JPH08215921A - Method and device for cutting pipe longitudinally - Google Patents

Abstract

PURPOSE: To prevent a pipe from deforming and the inner surface of the pipe from occurring of flaws and burrs, the deposition of chips and discoloration caused by heat. CONSTITUTION: A pair of upper and lower fixed blades 3a, 3b are juxterposed. A pipe 1 is fixed between both side fixed blades. A shearing blade 5 is adapted to path through gaps 4, 4 between both side fixed blades. Both side parts of the tip side of the shearing blade 5 are inclined rearward. Both side parts of the pipe 1 are pushed and cut off over the whole length by the shearing blade 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for vertically splitting a pipe, in which the pipe is vertically cut at two positions in the circumferential direction in the longitudinal direction to divide the pipe into two in order to perform an inner surface inspection of the pipe and the like. Related to the vertical split device.

[0002]

2. Description of the Related Art In the manufacture of high-quality precision tubes used in nuclear power generation, in order to inspect the quality of the inner surface of the tube, the tube is longitudinally divided into several stages from the intermediate product to the product.

As a method of vertically splitting a pipe, a rotary cutter and a rotary saw blade are well known. Vertical division of a pipe by a cutter is disclosed in, for example, Japanese Patent Laid-Open No. 62-2.
No. 82812.

In vertical division by a cutter, as shown in FIG. 5 (A), a circular cutter arranged in a plane including the center line of the pipe cuts a part of the pipe in the circumferential direction in the longitudinal direction to a full length. . Further, in vertical division with a saw blade, a circular saw blade that is driven to rotate is used as shown in FIG.
However, neither method is suitable as a vertical splitting method for high quality precision tubes used for nuclear power generation.

[0005]

High-quality precision tubes used for nuclear power generation are generally small in diameter, thin in wall thickness, and long in length.
Therefore, the pipe cannot be supported from the inner surface side during vertical division. Further, cutting oil cannot be used at the time of cutting in order to secure the inspection accuracy of the inner surface of the pipe.

When such a pipe is cut in the vertical direction by a cutter, the pipe is crushed and deformed. Also, burrs and flaws occur on the inner surface of the pipe. Cutting with a saw blade does not cause deformation, but it causes discoloration due to flash or heat. Further, cutting chips are generated and adhere to the inner surface, and the cutting chips cause flaws on the inner surface.

Therefore, whichever method is used, the shape and properties of the inner surface are changed, which makes it impossible to inspect accurately. Furthermore, in either method,
Since the tube material is highly alloyed and highly tenacious, there is a problem that the blade may become unusable in a short period of time due to seizure.

An object of the present invention is to provide a vertical pipe splitting method and a vertical pipe splitting method which can divide the pipe into two parts without restraining the pipe from the inner surface side and without changing the shape and properties of the inner surface, and can make the blade last longer. To provide a splitting device.

According to the vertical splitting method of the present invention, two sets of opposed fixed blades are arranged in parallel, and the pipe is fixed between the two fixed blades.
A pair of fixed blades are passed through a shear blade that fits in each gap and both ends of the tip face are inclined rearward to push two positions in the circumferential direction of the pipe vertically over the entire length. is there.

The vertical splitting device of the present invention comprises a pedestal on which a pipe is placed, a pipe clamp means for restraining the pipe on the pedestal from the outer surface side except at least both sides thereof, and a lateral width larger than the outer diameter of the pipe. A reciprocating drive of a shear blade having both ends of the tip surface inclined rearward, a holder that holds the shear blade on a frame and is movable on the frame in the direction of the center line of the pipe, and a holder. The driving means and two sets of upper and lower fixed blades, which are provided on both sides of the tube on the pedestal and are opposed to each other with a gap through which the shear blades pass, are provided on each side.

[0011]

The principle of vertical division in the method and apparatus of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing a typical embodiment of the method of the present invention.

In FIG. 1, a pipe 1 is a pair of upper and lower split molds 2a and 2b.
Is restrained from the outer surface side except both sides. Upper fixed blades 3a, 3a are provided on both side surfaces of the upper split mold 2a, and lower fixed blades 3b, 3b are provided on both side surfaces of the lower split mold 2a.
Are installed respectively. The upper and lower fixed blades 3a and 3b arranged on each side face each other with a predetermined gap 4 therebetween. The gaps 4 and 4 on both sides are located in the water surface including the center line of the pipe 1.

