JP5546490B2 - Pellet dryer - Google Patents

Description

  The present invention relates to a pellet drying apparatus that heats and drys resin pellets.

  As a conventional pellet drying apparatus, for example, a rotary centrifugal dryer provided with a rotor having multistage blades rotating at high speed is known. However, a member that collides with resin pellets, particularly a rotor, is worn out early and has durability. There is a problem that it is inferior. In particular, in the case where the resin pellet is a fiber reinforced plastic mixed with glass fiber or the like, the above-described wear becomes significant due to the fiber.

  As another conventional pellet drying apparatus for solving the above problem, there is an apparatus described in Patent Document 1, for example. In this apparatus, resin pellets are supplied to one end side of a punching plate having a large number of through holes, and the resin pellets are transferred to the other end side of the punching plate and discharged by vibrating the punching plate. Here, by supplying hot air from below the punching plate, the resin pellets transferred on the punching plate by the hot air blown out from a large number of through holes are dried.

JP 2005-74935 A

  In the other conventional pellet drying apparatus, for example, a punching plate provided with a large number of circular through holes is used. However, in such a configuration using the punching plate, the resin pellet moves while avoiding the through hole portion. As a result, the resin pellets are not sufficiently exposed to the hot air rising from the through holes, and the resin pellets cannot be efficiently heated and dried.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a pellet drying apparatus that can efficiently heat and dry resin pellets.

  In order to achieve the above object, the pellet drying apparatus according to the present invention is supplied with resin pellets at one end and is vibrated to transfer the resin pellets from the one end to the other end. A pellet transfer plate in which a plurality of through grooves extending in a direction crossing the transfer direction are formed side by side in the transfer direction, a vibration device for vibrating the pellet transfer plate so as to transfer the resin pellets in the transfer direction, and Airflow generating means for flowing air for raising the temperature of the resin pellets from below to above in the through groove of the pellet transfer plate is provided.

  According to this configuration, the pellet transfer plate for transferring the resin pellets is provided with a through groove extending in the direction intersecting the transfer direction, and air for raising the temperature of the resin pellet is flowed through the through groove from below to above. As a result, an air curtain-shaped updraft (hot air) is formed on the pellet transfer plate. Since the resin pellets are transferred across the air curtain-like hot air, the resin pellets can be efficiently heated and dried, and the apparatus can be downsized.

  The air flow generating means holds the pellet transfer plate inside, has a pellet supply port for supplying resin pellets on the pellet transfer plate at one end, and has the other end of the pellet transfer plate at the other end. An air supply port for feeding heated air into the housing, comprising a housing having a pellet discharge port for discharging the resin pellets transferred to the housing, and an opening provided in a lower portion of the housing And an exhaust port for sucking out air in the housing.

  In this way, the pellet transfer plate is held inside the housing provided with the air supply port and the exhaust port, and the heated air is sent from the lower air supply port and the air is sucked out from the upper exhaust port. By constituting, it becomes easy to form a stable air flow that flows from the bottom to the top in the through groove of the pellet transfer plate, and the supply of resin pellets is not hindered.

  The air flow generating means is further connected to the air supply port, connected to the air supply means for sending heated air into the housing through the air supply port, and to the exhaust port. And an exhaust means for sucking out the air in the housing and discharging it to the outside.

  Thus, by having the air supply means for sending the heated air into the housing and the exhaust means for sucking out the air in the housing and discharging it to the outside, it flows from the bottom to the top in the through groove of the pellet transfer plate It becomes easy to form a stable air flow.

  In addition, the apparatus further includes an air flow dispersion plate disposed in the housing, below the pellet transfer plate and above the air supply port, facing the pellet transfer plate and having a plurality of through holes. It is preferable.

  According to this configuration, the heated air (hot air) fed into the housing from the air supply port is dispersed by passing through the plurality of through holes of the airflow dispersion plate and reaches the pellet transfer plate, thereby the pellet transfer plate. It becomes easy to send hot air almost uniformly over the entire surface.

  In addition, it is preferable that at least one of the air supply port and the exhaust port is provided in plural, and the air supply port and the exhaust port are arranged so as to be shifted in the transfer direction.

  With this configuration, it becomes easy to send hot air almost uniformly to the entire surface of the pellet transfer plate.

