Drying and storage unit for organic material, and operating method

Abstract

The present invention relates to a drying unit for use in a drying container for gently drying organic material, in particular plant material, which drying unit is designed to dehumidify ambient air on the basis of chemical dehumidification by means of a chemical dehumidifier, with the intensity of the chemical dehumidification being controllable.

Description

[0001] Drying and storage unit for organic material and operating procedures

[0002] Field of the invention

[0003] The present invention relates to the field of drying and gentle, quality-preserving storage of organic material, in particular plant material.

[0004] Technical background

[0005] For numerous technical applications, it is necessary to dry organic material. The dried material must then be stored until use or further processing.

[0006] Often, the desired degree of drying or the type of drying is not achieved, or it cannot be maintained during further storage of the material. Further negative impacts on the material or its quality regularly occur. Some of these negative impacts are outlined below as examples.

[0007] Drying organic, moist material always carries a high risk of mold and / or rot. This is particularly the case with inadequate and / or slow drying processes, but can also occur under other conditions.

[0008] The material is frequently exposed to the surrounding air, from which it can absorb pathogens. This factor also contributes to a high risk of mold and / or rot.

[0009] The actual environmental conditions during air drying are often uneven and difficult to control. This leads to uneven drying processes. Drying processes that are too fast are also common. For example, only the outer layers of the material are dried, but the inner core exhibits undesirable and / or uncontrolled properties with regard to the drying process. This is particularly common with "heat drying."

[0010] In these scenarios, the final product is often also altered (e.g., temperature-sensitive ingredients, flavors, and / or potentially active ingredients (e.g., medicinal and / or therapeutic)). This is also frequently observed with simple air drying.

[0011] The results are often suboptimal. Furthermore, the results are difficult to reproduce. The result is many unusable batches, followed by a few batches of highly variable quality.

[0012] Chemical dehumidifiers are also generally known. A hygroscopic desiccant can be installed, for example. For example, calcium chloride crystals (CaCl2) are used to dehumidify excessively damp basements to reduce moisture damage and the risk of mold. These crystals remove humidity from the surrounding air, thereby drying the basement. However, this type of drying process is far too aggressive for drying plant material, which requires careful drying, as recognized by the relevant experts. Due to this high level of aggression, drying with a chemical dehumidifier occurs too quickly and unevenly. The humidity drops too quickly, which is why chemical dehumidifiers are systematically avoided in these applications.

[0013] Dehumidifiers for plant material based on heat pumps and / or Peltier elements have been proposed. These devices are often also referred to as compression dehumidifiers. In this case, a drop below a dew point is used to condense existing humidity. A disadvantage of this process is the very high demand for electrical energy, which must be continuously supplied. Further disadvantages are briefly outlined below.

[0014] In an exemplary design of a compression dehumidifier, both a warm and a cold side are located in a room containing the plants. The temperature in the room continuously increases. The result is rapid, irregular, and uncontrolled drying.

[0015] In another example of a compression dehumidifier, only the cold side is in the room. As the temperature drops, the dehumidifier's performance also decreases. The dew point is low. The result is weaker, yet still inconsistent, dehumidification.

[0016] Often, an exchange with ambient air is necessary (e.g., well-known solutions from Autocure). In addition to the disadvantages already mentioned, this often involves additional effort and energy consumption.

[0017] JP 2002 106889 A discloses a device for the physical dehumidification of air within a closed volume to achieve low air humidity for object storage. This allows moisture damage to be avoided in laboratories during storage of, for example, expensive electronic devices. However, the method is not suitable for a drying process (material drying), especially not for organic material. A particular disadvantage is that special cycles (regeneration cycles) are necessary for the regeneration of desiccants. This is resource-intensive and time-consuming. Alternatively, at least two units must be operated to stagger the required regeneration cycles. A further disadvantage is that the effect of the desiccant cannot be prevented when needed, since contact with the air always exists.The desiccant cannot be completely sealed off from the main chamber. This also has the disadvantage that certain precise measurements (e.g., VPD) are not possible, as these measurements depend on sealing. Another disadvantage is that the drying process is based solely on measuring the humidity prevailing in the drying chamber, without any parametric reference to the stored (or organic, to-be-dried) material (e.g., VPD). Another disadvantage is the existence of a connection to the outside.

