JP5161724B2 - Pan coating apparatus and pan coating method - Google Patents

Description

  The present invention relates to a pan-type coating apparatus that performs a coating process on tablets and powders, and more particularly, to a pan coating apparatus that reduces adhesion of sugar coating liquid to the inner surface of the bread during sugar coating.

  2. Description of the Related Art Conventionally, a coating apparatus using a rotating drum is known as a manufacturing apparatus for pharmaceuticals and foods. For example, Patent Document 1 discloses a device that rotates a rotary drum having a polygonal cross section (here, an octagon) around a horizontal axis. Such a rotating drum is also called a coating pan, and a spray device for supplying a coating liquid is disposed inside. The granular material thrown into the rotating drum rolls with the rotation of the drum, and a coating liquid such as a sugar coating liquid is sprayed on the surface thereof from the spray device. At that time, hot air and cold air are appropriately supplied and exhausted into the rotating drum, and the formation and drying of the coating layer are promoted.

  When the sugar coating process is performed with such a coating apparatus, first, an object to be processed such as a tablet is stored in a rotating drum. Thereafter, the coating liquid (sugar coating liquid) is supplied into the drum while rotating the rotating drum, and adhered to the outer periphery of the object to be processed. During the coating process, hot air of about 50 to 100 ° C. is appropriately fed to the object to be processed, and the sugar coating liquid is evaporated and dried on the surface of the object to be processed by this hot air to form a coating layer. Then, the operation of adding the coating liquid and drying is repeated, and a number of coating layers are stacked on the outer periphery of the tablet to form a sugar coating layer.

  However, during the coating process, the rotating drum itself is also heated by the warm air, so that the sugar coating liquid is solidified and adheres to the inner surface of the rotating drum. If this solidified material peels off from the drum inner surface and adheres to the product, it will cause defective products such as bots and protrusions. For this reason, it is necessary to appropriately clean the inside of the rotating drum during the coating process. For example, in sugar coating, the rotating drum is stopped when the amount of sugar coating residue attached to the drum inner surface increases, and the adhering residue is removed from the drum. Are discharged.

However, since such a cleaning operation is performed by appropriately interrupting the coating process, the processing efficiency is lowered and the number of work steps is increased. Therefore, in order to suppress the solidification / adhesion of the sugar coating liquid on the inner surface of the rotating drum, Patent Document 2 describes a configuration in which an injection nozzle is installed on the outer side of the rotating drum and cold water is injected from there onto the rotating drum. . In the apparatus of Patent Document 2, the rotating drum is cooled during the sugar coating process, the amount of sugar coating residue attached to the inner surface of the drum is reduced, and the processing efficiency and work man-hours are improved.
Japanese Unexamined Patent Publication No. 2007-203228 JP 2004-148292 A JP 2007-160190 A

  On the other hand, in recent years, since the apparatus configuration is simple and maintenance is easy, so-called jacketless type coating apparatuses in which a jacket for air supply and exhaust is eliminated from the outer periphery of the drum have been used. This jacketless type apparatus is configured to introduce air from an opening at an end portion in the axial direction of the drum, and to discharge air that has passed through the workpiece layer from a predetermined portion on the side of the drum. In this case, the entire circumference of the straight drum portion at the center of the drum has a ventilation structure, and has a full punching structure formed of a perforated plate such as a punching metal.

  However, when cold water is sprayed on the outer periphery of the drum as in Patent Document 2 in a coating apparatus having such a full-punch type rotary drum, the rotary drum has a ventilation structure, so that the cold water reaches the inside of the drum. The problem of intrusion occurs. When cooling water flows into the drum, the object to be processed such as a tablet gets wet, which is not preferable for the coating process. In this respect, since the apparatus of Patent Document 2 uses a rotating drum having no air permeability, even if cold water is sprayed onto the outer periphery of the drum, there is no effect on the inner workpiece, but the entire punching as described above is performed. In the drum of the configuration, the water inside the drum is inevitable. For this reason, the actual situation is that the jacketless type apparatus using the entire punching drum has the advantage of simple structure and easy maintenance, but is not widely spread in Japan.

  An object of the present invention is to suppress the adhesion of sugar coatings to the inner surface of a drum during coating processing in a coating device using a rotating drum having a full-surface punching configuration, such as a jacketless type coating device, and to improve processing efficiency and man-hours. It is to improve.

  A pan coating apparatus according to the present invention includes a rotary drum that is rotatably provided about a substantially horizontal rotation axis and has a vent hole in at least a part of an outer peripheral portion thereof, and a housing that houses the rotary drum. The pan coating apparatus includes a drum cooling unit that is installed in the casing and sprays a cooling medium containing fine cooling mist on the outside of the rotating drum.

  In the present invention, the cooling medium containing fine cooling mist is sprayed to the outside of the rotating drum by the drum cooling means installed in the casing, thereby cooling the rotating drum. Since the cooling mist is fine, very little moisture enters the drum due to the cooling mist, and the inside of the drum is difficult to wet even if mist spraying is performed on the rotating drum having the vent holes. For this reason, the drum can be directly cooled even in the coating apparatus using the entire punching drum. This makes it difficult for the solidified coating liquid to adhere to the inner surface of the drum during the coating process, thereby reducing the number of drum cleaning operations and improving the production efficiency.

  In the pan coating apparatus, fine water droplets having an average particle diameter of 5 μm or more and 100 μm or less may be used as the cooling mist. Further, the cooling medium is sprayed by a spray gun installed in the rotary drum, and the spray area of the cooling medium in the outer peripheral portion of the rotary drum is preferably 50 mm to 400 mm in diameter per spray gun, more preferably the diameter. You may set to about 300 mm.

  On the other hand, the pan coating method of the present invention is provided so as to be rotatable about a substantially horizontal rotation axis, and has a rotary drum having a vent hole in at least a part of the outer peripheral portion, a housing for housing the rotary drum, In a pan coating apparatus, which is provided in a casing and includes a drum cooling means for spraying a cooling medium containing fine cooling mist to the outside of the rotating drum, a coating liquid is supplied into the rotating drum to rotate the rotating drum. A pan coating method for performing a coating process on an object to be processed in a drum, wherein (a) the cooling medium is sprayed on the outer side of the rotating drum without supplying and exhausting air to the rotating drum to cool the rotating drum. A precooling step, (b) rotating the rotating drum without supplying / exhausting the rotating drum to the object to be processed while rotating the rotating drum. A spraying step of spraying a coating liquid; (c) a pausing step of rotating the rotating drum without supplying and exhausting the rotating drum to spread the coating liquid on the object to be processed; and (d) a rotating drum. It has each process of the drying process which rotates the said rotating drum, supplying and exhausting, and drying and solidifying the said coating liquid on the said to-be-processed object.

