JP2009091096A - Powder suction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder suction device hardly causing a jam of powder, and capable of automatically evenly sucking the powder in a vessel. <P>SOLUTION: This powder suction device 1 is provided with a suction force generation means 3, a powder suction pipe 4 connected to the suction force generation means 3, and a rotation drive means 5 rotating the powder suction pipe 4 around one rotational center line A<SB>R</SB>. The powder suction pipe 4 is provided with a powder suction pipe body 17 forming a powder passage 16 having a base-end-side discharge opening 22 connected to the suction force generation means 3, and a powder suction opening 21 being a tip-side powder suction opening 21 sucking the powder, and arranged radially separately from the rotational center line A<SB>R</SB>, and a suction tube 19 forming an air passage 18 having a base end-side intake 23 and tip-side air supply openings 24 opened into the powder passage 16 in the vicinity of the powder suction opening 21. The powder suction pipe 4 sucks the powder from the powder suction opening 21 and sucks air from the intake 23 while rotating. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a powder suction device used for sucking powder.

  2. Description of the Related Art A powder suction device that sucks powder stored in a container and automatically supplies it to another device that consumes the powder is used, for example, in the manufacture of heat exchangers. The powder in this case is a powder flux mainly composed of, for example, aluminum fluoride used when brazing aluminum tube members of a heat exchanger, etc., and is supplied to the flux coating process, where the brazing target member It is applied to a tube member or the like. Conventionally, a powder suction device using a suction nozzle and a suction pump has been used to automatically supply a powder flux to a flux application process. The suction nozzle of this apparatus is provided with a powder suction port substantially aligned with the longitudinal axis of the pipe line at its tip, and while being driven to rotate about the longitudinal axis, a suction pump communicated with the suction nozzle. The powder flux is sucked from the powder suction port and supplied to the flux application process.

  Usually, the powder flux has a small particle size and relatively high adhesion and agglomeration, so clogging may occur particularly near the powder suction port of the suction nozzle. When clogging occurs in this way, automatic and stable supply of flux to the flux application process is hindered, as well as labor for eliminating the clogging. Another problem with the conventional apparatus is that the powder in the container cannot be uniformly sucked and as a result, the remaining amount of flux is large.

  In order to prevent the occurrence of clogging of powder, Patent Document 1 discloses a powder suction nozzle that injects compressed air into powder in a powder suction port. However, this powder suction nozzle is considered to have a problem from the viewpoint of requiring a compressed air source and automatically and uniformly sucking the powder in the container.

JP 2000-289853 A

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a powder suction device capable of automatically and uniformly sucking powder in a container without causing powder clogging. There is to do.

In order to solve the above-mentioned problem, the invention described in claim 1 includes a suction force generating means (3), a powder suction pipe (4) connected to the suction force generating means (3), and a powder. A powder suction device comprising: a rotation driving means (5) for rotating the suction pipe (4) about one rotation center line (A _R ), wherein the powder suction pipe (4) generates suction force; The base end side discharge port (22) connected to the means (3) and the front end side powder suction port (21) for sucking powder are separated from the rotation center line (A _R ) in the radial direction. A powder suction pipe body (17) that forms a powder passage (16) having a powder suction port (21) provided, and a vicinity of the proximal suction port (23) and the powder suction port (21) And an intake pipe (19) that forms an air passage (18) having an air supply port (24) on the front end side that opens into the powder passage (16). While, and intake port while sucking the powder from the powder inlet (21) from (23), characterized in that sucking air.

  As a result, the air from the air supply port (24) joins the powder flow sucked from the powder suction port (21), so that the flow of the powder having a high air content and therefore hardly clogging is prevented. Obtainable. Further, the powder suction tube is rotated to promote the flow of the powder, and the direction and position of the powder suction port (21) that is radially spaced from the center of rotation also changes, so that the powder is not evenly distributed. Efficient suction is possible.

