Powder ejection mechanism

Abstract

To provide a liquid ejecting mechanism that can spray powder to an object satisfactorily.SOLUTION: A powder ejecting mechanism comprises: a powder supply part 11 that supplies a prescribed supply quantity of powder S1; a powder conveying part 13 that has a flow path 131 of compressed gas G1 extending to cross a vertical direction D1 at a vertical lower part 11 side, and conveys the powder S1 in a conveying direction D21 along the flow path 131, by the compressed gas G1; and a powder input part 12 through which the powder S1 is dropped from the powder supply part 11 into the powder conveying part 13. The powder input part 12 has a powder contact part 12c, provided between an input port 12a and an ejection port 12b for the powder S1, which the powder S1 dropped into the powder input part 12 contacts. The powder contact part 12c is configured to change a motion direction so that at least motion components toward the conveying direction D21 in the flow path 131 are increased by contacting of the powder S1 dropped from the powder input part 12a with the powder contact part 12c and then make the powder to be ejected through the ejection port 12b.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a powder dispensing mechanism. [Background technology]

[0002] In metal pipes such as cast iron pipes used for water supply and sewerage, the inside of the metal pipe may be painted with epoxy resin from the viewpoint of corrosion resistance and reducing the burden on the environment. When painting, an inexpensive filler such as silica sand may be included in the paint material to reduce the proportion of expensive epoxy resin. Patent Document 1 discloses a method for painting the inside of a metal pipe, in which silica sand is supplied at a constant supply rate by a screw feeder in parallel with the spraying of epoxy resin onto the inner wall surface of the metal pipe, and the supplied silica sand is carried by compressed air and sprayed onto the inner wall surface of the metal pipe. According to the painting method of Patent Document 1, a coating film containing a mixture of epoxy resin and silica sand can be formed inside the metal pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-131151 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the silica sand fed by the screw feeder is dropped into a horizontally extending flow path of compressed air while still in a state of free fall vertically downward motion. In this case, resistance increases when the silica sand is loaded onto the compressed air, so the silica sand may not be sufficiently loaded onto the compressed air and accumulate vertically downward in the flow path, making it difficult to spray the silica sand onto the inner surface of the metal pipe. Therefore, there is a demand for a method that can effectively spray powder such as silica sand onto an object such as the inner surface of a metal pipe.

[0005] In view of the above problems, an object of the present invention is to provide a powder discharging mechanism that can effectively spray powder onto an object. [Means for solving the problem]

[0006] A powder ejection mechanism according to one embodiment of the present invention is a powder ejection mechanism that ejects powder toward a target object using compressed gas, and includes a powder supply unit that supplies a predetermined supply amount of the powder, a powder transport unit that has a flow path for the compressed gas that extends vertically below the powder supply unit and intersects the vertical direction, and transports the powder in a transport direction along the flow path by the compressed gas flowing through the flow path, and a powder feed unit that drops the powder from the powder supply unit to the powder transport unit, the powder feed unit having a powder feed inlet provided on the powder supply unit side, a powder discharge outlet provided on the powder transport unit side, and a powder abutment portion that is provided between the powder feed inlet and the discharge outlet and against which the powder that has been dropped into the powder feed unit abuts, and the powder fed from the feed inlet is discharged from the discharge outlet, and is configured to be fed into the flow path by abutting against the powder contact portion, thereby changing the direction of motion of the powder so as to increase at least the component of motion in the transport direction.

[0007] The powder inlet may have a tubular passage connecting the inlet and the outlet, and an angle between a central axis of the passage on the powder transport section side and the transport direction may be smaller than an angle between a central axis of the passage on the powder supply section side and the transport direction, and the powder abutment portion may be formed by an inner surface of the passage located on the powder transport section side of the passage, opposite the transport direction.

[0008] The passage may be provided spaced apart from the powder supply portion.