  Moreover, it is preferable that the said several through-groove of the said pellet transfer plate is formed along with the predetermined interval in the said transfer direction over the full length of the said pellet transfer plate.

  With this configuration, the resin pellets can be efficiently heated with hot air during the period in which the resin pellets are being transferred on the pellet transfer plate.

  Moreover, it is preferable that the said penetration groove | channel of each of the said pellet transfer plates extends in the direction orthogonal to the said transfer direction, and is formed over the substantially full width of the path | route through which the said resin pellet is transferred.

  With this configuration, all the resin pellets transferred on the pellet transfer plate can be reliably exposed to hot air.

  Moreover, it is preferable that the said pellet transfer board has a wedge shape in the cross section between the said through groove and the said through groove which adjoin the said transfer direction.

  With this configuration, the wind speed passing through the through groove can be increased with respect to the wind speed below the pellet transfer plate.

  The present invention has the configuration described above, and has an effect of providing a pellet drying apparatus that can efficiently heat and dry resin pellets.

(A) is the schematic plan view which looked at the pellet drying apparatus of embodiment of this invention from upper direction, (b) is a schematic side view of the pellet drying apparatus, (c) is the outline of the pellet drying apparatus. It is a front view. (A) is a top view which shows an example of the upper screen of the pellet drying apparatus of embodiment of this invention, (b) is sectional drawing of the same upper screen, (c) is the pellet drying apparatus of the same It is a top view which shows an example of a lower screen, (d) is a top view which shows the other example of the upper screen of the pellet drying apparatus.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout all the drawings, and redundant description thereof is omitted. Further, the present invention is not limited to the following embodiment.

(Embodiment)
Fig.1 (a) is the schematic plan view which looked at the pellet drying apparatus of embodiment of this invention from upper direction, FIG.1 (b) is a schematic side view of the pellet drying apparatus, FIG.1 (c) is FIG. It is a schematic front view of the pellet drying apparatus. In the following description, for convenience, the front, rear, left and right of the pellet drying apparatus will be described as shown in FIG.

  In the pellet drying apparatus of the present embodiment, a box-shaped apparatus body (housing) 20 is elastically supported on a base 9 by four front and rear elastic members 6 via four support legs 8 and the like. ing. The elastic member 6 is a spring, for example.

  The apparatus main body 20 has an upper portion at the rear (one end) opened to provide a pellet supply port 21 and a pellet discharge port 22 at the front (other end). In the apparatus main body 20, an upper screen 2 that is a pellet transfer plate and a lower screen 3 that is an airflow dispersion plate are fixed horizontally or substantially horizontally at predetermined intervals in the vertical direction. The upper and lower screens 2 and 3 are attached to the upper portion of the bottom plate portion 20 a of the apparatus main body 20.

  The bottom plate portion 20a of the apparatus main body 20 is formed in a funnel shape, and an air supply port 1 including an opening portion is provided in the approximate center. An air supply box 15 is connected to the air supply port 1 via a flexible tube 11 that can be expanded and contracted. The air supply box 15 is disposed on the base 9, and an opening 17 is provided at an upper portion thereof, and the flexible tube 11 is connected between the opening 17 and the air supply port 1 of the apparatus main body 20. ing. An air supply port 16 is provided on the side of the air supply box 15. The air supply port 16 is connected to the heater 13 via a pipe (not shown), and the heater 13 is connected to the air supply fan 12 via a pipe (not shown). The air taken in from the outside by the air supply fan 12 is sent to the heater 13 and heated to a predetermined temperature, and the air (hot air) heated by the heater 13 is supplied to the air supply box 15 and the flexible tube 11. Is sent into the apparatus main body 20 via Here, an air supply means is configured by the air supply fan 12, the heater 13, the air supply box 15, and a pipe (not shown). Note that the air supply box 15 may not be provided. In this case, the heater 13 and the flexible tube 11 are connected by a pipe (not shown). Further, as a heating means other than the heater 13, for example, a heat pump may be provided between the air supply fan 12 and the heater 13. In this case, the air may be heated to the first temperature T1 by the heat pump, and further heated to the predetermined second temperature T2 (> T1) by the heater 13.

