Surface treatment method of structure, method for removing deposits in manufacturing apparatus of powder product, and method for manufacturing powder product

Abstract

The present invention uses a blasting medium containing a first powder as a main component, which is a powder having a substance with a hardness equal to or less than that of a member to be refurbished. A mixture of the blasting medium and a gas is ejected in a band shape from a nozzle having a substantially rectangular ejection port while adjusting the flow rate. The ejected mixture functions as a lapping tool for removing dirt, and the refurbished surface of the lower layer or the periphery of the dirt on the surface of the member to be refurbished is exposed without being ground, and roughening processing is performed to form fine irregularities on the refurbished surface.

Description

Technical Field

[0001] This invention relates to a surface treatment method for refurbishing structures by removing contamination from the surface of components with adhering substances or deterioration, and a sandblasting apparatus used in the surface treatment of structures. Furthermore, this invention relates to a method and apparatus for cleaning granular adhering objects attached to tools used in manufacturing equipment for granular products such as sugar, and a method and apparatus for manufacturing granular materials using this method and apparatus. Background Technology

[0002] The surfaces of outdoor building components and other structures deteriorate and become contaminated due to exposure to wind, rain, dust, sunlight, etc. As mentioned above, when the surfaces of structural components are contaminated, cleaning is performed to remove the contaminants in order to renovate the surface. As a cleaning method, sandblasting is known, which involves spraying a fluid such as water onto the surface of the component at high pressure and high speed. In addition, sandblasting includes dry sandblasting (for example, see Patent Document 1) which uses a gas such as air as a driving fluid for spraying abrasive (sandblasting medium) to grind the contaminated parts, and wet sandblasting (for example, see Patent Documents 2 and 3) which uses a liquid such as water.

[0003] In addition, the surfaces of components in indoor structures may also be soiled. For example, in structures such as manufacturing equipment located indoors in a factory, there may be instances where manufactured goods adhere to the surfaces of the components that make up the equipment due to the operation of the equipment.

[0004] Specifically, this illustrates a scenario where the apparatus used in manufacturing granular products (powdered products) has the manufactured powdered particles attached to it. Sugar is used as an example of a powdered product. Sugar can be broadly classified into refined sugar and molasses-containing sugar. For instance, Patent Document 4 discloses a method for manufacturing refined sugar. According to Patent Document 4, raw sugar (raw sugar) is produced from harvested sugarcane or sugar beets, and this raw sugar is refined into granulated sugar through processes such as washing, cleaning, and crystallization in a factory. The refined sugar is then stored in different storage silos or similar containers depending on the product.

[0005] Furthermore, in sugar factories, for example, when storing refined sugar in silos, elevators or vibrating conveyors consisting of buckets and chains are used to move the sugar vertically or horizontally. Sugar can adhere to the drive components of these elevators or conveyors. However, if sugar adheres to the drive components, it will rub and solidify under high pressure at the sliding parts of the drive components. The solidified sugar will then be heated by further friction, causing it to brown and discolor. It is undesirable for this discolored sugar to be mixed into the finished product.

[0006] Therefore, in the past, a sugar removal process was regularly performed to remove sugar adhering to the drive parts. Specifically, the drive parts to be removed from the equipment were disassembled and immersed in boiling water, thereby dissolving and removing the adhering sugar. On the other hand, the solution containing dissolved sugar was heated to evaporate the water, thereby causing the sugar to precipitate out and be used for sugar refining.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Registration No. 7025770

[0010] Patent Document 2: Japanese Patent Registration No. 6963261

[0011] Patent Document 3: Japanese Patent Application Publication No. 2018-075706

[0012] Patent Document 4: Japanese Patent Application Publication No. 2003-61700 Summary of the Invention

[0013] The problem the invention aims to solve

[0014] However, in the case of purifying outdoor structures through sandblasting, the following challenges exist. Specifically, sandblasting requires optimizing treatment conditions based on the target object and purpose, necessitating complex research. For instance, various types of sandblasting media exist, as do the driving fluids and spraying conditions. The types of sandblasting media, driving fluids, and spraying conditions are interrelated, exhibiting adaptability in combination. Furthermore, the purification objective, site environment, and characteristics of the target object must be considered when selecting the type of sandblasting media, driving fluid, and spraying conditions. As mentioned above, obtaining the optimal sandblasting treatment conditions inherently requires consideration of various parameters.

[0015] However, determining the treatment conditions by considering all these various parameters is a very tedious task. Therefore, treatment conditions with parameters that can be applied to a certain range are usually selected, that is, universal treatment conditions. For example, slightly increasing (or decreasing) the decontamination removal capacity can be selected to apply to a variety of objects with similar characteristics. However, if universal treatment conditions are selected as described above, the decontamination removal capacity will often be excessive or insufficient depending on the object, thus affecting the workability on site.

[0016] Furthermore, when sandblasting is used to clean the surfaces of components of intricate buildings (structures) of high value, such as temples and shrines, which require careful handling, it is sometimes necessary to minimize damage to the component itself or its surroundings. Additionally, it is required to remove dirt while preserving historically valuable tool marks or carving marks (hereinafter referred to as "processing marks"). In such cases, conventional sandblasting methods have struggled to perform the delicate operation of removing surface dirt such as processing marks (e.g., less than mm) formed on the component's surface. In other words, it is difficult to perform the delicate process of removing surface dirt along the fine irregularities of the processing marks and renovating the component while retaining its irregularities without eliminating them.

[0017] Next, the sugar removal process for cleaning indoor structures presents the following challenges. Firstly, the sugar removal process described above, which requires disassembling the drive components, is extremely time-consuming. Secondly, heating the solution containing molten sugar to precipitate it is time-consuming and energy-intensive, increasing costs. Furthermore, when sugar removal is performed in this manner, the components immediately come into direct contact with each other at the sliding parts of the drive components. This increases the possibility of metal particles detaching from the sliding parts and becoming mixed into the product, necessitating a separate "sprinkling" process (sprinkling powdered sugar onto the sliding parts of the drive components), further complicating conventional sugar removal processes. Moreover, this problem is not limited to refined sugar; it also exists in the cleaning of manufacturing equipment containing molasses. Furthermore, the same problem exists not only in sugar manufacturing plants but also in salt manufacturing plants when removing salt adhering to parts, and in various processes within factories manufacturing a wide variety of powdered products.

[0018] Therefore, the object of the present invention is to solve at least one of the above-mentioned problems. That is, the object is to provide a surface treatment method for a structure, and a sandblasting apparatus, which allows for easy determination of the treatment conditions when the structure is cleaned by sandblasting. Furthermore, the object is to provide a method and apparatus for removing powder adhering to tools used in manufacturing equipment for granular products, which allows for easy removal of powder particles adhering to them, and a method and apparatus for manufacturing granular products including these methods and apparatus.

[0019] Solution for solving the problem

[0020] The first aspect of the present invention provides a surface treatment method for a structure that refurbishes components by removing contamination from the surfaces of components constituting the structure and exposed to the outside. The method uses a blasting medium containing a first granular material having a hardness equal to or less than that of the component as its main component, and employs a blasting apparatus comprising: a nozzle that blows the blasting medium toward the surface of the component using gas as a driving fluid; a hollow tube that supplies a mixture of the blasting medium and the gas to the nozzle; and a flow rate adjustment unit that adjusts the flow rate of the mixture supplied from the hollow tube to the nozzle. The method uses the following nozzle as the blasting medium... The nozzle has a base portion and a top portion. The base portion is connected to the hollow tube and is tubular. The top portion extends from the base portion through the middle portion to the front of the middle portion and forms a generally rectangular nozzle with the long sides spaced 0.5 mm to 1.5 mm apart. The flow rate of the mixture is adjusted to expose the surface of the component. The mixture is blown onto the surface of the component, thereby making the ribbon-like mixture ejected from the nozzle function as a scrubbing tool to remove the dirt. The dirt is removed and the refurbished surface of the component, which is the lower layer or the periphery of the dirt on the surface, is exposed without being ground. A fine roughening process is performed on the refurbished surface to form an uneven surface.

