JP4946571B2 - Deposit removal method - Google Patents

Description

The present invention relates to a deposit removing process.

  Various methods for removing deposits attached to the wall surface are disclosed. Among the disclosed techniques, there is a technique of removing harmful substances in a work place by spraying dry ice particles with compressed air compressed by a compressor (Patent Document 1). And the asbestos removal construction method using this technique is used. The asbestos removal method used is to place a compressor and dry ice transporter outside the workplace. And the dry ice grain thrown into the dry ice conveyance machine is injected from an injection nozzle with the high pressure air of a compressor, and asbestos, such as a wall surface, is removed.

Further, Patent Document 2 discloses a technology for blasting sublimable particles such as dry ice to peel off and remove deposits.
JP 2003-300030 A JP 2004-305904 A

  When removing harmful substances such as asbestos adhering to the wall surface etc. using the above asbestos removal method, the work place is isolated and sealed. And it is necessary to make the atmospheric | air pressure of the room | chamber interior isolated and sealed using a negative pressure dust collector etc. into a pressure lower than the outdoor, and to prevent the harmful | toxic harmful | toxic substance in the removed indoor from leaking outside.

  At this time, when dry ice is jetted in a room maintained at a lower pressure than the outside by compressed air of a compressor installed outside the room, the atmospheric pressure in the room significantly increases. Therefore, it is necessary to use a large-scale negative pressure dust collector or install many negative pressure dust collectors in order to keep the atmospheric pressure in the room lower than the outdoor pressure. Many installations of such devices are costly.

  In addition, since the compressor is usually large, it is installed outside the room, and it is necessary to make a hole in the sealed curing material for connecting a hose for sending compressed air into the room. Since this hole impairs the airtightness of the room, it is difficult to keep the room at a low pressure. This is also a factor that requires use of a large negative pressure dust collector or the like. Thus, the use of a large-sized negative pressure dust collector and a large-sized compressor installed outdoors has been a cause of increasing the construction cost due to the cost of fuel and the like.

  This invention is made | formed in view of such a situation, and it aims at removing the deposit | attachment adhering to the to-be-cleaned surface at low cost in the low pressure chamber maintained at the atmospheric | air pressure lower than an external pressure.

In order to achieve such an object, the deposit removing method according to the present invention attaches a sheet to the periphery of a window and provides an air flow path between the room and the outside for the doorway. A sheet is provided in the form of a curtain, and the room is isolated and sealed, and the room air is sucked and exhausted to the outside of the room to make the room a low-pressure room having an atmospheric pressure lower than the outside pressure, and is installed in the low-pressure room. By sending out the air taken in the low-pressure chamber by the air delivery device, the dry ice particles are jetted onto the surface to be cleaned in the low-pressure chamber, and the adhering matter adhering to the surface to be cleaned is removed by the collision energy generated by the injection. It is characterized by that.

In the deposit removal method according to the present invention, the air sent out by the air delivery device is compressed air.
By doing in this way, dry ice grain can be injected by the compressed air produced | generated by compressing the air taken in in the low pressure room | chamber interior. When compressed air is jetted, the flow rate is fast, so that dry ice particles can be jetted at high speed.

In the deposit removal method according to the present invention, the air delivery device is a compressor.
Thus, by using a compressor as an air delivery device, compressed air can be generated and dry ice particles can be injected. Moreover, since this compressor is installed indoors, the deposit | attachment adhering to the to-be-cleaned surface can be removed, without raising the pressure in a low pressure room | chamber very much.

In the deposit removal method according to the present invention, the air is dedusted before being taken in the low pressure chamber.
As described above, since the dust is removed before the air is taken in, the attached matter after the removal does not flow into the inside of the delivery device. For example, deposits such as asbestos do not enter the compressor. Therefore, there is no need to clean the inside of the compressor.

In the deposit removal method according to the present invention, the deposit is an deposit containing asbestos, dioxin, or a radioactive substance.
Since this method is performed in a low-pressure room whose pressure is lower than the outside air pressure, the outside air flows into the room. Therefore, even if the deposits are harmful substances that are harmful to the human body and cannot be leaked to the outside, such as asbestos, dioxin, or radioactive substances, they should not leak to the outside. Can do.

