Coating film removal apparatus and coating film removal method

Abstract

To provide a coating film removal apparatus capable of preventing the scattering of a removed coating film.SOLUTION: The coating film removal apparatus comprises: an isolation box installed to a coating film removal target so as to form a negative-pressure working space, where at least a front section facing the removal target is made of a transparent resin sheet, and the front section is installed with gloves that allow an operator to work inside the working space; a blast gun for spraying an abrasive for removing a coating film from the removal target in the isolation box; a vacuum cleaner driven by compressed air, and configured to suction and collect the sprayed abrasive in the isolation box and the removed coating film via an abrasive recovery hose connected to the inside of the isolation box; and a compressor for generating compressed air to be supplied to the blast gun and the vacuum cleaner. The blast gun and the vacuum cleaner are connected by a hose, and the abrasive is suctioned from the vacuum cleaner and is supplied to the blast gun by the negative pressure generated by injection of compressed air from the blast gun.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a film removing device for removing a film. [Background technology]

[0002] Conventionally, coating removal has been performed using blasting technology. When removing coating by blasting, dust particles and abrasives from the removed coating scatter, so it is necessary to take measures to prevent scattering. In addition, workers are required to wear protective clothing.

[0003] In response to this, for example, Patent Document 1 discloses a blasting work jig that includes a work box with an open bottom that is provided to cover the installation surface, a contact member that is provided at the bottom of the work box and contacts the installation surface, and a blasting device with a nozzle for blasting inside the work box. According to the device in Patent Document 1, blasting work can be performed inside the work box, so that scattering of dust and abrasives can be prevented, and workers can work without wearing protective clothing, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-111873 Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of the device of Patent Document 1, a special fitting member is required to fit the work box to the installation surface, so the fitting member must be prepared in advance, making it difficult to apply to work surfaces of various different shapes. In addition, since the fitting member can basically only be attached to smooth surfaces, it is difficult to apply it to work surfaces with complex shapes.

[0006] In addition, in the device of Patent Document 1, dust and abrasives are sucked up by a suction hose 10 and collected by an air cyclone 16 and a HEPA filter 17. However, when harmful substances such as polychlorinated biphenyls (PCBs) and heavy metals such as lead and chromium are contained in the coating film, it is necessary to collect the removed coating film while preventing it from scattering more reliably, but the device and method of Patent Document 1 may scatter dust. Specifically, after the work is completed, it is necessary to complete disposal without scattering the dust collected by the air cyclone 16, but when removing the collection container that collected the dust in the air cyclone 16, the dust may scatter to the surroundings. Therefore, when harmful substances are contained in the coating film, the device of Patent Document 1 has insufficient function of preventing scattering.

[0007] Therefore, the present application aims to provide a coating removal device that is capable of removing coating from objects of various shapes, and that can prevent scattering even when removing coating that contains harmful substances. [Means for solving the problem]

[0008] The gist of the embodiments of the present application for solving the above problems is as follows.

[0009] (1) An isolation box that is installed in relation to an object from which a coating is to be removed and forms a work space in which removal work is carried out under negative pressure, the isolation box having an installation surface side that is installed on the object to be removed and an opening on the front side that faces the installation surface and is formed of a transparent resin sheet, and gloves are installed on the front side for a worker to use in performing work in the work space; a blast gun that uses compressed air to spray an abrasive for removing the coating film of the object to be removed in the isolation box; a vacuum cleaner that is driven by compressed air and that sucks the abrasive sprayed into the isolation box and the coating film removed from the removal target and collects them in a tank; A coating removal device including the blast gun and a compressor that generates compressed air to be supplied to the vacuum cleaner, A coating removal device characterized in that abrasives are supplied to the blast gun by sucking the abrasives from the tank of the vacuum cleaner with negative pressure generated by the injection of compressed air from the blast gun.

[0010] (2) The coating removal device described in (1) above, characterized in that the isolation box is connected in an airtight manner to the object to be removed by a connection part formed of a resin sheet.

[0011] (3) The coating removal device according to claim 1, further comprising an abrasive recovery hose and a suction hose connected to the isolation box, and the vacuum cleaner sucks air from the abrasive recovery hose and the suction hose.

[0012] (4) A coating removal device as described in (1) above, characterized in that the bottom surface of the isolation box is formed from a resin panel, has an abrasive recovery port for recovering abrasives, and the bottom surface is inclined downward toward the abrasive recovery port.

[0013] (5) A branch portion having a first outlet and a second outlet, each of which can be opened and closed by a valve, and connected to the abrasive recovery port, The coating removal device described in (4) above, wherein the first outlet is connected to the vacuum cleaner, and the second outlet is equipped with a collection container for collecting abrasives.

[0014] (6) The coating removal device described in (1) above, wherein the vacuum cleaner has an abrasive discharge port that opens into the tank, and abrasive is supplied to the blast gun from the abrasive discharge port.