  Further, the apparatus main body 20 is provided with vertical plates 4 and 4 which are fixed and hung inside the left and right side surfaces, and horizontal mounting plates 5 are provided at two positions before and after each vertical plate 4 and 4. . Each of the four horizontal mounting plates 5 in total is supported on a support leg 8 erected on the base 9 via a transfer plate 7 and an elastic member 6. Thereby, the apparatus main body 20 is elastically supported on the base 9. Note that the upper ends of the right two support legs 8 are connected by the transfer plate 7, and similarly, the upper ends of the two left support legs 8 are connected by the transfer plate 7.

  A vibration device mounting portion 14 made of a rod-like member or the like is disposed between the two vertical plates 4 and 4, and the vibration device 10 that vibrates the device main body 20 is mounted on the mounting portion 14. As the vibration device 10, a vibration motor is used here, but an electromagnetic device may be used. In this embodiment, by vibrating the apparatus main body 20, the upper screen 2 fixed to the apparatus main body 20 vibrates, and the resin pellet on the upper screen 2 supplied from the pellet supply port 21 moves forward (pellet discharge port 22. ).

  Two roof parts 23 having a reverse funnel shape (mountain shape) are provided on the upper surface portion of the apparatus main body 20, and an exhaust port 24 including an opening part is provided at the upper end of each roof part 23. Each exhaust port 24 is connected to an exhaust fan 25 via a pipe (not shown), and the air inside the apparatus main body 20 is sucked by the exhaust fan 25 and discharged to the outside. Here, the exhaust means is comprised by the exhaust fan 25 and piping which is not shown in figure.

  The air supply fan 12 is an air supply fan for sucking external air through an intake filter and sending air into the apparatus main body 20 through a heater 13 and an air supply box 15. The exhaust fan 25 is an exhaust fan for sucking out air in the apparatus main body 20 and discharging it to the outside of the apparatus.

  2A is a plan view showing an example of the upper screen 2, FIG. 2B is a cross-sectional view of the upper screen 2, and FIG. 2C is an upper screen 2 and an air supply port. 1 is a plan view showing an example of a lower screen 3 disposed between the first and second screens.

  As shown in FIGS. 2A and 2B, the upper screen 2 has a plurality of slits (through grooves) 2 s arranged at a predetermined interval L <b> 2 in the pellet transport direction Sp over the entire length of the upper screen 2. Is provided. Here, the slit 2s is provided so that its longitudinal direction is orthogonal to the pellet transfer direction Sp and substantially covers the entire width of the resin pellet transfer path, and the cross section between the adjacent slits 2s, 2s is a wedge shape (triangle). )It has become. A wedge wire screen may be used as such an upper screen 2. The width of the slit 2s (groove width of the through groove) L1 is a predetermined dimension smaller than the resin pellet, and is a dimension that prevents the resin pellet from passing through the slit 2s (a dimension that does not drop from the slit 2s). As an example, for a cylindrical resin pellet having a diameter of 3 mm and a height of 3 mm, the width L1 of the slit 2s is 0.5 mm, and the width L1 of the slit 2s is based on any dimension of the diameter and height of the resin pellet. Is also small.

  Further, as shown in FIG. 2C, for example, a porous metal plate in which a plurality of round through holes Hb and Hs are opened in a staggered manner on the entire surface of the metal plate is used for the lower screen 3. Here, in order to supply the heated air (hot air) fed from the air supply port 1 almost uniformly to the entire surface of the upper screen 2, the lower screen 3 is connected to the upstream portion 3a, the midstream portion 3c, and the downstream portion 3b. Dividing into three regions, the hole diameters and arrangement pitches of the through holes Hb in the upstream and downstream portions 3a, 3b and the through holes Hs in the midstream portion 3c are made different. That is, the through hole Hs immediately above the air supply port 1 and the vicinity thereof (middle flow portion 3c), and the other region, that is, the through hole in the region far from the air supply port 1 (upstream and downstream portions 3a, 3b). The hole diameter and arrangement pitch with Hb are varied. However, the configuration is not limited to this. Further, the arrangement shape of the plurality of through holes Hb and Hs is not limited to the staggered shape.

  The operation of the pellet drying apparatus configured as described above will be described.

