JP6067722B2 - Mixed air jet blasting method and apparatus - Google Patents

Description

  The present invention is a blasting treatment that mainly performs surface treatment such as rust prevention and roughening of various structures such as ships, bridge piers, sheet piles for revetment, etc. using steel materials, or coating film peeling, dirt removal, washing, etc. The present invention relates to a mixed-air jet blasting method and apparatus for injecting compressed gas and high-pressure water in a mixed state including a polishing material.

  Conventionally, the sandblasting method has been used in coatings and rust removal on surfaces of various structures such as ships, bridge piers, and revetment sheet piles, as well as ground treatment for painting.

  However, in the sandblasting method, a fine-grained polishing material (for example, a steel grid) is sprayed with compressed air to remove rust or prevent rust on the surface of the object to be processed and to roughen the surface. Is. However, in this case, the abrasive that is sprayed with the compressed air collides with the surface of the object to be processed and is scattered to generate dust, which requires time and effort for cleaning after the processing operation. There is a problem that the working environment and the surrounding environment deteriorate due to dust, which adversely affects the human body and harms the health. Furthermore, the used abrasives become waste sand and generate industrial waste.

  Further, as an alternative to the sand blasting method, for example, a water blasting method using only high-pressure water or a combination of high-pressure water and a cleaning material has been developed. Was developed.

  However, although the above-mentioned ultra-high pressure water blasting method is optimal for removing or cleaning the surface of the object to be treated, it does not allow the new roughening required as a base treatment for coating and is relatively short after the treatment. There is a problem that rusting occurs with time. Even in the case of the water blasting method using a polishing material, there is a problem that the effect of roughening as a ground treatment is not so high, and the use of water causes return rust.

  Further, in recent years, compressed gas (compressed air or the like) and high-pressure water are supplied to the injection nozzle portion through the respective supply passages, mixed by the injection nozzle, and the surface of the object to be processed is blasted as a jet-like injection flow. In this case, an air-jet jet blasting method for performing a blasting process such as cleaning by providing a supply part of the granular material in a part of the supply path of the compressed gas and making the jet flow in a mixed state including the granular material And the apparatus for it is proposed (patent documents 1-5).

  However, all of the proposed mixed-air jet blasting methods are mainly used for cleaning the surface of an object to be cleaned such as a wall surface of a car or a building, a basket, tableware, etc. The purpose is to enhance the cleaning effect of the cleaning object, and as a result, the effect of roughening as a base treatment before coating is hardly obtained. In addition, there is no substitute for using water, and there is a problem that rust is generated in a relatively short time after the treatment.

  Moreover, in the water blasting process in which the blasting material is blasted together with the water, it has been proposed to use zinc particles as the scouring material as metal particles that are lower than iron in order to prevent return rust ( Patent Document 6), a sufficient graining effect cannot be obtained, and a large amount of expensive zinc particles are used, resulting in high cost.

JP 2001-029847 A JP 2002-178262 A Japanese Patent Application Laid-Open No. 2002-079145 JP 2002-011387 A JP 2006-123141 A JP 2001-046957 A

  The present invention was made to solve the above-mentioned conventional problems, solve the problems of the conventional sand blasting method, the water blasting method and the ultra-high pressure water blasting method, rust removal and roughening work, It is an object of the present invention to provide a mixed-air jet blasting method and apparatus capable of unifying cleaning operations such as removal of dirt and suppressing the occurrence of return rust.

In the mixed-air jet blasting method of the present invention, a gas supply path for supplying compressed gas from a compressed gas supply source to the injection nozzle unit, and high-pressure water from the liquid supply source to the injection nozzle unit via a high-pressure pump. A liquid supply path, and the compressed gas fed by the gas supply path and the high-pressure water fed by the liquid supply path are mixed in the spray nozzle unit and sprayed from the nozzle tip toward the object to be processed, In the mixed- air jet blasting method for the steel material for blasting the surface of the object to be processed, a polishing material supply device for roughening the object to be processed is connected to a part of the gas supply path, the Institute cleaning agent consisting of metal particles or metal other inorganic particles, is pumped by mixing a predetermined amount by compressed gas, injected with mixed jet of the compressed gas and high pressure water from the injection nozzle unit, this time Rust back into the mixed jet flow And baking soda to prevent the mixed state characterized by injection.

