JPH0645146Y2 - Pilot burner - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a pilot burner having a structure capable of absorbing a length error in mounting a frame rod.

[Conventional technology]

In a heating furnace equipped with a large number of burners, such as a continuous annealing furnace for metallic steel strips, it is the most important point for safe operation that all the burners burn stably. If one of the burners in it burns out for some reason, the operator must take action to immediately close the valve of that burner. However, visually confirming the combustion state of many burners will cause an excessive load on the operator and cause an accident.
That is, there is a great need for a means for detecting whether it is "burning" or "misfiring", and various means have been proposed ("Industrial heating", Vol. 24, No. 4, 1987/7, Japan Industrial Reactor Association, P.84, frame rod, optical sensor).

FIG. 4 is an example of a pilot burner that meets the above-mentioned need. In this pilot burner 1, the fuel supplied from the fuel supply port 4 is ejected from the nozzle tip 2 and the flame 6 is generated in the flame holding cylinder 3. It is formed. On the other hand, the frame rod 5
Is a frame rod insertion opening 7 provided on the side surface of the flame holding cylinder 3.
It is further inserted inside the flame holding cylinder 3 and fixed by the insulating support 8.

Here, when a predetermined voltage is applied between the frame rod 5 and the pilot burner 1 from the constant voltage generator 9, the flame 6
The ions inside move between the tip of the frame rod 5 and the flame holding cylinder 3 or the nozzle tip 2 to flow a weak current. By detecting this weak current with the current detector 10, the presence or absence of the flame 6 is detected. Can be detected. Further, when the frame rod is arranged along the pilot burner 1 as shown in FIG. 4, in order to fix the frame rod 5, this is covered with an insulator cylinder 11, and further the fixing metal fitting 12 covers the insulator cylinder 11. It is designed to be fixed.

[Problems to be solved by the device]

By the way, heretofore, this frame rod has been formed as an integral body and has a length of 1000 mm or more depending on the length of the pilot burner. However, in such a case, the following problems have occurred. That is, (1) If the manufacturing accuracy and processing accuracy of the frame rod and pilot burner are low, the tip position of the frame rod does not match the frame rod insertion port,
The tip of the rod cannot be inserted into the flame holder. (2) The pilot burner and the frame rod are exposed to a high temperature atmosphere at the installation position, but since the fuel at room temperature is generally flowing in the pilot burner, the temperature of the pilot burner body is low and the thermal expansion is small, Since the frame rod becomes hot, a difference in thermal expansion occurs between the pilot burner and the frame rod, which causes the frame rod to deform,
The insulator or the insulating support may be damaged and the frame rod may short-circuit with the flame holding cylinder or the fixing bracket, and the flame situation cannot be detected.

The present invention has been made in view of the above problems, and an object thereof is to solve the above problems by dividing the frame rod without forming it as an integral body.

[Means for Solving the Problems]

This invention is a pilot burner in which a flame rod is inserted into the flame holding cylinder from the side of the flame holding cylinder and the flame is also monitored by detecting the ion current in the flame. This is a pilot burner provided with an adjusting device that divides the frame rods arranged along the line, electrically connects the divided frame rods to each other, and adjusts the length of the entire frame rod.

[Action]

Since this invention has the above-mentioned configuration, even when this pilot burner is exposed to a high temperature atmosphere,
The divided frame rods expand and contract due to heat in an electrically connected state, and the expansion and contraction are absorbed in the adjusting device, and the relative length of the frame rod as a whole to the pilot burner main body does not change. Therefore, stress due to expansion and contraction is not applied to the engaging member with the frame rod provided in the pilot burner, so that the engaging member is not damaged.

〔Example〕

The present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of the present invention. However, the same parts as those of the conventional example are denoted by the same reference numerals, and duplicated description will be omitted. Further, FIG. 4, which is an explanatory view of the conventional example, has the same configuration as that of the present embodiment except for the intermediate main parts omitted.

