JP2016155208A - Inert gas circulation type blasting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inert gas circulation type blasting device where a shredded work can be effectively reutilized and measures against dust explosion can be easily and safely achieved even when the fine particles of a metal or an alloy are used as a shot material for the work.SOLUTION: In an inert gas circulation type blasting device comprising a cabinet housing a work, a projection portion projecting a shot material, a blower making a gas flow energizing the shot material and a dust collector collecting dust in a gas by suctioning the gas in the cabinet, an inert gas is filled in the cabinet and the inert gas is circulated in the blower, the cabinet and the dust collector.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blasting apparatus that projects a shot material onto a processed product (work) and performs processing such as surface grinding. In particular, the crushed material of the processed product can be effectively reused, and dust explosion countermeasures are taken easily and safely. The present invention relates to an inert gas circulating blasting apparatus.

  Conventionally, blasting has been known as a surface processing method in which a particle called a shot material is projected and collided with a processed product (workpiece) to process the workpiece. And this blasting process is widely used industrially for the purpose of mainly removing burrs on the workpiece, surface grinding, and satin finishing.

  For the shot material, metal particles such as aluminum and zinc, ceramic particles such as alumina and silicon carbide, or resin particles such as nylon and polycarbonate are appropriately selected according to the purpose of use and processing purpose. It is used.

  However, when blasting is performed conventionally, the projected particles and the particles generated from the processed products fly up into the air as dust, and in a floating state, dust explosion occurs due to static electricity and other factors. There was a danger to do. There are combustible materials (dust here), oxygen, and ignition sources as the conditions for the dust explosion, which are generated when they come into contact under various conditions. In particular, when a metal material such as aluminum or magnesium is used for shot materials and / or workpieces, the metal material has the property of easily generating static electricity that is a source of ignition, so there is a high risk of causing a dust explosion. It was.

  In order to avoid such a dust explosion, various techniques for taking an explosion-proof measure by changing the shot material or injecting a mixed solution of water and the shot material have been proposed.

  For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 10-249733) provides a shot with high safety without damaging the appearance of the surface of the object to be ground as a grinding material for a metal product having a white appearance such as aluminum die casting. Proposing technology. That is. It proposes a granular tin shot obtained by spraying air into the hot water and dropping it into liquid oil while dropping the molten hot tin heated to the melting point or higher and a method for producing the same.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2013-15884) proposes a substrate polishing apparatus that can prevent abrasive grains and the like from entering a region where polishing is not performed and can keep the inside of the apparatus clean. ing. That is, by supplying the protective liquid to a part or all of the part where the substrate-like treatment is not performed, and the spraying means for spraying the liquid for mixing the abrasive grains and the liquid into a mist with a compressed gas and spraying it onto the substrate. Substrate protection means for forming a liquid layer and protecting the substrate from the mist-like mixing liquid, suction recovery means for sucking the mixed liquid and the protective liquid after jetting, and the mist by the jetting means And a first control means for controlling a suction amount of the mixing liquid and the like by the suction recovery means. A device is proposed.

JP 10-249733 A JP 2013-15884 A

  As described above, various techniques for taking countermeasures against explosion by changing the shot material or injecting a mixed solution of water and shot material have been proposed. However, in Patent Document 1, there is a problem that only a specified shot material (tin in Patent Document 1) can be used as an explosion-proof measure. That is, in performing the blasting process, various shot materials may be used depending on the processing purpose and the workpiece material. Therefore, when the material of the shot material is limited, the material of the work that can be processed and the shape of the work after the blasting process are limited, and it is difficult to perform the processing as desired.

  Further, in performing wet blasting as shown in Patent Document 2, when a metal workpiece is used, the workpiece becomes wet and rusts, and the post-treatment of water is troublesome. there were.

  Therefore, in the present invention, it is a first object to provide an inert gas circulation blasting apparatus that can easily and safely take measures against dust explosion without limiting the shot material and workpiece material that can be used.

  In recent years, attention has been focused on 3D additive manufacturing technology using metal powder and the like, and various organizations are focusing on research and development, technological development and practical application. The 3D additive manufacturing technology using such metal powders is a technique for producing a three-dimensional object by irradiating energy such as a laser beam or an electron beam and laminating layers obtained by selectively melting and solidifying metal powders. In particular, various metal powders can be used in 3D additive manufacturing technology using an electron beam as an energy source.