  Thereby, by the mixed jet flow of compressed gas and high-pressure water containing an abrasive consisting of metal particles or inorganic particles other than metal, it is possible to effectively perform rust removal work such as peeling of deposits and rust removal, and By using the abrasive, roughing work can be done at the same time. Moreover, since baking soda for preventing return rust is mixed and sprayed in the mixed jet stream, the surface of the object to be treated which has been subjected to derusting and roughening can be protected with a film of alkaline baking soda, Occurrence of return rust due to oxidation can be suppressed.

  In the mixed air jet blasting method, to the polishing material mixed into the compressed gas from the polishing material supply device, sodium bicarbonate having a particle size of 500 microns or less is added and mixed in a ratio of 2 to 10% by weight, and the mixing is performed. It is preferable to inject in the state which mixed sodium bicarbonate with the injection stream.

  That is, when the particle size of the baking soda exceeds 500 microns, it becomes difficult to adhere to the surface of the abrasive. In addition, if the particle size is too small, it becomes difficult to handle. Therefore, it is preferable to use a baking soda having a particle size of 5 microns or more and 500 microns or less, particularly 100 microns or less. Moreover, when the mixing ratio of the baking soda is less than 2% by weight, the amount of adhesion to the surface of the granular scouring material is small, and the effect of preventing the return rust caused by adding and mixing the baking soda to the scouring material and spraying is small. Further, increasing the amount of baking soda increases the cost despite the fact that the rust-preventing effect is hardly changed, so it is preferable that the amount be 2 to 10% by weight.

  Further, in the mixed-air jet blasting method according to the present invention, instead of adding baking soda to the polishing material, mixing sodium bicarbonate in advance in a ratio of 2 to 10% by weight as high-pressure water to be fed to the spray nozzle unit. The diluted water can be used and sprayed in a state where sodium bicarbonate is mixed into the mixed jet stream. Thereby, the mixing state of the baking soda in the said mixed injection flow is equalized, and the return rust prevention of the to-be-processed object surface is made effectively.

  When used as diluting water for baking soda, if the mixing ratio of baking soda to water is less than 2% by weight, the effect of preventing return rust by mixing and injecting baking soda will be small. However, since it becomes difficult to dilute the baking soda into water, the content is preferably 2 to 10% by weight as described above.

  In the mixed-air jet blasting method, the grain size of the abrasive is 100 to 2000 microns. That is, when the grain size of the abrasive is smaller than 100 microns, the effect of removing rust and roughening of the object to be treated is small, and the muddy abrasive is attached and takes time to clean. On the other hand, when the particle size exceeds 2000 microns, the surface of the object to be processed becomes rough and the air-jet nozzle may be clogged. Therefore, the grain size of the abrasive is preferably in the above range.

The mixed-air jet blasting apparatus of the present invention feeds high-pressure water from a supply source of compressed gas to a jet nozzle unit through a gas supply path that feeds compressed gas to the jet nozzle unit and a pump device from the liquid supply source. An injection nozzle that mixes the liquid supply path, the compressed gas supplied by the gas supply path and the high-pressure water supplied by the liquid supply path, and injects the mixed compressed gas and high-pressure water toward the workpiece. and a section, a admission jet blast apparatus for steel, performs the gas supply passage is connected to a part of the, eye Do Ri object to be processed from the inorganic particles other than the metal particles or metal rubbing blast A cleaning material supply device for mixing a material into the compressed gas by a predetermined amount is provided, and the gas supply path or the liquid supply path is provided as a supply path for supplying sodium bicarbonate for preventing return rust to the injection nozzle unit. The spray nozzle part is Characterized by comprising is configured to be injected while mixing the sodium bicarbonate to a mixed jet of the compressed gas and the high pressure water the Research cleaning agent is mixed.

