JP5138196B2 - Asbestos removal method - Google Patents

Description

  The present invention relates to an asbestos removal method for removing an asbestos-containing material layer formed on a structure wall surface, and a suction blast device suitable for the method. Here, the structure wall surface is a broad concept including all wall surfaces in a building, a workpiece, a structure, or the like that may be constructed with an asbestos-containing material layer. Specifically, the walls of buildings / ships, tunnels, trenches, and the walls of chimneys, pipes, ducts, boilers and other chemical facilities (plants) in factories and ships can be mentioned.

  Asbestos (asbestos) is, in principle, prohibited from being manufactured and used because it is carcinogenic to the respiratory system (lung cancer and malignant mesothelioma).

  On the other hand, asbestos does not rot, has heat resistance and chemical resistance, and is lightweight, so it has been frequently used as a building material together with industrial materials. Especially as a raw material for building materials such as asbestos board, slate, tile, etc., and as a raw material for blowing materials (fillers) for preventing fire, heat insulation, sound absorption and condensation on pillars, beams, ceilings and piping ducts. Have been used.

  And as for the removal of the asbestos-containing material layer formed by spraying or the like, conventionally, scraping has been the mainstream. The scraping work is in principle manual work using a scraper (keren rod or spatula) or metal brush (wire brush). If removal quality is difficult to ensure by manual work, an electric tool (electric grinder) may be used. It was.

  As described above, the shaving work was very hard work and labor-intensive.

  Since it is not desirable if asbestos remains on the finished surface, it is usually finished by sandpaper or the like (60 to 80% of man-hour required for removal main work excluding preparation and post-cleaning is required) or by chemicals I was doing asbestos containment. In the latter case, asbestos measures will be required again when the building is finally removed.

  Furthermore, regarding asbestos removal, the occupational safety and health law, asbestos injury prevention regulations, the air pollution prevention law, etc. are designed to ensure safety for those who perform the removal work and for those around the removal work.

  For example, Article 6 of the Asbestos Obstruction Prevention Regulations states that “the employer shall be engaged in work to remove asbestos, etc. when dismantling buildings with asbestos sprayed on walls, pillars, ceilings, etc. When the worker is engaged, the work place where the removal is performed must be isolated from the work place where the other work is performed. ”According to the Air Pollution Control Law, ”Provide a front chamber at the entrance and exit of the factory.

  For this reason, various methods for mechanically removing the asbestos-containing material layer have been proposed.

  For example, as publications describing a method of removing using blasting (abrasive projection) related to the present invention, there are Patent Documents 1, 2, 3 and the like. These are not intended to eliminate the remaining asbestos on the finished surface after the asbestos removal, and do not affect the patentability of the present invention.

  Patent Document 1 describes a method for removing an asbestos material having the following configuration (see claims and the like).

“The wear-resistant material brush attached to the suction inner cylinder in the holder was pressed against the asbestos material, and sand was applied with high-pressure air from the nozzle in the suction inner cylinder through the center of the wear-resistant material brush. Injected into asbestos material, peels off the asbestos material, sucks the separated asbestos material and sand sprayed from the nozzle into the cyclone and separates it into asbestos material and sand, and then separates the asbestos material into the recovery tank When sucking and collecting, the asbestos material scattered from the wear-resistant brush to the periphery thereof is sucked and collected from between the suction inner cylinder and the surrounding holder to the collecting tank, and the collecting tank The asbestos removal method is characterized by opening the discharge valve provided at the outlet of the tank and taking out the asbestos material in the collection tank into a storage container that is detachably attached to the outlet. . "
Patent Document 2 describes a method for removing sprayed asbestos having the following configuration.

"The asbestos layer deposited by spraying on the surface of the skeleton is centrifugally projected with a rotating impeller at a projection speed of 55-70 mm / sec. A method for removing sprayed asbestos, characterized in that the asbestos layer is removed from the housing surface. "
Patent Document 3 describes a method for removing sprayed asbestos having the following configuration.

“Small plastic resin particles with a particle size of 0.8 to 3.0 mm are centrifugally projected with a rotating impeller at a projection speed of 55 to 70 mm / sec. The removal method of sprayed asbestos characterized by removing from the housing surface. "
Further, as publications disclosing a method for removing asbestos by mechanical cutting without using blasting (abrasive projection), there are Patent Documents 4 and 5 and the like.
Japanese Patent Publication No. 4-53233 (claims, etc.) Japanese Patent Publication No. 7-57467 (Claims) Japanese Patent No. 2533364 (Claims etc.) JP-A-3-51480 (Claims etc.) JP-A-3-51481 (Claims etc.)