[0018] The rotary dehumidifier essentially consists of a honeycomb structure coated with a dehumidifying agent (e.g., silica gel). The necessary regeneration occurs continuously during operation in sections of the dehumidifier. Slow rotation continuously transports water-laden sections from the drying section to the regeneration section. There, as is usual during regeneration, the water is expelled with heated air. The warm, humid air must be removed from the drying container, usually through exhaust vents. The dehumidification and regeneration airflow sections of the rotary dehumidifier are structurally separated, e.g., by metal sheets. These separate the drying and regeneration airflows. Two airflows are required. Structural complexity: very high (controlled rotation speed, structural separation of the airflows, air heating, continuous supply and removal of regeneration air).Furthermore, the rotary dehumidifier must practically run through a cooling phase after regeneration to prevent the temperature in the drying room from increasing due to the stored heat. Rapid adjustment of the dehumidification performance is not possible with a rotary dehumidifier.

[0019] As a result, the possibilities for qualitative drying of organic material in the prior art are disadvantageous and unsatisfactory. The present invention aims to remedy this situation.

[0020] The present invention is therefore based on the technical problem of providing a drying unit and a relevant drying method that overcome the disadvantages of the prior art. In addition to drying in the narrower sense, proper curing with high-quality results should also be ensured. The solution should also be environmentally friendly, enable a high degree of recyclability, and, in particular, keep running costs low. A "smart" solution is sought that is suitable for meeting the high demands of modern consumers and users. The disadvantages of the prior art are overcome by the drying unit according to claim 1 and the method according to claim 27.

[0021] Description of the invention

[0022] The present invention provides a device with the features of claim 1. Further advantageous embodiments are specified in the subclaims. A drying unit for gently drying organic, in particular plant, material can be provided. The drying unit can, for example, dry but also store (cure) the material under suitable conditions. The drying unit can be designed for use in a drying container, for example, a food barrel. The material to be dried can, for example, be placed in the drying container, for example, in air-permeable bags that are suspended or the like.

[0023] The drying unit can be configured to remove moisture from the circulating air based on chemical dehumidification using a chemical dehumidifier. The intensity of the chemical dehumidification can be designed to be controllable. The chemical dehumidifier can be a granulate. For example, the chemical dehumidifier can be arranged in a granulate tray. Variable openings (inlet openings, outlet openings) to the granulate tray can be provided. For example, fans, ventilators, or other means of air circulation are used. Their effectiveness or speed can also be controlled. This allows for precise control. For example, this is done using a control program, for drying or curing, for example. The term "drying unit" (or drying and storage unit) is not limiting in this regard. The term refers to the mode of action (it can make air drier, i.e.reduce the humidity (especially absolute, but also relative). However, in one embodiment, a drying unit may also include means for increasing, maintaining, and / or stabilizing humidity.

[0024] An example of a chemical dehumidifier is CaCl2. A chemical dehumidifier can be hygroscopic or comprise a hygroscopic material. The granulate tray can be designed with drainage openings. This allows an aqueous solution of dissolved drying agent to flow away, for example into a collecting container provided for this purpose. The drying unit can in particular be housed in or inserted into a hermetically sealable and / or sealed vessel. For example, this could be a food barrel. A further recirculation unit can be provided to ensure circulation. The recirculation unit can comprise one or more fans. Here, too, the speeds of the fans / ventilators and the effectiveness of the air circulation to be stimulated are adjustable and can be specified as part of a complex overall system control. In particular, for particularly thorough ventilation orFurther measures may be provided to ensure this. For example, the intensity of air circulation is periodically increased continuously (or in discrete steps) and then decreased again. The drying unit and / or the chemical dehumidifier (and related methods) may, in particular, be based on dehumidification by absorption. This may, in particular, be in contrast to adsorption-based techniques. The latter are therefore not to be considered chemical dehumidifiers within the meaning of the present invention.

[0025] Chemical dehumidification can be performed continuously, especially in the presence of the desiccant described above. Regeneration is not necessary or possible. However, regeneration is required for adsorption-based processes (see below).

[0026] Adsorption is generally a process in which water molecules bind to the surface of a material (adsorbent) without penetrating or changing the structure of the material. It is usually a surface phenomenon in which the water molecules adhere unevenly to the surface of the adsorbent.

[0027] Adsorption-based processes require regeneration. Typically, several regeneration cycles are required before the desired drying level can be achieved. Typically, a drying process must be interrupted for such a regeneration cycle. This costs time and resources and causes adverse discontinuities.