[0009] The target object is the inner surface of a tubular body, the conveying direction is a direction along the central axis of the tubular body, and the device further includes a powder discharging section connected to the powder conveying section in the conveying direction and discharging the powder toward the target object, and the powder discharging section may discharge the powder toward the inner surface in a direction intersecting the conveying direction. Effect of the Invention

[0010] According to the powder discharging mechanism according to one embodiment of the present invention, the powder can be effectively sprayed onto a target object. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic partial cross-sectional view showing a coating device in which a powder discharging mechanism according to an embodiment of the present invention is incorporated. [Diagram 2] FIG. 2 is a schematic side view showing a powder discharging mechanism according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic enlarged cross-sectional view showing a powder discharging mechanism according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a powder discharge mechanism according to one embodiment of the present invention will be described with reference to the accompanying drawings. Note that the embodiment shown below is merely an example, and the powder discharge mechanism of the present invention is not limited to the following embodiment. Note that in this specification, "perpendicular to A" and similar expressions do not only refer to a direction completely perpendicular to A, but also refer to a direction that is approximately perpendicular to A. Also, in this specification, "parallel to B" and similar expressions do not only refer to a direction completely parallel to B, but also refer to a direction that is approximately parallel to B. Also, in this specification, "C-shape" and similar expressions do not only refer to a perfect C-shape, but also refer to a shape that visually resembles a C-shape (approximately a C-shape), such as a shape with chamfered corners of a C-shape.

[0013] [Powder Discharge Mechanism According to an Embodiment of the Invention] FIG. 1 shows a powder discharge mechanism 1 according to an embodiment of the present invention. As shown in FIG. 1, the powder discharge mechanism 1 discharges powder S1 toward a target T using compressed gas G1. Here, in this specification, "compression" refers to contracting the volume of gas by pressurizing it using a compressor or the like. Also, in this specification, "compressed gas" refers to gas whose volume has been contracted by pressurization. When the compressed gas G1 is released from the compressed state, it generates an airflow. The powder discharge mechanism 1 discharges powder S1 toward a target T using this airflow.

[0014] The compressed gas G1 used in the powder discharging mechanism 1 is not particularly limited, but is compressed air in this embodiment. However, the gas to be compressed is not particularly limited, and may be other gases such as a rare gas.

[0015] In this embodiment, the powder S1 discharged by the powder discharge mechanism 1 is a powder having a relatively heavy specific gravity (for example, specific gravity: 2.0), specifically, silica sand (for example, specific gravity: 2.5). Even if the powder S1 has a relatively heavy specific gravity, the powder discharge mechanism 1 according to this embodiment can spray the powder S1 to the target T well, as described later. Here, in this specification, "silica sand" is a powder containing quartz as a main component (for example, a quartz content of 80 wt% or more), and includes silica sand whose surface is coated with any material. Also, in this specification, "powder" is, for example, a powder having an average particle size of 5 μm to 1000 μm, preferably a powder having an average particle size of 10 μm to 500 μm, and more preferably a powder having an average particle size of 50 μm to 200 μm. When the powder S1 is silica sand, for example, silica sand No. 7 or silica sand No. 8 can be used. The powder discharging mechanism 1 according to this embodiment may also be applied to spraying other powders, such as powdered epoxy resin having a relatively light specific gravity (for example, specific gravity: 1.5).

[0016] In this embodiment, the target object T onto which the powder discharging mechanism 1 discharges the powder S1 is a pipe having an internal space extending along a central axis X1, specifically, the inner surface of the pipe, as shown in Fig. 1. The target object T is, for example, a metal pipe such as a cast iron pipe used for water supply and sewerage. However, the target object T may be the outer wall of a metal pipe, or may be selected from the surface of any other object.

[0017] The form of use of the powder discharge mechanism 1 is not particularly limited, but in this embodiment, as shown in Fig. 1, the powder discharge mechanism 1 is incorporated into a coating apparatus A for coating an object T together with a paint discharge mechanism 2 that discharges paint S2 toward the object T. The coating apparatus A can discharge silica sand as powder S1 by the powder discharge mechanism 1 while discharging powdered epoxy resin as paint S2 by the paint discharge mechanism 2. In this embodiment, the powder discharge mechanism 1 and the paint discharge mechanism 2 each include a powder pipe 1a and a paint pipe 2a that extend into the internal space of the object T along the central axis X1 of the object T (specifically, a tube). In this embodiment, the powder ejection mechanism 1 ejects powder S1 toward the target T (specifically, the inner surface of the pipe) from a powder ejection section 14 (e.g., a spray nozzle) provided at the end of the powder pipe 1a, and the paint ejection mechanism 2 ejects paint S2 toward the target T (specifically, the inner surface of the pipe) from a paint ejection section 24 (e.g., a spray nozzle) provided at the end of the paint pipe 2a.

[0018] In this embodiment, as shown in FIG. 1, the painting device A is equipped with a movable cart C (carrier), and at least a portion of the powder discharging mechanism 1 and / or the paint discharging mechanism 2 is mounted on the cart C, thereby making it movable together with the cart C (specifically, movable horizontally).