[0021] As described above, by using a blasting medium consisting of granular material with a hardness equal to or less than that of the component to be refurbished, the option of the blasting medium to be used can be easily determined for each component. Furthermore, a mixture of gas and blasting medium is ejected from a nozzle with a generally rectangular slit shape, the distance between the long sides being 0.5 mm to 1.5 mm, and blown towards the component to be refurbished. Preferably, the nozzle is a rectangular shape (e.g., an oval shape) with straight long sides and rounded corners (long sides being curved). The abrasive ejected from such a nozzle forms a thin ribbon of blasting medium that moves in the same direction as the nozzle's operating direction, thus functioning as a slender, dynamic "abrasive tool." In such an "abrasive tool," the blasting medium also reaches fine recesses such as treatment marks, colliding with the component to remove dirt. On the other hand, after colliding with the component, the flow rate of the blasting medium decreases and the particle size decreases, thereby preventing the refurbished surface of the component from being ground down.

[0022] Here, the surface of the component being processed contains deteriorated or contaminated areas that need to be removed (dirt), and hardened areas that form the refurbished surface. The dirt is relatively fragile compared to the hardened areas. These dirt and hardened areas are adjacent to each other at intervals of mm or μm. In conventional sandblasting, it is difficult to perform fine processing such as removing (sweeping) dirt without grinding the hardened areas that form the refurbished surface on component surfaces with unevenness less than mm, such as processing marks. In this invention, the mixture described above is sprayed from the aforementioned nozzle, thereby enabling the sprayed ribbon-like mixture to function as a sweeping tool capable of sweeping corresponding to fine unevenness.

[0023] At this point, if a flow regulating valve or similar device is installed in the flow path supplying the mixture to the nozzle, the flow rate of the mixture can be adjusted, thereby controlling the spraying conditions (either the spray volume or the spraying speed, or both). This allows control over the intensity of the abrasion performed using the "sweeping tool" ejected from the nozzle. Therefore, by adjusting the spraying conditions, the intensity of sandblasting is adjusted to avoid grinding hardened areas beneath or around the contaminated layers. This allows the removal of fine contaminants smaller than a millimeter, and for hardened areas, they can be exposed without grinding, thus creating a refurbished surface for refurbishing components.

[0024] Here, fine particles from the sandblasting medium collide with the exposed refurbished surface, creating tiny depressions (approximately tens to hundreds of μm in diameter). This roughening process, creating micro-level unevenness on the refurbished surface, achieves this effect. By roughening the refurbished surface in this manner, when coatings or similar substances are applied, they adhere more firmly or become more impregnated, resulting in more reliable surface refurbishment of the component.

[0025] As described above, in this invention, it is possible to control the removal of minute contaminants (within mm) from the surface of the component to be processed without removing the solid portion forming the refurbished surface, and it is also possible to roughen the refurbished surface. Therefore, it is possible to remove contaminants while maintaining the minor unevenness of the component surface, which may have processing marks (within mm).

[0026] The surface treatment of the present invention is preferably performed by adjusting the blasting conditions to a minimum of 10 round trips, preferably 7 round trips, and more preferably 5 round trips, on the component surface. This is because if the number of round trips of the nozzle on the component surface increases, the amount of blasting media and power used increases, leading to an undesirable increase in dust generated during surface treatment. On the other hand, there is no particular limitation that the minimum number of times the nozzle moves relative to the component surface is 1 or more (half a round trip). However, if the blasting conditions of the mixture are excessively intensified to remove contaminants by reducing the number of round trips of the nozzle on the component surface, the abrasion intensity becomes too strong, increasing the risk of the treatment marks disappearing or the surface of the component being ground to the point of needing refinishing. Therefore, it is preferable to adjust the blasting conditions so that the number of round trips of the nozzle required for contaminant removal is 1 or more.

[0027] In the first method, the aforementioned component may be wood, and the aforementioned first powdery material may be produced using a plant-based blasting medium with an air-dried specific gravity greater than 0.5.

[0028] Therefore, it is easy to select a suitable sandblasting medium for sandblasting wood surfaces. Furthermore, it is preferable that the first granular material, which is the main component of the sandblasting medium used, has a curved shape. This is because it appropriately removes the weakened and soiled portions, and the curved first granular material inhibits damage to the intact portions of the base material (component) beneath the soiled portions. Additionally, the sandblasting medium may contain a second granular material as a secondary component, consisting of (A) a plant-based sandblasting medium with an air-dried specific gravity of 0.5 or less, or (B) a mineral-based medium. In cases where the component is coated and the coating deteriorates, the presence of the second granular material allows for the removal of the deteriorated layer on the active film in the coating, easily exposing the wood grain containing the active film beneath the deteriorated layer of the component.

[0029] In the surface treatment method of the present invention, the mixture of the blasting medium and the driving fluid functions like a long, thin, strip-shaped abrasive tool, capable of contacting the minute irregularities and gaps between components. Therefore, blasting can be performed on each component constituting the structure while maintaining its constituent state. That is, as described above, each component of the structure, even those with irregularities and gaps, can be treated while still forming the structure, suppressing damage to other components. Therefore, the time required for disassembling and reassembling the structure can be saved in the blasting treatment of its constituent components.

[0030] As another aspect of the present invention, the surface treatment method for the structure may involve refurbishing the component by removing contamination from the surface of the component constituting the structure and exposed to the outside. The structure is a manufacturing apparatus for producing granular products ingested into a living organism. The component's surface is contaminated by granular deposits generated during the manufacturing process of the granular product in the manufacturing apparatus. A sandblasting treatment apparatus is used, employing a sandblasting medium containing a first granular material formed from a substance of the same type as the deposits, as the main component. This sandblasting treatment apparatus includes: a nozzle that blows the sandblasting medium toward the surface of the component using gas as a driving fluid; and a hollow tube that connects the sandblasting medium to the surface of the component. The gas mixture is fed to the nozzle, and the nozzle has a base portion and a top portion. The base portion is connected to the hollow tube and is tubular. The top portion extends from the base portion through the middle portion to the front of the middle portion and forms a generally rectangular nozzle with the long sides spaced 0.5 mm or more and 1.5 mm or less apart. The mixture is blown onto the surface of the component, thereby making the strip of mixture ejected from the nozzle function as a scrubbing tool to remove the dirt. The dirt is removed and the refurbished surface of the component, which is the lower layer or the periphery of the dirt on the surface, is exposed without being ground, and a fine roughening process is performed on the refurbished surface to form an uneven surface.

[0031] Therefore, by using a material of the same type as the adhering substance as the blasting medium, the adhesion force (affinity) of materials of the same type can be utilized to remove contaminants. Furthermore, parts can be cleaned while still assembled in the manufacturing equipment, eliminating the need for disassembly. Additionally, by using a material of the same type as the manufactured powder (granular product) as the blasting medium, excess powder adhering to the parts can be removed, and a spreading process is also performed. This "spreading process" is, for example, a process of spreading powder onto the sliding parts of a drive component and allowing it to adhere; preferably, powder with a particle size smaller than that of the granular product is used. This "spreading process" is also an example of the aforementioned "roughening process" that forms fine irregularities on the refurbished surface. In this specification, the process of forming fine irregularities (e.g., less than mm) on the surface of a component is referred to as "roughening process." Roughening processes include cases where fine irregularities are formed by creating fine recesses on the surface of the component, and cases where fine irregularities are formed by adhering powder. In this specification, when it is necessary to distinguish between the two situations, the former will be referred to as "roughening by forming a recess" and the latter as "roughening by adhering to a powdery substance".