In the mixed-air jet blasting apparatus, in addition to the liquid supply path for supplying high-pressure water to the injection nozzle unit , the liquid supply path for supplying high-pressure water to the fume cleaning nozzle that injects only high-pressure water, and the high-pressure water to the washing nozzle The liquid supply path for supplying water is provided, and the supply of high-pressure water to each liquid supply path can be switched according to the nozzle to be used.

  Further, in the mixed-air jet blasting apparatus, opening / closing of an on-off valve provided in the gas supply path for supplying / stopping compressed gas, operation of the supply device for the abrasive, operation of the pump device, and liquid supply It can be provided with a control unit for controlling the opening and closing of the opening and closing valves provided in the road.

  As described above, according to the mixed-air jet blasting method and apparatus of the present invention, it is possible to solve the problems of the conventional sandblasting method, the waterblasting method and the ultra-high pressure water blasting method, and the mixed jet flow of compressed gas and high pressure water. In addition, it is possible to efficiently perform the rust removal and graining work of the steel structure by including the abrasive containing the metal particles or the inorganic particles other than the metal in the compressed gas. In addition, by mixing and injecting baking soda to prevent rusting in the mixed jet stream, the blasting process allows the object to be treated despite the use of water. The surface can be protected by an alkaline baking soda film, and the occurrence of return rust after treatment can be suppressed. Moreover, since sodium bicarbonate is mixed and used to prevent return rust, the treated water is discharged as it is without causing pollution problems.

It is the schematic which shows the whole structure of the mixed-air jet blasting apparatus used for implementation of this invention. FIG. 6 is a schematic explanatory view of a blasting state by a mixed jet flow including a polishing material from an air-jet nozzle.

  Next, an embodiment of the present invention will be described based on an example shown in the drawings together with a schematic configuration of the apparatus.

  FIG. 1 shows a mixed-air jet blasting apparatus A used in the practice of the present invention. In FIG. 1, various types of nozzles including an apparatus main body 1, an abrasive supply device 2, and an air-jet nozzle, such as a fume cleaning nozzle 7-1, an air-jet nozzle 7-2, and a water washing nozzle 7-3. It is comprised from the injection nozzle part provided with nozzles, such as. Reference numerals 7-1a, 7-2a, and 7-3a in the figure indicate the tip of each nozzle.

  The apparatus main body 1 includes a liquid tank 4 that temporarily stores liquid such as tap water and sodium bicarbonate diluted water supplied through a filter 15 on the liquid supply source side, and the pressure from the liquid tank 4 is increased to, for example, 75 MPa by a high-pressure pump 5. The liquid is depressurized through the distributor 9 directly or with the regulators 11-2 and 11-3 according to the use of each of the plurality of nozzles 7-1, 7-2 and 7-3. Are connected to a plurality of liquid supply paths 6-1, 6-2, 6-3 and connected to the nozzle side hose via the liquid supply paths 6-1, 6-2, 6-3. 8-1, 8-2, and 8-3. Each of the liquid supply paths 6-1, 6-2, 6-3 is provided with opening / closing valves 10-1, 10-2, 10-3 that are opened / closed according to the nozzles to be used. Moreover, the apparatus main body 1 is provided with the control part 17 which can change the quantity of the nozzle change and the abrasives according to a use.

