JP2007210022A - Powder charging device and powder charging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder charging device capable of uniformly charging a powder. <P>SOLUTION: The powder charging device is provided with a powder storing basin 17, which keeps upper and lower face open each at least in a part, and powder charging vessels 30, which are close to the bottom surface of the powder storing basin 17 and movable in a horizontal direction. When a powder charging vessel 30 passes through the opened area of the lower face of the powder storing basin 17, the powder stored in the powder storing basin 17 is charged into the powder charging vessel 30 by a free fall. There are provided a means 22 for jetting a gas to the powder in the powder storing basin 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus and method for filling a container with powder.

  In the case where powder is filled in a mold and the powder is compression-molded by a punch, in order to increase the dimensional accuracy of the compression-molded product or to make the density of the compression-molded product uniform, It is necessary to uniformly fill the powder. The filling of the powder into the mold proceeds by replacing the air present in the mold with the powder to be filled. Therefore, when air and powder are not smoothly replaced in the mold, it may take time to fill the powder. In addition, depending on the type of the molded product, the powder may contain a liquid component, and as a result, the fluidity of the powder may be reduced, making it difficult to uniformly fill the mold. In some cases, a so-called bridge phenomenon may occur in which the powder having decreased fluidity closes the opening of the mold.

  For the purpose of uniformly filling the mold with powder, move the lower punch installed in the mold downward while the upper opening of the mold is closed with a feeder, There has been proposed a method in which powder is sucked and filled into a cavity while preventing air from entering (see Patent Document 1). According to this method, since the exchange of powder and air does not occur, the powder can be filled quickly and uniformly.

  However, in this method, it is not easy to efficiently perform filling because an operation for closing the upper opening of the mold with a feeder and a suction operation are separately required each time the powder is filled in the mold. Moreover, since it is necessary to make an apparatus an airtight structure so that air may not enter from the outside, the request | requirement with respect to the dimensional accuracy of an apparatus will become high.

JP 2002-53901 A

  Accordingly, an object of the present invention is to provide an apparatus and a method capable of filling powder more efficiently and uniformly than the prior art described above.

The present invention comprises a powder storage container in which at least a part of an upper surface and a lower surface is open, and a powder filling container that is movable in the horizontal direction in proximity to the lower surface of the storage container, and the filling container is the storage container. In the powder filling device in which the powder stored in the storage tank is filled into the filling container by free fall when passing through the open area of the lower surface of
The present invention provides a powder filling apparatus provided with means for injecting a gas toward a powder in a powder storage basket.

In the present invention, the powder filling container is moved in the horizontal direction so as to be close to the lower surface of the powder storage tank in which at least a part of the upper surface and the lower surface is open, and the filling container passes through the open area of the lower surface of the storage tank. In the powder filling method of filling the filling container by free fall of the powder stored in the storage tank,
The present invention provides a powder filling method in which a gas is injected toward a powder in a powder reservoir and filling is performed in a state where the powder is flowed.

Furthermore, the present invention provides a powder storage trough having at least a part of its upper and lower surfaces opened, and a rotary disc provided with a mortar hole penetrating in the thickness direction and movable in the horizontal direction close to the lower surface of the storage trough And an upper arm and a lower arm that are respectively slidable up and down on the rotating disk and are movable in the horizontal direction in synchronization with the movement of the rotating disk, and the tip of the lower arm is in the mortar In a powder compression molding machine in which the powder formed in the storage rod is filled into the die by free fall when the inserted and formed die passes through the open area of the lower surface of the storage basket. ,
The present invention provides a powder compression molding machine provided with means for injecting a gas toward a powder in a powder storage basket.

  According to the present invention, when the powder is filled, since the powder is in a fluid state, it can be filled uniformly. Further, even when the filling speed is increased, or even when a powder having low fluidity is targeted, uniform filling is possible.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 schematically shows a perspective view of a rotary powder compression molding machine as one embodiment of the present invention. In the molding machine 10 shown in FIG. 1, a standing shaft 12 is disposed on the center portion of a pedestal 11. The upright shaft 12 is pivotally supported by a bearing (not shown) attached to the base 11. A rotational driving force of a motor (not shown) is transmitted to the vertical shaft 12 via a belt (not shown), and rotates in a direction indicated by an arrow in the figure. A circular rotating disk 13 that is a disk-shaped body having a predetermined thickness is fixed to the vertical shaft 12. The turntable 13 is attached to the vertical shaft 12 so that the center thereof coincides with the axis of the vertical shaft 12. The rotary disk 13 is configured to rotate in the same direction as the vertical shaft 12 in a horizontal plane of the rotary disk 13 while being fixed to the vertical shaft 12.

