JP2005241144A - Radiant tube type heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiant tube type heating device comprising a practical supporting means with a simple structure to mount a deformed radiant tube in an inverted state, and elongating a service life of the radiant tube. <P>SOLUTION: In this heating device, heat accumulation alternate combustion type burners 7, 8 are mounted on the W-type radiant tube 2, a ring-shaped member 13 is mounted on a main body part 11a of a projecting part 11 fixed to an U-shaped bent part 2a of the radiant tube 2, and the radiant tube 2 is supported by bringing the ring-shaped member 13 into contact with a floor face 14a of a supporting hole part 14 formed on an inner wall face 20a of a heating furnace 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radiant tube heating device disposed in a heating furnace such as a heat treatment furnace.

  The radiant tube type heating device is a heating device including a radiant tube (radiant heat transfer tube) as a heat source, and is disposed in a heat treatment furnace such as a non-oxidation furnace. The radiant tube is usually made of a U-shaped tube obtained by bending a heat-resistant alloy into a U shape, a W-shaped tube bent into a W shape, or the like.

  FIG. 8 shows a state in which a W-shaped radiant tube is arranged in a heating furnace as a representative example. In the figure, reference numeral 2 denotes a radiant tube, and includes a support portion 64 provided on the furnace wall surface 20a of the heating furnace 20 and a protruding portion 67 protruding from the top of the U-shaped bent portion 2a of the radiant tube 2. A large number are arranged across the furnace width direction of the heating furnace 20 (left-right direction in FIG. 8).

  The radiant tube 2 is heated by burning fuel such as kerosene and gas inside the radiant tubes 2, and the material to be heated is heated by radiant heat from the outer surface of the radiant tube 2. According to the heating furnace using such a radiant tube 2, since the furnace atmosphere gas is not contaminated, the material to be heated can be heated in a stable atmosphere.

  This radiant tube 2 is thermally expanded by being heated, and the dimensional change particularly in the furnace width direction becomes remarkable. Therefore, if the radiant tube 2 is fixed to the support part 64, stress will act on the radiant tube 2 by the thermal expansion accompanying heating, and the radiant tube 2 will be damaged depending on the degree of thermal expansion. Therefore, the radiant tube 2 is supported so that it can be displaced in the furnace width direction.

  For example, as shown in FIG. 8, the radiant tube 2 has three projecting portions 67 projecting from the apexes of the three U-shaped bent portions 2a mounted on a support portion 64 provided on the furnace wall surface 20a. Has been supported. A semi-cylindrical portion 67 a is provided on the contact surface between the protruding portion 67 and the support portion 64. Thereby, when the radiant tube 2 is thermally expanded, the projecting portion 67 can slide in the furnace width direction with respect to the support portion 64 while the hemispherical portion 67a is in contact with the upper surface of the support portion 64. It was.

  By the way, when the radiant tube 2 is used for a certain period of time, the radiant tube 2 is gradually deformed due to oxidation thinning and its own weight, and eventually becomes in a state as shown in FIG. In such a state, the projecting direction of the projecting portion 67 projecting from the nodal point of the U-shaped bent portion 2a changes and collides with the end portion of the support portion 64 provided on the furnace wall surface 20a. Thus, even if the radiant tube 2 tries to thermally expand in the furnace width direction, the displacement of the radiant tube 2 in the furnace width direction is restricted. For this reason, the energy of thermal expansion acts on the radiant tube 2 and the radiant tube 2 is bent early. As a result, the life of the radiant tube 2 which is originally determined by the oxidation thinning is remarkably shortened.

  If the bent radiant tube 2 can be mounted upside down, the life of the radiant tube 2 can be extended. However, when the bent radiant tube 2 is installed upside down, as shown in FIG. Thus, the size of the joint between the protruding portion 67 and the support portion 64 changes, and the protruding portion 67 cannot be supported by the support portion 64 via the semi-cylindrical portion 67a.

