Dryer for herbal materials having a channel shape collector

Abstract

A rotary dryer comprises a dryer receiving portion having an internal space for receiving herbal material, a driving device for rotating the dryer receiving portion around a rotation axis of the dryer receiving portion, and a channel-shaped collector having at least a partially open upper portion and provided in the internal space of the dryer receiving portion for collecting dried herbal material.

Description

Technology Field

[0001] The present invention relates to the drying of herbal materials, particularly tobacco materials. Background Technology

[0002] CN 202 760 152 U discloses a drum-shaped dryer for crushed tobacco material for use in the tobacco industry. Heated air is introduced into the drying chamber of the dryer to heat the tobacco material inside. It is noted that the oxygen content of the air inside the dryer has a significant effect on the chemical composition of the dried tobacco. The oxygen content is controlled by implementing an oxygen / nitrogen separation system to automatically adjust the oxygen content in the gas supplied to the dryer. To prevent ambient air from entering the dryer in an uncontrolled manner, airlock devices are provided at the tobacco inlet and tobacco outlet of the dryer.

[0003] CN 101 491 368 A discloses a rotary drum drying device for cut tobacco. The drying device comprises a fixed outer drum and a rotary inner drum provided therein. A heating rod is provided within the gap between the circumferential surfaces of the inner drum and the outer drum. Additionally, the circumferential surface of the inner drum has a double wall forming a space for receiving heating oil to be heated by the heating rod. When the heating oil is heated, the inner circumferential surface of the inner drum is heated, and heat is transferred to the tobacco material provided inside the inner drum. A blade for engaging the crushed tobacco material extends radially from the inner circumferential surface of the inner drum toward the center of the inner drum. When the inner drum rotates, the blade agitates the crushed tobacco provided inside the inner drum.

[0004] It is desirable to provide a drying process having a high level of accuracy and controllability. In addition, it is desirable to provide a method for drying herbal materials to produce high-quality dried material. It is even more desirable to provide a method for drying herbal materials with improved efficiency.

[0005] The present invention deals with the processing of herbal materials. In particular, the herbal material may consist of or include tobacco materials, such as cut, ground, or crushed tobacco materials, or a combination of cut, ground, or crushed tobacco materials. The herbal material may be used, for example, as a sensory medium material in smoking articles.

[0006] The present invention provides a rotary dryer for drying herbal materials. The dryer comprises a dryer housing having an internal space for receiving herbal materials and a driving device for rotating the dryer housing around a rotation axis of the dryer housing.

[0007] The dryer further includes a channel-shaped collector provided within the internal space of the dryer housing to collect dried herbal material. The upper portion of the channel-shaped collector is at least partially open. This means that the collector has an opening oriented to allow herbal material falling from above due to gravity to enter the collector. The shape of the collector with an open upper portion allows the dried herbal material to easily enter the collector, while simultaneously restricting or controlling the collected material from escaping the collector back into the dryer housing. Additionally, the collector has a simple configuration and is economical to implement.

[0008] The characteristics and quality of dried herbal materials obtained by the drying process strongly depend on the drying process. For example, sensory media materials, such as tobacco materials used in the smoking industry, can exhibit a wide range of aromas and characteristics depending on the sequence and parameters of the drying process. Therefore, by improving the collection of herbal materials within the internal space of the dryer's receiving section, the quality of the obtained product can be improved.

[0009] Preferably, the internal space of the dryer housing is symmetric with respect to the rotational axis of the dryer housing. The body of the dryer housing may extend along the longitudinal direction from a first side of the body to a second side of the body. The first side of the body may include a first end of the body. The second side of the body may include a second end of the body. The longitudinal direction may be particularly parallel to and coaxial with the rotational axis of the dryer housing. In particular, the dryer housing or its body may be at least substantially cylindrical. However, other shapes such as a parallelepiped, a prism, or an ellipse may also be conceivable. In practice, the shape of the dryer housing or its body will not strictly correspond to the indicated shape. For example, the dryer housing or its body may include a conveyor or a recess.

[0010] A first side of the main body may be a side into which a herbal substance is introduced into a dryer receiving portion. A second side of the main body may be a side into which a herbal substance is withdrawn from a dryer receiving portion.

[0011] The dryer housing may include a first door provided on a first side of the main body. The dryer housing may include a second door provided on a second side of the main body. The door may be opened to access the internal space of the dryer housing for maintenance, loading, or other purposes.

[0012] The dryer housing may have a longitudinal length of at least 1 m, or at least 1.5 m, or at least 2 m, or at least 2.5 m. The longitudinal length of the dryer housing may be less than 10 m, or less than 5 m, or less than 3 m, or less than 2 m. The extension of the dryer housing in a direction perpendicular to the longitudinal direction may be at least 0.5 m, or at least 0.7 m, or at least 1 m, or at least 1.5 m. The extension of the dryer housing in a direction perpendicular to the longitudinal direction may be less than 5 m, or less than 3 m, or less than 2 m, or less than 1.5 m. The capacity of the dryer housing is at least 0.5 m 3 , or at least 1m 3 , or at least 1.5m 3 , or at least 2m 3 , or at least 3m 3 It may be. The capacity of the dryer receiving section is 10m 3 Less than, or 7m 3 Less than, or 5m 3 Less than, or 3m 3 Less than, or 2m 3 It may be less than

[0013] The driving device may be configured to rotate the dryer housing at, for example, 0.2 rpm to 30 rpm, or 5 rpm to 20 rpm. In particular, the rotation rpm of the dryer housing may be adjustable by the user.

[0014] Preferably, the rotary dryer further includes a tilting device for adjusting the tilt angle of the dryer receiving portion with respect to a horizontal plane. The tilt angle of the dryer receiving portion can be defined as the tilt angle between the rotation axis of the dryer receiving portion and the horizontal plane. The tilt angle can be adjusted to optimize the delivery and distribution of the herbal material within the dryer receiving portion. The tilt angle can be used to set the residence time of the herbal material within the dryer receiving portion. The tilt angle can be adjusted, for example, in terms of the particle size of the herbal material. The tilt angle can be adjusted, for example, from 0 to 15 degrees, or from 0 to 10 degrees. The tilt angle can also be changed periodically, such as by oscillating motion, between two or more predetermined values.

[0015] The residence time of the herbal material in the receiving portion of the dryer may be, for example, 1 minute to 4 hours, or 30 minutes to 4 hours, or 1 hour to 3 hours. In particular, the residence time may substantially be 2 hours.

[0016] If the herbal material to be dried contains different types of materials, the different types of materials may be supplied sequentially into the dryer receiving section to have different residence times within the dryer receiving section for the different types of materials. The different types of materials may contain biologically or chemically different types of materials. The different types of materials may contain materials that differ from each other in their particle size. The different types of materials may contain materials that differ from each other in their cutting width, or in their leaf size, or in their powder size.

[0017] The driving device can be configured to change the rotational direction of the dryer receiving section. By changing the rotational direction of the dryer receiving section, the herbal material within the dryer receiving section can undergo momentum and move within the dryer receiving section even if it is blocked. Changing the rotational direction of the dryer receiving section can improve the distribution of the herbal material within the dryer receiving section.

[0018] The dryer can be operated in batch drying mode or continuous drying mode.

[0019] Preferably, the channel-shaped collector extends at least substantially parallel to the rotation axis of the dryer receiving portion. In particular, the rotation axis of the dryer receiving portion may extend within the channel-shaped collector. The dryer receiving portion may rotate around the channel-shaped collector and may be configured so that herbal material falls down by gravity and enters the channel-shaped collector through at least a partially open upper portion.

[0020] A channel-shaped collector can be positioned at the end of the dryer housing with respect to the extension direction of the rotation axis. According to this embodiment, it becomes easy to provide the channel-shaped collector in the internal space of the dryer housing. Additionally, it becomes easy to remove the herbal material collected within the collector. In particular, the channel-shaped collector can be provided at the access opening or door of the dryer housing.

[0021] Preferably, the channel-shaped collector is stationary while the dryer receiving portion rotates. This ensures that the opening of the channel-shaped collector is always oriented toward the upper surface. Herbal material can be collected within the collector by gravity.

[0022] The dryer may further include an outlet conveyor configured to remove dried herbal material collected in the channel-shaped collector from the internal space of the dryer receiving portion. Preferably, the outlet conveyor can remove the dried herbal material during the rotation of the dryer receiving portion. The outlet conveyor can enable a continuous operation mode of the dryer.

[0023] The conveyor may include a chute for supplying herbal material into the internal space of the dryer receiving section. Preferably, the outlet conveyor includes a conveyor screw, scraper, or spiral extending within the channel-shaped collector and out of the dryer receiving section. The conveyor screw, scraper, or spiral may engage directly with the herbal material collected in the channel-shaped collector.

[0024] The rotary dryer may further include a nozzle for spraying a fluid provided at the end of a conveyor screw reaching into the internal space of the dryer housing. Preferably, the nozzle reaches into the internal space of the dryer housing via a channel-shaped collector. The nozzle may be used, for example, to spray a liquid for processing or purifying herbal materials during drying. The nozzle may also be used to spray a cleaning liquid to clean the interior of the dryer housing between uses. The nozzle may be rotatable and may spray the liquid into places inside the dryer housing that are difficult to reach, for example, within the corners or edges of the internal space of the dryer housing. In particular, the nozzle may distribute the sprayed liquid uniformly in the circumferential direction, axial direction, or both circumferentially and axially.