  In the present invention, since the spraying process is performed in a state where the rotating drum is cooled in the precooling process, the solidified product of the coating liquid is difficult to adhere to the drum inner surface during the spraying process. Also, when these steps (a) to (d) are repeated, the rotating drum warmed in the drying step is cooled in the pre-cooling step, so that the transition is made in a short time during the next spraying step. And the processing time can be shortened. Furthermore, since the rotating drum is cooled by a cooling medium containing fine cooling mist, the moisture entering the drum by the cooling mist is very little, and even if mist spraying is performed on the rotating drum having a vent, Is difficult to wet. For this reason, the drum can be directly cooled even in the coating apparatus using the entire punching drum.

  In the pan coating method, the cooling medium may be sprayed to the outside of the rotating drum in the spraying process in addition to the pre-cooling process, whereby the rotating drum is cooled during the spraying process, and coating during the spraying process is performed. Adherence of solidified liquid is suppressed. In addition to the precooling step, the cooling medium may be sprayed to the outside of the rotating drum also in the spraying step and the pause step, whereby the rotating drum is cooled during the spraying step and the pause step. The adhesion of the solidified coating liquid during the process or the pause process is suppressed. Note that if the cooling medium is sprayed when dry air is not ventilated and the inside of the rotating drum is in a high humidity state as in the spraying process or the pause process, even if moisture enters the drum due to mist spraying, the effect There is almost no.

  In the pan coating method, fine water droplets having an average particle diameter of 5 μm or more and 100 μm or less may be used as the cooling mist. The spray area of the cooling medium on the outer periphery of the rotating drum may preferably be set to a diameter of 50 mm to 400 mm, more preferably about 300 mm per drum cooling means.

  According to the pan coating apparatus of the present invention, the rotating drum is accommodated in the pan coating apparatus provided with a rotating drum that is provided so as to be rotatable about a substantially horizontal rotation axis and has a vent hole in at least a part of the outer peripheral portion. Since the drum cooling means for spraying the cooling medium containing the fine cooling mist on the outside of the rotating drum is installed in the casing, the rotating drum can be directly cooled by the cooling mist. This makes it difficult for the solidified coating liquid to adhere to the inner surface of the drum during the coating process, thereby reducing the number of drum cleaning operations and improving the production efficiency. In addition, since the cooling mist is fine, very little water enters the drum due to this cooling mist, and even if mist spraying is performed on a rotating drum with a vent hole, the inside of the drum is not easily wetted. In a coating apparatus using a drum, the drum can be directly cooled.

  According to the pan coating method of the present invention, a rotating drum is accommodated in a pan coating apparatus provided with a rotating drum that is provided to be rotatable about a substantially horizontal rotation axis and has a vent hole in at least a part of the outer peripheral portion. A drum cooling means for spraying a cooling medium containing fine cooling mist on the outside of the rotating drum, and a pre-cooling step for spraying the cooling medium on the rotating drum without supplying and exhausting in the apparatus; A spraying process for spraying the coating liquid onto the workpiece while rotating the drum without supplying / exhausting the rotating drum, a pause process for rotating the drum without supplying / exhausting the rotating drum, and a supply of the rotating drum And a drying process in which the rotating drum is rotated while exhausting, so that the rotating drum is cooled in the pre-cooling process. It can enforce laser process, solidification of the coating liquid can be prevented from adhering to the inner surface of the drum at the time of spraying process. Even when these steps are repeated, the rotating drum warmed in the drying step is cooled in the pre-cooling step, so that it can be transferred in a short time during the next spraying step, and the processing time can be shortened. Figured. Furthermore, since the rotating drum is cooled by a cooling medium containing fine cooling mist, the moisture entering the drum by the cooling mist is very little, and even if mist spraying is performed on the rotating drum having a vent, Is difficult to wet, and the drum can be directly cooled even in a coating apparatus using a full-punch type rotary drum.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a right side view showing a configuration of a pan coating apparatus 10 (hereinafter abbreviated as a coating apparatus 10) according to an embodiment of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a plan view (top view). is there. The apparatus shown in FIG. 1 is a jacketless type coating apparatus using a so-called full punching type rotating drum, and a processing object such as a tablet is placed in a rotating drum (coating pan, hereinafter abbreviated as drum) 1. It is configured to perform a coating process on an object to be processed by housing and spraying a coating liquid thereon.

  As shown in FIGS. 1 to 4, the coating apparatus 10 has a configuration in which the drum 1 is rotatably installed at the center of the housing 2. The drum 1 rotates around a substantially horizontal rotation axis O, and an object to be processed 3 such as gum, chocolate, or tablet is placed in the drum 1. In general, a drum (tilt pan) whose rotation axis is inclined with respect to the horizontal has a larger accommodation amount and a larger processing amount than a drum that rotates about the horizontal axis. On the other hand, in the inclined drum, gravity classification occurs in the object to be processed in the drum, so that the variation in coating between products becomes large and is not suitable for precise coating processing. In addition, although the filling rate of the object to be processed in the drum is increased, the stored object to be processed has a layer height and its own weight is increased, so that damage to the raw material tablets is also increased. In this respect, the horizontal rotation type drum has less of these problems and is suitable for high-quality coating processing.

  FIG. 4A is a side view of the drum 1. The drum 1 includes a cylindrical body portion 4 and a truncated cone-shaped conical portion 5 formed at both ends of the body portion 4. The body 4 is formed of a stainless steel perforated plate, and the outer periphery of the body 4 is configured to be ventilated by a large number of ventilation holes 6. The conical part 5 is formed of a stainless steel plate without holes, and a front opening 7 is formed at one end thereof. The other end side is closed by an end plate 8, and a rotating shaft 9 is attached.