[0028] Dehumidification by adsorption occurs more slowly than by absorption. The surface area becomes clogged during the drying process, and the adsorption capacity and thus the dehumidification performance steadily decrease. At some point, the material is so loaded that hardly any more adsorption can take place; it is in a state of equilibrium. Then the adsorbent must be regenerated. This is usually done by heating; during this time, no dehumidification can take place. Furthermore, the moisture escaping during regeneration must be removed, usually through an opening in the drying room. Regeneration therefore entails increased structural complexity. Dehumidification cannot occur continuously, or multiple drying units must be used, which alternately dehumidify and regenerate, which further increases the structural complexity.The adsorption capacity, i.e., the amount of water that can be bound, is significantly lower than with absorption, since only the surface is active. For silica gel, one can assume approximately 20 percent by weight; 1 kg of silica gel can bind approximately 200 grams of water.

[0029] Absorption, on the other hand, is generally a process in which water molecules penetrate into the interior of a material (absorbent). It is a volumetric phenomenon in which mass transport with uniform distribution occurs within the absorbent. This can change the structure of the absorbent.

[0030] Dehumidification by absorption can occur continuously if a desiccant is present. A regeneration phase, during which drying cannot be carried out with a drying unit, is unnecessary. The dehumidification performance is consistently high. The absorption capacity, i.e., the amount of water that can be absorbed, is significantly higher than with adsorption-based desiccants. For example, 1 kg of calcium chloride can bind approximately 970 grams of water.

[0031] The invention may comprise and / or be based on means for controlling, regulating, and / or monitoring the effectiveness of a chemical dehumidifier. In particular, the invention may comprise means for controlling, regulating, and / or monitoring the effective effectiveness of a chemical dehumidifier by controlling, regulating, and / or monitoring an air flow, velocity, and / or circulation. For example, one or more air access openings can be adjusted in size and / or quality, and / or an air flow excitation can be adjusted, in particular modulated over time.

[0032] Control using "smooth" transitions in relation to the ambient parameters is particularly suitable. The temporal modulation can therefore be deliberately accelerated, but also delayed, to ensure effective drying while simultaneously ensuring gentle drying. For example, deliberate control using temporal transitions / intensity profiles dl / dt is particularly suitable. The temporal profile can, of course, be subject to feedback from measured variables, particularly temperature and (especially relative) humidity (RH).

[0033] A recirculation unit may be provided. For example, this could be a fan. As already mentioned above, it can be advantageous to modulate the intensity of the recirculation unit (e.g., fan speed), even with constant environmental factors, for example, by slowly increasing it to a maximum speed and then reducing it again. As shown, this improves overall ventilation because poorly ventilated areas are avoided by this technique. Background: the container is not empty during normal operation; during each drying process, the bags hang in the drum (in different positions). The recirculation and drying units represent additional obstacles to the airflow. Preferred airflows emerge. This creates areas with stronger and weaker air movement. Varying the fan speed causes changing airflows (especially airflow topologies) and reduces these areas on average.The increase and decrease of the speed occurs, for example, step by step (numerically discrete), for example once per minute (once per cycle time, e.g. cycle time of a drying program / main program).

[0034] Furthermore, a measurement method for aw values ​​is also being developed. The aw measurement method can be used seamlessly or on-the-fly within a drying process. The actual drying process can, for example, be interrupted or temporarily suspended for this purpose. The method can also make adjustments to drying process parameters – particularly with regard to the degree of dryness already achieved, the drying gradient of the material being dried, etc. – within the framework of recurring aw measurement cycles.

[0035] Furthermore, VPD drying can be provided optionally. This type of drying is particularly gentle for many materials. For a better and more detailed, albeit exemplary, understanding of the embodiments, reference is made to the figures and the associated figure descriptions.

[0036] All features disclosed in connection with corresponding methods can be used in connection with the devices, and vice versa.

[0037] Although some aspects have been described in the context of a device, it is clear that these aspects also represent a description of the corresponding method, with a block or device corresponding to a method step or a function of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block, element, or property of a corresponding device.

