JPS5931431B2 - Welding equipment for pipes and tube sheets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves inserting a rod-shaped copying jig equipped with a welding torch and also serving as a cooling metal into a pipe inserted into a tube insertion hole of a tube plate, and rotating the copying jig. The present invention relates to a welding device for welding the tube and the tube sheet.

Conventionally, when welding a heat exchanger tube and a tube sheet of a multi-tube heat exchanger, for example, as shown in FIG. 1 or FIG. 2, the heat exchanger tube 2 is inserted into the heat exchanger tube insertion hole of the tube sheet 1, and then Inside this heat exchanger tube 2,
Guide rod 3 having a positioning flange portion 3a (Fig. 1)
, or a guide rod 4 (FIG. 2) having a flange portion 4a that functions as a positioning member and a member for forming the shielding gas filled chamber 4b is inserted, and plasma is applied to the guide rods 3 and 4 outside the heat exchanger tube 2. A welding torch 5 such as a welding torch or a tungsten inert gas arc welding torch is fixed, and the guide rods 3 and 4 are connected to the welding torch 5 manually or by motor drive.
are rotated at the same time to weld the heat exchanger tube 2 and tube sheet 1.

However, in the conventional welding method performed in this way, in order to make the rotation of the guide rods 3 and 4 smooth, it is necessary to
The fit between the heat exchanger tube 2 and the heat exchanger tube 2 needs to be a so-called clearance fit, which makes it difficult to make the welding torch 5 rotate in a perfect circle.

Particularly when welding is carried out manually, the movement tends to be elliptical and the bead shape tends to lack uniformity. Titanium heat exchanger tubes, which have been increasingly used in recent years due to their excellent corrosion resistance, have inferior thermal conductivity compared to copper alloy materials that have been widely used in the past, and have a low thermal conductivity as heat exchanger tubes. In order to equalize the thickness, it has become necessary to make the thickness thinner.

When welding such thin-walled heat exchanger tubes, we have to use a small current welding method to prevent burn-through, but in this case, the arc flow is very thin, so the welding torch moves in an elliptical direction. If this was done, even a slight misalignment could cause heat exchanger tubes to burn through or leave unwelded parts. Additionally, since the guide rod rotates while contacting the inner surface of the heat transfer tube, if an uneven load from the welding equipment is applied to the guide rod, contact scratches in the circumferential direction may occur on the inner surface of the heat transfer tube. This was a problem that could not be ignored because it was a thin-walled tube. Furthermore, no welding apparatus has been proposed in the past that has a simple structure that avoids the above-mentioned disadvantages and at the same time has means for good axial positioning of the welding torch with respect to the welding part. An object of the present invention is to eliminate the above-mentioned drawbacks of conventional devices, and to allow the welding torch to follow the inner surface of the heat transfer tube in a perfect circle without causing scratches on the inner surface of the heat transfer tube due to the rotation of the guide rod.
Moreover, it is an object of the present invention to provide a welding device that also enables positioning in the axial direction.

According to the present invention, a pipe inner diameter copying jig inserted into the pipe is fixed in the pipe by expanding in the radial direction, a rotary sleeve is rotatably attached to this copying jig, and the rotary sleeve is This is accomplished by securing the welding torch to the weld and forming a flange on the rotating sleeve that provides axial positioning of the welding torch relative to the weld and provides a passage for shielding gas to the weld. next,
The present invention will be explained in more detail with reference to the drawings.

3 to 6 show an embodiment of the present invention.

In short, this device is a device for welding a tube sheet 1 and a tube 2, one end of which is inserted into a tube insertion hole of the tube sheet, using a welding torch 5 at the tip of the tube 2. A hollow sleeve-shaped guide rod 6 having an outer diameter smaller than its inner diameter is inserted into the tube 2 . A spindle 7 having a tapered tip and movable in the axial direction is inserted into the guide rod 6 . Correspondingly, the tip of the guide rod 6 is provided with at least three window holes approximately equally spaced in the circumferential direction, each having a length longer than the thickness of the tube sheet 1. A stator 9 is provided between 7 and the inner surface of the tube 2, which has a stator compression ring 8 arranged on its outer circumferential surface, which abuts the tube 2. A rotary sleeve 10 is further rotatably mounted on the guide rod 6 at the rear of the stator 9.

