Powder supply device

Abstract

To provide a powder supply device capable of supplying powder at a stable supply rate, even when treating powder of high flowability.SOLUTION: A powder supply device supplies powder together with carrier gas, and has agitation blades agitating the powder stored in a powder storage chamber, a supply panel 38 having recessed parts 36 for receiving the agitated powder and transporting the powder received in the recessed parts 36 to a prescribed position P by rotation, and a suction unit sucking the powder transported to the prescribed position from a suction port together with the carrier gas. The supply panel 38 has the multiple recessed parts 36 aligned in a rotation direction R of the supply panel and a suppressing part 39 for suppressing flow of the powder and the carrier gas between the adjacent recessed parts 36 in the rotation direction R of the supply panel.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a powder feeding device. [Background technology]

[0002] Powder feeders that supply powder together with a carrier gas are known as powder sources for DC plasma torches, high-frequency induction thermal plasma devices, etc. Conventional powder feeders include a powder storage chamber that stores powder, a stirring blade that stirs the powder stored in the powder storage chamber, and a feeder plate with grooves that receive powder falling from holes in the powder storage chamber, and are designed to supply the powder that has fallen into the grooves of the feeder plate together with the carrier gas. For example, a powder feeder described in Patent Document 1 is known as an example of this type of powder feeder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-65246 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when handling powder with high fluidity, conventional powder supplying devices are sometimes unable to supply powder at a stable supply rate.

[0005] The present invention has been made to solve the above-mentioned problems, and its object is to provide a powder supplying device that can supply powder at a stable supply rate even when handling powder with high fluidity. [Means for solving the problem]

[0006] The present invention provides a powder supplying device that supplies powder together with a carrier gas, comprising: a powder storage chamber that stores the powder; a stirring blade that stirs the powder stored in the powder storage chamber; a supply board having a recess that receives the powder stirred by the stirring blade and transports the powder received in the recess to a predetermined position by rotation; and a suction unit that sucks the powder transported to the predetermined position by the supply board through a suction port together with the carrier gas. The supply board has a plurality of recesses aligned in the rotation direction of the supply board, and a suppression portion that suppresses the flow of powder and carrier gas between adjacent recesses in the rotation direction of the supply board. [Effects of the Invention]

[0007] According to the present invention, even when handling powder with high fluidity, the powder can be supplied at a stable supply rate. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a powder supplying device according to a first embodiment of the present invention. FIG. [Figure 2] 1 is a plan view showing the configuration of a supply board provided in the powder supplying device according to the first embodiment of the present invention. FIG. [Figure 3] FIG. 3 is a cross-sectional view of the supply board shown in FIG. 2 taken along line III-III. [Figure 4] FIG. 10 is a partial cross-sectional view showing a plurality of recesses expanded in the rotation direction of the supply platen. [Figure 5] FIG. 2 is a plan view showing the arrangement of the powder storage chamber and the supply plate. [Figure 6] FIG. 10 is a diagram showing the relationship between the powder supply rate and the rotation speed of the supply platen. [Figure 7] FIG. 10 is a graph showing the change in powder supply rate over time. [Figure 8] FIG. 10 is a plan view showing a modified example of the supply board in the first embodiment. [Figure 9] FIG. 10 is a plan view showing the configuration of a supply board provided in a powder supplying device according to a second embodiment of the present invention. [Figure 10]FIG. 10 is a diagram (part 1) illustrating an example in which two recesses and two suppressing portions are provided on the supply board in the second embodiment. [Figure 11] FIG. 10 is a diagram (part 2) illustrating an example in which two recesses and two suppressing portions are provided on the supply board in the second embodiment. [Figure 12] FIG. 10 is a diagram (part 3) illustrating an example in which two recesses and two suppressing portions are provided on the supply board in the second embodiment. [Figure 13] FIG. 10 is a diagram (part 1) illustrating an example in which three recesses and three suppressing portions are provided on the supply board in the second embodiment. [Figure 14] FIG. 10 is a diagram (part 2) illustrating an example in which three recesses and three suppressing portions are provided on the supply board in the second embodiment. [Figure 15] FIG. 10 is a diagram (part 3) illustrating an example in which three recesses and three suppressing portions are provided on the supply board in the second embodiment. [Figure 16] FIG. 10 is a view (part 4) for explaining an example in which three recesses and three suppressing portions are provided on the supply board in the second embodiment. [Figure 17] FIG. 10 is a schematic diagram showing the configuration of a powder feeding device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, elements having substantially the same functions or configurations are designated by the same reference numerals, and redundant description will be omitted.