[0015] (7) An isolation box which is installed in relation to an object from which a coating film is to be removed and forms a work space in which removal work is carried out under negative pressure, the isolation box having an opening on the installation surface side which is installed on the object to be removed and a front side which faces the installation surface and is formed of a transparent resin sheet, and on the front side are installed gloves for a worker to use in working within the work space; a blast gun that uses compressed air to spray an abrasive for removing the coating film of the object to be removed in the isolation box; a vacuum cleaner that is driven by compressed air and that sucks the abrasive sprayed into the isolation box and the coating film removed from the removal target and collects them in a tank; A coating film removal method using a coating film removal device including the blast gun and a compressor that generates compressed air to be supplied to the vacuum cleaner, A coating removal method comprising the steps of: supplying an abrasive to the blast gun by sucking the abrasive from the tank of the vacuum cleaner using negative pressure generated by the injection of compressed air in the blast gun; and circulating the abrasive between the blast gun and the vacuum cleaner to remove the coating.

[0016] (8) The coating removal method according to (7) above, characterized in that the isolation box is connected in an airtight manner to the object to be removed by a connection part formed of a resin sheet.

[0017] (9) The coating removal method described in (7) above, further comprising an abrasive recovery hose and a suction hose connected to the isolation box, and the vacuum cleaner sucks from the abrasive recovery hose and the suction hose.

[0018] (10) The coating removal method described in (7) above, characterized in that the bottom surface of the isolation box is formed from a resin panel and has an abrasive recovery port for recovering abrasives, the bottom surface is inclined downward toward the abrasive recovery port, and the abrasive sprayed from the blast gun is recovered from the abrasive recovery port into the vacuum cleaner.

[0019] (11) The coating removal method described in (10) above, characterized in that the coating removal device has a first outlet and a second outlet, each of which can be opened and closed by a valve, and is equipped with a branching section connected to the abrasive recovery port, the first outlet is connected to the vacuum cleaner, and the second outlet is equipped with a recovery container for recovering the abrasive, and when the removal work is completed, the used abrasive is recovered from the second outlet to the recovery container.

[0020] (12) The coating removal method described in (7) above, characterized in that the vacuum cleaner has an abrasive discharge port that opens into the tank, and abrasive is supplied to the blast gun from the abrasive discharge port. Effect of the Invention

[0021] According to one aspect of the embodiment, a coating removal device can be provided that is capable of removing coatings from objects of various shapes, and can prevent scattering even when removing coatings that contain harmful substances. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic diagram of a coating removal device according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing a configuration of an isolation box according to an embodiment. [Diagram 3] FIG. 2 is a side view showing a configuration of the isolation box according to the embodiment. [Figure 4] 1 is a configuration diagram showing a structure of a vacuum cleaner according to an embodiment; [Diagram 5] 1 is a flowchart showing steps of a coating removal method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The coating removal device of this embodiment will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of the coating removal device 1 of this embodiment. The coating removal device 1 of this embodiment forms an isolated work space according to the shape of the work surface where the coating removal is performed, and maintains a negative pressure within the work space to reliably prevent the removed dust from scattering, so that the work can be completed safely without the collected abrasive, dust, etc. scattering or flowing out to the outside even after the work is completed.

[0024] The coating removal apparatus 1 of this embodiment includes an isolation box 2, a blast gun 4, a glove 6, a vacuum cleaner 8, a compressor 10, an air tank 12, branch pipes 14, 16, and valves 18, 20. These components are connected by various hoses 22 to 29. The coating removal apparatus 1 is an apparatus in which an operator holds the blast gun 4 with the glove 6 inside the isolation box 2 and sprays an abrasive material against the object 100 to remove the coating from the object 100 to remove the coating.

[0025] In Fig. 1 and other figures of this embodiment, the object 100 to be removed from the paint film is, as an example, a steel bridge girder with an I-shaped (or H-shaped) cross-sectional shape, and a case will be described in which the paint film is removed from the side of the bridge girder using the paint film removal device 1. However, the object to be removed from the paint film is not limited to the bridge girder, and may be other parts of the bridge on which a paint film is formed. Furthermore, in addition to bridges, the paint film removal device 1 of this embodiment can be used to remove paint films from tanks (oil storage tanks, gas tanks, etc.), water gates, ships, tunnels, and various other facilities by blasting.

[0026] As described later, the coating film can be removed in a sealed working space by installing the coating film removal target 100 and the isolation box 2 of the coating film removal device 1 with no gap between them. Therefore, coating film removal can be performed on targets of various shapes and structures without scattering harmful substances contained in the coating film to the outside. For example, this is useful when removing coating films that contain harmful substances such as polychlorinated biphenyls (PCBs) and heavy metals such as lead and chromium.

[0027] Each part of the coating removal device 1 will be described. First, the isolation box 2 is a work box for forming a work space in which blasting is performed. The configuration of the isolation box 2 is shown in a perspective view of the isolation box 2 in FIG. 2 and a side view of the isolation box 2 in FIG. 3. The isolation box 2 is composed of a frame 50 and transparent sheets and panels that make up each surface (parts other than the frame). By using transparent sheets and panels, it is possible to perform removal work while checking inside the isolation box 2. The side of the isolation box 2 that is placed on the object 100 to be coated 100 is the installation side, and the side facing the installation side and where the glove port 6a for the glove 6 is located is the front side where the worker stands and performs work.

