Patent Document

BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a blasting apparatus and a blasting method for ejecting blasting media to a surface to be treated and roughening the surface to be treated to perform surface preparation.  
         [0003]     2. Description of the Related Art  
         [0004]     In the suppression chamber of an atomic power plant facility, the frame is made of concrete, and a pool is constructed by pasting steel plates on its inner wall surface and bottom surface. The outer surface of the steel plates, namely the inner surface of the suppression chamber is coated by recoating it with a plurality of coating materials excellent in corrosion resistance, decontaminability and the like. The repainting construction is carried out with about  10  years after the start of operation as a guide, and as a pre-construction of the repainting construction, a blasting operation of grinding the coating film including radioactive substances on the inner surface and roughening the coated surface to perform surface preparation is performed.  
         [0005]     The blasting operation is performed by a sand blasting technique as described in Japanese Patent Application Laid-Open No. 9-109029. The sand blasting technique is a technique of causing a blast material such as sand ejected from a nozzle by high speed air to collide against a coated surface and grinding the coating film on the coated surface with the impact force to roughen the surface.  
         [0006]     However, in the sand blasting technique, the blast material rebounds with a strong force, and therefore, there is the problem of scattering of dust particles. There is also the disadvantage that a worker who operates a nozzle has to be heavily equipped to protect his or her body from the blast material that rebounds with a strong force, which impairs workability. Further, it is difficult for the worker to perform the operation with uniform quality because he or she has a poor view due to scattering dust particles.  
         [0007]     Thus, in order to solve such problems, the applicant of the present application proposes a technique of using a blast medium in a sponge piece form with abrasives contained in a porous elastic body, namely, a sponge blasting technique.  
         [0008]     According to the sponge blasting technique, when a sponge blast medium ejected from a nozzle with high speed air collides against a coated surface, the blast medium becomes flat, and the contained abrasives directly collide against the coated surface at a high speed. Thereby, the coating film can be ground and removed as in the sand blasting technique. Dust particles which usually float in the air are taken into the sponge pieces and directly drop, and therefore, there is the advantage of being capable of reducing scattering of dust particles. Further, since the repulsive force is also absorbed by the sponge pieces, rebound is drastically reduced, and thereby, there is provided the advantage that the worker who operates the nozzle can be lightly equipped.  
         [0009]     Incidentally, roughness of the roughened coated surface of the suppression chamber is specified in accordance with the coating material to be coated. Therefore, a worker selects the abrasive of the material corresponding to the roughness, and the worker treats the coated surface to desired roughness as the worker manually repeats the blasting operation and roughness measurement.  
       SUMMARY OF THE INVENTION  
       [0010]     However, the above described conventional blasting operation of the suppression chamber is the operation of manually performing the blasting operation and roughness measurement, which depends on the intuition of a worker, and therefore, there is the demand for standardization and automation of the blasting operation.  
         [0011]     The present invention is made in view of the above circumstances, and has its object to provide a blasting apparatus and a blasting method capable of achieving standardization and automation in a blasting operation of a surface to be treated of which roughness is specified.  
         [0012]     In order to attain the above-described object, the invention according to a first aspect of the present invention is a blasting apparatus which is provided with an ejection device, which ejects blast media, and a recovery device, which sucks and recovers ejected and used blast media, on a traveling carriage, ejects the blast media to a surface to be treated by the ejection device while causing the traveling carriage to travel on the surface to be treated, and recovers the used blast media by the recovery device, and is characterized by including a roughness measuring device that is provided at the traveling carriage and measures roughness of an uneven surface of the surface to be treated which is treated by ejection of the blast media, and a control unit which performs a feedback control of an ejection amount of the blast media, ejection pressure, ejection speed, an ejection air amount, a suction air amount by the recovery device, and a speed of the traveling carriage so that the roughness which is measured by the roughness measuring device is within a range of predetermined roughness.  
         [0013]     To attain the above described object, the invention according to a fourth aspect of the present invention is, in a blasting method in which an ejection device which ejects blast media, and a recovery device which sucks and recovers ejected and used blast media are provided on a traveling carriage, the blast media is ejected to a surface to be treated by the ejection device while causing the traveling carriage to travel on the surface to be treated, and the used blast media are recovered by the recovery device, characterized by including the steps of measuring roughness of an uneven surface of the surface to be treated which is treated by ejection of the blast media, and performing a feedback control of an ejection amount of the blast media, ejection pressure, ejection speed, an ejection air amount, a suction air amount by the recovery device, and a speed of the traveling carriage so that the roughness which is measured is within a range of predetermined roughness.  
