Device for coating particles

Translation of description of equivalent WO 0137980 A2

Apparatus for coating particles

The invention relates to a device for coating particles according to the preamble of the main claim.

From European Patent EP 0570546 Bl such a fluidized bed reactor is known and it is used to coat particles or small lozenges that circulate in a container by means of a bottom-up air or gas (eg nitrogen), the particles are passed through a vertically upward jet of a liquid coating material. With the circulation of the particle through the beam, a small amount of coating material respectively deposited on the surface of the particles, wherein the number of revolutions of the particles determines the layer thickness. Such a coating apparatus according to the prior art functions satisfactorily, if the particles are fine and light. However, if the particles are larger, as for example, tablets or the like, it has been found that the coating becomes uneven because the heavier tablets do not circulate uniformly through the container. The coating apparatus according to the prior art can not be used for applications are to requiring a uniform, predictable layer thickness of all tablets in a batch. In addition, there is a risk that the tablets because of the high speeds in circulating abut obstacles and be damaged. Since the active ingredients are dosed accurately into the tablet, it is not acceptable that the tablets due to damage and abrasion loss of value of the active ingredient.

The invention is therefore based on the object to provide an apparatus for coating particles, the large particles with different geometric shapes, which may also have rough edges, are for example, tablets, coated in a gentle way and with an even layer thickness, the want to keep dimensional stability of the particles or tablets.

This object is achieved by the characterizing features of the main claim in conjunction with the features of the preamble.

Characterized in that means for the support gas supply are provided in the vicinity of the perforated inflow base, which in one NEN support gas stream with at least one laterally directed from outside to inside flow component Direction of the gap to form a gas overlay and / or that means for constructive forming the bottom of the container are located, which form a transition channel between the returning zone and the coating zone with substantially constant limiting surfaces, the particles, ie the tablets out in a directional particle flow, and there is a bouncing tablets at obstacles largely avoided, whereby the pockets bletten be transported in a gentle manner, so that no damage occurs. It can also particles with lower mechanical stability and such are coated with rough edges. Due to the means for constructive molding, ie by inserted into the lower region internals, a transition duct into the coating zone adjoins the recirculation zone of quasi wherein the boundary surfaces of this transition duct at least partially from the peripheral surfaces of the means of constructive molding together with the inflow and the boundary walls of the container, but can also be formed by the gas overlay, which is supplied from the supplied auxiliary gas stream.

Furthermore -both avoided by means of constructive molding as well as by the flow of gas delivered by the means for supporting gas supply so-called dead zones at which tablets could receive so that a uniform circulation of the tablet through the coating zone and thus on the tablets of batch uniform coating is ensured.

By measures indicated in the dependent claims, advantageous developments and improvements are possible. It is particularly advantageous that around the spray nozzle, a ramp-shaped body is arranged, which is perforated and on the one hand part of the means for constructive forming of the lower portion of the container to the transition duct and on the other hand is part of the means for the support gas supply. Through the perforation of the ramp-shaped body by the supplied air in this area, process a vertical supporting air is formed so that the tablets in the transition duct of the ramp-shaped circumferential surface are guided along as on an air cushion. There is prevented the direct impingement of the tablets on the shaft of the spray nozzle.

Preferably, the means direct to the supporting gas supplying the supporting gas flow with a laterally directed flow component at the lower end of the container adjacent to the inflow one, thereby forming a horizontal supporting air is formed (in the case of air as the gas), which prevents the tablets in inadequately from below at zero incidence areas lie of the inflow, and to simultaneously also ensure that the tablets are transported via the distributor plate as on an air overlay from the outside inward to coat zone. Additionally, it is advantageous that the region in which the inflow openings are mounted at the same time slightly inclined or cone-shaped or arc-shaped as a ring, whereby an adapted

Transition created by the inclination of the container wall towards the inflow to the drain, the tablet more easily and are thereby transported well from the outside inwards. The supply for the hori- zontal supporting air can take place by external air or conducted in the bypass part process air gen, where appropriate, a more flexible process control is given by the possibility of regulating the amount of air temperature and pressure in the first case, while in the second case, advantageously no additional monitoring of the resulting product quality through homogeneous purity of the main and sub-process stream, the common be produced and processed, is necessary.