  The abrasive supply device 2 provided in the gas supply path 3 for feeding compressed air is connected to compressed air of 0.7 Mpa or less, preferably 0.3 to 0.7 Mpa, and is connected to an open / close valve 18 via an air filter 16. Is supplied to the gas supply path 3, and the compressed air is supplied to the mixed-air jet nozzle 7-2 through the gas supply path 3. The supply device 2 is provided with a supply tank 12 having a relatively large capacity, for example, a capacity capable of supplying a polishing material for several hours. The supply tank 12 is provided with a delivery device 13 capable of delivering a predetermined amount of abrasive according to a signal from the control unit 17, and baking soda is placed in a pipe line portion of the gas supply passage 3 downstream from the open / close valve 18. The added and mixed abrasive is fed in a predetermined amount and mixed with compressed air, and the abrasive mixture gas is supplied to the connecting portion 19 with the hose on the nozzle side. Reference numeral 14 denotes an opening / closing valve provided in a delivery path from the supply tank 12.

  As the polishing material, steel grids conventionally used as this type of polishing material, various metal particles such as zinc particles, or various inorganic particles such as silica sand can be used, especially when scouring copper. A so-called copper slag in which the resulting slag is sized can be suitably used. In addition, the apparatus main body 1 and the abrasive supply device 2 may be integrated or separated depending on the capacity.

  When the polishing material fed to the supply tank 12 does not use baking soda diluted water for high-pressure water, for example, baking powder is added to and mixed with the polishing material such as copper slag in advance. Of course, it is not impossible to add and mix sodium bicarbonate powder in the supply tank 12, but in practice, in a separate process, the mixture is mixed using a mixer (not shown) equipped with a mixer, and this is added to the supply tank 12. It is preferable to supply from the viewpoint of mixing efficiency and the like.

  The mixed gas jet nozzle 7-2 includes a compressed gas containing an abrasive material fed through the gas supply path 3, that is, an abrasive mixture gas, and high-pressure water fed from the liquid supply path 6-2 through a hose. Are mixed in the nozzle body and jetted as a jet-like mixed jet stream from the nozzle tip 7-2a. As the internal structure, a known mechanism can be used as this kind of the mixed-air jet nozzle, and therefore detailed description thereof is omitted here.

  The apparatus main body 1 is a mixed-air jet nozzle 7 for removing rust, preventing rust and coarsening by mixing and injecting compressed gas and high-pressure water to the connecting portion 8-2 of the liquid supply path 6-2. -2 in addition to the liquid supply passages 6-1 and 6-3 and the connection portions 8-1 and 8- 3 and a fume washing nozzle 7-1 connected to these connecting portions 8-1 and 8-3 and a water washing nozzle 7-3 can be provided together. Accordingly, the liquid supply to the liquid supply paths 6-1, 6-2, 6-3 can be switched. Furthermore, although illustration is abbreviate | omitted, the spray nozzle only for coating film peeling instead of an air-fuel | gaseous jet nozzle may be provided in the connection part 8-2 so that connection is possible.

  As means for connecting the nozzles 7-1, 7-2 and 7-3 to the connection parts 8-1, 8-2 and 8-3, a coupling that can be attached and detached with one touch and other sealing states are maintained. Various connection structures that can connect pipes can be used. Further, a plurality of nozzles may be connected and switched by only opening and closing the valve.

  The apparatus main body 1 includes an opening / closing valve 18 provided in the gas supply path 3 for supplying / stopping compressed gas, an operation of the polishing material supply apparatus 2 including a delivery apparatus 13, and an apparatus main body. A control unit 17 for controlling the operation of the pump device 5 in the unit 1 and the opening / closing of the on-off valves 10-1, 10-2, 10-3 provided in the liquid supply paths 6-1, 6-2, 6-3, respectively. It is configured so that opening / closing and operation of each component can be controlled by a signal from the control unit 17. The pressure of the compressed gas and the pressure of the high-pressure water are also configured to be appropriately set and adjusted in the control unit 17.

  A case will be described in which blasting treatment such as rust prevention, roughening, and washing is performed on a structural material such as a steel ship using the above-described mixed-air jet blasting apparatus A.

  Usually, the main power source (not shown) provided in the apparatus main body 1 is turned on, the pump device 5 of the liquid supply path 6 is operated, and 8 to 75 MPa is supplied through the liquid supply paths 6-1, 6-2, and 6-3. High-pressure water is fed to any one of the nozzles 7-1, 7-2 and 7-3, for example, the mixed gas jet nozzle 7-2. A compressed gas of 7 MPa is fed into the mixed jet nozzle 7-2.