The rotary sleeve 10 has a distal end 10a slightly protruding into the distal end of the tube 2, a flange 10b formed immediately behind the distal end 10a, and a large number of heat radiation fins 10c formed at appropriate positions. The front surface of the flange portion 10b, that is, the surface facing the end surface of the tube sheet 1 or, in some cases, the end surface of the tube 2, is connected to the welding torch 5, that is, the rotating sleeve 1 for the welding portion.
Used for axial positioning of 0. Furthermore, a portion of the flange portion 10b facing the weld between the end surface of the tube 2 and the tube plate 1 is provided with a material that prevents the material of the rotating sleeve 10 from being melted and mixed into the seal weld, and allows the weld bead to escape. ,
In addition, in order to form a shield gas passage, a corresponding recess 10d is formed in advance. The welding torch 5 is attached to the rotating sleeve 10 via an attachment 11. The circumferential position of the welding torch 5 can be adjusted using an attachment 11, and the inclination angle can be finely adjusted using a spring 12 and a screw 13. Electrode 5a of welding torch 5
A notch 10e is provided in the portion of the flange portion 10b where the flange portion 10b is located to expose the welded portion between the tube sheet 1 and the tube 2 and to form a passage for shielding gas. The rotating sleeve 10 and the welding torch 5 attached thereto are driven by a motor 14 to reduce gears 16 and 1 disposed in a gearbox 15.
Rotationally driven via 7. Gearbox 15 is fixed on guide rod 6. In order to move the spindle 7 in the axial direction, an operating mechanism 19 is provided which converts the rotational movement of the handle 18 into an axial movement. Now, in this device, by pushing the spindle 7 and utilizing its taper, the compression ring 8 on the stator 9 is brought into close contact with the inner surface of the wide heating tube 2 using the wedge principle, and this stator 9 is used to improve the roundness. At the same time, the flange portion 10b is brought into contact with the tube plate 1 to perform axial positioning, and the rotary sleeve 10, which is coaxial with the flange portion 10b, is rotated by a motor drive, thereby making the welding torch 5 a perfect circle. The tube 2 and the tube sheet 1 are welded together at the end surface of the tube 2 while moving. As can be seen from the above, members 6 to 9 constitute the pipe inner diameter copying jig according to the present invention. As described above, according to the present invention, it is easy to position the welding torch in the axial direction, and the welding torch moves in a perfect circle following the inner surface of the tube without causing scratches on the inner surface of the tube due to rotation of the guide rod. It is possible to provide a welding device capable of performing the following steps.

When welding a tube and a tube plate using the welding device of the present invention, as long as the inner diameter of the tube is the same, once the radius of rotation of the welding torch is set, continuous work can be easily performed without repeating the setting work. In addition, since the welding torch moves in a perfect circle, even if the wall thickness of the pipe is thin, the operator can proceed with the work while checking whether the electrode position is out of line with the welding line, and there is no hassle. Therefore, a significant improvement in work efficiency can be expected, and even an unskilled welder can perform good welding with stable quality.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional views of the main parts of a conventional device, FIG. 3 is a longitudinal sectional view of the main parts of an embodiment of the present invention, and FIG. 4 is an enlarged view of the part indicated by the reference numeral in Fig. 3. Figure 5 is V- of Figure 3.
FIG. 6, which is an enlarged cross-sectional view taken along the line, is an overall layout diagram of the device of the present invention. 1...Tube plate, 2...Tube, 5...
・Welding torch, 6... Sleeve-shaped guide rod, 7.
... Spindle, 8 ... Stator compression ring, 9 ... Stator, 10 ... Rotating sleeve, 10b ... Flange section.

Claims (1)

[Claims] 1. A rod-shaped tube inner diameter copying jig inserted into a tube inserted into a tube insertion hole in a tube sheet and a tube inner diameter copying jig inserted into said tube are enlarged in the radial direction and tightly fixed in said tube insertion hole. a rotating sleeve rotatably attached to the copying jig outside the tube; and a welding torch fixed to the rotating sleeve, the rotating sleeve welding the tube and the tube sheet. A welding device for welding a tube and a tube sheet, characterized in that the apparatus has a flange portion for positioning the welding torch in the axial direction with respect to the welding portion and forming a passage for shielding gas to the welding portion.