In an advantageous manner is provided at the lower end of the

Riser an approach or an "apron" arranged, whose peripheral surface is inclined in the direction of flow of the tablet. In his the inflow region facing the approach the circumferential surface horizontally or in the direction of the coating zone is inclined or arcuate. Thus, the flow direction of the tablets is adapted in the recirculation zone so that they move easily and guided towards the coating zone and that there is not one nem backwater in the recirculation zone or on the outer edge of the inflow. This is also achieved by the cross-sectional constriction results in the recirculation zone to an increase in the gas velocity, which in turn over the upper region of the recirculation zone may lead to a partial relaxation of the recirculation zone, whereby the tablets can be oriented in the direction of flow better, and these are the more easily transported in particular through the gap between inflow and riser. In the arcuate configuration of the peripheral surface or at a drop-shaped cross-section results in terms of flow, a venturi effect similar to the coating zone.

It is also advantageous if the gas flowing through the inflow into the container process gas for coating Administrative Region and is supplied to the recirculation zone in separate Teilanströmkanälen since the respectively supplied process gas then set differently, can be monitored and regulated.

The fact that a discharge channel connected to a discharge opening is provided for discharging the coated tablets in the inflow, which is covered by a movable closure member, the tablets may be removed from the container in a simple and gentle manner.

Embodiments of the invention are shown in the drawing and are explained in the following description of letters. Show it:

Fig. 1 shows a section through an embodiment of the device according to the invention,

Fig. 2 is an enlarged view of a portion of the

Device according to Fig. 1,

Fig. 3 is a plan view of the device for supporting the gas supply,

Fig. 4 is a section through the device for supporting the gas supply,

Fig. 5 shows a section through the nozzle casing,

Fig. 6 is a view of a ramp body,

Fig. 7 is a plan view of the ramp body,

Fig. 8 is a section through a first embodiment of the neck, Fig. 9 shows a section through a second embodiment of the neck,

Fig. 10 is a view of a further embodiment of the coating apparatus according to the invention,

FIG. 11 is a sectional view of still another example of the coating apparatus of the invention,

Fig. 12 is a bottom view corresponding to FIG. 11,

Fig. 13 is a discharge device in a first position,

Fig. 14 is a discharge device in a second position.

In Fig. 1 is a section through an embodiment of the device for coating particles, for example, of tablets. The apparatus for coating 10 comprises a container 12 with conical peripheral walls 72, the bottom of which is formed by a serving as inflow 14 well plate. In the container 12 a substantially cylindrical support tube is centered 24 with -distance to the distributor plate 14, wherein a spray nozzle 18 which passes through a central opening 20 of the inflow 14 is directed into the interior of the support tube 24 and an implied spray 32 coating material is sprayed. The inflow 14 is gas-tightly connected to an inflow channel 16 for supplying process gas 15th Designed as a perforated plate distributor plate 14 has a plurality of holes 30 which are arranged such that the process gas 15, which may be for example air, nitrogen or the like can flow from the purchase flow channel 16 through the holes 30 into the product container 12 to produce a fluidized bed, as will be described later.

In the container to be coated particles or tablets 27 are arranged, extending through an opening formed in the interior of the support tube 24 and coating zone 33 move a formed between support tube 24 and wall 72 of the container 12 return zone 37th Preferably, the porosity of the designed as a perforated plate formed inflow base 14 respectively to the coating zone 33 and matched the return zone 37, ie, the number, arrangement and size of the holes 30 are chosen and arranged such that in the coating zone 33, a large volume of gas from the inflow channel 16 into the container, ie into the support tube 24 at relatively high speed, and in the region of the return zone 37, a sufficient flow of gas is supplied in order to keep the particles 27 in such a loosened or flowable state that the particles due to gravity move as individually against the process air in the direction of the inflow base down and can not agglomerate.