  A second aspect of the present invention is the lifting bracket according to the first aspect, wherein the suction force generating means (3), the powder suction pipe (4) and the rotation driving means (5) are fixedly supported and moved up and down. (6) and a suspension support means (7) for suspensionly supporting the lifting bracket (6), and the powder suction pipe (4) rotates while the powder suction pipe (4) descends based on gravity. A powder suction device for sucking, wherein the suspension support means (7) includes a fixed frame (10) for guiding the elevating bracket (6) as an upright fixed frame (10), a weight (11), A pulley (12) fixed to a fixed frame (10), one end connected to a weight (11), the other end connected to a lifting bracket (6), and an intermediate portion wound around the pulley (12) (13), and the weight (11) It is characterized in that acting in a direction to reduce the lowering speed of the tube (4). Thereby, since the powder suction pipe (4) rotates while descending, it becomes possible to suck the powder more evenly and efficiently. Moreover, no power is required for lowering, and the lowering speed can be easily obtained by adjusting the weight of the weight (11).

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the powder passage (16) of the powder suction pipe body (17) of the powder suction pipe (4) is provided with a powder suction port ( 21) and an upstream passage portion (28) in which an air supply port (24) is opened, and a downstream passage portion (27) having a discharge port (22). ) Having a longitudinal axis (A ₁ ) parallel to the rotation center line (A _R ) and forming a downstream-side passage portion (27), a linear first pipe portion (25), and a first pipe portion ( 25) and a second pipe portion (26) extending perpendicularly to the longitudinal axis (A ₁ ) to form the upstream passage portion (28), and the powder suction port (21) is a rotation center line the second pipe portion on the side preceding the rotation about the (a _R) in the peripheral wall (26), in the direction of the second pipe section longitudinal axis (26) (a ₂₎ It is characterized by being Ku formed.

  As a result, the powder suction port (21) formed long along the second pipe portion (26) is more efficient due to its horizontally long shape when, for example, the powder accumulated in the cylindrical tank is sucked while rotating. Allows for efficient suction. Moreover, the stirring effect of the powder by the 2nd pipe part (26) extended in the radial direction of rotation is also acquired.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the air passage (18) of the intake pipe (19) has a plurality of air supply ports (opened into the upstream passage portion (28)). 24). This makes it possible to disperse and arrange the plurality of air supply ports (24) at optimal positions according to the shape and size of the powder suction port (21).

  According to a fifth aspect of the invention, in the invention of the third or fourth aspect, when the powder suction pipe (4) is rotated, the powder suction port (21) is advanced in the powder in the forward direction of travel. In addition, the powder suction pipe (4) further includes an excavation barrier member (33) formed so as to prevent the powder from moving outward in the radial direction. This makes it easier for the powder blocked by the digging barrier member (33) to be guided to the powder suction port (21), and the breaking and stirring action on the powder in front of the powder suction port (21). Is obtained.

  The invention according to claim 6 is the invention according to claim 5, wherein the excavation barrier member (33) is formed as a belt-like member curved inward in the radial direction of rotation, and the end portion of the second pipe portion (26). The base end portion of the belt-like member is fixed to the tip end portion (33a), which is a free end, and is tapered. Thereby, while the resistance at the time of advancing of the digging barrier member (33) reduces, the crushing effect | action with respect to powder is heightened.

The invention according to claim 7 is the invention according to claims 3 to 6, wherein one end is fixed to the first pipe portion (25), and the longitudinal axis (A ₁ ) of the first pipe portion (25). It further comprises at least one stirring member (34) having intersecting axes (A ₃ ). Thereby, the stirring effect with respect to powder is further improved.

  The invention according to an eighth aspect is characterized in that, in the invention according to the seventh aspect, the stirring member (34) is at least partially flexible. Thereby, for example, even when the entrance of a cylindrical tank storing powder is narrowed, the stirring member (34) can be bent and allowed to pass through the tank entrance. A stirring member (34) having a large rotating circle outer diameter can be used.

  In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means as described in the Example mentioned later.

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of a powder suction device 1 according to an embodiment of the present invention and a cylindrical tank 2 storing powder (not shown). In this embodiment, the sucked powder is a powder flux mainly composed of aluminum fluoride for brazing an aluminum material.