[0028] The frame 50 is substantially rectangular, but in this embodiment, the upper part of the front side is inclined by the inclined frame 50f so that the worker can easily work. However, the shape is not limited to this, and any box shape that can secure a space for operating the blast gun 4 in the isolation box 2 may be used. The frame 50 is composed of an upper end frame 50a at the upper end, a middle frame 50c at the middle, a lower end frame 50d at the lower end, a front bar 50b, a front column 50e, an inclined frame 50f, and an installation surface column 50g. Except for the installation surface (rear) side of the isolation box 2, each surface (upper surface, front surface, both sides, and lower surface) in the range from the upper end frame 50a to the middle frame 50c is covered with a transparent sheet (or film) or panel. In other words, the isolation box 2 is only open on the installation surface side. In this embodiment, an example is shown in which the frame exists below the isolation space, but as long as the isolation space can be formed, the frame below the middle frame 50c may be omitted. Also, as shown in FIG. 3, depending on the height at which the isolation box 2 is installed, legs may be provided under the frame 50, and wheels may be provided on the legs to facilitate mobility.

[0029] Of the surface portions formed by the frame 50, at least the front surface 52a where the globe 6 (glove port 6a) is disposed is covered with a transparent sheet. In this embodiment, the front surface 52a is the gray filled area surrounded by a dashed line in Fig. 2. In this embodiment, the front surface 52a in the range from the front surface bar 50b on the front side to the middle frame 50c is covered with a transparent sheet.

[0030] The sheet used for the front surface 52a, etc. may be a transparent resin sheet or film. It may be cut into any shape when the isolation box 2 is installed. The resin sheet may be, for example, a polyolefin such as polyethylene or polypropylene, or an ethylene vinyl acetate (EVA) sheet. The sheet may be attached to the frame 50, etc., using an adhesive tape such as masking tape. When attaching the sheet, no gap is formed between the sheet and the frame 50, etc., so that the airtightness inside the isolation box 2 is maintained. The sheet used should be strong enough not to break even when pulled by the negative pressure inside the isolation box 2, and not to break even when working with gloves 6. It should also be strong enough not to break even when hit by abrasive material rebounded from blasting. The thickness of the sheet is not particularly limited, but is preferably 0.15 mm or more.

[0031] By forming the front surface 52a from a sheet, the removal work can be performed more quickly and efficiently by removing the sheet and the glove attached to the sheet together rather than removing only the glove 6 portion during the removal work after the work. In addition, since the front surface 52a is a flexible sheet, the degree of freedom of the work is high and the blasting work can be performed easily. Specifically, when the front surface is a resin panel, the body hits the panel, so the arm can only be inserted halfway. On the other hand, when the front surface 52a is a sheet, the sheet deforms, so the arm can be inserted all the way and the blasting work is easy. As a result, even if the removal target 100 has a complex shape, the coating film can be removed reliably by operating the blast gun 4. In addition, since the work is easy, the work can be performed quickly.

[0032] The upper surface 52b and both side surfaces 52c above the front bar 50b (the area hatched with diagonal lines surrounded by a dashed line in FIG. 2) may be formed of a transparent sheet similar to the front surface 52a, or may be formed of a transparent resin panel. Note that the isolation box 2 of this embodiment has a structure in which the upper surface 52b includes a partial inclined surface, but the front bar 50b may be at the same upper end position as the upper end frame 50a. In that case, the upper surface 52b does not include an inclined surface, and the inclined surface of the front surface 52a continues to the upper end.

[0033] In this embodiment, the lower surface 52d formed on the middle frame 50c is preferably formed of a resin panel. The lower surface 52d does not necessarily have to be transparent, but is preferably transparent for ease of work. The lower surface 52d is formed with an abrasive recovery port 60, and the abrasive and dust are sucked and collected by the vacuum cleaner 8 through the connected branching section 30 and abrasive recovery hose 27. The lower surface 52d is formed with a surface that slopes downward toward the abrasive recovery port 60 formed below the middle frame 50c. In this embodiment, an inclined surface that combines four triangular surfaces is shown as an example. The downward inclined surface makes it easier for the sprayed abrasive to flow to the abrasive recovery port 60, making it easier to collect the abrasive.

[0034] Furthermore, since the underside 52d is formed from a resin panel, it is less likely to deform inward even when negative pressure is created inside the isolation box 2 due to suction by the vacuum cleaner 8, so that the above-mentioned inclination is maintained and a state in which the abrasive can be easily collected is maintained, allowing the abrasive to be collected more smoothly.

[0035] Since the abrasive is sucked by the vacuum cleaner 8, the lower surface 52d does not necessarily have to be inclined and may be flat. The lower surface 52d may be formed of a transparent sheet similar to the front surface 52a. If the lower surface 52d is formed of a sheet, the sheet will deform due to negative pressure, but even if it is deformed, the abrasive can be collected by the suction force of the vacuum cleaner 8.

[0036] When a transparent resin panel is used for a surface other than the front surface 52a, the resin may be an acrylic resin, polyvinyl chloride, polycarbonate, or the like.