For coating the particles or tablets 27 are disposed in the container and it is supplied to filtered process air or process gas 15 via blower or compressed gas sources not shown, typically there is a negative pressure in the container 12 and in one ner subsequent expansion chamber, so that process air 15 drawn through the inflow becomes. This flowing both into the coating zone and the recirculation zone process air fluidizes the particles 27, and it is the sweeping through the central opening 20 spray nozzle 18 is activated to spray one NEN controlled spray 32 into the support tube 24th In this case, the coating material at high speed and under pressure, the amount of the type and size of the particles to be coated, is dependent on 27 the type of coating material and the desired coating properties, injected. In the coating zone 33, the particles 27 rise at a high speed, which is given by the process gas stream and through the spray, in the support tube 24 high, and they come with the Zerstäubungströpfchen the Beschichtungsflüssig- speed in contact and be coated before the end the support tube 24 are forced into the flash zone as indicated by arrow 35 radially outward. Once they come out of the influence of directed GE upward gas flow, the particles or tablets 27 to fall by gravity into the recirculation zone 37 downwards, they formed the basis of the differential pressure between the coating zone 33 and recirculation zone 37 in the bottom of the container "transition zone" be retracted into the coating zone 33rd In this manner, the particles or tablets 27 circulate several times through the coating zone 33 and the return zone 37, which is coated in the upward movement and dried and in the downward movement of the coating material is dried to an end.

In order to channel the flow of particles between the return zone 37 and the coating zone 33, means are provided for constructive forming of the lower portion of the container 12 and / or means for supplying support gas provided individually or jointly form a transition channel between recirculation zone 37 and coating zone 33 with substantially continuous boundary surfaces, the boundary surfaces can also be realized by gas overlays in no physical way. As shown in FIG. 1, consisting of the means to design molding and the means for supplying the supporting gas from a shoulder 120 and on the lower end of the support tube 24, from a nozzle ramp 22 and a gas supply means 50 which of the lower peripheral is the container 12 is provided. Further measures to line the ring-transition channel between recirculation zone 37 and coating zone 33 are feasible.

In the following, said means for molding and structural support for the supply of gas will be described in more detail. As seen from FIGS. 3 is to recognize and 4, the gas supply means 50 includes a ring-shaped gas channel 62 which is formed by a distributor plate 14 arranged on the sealing ring 68 and a downwardly open channel ring 66th Channel ring 66 and Bodenabdichtring 68 are overlapped by an outer ring 70 and the entire assembly is supported on the gas distributor plate 14 from and surrounds the lower part of the container 12 and is part of the boundary wall of the container 12. For this purpose, the outer ring 70 with a circumferential groove 58 provided on the inner circumference, the lower end of the sawn container wall 72 engages in this peripheral 58th As can be seen from Fig. 4 and Fig. 1, the inner leg 52 of the channel ring 66 is obliquely formed so that an extension of the container wall 72 is provided without jumps. The bottom at the lower end of the inner leg are openings 60 through the periphery, preferably one another at equal intervals are arranged, which are directed radially inwardly. A supply tube 64 communicates with the annular channel 62 in connection, so that under pressure 64 supplied gas or air supplied evenly flows radially through the supply pipe via the plurality of openings 60 to the inside, which is indicated in Fig. 3 by the arrows 65th The ring assembly shown in FIG. 4 can be taken apart in a simple manner, to permit cleaning.