  However, in the 3D additive manufacturing technology using an electron beam, when the metal powder is preheated or melted / solidified, the calcination exists around the three-dimensional structure in a state where the metal powder is not melted or sintered. Conjugation occurs. Therefore, a technique for crushing the temporary sintered body is required. In addition to the 3D additive manufacturing technique using an electron beam, blasting may be performed on a modeled object made of metal powder in order to improve the surface state of the modeled object. In order to effectively disintegrate only the pre-sintered body, to improve the modeling accuracy of the metal powder molding, or to improve the surface condition, a metal or alloy having a fine particle size as possible as a shot material It was desirable to use However, when a material such as a metal or alloy having a fine particle size is used as a shot material, there is a risk that the risk of generating a dust explosion is increased.

  Therefore, the present invention provides an inert gas circulation blasting device that can prevent dust explosion even if a metal or alloy having a fine particle diameter is used as a shot material. Let it be the second issue.

  Furthermore, as described above, when the metal powder is melted and solidified using an electron beam, a pre-sintered body that is neither molten nor sintered is formed around the shaped object due to preheating or melting. Therefore, the temporary sintered body is crushed and removed by blasting, but it is desirable to effectively use the crushed temporary sintered body in order to eliminate waste of materials. This is particularly noticeable when the metal material is expensive. Further, when such a temporary sintered body is crushed, a large amount of metal powder is generated and floats up and floats, so that the risk of dust explosion is expected to increase.

  Therefore, in the present invention, it is a third object to provide an inert gas circulation blasting device that is devised so that the pulverized material of the processed product in the blasting process can be effectively reused while keeping the risk of dust explosion low. And

  In order to solve at least one of the above problems, in the present invention, a pulverized product can be effectively reused, and a dust explosion countermeasure can be taken easily and safely by reducing the oxygen concentration in the internal space of the blasting device. An inert gas circulation type blasting apparatus capable of achieving the above is provided.

  That is, the present invention provides a cabinet for storing a processed product, a projection unit for projecting shot material to the workpiece stored in the cabinet by an air current, a blower for generating an air current for energizing the shot material, and a cabinet It is a blasting device comprising a dust collector that sucks in the gas and collects dust in the gas, and the cabinet is filled with an inert gas, the inert gas is the blower, The present invention provides an inert gas circulating blasting device characterized by circulating a cabinet and a dust collecting device.

  The processed product widely includes structures formed of hard materials such as metal, ceramic, glass, and plastic, and structures formed of soft materials such as rubber, and is large in material, size, shape, weight, etc. There is no limit. However, in view of the purpose of installing in the apparatus and performing blasting, it is desirable that the shape be easy to carry and / or install and use a weight that does not cause damage to the apparatus. Is desirable. In particular, the blasting apparatus according to the present invention is more prominent when the processed product is a structure made of a metal or an alloy that is a material that easily generates an ignition source (such as static electricity) that may cause a dust explosion. There is an effect. Further, it is effective when a large amount of metal powder is generated, and is useful for the purpose of crushing a temporary sintered body of a three-dimensional structure formed by an electron beam. Therefore, the processed product processed by the blasting apparatus according to the present invention can exhibit the maximum effect when it is a three-dimensional structure formed by an electron beam.

  As the shot material, a shot material made of various materials such as metal, ceramic, or resin can be used as appropriate. However, in consideration of the action and effect for avoiding the risk of powder explosion in the present invention. For example, it is particularly effective when a shot material made of a metal or alloy material such as aluminum, zinc, alloy, flint, grid, cast steel or the like is used. Furthermore, it is desirable to use the same shot material as the processed product. When the blasting apparatus according to the present invention is used for the purpose of pulverizing a temporary sintered body of a three-dimensional structure formed by melting and solidifying metal powder with an electron beam, the pulverized material can be reused. Because. Such a pulverized product can be used as a shot material in addition to being used as a modeling material (metal powder) for forming a three-dimensional modeled object again.

  Therefore, it is desirable for the blasting apparatus according to the present invention to reuse at least part of the pulverized product as a shot material or a modeling material for the processed product. It is desirable to save expensive material costs and the like.