  In view of this, a support structure for a radiant tube has been proposed in which the radiant tube can be attached upside down even when the radiant tube is bent (see, for example, Patent Document 1).

  FIG. 5 is a view showing a support structure for a radiant tube described in Patent Document 1, FIG. 5 (a) is a front view, FIG. 5 (b) is a top view of the main part, and FIG. It is a front view of the principal part. The support structure of the radiant tube extends in the furnace width direction in the vicinity of the apex of the U-shaped bent portion 2a of the radiant tube 2 arranged so as to be substantially symmetrical in the vertical direction. A projecting portion 51 having a vertically symmetrical shape that protrudes and is fixed, and a support portion 54 that is fixed to the inner wall surface 20a of the heating furnace 20 and supports the projecting portion 51 by being mounted thereon. A round bar 53 is attached to the main body 51a of the projecting portion 51, and the support 54 is constituted by support bars 54a and 54b for mounting and supporting both ends 53a and 53b of the round bar 53, respectively. Yes.

As shown in FIG. 6, when the radiant tube 2 is bent, as shown in FIG. 7, even if the radiant tube 2 is installed upside down, the mating dimension between the round bar 53 and the support portion 54 is small. Since it does not change, the protruding portion 51 can be supported by the support portion 54, and the life of the radiant tube 2 can be extended to the same extent as that due to oxidation thinning.
JP-A-11-257612

  However, as shown in Patent Document 1, the round bar 53 is attached to the main body 51a of the projecting part 51 sideways, and both ends 53a and 53b of the round bar 53 are supported by the support bars 54a and 54b. The support structure is a rather complicated support structure, and the round bar 53 is attached to the main body 51a of the projecting portion 51 at several hundreds in a horizontal direction, and the wall 54a is also attached to the support 54 at several hundreds at the same. Considering the cost for attaching the support rods 54a and 54b and the opportunity loss due to the construction, it is not practical to use a radiant tube heating device having such a support structure.

  The present invention has been made in view of the circumstances as described above, and includes a practical support means with a simple structure, so that a deformed radiant tube can be installed upside down, and the length of the radiant tube is increased. It is an object of the present invention to provide a radiant tube type heating device capable of extending the service life.

  The inventor of the present invention has a complicated structure for supporting the radiant tube shown in Patent Document 1 on the assumption that the radiant tube is deformed on the premise of one-side combustion in which one burner burns from one side. This is because it is assumed that the amount of deformation is large and asymmetrical, and if the heat storage alternating combustion type radiant tube heating device that repeats combustion and heat storage alternately with two heat storage burners installed above and below, Since the temperature difference between the upper and lower sides is small, the deformation of the radiant tube is almost vertically symmetrical and the amount of deformation is reduced, the idea that the radiant tube can be installed upside down even with a simple support structure has been reached, and further studies Thus, the present invention has been completed.

  In order to solve the above-described problems, the present invention has the following features.

  [1] A radiant tube arranged so as to be substantially symmetrical in the vertical direction of the heating furnace, and a regenerative alternating combustion burner attached to the upper and lower openings of the radiant tube, A support means for supporting the radiant tube in the furnace, the support means being fixed in the vicinity of the apex of the U-shaped bent part of the radiant tube and projecting in the furnace width direction, and heating A support hole into which the projecting portion is inserted and opened in the inner wall surface of the furnace, and the projecting portion includes a ring-shaped member that contacts the floor surface of the support hole and is vertically symmetrical A radiant tube heating device characterized by having a shape.

  [2] The radiant tube heating device according to [1], wherein the outer surface of the ring-shaped member has an arc shape in the furnace width direction.

  In the present invention, as a heat storage alternating combustion type radiant tube, the amount of deformation of the radiant tube is suppressed, and the projecting portion of the radiant tube is made symmetrical in the vertical direction as a support means of the radiant tube. Since the ring-shaped member is attached to the part and this ring-shaped member is brought into contact with the floor surface of the support hole, the projecting portion can slide in the furnace width direction and absorb the thermal expansion of the radiant tube. The deformed radiant tube can be mounted upside down.

