Apparatus and method for cutting object to be cut

Abstract

To provide an object cutting device which can further reduce environmental influences.SOLUTION: An object cutting device comprises: a cutting torch 11 for cutting a structure 32 that can be used while being held by hand; a supply hose 18 for supplying at least fuel gas and powders to the cutting torch 11; and a dust collecting device 13 which can recover powder dusts generated by cutting of the structure 32. The dust collecting device 13 comprises: a chamber part 41 which surrounds at least a portion of the structure 32 cut by the cutting torch 11; a dust collector 43 for recovering powder dusts; and a transport part 42 for transporting the powder dusts to the dust collector 43.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for cutting, for example, reinforced concrete and other objects to be cut. [Background technology]

[0002] In recent years, there has been an increase in cases where demolition work is required to remove existing structures before construction of new buildings begins. When demolishing existing structures, a method that uses large breakers is generally used. However, one of the issues is the vibrations caused by the work, which affects the surrounding environment. Furthermore, in underground areas, despite the large cross-section of the foundation structure, work must be done in a small space, which limits the use of large machinery. There is a demand for the development of a construction method that can solve these issues.

[0003] Currently, there are cutting methods using wire sawing and core boring as methods for suppressing vibrations that occur when demolishing large cross-section concrete structures. However, the former has the problem that the wire saw must be installed on the outer periphery of the cutting area. The latter has the problem that steel materials such as rebars and steel frames that make up the structure can hinder core boring. Therefore, the inventors have developed a cutting device and cutting method that uses a hydrogen-based mixed gas to improve the efficiency of demolishing underground concrete structures and reduce the impact on the surrounding environment (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-138303 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the cutting device and the cutting method using the mixed gas are effective in increasing the efficiency of dismantling and reducing the impact on the surrounding environment. Therefore, it is desirable to improve these cutting devices and cutting methods so as to further reduce the impact on the environment.

[0006] An object of the present invention is to provide an apparatus and method for cutting an object, which can further reduce the impact on the environment. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a cutting torch that can be held by hand and used to cut an object to be cut, a supply hose for supplying at least fuel gas and powder to the cutting torch; a dust collecting device capable of sucking in both exhaust gas and dust generated by cutting the object to be cut; a chamber section surrounding at least a portion of the object to be cut by the cutting torch, the chamber section having a work side opening into which the cutting torch can be inserted and which guides the cutting torch movably; The present invention relates to an apparatus for cutting an object to be cut, comprising:

[0008] In order to solve the above problems, the present invention provides Cutting object a hand-held cutting torch for cutting the At least fuel gas and Bipa a supply hose for supplying wood to the cutting torch; The above Cutting object and a dust collector capable of collecting dust generated by cutting. Cutting object A cutting method comprising the steps of: The cutting torch is used while being held by hand, In the dust collecting device, Cutting object Dust generated by cutting Inhaled with exhaust gas While Cutting object The present invention relates to a method for cutting a structure, comprising the steps of: Effect of the Invention

[0009] According to the present invention, it is possible to provide an apparatus and a method for cutting an object, which can further reduce the impact on the environment. [Brief description of the drawings]

[0010] [Figure 1] 1A to 1C are diagrams for explaining a cutting device and a cutting method according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining a cutting torch. [Diagram 3] FIG. 2A is a front view for explaining the vicinity of the tip of a cutting torch in an isolated state, and FIG. 2B is a cross-sectional view taken along line AA in FIG. [Figure 4] 2(c) is a front view of the cutting torch in FIG. 2(a) rotated 90 degrees around the longitudinal axis, and (d) is a cross-sectional view taken along line BB in (c). [Diagram 5] FIG. [Figure 6] FIG. 2 is a diagram for explaining cutting of a structure by a cutting torch. [Figure 7] 13 is a diagram for explaining the state in which a cutting torch has entered the cleavage portion. FIG. [Figure 8] 13(a) to 13(d) are diagrams for explaining other examples of the fire nozzle receiver. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The cutting device and cutting method of the present invention will be described below. Fig. 1 shows a schematic diagram of a cutting device 10 according to one embodiment of the present invention. This cutting device 10 includes a cutting torch 11, an adjustment device 12, and a dust collection device 13. Of these, the cutting torch 11 has a cylindrical main body 14, and the axial length of the main body 14 is long enough to be held by a cutting operator with one or both hands. The overall length, external dimensions, and weight of the cutting torch 11 are such that a worker can hold it in his or her hand (with a glove on for safety) and perform work flexibly.