  It is an object of the present invention to provide a method for removing asbestos having a novel configuration that makes it practically possible (becomes easy) not to leave asbestos on the groundwork after asbestos removal.

  As a result of diligent development in order to solve the above problems, the present inventors have made an asbestos-containing material layer, which is a work surface, manually or manually by a scraping blade (scraper), a wire brush, a grinder, or the like. We found that a surface with virtually no residual asbestos can be formed by simultaneously sucking and collecting the dust generated by projecting (injecting) the abrasive onto the work surface that has been scraped off manually by the machine. I came up with an asbestos removal method.

A method for removing an asbestos-containing material layer formed on a wall of a structure using a suction blasting device equipped with a projection suction gun,
A scraping step of scraping off the asbestos-containing material layer on the work surface to be subjected to the method, and a blasting step of projecting an abrasive on the work surface after the scraping step,
The projection suction gun includes a projection nozzle and a suction cover body, and the suction cover body is formed of a bristle brush that forms a hermetic space when the entire circumference or a partial circumference of the tip periphery is pressed against the work surface. ,
In the blasting process, while pressing the bristle brush against the work surface, the abrasive material is projected onto the work surface by air pressure at the inner position of the brush, and at the same time, the generated dust is sucked together with the abrasive material. ,
With the bristle brush , the dust generated on the work surface or the surface deposits that are easily peeled off are collected, and the amount of air for suction in the projection suction gun is 2 to 30 times the amount of air for projection. As described above, an air flow from the outer periphery of the bristle brush toward the inside is generated by the suction action of the projection suction gun.

  After scraping off (cutting and peeling) by manual work, etc., the abrasive material is projected, and the work surface after the scraping process is blasted (projected) with the abrasive material, resulting in a residual asbestos-containing material layer (attachment containing asbestos) Residue: scale) is removed.

  In other words, the asbestos-containing material layer in a thin layer or a scattered state is formed on the asbestos-containing material layer, which is relatively harder than the asbestos-containing material layer, and the thinned asbestos-containing material layer collides at high speed. It is pulverized so that it can be easily peeled off or peeled off. By scraping with a bristle brush while sucking in this state, it is recovered as dust containing asbestos, and the asbestos-containing dust is not scattered in the working chamber.

  Further, it is not necessary to completely scrape off the asbestos-containing material layer, which is a normal manual operation. That is, roughing (rough removal) is sufficient for scraping off by hand work or the like.

  In this way, it is possible to form a work-finished wall surface (base surface) having no residual asbestos in a short time, and it is possible to reduce the man-hour for asbestos removal work as a whole.

  If the asbestos-containing material layer is to be removed by sandblasting from the beginning, the removal work efficiency as a whole decreases.

  If the asbestos-containing material layer is thick, it will hinder removal and recovery. This is because the initial projection material may be embedded in the asbestos-containing material layer, a large amount of dust is collected by blasting, and the replacement of the dust bag may occur frequently. In addition, the proportion of powdered asbestos-containing material layers in the sucked dust increases, which may cause clogging of the circulating projection material in the blasting device depending on the moisture contained in the asbestos-containing material layer. Connected.

  When the asbestos-containing material layer is relatively thin, only the blasting process may be performed. However, for the same reason as when the asbestos-containing material layer is thick, although it is not as much as when the asbestos-containing material layer is thick, there is a possibility that the time required for removing asbestos may become long as a result.

The blasting process,
1) Abrasive material from a projection suction gun comprising a projection nozzle and a suction cover body formed with a bristle brush on the entire circumference or a partial circumference of the tip periphery that forms a sealed space when pressed against the wall surface. Project,
2) The dust generated by the projection of the abrasive is sucked together with the abrasive and separated into the abrasive and the dust by a separator.
3) The polishing material is returned to the pressurized tank connected to the projection nozzle and circulated for use, and the dust is removed and collected by a dust collector.
These steps can be included.

  Here, the entire circumference or partial circumference of the tip of the suction cover body of the projection / suction gun is formed with a bristle brush. The suction cover body is not in close contact with the operation surface, and the wall surface operability (mobility) of the gun In addition, the dust generated by the sharpening action of the bristle brush by sucking air through the bristle brush is also removed by the air flow (especially when the entire circumference or more than half is formed by the bristle brush). Cleanability of the wall after being sucked into the interior and projected is improved. When the outer periphery of the suction port is formed of sponge rubber as in Patent Document 1, the inside is likely to be in a high vacuum, the wall surface operability (mobility) of the gun may be hindered, and a substantial air flow It does not occur in the outer periphery of the suction port, and the area of the cleaning action generating surface accompanying the movement of the gun is also relatively smaller than in the case of the present invention.