  During operation of the pellet drying apparatus, the vibration device 10, the air supply fan 12, and the exhaust fan 25 are always driven. When the apparatus main body 20 vibrates by the vibration device 10, the upper screen 2 also vibrates. That is, the resin pellets supplied from the pellet supply port 21 are placed on the upper screen 2 and transferred toward the pellet discharge port 22 by the vibration of the upper screen 2. Here, the apparatus main body 20 to which the upper screen 2 is fixed vibrates so as to reciprocate between a front diagonally upper position and a rear diagonally lower position.

  Further, the outside air taken in by the air supply fan 12 is heated by the heater 13 and sent into the apparatus main body 20, and the air inside the apparatus main body 20 is sucked out by the exhaust fan 25 and discharged to the outside. Here, the air sent into the apparatus main body 20 from the air supply port 1 passes through the through holes Hb and Hs of the lower screen 3, and further passes through the slit 2 s of the upper screen 2 and is sucked out from the exhaust port 24. Then, it is discharged to the outside by the exhaust fan 25. At this time, since the air sent into the apparatus main body 20 is dispersed by the lower screen 3 and reaches the upper screen 2, air (hot air) Sa (FIG. 2B) is almost uniformly distributed over the entire surface of the upper screen 2. It becomes possible to send.

  Since the upper screen 2 is provided with a large number of slits 2s orthogonal to the pellet transfer direction Sp and over substantially the entire width of the transfer path, the resin pellets to be transferred must pass over the slits 2s. At that time, the resin pellets are necessarily exposed to the air rising from the slit 2s (hot air), so that the resin pellets can be efficiently heated and dried.

  Experiments were conducted to verify this effect. In this experiment, the upper screen 2 has a width of 200 mm, a length of 2850 mm, a width L1 of the slit 2s of 0.5 mm, and an interval L2 between the adjacent slits 2s and 2s of 1.5 mm. It was.

  The width and length of the lower screen 3 are the same as those of the upper screen 2. The lower screen 3 has regions (upstream part 3a, midstream part 3c, and downstream part 3b) divided into three equal parts in the length direction. The upstream and downstream portions 3a and 3b have a through hole Hb diameter of 2 mm, a pitch L3 of through holes Hb adjacent in the width direction of the screen is 3.5 mm, and a row of through holes Hb adjacent in the length direction of the screen. The pitch L4 is 3 mm, the midstream portion 3c has a through hole Hs diameter of 3 mm, a pitch L5 of the through holes Hs adjacent in the width direction of the screen is 5 mm, and a row of through holes Hs adjacent in the length direction of the screen. A pitch L6 of 4.3 mm was used.

  The air flow was adjusted by inverter control of the air supply fan 12 and the exhaust fan 25 so that the wind speed passing through the slit 2s of the upper screen 2 was 1.5 to 3.0 m / sec. The wind speed passing through the slit 2s is preferably set to a wind speed (for example, the above-described wind speed) in which the resin pellets are not scattered and the heating (temperature increase) effect is enhanced.

  In this experiment, columnar resin pellets having a diameter of 3 mm and a height of 3 mm were prepared in advance and supplied to the pellet supply port 21 using a quantitative supply device. The resin pellet used here is produced from a fiber reinforced plastic in which glass fibers are mixed into PPS (polyphenylene sulfide resin).

  When the amount of resin pellets supplied to the pellet supply port 21 by the quantitative supply device is 200 kg per hour and the temperature of the resin pellets supplied to the pellet supply port 21 is 28 ° C., the temperature of the resin pellets discharged from the pellet discharge port 22 is It became 131 degreeC. Further, the moisture content of the resin pellets was changed from 7.4% to 0.14%. The hot air temperature at the air supply port 1 of the apparatus main body 20 was 145 ° C. The outside air temperature was 29.8 ° C. and the humidity was 62.5%.

  As shown in the above experimental results, if the pellet drying apparatus of the present embodiment is used, the resin pellets can be efficiently heated and dried.

  In the present embodiment, the upper screen 2 that transfers the resin pellets is provided with a slit 2s that is long in the direction orthogonal to the pellet transfer direction Sp as an air passage. As the air heated from below passes through the slit 2s, an air curtain-like (planar) updraft (hot air) is formed on the upper screen 2, and the resin pellets are transported across the air curtain-like hot air. The Accordingly, since the resin pellets transferred on the upper screen 2 are always exposed to hot air, the resin pellets can be efficiently heated and dried. Therefore, the length of the apparatus main body 20 in the pellet transfer direction Sp can be shortened, and the apparatus can be downsized.