  The turntable 13 is provided with a plurality of mortar holes 14. The mortar hole 14 penetrates the turntable 13 in the thickness direction. The mortar hole 14 is located concentrically with the circumference of the turntable and is arranged at a constant interval on the circumference of a circle having a smaller radius than the turntable.

  On the top of the turntable 13, the same number of upper punches 15 as the number of mortar holes 14 are installed. On the other hand, the same number of lower punches 16 as the number of mortar holes 14 are similarly installed in the lower part of the rotating disk 13. The upper punch 15 and the lower punch 16 have the same cross-sectional shape as that of the mortar hole 14, and can penetrate into the mortar hole 14 without any gap. The upper punch 15 and the lower punch 16 are installed at positions where their axial centers coincide with the center of the mortar hole 14.

  The upper rod 15 and the lower rod 16 can be rotated in the same direction as the rotating disk 13 in synchronization with the rotating movement of the rotating disk 13. Therefore, even if the turntable 13 rotates, the positional relationship between the axes of the upper punch 15 and the lower punch 16 and the center of the mortar hole 14 does not change. At the same time, the upper rod 15 and the lower rod 16 are slidable in the vertical direction along the axis. Thereby, the upper punch 15 and the lower punch 16 can be inserted into the mortar hole 14. The sliding of the upper rod 15 and the lower rod 16 can be performed by a known means such as a hydraulic device or a lifting cam.

  The molding machine 10 is further provided with an open feed shoe 17 as a powder reservoir. The feed shoe 17 is located on the rotary disk 13 described above. Unlike the turntable 13, the feed shoe 17 is fixed. The turntable 13 moves in the horizontal direction in proximity to the lower surface of the feed shoe 17. The feed shoe 17 includes a wall portion 18 that is orthogonal to the horizontal plane of the rotating disk 13. At least a part of the upper surface and the lower surface of the wall 18 is open. The wall portion 18 has a closed shape in order to prevent leakage of the raw material powder.

  A powder supply device 19 is installed on the feed shoe 17. The raw material powder 20 is supplied continuously or intermittently from the powder supply device 19 into the feed shoe 17.

  As viewed from the feed shoe 17, a sliding plate 21 is installed on the downstream side in the rotation direction of the rotating disk 13. The slide plate 21 is in a fixed state, and is installed so that the lower surface thereof is in contact with the upper surface of the turntable 13. The upper surface of the rotary disk 13 slides in contact with the lower surface of the scraping plate 21, thereby filling the mortar hole 14 and removing the raw material powder overflowing there.

  The production of a compression molded body using the molding machine 10 having the above configuration will be described. At the position A in FIG. 1, the tip of the lower punch 16 is inserted into the mortar hole 14 by a lifting mechanism (not shown). . Thereby, a die as a powder filling container is formed by the die hole 14 and the upper end surface of the lower punch 16. On the other hand, the upper collar 15 is raised and retracted by an elevating mechanism (not shown) so as not to collide with the feed shoe 17.

  When the die passes through the open area on the lower surface of the feed shoe 17 by the rotation of the turntable 13, the raw material powder supplied from the powder supply device 19 into the feed shoe 17 is filled into the die by free fall. The filling of the raw material powder is finished when the die exceeds the opening area of the lower surface of the feed shoe 17. In the present embodiment, the entire area of the lower surface of the feed shoe 17 is open.

While the mortar at the position A reaches the position B by the rotation of the turntable 13, the lower punch 16 is slightly lifted by a lifting mechanism (not shown). A part of the raw material powder filled in the mortar overflows from the mortar as the lower punch 16 rises. The overflowing raw material powder is removed by a sliding plate 21 installed at a position B in FIG. As a result, the inside of the die is fully filled with the raw material powder.