[0037] The gap between the isolation box 2 and the object 100 to be removed is then sealed with the sheet, so that the work space formed by the isolation box 2 and the object 100 to be removed is sealed. As shown in FIG. 3, when the object 100 to be removed is the side of an I-beam bridge girder, gaps are formed on both sides between the steel plate (web) portion facing the isolation box 2 and the steel plate (flange) portions above and below it. Therefore, a sheet is installed as a connection portion 52e that fills the gap and connects to the isolation box 2. The connection portion 52e is shown as a gray filled area surrounded by a dashed line in FIG. 3. The connection portion 52e is formed by attaching a sheet to the isolation box 2 at both side surfaces 52c of the isolation box 2 so as to close the gap between the isolation box 2 and the object 100 to be removed. The end of the sheet on the isolation box 2 side is then fixed to the frame 50 or the like with masking tape. The connection portion 52e is formed not only on the side surface but also at the connection portion with the upper portion and the connection portion with the lower portion of the object 100 to be removed. In the example of Figure 3, there is a step between the lower flange of the I-beam and the underside 52d of the isolation box 2, creating a gap, so a sheet is installed to seal the area from the flange side to the underside 52d in an airtight manner.

[0038] The sheet of the connection part 52e may be a single sheet formed into a cylindrical shape to close all the gaps that occur at the connection part between the object 100 to be removed and the isolation box 2. Also, separate sheets for the sides, upper side, lower side, etc. may be prepared and connected to close all the gaps. The sheet that forms the connection part 52e can be attached using an adhesive tape such as masking tape as described above. By connecting the isolation box 2 at the connection part 52e in this way, a sealed isolation space can be formed between the object 100 to be removed and the isolation box 2.

[0039] In addition to the left and right globes 6 (glove ports 6a), an air hose connection port 54 and an abrasive supply hose connection port 56 are arranged on the front surface 52a of the isolation box 2. In FIG. 1, the air hose connection port 54 and the abrasive supply hose connection port 56 are shown shifted up and down from the position of the globe 6 for ease of understanding. The air hose connection port 54 and the abrasive supply hose connection port 56 can be arranged at an appropriate position on the front surface 52a. The air hose connection port 54 is connected to the air hose 24, and compressed air is supplied from the air tank 12. The abrasive supply hose connection port 56 is connected to the abrasive supply hose 26, and the abrasive is transported from the vacuum cleaner 8 and supplied to the blast gun 4. In addition, a water supply hose connection port through which a hose for supplying water to wash the inside of the isolation box 2 after the work is completed can be arranged at an appropriate position on the front surface 52a, etc., as necessary.

[0040] An air intake port 58 is formed above one side surface 52c of the isolation box 2. A suction hose 28 is connected to the air intake port 58, and air is mainly sucked in by a vacuum cleaner 8 connected via a branch pipe 16 or the like. Dust may also be sucked in through the air intake port 58. By sucking in air not only from the air intake port 58 but also from the air intake port 58, even if abrasives or the like flow into the abrasive collection port 60 and the amount of air suction decreases, air is still sucked in through the air intake port 58, so that the inside of the isolation box 2 can be reliably maintained at a negative pressure.

[0041] The amount of air sucked by the vacuum cleaner 8 from the intake port 58 and the abrasive recovery port 60 is adjusted so that negative pressure is created inside the isolation box 2. In other words, the amount of air sucked by the vacuum cleaner 8 is adjusted to be greater than the amount of air supplied from the blast gun 4 to the isolation box 2. The air pressure inside the isolation box 2 can be adjusted by the pressure regulating valves of the compressor 10 and the air tank 12, or by valves 18, 20 appropriately arranged midway along the hose.

[0042] By covering at least the front surface of the isolation box 2 with a sheet, it is possible to check at a glance whether or not the inside of the isolation box 2 is under negative pressure during the work described below. That is, during the coating removal work, the air sucked by the vacuum cleaner 8 is made greater than the air supplied from the blast gun 4 to prevent dust and the like from scattering, creating a negative pressure inside. At this time, since at least the front surface 52a of the isolation box 2 is made of a sheet, if there is negative pressure, the sheet portion is deformed as if pulled inward. Therefore, it is possible to visually check that the inside of the isolation box 2 is under negative pressure, and the removal work can be performed safely.

[0043] The blast gun 4 is a tool that sprays an abrasive to remove the coating. The blast gun 4 may be gun-shaped or nozzle-shaped. The blast gun 4 of this embodiment performs a blasting process by generating negative pressure in the gun by the flow of compressed air supplied from the air tank 12 through the air hose 24, and spraying the abrasive with the compressed air while sucking in the abrasive with the negative pressure. The abrasive is sucked and supplied from the vacuum cleaner 8 connected through the abrasive supply hose 26. Note that the blast gun 4 and the vacuum cleaner 8 do not necessarily need to be directly connected by the abrasive supply hose 26, and a valve or the like may be arranged in between, as long as the abrasive can be sucked from the vacuum cleaner 8 and supplied to the blast gun 4.