[0012] As shown in Fig. 2, a flame nozzle 15 located at the tip side of the cutting torch 11 has a nozzle 16 attached via a nozzle receiver 51 (Fig. 8). A plurality of supply hoses 18 are connected to the base end side of the cutting torch 11. As shown in Figs. 3 and 4, the tip side of the cutting torch 11 is provided with various pipes, such as a fuel gas supply pipe 20, a cutting oxygen supply pipe 21a, a preheating oxygen supply pipe 21b, a metal powder (also called "metal powder", hereinafter referred to as "powder") supply pipe 22, and a cooling water supply pipe 23.

[0013] 2, each supply hose 18 is connected to the fuel gas supply pipe 20, the cutting oxygen supply pipe 21a, the preheating oxygen supply pipe 21b, the powder supply pipe 22, and the cooling water supply pipe 23 at the base end side of the cutting torch 11. The cooling water supply pipe 23 has an outward (for outward path (IN)) and a return (for return path (OUT)).

[0014] The cooling water supply pipe 23 circulates cooling water (not shown) inside the cutting torch 11. Furthermore, the cooling water supply pipe 23 has a portion (hereinafter referred to as "cooling water IN") 23a that guides the cooling water toward the nozzle 16, and a portion (hereinafter referred to as "cooling water OUT") 23b that guides the cooling water that has cooled the nozzle 16 toward the outside of the cutting torch 11.

[0015] The nozzle 16 is attached to the tip of the cutting torch 11 as shown in Fig. 2. The nozzle 16 has an outer nozzle 25, an intermediate outer portion 26, an inner tube 27, an inner core rod 28, and a stop blank 29 as shown in Fig. 5. Five passages are formed inside the nozzle 16, and each passage is assigned to a fuel gas supply pipe 20, a cutting oxygen supply pipe 21a, a preheating oxygen supply pipe 21b, a powder supply pipe 22, and a cooling water supply pipe 23 (cooling water IN 23a, cooling water OUT 23b).

[0016] The nozzle 16 is detachably attached to the tip side of the main body 14 via a nozzle receiver 51 (FIG. 8, described later). The nozzle 16 has a tapered shape that narrows from the tip side (the side that faces the tip side of the main body 14 when attached to the main body 14) to the base side. The inner wall of the main body 14 is also machined to have a tapered shape that narrows from the tip side to the base side, and the nozzle 16 is fitted into the inner wall of the nozzle receiver 51 (FIG. 8, described later).

[0017] The nozzle 16 also has openings connected to a fuel gas supply pipe 20, a cutting oxygen supply pipe 21a, a preheating oxygen supply pipe 21b, and a powder supply pipe 22. Of these, the opening for cutting oxygen, the opening for preheating oxygen, and the opening for powder (metal powder, metal powder) are concentrically arranged with the opening for fuel gas at the center.

[0018] As the nozzle receiver 51, those shown in Figures 8(a) to (d) can be used. In the nozzle receiver 51 shown in Figures 8(a) to (d), a cutting oxygen passage hole for passing cutting oxygen, a preheating oxygen passage hole for passing preheating oxygen, and a powder passage hole for passing powder are opened on the outer circumferential surface 52 and the base end surface 53. The nozzle receiver 51 takes in the cutting oxygen, preheating oxygen, and powder from the side opposite the base end surface 53 (the surface on the tip side) and ejects them together with fuel gas.

[0019] 1, supply hose 18 is connected to cutting torch 11 and adjustment device 12. Although not shown, containers (cylinders, tanks, etc.) that contain fuel gas, oxygen, powder, and cooling water are installed in adjustment device 12. Each supply hose 18 is made of a material such as rubber or resin that can supply fuel gas, oxygen, powder, and cooling water to cutting torch 11, respectively.

[0020] The fuel gas may be hydrogen gas or various other gases, but is preferably hydrogen-rich gas, such as hydrogen gas (100%) or a mixture of hydrogen gas and a carbon-based gas (with a hydrogen mixing ratio of 50% or more).

[0021] When hydrogen-rich gas is used, it is possible to suppress the radiant heat from the workpiece during cutting. In addition, hydrogen-rich gas has excellent linearity when sprayed. This makes it possible to suppress the temperature felt by the worker and overheating of the cutting torch 11. Furthermore, the flame can be sprayed accurately toward the desired location.

