JPH08332627A - Plasma fusion cutting method for concrete structure and its device - Google Patents

Abstract

PURPOSE: To provide a small plasma fusion cutting device suitable for the fusion cutting a concrete structure or the like and also an economical fusion cutting method of high efficiency using the device. CONSTITUTION: While argon, nitrogen and oxygen are jetted out of an open end 18 of a gas flow path 14 by a plasma gas feed mechanism 2, electrodes 11 and 12 composed of soft steel pipes are loaded by a plasma power source 3 of constant-current type and discharge is carried out at the open end 18 to form an argon jet plasma gas flow. A material 6 to be fusion cut as a concrete lump is fusion cut and bored by high temperature jet plasma gas. An electrode material melted by discharge is carried to a heating section for the material 6 to be fusion cut by the jet plasma gas, where the electrode material is reacted with the concrete to form a low melting point product and accelerate the fusion cutting. The efficiency of fusion cutting is further improved by feeding powder of iron, aluminum or the like by a powder feed mechanism 4. Oxygen can also be fed by an oxygen gas feed mechanism 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a method and apparatus for thermally fusing structural materials such as reinforced concrete, mineral materials such as rocks and refractory bricks.

[0002]

2. Description of the Related Art Conventionally, as a method for thermally fusing structures such as reinforced concrete, rocks, and mineral materials such as refractory bricks, a flame such as a combustion cutting method using an oxygen lance defined in DIN 32510 is used. Various methods have been developed, including those using a jet as a heat source, and utilizing high temperatures such as plasma and laser.

In the thermal fusing of mineral materials, the higher the temperature of the heat source used, the faster and more efficient fusing is possible.
In that respect, plasmas and lasers can be said to be more advantageous heat sources than flame jets. However, the laser generator is expensive, and in particular, there is a difficulty in that a large-capacity laser generator is required for treating a large structure such as a concrete structure. On the other hand, plasma is a heat source that can obtain a high temperature relatively inexpensively, and has been conventionally used for welding and fusing of metallic materials.

By the way, the plasma torch conventionally used basically uses non-consumable electrodes, and measures are taken to protect the electrode parts, for example, by cooling the electrode parts with water. Therefore, the structure of the electrode part is complicated and the size of the electrode part is large.

[0005]

However, according to such a conventional plasma torch, it is difficult to hold the torch because the moving distance of the torch becomes long when fusing large-sized products such as concrete structures. In particular, in the work such as drilling, if the torch size is large, disadvantages such as the difficulty of holding the torch and an unnecessarily large inner diameter of the hole to be drilled occur.

From the above viewpoints, an object of the present invention is to provide a small-sized plasma fusing device suitable for fusing concrete structures and the like, and an economical fusing method using the same. It is in.

[0007]

In order to solve the above-mentioned problems, a plasma fusing apparatus for a concrete structure according to the present invention comprises: (1) a metal hollow rod-shaped first electrode that penetrates through a hollow portion of a metal; A rod-shaped second electrode is provided, an insulator is provided between the first electrode and the second electrode, and gas can flow between the first electrode and the second electrode. A plasma gas supply mechanism that is connected to one end of the first electrode and has a plasma gas supply mechanism that supplies a plasma gas to the gas flow path, the first electrode and the second electrode. And a plasma power supply for applying a voltage to the electrodes.

(2) In the plasma fusing device for a concrete structure according to (1), the powder is fed to the gas flow path, which is connected between the first electrode and the plasma gas supply mechanism. A powder supply mechanism is provided. (3) In the plasma fusing device for a concrete structure according to (1) or (2), in place of the rod-shaped second electrode, a second electrode having a gas communication hole penetrating in the longitudinal direction is provided, An oxygen gas supply mechanism connected to one end of the second electrode is provided.

(4) In the plasma fusing device for a concrete structure according to any one of (1) to (3), the insulator is a flux. Also,
In order to solve the above-mentioned problems, the method for plasma-cutting a concrete structure according to the present invention comprises: (5) a metal hollow rod-shaped first electrode and a metal electrode provided through the hollow portion of the first electrode. A gas composed of one or two kinds of nitrogen and argon, or a gas composed of one or two kinds of nitrogen and argon and oxygen is jetted from one end of an electrode portion including a second electrode. , The arc is generated between the end of the first electrode and the end of the second electrode, and the gas to be ejected is plasma, and the ejected plasma gas, the first electrode and the second electrode It is characterized in that the concrete structure is melt-cut by the molten particles generated by the oxidation and melting of the metal forming the electrode.