  In each of the above configurations, the scraping step can be performed with the work surface wetted, and the blasting step can be performed with the work surface being in a lower wet or dry state than in the scraping step.

  Dust generation can be suppressed by performing the scraping process in a wet state, and blasting efficiency can be improved by performing the blasting process in a dry state. Clogging is less likely to occur.

  When the asbestos-containing material layer to which the present invention is applied is solidified by a containment process, the effect becomes remarkable.

  The solidified asbestos-containing material layer has excellent adhesion to the surface of the structure (wall surface), so removal by hand alone is inefficient, the finishing accuracy of the removal is low, and dust scattering Therefore, it is possible to provide a method with high finishing accuracy for removal.

  In each of the above-described configurations, it is desirable to perform the blasting operation by selecting the type and hardness of the polishing material in accordance with the material of the base of the structure wall and the required finishing degree.

  It is possible to obtain a wall surface that does not require a finishing process on the wall surface after the asbestos removal or is suitable for the finishing process.

  In each of the above configurations, the amount of air for suction in the projection suction gun is preferably 2 to 30 times, more preferably 5 to 20 times the amount of air for projection. In cooperation with the configuration in which the tip peripheral edge of the suction cover body is formed of a bristle brush, it becomes easy to maintain the negative pressure in the workplace.

  In each of the above-described configurations, the work surface after the blasting process can be further cleaned by only the suction action without projecting the projection material using the projection suction gun. The same device can be used, and there is no need to prepare a vacuum cleaner or the like having a high-performance filter function.

  Examples of the suction blasting apparatus that can be used in the asbestos removal method of the present invention include the following ones.

A suction blasting device,
1) a projection nozzle capable of projecting a polishing material by air pressure, and a suction cover body formed with a bristle brush on the entire circumference or a partial circumference of the tip periphery that forms a sealed space when pressed against a wall surface (work surface) A projection suction gun with
2) a separator connected to the projection suction gun via a suction hose;
3) A polishing material inlet into which the polishing material separated by the separator flows, and a pressurized tank having a polishing material mixing section connected via the projection nozzle and the projection hose,
4) a dust collector connected to the dust discharge port of the separator,
The bristle brush collects dust generated on the work surface or surface deposits that are easily peeled off, and generates an air flow from the outer periphery of the bristle brush toward the inside by the suction action of the projection suction gun. It is characterized by being.

  The suction blast device having the above-described configuration may be configured such that the separator, the pressurized tank, and the dust collecting device are installed on a carriage and can be moved integrally.

  By integrating on the carriage, the work carried into the work site becomes easy. This is because a short projection hose or suction hose is sufficient.

  The present invention relates to an asbestos removal method for removing an asbestos-containing material layer formed on a wall surface of a structure.

  Here, the material of the structure wall surface (base wall surface) on which the asbestos-containing structural material layer to be removed is formed is not particularly limited as long as it has a strength that can withstand the blasting process. Reinforced concrete (RC), steel material ( H-shaped steel, I-shaped steel, square steel, steel pipe, etc.), steel plate (iron plate) and other metal plates (aluminum plate), gypsum board, plywood, plastic plate and the like. However, from the viewpoint of the blasting effect in the blasting process (the effect of crushing and removing the asbestos thin layer, etc.), reinforced concrete, steel, etc. with high surface hardness are desirable.

  The asbestos-containing material layer to be applied is not particularly limited as long as it contains asbestos, and includes any coating layer and adhesive layer. Usually, a spray layer such as a surface spray layer or a base adjustment spray layer is used. It also includes those in which the asbestos-containing material layer is sealed with a chemical (solidifying agent) after roughing or without roughing.

  The removal method of the present invention basically comprises the following scraping step (1) and blasting step (2).

  Naturally, when performing the removal operation, it is necessary to perform a curing treatment on the floor and the wall surface, to perform a sealing / covering treatment to prevent scattering to the outside, and to make the work place have a negative pressure.

  (1) Scraping step (pre-removal step): This is a step of scraping off the asbestos-containing material layer on the work surface to be subjected to the asbestos removal method of the present invention with a scraping blade (scraper), a bristle brush, a grinder or the like.

