annular flange is clamped between a pair of pipe end faces facing each other via a pair of relatively thick annular packings located on the other end side of the radiant tube,
a tubular body having flexibility and heat insulating property is provided continuously and coaxially with an opening portion of a base end side of the return flow path in the heat exchanger, and
wherein each of the pair of annular packing has an unloaded thickness of at least 9mm, and each of the pair of annular packing has a thickness of 4mm to 8mm in a state of clamping the annular flange of the heat exchanger.
2. Radiant tube heating device according to claim 1,
wherein the same number of the flow paths for heat dissipation and the flow paths for heat absorption are formed spirally and adjacent to each other in the outer peripheral surface and the inner peripheral surface of the main body, respectively, and
an outer peripheral surface of the tubular body is surrounded by a metal cover having a plurality of claws protruding from a tip end surface thereof, and the claws are locked into respective opening portions on a base end side of the flow path for heat absorption, respectively.
3. Radiant tube heating apparatus according to claim 1 or 2,
wherein the tubular body is a cylindrical body made of a material containing a binder resin and a ceramic powder, or is formed of a plurality of annular members made of the material coaxially connected to each other.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016148912A JP6790554B2 (en) | 2016-07-28 | 2016-07-28 | Radiant tube type heating device |
| JP2016-148912 | 2016-07-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107664457A CN107664457A (en) | 2018-02-06 |
| CN107664457B true CN107664457B (en) | 2020-03-10 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201710623462.2A Active CN107664457B (en) | 2016-07-28 | 2017-07-27 | Radiant tube type heating apparatus |
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| JP (1) | JP6790554B2 (en) |
| CN (1) | CN107664457B (en) |
| TW (1) | TWI628406B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4073448A4 (en) * | 2019-12-12 | 2023-12-13 | Saint-Gobain Ceramics & Plastics Inc. | Heat exchanger component with varying twist angle |
| KR102321280B1 (en) * | 2020-03-31 | 2021-11-03 | 한국에너지기술연구원 | Heat-rising apparatus of superheated steam with pipe for preventing heat loss |
Citations (5)
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|---|---|---|---|---|
| US4589844A (en) * | 1984-07-25 | 1986-05-20 | Advanced Combustion Inc. | Heat exchange apparatus for industrial furnaces |
| KR20060028836A (en) * | 2004-09-30 | 2006-04-04 | 한국에너지기술연구원 | Self regenerative type single radiant tube burner |
| CN201748425U (en) * | 2010-08-25 | 2011-02-16 | 常熟喷嘴厂有限公司 | Radiant tube burner |
| CN102149971A (en) * | 2008-09-10 | 2011-08-10 | 法孚斯坦因公司 | Recuperator for a radiating tube burner |
| JP2014092329A (en) * | 2012-11-06 | 2014-05-19 | Jfe Steel Corp | Heat exchanger for radiant tube burner |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5576786B2 (en) * | 2010-12-29 | 2014-08-20 | 東邦瓦斯株式会社 | Regenerative Radiant Tube Burner |
| JP5965170B2 (en) * | 2012-03-19 | 2016-08-03 | 新和企業株式会社 | Radiant tube heating device |
| CN202993212U (en) * | 2012-11-23 | 2013-06-12 | 佛山市科皓燃烧设备制造有限公司 | Spiral pipe type pre-heater special for burner |
| CN203215677U (en) * | 2013-03-14 | 2013-09-25 | 宝山钢铁股份有限公司 | Heat exchanger for radiant tube |
| US10458646B2 (en) * | 2014-09-25 | 2019-10-29 | Selas Heat Technology Company Llc | Low NOx, high efficiency, high temperature, staged recirculating burner and radiant tube combustion system |
-
2016
- 2016-07-28 JP JP2016148912A patent/JP6790554B2/en active Active
-
2017
- 2017-07-27 CN CN201710623462.2A patent/CN107664457B/en active Active
- 2017-07-27 TW TW106125290A patent/TWI628406B/en active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4589844A (en) * | 1984-07-25 | 1986-05-20 | Advanced Combustion Inc. | Heat exchange apparatus for industrial furnaces |
| KR20060028836A (en) * | 2004-09-30 | 2006-04-04 | 한국에너지기술연구원 | Self regenerative type single radiant tube burner |
| CN102149971A (en) * | 2008-09-10 | 2011-08-10 | 法孚斯坦因公司 | Recuperator for a radiating tube burner |
| CN201748425U (en) * | 2010-08-25 | 2011-02-16 | 常熟喷嘴厂有限公司 | Radiant tube burner |
| JP2014092329A (en) * | 2012-11-06 | 2014-05-19 | Jfe Steel Corp | Heat exchanger for radiant tube burner |
Also Published As
| Publication number | Publication date |
|---|---|
| JP6790554B2 (en) | 2020-11-25 |
| TW201809580A (en) | 2018-03-16 |
| JP2018017470A (en) | 2018-02-01 |
| CN107664457A (en) | 2018-02-06 |
| TWI628406B (en) | 2018-07-01 |
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