JP2000345312A - Continuous thermal spraying method for outer peripheral faces of boiler tubes of panel-form and thermal spraying device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous thermal spraying method for the outer peripheral faces of boiler tubes of a panel form and a thermal spraying device therefor. SOLUTION: In order to continuously carry out a thermal spraying on boiler tubes which are connected and assembled in the form of a panel, the thermal spraying is continuously carried out on the outer peripheral faces of the tubes by passing the boiler tubes 5 through the center of a ring-formed gas supply pipe by using ring-formed thermal spraying device composed of a ring-formed gas supplying pipe 1 having plural thermal spraying nozzles 2 directed to the center of the ring and nozzles which thermally spray on the outer peripheral faces of the boiler tubes 5 and connected with supply tubes 3 which supply thermal spraying powder to the each nozzle. Thus, a high production efficiency is realized and the durability of a product is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal spraying method for performing thermal spraying on the outer peripheral surface of a boiler tube for various types of heat exchange equipment such as a boiler for thermal power generation, which is assembled into a panel by welding, and a thermal spraying apparatus used therefor.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, there has been no suitable apparatus for spraying the outer peripheral surface of a small-diameter pipe welding portion such as a boiler tube assembled by welding. However, a thermal spraying process using a torch has been adopted.

[0003]

However, manual spraying is inefficient, and the thickness and quality of the sprayed coating are not stable, and there is a problem in terms of hygiene. The present invention solves the above-mentioned conventional problems, and aims to improve the working environment by reducing the amount of work in a dust working environment, improve work efficiency by automating spraying, save labor, improve the quality of sprayed coating, and stabilize. It is an object of the present invention to provide a thermal spraying method that can be performed and a thermal spraying apparatus used for the method.

[0004]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have made intensive studies and as a result, have found that a ring-shaped thermal spraying device which is passed through one end of a boiler tube assembled by welding is used. Knowing that it is effective,
The present invention has been completed.

The present invention has been made based on the above findings,
To continuously spray the assembled boiler tubes joined in a panel shape, a ring-shaped gas supply pipe with multiple spray nozzles facing the center and a supply pipe that supplies spray powder to each nozzle part are connected For a ring-shaped thermal spraying device comprising a nozzle for spraying the outer peripheral surface of the boiler tube, the spraying is continuously performed on the outer peripheral surface of the tube while passing the boiler tube through the center of the ring-shaped gas supply pipe. The gist of the present invention is a method for continuously spraying the outer peripheral surface of a long boiler tube which is formed into a panel.

In order to use the present invention for carrying out the above-mentioned spraying method, a ring-shaped gas supply pipe having a plurality of spray nozzles directed to the center and a supply pipe for supplying a spray powder to each nozzle portion are provided. The invention is characterized in that the plurality of thermal spray nozzles are connected to form a group of nozzles for forming a thermal spray coating on the outer peripheral surface of the boiler tube, and the gist is a panel-shaped continuous boiler tube outer peripheral surface continuous thermal spraying device. It is.

The ring-shaped gas supply pipe for mounting the spray nozzle is a spray fuel gas supply pipe, and a spray powder distributor for supplying spray powder is provided inside the base of the spray nozzle. ) Is provided with a thermal spraying powder distributor for supplying thermal spraying powder, a ring-shaped gas supply pipe having an opening through which a long boiler tube can pass, and swinging in the circumferential direction of the ring A ring-shaped gas supply pipe with a mechanism to perform, and a ring-shaped sprayed fuel gas supply pipe,
The gist of the present invention is that a guide for supporting the thermal spray head and for centering the thermal spray head on the central axis of the boiler tube is also provided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of the present invention will be described with reference to the drawings. FIG. 2 shows a state in which the panel-shaped continuous boiler tube outer peripheral surface continuous spraying device of the present invention is attached to a boiler tube. A circular sprayed fuel supply pipe 1 for propylene, oxygen, or the like has a plurality of spray nozzles. 2, 2, 2
Are fixedly provided toward the boiler tube 5 located on the central axis, and fuel gas is supplied to these nozzles from the sprayed fuel supply pipe 1.

In many cases, the thermal spray nozzle blows out fuel gas from the center and blows out compressed air for combustion so as to enclose the fuel gas. The feed compressed air can prevent overheating of the thermal spray nozzle. Further, in a large-diameter boiler tube thermal spray device, safety can be ensured by adopting a structure in which a thermal spray fuel supply pipe and a thermal spray nozzle are water-cooled with cooling water.

The thermal spray powder is supplied from a powder supply pipe 3 to the thermal spray nozzle base by a carrier gas via a distributor (not shown). Depending on the structure of the spray nozzle, as shown in FIG. 3, the carrier gas is supplied directly into the spray flame (flame).

In order to uniformly spray the entire circumference of the boiler tube 5, it is necessary to provide a plurality of spray nozzles, and in particular, at least four or more spray nozzles at substantially equal intervals.
Is desirably provided. Further, by providing a mechanism that swings in the circumferential direction of the sprayed fuel supply pipe 1 as necessary, the spraying can be performed more uniformly.

The sprayed fuel is supplied from the main gas supply pipe 4 to the circular sprayed fuel supply pipe 1. FIG. 3 shows a circular sprayed fuel supply pipe 1 in which an opening through which a boiler tube can be passed is formed. The opening is opened and closed like scissors.

Furthermore, a jig for holding the boiler tube 5 at the center of the circular sprayed fuel supply pipe 1 and a guide for facilitating the running of the spraying apparatus can be attached.