  As described above, since the air sending device sends out the air taken in while taking in the air in the low-pressure chamber, the amount of air taken in and the amount of air sent out are almost the same in average during the removal work of the deposits. It becomes. Then, since the indoor air amount is kept substantially constant, the indoor air pressure is kept constant (low pressure). In other words, the pressure inside the room does not increase like the high-pressure compressed air sent from the outdoor compressor, so there are many negative pressure dust collectors to keep the room at a lower pressure than the outside air pressure, There is no need to install a negative pressure dust collector. Therefore, it is possible to remove deposits attached to the wall surface at a low cost in a room maintained at a pressure lower than the external pressure.

  Embodiments of a deposit removal method and a deposit removal apparatus will be described below with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a schematic configuration of a deposit removing device in the present embodiment. FIG. 2 is a diagram for explaining a method of removing the deposits in the present embodiment. The present embodiment is used in a workplace where the atmospheric pressure needs to be maintained at a lower pressure than the outdoor in order to prevent harmful substances from leaking outside. Here, a method for removing asbestos harmful to the human body attached to the wall surface will be described.

  The removal apparatus in the present embodiment is installed in the room 6 maintained at a pressure lower than the outdoor pressure (atmospheric pressure). Therefore, here, the isolated sealed curing of the room 6 is first performed by the isolated sealed curing step S31. The isolated and sealed curing is a work for curing the work place so as to be sealed against the outside air in order to create a work space having a lower atmospheric pressure than the outdoor. Therefore, here, a sheet made of PET (PET sheet) is pasted and cured so as to block the indoor 6 and the outdoor passage. Then, the air from the room 6 does not flow out of the room, and the asbestos 7 and dust are prevented from flowing out of the room.

  In FIG. 1, the window 15 and the entrance / exit 16 can be the air flow path to the outside of the room. Therefore, the PET sheet 11 is pasted around the window 15 so as to completely block the air flow path to the outside as an isolated hermetic curing. A PET sheet 11 is also provided at the doorway 16 of the worker. However, here, a small air flow path is provided between the outside air and the room 6 by attaching the PET sheet 11 like a curtain. This is because indoor air is sucked out by a negative pressure dust collector 21 described later, so that outside air can be taken in and the atmospheric pressure in the room 6 does not become lower than necessary. The air flow path formed between the entrance / exit 16 and the PET sheet 11 is a small flow path that allows the interior 6 to be maintained at a moderately low pressure when the negative pressure dust collector 21 is operated. It has become. In this way, curing is performed to create the room 6 having a lower atmospheric pressure than the outdoor atmospheric pressure.

  A negative pressure dust collector 21 is installed outside the room. The negative pressure dust collector 21 sucks the air inside the isolated sealed curing chamber 6, filters the air with a filter, removes harmful substances contained in the air, and exhausts the air outside the chamber 6. Thus, the negative pressure dust collector 21 sucks the air in the room 6 that is isolated and sealed and cured, so that the atmospheric pressure in the room is reduced to the atmospheric pressure outside the room. Further, the indoor air is sucked by the negative pressure dust collector 21, whereby carbon dioxide after sublimation of dry ice, which will be described later, is discharged.

  Next, a removing device is installed in the room 6 (S32). The removal device in the present embodiment stores the dry ice grains 5 that are input, and sequentially feeds the dry ice grains 5, and a compressor that generates compressed air for injecting the dry ice grains 5. 8 is provided. The dry ice transport machine 2 includes a dry ice mixing unit 14 and a hopper 20. Further, the compressor 8 used in the present embodiment is a small compressor having a size that can be installed in a low-pressure chamber. The discharge port of the compressor 8 is connected to the dry ice mixing unit 14 via a connection hose 18.

  By the way, after the room is brought into a low pressure state, the amount of air discharged from the negative pressure dust collector 21 to the outside and the amount of air flowing in from the gap such as the PET sheet 11 are kept substantially the same. The low pressure state is maintained. Therefore, it can be considered that the amount of air in the room 6 is substantially the same as the amount of air when sealed in a low pressure state. In the case of continuously removing the deposits, the compressor discharges the compressed air while compressing the taken-in air into the tank. In this case, the amount of air taken in per unit time by the compressor 8 installed in the low-pressure chamber 6 and the amount of discharged air are substantially the same. If it does so, the air quantity in the room | chamber 6 will be kept substantially constant, and a low-pressure state will be maintained also during the removal operation | work of a deposit. In other words, various compressors can be used as long as the amount of air taken in per unit time is approximately the same as the amount of air discharged (or a compressor with a larger amount of air that can be taken up per unit time than the amount of air that can be discharged). Types of compressors can be used.