  Here, the compressed gas supplied by the gas supply path 3 is controlled by the delivery device 13 in the supply device 2 of the abrasive material connected to a part of the gas supply path 3 during the supply. A predetermined amount of the abrasive specified by 17 is mixed and pumped. In particular, when the baking soda dilution water is not used for the high-pressure water, the polishing material mixed with baking soda powder is mixed and pumped.

  That is, the supply tank 12 of the supply device 2 has a particle size of 500 microns or less for a polishing material composed of metal particles having a particle size of 100 to 2000 microns or inorganic particles other than metal, such as copper slag, in a separate process. In addition, a polishing material obtained by adding and mixing 2 to 10% by weight of a baking soda powder of preferably 100 microns or less is temporarily stored, and this polishing material, that is, a state in which baking soda is attached to the surface in the form of a coating film The abrasive is fed into the gas supply path 3 by the delivery device 13, mixed into the compressed gas flowing in the gas supply path 3, and pumped to the air-jet nozzle 7-2 as the abrasive mixture gas. At the same time, by the operation of the pump device 5 in the liquid supply path 6, high-pressure water, for example, high-pressure water of 10 to 100 MPa, is fed from the liquid tank 4 to the mixed gas jet nozzle 7-2.

  In the mixed-air jet nozzle 7-2, the compressed gas containing the abrasive and the high-pressure water are mixed, and as shown in FIG. 2, from the nozzle tip 7-2a, a jet-like mixed jet stream 22 is processed. Blasting is performed toward the surface of B to perform blasting treatment such as peeling of deposits and removing rust. In this blast treatment, the mixed jet stream 22 of compressed gas and high-pressure water contains a fine-grained abrasive K, and the abrasive K collides with the mixed jet 22 on the surface of the workpiece, Rust removal and rust prevention work such as removal of deposits and removal of rust on the surface of the treated object can be performed effectively, and the surface of the treated object is roughened by forming fine irregularities by using the polishing material K. Work can be done at the same time. Moreover, since high pressure water is used, generation | occurrence | production of dust like the conventional sandblasting process and deterioration of a working environment can be suppressed.

  Moreover, since the baking soda powder adheres to the surface of the fine-grained polishing material K injected together with the mixed jet stream 22 or the baking soda powder is mixed with the polishing material mixture gas, the polishing material By forming a baking soda film on the surface of the object B to be processed by K, the surface of the object to be processed is covered and protected by an alkaline film, and the occurrence of return rust can be suppressed. That is, the occurrence of return rust can be suppressed despite the use of high-pressure water. Even after a predetermined time has elapsed, the occurrence of return rust on the surface of the workpiece can be suppressed. The surface of the object to be treated is preferably applied after the surface is completely dried by leaving it for a predetermined time.

  In the blasting process, when cleaning work such as removal of dirt or cleaning of the surface of the workpiece is performed, the opening / closing valve 10-2 of the gas supply path 3 is closed and the operation of the polishing material supply device 2 is stopped. In order to operate only the pump device 5, one of the on-off valves 10-1 and 10-3 of the liquid supply passages 6-1 and 6-3 is opened, and the fume washing nozzle 7-1 or the water washing nozzle 7-3 is opened. By supplying high-pressure water to one of them and spraying it onto the surface of the object to be processed from the nozzle tip 7-1a or 7-3a, it is possible to perform cleaning operations such as dirt removal and washing.

  In particular, the liquid supply path 6 to which the fume cleaning nozzle 7-1a or the water washing nozzle 7-3a is connected separately from the liquid supply path 6-2 and the connection portion 8-2 to which the mixed air jet nozzle 7-2 is connected. -1, 6-3 and connecting parts 8-1, 8-3 are provided so that the nozzle to be used can be switched, thereby removing rust, preventing rust and roughing, and cleaning such as removing dirt. Operations can be performed in a unified manner using a single device, and each operation can be performed efficiently.