  The cabinet functions as a space for housing the processed product and performing blasting. There are no restrictions on the material and size of the cabinet, but it is desirable to use a stainless steel material in view of rust prevention, and if the crushed material is used as a shot material or modeling material, the contamination should be reduced. In order to prevent this, it is desirable that the inner wall surface be formed of a material harder than the shot material (and modeling material) or the same material as the shot material (and modeling material). Further, it is desirable that the interior (inner wall) of the cabinet has a smooth planar structure with as few steps and irregularities as possible in order to prevent deposition and adhesion of shot materials or crushed materials. Further, it is desirable to provide a gradient so that the lower part of the cabinet is recessed downward so that the crushed product can be dropped downward and collected in one place. In addition, during blasting work, an opening is provided on the side of the cabinet, a lighting device is installed, a maintenance door for entering and exiting processed products, and device control so that the user can insert a hand into the cabinet. A control box or the like in which the electrical equipments are arranged may be appropriately arranged according to the purpose of use.

  However, when an opening or the like is provided on the side surface of the cabinet, it is desirable to have a sealed structure so that the gas in the cabinet does not leak to the outside so that the gas circulation is not hindered. In addition, an explosion pressure diffusion port is provided at the top and sides of the cabinet (however, on the side other than the side on which the operator works) in order to protect the operator by spreading the pressure in case a dust explosion occurs. It is good to provide. Furthermore, it is desirable to provide a pulverized material sorting means such as a sieve mesh on the lower side in the cabinet. This prevents large crushed material from entering the media storage tank, which will be described later, and reuses the collected large crushed material as shot material or modeling material for processed products. This is to remove the crushed material. The pulverized material separation means may be provided with a pulverizing means for finely pulverizing the removed large crushed material. As such pulverizing means, known pulverizing means such as a ball mill and a high-pressure pulverizing roll can be used.

  Here, the said cabinet is connected with the dust collector which attracts | sucks the gas in a cabinet and collects the dust in the said gas. As such a dust collector, one suitable for collecting dust can be used. For example, a device composed of a cyclone and a dust collector that collects dust by centrifugation is common, but a cloth bag type dust collector, a wet dust collector, or the like may be used according to the application. However, when using ultra-fine shot material, etc., it may not be possible to achieve complete dust collection even if the dust collector is used alone. You may install it.

  Moreover, the gas from which the dust has been removed by the dust collector is transferred to the blower. This blower is a device for generating an air flow that urges the shot material, and a blower fan, a compressor, or a roots-type rotary blower can be used. However, a roots type rotary blower is desirable. Unlike a system using a fan, this is a structure in which the intake side and the discharge side of the air are always completely partitioned, so that the high-pressure air on the discharge side does not leak to the intake side even when stopped. Because it is good. Further, the rotation control of the rotary blower makes it easy to adjust the air flow rate, and since no lubricating oil is used, no oil component is mixed into the blown air. Furthermore, since intake and exhaust are performed at the same time, an air supply device suitable for a blast device can be configured, such as being able to cope with a large air volume. An air flow is generated by the blower, the shot material is energized by the energized air current, the shot material is projected from the projection unit formed using a spray gun or the like, and the workpiece is blasted.

  Here, in the blasting apparatus according to the present invention, the inside of the cabinet and the piping system are all sealed, an inert gas such as nitrogen or argon is introduced and filled in the apparatus, and the inert gas is circulated using the blower. Let That is, by replacing the gas in the apparatus with an inert gas, the internal oxygen concentration is made lower than the dust explosion limit value, and the generation factor of the dust explosion can be prevented beforehand. Specifically, it is desirable to set the oxygen concentration in the apparatus to less than 5% (particularly less than 3%). When a certain oxygen concentration is detected, the inert gas is introduced again, and the inert gas is introduced. Desirably, the replacement is performed. The inert gas replacement operation can also be performed by automatic control, and may have a structure in consideration of safety, for example, by providing an interlock function in which the blast operation does not function unless the specified oxygen concentration is reached.

  According to the above configuration, the oxygen concentration inside the apparatus can be always maintained at an oxygen concentration lower than the dust explosion limit value, so that the processed product and / or the shot material is a material such as a metal or alloy having a fine particle diameter. Even when using, dust explosion countermeasures can be taken effectively and safely. Depending on the application, dry ice may be used as a shot material. Even when dry ice is used as a shot material, in the present invention, by supplying an inert gas, the internal humidity can be suppressed lower than that of a single dry ice shot, so that a more effective processed product. Can be cleaned. That is, since there are no restrictions on the material and particle size that can be used for shot materials and processed products, it is possible to use a blasting device in a wider range (wide field). Furthermore, the possibility of generating ignition sources such as static electricity can be greatly reduced.