[0022] The cutting oxygen supplied to the cutting torch 11 has the function of burning the powder and discharging the molten reinforced concrete. The powder has the function of raising the temperature of the flame. A mixed powder of iron and aluminum is used as the powder. When aluminum is mixed, the object is melted by utilizing the heat generated by oxidation of the aluminum. At this time, iron oxide is used as a base to assist fluidity, and a powder with a high heat of oxidation reaction (aluminum in this case) is mixed to improve the cutting ability. However, this is not limited to this, and various powders that can raise the temperature of the flame to a required temperature or higher can be adopted. By changing the mixture ratio depending on the configuration (characteristics such as structure and composition) of the object to be cut (structure 32 described later in this case), the fluidity of the heated and melted structure (molten material) can be improved and the dischargeability can be improved.

[0023] The powder may be only iron or only aluminum. The powder may contain magnesium or the like, either mixed with other metal powders or used alone. The powder may be a mixture of iron and other metal powders, and the iron mixing ratio (also called the "mixing ratio" or "mixing proportion") in the powder may be relatively high (more than 50%). The iron mixing ratio may be, for example, 65 to 90% (weight %). The iron mixing ratio may be changed (determined) in consideration of the worker's condition (working posture, work content, etc.).

[0024] At least some of the metal powder particles constituting the powder have a size that is visible (also called "particle size" or "diameter"). This makes it possible to make the mixed gas visible even if other components of the mixed gas (fuel gas such as hydrogen gas and various types of oxygen) are not visible. Then, the mixed gas can be ignited after visually checking the injection state of the mixed gas (speed, flow rate, straightness, etc.).

[0025] 6 illustrates an example of a worker 30 holding and operating the cutting torch 11 to cut a structure 32 made of reinforced concrete or the like. When cutting the structure 32, fuel gas and preheated oxygen supplied to the cutting torch 11 are sprayed from the cutting torch 11 at high pressure. Powder sprayed from the cutting torch 11 is mixed with the mixed gas of the fuel gas and preheated oxygen, and this mixed gas (mixture) is ignited. More specifically, it is considered that the powder is heated by the mixed gas, and ignited by the cutting oxygen.

[0026] A flame 34 is ejected from the cutting torch 11 so as to travel in a straight line. Fig. 6 shows a schematic diagram of the flame 34 reflecting off the structure 32. An operator 30 faces the tip of the cutting torch 11 toward the structure 32 and heats the surface of the structure 32. Furthermore, when the preheating stage is completed, cutting oxygen is added to the preheating oxygen to maintain (or intensify) the flame 34. Then, by supplying cutting oxygen and powder, the high-temperature flame 34 is ejected and the structure 32 is heated.

[0027] After the cutting oxygen is supplied, the cutting temperature of the flame 34 reaches 2000 to 2500°C or higher due to the action of the mixed powder, exceeding the melting point of the structure. Then, the high-temperature flame 34 is blown onto the structure 32, and the part of the structure 32 that the flame 34 hits melts.

[0028] In the structure 32, a cracking section 36 (FIG. 7) is formed by partially removing concrete and reinforcing bars by the flame 34. As the cracking section 36 is formed, the molten structure (molten material) flows out. For example, the worker 30 gradually advances the tip side of the cutting torch 11 into the cracking section 36, deepening the cracking section 36. FIG. 7 shows a schematic view of the tip side of the cutting torch 11 entering the cracking section 36.

[0029] The worker 30 moves the cutting torch 11 forward and in a suitable combination of horizontal and vertical movements. The worker 30 then cuts out the structure 32 one by one into, for example, a plate or rectangular parallelepiped shape, and proceeds with the demolition of a building or the like made of reinforced concrete. Cooling water flows through the cutting torch 11 via the cooling water supply pipe 23, and this cooling water circulates between the inside and outside of the cutting torch 11. This prevents the cutting torch 11 from excessively increasing in temperature during cutting work.

[0030] In such cutting work, exhaust gas containing dust is generated due to the ejection of flame 34 and melting of reinforced concrete (structure 32). The generated exhaust dust is collected by dust collector 13 together with the exhaust air. As shown in a schematic diagram in Fig. 1, dust collector 13 is composed of a chamber section 41 that covers the work position, a transport section 42 having one end connected to chamber section 41, and a dust collector (dust collection section) 43 having the other end connected to transport section 42.