[0019] 2, the powder discharge mechanism 1 includes a powder supply unit 11 that supplies a predetermined supply amount of powder S1, a powder conveying unit 13 that conveys the powder S1 by the compressed gas G1 in a conveying direction D21 along a flow path 131 (see FIG. 3) of the compressed gas G1, and a powder input unit 12 that drops the powder S1 from the powder supply unit 11 into the powder conveying unit 13. As described above, the powder discharge mechanism 1 can further include a powder discharge unit 14 that discharges the powder S1 toward the target T. For example, of the powder discharge mechanism 1, a part of the powder supply unit 11 (a mixing tank 112 and a powder supply device 113 described later), the powder input unit 12, and the powder conveying unit 13 are mounted on the dolly C described above.

[0020] As shown in FIG. 2, the powder supplying section 11 stores the powder S1 and supplies the stored powder S1 to the powder conveying section 13 through the powder input section 12 at a predetermined supply amount. The form of the powder supplying section 11 is not particularly limited as long as the powder supplying section 11 can supply the powder S1 to the powder conveying section 13 at a predetermined supply amount. In this embodiment, the powder supplying section 11 supplies the powder S1 in a uniform state at a predetermined supply amount by using compressed gas G1. Specifically, the powder supplying section 11 includes a main tank 111 that stores the powder S1, a mixing tank 112 that mixes the powder S1 uniformly, and a powder supply device 113 that supplies the powder S1 at a predetermined supply amount. However, the powder supplying section 11 may have another structure, such as being composed of only the powder supply device 113.

[0021] The main tank 111 stores powder S1 and supplies the stored powder S1 to the mixing tank 112. In this embodiment, as shown in Fig. 2, the internal space of the main tank 111 is connected to the internal space of the mixing tank 112 by a known on-off valve 1m in an openable and closable manner. By providing the on-off valve 1m, it becomes easy to adjust the amount of powder S1 supplied to the mixing tank 112. The capacity of the main tank 111 is not particularly limited, but when the powder S1 is silica sand, for example, the main tank 111 can be selected to have a capacity capable of storing 1 t of silica sand.

[0022] When the mixing tank 112 supplies the powder S1 to the powder supplying device 113, the mixing tank 112 mixes the powder S1 so that the components and particle size of the powder S1 are uniform. By making the powder S1 uniform, the powder discharge mechanism 1 can discharge the powder S1 without uneven discharge. In this embodiment, as shown in FIG. 2, the mixing tank 112 includes a separator 112c that separates the internal space into a gas chamber 112a at the vertically lower side D11 and a stirring chamber 112b at the vertically upper side D12. For example, the separator 112c is made of a porous material and is configured to be permeable to gas but not permeable to the powder S1. In FIG. 2, the gas chamber 112a is connected to a compressed gas supply source (not shown; in this embodiment, the same compressed gas supply source as the compressed gas G1 described later) such as a known compressor that supplies compressed gas G2 (for example, compressed air) by a pipe 11a, and the compressed gas G2 supplied to the gas chamber 112a permeates the separator 112c and stirs the powder S1 supplied to the stirring chamber 112b, thereby uniformly mixing the powder S1. In this embodiment, the stirring chamber 112b is connected to the internal space of the powder supplier 113 by a known on-off valve 1n so as to be openable and closable. By providing the on-off valve 1n, it becomes easy to adjust the supply amount of the powder S1 to the powder supplier 113. The capacity of the mixing tank 112 is not particularly limited, but in this embodiment, in order to reduce the load of mixing the powder S1, it is set to a capacity smaller than the capacity of the main tank 111. When the powder S1 is silica sand, for example, the mixing tank 112 can be selected to have a capacity capable of storing 30 kg of silica sand.

[0023] As shown in FIG. 3, the powder feeder 113 supplies the powder S1 to the powder input section 12 from the supply port 113a at a predetermined supply rate. In this embodiment, the powder feeder 113 is a screw feeder that has a screw extending along the rotation axis X2 in an internal space and supplies the powder S1 to one side of the rotation axis X2 on which the supply port 113a is provided by rotating the screw around the rotation axis X2. By using the screw feeder, the supply amount of the powder S1 to the powder input section 12 can be kept constant and the supply amount can be finely adjusted. However, the form of the powder feeder 113 is not particularly limited as long as the powder S1 can be supplied at a predetermined supply rate. In this embodiment, the direction in which the rotation axis X2 extends is horizontal. However, as long as the powder S1 can be supplied to the powder input section 12 at a predetermined supply rate, the direction in which the rotation axis X2 extends is not particularly limited.