  Moreover, it is desirable to provide a media storage tank below the cabinet for storing the pulverized product accumulated in the cabinet. The material and shape forming the media storage tank can be set as appropriate according to the application, but the capacity is set so that a large amount of the pulverized product can be stored in consideration of long-term blasting. Is desirable. Especially when it is used for the purpose of pulverizing a temporary sintered body of a three-dimensional structure formed by melting and solidifying a metal powder with an electron beam, and when using the crushed object as a modeling material or a shot material Since the crushed material and the shot material are stored, it is desirable to secure a large capacity.

  Furthermore, it is desirable to provide a rotary valve on at least one of the outlet side of the pulverized product produced in the cabinet and the inlet side of the crushed material in the media storage tank. This is because by providing a rotary valve, it is possible to adjust and control the flow rate of the crushed material by a rotating action, so that a large amount of the crushed material can be prevented from falling, and the eyes on the inlet side of the media storage tank can be prevented. This is because the risk of clogging and the like can be greatly reduced. Moreover, by using a rotary valve, a crushed material can be sent out irrespective of the atmospheric | air pressure of the space which exists on the both sides of the said rotary valve.

  Moreover, you may provide the classification part which can classify at least any one of a magnitude | size, a shape, and a weight of the pulverized material of a processed product. The said classification part should just be used in order to classify a granular material conventionally, and can be suitably used according to a use, such as a sieve, a centrifugal cyclone, or a liquid cyclone. For example, when it is desired to classify the crushed material into a plurality of media storage tanks, a plurality of the media storage tanks are used, and the plurality of media storage tanks are arranged in parallel or in series, and a classification unit for sorting the media storage tanks is provided. Thus, it can be classified as a shot material, a modeling material for a processed product, or other materials according to the particle size and the like, and each can be reused.

  Further, in addition to the classifying portion, it is desirable to provide a pulverizing means for further finely pulverizing the pulverized material of the processed product in order to form a shot material or a granule that can be used for other purposes. Providing such pulverizing means separately enables reuse of more crushed materials, leading to saving of materials.

  Here, a mixer is provided below or on the side of the media storage tank for introducing the crushed product of the processed product generated in the cabinet into the gas discharged from the blower. By providing the mixer, the pulverized material of the processed product finely crushed by the classification unit or the pulverizing means is mixed into the gas sent out from the blower and can be projected as a shot material. That is, since a crushed product of a processed product can be reused as a shot material without newly adding a shot material, permanent blasting is possible. In particular, if a shot material made of the same material as the processed product is used, the powder present in the cabinet can be used as a shot material simply by classification.

  The gas discharged from the blower is provided so as to branch into a first system that passes through the mixer to reach the projection unit and a second system that is supplied into the cabinet without passing through the mixer. In particular, it is desirable that the gas suction port directed to the dust collector in the cabinet should be provided closer to the processed product accommodated in the cabinet than the supply port to the second system cabinet. This is because the gas pressure in the cabinet is adjusted by branching the gas discharged from the blower to efficiently circulate the gas. In addition, by making the gas suction port toward the dust collector in the cabinet closer to the processed product than the supply port of the second system, the amount of gas suction toward the dust collector is projected near the processed product. The amount of gas discharged from the section can be increased. Thereby, the dust absorption effect in a cabinet can be heightened.

  If the said structure is followed, since the classified crushed material can be reused as a shot material through a mixer, blasting is possible without the need to replenish the shot material. That is, even when an expensive metal or alloy material is used for a shot material and / or a processed product, the need to newly insert a member is reduced as much as possible, which leads to saving of the member and labor cost. Moreover, since the classified relatively large pulverized product can be reused as a modeling material for a processed product, it can also lead to saving of raw material costs of the processed product.

  According to the above invention, the inside of the apparatus is filled with an inert gas, and the inert gas is circulated using a blower, so that the internal oxygen concentration is lower than the dust explosion limit value, and the dust explosion Occurrence can be prevented.

  In addition, since dust explosion countermeasures are taken, the risk of dust explosion can be greatly reduced even if a metal or alloy with a fine particle diameter is used as a material for shot materials and processed products. That is, the blasting process can be performed effectively without limiting the shot material and the workpiece material.