         [0014]     According to the invention described in the first and fourth aspects, the ejection device of the blast media, the recovery device of the blast media, and the roughness measuring device are mounted on the traveling carriage which travels and moves on the surface to be treated. Then, the traveling carriage is caused to automatically travel, and while the blast media are ejected to the surface to be treated from the ejection device, and the used blast media are sucked and recovered by the recovery device, the roughness (the arithmetic average roughness, the maximum height, the ten point height of irregularities) of the uneven surface of the surface to be treated which is treated by ejection of the blast media is measured by the roughness measuring device. Then, the feedback control of the ejection amount of the blast media, the ejection pressure, the ejection speed, the ejection air amount, the suction air amount by the above described recovery device, and the speed of the above described traveling carriage is performed so that the measured roughness is within the range of predetermined roughness. Thereby, standardization and automation can be achieved in the blast operation of the surface to be treated of which roughness is specified.  
         [0015]     If the various conditions to achieve the predetermined roughness obtained by the above described feedback control are stored in the storage part of the control unit, and are read at the next time of using the same conditions, the surface to be treated can be treated to have the predetermined roughness from the beginning without performing a feedback control at the next time.  
         [0016]     In the first aspect, the invention described in a second aspect is characterized by further including an image pickup device which is provided at the traveling carriage and picks up an image of the surface to be treated which is treated by ejection of the blast media, and in that the control unit compares an image obtained by the image pickup device and a reference image which is previously stored, and determines a rust removal degree of the surface to be treated and/or an anchor pattern.  
         [0017]     In the fourth aspect, the invention described in a fifth aspect is characterized by further including the steps of picking up an image of the surface to be treated which is treated by ejection of the blast media, comparing the image with the reference image, and determining the rust removal degree of the surface to be treated and/or an anchor pattern According to the invention described in the second and fifth aspects, the image pickup device is provided at the traveling carriage, the image of the surface to be treated after blasting is picked up by the image pickup device, and the control unit compares the image obtained by the image pickup device and the reference image (sample image) previously stored, and determines the rust removal degree of the surface to be treated specified by ISO and/or the anchor pattern. Therefore, according to the present invention, the blasting operation of the surface to be treated and the rust removal degree determining operation and/or the anchor pattern determining operation can be simultaneously carried out.  
         [0018]     In the first or the second aspect, the invention described in a third aspect is characterized in that the blast medium is a blast medium in which abrasives are contained in a porous elastic body.  
         [0019]     In the fourth or the fifth aspect, the invention described in a sixth aspect is characterized in that the blast medium is a blast medium in which abrasives are contained in a porous elastic body.  
         [0020]     The invention described in the third and sixth aspects is characterized in that the blast medium is a blast medium in which abrasives are contained in a porous elastic body.  
         [0021]     The invention described in the third and sixth aspects is characterized by adopting a blasting technique which uses the blast media in which abrasives are contained in porous elastic bodies as the blast media. The blast media used in the blasting technique is what is made by containing abrasives of different materials in accordance with use purpose in porous elastic bodies such as sponge, the blast media are ejected to the coated surface by high pressure air, grind the coated surface and roughen the surface.  
         [0022]     According to the blasting technique, when the blast media collide against the coated surface, the blast media become flat, and the abrasives contained therein directly collide against the coated surface at a high speed. Thereby, as in a sand blasting technique, the coated surface can be ground by the abrasives. Dust particles which usually float in the air are taken into the porous elastic bodies and directly drop, and therefore, scattering of dust particles can be prevented. Since the repulsive force is absorbed by the porous elastic bodies, rebound does not occur, and therefore, equipment of a worker can be light.  