When the pipe 1 is vertically divided, the horizontal shear blade 5 located in the horizontal plane is moved along the center line of the pipe 1. Here, the shear blade 5 has a lateral width larger than the outer diameter of the tube 1, and both side portions are fitted into the gaps 4 and 4 on both sides. Further, the tip surface of the shear blade 5 is perpendicular to the horizontal plane, and both sides thereof are inclined rearward. Therefore, as the shearing blade 5 moves, both sides thereof pass through the gaps 4 and 4 on both sides, and both sides of the tip end face push out both sides of the pipe 1 over the entire length.

In such push-cutting, that is, vertical division by shearing, a force larger than that of cutting by a cutter or a saw blade is applied to the pipe. However, a part of the force acts in the direction of the center line of the tube, and the rest acts as a shearing force on the outer surface side of the tube. Forces acting in the direction of the tube centerline do not cause the tube to deform. Further, the force acting on the outer surface side of the pipe has the fixed blade on the outer surface side thereof and is absorbed by the shearing of the pipe, so that the pipe is not deformed. Therefore, the deformation is prevented even though the tube is not constrained from the inner surface side.

As for the cutting waste, a continuous linear cutting waste 6,
6 is generated on both sides, and no chips are generated. Moreover, the debris is discharged to the outer surface side of the pipe. Therefore, neither sticking of debris to the inner surface of the pipe nor damage to the inner surface of the pipe due to this will occur.

With respect to the wear of the shear blade, due to the principle of shearing, the wear is small even when the pipe material has a high alloying degree and a large stickiness. Rather, a high-alloy material that is tenacious has better shear properties.

Both sides of the tip surface of the shearing blade are required to be inclined rearward, but the inclination should be minimized as long as only the portion that contacts the pipe is inclined. The angle of inclination to the rear is preferably 30 ° to 120 °. If the angle of inclination is too small, the material after longitudinal splitting will deform into an ellipse. On the contrary, if it is too large, the material is bent in the longitudinal direction. The shape of the inclined surface when viewed in plan need not necessarily be a straight line, and may be a curved line.

Although the shear blade is moved to push and cut the pipe in FIG. 1, the shear blade may be fixed and the pipe may be moved together with the fixed blade.

[0019]

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

2 to 4 show an example of the device of the present invention. As shown in FIG. 2 and FIG.
It is equipped with. On the pedestal 10, the pipe clamp means 20, the holder 30, and the fluid pressure cylinder 40 are arranged in tandem from the front to the rear along the center of the apparatus.

As shown in FIG. 4, the pipe clamping means 20 comprises a pair of upper and lower split molds 2 for holding the pipe 1 over its entire length.
1 and 22. The split molds 21 and 22 have U-shaped grooves having a semicircular cross section corresponding to the outer shape of the tube 1 on the opposite surfaces, and restrain the tube 1 from the outer surface side except both side portions.

The lower split mold 22 also serves as a pedestal for the pipe 1, and is bolted to the upper surface of the gantry 10. The upper split mold 21, which holds the tube 1, is bolted to the lower surface of a horizontal beam 23. The beam 23 is supported by a pair of left and right arms 24 and 25 protruding from both sides at three positions in the longitudinal direction. To open the split mold 21, one arm 24 is pivotally supported by a bracket 26 on the frame 10.
Further, in order to fix the split mold 21 to the closed position, the other arm 25 is supported by the pedestal 27 on the pedestal 10 and is fixed by the clamp 28 provided on the pedestal 27.

A pair of upper and lower fixed blades 50a and 50b are arranged on both sides of the split molds 21 and 22 over the entire length. The upper fixed blades 50a, 50a on both sides are bolted to both side surfaces of the upper split die 21, and the lower fixed blades 50b, 50b on both sides are bolted to both side surfaces of the lower split die 22. The upper and lower fixed blades 50a and 50b on each side are opposed to each other with a gap through which a shearing blade 60 described later passes, and come into contact with the outer surfaces of both side portions of the pipe 1 which is sandwiched and fixed between the split molds 21 and 22. ing. The gap between the upper and lower fixed blades on both sides is located in the horizontal plane including the device center.

The holder 30 arranged behind the pipe clamping means 20 has a pair of left and right sliders 31, 31 longer than the split molds 21, 22. The sliders 31, 31 are driven back and forth by a rear fluid pressure cylinder 40. As a result, the sliders 31, 31 are guided by the guides 32, 32 provided on the gantry 10 to reciprocate between the rear of the pipe clamp means 20 and the inside of the pipe clamp means 20. In the pipe clamping means 20, the sliders 31, 31 move outside the upper and lower fixed blades on both sides. 70 is a tube clamp means 20
It is a stopper provided in front of.