  Furthermore, the crushed product of the processed product crushed by the shot material that has been projected can be effectively reused as at least a part of the shot material or the modeling material of the processed product, leading to saving of material.

  Furthermore, since the classified crushed material can be reused as a shot material through a mixer, continuous blasting is possible, and the need to add new members is reduced to a minimum. It also leads to labor cost savings.

  In particular, when crushing a temporary sintered body of a three-dimensional structure (processed product) formed by melting and solidifying a metal powder with an electron beam, the crushed object can be reused as a shot material or a modeling material. Since expensive metal materials can be saved, great cost merit can be found.

It is a block diagram which shows the whole structure of the inert gas circulation blasting apparatus concerning 1st Embodiment. It is a longitudinal cross-sectional schematic diagram which shows the internal structure of the air blower (roots type rotary blower) concerning 1st Embodiment. It is a block diagram which shows the whole structure of the inert gas circulation blasting apparatus concerning 2nd Embodiment. It is a block diagram which shows the whole structure of the inert gas circulation blasting apparatus concerning 3rd Embodiment. It is a block diagram which shows the whole structure of the inert gas circulation blasting apparatus concerning 4th Embodiment. It is a longitudinal section schematic diagram showing a separation part (louver type dust separation device) concerning other embodiments.

  Hereinafter, the inert gas circulation blasting apparatus according to the present embodiment will be described in detail with reference to the drawings. However, the inert gas circulation blasting apparatus according to the present invention is not limited to the present embodiment, and can be appropriately changed without departing from the gist of the invention.

  FIG. 1 is a block diagram showing the overall configuration of the inert gas circulation blasting apparatus according to the first embodiment. This inert gas circulation blasting apparatus B is a cabinet that divides a space for storing a processed product 11. 12, a projecting unit 13 that projects the shot material 14 onto the processed product 11 accommodated in the cabinet 12, a blower 26 that generates an airflow that urges the shot material 14, and a gas in the cabinet 12 It consists of a dust collector 17 (cyclone 15 + dust collector 16) that collects dust, and each is connected by a pipe 18.

  The cabinet 12 has a large window 32 formed in the front so that the blasting state can be visually confirmed, and an opening 30 is provided below the window 32 so that a hand can be inserted during the blasting operation. Yes. A glove made of a flexible material such as rubber or silicon is attached to the opening to prevent gas from flowing through the opening. In addition, the lower part of the cabinet 12 is formed with a slope so as to be narrowed downward so that the crushed product of the processed product 11 can be easily dropped downward. (Large) 25A is selected. Further, a media storage tank 22A having a classification unit 23 for storing crushed materials is provided below the cabinet 12, and a media storage tank 22B for storing finer crushed materials is further provided below the cabinet 12.

  That is, from the crushed material of the processed product 11 accumulated in the cabinet 12, first, the large crushed material (large) 25A is removed by the sieve mesh 34, and the other crushed material is dropped downward. Then, the pulverized product is classified into finer ones by the classifying unit 23, and the classified relatively large crushed product (medium) 25B is accommodated in the media accommodation tank 22A. The fine crushed material (small) 25C classified by the classifying unit 23 is accommodated in the medium accommodating tank 22B and is configured to be reusable as the shot material 14. The crushed material (large) 25 </ b> A and the crushed material (medium) 25 </ b> B can be collected and reused as a modeling material for the processed product 11. That is, in the present embodiment, the same material is used as the molding material for the shot material 14 and the processed product 11 in order to reuse the crushed material.

  With the above configuration, the large crushed material (large) 25A is sieved by the sieve mesh 34 in the cabinet and does not enter the media storage tank 22A. The crushed material that has passed through the sieve screen 34 is classified by the classifying unit 23 and is divided and accommodated in the media accommodation tank 22A and the media accommodation tank 22B. The sieve screen 34 can be installed not in the cabinet but in the media storage tank 22A, and the crushed material can be classified in the media storage tank 22A. In the present embodiment, the media storage tank 22A and the media storage tank 22B are arranged in series, but can also be installed in parallel. In this case, the classified crushed material is supplied to each media storage tank. (22A or 22B) can be stored separately.

  Further, in addition to the classifying unit 23, a separate crushing means may be provided so that the crushed material (large) 25A and the crushed material (medium) 25B can be further finely crushed and reused as the shot material 14. . Further, a rotary valve 24 may be provided on the outlet side of the cabinet 12 and / or the inlet side of the crushed material in the media storage tank 22B to control the flow rate of the crushed material. By providing the rotary valve, the crushed material can be transferred even if the air pressure in the spaces existing on both sides thereof is different.