[0024] As shown in Fig. 3, the powder feed section 12 connects the powder feed section 11 and the powder conveying section 13 so that the powder S1 can be dropped from the powder feed section 11 into the powder conveying section 13. The powder feed section 12 has an inlet 12a for the powder S1 provided on the powder feed section 11 side, an outlet 12b for the powder S1 provided on the powder conveying section 13 side, and a powder contact section 12c provided between the inlet 12a and the outlet 12b and contacted by the powder S1 dropped into the powder feed section 12. The powder S1 fed from the inlet 12a is discharged from the outlet 12b after changing the direction of motion so as to increase at least the motion component in the conveying direction D21 of the flow path 131 by contacting the powder contact section 12c, thereby being fed into the flow path 131 of the powder conveying section 13. The form of powder input part 12 is not particularly limited as long as it has powder contact part 12c that increases the motion component of powder S1 in conveyance direction D21 of flow channel 131. In this embodiment, powder input part 12 has passage 121 which serves as a path for dropped powder S1. However, powder input part 12 may be configured in other forms, such as being composed only of a plate-like member with which dropped powder S1 comes into contact and increases the motion component in conveyance direction D21 of flow channel 131.

[0025] As shown in FIG. 3, the passage 121 guides the powder S1 dropped from the inlet 12a to the outlet 12b. In FIG. 3, the passage 121 is a tubular passage connecting the inlet 12a and the outlet 12b, and the powder contact portion 12c is formed by the inner surface of the passage 121 located on the opposite side of the conveying direction D21 of the flow path 131. Here, since the compressed gas G1 flows through the flow path 131, the flow path 131 becomes negative pressure, and a suction force acts on the powder supply unit 11 and the passage 121. Therefore, if the inlet 12a and the supply port 113a are connected, there is a risk that the powder S1 in the powder supply unit 11 will be excessively sucked. Therefore, in this embodiment, the powder inlet 12 is provided away from the powder supply unit 11 (specifically, the powder supplier 113). In other words, the inlet 12a of the passage 121 is provided away from the supply port 113a of the powder supply device 113. In this way, the portion between the passage 121 and the powder supply unit 11 is not connected and is open to the atmosphere, so that excessive suction of the powder S1 from the powder supply unit 11 into the flow path 131, which is under negative pressure, is suppressed. In this case, air is also sucked in together with the powder S1, so that the capacity of the powder conveying unit 13 can be fully demonstrated. In this embodiment, the inlet 12a is provided to include the supply port 113a when viewed from the vertical direction D1, for example, so as not to prevent the introduction of the powder S1 from the supply port 113a. However, the passage 121 may be connected to the powder supply unit 11 (specifically, the powder supply device 113) so that the inlet 12a of the passage 121 coincides with the supply port 113a of the powder supply unit 11. In this embodiment, the passage 121 is connected to the flow path 131 of the powder conveying unit 13 so as to reliably drop the powder S1 into the flow path 131 of the compressed gas G1. However, the passage 121 may be provided away from the flow path 131 of the powder conveying unit 13. In this case, the discharge port 12b is provided to include the inlet 13b when viewed from the vertical direction D1, for example, so as not to impede the introduction of the powder S1 from the inlet 13b.

[0026] In this embodiment, as shown in FIG. 3, the powder contact portion 12c is provided in the passage 121 so that the normal N to the inner surface of the passage 121 forms an acute angle α with respect to the vertical downward direction D11 into which the powder S1 is dropped. In this case, the powder S1 contacts the powder contact portion 12c, so that the motion component in the conveying direction D21 of the flow path 131 can be easily increased. In FIG. 3, the passage 121 is bent between the powder supply unit 11 side and the powder conveying unit 13 side. By bending the passage 121, the powder S1 that contacts the inner surface of the passage 121 is less likely to bounce back to the vertical upward direction D12, so that the efficiency of dropping the powder S1 into the passage 121 is improved. Specifically, the passage 121 is bent so that the discharge port 12b is located downstream of the feed port 12a in the conveying direction D21 of the flow path 131. 3, the passage 121 is bent so that the angle β1 between the central axis Y1 of the passage 121 on the powder conveying section 13 side and the conveying direction D21 of the flow path 131 is smaller than the angle β2 between the central axis Y2 of the passage 121 on the powder supply section 11 side and the conveying direction D21 of the flow path 131, and the powder abutment portion 12c is formed by the inner surface of the passage 121 located on the opposite side of the conveying direction D21 of the flow path 131 on the powder conveying section 13 side of the passage 121. In this case, the passage 121 on the powder conveying section 13 side where the angle β1 with the conveying direction D21 of the flow path 131 is smaller is connected to the flow path 131 of the powder conveying section 13, so that turbulence of gas is less likely to occur near the junction of the passage 121 and the flow path 131. The angle β1 between the central axis Y1 of the passage 121 on the powder conveying section 13 side and the conveying direction D21 of the flow passage 131 can be set preferably within a range of 30 degrees to 60 degrees, more preferably within a range of 35 degrees to 55 degrees, and even more preferably within a range of 40 degrees to 50 degrees. The angle β2 between the central axis Y2 of the passage 121 on the powder supplying section 11 side and the conveying direction D21 of the flow passage 131 can be set preferably within a range of 60 degrees to 90 degrees, more preferably within a range of 70 degrees to 90 degrees, and even more preferably within a range of 80 degrees to 90 degrees.