[0010] First Embodiment FIG. 1 is a schematic diagram showing an example of the configuration of a powder supplying device according to a first embodiment of the present invention. 1, powder supplying apparatus 10 is an apparatus that supplies powder together with a carrier gas. Powder supplying apparatus 10 includes a powder storage chamber 32 that stores powder 30, an agitating blade 34 that agitates powder 30 stored in powder storage chamber 32, a supply board 38 that has a recess 36 that receives powder 30 agitated by agitating blade 34 and transports powder 30 received in recess 36 to a predetermined position P by rotation, and a suction unit 40 that sucks powder 30 transported to predetermined position P by supply board 38 through a suction port 50 together with carrier gas.

[0011] The powder storage chamber 32 is a hollow container, also called a hopper, with a capacity large enough to store a predetermined amount of powder 30. The powder storage chamber 32 is cylindrical. The lower end of the powder storage chamber 32 is open so that the powder 30 stirred by the stirring blade 34 can fall into a recess 36 in the feeder plate 38. The upper end of the powder storage chamber 32 is open so that the powder 30 can be introduced into the powder storage chamber 32. The opening at the upper end of the powder storage chamber 32 is closed by an O-ring 31 and a lid 35, thereby sealing the inside of the powder storage chamber 32. The periphery of the feeder plate 38 and a predetermined position P (described below) in the suction unit 40 are also sealed, just like the powder storage chamber 32.

[0012] The agitating blades 34 are located at the bottom of the powder storage chamber 32. Multiple agitating blades 34 are attached to the outer surface of a rotating bracket 42. The rotating bracket 42 is connected to a rotating shaft 46 to which an O-ring 58 is attached. The agitating blades 34 are slightly raised above the base member 20 to prevent them from scraping the top surface of the base member 20. The base member 20 is formed in a disk shape. The powder storage chamber 32 is kept airtight by attaching an O-ring or the like to the connecting portion with the base member 20. The powder storage chamber 32 and the suction unit 40 are attached to a cover member.

[0013] The agitating blades 34 fill the recesses 36 of the supply plate 38 with the powder 30 while agitating the powder 30 contained in the powder storage chamber 32. The rotating bracket 42 is attached to the upper end of the rotating shaft 46. The rotating shaft 46 is rotatably inserted into the base member 20 and rotates according to the drive of a motor (not shown). The rotating bracket 42 is disposed concentrically with the rotating shaft 46 and rotates integrally therewith. An O-ring 58 is attached to the rotating shaft 46 for an airtight seal. The number of agitating blades 34 is at least two, and preferably four. When four agitating blades 34 are provided, the agitating blades 34 are preferably arranged at equal intervals of 90 degrees around the outer surface of the rotating bracket 42. The agitating blades 34 may also be tilted at any angle.

[0014] A stirring member 44 is attached to the rotating bracket 42. The stirring member 44 rotates together with the stirring blades 34 to stir the powder 30 in the powder storage chamber 32 so as to prevent the formation of a bridge of the powder 30 inside the powder storage chamber 32. The stirring member 44 is made of a thin rectangular plate made of, for example, fluororesin and has appropriate flexibility. The stirring member 44 is arranged to rise from the rotating bracket 42. The stirring member 44 is attached at the rotation center of the rotating bracket 42 or at a position offset from the rotation center in the depth direction of FIG. 1.

[0015] The supply plate 38 is a rotating body that feeds the powder 30 in the powder storage chamber 32 into the recess 36 using the stirring blade 34, and supplies the filled powder 30 to the suction unit 40. The supply plate 38 is a so-called disk that is formed in a circular shape when viewed from above.

[0016] FIG. 2 is a plan view showing the configuration of a supply board provided in the powder supplying device according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view of the supply board shown in FIG. 2 taken along the line III-III. As shown in Figures 2 and 3, a shaft connecting portion 37 is formed in the center of the supply platen 38. The shaft connecting portion 37 is a portion for connecting the supply platen 38 and the rotating shaft 48 (Figure 1). The rotating shaft 48 is rotatably inserted into the base member 20 at a position different from that of the rotating shaft 46 described above, and rotates in accordance with the drive of a motor (not shown). The supply platen 38 is disposed concentrically with the rotating shaft 48, and rotates integrally with the rotating shaft 48. An O-ring 59 (Figure 1) for airtight sealing is attached to the rotating shaft 48.

