JPH1018612A - Concrete cutting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly promote cutting efficiency with the synergistic effect by radiating laser beams to concrete to melt it, and injecting high pressure water to quickly cool and crush the molten concrete to remove. SOLUTION: A laser gun 3 condenses laser beams from a laser generator 7 through a condenser 9 to irradiate the laser beams to a place to be cut. A high pressure water injection nozzle 4 is equipped with an oscillation mechanism oscillating in the cutting direction, and high pressure water is injected from a high pressure water generator 11. The laser is condensed through the laser gun 3 to increase energy density, the heat energy is used to melt concrete 1, the high pressure water is injected to the molten part from the high pressure water injection nozzle 4, and the concrete 1 is crushed with water energy. Then, since the concrete 1 heated with high temperature from the laser is quickly cooled by high pressure water injection, crush efficiency is greatly promoted, and dross melted with the laser is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a concrete cutting method applied to demolition and repair work of a concrete structure.

[0002]

2. Description of the Related Art Conventionally, concrete cutting using a laser is performed by condensing a laser beam to increase the thermal energy density of the laser, thereby melting and removing the object to be cut. .

[0003]

In this case, in order to increase the cutting efficiency, the molten dross that absorbs and reflects the thermal energy of the laser beam is efficiently removed so that the laser beam always hits new concrete. There is a need to. Generally, dross is blown off by blowing air, nitrogen, inert gas, etc., but it is not enough, and concrete cutting is different from plate-like cutting of iron plate etc. In addition, since the beam and gas cannot penetrate, it is difficult to discharge dross, and the energy of the laser is not effectively used.
For this reason, there is a problem that the cutting efficiency is lower than the cutting method using a diamond blade or the like.

The present invention solves the above-mentioned conventional problems. The cutting efficiency can be greatly improved by the synergistic effect of melting by a laser beam and rapid crushing and dross removal by a water jet. It is an object to provide a concrete cutting method.

[0005]

For this purpose, the concrete cutting method of the present invention irradiates a concrete with a laser beam to melt the concrete, and at the same time, jets high-pressure water to rapidly cool, crush and remove the molten concrete. It is characterized by doing.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged sectional view showing one embodiment of a concrete cutting method according to the present invention.

FIG. 1 shows a cut slit (groove) 12.
The laser gun 3 and the high-pressure water injection nozzle 4 are provided in the suction device 2. The suction device 2 has a suction port 5 and discharges the melted and crushed dross together with water by a vacuum pump 6.

The laser gun 3 condenses a laser beam sent from a laser generator 7 by an optical fiber cable 8 by a condenser lens 9 and irradiates the laser beam to a cut portion. Air can be supplied from the generator 10, thereby preventing water or dross from entering the laser optical system (protecting the optical system such as a lens). The laser used has a wavelength that is hardly absorbed by water, such as an iodine laser.

The high-pressure water injection nozzle 4 has a swing mechanism (not shown) that swings in the cutting direction B as shown by an arrow A in the figure, and injects high-pressure water from the high-pressure water generator 11. Nozzle diameter is about 5mm, pressure of high pressure water is 1000kg
/ Cm ² or more and a flow rate of about 5 liter / minute are preferred.

The concrete cutting method having the above-mentioned structure will be described. The laser gun 3 focuses a laser beam to increase the energy density, uses the thermal energy to melt the concrete 1, and applies high pressure to the melted portion. High-pressure water is injected from the water injection nozzle 4 to crush the concrete 1 with water energy. At this time, concrete heated at a high temperature by the laser is rapidly cooled by high-pressure water jetting, so that the crushing efficiency is significantly improved, and dross melted by the laser is eliminated by the water jet. This is considered to be due to the decrease in concrete strength at high temperature and the effect of quenching unsteady thermal stress due to heat transfer accompanied by boiling at the collision portion of the water jet, and the cutting ability was significantly increased. Therefore, a high-pressure, low-water-volume water is instantaneously injected into the high-temperature, molten concrete by the laser beam to rapidly cool the concrete, and at the same time, a deep slit can be cut at a high speed in order to discharge dross reflecting and absorbing the laser beam.

[0011]

As is clear from the above description, according to the present invention, the cutting efficiency can be greatly improved by the synergistic effect of melting by a laser beam and quenching crushing and dross removal by a water jet. It is possible to provide a method of cutting concrete with low vibration and low noise.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a concrete cutting method according to the present invention.

[Explanation of symbols]

1 ... concrete, 2 ... suction device, 3 ... laser gun,
4: High pressure water injection nozzle

Claims (1)

[Claims] 1. A concrete cutting method comprising: irradiating a laser beam onto concrete to melt the concrete; and jetting high-pressure water to rapidly cool, crush, and remove the molten concrete.