  On the other hand, a baffle 26 is installed inside the drum 1 to disturb the rolling flow of the object to be processed and to promote the mixing and stirring efficiency. FIG. 4B is an explanatory diagram showing the configuration of the baffle 26, and the baffle 26 is also formed of a stainless steel porous plate having a large number of ventilation holes 27. As shown in FIG. 4B, the baffle 26 is formed in a mountain shape having a substantially triangular cross section, and is fixed to a baffle mounting hole 28 formed in the body portion 4. The baffle attachment hole 28 is a rectangular opening, and the baffle 26 is attached by welding its bottom edge to the periphery of the baffle attachment hole 28. The baffle 26 is disposed so as to protrude into the drum 1, whereby a breathable three-dimensional baffle is erected inside the drum 1.

  Thus, if the baffle 26 itself has a three-dimensional ventilation structure, not only the effect of promoting mixing and stirring of the object to be processed but also the loss of ventilation of the processing gas can be eliminated. That is, in the case of a baffle that does not have a ventilation structure, when the processing gas is exhausted from the inside of the drum, the baffle portion may become a barrier to prevent ventilation, and pulsation may occur in the exhaust. In that respect, in the coating apparatus 10, since the baffle 26 has a ventilation structure, air circulation is not hindered and exhaust pulsation can be suppressed. Therefore, the effect of reducing the pulsation of the ventilation air by the jacketless structure can be further improved, and the coating process can be performed without disturbing the spray pattern. Further, the heat dissipation area of the drum 1 is expanded by the baffle 26, and the baffle 26 and the body 4 are uniformly cooled by mist cooling described later, so that the drum cooling efficiency is also improved.

  A drum rotating mechanism (not shown) using an electric drum driving motor is disposed on the right side of the drum 1 in FIG. The rotating shaft 9 is fixed to the right end side (the other end side) of the drum 1 as described above, and a sprocket (not shown) is attached to the rotating shaft 9. The sprocket is connected to a motor-side sprocket installed in the housing 2 via a chain. When the motor is rotated, the drum 1 is chain-driven along with the rotation, and rotates about the rotation axis O. 1 and 4, the left end side of the drum 1 is supported by a roller (not shown).

  The housing 2 has a double structure in which a drum chamber 29 for accommodating the drum 1 is provided, and a sink 30 is provided in the lower portion of the drum chamber 29. The sink 30 has a watertight structure with a drain port (not shown) at the bottom, and can store a cleaning liquid such as water therein. When cleaning the coating apparatus 10, the cleaning liquid is stored in the sink 30, and the drum 1 is rotated there to store and clean the inside and outside of the drum. After the drum cleaning, the cleaning liquid is discharged from the above-described drain port, and treatments such as rinsing and drying are appropriately performed.

  The front surface of the housing 2 (left side in FIG. 1, see FIG. 2) has a three-part structure, and a chamber door 11 is disposed at the center thereof. The chamber door 11 is a rectangular parallelepiped box-shaped member having a size of about 900 mm × 1100 mm × 200 mm, and is supported by a hinge 12 so as to be freely opened and closed. The chamber door 11 has a box shape in which the surface on the front wall 2a side of the housing 2 is opened, and an air supply chamber 13 is formed inside. The air supply chamber 13 is disposed in front of the front opening 7 of the drum 1, and the cross-sectional area facing the front opening 7 of the air supply chamber 13 is about 5 with respect to that of the front opening 7 (inner diameter of about 500 mm). (2 times or more is preferable, and about 8 times is preferable considering the case size). The front side of the chamber door 11 is a curved surface, and accordingly, the front inner wall 13a of the air supply chamber 13 is also a curved surface. Thereby, while creating the external appearance with the design characteristic, the volume expansion in the air supply chamber 13 is achieved.

  An inspection door 15 provided with a monitoring window 14 at the center is further attached to the front surface of the chamber door 11. On both sides of the inspection door 15, grip bars 16 extending in the vertical direction are attached. Further, a product discharge port 17 for taking out the product after the completion of processing is attached to the lower portion of the chamber door 11. In the coating apparatus 10, the grip bars 16 arranged on both sides of the inspection door 15 constitute an H-shaped design that does not exist in the conventional coating apparatus on the front surface, and design accents are formed (see FIG. 2).

  The chamber door 11 is attached to the housing 2 so as to be opened to the right, and can be opened from the front side of the apparatus with the grip bar 16 on the front surface of the chamber. FIG. 5 is a plan view showing a state in which the chamber door 11 is opened, and FIG. 6 is a front view of the coating apparatus in that state. As shown in FIG. 5, when the chamber door 11 is opened, the housing front wall 2a is exposed, and the front opening 7 formed at the end of the drum 1 is opened. An air supply hole 18 is further provided above the front opening 7 of the housing front wall 2a. The coating apparatus 10 employs an internal air supply structure, and the air supply hole 18 communicates with an air supply port 21 provided in the upper surface 2b of the housing via an air supply duct 19 disposed in the housing 2. ing. As shown in FIG. 1, in the coating apparatus 10, an air supply duct 19 is bent in an empty space formed above the drum conical portion 5 in the housing 2, so that space saving of the apparatus and air by the bent duct can be achieved. The flow velocity is reduced.

  A wind direction plate 22 is attached to the front surface of the air supply hole 18. 7A is a front view of the wind direction plate 22, and FIG. 7B is a cross-sectional view thereof. The right side of FIG. As shown in FIG. 7A, the wind direction plate 22 has a configuration in which a plurality of louvers 24 (for example, a width of 30 mm) are welded and fixed inside a cylindrical frame body 23 (for example, an inner diameter of 200 mm). . The louver 24 is attached with an inclination of 60 °, for example, with respect to the end surface of the frame body, and the air (dry air) supplied from the air supply port 21 is rectified downward by the wind direction plate 22 and is provided in the air supply hole. 18 is discharged.

  In the coating apparatus 10, when the chamber door 11 is closed, the front opening 7 of the drum 1 faces and communicates with the air supply chamber 13. Accordingly, the air supplied to the air supply port 21 flows into the air supply chamber 13 while being rectified by the wind direction plate 22, and is supplied from there through the front opening 7 into the drum 1. That is, the coating apparatus 10 supplies air to the drum 1 from the air supply duct 19 through the large volume air supply chamber 13. For this reason, the flow rate of the air supplied into the drum can be sufficiently lowered and stabilized even when a large amount of air is ventilated.