[0017] A plurality of recesses 36 are formed on the outer periphery of the supply platen 38. In the first embodiment, for example, a total of 24 recesses 36 are provided on the supply platen 38. The recesses 36 are formed on the upper surface of the supply platen 38 with their respective openings facing upward. The recesses 36 are located on the same circumference and are arranged at equal intervals in the rotation direction R of the supply platen 38. The predetermined position P described above is set at one location on the circumference where the recesses 36 are arranged, and is located at a location other than where the powder storage chamber 32 and the supply platen 38 overlap. Each recess 36 is formed in a circular shape in plan view. In other words, each recess 36 opens in a circular shape in plan view. By forming a plurality of recesses 36 on the supply platen 38 in this manner, the powder 30 stirred by the stirring blade 34 is filled at a uniform bulk density into each recess 36 by the downward pushing force of the stirring blade 34.

[0018] Each recess 36 is formed by recessing the upper surface of the supply plate 38 into a semicircular cross section. The cross-sectional shape of the recess 36 is not limited to a semicircular shape, and may be, for example, a rectangular or V-shape. When the cross-sectional shape of the recess 36 is semicircular, it is possible to obtain the effects of facilitating the processing of the recess 36 and of making it difficult for the powder 30 to remain in the recess 36 when the powder 30 is sucked from the recess 36.

[0019] FIG. 4 is a partial cross-sectional view showing a plurality of recesses developed in the rotation direction of the supply platen. As shown in FIG. 4, the supply platen 38 has suppression portions 39 between adjacent recessed portions 36 in the rotation direction R of the supply platen 38. The suppression portions 39 are formed to suppress the flow of powder 30 and carrier gas between adjacent recessed portions 36 in the rotation direction R of the supply platen 38. The suppression portions 39 exist as barriers between the recessed portions 36 to prevent adjacent recessed portions 36 from being continuous with each other in the rotation direction R of the supply platen 38. In other words, the suppression portions 39 are formed to separate adjacent recessed portions 36 from each other in the rotation direction R of the supply platen 38. Therefore, the number of recessed portions 36 and the number of suppression portions 39 provided on the supply platen 38 are the same.

[0020] Returning to Figure 1, the explanation will be made again. The supply plate 38 is arranged so as to partially overlap the powder storage chamber 32 when viewed from above. As a result, of the multiple recesses 36 formed in the supply plate 38, some recesses 36 are located inside the powder storage chamber 32, and the other recesses 36 are located outside the powder storage chamber 32. The cover member described above is placed on the base member 20 so as to close the openings of the recesses 36 located outside the powder storage chamber 32. Note that the number, size, spacing, etc. of the recesses 36 provided in the supply plate 38 can be changed as needed.

[0021] The suction unit 40 includes a powder suction pipe 52 and a gas introduction pipe 54. The gas introduction pipe 54 is a pipe that introduces a carrier gas to a predetermined position P. The carrier gas is a compressed inert gas. Examples of inert gases used as the carrier gas include argon, helium, and nitrogen. One end (lower end) of the powder suction pipe 52 opens as a suction port 50. The suction port 50 opens downward at the predetermined position P. The powder suction pipe 52 is a pipe that sucks up the powder 30, which has been transported to the predetermined position P by the supply panel 38, through the suction port 50 together with the carrier gas. The powder 30 sucked up through the suction port 50 is supplied to a destination device (not shown) through the powder suction pipe 52. The destination device may be any device. Specific examples of the destination device include a film formation device using direct current plasma or thermal plasma, as well as a film formation device based on a high-velocity flame spraying method, an aerosol deposition method, a cold spray method, or the like.

[0022] When the supply plate 38 is rotated so that one of the recesses 36 is positioned at a predetermined position P, the suction port 50 of the powder suction pipe 52 is positioned so that at the predetermined position P, the suction port 50 faces downward and the recess 36 faces upward, and they are close to and facing each other in the vertical direction.

[0023] Here, the diameter (inner diameter) of suction port 50 is defined as D1 (mm), and the diameter (opening diameter) of recess 36 is defined as D2 (mm). In this case, if D1 > D2, a portion of suction port 50 will be positioned protruding from recess 36 in the radial direction of supply platen 38, and powder 30 may be sucked into powder suction pipe 52 from the protruding portion, causing an unstable supply rate of powder 30. For this reason, it is preferable that diameter D1 of suction port 50 and diameter D2 of recess 36 satisfy the relationship D1 ≦ D2.