(6) In the method for plasma-cutting a concrete structure according to (5), iron, aluminum, iron oxide, alumina, fluorspar, ilmenite, rutile and boride, which are in the form of powder, are added to the jetted plasma gas. It is characterized in that any one or two or more of them are ejected. (7) In the method for plasma-cutting a concrete structure according to (5) or (6), a gas through hole penetrating in a longitudinal direction is provided inside the second electrode, and the jetted plasma gas is discharged from the gas through hole. It is characterized in that a gas consisting of one or more of nitrogen, argon and oxygen is ejected toward the central portion.

(8) In the plasma fusing method for a concrete structure according to (5), (6) or (7), the second electrode has a gas through hole, and the gas through hole has a linear or powdery shape. It is characterized by inserting one or two kinds of iron or aluminum.

[0012]

The metal hollow rod-shaped first electrode and the metal rod-shaped second electrode form an electrode portion for generating the jetted plasma gas. The insulator provided between the side surface of the first electrode and the side surface of the second electrode electrically insulates the side surface of the first electrode and the side surface of the second electrode, and discharges from this portion. Acts to prevent. As a result, the discharge can be generated only at the ends of the electrode portion. Note that the insulator does not have to cover the entire surface of the electrode, and may be provided so as to prevent discharge at a portion other than the required end face of the electrode portion. The material forming the insulator may be an insulating material having appropriate heat resistance. The material of the insulator is preferably flux.

The gas flow path provided between the first electrode and the second electrode is for supplying plasma gas to the discharge end of the electrode portion. Further, the effect of the gas flow path is to cool the side surfaces of the first electrode and the second electrode by the gas flowing through the gas flow path. The plasma gas supply mechanism has a function of injecting plasma gas from one end of the electrode portion, supplying a required amount of plasma gas to the discharge portion at the other end of the electrode portion through a gas flow path in the electrode portion, and ejecting the gas.

The plasma power source includes the first electrode and the second electrode.
A voltage is applied to the electrodes of the plasma gas to generate a discharge in the plasma gas jetting portion, and the plasma gas has a function of turning into plasma.
The powder supply mechanism provided in another embodiment of the present invention is
It has a function of adding a required amount of powder to the plasma gas sent by the plasma gas supply mechanism. The gas conduction hole penetrating in the longitudinal direction of the second electrode provided in the other embodiment of the present invention is an oxygen gas passage for feeding the oxygen gas to the central portion of the ejected plasma gas. .

Further, the oxygen gas supply mechanism provided in another embodiment of the present invention has a function of ejecting a required amount of oxygen gas to the central portion of the ejected plasma gas through the gas conducting hole provided in the second electrode. Hold. In the plasma fusing method for a concrete structure according to the present invention, an arc is generated between the end of the first electrode and the end of the second electrode, and at the same time, gas is ejected from the end of the electrode, and the ejection is performed. The gas is turned into plasma. The jetted plasma gas is jetted onto the melted object to heat and melt the melted object to melt and punch. The plasma generator of the present invention is smaller than the conventional plasma torch, and is capable of bringing the highest temperature part of the ejected plasma close to the part to be melted and efficiently heating and melting it for melting and punching.

Due to the heat of the jetted plasma gas, the electrodes are successively melted and consumed from the discharge end. The melted electrode metal becomes molten particles and is carried by the ejected plasma gas, and reaches the surface of the melted object exposed to the ejected plasma gas. Here, the molten particles react with the melted material to form a reaction product having a low melting point, and promote the dissolution of the melted material. Therefore, the metal material of the first electrode and the second electrode is preferably a metal that reacts with the material to be melted to form a low melting point reaction product.

Further, in order to avoid the rapid exhaustion of the electrode portion, the electrode portion approaches the high temperature plasma, and especially when the deep hole is bored, the first electrode contacts the high temperature exhaust gas. It is preferable that the electrode material has a high melting point. Preferably, iron is used as the electrode material. As the gas to be turned into a plasma, a gas composed of one or more of nitrogen, argon and oxygen is used.
This is because it is easy to obtain stable high-temperature plasma with these gases, and it is relatively inexpensive and economical. Also,
The reason why oxygen is used in addition to nitrogen and argon is that oxygen accelerates the oxidation of the molten particles and lowers the melting point of the reaction product of the molten particles and the melt-cut material.

Regarding the addition of oxygen, any one of nitrogen, argon and oxygen is introduced toward the central portion of the ejected plasma gas from the gas conduction hole provided inside the second electrode.
It can be ejected as a gas of one kind or two or more kinds. Oxygen is diluted with nitrogen, argon or the like to adjust its activity before use. As another embodiment of the present invention, in addition to the jetted plasma gas, any one or two of powdered iron, aluminum, iron oxide, alumina, fluorspar, ilmenite, rutile and boride is used.
Eject seeds or more. Each of these metals and ores reacts with the melted object to form a compound having a low melting point, and thus has an effect of facilitating the melt-cutting / perforation of the melted object. In addition, the addition of the above-mentioned metals makes it possible to obtain the heat of oxidation of these metals. By the simultaneous addition of aluminum and iron oxide, a high heat generation due to the Thermite reaction can be obtained.