[0025] According to one embodiment, the channel-shaped collector is asymmetric with respect to a plane defined by the rotation axis and vertical direction of the dryer receiving portion. Due to the asymmetry of the collector, the entry of herbal material into the collector can be facilitated while the dryer receiving portion rotates. Additionally, due to the asymmetry, the collector can prevent the herbal material from leaving the collector and returning into the internal space of the dryer receiving portion.

[0026] The cross-section of the channel-shaped collector may have two sections extending in different directions. Preferably, the two sections generally extend in an upward direction. In particular, the distance between the two sections may increase in the upward direction. This allows the collector to have a relatively large extension in its open upper portion so that herbal material can easily enter the collector. The opening angle defined by the two sections may be at least 30 degrees, or at least 40 degrees, or at least 45 degrees, or at least 50 degrees, or at least 60 degrees, or at least 70 degrees, or at least 80 degrees, or at least 90 degrees, or at least 100 degrees, or at least 110 degrees. The opening angle defined by the two sections may be less than 160 degrees, or less than 140 degrees, or less than 130 degrees, or less than 120 degrees, or less than 110 degrees, or less than 100 degrees, or less than 90 degrees, or less than 80 degrees, or less than 70 degrees, or less than 60 degrees, or less than 50 degrees.

[0027] Preferably, one section is shorter than the other section. In particular, the length of the shorter section may be at least 20% of the length of the longer section, or at least 30% of the length of the longer section, or at least 40% of the length of the longer section, or at least 50% of the length of the longer section, or at least 60% of the length of the longer section, or at least 70% of the length of the longer section. The length of the shorter section may be less than 90% of the length of the longer section, or less than 80% of the length of the longer section, or less than 70% of the length of the longer section, or less than 60% of the length of the longer section, or less than 50% of the length of the longer section, or less than 40% of the length of the longer section.

[0028] According to one embodiment, the channel-shaped collector includes a central section in addition to two sections. The two sections may extend from the opposite end of the central section as lateral sections. A curved or angled connecting section may connect the central section and the lateral section. The central section and the lateral section may be substantially flat or curved. In particular, the distance between the lateral sections may increase in the direction away from the central section, particularly in the upward direction. This causes the collector to have a relatively large extension in its open upper portion so that herbal material can easily enter the collector. Then, the herbal material that has entered the upper portion is funnel-shaped toward the central section, where it can be picked up, for example, by a conveyor screw.

[0029] In particular, the cross-section of the channel shape collector may be at least substantially U-shaped or substantially V-shaped. A U-shaped shape means a shape having a straight or curved base section and two essentially parallel arms extending from the opposing ends of the base section. A V-shaped shape means a shape having two arms connected to each other at the first ends of the arms, and the arms extend linearly away from the first ends such that the distance between the arms increases with the distance from the first ends of the arms. The channel shape collector may also be U / V-shaped. A U / V-shaped shape means a shape having a straight or curved base section and two arms extending from the opposing ends of the base section, and the distance between the arms increases as the distance from the base section increases.

[0030] Preferably, the dimensions of the channel-shaped collector in a direction perpendicular to the rotation axis of the dryer receiving portion are smaller than half, less than one-third, or less than one-fourth of the dimensions of the internal space of the dryer receiving portion in a direction perpendicular to the rotation axis. This ensures that there is sufficient space within the dryer receiving portion for the herbal material to move around without being obstructed by the collector, thereby ensuring high drying efficiency.

[0031] A rotary dryer may include a collector heating element configured to heat a channel-shaped collector. Heating the collector can remove residual moisture before the herbal material leaves the internal space of the dryer's receiving section. In particular, the collector heating element may include, for example, an electric resistance heating element. The electric resistance heating element allows for direct, rapid, and precise control of the heating power. Alternatively, the collector heating element may include a heating fluid line through which a heating fluid flows. Heating by the heating fluid line provides improved heat transfer and simplified control over the heating temperature. For example, hot oil, steam, superheated steam, water, or pressurized water may be used as the heating fluid. The collector heating element may also include a radiation heating element.

[0032] The present invention also provides a method for drying a herbal substance. The method comprises the steps of: rotating a dryer receiving portion that receives the herbal substance around a rotation axis; and collecting the herbal substance dried within the dryer receiving portion into a collector comprising a plate that partially surrounds the rotation axis. The collector has a simple structure and is easy to manufacture. Nevertheless, the plate that partially surrounds the rotation axis enables the drying herbal substance to be efficiently collected and removed from the dryer receiving portion. The collector enables the material to be removed from the center of the dryer receiving portion.

[0033] Preferably, the collector is decoupled from the rotation of the dryer receiving portion. This ensures that the plate surrounds the rotation axis so that the opening is oriented upward, thereby allowing the herbal material to enter the collector and fall into the plate to be collected by gravity.

[0034] The above method may further include the step of transporting the dried herbal material collected in the collector out of the dryer receiving section. Preferably, this is accomplished by using a conveyor screw suitable for efficiently picking up the collected herbal material within a plate that partially surrounds the rotation axis. The herbal material may be removed from the dryer receiving section during the rotation of the dryer receiving section or while the dryer receiving section is not rotating.

[0035] According to one embodiment, the method further comprises the step of treating a volatile substance evaporated in a dryer receiving portion. The volatile substance may include a substance evaporated from a herbal substance during drying. Such volatile substances may, for example, carry flavors extracted from the herbal substance. The volatile substance to be treated may, for example, include an aromatic substance or an oil. The volatile substance may, for example, include an alkaloid such as nicotine. The volatile substance may also be, for example, 2-methylpyrazine; 2,5-dimethylpyrazine; 2,6-dimethylpyrazine; 2-ethylpyrazine; 2,3-dimethylpyrazine; 2-ethyl-5-methylpyrazine; 2-ethyl-6-methylpyrazine; 2,3,5-trimethylpyrazine; tetramethylpyrazine; 2-ethyl-3,6-dimethylpyrazine; Or it may include pyrazines such as 2-ethyl-3,5-dimethylpyrazine. Other examples of volatile substances include β-ionone; β-damashinone; or acetic acid.

[0036] According to one embodiment, current environmental characteristics may be used to determine one or more drying process parameters. Examples of drying process parameters are the rpm of the dryer housing, the temperature profile within the internal space of the dryer housing, the processing time of the herbal material, or the angle of inclination. Environmental characteristics may include, for example, characteristics of the herbal material to be dried.

[0037] Additionally or alternatively, the environmental characteristics of the previous drying operation can be used to determine one or more process parameters.

[0038] In particular, machine learning can be used to determine one or more drying process parameters based on current environmental characteristics, environmental characteristics of previous drying operations, and data collected during previous drying operations.

[0039] The present invention also provides the use of a curved plate for collecting herbal material during the drying process of herbal material in a rotary dryer receiving section.

[0040] The present invention further provides a rotary dryer for drying herbal materials as described below. The features of the dryer may be combined with any one of the aforementioned dryer, method, or use. The dryer comprises a dryer housing having an internal space for receiving the herbal material and a driving device for rotating the dryer housing around its rotation axis.

[0041] A vane for engaging the herbal material contained in the internal space of the dryer receiving portion extends from the inner surface of the dryer receiving portion into the internal space of the dryer receiving portion. The inner surface may at least partially define the internal space of the dryer receiving portion. In particular, the inner surface may be the circumferential surface of the dryer receiving portion. When the dryer receiving portion rotates, the vane can engage with and agitate the herbal material. Thus, heat within the dryer receiving portion can easily reach the herbal material. Due to the vane, the herbal material can be heated uniformly. The vane can contribute to the uniform distribution of the herbal material within the dryer receiving portion.

[0042] In a cross-section having a cross section perpendicular to the rotation axis of the dryer receiving portion, the vane is inclined with respect to the radial direction. The radial direction is perpendicular to the rotation axis and radial to the rotation axis of the dryer receiving portion. The inclination of the vane allows the vane to better engage and agitate the herbal material within the internal space of the dryer receiving portion. In particular, the vane can easily immerse itself in the herbal material located at the bottom of the internal space of the dryer receiving portion during rotation of the dryer receiving portion, thereby picking up the herbal material. Geometrically, the inclined vane can scoop up the herbal material from its surface and maintain contact for a longer period than a radial vane. The inclined vane can form a pocket together with the internal surface of the dryer receiving portion, which allows the herbal material to be temporarily retained during rotation of the dryer receiving portion, thereby increasing the agitation and distribution of the herbal material within the dryer receiving portion.

[0043] The characteristics and quality of dried herbal materials obtained by the drying process are strongly dependent on the drying process. For example, sensory media materials, such as tobacco materials used in the smoking industry, can exhibit a wide range of aromas and characteristics depending on the sequence and parameters of the drying process. Therefore, the quality of the obtained product can be improved by enhancing the stirring or heating of the herbal materials.

[0044] In a cross section having a cross section perpendicular to the axis of rotation, the angle between the vane and the radial direction is preferably lower than 30 degrees. In particular, the angle may be 5 to 25 degrees or more preferably 5 to 15 degrees. The indicated range may be suitable for temporarily holding the herbal material within the pocket formed by the vane and the inner surface of the dryer receiving portion while still allowing the herbal material to be easily picked up by the vane.

[0045] In principle, any number of vanes may be provided within the dryer receiving section. Preferably, there are at least 4, at least 6, at least 8, at least 10, or at least 16 vanes. A larger number of vanes increases the stirring of the herbal material within the dryer receiving section, provided there is still sufficient space between adjacent vanes. Preferably, there are fewer than 32, fewer than 28, fewer than 24, fewer than 20, fewer than 16, fewer than 12, or fewer than 8 vanes.