  When the rotation of the turntable 13 further proceeds, the lower punch 16 starts to descend while keeping the position of the lower punch 16, and the tip of the upper punch 15 is inserted into the die. The raw material powder filled in the die is made to slide between the lower end surface of the upper punch 15 and the lower punch 16 by sliding both punches in the directions close to each other with the tips of the both tips inserted into the die. Compressed between the upper end surfaces of The raw material powder is preferably compressed in two stages: pre-compression performed at a relatively low pressure and main compression performed at a pressure higher than the pre-compression. Thereby, a compression-molded body having a uniform density can be obtained. The rotating disk 13 continues to rotate during this compression.

  When a compact is obtained by applying a compression force to the raw material powder for a predetermined time, the upper platen 15 is lifted and taken out from the die while continuing to rotate the rotating disk 13, and is retracted upward. At the same time or a little later, the lower eyelid 16 is also raised. The lower collar 16 rises to a position where the upper end surface thereof is flush with the upper surface of the turntable 13. As a result, at the position indicated by C in FIG. 1, the molded body 21 compression-molded in the die is taken out from the die. Thereafter, the lower arm 16 descends and returns to the position where the mortar is formed together with the mortar hole 14.

  Thus, in the molding machine 10 of the present embodiment, as shown in FIG. 2, a gas injection nozzle 22 is attached to the wall portion 18 of the feed shoe 17. The tip of the nozzle 22 protrudes into the feed shoe 17, and gas can be injected toward the raw material powder 20 supplied into the feed shoe 17. The raw material powder 20 is vigorously agitated by the gas injection and becomes fluidized in the feed shoe 17. As a result, the inflow of the raw material powder into the die 30 proceeds smoothly, and the raw material powder 20 can be uniformly filled in the die 30. Further, even when the raw material powder 20 contains a liquid component and the fluidity is lowered, or even when the rotation speed of the rotating disk 30 is high, the raw material powder 20 can be uniformly filled in the die 30. Become.

  In order to bring the raw material powder 20 into a desired flow state, for example, (b) gas type, (b) timing of gas injection, (c) injection time, (d) injection pressure, (e) injection amount, etc. What is necessary is just to adjust suitably.

  Any kind of gas may be used as long as the raw material powder 20 can be fluidized. It is simple and economical to use air as the gas. However, it is also possible to use other gases, for example inert gases such as nitrogen. Whatever gas is used, the moisture content in the gas is preferably as low as possible.

  The gas injection time and the injection pressure are appropriately selected depending on the specific gravity and shape of the raw material powder.

  As shown in FIG. 2, the gas injection nozzle 22 is installed on the most upstream side of the wall portion 18 of the feed shoe 17 with respect to the rotation direction of the rotating disk 13. Further, with respect to the height direction of the wall portion 18, it is preferable that the injection nozzle 22 be installed in a lower area of the wall portion 18. By installing the injection nozzle 22 at such a position, the raw material powder 20 can be efficiently fluidized. Furthermore, it is also preferable that the injection nozzle 22 be installed at a position in the vicinity of the powder discharge port 23 in the powder supply device 19 (see FIG. 1). This is because the raw material powder 20 supplied from the powder supply device tends to be consolidated at the position near the powder discharge port 23 and the fluidity tends to be low.

  3A and 3B show another embodiment of the feed shoe 17. In the feed shoe 17 shown in FIG. 3A, a large number of partition plates 24 for agitating the raw material powder, which are provided on the inner wall of the wall portion 18, are arranged. The partition plate 24 forms a gentle angle with respect to the tangential direction of the rotating plate 13. The raw material powder flows and agitates by the partition plate 24 as shown by an arrow P in FIG. That is, the partition plate 20 acts as a static mixer. As a result, combined with fluidization by the gas injected from the injection nozzle 22, the raw material powder 20 is more uniformly filled into the die 30.