  Here, examples of the scraping blade include a spatula and a stick rod. Further, scraping is usually performed manually, but an electric grinder or a hand-held cutting tool as described in Patent Documents 4 and 5 (see FIGS. 2 to 4 of Patent Document 4) is used. A semi-powered handmade work may be used.

This scraping step is usually performed by wetting with a wetting agent (medicine), water spray or the like. Level of wetting, with water spray quantity, 0.5~2.0kg / m ² relative to the thickness 10 mm, preferably a 0.8~1.2kg / m ^2.

  In the scraping step, the asbestos-containing material layer may be thinned (rough cutting may be performed) until the blasting effect in the subsequent step (the blasting effect by blasting) can be ensured.

  Here, the thickness of the thin layer is usually 1 to 2 mm or less. Incidentally, the thickness of the asbestos-containing material layer (in the case of sprayed asbestos) is usually in the range of 3 to 60 mm. Therefore, if the asbestos-containing material layer before removal (treatment) is less than the above thickness, it may be said that the scraping process is unnecessary, but by adding the scraping process, the man-hour for removal finishing by the subsequent blasting process is reduced. Can be performed smoothly.

  (2) Blasting step (removal finishing step): A step of rubbing with a bristle brush while projecting (blasting / blasting) the abrasive onto the work surface, and further sucking the generated dust together with the abrasive.

  Here, the material of the polishing material (projection material / blasting material) depends on the base material, but alumina, other metal oxides, slag, steel (cast steel), plastic, baking soda (sodium hydrogen carbonate), other inorganic compounds, and even plants Seeds and the like can be used as appropriate.

  The shape of the abrasive is classified into a spherical shape, a grit (polygonal shape), etc., but is not particularly limited.

  In addition, it is desirable to select the type and hardness of the abrasive according to the material of the foundation of the structure wall and the required finish (particularly, the asbestos-containing material layer is formed on the inner wall side of the structure wall. In case it is). It is possible to obtain a wall surface free from scratches or distortion suitable for the post-finishing process because the post-finishing process on the inner wall on the indoor side after asbestos removal is unnecessary.

  By using a polishing material having a hardness equal to or lower than that of the underlying wall surface, a wall surface without scratches or distortion can be easily obtained. It is also possible to obtain a wall without scratches or distortion by using a polishing material whose hardness exceeds that of the underlying wall and adjusting the projection (blast) time, pressure, and amount. However, the removal work efficiency is deteriorated and is not practical.

  The average diameter of the projection material is appropriately selected from the range of, for example, an average particle diameter of 0.1 to 2.5 mm, desirably 0.3 to 1.2 mm. However, the range of the average diameter varies depending on the characteristics (thickness / material) of the asbestos-containing material layer, the material / hardness of the base, the type of the projection material, and the like, and is not absolute.

  The blasting conditions depend on the material, size (particle size) and shape of the polishing material, and the required finishing mode of the base material, but the air (projection) pressure is in the range of 0.1 to 1.0 MPa, preferably 0.2 to 0.7 MPa. Select as appropriate.

Further, the projection amount (kg / m ² ) necessary for removing asbestos varies depending on the type of the projection material and the material, characteristics, and thickness of the asbestos-containing material layer. For example, in the case of steel grit, the projection amount is 40 to 120 kg / m ² .

  The blasting process specifically includes the following processes. A description will be given mainly with reference to FIG. 1 in the case of using a suction blast device mounted on a truck bed.

  1) Abrasive material is projected (injected / blasted) from the projection suction gun 11 onto the surface of the asbestos-containing material layer.

  Here, the configuration of the projection suction gun 11 includes a suction cover in which the peripheral edge of the suction cover body that forms a sealed space when pressed against the wall surface W is formed by a bristle brush 15 as shown in the figure. And a body 17. In the illustrated example, the entire periphery of the tip periphery of the suction cover body is formed by a bristle brush. However, a partial periphery (usually half or more) of the tip periphery of the suction cover body is a bristle brush, and the other part is a soft member (for example, a sponge). It may be formed of rubber or wear-resistant rubber.

  Here, although the bristle brush 15 may be a wire brush (steel wire), it may be made of a hard plastic such as a polyamide / polyester.

  The wire diameter and length of the bristle brush are, for example, 0.3 to 0.8 mmφ and 30 to 100 mm in the case of a nylon brush.