  Further, a mixer 27 is provided below the medium storage tank 22B that stores fine crushed materials (small). The mixer 27 is a member that throws the fine crushed material (small) into the gas discharged from the blower 26. That is, the pulverized product (small) 25C finely crushed by the above configuration can be mixed with the gas discharged from the blower 27 and projected as the shot material 14 by the fluid energy of the gas.

  In other words, according to the above configuration, the classified crushed material (small) 25C can be reused as the shot material 14 through the mixer 27, and thus blasting can be performed permanently. As a result, even when an expensive metal or alloy material is used for the shot material 14 and / or the processed product 11, the need to newly add the shot material 14 is reduced as much as possible. Can be connected.

  Here, the gas flow direction 21 and the flow path in the blasting apparatus according to the present embodiment will be described. First, the gas including the shot material 14 projected from the projection unit 13 existing in the cabinet 12 is in the upper part of the cabinet 12. It is led to the cyclone 15 through a suction port 35 provided with a filter 36. Then, the shot material 14 is separated from the gas by the centrifugal action of the cyclone 15, and the gas from which the shot material 14 is removed is guided to the dust collector 16 using the intake air of the blower 26, and the blast dust contained in the gas Is filtered and transferred to the blower 26.

  Here, as shown in FIG. 2, in this embodiment, a roots type rotary blower is used for the blower 26. This Roots type rotary blower accommodates two rotors 37 having the same shape of two leaves (or three leaves) in a casing 38 and rotates the rotor 37 at the same speed in opposite directions by using the power of a motor or the like. By being driven, the gas sucked from the intake port 39 is pressurized in a space surrounded by the casing 38 and the rotor 37 and discharged from the exhaust port 40. If a roots-type rotary blower is used for the blower 26, it becomes easy to adjust the amount of blown air by rotational control, and since no lubricating oil is used, oil is not mixed in the blown air, and intake and exhaust are made simultaneously. An air supply device suitable for a blasting device, such as being capable of handling a large amount of air, can be configured.

  And the gas discharged | emitted from the air blower 26 is gas from the supply port formed in the lower part of the cabinet 12 without passing through the mixer 27, and the 1st system | strain 28 which reaches the projection part 13 through the mixer 27. Branching to the second system 29 to be supplied. In addition, the gas suction port 35 toward the dust collector 17 in the cabinet 12 exists closer to the processed product 11 accommodated in the cabinet 12 than the supply port 33 into the cabinet 12 of the second system 29. It is provided as follows. This is because the gas pressure in the cabinet is adjusted by branching the gas discharged from the blower 26 to efficiently circulate the gas. In the present embodiment, the opening of the second system 29 exists in a region where the crushed material is stored in the cabinet, but the opening of the second system 29 is a processed product rather than the gas suction port 35. Since it is sufficient if the distance is long, it can be provided at an arbitrary place. However, it is desirable that the position should not blow up the crushed material deposited in the lower part of the cabinet.

  In addition, it is also possible to pipe the crushed material stored in the media storage tank 22A to the material tank or the like existing at a remote location by using the branched gas flow of the second system 29. . In such a configuration, it is desirable to provide a separation device that collects the crushed material from the gas also in the material tank of the transfer destination, and the gas from which the crushed material has been removed can be returned to the upstream side of the blower 26 such as in the cabinet again. .

  Further, in the blasting apparatus according to the present embodiment, the cabinet 12 and the piping 18 system are all sealed, and an inert gas such as nitrogen or argon is introduced and filled in the apparatus, and the blower 26 is used. The inert gas is circulated. In the present embodiment, an inert gas is supplied into the apparatus using an inert gas cylinder 19 via a pipe 18 extending from the dust collector 17 to the blower 26.

