JPS6358894B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This description relates to a method suitable for heating elongated cylindrical structures.

In welding and assembling high-strength steel, it is necessary to preheat the welded part or heat treat it after welding, especially when the plate is thick. It is good if the heating part can be heated from the outer periphery, but uniform heating is difficult when a long cylindrical body must be heated from the inside. In such cases, heating has conventionally been carried out by inserting a long and narrow hot air supply pipe having a number of hot air blowing holes on the side surface. In this case, in a tubular tube with both ends open, the hot air dissipates from both openings, and the vicinity of the hot air outlet tends to be locally heated, making it difficult to uniformly heat the entire tube. Furthermore, even heating with a high velocity burner was difficult to achieve uniform heating. The same was true for the cylindrical body with one end closed. There is also a method of using a high velocity burner and hot air distribution pipe together, but this creates a difference in hot air pressure within the cylinder, resulting in a temperature difference between the open side and the closed side.

The purpose of this invention is to uniformly heat such a cylindrical structure, and in order to adjust the pressure difference of the hot air blown in when one end is closed, an exhaust control valve is provided on the closed side. This is a characteristic feature.

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

In FIGS. 1 and 2, 1 is a tubular body with one end sealed, and a hot air distribution pipe 2 is inserted from the other end. Hot air is supplied to the hot air distribution pipe from the high velocity burner 3 via a distribution branch 4. 5
is the air volume control valve. As shown in FIG. 2, the hot air distribution pipe 2 has a number of hot air blowing holes 6 on its side.
is provided, and the hot air supplied into the pipe is ejected from this hot air ejection hole 6. The hot air supplied into the tube is discharged from the opening at the other end. 7 is a jig for holding the hot air distribution pipe. Reference numeral 8 is an exhaust control valve according to the present invention, which is used to release the pressure difference between the hot air and the hot air that is generated in the pipe due to the amount of hot air that is supplied into the pipe and the amount of hot air that is discharged from the opening side. It is. With this structure, the pressure difference inside the pipe can be easily adjusted, and as a result, it is possible to easily adjust the pressure difference inside the pipe, and as a result, it is possible to easily adjust the pressure difference in the pipe, and as a result, it is possible to easily adjust the pressure difference in the pipe. Uniform heating can be achieved much more easily than in the conventional case.

In addition, in the example, heating of a cylindrical structure with one end sealed in advance was explained, but a pipe-shaped structure with both ends open can be similarly closed by closing it with a closing body equipped with a separate exhaust control valve. can be heated evenly.

Furthermore, as shown in FIG. 2, the effect of the exhaust control valve is more pronounced when it is attached to the lower part of the closing portion 9 than when it is attached to the upper part. Total length 6000mm Inner diameter 600
A high-strength steel cylindrical body sealed at one end with a wall thickness of 50 mm and a wall thickness of 50 mm was heated using a high velocity burner. The hot air distribution pipe used was a steel pipe with a length of 6,500 mm, an inner diameter of 250 mm, and a wall thickness of 7 mm, with a hot air outlet of 300 mm on the side.
There are 40 locations in Pituchi. The diameter of the hot air outlet was 20 mm upward and 40 mm downward, and the diameter of the inner part of the tube, that is, on the blocked side, was 25 mm upward and 45 mm downward. An exhaust control valve with an inner diameter of 105 mm was attached to the blocked part. When this was heated for comparison with no exhaust control valve installed and all other conditions being the same, the temperature difference across the entire pipe using the method of the present invention was ±10°C, whereas in the comparative test In the tests conducted, the temperature on the closed side was 70°C lower than on the open side.

In this example, a long tubular body is shown, but if hot air is blown from one place and discharged from ten places, such as a cylindrical container, exhaust control valves may be installed at the required places. Therefore, uniform heating can be similarly achieved by adjusting the pressure difference. Moreover, if the outer periphery of the object to be heated can be covered with a heat insulating material such as ceramic fiber, the efficiency will be further improved.

According to the method of this invention, even long objects can be heated easily and uniformly.As a result, it is possible to control the combustion and temperature of the high velocity burner, and the high heat transfer properties of the high-velocity hot air generated generates energy. This allows for highly efficient heating.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional front view. 1... Tubular body, 2... Hot air distribution pipe, 3... High velocity burner, 4... Distribution branch, 5... Air volume control valve, 6
...Hot air blowout hole, 7...Jig, 8...Exhaust control valve, 9...
Occlusion.

Claims (1)

[Claims] 1 Attach an exhaust control valve to the closed end of the cylindrical structure, insert a hot air distribution pipe with multiple holes on the side from the opening at the other end, and supply high-speed hot air from the hot air distribution pipe into the cylindrical structure. A method for heating a cylindrical structure, characterized by: