JPH0247646B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application The present invention relates to a gas welding device, particularly a gas welding device or pressure welding device using oxygen-acetylene gas.

2. Prior Art In this type of gas welding equipment, objects such as a pair of reinforcing bars to be welded are joined together, and a nozzle for spouting a mixed gas of acetylene and oxygen is placed around this joint (part to be welded). There is generally known an apparatus in which a nozzle is arranged to spray the above-mentioned mixed gas onto the part to be welded.

However, this device has the following problems.

In other words, if the above bonding is insufficient and there is even a small gap, welding will occur with atmospheric oxygen penetrating this gap.
The resulting weld may take up oxygen (oxidize) and the pair of objects may not be welded at all, or the weld may be so weak that it easily breaks when stress is applied. For this reason, it is necessary to apply considerable force to the workpiece even in the early stages of welding to eliminate the gap at the joint, but it is impossible to completely eliminate the gap even if pressure is applied in this way. Yes, it is not possible to prevent the formation of an oxide film at the weld.

Another problem is that the surface of the object to be welded is usually already oxidized by oxygen in the atmosphere (this is because the surface of the object to be welded is usually already oxidized by oxygen in the atmosphere (this is because the surface of the object to be welded is often already oxidized by the oxygen in the atmosphere). (This is noticeable in some cases.) Therefore, before welding, the oxide film on the surface of the object must be sufficiently removed by polishing means such as a sander.

On the other hand, a nozzle is provided with a spout for the above-mentioned mixed gas and a spout for only acetylene gas in parallel, and the acetylene gas from the latter spout forms a reducing flame sphere for the part to be welded. Devices that attempt to prevent oxidation are conceivable. However, in this case, simply spraying acetylene gas will easily mix with the mixed gas, resulting in the same effect as spraying a mixed gas containing excess acetylene, and will not solve the problem.

3. Purpose of the Invention As a result of diligent efforts, the present inventor has developed a device that can effectively solve all of the above-mentioned problems, particularly by skillfully devising the gas blown out from the gas outlet and the outlet. We discovered this and came up with the present invention.

4. Structure of the Invention That is, the present invention provides a plurality of first nozzles that eject a mixed gas of a fuel gas and an oxidizing gas to a welding position of an object to be gas welded; and a second nozzle that is provided at a different position from the first nozzle that ejects substantially only the fuel gas, the plurality of first ejection ports that eject the mixed gas are A plurality of the second nozzles each having a second ejection port for ejecting only the fuel gas are provided in each of the first nozzles, and the first nozzles are arranged at an angle of about 180 degrees from each other. The plurality of first nozzles are arranged radially symmetrically along the circumferential direction of the welding position while facing each other at an angle, and the plurality of first jet ports are arranged symmetrically with respect to the central axis of each of the first nozzles. By being oriented in the opening direction, the mixed gas is sprayed almost evenly over the entire circumference of the welding position, and the second nozzle is oriented in the direction of opening. The outlets are formed opposite to each other toward the central axis of symmetry of the radially symmetrical arrangement of the first nozzle, and the fuel gas is configured not to substantially mix with the mixed gas at the welding position. This relates to a gas welding device characterized by:

5 Examples Hereinafter, examples in which the present invention is applied to an oxygen-acetylene gas welding device or a pressure welding device will be described in detail using the drawings.

First, the overall configuration of the gas welding apparatus according to this embodiment will be explained with reference to FIGS. 1 to 7.

This device consists of a blowpipe part 1 and a nozzle part (or burner part) 2, and an oxygen gas introduction pipe 3 and an acetylene gas introduction pipe 4 are provided at the tip of the blowpipe part 1, and each gas from these introduction pipes is are mixed with each other in the confluence pipe section 5 and guided from the blowpipe 6 to the nozzle section 2.

The acetylene gas from the inlet pipe 4 is branched in the grip part 36 of this device, one part is mixed with the oxygen gas, and the other part is led to the nozzle part 2 through another blowpipe 7. In the figure, 8 is an acetylene gas regulating valve (nut), 9 is an oxygen gas regulating valve (nut), and 10 is an oxygen acetylene mixed gas regulating valve (nut), all of which are known screw-in valves. It is configured as.
The blowpipe 6 for mixed gas is further branched into U-shaped branch pipes 11 and 12 of the nozzle section 2, respectively, and communicated with nozzles 13 and 14 and 15 and 16, which are integrated with each branch pipe. On the other hand, the blowpipe 7 containing only acetylene gas is branched into small pipes 17 and 18 in front of the nozzle part 2, and after penetrating the side walls of the branch pipes 11 and 12, respectively, they are passed between the nozzles 13 and 14 and into the nozzles 15 and 16. Nozzles 30, 31 provided between
being guided to the tip of In addition, nozzle part 2
can be removed from the blowpipe 6, 7 by loosening the nuts 38, 39, and can be replaced with a nozzle suitable for the size of the object.

Here, it is important that the nozzle section 2 is constructed as shown in FIG. First, nozzle 13-1
6 is arranged radially symmetrically in the radial direction with respect to the welded part 20 of the object 19 to be welded (for example, a reinforcing bar), and at each tip there are at least two holes along the circumferential direction of the welded part 20. Mixed gas outlet 21
and 22, 23, 24, 25, 26, 27 and 28 are formed obliquely from the nozzle central axis. The mixed gas 29 from each of these jetting ports is evenly sprayed at eight locations on the part to be welded 20, so that heating by the gas flame can be uniformly performed. In addition, when performing gas welding, each nozzle 13 to
Each nozzle is arranged such that the center of the object 19 is located at the intersection point P of the central axes of the nozzles 16 and 16, and each positional relationship is such that the perpendicular line from the center and the extension line of the blowpipe 6 intersect at right angles to each other. It is good to define. In other words, this makes it possible to ensure uniform distribution of the mixed gas during welding.

In addition to the above-mentioned nozzle arrangement, a noteworthy configuration is that the above-mentioned small tubes 17 and 18 are arranged in a separate nozzle 3 from the above-mentioned nozzles 13 to 16, facing each other at an angle of 180 degrees.
0 and 31, and are opened as acetylene spout ports 32 and 33. These spouts 32, 33 are therefore connected to the object 1.
9 can be sprayed with acetylene gas to each other in the radial direction. Note that FIG. 9 schematically shows the gas flow path in the blowpipe.

Next, a method of welding using the gas welding (or pressure welding) apparatus configured as described above will be described.

First, as shown in FIG. 10, the welded parts 20 of objects to be welded, for example, a pair of reinforcing bars 19a and 19b, are brought into contact with each other. At this time, since the part to be welded 20 is cut diagonally in order to improve the heating efficiency during welding, there is a certain gap 4 there.
0 exists. The existence of this gap 40 poses no problem for reasons explained in detail later, and there is no need to apply initial pressure. What should be noted in particular in the state before welding starts as shown in FIG.
There is no problem even if 0 is present; in fact, the welding efficiency improves, and even if an oxide film already exists on each surface (especially the surface to be welded) of the reinforcing bars 19a and 19b, it can be removed by sanding as in the conventional method. There is no need to remove it in advance.

Next, as shown in FIGS. 11A and 11B, each nozzle is set so as to surround the part to be welded (or welded part) 20 of a pair of reinforcing bars 19a, 19b, and an appropriate amount of oxygen-acetylene mixed gas 29 is injected from each nozzle. Acetylene gas 41 is spewed out. When the temperature of the welded part 20 increases due to the gas flame, the reinforcing bar 1
By pressing 9a and 19b together by, for example, hydraulic drive and welding in this state, a welded part 35 that rises uniformly around the entire circumference is created as shown in Fig. 12, and both reinforcing bars are completely connected. Can be welded. During this welding, the
As clearly shown in Figure 1B, the mixed gas 29 is sprayed almost evenly around the entire circumference of the object, and at the same time, the acetylene gas 41 is sprayed at a position different from this spraying position.
It is extremely important to spray the acetylene gas directly through the jet ports 32 and 33 of the nozzles 30 and 31, and to prevent this acetylene gas from mixing with the mixed gas 29 during spraying. In this case, the respective spraying positions of the acetylene gas 41 and the mixed gas 29 may be shifted in the axial direction of the reinforcing bars 19a, 19b. Therefore, the acetylene gas 41 fills the gap 4
There will be sufficient contact with 0 and its vicinity. Furthermore, as clearly shown in FIG. 11B, since the mixed gas 29 from each nozzle is blown in the angular relationship shown, each mixed gas flow mixes with each other after colliding with the circumferential surface of the object, creating a turbulent flow. 34 is generated, and the mixed gas flow due to this turbulence spreads along with the reducing gas in the direction along the axis of the object as shown by the dashed line in FIG. 11A. This is an effective phenomenon in shielding the part to be welded from atmospheric oxygen.

After welding is performed in this manner, the welded portion 35 is polished or the like as required to flatten the surface 37 of the product as shown in FIG. 13.

As can be understood from the above, according to the gas welding apparatus (gas pressure welding apparatus) of this embodiment, the welded part 20 between the reinforcing bars 19a and 19b is
As described above, the mixed gas 29 is evenly applied to the surfaces, and uniform heating can be performed. Furthermore, even if there is a gap between the joints of both reinforcing bars 19a and 19b, the area of the reduction flame for the part to be welded 20 will be sufficiently expanded by the jetting of acetylene gas from the jetting ports 32 and 33. Accordingly, the oxidation reaction in the welded portion 20 is inhibited, and the formation of an oxide film or oxide can be effectively prevented. This anti-oxidation effect is achieved by ejecting the acetylene gas to a position different from the ejecting position of the mixed gas, and at each ejection port 3 of the nozzles 30 and 31.
Because they are ejected from 2 and 33 in opposite directions,
It is in extremely good condition. The effect of ejecting the above acetylene gases in opposite directions is that a kind of turbulent flow occurs evenly due to the collision of the acetylene gases, which prevents localization of the gas flame. It also contributes to expanding the area of the reducing flame.

Therefore, in the above device, there is no problem even if the initial pressure is not applied during welding as in the conventional case (that is, even if the gap 40 exists), and the welding workability is improved. Moreover, even if an oxide film exists on the surface of the reinforcing steel before welding, this oxide film will be reduced during welding by the effective supply of acetylene gas 40, so it will not remain in the welded part 35. do not have. For this reason, there is no need to remove the oxide film in advance.

In the welded parts obtained using the above-mentioned apparatus, no surface properties or appearance peculiar to oxides were observed, and it was confirmed that carbon was present or adhered everywhere. This means that the acetylene-oxygen weldability is sufficient while the above-mentioned reducing atmosphere acts effectively during welding.
It was also confirmed that the welded portion had sufficient strength, and there were no problems in tensile tests and bending tests.

Note that the positions of the acetylene gas jet ports 32 and 33 are very important from the above point, but according to this embodiment, the positions of the nozzles 32 and 33 are different from the nozzles 13 to 16.
Since it is formed independently at 0 and 31, it is easy to achieve positional accuracy.

In other words, by bending the nozzles 30 and 31, the position where the acetylene gas hits the welding part can be adjusted to some extent.

Furthermore, since this welding device achieves a uniform heating effect, it is not necessary to perform operations such as rotating the object to equalize the heating area, which also greatly contributes to improving work efficiency. There is.

FIGS. 14 and 15 show modifications of the nozzle structure described above.

In this example, the small tube 1 for the acetylene gas mentioned above
7 and 18 are led along the outer surface of each branch pipe 11 and 12 of the nozzle section 2 to the tips of the nozzles 30 and 31. Even with this configuration, 32 at the tip of the nozzle,
By orienting each of the 33 jet ports toward the part to be welded, it is possible to obtain the same oxidation prevention effect as in the first embodiment described above. Also, each small tube 17, 18
Since it is integrated with the nozzle, the object can be easily observed during welding and does not interfere with the work.

FIG. 16 shows yet another welding device, which differs from the above-mentioned example in that the grip portion 36 is provided in the same direction as the blowpipe 6 (that is, it is not bent). . This linear welding device may be appropriately selected and used depending on the place where it is used.

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, the number of each nozzle mentioned above, the number of mixed gas and acetylene gas jetting ports, and the positions can be variously changed. Further, the type of gas used is not limited to those described above as long as it can be used for gas welding or pressure welding. Further, the object to which the present invention is applied may be other than the above-mentioned longitudinal materials such as reinforcing bars, and the ejection method of each gas and the structure of the nozzle can be changed as appropriate depending on the type of object. .