  The bristle brush collects dust generated on the surface to be treated or scrapes surface deposits that have been easily peeled off, and generates an air flow from the outer periphery of the brush to the inside due to the suction action of the gun. While preventing the deposits from scattering to the outside, it is easy to maintain a negative pressure in the workplace, and further increase the cleaning surface.

  The projection nozzle 13 is connected to a polishing material mixing portion 19 a of the pressurized tank 19 and a projection hose (blast hose) 22. Note that a flow rate adjusting valve (not shown) is attached to the polishing material mixing portion 19a.

  In addition, 21 is an air piping for the air inflow to the pressurization tank 19 and the projection hose 22, and is connected with the compressor (not shown).

  2) Dust generated by the projection of the abrasive is sucked together with the abrasive, and separated into the abrasive and dust by the separator 23.

  That is, the suction connection port 17 a on the outer peripheral portion of the suction cover body 17 is connected to the raw material inlet (suction port) 23 a of the separator 23 via the suction hose (vacuum hose) 25.

Configuration here separator 23 can be a cyclonic if separated into abrasive cleaning agent and dust, but in this embodiment, are the following configurations in combination an air classifier and (air elutriation) and vibrating sieve.

  A horizontal vibration sieve 29 is disposed in the separator body 27, and a flow rate adjusting damper 31 for air classification is disposed on the raw material inlet 19 a side directly above the vibration sieve 29.

  The flow rate adjustment damper 31 adjusts and fixes the inclination angle from the horizontal state to the vertical state, thereby adjusting the air volume, and includes dust having a predetermined diameter or less (abrasive material having a small particle size that is worn and unsuitable for use). .) To the dust collector side.

  The vibration sieve 29 removes foreign matters (curing members used for asbestos removal work, shredded pieces of building accessories, etc.) having a predetermined size or more. That is, the foreign matter is removed, and the abrasive is dropped into the abrasive recovery unit 23b.

  The lower end discharge port of the scouring material recovery unit 23 b is connected to the scouring material inlet 19 b of the pressurized tank 19.

  3) The separated abrasive is used for circulation by opening (opening) the opening / closing valve 33 by exhausting the pressurized tank 19 and returning (inflowing) to the pressurized tank 19 connected to the projection nozzle 13. That is, when the amount of abrasive in the pressurized tank 19 falls below a predetermined level, an exhaust valve (not shown) of the pressurized tank 19 is turned on by a detection signal from the abrasive level meter 35 attached to the pressurized tank 19. Open. Then, the inside of the pressurized tank 19 becomes atmospheric pressure, the open / close valve 33 is opened, and the abrasive in the separator 23 flows into the pressurized tank 19. Thus, the polishing material in the pressurized tank 19 is maintained at a predetermined amount or more.

  In order to reduce the wear of the abrasive during circulation, it is replenished from a replenishing port (not shown) of the separator body 27 at a predetermined cycle.

  4) Dust (usually containing asbestos) separated from the abrasive is removed by a dust collector 37.

Here, the dust inlet 37 a of the dust collector (dust remover) 37 is connected to the dust outlet 23 c of the separator 23 via the dust hose 24. A cartridge filter 39 is disposed at a predetermined position substantially in the center of the dust collecting device 37, and an exhaust port 37b for clean air of the cartridge filter 39 is connected to a suction blower (not shown) through a suction duct. The lower side of the cartridge filter 39 is a funnel-shaped dust collecting portion 38 having a dust collecting port 43 at the lower end. The cartridge filter 39 intermittently blows in compressed air to remove dust adhering to the cartridge filter 39.

  A HEPA filter is provided at a predetermined position between the exhaust port 37b and a suction blower (not shown). The HEPA filter is an abbreviation of “High Efficiency Particulate Air Filter” in English and is defined by JIS Z 8122 as “guaranteing a collection efficiency of 99.97% or more for particles having a particle size of 0.3 μm”. It is what.

  The suction blasting device used in the present embodiment is a truck loading platform in-vehicle type, and in use, the truck loading platform is used as a container system to form a predetermined negative pressure management area to prevent the asbestos dust from being scattered to the outside. Keep it like that. Then, the hose (spout hose, suction hose) is pulled into the work room via a clean room or the like. In the figure, 41 is a control panel.

  In the apparatus having the above configuration, as shown in FIG. 2, the separator 23, the pressurized tank 19 and the dust collecting device 37 may be mounted on a carriage 45 so as to be an indoor carry-in type. In the figure, 47 is a blower.