[0044] In the blast gun 4 of this embodiment, the blasting process is performed by circulating the abrasive between the blast gun 4 and the vacuum cleaner 8. That is, the abrasive sprayed from the blast gun 4 and the dust of the removed coating are sucked into the abrasive recovery port 60 below the isolation box 2 by the vacuum cleaner 8. Then, when the abrasive is collected by the vacuum cleaner 8 via the branching portion 30 and the abrasive recovery hose 27, the abrasive is sucked out from the vacuum cleaner 8 again and supplied to the blast gun 4 via the abrasive supply hose 26, and this circulation is repeated to perform the blasting process. That is, the abrasive sprayed from the blast gun circulates through the circulation path of this device in the order of the abrasive recovery port 60, the abrasive recovery hose 27, the vacuum cleaner 8, the abrasive supply hose 26, and the blast gun 4, and is continuously used for the blasting process.

[0045] By circulating the abrasive during blasting, the blasting can be performed with a smaller amount of abrasive. By reducing the amount of abrasive used, the amount of abrasive used can be reduced, and as a result, the amount of contaminated waste after work can be reduced. In addition, the smaller amount of waste makes it easier to handle the waste disposal and more reliably prevents the scattering of dust.

[0046] The glove 6 is used to perform work such as blasting in the isolation box 2. A worker holds the blast gun 4 with both hands through the glove 6, and can freely change the position and direction of the blast gun 4 in the isolation box 2 to perform the blasting. The glove 6 is attached to a glove port 6a provided in a sheet on the front surface 52a of the isolation box 2. The glove 6 may be made of any material and structure as long as it is structured to maintain the isolation box 2 in a sealed state and ensures workability. For example, the entire glove 6 may be made of rubber, or the arm portion may be made of a resin sheet and only the hand portion may be made of a rubber glove.

[0047] The vacuum cleaner 8 is a device for suctioning and collecting the abrasive sprayed from the isolation box 2 and the removed coating film. The structure of the vacuum cleaner 8 is shown in FIG. 4. FIG. 4(a) is a schematic diagram showing the configuration of the vacuum cleaner, and FIG. 4(b) is a schematic cross-sectional view at the AA position shown in (a). The vacuum cleaner 8 has a tank 8a for collecting and storing the suctioned material, a lid 8b, a compressed air supply port 8c, an air exhaust port 8d, a suction hose connection port 8e, a float 8f, and the like. The vacuum cleaner 8 of this embodiment further has an abrasive delivery port 8g. The abrasive delivery port 8g is formed below the tank 8a and opens into the tank 8a, and an abrasive supply hose 26 is connected to the abrasive delivery port 8g, and the collected abrasive is delivered from the tank 8a to the blast gun 4.

[0048] The vacuum cleaner 8 of this embodiment is an air-driven vacuum cleaner. Compressed air is supplied from the compressor 10 and the air tank 12 through the air hoses 23 and 25 to the compressed air supply port 8c, and is discharged from the air exhaust port 8d, creating a negative pressure inside the tank, which can be used to suck in the abrasives and dust from the isolation box 2. By making the vacuum cleaner 8 air-driven, a power source for the vacuum cleaner 8 is not required, and both the blasting process and the collection of the coating and abrasives can be performed by a single compressor 10 and air tank 12.

[0049] As shown in Fig. 4, the sucked abrasive and dust from the removed coating pass through the suction hose 29 and flow into the tank 8a from the suction hose connection port 8e. The abrasive is then sucked into the abrasive delivery port 8g by the suction force from the blast gun 4, and is then sent back to the blast gun 4 for use in the blasting process. A filter such as a HEPA filter is placed between the inside of the tank 8a and the air outlet 8d, so that dust does not flow out and only air is discharged.

[0050] The compressor 10 and the air tank 12 are devices that generate compressed air. The compressor 10 generates compressed air, the air tank 12 stores the compressed air, and supplies the compressed air to the blast gun 4 and the vacuum cleaner 8 as needed. The compressed air generated by the compressor 10 and the air tank 12 is supplied to the blast gun 4 and used to suck and spray abrasives. The compressed air is also supplied to the vacuum cleaner 8 and used to drive the vacuum cleaner 8 as described above. The air tank 12 and the compressor 10 preferably have a pressure regulating valve so that the pressure of the compressed air to be supplied can be adjusted.

[0051] There is no particular limitation on the type of compressor 10, and any engine-type or motor-type compressor of any compression method can be used. In addition, if the compressor 10 alone can adequately supply compressed air, the air tank 12 may be omitted.

[0052] Branch pipe 14 branches compressed air supplied from air tank 12 into a path for supplying it to blast gun 4 and a path for supplying it to vacuum cleaner 8. If compressed air can be supplied directly from air tank 12 to two hoses, branch pipe 14 may be omitted. Branch pipe 16 is a branch that joins abrasive recovery hose 27 and suction hose 28 that perform suction from isolation box 2, and is connected to vacuum cleaner 8 via suction hose 29 on the downstream side.

[0053] The valve 18 is disposed between the air tank 12 and the blast gun 4, and is used to adjust the amount of compressed air supplied from the air tank 12 or to stop the supply. The valve 20 is disposed between the air tank 12 and the vacuum cleaner 8, and is similarly used to adjust the amount of compressed air supplied from the air tank 12 or to stop the supply.