  In this way, the air supply chamber 13 acts as a buffer portion (buffer) for the air supplied from the air supply duct 19, where the air flow velocity decreases and the flow velocity at the front opening 7 is also uniform throughout the cross section. It becomes. In the coating apparatus 10, since the front inner wall 13 a of the air supply chamber 13 has a curved shape, the air supplied from the air supply duct 19 hits the curved front inner wall 13 a facing the air supply hole 18 and is diffused. Mild airflow. In addition, in the apparatus, since the airflow direction plate 22 is attached to the air supply hole 18, the flow velocity is suppressed and the flow is adjusted even when it flows into the air supply chamber 13, so that the buffering effect by the air supply chamber 13 is further improved. Enhanced. Therefore, in the coating apparatus 10, the air supply is milder than that of the conventional apparatus, and the tablets are supplied and exhausted at a uniform flow rate and flow rate.

  Here, when air is supplied by connecting an air supply duct to the drum opening as in a conventional coating apparatus, the flow rate of air supplied into the drum becomes non-uniform. If the supply air is disturbed in the coating device, the uneven distribution of the supply air causes a disturbance in the spray mist flow of the coating liquid, which not only prevents spraying uniformly on the tablet, but also causes the spray mist to dry before reaching the tablet. Dry mist adheres to the drum and causes dirt. In this case, in order to sufficiently reduce and stabilize the flow rate, it is necessary to provide a straight drum portion that is long in the axial direction at the drum opening, and the distance from the mouth of the drum to the product layer becomes long, and the workability is remarkably deteriorated. At the same time, the device itself becomes larger.

  In that respect, the coating apparatus 10 can perform the coating process without disturbing the spray pattern in the drum due to the stabilization of the air flow, thereby reducing the coating unevenness and improving the product quality. In addition, scattering of coating dust is reduced, and the number of drum cleaning steps can be reduced. Furthermore, since a long straight body for stabilizing the airflow is not necessary, the distance from the mouth of the drum (front opening 7) to the product layer can be shortened, the workability is improved, and the device itself is downsized. The In addition, by using the chamber door 11 having a large projected area, the depth of the chamber door 11 itself can be suppressed, and a design in which the front opening 7 comes close immediately after opening the inspection door 15 is possible. Work becomes easy.

  Further, as shown in FIGS. 5 and 6, a spray gun 31 for spraying a coating liquid is inserted into the drum from the front opening 7 of the drum 1 on the front wall 2 a of the casing. The spray gun 31 is attached to a multi-function unit 32 disposed on the front surface of the casing 2 and is configured to be freely inserted into and removed from the drum from the front side of the apparatus. The multifunction unit 32 includes a support arm 35 that can move freely in an oblique 45 ° direction, and a support holder 33 to which a spray gun 31 is attached is attached to the support arm 35. A sugar gun coating spray gun 31a and a film coating spray gun 31b are attached to the support holder 33, and a single unit can handle a plurality of types of coating processes.

  In general, when the sugar coating treatment is performed, the sugar coating is often performed after undercoating by film coating. At that time, in the conventional coating apparatus, after film coating is performed, the spray gun is replaced for sugar coating, and there is a problem that time for parts replacement is required and time loss occurs. In that respect, in the coating apparatus 10, since the spray gun 31a for sugar coating and the spray gun 31b for film coating are attached to the multi-function unit 32, the sugar coating is continuously performed from the under coating without performing the replacement work. Can be implemented. For this reason, the man-hour required for the replacement work can be reduced, the work time can be shortened and the labor can be saved, the productivity can be improved, and the efficient coating process can be performed.

  As described above, the spray gun 31 is attached to the support holder 33, and the support holder 33 is connected to the support arm 35 through the hinge 34a so as to be relatively rotatable. A lock mechanism (not shown) is attached to the hinge 34a, and the hinge 34a portion can be arbitrarily set in a rotatable state and a non-rotatable state by a pin or the like (not shown). The support arm 35 is attached to the unit cover 36, and the lower end of the support arm 35 is opened as a connection port 35c at the lower end of the unit cover 36.

  The unit cover 36 is located on the left side of the front surface of the housing divided into three. When the unit cover 36 is closed, the multi-function unit 32 is disposed in front of the housing 2. In the multi-function unit 32, hoses for a spray gun are accommodated. In the coating apparatus 10, piping is not exposed on the front or side of the apparatus unlike the conventional apparatus, and the appearance of the apparatus is refreshed. It can be summarized in the form. A front cover 25 is also attached to the right side of the front surface of the housing, and the front surface of the housing 2 has a three-part configuration in which the monitoring window 14 is arranged in the center.

  The support holder 33 and the support arm 35 are formed of a hollow metal pipe (for example, a diameter of 50 mm), and a hose (not shown) for supplying a coating liquid and spray air to each spray gun 31 is provided inside thereof. Is housed. A maximum of five hoses (spray air, pattern air, cylinder air (needle valve), liquid (going), liquid (returning)) can be connected to one spray gun. It will be 15. For the same type of gun, the number of pipes can be reduced as appropriate by branching common pipes, using spray air and pattern air in common, or omitting liquid return pipes.

  The hose connected to the spray gun 31 is pulled out from the connection port 35c to the outside of the apparatus. That is, in the coating apparatus 10, the liquid hose and the air hose are concealed pipes, and these hoses are not exposed to the outside. For this reason, the contamination of the parts is reduced and the maintainability is improved, and the coating liquid and air are not easily affected by the temperature in the drum, thereby improving the coating quality.

  The unit cover 36 is attached to the housing 2 by a hinge 34b so as to be freely opened and closed. FIG. 8 is an explanatory diagram showing the operation of the multi-function unit 32, and FIG. 9 is an explanatory diagram showing the multi-function unit 32 as viewed from the front side. As shown in FIG. 8, in this embodiment, the multifunction unit 32 and the support holder 33 are a two-joint link mechanism connected by a hinge 34b. That is, in the coating apparatus 10, the spray gun 31 is installed in the drum 1 so as to be freely inserted and removed by appropriately bending the support arm 35 and the support holder 33 of the multifunction unit 32.

  In this case, if the support holder 33 and the support arm 35 are not bent and the spray gun 31 is moved in and out of the drum while the both are at right angles, the diameter of the front opening 7 must be increased, and the device More area for movement must be secured in front. On the other hand, in the coating apparatus 10, the spray gun 31 can be moved into and out of the drum while suppressing the radius of rotation by folding both of the support holder 33 and the support arm 35 so that the angle θ between the support holder 33 and the support arm 35 is small. Thus, the apparatus can be made compact.