[0024] The powder suction pipe 52 and the gas introduction pipe 54 are arranged in a double-pipe structure directly above the predetermined position P, with the powder suction pipe 52 serving as the inner pipe and the gas introduction pipe 54 serving as the outer pipe. Therefore, the carrier gas is sprayed into the recess 36 from all directions around the outer periphery of the powder suction pipe 52. A gas supply pipe 56 is connected to the gas introduction pipe 54. The gas supply pipe 56 branches off from the gas introduction pipe 54. The gas supply pipe 56 is a pipe that supplies carrier gas to the predetermined position P through the gas introduction pipe 54.

[0025] Next, the operation of the powder feeding device according to the first embodiment of the present invention will be described. First, in the suction unit 40, carrier gas is supplied to a predetermined position P through the gas supply pipe 56 and the gas inlet pipe 54. The carrier gas thus supplied to the predetermined position P flows circumferentially from the outlet at the lower end of the gas inlet pipe 54 to the suction port 50 and is sucked into the powder suction pipe 52. In other words, at the predetermined position P, the carrier gas flows in a circular manner from the inner periphery of the outer gas inlet pipe 54 to the inner powder suction pipe 52.

[0026] Meanwhile, a predetermined amount of powder 30 is placed in the powder storage chamber 32, and the agitating blade 34 and supply plate 38 rotate in this state. As shown in FIG. 5, the supply plate 38 and agitating blade 34 rotate counterclockwise when viewed from above the powder storage chamber 32. As a result, at the bottom of the powder storage chamber 32, the powder 30 is stirred by the agitating blade 34 and dropped into each recess 36. The powder 30 is also scraped off by the agitating blade 34, filling each recess 36 with a fixed amount. The powder 30 thus filled in each recess 36 is transported to a predetermined position P by the rotation of the supply plate 38.

[0027] Furthermore, inside the powder storage chamber 32, the stirring member 44 rotates together with the stirring blade 34. At this time, a portion (the upper portion) of the stirring member 44 is curved and deformed due to centrifugal force generated when the stirring blade 34 rotates. The bending and deformation of the stirring member 44 is a phenomenon caused by the flexibility of the stirring member 44 itself. This bending and deformation of the stirring member 44 causes the portion of the stirring member 44 to slide along the inner wall of the powder storage chamber 32. Furthermore, the shape of the rotating stirring member 44 deforms irregularly due to resistance from contact with the powder 30. Therefore, the stirring member 44 rotates while moving over a wide range within the powder storage chamber 32. As a result, inside the powder storage chamber 32, the stirring member 44 can break up agglomerates of the powder 30, which are the source of agglomerates, before the agglomerates grow. This prevents the formation of bridges of powder 30 inside the powder storage chamber 32. Therefore, almost all of the powder 30 put into the powder storage chamber 32 falls into the recess 36 of the supply plate 38 and can be transported to a predetermined position P by the rotation of the supply plate 38.

[0028] As described above, when the powder 30 filled in the recesses 36 of the supply platen 38 is transported to the predetermined position P by the rotation of the supply platen 38, the powder 30 in the recesses 36 flows circumferentially from the inner circumferential outlet at the lower end of the gas inlet pipe 54 toward the suction port 50. The powder 30 is sucked up through the suction port 50 by the suction force generated when it is sucked into the powder suction pipe 52. The powder 30 sucked up through the suction port 50 travels through the powder suction pipe 52 with the flow of carrier gas and is supplied to the destination device. Furthermore, the multiple recesses 36 formed in the supply platen 38 pass through the predetermined position P in sequence as the supply platen 38 itself rotates. Therefore, the amount of powder 30 supplied per unit time at the predetermined position P depends on the rotation speed (rpm) of the supply platen 38. The rotation speed of the supply platen 38 can be freely changed by controlling the driving conditions of the motor that rotates the supply platen 38 via the rotating shaft 48. Therefore, the rotation speed of the supply platen 38 is one of the parameters for controlling the supply rate (g / min) of the powder 30 supplied to the receiving device by the powder supplying device 10. In this case, it is preferable that the rotation speed of the supply platen 38 and the supply rate of the powder 30 are proportional to each other. At the same time as the rotation of the supply platen 38, the stirring blade 34 is also rotated at a ratio of supply platen:stirring blade = 1:1 to 6. The rotation direction is usually counterclockwise for both the supply platen 38 and the stirring blade 34, but the rotation direction may be in any direction.