In FIG. 2, the ring assembly of FIG. 3 and 4, shown in more detail in the installed condition, wherein it can be seen that a radially inwardly directed gas stream is blown 65 via the openings 60 into the container, whereby dead zones are avoided because all tablets 27, which are provided in the transition region between the container wall 72 and inflow 14, inward to the spray nozzle 18 toward and for coating zone 33 are forced out. In this case can the volume and velocity of the gas, which is injected via the openings 60, ER controlled according to the conditions of the tablets and the changes in the flow properties of the tablets due to the different phases of the coating. Due to the gas-inflow via the openings

60 a gas overlay is formed, which is horizontally inward and the lower tablets the recirculation zone 37 are indicated by the arrow 65 to move radially inwards to make room for other tablets to make 27 of the recirculation zone. Here, the horizontally inwardly directed air flow cooperates with the light passing through the openings 30 of the inflow process gas stream.

In FIG. 2, directed into the interior of the container surface of the leg 52 is formed obliquely. Even- of course it can also be arcuate in order to ensure a smooth transition to the inflow.

The openings 60 of the circumferential flow channel 62 are formed as round holes in Fig. 3 and 4, they may also be slot-shaped or it may also be a circumferential slot may be provided.

The gas supply through the supply pipe 64 is independent of the supply of process gas 15 through the inflow passage 16, whereby a good adjustability of the flow parameter is given in accordance with the process parameters. However, it is also possible to support the gas flow via the supply means 50 to branch off from the process gas.

In Fig. 1 to be recognized nozzle ramp 22 is closer shown in FIGS. 2, 5, 6, 7 is shown. The nozzle ramp 22 prevents the 33 from the return zone 37 inwardly sucked tablets 27 are represented by the existing horizontal component of movement, especially for heavy and large tablets abut against the nozzle and damaged due to the strong negative pressure in the area of ​​the coating zone. Accordingly, FIGS. 5 to 7 is the nozzle ramp of a nozzle casing 90 and a perforated body 102. shown in Fig. 6 and 7 shown in FIG. 5, the nozzle casing 90 is hollow and includes an chen essentially cylindrical base portion 92 and a tapered upper portion 96. The spray nozzle 18 passes through the center of nozzle casing, wherein between nozzle 18 and nozzle casing remains a distance such that 14 flowing process gas is passed through the interior of the nozzle casing 90 through the openings 30 of the inflow. The upper end of Düsenman- means 90 may be so shaped that the emerging therefrom gas contributes to formation of the spray 32nd In another embodiment, the upper end be formed so that the nozzle 18 is sealingly received, so that no gas or only a small amount passes through the nozzle casing 90th

The perforated body 102 according to FIGS. 6 and 7, shows an arcuate peripheral surface 114 as a ramp surface, similar to a hat on, said the inflow base 14 facing surface has a larger diameter than the support tube 24 facing upper surface. Further, the hole body 102 is provided with a cylindrical through hole 108th

As shown in FIG. 1, the nozzles ramp 22 is arranged centrally on the distributor plate 14 wherein a steady transition area between inflow and peripheral surface 114 of the perforated body 102 is formed. The perforated body 102 surrounds the nozzle casing 90, which is received in the central through hole 108, such that the ramp-like peripheral surface 114 of the perforated body 102 continues substantially by the conical circumferential surface of the upper part 96 of the nozzle jacket 90th Of course, also an integral part consisting of perforated body and nozzle casing, be provided, it is conceivable that the lower part 92 of the nozzle jacket 90 is left path.

The perforated body 102 has a plurality of vertically arranged through-holes 116, which are preferably arranged as shown in FIG. 7 in concentric rings gene. The through holes 116 preferably have such dimensions that they can with the corresponding openings 30 of the form of a perforated plate inflow base 14 can be oriented so that the air flowing through the openings 30 from the inflow channel process gas 15 released by the geared ended through holes of the nozzle ramp 22 can flow through and at the upper end of each through hole 116 along the arcuate ramp surface 114 may emerge at different heights. The through holes 116 may be equal to or greater than its corresponding openings 30 of the onflow tray 14, whereby the process gas flow can be controlled in the through holes 116th

The purpose of the nozzle ramp 22 is to align the process gas from the inflow channel 16 along a curved arcuate ramp surface 114, so that the fast-moving, horizontally driven tablets to be 27 deflected by the air cushion formed or air overlay formed in the vertical direction. The use of the nozzle ramp 22 minimizes undesired triggering of the tablet 27 against an obstacle, since they are directed according to the arrow 118 in FIG. 2 in continuous movements in the coating zone back.