6. Effects of the Invention According to the gas welding device of the present invention, the gas mainly composed of fuel gas is sprayed at a position different from the mixed gas of fuel gas and oxidizing gas so as not to mix with the mixed gas. Therefore, this gas can sufficiently form a reducing flame sphere in the part to be welded, effectively blocking the influence of oxygen, and completely preventing the formation of an oxide film or oxides that may occur during welding. . In particular, the first jet ports for the mixed gas are symmetrically positioned with respect to the center axis of each nozzle and are oriented in the direction of opening each other, so the mixed gas is jetted out in a spreading manner and is blown diagonally toward the welding location. The fuel gas is reflected and collides with each other, staying around the welding position and burning, creating a flame hot enough for welding.On the other hand, the fuel gas ejected from the second nozzle hits the welding position. It strikes at a nearly right angle and then spreads out to form an independent reducing flame sphere, which prevents it from mixing with the gas mixture. Therefore, a reducing flame is formed so as to surround the position to be welded, which is further surrounded by a high-temperature flame due to the combustion of the above-mentioned mixed gas. As a result, the position to be welded does not come into direct contact with the oxidizing flame caused by the combustion of the mixed gas, but is surrounded by the reducing flame of the fuel gas, which not only prevents oxidation, but also prevents oxidation from occurring due to the reducing flame of the fuel gas. The soot produced by complete combustion will have a reducing effect. As a result, not only can a welded part with sufficient strength be formed, but even if there is a gap between the objects during welding, this gap will be filled with the reducing flame, so no problems will occur. Therefore, there is no need to apply initial pressure to the object during welding, and work efficiency is greatly improved. In addition, even if an oxide film already exists on the surface of the object before welding, this oxide film is reduced and disappears by the reducing flame caused by the fuel gas, so the work to remove the oxide film can be omitted. This also contributes to improved welding workability and yield.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a plan view of the gas welding device, Fig. 2 is a back view of the same device, Fig. 3 is a front view of the same device, and Fig. 4 is a plan view of the same device. 5 is a right side view of the device, FIG. 6 is a left side view of the device, FIG. 7 is a perspective view of the device,
Figure 8 is a partial sectional view of the nozzle part (burner part),
Figure 9 is a schematic flow path diagram of gas in the blowpipe; Figure 10;
11A, 11B, 12, and 13 are diagrams showing each stage of welding work, and FIG. 14 is a plan view of a part of the nozzle part (burner part) according to another example,
FIG. 15 is a partial sectional view of the nozzle portion, and FIG. 16 is a front view of a gas welding apparatus according to still another example. In addition, in the symbols shown in the drawings, 1... blowpipe part, 2... nozzle part (burner part), 6, 7...
...Blowpipe, 13, 14, 15, 16...Mixed gas
Nozzle, 17, 18... small tube, 19... object,
20... Portion to be welded, 21-28... Mixed gas outlet, 29... Mixed gas, 30, 31... Fuel gas nozzle, 32, 33... Fuel gas outlet, 3
4...Turbulent gas, 35...Welded portion, 40...Gap.

Claims (1)

[Claims] 1. A plurality of first nozzles that eject a mixed gas of fuel gas and oxidizing gas to the welding position of the object to be gas welded; provided at a different position from these first nozzles, and a second nozzle that ejects substantially only the fuel gas, wherein each of the first nozzles is provided with a plurality of first ejection ports that eject the mixed gas, A plurality of the second nozzles each having a second ejection port for ejecting only the fuel gas are provided, and the first nozzles face each other at an angle of approximately 180 degrees. The plurality of first nozzles are arranged radially symmetrically along the circumferential direction of the position, and the plurality of first jet ports are oriented in a direction in which they open to each other in a symmetrical positional relationship with respect to the central axis of each of the first nozzles. Therefore, the mixed gas is sprayed almost uniformly over the entire circumference of the position to be welded, and in the second nozzle, the second ejection port is radially aligned with the first nozzle. The gas welding apparatus is formed to face each other toward a central axis of symmetry in a symmetrical arrangement, and is configured such that the fuel gas does not substantially mix with the mixed gas at the welding position. .