JP5003959B2 - Blasting device and operation method thereof - Google Patents

Description

  The present invention relates to a blasting apparatus and a method for operating the blasting apparatus, and in particular, a blasting apparatus mainly for removing a coating film on a wall surface of a nuclear power plant facility or decontaminating a ground surface from which a coating film has been removed, and It relates to the driving method.

  In recent years, regarding the decommissioning of nuclear power plant facilities, legislation has been put in place regarding dismantling standards for such decommissioning. When dismantling the reactor facilities, it is necessary to prevent the diffusion of radioactive materials. If the base material is painted, first remove the coating film containing radioactive material on the wall, and then contaminate the substrate (base material) from which the coating film has been removed (radioactive radioactive contamination). Need to be removed (decontaminated).

  The present applicant has proposed a blasting apparatus in Patent Document 1 for the purpose of removing a coating film containing such a radioactive substance and decontaminating the ground surface.

  The blasting apparatus of Patent Document 1 uses a blast medium in which an abrasive is fixed in a porous elastic body (sponge), projects the blast medium toward a painted wall surface, removes the coating film, and removes the ground surface. Decontamination is performed. According to this blasting apparatus, when the blasting medium collides with the coating film, the blasting medium becomes flat and the fixed abrasive directly collides with the coating film at high speed. Can be removed by grinding. In addition, since dust that normally floats in the air is taken into the porous elastic body and falls as it is, dust scattering can be prevented. Due to such advantages, there is a specific effect that the working environment can be greatly improved as compared with a sandblasting apparatus in which dust is drifted in a large amount in the working environment.

  By the way, the dry blasting apparatus disclosed in Patent Document 1 mainly uses a blasting medium in which a hard abrasive such as alumina or zirconia is fixed to a porous elastic body. It can be carried out. However, when cleaning the substrate, a wet blasting device that uses a liquid blasting medium containing abrasive in water, even when using a low-hardness abrasive (such as a polishing material) such as urea resin. In other words, the cleaning efficiency is inevitably inferior to that of an apparatus for washing out contaminants with a liquid.

FIG. 1 of Patent Document 2 shows a wet blasting apparatus that supplies abrasive material to a steam water mixing nozzle of a steam injector including a water nozzle and a steam nozzle, and grinds an oxide film of a workpiece and a metal base material. It is disclosed. In this blasting apparatus, compressed air mixed with steam water and an abrasive are pressure-fed into a building buried pipe of a nuclear facility to grind an oxide film and a metal base material on the inner surface of the pipe.
JP 2006-130618 A JP 2000-75095 A

  Since the wet blasting apparatus of Patent Document 2 can wash away contaminants with water, it can be said that the cleaning efficiency is higher than that of the dry blasting apparatus of Patent Document 1. However, since the wet blasting apparatus as in Patent Document 2 is basically an apparatus that mainly performs water cleaning, there is a problem that rust is generated by returning to the cleaned ground surface. In addition, since it is based on water washing, it is difficult to reliably remove (decontaminate) contamination on the ground surface.

  Such a problem can be solved by a blasting apparatus that uses a powder blast medium, mixes an alkaline liquid with the powder blast medium, and projects the mixed medium from a nozzle through a hose. However, such a blasting device has a problem that the mixed medium is a fluid having a high viscosity, so that it is clogged particularly in the nozzle during air conveyance in the hose. When the mixed medium is clogged, the amount of projection of the mixed medium varies, so that the projection cannot be performed stably.

  The present invention has been made in view of such circumstances, and a blasting apparatus capable of stably projecting a mixed medium obtained by mixing a powdered blasting medium and a liquid from a nozzle through a hose and its operation. It aims to provide a method.