[0027] In this embodiment, the discharge port 12b is provided so as not to overlap with the inlet 12a when viewed from the vertical direction D1. In this case, the powder S1 dropped from the inlet 12a is prevented from being discharged from the discharge port 12b without contacting the powder contact portion 12c. In this embodiment, the discharge port 12b is provided so as to have a size larger than the inlet 12a. In this case, when the powder S1 is discharged from the discharge port 12b, the powder S1 does not become a high-density state near the discharge port 12b, so that the powder S1 can be easily dropped into the powder conveying portion 13.

[0028] As shown in FIG. 3, the powder conveying section 13 conveys the powder S1 supplied from the inlet 13b by the compressed gas G1. The powder conveying section 13 has a flow path 131 for the compressed gas G1 extending vertically downward D11 from the powder supplying section 11 so as to intersect with the vertical direction D1. The direction D2 in which the flow path 131 extends (in other words, the conveying direction D21 of the flow path 131) can be appropriately changed depending on the usage mode of the powder discharge mechanism 1, but in this embodiment, it is a horizontal direction. The shape of the flow path 131 is not particularly limited as long as the powder S1 can be conveyed by the compressed gas G1. In this embodiment, the flow path 131 is formed by the internal space of the powder conveying section 13 having a cylindrical shape. However, the flow path 131 may be formed by the internal space of the powder conveying section 13 having a rectangular tube shape, and may be narrowed toward the conveying direction D21 of the flow path 131, or may be widened toward the conveying direction D21 of the flow path 131. The powder conveying unit 13 conveys the powder S1 in a conveying direction D21 of the flow path 131 along the flow path 131 by compressed gas G1 flowing in the flow path 131. In Fig. 3, the flow path 131 is connected to a compressed gas supply source such as a known compressor (not shown; in this embodiment, the same compressed gas supply source as the above-mentioned compressed gas G2 (see Fig. 2)) via a pipe 13a.

[0029] As shown in FIG. 1, the powder discharge unit 14 discharges the powder S1 conveyed from the powder conveying unit 13 (see FIG. 2 and FIG. 3) toward the target T. Specifically, as shown in FIG. 2, the powder discharge unit 14 is connected to the flow path 131 of the powder conveying unit 13 on the conveying direction D21 side by the powder pipe 1a, and discharges the powder S1 conveyed from the powder conveying unit 13 toward the target T (see FIG. 1) by the compressed gas G1. The discharge direction of the powder S1 can be appropriately changed depending on the usage mode of the powder discharge mechanism 1, but in this embodiment, the powder discharge unit 14 discharges the powder S1 toward the inner surface of the tube, which is the target T, in a direction intersecting the conveying direction D21 of the flow path 131 (more specifically, a direction perpendicular to the central axis X1 of the tube, which is the target T (diameter direction of the tube)). In this case, the pressure loss of the compressed gas G1 is large because the discharge direction of the powder S1 differs from the conveying direction D21 of the flow path 131. Even in such a case, in this embodiment, by increasing the motion component of the powder S1 in the conveying direction D21 of the flow path 131, the powder S1 can easily ride on the compressed gas G1, so that the powder S1 can be sprayed onto the target T satisfactorily.