[0046] According to one embodiment, the vane has a parallelepiped shape. Such a vane is easy to manufacture and arrange within the dryer housing. However, other shapes of the vane can also be imagined. In particular, the vane may have curvature in a cross-section perpendicular to the axis of rotation. Curved vanes can better engage and pick up herbal materials. Preferably, the curvature of the vane is curvature in the direction of the vane's inclination. This can increase the rotation period of the dryer housing while the herbal material is held on the vane.

[0047] According to one embodiment, the vane may extend along the inner surface of the dryer receiving portion parallel to the rotational axis of the dryer receiving portion. The herbal material may be uniformly stirred along the longitudinal extension of the dryer receiving portion.

[0048] Alternatively, the vane may extend along the inner surface of the dryer housing in a path that is an overlapping portion of an extension parallel to the axis of rotation and a rotational portion around the axis of rotation. This “twisted” extension of the vane may contribute to the delivery of herbal material parallel to the axis of rotation of the dryer housing.

[0049] Preferably, the arch distance between two adjacent vanes with respect to the axis of rotation is equal to or greater than the height dimension of the vanes. This ensures that adjacent vanes interfere less with the vanes picking up herbal material, and allows for the optimization of the amount of engaged material per rotation of the dryer receiving section. The term " arch distance It is not required that the inner surface of the dryer housing between adjacent vanes have curvature along the arch. For example, the inner surface may be flat between two adjacent vanes. The arch distance may be defined as the length of a section line of a portion of the inner surface of the dryer housing between two adjacent vanes having a plane perpendicular to the axis of rotation of the dryer housing. The height dimension of the vane may be defined as the length of a line connecting the center point of the radially outer base portion of the vane at the interface between the inner surface of the dryer housing and the vane to the center point of the radially inner far end of the vane in a cross section having a cross section perpendicular to the axis of rotation.

[0050] For example, the height dimension of the vane may be at least 10 cm, or at least 15 cm, or at least 20 cm, or at least 25 cm, or at least 30 cm, or at least 40 cm, or at least 50 cm. The height dimension of the vane may be less than 50 cm, or less than 40 cm, or less than 30 cm, or less than 20 cm, or less than 10 cm. The arch distance may be at least 10 cm, or at least 15 cm, or at least 20 cm, or at least 25 cm, or at least 30 cm, or at least 40 cm, or at least 50 cm. The arch distance may be less than 1 m, or less than 70 cm, or less than 50 cm, or less than 40 cm, or less than 30 cm, or less than 20 cm. The height dimension of the vane may be, for example, at least 5% of the inner diameter of the dryer receiving portion, or at least 7% of the inner diameter of the dryer receiving portion, or at least 10% of the inner diameter of the dryer receiving portion, or at least 12% of the inner diameter of the dryer receiving portion, or at least 15% of the inner diameter of the dryer receiving portion, or at least 17% of the inner diameter of the dryer receiving portion. The height dimension of the vane may be, for example, less than 25% of the inner diameter of the dryer receiving portion, or less than 22% of the inner diameter of the dryer receiving portion, or less than 20% of the inner diameter of the dryer receiving portion, or less than 17% of the inner diameter of the dryer receiving portion, or less than 15% of the inner diameter of the dryer receiving portion.

[0051] The rotary dryer preferably further includes vane heating elements integrated within the vanes to heat the herbal material. The vane heating elements can contribute to drying the herbal material. Heating the vanes with the heating elements integrated within the vanes works in conjunction with the inclination of the vanes with respect to the radial direction. As previously mentioned, due to the inclination of the vanes, the herbal material is held by the vanes for an increased fraction of rotation of the dryer receiving section. Thus, the herbal material receives heat from the heating elements integrated within the vanes for an increased duration.

[0052] The rotary dryer may further comprise a liquid dispersion assembly comprising at least one nozzle assembly rotatably provided within the internal space of the dryer housing and configured to spray a liquid. The nozzle may be used, for example, to spray a liquid for processing or purifying herbal materials during drying. The nozzle may also be used to spray a cleaning liquid to clean the interior of the dryer housing between uses. Since the nozzle can be rotated, the nozzle may spray a liquid into places that are difficult to reach inside the dryer housing, for example, into a pocket formed between the vane and the internal surface of the dryer housing.

[0053] The rotary dryer may further include a conveyor for supplying herbal material into the internal space of the dryer receiving section. The conveyor may include a chute for supplying the herbal material into the internal space of the dryer receiving section. The conveyor may include a conveyor screw, a scraper, or a spiral for supplying the herbal material into the internal space of the dryer receiving section.

[0054] The present invention further provides a method for drying a herbal substance as described below. The features of the method may be combined with any one of the aforementioned dryer, method, or use. The method comprises the step of introducing the herbal substance into the internal space of a dryer receiving part having a vane extending from the internal surface of the dryer receiving part into the internal space of the dryer receiving part. The dryer receiving part having the herbal substance contained therein is rotated in a rotational direction around the rotation axis of the dryer receiving part. During rotation, the herbal substance contained within the dryer receiving part engages with the engaging surface of the vane. This agitates the herbal substance within the dryer receiving part and facilitates drying. The vane is arranged such that, in a cross-section perpendicular to the rotation axis of the dryer receiving part, the angle between the vane and the internal surface of the dryer receiving part is greater when measured in the rotational direction of the dryer receiving part than when measured in the rotational direction of the dryer receiving part. Since the angle is smaller when measured with respect to the rotational direction of the dryer housing, the vanes are arranged to engage more easily with the herbal material collected from the bottom of the dryer housing during rotation, thereby collecting material between the vanes and the inner surface of the dryer housing.

[0055] The above method may further include the step of temporarily capturing a herbal material between the interlocking surface of the vane and the inner surface of the dryer receiving portion during the rotation of the dryer receiving portion. Preferably, the herbal material is captured between the interlocking surface of the vane and the inner surface of the dryer receiving portion during at least 1 / 4 rotation, or at least 1 / 3 rotation, or at least 1 / 2 rotation, or exceeding 1 / 2 rotation of the dryer receiving portion.

[0056] The above method may further include the step of actively heating the vane using a vane heating element preferably integrated into the vane.

[0057] The present invention also provides the use of an asymmetric structure on the inner surface of a rotary dryer receiving portion for receiving a herbal material to influence the distribution of the herbal material during the rotation of the dryer receiving portion. The asymmetric structure may be particularly asymmetric with respect to the rotation axis of the dryer receiving portion. The use of the asymmetric structure can improve the stirring of the herbal material within the dryer receiving portion. Additionally, the use of the asymmetric structure can improve the heat distribution to the herbal material. Due to the use of the asymmetric structure, drying efficiency and quality can be improved.

[0058] In particular, the asymmetric structure can be asymmetric with respect to the radial direction.

[0059] The present invention further provides a dryer for drying herbal materials as described below. The features of the dryer may be combined with any one of the aforementioned dryer, method, or use. The dryer comprises a dryer receiving portion having an internal space for receiving the herbal material, an access assembly providing access to the internal space of the dryer receiving portion, and a heating system.

[0060] The access assembly may provide access to the internal space of the dryer receiving for introducing a herbal material into the dryer receiving or extracting a herbal material from the dryer receiving. The access assembly may provide access to the internal space of the dryer receiving for introducing or extracting any other material that is processed together with the herbal material. The access assembly may provide access to the internal space of the dryer receiving for introducing or extracting any other material used to process the herbal material within the dryer receiving. The access assembly may provide access to the internal space of the dryer receiving, for example, for maintenance and related purposes.

[0061] The heating system includes at least one approach heating element for actively heating the approach assembly. Preferably, at least one approach heating element is integrated into the approach assembly. Heating the approach assembly can prevent or reduce the formation of a lower temperature spot in the approach assembly.

[0062] The low temperature point can cause condensation of gaseous substances within the dryer assembly, such as water, aromatic substances, oils, or volatile substances extracted from herbal materials during drying.

[0063] Condensation of gaseous substances within the dryer's receiving section can negatively affect drying efficiency. Condensation of gaseous substances within the dryer's receiving section can also negatively affect the chemical composition and quality of the dried product. In particular, herbal materials to be dried may stick together and clump at low temperatures due to humidity. Condensation at low temperatures can also cause cleaning activity. Specifically, caramelization that is difficult to remove may occur at the condensation points within the dryer's receiving section.

[0064] In addition, heating the access assembly can facilitate maintaining a desired temperature within the dryer housing. Heating the access assembly can facilitate obtaining a desired temperature profile within the dryer housing. Heating the access assembly can facilitate optimizing drying efficiency and quality. The desired temperature profile may be a uniform temperature, for example, across the entire dryer housing, such as 20°C to 200°C, 100°C to 200°C, 100°C to 150°C, or 120°C to 150°C. Due to convective or conductive heat loss, this may require uniform heating. The desired temperature profile may also be a non-constant temperature profile, for example, a time-dependent or moisture-dependent temperature profile.

[0065] The characteristics and quality of dried herbal materials obtained through a drying process are strongly dependent on the drying process. For example, sensory media materials, such as tobacco materials used in the smoking industry, can exhibit a wide range of aromas and characteristics depending on the sequence and parameters of the drying process. Therefore, the quality of the obtained product can be improved by enhancing the heating of the herbal materials or preventing low-temperature points.

[0066] According to one embodiment, the access assembly includes a door provided in the dryer housing, and at least one access heating element includes a door heating element integrated into the door. The door may be opened to access the internal space of the dryer housing for maintenance, loading, or other purposes. The inner surface of the door may be part of the inner surface of the dryer housing. Thus, heating the door may contribute to controlling the temperature of the inner surface of the dryer housing.