         [0023]     According to the blasting apparatus and blasting method of the present invention, the ejection device of the blast media, the recovery device of the blast media and the roughness measuring device are mounted on the traveling carriage which travels and moves on the surface to be treated, then the traveling carriage is caused to travel automatically, and while the blast media are ejected to the surface to be treated from the ejection device, and the used blast media are sucked and recovered by the recovery device, the roughness of the uneven surface of the surface to be treated which is treated by ejection of the blast media is measured by the roughness measuring device. Then, a feedback control of the ejection amount of the blast media, the ejection pressure, the ejection speed, the ejection air amount, the suction air amount by the above described recovery device, and the speed of the above described traveling carriage is performed so that the measured roughness is within the range of the predetermined roughness, and therefore, in the blasting operation of the surface to be treated of which roughness is specified, standardization and automation can be achieved. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a general schematic diagram of a sponge blasting apparatus;  
         [0025]      FIGS. 2A  to  2 C are views explaining a mechanism of the sponge blasting;  
         [0026]      FIG. 3  is a view explaining equipment of a worker of the sponge blasting;  
         [0027]      FIG. 4  is a sectional view of a blasting apparatus of an embodiment; and  
         [0028]      FIG. 5  is a block diagram showing a construction of the blasting apparatus shown in  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]     A preferred embodiment of a blasting apparatus and a blasting method according to the present invention will now be described in detail with reference to the accompanying drawings.  
         [0030]      FIG. 1  is an explanatory view showing a basic structure of a sponge-shaped porous elastic body blasting apparatus (hereinafter, called a sponge blasting apparatus)  20 .  
         [0031]     Explaining a sponge blasting technique using the sponge blasting apparatus  20  first, a blast medium  26  used in this technique is made by sticking abrasives (also called a grinding material in the case of a urea resin) of a different material (steel grit, alumina, star light, a urea resin and the like) in accordance with the roughness (arithmetic average roughness, maximum height, ten point height of irregularities), which is required of a coated surface  30 , to a sponge piece  24  as shown in  FIGS. 2A  to  2 C. In this technique, the blast media  26  are ejected to a coating film  28  on a wall  40  by high pressure air, grind the coating film  28  and roughen the coated surface  30  to perform surface preparation.  
         [0032]     According to the sponge blasting technique, when the blast media  26  collide against the coating film  28  as shown in  FIG. 2A , the blast media  26  become flat as shown in  FIG. 2B , and the abrasives  22 ,  22  contained therein directly collide against the coating film  28  at a high speed. Thereby, as in the sand blasting technique, the coating film  28  can be ground as in  FIG. 2C . Dust particles  32 ,  32 , which usually float in the air, are taken into the sponge pieces  24  and directly drop, and therefore, scattering of dust particles can be prevented. Further, the repulsive force is also absorbed by the sponge pieces  24 , and therefore, there is less rebound of the blast media  26 .  
         [0033]     Therefore, equipment  36  of a worker  34  who operates the sponge blasting apparatus  20  can be light as shown in  FIG. 3 .  FIG. 3  shows a view of the worker  34  holding a hose  39  in the vicinity of a nozzle  38  of the sponge blasting apparatus  20  with both hands, and ejecting the blast media  26  to the wall  40 . The worker  34  does not have to equip his or her entire body with a protector as in a sand blasting technique, and as for a helmet  42 , an ordinary helmet used in a working site with a face protector  43  formed of a transparent acrylic sheet mounted thereon is used instead of a full-face type helmet which covers all the head portion and the face portion, and the equipment  36  is made extremely light. Thereby, the weight of the equipment is light, and therefore, labor of the worker  34  can be significantly reduced.  
         [0034]     The sponge blasting apparatus  20  is constructed by a sponge blast supply device  50 , a compressor  52 , a nozzle  38 , a recovery device  54 , a recycle separator  56  and a hopper  58 , as shown in  FIG. 1 .  
         [0035]     High pressure air is supplied from the compressor  52  and blast media  26  (see  FIG. 2A ) is supplied from the hopper  58  to the sponge blast supply device  50 . The blast media  26  are ejected to the wall  40  at a high speed from a tip end of the nozzle  38  by being transported by air via the hose  39  by the high pressure air from the compressor  52 . The blast media  26  used for grinding directly drop onto a sheet S in a state in which dust particles  32 ,  32  (see  FIG. 2C ) are taken therein, are sucked into the recovery device  54  through a hose  61  from a suction port  60  of the recovery device  54 , and fed into the recycle separator  56 .  