[0031] The chamber 41 has, for example, a rectangular parallelepiped shape and surrounds a work area where cutting work is performed. The chamber 41 is formed using a fire-resistant material (such as a metal material). The chamber 41 can be in various shapes as long as it can exhibit a shielding function to prevent gas and sparks from scattering when the mixed gas is burned. For example, the chamber 41 can be in various shapes such as a box shape, an enclosure shape, a dome shape, a polygonal shape, and an irregular shape. As shown in FIG. 1, the worker 30 stands outside the chamber 41. The worker 30 inserts the tip side of the cutting torch 11 into the work side opening 45 formed in the chamber 41 and performs the cutting work as described above.

[0032] When the working side opening 45 is, for example, rectangular in shape, it is possible to move the cutting torch 11 linearly in the horizontal or vertical direction using the edge of the working side opening 45 as a guide. That is, for example, a part of the portion between the tip side of the cutting torch 11 and the worker 30 is placed on the lower edge of the working side opening 45, and the worker moves the cutting torch 11 while keeping it in contact with the lower edge of the working side opening 45. Then, the cutting torch 11 moves along the shape of the lower edge of the working side opening 45, and the structure 32 is cut linearly.

[0033] Here, in the above-mentioned Figures 6 and 7, the chamber section 41 is omitted so as not to clutter the drawings, but even in the cutting operation illustrated in Figures 6 and 7, the working area is surrounded by the chamber section 41.

[0034] Although not shown, the chamber section 41 may be supported by a lifting mechanism (such as a crane or winch) so that it can be raised and lowered. In this way, it is possible to change the height of the work side opening 45 and change the reach of the cutting torch 11.

[0035] 6 and 7 show a shielding metal plate 48. This shielding metal plate 48 is formed into a plate shape using a fire-resistant metal material. The shielding metal plate 48 can be used by the worker 30 alone or in combination with the chamber section 41 as necessary to prevent radiant heat and sparks. A rectangular opening 49 is provided in the shielding metal plate 48, and the edge of this opening 49 can also be used as a guide for the cutting torch 11, similar to the working side opening 45 of the chamber section 41.

[0036] An exhaust side opening 46 is formed in the chamber 41, and a tubular transport section 42 is airtightly connected to this exhaust side opening 46. The internal space of the chamber 41 is connected to the dust collector 43 via the transport section 42, and when the dust collector 43 starts a dust collection operation, the air inside the chamber 41 is sucked into the dust collector 43 via the transport section 42. The dust collector 43 filters (stills) dust from the air sucked in through the transport section 42 using a filter, and exhausts the purified air. As the dust collector 43, various general types can be used.

[0037] Since the air in the chamber 41 is sucked by the dust collector 43, the air pressure in the chamber 41 becomes negative. Therefore, it is possible to prevent the dust generated in the chamber 41 from flowing back from the work side opening 45. It is also possible to prevent the sparks generated inside the chamber 41 from bouncing back to the worker 30. Here, the dust collector 43 has a performance capable of generating an air velocity (wind speed) from the outside to the inside of the chamber 41 at the work side opening 45. Furthermore, the dust collector 43 has a function of automatically impacting the filter at a constant period, for example, to automatically brush off the dust adhering to the filter. In order to impact the filter, it is possible to blow compressed air intermittently (in a pulsed manner) to the filter. It is also possible to support the filter by a mechanical displacement mechanism and to intermittently shake it.

[0038] For example, a flexible duct having flexibility is adopted as the transport section 42. The length of the transport section 42 is, for example, several meters to several tens of meters. This is to ensure a sufficient length of the transport section 42 and to sufficiently reduce the temperature of the high-temperature air (exhaust air containing dust) discharged from the chamber section 41 before it reaches the dust collector 43. By using a flexible duct for the transport section 42, the transport section 42 can be installed at the work site in a meandering or wound state, making it possible to cool the exhaust air in a space-saving manner.

[0039] According to the cutting device 10 and the cutting method performed using the cutting device 10 as described above, the cutting torch 11 only contains various pipes (such as the fuel gas supply pipe 20 and the cutting oxygen supply pipe 21a), the nozzle 16, and the nozzle receiver 51, and the cutting torch 11 is small and lightweight. Furthermore, cooling water flows and circulates inside the cutting torch 11. This allows an operator to mobilize cutting work while holding the cutting torch 11 in his or her hand.