[0067] The access assembly may include at least one of an inlet conveyor for supplying herbal material into the internal space of the dryer receiving section and an outlet conveyor for removing herbal material from the internal space of the dryer receiving section. At least one access heating element may include a conveyor heating element (inlet conveyor or outlet conveyor, or both) integrated into the conveyor. Heating the inlet conveyor or the outlet conveyor can prevent the formation of a low-temperature point in each conveyor. Additionally, if the inlet conveyor is heated, the herbal material is preheated on the inlet conveyor before actually entering the internal space of the dryer receiving section. This can prevent or reduce a temperature drop within the internal space of the dryer receiving section when new herbal material is introduced, or ensure a uniform temperature of all herbal material within the dryer immediately after introduction into the dryer receiving section. If the outlet conveyor is heated, the herbal material can be finally heated on the outlet conveyor to remove residual moisture.

[0068] At least one approach heating element may include, for example, an electric resistance heating element. The electric resistance heating element allows for direct, rapid, and precise control of the heating power. Alternatively, at least one approach heating element may include a heating fluid line through which a heating fluid flows. Heating by the heating fluid line provides improved heat transfer and simplified control over the heating temperature. For example, hot oil, steam, superheated steam, water, or pressurized water may be used as the heating fluid. At least one approach heating element may also include a radiation heating element. Another example of an approach heating element is an annular furnace.

[0069] Preferably, a temperature sensor for determining the access assembly temperature is provided. The access assembly temperature may be, in particular, the temperature of the access assembly or the temperature at the access assembly. The access assembly temperature may be the temperature of the door of the dryer receiving section or the temperature at the door of the dryer receiving section. The access assembly temperature may be the temperature of the inlet conveyor for supplying the herbal material to the internal space of the dryer receiving section or the temperature at the inlet conveyor for supplying the herbal material to the internal space of the dryer receiving section. The access assembly temperature may be the temperature of the outlet conveyor for removing the herbal material from the internal space of the dryer receiving section, or the temperature at the outlet conveyor for removing the herbal material from the internal space of the dryer receiving section. The access assembly temperature determined by the temperature sensor may be used to control at least one access heating element.

[0070] According to one embodiment, the dryer further includes a controller configured to control at least one access heating element to maintain at least a predetermined minimum access assembly temperature. The controller may control at least one access heating element based on the access assembly temperature provided by a temperature sensor or a plurality of temperature sensors. The minimum access assembly temperature may be selected according to a specific drying process. For example, the minimum access assembly temperature may be 15°C to 250°C, or 20°C to 200°C, or 100°C to 200°C, or 100°C to 150°C, or 120°C to 150°C.

[0071] The heating system may further include at least one wall heating element contained within the wall surface of the dryer housing. In particular, the at least one wall heating element may be integrated into the circumferential wall surface of the dryer housing or the wall surface of the main body of the dryer housing.

[0072] The heating system may further include a vane heating element for actively heating at least one vane extending from the inner surface of the dryer receiving portion into the inner space of the dryer receiving portion.

[0073] At least one wall heating element or at least one vane heating element or both may include an electric resistance heating element, a heating fluid line through which a heating fluid flows, a radiation heating element, or an annular furnace.

[0074] Heating the wall of the dryer receiving portion or at least one vane of the dryer receiving portion, or both, enables maintaining or achieving a desired temperature in the dryer receiving portion. For example, the temperature within the dryer receiving portion may be in the range of 15°C to 250°C, or 20°C to 200°C, or 100°C to 200°C, or 100°C to 150°C, or 120°C to 150°C.

[0075] According to a preferred embodiment, at least one approach heating element comprises a plurality of approach heating elements arranged to be controlled independently. Independent control of different approach heating elements enables the setting of different heating zones according to a desired temperature profile or temperature distribution to optimize drying. For example, the temperature may be higher or lower at the inlet side of the dryer receiving where the herbal material enters the dryer receiving than at the outlet side of the dryer receiving where the herbal material exits the dryer receiving. Alternatively or additionally, the temperature in the intermediate region of the dryer receiving between the inlet side and the outlet side may be higher or lower than the temperature at the inlet side or the outlet side.

[0076] The present invention further provides a method for drying a herbal substance as described below. The features of the method may be combined with any one of the aforementioned dryer, method, or use. The method comprises the step of heating the herbal substance in the internal space of the dryer receiving section. During the heating of the herbal substance, the internal surface of the dryer receiving section is heated so that the entire internal surface of the dryer receiving section is maintained above the condensation temperature of the gas evaporated inside the dryer receiving section. The condensation temperature may be at least 20°C, or at least 30°C, or at least 50°C, or at least 80°C, or at least 120°C. The entire internal surface of the dryer receiving section defining the internal space of the dryer receiving section may be heated so that it is completely maintained above the condensation temperature. This prevents condensation of the gaseous substance inside the dryer receiving section during heating. Condensation can have a negative effect on the drying efficiency and quality of the dried product. The gas evaporated inside the dryer receiving section during the heating of the herbal substance may be a gas extracted from the herbal substance during the heating of the herbal substance. Examples of gases evaporated inside the dryer's receiving section during the heating of herbal materials are water, aromatic substances, oils, and volatile substances extracted from the herbal materials during drying.

[0077] In particular, the inner surface of the dryer receiving portion can be heated to 15°C to 250°C, or 20°C to 200°C, or 100°C to 200°C, or 100°C to 150°C, or 120°C to 150°C.

[0078] The above method may further include the step of actively heating an inlet conveyor for supplying a herbal material to the internal space of the dryer receiving section above at least the condensation temperature. The above method may further include the step of actively heating an outlet conveyor for removing the herbal material from the internal space of the dryer receiving section above at least the condensation temperature. Heating the inlet conveyor is preferably achieved by a conveyor heating element integrated into the inlet conveyor. Heating the outlet conveyor is preferably achieved by a conveyor heating element integrated into the outlet conveyor. Preferably, the inlet conveyor or the outlet conveyor, or both the inlet conveyor and the outlet conveyor, are heated to be maintained above the condensation temperature.

[0079] The above method may further include the step of actively heating at least one door of the dryer receiving portion by a door heating element preferably integrated into the door.

[0080] According to one embodiment, the first door and the second door of the dryer housing provided on opposite sides of the dryer housing are actively heated to different temperatures. Different temperature zones may be established in the dryer housing to optimize the drying process.

[0081] The present invention also provides for the use of an access heating element for actively heating an access assembly that provides access to the internal space of a dryer receiving portion for receiving a herbal material, thereby preventing the formation of a low point where gaseous material generated during the drying of the herbal material can condense.

[0082] The present invention further provides a dryer for drying a herbal substance as described below. The features of the dryer may be combined with any one of the aforementioned dryer, method, or use. The dryer comprises a dryer housing having an internal space for receiving the herbal substance, a heating system for heating the herbal substance, and a controller configured to control the heating system.

[0083] The heating system includes heating subsystems. The controller is configured to control the heating subsystems independently of one another. Independent control of the heating subsystems allows heating to be adjusted according to specific requirements for specific areas of the dryer. For example, different temperature zones may be set to optimize the drying process of herbal materials. However, within the scope of the present invention, it is also possible to have different control characteristics for different heating subsystems without having separate temperature zones. For example, at least one or more heating subsystems may have feedback control parameters different from other heating subsystems. Thus, at least one or more heating subsystems may respond faster or slower to deviations from the temperature target value with more or less heating power. Independent control of the heating subsystems provides a high level of adjustability for the drying process.

[0084] The characteristics and quality of dried herbal materials obtained by the drying process are strongly dependent on the drying process. For example, sensory media materials, such as tobacco materials used in the smoking industry, can exhibit a wide range of aromas and characteristics depending on the sequence and parameters of the drying process. Independent control of the heating subsystem allows for a significant influence on the quality of the dried material.

[0085] Preferably, each heating subsystem includes at least one heating element. The at least one heating element may include, in particular, at least one resistance heating element. An electric resistance heating element allows for direct, rapid, and precise control of the heating power. Alternatively or additionally, at least one heating element may include a heating fluid line through which a heating fluid flows. Heating by the heating fluid line provides improved heat transfer and simplified control over the heating temperature. Additionally, constant control over the heating temperature may be provided. For example, hot oil, steam, superheated steam, water, or pressurized water may be used as the heating fluid. At least one heating element may also include a radiation heating element. Another example of an access heating element is an annular furnace.

[0086] The heating subsystem may include one or more body heating subsystems for heating the body of the dryer housing. Preferably, at least two, at least three, at least four, at least five, or more than five body heating subsystems are provided for heating distinct sections of the body of the dryer housing. This allows the heating of different sections of the body of the dryer housing to be controlled independently. According to one embodiment, different temperature sections having different temperatures are established along the longitudinal extension direction of the dryer housing. For example, a higher temperature zone may be established near the inlet for supplying herbal material into the internal space of the dryer housing so that moisture of the relatively wet herbal material entering the dryer housing evaporates. For example, a higher temperature zone may be provided at the outlet where the herbal material leaves the dryer housing so that residual moisture in the herbal material is removed.

[0087] Each body heating subsystem may include a wall heating element integrated into the wall surface of the body of the dryer housing. Additionally or alternatively, each body heating subsystem may include a vane heating element integrated into a vane extending from the inner surface of the dryer housing into the internal space of the dryer housing.

[0088] The heating subsystem may include one or more access heating subsystems integrated into an access assembly that provides access to the internal space of the dryer housing. Heating the access assembly can, for example, prevent or reduce the formation of cold spots within the access assembly. Cold spots can lead to the condensation of gaseous substances within the dryer assembly, such as water, aromatic substances, oils, or volatile substances extracted from herbal materials during drying. Condensation of gaseous substances within the dryer housing can negatively affect drying efficiency. Condensation of gaseous substances within the dryer housing can negatively affect the chemical composition and quality of the dried product. In particular, herbal materials to be dried may stick together and clump at cold spots due to humidity. Condensation at cold spots can also cause cleaning activity. Additionally, heating the access assembly can facilitate maintaining a desired temperature within the dryer housing. Heating the access assembly can facilitate obtaining a desired temperature profile within the dryer housing. Heating the access assembly can facilitate optimizing drying efficiency and quality. The desired temperature profile may be a uniform temperature, for example, across the entire dryer housing, of, for example, 20°C to 200°C, or 100°C to 200°C, or 100°C to 150°C, or 120°C to 150°C. Due to convection or conduction heat loss, this may require uniform heating. The desired temperature profile may also be a non-constant temperature profile, for example, a time-dependent or moisture-dependent temperature profile.

[0089] One or more access heating subsystems may include one or more door heating elements integrated into the door of the dryer housing. Heating the door can contribute to controlling the temperature of the inner surface of the dryer housing and, in particular, can be used to create locally different zones in the door to prevent condensation.

[0090] One or more access heating subsystems may include one or more conveyor heating elements for heating an inlet conveyor for supplying herbal material into the internal space of the dryer receiving section or an outlet conveyor for removing herbal material from the internal space of the dryer receiving section. Heating the inlet conveyor or the outlet conveyor can prevent the formation of low-temperature points on each conveyor. Additionally, if the inlet conveyor is heated, the herbal material is preheated on the inlet conveyor before or during entry into the internal space of the dryer receiving section. The herbal material may also be preheated on the inlet conveyor before and during entry into the internal space of the dryer receiving section. Heating the inlet conveyor can prevent a decrease in temperature within the internal space of the dryer receiving section when new herbal material is introduced. If the outlet conveyor is heated, the herbal material may be finally heated on the outlet conveyor to remove residual moisture.

[0091] The heating subsystem may include a collector heating subsystem. The collector heating subsystem may include one or more collector heating elements for heating a collector provided within the internal space of the dryer receiving section to collect herbal material.

[0092] The dryer may further include a sensor that determines a temperature corresponding to each heating subsystem. According to one embodiment, one sensor determines a temperature corresponding to one heating subsystem, which may be a temperature in a temperature zone heated by the heating subsystem. Alternatively, the sensor may provide control feedback values ​​to more than one heating subsystem and determine a temperature corresponding to more than one heating subsystem, which may be a temperature in a temperature zone heated by the corresponding heating subsystem. The sensor may include one or more temperature sensors. The sensor may also include one or more steam sensors. In particular, one or more steam sensors may be used to determine a temperature within the dryer housing when heating with superheated steam.

[0093] The controller may be configured to control the heating subsystems based on the output from the sensors. In particular, the controller may be configured to control each heating subsystem or each group of heating subsystems based on the output from the corresponding temperature sensors.

[0094] The controller may be configured to control the heating subsystems based on different temperature target values ​​for different heating subsystems. This enables the establishment of different temperature zones with different temperatures to optimize the drying process. Preferably, the temperature target values ​​for the heating subsystems may be set or selected by the user.

[0095] Preferably, heating system information is routed wirelessly to the controller. Data from the heating subsystem can be transmitted wirelessly to the controller. In particular, measurement data from the sensor can be transmitted wirelessly to the controller. Additionally or alternatively, the controller may be configured to wirelessly transmit commands or data, or commands and data, to the heating subsystem.

[0096] According to one embodiment, the heating subsystem is arranged back and forth along a rotation axis. This allows, for example, different temperature zones or different temperature control zones to be established along the rotation axis.

[0097] The present invention further provides a method for drying herbal materials as described below. The features of the method may be combined with any one of the aforementioned dryer, method, or use. The method comprises the step of controlling a heating element for heating the herbal material in a dryer receiving portion. Different heating elements or groups of heating elements are controlled independently.

[0098] Preferably, different heating elements or groups of heating elements are controlled according to different temperature target values.

[0099] According to one embodiment, the temperature target value for the heating element provided on the side of the dryer receiving where the herbal material is supplied to the dryer receiving is higher than the temperature target value on the side of the dryer receiving where the herbal material is removed from the dryer receiving. Due to the higher temperature on the side where the herbal material enters the dryer receiving, the relatively wet herbal material entering the dryer receiving is treated at a relatively high temperature, and its moisture content is rapidly reduced. Since the herbal material is generally dried on the side of the dryer receiving, when the herbal material is removed from the dryer receiving, the risk of damaging or burning the herbal material due to high temperature is higher on that side of the dryer receiving. Due to the lower temperature target value on the side where the herbal material is removed from the dryer receiving, damage to the herbal material is prevented or the risk of damage to the herbal material is reduced.

[0100] Alternatively, the temperature target value for the heating element provided on the side of the dryer receiving where the herbal material is supplied to the dryer receiving is lower than the temperature target value on the side of the dryer receiving where the herbal material is removed from the dryer receiving. This allows the herbal material to be gently heated upon entering the dryer receiving to avoid damage or loss of flavor components, particularly volatile substances such as flavor components or oils. As the moisture of the herbal material decreases and the herbal material proceeds to the side of the dryer receiving, the herbal material is removed from the dryer receiving, and a higher temperature can remove residual moisture.

[0101] The present invention also provides the use of a heating element to create a temperature profile in the internal space of a dryer receiving portion that accommodates a herbal material to be dried. Preferably, the temperature profile extends along the rotational axis of the dryer receiving portion. The temperature profile may include a temperature gradient.

[0102] The present disclosure relates to a dryer for drying herbal materials, a method for drying herbal materials, and uses. Features, advantages, and descriptions presented in connection with any one of these aspects may also be applied to, combined with, and conveyed to any of the other aspects. Brief explanation of the drawing

[0103] In the following, the present invention is further described by explaining embodiments of the present invention with reference to the drawings. FIG. 1 shows a schematic perspective view of a dryer for drying a herbal substance according to one embodiment of the present invention; FIG. 2 shows a schematic cross-sectional view through a dryer according to an embodiment of the present invention, and the cross-section is parallel to the rotation axis of the dryer receiving portion; FIG. 3a is a schematic cross-sectional view showing the inner surface of the dryer receiving portion and a vane extending from the inner surface of the dryer receiving portion in a cross-section perpendicular to the rotational axis of the dryer receiving portion according to an embodiment of the present invention; FIG. 3b is a schematic cross-sectional view showing the inner surface of the dryer receiving portion and a vane extending from the inner surface of the dryer receiving portion in a cross-section perpendicular to the rotational axis of the dryer receiving portion according to an alternative embodiment of the present invention; FIG. 4 is a schematic perspective view of a channel shape collector and a part of a conveyor tube according to an embodiment of the present invention; FIG. 5 is a schematic diagram of the inner surface of the door of a dryer housing according to an embodiment of the present invention, as viewed from inside the dryer housing when the door is closed; and FIG. 6 is a block diagram schematically showing a control system of a dryer, particularly for a heating system of a dryer, according to an embodiment of the present invention. Specific details for implementing the invention

[0104] FIG. 1 shows a schematic partial view of a rotary dryer (1) for drying herbal materials, particularly tobacco materials. The rotary dryer (1) includes a dryer receiving section (3) having an internal space (5) for receiving herbal materials. The dryer receiving section (3) can be rotated about a rotation axis (10) of the dryer receiving section (3). The dryer receiving section (3) includes a main body (7) that extends along the rotation axis (10) from a first side (9) (inlet side according to the present embodiment) of the main body (7) to a second side (11) (outlet side according to the present embodiment) of the main body (7). In the illustrated embodiment, the main body (7) of the dryer receiving section (3) is substantially cylindrical in shape. However, other shapes of the main body (7), such as a prism shape, can be imagined, for example. The dryer receiving section (3) further includes a first door (13) provided on the first side (9) of the main body (7). Additionally, the dryer housing (3) includes a second door (15) provided on a second side (11) of the main body (7). The door (13, 15) can be opened to access the internal space (5) of the dryer housing (3) for maintenance or loading. When closed, the door (13, 15) provides a substantially hermetic seal together with the main body (7) of the dryer housing (3). The substantially hermetic seal enables control over the gas flowing in and out of the internal space (5) of the dryer housing (3). For example, the oxygen content within the internal space (5) of the dryer housing (3) can be controlled. According to one embodiment, overpressure is present in the internal space (5) of the dryer housing (3) to prevent ambient air from entering the internal space (5) of the dryer housing (3) in an uncontrolled manner. When the dryer housing (3) is rotated, the main body (7) and the door (13, 15) rotate together.