  Further, as shown in FIG. 9, the multi-function unit 32 is arranged to be movable up and down in an oblique 45 ° direction (that is, a direction substantially perpendicular to the tablet flow surface), and the position of the spray gun in the drum is determined. It can be changed as appropriate. FIG. 10 is an explanatory diagram showing the configuration of the vertical movement mechanism of the multifunction unit 32. As shown in FIG. 10, the support arm 35 has a double tube structure, and the upper tube portion 35 a and the lower tube portion 35 b are connected within the unit cover 36. The upper pipe portion 35 a is slidably inserted into an arm guide 37 fixed to the unit cover 36, and is connected to an air cylinder 39 via a bracket 38. The lower pipe portion 35 b is fixed to the unit cover 36 with a bracket 40.

  When the air cylinder 39 is operated, the upper tube portion 35a moves along the axial direction, and the multifunction unit 32 moves about 150 mm between the lower position L and the upper position H shown in FIG. As a driving device for the upper pipe portion 35a, a hydraulic cylinder that is an actuator using the same fluid pressure may be used instead of the air cylinder 39. In addition, an electric motor can be used as the driving device.

  By the way, in the coating apparatus 10, as shown in FIG. 10, the multi-function unit 32 is configured to move at an angle of 45 °, but this is a multi-moving mechanism that can move in the vertical and horizontal directions, and the spray gun 31 is moved up and down (Y It may be possible to move to any position in the direction (vertical direction) and the left and right (X direction: horizontal direction). 11 to 13 are modifications of the multi-function unit using such a multi-moving mechanism. FIG. 11 is a front view of the manual multi-moving mechanism 41, FIG. 12 is a side view of FIG. 11, and FIG. It is a side view of the multi-moving mechanism 42 by. Note that. The multi-move mechanism 41 has a specification of being arranged on the right side of the front surface of the housing as shown by a one-dot chain line in FIG. 9, but it is of course possible to arrange it on the left side. 11 to 13, the support holder 33 is fixed to the support arm 35, and the spray gun 31 is inserted into the drum 1 and taken out from the drum 1 without bending both.

  The multi-moving mechanism 41 includes a vertical movement mechanism 41a and a horizontal movement mechanism 41b. As shown in FIGS. 11 and 12, the upper tube portion 35a of the support arm 35 is moved up and down by the bracket 43 on the vertical movement mechanism 41a side. Fixed to the moving base 44. A shaft holder 45, guide blocks 46 a and 46 b, and a nut block 47 are attached to the vertical movement base 44. One end of a guide rod 48 is fixed to the shaft holder 45, and the guide rod 48 is supported by guide blocks 46a and 46b so as to be movable in the axial direction. The other end side of the guide rod 48 is fixed to a shaft holder 51 attached to the left and right moving base 49.

  A screw rod 52 using a trapezoidal screw is screwed onto the nut block 47. One end side of the screw rod 52 is supported by a screw holder 53 attached to the left / right moving base 49 of the left / right moving mechanism 41b. Further, the other end side of the screw rod 52 is fixed to a screw holder 54 attached to the left and right moving base 49. One end of the screw rod 52 is connected to a vertical movement knob 56 via gears 55a and 55b. When the vertical movement knob 56 is rotated, the screw rod 52 is rotated via the gears 55a and 55b, and the nut block 47 is moved in the axial direction. Thereby, the vertical movement base 44 to which the nut block 47 is fixed moves up and down, and the upper pipe portion 35a moves up and down.

  A shaft holder 57, guide blocks 58 a and 58 b, and a nut block 59 are attached to the left and right moving base 49. One end of a guide rod 60 is fixed to the shaft holder 57, and the guide rod 60 is supported by guide blocks 58a and 58b so as to be movable in the axial direction. The other end side of the guide rod 60 is fixed to a shaft holder 62 attached to the unit base 61. The unit base 61 is fixed to the housing 2.

  A screw rod 63 using a trapezoidal screw is screwed onto the nut block 59. One end side of the screw rod 63 is fixed to a screw holder 64 attached to the left and right moving base 49. The other end of the screw rod 63 is fixed to a screw holder 65 attached to the unit base 61. One end side of the screw rod 63 is connected to a left and right movement knob 67 through gears 66a and 66b in the same manner as the vertical movement mechanism 41a. When the left / right moving knob 67 is rotated, the screw rod 63 is rotated via the gear, and the nut block 59 is moved in the axial direction. As a result, the left / right moving base 49 to which the nut block 59 is fixed moves to the left and right, and the upper tube portion 35a moves to the left and right. That is, the upper pipe portion 35a can be moved in any direction, up, down, left, and right by appropriately moving the vertical movement knob 56 and the horizontal movement knob 67.

  In this way, the multi-function unit 32 is configured to be freely movable in the horizontal direction and the vertical direction, so that the degree of freedom in adjusting the spray gun position can be expanded and the installation position of the spray gun 31 can be set in detail. It becomes. Therefore, it is possible to perform the coating process while always setting the spray gun at the optimum position, and the distance between the tablet surface and the spray gun 31 can be set as compared with the coating apparatus in which the spray gun can move only in one direction. Control that keeps constant can be easily and accurately executed. As a result, it is possible to continuously perform the coating process without stopping the apparatus, improving the coating process efficiency and reducing the production cost.

  Such an operation may be performed electrically. In the multi-moving mechanism 42, a vertical movement motor 68 and a left / right movement motor 69 are provided in place of the vertical movement knob 56 and the left / right movement knob 67. The multi-moving mechanism 42 is slightly different from the multi-moving mechanism 41 of FIGS. 11 and 12 due to the arrangement of the motors 68 and 69, but the basic mechanism and operation are the same as those of the multi-moving mechanism 41. The same members / parts are denoted by the same reference numerals, and detailed description thereof is omitted.

  An exhaust duct 71 for discharging air supplied to the drum 1 is also connected to the housing 2. In the housing 2, a seal duct 72 that is in sliding contact with the body 4 of the drum 1 and an upper duct 74 that is connected to the seal duct 72 and faces the exhaust port 73 are installed. The exhaust duct 71 is connected to the exhaust port 73, and the air supplied from the chamber door 11 is discharged from the drum 1 to the seal duct 72, and is discharged outside the apparatus through the upper duct 74 and the exhaust duct 71. .