[0032] In the above-described manner, it is preferable that the hardness of the blasting medium is lower than that of the component. By using a substance with a hardness lower than that of the component as the blasting medium, even when a mixture of the blasting medium and the driving fluid (gas) is forcefully blasted, the component can be prevented from being ground (abraded), and the dirt such as the deposits can be removed (sweeped) by utilizing the peeling force of the blasting medium, which is of the same type as the deposit. Especially when a large amount of deposits are attached to the component to be treated and its surface is not exposed, it is sometimes desirable to increase the flow rate of the mixture to enhance the sweeping function of the "sweeping tool" formed by blasting the mixture. In this case, by using a substance with a hardness lower than that of the component as the blasting medium, surface treatment can continue without changing the blasting conditions of the mixture, even if the surface of the component is exposed during the treatment process. However, it is preferable to provide a flow rate adjustment unit that adjusts the flow rate of the mixture supplied from the hollow tube to the nozzle, and if the surface of the component is exposed during the treatment process, adjust (change) the flow rate of the mixture to perform surface treatment by blowing (blasting).

[0033] The effects of the invention

[0034] According to the surface treatment method and sandblasting apparatus of the present invention, the treatment conditions for cleaning a structure by sandblasting can be easily determined. In particular, according to the surface treatment method and sandblasting apparatus of the present invention, the refurbished surface after removal of dirt (e.g., intact parts called "wood grain" under deteriorated wood, undeteriorated solid winter rings, black rust layer formed under red rust as dirt, etc.) will not disappear or be ground away, and the refurbished surface can be exposed.

[0035] Furthermore, the method for removing contaminants in a manufacturing apparatus for powdered or granular products according to the present invention can easily remove contaminants adhering to the tools used in the manufacturing apparatus. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating a process example of a surface treatment method.

[0037] Figure 2 This is a flowchart illustrating a process for manufacturing refined sugar from raw sugar.

[0038] Figure 3 This is a schematic diagram showing the structure of an air blasting device that can be used in the sugar removal method of this embodiment.

[0039] Figure 4 (A) is a top view showing the entire spray nozzle. Figure 4 (B) is a side view of the injection nozzle. Figure 4 (C) is a three-dimensional view showing the area near the nozzle of the injection nozzle magnified.

[0040] Figure 5 This is a diagram illustrating the sugar removal operation performed by the operator.

[0041] Figure 6 (A) and Figure 6 (B) is a schematic diagram showing the structure of a jet nozzle with a lamp installed. Detailed Implementation

[0042] (Implementation Method 1)

[0043] The surface treatment method and sandblasting apparatus for the structure of the present invention will be described below. Furthermore, the method described below is only one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiment, and additions, deletions, and modifications to the structure can be made without departing from the spirit of the invention.

[0044] The surface treatment method of the present invention uses a sandblasting medium primarily composed of a first particulate matter when removing contamination from the surface of a component constituting a structure and exposed to the outside. This first particulate matter has a hardness equal to or less than that of the component, and is preferably a substance that will not pollute the environment even if dispersed into it. That is, such as... Figure 1 As shown in the flowchart, the surface treatment method includes: a step (step S10) of selecting granular material with a hardness equal to or less than that of the component based on the type or condition of the component being treated and considering its hardness; a step (step S20) of selecting a substance from the granular material that is the same type as the contaminant or component; and a step (step S30) of removing contaminants by blasting the sandblasting medium selected in steps S10 and S20 onto the surface of the component under predetermined conditions. Furthermore, steps S10 and S20 can be interchanged or omitted.

[0045] Here, the blasting medium selected in step S10 is a substance that will not pollute the environment even if it is dispersed into the environment, such as a substance derived from natural resources. Specifically, both plant-based and mineral-based blasting media are suitable. In particular, plant-based blasting media are biodegradable, and it is easier to select the hardness, adjust the particle size and shape according to the type of component being treated, making them preferred. In addition, plant-based blasting media are suitable not only for components made of wood, but also for components made of ceramics such as earthenware and pottery, or minerals such as concrete and stone, as well as components made of metals such as iron and copper, and components made of polymer materials such as synthetic resins and rubber, among a wide range of other components. When removing deposits or dirt, the blasting medium is preferably a powdery substance of the same type as the dirt, with a hardness lower than that of the component being treated but higher than that of the dirt. Two or more blasting media can be mixed, and it is suitable to use a plant-based blasting medium as the main component and a blasting medium with a different hardness than the main component as a secondary component.

[0046] Furthermore, when the contamination is an adhering substance that covers the component to the extent that it does not expose the surface of the component, it is appropriate to select a blasting medium of the same type as the contamination in step S20. This is particularly true in manufacturing equipment where the structure is a powdery product (hereinafter also referred to as "ingested material") that is ingested by humans or animals, and where the components constituting the manufacturing equipment are contaminated by powdery adhering substances (e.g., powdery products or powders with the same composition but different particle sizes) generated during the manufacturing process of the powdery product. In such cases, it is appropriate to select a blasting medium composed of the same components as the adhering substance as the "blasting medium of the same type as the contamination". Examples of "ingested material" include sugar, salt, seasonings, other foods, and pharmaceuticals. Furthermore, when the adhering substance is a mixture of powdery particles of various components, the component only needs to be the same as at least one of the powdery particles.

[0047] In step S20, the selection range of the blasting medium can be set to a substance of the same type as the component, rather than the same type of contamination. That is, a substance of the same type as the contamination or component can be selected as the blasting medium. Here, when the contamination or component is classified as wood, ceramic or stone, metal, polymer, or ingested material, the blasting medium composed of materials included in the corresponding classification is considered to be of the same type. In addition, within the same classification, the similarity does not need to reach the level of further subdivision of the type (except for ingested materials). For example, when the contamination or component is beech or cypress wood, the blasting medium of the same type can be a blasting medium composed of beech or cypress wood, but it is not limited to this. For example, if the target component is a high-hardness pine or beech, a lower-hardness cedar can be selected. The air-dried specific gravity of plant-based blasting media varies depending on the plant species (see Patent Document 2), and there is a tendency for a higher air-dried specific gravity to be harder. Therefore, the air-dried specific gravity can be used as an indicator of hardness to determine the blasting medium. Plant-based blasting media should ideally use materials with a specific gravity greater than 0.5 as the first granular material, and then mix materials with a specific gravity less than 0.5 as the second granular material, depending on the type and condition of the component being treated. Examples of suitable plant-based blasting media for the first granular material include walnut, peach, or apricot seed shells, or corn cobs.

[0048] As the first particulate material, in order to suppress damage to the parts near the components of the structure, as well as to suppress damage to the intact parts of the components, a substance with the same or lower hardness as the component being treated is selected as the main component of the blasting medium. On the other hand, in cases where the contaminated part deteriorates and becomes relatively hard, a first particulate material that is the same type as the contaminating material and has a higher hardness than the contaminating material but a lower hardness than the component can be selected as the main component of the blasting medium.

[0049] Furthermore, the term "specific gravity" here can be determined by considering the actual state (moisture content, etc.) of each blasting medium selected via processes S10 and S20 during its use in the blasting process. Preferably, the blasting medium is a mixture blown onto the target component as a mixture with the gas used as the driving fluid, preferably air that has been dehumidified through drying or other processes. This is because if the blasting medium contains moisture, it will adhere to the inside of the nozzle or other parts of the nozzle, or clump together, hindering its function as a sharp abrasive tool and resulting in a ribbon-like spray pattern.

[0050] Furthermore, the so-called "main component" of a blasting medium refers to the type of blasting medium that produces a greater number of particles than any of the secondary components. Therefore, in blasting equipment, when the amount of a certain type of powder in the blasting medium tank for ejection from the nozzle exceeds the amount of any other type of powder, the type of powder is considered the main component, and the type of powder is considered a secondary component. While this also depends on the number of types of powder used as secondary components, typically, the proportion of the type of powder forming the main component in the total blasting medium is between 30% and 100%.