  In the case of this configuration, a generator and a compressor are mounted on a truck or the like, and the extension cord and the suction hose are a reel type, and the entire carriage is brought into the work place.

  In addition, about the same part, the same figure code | symbol is attached | subjected and those description is abbreviate | omitted. In the case of an indoor carry-in type, the total weight (cart, blast unit, separator, and dust collector) is preferably a size that allows an elevator to be brought in from the viewpoint of handling, and is approximately 100 kg or less.

  In the above asbestos removal work, each suction blasting device (projection material pumping tank, projection material collection cyclone separator, dust collection cyclone separator, dust collection unit, HEPA filter unit, each joint piping unit) is usually isolated and cured. At the same time, it is desirable to install a negative pressure dust removing device in the isolation curing chamber R (see the two-dot chain line in FIGS. 1 and 2) to keep the isolation curing chamber R at a negative pressure.

  Examples performed to confirm the effects of the present invention will be described.

  In place of the asbestos-containing material layer on each base shown in Table 1, the test piece (300 mm square) in which the meteorite spraying material layer (thickness of about 3 mm) was formed, the meteorite spraying material layer was fixed horizontally. After cutting and removing with a spatula until the thickness became approximately 1 to 2 mm, blasting was performed under the displayed conditions using the displayed abrasives.

なお、使用した投射ガンは、ブラストノズル径６ｍｍφ、ダストカバー内径７５ｍｍφ、ブラシ材質：ナイロン０．６ｍｍφ、ブラシ幅：８ｍｍ、ブラシ長さ：５０ｍｍとした。

The projection gun used was a blast nozzle diameter of 6 mmφ, a dust cover inner diameter of 75 mmφ, a brush material: nylon 0.6 mmφ, a brush width: 8 mm, and a brush length: 50 mm.

  In addition, the projection hose and suction hose used were those having an inner diameter of 19 mm and 50 mm, respectively.

  All of these results were cleanly removed as long as they were visually observed, and the substrate was not scratched or distorted.

It is a model figure which shows an example of the vehicle-mounted suction blast apparatus used for the asbestos removal of this invention. Similarly, it is a model diagram showing an example of an indoor carry-in type suction blasting apparatus.

Explanation of symbols

11 Projection suction gun 13 Projection nozzle 15 Bristle brush 17 Suction cover body 19 Pressure tank 22 Projection hose 23 Separator 25 Suction hose (vacuum hose)
37 Dust collector (dust remover)

Claims (6)

A method for removing an asbestos-containing material layer formed on a wall of a structure using a suction blasting device equipped with a projection suction gun,
A scraping step of scraping off the asbestos-containing material layer on the work surface to be subjected to the method, and a blasting step of projecting an abrasive on the work surface after the scraping step,
The projection suction gun includes a projection nozzle and a suction cover body, and the suction cover body is formed of a bristle brush that forms a hermetic space when the entire circumference or a partial circumference of the tip periphery is pressed against the work surface. ,
In the blasting process, while pressing the bristle brush against the work surface, the abrasive material is projected onto the work surface by air pressure at the inner position of the brush, and at the same time, the generated dust is sucked together with the abrasive material. ,
With the bristle brush , the dust generated on the work surface or the surface deposits that are easily peeled off are collected, and the amount of air for suction in the projection suction gun is set to 2 to 30 times the amount of air for projection. The air flow from the outer periphery of the bristle brush to the inside is generated by the suction action of the projection suction gun.
The asbestos removal method characterized by the above-mentioned. The blasting step is
1) Abrading material is projected from the projection nozzle onto the work surface.
2) The dust generated by the projection of the abrasive is sucked together with the abrasive and separated into the abrasive and the dust by a separator.
3) The abrasive is returned to the pressurized tank connected to the projection nozzle for circulation, and the dust is collected by a dust collector.
The asbestos removal method according to claim 1, comprising the steps of:   3. The scraping step is performed with the working surface being wetted, and the blasting step is performed with the working surface being in a wet or dry state lower than the scraping step. Asbestos removal method.   4. The asbestos removal method according to claim 1, wherein the asbestos-containing material layer is solidified by a containment process.   The asbestos according to any one of claims 1 to 4, wherein the blasting step is performed by selecting a type and hardness of the polishing material in accordance with a base material of the structure wall surface and a required finishing degree. Removal method. The asbestos removal according to any one of claims 1 to 5 , wherein cleaning of the work surface after the blasting step is performed only by a suction action without projecting a projection material using the projection suction gun. Method.

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