  On the other hand, if the coating liquid or the like is sprayed into the drum 1 with the spray gun 31 and the exhaust is not performed at that time, the humidity in the drum becomes 100%, and a mist is drifted inside. At this time, in order to exhaust the excess humidity in the drum without affecting the coating process, the casing 2 is provided with a transpiration mist exhaust port 75 separately from the exhaust system. The transpiration mist exhaust port 75 opens to the internal space of the housing 2 and is connected to the exhaust duct 71.

  Further, when the transpiration mist is exhausted, the internal space of the housing 2 that is a sealed space becomes negative pressure, and therefore, a transpiration mist intake port 76 is provided to supplement the exhausted amount. A duct (not shown) that connects the internal space of the housing and the outside of the housing is attached to the intake port 76, and a damper that controls opening and closing of the duct is installed in the duct. When exhausting transpiration mist, the damper is opened to take in external air. Thereby, the inside of the drum 1 can be sucked weakly by the ventilation system thinner than the exhaust system, and the transpiration mist in the drum 1 is discharged out of the apparatus.

  The coating apparatus 10 is further provided with a spray nozzle 81 for cooling the drum in the housing 2. From the spray nozzle 81, a cooling medium such as humidified air containing fine mist is sprayed on the outer periphery of the drum 1, and the drum 1 is cooled by the heat of vaporization. Conventionally, it has been known to cool a drum without air vents with water spray, but spray cooling of a full punching drum used in a jacketless type coating apparatus wets the workpiece in the drum. It was supposed to cause quality problems. On the other hand, in this apparatus, by using very fine mist and considering the timing of spraying, the common sense is overturned, and spray cooling of the drum 1 having the air holes is made possible. For this reason, it was possible to cool the entire punching drum, which had been impossible in the past, and to improve the performance of the jacketless type apparatus.

  A plurality of spray nozzles 81 as described above are provided in the housing 2 and are disposed at positions where spraying is possible on both the body 4 and the conical part 5 (for body part: 81a, for conical part). 81b). The distance between the spray nozzle 81 and the drum 1 is set to about 200 mm to 250 mm, and the spread of the spray pattern (spray area) is 50 mm to 400 mm per spray nozzle 81 on the outer peripheral surface of the drum. Here, the diameter is preferably about 300 mm. The spray nozzle 81 is preferably attached at a position where the spray hits the body 4 from the tangential direction in order to suppress mist intrusion into the drum 1.

  As the spray nozzle 81, an internal mixing type two-fluid nozzle is used, from which a fine mist of coolant is sprayed onto the drum 1. Here, water (possible at room temperature) is used as the cooling liquid, and the spray nozzle 81 includes water and compressed air mixed in the nozzle, and includes a cooling mist (water mist) that is very fine water droplets. A cooling medium is generated. The average particle size of the cooling mist is preferably 5 μm to 100 μm. However, if it exceeds 50 μm, the evaporation of mist becomes somewhat slow, and the inside of the drum 1 becomes easy to get wet. Further, ultrafine mist such as so-called dry fog having an average particle diameter of 10 μm or less, preferably about 5 to 8 μm can be used. In this case as well, the spread of the spray pattern is set to a diameter of about 50 mm to 400 mm, preferably about 300 mm, per spray nozzle 81, but is preferably wider than the case of over 10 μm.

  That is, as the drum cooling method in the coating apparatus 10, various spray forms such as spraying with a fine mist of 10 μm to 100 μm by a normal two-fluid nozzle and spraying of dry fog of 10 μm or less can be appropriately employed. Note that the mist diameter may be different between the conical part 5 having no air holes and the perimeter punching body part 4, for example, the conical part 5 having no air permeability has a relatively large mist of more than 10 μm to 50 μm, the entire surface. You may make it spray ultra fine mist of 5-8 micrometers on the trunk | drum 4 of a punching structure.

  Such cooling mist is sprayed evenly from the spray nozzle 81 to the entire outside of the drum 1. Thereby, the drum section 4 and the conical section 5 of the drum 1 are cooled by the heat of vaporization of the attached cooling mist. At that time, since the sprayed cooling mist has a very small particle size, it quickly evaporates after adhering to the drum 1. For this reason, even if the cooling mist is sprayed onto the drum 1 having the air holes, the moisture is evaporated on the drum surface and hardly enters the inside, and the drum can be cooled in a dry environment.

  Next, the coating process using such a coating apparatus will be described taking the production of sugar-coated tablets as an example. Here, first, a tablet such as a lactose tablet (for example, a diameter of 8 mm, 200 mg / T) is put into the drum 1 as the workpiece 3 to be coated. In the coating apparatus 10, the workpiece 3 is introduced from the front opening 7 with the chamber door 11 opened. At this time, the front opening 7 comes close to the operator, so that workability is very good. Note that the multifunction unit 32 is moved out of the drum 1 when the workpiece is loaded. After charging a predetermined amount of the workpiece 3, the multi-function unit 32 is operated to set the spray gun 31 in the drum 1. Thereafter, the chamber door 11 is closed, the drum driving motor is operated, and the drum 1 is rotated.

  The coating liquid (sugar coating liquid) is sprayed from the spray gun 31 while the drum 1 is rotated on the workpiece 3 in the drum. The coating liquid contains a coating substance, a binder, a solvent, and the like, and is sprayed from the spray gun 31 at a predetermined pressure. FIG. 14A is an explanatory view showing a sugar coating treatment process in the coating apparatus, and FIG. 14B is a list showing presence / absence of supply / exhaust operation, transpiration mist operation, and mist cooling operation in each process of FIG. .

In the conventional coating process, normally, three steps of “spray” → “pause 1” (first pause step) → “drying” are usually repeated. Also, depending on the coating solution and other various conditions, “pause 2” (second pause process) is usually performed between “pause 1” and “drying” processes to form 4 processes. In this case, “spraying” is a process of spraying the coating liquid while rotating the drum 1 without performing air supply / exhaust (for example, about 8 rpm, hereinafter, description of numerical examples is omitted). “Pause 1” is a kneading process in which the drum 1 is rotated without supplying air and the coating liquid is spread on the tablet. “Pause 2” is a drum 1 rotated while only exhausting and dried. This is a process of reducing the humidity in the drum before the process, and spraying of the coating liquid is not performed in these pause 1 and 2 processes. Furthermore, “drying” is a process of supplying warm air to the drum 1 without spraying the coating liquid (70 ° C., 12 m ³ / min) to dry and solidify the coating liquid on the tablet.