[0029] Here, the inventors have conducted extensive research and found that if a circumferential groove (not shown) is formed on the upper surface of supply platen 38 instead of multiple recesses 36, the following problems may occur. These problems will be explained in detail below.

[0030] The circumferential groove is an annular groove that continues in the rotational direction (circumferential direction) of the supply platen 38. Therefore, when a circumferential groove is formed on the upper surface of the supply platen 38, the powder storage chamber 32 and the suction unit 40 are spatially connected through the circumferential groove. Therefore, when handling a powder 30 with high fluidity, such as 64 titanium, the following phenomenon is likely to occur.

[0031] First, with both the agitating blade 34 and the supply plate 38 stopped, a predetermined amount of powder 30 is charged into the powder storage chamber 32, and then carrier gas is supplied to a predetermined position P through the gas supply pipe 56 and the gas inlet pipe 54. In this case, because both the agitating blade 34 and the supply plate 38 are stopped, ideally the supply rate of the powder 30 should be zero, meaning that no powder 30 is supplied from the powder storage chamber 32 to the predetermined position P. However, powder 30 with high fluidity may slide along the circumferential groove of the supply plate 38 to the predetermined position P and be sucked into the powder suction pipe 52, even though the agitating blade 34 and the supply plate 38 are stopped.

[0032] Furthermore, when carrier gas is supplied to predetermined position P through gas supply pipe 56 and gas inlet pipe 54, some of the carrier gas flows into powder storage chamber 32 through the circumferential groove in supply plate 38, filling powder storage chamber 32 with carrier gas. The carrier gas filling powder storage chamber 32 acts to push powder 30 out of powder storage chamber 32, thereby promoting the flow of powder 30 from powder storage chamber 32 to predetermined position P. Even if the supply of carrier gas is stopped after both stirring blade 34 and supply plate 38 are stopped, the carrier gas that has already filled powder storage chamber 32 may push powder 30 into the circumferential groove in supply plate 38, causing it to flow to or near predetermined position P.

[0033] Therefore, when a configuration in which a circumferential groove is formed on the upper surface of the supply plate 38 is adopted, when handling powder 30 with high fluidity, the powder 30 in the powder storage chamber 32 is supplied from the circumferential groove to the predetermined position P at unexpected times or under unexpected circumstances, resulting in an unstable supply rate of the powder 30.

[0034] In contrast to this, the powder supplying device 10 according to the first embodiment of the present invention is able to supply the powder 30 at a stable supply rate even when handling powder 30 with high fluidity. The reason for this will be explained below.

[0035] In the first embodiment of the present invention, a configuration is adopted in which a plurality of recesses 36 are formed on the upper surface of the supply plate 38, and suppression sections 39 are formed between each of the recesses 36. Therefore, when carrier gas is supplied to a predetermined position P through the gas supply pipe 56 and the gas introduction pipe 54, the flow of carrier gas from the predetermined position P toward the powder storage chamber 32 is suppressed by the suppression sections 39. This makes it difficult for the carrier gas to fill the powder storage chamber 32. Furthermore, even if the powder storage chamber 32 is filled with carrier gas, the flow of powder 30 from the powder storage chamber 32 toward the predetermined position P is suppressed by the suppression sections 39.

[0036] Therefore, according to the first embodiment of the present invention, when a predetermined amount of powder 30 is charged into the powder storage chamber 32 with both the agitating blade 34 and the supply plate 38 stopped, and then carrier gas is supplied to a predetermined position P, there is no risk of the powder 30 in the powder storage chamber 32 flowing into or near the predetermined position P. Furthermore, when the supply of carrier gas is stopped after both the agitating blade 34 and the supply plate 38 are stopped, there is no risk of the powder 30 in the powder storage chamber 32 flowing into or near the predetermined position P. Therefore, even when handling powder 30 with high fluidity, it is possible to supply the powder 30 at a stable supply rate.

[0037] The inventors conducted an experiment using the powder supplying apparatus 10 according to the first embodiment of the present invention, and obtained the following results: In the experiment, 64 titanium having an average particle size of about 50 to 100 μm was used as the powder 30.

