JP3032182B2 - Cutting machine by abrasive jet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abrasive jet cutting apparatus having an outer periphery coated with an air jet.

[0002]

2. Description of the Related Art A cutting method using an abrasive jet, in which a high-pressure water mixed with an abrasive is sprayed from a nozzle, has been widely used for cutting steel or concrete.

[0003] Further, underwater, cutting of steel materials and concrete, for example, H steel, RC in shielding work
It is used for cutting piles, sheet piles, etc., and is also used for dismantling offshore structures underwater.

By the way, the cutting ability of this abrasive jet is attenuated in the air as the distance from the nozzle outlet to the object to be cut (stand-off distance) increases. This phenomenon is caused by the jet flow (abrasive jet). This is considered to be caused by a decrease in the convergence due to the diffusion and a decrease in the injection speed due to the resistance of the surrounding fluid.

[0005] In water, the resistance of the surrounding fluid is greater than that in the air, so that the distance attenuation of the cutting ability becomes more remarkable.

For example, FIG. 16 shows the result of cutting a steel material by abrasive jet in comparison between the air and the water. From this figure, when the stand-off distance is 150 mm or more, the difference between the air and the water becomes remarkable. , 250 mm or more, it can be confirmed that the cutting ability in water is almost lost.

As described above, when the stand-off distance increases in water, the cutting ability rapidly decreases.
When cutting H steel, it is easy to cut the flange on the front side, but there is a problem that the flange on the back side and the web portion cannot be cut.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an abrasive jet-based cutting apparatus which reduces the attenuation of the cutting ability in water as much as possible.

Another object of the present invention is to provide a cutting device using an abrasive jet that can cut a workpiece such as H steel having a different cutting load depending on a cutting location in a short time.

[0010]

[0011]

According to the present invention, in an abrasive jet cutting apparatus in which an air jet is jetted from the periphery of an abrasive jet and the outer periphery is coated with the air jet, an injection hole for jetting the abrasive jet is provided. An inner jet having an inner pipe, and an outer pipe having an injection hole that covers the outer periphery of the inner tube and jets an air jet, and is provided in the injection hole and has an outer periphery coated with an air jet of an abrasive jet. The injection nozzle moves back and forth by the feed drive unit, and rotates by the rotary drive unit,
The angle is changed by the tilt drive unit.

[0012]

[0013]

[0014]

The present invention is constituted as described above. In the underwater cutting, the surrounding water and the abrasive jet are coated with a curtain of air by an air jet injected from the periphery of the abrasive jet, and the resistance of the water is reduced. And attenuating the cutting ability can be prevented, so that the ability equivalent to the aerial cutting can be obtained.

The stand-off distance can be shortened by moving the injection nozzle to a required distance with respect to the cutting portion of the workpiece or by inclining the injection nozzle at a required angle, thereby preventing the attenuation of the cutting ability. In the related art, cutting can be performed even on a workpiece having a depth and a wide cutting load, such as H steel.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the "abrasive jet whose outer periphery is coated with an air jet" is hereinafter referred to as an "air-coated abrasive jet".

FIG. 1 shows a basic example of a nozzle for performing a cutting method using an air-coated abrasive jet according to the present invention. ,
And an outer tube 3 having an air jet injection hole for injecting an air jet B over the outer periphery of the inner tube 2.

According to the nozzle 1, an air jet B is jetted from the periphery of the abrasive jet A to create a curtain of air between the surrounding fluid, that is, water and the abrasive jet, so that the resistance of the water is reduced and cutting is performed. Prevent decay of ability.

FIG. 15 shows a result of cutting a steel material in water by an air-coated abrasive jet (ACAJ) in comparison with data of cutting a steel material in water and air by a normal abrasive jet (AJ).

As is clear from this figure, the air-coating abrasive jet (ACAJ) system has a greatly improved cutting ability, and can obtain almost the same performance as in-air cutting.

The pressure of the air jet is in the range of atmospheric pressure +2 to 3 kgf / cm ² . The air flow rate of the air jet is set to 1 to ³ Nm ³ / min.

FIGS. 2 to 5 show examples of air-coated abrasive jet injection nozzles. FIG. 2 shows a ring-jet type air-coated abrasive jet injection nozzle 1A, which has the shortest stand-off distance. be able to. And the flow rate can be adjusted.

FIG. 3 shows a ring jet type No. 2 air-coated abrasive jet injection nozzle 1B, which can minimize the actual stand-off distance. The injection angle is 0 degrees.

FIG. 4 shows a tapered jet type air coating abrasive jet injection nozzle 1C, which can forcibly converge the air jet at the tapered portion.

FIG. 5 shows a Laval jet type air-coating abrasive jet injection nozzle 1D. The air jet can be appropriately expanded by a diverging pipe to achieve supersonic flow.

FIG. 6 shows cutting of the H steel K by the air coating abrasive jet. When cutting the H steel K, if the axis of the jet J is perpendicular to the flange h of the H steel K, it becomes difficult to cut the portion of the web w.
An angle is provided as shown in FIG. This angle is 25 degrees.

The nozzle 1 is moved in the direction of the arrow, and the moving speed is different for the portions A, B1, B2, and C in the figure because the energy required for cutting is different. The setting was 12 minutes, B1 part 20 minutes, B2 part 13 minutes, and C part 0.5 minutes. As a result, it was possible to cut the H steel K in about 45 minutes.