FIG. 1 is a schematic side view of the embodiment, and 13 is an adjusting device for adjusting the length of the frame rod 5. FIG. 2 is a detailed view of the adjusting device 13, and 5A and 5B are the same ones which are obtained by dividing the frame rod which is one in the conventional example. 13a is a metal pipe, which is fitted with the frame rods 5A and 5B with high precision, and is welded to one frame rod, for example, 5A so as to be integrated with the other frame rod 5B. ing. Further, since this adjusting device 13 receives heat in a high temperature atmosphere, if the metal pipe 13a and the frame rods 5A and 5B have different coefficients of thermal expansion, a gap is created between them and the electrical connection becomes unstable, or It is desirable that they are made of the same material because they cannot slide on each other. That is, since both are made of the same material, the metal pipe integrated with the frame rod 5A
Expansion and contraction due to heat between 13a and the frame rod 5B is absorbed by the sliding of the frame rod 5B in the metal pipe 13a, and the expansion and contraction stress does not affect other parts, and in FIG. The relative length between the entire rod length and the main body of the pilot burner 1 is kept unchanged. Further, all assembling dimensional errors caused by the manufacturing processing accuracy of each component are also absorbed by the sliding engagement between the metal pipe 13a and the frame rod 5B.

With the above configuration, the function of detecting the weak current due to the ion current in the flame 6 and detecting the presence or absence of the flame is as described in the conventional example, but the accuracy of the function is the same as that of the conventional example. It's totally different and almost complete.

FIG. 3 shows another embodiment.

In the figure, the frame rods 5A and 5B are accommodated in the pipe of the insulator 11 in a free state while being electrically connected by the metal wire 14.

In order to absorb the expansion and contraction of the frame rods 5A and 5B, the metal wire 14 is formed in a loop shape at the center portion 14a, and both ends are terminal plates 15
Is connected to the frame rods 5A and 5B by a nut 16 via.

Therefore, also in this embodiment, the total length of the frame rod and the relative length between the main body of the pilot burner 1 are kept the same, and any assembly dimensional error due to the machining accuracy of each component is also absorbed by the loop-shaped metal wire 14.

The present invention is not limited to the device according to the above-mentioned embodiment as long as it has a function of electrically connecting the divided frame rods and absorbing expansion and contraction of the frame rod.

Next, examples will be described.

The embodiment shown in FIG. 3 and the conventional example shown in FIG. 4 were adopted as the radiant tube burner in the continuous annealing furnace for metal steel strips. This continuous annealing furnace has 180 radiant tubes, and the conventional example has the tip position of the frame rod deviated from a predetermined position as described in the problem of the problem to be solved by the invention. In addition, there is a problem that a flame current is not detected due to a short circuit due to damage to the insulator that fixes the frame rod.

On the other hand, although the pilot burner according to the present invention was used continuously for 3 × 10 ⁴ hours, there was no short circuit and stable flame detection was performed.

[Effects of the Invention] As described above, according to the present invention, the tip of the frame rod can be aligned with the rod insertion opening even if the machining accuracy of the pilot burner is low, and the relative length between the frame rod and the pilot burner body is long. Since the same length can be maintained, damage to the frame rod holding insulator and failure such as short circuit of detection current can be prevented, the life of the pilot burner can be remarkably extended, the operator's load can be remarkably reduced, and safe operation can be performed. Etc., a great effect can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic side view of one embodiment of the present invention, FIG. 2 is a partially enlarged sectional view of this embodiment, FIG. 3 is a sectional view of essential parts of another embodiment, and FIG. It is a side view with a part fracture. 1 …… Pilot burner, 3 …… Flame holding cylinder, 5,5A, 5B ……
Frame rod.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Fujita, 1 Kawasaki-cho, Chiba, Chiba Prefecture, Chiba Steel Works Co., Ltd. (72) Kuniaki Sato, 1 Kawasaki-cho, Chiba, Chiba Iron Works, Chiba Steel In-house (72) Inventor Hiroyuki Nakamura 2-31 Shirute, Tsurumi-ku, Yokohama-shi, Kanagawa Japan Furnace Industry Co., Ltd. (56) References: Kaihei 2-45339 (JP, U) JP, Y1)

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A pilot burner for inserting a flame rod into the flame holding cylinder from the side of the flame holding cylinder and detecting the ion current in the flame to monitor the flame. The pilot burner is characterized in that the frame rods arranged along the above are divided, and the divided frame rods are electrically connected to each other to be integrated and an adjusting device for adjusting the length of the entire frame rod is provided. .