[0105] In some embodiments, the herbal material may be loaded into or removed from the dryer receiving section (3) through the opening door (13, 15) manually or automatically. However, in the illustrated embodiment, the herbal material is loaded into and removed from the internal space (5) of the dryer receiving section (3) when the door (13, 15) is closed. An inlet system (17) is provided at the first door (13) to supply the herbal material into the dryer receiving section (3). The inlet system (17) includes an inlet duct (19) extending through a central opening within the door (13). The inlet duct (19) is stationary and does not rotate with the dryer receiving section (3). The inlet duct (19) is connected to the first door (13) through a substantially hermetic rotation-blocking seal (21). Herbal material to be supplied to the internal space (5) of the dryer receiving section (3) is supplied to the inlet (23) of the inlet system (17). As illustrated in FIG. 2, an inlet conveyor (25) is provided inside the inlet duct (19). In the illustrated embodiment, the inlet conveyor (25) includes a conveyor screw that is rotated by a drive assembly (27) around a rotation axis that is parallel to and coaxial with the rotation axis (10) of the dryer receiving section (3). Alternatively, the inlet conveyor (25) may include a rotated spiral for supplying the herbal material into the internal space (5) of the dryer receiving section (3). As another alternative, the inlet conveyor (25) may include a scraper configured to move back and forth to supply the herbal material into the internal space (5) of the dryer receiving section (3). If the inlet conveyor (25) includes, for example, a conveyor screw, or a rotary spiral, or a scraper, the inlet conveyor (25) includes an active conveying system. However, the inlet conveyor (25) can alternatively be configured as a passive conveying system.In particular, the inlet conveyor (25) may include a chute for supplying herbal material into the internal space (5) of the dryer receiving section (3). The inlet conveyor (25) may be configured to supply herbal material into the internal space (5) of the dryer receiving section (3) without using any active driving components. The inlet conveyor (25) transports herbal material supplied to the inlet (23) of the inlet system (17) into the internal space (5) of the dryer receiving section (3).

[0106] Similarly, an outlet system (29) is provided at the second door (15) to draw out herbal material from the internal space (5) of the dryer receiving section (3). The outlet system (29) includes an outlet duct (31) extending through a central opening within the door (15). The outlet duct (31) is stationary and does not rotate with the dryer receiving section (3). The outlet duct (31) is connected to the second door (15) through a substantially hermetic rotation-blocking seal (33). As shown in FIG. 2, an outlet conveyor (37) is provided inside the outlet duct (31). The outlet conveyor (37) includes a conveyor screw that is rotated by a drive assembly (39) around a rotation axis that is parallel and coaxial with the rotation axis (10) of the dryer receiving section (3). Alternatively, the outlet conveyor (37) may include a rotary spiral for removing herbal material from the internal space (5) of the dryer receiving section (3). As another alternative, the outlet conveyor (37) may include a scraper configured to move back and forth to remove herbal material from the internal space (5) of the dryer receiving section (3). If the outlet conveyor (37) includes, for example, a conveyor screw, or a rotary spiral, or a scraper, the outlet conveyor (37) includes an active conveying system. However, the outlet conveyor (37) may also be configured as a passive conveying system. In particular, the outlet conveyor (37) may include a chute for removing herbal material from the internal space (5) of the dryer receiving section (3). The outlet conveyor (37) may be configured to remove herbal material from the internal space (5) of the dryer receiving section (3) without using any active driving components. The outlet conveyor (37) transports herbal material from the internal space (5) of the dryer receiving section to the outlet (35) of the outlet system (29).

[0107] As illustrated in FIG. 2, the dryer receiving portion (3) may be mounted on a tilting device (41) for adjusting the angle of inclination of the dryer receiving portion (3) with respect to a horizontal plane. In FIG. 2, the dryer receiving portion (3) is in a horizontal position, which means that the angle of inclination is 0. The tilting device (41) includes an arm (43) that carries the dryer receiving portion (3). The arm (43) can be tilted via a hinge (45) and a hydraulic cylinder (47), thereby lifting the inlet side (9) of the dryer receiving portion (3) with respect to the outlet side (11) to tilt the dryer receiving portion (3). The inclination device (41) may be configured to establish an inclination angle of, for example, 0 to 90 degrees, or 0 to 60 degrees, or 0 to 45 degrees, or 0 to 30 degrees, or 0 to 15 degrees, or 0 to 10 degrees.

[0108] The dryer (1) can be operated in two different operating modes. In batch mode, a load of herbal material is first loaded into the dryer receiving section (3), then dried within the dryer receiving section (3), and then removed from the dryer receiving section (3). During drying, the inlet conveyor (25) and the outlet conveyor (37) can be rotated to push the material back into the internal space (5) from the inlet and outlet sides (9, 11).

[0109] In detail, in batch mode, the herbal material to be dried can be introduced into the internal space (5) of the dryer receiving section (3) through the inlet system (17), while the inlet side (9) of the dryer receiving section (3) is raised relative to the outlet side (11). Preferably, the dryer receiving section (3) is rotated while the herbal material is introduced. Once all the material is loaded into the internal space (5) of the dryer receiving section (3), the tilting device (41) lowers the inlet side (9) of the dryer receiving section (3) until the dryer receiving section (3) is aligned horizontally. Then, the material is processed for a desired time while the dryer receiving section (3) is rotated. During this time, the inlet conveyor (25) and the outlet conveyor (37) can be rotated to push the material back into the internal space (5) from the inlet side (9) and the outlet side (11). After the desired time has expired, the inlet side (9) of the dryer receiving section (3) is raised again relative to the outlet side (11), and the rotation direction of the outlet conveyor (37) is reversed so that the outlet conveyor (37) transports the herbal material to the outlet (35). During this process, the dryer receiving section (3) can still rotate.

[0110] According to the continuous mode, the herbal material is introduced into the internal space (5) of the dryer receiving section (3) and continuously withdrawn from the internal space (5) of the dryer receiving section (3). The inlet conveyor (25) can rotate continuously to supply the herbal material from the inlet (23) to the internal space (5) of the dryer receiving section (3), while the outlet conveyor (37) rotates continuously to remove the herbal material from the internal space (5) of the dryer receiving section (3) to the outlet (35). The residence time of the herbal material within the internal space (5) of the dryer receiving section (3) can be controlled by appropriately setting the incline of the dryer receiving section (3) through the incline device (41). Additionally, or alternatively, the rotation speed of the dryer receiving section (3) can be controlled.

[0111] As described above, the dryer housing (3) is provided to be substantially airtight. Preferably, the drying of the herbal material within the dryer housing (3) is performed under specific atmospheric conditions. This enables better control over the process. Additionally, the yield of high-quality dried products can be improved by controlling the atmosphere within the dryer housing (3). The drying process can be performed under an inert gas atmosphere within the dryer housing (3). The inert gas within the internal space (5) of the dryer housing (3) can reduce the risk of fire. In particular, when processing tobacco material, it may be beneficial to perform the drying process under a nitrogen atmosphere. Nitrogen can function particularly as an inert gas. Additionally, other inert gases or mixtures of gases containing inert gases may be used. In particular, the atmosphere within the dryer housing (3) may contain noble gases. Nitrogen or other gases or mixtures of gases may be provided to the dryer housing (3), for example, through the gas inlet (62). In FIG. 2, a gas inlet (62) is illustrated as an example at the first door (13). Gas from the internal space (5) of the dryer receiving section (3) can be drawn out through the gas outlet (80). In FIG. 2, the gas outlet (80) is illustrated as an example at the outlet pipe (31) of the outlet system (29). The drying process can also be performed under vacuum.

[0112] Volatile substances evaporated in the dryer receiving portion (3) during the drying of the herbal material may be processed. These volatile substances may include, for example, flavor compounds evaporated during the drying of the herbal material, particularly during the drying of the tobacco material. The volatile substances may carry, for example, flavors extracted from the herbal material. The volatile substances may include, for example, aromatic substances or oils. The volatile substances may include, for example, alkaloids such as nicotine. The volatile substances may also include, for example, 2-methylpyrazine; 2,5-dimethylpyrazine; 2,6-dimethylpyrazine; 2-ethylpyrazine; 2,3-dimethylpyrazine; 2-ethyl-5-methylpyrazine; 2-ethyl-6-methylpyrazine; 2,3,5-trimethylpyrazine; tetramethylpyrazine; 2-ethyl-3,6-dimethylpyrazine; Or it may include pyrazines, such as 2-ethyl-3,5-dimethylpyrazine. Other examples of volatile substances include β-ionone; β-damashinone; or acetic acid.

[0113] To increase the drying efficiency and quality of the generated product, the herbal material inside the dryer receiving section (3) may be stirred during drying. This can be achieved by a vane (49) extending from the inner surface (51) of the dryer receiving section (3) into the inner space (5) of the dryer receiving section (3). Each vane (49) according to a first exemplary embodiment is illustrated in FIG. 3a, showing the inner surface (51) of the dryer receiving section (3) and the vane (49) in a cross-section having a cross-section perpendicular to the rotation axis (10) of the dryer receiving section (3). FIG. 3b shows a corresponding drawing according to a second exemplary embodiment. In the first embodiment illustrated in FIG. 3a, the vane (49) has a parallelepiped shape. The vane (49) according to the second embodiment illustrated in FIG. 3b has a curved shape.

[0114] According to both embodiments, the vane (49) is inclined radially in a cross section having a cross section perpendicular to the rotation axis (10) of the dryer housing (3), which is radially inclined with respect to the rotation axis (10). The angle of inclination of the vane (49) with respect to the radial direction is shown as an angle (20) in the drawing. To define the angle, the drawing shows a radius line (30) connecting the rotation axis (10) of the dryer housing (3) together with the center point of the base portion of the vane (49) in the cross-sectional view, the base portion is the part of the vane (49) where the vane (49) meets the inner surface (51) of the dryer housing (3). Additionally, the drawing shows an extension line (40) as a line connecting the center point of the base portion of the vane (49) to the center point of the far end portion of the vane (49), the far end portion of the vane is the part that reaches furthest into the inner space (5) of the dryer housing (3).

[0115] In the illustrated embodiment, the angle (20) between the vane (49) and the radial direction is the same for each vane (49). Preferably, the angle (20) is less than 30 degrees. In particular, the angle (20) may be 5 to 25 degrees, or more preferably 5 to 15 degrees.