A powder suction device 1 in FIG. 1 includes, for example, a venturi pump 3 that is a suction force generating means 3 that generates a suction force, a powder suction pipe 4 in which only the upper base end side is shown in FIG. around a rotation center line a _R extending in the rotational drive means 5 for rotating the direction of arrow R in FIG powder suction pipe 4, fixedly supporting the venturi pump 3 and the powder suction pipe 4 and the rotary drive means 5 A lifting bracket 6 that moves up and down, a suspension support means 7 that supports the lifting bracket 6, a rotary joint 8 interposed between the powder suction pipe 4 and the venturi pump 3, and a tank stand 9. And the powder suction tube 4 is configured to descend based on gravity while rotating. FIG. 1 shows a state in which the elevating bracket 6 is lowered to its lower limit position. A powder suction port 21 (not shown) on the distal end side of the powder suction pipe 4 is immersed in the powder flux and just before the bottom surface of the tank 2. positioned. Further, the powder flux sucked from the tank 2 passes through the discharge pipe 48 of the venturi pump 3 and is fed to another device (not shown) such as a brazing device.

Next, each component of the powder suction apparatus 1 of the present embodiment will be described in detail below.
First, the suspension support means 7 includes a fixed frame 10 erected to guide the lifting bracket 6 up and down, a weight 11, a pulley 12 fixed to the fixed frame 10, one end connected to the weight 11 and the other end. A wire 13 connected to the lifting bracket 6 and having an intermediate portion wound around a pulley 12 is provided so that the powder suction tube 4 slowly descends in the powder flux based on gravity. A downward force due to its own weight and the weight of the powder suction tube 4 and the rotation driving means 5 and the venturi pump 3 acts on the lifting bracket 6, and the upward resistance force that the powder suction tube 4 receives from the powder flux The force based on the weight of the weight 11 acts upward. Accordingly, by increasing or decreasing the weight of the weight 11, it is possible to bring the lowering speed of the lifting bracket 6 closer to the optimum value. Further, in the suspension support means 7 in this embodiment, two horizontal handles 14 are provided on the weight 11 so that a person pushes down the weight 11 when the lifting bracket 6 is raised. A lock device (not shown) is provided to lock the depressed weight 11 at its lower limit position. In addition, when the powder suction tube 4 is lowered, the weight 11 is stopped at a predetermined upper limit position so that the lowering is stopped just before the tip of the powder suction tube 4 contacts the bottom surface of the tank 2. 15 is fixed to the fixed frame 10. Further, when the weight 11 comes into contact with the stopper 15, in order to stop the operation of the rotation driving means 5 and the venturi pump 3, a microswitch actuator (not shown) in which the weight 11 comes in contact with the stopper 15 is also provided in the fixed frame 10. It has been.

FIG. 2 is a front view of a single powder suction tube 4 according to an embodiment of the present invention. The powder suction pipe 4 includes a powder suction pipe body 17 that forms a powder passage 16 and an intake pipe 19 that forms an air passage 18. The powder passage 16 in the powder suction pipe main body 17 has a powder suction port 21 on the front end side which is immersed in the accumulation of the powder flux in order to suck the powder flux (not shown), and is shown in FIG. And a discharge port 22 on the base end side connected to the venturi pump 3 through a rotary joint 8 that is not provided. Powder inlet 21 is provided to be radially spaced from the rotational center line A _R. The air passage 18 in the intake pipe 19 has a proximal-side intake port 23 and a distal-side air supply port 24, and the air supply port 24 is branched at the distal-end side in this embodiment. Two air supply ports 24 are provided. The air inlet 23 is provided so as to be spaced apart from the powder inlet 21 so as to be open to the atmosphere even when the powder inlet 21 is sucking the powder flux.

In the powder suction tube 4 shown in FIG. 2, the powder suction tube main body 17 includes a linear first pipe member 25 having a longitudinal axis A ₁ coinciding with the rotation center line _AR, and the first pipe member. The second pipe member 26 extends perpendicularly to the longitudinal axis A ₁ of 25 and has one end welded to the first pipe member 25. The powder passage 16 includes an upstream passage portion 28 formed by the second pipe member 26 and having the powder suction port 21, and a downstream passage portion 27 formed by the first pipe member 25 and having the discharge port 22. It is configured. FIG. 3 is a cross-sectional view taken along the line YY of FIG. 2, that is, a cross-sectional view of the second pipe member 26 at the air supply port 24, and the arrow C in the drawing indicates the powder sucked from the powder suction port 21. The arrow D represents the flow of air flowing toward the air supply port 24. Powder inlet 21, have been formed in the peripheral wall of the second pipe member as long oval in the direction of the longitudinal axis A ₂ extending horizontally in the 26 second pipe member 26, as can be seen from FIGS. 2 and 3 When the powder suction pipe 4 is rotated in the rotation direction indicated by the arrow R, the powder suction pipe 4 is opened in the peripheral wall of the second pipe member 26 on the preceding side.