  In order to achieve the object, the invention of the operation method of the blasting apparatus according to claim 1 is a tank in which a powder blast medium is stored and a blast medium supply port is formed, and the supply of the tank. A hose with a base end connected to the mouth, a nozzle connected to the tip of the hose, a compressed air supply unit for supplying compressed air to the base end of the hose, and a base end of the hose A liquid supply unit that supplies liquid toward the blast medium supplied from the supply port of the tank, a pressure sensor that detects an internal pressure of the hose, and a replenisher supply unit that supplies replenisher to the nozzle And selecting a blasting medium to be used from among a plurality of blasting media, determining a projection amount per hour of the selected blasting medium, and selecting the blasting medium. A suitable mixing ratio of the blasting medium and the liquid mixed in the blasting medium is determined and the mixing ratio is stored in a control unit, and the control unit is configured to control the blasting apparatus so as to obtain the suitable mixing ratio. The blast medium supply amount by the blast medium supply unit and / or the liquid supply amount by the liquid supply unit are controlled, and the replenishment liquid supply means is controlled based on the internal pressure of the hose detected by the pressure sensor to perform the replenishment The liquid is supplied / stopped to the nozzle.

  In order to achieve the object, the invention of the operation method of the blasting apparatus according to claim 4 includes a tank in which a powdery blast medium is stored and a supply port for the blast medium is formed, and the supply of the tank. A hose with a base end connected to the mouth, a nozzle connected to the tip of the hose, a compressed air supply unit for supplying compressed air to the base end of the hose, and a base end of the hose A liquid supply unit that supplies liquid toward the blast medium supplied from the supply port of the tank, a pressure sensor that detects an internal pressure of the hose, and a replenisher supply unit that supplies replenisher to the nozzle A blasting medium to be used is selected from among a plurality of blasting media, and a projection amount per hour of the selected blasting medium is determined and selected. A suitable mixing ratio between the blasting medium and the liquid mixed with the blasting medium is determined, and the mixing ratio is stored in the control unit. The blast medium supply amount by the blast medium supply unit and / or the liquid supply amount by the liquid supply unit are controlled, and the replenisher supply means is controlled based on the internal pressure of the hose detected by the pressure sensor to thereby supply the replenisher solution. Is supplied / stopped to the nozzle.

  First, the focus of the present invention will be described.

  If the mixed medium is clogged in the nozzle during the projection of the mixed medium, the projection amount fluctuates as described above, but the internal pressure of the hose also fluctuates in conjunction with this. That is, when the mixed medium is clogged, the internal pressure of the hose increases rapidly as compared with that during normal projection. That is, the focus of the present invention is to determine the state of projection by detecting the internal pressure of the hose, and when the internal pressure of the hose becomes higher than the specified value, the mixed medium is clogged in the nozzle. In this case, the replenisher is supplied to the nozzle to lower the viscosity of the mixed medium, and the clogging of the mixed medium in the nozzle is immediately resolved.

  According to the first and fourth aspects of the invention based on this point of view, the pressure sensor for detecting the internal pressure of the hose and the replenisher supply means for supplying the replenisher to the nozzle are provided. A blast medium to be used is selected, and a projection amount per hour of the selected blast medium is determined. Next, a suitable mixing ratio between the selected blast medium and the liquid mixed in the blast medium is determined, and the mixing ratio is stored in the control unit. The control unit controls the blast medium supply amount by the blast medium supply unit and / or the liquid supply amount by the liquid supply unit of the blasting device so as to obtain a suitable mixing ratio, and the hose detected by the pressure sensor. Based on the internal pressure, the replenisher supply means is controlled to supply / stop the replenisher to the nozzle. That is, the control unit determines that the mixed medium is clogged in the nozzle when the internal pressure of the hose becomes higher than the specified value. At this time, the replenisher is supplied to the nozzle, Eliminate clogging of mixed media immediately. Thereby, according to invention of Claim 1, this invention, the mixed medium which mixed the powdery blasting medium and the liquid can be stably projected from a nozzle through a hose. The specified value is an empirical value corresponding to the capability of the blasting device.