[0038] FIG. 6 is a diagram showing the relationship between the powder supply rate and the rotation speed of the supply platen. 6, the solid line in the graph indicates theoretical values. The experiment was carried out when the initial amount of powder 30 charged into the powder storage chamber 32 was set to 2 kg and 3 kg. As can be seen from FIG. 6, the experimental results obtained for the relationship between the powder supply rate and the rotation speed of the supply platen were close to the theoretical value, regardless of the difference in the initial amount of powder 30 charged.

[0039] FIG. 7 is a diagram showing the change in powder supply rate over time. In the experiment, the maximum allowable amount of powder 30 was charged into the powder storage chamber 32, and the supply of powder 30 was continued from the start of the supply of powder 30 until the powder 30 in the powder storage chamber 32 was used up. 7, the powder supply rate increased rapidly immediately after the start of supplying the powder 30 and stabilized at around 200 (g / min). The powder supply rate was maintained stable until the powder 30 in the powder storage chamber 32 was depleted. The above experimental results prove that the powder feeding apparatus 10 according to the first embodiment of the present invention can feed even highly fluid powder 30 such as 64 titanium at a stable rate.

[0040] In the first embodiment, when forming the plurality of recesses 36 in the supply platen 38, the recesses 36 are formed to be of the same size (diameter, depth) aligned in a row in the rotation direction R of the supply platen 38. However, the present invention is not limited to this, and recesses 36 of different sizes may be formed in a plurality of rows. For example, as shown in FIG. 8, recesses 36a having a first size may be formed in two rows aligned in the rotation direction R of the supply platen 38, and recesses 36b having a second size smaller than the first size may be formed in a row between them. In this case, the suppression portion 36c is the portion of the circumferential upper surface of the supply platen 38 other than the recesses 36a and 36b.

[0041] Second Embodiment Next, a second embodiment of the present invention will be described. The powder feeding device according to the second embodiment of the present invention differs from the configuration of the first embodiment in that the shape of the recess in the feeding platen is different, as will be explained in detail below.

[0042] FIG. 9 is a plan view showing the configuration of a supply board provided in a powder supplying device according to a second embodiment of the present invention. As shown in FIG. 9 , a plurality of recesses 36A are formed on the outer periphery of the supply platen 38A. In the second embodiment, for example, a total of eight recesses 36A are provided on the supply platen 38. The recesses 36A are formed on the upper surface of the supply platen 38A, each opening upward. The recesses 36A are located on the same circumference and are aligned at equal intervals in the rotation direction R of the supply platen 38. Each recess 36A is formed in the shape of an elongated hole in plan view, with its major axis aligned with the rotation direction R of the supply platen 38 and its minor axis aligned with the radial direction of the supply platen 38. Each recess 36A is formed to have a semicircular cross section recessed from the upper surface of the supply platen 38A. The cross-sectional shape of each recess 36A is preferably semicircular, as in the first embodiment, but is not limited thereto and may be rectangular, V-shaped, or the like.

[0043] Furthermore, the supply platen 38A has suppression portions 39A between adjacent recessed portions 36A in the rotation direction R of the supply platen 38A. The suppression portions 39A are formed to suppress the flow of powder 30 and carrier gas between adjacent recessed portions 36A in the rotation direction R of the supply platen 38A. The suppression portions 39A exist as barriers between the recessed portions 36A so that adjacent recessed portions 36A in the rotation direction R of the supply platen 38A are not continuous with each other. In other words, the suppression portions 39A are formed to separate adjacent recessed portions 36A in the rotation direction R of the supply platen 38A.

[0044] In the second embodiment of the present invention, a configuration is adopted in which multiple recesses 36A are formed on the upper surface of supply plate 38A, and suppression sections 39A are formed between each recess 36A. Therefore, when carrier gas is supplied to predetermined position P through gas supply pipe 56 and gas inlet pipe 54, the flow of carrier gas from predetermined position P toward powder storage chamber 32 is suppressed by suppression sections 39A. This makes it difficult for carrier gas to fill powder storage chamber 32. Even if carrier gas is filled into powder storage chamber 32, suppression sections 39A suppress the flow of powder 30 from powder storage chamber 32 toward predetermined position P. Therefore, according to the second embodiment of the present invention, like the first embodiment, powder 30 can be supplied at a stable supply rate.

[0045] The number, size, and spacing of recesses 36A provided on supply platen 38A can be changed as needed. As for suppression units 39A, it is preferable to provide three or more suppression units 39A at equal intervals in the rotation direction R of supply platen 38A. The reason for this will be explained below.