  On the other hand, in the coating process in the apparatus, as shown in FIG. 14A, the cooling medium containing the cooling mist is sprayed from the spray nozzle 81 before the “spraying” process in the conventional processing process. A pre-cooling step for performing mist cooling is added. Further, the cooling mist spraying by the spray nozzle 81 is performed through three steps of “pre-cooling” → “spray” → “pause 1”. That is, as shown in FIGS. 14A and 14B, prior to “spray”, “pre-cooling” is performed (30 seconds) in which cooling mist spraying is performed without air supply and exhaust. Note that the processing contents in the steps of “spray”, “pose 1”, “pose 2”, and “dry” in FIG. 14A are the same as described above.

  Thereafter, “spray” (2 minutes) and “pause 1” (first pause step: 3.5 to 4 minutes) are performed while continuing the cooling mist spraying. The cooling mist spray may be appropriately terminated in the middle of “pause 1” depending on the processing status. In the spraying process (60 ° C., 340 to 900 mL / time), the sugar coating liquid is sprayed from the spray gun 31 onto the tablets. At that time, the position of the spray gun 31 is adjusted to an optimum position by the multi-function unit 32 according to the position of the tablet surface. As described above, since the spray gun 31 can move in an oblique 45 ° direction, the spray position with respect to the tablet flow surface is kept constant, and the coating conditions of the tablet can be adjusted to a constant or desired form. In particular, when the multi-moving mechanism 41 is employed, the spray gun 31 has a high degree of freedom of movement and can flexibly cope with various coating conditions.

  After the completion of “pose 1”, each process of “pose 2” (second pause process: 0.5 minute) and “dry” (4.5 minutes) is performed, as shown in FIG. This set is repeated a plurality of times (about 20 to 30 times) so as to return to “pre-cooling” after “drying”. At this time, if the spraying process is performed immediately after the drying process, the spraying is performed with the drum 1 being heated, and sugar coating residue is easily generated, which is not preferable as a coating environment. In this regard, in the coating process, “pre-cooling” is performed after the drying process, and the drum 1 is mist-cooled. Therefore, during the spraying process, the drum 1 is in a cold state, and problems such as sugar coating residue are less likely to occur. In addition, since the drum 1 is cooled in a short time, it is not necessary to wait for the drum 1 to cool, and the processing time is shortened.

  In the three steps of “pre-cooling” → “spray” → “pause 1”, the cooling mist continues to be sprayed on the drum 1, but very little moisture enters the drum 1 due to the fine mist. Further, after the “pose 1” step, a “drying” step is always performed. For this reason, the moisture content of the tablet in the process is not different from the conventional coating treatment, and in the experiments of the inventors, the moisture content of the tablet in the drying process and the moisture content of the final tablet are compared with the conventional method. We were able to maintain the same level. Furthermore, since the cooling mist is sprayed on the drum 1 in a process in which dry air (warm air) is not vented, the drum wall surface can be cooled in a short time and the cooling processing efficiency is high. In addition, when the mist is cooled, the baffle 26 together with the body 4 is also cooled by the cooling mist. For this reason, the heat radiation area increasing effect by the baffle 26 can be further enhanced, and the drum 1 can be efficiently cooled.

  Although it has been described that the amount of moisture entering the drum 1 by the cooling mist is very small, the moisture intrusion into the drum 1 is not completely zero as long as the mist is still sprayed. Further, since “exhaust” is performed in “drying”, the cooling mist easily enters the drum 1 due to the exhaust. Therefore, in the coating apparatus 10, for the sake of safety, even if the cooling mist enters the drum 1, the cooling mist spraying is performed in a process that hardly receives the influence. That is, the cooling mist spray is performed by “pre-cooling” in which the inside of the drum 1 will be wet, and “spray” and “pose 1” that are wet, and the mist is cooled in a wet environment. Thereby, the drum 1 can be cooled by the cooling mist without causing the entry of moisture into the drum.

  As described above, the coating apparatus 10 is an apparatus using a horizontal rotation type full-surface punching drum, but the outer periphery of the drum 1 with which the workpiece is in contact is directly cooled by the fine cooling mist. For this reason, solidification and adhesion of the sugar coating liquid to the inner surface of the drum can be suppressed, and defective products due to separation and adhesion of the solidified product can be reduced. Therefore, the occurrence of the botches of the sugar-coated tablets can be significantly reduced, and the inventors' experiments have been able to suppress the occurrence of the botches almost completely. Moreover, since the horizontal rotation type drum is used, damage to the raw material tablets can be suppressed, and in this respect as well, the defective product generation rate can be reduced.

  Furthermore, since the sugar coating residue is prevented from adhering to the inner surface of the drum, the number of cleanings inside the drum can be reduced, and the processing efficiency and the number of work steps can be improved. As a result, the spread of a jacketless type coating apparatus having a simple structure and easy maintenance can be promoted.

  Such a series of steps is repeated to finish spraying a predetermined amount of the coating liquid, and finish the coating process when a desired coating layer is formed on the object to be processed. During the coating process, it is possible to appropriately observe the processing status from the monitoring window 14. When the coating process is completed, the chamber door 11 is opened, the multifunction unit 32 is moved out of the drum 1, and a product discharge cylinder (not shown) is incorporated in the drum 1. Thereafter, the chamber door 11 is closed again, and the product discharge port 17 is opened while the drum 1 is rotated to discharge the coated product.

  It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

  For example, the various numerical values described above are merely examples, and it goes without saying that the values can be changed as appropriate. In addition, the object to be treated in the present invention is not limited to tablets such as the above-mentioned lactose tablets, and foods such as confectionery and gum, other pharmaceuticals, and the like are also applicable. In addition to the syrup obtained by dissolving sugar in water, sugar coating liquids of various specifications such as those obtained by adding various medicinal ingredients, flavors, pigments and the like can be applied.

  In the coating apparatus 10 described above, the chamber door 11 is opened to the right due to the control panel 82 provided on the left side of the front surface of the apparatus. However, it is of course possible to adopt a left-open structure. It is also possible to arrange the multifunction unit 32 on the front right side. Furthermore, although the front surface of the housing 2 is divided into three parts and the central part is the chamber door 11, the left and right unit covers 36 and the front cover 25 are communicated with the chamber door 11, and the chamber door 11 is When closed, the entire front surface of the housing may be the air supply chamber 13. As a result, the projected area and the internal volume of the air supply chamber 13 can be further increased.