  When calcium carbonate powder is selected as the blast medium, the mass ratio, which is the mixing ratio of calcium carbonate powder (specific gravity: about 1.55 kgf / l) and liquid (specific gravity: about 1.00 kgf / l), is 6 : Control to 1 to 4: 1. As a result, the liquid can be entangled with the calcium carbonate powder satisfactorily, and the calcium carbonate powder can be prevented from being scattered due to the excessive liquid, and the liquid can be prevented from being individually projected due to the excessive liquid.

  By using pulverized shells such as scallops as the calcium carbonate powder, a powdery blasting medium suitable for protecting global environmental resources can be obtained. The calcium carbonate powder may be industrially produced, or may be fixed to a sponge piece to form a sponge blast medium.

  In addition, when silica sand, especially No. 7 silica sand (specific gravity: about 1.38 kgf / l) is selected as the blasting medium, the mass ratio which is the mixing ratio of the silica sand and the liquid (specific gravity: about 1.00 kgf / l) is It is controlled to 4: 1-3: 1. Thereby, the liquid can be entangled with the silica sand well, and the scattering of the silica sand due to the excessive liquid can be prevented, and the single projection of the liquid due to the excessive liquid can be prevented.

  The invention described in claim 2 is characterized in that, in claim 1, the liquid and the replenisher are alkaline electrolyzed water mixed with a surfactant, and the hydrogen ion concentration thereof is pH 12 or more. .

  The invention according to claim 5 is characterized in that, in claim 4, the liquid and the replenisher are alkaline electrolyzed water mixed with a surfactant, and the hydrogen ion concentration thereof is pH 12 or more. .

  According to the second and fifth aspects of the present invention, since alkaline electrolyzed water is used as the liquid mixed in the blast medium and the replenisher, it is possible to suppress the occurrence of return rust on the ground surface on which the mixed medium is projected. it can. Moreover, since the hydrogen ion concentration of the alkaline electrolyzed water is set to pH 12 or more, a high effect can be obtained for preventing the ground rust from returning. Furthermore, the contamination adhering to the substrate can be removed (decomposes the dirt) by the surfactant mixed in the alkaline electrolyzed water. Therefore, a high decontamination effect can be obtained.

  A third aspect of the present invention provides the pH measuring means for measuring the hydrogen ion concentration of the liquid and the replenishing liquid according to the first or second aspect, wherein the hydrogen ion concentration measured by the pH measuring means is pH 11 When the value is less than the value, the control means controls the alkali supply means to control the hydrogen ion concentration of the liquid and the replenisher to pH 11 or more.

  A sixth aspect of the present invention provides the pH measurement means for measuring the hydrogen ion concentration of the liquid and the replenishing liquid according to the fourth or sixth aspect, wherein the hydrogen ion concentration measured by the pH measurement means is pH 11 When the value is less than the value, the control means controls the alkali supply means to control the hydrogen ion concentration of the liquid and the replenisher to pH 11 or more.

  According to the third and sixth aspects of the invention, since the hydrogen ion concentration of the liquid and the replenisher solution decreases with time, this is monitored by the pH measuring means, and when the hydrogen ion concentration becomes less than pH11. The control means controls the alkali supply means to supply an alkali solution such as sodium hydroxide and a surfactant to the liquid and replenisher, and always maintain the liquid and replenisher at a pH of 11 or more, preferably 12 or more. As a result, the properties and components of the liquid and the replenisher can be maintained at all times, so that a stable effect can be exhibited in preventing return rust and decontamination.

  The powder form described in this specification refers to a powder having a diameter of 0.01 mm or less.

  According to the blasting apparatus and the operation method thereof according to the present invention, when the internal pressure of the hose becomes higher than a specified value, the control unit determines that the mixed medium is clogged in the nozzle. Since the replenisher was supplied to the nozzle and the clogging of the mixed medium in the nozzle was immediately resolved, the mixed medium in which the powdered blast medium and liquid were mixed was stabilized from the nozzle through the hose. Can project.

  Hereinafter, preferred embodiments of a blasting apparatus and an operation method thereof according to the present invention will be described in detail according to the accompanying drawings.