[0038] Embodiments of the invention may be implemented in a computer system. The computer system may be a local computing device (e.g., personal computer, laptop, tablet computer, or mobile phone) having one or more processors and one or more memory devices, or may be a distributed computing system (e.g., a cloud computing system having one or more processors or one or more memory devices distributed at different locations, for example, at a local client and / or one or more remote server farms and / or data centers). The computer system may comprise any circuitry or combination of circuits. In one embodiment, the computer system may comprise one or more processors, which may be of any type.As used herein, processor may mean any type of computing circuit, such as, but not limited to, a microprocessor, a microcontroller, a complex instruction set microprocessor (CISC), a reduced instruction set microprocessor (RISC), a very long instruction word (VLIW) microprocessor, a graphics processor, a digital signal processor (DSP), a multi-core processor, a field-programmable gate array (FPGA), or any other type of processor or processing circuit. Other types of circuitry that may be included in the computer system may be a purpose-built circuit, an application-specific integrated circuit (ASIC), or the like, such as one or more circuits (e.g., a communications circuit) for use with wireless devices such asMobile phones, tablet computers, laptop computers, two-way radios, and similar electronic systems. The computer system may include one or more storage devices, which may include one or more storage elements suitable for the particular application, such as main memory in the form of random access memory (RAM), one or more hard disks, and / or one or more drives handling removable media such as CDs, flash memory cards, DVDs, and the like. The computer system may also include a display device, one or more speakers, and a keyboard and / or controller, which may include a mouse, trackball, touchscreen, voice recognition device, or any other device that allows a system user to input information to and receive information from the computer system.

[0039] Some or all of the method steps may be performed by (or using) a hardware device, such as a processor, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the key method steps may be performed by such a device.

[0040] Depending on specific implementation requirements, embodiments of the invention may be implemented in hardware or software. The implementation may be performed using a non-volatile storage medium, such as a digital storage medium, such as a floppy disk, DVD, Blu-ray, CD, ROM, PROM and EPROM, EEPROM, or FLASH memory, on which electronically readable control signals are stored that interact (or can interact) with a programmable computer system to perform the respective method. Therefore, the digital storage medium may be computer-readable.

[0041] Some embodiments according to the invention comprise a data carrier with electronically readable control signals that can interact with a programmable computer system so that one of the methods described herein is carried out.

[0042] In general, embodiments of the present invention can be implemented as a computer program product with program code, wherein the program code is effective for executing one of the methods when the computer program product is running on a computer. The program code can, for example, be stored on a machine-readable medium.

[0043] Further embodiments include the computer program for carrying out one of the methods described herein, which is stored on a machine-readable carrier.

[0044] In other words, one embodiment of the present invention is therefore a computer program having a program code for carrying out one of the methods described herein when the computer program runs on a computer.

[0045] A further embodiment of the present invention is therefore a storage medium (or a data carrier or a computer-readable medium) comprising a computer program stored thereon for performing one of the methods described herein when executed by a processor. The data carrier, the digital storage medium, or the recorded medium is typically tangible and / or non-seamless. A further embodiment of the present invention is an apparatus as described herein, comprising a processor and the storage medium.

[0046] A further embodiment of the invention is therefore a data stream or signal sequence representing the computer program for carrying out one of the methods described herein. The data stream or signal sequence can, for example, be configured to be transmitted via a data communication connection, for example, via the Internet.

[0047] A further embodiment comprises a processing means, for example a computer or a programmable logic device, configured or adapted to carry out any of the methods described herein.

[0048] A further embodiment comprises a computer on which the computer program for carrying out one of the methods described herein is installed.

[0049] A further embodiment according to the invention comprises a device or system configured to transmit (e.g., electronically or optically) a computer program for performing one of the methods described herein to a recipient. The recipient may, for example, be a computer, a mobile device, a storage device, or the like. The device or system may, for example, comprise a file server for transmitting the computer program to the recipient.

[0050] In some embodiments, a programmable logic device (e.g., a field-programmable gate array, FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field-programmable gate array may cooperate with a microprocessor to perform any of the methods described herein. In general, the methods are preferably performed by any hardware device.

[0051] Description of the drawings

[0052] The present invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawings.

[0053] In all figures, identical or functionally identical elements and devices have been provided with the same reference numerals, unless otherwise stated.