Optionally, the nozzles 22 be formed ramp that not through holes 116 are provided in a form of the body, but that the nozzle ramp as a whole is designed to be hollow, and only through-are-holes punched in its scope.

The in the recirculation zone 37 that are available tablets 27 move as a rate of one meter in 10 to 30 seconds down. When these tablets are 27 drawn into the coating zone, they are an example to approximately 5 to 10 meters per second speeds, this relatively sudden speed a large transition burden on the relatively low stability of tablets containing 27 exerts in the prior art. To reduce these stresses is shown in FIG. 1 on or at the lower end of the support tube 24, a neck 120, through which the loads exerted on the tablets by the sudden changes is reduced. In the FIG. 1 exemplary embodiment illustrated the approach 120 is designed as an annular cone 130 having an inclined at an angle A to the vertical peripheral surface 122. This is more particularly shown in Fig. 8. The cone 130 is provided with an inner cylindrical bore 124 to receive the lower end of the support tube 24 to which it is attached.

In the embodiment of FIG. 8, the approach 120 of two elements, the cone 130 and attached to the cone ring 130 is 128. The bottom, the distributor plate 14 facing surface 126 of the extension 120 and the ring 128 is preferably in accordance with angle B inclined inwards, in order to accelerate that are available in the vicinity tablets 27th Here, the outer edge 132 of the ring 128 is rounded. The angle B is selected depending on the size, shape and weight of the tablets 27 and the dimensions of the container and the coating properties and other sizes. The divided form of the approach different rings may be 128 provided with different inclinations of the surface 126 corresponding to different requirements. Of course, can also be formed as an integral part of the approach.

In Fig. 9 is another embodiment for one NEN approach 120 shown, in which the lower end of the support tube 24 is inserted. This approach has an approximately drop-shaped cross-section, ie, the tapered surface 122 extends in an arc towards the coating zone and the coating zone 33 facing inner surface of the through hole 124 is slightly inclined at an angle C. Characterized a venturi-like effect is achieved. The predetermined by the arc at the lower end of the teardrop-shaped approach angle (tangent to the peripheral surface) are chosen according to the operating variables and parameters. The A in FIGS. 8 and 9 designated angle may be between 1 ° and 50 °, preferably 10 ° to 35 °, while angle C is between 1 ° and 15 °.

The in the return zone 37, especially near the neck 120 that are available tablets 27 are obliquely deflected by the inclined surface 122, until they reach the arcuate 127 or lower surface 126 and are accelerated due to the pressure difference. The arcuate peripheral surface 127 as shown in FIG. 9 and the inclined surface 122 as shown in FIG. 8 contribute to a more uniform acceleration so that the loads are kept low on the tablets. The peripheral surfaces also form part of the continuous boundary surfaces of the transition duct 22 formed by the projection 120, the inclined container wall 72, optionally, an arc-shaped or the inclined inner wall of the leg 52 of the support gas supply device and the distributor plate 14 and the nozzle ramp. The is located under the approach 120 tablets 27 are easily lifted by the by the inflow 14 strömen- de process gas, since there is less downward force exerted on it than in the upper region reaching the recirculation zone 37. The result is that the tablets are easier and stress-poorer led by the return zone 37 through the transition duct into the coating zone 33rd

In Fig. 10, a further embodiment of the apparatus for coating tablets is shown which in contrast to FIG. 1 having a modified arrangement of the process gas supply. is know how to achieved, the inflow channel is divided into two sub-channels, a central channel 170 and an outer annular duct 172. The central channel 170 is used to supply the process gas in the coating zone 33, ie, it is mounted on the gas distributor plate 14 in the region of the nozzle senrampe 22 arranged. The central channel 170 is connected to a suitable gas source (pressure gas source or blower) and comprises a measuring device 174 for measuring the velocity, the pressure, the gas volume, the humidity and / or the temperature of the guided into the coating zone 33 the process gas. The measuring device is connected to the gas source, not shown, can be achieved so that a gas stream having suitable flow characteristics and maintained using known control devices.