  A blasting apparatus 10 of the embodiment shown in FIG. 1 is a blasting apparatus used for decontamination of the ground 14 from which the coating film on the wall surface 12 of the nuclear power plant facility has been removed. FIG. 2 is an explanatory diagram showing the main structure of the blasting apparatus 10 and the blocks of the control system.

  First, the decontamination method using the blasting apparatus 10 will be described. The medium used in this decontamination method is a powdered calcium carbonate powder 16 that is a blasting medium and a liquid (a surfactant is mixed in alkaline electrolyzed water). The liquid 18 is a mixed medium 20 in which the liquid 18 is not separated independently but soaks into the calcium carbonate powder 16, and the calcium carbonate powder 16 is wet with the liquid 18. . This mixed medium 20 is projected onto the ground surface 14 with compressed air at a high speed to decontaminate the ground surface 14.

  According to this blasting device 10, when the mixed medium 20 collides with the ground surface 14, the calcium carbonate powders 16, 16. The ground 14 is adjusted by this impact force, and the contamination adhering to the ground 14 is removed (decontaminated) by the liquid 18 like water washing. In addition, since dust that normally floats in the air is taken into the mixed medium 20 and falls as it is, dust scattering can also be prevented. Furthermore, since the repulsive force is also absorbed by the liquid 18, the mixed medium 20 hardly bounces. Due to such characteristics, the equipment of the operator 22 handling the blasting device 10 as shown in FIG.

  FIG. 1 shows a diagram in which the operator 22 holds the hose 26 near the nozzle 24 of the blasting apparatus 10 with both hands and projects the mixed medium 20 toward the ground 14. The worker 22 is lightly equipped without the need to equip the entire body with a protector unlike the sandblasting method. Thereby, the labor of the operator 22 is significantly reduced.

  2 includes a tank 28, a blast medium supply device 30, a hose 26, a nozzle 24, an air compressor 32, a liquid supply unit 38 including a liquid tank 34, a flow rate adjusting valve 36, and the like.

  The tank 28 stores the calcium carbonate powder 16 as a blast medium, and a supply port 29 for the calcium carbonate powder 16 is formed below the hopper portion 28A. The tank 28 is a direct pressure tank to which pressure is applied by compressed air from the air compressor 40.

  The hose 26 has a predetermined length, a base end portion 26 </ b> A is connected to a supply port 29 of the tank 28 via a joint pipe 42, and a nozzle 24 is connected to a tip end portion 26 </ b> B of the hose 26.

  The air compressor 32 is connected to the joint pipe 42, and supplies compressed air to the base end portion 26 </ b> A of the hose 26 through the joint pipe 42.

  As described above, the liquid supply unit 38 includes the liquid tank 34 and the flow rate adjustment valve 36, and the liquid 18 stored in the liquid tank 34 is connected to the base end portion 26 </ b> A of the hose 26 via the flow rate adjustment valve 36. Is supplied through. Further, by controlling the opening degree and opening / closing of the flow rate adjusting valve 36 by the control unit 44 described later, the supply amount of the liquid 18 and ON / OFF of the liquid supply are controlled.

  The liquid 18 in the liquid tank 34 is pumped at a pressure (0.1 to 0.5 MPa relative to the internal pressure of the tank 28) by an airless pump 35, and ON / OFF lever 37 is manually or automatically turned on / off. Further, the backflow of the liquid 18 is prevented by a check valve 39 disposed on the downstream side of the flow rate adjustment valve 36.

  The supply position of the liquid 18 in the joint pipe 42 is set to the downstream end position of the blast medium supply device 30. As a result, the liquid 18 is supplied to the calcium carbonate powder 16 supplied from the supply port 29 and sent out by the blast medium supply device 30.