[0051] More specifically, examples of the first particulate material that becomes the main component of the blasting medium can be given as follows: When the components constituting the structure are wood, a plant-based blasting medium with an air-dried specific gravity greater than 0.5 is more suitable as the first particulate material that becomes the main component.

[0052] Regarding the "air-dried specific gravity" of plant-based blasting media, when the blasting media is wood, the apparent specific gravity when the water content is approximately 15% by weight can be used; that is, the ratio of the weight of wood with approximately 15% by weight water content to the weight of water with the same volume as the wood. Furthermore, when the blasting media is a plant other than wood, the ratio can be used when the water content is 5% by weight or more and 10% by weight or less, and the water content actually used in the blasting process.

[0053] Furthermore, regarding the so-called "curved" shape, if it is confirmed under magnification, such as with a microscope, that it is a shape with the corners significantly removed compared to granular blasting media composed of freshly crushed plant material, then it conforms to this shape. There are no particular limitations on the method used to make it curved. As an example, one method is as follows: Angular granular blasting media is placed in a metal stirring roller with protrusions such as blades on its inner surface, and the roller is rotated and stirred at a speed of 60–100 rpm for approximately 20–30 minutes with the rotating shaft horizontal or tilted at less than 45 degrees.

[0054] Furthermore, as the aforementioned plant-based blasting medium, a blasting medium with an average median particle size of 0.01 mm or more and 2.5 mm or less can be used, and a blasting medium with an average median particle size of 0.02 mm or more and 0.8 mm or less is more suitable. This diameter of blasting medium can be obtained by screening the particles using a vibrating screen equipped with a micron-sized sieve. Additionally, the particle size of the obtained blasting medium can be measured, for example, using a laser diffraction / scattering particle size distribution measuring device.

[0055] In addition to the main components described above, the surface treatment method of the present invention may also include a second particulate material as a secondary component. More specifically, examples of the second particulate material that serves as a secondary component of the blasting medium include: When the components constituting the structure are coated wood with a deteriorated surface, a second particulate material composed of (A) a plant-based blasting medium with an air-dried specific gravity of 0.5 or less, or (B) a mineral-based medium, is suitable as a secondary component. In this case, the surface treatment method uses a blasting medium containing both the first and second particulate materials to remove the deteriorated layer on the active film of the coating of the component as dirt, thereby exposing the wood grain of the component containing the active film beneath the deteriorated layer.

[0056] Furthermore, the mineral-based medium described above can be formed using one or more materials selected from the group consisting of stone powder, sand, sodium bicarbonate, calcium carbonate, shell powder, glass powder, and ceramic powder. In this invention, the term "mineral-based medium" typically refers to a medium composed of naturally occurring inorganic crystalline substances, including artificially generated inorganic crystalline substances, as well as biological minerals such as shells and teeth, and substances like opal that, even if amorphous, are generally considered to be included in minerals.

[0057] The surface treatment method of the present invention selects a sandblasting medium in the manner described above (S10, S20), and then uses a driving fluid to blow the selected sandblasting medium onto the surface of the component under predetermined conditions to remove the aforementioned contamination (step S30). Here, the "predetermined conditions" of step S30 will be explained.

[0058] First, the predetermined conditions include the use of a sandblasting apparatus having a hollow tube, a nozzle, and a flow adjustment unit. More specifically, the sandblasting apparatus has a nozzle that blows sandblasting media onto the surface of a component using gas as a driving fluid, a hollow tube that delivers a mixture of sandblasting media and gas to the nozzle, and a flow adjustment unit that adjusts the flow rate of the mixture supplied from the hollow tube to the nozzle. Furthermore, as the nozzle, a nozzle can be used that has a tubular base portion connected to the hollow tube, and a tip portion having a generally rectangular nozzle with long sides spaced 0.5 mm to 1.5 mm apart, extending from the base portion through a middle portion to the front of the middle portion. As an example of such a sandblasting apparatus, the following description can be used. Figure 3 and Figure 4 The disclosed structure.

[0059] Furthermore, the aforementioned predetermined conditions include: using the nozzle of the sandblasting device described above, adjusting the flow rate of the mixture to expose the surface of the component, and blowing the mixture onto the surface of the component. It also includes: through the aforementioned blowing, causing the ribbon-like mixture ejected from the nozzle to function as a scraping tool for removing contaminants, removing contaminants and exposing the underlying or peripheral refurbished surface of the component on the surface of the component without grinding, and performing a fine roughening process to form micro-undulations on the refurbished surface.

[0060] Furthermore, the aforementioned surface treatment method can also spray sandblasting medium onto the surface of a component while the component is still part of the structure. For example, even when sandblasting components such as lintels or windows used for ventilation or lighting between the ceiling and doorway in a temple or shrine building that are part of the building and have carvings, it is not necessary to disassemble them from the building; the sandblasting can be performed while they are still in use. Additionally, for example, in the case of a sugar elevator used to transport sugar in a sugar factory, it is not necessary to disassemble the buckets and chains that make up the elevator; they can be sandblasted while the elevator is still in its functional state.

[0061] Based on the surface treatment method described above, suitable treatment conditions for the target object can usually be easily selected from a large number of parameters, including the type of blasting medium. Furthermore, after selecting steps S10 and S20, the blasting medium or various treatment conditions can be further optimized considering the condition of the contaminant or component, the working environment, etc. Moreover, since the treatment conditions determined in the above manner are suitable for the surface treatment of the target component, the possibility of damage to the intact parts or surrounding parts of the component is reduced compared to using conventionally more general treatment conditions. Therefore, it is also possible to perform blasting treatment on the target component while it is still forming a structure. In addition, since the same blasting medium as the type of contaminant or component is used, as described above, in sugar factories and other similar applications, blasting treatment can be performed while maintaining the structural components, without disassembling the component.

[0062] The following section will further explain the sandblasting process in manufacturing equipment for materials ingested in the body, such as sugar factories and salt factories. As in the case of the sugar factory mentioned above, when the powdered product manufactured is sugar and the sugar adhering to the components constituting the elevator or other structures is removed, white sugar with relatively low hygroscopicity can be used as the first powdered material as the sandblasting medium.

[0063] (Implementation Method 2)

[0064] Next, referring to the accompanying drawings, an embodiment of the present invention for removing deposits adhering to a manufacturing equipment for powdery products, as one specific example of the above-described surface treatment method, will be described. Furthermore, the method described below is only one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiment, and additions, deletions, and modifications to the structure can be made without departing from the spirit of the invention. Additionally, the following description, primarily using a method for removing sugar from parts of a sugar manufacturing equipment, can also be performed in the same manner for methods for removing salt from parts of a salt manufacturing equipment, including methods for removing salt from parts of a salt manufacturing equipment, to remove deposits from a manufacturing equipment for powdery products composed of materials ingested from the body.

[0065] <Sugar Manufacturing Process>

[0066] First, the manufacturing process of refined sugar will be explained. Figure 2 This is a flowchart illustrating an example of the process of manufacturing refined sugar from raw sugar. For example... Figure 2 As shown, in the production of refined sugar, raw sugar from sugarcane or sugar beets from various regions is collected and stored in a warehouse (process S1). The raw sugar stored in the warehouse is transported to the refining plant via conveyors or the like. In the plant, as part of the sugar washing process (process S2), after stirring the raw sugar and sugar solution, it is separated into crystals and molasses containing impurities, and the obtained crystals are dissolved in hot water to make a sugar solution.

[0067] Next, as a cleaning step (step S3), lime milk and carbon dioxide are added to the sugar solution obtained in the sugar washing step to react, causing impurities in the sugar solution to coagulate during the reaction. The sugar solution is then filtered to obtain a yellowish-brown transparent sugar solution. Furthermore, the yellowish-brown transparent sugar solution is passed through an ion exchange resin to further remove impurities, and the resulting colorless transparent sugar solution is sterilized by irradiating it with ultraviolet light and then concentrated.