[0054] Air hoses 22 to 25 are hoses for supplying compressed air from compressor 10. Air hose 22 connects compressor 10 and air tank 12, air hose 23 connects air tank 12 and branch pipe 14, air hose 24 connects branch pipe 14 and blast gun 4, and air hose 25 connects branch pipe 14 and vacuum cleaner 8.

[0055] The abrasive supply hose 26 is a hose for supplying an abrasive from the vacuum cleaner 8 to the blast gun 4. The abrasive supply hose 26 is connected to the abrasive supply hose connection port 56 of the isolation box 2. The abrasive recovery hose 27 is a hose for recovering the sprayed abrasive from the abrasive recovery port 60 to the vacuum cleaner 8, and is connected to the outlet of the valve 31 side of the branching section 30 in this embodiment. The suction hose 28 is connected to the intake port 58 of the isolation box 2, and is used to suck air from inside the isolation box 2 by the suction force of the vacuum cleaner 8. The suction hose 29 is a hose that is connected to the abrasive recovery hose 27 and the suction hose 28 by the branching pipe 16, and is connected to the vacuum cleaner 8. Note that each of the hoses 22 to 29 used in this embodiment does not necessarily have to be formed of a single hose, and may be formed by connecting a plurality of hoses.

[0056] The branching section 30 is a branch connected to the abrasive collection port 60, and has a first outlet to which the abrasive collection hose 27 is attached and connected to the vacuum cleaner 8, and a second outlet to which a collection bag 33, which is a collection container for collecting abrasives after the work is completed, is attached. Valves 31 and 32 are arranged at each outlet and can be opened and closed. When circulating the abrasives during blasting work, the valve 31 at the first outlet is opened and the valve 32 at the second outlet is closed. On the other hand, when collecting the abrasives in the collection bag 33, the valve 31 is closed and the valve 32 is opened to perform the collection work. By collecting the used abrasives and dust in the collection bag 33, the abrasives can be collected at the end of the work without scattering dust to the outside. The second outlet of the valve 32 can also be used for drainage by attaching a tank or the like when washing the inside of the isolation box 2 with water.

[0057] The coating removal device 1 can further include a differential pressure gauge 21. The differential pressure gauge 21 is used to confirm that the inside of the isolation box 2 is at negative pressure. The differential pressure gauge 21 can be a known differential pressure gauge (manometer) with two measurement ports. For example, when the differential pressure gauge 21 is disposed outside the isolation box 2, a tube connected to the measurement port on the negative pressure side is installed inside the isolation box 2, and the pressure outside the box (atmospheric pressure) is measured with the measurement port on the positive pressure side, thereby making it possible to measure the pressure difference between inside and outside the box. The above is the configuration of the coating removal device 1 of this embodiment.

[0058] Next, a coating removal method performed using the coating removal device 1 of this embodiment will be described. FIG. 5 is a flow chart showing each step of the coating removal method. First, the isolation box 2 is installed (step 101). As long as the isolation box 2 can be installed in an airtight state, the installation procedure is not limited, but for example, the installation surface side (back side) of the isolation box 2 with no sheet attached to the front surface 52a is placed in close contact with the object 100 from which the coating is to be removed. Then, a sheet is installed at the connection portion 52e to connect the object 100 from which the coating is to be removed and the isolation box 2 so that no gap is generated between them.

[0059] Then, with gloves 6 attached to the glove ports 6a on both sides, the sheet on the front surface 52a is placed on the frame 50. At the abrasive supply hose connection port 56 and the air hose connection port 54, the hose and the connection port are fixed in an airtight state with masking tape or the like. In addition, the abrasive supply hose 26 passed through the abrasive supply hose connection port 56 and the air hose 24 passed through the air hose connection port 54 are connected to the blast gun 4.

[0060] The sheet is attached using an adhesive tape such as masking tape as described above. When surfaces other than the front surface 52a and the connecting portion 52e are also formed with sheets, the sheets may be attached in the same manner or may be attached to those surfaces in advance.

[0061] Next, other equipment is installed (step 102). Specifically, the compressor 10, air tank 12, vacuum cleaner 8, etc. are connected with various hoses. Also, the isolation box 2 is connected with the vacuum cleaner 8, air tank 12, etc. with various hoses. Also, the valve 31 of the branching section 30 is opened, and the valve 32 is closed. Note that the order of steps 101 and 102 is not limited to this, and they may be performed in parallel or in the reverse order.

[0062] After the above preparation steps are completed, the blasting process is performed (step 103). Specifically, first, the abrasive is put into the tank 8a of the vacuum cleaner 8. Then, the compressor 10 is driven, and the valves 18, 20, etc. are opened to supply compressed air to the blast gun 4 and the vacuum cleaner 8. Then, the worker operates the blast gun 4 with the glove 6, supplies the abrasive from the vacuum cleaner 8, and causes it to be sprayed from the blast gun 4. When the isolation box 2 is installed and the blasting process is started for the first time, the abrasive may be stored on the lower surface 52d or in a container in the isolation box 2, and the abrasive may be directly sucked in from there and sprayed by the blast gun 4. After the abrasive has been sucked in, the tip of the abrasive supply hose 26 is connected to the blast gun 4, and the abrasive is circulated as described above to perform continuous blasting.