[0040] Although the cutting torch 11 can be held by the worker 30, the support of the cutting torch 11 is not necessarily limited to being held by the worker 30. For example, it is possible to provide a holding device (not shown) for the cutting torch 11 and support the cutting torch 11 by this holding device. Examples of holding devices include relatively lightweight simple types (holder types, stand types, handle types, etc.) and heavy machinery attachments that can be attached to heavy machinery.

[0041] In addition, it is possible to locate the reinforcing bars in advance, and to mark the positions of the reinforcing bars with marks, etc. In this way, it becomes easier for the worker 30 to identify the cutting positions, shortening the work time and improving the cutting efficiency.

[0042] Moreover, according to the cutting device 10 and cutting method of the present embodiment, it is possible to simultaneously cut the concrete and steel that constitute a reinforced concrete structure with the high-temperature flame 34. And because it is gas cutting, it is possible to perform cutting with low vibration without generating vibrations that may affect the surrounding environment. Furthermore, it is possible to perform efficient cutting in a short time even for structures that have a relatively large amount of steel.

[0043] Furthermore, according to the cutting device 10 and cutting method of the present embodiment, the periphery of the work area is surrounded by the chamber 41, so that the noise generated by cutting can be reduced. Therefore, the cutting device and cutting method using mixed gas can further reduce the impact on the environment.

[0044] Furthermore, according to the cutting device 10 and cutting method of this embodiment, the periphery of the work area is surrounded by the chamber section 41, and dust generated in the exhaust is collected by the dust collector 43, which further reduces the impact on the environment. Also, for the worker, dust can be prevented from floating around the worker, improving the working environment.

[0045] In the cutting device 10 and cutting method of this embodiment, hydrogen-based mixed gas and powder (metal powder) are burned, so that dust, carbon monoxide (hereinafter referred to as "CO"), and carbon dioxide (hereinafter referred to as "CO2") are generated. As an example, when the dust concentration in the chamber 41 and the dust concentration at the exhaust port (outlet) of the dust collector 43 were measured and compared, the dust concentration in the chamber 41 was 502 mg / m 3 whereas the dust concentration at the outlet of the dust collector 43 was 1.8 mg / m 3 The dust collector 43 used had an outlet (exhaust port) at a height of about 3 m.

[0046] It is difficult to accurately measure the dust concentration after diffusion during gas cutting because the measurement of the dust concentration after diffusion is affected by wind speed and direction, atmospheric stability, and surrounding environmental conditions. Therefore, the dust concentration at the outlet of the 3m-high dust collector 43 used for the measurement was 1.8 mg / m 3 The dust concentration at a height of 1.5 m when the dust was dispersed was estimated by the plume method. The estimation conditions were wind speed of 5 m / s and 6 m / s, and atmospheric stability of C. The dust supply amount per unit time was calculated from the dust concentration and gas temperature at the outlet of the dust collector 43, and the flow rate of the dust collector 43, and was set to 2.1 mg / s.

[0047] The estimated dust concentration is 0.37×10 -3 mg / m 3 This estimated value is the maximum value, so in reality, the value is 0.1 mg / m3 (100 x 10 -3 mg / m 3) It is considered that the

[0048] Next, regarding CO, when the dust collector 43 is in operation, it is possible to reduce the concentration of CO by mixing with the entrained air and disperse it. The measured flow rate of the dust collector 43 is 56.4 Nm 3 / min(Nm 3 The volume of gas generated during gas cutting, estimated from the amount of fuel used, was 3.4 Nm 3 / min, the CO concentration generated by gas cutting is expected to be reduced to 1 / 16.5. The reference value for CO2 is expected to be 0.17%.

[0049] In addition, by adopting such a cutting method as a pre-treatment of a highly quiet demolition method, the highly quiet method can be continuously performed. An example of a subsequent highly quiet method is a method (electric heating crushing method) in which a high power (particularly a current) such as DC2500A-50V (rated) is supplied to the reinforcing bar exposed from the concrete to heat the reinforcing bar. In such a method, the reinforcing bar expands and cracks occur in the concrete, reducing the concrete strength (weakening the concrete) and reducing the adhesive force between the reinforcing bar and the concrete. Therefore, in the subsequent demolition (such as demolition of heavy machinery using a crusher or giant breaker), work can be performed efficiently with relatively small force. In addition, demolition can be performed with low noise, low vibration, in a short time, and with low dust, and the impact on the surrounding environment is small. As described above, the highly quiet method can be continuously performed to consistently perform the cutting to demolition of the structure 32. In addition, it is possible to perform the cutting to demolition of the structure 32 with further reduced impact on the environment.