Similarly, the outer ring channel 172, the process gas for controlling the fluidized bed properties of the recirculation zone 37 in the region is the same feeds, to a gas source (not shown), wherein also a measuring device 176 measures the parameters mentioned above. Regardless can be adjusted via a, likewise not shown, and control system of the gas stream supplied.

In FIGS. 11 and 12 is another embodiment example shown, three support tubes 24 are arranged in which to increase the efficiency in a container 12, a plurality in the embodiment. The support tubes are each within the container provided at the same distance, with a higher number of support tubes can be selected. In the coating apparatus 142 of Fig. 11 is by way of example, an embodiment of the support tube 24 is shown with a flared trumpet-shaped end 145, which can of course be used also in the previously described embodiments. Optionally, the widening may also earlier, ie in smaller height of the support tube 24, begin. The in Figs. 1 described elements to 10 are also provided in this coating device 142, but the clarity not executed due here.

In Fig. 11 and 12 an improved discharge device is provided which allows a gentle and contamination-free dispensing. In the prior art, the inflow channel 16 is usually folded down together with the distributor plate 14 and the total charge is poured into a container. Here again, the tablets may be damaged, and in addition, the effluent process gases are not always without problems. There is also the risk of contamination of the process environment and the operators due to dust, and abrasion of the product. Therefore, the invention is a closed discharge system provided accordingly.

The discharge device has a discharge channel 144 that extends from the center of the inflow base 146 to a remote location. The inflow 146 is similar to the above-described inflow bottom 14, comprises with the exception that it is designed for three nozzles 18, which are arranged at an angle of 120 ° to each other and, therefore, three large passage openings for the nozzles. The Anströmbo- the 146 includes a central discharge opening 150, in which the discharge channel 144 is taken up, as more specifically shown in Figs. is illustrated. 13 and 14 A tapered duct cover 152 is movable above the gas distributor plate 146 in alignment with the center discharge opening 150 disposed off. The tapered duct cover 152 is arranged with the tip up and moved between two positions, a sealed position as shown in FIG. 13 and an open position as shown in FIG. 14 generating device An actuation 154 is connected to the cover 152 and moves them between the two positions.

If the channel cover 152 is closed, remain- ben the tablets 27 in the container and can be coated in the manner described above, as indicated by the arrows 155th The conical cover 152 serves as a dividing element, which distributes the tablets 27 of the common return zone to the three supporting tubes 24th

If the coating process is completed, the actuator 154 is activated, whereby the cover 152 vertically rises upward and a gap 156 between the periphery of the discharge port 150 and the periphery of the cover 152 is formed. Thus, the tablets may be sucked into the discharge channel 144, as indicated by the arrows 158 in FIG. 14, if it continues processing device in the coating 142 to circulate between the coating zone and recirculation zone. The tablets are pre- preferably sucked by using a pressure difference between the container 12 and the discharge channel into the latter. In the embodiment, the discharge opening is disposed in the middle, of course, they may also be provided elsewhere, particularly in other arrangements of the coating apparatus.

The discharge channel 144 can also serve in cleaning the coating device for discharging larger remaining particles. For example, can be injected by the means for supplying supporting gas, ie set on the supporting gas supply device 50 into the container cleaning fluid under high pressure, which larger particles are forced into the center of the device and can be discharged via the discharge channel 144th