JPS61173018A - Smoke tube for radiant-heat transfer tube with mantle - Google Patents

Abstract

1. An outer radiant heating tube for an industrial burner having a ceramic flame tube (3) consisting at least partially of individual ceramic tube portions (7, 7a) which are interconnected positively at their ends and with which externally disposed rib-like or cam-like spacing members (14, 16) are associated for radial bearing against an outer tube (1) enclosing the flame tube, each of the tube portions being formed at one end as a socket (8) and having at the other end a cylindrical zone (9) fitting into such socket, characterized in that adjoining tube portions (7, 7a) are inserted into one another with clearance at the socket connecting places, and fitted with clearance on to the outside of the flame tube (3) in the zone of each of the socket connecting places is a ceramic covering ring (11) which is positively fixed to the flame tube (3) in the axial direction, extends in the axial direction over a portion of the cylindrical zone (9) of each tube portion (7, 7a) and is at least partially covered by the associated socket (8).

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention includes spacers each protruding from the outer periphery,
At least 1al is a smoke tube that is made of ceramic and includes tube members connected to each other at their ends, and is incorporated into a radiant heat exchanger tube with a mantle, and the spacer is formed to support a mantle tube surrounding the smoke tube. This invention relates to a smoke tube for a radiant heat transfer tube with a mantle used in an industrial burner.

[Prior Art] The above-mentioned smoke tube for radiant heat transfer is already known, and the smoke tube can withstand the large thermal loads that occur during burner operation, especially when the burner starts and stops, without reducing its service life. It is superior in that it can operate smoothly regardless of the situation. An example □ is described in Eida Patent Publication No. 716579. In this example, a ceramic tube is used that runs the entire length of the flue.

The mantle-equipped radiant heat exchanger tube of the prior art has a high risk of breakage, especially when it is installed laterally. The reason for this is that the cast metal mantle that surrounds the smoke pipe at intervals not only changes in length but also flexes to some extent when affected by temperature. This is because ceramic flues, which are integrally formed and have relatively high rigidity, cannot withstand changes and deflections.

British Patent Publication No. 564 523 and U.S. Patent Publication No. 2478 732 disclose an invention that provides a certain degree of elasticity to ceramic smoke pipes, which is a cylindrical tube member that is assembled loosely and coaxially at the end. Alternatively, a smoke pipe is formed by an annular ring portion. In order to ensure that the pipe parts can be moved relative to each other at the connection point, notches and springs formed in the end faces of the pipe parts are used, in this case radially outward in a plane perpendicular to the pipe axis. An annular gap is formed that opens to the . If the annular gap between the two pipe members that are in close contact with each other becomes even partially open due to various changes in the length of the metal mantle pipe and ceramic chimney pipe, or due to deflection of the mantle pipe, ,
A stream of hot flame gases is generated from the inside of the flue to the outside, traveling radially and impinging on the metal mantle tube.

The mantle tube, whose inner circumferential surface is constantly exposed to the fairly cold exhaust gas flowing from the annular space between the inside of the mantle tube and the smoke pipe, is immediately destroyed as it is subjected to a large thermal overload due to partial overheating by the flame gas. Or, even if it does not result in destruction, it may cause some sort of functional decline. This is the same even within the life span corresponding to normal operation.

It is already known that relatively thick-walled ceramic tube members or annular rings are susceptible to cracking under the influence of various temperatures on the inside and outside.

In this sense, it can be said that a structure in which a connection point consisting of an annular ring part is assembled using a number of fan-shaped parts, as in the case of West German Patent Publication No. 1551 762, is well known. In order to avoid the above-mentioned disadvantages, ceramic smoke pipes have been developed that are relatively small and are assembled with parts that do not change sensitively to large temperature gradients, and are highly flexible. To achieve this, the individual parts were joined together by ceramic sealing cement, which resulted in the disadvantage of high costs and the inconvenience that if the ceramic parts were damaged, the entire flue pipe had to be replaced. This is because even if a part of the parts bonded with the sealing cement is damaged, only that part cannot be replaced.