A shear blade 60 is attached to the tip of the holder 30. The shear blade 60 is a slider 31,3.
It has a lateral width larger than the gap width between the two, and both side ends thereof are screwed to the respective tip ends of the sliders 31, 31, so that they are held in a horizontal plane including the device center. The tip surface of the shear blade 60 is perpendicular to the horizontal plane, and both sides thereof are symmetrically inclined backward at an angle of about 30 degrees.

In the apparatus shown in FIGS. 2 to 4, the method of the present invention is carried out in the following procedure.

A holder 30 is provided behind the pipe clamping means 20.
The split mold 21 on the upper side is opened in the state in which is retracted. The tube 1 is placed on the split mold 22 on the lower side. The upper split mold 21 is closed and fixed. As a result, the tube 1 is constrained from the outer surface side except the both side portions, and is fixed between the upper and lower fixed blades on both sides with the center line of the tube 1 aligned with the center of the apparatus. Then, the fluid pressure cylinder 40 is operated to move the holder 30 forward.

As the holder 30 advances, the shear blade 60 attached to the tip of the holder 30 passes through the inside of the tube clamping means 20. At this time, both sides of the shear blade 60 are fixed blades 50a,
Both sides of the tube 1 are pressed by the shearing blade 60 over the entire length through the gaps 50b and 50a, 50b.

Using the apparatus shown in FIGS. 2 to 4, the tubes shown in Table 1 were vertically divided without using cutting oil. The moving speed of the shear blade was 1 m / min. As a result, the tube was neither deformed nor discolored by heat. Moreover, the slag was discharged to both sides of the pipe, and the inside surface of the pipe was not damaged by the slag. With the vertical division by the cutter, the service life of the blade reached the limit of use after 20 times and was extended to 600 times.

[0030]

[Table 1]

[0031]

As described above, the longitudinal splitting method and apparatus of the present invention uses shear for vertical splitting to prevent deformation of the pipe even when the pipe is not constrained from the inner surface side. You can In addition, even when cutting oil is not used, discoloration due to burning can be prevented, and at the same time, it is possible to prevent burrs from being generated on the inner surface of the pipe, adhesion of debris, and damage due to the adhesion. Furthermore, the life of the blade can be extended and the cost can be reduced. Therefore, it can be used for vertical division for inspecting the inner surface of a high-quality precision tube used for nuclear power generation, and the reliability of the inspection can be remarkably enhanced, and the cost of the blade can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing one embodiment of the method of the present invention.

FIG. 2 is a side view showing the overall structure of an example of the device of the present invention.

FIG. 3 is a plan view showing the overall structure of an example of the device of the present invention.

4 is a cross-sectional view taken along the line AA of FIGS. 2 and 3. FIG.

FIG. 5 is a schematic view showing a conventional vertical division method.

[Explanation of symbols]

 1 Pipe 2a, 2b, 21, 22 Split Mold 3a, 3b, 50a, 50b Fixed Blade 4 Gap 5,60 Shear Blade 10 Stand 20 Pipe Clamping Means 30 Holder 31 Slider 40 Fluid Pressure Cylinder (Drive Means)

Claims (2)

[Claims] 1. Two sets of fixed blades arranged opposite to each other are arranged in parallel, and in a state in which a pipe is fixed between them, two sets of fixed blades are fitted into the respective gaps, and both side portions are fitted into the respective gaps, and both sides of the front end surface are fitted. A longitudinal splitting method for a pipe, characterized in that two portions in a circumferential direction of the pipe are vertically cut over the entire length by passing a shear blade whose portion is inclined rearward. 2. A pedestal on which a pipe is placed, a pipe clamp means for constraining the pipe on the pedestal from the outer surface side except at least both side portions thereof, and a lateral width larger than the outer diameter of the pipe. Shear blades whose both sides are inclined rearward, a holder that holds the shear blades on the gantry and is movable on the gantry in the direction of the center line of the pipe, drive means for reciprocating the holder, and on the gantry. 2. A vertical splitting device for a pipe, comprising: two sets of upper and lower fixed blades which are provided on both sides of the pipe and are opposed to each other with a gap through which a shear blade passes on each side.