  In the present invention, as in the above-described embodiment, the abrasive supply device 2 provided in the gas supply path 3 is fed with the abrasive material added with sodium bicarbonate to the gas supply path 3 to supply the gas. It is fed to the air-jet jet nozzle 7-2 of the spray nozzle part as a polishing material mixture gas containing sodium bicarbonate through the path 3 and sprayed in a state in which sodium bicarbonate is mixed into the mixed jet stream, and is also fed to the spray nozzle part As the high-pressure water to be used, diluting water mixed with baking soda on the liquid supply source side such as the liquid tank 4 in advance, preferably diluting water mixed in a ratio of 2 to 10% by weight, is mixed with the mixed jet stream. It can be injected in the state.

  In this case, a predetermined amount of baking soda is mixed in a part of the liquid tank 4 and other water supply channels on the liquid supply source side of the high-pressure water and used as diluting water for baking soda. Therefore, in the abrasive material supply device 2, the abrasive material can be used as it is without adding sodium bicarbonate.

  In the case of this example as well as the above example, it is possible to effectively perform rust removal and rust prevention work such as peeling and rust removal of deposits on the surface of the object to be processed, and simultaneously performing roughing work, Moreover, deterioration of the working environment can be suppressed. Moreover, the surface of the object to be treated is covered and protected by a coating of alkaline baking soda, and the occurrence of return rust can be suppressed. In particular, since the mixed state of baking soda in the mixed jet stream can be equalized, the baking soda film formed on the blasted surface can also be equalized, so that the occurrence of return rust can be satisfactorily suppressed.

(Examples 1-4 and Comparative Example 1)
In order to confirm the above effect, in the mixed-air jet blasting method in which high-pressure water, compressed gas, and abrasive are carried out under the following conditions, sodium bicarbonate having a particle size of 500 μm or less is added to and mixed with the abrasive having a particle size of 2000 μm or less. This is mixed with the compressed gas, supplied to the injection nozzle, and injected together with the mixed injection flow of the abrasive mixture gas and high-pressure water, and the steel sheet surface of the test piece is blasted by the mixed injection flow of this baking soda mixture The method to carry out was carried out under the conditions shown in Table 1 below, changing the mixing ratio of baking soda to the abrasive (Examples 1 to 4). In addition, the case where sodium bicarbonate was not mixed (Comparative Example 1) was carried out. After each blasting treatment, drying (2 hours), removal of precipitate residue with water and air blow drying were performed, and the occurrence of return rust on the surface was observed. The results are shown in Table 1 below.

High pressure water: High pressure water of 75 MPa Compressed gas: Compressed air of 0.7 MPa Abrasive material: Copper slag with an average particle size of 1000 μm

(Examples 5 to 8)
In the same mixed-air jet blasting method as described above, the baking soda dilution water mixed with baking soda was used as the high-pressure water. After the blasting treatment, drying (4 hours), washing and removing the deposit residue was performed, and air blow drying was performed, and the occurrence of return rust on the surface was observed. The results are shown in [Table 2] below.

  As described above, when sodium bicarbonate was not mixed (Comparative Example 1), return rust was observed, but when sodium bicarbonate was mixed with the abrasive as in the present invention, sodium bicarbonate was added to the high pressure water. When diluting water was used, no or little return rust was observed.

  A ... mixed gas jet blasting device, B ... workpiece, K ... scouring material, 1 ... device main body, 2 ... scouring material supply device, 3 ... gas supply path, 4 ... liquid tank, 5 ... pump device 6-1, 6-2, 6-3, liquid supply path, 7-1, fume washing nozzle, 7-2, mixed-air jet nozzle, 7-3, water washing nozzle, 7-1a, 7-2a, 7 3a ... Nozzle tip, 8-1, 8-2, 8-3 ... Connection part, 9 ... Distributor, 10-1, 10-2, 10-3 ... Open / close valve, 11-2, 11-3 ... Regulator DESCRIPTION OF SYMBOLS 12 ... Supply tank, 13 ... Cleaning device delivery apparatus, 14 ... Opening and closing valve, 15 ... Filter, 16 ... Air filter, 17 ... Control part, 18 ... Opening / closing valve, 19 ... Connection part, 22 ... Mixed injection flow.