  In the pellet drying apparatus of the present embodiment, for example, a strand (string-like resin) obtained by melting and kneading a resin material and an additive and extruding from the tip of the extruder is solidified by cooling and solidifying in water or by spraying cooling water. Then, it can be used when drying cylindrical resin pellets produced by cutting with a strand cutting device. In this case, the resin pellets generated by the strand cutting device are supplied to the pellet supply port 21, and the adhering moisture on the resin pellets is efficiently removed by the air curtain-like (planar) hot air formed on the upper screen 2. Can be dried.

  For example, when the stored resin pellets are dried before being subjected to molding, the moisture absorbed in the resin pellets is efficiently removed and dried by using the pellet drying apparatus of this embodiment. be able to.

  For example, when the stored amorphous (amorphous) resin pellets are crystallized before being subjected to molding, the pellet drying apparatus of this embodiment can be used. In this case, the resin pellet is easily fused when the glass transition point is exceeded, but the resin pellet supplied from the pellet supply port 21 is transferred while vibrating on the upper screen 2, so that the resin pellets are fused. Without being heated, the resin pellets can be crystallized by being heated by hot air. For example, in the case of PPS resin pellets, crystallization can be performed by setting the temperature of the hot air to, for example, about 140 to 150 ° C.

  In the present embodiment, as the upper screen 2, as shown in FIG. 2B, a cross section between adjacent slits 2s is wedge-shaped, but the present invention is not limited to this. You may use that whose cross section between 2s is a rectangle or a square. Since the cross section between the slits 2s is wedge-shaped as in this embodiment, the wind speed when passing through the slit 2s with respect to the wind speed below the upper screen 2 is increased. The air volume of the fan 25 can be reduced.

  Further, the slit 2s does not necessarily have to be orthogonal to the pellet transfer direction Sp, and may be a slit extending in a direction crossing the pellet transfer direction Sp, that is, a slit long in the direction crossing the pellet transfer direction Sp.

  Moreover, as shown in FIG.2 (d), you may use the upper screen 2a by which the slit 2s was divided | segmented into plurality by the width direction (direction orthogonal to the pellet transfer direction Sp) of a screen. However, in order to efficiently raise the temperature and dry the resin pellets, it is preferable that the divided portions d1 and d2 of the adjacent slit rows arranged in the pellet transfer direction Sp are not adjacent to each other and arranged as far as possible. That is, it is preferable that the divided portions d1 and d2 are arranged as far apart as possible because the resin pellets are exposed to the hot air from the slit 2s without continuously passing through the divided portions d1 and d2.

  In the present embodiment, as shown in FIG. 2 (c), the lower screen 3 is divided into three regions (upstream portion 3a, downstream portion 3b, and the size of the through holes (Hb, Hs) and the arrangement pitch thereof. Although it is configured to have the midstream portion 3c), the configuration is not limited to the above as long as hot air can be supplied almost evenly to the entire surface of the upper screen 2. For example, even when all the through holes of the lower screen 3 have the same diameter and arrangement pitch, if the hot air can be supplied almost uniformly to the entire surface of the upper screen 2 by using another means, The through holes may have the same diameter. As said other means, means, such as a board (blade board) etc. which guide a hot air from the air inlet 1, to the upstream and downstream of the pellet transfer direction Sp, can be considered, for example. Moreover, even if all the through holes of the lower screen 2 have the same diameter and arrangement pitch without using a means such as a blade plate, the hot air is supplied to the upper portion by arranging a plurality of air supply ports 1 in the pellet transfer direction Sp. It can also be configured to supply almost evenly to the entire surface of the screen 2. Moreover, it is good also as a structure which changed the magnitude | size, arrangement | positioning pitch, etc. of the through-hole of the lower screen 3 according to area | regions (for example, the upstream part 3a, the downstream part 3b, the midstream part 3c) while providing other means, such as a blade. . Further, all the through holes of the lower screen 3 may have the same diameter, and different arrangement pitches may be used depending on regions (for example, the upstream portion 3a, the downstream portion 3b, and the midstream portion 3c).