[0063] In the coating removal device 1 of this embodiment, the blast gun 4 is held by the glove 6 in the isolation box 2, and its position and orientation can be freely changed. Therefore, even in places where it is difficult to remove coating due to their complex shapes, such as the heads of bolts in the splices of bridge girders as shown in Figures 1 and 3, coating can be reliably removed by blasting.

[0064] When the removal of the coating from the coating removal target 100 in the area partitioned by the sheet of the connection portion 52e is completed, the blasting process is terminated. Before the start of the blasting process and during the blasting process, the worker checks whether the sheet (front surface 52a) of the isolation box 2 is deformed toward the inside of the box and checks the differential pressure gauge 21 to constantly check that the inside of the isolation box 2 is in a negative pressure state.

[0065] Next, the abrasives and peeled off paint are collected (step 104). First, a collection bag 33 is attached to the outlet on the valve 32 side of the branching section 30. Then, the valve 31 is closed and the valve 32 is opened. As a result, the abrasives sprayed from the blast gun 4 and the removed coating film flow from the abrasives collection port 60 into the collection bag 33 and are collected.

[0066] By using this method of recovery, neither coating dust nor used abrasives are scattered outside during recovery or disposal, and recovery and disposal work can be performed safely. If a sealed state is maintained inside the coating removal device 1 and the abrasives are to be used continuously, the abrasives may be recovered in the vacuum cleaner 8. By operating the vacuum cleaner 8 without blasting with the blast gun 4, the abrasives can be recovered in the vacuum cleaner 8.

[0067] After the abrasives and the like have been collected, the isolation box 2 and the like are removed (step 105). Dust and the like from the removed coating are attached inside the isolation box 2. For this reason, it is preferable to first provide a water supply hose connection port, for example, on the front surface 52a inside the isolation box 2, pass a hose through which water is supplied in advance, and then, after the work is completed, supply water and wash the walls and the like inside the isolation box 2 with water to remove dust and the like. The water is collected by connecting a drainage tank to the second outlet of the branching portion 30 of the abrasives collection port 60 of the isolation box 2. Water is also poured on the coating removal target 100 to remove any attached dust. Alternatively, instead of washing with water through a hose, a sprayer filled with water may be placed inside the isolation box 2 in advance, and after the work is completed, the isolation box 2 and the coating removal target 100 may be sprayed with water to wet them. Wetting with water can also prevent dust from scattering during removal.

[0068] Once the water washing is complete, the sheets on the front surface 52a, the connection portion 52e, etc. are removed and discarded. Because the sheet portion is washed away with water, it is possible to prevent dust from scattering during removal. Then, the isolation box 2 and other devices are removed. This is the flow of the coating film removal method of this embodiment.

[0069] Furthermore, if the coating removal process is to be continued on an adjacent position on the coating removal target 100, the isolation box 2, etc. can be moved to the next blast position and the procedure from step 101 can be repeated to perform the coating removal process.

[0070] According to the present embodiment described above, the coating film can be reliably removed by a single blasting process while preventing scattering of dust from the removed coating film. That is, the coating film can be reliably removed from the surface of the coating film removal target 100 while preventing scattering of the removed dust. In addition, the worker can perform the work without wearing protective clothing or the like.

[0071] Furthermore, in the case of conventional methods of isolating the entire object to be coated on a large scale to remove the coating, preparation and removal require time. However, according to the present embodiment, the isolation box 2 is installed only for the part to be treated and the necessary isolation process is performed, so that installation, work, and removal can be completed in a short time. For example, in the case of coating removal work on a railway bridge, it may be performed in the limited time between the last train of the day and the first train of the next day. Even in such a case, according to the present embodiment, the installation and removal work can be performed quickly, so that the coating removal work can be performed quickly. In addition, the work can be performed quickly because the worker does not need to wear protective clothing.

[0072] Furthermore, according to this embodiment, the removed coating film or the abrasive with the used coating film attached thereto can be collected in a container such as collection bag 33 that can be disposed of as is within a sealed working space. On the other hand, when collecting in the tank of a vacuum cleaner, for example, it is necessary to open the tank to take out the collected abrasive and dust, or to transfer the collected abrasive and dust from the tank to another bag, and there is a high possibility that the dust will fly and scatter at this time. However, according to this embodiment, collection can be carried out in a sealed space in a state where it can be disposed of as is, so scattering at the time of disposal can be reliably prevented.

[0073] In addition, in this embodiment, the abrasive is circulated to remove the coating, so the amount of abrasive used can be minimized. By reducing the amount of abrasive used, the amount of contaminated abrasive waste generated at the end of the work can also be reduced. The reduced amount of waste improves the work efficiency during removal, etc.

[0074] In this embodiment, the object 100 to be removed is an I-shaped bridge girder, but it is of course possible to perform coating removal on a planar object 100 to be removed. In that case, the installation surface (rear surface) side of the frame 50 of the isolation box 2 is placed in close contact with the surface of the object to be removed, and the gap with the object 100 to be removed is closed with the connection part 52e to create an airtight state.