The above-mentioned metal and ore are made into a powder because the powder is easy to carry by gas and the activity of the powder having a large surface area is utilized.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the plasma fusing apparatus for concrete structures of the present invention will be described below with reference to the drawings. Figure 1
It is a typical layout showing the composition of the example of the plasma fusing device of the concrete structure of the present invention. This plasma fusing apparatus mainly includes an electrode unit 1, a plasma gas supply mechanism 2, a plasma power supply 3, a powder supply mechanism 4 and an oxygen supply mechanism 5.

The electrode portion 1 has an outer diameter of 17.5 mm and a wall thickness of 2.
First electrode 11 made of 3 mm mild steel pipe and 9 m outside diameter
m and a second electrode 12 made of a mild steel pipe having a wall thickness of 1 mm, and an insulator 13 having a thickness of 1.5 mm was formed on the outer periphery of the second electrode 12 using an ilmenite-based flux. A gas flow path 14 was formed between the first electrode 11 and the second electrode 12. One end of the electrode part 1 was sealed with an ebonite sealing tool 15, and the first electrode 11 and the second electrode 12 were insulated and fixed. The other end of the electrode part 1 is left open and the open end 18
And The length of the electrode part 1 was 1 m.

In order to adjust the cross-sectional area of the gas passage hole 17 provided in the second electrode 12, as shown in FIG. 2, the diameter is 3 mm.
Five adjusting members 16 made of the above mild steel wire were inserted into the gas conducting holes 17. The plasma gas supply mechanism 2 includes a gas cylinder, a pressure reducer, a flow rate controller, a gas mixer, and the like, which are not shown.
The plasma gas supply pipe 21 connects the plasma gas supply mechanism 2 and the electrode portion 1 and guides the plasma gas to the gas flow path 14.

A powder supply mechanism 4 equipped with a powder tank, a powder cutting device and the like (not shown) was provided connected to a part of the plasma gas supply pipe 21. The oxygen gas supply mechanism 5 includes a gas cylinder, a pressure reducer, a flow rate controller, a gas mixer, and the like, which are not shown. The oxygen gas supply pipe 51 connects the oxygen gas supply mechanism 5 and the electrode portion 1 and guides the oxygen gas to the gas communication hole 17.

The plasma power source 3 is a constant current type power source, and the first
The electrode 11 was connected to the positive electrode, and the second electrode 12 was connected to the negative electrode. (Embodiment 1) Using the above apparatus, first, the plasma gas supply mechanism 2 was operated to send argon to the plasma gas supply pipe 21 and jetted from the open end 18 through the gas flow path 14.
At this time, the pressure of argon was 10 atm.

Next, the plasma power supply 3 was operated to apply a voltage between the first electrode 11 and the second electrode 12 to generate a discharge at the open end 18 of the electrode portion 1. Discharge current is 700
A. By the above operation, a jet plasma gas of argon jetted from the open end 18 was obtained. Thickness 100mm
The concrete plate of No. 2 is used as the material to be melted 6, and the blown plasma gas is applied to the perforated portion to start melting. The fusing was performed while adjusting the position of the electrode part 1 according to the change of the fusing position and the consumption of the electrode part 1.

As a result of the above, a through hole having a diameter of about 50 mm was obtained by the fusing work for 60 seconds. (Embodiment 2) In addition to the adjustment of the apparatus in Embodiment 1, the oxygen supply mechanism 5 is operated to send a gas of argon + 10% oxygen to the oxygen gas supply pipe 51, and the gas is passed through the gas communication hole 17 from the open end 18. It gushed. At this time, argon + oxygen 10%
The gas pressure was 8 atm.

In the same manner as in Example 1, the concrete plate having a thickness of 100 mm was used as the object to be melted 6, and as a result of the melting work, 20
A through hole having a diameter of about 25 mm was obtained by a fusing operation for sec. (Example 3) In addition to the adjustment of the apparatus in Example 2, the powder supply mechanism 4 was further operated to add 100 to 200 mesh iron powder to the plasma gas at a rate of 250 g / min for the experiment.

In the same manner as in Example 1, a concrete plate having a thickness of 100 mm was used as the object to be melted 6, and the result of the melting work was 10
A through hole having a diameter of about 25 mm was obtained by a fusing operation for sec. Example 4 In addition to the iron powder added to the plasma gas in Example 3, 100 mesh aluminum powder was further added to the plasma gas at a rate of 17 g / min for an experiment.