  In addition, a cleaning nozzle may be further incorporated in the multi-function unit 32 of the coating apparatus 10, whereby the steps from coating to cleaning can be performed continuously. As shown in FIGS. 5 and 6, in the coating apparatus 10, the spray gun 31 is arranged on one side of the support holder 33 (in the upper left direction in FIG. 6), but the spray gun 31 is on the other side. It can also be disposed (in the diagonally downward right direction in FIG. 6 symmetrically with the spray gun 31). At that time, the installation direction of the spray gun 31 may be changed according to the application, such as sugar coating for one side and film coating for the other side.

  It is also possible to adopt a reduction system that incorporates vibration means into the multi-function unit 32 and shakes down the workpiece placed on the support holder 33 during processing. Furthermore, a scattering preventing member such as a net may be attached to the front opening 7 so that the object to be processed does not jump out from the front opening 7 of the drum 1 into the chamber door 11. At this time, a current plate may be used as the scattering prevention member to further stabilize the supply air.

It is a right view which shows the structure of the pan coating apparatus which is one Example of this invention. It is a front view of the pan coating apparatus of FIG. It is a top view (top view) of the pan coating apparatus of FIG. (A) is a side view of a rotating drum, (b) is explanatory drawing which shows the structure of the three-dimensional ventilation baffle installed in the rotating drum. It is a top view which shows the state which opened the chamber door. It is a front view of the state which opened the chamber door. (A) is a front view of a wind direction board, (b) is the sectional drawing. It is explanatory drawing which shows operation | movement of a multifunction unit. It is explanatory drawing which shows the state which looked at the multifunction unit from the front side. It is explanatory drawing which shows the structure of the vertical movement mechanism of a multifunction unit. It is a front view of a manual multi-move mechanism. It is a side view of the multi-moving mechanism of FIG. It is a side view of the multi move mechanism by a motor drive. (A) is explanatory drawing which shows the sugar-coating process process in the said coating apparatus, (b) is a table | surface which shows the presence or absence of the air supply / exhaust operation, transpiration mist operation, and mist cooling operation in each process of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating drum 2 Housing | casing 2a Front wall 2b Upper surface 3 To-be-processed object 4 Body part 5 Conical part 6 Vent hole 7 Front opening 8 End plate 9 Rotating shaft 10 Pan coating apparatus 11 Chamber door 12 Hinge 13 Supply chamber 13a Supply air Chamber front wall 14 Monitoring window 15 Inspection door 16 Grip bar 17 Product discharge port 18 Air supply hole 19 Air supply duct 21 Air supply port 22 Airflow direction plate 23 Frame body 24 Louver 25 Front cover 26 Baffle 27 Vent hole 28 Baffle mounting hole 29 Drum chamber 30 Sink 31 Spray gun 31a Spray gun 31b for sugar coating 31 Spray gun for film coating 32 Multi-function unit 33 Support holder 34a Hinge 34b Hinge 35 Support arm 35a Upper pipe part 35b Lower pipe part 35c Connection port 36 Unit cover 37 Arm Guide 38 Bracket 39 Air cylinder 40 Bracket 41 Multi-moving mechanism 41a Vertical movement mechanism 41b Horizontal movement mechanism 42 Multi-movement mechanism 43 Bracket 44 Vertical movement base 45 Shaft holder 46a, 46b Guide block 47 Nut block 48 Guide rod 49 Left-right movement base 51 Shaft Holder 52 Screw rod 53 Screw holder 54 Screw holder 55a, 55b Gear 56 Vertical movement knob 57 Shaft holder 58a, 58b Guide block 59 Nut block 60 Guide rod 61 Unit base 62 Shaft holder 63 Screw rod 64 Screw holder 65 Screw holder 66a, 66b Gear 67 Left / right movement knob 68 Vertical motion motor 69 Left / right motion motor 71 Exhaust duct 72 Seal duct 73 Exhaust port 74 Upper duct 75 Transpiration mist exhaust 76 transpiration mist intake port 81 spray nozzle 81a barrel spray nozzle 81b conical section spray nozzles 82 control panel H upper position L lower position O rotation axis θ angle

Claims (8)

A pan coating apparatus provided with a rotary drum that is provided to be rotatable about a substantially horizontal rotation axis and has a vent hole in at least a part of an outer peripheral portion thereof, and a housing that houses the rotary drum,
A pan coating apparatus having a drum cooling means installed in the housing and spraying a cooling medium containing fine cooling mist on the outside of the rotating drum.   2. The pan coating apparatus according to claim 1, wherein the cooling mist is a fine water droplet having an average particle diameter of 5 μm to 100 μm.   3. The pan coating apparatus according to claim 1, wherein the cooling medium is sprayed by a spray nozzle installed outside the rotating drum, and a spray area of the cooling medium on an outer peripheral portion of the rotating drum is per one spray nozzle. A pan coating apparatus having a diameter of 50 mm to 400 mm. A rotary drum that is provided to be rotatable about a substantially horizontal rotation axis and has a vent hole in at least a part of an outer peripheral portion thereof, a housing that houses the rotating drum, a housing that is installed in the housing, In a pan coating apparatus comprising a drum cooling means for spraying a cooling medium containing fine cooling mist on the outside, a coating liquid is supplied into the rotating drum to coat the object to be processed in the rotating drum A pan coating method for performing
A pre-cooling step of spraying the cooling medium to the outside of the rotating drum without supplying and exhausting the rotating drum;
A spraying step of spraying the coating liquid onto the object to be processed while rotating the rotating drum without supplying and exhausting the rotating drum;
A pause step of rotating the rotating drum without supplying and exhausting the rotating drum;
And a drying step of rotating the rotary drum while supplying and exhausting the rotary drum.   5. The pan coating method according to claim 4, wherein the cooling medium is sprayed to the outside of the rotating drum in the spraying step in addition to the precooling step.   5. The pan coating method according to claim 4, wherein the cooling medium is sprayed to the outside of the rotating drum in the spraying step and the pause step in addition to the precooling step.   7. The pan coating method according to claim 4, wherein the cooling mist is fine water droplets having an average particle diameter of 5 μm to 100 μm.   The pan coating method according to any one of claims 4 to 7, wherein a spray area of the cooling medium in an outer peripheral portion of the rotating drum has a diameter of 50 mm to 400 mm per drum cooling means. Pan coating method.

Images