  The blast medium supply device 30 is a screw provided in the joint pipe 42 along the horizontal axis direction of the joint pipe 42. When the blast medium supply device 30 is driven to rotate, the calcium carbonate powder 16 stored in the tank 28 is forcibly scraped from the supply port 29 by a screw and guided to the base end portion 26 </ b> A of the hose 26. The calcium carbonate powder 16 guided to the base end portion 26 </ b> A of the hose 26 is mixed with the liquid 18 to become the mixed medium 20 and is pumped from the hose 26 toward the nozzle 24 by the compressed air from the air compressor 32. Is done. Then, the liquid 18 is mixed with the calcium carbonate powder 16 in a stage before being effectively mixed by the compressed air while being fed by the hose 26 and projected from the nozzle 24. In order to generate such a mixed medium 20, the supply amount of the calcium carbonate powder 16 by the blast medium supply device 30 and the supply amounts of the liquid 18, the internal pressure of the tank 28, and the pressure by the air compressor 32 are suitable values. Respectively. The blast medium supply device 30 may be disposed vertically below the supply port 29 of the tank 28 along the axis of the hopper portion 28A.

  Next, the operation of the blasting apparatus 10 configured as described above will be described.

  The basic operation of the blasting apparatus 10 is to mix calcium carbonate powder and the liquid 18 on the base end portion 26A side of the hose 26, and to mix the mixed medium 20 of the mixed blast medium 16 and the liquid 18 with compressed air. The inside of the hose 26 is pneumatically transported and projected from the nozzle 24 at the tip of the hose 26 toward the ground 14. That is, the mixed medium 20 is accelerated from the base end portion 26 </ b> A of the hose 26 and is projected from the nozzle 24 toward the substrate 14 at a high speed.

  Therefore, the mixed medium 20 is projected without being decelerated at the position of the nozzle 24. Further, since the mixing area becomes longer by passing the calcium carbonate powder 16 and the liquid 18 through the hose 26, the mixing of the calcium carbonate powder 16 and the liquid 18 is performed reliably and effectively. . Due to this mixing action, the liquid 18 is satisfactorily soaked into the calcium carbonate powder 16, so that the liquid 18 is not directly projected from the nozzle 24, and the calcium carbonate powder 16 soaked with the liquid 18 is projected from the nozzle 24.

  By the above operation, generation of dust due to the projected calcium carbonate powder 16 can be suppressed, and contamination of the ground surface 14 is removed by water 18 soaked in the calcium carbonate powder 16 like water washing. Dyeing can be carried out efficiently. Moreover, since the liquid 18 is infiltrated into the calcium carbonate powder 16 and is not projected by the liquid 18 alone, generation of secondary waste (water) can be suppressed.

  On the other hand, the used mixed medium 20 dropped by blasting becomes a lump because the liquid 18 is entangled. Thereby, it becomes easy to collect compared with water. Further, since the collected mixed medium 20 contains contamination (radioactive contaminants), it is preferable to store it in a cask and store it in an existing radiation control area. This eliminates the need for a secondary waste water treatment facility as compared with water containing radioactive pollutants, and makes handling of waste much easier.

  In the embodiment, powdery calcium carbonate powder 16 is used as the blasting medium. However, if the calcium carbonate powder 16 has a high hardness (for example, Mohs hardness of 6 or more), it is difficult to grind the coating film. Work can be done. Further, if the hardness is low (for example, less than Mohs hardness 6), soft work such as decontamination work or mirror finishing can be performed as in the embodiment. Furthermore, by using a pulverized shell such as scallop as the calcium carbonate powder 16, a powdery blasting medium suitable for protecting global environmental resources can be obtained. The calcium carbonate powder 16 may be industrially produced.

  By the way, the blasting apparatus 10 that handles the mixed medium 20 has a problem that the mixed medium 20 is a fluid having a high viscosity, so that it is clogged particularly in the nozzle 24 during air conveyance in the hose 26. When the mixed medium 20 is clogged in the nozzle 24, the projection amount of the mixed medium 20 varies, so that the projection cannot be performed stably.

  Therefore, in order to eliminate the above problems, the blasting apparatus 10 according to the embodiment has a pressure sensor 46 for detecting the internal pressure of the hose 26 and a replenisher supplying part (replenisher) for supplying the replenisher 48 to the nozzle 24 as shown in FIG. Supply means) 50.