Claims (8)

A gas supply path having a gas supply path for supplying compressed gas from a compressed gas supply source to the injection nozzle section and a liquid supply path for supplying high-pressure water from the liquid supply source to the injection nozzle section via a high-pressure pump. A method of blasting the surface of an object to be processed by mixing compressed gas supplied by a path and high-pressure water supplied by a liquid supply path at an injection nozzle portion and injecting the nozzle toward the object to be processed. In
Leave connect supply apparatus abrasive cleaning agent for performing roughening eye of the object to a part of the gas supply passage, the Institute cleaning agent consisting of inorganic particles other than the metal particles or metal, a predetermined amount by It is mixed with compressed gas and pumped, and sprayed together with the mixed jet flow of the compressed gas and high-pressure water from the spray nozzle part. At this time, sodium bicarbonate for returning to the mixed spray flow and preventing rust is mixed. A mixed-air jet blasting method for steel materials characterized by jetting.   A state in which baking soda having a particle size of 500 microns or less is added and mixed in a ratio of 2 to 10% by weight to the polishing material mixed in the compressed gas from the abrasive supply device, and sodium bicarbonate is mixed in the mixed jet stream. The mixed-air jet blasting method according to claim 1, wherein the air-jet jet blasting method is performed.   Diluted water in which sodium bicarbonate is previously mixed at a ratio of 2 to 10% by weight is used as the high-pressure water to be fed to the spray nozzle portion, and sprayed in a state where sodium bicarbonate is mixed in the mixed jet stream. Item 4. The mixed air jet blasting method according to item 1.   The mixed jet blasting method according to claim 2 or 3, wherein the particle size of the abrasive is 100 to 2000 microns.   The polishing material capable of forming minute irregularities on the surface of the workpiece is sprayed from the spray nozzle portion at an ejection speed capable of forming minute irregularities on the surface of the workpiece. The mixed-air jet blasting method according to any one of the above. A gas supply path for supplying compressed gas from a compressed gas supply source to the injection nozzle section, a liquid supply path for supplying high-pressure water from the liquid supply source to the injection nozzle section via a pump device, and a gas supply path. A mixed-air jet blasting device having an injection nozzle unit that mixes compressed gas to be fed and high-pressure water fed by a liquid supply path, and injects the compressed gas and high-pressure water mixed toward a workpiece. There,
The gas supply path connected to a part of, Ri Do inorganic particles other than the metal particles or metal object to be processed in the roughening is carried out abrasive cleaning agent a predetermined amount by the supply device of abrasive cleaning agent mixed in the compressed gas With
The gas supply path or the liquid supply path is provided as a supply path for supplying sodium bicarbonate for preventing return rust to the spray nozzle part,
The injection nozzle unit, admission jet for steel, characterized in that said Labs cleaning agent is configured to be injected while mixing the sodium bicarbonate to a mixed jet of the compressed gas and high-pressure water mixed Blasting device. Opening and closing of an opening / closing valve provided in the gas supply path for supplying / stopping compressed gas, operation of the supply device of the abrasive material, operation of the pump device, and opening / closing of the opening / closing valve provided in the liquid supply path, respectively. The mixed-air jet blasting device according to claim 6, further comprising a control unit for controlling. The supply device of the polishing material supplies a polishing material capable of forming minute unevenness on the surface of the object to be processed, and the spray nozzle portion forms minute unevenness on the surface of the object to be processed. The mixed-air jet blasting apparatus according to claim 6 or 7, wherein the air-jet jet blasting apparatus performs injection at an injection speed capable of performing

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