In the same manner as in Example 1, a concrete plate having a thickness of 100 mm was used as the object to be melted 6, and the result was 6 s.
A through hole having a diameter of about 25 mm was obtained by the fusing work of ec. (Comparative Example 1) In the apparatus of Example 3, the plasma power source 3
The experiment was conducted with the device configuration excluding. The experimental conditions are those of Example 4 except that the plasma power source 3 is not operated and the gas supplied from the oxygen supply mechanism 5 is 100% oxygen.
An experiment was conducted under the same conditions as. In this case, the gas ejected from the open end 18 was ignited by using an ignition device.

As a result of the fusing work of a 100 mm-thick concrete plate as the fusing target 6, a fusing work of 180 sec yielded a through hole having a diameter of about 50 mm. As described above, according to the method and apparatus of the present invention, as described in the embodiments, it is possible to very effectively perform the fusing and perforation of the melted object.

[0031]

As described above, the electrode portion in the plasma fusing apparatus for concrete structure of the present invention is cooled by the plasma gas flowing through the gas flow path provided between the first electrode and the second electrode. Has no special cooling mechanism and is therefore a very small, simple and inexpensive structure. This makes it possible to efficiently form deep holes having a relatively small diameter while utilizing the high temperature of plasma.

The electrode is consumed by arc heat, but the product produced by melting of the electrode is utilized for promoting fusing, which is extremely efficient. In the method of the present invention, in accordance with the use of high temperature plasma, heat of reaction between oxygen and the electrode material and the additive metal powder, high exothermicity due to the thermite reaction is used, and further, the material to be melted by electrode material and the additive powder material It is possible to effectively perform fusing and perforation by utilizing the lowering of the melting point.

The method and apparatus of the present invention are not limited to concrete structures, but include mineral materials such as rocks and refractory bricks,
It can also be applied to melting of refractory metal materials that are difficult to melt with a flame jet.

[Brief description of drawings]

FIG. 1 is a schematic layout diagram showing a configuration of an embodiment of a plasma fusing device for a concrete structure of the present invention.

FIG. 2 is a cross-sectional view of an electrode portion according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 electrode part 2 plasma gas supply mechanism 3 plasma power supply 4 powder supply mechanism 5 oxygen supply mechanism 6 to-be-melted material 11 1st electrode 12 2nd electrode 13 insulator 14 gas flow path 15 sealing tool 16 adjusting material 17 gas conduction Hole 18 Open end 21 Plasma gas supply pipe 51 Oxygen gas supply pipe

Claims (8)

[Claims] 1. A metal rod-shaped second electrode is provided so as to penetrate the hollow portion of the metal hollow rod-shaped first electrode, and the first electrode is provided.
An electrode section having an insulator between the first electrode and the second electrode, and having a gas flow path through which gas can flow between the first electrode and the second electrode; A plasma gas supply mechanism that is connected to one end of the electrode and supplies plasma gas to the gas flow path, and a plasma power supply that applies a voltage to the first electrode and the second electrode. Plasma cutting equipment for concrete structures. 2. The powder supply mechanism, which is connected between the first electrode and the plasma gas supply mechanism, and which supplies powder to the gas flow path. Plasma cutting equipment for concrete structures. 3. A rod-shaped second electrode is replaced with a second electrode having a gas communication hole penetrating in the longitudinal direction, and an oxygen gas supply mechanism connected to one end of the second electrode. The plasma fusing device for a concrete structure according to claim 1 or 2, characterized in that. 4. The plasma fusing device for a concrete structure according to claim 1, wherein the insulator is a flux. 5. A metal hollow rod-shaped first electrode and the first electrode.
From one end of an electrode portion including a second electrode made of metal, which penetrates through the hollow portion of the electrode, and a gas formed of one or two kinds of nitrogen and argon, or one kind of nitrogen and argon. Or, a gas composed of two kinds and oxygen is jetted out, and an arc is generated between the end portion of the first electrode and the end portion of the second electrode to make the jetted gas into plasma, Plasma gas and the first
A method for plasma-cutting a concrete structure, characterized in that the concrete structure is melt-cut by the molten particles formed by the oxidation and melting of the metal forming the electrode and the second electrode. 6. In addition to the jetted plasma gas, powdered iron, aluminum, iron oxide, alumina,
The plasma fusion cutting method for a concrete structure according to claim 5, wherein any one or more of fluorspar, ilmenite, rutile and boride is ejected. 7. A gas through hole penetrating in a longitudinal direction is provided inside the second electrode, and any one of nitrogen, argon and oxygen is provided from the gas through hole toward the center of the jetted plasma gas, or The plasma fusion cutting method for a concrete structure according to claim 5 or 6, wherein a gas composed of two or more kinds is ejected. 8. The fifth electrode according to claim 5, wherein the second electrode has a gas through hole, and one or two kinds of linear or powdery iron or aluminum are inserted into the gas through hole. Alternatively, the method for plasma-cutting a concrete structure according to Item 7.