[0068] In the subsequent crystallization process (process S4), seed sugar is added to the concentrated sugar solution for crystallization. Then, in the refining process (process S5), the mixture of crystals and sugar solution (so-called sugar paste) produced in the crystallization process is separated into crystals and syrup by a separator. The extracted crystals are dried, cooled, and refined, and then stored in temperature-controlled storage silos or the like, depending on the type of product. In the final packaging / shipping process (process S6), the sugar stored in the storage silos or the like in the above manner is sieved to ensure that the particle size falls within a predetermined range, packaged into bags appropriate for the intended use, and shipped.

[0069] Here, for example, when storing sugar refined through the refining process (process S5) in a storage silo, the sugar is moved vertically and horizontally by a lift and a vibrating conveyor consisting of a bucket and a chain. If the sugar adheres to the drive parts of the lift and conveyor, the sugar will be fixed at the sliding parts of the drive parts due to high-pressure friction.

[0070] The adhering material removal method of the present invention is applicable, for example, to removing adhering materials fixed to drive parts. However, the application of the adhering material removal method of the present invention is not limited to this; it can be used in the manufacturing processes of various powdery and granular products such as salt and seasonings, and pharmaceuticals. Taking sugar production as an example, it is applicable to the removal of sugar adhering to equipment used in all sugar (refined sugar and molasses-containing) manufacturing equipment, including equipment used in molasses-containing manufacturing equipment. Furthermore, it can be used not only for drive parts but also for removing sugar adhering to various other parts, floors, walls, etc.

[0071] <Air blasting device>

[0072] Figure 3 This is a schematic diagram illustrating the structure of an air blasting device (blasting treatment device), an example of an adhering substance removal apparatus that can be used in the sugar removal method of this embodiment. Furthermore, this blasting treatment device can be used not only in the sugar removal method but also for reference purposes. Figure 1 In the surface treatment method of the structure described in Embodiment 1, air blasting apparatus of this embodiment is exemplified as using air as the driving fluid for blasting, but other gases can also be used as the driving fluid. Figure 3 As shown, the air blasting device 1 includes an air compressor 2, a blasting medium tank 3, a spray nozzle 4, and hoses 5 and 6 connecting them. The air compressor 2, the blasting medium tank 3, and the hoses 5 and 6 constitute a blasting medium supply device 1A that supplies blasting medium to the spray nozzle 4.

[0073] Air compressor 2 generates dry compressed air and ejects it from nozzle 2a. For example, a compressor with several kW power at three-phase 200V can be used. A dryer for drying the air can be built into air compressor 2 or installed independently of it. For example, a gas storage tank (not shown) can be installed between air compressor 2 and sandblasting media tank 3 to store compressed air and dry the driving fluid (in this case, air). In this configuration, the upstream end of hose 5 is connected to nozzle 2a of air compressor 2, and the downstream end of hose 5 is connected to sandblasting media tank 3. Hose 5 is, for example, a flexible tube with a predetermined strength to withstand the pressure of the compressed air ejected from nozzle 2a.

[0074] The blasting medium tank 3 includes a tank body 3a with a predetermined internal volume, and an opening that can be opened and closed via a cover 3b is provided on the upper part of the tank body 3a. The blasting medium is introduced into the tank body 3a through this opening. In addition, an inlet 3c is provided on the upper side of the tank body 3a, and the downstream end of the hose 5 mentioned above is connected to the inlet 3c. A supply port 3d is provided at the bottom of the tank body 3a, and the upstream end of the hose 6 is connected to the supply port 3d. The downstream end of the hose 6 is connected to the jet nozzle 4 via a valve unit 7. The valve unit 7 has a flow adjustment part, i.e., an operating tool 7b, for adjusting the flow rate of the mixture of driving fluid (dried air) and blasting medium, and a tube body 7a as a hollow tube. The hose 6, like the hose 5, is made of, for example, a flexible tube, and has a predetermined strength to withstand the pressure of air containing the blasting medium supplied from the supply port 3d (hereinafter referred to as "blasting air"), as well as flexibility (softness) for easy operation by the operator. In addition, the blasting medium tank 3 includes a pressure gauge 8. For example, a pressure gauge 8 is installed on the upper side of the tank body 3a, which can measure and output (display) the internal pressure of the tank body 3a.

[0075] Furthermore, granular sugar (or "salt" as described below) used as a sandblasting medium is prone to agglomeration due to moisture. Therefore, an oscillator or agitator can be installed in the tank body 3a of the sandblasting medium tank 3. This applies vibration or agitation to the medium within the tank body 3a, thereby suppressing agglomeration. As a result, the granular medium, or even if agglomerated, the medium with a relatively small diameter, can be smoothly discharged from the supply port 3d. Such an oscillator or agitator can be, for example, a known machine such as a turbine oscillator that uses air flowing through the hose 5 to rotate a turbine with an eccentrically mounted counterweight to generate vibration.

[0076] Valve unit 7 is located between the downstream end of hose 6 and the jet nozzle 4, and includes a pipe body 7a and an operating tool 7b. One open end of the pipe body 7a is connected to the downstream end of hose 6, and the other open end is connected to the jet nozzle 4. The blasting air supplied from hose 6 is delivered to the jet nozzle 4 through the pipe body 7a. A valve (not shown) is provided inside the pipe body 7a to open and close the internal flow path. The valve is actuated by the operator using the operating tool 7b. By actuating the valve, the internal flow path of the pipe body 7a can be opened and closed, and the opening degree can be continuously adjusted between fully open and fully closed, thereby adjusting the jetting conditions of the mixture of driving fluid and blasting medium.

[0077] The spray nozzle 4 is a so-called flat nozzle, with a flat spray orifice 44. Figure 4 (A) is a top view showing the entire spray nozzle 4. Figure 4 (B) is a side view of the injection nozzle 4. Figure 4(C) is a perspective view showing an enlarged view of the area near the nozzle 44 of the spray nozzle 4. Furthermore, when explaining the configuration of the spray nozzle 4, regarding the concept of direction, the length direction of the spray nozzle 4 (the direction of airflow for sandblasting) is defined as the front-to-back direction, the side view direction as the left-to-right direction, and the direction orthogonal to both as the up-down direction. Additionally, in Figure 4 (A) and Figure 4 In (B), the dashed line in the figure represents the outline of the internal flow path of the injection nozzle 4.

[0078] like Figure 4 As shown in (A), the injection nozzle 4 has a base portion 41 connected to the valve unit 7, an intermediate portion 42 extending forward from the base portion 41, and a tip portion 43 extending further forward from the intermediate portion 42. In this embodiment, the injection nozzle 4 is made of metal, and the base portion 41, the intermediate portion 42, and the tip portion 43 are integrally formed.

[0079] The base portion 41 is tubular, and its inner diameter is the same as or approximately the same as the inner diameter of the tube body 7a of the valve unit 7. The middle portion 42 extends from the front end of the base portion 41 and, when viewed from the side, has a wedge shape in which the thickness (height) gradually decreases from the rear end to the front end. More specifically, as... Figure 4 As shown in (B), the middle portion 42 of the injection nozzle 4, when viewed from the side, has an isosceles triangular shape with the upper end 42a and the lower end 42b forming a hypotenuse and the front end as the vertex. Therefore, in side view, the upper end 42a of the middle portion 42 intersects the upper end 41a of the base portion 41 at a predetermined angle, and the lower end 42b of the middle portion 42 also intersects the lower end 41b of the base portion 41 at the same predetermined angle.