  On the peripheral wall of the first pipe member 25 at the joint between the first pipe member 25 and the second pipe member 26, there is a peripheral wall through hole (not shown) so that the upstream-side passage portion 28 and the downstream-side passage portion 27 communicate with each other. Opened. Further, a flange-shaped disk 29 is provided at the tip of the first pipe member 25 for the purpose of closing the tip, reinforcing the second pipe, and increasing resistance from the powder flux when descending. Are welded. By the way, the powder suction pipe body 17 in the embodiment of FIG. 2 is formed by welding two separate first pipe members 25 and second pipe members 26. In particular, when the pipe diameter is relatively thin. Alternatively, it is possible to form an equivalent to the powder suction pipe body 17 shown in FIG. 2 by bending one pipe member in an L shape near the tip.

  In the present embodiment, the intake pipe 19 is composed of a straight pipe part 31 fixed to the first pipe member 25 and a branch pipe part 32 on the front end side. The distal end of the branch pipe section 32 is joined to the upper peripheral wall of the second pipe member 26 so that the two air supply ports 24 open into the upstream passage section 28. In the present invention, the number of air supply ports 24 is of course not limited to two, and any other number is possible. In the present embodiment, the intake air amount is constant, but a flow rate adjusting means such as a throttle valve can be added to the intake pipe 19 in order to adjust the intake air amount.

  Furthermore, the powder suction pipe 4 in the present embodiment is provided with a digging barrier member 33 which is curved in a belt shape with one end fixed to the outer end portion of the second pipe member 26 and has a tapered tip. The digging barrier member 33 has a width substantially equal to the outer diameter of the second pipe member 26 and closes the outer end portion of the second pipe member 26, and from the fixed base end portion, powder suction. The tube 4 is curved and extends inward in the radial direction of rotation. Moreover, the front-end | tip part 33a which is a free end of the digging barrier member 33 is tapered by reducing the width of the member as shown in FIG. By the way, when the powder suction tube 4 is rotated, a part of the powder flux in the forward direction of the powder suction port 21 is not sucked into the powder suction port 21 and tends to flow outward in the radial direction. However, by providing the excavation barrier member 33, the movement of the powder flux to the outside in the radial direction is obstructed, and as a result, the powder flux is easily guided to the powder suction port 21. Further, since the digging barrier member 33 has the tapered tip portion 33a, for example, even in the case of a flux that has been agglomerated and solidified, the digging barrier member 33 can proceed while collapsing it. It is preferable to form the digging barrier member 33 from a band-shaped member curved inward as shown in FIG. 2 because the resistance is reduced. However, the digging barrier member 33 is linear from the other tangential direction to the radially inner side. An inclined shape is also possible.

Further, as shown in FIG. 2, the powder suction tube 4 has a vertical axis A ₃ extending in a direction perpendicular to the vertical axis A ₁ of the first pipe member 25 in order to agitate the powder flux by its rotation. Five members 34 are provided. The stirring member 34 in this embodiment includes a mounting bar portion 35 that is welded and fixed to the first pipe member 25, and a stirring bar portion 37 that is fitted to the mounting bar portion 35 and is screwed with two bolts 36. It is composed of The stirring rod portion 37 includes a connecting portion 38 formed of a pipe material connected to the mounting rod portion 35, and a flexible portion 39 on the distal end side fixed to the connecting portion 38, and the flexible portion Reference numeral 39 denotes a coil spring. Since the flexible portion 39 is provided, even when the tank 2 in which the inlet portion of the tank 2 storing the flux is narrowed, the flexible portion 39 is flexible when the powder suction tube 4 is inserted into the tank 2. it is possible to deflect the sexual portion 39, it is possible to set outside than the inner diameter of the inlet portion position of the tank 2 from the rotation center line a _R of the order of the stirring member 34 tip. Moreover, although the normal flux is put in the tank 2 in a state of being in a plastic bag (not shown), since the stirring member 34 has flexibility, the tip thereof is difficult to be caught on the plastic bag. can get.