[Problems to be Solved by the Invention] The problems to be solved by the present invention are to provide a simple structure, which can prevent local overheating from occurring in the metal mantle tube surrounding the smoke pipe, and An object of the present invention is to provide a ceramic smoke pipe that is easy to assemble and repair, and has durability and flexibility.

[Means for Solving the Problems] In order to solve the above problems, the smoke tube for a radiant heat exchanger tube with a mantle of the present invention described in the field of industrial application is formed as follows. That is, a sleeve is formed at one end of the pipe member, and the other end of the pipe member is loosely fitted to the other end of the other pipe member to be connected, and a ceramic material is provided on the outside of the joint using the sleeve of the smoke pipe. A cover ring is loosely fitted and extends in the axial direction of the tube member so as to overlap the small diameter section formed at the other end of the tube member, and thus covers the sleeve of the corresponding tube member at this joint. At least a portion is covered by the extending portion of the covering ring.

The connection of the tubular members is such that the two tubular members can move relative to each other to some extent in the axial direction at the connection point without separating the tubular members. An annular gap formed between the inner wall of the sleeve and the inserted tube member opens to the outside of the smoke tube through a gap extending in the axial direction of the smoke tube. Further, the cover ring fitted around the outside of the annular gap has two parts extending in the axial direction of the smoke pipe on the outer circumferential surface of the sleeve and between the pipe member fitted in the sleeve and the outer circumferential surface and guiding the gap to the outside. Forms an annular gap. Therefore, the gaps that are necessarily formed at the connection points of the pipe parts inserted with play act as a labyrinth that presents a high fluid resistance to the flow of the hot flame gas inside the smoke pipe.

The flame gas leaking through the gap of high fluid resistance is in the annular space between the mantle tube and the flue.
Flows only in the axial direction of the flue. That is, the high temperature leaked gas passes along the surface of the pipe member, that is, along the ceramic material, so that the gas does not harm the mantle tube or the smoke pipe. Furthermore, at the connection point, there is no leakage of the flame gas flow radially discharged from the outside of the flue, that is, the flame gas flow impinging on the metal mantle tube and locally overheating that part.

The tube part and the cover ring forming the flue are fitted together without any irremovable connection point between them.

Therefore, even if a damaged part occurs, the damaged part can be partially replaced without replacing the entire smoke pipe.

In order to improve the sealing effect of the connection points of the tube parts, it is advantageous if the cover rings each project axially beyond the sleeve. Furthermore, in a preferred embodiment, the cover ring is fixed to the smoke pipe in one axial direction so that it cannot fall off, thereby facilitating assembly and preventing unintentional movement of the cover ring on the smoke pipe. Obtainable. In order to obtain the above effect, an annular shoulder is formed at the end of each tube member opposite the sleeve, for example to prevent axial movement of the covering ring.

A preferred structure for the connection between the burner and the flue is such that the sleeved end of the tube member adjacent to the burner is inserted into a ceramic joint used for connection with the burner, and the cover ring adjacent to this joint. is attached to the sleeve of the tube member with some play. The covering forms a close connection between the semi-semi-fabricated connection and the smoke pipe, so that there is no back combustion (z) between the connection and the smoke pipe.
urueckbrennen) does not occur.

Since the above-mentioned connection part for the burner and the smoke tube are simply inserted, when it becomes necessary to disassemble the burner, the smoke tube can be easily pulled out without removing the smoke tube from the mantle tube. Since the cover ring has a spacer on its outer circumferential surface, it is possible to align the cover ring with respect to the burner connection in the vicinity of the connection at the same time as the flue. Similarly, it is advantageous if the cover ring is provided with a spacer on its outer periphery for aligning the smoke pipe with the mantle tube.

Since the cover ring with the spacer also defines the smoke pipe at the end opposite to the burner, the cover ring with the spacer inserted at the end of the smoke pipe has a diameter of about 180 mm.
By placing it in a rotated position, the flue can be aligned without the need for a special alignment mechanism.

The tubular member, typically formed with a wall thickness of about 5u+, is made of ceramic that can withstand a single load. The ceramic suitable for achieving the purpose of the present invention is pure silicon carbide.