  According to this blasting apparatus 10, first, a blasting medium to be used (for example, calcium carbonate powder 16) is selected from among a plurality of blasting media, and a projection amount per hour (for example, 7 kgf / min) of the selected blasting medium is selected. decide. Next, a suitable mixing ratio between the selected blast medium and the liquid 18 mixed with the blast medium is determined, and the mixing ratio is stored in the control unit 44.

  Then, the control unit 44 controls the blast medium supply amount by the blast medium supply device 30 and / or the liquid supply amount by the liquid supply unit 38 of the blasting device 10 and a pressure sensor 46 so as to obtain a suitable mixing ratio. The replenisher supply unit 50 is controlled based on the internal pressure of the hose 26 detected by the above operation to supply / stop the replenisher 48 to the nozzle 24.

  That is, the control unit 44 determines that the mixed medium 20 is clogged in the nozzle 24 when the internal pressure of the hose 26 becomes higher than the specified value, and supplies the replenisher 48 to the nozzle 24 at this time. Thus, the clogging of the mixed medium in the nozzle 24 is immediately resolved. Thereby, according to this blasting apparatus 10, the mixed medium 20 which mixed the powdery calcium carbonate powder 16 and the liquid 18 can be stably projected from the nozzle 24 via the hose 26. The specified value is an empirical value corresponding to the capability of the blasting apparatus 10.

  Specifically, the replenisher supply unit 50 includes a replenisher tank 52 in which the replenisher 48 is stored, a pump 54 that pumps the replenisher 48 to the nozzle 24, and a valve 56 that supplies / stops the replenisher 48. It is configured. The control unit 44 controls the opening and closing of the valve 56 based on the internal pressure of the hose 26 from the pressure sensor 46. That is, when the internal pressure of the hose 26 exceeds a specified value, the valve 56 is opened to supply the replenisher 48 to the nozzle 24. When the hose 26 falls below the specified value, the valve 56 is closed and the replenisher 48 is supplied. Stop.

  FIG. 3 is a graph showing the change over time in the hose internal pressure. The vertical axis shows the hose internal pressure (MPa), and the horizontal axis shows the projection time (t).

  According to the figure, the hose internal pressure is maintained at a constant value during normal operation when the nozzle 24 is not clogged, but when the nozzle 24 is clogged, the hose internal pressure rapidly increases. When the internal pressure of the hose reaches the replenisher supply pressure (specified value), the replenisher 48 is supplied to the nozzle 24. Thereby, the clogging of the nozzle 24 is eliminated, the hose internal pressure is lowered, and a constant value is maintained.

  When calcium carbonate powder 16 is selected as the blasting medium 16, the mixing ratio of calcium carbonate powder (specific gravity: about 1.55 kgf / l) 16 and liquid (specific gravity: about 1.00 kgf / l) 18 is used. The mass ratio is controlled to 6: 1 to 4: 1. As a result, the liquid 18 can be entangled with the calcium carbonate powder 16 satisfactorily, and the calcium carbonate powder 16 can be prevented from being scattered due to an excess of liquid, and the single projection of the liquid 18 due to an excess of liquid can be prevented.

  Moreover, by using a pulverized shell such as scallop as the calcium carbonate powder 16, a powdery blasting medium suitable for protecting global environmental resources can be obtained. The calcium carbonate powder 16 may be industrially produced, or the calcium carbonate powder 16 may be fixed to a sponge piece to form a sponge blast medium.

  Further, when silica sand, especially No. 7 silica sand (specific gravity: about 1.38 kgf / l) is selected as the blasting medium, the mass ratio which is a mixing ratio of the silica sand and the liquid (specific gravity: about 1.00 kgf / l) 18 Is controlled to 4: 1 to 3: 1. As a result, the liquid 18 can be entangled well with the silica sand, so that the silica sand can be prevented from being scattered due to an excess of liquid, and the single projection of the liquid 18 due to an excess of liquid can be prevented.