[0075] Furthermore, the isolation box 2 may be configured with a frame that is expandable in the horizontal and vertical directions. In this case, the size of the isolation box 2 can be changed according to the size of the object 100 to be removed, so that it can accommodate objects 100 of various sizes. For example, if the top surface 52b, the front surface 52a, and the bottom surface 52d of the isolation box 2 are formed from resin sheets that can be processed on the spot to any size, one frame 50 can accommodate work spaces of various widths. [Explanation of symbols]

[0076] 1 Paint film removal equipment 2. Isolation Box 4 Blast Gun 6. Gloves 8 Vacuum Cleaner 10. Compressor 12 Air Tank 14, 16 Branch pipe 18, 20 valves 22~25 Air hose 26 Abrasive supply hose 27 Abrasive recovery hose 28, 29 Suction hose 50 frames 52e Connection 54 Air hose connection port 56 Abrasive supply hose connection port 58 Air Intake 60 Abrasive collection port

Claims

1. an isolation box which is installed in relation to an object from which a coating is to be removed and forms a work space in which removal work is carried out under a negative pressure state, the isolation box having an installation surface side which is installed on the object to be removed and an opening on a front side which faces the installation surface and is formed of a flexible, deformable, transparent resin sheet, and gloves are installed on the resin sheet on the front side so that a worker can work in the work space; a blast gun that uses compressed air to spray an abrasive for removing the coating film of the object to be removed in the isolation box; a vacuum cleaner that is driven by compressed air and that sucks the abrasive sprayed into the isolation box and the coating film removed from the removal target and collects them in a tank; A coating removal device including the blast gun and a compressor that generates compressed air to be supplied to the vacuum cleaner, A coating removal device characterized in that abrasives are supplied to the blast gun by sucking the abrasives from the tank of the vacuum cleaner with negative pressure generated by the injection of compressed air from the blast gun.

2. 2. The coating removal device according to claim 1, wherein the resin sheet is a sheet of polyolefin or ethylene vinyl acetate.

3. 2. The coating removal device according to claim 1, wherein the isolation box is airtightly connected to the object to be removed by a connection part formed of a resin sheet and fixed to the object to be removed by adhesive tape.

4. The coating removal device described in claim 1, characterized in that it comprises an abrasive recovery hose connected to the isolation box, an abrasive recovery hose connected to the upper part of the isolation box, and an abrasive recovery port formed on the underside of the isolation box, and the vacuum cleaner sucks through the abrasive recovery port and the abrasive recovery hose, and also sucks through the suction hose.

5. The coating removal device described in claim 1, characterized in that the bottom surface of the isolation box is formed of a resin panel, has an abrasive recovery port for recovering abrasives, and the bottom surface is inclined downward toward the abrasive recovery port.

6. a branch portion having a first outlet and a second outlet, each of which can be opened and closed by a valve, and connected to the abrasive recovery port; 6. The coating removal device according to claim 5, wherein the first outlet is connected to the vacuum cleaner, and the second outlet is provided with a collection container for collecting the abrasive.

7. an isolation box which is installed in relation to an object from which a coating is to be removed and forms a work space in which removal work is carried out under a negative pressure state, the isolation box having an installation surface side which is installed on the object to be removed and an opening on a front side which faces the installation surface and is formed of a flexible, deformable, transparent resin sheet, and gloves are installed on the resin sheet on the front side so that a worker can work in the work space; a blast gun that uses compressed air to spray an abrasive for removing the coating film of the object to be removed in the isolation box; a vacuum cleaner that is driven by compressed air and that sucks the abrasive sprayed into the isolation box and the coating film removed from the removal target and collects them in a tank; A coating film removal method using a coating film removal device including the blast gun and a compressor that generates compressed air to be supplied to the vacuum cleaner, A coating removal method comprising the steps of: supplying abrasives to the blast gun by sucking the abrasives from the tank of the vacuum cleaner using negative pressure generated by the injection of compressed air in the blast gun; and circulating the abrasives between the blast gun and the vacuum cleaner during blasting operation to remove the coating.

8. The coating removal method according to claim 7, characterized in that the isolation box is connected in an airtight manner to the object to be removed by a connection part formed of a resin sheet and fixed to the object to be removed with adhesive tape.

9. The coating removal method described in claim 7, characterized in that the method comprises an abrasive recovery hose connected to the isolation box, an abrasive recovery hose connected to the upper part of the isolation box, and an abrasive recovery port formed on the underside of the isolation box, and the vacuum cleaner sucks through the abrasive recovery port and the abrasive recovery hose, and also sucks through the suction hose.

10. The coating removal method described in claim 7, characterized in that the bottom surface of the isolation box is formed of a resin panel and has an abrasive recovery port for recovering abrasives, the bottom surface is inclined downward toward the abrasive recovery port, and the abrasives sprayed from the blast gun are recovered from the abrasive recovery port into the vacuum cleaner.

11. The coating removal method described in claim 10, characterized in that the coating removal device has a branch section connected to the abrasive recovery port, each of which has a first outlet and a second outlet that can be opened and closed by a valve, the first outlet is connected to the vacuum cleaner, and the second outlet is equipped with a recovery container for recovering the abrasive, and when the removal work is completed, the used abrasive is recovered from the second outlet to the recovery container.

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