FIG. 7 shows a variable-angle cutting device suitable for cutting in the above-described embodiment. An abrasive hose 4 and a high-pressure hose 5 are connected to the nozzle 1. Is connected to an abrasive supply device (not shown), and the high-pressure hose 5 is connected to a high-pressure swivel joint 5a.
Is also connected to a high-pressure air source (not shown).

A rotary drive unit 6 for rotating the injection nozzle 1,
An inclination drive unit 7 that changes the angle is provided, and the entire apparatus is transported back and forth by a feed drive unit 8 and a slide unit 9.

According to this apparatus, a predetermined angle is given to the nozzle 1 by the tilt drive unit 7, and the abrasive material hose 4 is transported back and forth by the feed drive unit 8 and the slide unit 9.
The abrasive and the high-pressure air are supplied to the nozzle 1 by the high-pressure hose 5 and the air coating abrasive jet is jetted to perform the cutting shown in FIG. Further, as shown in FIGS. 8 and 9, the tilt drive unit 7 and the rotation drive unit 6 can be driven to cut the workpiece Z in a wide range in a concentric Z1.

FIGS. 10 to 13 show an example of cutting when H steel is present inside the pile. The pile X containing the H steel K shown in FIG. 10 is cut in parallel to the straight line as shown in FIGS. The injection angle of the nozzle 1 is inclined to cut from the already cut portion c.

FIG. 14 shows an embodiment in which the air-coating abrasive jet 1 is applied to the cutter head C of the shield excavator S. Obstacles such as remaining piles buried underground during excavation during shield work can be removed by cutting or crushing. The symbol M is a cutting drive for an abrasive jet, P is a high-pressure generator, G
Denotes an abrasive supply device.

[0034]

According to the present invention, a curtain of air is formed between the surrounding fluid, that is, water, and the abrasive jet by the air jet injected from the periphery of the abrasive jet, the resistance of the water is reduced, and the cutting is performed. Preventing the ability from declining, it is possible to obtain almost the same performance as in aerial cutting.
The stand-off distance can be shortened by moving the injection nozzle with respect to the workpiece or tilting it to the required angle, preventing attenuation of the cutting ability and supporting deep objects. can do.

Therefore, it can be suitably used in water for cutting steel materials and concrete, for example, cutting underground obstacles such as H steel, RC piles and sheet piles in shield construction. It can also be used in the sea for dismantling offshore structures. And underground work can be used in the same way because it is almost always underwater.

[Brief description of the drawings]

FIG. 1 is a schematic view of an air-coated abrasive jet.

FIG. 2 is a schematic view of a ring jet type 1 air-coated abrasive jet.

FIG. 3 is a schematic diagram of a ring jet type 2 air-coated abrasive jet.

FIG. 4 is a schematic view of a tapered jet type air coating abrasive jet.

FIG. 5 is a schematic diagram of a Laval jet air coating abrasive jet.

FIG. 6 is an explanatory diagram showing cutting of H steel by an air-coated abrasive jet.

FIG. 7 is a vertical cross-sectional view of a variable angle cutting device for an air-coated abrasive jet.

FIG. 8 is an explanatory view of cutting a workpiece by tilting and rotating a nozzle of an air-coated abrasive jet.

FIG. 9 is a plan view of FIG. 8;

FIG. 10 is a cross-sectional view of a pile containing H steel as an object to be cut.

FIG. 11 is a sectional view showing a first step of the cutting shown in FIG. 10;

FIG. 12 is a sectional view showing a step of cutting the flange portion of FIG. 10;

FIG. 13 is a sectional view showing a step of cutting the web portion of FIG. 10;

FIG. 14 is a sectional view showing an embodiment in which an air-coated abrasive jet is applied to a shield excavator.

FIG. 15 is a graph showing the effect of air coating when a steel material is cut in water by an air coating abrasive jet.

FIG. 16 is a graph showing the underwater cutting ability of a conventional abrasive jet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air coating abrasive jet injection nozzle 2 ... Inner tube provided with an abrasive jet injection hole 3 ... Outer tube provided with an air jet injection hole 4 ... Abrasive material hose 5 ... High pressure hose 6 ... Rotary drive unit 7 ... Nozzle tilt drive unit 8 ... Feed drive unit 9 ... Slide unit A ... Abrasive jet B ... Air jet

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kosuke Shiota Kashima Construction Co., Ltd. 1-2-7 Moto-Akasaka, Minato-ku, Tokyo (56) References JP-A-5-185400 (JP, A) JP-A-4-240074 (JP, A) JP-A-5-50400 (JP, A) JP-A-7-1398 (JP, A) JP-A-1-153299 (JP, A) JP-A-5-78472 ( JP, U) JP 6-45120 (JP, B2) JP 6-59626 (JP, B2) JP 4-57471 (JP, B2) JP 63-34242 (JP, B2) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B24C 5/02-5/04 B26F 3/00 E04G 23/08

Claims (1)

(57) [Claims] 1. A cutting device using an abrasive jet, which jets an air jet from the periphery of an abrasive jet and coats the outer periphery with an air jet,
An inner pipe having an injection hole for injecting an abrasive jet,
An outer tube having an injection hole for covering the outer periphery of the inner tube and ejecting an air jet, and an abrasive jet injection nozzle provided in the injection hole and coating the outer periphery with an air jet is provided by a feed drive unit. A cutting device using an abrasive jet, characterized in that the cutting device moves back and forth, is rotated by a rotary drive unit, and is variable in angle by a tilt drive unit.