[0030] As described above, in this embodiment, as shown in Fig. 1, the powder discharge unit 14 discharges the powder S1 onto the target T in parallel with the discharge of the paint S2 onto the target T by the paint discharge unit 24. Specifically, the powder discharge unit 14 and the paint discharge unit 24 discharge the powder S1 and the paint S2, respectively, in a direction perpendicular to the central axis X1 of the tube, which is the target T (in the radial direction of the tube). In Fig. 1, the powder discharge unit 14 is connected to the powder pipe 1a so as to be disposed on the opposite side (rightward in Fig. 1) to the moving direction of the cart C (in this embodiment, one direction (horizontal direction) along the central axis X1, and leftward in Fig. 1) with respect to the paint discharge unit 24, so that the paint S2 is discharged onto the target T (specifically, onto the inner surface of the tube) before the powder S1. In this way, when the powder S1 and the paint S2 are discharged while the carriage C is moving, the paint S2 is discharged onto the object T (specifically, the inner surface of the tube) before the powder S1. In this case, the powder S1 mixes with the paint S2 before the paint S2 hardens, so that the powder S1 is easily fixed to the coating. In this embodiment, the object T (specifically, the tube) is placed on a rotating body R that rotates around the central axis X1. When the object T is a tube and the inner surface of the tube is to be painted, the powder discharge unit 14 and the paint discharge unit 24 are inserted into the internal space of the object T, and the carriage C is moved along the central axis X1 while the object T is rotated around the central axis X1 by the rotating body R. In this way, the powder S1 and the paint S2 can be discharged onto the entire inner surface of the tube, which is the object T.

[0031] [Behavior of powder in a powder discharging mechanism according to one embodiment of the present invention] Next, there will be described the behavior of the powder S1 in the above-mentioned powder discharging mechanism 1. Note that the embodiment described below is merely an example, and the behavior of the powder in the powder discharging mechanism of the present invention is not limited to the embodiment described below.

[0032] In this embodiment, as shown in FIG. 2, first, the powder S1 is supplied to the powder supplying section 11. Specifically, the powder S1 is stored in the main tank 111, and is supplied to the mixing tank 112 by opening the on-off valve 1m. In this embodiment, when the powder S1 is supplied to the mixing tank 112, the powder S1 is stirred in the stirring chamber 112b by the compressed gas G2 blown vertically upward D12 from the gas chamber 112a through the separator 112c, so that the components and particle size are homogenized. In this embodiment, the homogenized powder S1 is supplied to the powder supplying device 113 by opening the on-off valve 1n, and then, as shown in FIG. 3, the powder supplying device 113 drops a predetermined supply amount from the supply port 113a into the powder input section 12. At this time, in this embodiment, since powder input section 12 and powder supply section 11 (specifically, powder supplier 113) are disposed apart from each other, the portion between passage 121 and powder supply section 11 is not connected and is open to the atmosphere. Therefore, excessive suction of powder S1 from powder supply section 11 to flow path 131, which is in a negative pressure state, is suppressed. In this case, air is also sucked in together with powder S1, so that the capacity of powder conveying section 13 can be fully exhibited.

[0033] In this embodiment, as shown in Fig. 3, when powder S1 (see solid line arrow in Fig. 3) is dropped into powder input section 12 from inlet 12a, it falls vertically downward D11 by gravity and abuts against powder abutment section 12c formed by the inner surface of passage 121 located on the opposite side of conveying direction D21 of flow path 131. This abutment of powder S1 against powder abutment section 12c can increase the motion component of powder S1 in conveying direction D21 of flow path 131. At that time, in this embodiment, discharge port 12b is provided so as not to overlap with inlet 12a when viewed from vertical direction D1, so that powder S1 dropped from inlet 12a is prevented from being discharged from discharge port 12b without abutting against powder abutment section 12c (in other words, without changing the direction of motion).

[0034] Some of the powder S1 may bounce vertically upward D12 due to contact with the inner surface of the passage 121. However, in this embodiment, since the passage 121 is curved, the direction of the rebound of the powder S1 is limited by the curved inner surface of the passage 121, making it difficult for the powder S1 to bounce vertically upward D12. In this case, for example, the powder S1 is prevented from escaping between the inlet 12a of the passage 121 and the supply port 113a of the powder supply unit 11 (specifically, the powder supplyer 113) or from bouncing back to the powder supply unit 11 (specifically, the powder supplyer 113), so that the efficiency of dropping the powder S1 into the passage 121 is improved.