[0050] As described above, when cutting the structure 32, the structure 32 melts (heat-melts) due to heating, generating a molten material. In gas cutting with the cutting torch 11, a mixed gas containing iron powder and aluminum powder is used to simultaneously cut the reinforcing steel and concrete, and the molten material generated is a mixture of molten iron, aluminum, their metal oxides, and concrete, and is molten concrete containing metal elements. This molten concrete flows down from the cracked portion 36 toward the ground or splashes toward the worker 30. Furthermore, the molten concrete cools when it comes into contact with the air while flowing down from the cracked portion 36 (or drooping) or while adhering to the cut surface (such as the cracked portion 36).

[0051] When the molten concrete is cooled to a certain temperature, it solidifies and becomes a solid. The solidified molten concrete is separated from the structure 32 and can be called a "separate solidified material". Since the separated solidified material contains metal elements, it has a heavier specific gravity than concrete alone. This separated solidified material can be reused as fire-resistant aggregate. Possible uses for the separated solidified material include cutting it into a rectangular shape and using it like a brick, or making it into an ornamental piece that takes advantage of its amorphous shape when it solidifies.

[0052] In addition, various objects can be used as the cutting object (structure 32) other than reinforced concrete. For example, the cutting object can be an object made of acrylic resin glass, a gas tank, or a soil column wall (an H-shaped steel embedded in cement-mixed soil as a core material). In addition, the cutting object can be an object at a construction site, an object at a demolition site, or a structure other than a structure containing iron.

[0053] Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and many modifications are possible within the scope of the technical idea of ​​the present invention. The embodiment described is merely one example of a specific embodiment for carrying out the present invention, and the technical scope of the present invention should not be interpreted as being limited thereto. [Explanation of symbols]

[0054] 10 Cutting device 11 Cutting torch 12 Adjustment device 13 Dust collector 14 Main body 15 Flame mouth 16 Crater 18 Supply Hose 20 Fuel gas supply pipe 21a Cutting oxygen supply pipe 21b Preheating oxygen supply pipe 22 Powder supply pipe 23 Cooling water supply pipe 25 External Crater 26 Intermediate External 27 Inner tube 28 Internal core rod 29 Winning Blank 30 Workers 32 Structures 34 Flame 36 Dehiscence 41 Chamber section 42 Transportation Department 43 Dust collector (dust collection section) 45 Working side opening 46 Exhaust side opening 51 Fire Nozzle 52 Outer surface 53 Proximal surface

Claims

1. A cutting torch that can be held by hand and used to cut an object to be cut; a supply hose for supplying at least fuel gas and powder to the cutting torch; a dust collecting device capable of sucking in both exhaust gas and dust generated by cutting the object to be cut; and a chamber portion surrounding at least a portion of the object to be cut by the cutting torch, the chamber portion having a work side opening into which the cutting torch can be inserted and which guides the cutting torch movably.

2. The dust collecting device includes: A dust collection unit that collects dust; 2. The apparatus for cutting an object according to claim 1, further comprising: a transport section for transporting both the exhaust gas and the dust from the chamber section to the dust recovery section.

3. The cutting device for an object to be cut according to claim 2 , wherein the transport section is flexible and connects the chamber section and the dust collection section.

4. The dust collecting device includes:

2. The apparatus for cutting an object according to claim 1, further comprising a filter section for filtering out dust sucked in together with exhaust air and discharging purified air.

5. 3. The apparatus for cutting an object according to claim 2, wherein the chamber portion is fire-resistant.

6. 6. The apparatus for cutting an object according to claim 1, wherein the combustion of the fuel gas, which is invisible, is made visible by adding the powder.

7. A cutting torch that can be held by hand and used to cut an object to be cut; a supply hose for supplying at least fuel gas and powder to the cutting torch; A dust collecting device capable of collecting dust generated by cutting the object to be cut; A method for cutting an object to be cut using a cutting device including: a chamber portion surrounding at least a portion of the object to be cut by the cutting torch, the chamber portion having a work-side opening into which the cutting torch can be inserted and which guides the cutting torch movably, The cutting torch is used while being held by hand, A method for cutting a structure, comprising cutting the object while sucking in dust generated by cutting the object together with exhaust gas using the dust collecting device.

8. 6. The apparatus for cutting an object according to claim 1, wherein the powder is mixed with iron powder at a ratio of 50 to 90% (by weight).

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