[0046] First, when two recesses 36A and two suppression units 39A are provided on supply plate 38A, when carrier gas is supplied to predetermined position P with supply plate 38A stopped, the supply of unwanted powder 30 from powder storage chamber 32 to predetermined position P may or may not be effectively suppressed depending on the position at which supply plate 38A stops rotating. Specifically, as shown in FIG. 10, when two suppression units 39A are positioned outside powder storage chamber 32, the supply of unwanted powder 30 from powder storage chamber 32 to predetermined position P can be effectively suppressed. However, when either suppression unit 39A is positioned inside powder storage chamber 32, as shown in FIGS. 11 and 12, the supply of unwanted powder 30 from powder storage chamber 32 to predetermined position P cannot be effectively suppressed.

[0047] In contrast, when three recesses 36A and three suppression units 39A are provided on the supply platen 38A, as shown in FIGS. 13 to 16, at least two suppression units 39A are positioned outside the powder storage chamber 32 regardless of the rotation stop position of the supply platen 38A. This effectively suppresses the supply of unnecessary powder 30 from the powder storage chamber 32 to the predetermined position P. However, the recesses 36A in the second embodiment are formed longer in the circumferential direction than the recesses 36 in the first embodiment. Therefore, as shown in FIG. 16, for example, when one end of one of the recesses 36A is positioned at the predetermined position P, all of the powder 30 filled in the recess 36A may be sucked into the powder suction pipe 52 even when the supply platen 38A is stopped. Therefore, to further stabilize the supply rate of the powder 30, it is preferable that each of the recesses 36 provided on the supply platen 38 is formed in a circular shape in plan view, as described in the first embodiment.

[0048] <Third embodiment> Next, a third embodiment of the present invention will be described. The powder feeding device according to the third embodiment of the present invention differs from the configurations of the first and second embodiments described above in that it includes piping and valves for balancing the pressure in the powder storage chamber with the spatial pressure in the receiving device to which powder is supplied by the suction unit. This will be explained in detail below.

[0049] FIG. 17 is a schematic diagram showing the configuration of a powder feeding device according to the third embodiment of the present invention. 17, as described above, cover member 21 is attached to base member 20, and powder storage chamber 32A and suction unit 40 are attached to cover member 21. Powder storage chamber 32A has a cone-shaped opening at the top so that it can store more powder 30. The opening at the top end of powder storage chamber 32A is closed by lid 33.

[0050] As described above, the suction unit 40 has the powder suction pipe 52 and the gas supply pipe 56. The powder suction pipe 52 is provided with a valve 61. The powder suction pipe 52 is connected to a vacuum chamber 62 provided in the supply destination device via a four-way branch flange 63. The gas supply pipe 56 is provided with a filter 64. The filter 64 is a filter that prevents foreign matter, including the powder 30, from flowing back into the gas supply device 67. The gas supply pipe 56 is connected to a pipe 66 via a coupler 65. The pipe 66 is connected to the gas supply device 67. The gas supply device 67 is a supply source of carrier gas.

[0051] On the other hand, a pipe 70 is connected to the vacuum chamber 62. A pipe 72 is connected to the pipe 70 via a coupler 71, and a pipe 74 is connected to the pipe 72 via a coupler 73. The pipe 74 is connected to the gas supply pipe 56 between the filter 64 and the coupler 65. Two valves 75 and 76 are provided to the pipe 72. The pipe 77 is connected to the pipe 72 between the valves 75 and 76. The pipe 77 is provided with a filter 78. The filter 78 is a filter that prevents foreign matter, including the powder 30, from flowing back into the pipe 77. The pipe 77 is connected to the lid 33 of the powder storage chamber 32A.

[0052] Next, a procedure for supplying powder 30 to vacuum chamber 62 using powder supplying device 10 according to the third embodiment of the present invention will be described. First, all valves 61, 75, and 76 are closed. Next, a predetermined amount of powder 30 is charged into powder storage chamber 32A, and then lid 33 is closed. Next, a vacuum pump (not shown) is driven to maintain a predetermined vacuum pressure (vacuum level) inside vacuum chamber 62. The pressure inside vacuum chamber 62 corresponds to the spatial pressure of the supply destination device.