  That is, by replacing the gas in the apparatus with an inert gas, the internal oxygen concentration is made lower than the dust explosion limit value, thereby preventing the occurrence of dust explosion. Specifically, the inert gas is introduced until the oxygen concentration in the apparatus reaches less than 3%. It is desirable to detect the oxygen concentration with the oxygen concentration meter 31 at the upper part of the cabinet (particularly preferably, the oxygen concentration meter 31 is preferably installed at several locations). Then, when the oxygen concentration reaches 3% or less, the introduction of the inert gas is stopped, and the blower 26 is started to circulate the inert gas in the apparatus. When the oxygen concentration is detected to exceed 4% within the set time (working time), the inert gas is introduced again and the inert gas replacement is performed. The inert gas replacement operation is performed by automatic control. An alarm may be issued when the oxygen concentration is in the 5% range, and an interlock function may be provided in which the blast operation does not function when the oxygen concentration is 6% or more. In addition, when the supply pressure from the inert gas cylinder is lowered, it is preferable to provide a function of issuing an alarm and stopping the apparatus.

  With the above configuration, the oxygen concentration inside the apparatus can always be maintained at an oxygen concentration lower than the dust explosion limit value, so that the processed product 11 and / or the shot material 14 can be made of a metal or alloy having a fine particle diameter. Even when materials are used, it is possible to effectively and safely take measures against dust explosions.

  3 to 5 show a blasting apparatus according to another embodiment. That is, the basic configuration of the inert gas circulation blasting apparatus B2 shown in FIG. 3 is the same as that of the first embodiment, but the media tank storage tank 22A that stores the crushed crushed material (medium) 25B is used. Piping is provided in the side part, and it connects with the 3D additive manufacturing technology apparatus 41 installed separately. That is, means for conveying the disassembled crushed material (medium) 25 </ b> B to the 3D additive manufacturing technology apparatus 41 using the circulation energy of the gas output from the blower 26 is used. Although not shown in the drawing, the 3D additive manufacturing technology apparatus 41 separates the gas and the crushed material using a cyclone type powder separation device or the like that separates and extracts only the crushed material from the conveyed gas. The crushed material can be used as a processing material in the 3D additive manufacturing technology apparatus 41, and the gas can be returned to the blasting apparatus.

  After the crushed material (medium) 25 </ b> B is conveyed to the 3D additive manufacturing technology apparatus 41, the gas from which the crushed material is separated and taken out is returned to the pipe between the cyclone 15 and the dust collector 16. Therefore, according to the above configuration, there is no need to manually collect the crushed material (medium) 25B crushed by blasting, and it can be conveyed to the 3D additive manufacturing technology apparatus 41 using the gas output from the blower. Therefore, the manufacturing process concerning blasting and 3D additive manufacturing can be performed simultaneously. That is, since it operates and functions efficiently, it is possible to find manufacturing merits such as labor cost reduction and construction period reduction.

  Further, in the inert gas circulation blasting apparatus B3 according to the embodiment shown in FIG. 4, the media storage tank 22A and the media storage tank 22B are arranged side by side, not on the lower side of the cabinet 12. This is because the height of the entire blasting apparatus can be kept low by arranging a plurality of media storage tanks side by side rather than arranging them in series on the lower side of the cabinet 12. If the overall height of the blasting device can be reduced, the stability of the device in the event of a natural disaster such as an earthquake will be eliminated, and the operator will not have to work on a stand to carry out the blasting work. Can also be secured. That is, it is possible to design the apparatus in consideration of the safety of the apparatus and the operator. In particular, when the workpiece is a modeled article made of a metal material, the mass becomes considerable depending on the size. Therefore, the working efficiency can be improved by keeping the head to the cabinet low.

  Further, in this embodiment, the crushed material (medium) 25B crushed by blasting is conveyed to a separating unit 42 (separating device) arranged side by side. The separation unit 42 is configured to separate and extract the crushed material from the gas, and an apparatus that does not cause a pressure loss in the gas flow or has a small pressure loss is preferably used. In the present embodiment, a louver type dust separation device that separates (or classifies) gas and crushed material (medium) 25B using a plurality of louvers 43 is used. In particular, in the louver type dust separation device according to the present embodiment, the crushed material that has fallen without passing between the louvers 43 falls into the lower accommodation space 47 and is accumulated. Therefore, a wall 46 that separates the gas that passes between the louvers 43 and the gas that has descended downward is formed so that the gas that has entered the housing space 47 does not flow into the piping toward the cyclone. The housing space 47 is partitioned. Thereby, the space (accommodating space 47) where the crushed material falls is closed, and the situation where the separated crushed material is blown up by an unintended gas flow can be eliminated. In addition, a pulverized material dropping port exists at the lower end side of the separation space existing in the louver 43. The falling port prevents the dust from rolling up and falls as shown in FIG. It is also desirable to provide a conical check member 48 so that the crushed material does not flow backward. By providing such a check member, it is possible to reduce the possibility that the crushed material existing in the separation space or the accommodation space will again flow into the separation space.