  The small compressor 8 in the present embodiment has a tank capacity for storing compressed air smaller than that of the large compressor. Therefore, the air discharge port is narrowed down so that the pressure in the tank does not drop rapidly. In this case, the small compressor discharges less air per unit time than the large compressor. If the amount of air discharged per unit time is small, even if the discharged air is compressed air, it is difficult to increase the pressure in the low-pressure chamber immediately after the start of injection. For a small compressor, even if the discharge rate per unit time of air is increased, due to the small tank capacity, the low-pressure chamber is increased to an atmospheric pressure equivalent to the external pressure. This is convenient because it cannot be used for the room 6.

  Therefore, it is desirable to install a small compressor in the room. The compressor 8 used here has a discharge capacity of 48 (L / min). The compressor 8 can discharge air at a maximum pressure of 0.67 (MPa).

  The removing device includes an injection nozzle 3 that injects the dry ice particles 5 stored in the dry ice transporter 2 toward the asbestos 7 on the wall surface 17 that is the surface to be cleaned by the wind pressure from the compressor 8. The spray nozzle 3 is attached to the dry ice mixing unit 14 by a spray hose 4.

  A dust filter 10 is attached to the air intake port 9 of the compressor 8 via a connection hose 13 as a device for removing dust. Since the compressor 8 takes in air, an air flow is formed in a direction from the room toward the air intake 9. Therefore, asbestos flying in the air as dust gets on this flow and is collected by the dust removal filter 10. Thus, since the dust removal filter 10 is attached to the air intake port 9 of the compressor 8 via the connection hose 13, the inside of the compressor 8, the inside of the injection hose 4, and the injection nozzle 3 are not contaminated by harmful substances. . And it is not necessary to wash | clean these inside after completion | finish of the asbestos removal operation | work.

  In addition to the dust filter 10, as a device for removing dust, a solid-gas separation device such as a cyclone may be attached so that asbestos flying in the air can be more actively collected.

  The dry ice transporter 2 has a hopper 20 for storing the supplied dry ice grains 5 and a dry ice mixture for transporting the dry ice grains 5 supplied from the hopper to the injection nozzle 3 by mixing with the compressed air. Part 14 is included. A hopper 20 as a dry ice supply device is disposed in the upper part of the dry ice transporter 2. The hopper 20 is a device that temporarily stores the supplied dry ice grains 5 and carries out a necessary amount to the dry ice mixing unit 14. The lower side of the hopper 20 has a funnel shape, and the supply amount of the dry ice particles 5 to the dry ice mixing unit 14 is controlled by a supply adjusting device attached to the funnel-shaped tip. This supply adjusting device is, for example, a screw-like member cut in a spiral shape. Then, by rotating the screw-like member, the dry ice particles 5 that have entered the groove portion of the screw upper member are sequentially supplied to the dry ice mixing unit 14.

  In the dry ice mixing unit 14, the dry ice particles 5 supplied from the hopper 20 are mixed with the compressed air and sent to the injection hose 4 side. The dry ice particles 5 put into the hopper 20 are formed into a cylindrical shape having a diameter of 3 mm and a length of 10 mm.

  The above-described spray hose 4 is attached to the spray nozzle 3. And the dry ice grain 5 can be injected with compressed air. The sprayed dry ice particles 5 collide with the asbestos 7 on the wall surface, and the asbestos 7 is peeled off by the collision energy. The dry ice particles 5 are sprayed as an abrasive and efficiently remove the asbestos 7 that is a deposit from the surface to be cleaned. The dry ice particles 5 after the asbestos 7 is removed from the wall surface 17 disappears as carbon dioxide by the sublimation action. Therefore, only the asbestos 7 that has been peeled off remains after the asbestos 7 is removed. In addition, when dry ice is used, the work space is cooled, which has the advantage of being a summer heat stroke countermeasure.

  When the removing device as described above is installed, asbestos removal work is performed using the removing device (S33). As described above, when the compressed air is sent by the compressor 8, the dry ice particles 5 are sent out by the compressed air and jetted from the jet nozzle 3. And the asbestos 7 of a wall surface is peeled and removed. This removal operation is performed while the spray nozzle 3 is supported manually. However, this may be performed by an automated machine.