[0080] The top portion 43 is a further extension from the front end of the middle portion 42, and its vertical external dimension (height dimension) H1, when viewed from the side, is approximately constant from the rear end 43a to the front end 43b. On the other hand, as... Figure 4 As shown in (A), regarding the left-right external dimensions (width dimensions) of the top portion 43 when viewed from above, the width dimension W1b of the front end 43b is greater than the width dimension W1a of the rear end 43a, and gradually increases proportionally from the rear end 43a toward the front end 43b. That is, the top portion 43 is fan-shaped or, when viewed from above, is an isosceles trapezoidal shape with the rear end 43a as the upper base and the front end 43b as the lower base. Similarly, regarding the width dimension of the inner diameter of the top portion 43 of the spray nozzle 4, it is also preferable that the width dimension W2b of the front end 43b is greater than the width dimension W2a of the rear end 43a, and gradually increases proportionally from the rear end 43a toward the front end 43b.

[0081] like Figure 4As shown in (C), a jet nozzle 44 is formed at the front end 43b of the top portion 43. The jet nozzle 44 is a flat opening with a vertical dimension (height dimension) H2 that is smaller than its horizontal dimension (width dimension) W2b in the horizontal direction (first direction). Furthermore, the height dimension H2 of the jet nozzle 44 is a constant value that is approximately the same at any position in the horizontal direction (width direction).

[0082] <Sugar Removal Operation>

[0083] Next, the sugar removal operation using the air blasting device 1 described above will be explained. Figure 5 This is a schematic diagram illustrating a sugar removal operation performed by an operator. Figure 5 In this process, sugar is moved upwards by a lifting platform 100. The lifting platform 100 is also called a bucket lifting platform, and therefore includes a bucket 101 and a chain 102. The bucket 101 and chain 102 described above are examples of drive components that remove sugar.

[0084] The bucket 101 is a container of predetermined capacity with an opening at the top, made of stainless steel or synthetic resin. Here, the chain 102 is a roller chain, configured to connect pairs of outer plates 102a, 102a and pairs of inner plates 102b, 102b via rollers 102c with inserted pins and bushings. This chain 102 suspends the bucket 101 from the left and right sides and transports it upwards.

[0085] In the factory, the space is divided into an area where sugar is moved via elevator 100 and an area where operators (OPs) and other workers perform their tasks. Figure 5 In this case, the transfer area A1 is the area driven by the elevator 100, and the work area A2 is the area where the operator performs OP operations. Furthermore, the transfer area A1 and the work area A2 are separated by a door 103, and the door 103 is equipped with an openable and closable window 104. Figure 5 As an example, the sugar removal operation is shown through the open window 104.

[0086] During the sugar removal operation, the transfer of sugar using the elevator 100 is interrupted. Preferably, the sugar piled in the bucket 101 of the elevator 100 is in a discharged state. During the sugar removal operation, operator OP loads a predetermined amount of blasting medium (granular sugar) into the tank body 3a of the blasting medium tank 3 and closes the cover 3b. Then, the air compressor 2 is driven, and the pressure gauge 8 confirms that the internal pressure of the tank body 3a of the blasting medium tank 3 has reached a predetermined pressure. Meanwhile, the operating tool 7b of the valve unit 7 is set to the closed state. Then, as... Figure 5As shown, the operator (OP) drapes the hose 6 extending from behind their right shoulder, holds the top of the hose 6 with their left hand, and holds the spray nozzle 4 with their right hand. In this position, the operator points the spray nozzle 4 towards the target object and operates the valve unit 7's operating tool 7b from the closed state to the open state. This causes the blasting medium, sugar, to be sprayed from the spray nozzle 4 and directed towards the target object.

[0087] In the sugar removal operation, the elevator 100 can be driven upwards or downwards at a predetermined speed. This speed can be the same as, slower than, or faster than, the conveying speed during sugar production. By driving the elevator 100 while blowing sugar, the sugar removal operation can be smoothly advanced, and the blasting medium (sugar) can be blown towards the sliding part of the driving component. Therefore, sugar adhering to the sliding part can be removed, and the blasting medium (sugar) can be "spread" onto the sliding part.

[0088] Furthermore, after the sugar removal process is completed, the elevator 100 is driven to circle the machine a predetermined number of times, shaking off (discarding) any residual blasting media (sugar) accumulated in the bucket 101 and other areas. This prevents the sugar used as the blasting media from mixing into the sugar produced after the sugar removal process. Additionally, the residual sugar can be disposed of by blowing it with pressurized air that does not contain the blasting media.

[0089] On the other hand, there is a possibility that moisture in the factory may cause sugar to adhere more firmly to the drive parts, making it impossible to sufficiently remove the adhered sugar even by simply blowing sandblasting media. This may occur, for example, if sugar removal is to be performed after the factory has been shut down for several days. In this case, it is preferable to subject the blowing of the sandblasting media to a predetermined change.

[0090] As an example of the variation, one could exemplify this by causing the spray nozzle 4 to vibrate with a predetermined amplitude and a predetermined period while spraying the abrasive medium. More specifically, the spray nozzle 4 could be made to repeatedly reciprocate within a predetermined angular range, such as in the up-down or left-right directions, while spraying the abrasive medium. This action could be achieved by the operator (OP) moving their hand holding the spray nozzle 4, or by a mechanical structure such as a reciprocating movement mechanism.

[0091] In the case of a mechanical implementation, an example is a mechanism that rotatably supports the middle section of the injection nozzle 4, and connects a crank to the rear end of the injection nozzle 4, which is then rotated using an electric motor or the like. Alternatively, an oscillator that generates vibrations of a predetermined period can be fitted into the middle of the injection nozzle 4 or the hose 6. As the oscillator, a turbine-type oscillator as described above or other known electric oscillators can be used.

[0092] Another example of the variation can be the intermittent spraying of blasting media from the spray nozzle 4. More specifically, the concentration of the blasting media sprayed from the spray nozzle 4 is intermittently varied. This can be achieved by adjusting the supply amount of blasting media to the spray nozzle 4. For example, a flow regulating valve is installed at any point along the route from the tank body 3a to the spray nozzle 4, such as at the supply port 3d of the blasting media tank 3 or midway along the hose 6, to adjust the flow rate of the blasting media (and air) supplied to the spray nozzle 4. Furthermore, the opening of this flow regulating valve is repeatedly changed over time. Thus, the concentration of the blasting media can be intermittently varied.

[0093] (Other implementation methods)

[0094] Hereinafter, techniques applicable to one or more of the above embodiments 1 to 2 will be described.

[0095] <Specifications for various sugar removal methods>

[0096] Various preferred specifications of the sugar removal method using the air blasting device 1 as described above will be explained.

[0097] The preferred sugar used as a blasting medium is one with an average particle size of 200 μm or more and 500 μm or less, and a coefficient of variation of 0.20% or more and 0.30% or less. The coefficient of variation is the value obtained by dividing the standard deviation by the average value and multiplying by 100%, and here it represents the degree of deviation in particle size. In this embodiment, white sugar with an average particle size of 493 μm and a coefficient of variation of 0.28% is used. However, the type of sugar used as a blasting medium is not limited to one. For example, two or more types of sugar can be mixed and used as a blasting medium. In this case, sugar with a relatively large particle size used for sugar removal can be mixed with sugar with a relatively small particle size used for spreading to use as a blasting medium.

[0098] Furthermore, as not limited to sugar, the granules used in the blasting medium are preferably selected to have a particle size and specific gravity that are larger than the granules adhering to the manufacturing equipment.