[0035] In this embodiment, as shown in FIG. 3, the powder S1 (see the solid arrow in FIG. 3) is dropped from the discharge port 12b into the powder conveying section 13 in a state where the motion component in the same conveying direction D21 as the compressed gas G1 flowing through the flow path 131 of the powder conveying section 13 is increased by contacting the powder contact section 12c. Here, in this embodiment, the discharge port 12b is provided to have a size larger than the input port 12a. In this case, when the powder S1 is discharged from the discharge port 12b, the powder S1 does not become in a high-density state near the discharge port 12b, so that the discharge performance of the discharge port 12b is improved. Therefore, in this embodiment, the powder S1 can be easily input into the powder conveying section 13 (specifically, the flow path 131 of the compressed gas G1).

[0036] 3, powder S1 (see solid line arrow in FIG. 3) is dropped into the powder conveying section 13 and introduced into the flow path 131 of the compressed gas G1. Here, in this embodiment, the angle β1 between the central axis Y1 of the passage 121 on the powder conveying section 13 side and the conveying direction D21 of the flow path 131 is smaller than the angle β2 between the central axis Y2 of the passage 121 on the powder supplying section 11 side and the conveying direction D21, and the powder abutment section 12c is formed by the inner surface of the passage 121 located on the powder conveying section 13 side of the passage 121 opposite to the conveying direction D21 of the flow path 131. In this case, by connecting the passage 121 on the powder conveying section 13 side where the angle β1 of the passage 131 with the conveying direction D21 is reduced, the merging resistance between the gas from the passage 121 and the compressed gas G1 in the passage 131 at the junction of the passage 121 and the passage 131 is reduced, so that turbulence of the compressed gas G1 is unlikely to occur at the junction of the passage 121 and the passage 131. Therefore, in this embodiment, it is possible to suppress the powder S1 from being difficult to convey due to turbulence occurring in the passage 121 or the passage 131.

[0037] 3, when the powder S1 (see the solid arrow in FIG. 3) is introduced into the flow path 131 of the compressed gas G1, the powder S1 is more likely to ride on the compressed gas G1 because the motion component in the same conveying direction D21 as the compressed gas G1 flowing through the flow path 131 increases. Therefore, in this embodiment, the powder S1 is prevented from accumulating on the vertically downward D11 side within the flow path 131, and is easily conveyed in the conveying direction D21 by the compressed gas G1.

[0038] In this embodiment, as shown in FIG. 1 (also see FIG. 3), the powder S1 is conveyed in the conveying direction D21 by the compressed gas G1, and then passes through the powder pipe 1a and is discharged from the powder discharge section 14 onto the inner surface of the tube, which is the target T. In this embodiment, the powder S1 is discharged toward the target T in a direction intersecting the conveying direction D21 (more specifically, in a direction perpendicular to the central axis X1 of the target T (diameter direction of the tube)). Therefore, the compressed gas G1 conveying the powder S1 has a large pressure loss due to the bending of the traveling direction. However, in this embodiment, even if the pressure loss of the compressed gas G1 is large, the movement component of the powder S1 in the conveying direction D21 of the flow path 131 is increased, so that the resistance when the powder S1 is placed on the compressed gas G1 is reduced, and the powder S1 can be sprayed onto the target T well.

[0039] According to the powder discharge mechanism 1 according to the present embodiment configured as described above, the powder feed section 12 is provided between the feed port 12a and the discharge port 12b, and has the powder contact section 12c with which the powder S1 fed from the feed port 12a comes into contact. The powder S1 fed into the powder feed section 12 comes into contact with the powder contact section 12c, and then the powder S1 is discharged from the discharge port 12b and fed into the flow path 131. In this way, the powder S1 is easily carried by the compressed gas G1 before being fed into the flow path 131, as the component of motion in the same conveying direction D21 as the compressed gas G1 flowing through the flow path 131 increases, and thus the powder S1 is prevented from accumulating vertically downward D11 in the flow path 131 due to gravity. Therefore, the powder S1 can be sprayed onto the target T satisfactorily.

[0040] In this embodiment, the angle β1 between the central axis Y1 of the passage 121 on the powder conveying section 13 side and the conveying direction D21 of the flow passage 131 is smaller than the angle β2 between the central axis Y2 of the passage 121 on the powder supplying section 11 side and the conveying direction D21, and the powder abutting section 12c is formed by the inner surface of the passage 121 located on the opposite side of the conveying direction D21 of the flow passage 131 on the powder conveying section 13 side of the passage 121. When the powder S1 abuts against the inner surface of the passage 121, it may bounce back to the powder supplying section 11 side, but in this embodiment, the passage 121 is bent between the powder supplying section 11 side and the powder conveying section 13 side, so that the rebound of the powder S1 is suppressed. In addition, in this embodiment, by connecting the passage 121 on the powder conveying section 13 side where the angle β1 between the passage 131 and the conveying direction D21 is reduced, turbulence of the compressed gas G1 is unlikely to occur at the junction of the passage 121 and the passage 131. Therefore, in this embodiment, it is possible to suppress the powder S1 from being difficult to convey due to turbulence occurring in the passage 121 or the passage 131.