  In addition, the compressor 8 in this embodiment is an illustration as an air sending-out apparatus. Therefore, the present invention is not limited to this as long as it is a device that can take in air and send out air at a flow rate sufficient to remove deposits. When the air delivery device other than the compressor is used and the pressure of the delivery air is weak, it is possible to generate high-pressure air by increasing the air flow rate through the pipe using a funnel-shaped throttle member. .

  Further, when a device having a high air intake capability is used as the air delivery device, dust removal may be performed using this air intake capability. At this time, a separate hose may be attached to the other side of the dust filter 10 to which the connection hose 13 is attached, and the removed deposits may be collected via this hose. By doing so, the suction force of the air delivery device is used, and the asbestos 7 removed on the wall surface 17 of the room 6 is sucked.

  In this embodiment, the dry ice particles 5 are put into the dry ice transporter 2 by an operator. However, the room 6 may be provided with a liquefied carbon dioxide tank and a dry ice production device (pelletizer). Then, the asbestos 7 may be removed while the dry ice grains 5 described above are manufactured in the room 6. Further, the dry ice grains 5 are not necessarily formed into a cylindrical shape, and may be formed into any shape as long as they are in a pellet shape. Further, instead of the PET sheet 11, a curing sheet may be used.

  In addition, here, the explanation was made by taking the removal work of asbestos 7 adhering to the wall surface as an example, but the situation where the work place needs to be lower than the external pressure to prevent harmful substances from leaking outside. It can also be used to remove other underlying harmful substances.

  For example, it can be used for cleaning a pool side wall stocked with spent nuclear fuel. Since spent nuclear fuel continues to release heat after being taken out of the furnace, it is stored in a pool filled with water for a while after use. When the temperature of spent nuclear fuel drops and these are removed from the pool, the pool wall is drained and the pool wall is cleaned. Since this pool is for storing radioactive substances, it is a sealed space. In such a space, it is easy to create a room having an atmospheric pressure lower than the external atmospheric pressure as described above. Further, the dirt on the wall surface to be removed is a harmful substance containing a radioactive substance and cannot be leaked to the outside. Therefore, the above-described removal method can be used when cleaning the pool wall surface. And the stain | pollution | contamination containing the radioactive substance of a wall surface can be removed at low cost.

  This removal method can also be used in incinerators of garbage incineration facilities, flues, dust collectors, inner walls of chimneys, railway tunnel walls, silos, garbage pits, storage containers for radioactive materials, etc. It can also be used in places where ash, soot, dust, storage soot, filth, contaminants, soil, labels, seals, coating materials, etc. are attached.

It is a figure which shows schematic structure of the removal apparatus in this embodiment. It is a figure for demonstrating the asbestos removal method in this embodiment.

Explanation of symbols

2 Dry ice transport machine, 3 spray nozzle, 4 spray hose, 5 dry ice grains,
6 indoors, 7 asbestos, 8 compressors, 9 intakes,
10 dust filter, 11 PET sheet, 13 connecting hose,
14 Dry ice mixing section, 15 windows, 16 doorway, 17 wall surface,
18 connection hose, 20 hopper, 21 negative pressure dust collector,
S31 curing process, S32 removal device installation process, S33 asbestos removal process

Claims (5)

A sheet is affixed around the window, and the door is provided with a curtain-like sheet to provide an air flow path between the room and the outside.
By sucking indoor air and exhausting it to the outside of the room, the room is made into a low-pressure room having an atmospheric pressure lower than the outside air pressure,
The air delivery device installed in the low-pressure chamber sends out the air taken in the low-pressure chamber, thereby spraying dry ice particles onto the surface to be cleaned in the low-pressure chamber, and the surface to be cleaned by the collision energy generated by the injection. An attached matter removing method, wherein the attached attached matter is removed.   The deposit removal method according to claim 1, wherein the air sent out by the air delivery device is compressed air.   The deposit removal method according to claim 1, wherein the air delivery device is a compressor.   The deposit removal method according to any one of claims 1 to 3, wherein the air is dedusted before being taken in the low pressure chamber.   The said deposit | attachment is a deposit containing asbestos, dioxin, or a radioactive substance, The deposit | attachment removal method in any one of Claims 1-4 characterized by the above-mentioned.

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