[0014]

EXAMPLES The present invention will be described specifically with reference to Examples.
This does not limit the invention. Example 1 As shown in FIG.
(Material: STBA-22, dimensions: diameter 40 mmφ, curved portion radius of curvature 60 Rmm, length of linear portion 3000 mm) are fixed to a jig and reciprocated through one end of the boiler tube to the thermal spraying apparatus of FIG. A uniform thermal spray coating was formed on the entire circumference.

The spray nozzles used were manufactured by Meteco Co., and four nozzles were arranged at equal intervals in a ring-shaped gas supply pipe having an inner diameter of 150 mm. The spraying conditions were as follows: LPG (propylene 95 wt% + propane 5 wt%) 0.5 liter / sec as fuel gas;
Oxygen 1.5 liter / sec, Ni-based self-fluxing alloy as thermal spray powder (C: 1.7, Si: 3.5, Mn: t in wt%)
r, Cr: 12.3, Mo: 1.7, Fe: 3.0,
B: 2.4, Ni: bal. ) Was supplied at a rate of 50 g / sec, and the spraying nozzle moving speed was 0.5 m / min. The thickness of the formed sprayed coating was 0.2 mm on average, and the variation in coating thickness was ± 0.03 mm. This was repeated 10 times to form a sprayed coating having a coating thickness of 2 ± 0.3 mm.

In the conventional thermal spraying operation using a manual device, a sprayed coating is formed only for 1/30 minutes, and the uniformity of the sprayed coating cannot be obtained.
Thermal spraying can be performed at a rate of 0 minutes, a three-fold improvement in efficiency, a uniform thermal spray coating is formed, and the life of the boiler tube has been greatly improved as compared with conventional products. Further, in this thermal spraying apparatus, since thermal spraying is simultaneously performed from the entire peripheral surface of the boiler tube 1, distortion due to thermal expansion is prevented, and the quality of the thermal spray coating is further improved.

Embodiment 2 Using a thermal spraying device that can be opened and closed like scissors as shown in FIG.
The same spraying operation as in Example 1 was performed. Compared with the first embodiment, there is the convenience that a thermal spraying device can be installed at an arbitrary position of the boiler tube to perform thermal spraying.

[0018]

Since the present invention is constructed as described above, it is possible to efficiently perform thermal spraying even on a paneled boiler tube, and this has not been achieved by conventional thermal spraying means. Work environment improvement, labor saving,
The excellent effect that it can greatly contribute to the improvement of the efficiency, the quality and the product life is exhibited, and it is extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a panelized boiler tube to which the present invention is applied.

FIG. 2 is a schematic view of an embodiment of the thermal spraying apparatus of the present invention.

FIG. 3 is a schematic view of another embodiment of the thermal spraying apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circular thermal spray fuel supply pipe 2 Thermal spray nozzle 3 Powder supply pipe 4 Main gas supply pipe 5 Boiler tube 6 Grasping part

Continuation of front page (72) Inventor Eiji Seki 1-3-8 Yaesu, Chuo-ku, Tokyo F-term in Nippon Steel Hard Co., Ltd. 4F033 AA01 BA01 BA05 DA01 EA01 JA08 LA12 NA01 4K031 AA01 AA04 AA08 AB08 DA01 EA01

Claims (8)

[Claims] 1. A ring-shaped gas supply pipe having a plurality of spray nozzles directed toward the center and a spray powder supplied to each nozzle portion for continuously spraying the assembled boiler tubes joined in a panel shape. To a ring-shaped thermal spraying device consisting of a nozzle for spraying the outer peripheral surface of the boiler tube to which the supply pipe to be connected is connected, spraying is continuously performed on the outer peripheral surface of the tube while passing the boiler tube through the center of the ring-shaped gas supply pipe. A continuous spraying method for the outer peripheral surface of a panel-shaped long boiler tube, which is performed. 2. A ring-shaped gas supply pipe having a plurality of spray nozzles directed toward a center, and a supply pipe for supplying a spray powder to each nozzle portion, wherein the plurality of spray nozzles are boiler tubes. A continuous spraying apparatus for a peripheral surface of a long boiler tube, which is a panel, comprising a group of nozzles for forming a thermal spray coating on an outer peripheral surface. 3. The panel according to claim 2, wherein the ring-shaped gas supply pipe for mounting the spray nozzle is a spray fuel gas supply pipe, and a spray powder distributor for supplying the spray powder is provided inside the spray nozzle base. Continuous boiler tube outer peripheral surface continuous spraying equipment. 4. The continuous thermal spraying apparatus according to claim 2, further comprising a thermal spray powder distributor for supplying thermal spray powder into the thermal spray flame (flame). 5. The continuous thermal spraying apparatus according to claim 2, wherein the ring-shaped gas supply pipe is formed with an opening through which the long boiler tube can pass. 6. The continuous thermal spraying apparatus according to claim 5, wherein the ring-shaped gas supply pipe is capable of changing the degree of opening of an opening through which the long boiler tube can pass. 7. The continuous thermal spraying device according to claim 2, wherein the continuous gas spraying device comprises a ring-shaped gas supply pipe provided with a mechanism for swinging in a circumferential direction of the ring. 8. The panel according to claim 2, wherein a guide for supporting the spraying head and for centering the spraying head on the central axis of the boiler tube is attached to the ring-shaped sprayed fuel gas supply pipe. Continuous boiler tube outer peripheral surface continuous spraying equipment.