In the present embodiment, the flexible portion 39 of the stirring member 34 is formed of a coil spring, but may be formed of a flexible synthetic resin tube material instead of the coil spring. Further, the number of stirring members 34 is not limited to five, and any other natural number is possible. Furthermore, the longitudinal axis A ₃ of the stirring member 34, in this embodiment intended but extends perpendicularly to the longitudinal axis A ₁ of the first pipe member 25, in the present invention which is thus vertically limited without and can be of any angle that intersects the longitudinal axis a ₁ of the first pipe member 25. In FIG. 2, the five stirring members 34 are arranged in a line, but may not be arranged in this way.

Returning to FIG. 1, the rotation driving means 5 will be described. The rotation driving means 5 in this embodiment includes a motor 41 fixed to the lifting bracket 6 and a first pulley 42 coupled to the tip of the output shaft of the motor 41. And a second pulley 43 coupled to the upper end of the powder suction tube 4 and a transmission belt 44 wound around the first and second pulleys 42 and 43. Accordingly, when the motor 41 is started powder suction pipe 4 is driven to rotate around a rotation center line A _R in the direction of arrow R.

  The venturi pump 3 includes a pump body 45, a suction short pipe 46, an air pipe 47, and a discharge pipe 48. The suction short pipe 46 is connected to one end side (not shown) of the rotary joint 8 and is attached to the lifting bracket 6. It is fixed.

Next, the connection between the powder suction pipe 4 and the venturi pump 3 will be described. The upper end of the powder suction pipe 4 is fixed to the other end (not shown) of the rotary joint 8, and the rotary joint 8 is connected to the lifting bracket. by being fixed to 6, but in the vertical and horizontal directions are immovable and are rotatably supported by the lift bracket 6 around the rotation center line a _R. On the other hand, the venturi pump 3 has its suction short pipe 46 fixed to the lifting bracket 6 and connected to one end of the rotary joint 8, so that fluid communication is not made with the discharge port 22 at the upper end of the powder suction pipe 4. However, the rotational movement of the powder suction pipe 4 is not transmitted to the suction short pipe 46 of the venturi pump.

Next, the operation of the powder suction device 1 according to the present embodiment will be described below including the procedure for using the device.
First, in order to set the powder suction pipe 4 at a predetermined upper position, the handle 14 of the weight 11 is pushed down by human power to lock the weight 11 at its lower limit position. Next, place the tank 2 the powder flux stored predetermined position, i.e. in the center as the rotation center line A _R and matches the position of the tank 2. Next, the venturi pump 3 and the motor 41 of the rotational drive means 5 are turned on to start them. Next, the weight 11 is unlocked and the powder suction tube 4 is lowered by gravity. Then, the powder suction pipe 4 is gradually lowered while rotating the rotation center line A _R around the powder inlet 21 is retracted to aspirate the powder flux in the powder flux. However, since the intake port 23 of the intake pipe 19 is provided in the upper part and is open to the atmosphere, the powder suction pipe 4 simultaneously draws air from the intake port 23 while sucking the powder flux from the powder suction port 21. The air is sucked and joined to the flow of the powder flux at the air supply port 24. As a result, the powder flux containing a relatively large amount of air passes through the powder passage 16 and consumes the flux of the brazing device or the like from the discharge port 22 through the suction short pipe 46 and the discharge pipe 48 of the venturi pump 3. Sent to the device. When the weight 11 comes into contact with the stopper 15, the lowering of the powder suction pipe 4 stops and at the same time the motor 41 and the venturi pump 3 stop.

  In the powder suction device 1 of the present embodiment, as described above, air is sucked together with the powder flux through the intake pipe 19, so that the powder flux has a large air content and is therefore difficult to be clogged, and thus the powder passage 16 and the venturi pump. It is possible to flow through each of the three pipelines. Further, the powder suction pipe 4 is rotated while descending, whereby the flow of the powder flux is promoted and the position of the powder suction port 21 extending in the radial direction is changed. It becomes possible to suck. This effect is promoted by the provision of the stirring member 34 and the second pipe member 26 extending horizontally. Furthermore, by providing the excavation barrier member 33, the breakage of the powder flux and the induction of the flux to the powder suction port 21 are promoted.