[0053] Next, valves 75 and 76 are opened. This connects the space inside vacuum chamber 62 to the entire space inside powder supplying device 10, including powder containing chamber 32, via pipes 70, 72, 74, and 77. As a result, the pressure inside vacuum chamber 62 and the pressure inside powder containing chamber 32 are in equilibrium.

[0054] Next, valve 61 is slowly opened, and valves 75 and 76 are closed. Next, gas supply device 67 is driven to supply carrier gas to gas supply pipe 56 through piping 66. Next, stirring blade 34 and supply plate 38 are rotated. As a result, powder 30 is supplied from powder suction pipe 52 through four-way branch flange 63 into vacuum chamber 62.

[0055] In the powder feeding device 10 according to the third embodiment of the present invention, the pressure in the vacuum chamber 62 and the pressure in the powder storage chamber 32 are brought into equilibrium, and under this equilibrium state, powder 30 is supplied to the vacuum chamber 62 by supplying carrier gas. If pressure equilibrium is not achieved, the vacuum chamber 62 will be in a vacuum state and the powder storage chamber 32 will be at atmospheric pressure, creating a pressure difference, which could result in the powder 30 being sucked into the vacuum chamber 62 as soon as the valve 61 is opened, even though no carrier gas is flowing. Therefore, to prevent this from happening, it is preferable to bring the pressure in the vacuum chamber 62 and the pressure in the powder storage chamber 32 into equilibrium.

[0056] The technical scope of the present invention is not limited to the above-described embodiments, but also includes forms in which various modifications and improvements are made within the scope that can derive specific effects obtained by the constituent elements of the invention and their combinations.

[0057] Furthermore, the powder supply device of the present invention is an apparatus that is particularly effective when handling powder 30 with high fluidity, but it is not an apparatus that is specialized for handling such powder 30, and can handle a wide range of powders 30 with various characteristics. [Explanation of symbols]

[0058] 10...Powder feeding device 30…powder 32, 32A... Powder storage chamber 34...Stirring blade 36, 36A, 36a, 36b...recesses 38,38A…Supply board 39,39A…Suppression part 40...Suction unit 50...Suction port 52...Powder suction pipe 54...Gas inlet pipe 61, 75, 76... Valves 66, 70, 72, 74, 77...Piping P...predetermined position R...Rotation direction

Claims

1. A powder feeding device that feeds powder together with a carrier gas, comprising: a powder storage chamber for storing powder; a plurality of stirring blades attached to an outer surface of a rotating bracket provided at the bottom of the powder storage chamber to stir the powder stored in the powder storage chamber; a supply plate having a recess for receiving the powder stirred by the stirring blade, and for conveying the powder received in the recess to a predetermined position by rotation; a suction unit that sucks the powder conveyed to the predetermined position by the supply panel through a suction port together with the carrier gas; a flexible stirring member that is arranged to rise from the rotating bracket and rotates together with the stirring blade inside the powder storage chamber; Equipped with the supply platen has a plurality of recesses aligned in a rotational direction of the supply platen, and has suppression portions for suppressing flows of the powder and the carrier gas between the recesses adjacent to each other in the rotational direction of the supply platen; The stirring member is curved and deformed by the centrifugal force generated when the stirring blade rotates, and slides along the inner wall of the powder storage chamber. Powder feeding device.

2. The suction unit has a gas introduction pipe that introduces a carrier gas to the predetermined position, and a powder suction pipe that sucks up the powder transported to the predetermined position together with the carrier gas from the suction port.

10. The powder feeding apparatus of claim 1.

3. Three or more of the suppressing portions are provided at equal intervals in the rotation direction of the supply platen.

3. A powder feeding apparatus according to claim 1 or 2.

4. Each of the recesses has a semicircular cross section. A powder feeding apparatus according to any one of claims 1 to 3.

5. Each of the recesses is formed in a circular shape in a plan view. A powder feeding apparatus according to any one of claims 1 to 4.

6. When the diameter of the suction port is D1 (mm) and the diameter of the recess is D2 (mm), D1≦D2 is satisfied.

6. A powder feeding apparatus according to claim 5.

7. The powder supply device has a piping and a valve for balancing the pressure in the powder storage chamber with the space pressure of the supply destination device to which the powder is supplied by the suction unit. A powder feeding apparatus according to any one of claims 1 to 6.

8. The stirring member is attached at a position offset from the rotation center of the rotating bracket. A powder feeding apparatus according to any one of claims 1 to 7.

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