         [0036]     The recycle separator  56  is constructed by stacking two sieves  62 ,  64 , which respectively have sieve openings of large and medium sizes, in layer on a vibration generator  66 . The blast media  26  are first fed into the sieve  62  with the large sieve openings, and the sieve  62  is vibrated by the vibrator of the vibration generator  66 , whereby the large-sized blast media  26  are separated and taken out from the sieve  62 . The blast media  26  which pass through the sieve  62  drop into the sieve  64 , and the medium-sized blast media  26  are separated and taken out by the sieve  64  which is similarly vibrated by the vibrator. The large-and medium-sized blast media  26  removed from the sieves  62  and  64  can be used as they are, and therefore, they are conveyed to the hopper  58 . Fine blast media  26  which pass through the sieve  64  are not reusable, and therefore, stored in a container  68  and discarded. Reusable blast media  26  constitute about 90% of the entire blast media  26 . The above is the basic structure of the sponge blasting apparatus  20 .  
         [0037]      FIG. 4  is a sectional view of a blasting apparatus  70  according to an embodiment, the same or similar members as in the sponge blasting apparatus  20  shown in  FIG. 1  to  FIG. 3  are described by assigning them with the same reference numerals.  
         [0038]     An apparatus body  72  of the blasting apparatus  70  is a traveling carriage including a front wheel  74  and a rear wheel  76  of a permanent magnet, and by magnetically attaching the front wheel  74  and the rear wheel  76  to the coated surface  30  of a steel plate, the apparatus body  72  is mounted to be capable of traveling and moving along the coated surface  30 . In the embodiment, the front wheel  74  and the rear wheel  76  are made of the permanent magnet, but they may be of an electromagnet.  
         [0039]     Further, rubber seal members  78  are fixed to opening end portions of the apparatus body  72 , and the seal members  78  are caused to abut on the coated surface  30  with elasticity, whereby the internal space  73  of the apparatus body  72  is sealed. Thereby, the blast media  26  ejected in the internal space  73  is prevented from leaking out of the apparatus body  72 .  
         [0040]     Further, a pressure sensor  80  which detects internal pressure of the internal space  73  is mounted to the apparatus body  72 , and the information indicating the pressure detected by the pressure sensor  80  is outputted to a CPU (control unit)  82  shown in  FIG. 5 . The CPU  82  is a central processing unit which has a centralized control over the entire blasting apparatus  70  such as the sponge blast supply device  50 , the compressor  52 , the recovery device  54  and the like. The CPU  82  will be described later.  
         [0041]     As shown in  FIG. 4 , the apparatus body  72  is provided with the nozzle  38  and the suction port  60  to penetrate through the internal space  73 . When the apparatus body  72  is magnetically attached to the coated surface  30 , the nozzle  38  and the suction port  60  are opposed to the coated surface  30 , and the blast media  26  are ejected to the coated surface  30  from the nozzle  38  while the used blast media  26  which collide against the coated surface  30  are sucked and recovered from the suction port  60 .  
         [0042]     Probe type roughness meters (roughness measuring devices)  84  and  84  which measure the roughness of the uneven surface of the coated surface  30  which is ground by ejection of the blast media  26  are provided at a front portion and a rear portion of the apparatus body  72 . The information indicating the roughness measured by the roughness meter  84  is outputted to the CPU  82  shown in  FIG. 5 . When the apparatus body  72  is moved upward, the information indicating roughness measured by the roughness meter  84  at the rear portion is outputted to the CPU  82 , and when the apparatus body  72  is moved downward, the information indicating the roughness measured by the roughness meter  84  at the front portion is outputted to the CPU  82 . In the embodiment, an example of the probe (contact) type roughness meter  84  is shown, but the roughness meter is not limited to this, and a non-contact type roughness meter may be applied.  
         [0043]     The roughness meters  84  and  84  are provided at the apparatus body  72  via advancing and retreating devices  86  and  86  as shown in  FIG. 4 , and only at the time of measurement, they are advanced toward the coated surface  30  and brought into contact with the coated surface  30 . The advancing and retreating devices  86  and  86  are also controlled by the CPU  82 , and a motor  88  (not shown in  FIG. 4 , shown in  FIG. 5 ) which drives the front wheel  74  and/or the rear wheel  76  is also remotely controlled by the CPU  82 . The advancing and retreating devices  86  and  86  and the motor  88  are supplied with power from a cable  83  shown in  FIG. 4 , and the cable  83  is inserted into the hose  85  connected to the apparatus body  72 . The cable  83  may be placed along the hoses  39  and  61  without using the hose  85 .  