[0054] Figure 1 shows a hermetically sealable drying container 300 (here, a food drum 300) into which a drying unit 100 is inserted according to one embodiment. A removable ultrasonic humidifier 101 may be provided. A recirculation unit 200 is provided and, in this embodiment, is arranged directly beneath the lid of the food drum. As shown in Figure 2, the recirculation unit 200 may comprise a fan 203. Bags 302 containing dry goods may be arranged on suspensions 301. The drum lid 210 may have a (hermetically sealed, see later discussion) opening for the purpose of power supply and, if necessary, for the wired transmission of electrical signals. A clamping ring 303 can securely and tightly fasten the lid 210 to the container 300. The recirculation unit 200 is shown enlarged in Figure 3.Shown here are both the part 201 located outside the drum 300 during intended use, and the internal part (the actual recirculation unit 200). The counterpart / holder 201 with thread and seal can be screwed to the fan mount / holder 202 of the recirculation unit using the thread (shown screwed here, but without the vessel wall with the opening). The holder 202 holds the fan 203. The recirculation unit 200 can be connected to the drying unit 100 via a cable 205. The holder 204 carries part of the control electronics, and in particular also a humidity and temperature sensor 206. By recording the measured variables in this area, the measured values ​​are particularly representative (for the ambient parameters of the material being dried) and stable (especially with regard to changing air flow velocities and air flow topologies – more on this in the context of a discussion of the operating procedures).Figure 5 also shows, in addition to the screw connection 207, an attachable and removable external unit 208 (by plugging in). Two exemplary embodiments are presented in the figures: one variant for a power supply only (the system is controlled, for example, via wireless technology such as Bluetooth or Wi-Fi), and another alternative variant with a display and control buttons (e.g., a directional pad). Individual features of the variants can also be combined. The exemplary variants mentioned are shown in Figures 6 and 7.

[0055] The screw connection is shown in more detail in Figure 8. The external unit-side counterpart 201 has an external thread, while the internal fan holder 202 has a matching internal thread. Silicone flat gaskets 212a, b ensure hermetic sealing, together with the circuit board 214 (featuring electrical connectors on both sides) glued and / or encapsulated into the external screw connection.

[0056] Figure 9 shows an exploded view of a drying unit 100. The drying unit 100 has a tray 106 for the desiccant granules (the chemical dehumidifier), as well as a collecting tray 108 underneath for liquid. The tray 106 has corresponding, liquid-permeable drainage openings in the bottom. A cover plate 105 rests on the granule tray 106, which simultaneously serves as a support for mechanical components (see the following discussion). The cover plate 105 has recesses 121. These can be designed, in particular, as inlet openings for air or for use as outlet openings. Effective air supply and removal can be regulated by means of the rotatable slides 104a, 104b and the recesses 120, 122 provided therein. This depends on the position of the slides (and thus the overlap of the openings in the slides with corresponding openings 121 in the cover plate).A stepper motor 103 can adjust or adjust the slides. (Other motors, for generating linear and / or rotary motion, are also conceivable as drive means.) Finally, the adjustment of the slides can be performed rotaryly, for example, as shown here, which has further advantages. In the example shown, the stepper motor 103 adjusts the air outlet slide 104b, while the slide 104a for the air inlet is moved via two connectors 102a, 102b. The connectors can move in opposite directions, made possible by the rotary slides. This design is particularly stable and compact. The air inlet is supplied with incoming air via a fan 110 (alternatively, an air outlet can also be operated with a fan arranged in intake mode). In the example shown, the air inlet slide 104a has four openings, while the air outlet slide 104b only two.The slider with two openings creates space for additional elements (light barriers, etc., see discussion later). The slider with four openings utilizes the full potential of the fan. Therefore, regardless of the air inlet and outlet or the air flow direction, it is advisable to arrange a slider that encompasses as much of a circle as possible on one side with the fan, and to use the smaller slider on the opposite side in order to be able to use the space for additional devices if necessary. For example, a retro-reflective light barrier 112 can be provided. This can be directed towards a guided rod with a gray scale 113. The rod with a gray scale indicates, for example, the fill level of the granulate remaining in the tray 106 and can thus be optically evaluated via the retro-reflective light barrier 112. A fill level sensor 107 can be provided for the collecting tray to prevent the tray from overflowing and enable timely emptying.

[0057] Figure 10 shows a drying unit 100 with an ultrasonic humidifier 101 mounted thereon (see Figure 23). As shown in Figure 13, this can discharge atomized water through an opening 186, which can increase and, in particular, maintain a stable humidity.

[0058] Figure 15 shows a top view of a drying unit 100 (without cover and fan). The circuit board 114 (PCB 114) can accommodate the reflex light barrier 112 and / or the forked light barrier 116 and process their signals. Using the forked light barrier 116, the reference position (zero position) of the sliders 104a,b can be precisely determined.