[Example] Hereinafter, the present invention will be described based on an example with reference to the drawings.

A ceramic smoke pipe 3 is coaxially inserted into a cast steel mantle tube 1 having a closed end 2.

An annular space 4 is formed between the smoke pipe 3 and the mantle tube 1,
The annular space 4 is used for exhausting combustion gases. The mantle tube 1 forms part of an industrial burner (not shown). For this burner, only the connecting part 5 is shown, which has a conical part projecting coaxially into the mantle 1 and into it. This connecting part 5 is made of ceramic like the smoke pipe 3, and has a substantially cylindrical connecting part 6 that is fitted into the smoke pipe 3.

A plurality of ceramic pipe members 7 of the same shape forming the smoke pipe 3 are formed thin, one end 8 of the smoke pipe 3 is formed as a sleeve 8, and the opposite side of the sleeve 8 has an annular shape. small diameter cylinder part 9 through shoulder part 10 of
is formed. The tubular member 7 is made of pure silicon carbide, and its wall thickness is typically approximately 5 mm. However, in the drawings, the shape of the small diameter cylinder portion 9 has been reduced to approximately 0.5 to 1 m+m in order to clearly show the shape.

Sleeve 8 of tubular member 7 with smooth walls on the inside and outside
is inserted with radial play in a manner that is clear from the figure, while the end of the tube member 7a adjacent to the burner on the sleeve 8 side is inserted into the connection part 6 of the connection part 5. .

At each sleeve connection point between the pipe members 7, a ceramic covering ring 11 is loosely fitted on the outside of the smoke pipe 3. The cover ring 11 extends over the small diameter cylinder portion 9 protruding from the sleeve of the adjacent tube member 7;
It is supported between the annular shoulder 10 of one tube member 7 and the sleeve 8 of the adjacent tube member 7 so as not to shift in the axial direction. Each covering ring 11 has an extension 12 which axially at least partially covers the sleeve 8 installed therein. However, if necessary, a cover ring 11 may be provided with a portion extending beyond the sleeve 8 as shown by reference numeral 13. The cover ring 11 is provided with a portion extending beyond the sleeve 8 as shown by reference numeral 13. It has a plurality of spacers 14 that protrude and are formed integrally with the cover ring 11 and have five recesses alternately. The spacer 14 protrudes radially to the inner wall of the mantle tube 1, supports the smoke tube 3 on the inner surface of the mantle tube 1 in the radial direction, and serves to align the smoke tube 3 and the mantle tube 1 in the radial direction. By arranging the extending spacers 14 at intervals from each other, it is not possible to extremely reduce the fluid resistance to the exhaust gas flowing through the annular space 4, but it is possible to prevent the flue pipe 3 from being sufficiently out of alignment with the mantle tube 1. so that it can be maintained strongly.

When the cover ring 11 having the spacer 14 fitted to the free end of the pipe member 7 used at the end is rotated by 180 degrees, as is clear from the drawing, the smoke pipe 3 rotates while pushing the pipe member 7 at the end. , the flue 3 can be completely radially supported and centered at the free end without the need for special support or alignment elements. Also, at the outlet end of the smoke pipe 3, the end of the smoke pipe is enlarged.

At the other end of the smoke pipe 3, a ceramic connecting ring 15 is fitted into the sleeve 8 in close contact with the connecting part 6 of the connecting part 5 on the outside, and the cylindrical outer circumferential surface is provided with rib-shaped circumferences arranged at equal intervals. A spacer 16 is provided. The spacer 16 is
The smoke pipe 3 and the connecting part 5 are supported and aligned in the radial direction on the inner wall of the mantle tube 1.