  On the other hand, the liquid 18 and the replenisher 48 are alkaline electrolyzed water mixed with a surfactant, and the hydrogen ion concentration is set to pH 12 or higher.

  Since alkaline electrolyzed water is used as the liquid 18 mixed in the calcium carbonate powder 16 as described above, it is possible to suppress the occurrence of return rust on the ground 14 on which the mixed medium 20 is projected. Further, since the hydrogen ion concentration of the alkaline electrolyzed water is set to pH 12 or more, a high effect can be obtained in preventing the ground surface 14 from returning to rust. Furthermore, the contamination adhering to the substrate can be removed (decomposes the dirt) by the surfactant mixed in the alkaline electrolyzed water. Therefore, a high decontamination effect can be obtained. As the surfactant, it is preferable to use TFD4 (product name, manufactured by FRANKLAB) having a high action of removing radioactive contamination. The pH of the TFD4 stock solution is 13.5, and the pH at 10% dilution is 12.5.

  In the blasting apparatus 10, pH sensors (pH measuring means) 58 and 60 for measuring the hydrogen ion concentration of the liquid 18 and the replenishing liquid 48 are provided in the liquid tank 34 and the replenishing liquid tank 52. When the hydrogen ion concentration measured by the pH sensors 58 and 60 becomes less than pH 11, the control unit 44 controls the alkali supply units (alkali supply means) 62 and 64 to control the hydrogen in the liquid 18 and the replenisher 48. The ion concentration is controlled to pH 11 or higher.

  That is, since the hydrogen ion concentration of the liquid 18 and the replenisher 48 decreases with time, this is monitored by the pH sensors 58 and 60. When the hydrogen ion concentration becomes less than pH 11, the controller 44 supplies the alkali. The units 62 and 64 are controlled, and an alkaline solution such as sodium hydroxide and / or a surfactant is supplied to the liquid 18 and the replenisher 48, and the liquid 18 and the replenisher 48 are always maintained at a pH of 11 or more, preferably 12 or more. is doing.

  As a result, the properties and components of the liquid 18 and the replenisher 48 can be maintained at all times, so that stable effects can be exhibited in preventing rust and decontamination.

  The alkali supply units 62 and 64 supply the alkali solution and / or the surfactant to the liquid tank 34 by the tank 66 storing the alkali solution and / or the surfactant and the control unit 44 controlling opening and closing. And a valve 70 for supplying an alkaline solution and / or a surfactant to the replenisher tank 52 when the controller 44 controls the opening and closing thereof.

  Note that the blasting apparatus 10 of the embodiment can also be used in the coating film removal process performed before the decontamination process of the substrate 14. In this case, it is preferable to use an abrasive such as copper slag (calami), steel grit, alumina, zirconia, etc. having high hardness as the blast medium.

  Below, an example of the manufacturing method of alkaline electrolyzed water is shown.

  First, tap water is put into a water conditioner. Next, a calcium agent (calcium lactate or the like) is dissolved in tap water. Thereby, while ionizing into a calcium ion and a hydroxide ion, water is also slightly ionized and it separates into a hydrogen ion and a hydroxide ion. Next, when electricity is applied and voltage is applied to start electrolysis, hydrogen ions and calcium ions are attracted to the cathode (minus electrode), thereby producing alkaline electrolyzed water. At this time, the hydrogen ion at the cathode receives an electron and becomes a hydrogen atom, and further, two of the atoms are combined to form a hydrogen molecule (gas).