[0099] The spray nozzle 4 is not limited to the sugar removal method of the present invention. In the surface treatment method of the present invention, it is also preferable that the height dimension (dimension in the second direction) H2 of the spray nozzle 44 is 1.6 times or more and 4.0 times or less of the average particle size of the blasting medium. In particular, to function as a gas-solid mixing abrasive tool by spraying a mixture of powdery blasting medium with a median particle size of μm in a ribbon shape, the spray nozzle is preferably a relatively thin, approximately rectangular slit with a height dimension (distance between the long sides of a rectangle) of 0.5 mm or more and 1.5 mm or less, preferably 0.7 mm or more and 1.0 mm, and with a curved, especially arc-shaped, short side. In this embodiment, a spray nozzle 44 with a height dimension H2 of 0.8 mm is used. Furthermore, the inner diameter of the tip portion 43 of the spray nozzle 4 is preferably such that the width dimension W2b of the front end 43b is greater than the width dimension W2a of the rear end 43a, and gradually increases proportionally from the rear end 43a towards the front end 43b. For example, preferably, the ratio of W2b / W2a is 1.1 or more and 1.5 or less. In this embodiment, the length of the top portion 43 is 150 mm, the width dimension W2a of the inner diameter of the rear end 43a is 25 mm, and the width dimension W2b of the inner diameter of the front end 43b is 35 mm (W2b / W2a = 1.4).

[0100] For the gas pressure used to spray the sandblasting medium, the internal pressure of the sandblasting medium tank 3 is preferably 0.4 MPa or more and 0.9 MPa or less.

[0101] The sugar removal method of Embodiment 2 can be used in manufacturing equipment for various types of sugar, including refined sugar and sugar containing molasses, and is particularly suitable for drive parts of manufacturing equipment for refined sugar. Since refined sugar contains invert sugar (containing fructose as a single component), it has high hygroscopicity and easily adheres to various parts of the manufacturing equipment, making sugar removal a labor-intensive process in the past. Therefore, by applying the above-described sugar removal method, a unique effect of significantly reducing labor and costs can be achieved.

[0102] The embodiments described above are examples, and the structure of the present invention is not limited thereto. For example, the type of powdery material to be removed, the type of granular material used as the blasting medium, the structure of the air blasting device (attachment removal device) 1 including the structure of the blasting nozzle 4, and the gas pressure used for blasting the blasting medium are not limited to the specifications described above, and other specifications may also be used. For example, depending on the type of attachment, the attachment location, and the blasting angle (angle of entry), a blasting nozzle whose cross-section of the blasting orifice is not approximately rectangular may also be used. As such a blasting nozzle, the inner diameter of the blasting orifice may, for example, be 1.5 mm or more and 10 mm or less. Furthermore, the object to be removed is not limited to elevators or conveyors, and other structures of the manufacturing equipment may also be used as the object, and it is not limited to drive parts.

[0103] Furthermore, while Embodiment 2 specifically describes a method for removing sugar from parts in a sugar manufacturing apparatus, the same method can also be applied to a method for removing salt from parts in a salt manufacturing apparatus. In this case, granular salt can be used as the blasting medium. This method can also be applied to methods for removing adhering substances in manufacturing apparatuses for food products such as seasonings containing amino acids or other substances as powders, and for pharmaceutical products such as medicines containing chemical substances as powders. Additionally, given the possibility of foreign matter contamination during the manufacturing process, particularly foreign matter from the manufacturing equipment caused by wear, this method is applicable to manufacturing apparatuses for powdery products where it is highly necessary to avoid this situation, such as powdery products ingested by animals, including humans.

[0104] According to Embodiment 2, apart from the disassembly of equipment that is not required for removing the adhering substances, the emission of carbon dioxide associated with the chemical substances or energy consumption used in the manufacturing process of powder particles can be reduced by not using or reducing the use of solvents such as hot water used for removing the adhering substances. This invention is particularly suitable for situations where a "spreading treatment" is required after the adhering substances have been removed.

[0105] <Modified example of sandblasting equipment>

[0106] When implementing the surface treatment method of the present invention, as already explained, it is not necessary to disassemble the components constituting the structure, and sandblasting can be performed while maintaining the state of the constituting structure. On the other hand, in this case, there are situations where the object is in shadow or otherwise difficult to identify visually. Therefore, a lamp that irradiates the component sprayed with sandblasting medium can be provided at the nozzle of the sandblasting apparatus. Figure 6 (A) and Figure 6 (B) is a schematic diagram showing the structure of the spray nozzle 4 with the lamp installed. Additionally, in Figure 6 (A) and Figure 6In (B), the structure of the spray nozzle 4, except for lamp 50, is the same as that of the previously used nozzle. Figure 4 The spray nozzle 4 described is the same as the flat nozzle.

[0107] exist Figure 6 In case (A), a lamp 50 is provided on the side of the flat top portion 43 of the spray nozzle 4 in the width direction (left-right direction). The lamp 50 has a cylindrical body portion 51, the axis of which is approximately parallel to the length direction (front-back direction) of the spray nozzle 4. The lamp 50 has a support portion 52 provided at the rear of the body portion 51, which supports the body portion 51 at a predetermined interval relative to the top portion 43 of the spray nozzle 4. A vertical through hole 52a is formed in the support portion 52, and the support portion 52 is fixed to the top portion 43 by wrapping a strip 53 that passes through the through hole 52a around the top portion 43 of the spray nozzle 4.

[0108] exist Figure 6 In case (B), a lamp 50 is provided above the flat tip portion 43 of the spray nozzle 4 in the thickness direction (vertical direction). This lamp 50 is also for reference. Figure 6 The lamp 50 described in (A) has the same structure, including a body portion 51, a support portion 52 having a through hole 52a, and a belt 53. Furthermore, the support portion 52 is fixed to the top portion 43 by wrapping the belt 53, which passes through the through hole 52a, around the top portion 43 of the spray nozzle 4.

[0109] Figure 6 (A) or Figure 6 The lamps 50 shown in (B) are all fixed to the spray nozzle 4, and the spray direction of the blasting medium ejected from the spray port 44 of the spray nozzle 4 is approximately parallel to the optical axis. With this configuration, the light from the lamps 50 can illuminate the component being blasted with the blasting medium during the blasting operation, thus making it easy to visually confirm the removal status of contaminants and improving workability. Furthermore, in Figure 6 (A) and Figure 6 In (B), an example is shown where a lamp 50 is mounted on the top portion 43 of the spray nozzle 4, but it is not limited thereto. For example, it may also be mounted on the base portion 41 of the spray nozzle 4.

[0110] Alternatively, an angle adjustment mechanism can be provided at the connection between the lamp body 51 and the support 52 to arbitrarily change the optical axis of the lamp 50. For example, various torque hinges, torque ball joints, etc., capable of maintaining any angle through friction can be used as the angle adjustment mechanism.

[0111] <Note>

[0112] Based on the description of the above embodiments, the following methods are disclosed.

[0113] (First method)

[0114] A surface treatment method for a structure involves refurbishing the components by removing contamination from the surfaces of the components constituting the structure and exposed to the outside. The method uses a sandblasting medium containing a first granular material having a hardness equal to or less than that of the component as its main component. The sandblasting apparatus includes: a nozzle that blows the sandblasting medium onto the surface of the component using gas as a driving fluid; a hollow tube that supplies a mixture of the sandblasting medium and the gas to the nozzle; and a flow rate adjustment unit that adjusts the flow rate of the mixture supplied from the hollow tube to the nozzle. The following nozzle is used as the nozzle: It has a base portion and a top portion. The base portion is connected to the hollow tube and is tubular. The top portion extends from the base portion through the middle portion to the front of the middle portion and forms a generally rectangular nozzle with the long sides spaced 0.5 mm to 1.5 mm apart. The flow rate of the mixture is adjusted to expose the surface of the component. The mixture is blown onto the surface of the component, thereby making the ribbon-like mixture ejected from the nozzle function as a scrubbing tool to remove the dirt. The dirt is removed and the refurbished surface of the component, which is the lower layer or the periphery of the dirt on the surface, is exposed without being ground. A fine roughening process is performed on the refurbished surface to form an uneven surface.

[0115] (Second method)

[0116] In the surface treatment method of the structure described in the first method, the aforementioned component is wood, and the aforementioned first granular material is treated with a plant-based sandblasting medium with an air-dried specific gravity greater than 0.5.