[0116] The arrows in FIGS. 3a and 3b indicate the rotational direction of the dryer housing (3). As illustrated, the inclination of the vane (49) causes the angle between the vane (49) and the inner surface (51) of one of the dryer housings (3) to be greater when measured in the rotational direction of the dryer housing (3) than when measured in the rotational direction of the dryer housing (3). The angle is measured in both cases, starting from each vane (49) and ending at the inner surface (51) of the dryer housing (3). The larger angle measured in the rotational direction of the dryer housing (3) is indicated as angle (50) in the drawings, while the smaller angle measured in the rotational direction of the dryer housing (3) is indicated as 60. The angles (50 and 60) are redefined with reference to the extension line (40) of the vane (49). Generally, when the inner surface (51) of the dryer receiving portion (3) is a non-linear portion, the angles (50 and 60) can be measured by referring to the tangents to the inner surface (51) of the dryer receiving portion (3) at the center of the base portion of each vane (49).

[0117] As can be understood from FIGS. 3A and 3B, the engaging surface (53) of the vane (49) will engage with the herbal material contained in the dryer receiving portion (3) when the dryer receiving portion (3) is rotated around the rotation axis (10) in the rotational direction of the dryer receiving portion (3). The inclination of the vane (49) allows the vane (49) to engage better with the herbal material. Additionally, due to the inclination of the vane (49), a pocket (55) is formed between the vane (49) and the inner surface (51) of the dryer receiving portion (3). The pocket (55) can temporarily hold the herbal material while the dryer receiving portion (3) is rotating. Due to the inclination of the vane (49), the retention time of the herbal material within the pocket (55) is increased, thereby increasing the overall stirring in the dryer receiving portion (3). In addition, when the vane (49) is heated (see description below), the increased contact time between the inclined vane (49) and the herbal material increases the heating efficiency.

[0118] As the vane (49) shown in FIG. 3b is curved in the direction of the slope of the vane (49), a large amount of herbal material can be picked up by the vane (49). Since the herbal material can slide later than with a straight vane when the curved vane (49) rotates the dryer receiving portion (3), the curvature of the vane (49) can also increase the contact time between the vane (49) and the herbal material.

[0119] Preferably, the arch distance between two adjacent vanes (49) with respect to the rotation axis (10) is equal to or greater than the height dimension of the vane (49). This ensures that the adjacent vanes (49) do not too strongly interfere with the vane (49) picking up herbal material.

[0120] As illustrated in FIGS. 2 and 5, a collector (57) is provided in the internal space (5) of the dryer receiving section (3) at the outlet side (11). In the illustrated embodiment, the collector (57) is formed integrally with the outlet pipe (31) of the outlet system (29). However, the collector (57) and the outlet pipe (31) do not need to be formed integrally. For example, the collector (57) may be fixed to the outlet pipe (31) or another structure of the dryer (1). The collector (56) is stationary and does not rotate with the dryer receiving section (3). FIG. 4 shows a schematic perspective view of the collector (57) and the outlet duct (31). The collector (57) is channel-shaped and its upper portion is open. The collector (57) has at least two sections extending in different directions. The collector (57) may be, for example, essentially U-shaped, essentially V-shaped, or essentially U / V-shaped. In particular, the collector (57) may have a central section (59) forming the bottom of the collector (57) and two side sections (61) extending upward from opposite ends of the central section (59). The distance between the side sections (61) may increase in the direction away from the central section (59) (upward direction). When the dryer receiving portion (3) is rotated about its axis of rotation (10), the herbal material inside the dryer receiving portion (3) is agitated. While the dryer receiving portion (3) is rotating, the herbal material may enter the collector (57). In particular, the herbal material may be agitated and picked up by the vane (49) and fall into the collector (57) by gravity. The upward divergence of the side section (58) of the collector (57) leads to a funneling effect that funnels herbal material falling due to gravity toward the center section (59) of the collector (57).

[0121] The collector (57) constitutes a simple and effective method for collecting herbal material within the internal space (5) of the dryer receiving section. In particular, the collector (57) may be composed of or include a curved plate defining a central section (59) and a side section (58).

[0122] According to the illustrated embodiment, at least a portion of the upper rim of the collector (57) defining the upper opening of the collector (57) is slanted downward. In particular, the upper rim of the side section (58) of the collector (57) may be slanted downward. Herbal material falling from above onto the slanted rim may slide under the slanted rim instead of remaining on or sticking to the rim.

[0123] FIG. 5 shows a view of the inner surface of the second door (15) from inside the dryer receiving section (3). As illustrated, the rotation axis (10) of the dryer receiving section (3) extends within the collector (57). In particular, the collector (57) extends parallel to the rotation axis (10) of the dryer receiving section (3). An outlet conveyor (37) extends into the collector (57) through the outlet duct (31) and transports the herbal material collected within the collector (57) toward the outlet (35).

[0124] In the illustrated embodiment, the collector (57) is asymmetric with respect to the plane defined by the rotation axis (10) and the vertical direction. The asymmetric shape of the collector (57) can facilitate the collection of herbal material while the dryer receiving portion (3) rotates. In particular, one of the side sections (61) of the collector (57) may be longer than the other side section (58) of the collector (57). The shorter side section (58) can facilitate the entry of herbal material into the collector (57). The longer side section (58) can contribute to holding the herbal material within the collector (57). Preferably, the dryer receiving portion (3) is rotated such that the shorter side section (58) is downstream of the longer side section (58) with respect to the rotation direction of the dryer receiving portion (3).

[0125] The collector (57) may also be asymmetric with respect to the plane defined by the rotation axis (10) and the vertical direction in other ways. For example, the shape or dimensions of the side sections (58) of the collector (57) or the shape and dimensions may differ from each other. Additionally, the orientation of the side sections (58) of the collector (57) may differ from each other. Alternatively, the collector (57) may be symmetric with respect to the plane defined by the rotation axis (10) and the vertical direction.

[0126] As illustrated in FIG. 2, a liquid dispersion assembly having two nozzles (61) is provided. The nozzles (61) are provided at the ends of the conveyor screw of the inlet conveyor (25) and the conveyor screw of the outlet conveyor (37), respectively. Inside each conveyor screw, a channel (63) is provided to supply liquid to the nozzle (61). The nozzle (61) is configured to spray liquid into the internal space (5) of the dryer receiving section (3). During the drying of the herbal material, liquid for processing the herbal material can be sprayed through the nozzle (61). Additionally, when the dryer receiving section (3) is cleaned between uses, cleaning liquid can be sprayed by the nozzle (61). As the nozzle (61) rotates, the nozzle can reach even spots that are normally difficult to reach for cleaning. The nozzle (61) can be set to rotate together with each conveyor screw. Alternatively, the nozzle (61) can be blocked from the conveyor screw. For example, the nozzle (61) can be rotated by the liquid spray from the nozzle (61).

[0127] To facilitate the drying of herbal materials, the dryer (1) includes a heating system (65). The heating system (65) includes a plurality of heating elements, which may include a wall heating element (67), a vane heating element (69), a door heating element (71), a conveyor heating element (73), and one or more collector heating elements (74). The wall heating element (67) may be integrated into the circumferential wall of the main body (7) of the dryer housing (3). The vane heating element (69) may be integrated into a vane (49) that protrudes into the interior space (5) of the dryer housing (3). The door heating element (71) may be integrated into the first and second doors (13, 15) of the dryer housing (3). The conveyor heating element (73) may be integrated into the inlet conveyor (25) and the outlet conveyor (37). The collector heating element (74) can be integrated into the collector (57). The wall heating element (67), vane heating element (69), and door heating element (71) are illustrated in FIG. 2. The conveyor heating element (73) and the collector heating element (74) are not illustrated in FIG. 2 for clarity. The conveyor heating element (73) can be integrated, for example, into the conveyor screw of the inlet conveyor (25). Alternatively or additionally, the conveyor heating element (73) can be integrated, for example, into the outlet conveyor (37). The conveyor heating element (73) can also be integrated into the inlet pipe (19). Alternatively or additionally, the conveyor heating element (73) can also be integrated into the outlet pipe (31).

[0128] The first and second doors (13, 15) and the inlet and outlet conveyors (25, 37) are part of an access assembly that provides access to the internal space (5) of the dryer receiving section (3). Heating this access assembly by the door heating element (71) and the conveyor heating element (73) facilitates maintaining a specific temperature level within the dryer receiving section (3). If only the wall heating element (67) and the vane heating element (69) are present, parts of the access assembly such as the doors (13, 15) or the conveyors (25, 37) may provide space for the formation of a low-temperature point. At the low-temperature point, gaseous substances generated while the herbal material within the dryer receiving section (3) is being dried may condense, which may have a negative effect on the drying efficiency and quality of the dried material.

[0129] Heating the vane (49) with a vane heating element (69) integrated into the vane (49) is very effective because the vane (49) comes into direct contact with a large amount of herbal material when stirring the herbal material. Additionally, as the vane (49) is inclined, the duration of contact between the herbal material and the vane (49) increases. This can increase heating efficiency.

[0130] Heating the collector (57) with the collector heating element (74) can help remove residual moisture before the herbal material leaves the internal space (5) of the dryer receiving section (3).

[0131] The block diagram illustrated in FIG. 6 shows the control scheme of the heating system (65). Heating elements (67, 69, 71, 73, 74) are grouped into heating subsystems (75), and these heating subsystems are controlled independently of each other by a controller (78).