As shown, only an annular gap is formed between the connection point of the tube member 7 and the connection point with the tube member 7a adjacent to the burner and close to the connecting portion 5, and the annular gap is It is communicated with an annular space 4 through an axial gap 3. The annular gaps are marked 17 and 18.
It is shown in Member 11 connecting adjacent pipe members 7
, 8, a labyrinth-like annular gap is formed between them, and this labyrinth-like annular gap allows the roaring flame gas in the smoke pipe to eject in the radial direction toward the annular space 4. to prevent

When the mantle tube 1 is deflected or its length changes, the tube members 7 are stretched relatively largely in the axial direction at their connection points, but this also prevents a tight connection between the tube members or a change in the length of the smoke pipe 3. Stability is not compromised. The play provided in the connection area between the sleeve 8 and the cover ring 11 allows the smoke pipe 3 to follow relatively large deflections of the mantle tube 1, but this also prevents unmanageable stresses from being applied to the pipe member or the cover ring 11. It is thought that it is unlikely to be caused by this.

It is unnecessary to glue or fix the individual parts forming the smoke pipe 3 with sealing cement, except when fixing the parts to each other is necessary for special use. [Effect] This invention By using this, a pipe member with a simple and smooth wall can be manufactured at a small cost, and the spacer provided on the cover ring stabilizes the connection between the smoke pipe and the mantle tube at the connection point of the pipe member. In addition, it is possible to obtain effects such as being able to easily align the smoke pipe and the mantle tube.

[Brief explanation of drawings]

The drawing is a sectional view showing a main part of the smoke tube for a radiant heat exchanger tube with a mantle according to the present invention. 3... Smoke pipe, 5... Connecting part, 7... Pipe member,
7a... Pipe member, 8... Sleeve, 9...
Small diameter cylinder part, 1o...Shoulder part, 11...Cover ring, 14...Spacer, 15...Connection ring, 16...Spacer, 18...Sleeve.

Claims (9)

[Claims] (1) A smoke tube that is incorporated into a radiant heat exchanger tube with a mantle, which includes spacers that each protrude from the outer periphery, at least one of which is made of ceramic, and which are connected to each other at their ends, and where the spacer is In a smoke tube for a radiant heat transfer tube with a mantle used in an industrial burner, which is formed to support a mantle tube surrounding the pipe member (7, 7a), a sleeve (8) is formed at one end of the pipe member (7, 7a), The other ends of the pipe members (7, 7a) must be loosely fitted to the other ends of the other pipe members to be connected, and the sleeve (
8), a ceramic cover ring (11) is loosely fitted on the outside of the joint using At least a portion of the sleeve (8) of the corresponding tube member (7, 7a) of this joint extends so as to overlap the small diameter section (a) formed at the end, and is therefore connected to said covering ring (11).
) A smoke pipe for a radiant heat exchanger pipe with a mantle, characterized in that the smoke pipe is covered by an extending portion of the mantle. (2) The radiant heat exchanger tube according to claim (1), characterized in that the cover ring (11) extends in the axial direction of the tube member so as to overlap the sleeve (8). smoking pipe. (3) According to claim (1) or (2), the covering ring (11) is attached to the smoke pipe (3) so as to substantially coaxially surround the smoke pipe. Smoke pipe for the radiant heat transfer tube described. (4) Each tube member (7, 7a) has a sleeve (8
radiant heat exchanger tube according to claim 3, characterized in that it has an annular shoulder (10) at the end opposite to the cover ring (11) that supports the covering ring (11) in the axial direction. smoke pipe. (5) A ceramic connection part (5) for the burner is inserted into the sleeved end of the tube member (7a) adjacent to the burner, and this connection is inserted into the sleeve (8) of said tube member (7a). Radiation according to any one of claims 1 to 4, characterized in that the connecting ring (15) attached to the part (5) is inserted with play. Smoke pipe for heat transfer tubes. (6) The flue for a radiant heat exchanger tube according to claim (5), characterized in that the connecting ring (15) has a spacer (16) on its outer peripheral surface. (7) The cover ring (11) has a spacer (14) on its outer peripheral surface, according to any one of claims (1) to (6). Fire pipe for radiant heat transfer tubes. (8) Covering (1) having the spacer (14)
1) is attached to the pipe member (7) disposed at the end thereof in a state of being rotated by 180 degrees. (9) The radiation transmission according to any one of claims (1) to (8), characterized in that the tube members (7, 7a) are made of pure silicon carbide. Smoke pipe for heat pipes.