  In the feed shoe 17 shown in FIG. 3B, a rotary blade 40 for stirring the raw material powder is disposed in the feed shoe 17. In the figure, two rotary blades 40 are used. The rotating blade 40 has a rotating surface parallel to the rotating surface of the rotating disk 13. Each rotary blade 40 includes a plurality of blade portions 41. Each blade portion 41 extends radially from the rotation center of the rotary blade 40. The rotary blades 40 are arranged so that their blade portions 41 are engaged with each other when they rotate in opposite directions. Under such an arrangement state of the rotary vanes 40, the feed shoe 17 is constituted by an eight-shaped wall portion 18 surrounding both the rotary vanes 40.

  In the embodiment shown in FIG. 3B in which the feed shoe 17 has the above configuration, the raw material powder is fed into the feed shoe 17 while rotating the rotary blades 40 while the blade portions 41 of the rotary blades 40 are engaged with each other. Is further promoted in the stirring of the raw material powder, and its fluidity is further enhanced. As a result, in combination with fluidization by the gas injected from the injection nozzle 22, the flow of the raw material powder into the die 30 proceeds more smoothly, and the raw material powder is uniformly filled into the die 30.

  FIG. 4 shows still another embodiment of the feed shoe 17. This embodiment is a modification of the embodiment shown in FIG. In the present embodiment, the space for promoting the replacement of the air existing in the die 30 formed by the die hole 14 and the upper end surface of the lower punch 16 with the raw material powder filled in the die 30 is defined as the die 30. The partition plate 24 is provided with an air replacement portion 31 for forming on the opening. Specifically, the air replacement unit 31 is configured by a partition plate 24 erected so as to have openings in the upper and lower sides. The partition plate 24 includes an inner wall 17a of the feed shoe 17 and a projecting wall 33 that projects from the inner wall 17a and defines the space together with the inner wall 17a. The protruding wall 33 is composed of a front wall 33a located on the upstream side in the rotation direction of the turntable 13 and a back wall 33b located on the downstream side. The front wall 33a is provided so as to form a relatively small angle with respect to the tangent to the turntable. On the other hand, the back wall 33b is provided so as to form a relatively large angle, for example, an angle close to a right angle with respect to the tangent line of the turntable. As shown in FIG. 4, a plurality of air replacement portions 31 are provided in the feed shoe 17.

  When the partition plate 24 constituting the air replacement portion 31 is viewed in plan as shown in FIG. 4, a closed area 34 is formed by at least a part of the partition plate 24 and at least a part of the opening edge of the die 30. It has a shape like that. The closed area 34 may be formed at least once while one rotary die 30 passes below the one air replacement portion 31. In the closed area 34, the raw material powder is prevented from flowing in by the protruding wall 33. Therefore, the raw material powder flows into the mortar 30 through the opening area 35 which is an area other than the closed area 34 in the opening of the mortar 30. This state will be described with reference to FIG.

  As shown in FIG. 5, in the opening of the mortar 30, the closed area 34 is partitioned by the partition plate 24, so that the raw material powder 20 cannot flow into the mortar 30 through the closed area 34. On the other hand, since there is no such restriction in the opening area 35 other than the closed area 34 in the opening of the mortar 30, the raw material powder 20 flows into the mortar 30 through the opening area 35. Since air exists in the die 30, when the raw material powder 20 flows into the die 30, it is necessary to replace the existing air with the raw material powder 20. This replacement is smoothly performed through the air replacement space 36 existing on the closed area 34 where the flow of the raw material powder 20 into the die 30 is prevented. In other words, the air replacement space 36 facilitates replacement of the air present in the die 30 with the raw material powder 20 filled in the die 30. As a result, in combination with fluidization by the gas injected from the injection nozzle 22, the flow of the raw material powder into the die 30 proceeds more smoothly, and the raw material powder is uniformly filled into the die 30.

  As the shape of the protruding wall 33, for example, the form shown in FIGS. 6A and 6B can be adopted in addition to the form shown in FIG. 4. In the projecting wall 33 shown in FIG. 6A, the front wall 33a has an extending portion 33d that further extends downstream from the intersection 33c of the front wall 33a and the back wall 33b. This extending portion 33b further promotes stirring of the raw material powder and further improves the fluidity. In the projecting wall 33 shown in FIG. 6B, the back wall 33 b is curved in a convex shape toward the downstream side in the rotational direction of the rotating disk 13. Accordingly, there is an advantage that the raw material powder does not easily stay in the vicinity of the intersection 33e between the back wall 33b and the inner wall 17a of the feed shoe 17.