  That is, the deformed radiant tube can be installed upside down by a simple and practical support means in which a ring-shaped member is attached to the projecting portion and the ring-shaped member is brought into contact with the floor surface of the support hole. This makes it possible to extend the life of the radiant tube and greatly reduce the maintenance and replacement costs of the radiant tube.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a front view showing a radiant tube heating device according to an embodiment of the present invention. FIG. 2 is a three-sided view showing the radiant tube support means in this radiant tube type heating device, wherein FIG. 2 (a) is a top view, FIG. 2 (b) is a front view, and FIG. 2 (c) is a front view. It is a side view.

  In FIG. 1, a radiant tube is arranged so as to be extended in the furnace width direction of the heating furnace 20 so that 2 is substantially symmetric in the vertical direction. Here, a W-shaped radiant tube is used.

  Further, regenerative alternating combustion burners 7 and 8 are attached to upper and lower openings of the radiant tube 2, respectively. Reference numeral 9 denotes a control unit for switching between combustion and heat storage of the heat storage alternating combustion burners 7 and 8.

  And in order to support the radiant tube 2 in a furnace, the support means 10 provided in the vertex vicinity of the U-shaped bending part 2a of the radiant tube 2 is provided. Since the radiant tube 2 of this embodiment is W-shaped, it has three U-shaped bent portions 2a, and three support means 10 are also provided. All of these support means 10 have the same structure.

  As shown in FIG. 2, the support means 10 is fixed to the vicinity of the apex of the U-shaped bent portion 2 a of the radiant tube 2 and protrudes in the furnace width direction, and opens to the inner wall surface 20 a of the heating furnace 20. And a support hole portion 14 into which the protruding portion 11 is inserted.

  The main body portion 11a of the projecting portion 11 has a circular cross-sectional shape and is joined to the mounting member 12 by welding or the like. The mounting member 12 is welded or the like near the nodal point of the U-shaped bent portion 2a of the radiant tube 2. Are joined by. A ring-shaped member 13 is attached to the distal end side of the main body 11a. Thereby, the projecting portion 11 has a symmetrical shape with respect to the vertical direction and the furnace length direction.

  And the front end side of the main-body part 11a of the protrusion part 11 is inserted in the support hole part 14 currently opened to the inner wall face 20a of the heating furnace 20, and the ring-shaped member 13 contact | abuts to the floor surface 14a of the support hole part 14. FIG. Thus, the protruding portion 11 is supported.

  In the radiant tube type heating device configured as described above, the radiant tube 2 is heated by burning fuel such as kerosene and gas inside the radiant tube 2 by the regenerative alternating combustion burners 7 and 8. The material to be heated is heated by radiant heat from the outer surface of 2.

  At that time, when the radiant tube 2 is heated and thermally expanded, the ring-shaped member 13 of the projecting portion 11 slides in the furnace width direction while coming into contact with the floor surface 14a of the support hole portion 14, thereby Absorbs thermal expansion.

  A case where the radiant tube 2 is deformed by use for a certain period will be described with reference to FIG.

  First, in this embodiment, since the heat storage alternating combustion type radiant tube that repeats combustion and heat storage alternately by the two heat storage burners 7 and 8 installed at the top and bottom, the temperature difference between the top and bottom of the radiant tube 2 is The deformation of the radiant tube 2 is almost symmetric and the amount of deformation is small.

  Even if the radiant tube 2 is slightly deformed and descends downward, the ring-shaped member 13 is pivoted about the support hole portion 14 because the main body portion 11a of the projecting portion 11 rotates with the ring-shaped member 13 serving as a fulcrum. When the radiant tube 2 continues to abut against the floor surface 14a and thermally expands, the ring-shaped member 13 of the projecting portion 11 slides in the furnace width direction while abutting against the floor surface 14a of the support hole portion 14, whereby the radiant Absorbs the thermal expansion of the tube 2.