         [0044]     Meanwhile, the apparatus body  72  is provided with an electronic camera  90  which picks up an image of the coated surface  30  ground by ejection of the blast media  26 . The image data of the coated surface  30  picked up by the electronic camera  90  is outputted to the CPU  82  in  FIG. 5 . The CPU  82  compares the image obtained by the electronic camera  90  and a reference image (sample image) previously stored, and determines the rust removal degree of the coated surface  30  and the pattern of the stripped plane (anchor pattern).  
         [0045]     Next, an operation of the blasting apparatus  70  constructed as above will be described.  
         [0046]     First, the apparatus body  72  on which the nozzle  38 , the suction port  60 , the pressure sensor  80 , the roughness meters  84  and the electronic camera  90  are mounted is magnetically attached to the coated surface  30  via the front wheel  74  and the rear wheel  76  of the permanent magnet.  
         [0047]     Next, by driving the front wheel  74  and/or the rear wheel  76  by the motor  88 , the apparatus body  72  is caused to travel upward automatically, and while the blast media  26  are ejected to the coated surface  30  from the nozzle  38  and the used blast media  26  are sucked and recovered by the suction port  60 , roughness (arithmetic average roughness, maximum height, ten point height of irregularities) of the uneven surface of the coated surface  30  ground by the ejection of the blast media  26  is measured by the roughness meter  84 .  
         [0048]     The CPU  82  controls at least one of the sponge blasting supply device  50 , the compressor  52 , the recovery device  54  and the motor  88  so that the measured roughness is within a range of predetermined roughness corresponding to the coating, and performs a feedback control of at least one of an ejection amount of the blast media  26 , ejection pressure, ejection speed, an ejection air amount, a suction air amount, and speed of the apparatus body  72 .  
         [0049]     Thereby, according to the blasting apparatus  70  of the embodiment, in the blasting operation of the coated surface  30  of which roughness is specified, standardization and automation can be achieved.  
         [0050]     The various conditions to make the predetermined roughness obtained by the above described feedback control are stored in a storage part of the CPU  82 . The various conditions are read from the storage part and used at the next time when the next same conditions are used. Thereby, at the time of the next operation, the coated surface  30  can be treated to have predetermined roughness from the beginning without performing a feedback control.  
         [0051]     Further, the CPU  82  compares the coated surface image after a blast operation which is picked up by the electronic camera  90  of the apparatus body  72 , and the reference image (sample image) previously stored, and the rust removal degree of the coated surface  30  specified by ISO and the anchor pattern are determined. The rust removal degree and the anchor pattern are determined by comparing gradations of the images, for example. Therefore, according to the blasting apparatus  70  of the embodiment, the blasting operation of the coated surface  30 , and the rust removal degree determining operation and/or the anchor pattern determining operation can be simultaneously performed The determination result by the CPU  82  may be outputted from a printer or may be displayed on a display.  
         [0052]     Since the blasting apparatus  70  is for performing a blasting operation while moving on the coated surface  30  up and down, an over blast phenomenon in which portions which overlap the adjacent coated surface are ground more than the other portions sometimes occurs, and distribution sometimes occurs to roughness. In order to prevent this problem, in the blasting apparatus  70  of the embodiment, the number of blast media  26  which are ejected to the overlapping portions is made smaller than that of the blast media  26  ejected to the central portion, and adjustment is made so that the same amount is blasted to each portion as a result.  
         [0053]     After the blasting apparatus  70  moves upward, when the blasting apparatus is to move downward, the front wheel  74  and/or the rear wheel  76  which are magnetically attached are or is operated with a handle (not shown), and the overlapping regions of the coated surface  30  last surface) to be ground can be made as small as possible.  
         [0054]     In the embodiment, the sponge blast medium  26  in which abrasives are contained in the porous elastic body is described as the blast medium, but the blast medium is not limited to this, and may be a sand blast medium.

Technology Category: 7