  The powder suction device 1 according to the above-described embodiment includes a lifting bracket 6 and a suspension support means 7 in addition to the suction force generation means 3, the powder suction pipe 4, and the rotation drive means 5, and rotates and descends the powder suction. Although the tube 4 is configured to suck the powder flux, in the present invention, a powder suction device including a powder suction tube that does not descend is also possible. Such a device can be easily realized by fixing the lifting bracket 6 of the powder suction device of the above-described embodiment so that it cannot move.

1 is a schematic perspective view of a powder suction device according to an embodiment of the present invention. It is a front view of the powder suction pipe | tube of the said powder suction apparatus. It is YY sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Venturi pump 4 Powder suction pipe 5 Rotation drive means 6 Lifting bracket 7 Suspension support means 11 Weight 16 Powder passage 17 Powder suction pipe main body 18 Air passage 19 Intake pipe 21 Powder intake port 22 Exhaust port 23 Intake port 24 Air Supply port 33 Barrier member 34 Stirring member

Claims (8)

Suction force generating means (3);
A powder suction tube (4) connected to the suction force generating means (3);
A powder suction device comprising: a rotary drive means (5) for rotating the powder suction pipe (4) around one rotation center line ( _AR );
The powder suction pipe (4) has a discharge port (22) on the proximal end connected to the suction force generating means (3) and a powder suction port (21) on the distal end side for sucking powder. A powder suction pipe body (17) forming a powder passage (16) having a powder suction port (21) provided radially away from the rotation center line (A _R ); An intake pipe (18) that forms an air passage (18) having an air supply port (24) on the distal end side that opens into the powder passage (16) in the vicinity of the intake port (23) and the powder suction port (21). 19) and
The powder suction device, wherein the powder suction pipe (4) sucks powder from the powder suction port (21) and sucks air from the suction port (23) while rotating. A lifting bracket (6) that moves up and down while fixing and supporting the suction force generating means (3), the powder suction pipe (4), and the rotation driving means (5), and the lifting bracket (6) is suspended and supported. The powder suction apparatus according to claim 1, further comprising a suspension support means (7), wherein the powder suction pipe (4) sucks powder and air while descending based on gravity while rotating. There,
The suspension support means (7) is fixed to the fixed frame (10) that guides the elevating bracket (6) as an upright fixed frame (10), a weight (11), and the fixed frame (10). A pulley (12) having one end connected to the weight (11), the other end connected to the elevating bracket (6), and an intermediate portion wound around the pulley (12) , And
A powder suction device, wherein the weight of the weight (11) acts in a direction to decrease the descending speed of the powder suction tube (4). The powder passage (16) of the powder suction tube body (17) of the powder suction tube (4) has the powder suction port (21) and the air supply port (24) is opened. An upstream passage portion (28) and a downstream passage portion (27) having the discharge port (22),
The powder suction tube main body (17) has a longitudinal _first line portion (A ₁ ) parallel to the rotation center line (A _R ) and forms the downstream passage portion (27). (25) and a second pipe part (26) extending perpendicularly to the longitudinal axis (A ₁ ) of the first pipe part (25) to form the upstream passage part (28). ,
The powder suction port (21) is connected to the peripheral wall of the second pipe portion (26) on the side preceding the rotation with respect to the rotation center line (A _R ) on the longitudinal axis (A The powder suction device according to claim 1 or 2, wherein the powder suction device is long in the direction of ₂ ).   The air passage (18) of the intake pipe (19) has a plurality of air supply ports (24) that open into the upstream passage portion (28). The powder suction apparatus according to claim 1.   When the powder suction pipe (4) is rotated, the powder suction port (21) is formed so as to dig in the powder forward in the traveling direction and prevent the powder from moving radially outward. 5. A powder suction device according to claim 3 or 4, characterized in that the powder suction pipe (4) further comprises a digging barrier member (33).   The digging barrier member (33) is formed as a belt-like member curved inward in the radial direction of the rotation, and a base end portion of the belt-like member is fixed to an end portion of the second pipe portion (26). 6. Powder suction device according to claim 5, characterized in that a tip (33a) is tapered. At least one stirring member (34) having one end fixed to the first pipe portion (25) and having an axis (A ₃ ) intersecting the longitudinal axis (A ₁ ) of the first pipe portion (25). The powder suction device according to any one of claims 3 to 6, further comprising:   8. A powder suction device according to claim 7, characterized in that the stirring member (34) is at least partially flexible.

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