[0041] In this embodiment, the passage 121 is provided away from the powder supply unit 11. In this case, the portion between the passage 121 and the powder supply unit 11 is open to the atmosphere, so that excessive suction of the powder S1 from the powder supply unit 11 to the flow path 131, which is in a negative pressure state, is suppressed. In this case, air is also sucked in together with the powder S1, so that the capacity of the powder conveying unit 13 can be fully exhibited.

[0042] In this embodiment, the powder discharge unit 14 discharges the powder S1 toward the inner surface of the tube, which is the target T, in a direction intersecting the conveying direction D21 of the flow path 131. In this case, since the discharge direction of the powder S1 differs from the conveying direction D21 of the flow path 131, the compressed gas G1 conveying the powder S1 is bent in its traveling direction, resulting in a large pressure loss. However, in this embodiment, even in such a case, the powder S1 comes into contact with the powder contact unit 12c to increase the motion component of the powder S1 in the conveying direction D21, thereby reducing the resistance of the powder S1 when it is placed on the compressed gas G1, thereby making it possible to spray the powder S1 onto the target T satisfactorily. [Explanation of symbols]

[0043] 1 Powder discharge mechanism 11 Powder supply section 111 Main Tank 112 Mixing Tank 112a Gas chamber 112b Mixing chamber 112c Separate body 113 Powder feeder 113a Supply port 11a Piping 12 Powder input section Aisle 121 12a Inlet 12b Outlet 12c Powder contact part 13 Powder conveying section 131 Flow Path 13a Piping 13b Loading entrance 14 Powder discharge section 1a Powder piping 1m Main tank on-off valve 1n Mixing tank on-off valve 2 Paint discharge mechanism 24 Paint discharge part 2a Paint piping A Painting equipment C Trolley D1 Vertical direction D11 Vertical downward D12 Vertically upward D2 Flow path direction D21 Transport direction G1 Compressed gas to powder supply section Compressed gas flowing through G2 passage N Normal to the powder contact area R Rotational body S1 powder S2 paint T object X1 Central axis of the object X2 Screw rotation axis Y1: Central axis of the powder conveying section of the passage Y2: Central axis of the powder supply side of the passage α Angle between the normal line of the powder contact part and the vertical downward direction D11 β1 Angle between the central axis of the powder conveying section of the passage and the conveying direction β2 Angle between the central axis of the powder supply side of the passage and the conveying direction

Claims

1. A powder discharging mechanism that uses compressed gas to discharge powder toward a target, A powder supply unit that supplies the powder at a predetermined supply amount; a powder conveying unit having a flow path for the compressed gas that extends vertically below the powder supplying unit and intersects with the vertical direction, and conveys the powder in a conveying direction along the flow path by the compressed gas flowing in the flow path; a powder input section that drops the powder from the powder supply section onto the powder transport section; Equipped with the powder input section has a powder inlet provided on the powder supply section side, a powder outlet provided on the powder transport section side, and a powder abutment section provided between the inlet and the outlet with which the powder dropped into the powder input section abuts; the powder input from the inlet abuts on the powder abutment section, thereby changing the direction of motion of the powder so as to increase at least the motion component in the transport direction, and then being discharged from the outlet, thereby being input into the flow path; The powder feed section includes a tubular passage connecting the feed port and the discharge port, The passage is provided away from the powder supply portion.

2. An angle between a central axis of the passage on the powder conveying section side and the conveying direction is smaller than an angle between a central axis of the passage on the powder supply section side and the conveying direction, The powder contact portion is formed by an inner surface of the passage located on the opposite side of the powder conveying portion side of the passage in the conveying direction.

2. The powder dispensing mechanism according to claim 1.

3. The object is an inner surface of a tube, the conveying direction is a direction along a central axis of the tube, a powder discharge unit connected to the powder conveying unit in the conveying direction and configured to discharge the powder toward the target object; The powder discharging mechanism according to claim 1 , wherein the powder discharging section discharges the powder toward the inner surface in a direction intersecting the conveying direction.

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