Explanatory drawing which showed the whole structure of the blasting apparatus of embodiment Explanatory drawing which showed the principal part structure of the blasting apparatus shown in FIG. Graph showing changes in hose pressure over time

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Blast apparatus, 12 ... Wall surface of nuclear power plant equipment, 14 ... Ground surface, 16 ... Calcium carbonate powder, 18 ... Liquid, 20 ... Mixed medium, 22 ... Worker, 24 ... Nozzle, 26 ... Hose, 28 ... Tank, 30 ... Blasting medium supply device, 32 ... Air compressor, 34 ... Liquid tank, 36 ... Flow control valve, 38 ... Liquid supply unit, 40 ... Air compressor, 42 ... Joint pipe, 44 ... Control unit, 46 ... Pressure sensor 48 ... Replenisher solution, 50 ... Replenisher supply unit, 52 ... Replenisher tank, 54 ... Pump, 56 ... Valve, 58 ... pH sensor, 60 ... pH sensor, 62 ... Alkali supply unit, 64 ... Alkali supply unit, 66 ... tank, 68 ... valve, 70 ... valve

Claims (6)

A tank in which a powdery blast medium is stored and a supply port for the blast medium is formed; a hose having a base end connected to the supply port of the tank; and a nozzle connected to a tip of the hose; A compressed air supply unit that supplies compressed air to the base end of the hose; and a liquid that is connected to the base end of the hose and supplies liquid toward the blast medium supplied from the supply port of the tank In an operation method of a blasting apparatus comprising a supply unit, a pressure sensor that detects an internal pressure of the hose, and a replenisher supply unit that supplies replenisher to the nozzle,
Select the blast medium to be used from among the multiple blast media, determine the projection amount per hour of the selected blast medium,
Determining a suitable mixing ratio between the selected blast medium and the liquid to be mixed with the blast medium, and storing the mixing ratio in the control unit;
The control unit controls the blast medium supply amount by the blast medium supply unit of the blast device and / or the liquid supply amount by the liquid supply unit so as to achieve the preferable mixing ratio, and is detected by the pressure sensor. A method of operating a blasting apparatus, wherein the replenisher supplying means is controlled based on the internal pressure of the hose to supply / stop the replenisher to the nozzle.   The method for operating a blasting apparatus according to claim 1, wherein the liquid and the replenisher are alkaline electrolyzed water mixed with a surfactant, and the hydrogen ion concentration thereof is pH 12 or higher.   PH measurement means for measuring the hydrogen ion concentration of the liquid and the replenisher is provided, and when the hydrogen ion concentration measured by the pH measurement means is less than pH 11, the control means controls the alkali supply means, The method for operating a blasting apparatus according to claim 1 or 2, wherein the hydrogen ion concentration of the liquid and the replenisher is controlled to be 11 or more. A tank in which a powdery blast medium is stored and a supply port for the blast medium is formed; a hose having a base end connected to the supply port of the tank; and a nozzle connected to a tip of the hose; A compressed air supply unit that supplies compressed air to the base end of the hose; and a liquid that is connected to the base end of the hose and supplies liquid toward the blast medium supplied from the supply port of the tank In a blasting apparatus comprising a supply unit, a pressure sensor for detecting an internal pressure of the hose, and a replenisher supply unit for supplying a replenisher to the nozzle,
A blast medium to be used is selected from among a plurality of blast media, and a projection amount per hour of the selected blast medium is determined.
A suitable mixing ratio between the selected blast medium and the liquid mixed in the blast medium is determined, and the mixing ratio is stored in the control unit;
The control unit controls the blast medium supply amount by the blast medium supply unit of the blast device and / or the liquid supply amount by the liquid supply unit so as to achieve the preferable mixing ratio, and is detected by the pressure sensor. A blasting apparatus characterized in that the replenisher supply means is controlled based on the internal pressure of the hose to supply / stop the replenisher to the nozzle.   The blasting apparatus according to claim 4, wherein the liquid and the replenisher are alkaline electrolyzed water mixed with a surfactant, and a hydrogen ion concentration thereof is pH 12 or more.   PH measurement means for measuring the hydrogen ion concentration of the liquid and the replenisher is provided, and when the hydrogen ion concentration measured by the pH measurement means is less than pH 11, the control means controls the alkali supply means, The blasting apparatus according to claim 4 or 5, wherein a hydrogen ion concentration of the liquid and the replenisher is controlled to be pH 11 or more.

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