  FIG. 7 shows still another embodiment of the feed shoe 17. This embodiment is a modification of the embodiment shown in FIG. The present embodiment is different from the embodiment shown in FIG. 3B in the shape of the blade portion 41 of the rotary blade 40. As shown in FIG. 7, in the present embodiment, each blade portion 41 of the rotary blade 40 is formed with a through hole 42 penetrating vertically. The blade portion 41 having the through hole 42 is a closed area 34 in the embodiment shown in FIG. 4 described above, that is, an area where the raw material powder is prevented from flowing into the die 30. On the other hand, since there is no such restriction in the area 43 between the adjacent blade portions 41, the raw material powder 20 flows into the die 30 through the area 43. Then, the air replaced with the raw material powder 20 flowing into the mortar 30 through the area 43 is discharged to the outside through the through hole 42 which is an area where the inflow of the raw material powder is blocked. Thus, in this embodiment, the blade | wing part 41 which has the through-hole 42 has a function equivalent to the air replacement part 31 in embodiment shown in FIG. 4 mentioned above. That is, the air replacement part 31 is provided in the blade part 41. As a result, for the same reason as in the case of the embodiment shown in FIG. 4 described above, also in this embodiment, the raw material powder into the die 30 is combined with the fluidization by the gas injected from the injection nozzle 22. The inflow proceeds more smoothly, and the raw material powder is uniformly filled into the die 30.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above embodiment, the raw material powder is filled in a rotationally moving die, but instead, the raw material powder is filled in a die that moves in one direction or in a die that reciprocates linearly. Also good.

  In the embodiment shown in FIG. 3B and FIG. 7, two rotary blades 40 are used, but only one or three or more rotary blades may be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.

[Example 1]
The feed shoe shown in FIG. 3B was installed in the molding machine shown in FIG. 1, and the powder was filled in the die. As the filled powder, one having a flowability index of carr of 50 having low fluidity was used. The diameter of the mortar was 30 mm and the depth was 30 mm. The linear velocity of the filling part of the rotating disk (diameter 500 mm) was 50 m / min. Air was jetted from the jet nozzle 22 having an inner diameter of φ4 mm to flow the powder. The injection timing was continuous and the injection pressure was 0.05 MPa. The filling volume of the powder at the time of passing through the scraping plate 21 in FIG. 1 was 95% with respect to the volume of the die.

[Example 2]
The feed shoe shown in FIG. 3A was installed in the molding machine shown in FIG. 1, and powder was filled in the die. As the filled powder, one having a flowability index of carr of 50 having low fluidity was used. The diameter of the mortar was 30 mm and the depth was 30 mm. The linear velocity of the filling part of the rotating disk (diameter 500 mm) was 50 m / min. Air was jetted from the jet nozzle 22 having an inner diameter of φ4 mm to flow the powder. The injection timing was continuous and the injection pressure was 0.05 MPa. The filling volume of the powder at the time of passing through the scraping plate 21 in FIG. 1 was 90% with respect to the volume of the die.

Example 3
The feed shoe shown in FIG. 4 was installed in the molding machine shown in FIG. 1, and the powder was filled in the die. As the filled powder, one having a flowability index of carr of 50 having low fluidity was used. The diameter of the mortar was 30 mm and the depth was 30 mm. The linear velocity of the filling part of the rotating disk (diameter 500 mm) was 50 m / min. Air was jetted from the jet nozzle 22 having an inner diameter of φ4 mm to flow the powder. The injection timing was continuous and the injection pressure was 0.05 MPa. The filling volume of the powder at the time of passing through the scraping plate 21 in FIG. 1 was 97% with respect to the volume of the die.

Example 4
The feed shoe shown in FIG. 7 was installed in the molding machine shown in FIG. 1, and the powder was filled in the die. As the filled powder, one having a flowability index of carr of 50 having low fluidity was used. The diameter of the mortar was 30 mm and the depth was 30 mm. The linear velocity of the filling part of the rotating disk (diameter 500 mm) was 50 m / min. Air was jetted from the jet nozzle 22 having an inner diameter of φ4 mm to flow the powder. The injection timing was continuous and the injection pressure was 0.05 MPa. The filling volume of the powder at the time of passing through the scraping plate 21 in FIG. 1 was 97% with respect to the volume of the die.