  The separated crushed material (medium) 25B falls into the media storage tank 22A provided on the lower side of the separation unit 42, and is classified into smaller crushed materials (small) by the classification unit 23 in the media storage tank 22A. Is done. The small crushed material (small) is mixed with the gas output from the blower by the mixer 27 and transferred to the projection unit 13 as the shot material 14. The gas separated by the separation unit 42 is transferred to the dust collecting device 17 and then circulated as an energy source of the airflow energized by the blower 26.

Further, as in an inert gas circulation blasting apparatus B4 shown in FIG. 5, the flow of gas in the cabinet 12 can be controlled so that dust does not easily stay in the cabinet. That is, the inert gas circulation blasting apparatus B4 shown in FIG. 5 has the same basic configuration as that of the third embodiment shown in FIG. 4, but the gas discharged from the blower 26 is supplied to the mixer. 27 is divided into a first system 28 that reaches the projection unit 13 through 27 and a second system 44 that supplies gas from the upper part of the cabinet 12 without passing through the mixer 27. According to this configuration, the gas transferred to the upper portion of the cabinet 12 through the second system 44 can discharge the airflow toward the workpiece 11. And since the gas in a cabinet is discharged | emitted from the lower side, in the cabinet 12, the airflow which goes from the top to the bottom is produced, and the dust produced in the cabinet 12 by a blast operation | work can be discharged | emitted effectively. it can. As a result, it is possible to reduce dust floating in the cabinet as much as possible and to ensure a good field of view in the blasting operation. If the visibility can be secured satisfactorily, a safer and more reliable blasting operation can be performed, and a highly accurate processed product 11 can be provided.

B1, B2, B3, B4 Inert gas circulation blasting device 11 Processed product 12 Cabinet 13 Projection unit 14 Shot material 15 Cyclone 16 Dust collector 17 Dust collector 18 Piping 19 Inert gas cylinder 20 Inactive gas flow direction 21 Gas flow direction 22A, 22B Media storage tank 23, 42 Classification unit 24 Rotary valve 25A Crushed material (large)
25B crushed material (medium)
25C crushed material (small)
26 Blower 27 Mixer 28 First System 29, 44 Second System 30 Opening 31 Oxygen Analyzer 32 Window Part 33 Supply Port 34 Sieve Net 35 Suction Port 36 Filter 37 Rotor 38 Casing 39 Inlet Port 40 Exhaust Port 41 3D Laminate Modeling Technical equipment 42 Separating part 43 Louver

Claims (5)

A cabinet for storing processed products;
A projection unit that projects a shot material by an air flow on a processed product housed in the cabinet,
A blower for generating an air flow for energizing the shot material;
A blasting device comprising a dust collector that sucks gas in the cabinet and collects dust in the gas,
An inert gas circulation blasting apparatus, wherein the cabinet is filled with an inert gas, and the inert gas circulates through the blower, the cabinet, and the dust collector.
The crushed product of the processed product crushed by the projected shot material is at least partially used as the shot material,
The inert gas circulation blasting apparatus according to claim 1, wherein a media storage tank is provided below the cabinet to store a crushed product of the processed product accumulated in the cabinet.
A rotary which is a valve device that controls the flow rate of the crushed material by rotating at least one of the outlet side of the crushed material of the processed product generated in the cabinet and the inlet side of the crushed material in the media storage tank. The inert gas circulation blasting device according to claim 1 or 2, wherein a valve is provided.
The pulverized product produced in the cabinet includes a classification unit that classifies the crushed material by size, shape, and / or weight, and a plurality of media storage tanks that store the crushed material.
The inert gas circulation blast device according to any one of claims 1 to 3, wherein the plurality of media storage tanks are arranged in parallel or in series.
It is equipped with a mixer for charging the pulverized product produced in the cabinet into the gas discharged from the blower,
The gas discharged from the blower is branched into a first system that reaches the projection unit through the mixer, and a second system that is supplied into the cabinet without passing through the mixer,
The suction port of the gas which goes to the dust collector in the said cabinet exists near the processed goods accommodated in the cabinet rather than the supply port to the said 2nd system cabinet. An inert gas circulating blasting apparatus according to claim 1.