[0117] (Third method)

[0118] In the surface treatment method of the structure described in the first or second method, the component is coated wood with deteriorated surface, the sandblasting medium contains a second particulate matter as a secondary component consisting of (A) a plant-based sandblasting medium with an air-dried specific gravity of 0.5 or less, or (B) a mineral-based medium, the deteriorated layer on the active film in the coating of the component is removed as the aforementioned dirt, and the wood grain of the component containing the active film under the deteriorated layer is exposed as the aforementioned renovation surface.

[0119] (Fourth method)

[0120] In any of the first to third methods of surface treatment of a structure, the mixture is sprayed onto the surface of the component in a spray manner while the component constitutes the structure.

[0121] (Fifth method)

[0122] A surface treatment method for a structure involves refurbishing the components by removing contamination from the surfaces of the components constituting the structure and exposed to the outside. The structure is a manufacturing apparatus for producing granular products ingested by organisms. The components are contaminated with granular deposits generated during the manufacturing process of the granular products in the manufacturing apparatus. The method utilizes a sandblasting medium containing a first granular material of the same type as the deposits as its main component, and a sandblasting apparatus comprising: a nozzle that uses gas as a driving fluid to blow the sandblasting medium onto the surface of the component; and a hollow tube that delivers a mixture of the sandblasting medium and the gas. The above-mentioned nozzle is used, and the following nozzle is used as the above-mentioned nozzle, which has a base end portion and a top end portion. The base end portion is connected to the above-mentioned hollow tube and is tubular. The top end portion extends from the base end portion through the middle portion to the front of the middle portion and forms a generally rectangular spray nozzle with the long sides being 0.5 mm or more and 1.5 mm or less apart. The above-mentioned mixture is blown onto the surface of the component, thereby making the strip-shaped mixture sprayed from the above-mentioned spray nozzle function as a scrubbing tool to remove the above-mentioned dirt. The dirt is removed and the refurbished surface of the component at the lower layer or the periphery of the dirt on the surface is exposed without being ground, and a fine roughening treatment is performed to form an uneven surface on the refurbished surface.

[0123] (Sixth method)

[0124] In the surface treatment method of the structure described in the fifth method, the aforementioned granular product is granulated sugar, and the aforementioned first granular material of the aforementioned sandblasting medium is white granulated sugar.

[0125] (Seventh Method)

[0126] A sandblasting apparatus is used for surface treatment of a structure that renovates components by removing dirt from the surface of components constituting the structure and exposed to the outside. The sandblasting apparatus includes: a medium tank for storing sandblasting medium in the form of powder, which is a substance with a hardness equal to or less than that of the component; a nozzle for spraying the sandblasting medium onto the component using a driving fluid when the component constitutes the structure; and a lamp installed at the nozzle to irradiate the component with the sandblasting medium sprayed onto it.

[0127] (Eighth Method)

[0128] A method for removing contaminants involves removing granular contaminants attached to a manufacturing equipment for producing granular products, wherein a granular material of the same substance as the contaminant is used as a blasting medium, the blasting medium is sprayed from a nozzle and blown onto a part provided in the manufacturing equipment for the granular products and which has the granular contaminant attached.

[0129] (Ninth Method)

[0130] In the method for removing deposits described in the eighth method, the powdered product is sugar, and the average particle size of the sugar used as the sandblasting medium is 200 μm or more and 500 μm or less, and the variation coefficient is 0.20% or more and 0.30% or less.

[0131] (Tenth Method)

[0132] In the attachment removal method described in the eighth or ninth method, the nozzle used is a nozzle with a flat shape having a spray orifice that is smaller than the size of the second direction which is orthogonal to the first direction, and the size of the second direction in the spray orifice is more than 1.6 times and less than 4.0 times the average particle size of the blasting medium.

[0133] (Eleventh Method)

[0134] In the attachment removal methods described in the eighth to tenth methods, the gas pressure used to spray the sandblasting medium is 0.4 MPa or more and 0.9 MPa or less, based on the pressure gauge inside the sandblasting medium tank that contains the sandblasting medium and delivers it to the nozzle.

[0135] (Twelfth method)

[0136] In the method for removing deposits described in the ninth method, the sugar manufactured by the aforementioned manufacturing equipment is high-quality white sugar, and the granulated sugar used as the aforementioned sandblasting medium is white sugar.

[0137] (Thirteenth Method)

[0138] In the method for removing deposits described in the eighth method, the powdery product is salt, and the sandblasting medium is granular salt.

[0139] (Fourteenth Method)

[0140] An adhering material removal device is provided in a manufacturing equipment for producing granular products to remove granular adhering materials attached to the manufacturing equipment. The adhering material removal device includes: a nozzle that sprays a sandblasting medium; a sandblasting medium supply device that supplies particulate matter of the same substance as the adhering material to the nozzle as the sandblasting medium; and a measuring device that measures the spraying condition of the sandblasting medium sprayed from the nozzle.

[0141] (Fifteenth method)

[0142] A method for manufacturing a powdery product, comprising manufacturing equipment for manufacturing powdery products and an adhering substance removal device as described in the fourteenth method, wherein the adhering substance is removed from the manufacturing equipment by an adhering substance removal method as described in any one of the eighth to thirteenth methods, thereby manufacturing the powdery product.

[0143] (Sixteenth Method)

[0144] A manufacturing apparatus for a powder or granular product, wherein the manufacturing apparatus for the powder or granular product includes an adhering substance removal device as described in the fourteenth method.

[0145] Industrial availability

[0146] This invention can be suitably applied to a method and apparatus for removing powdery deposits adhering to manufacturing equipment for powdery products, and to a method and apparatus for manufacturing powdery materials using the method and apparatus.

[0147] Explanation of reference numerals in the attached figures

[0148] 1: Air blasting device (attachment removal device); 2: Air compressor; 3: Blasting medium tank; 4: Blasting nozzle; 44: Blasting port.

Claims

1. A method for removing contaminants, comprising removing granular contaminants adhering to manufacturing equipment for manufacturing granular products, wherein, Using a blasting medium of the same material as the adhering substance, but with a hardness higher than the adhering substance and a hardness equal to or less than that of the component of the part attached to the granular product manufacturing equipment, and having an arc shape, the blasting medium is sprayed from a nozzle and blown toward the part to remove the granular adhering substance and perform a roughening treatment equivalent to a spreading process. This spreading process is to prevent the metal particles from falling off due to direct contact between the parts at the sliding parts of the granular product manufacturing equipment.

2. The method for removing attachments according to claim 1, wherein, The powdered product is granulated sugar. The average particle size of the granulated sugar used as the sandblasting medium is above 200 μm and below 500 μm, and the variation coefficient is above 0.20% and below 0.30%.

3. The method for removing attachments according to claim 1, wherein, As the nozzle, a nozzle with a flat shape having a jet orifice that is smaller than the size of a second direction orthogonal to the first direction compared to the size of the first direction is used, wherein the size of the jet orifice in the second direction is more than 1.6 times and less than 4.0 times the average particle size of the blasting medium.

4. The method for removing attachments according to claim 1, wherein, The gas pressure used to spray the blasting medium is 0.4 MPa or more and 0.9 MPa or less, as measured by a pressure gauge inside the blasting medium tank that contains the blasting medium to be delivered to the nozzle.

5. The method for removing attachments according to claim 2, wherein, The sugar produced by the manufacturing equipment is high-quality white sugar, and the granulated sugar used as the sandblasting medium is white sugar.

6. The method for removing attachments according to claim 1, wherein, The powdered product is salt, and the sandblasting medium is granular salt.

7. A method for manufacturing a powder or granular product, wherein, The powdered product is manufactured by removing the adhering material from the manufacturing equipment where the powdered product is manufactured and the powdered adhering material is attached, using the method for removing the adhering material according to any one of claims 1 to 6.

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