[Comparative Example 1]
A feed shoe shown in FIG. 8A was installed in the molding machine shown in FIG. 1, and powder was filled in the die. This feed shoe is the same as that shown in FIG. 3A except that no air injection nozzle is attached. As the filled powder, one having a flowability index of carr of 50 having low fluidity was used. The diameter of the mortar was 30 mm and the depth was 30 mm. The linear velocity of the filling part of the rotating disk (diameter 500 mm) was 50 m / min. The filling volume of the powder at the time of passing through the scraping plate 21 in FIG. 1 was 60% with respect to the volume of the die.

[Comparative Example 2]
The feed shoe shown in FIG. 8B was installed in the molding machine shown in FIG. 1, and the powder was filled in the die. This feed shoe is the same as that shown in FIG. 3B except that no air injection nozzle is attached. As the filled powder, one having a flowability index of carr of 50 having low fluidity was used. The diameter of the mortar was 30 mm and the depth was 30 mm. The linear velocity of the filling part of the rotating disk (diameter 500 mm) was 50 m / min. The filling volume of the powder at the time of passing through the scraping plate 21 in FIG. 1 was 65% with respect to the volume of the die.

1 is a perspective view schematically showing a powder compression molding machine as one embodiment of the present invention. It is a longitudinal cross-sectional view which shows typically the part of the feed shoe in FIG. It is a top view (figure 2 equivalent figure) which shows another embodiment of a feed shoe. It is a top view (figure 2 equivalent figure) which shows another embodiment of a feed shoe. It is a longitudinal cross-sectional view which shows typically the part of the feed shoe in FIG. It is a top view (figure 2 equivalent view) which shows another embodiment of a feed shoe. It is a top view (Drawing 3 (b) equivalent figure) showing another embodiment of a feed shoe. It is a top view which shows the feed shoe used in Comparative Examples 1 and 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rotation type powder compression molding machine 13 Turntable 14 Mortar 15 Upper punch 16 Lower punch 17 Open feed shoe 18 Wall part 19 Powder supply apparatus 20 Raw material powder 22 Injection nozzle 30 Die 31 Air replacement part 32 Partition plate 40 Rotary blade

Claims (5)

A powder storage container in which at least a part of the upper surface and the lower surface is opened, and a powder filling container that is movable in the horizontal direction in proximity to the lower surface of the storage container, and the filling container opens the lower surface of the storage container In the powder filling apparatus in which the powder stored in the storage tank is filled into the filling container by free fall when passing through the area,
A powder filling apparatus comprising means for injecting gas toward the powder in the powder storage basket.   The powder filling apparatus according to claim 1, wherein a partition plate or a rotary blade for stirring the powder is disposed in the powder storage basket.   An air replacement section for forming a space on the opening of the filling container for promoting the replacement of the air present in the powder filling container with the powder filled in the filling container is the partition plate or the rotation The powder filling apparatus according to claim 2, wherein the powder filling apparatus is provided in a blade portion of the blade. The powder filling container is moved in the horizontal direction so as to be close to the lower surface of the powder storage tank in which at least a part of the upper surface and the lower surface is open, and when the filling container passes through the open area of the lower surface of the storage container, In the powder filling method of filling the filling container by free fall with the powder stored in the storage tank,
A powder filling method in which gas is injected toward a powder in a powder storage basket and filling is performed in a state where the powder is flowed. A powder storage trough with at least a part of the upper surface and the lower surface open, a rotary disc provided with a mortar hole penetrating in the thickness direction and movable in the horizontal direction in proximity to the lower surface of the storage trough, It is provided with upper and lower heels that are respectively slidable up and down and can be moved in the horizontal direction in synchronization with the movement of the rotating disk, and the tip of the lower heel is inserted into the mortar. In the powder compression molding machine in which the powder stored in the storage trough is filled into the mill by free fall when the millstone passes through the open area on the lower surface of the storage trough,
A powder compression molding machine provided with means for injecting gas toward the powder in the powder storage basket.

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