[0059] Figure 16 shows a side view of a drying unit 100. The covers 130, 131 have corresponding inlet and outlet openings 130b, 131b. These can be arranged laterally, as shown: This protects, for example, against falling drying material, other particles, and the like. A light-tight cover 115 protects the reflex light barrier 112 from external influences such as ambient light, thereby ensuring reliable operation. A Wi-Fi and Bluetooth-enabled microcontroller 137 is used to evaluate and control the individual components. A socket 138 can provide a pluggable connection to the outside and / or a connection to the recirculation unit 200.

[0060] Sealing lips 134 are shown in Figure 17. These are attached to the cover plate 105. (Alternatively, an arrangement on the slides is also conceivable.) The sealing lips are particularly important for small air opening settings and when completely closed. The sealing lips 134 are therefore also particularly important with regard to the determination of aw values, as explained later in the context of aw measurement cycles. Without the sealing lips, the measurement runs the risk of producing a falsified aw measurement result. A significant systematic measurement error in the measured aw value can thus be reduced to a minimum by the sealing lips. For example, an optical signal can be transmitted via an opening 135, which is particularly suitable for signal transmission from the fill level sensor of the drain pan in the embodiment shown.

[0061] Figure 19 shows exposed electrical contacts 139b. A conductivity measurement detects the presence of liquid. An optical signal, for example, can then be emitted and measured by photodiode 139.

[0062] The granule measuring arm 141 rests on the granule 142 and thereby measures the granule level 140. The angle change of the measuring arm 141 also moves the gray scale 113, which is measured by the reflex light barrier 112 arranged on the PCB 114. The overflow opening 144 (Figure 20) in the granule tray 106 prevents overflow of the collecting tray 108 if the drain openings provided in the bottom of the tray 106 become clogged or are otherwise prevented from functioning properly.

[0063] Figure 23 shows an exemplary ultrasonic humidifier 101 (US humidification unit 101) in cross-section. The US humidifier 101 can be connected to a drying unit 100 via a cable 180 and attached there with the holder 182. A level gauge 183 with an internal, magnetically triggered reed contact ensures that the US humidifier 101 is sufficiently filled. The float 185 is equipped with an internal magnet for triggering the reed contact. A lock nut 184 ensures that the level gauge is held and particularly securely seated. The upper part 184 contains the sono unit (microperforated disc), as well as a centrally arranged outlet opening 186 for the atomized liquid.

[0064] Figures 25 and 26 show further illustrative exploded views in order to better understand and comprehend the spatial geometry and functioning of the drying unit in the context of this embodiment.

[0065] Figures 27-30 show exemplary exploded views of a pluggable external unit 208 and the screw connection of the recirculation unit to the cover wall 218. The external unit 208 can have a display 216 and / or a control pad 215. The hermetic seal of the screw connection (external screw connection 217a with internal screw connection 217b) is achieved by the cast-in and / or glued circuit board 214 on the one hand and the silicone flat seals 212a, 212b on both sides on the other hand.

[0066] Figure 31 illustrates an exemplary visualization of a drying process and the course of an exemplary aw value (water activity).

[0067] Phase 1 begins with loading fresh material. There is a lot of water on the outside, the outer area of ​​the material is moist, and the core area is very moist. The aw value (water activity of the material to be dried) is close to 1. In Phase 1, the surface water is removed by rapid drying, and the aw value decreases. Phase 2 is desired to be reached quickly to minimize the risk of mold / rot. In Phase 2, water from the outer area penetrates to the surface of the material to be dried. The aw value continues to decrease. Drying slows down somewhat. In Phase 3, excess moisture is removed from the core area, which takes longer. In Phase 4, the moisture levels equalize; at the end, drying is complete, and the product can be stabilized at the "perfect" (i.e., desired) aw value.

[0068] The aw value determines how much water on product surfaces is freely available to microorganisms, among other things. There are threshold values ​​below which the growth of mold and other pathogens is largely inhibited.

[0069] The flowchart of Figures 32 - 35 illustrates an exemplary operating procedure ("(main) drying program") for a drying unit 100 in a drying container 300. (Some longer labels can be found in the list of reference symbols.)

[0070] The essentially self-explanatory diagrams have merely been expanded with a few additional notes. The control method can be based on the calculation of absolute target and / or incremental values, or essentially (shown here) operate incrementally, based on regular execution. This allows for subsequent corrections, particularly with regard to new, small changes, thus creating a stable drying and / or curing process. Various modes can be provided, including various programs, the latter of which can each contain a (“real”) drying mode and a curing mode (for quality-assured storage). The curing mode, in particular, is designed to be particularly energy-efficient. The device can thus be operated for long periods using, for example, just a commercially available (USB) power bank as the power supply, which is advantageous for mobility and logistics – among other things.also travel, especially in the private non-commercial sector - is advantageous.