  In the present embodiment, the apparatus main body 20 is provided with one air supply port 1 and two exhaust ports 24, but is not limited thereto. For example, if the air supply port and the exhaust port are on the same vertical line, the air sucked from the air supply port easily reaches the exhaust port and is difficult to spread, so the air supply port and the exhaust port are on the same vertical line. However, it is preferable that they are arranged shifted in the pellet transfer direction (front-rear direction) Sp. Further, in the present embodiment, the number of exhaust ports is made larger than the number of air supply ports of the apparatus main body 20, but the number of air supply ports may be made larger than the number of exhaust ports. Further, the number of air supply ports and the number of exhaust ports may be equal to one or more. For example, in the case of a small apparatus, both the air supply port and the air exhaust port may be provided.

  In the present embodiment, the apparatus main body 20 to which the upper screen 2 is fixed is vibrated to vibrate the upper screen 2 and transfer the resin pellets. However, the upper screen 2 is separated from the apparatus main body 20. Alternatively, the resin pellets may be transferred by vibrating only the upper screen 2.

  In the present embodiment, the air volume of the supply fan 12 and the exhaust fan 24, the heating temperature of the heater 13, and the vibration frequency and amplitude of the vibration device 10 can be adjusted. Further, for example, a temperature sensor for detecting the temperature in the air supply box 15 or the temperature in the air supply port 1 is provided, and the heating temperature of the heater 13 is set so that the temperature of the air fed into the apparatus body 20 becomes a desired temperature. Etc. may be adjusted.

  The pellet drying apparatus according to the present invention is useful as an apparatus for efficiently raising the temperature of resin pellets.

DESCRIPTION OF SYMBOLS 1 Air supply port 2 Upper screen 2s Slit 3 Lower screen Hb, Hs Through-hole 24 Exhaust port 10 Vibrating device 12 Air supply fan 13 Heater 15 Air supply box 20 Main body 21 Pellet supply port 22 Pellet discharge port 25 Exhaust fan

Claims (7)

Resin pellets are supplied to one end and are vibrated to transfer the resin pellets from the one end to the other end, and through grooves extending in a direction intersecting the transfer direction, which is the transfer direction, are arranged in the transfer direction. A plurality of pellet transfer plates formed in a wedge shape with a cross section between the through grooves and the through grooves adjacent to each other in the transfer direction ;
A vibration device for vibrating the pellet transfer plate so as to transfer the resin pellets in the transfer direction;
An airflow generating means for flowing air for raising the temperature of the resin pellets from above to below in the through groove of the pellet transfer plate ;
A pellet drying apparatus configured to form an air curtain-shaped rising airflow on the pellet transfer plate by passing the air through the through groove of the pellet transfer plate . The airflow generating means is
Holds the pellet transfer plate inside, has a pellet supply port for supplying resin pellets on the pellet transfer plate at one end, and discharges the resin pellet transferred to the other end of the pellet transfer plate at the other end A housing having a pellet outlet for
An air supply port for sending heated air into the housing, comprising an opening provided in the lower portion of the housing;
The pellet drying apparatus according to claim 1, comprising an opening provided at an upper portion of the casing, and having an exhaust port for sucking out air in the casing. The airflow generation means further includes
An air supply means connected to the air supply port and for sending heated air into the housing through the air supply port;
The pellet drying apparatus according to claim 2, further comprising an exhaust unit that is connected to the exhaust port and sucks out air in the housing from the exhaust port and discharges the air to the outside.   The air flow dispersion plate further comprising an airflow distribution plate disposed in the housing, below the pellet transfer plate and above the air supply port, facing the pellet transfer plate and having a plurality of through holes. The pellet drying apparatus according to 2 or 3.   The pellet according to claim 2 or 3, wherein a plurality of at least one of the air supply port and the exhaust port are provided, and the air supply port and the exhaust port are arranged to be shifted in the transfer direction. Drying equipment. A plurality of said through groove of the pellet transfer plate, the pellet transfer plate over the entire length of the formed side by side at predetermined intervals in the transport direction, the pellets dried according to any one of claims 1-5 apparatus. The through-groove of each of the pellet transfer plates extends in a direction orthogonal to the transfer direction, and is formed over substantially the entire width of the path through which the resin pellets are transferred . The pellet drying apparatus described in 1.

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