[0132] According to the illustrated embodiment, five distinct body heating subsystems (75a) are provided. Each body heating subsystem (75a) includes a plurality of wall heating elements (67) and a plurality of vane heating elements (69). Alternatively, instead of providing a body heating subassembly (75a) that includes both wall heating elements (67) and vane heating elements (69), a wall heating subassembly and a vane heating subassembly that are controlled separately are provided. As illustrated in FIG. 2, there are five columns of wall heating elements (67) and five columns of vane heating elements (69) along the extension direction of the rotation axis (10) of the dryer housing (3). These correspond to the five body heating subsystems (75a). This means that, according to the illustrated embodiment, the wall heating element (67) and the vane heating element (69) are grouped into a body heating subassembly (75a) by defining a group of heating elements (67, 69) that are positioned back and forth along a direction parallel to the rotational direction A of the dryer housing (3). Independent control of the body heating subassembly (75a) by the controller (78) enables the establishment of independently controlled heating zones along the extensional direction of the rotational axis (10) of the dryer housing (3).

[0133] According to the illustrated embodiment, the heating system (65) further comprises two door heating subassemblies (75b). Each door heating subassembly (75b) comprises a door heating element (71) integrated into a corresponding one of the first and second doors (13, 15). Independent control of the two door heating subassemblies (75b) by the controller (78) enables, for example, the first and second doors (13, 15) to be heated to different temperatures. Additionally, the first and second doors (13, 15) may be heated to the same target temperature but with different feedback control parameters.

[0134] Additionally, according to the illustrated embodiment, the heating system (65) includes two conveyor heating subsystems (75c). The conveyor heating subsystem (75c) may include one conveyor heating element (73) corresponding to the inlet conveyor (25) and the outlet conveyor (37).

[0135] Additionally, according to the illustrated embodiment, the heating system (65) includes a collector heating subsystem (75d). The collector heating subsystem (75d) may include one or more collector heating elements (74).

[0136] FIG. 6 schematically shows temperature sensors (77) distributed at appropriate locations in the dryer (1) to measure the temperature corresponding to each heating subsystem (75). FIG. 6 shows 10 temperature sensors (77), one for each heating subsystem (75). Each temperature sensor (77) is equipped with a wireless transmitter (79) that wirelessly transmits each temperature sensor value to a controller (78). Alternatively, there may be a wired connection between the temperature sensors (77) and the controller (78). The controller (78) controls each heating subsystem (75) based on the output of the corresponding temperature sensor (77). In the illustrated embodiment, the heating subsystems (75) are all controlled independently of each other based on the detected values ​​from each temperature sensor (77). However, it may also be possible to group some or all of the heating subsystems (75) to be controlled together, or at least control them based on the output of the same temperature sensor (77).

[0137] By having independently controlled heating subassemblies (75), a high level of control over the temperature distribution within the dryer receiving section (3) is provided during the drying of the herbal material. Thus, the drying process can be precisely controlled and adjusted to obtain a high-quality product. Depending on the herbal material to be processed and the desired characteristics of the product to be obtained, different principles for operating the heating subsystem (75) may be devised. For example, the main body heating subassembly (75a) may be controlled to provide a temperature gradient in the internal space (5) of the dryer receiving section (3) along the extension direction of the rotation axis (10) of the dryer receiving section (3). This can be achieved, for example, by using different temperature target values ​​for controlling different main body heating subassemblies (75a). For example, the temperature gradient may be such that the temperature is higher on the inlet side (9) of the dryer receiving section (3) and lower on the outlet side (11) of the dryer receiving section (3). Alternatively, the temperature gradient may be established such that the temperature is lower at the inlet side (9) of the dryer receiving section (3) and higher at the outlet side (11) of the dryer receiving section (3). The temperature difference between each of the inlet and outlet sides (9) may be, for example, at least 10°C, at least 20°C, at least 30°C, at least 50°C, at least 100°C, or more than 100°C.

[0138] Additionally, while it would be possible to use the same temperature target value for all body heating subassemblies (75a), it would be possible to achieve a highly uniform temperature throughout the entire length of the dryer housing (3) by using the detection values ​​from different temperature sensors (77) for each body heating subassembly (75a) for independent control suitable for the characteristics of the body heating subassembly (75a), such as heat capacity.

[0139] The door heating subassembly (75b) and the conveyor heating subassembly (75c) are preferably controlled to maintain at least a predetermined minimum temperature, i.e., the minimum access assembly temperature, at each of the door (13, 15) or the inlet and outlet conveyors (25, 37). The minimum access assembly temperature may be selected so as to prevent the formation of a cold spot in the access assembly, particularly at the door (13, 15) or the conveyor (25, 37). Preventing a cold spot can prevent the condensation of gaseous material generated during drying of the herbal material at these spots.

[0140] The door heating subassembly (75b) is preferably controlled based on different temperature target values ​​for the first door (13) and the second door (15). This can be done in combination with a temperature gradient established by appropriately controlling the body heating subassembly (75a), in particular.

[0141] The temperature target value for each heating subsystem (75) can be entered by the user through the input device (81). Alternatively or additionally, the temperature target value for each heating subsystem (75) can be stored in the memory device (83).

[0142] FIG. 6 also shows an optional pressure sensor (82). The pressure sensor (82) may be configured to determine the pressure within the internal space (5) of the dryer housing (3). When superheated steam is used to heat the internal space (5) of the dryer housing (3), the temperature within the internal space (5) of the dryer housing can be inferred from the determined pressure. The pressure determined by the pressure sensor (82) may be transmitted wirelessly to a controller (78) and may be used to control one or more of the heating subassemblies (75).

[0143] In FIG. 6, each heating subsystem (75) includes an actuator (85) controlled by a controller (78) to properly operate each heating element (67, 69, 71, 73, 74). The actuator may include an electrical circuit for supplying a resistance heating element to power, a pump, or a valve to provide a heating element configured as a heating fluid line having a properly heated fluid, for example.

[0144] Additionally, the controller (78) may be configured to control a drive device (90) for rotating the dryer receiving section (3) around the rotation axis (10). Preferably, the controller (78) is configured to control the drive device (90) to rotate the dryer receiving section (3) in only one rotational direction. However, the controller (78) may also be configured to control the drive device (90) to change the rotational direction of the dryer receiving section (3). In particular, the rotational direction of the dryer receiving section (3) may be changed at intervals to improve the distribution of herbal material within the dryer receiving section (3). The controller (78) may also control the hydraulic cylinder (47) of the inclination device (41).

Claims

Claim 1 A rotary dryer for drying herbal materials, comprising: a dryer receiving portion having an internal space for receiving herbal materials; a driving device for rotating the dryer receiving portion around a rotation axis of the dryer receiving portion; and a channel-shaped collector provided in the internal space of the dryer receiving portion, the upper portion of which is at least partially open to collect the dried herbal materials, wherein the channel-shaped collector is stationary while the dryer receiving portion rotates, and the channel-shaped collector is asymmetric with respect to a plane defined by the rotation axis and vertical direction of the dryer receiving portion. Claim 2 A rotary dryer according to claim 1, wherein the channel shape collector extends at least substantially parallel to the rotation axis. Claim 3 A rotary dryer according to claim 1 or 2, wherein the rotation axis of the dryer receiving portion extends within the channel shape collector. Claim 4 A rotary dryer according to claim 1 or 2, wherein the channel shape collector is located at the end of the dryer receiving portion with respect to the extension direction of the rotation axis. Claim 5 A rotary dryer according to claim 1 or 2, wherein the channel shape collector is provided at the door of the dryer receiving portion. Claim 6 A rotary dryer according to claim 1 or 2, wherein the cross-section of the channel shape collector has two sections extending in different directions, and the distance between the two sections increases in the upward direction. Claim 7 A rotary dryer according to paragraph 6, wherein one of the above sections is shorter than the other. Claim 8 A rotary dryer according to claim 7, wherein the length of the shorter section is at least 60% of the length of the longer section, or at least 70% of the length of the longer section. Claim 9 A rotary dryer according to claim 1 or 2, further comprising an outlet conveyor configured to remove dried herbal material collected in the channel-shaped collector from the internal space of the dryer receiving portion. Claim 10 A rotary dryer according to claim 9, wherein the outlet conveyor includes a conveyor extending within the channel-shaped collector and outside the dryer receiving portion. Claim 11 In claim 10, a rotary dryer provided on the conveyor through which a nozzle for spraying fluid reaches into the internal space of the dryer receiving portion. Claim 12 A rotary dryer according to claim 1 or 2, wherein the dimension of the channel shape collector in a direction perpendicular to the rotation axis is smaller than half the dimension of the internal space of the dryer receiving portion in a direction perpendicular to the rotation axis. Claim 13 A rotary dryer according to claim 1 or 2, further comprising a collector heating element configured to heat the channel-shaped collector. Claim 14 A rotary dryer according to claim 1 or 2, wherein the dryer receiving portion is configured to rotate around the channel-shaped collector. Claim 15 A method for drying a herbal substance, comprising: a step of rotating a dryer receiving portion that receives the herbal substance around a rotation axis of the dryer receiving portion; and a step of collecting the herbal substance dried in the dryer receiving portion into a collector comprising a plate that partially surrounds the rotation axis, wherein the collector is decoupled from the rotation of the dryer receiving portion and the collector is asymmetric with respect to a plane defined by the rotation axis and a vertical direction of the dryer receiving portion. Claim 16 A method for drying herbal material according to claim 15, wherein the dryer receiving portion rotates around the collector. Claim 17 A curved plate used to collect herbal material during a drying process of herbal material in a dryer receiving portion that rotates about the rotation axis of the dryer receiving portion, wherein the curved plate is stationary while the dryer receiving portion rotates, and the curved plate is asymmetric with respect to a plane defined by the rotation axis and vertical direction of the dryer receiving portion. Claim 18 In paragraph 17, the above-mentioned dryer receiving portion is a curved plate used to collect herbal material, which rotates around the curved plate.

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