  Thus, even if the radiant tube 2 is somewhat deformed, the radiant tube 2 can be appropriately supported while absorbing the displacement of the radiant tube 2 in the furnace width direction.

  Next, when the predetermined use period has passed, the deformed radiant tube 2 is installed upside down as shown in FIG. Although the deformation of the radiant tube 2 is small because of the regenerative combustion type, if the radiant tube 2 is used for a long period of time as shown in FIG. 3, the deformation of the radiant tube 2 will increase. This is because there is a risk that the bottom surface of the radiant tube 2 is locally damaged by heat in the vicinity of the flame front ends of the burners 7 and 8.

  In FIG. 4, even if the deformed radiant tube 2 is installed upside down, the relative positional relationship between the projecting portion 11 and the support hole portion 14 which are the shapes of the upper and lower objects does not change. Thus, the protruding portion 11 can be supported via the ring-shaped member 13.

  As described above, according to this embodiment, the ring-shaped member 13 is mounted on the main body portion 11 a of the projecting portion 11, and the ring-shaped member 13 is brought into contact with the floor surface 14 a of the support hole portion 14. With the support means, the deformed radiant tube 2 can be installed upside down, the life of the radiant tube 2 can be extended, and the maintenance and replacement costs of the radiant tube 2 can be greatly reduced.

  In this embodiment, a W-shaped radiant tube is used. However, a radiant tube that is arranged in the furnace width direction of the heating furnace so as to be substantially symmetrical in the vertical direction may be used. In addition to the shape, it is a U-shaped radiant tube.

  In this embodiment, the projecting portion has a main body portion having a circular vertical cross-sectional shape, but has a ring-shaped member that comes into contact with the floor surface of the support hole portion and exhibits a vertically symmetrical shape. If there is, the shape does not matter at all.

  Further, if the outer surface of the ring-shaped member is formed in an arc shape in the furnace width direction, it can be smoothly rotated when the main body portion of the projecting portion rotates along with the deformation of the radiant tube.

  Furthermore, if a sliding material that reduces the contact resistance is provided at a location where the ring-shaped member and the floor surface of the support hole contact, stress acting on the radiant tube can be reduced, and deformation can be suppressed as much as possible.

It is a front view showing one embodiment of the present invention. It is a figure which shows the support means in one Embodiment of this invention. In one Embodiment of this invention, it is a front view which shows a state when a radiant tube deform | transforms. In one Embodiment of this invention, it is a front view which shows the state which attached the deformed radiant tube upside down. It is a figure which shows the support structure of the radiant tube described in Unexamined-Japanese-Patent No. 11-257612. It is a figure which shows the state which the radiant tube shown in FIG. 5 bent. It is a figure which shows the state which attached the radiant tube which was bent in FIG. 6 upside down. It is a figure which shows the support horizontal construction of the conventional radiant tube. It is a figure which shows the state which the radiant tube shown in FIG. 8 bent. It is a figure which shows the state which attached the radiant tube of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Radiant tube 2a U-shaped bending part 7, 8 Thermal storage alternating combustion type burner 9 Control part of thermal storage alternating combustion type burner 10 Support means 11 Protruding part 11a Main part of protruding part 12 Mounting member 13 Ring-shaped member 14 Support hole Part 14a Floor surface of support hole 20 Heating furnace 20a Inner wall surface of heating furnace

Claims (2)

  A radiant tube arranged so as to be substantially symmetric in the vertical direction of the heating furnace, a regenerative alternating combustion burner attached to upper and lower openings of the radiant tube, and the radiant tube Supporting means for supporting the inside of the furnace, the supporting means being fixed in the vicinity of the apex of the U-shaped bent portion of the radiant tube and projecting in the furnace width direction, And a support hole portion into which the projecting portion is inserted. The projecting portion includes a ring-shaped member that comes into contact with the floor surface of the support hole portion and exhibits a vertically symmetrical shape. A radiant tube heating device characterized by the above.   The radiant tube heating device according to claim 1, wherein the outer surface of the ring-shaped member has an arc shape in the furnace width direction.

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