[0071] An example cycle time is 60 seconds. The RH setpoint is the desired, adjustable relative humidity in the container (corresponding, in a sense, to the more important target aw value of the product, using the relationship: aw = RH / 100% in equilibrium).

[0072] The flowchart in Figure 36 illustrates an aw value measurement cycle as well as an extended evaluation / control of the drying process by taking the aw value (specific water activity) into account. For an aw measurement cycle (determination of the specific water activity), for example, the drying program can be interrupted or temporarily suspended.

[0073] The aw value essentially determines how much water is freely available on the surfaces of products, for example for microorganisms.

[0074] In the embodiment of the present invention discussed here, the determination of the aw value is possible during the ongoing process: at regular intervals, the drying process is interrupted and the value to which the humidity rises is measured (with a time limit, a measurement is not carried out for an indefinite period, especially in the early phases to avoid the risk of mold / rot; a mathematical extrapolation method can be used to further reduce the time).

[0075] This is advantageous compared to regular sampling to determine the current aw value (state-of-the-art, frequently used in the food processing industry). A sample of the product is taken, placed in a hermetically sealed container, and the humidity is continuously measured.

[0076] The direct determination according to the invention is more precise and reduces interference with the drying process caused by the otherwise required hermetic breakthrough. Thus, using a suitable operating procedure and evaluation, the aw value can be determined regularly and used to further optimize the drying process.

[0077] Additional parameters can be determined in the aw measurement cycle, and corresponding control parameters for the drying program can be reset and / or modified. Separate measuring equipment is not required.

[0078] For example, a main drying process can be interrupted after a regular time interval for an aw measurement cycle. This can occur every 2–4 hours, for example. With this method, a maximum fan speed n(maxdyn) and a maximum opening angle w(maxdyn) for dampers can also be dynamically recalculated, which is particularly advantageous for achieving particularly gentle yet efficient drying within the main drying program (see Figs. 32–35). Thus, the aw measurement cycle has an additional dynamic impact on the operation of the main program through the aforementioned variables.

[0079] Through this feedback, the level of external humidity (see also Fig. 31) is deliberately taken into account in a particularly appropriate manner. Loosely speaking, drying is advantageously more "accurate" if there is still too much humidity outside, but more gentle and even if this has already been reduced or the level is acceptable.

[0080] For example, a measurement taken during drying may reveal that there is still too much moisture outside (high gradient - rapid increase in RH (relative humidity) in the container within a short period of time). In this case, the drying process is more intensive between measurements, as a higher speed of the dehumidifier fan and a larger opening angle of the dampers can remove more moisture. Conversely (low gradient) the drying process is reversed. The goal is more even drying while observing the aw value. This value adjusts throughout the entire drying phase and returns to the value set by the user towards the end (and is then maintained).

[0081] During the drying phase, these values ​​can be "overwritten" by the calculated new maximum values ​​influenced by the previous aw measurement cycle and remain valid until the next measurement cycle. Therefore, due to an increase in the temporal development of relative humidity, an adjustment of the values, particularly n(maxdyn) and / or w(maxdyn), of the (main) drying program is made.

[0082] As an important clarification, it should be noted: Within the scope of an aw measuring cycle and Figure 36, rFZiel refers to a variable internal to the measuring cycle, without any effect on an rF setpoint of the main program.

[0083] Particularly important steps in the functioning of the aw measurement cycle are roughly outlined below:

[0084] Steps 1001 and 1002 essentially aim to record a starting relative humidity (67% in Fig. 40). Subsequently, a gradient determination takes place for each step size (change in relative humidity; 5% in Fig. 40). This is determined by steps 1004 and 1005; the gradient determination itself takes place in step 1007. In step 1008, the subsequent RH step size (for the next gradient determination) is regularly started. If a termination condition is reached (gradient falls below the minimum threshold, Yes in step 1007), the aw measurement cycle is terminated. Furthermore, if a maximum measurement time is reached (step 1006), the process can continue with step 1007 (evaluation of the termination condition).

[0085] The relative humidity at the end of the measurement can be used as a very good approximation as the aw value (step 1009). The maximum gradient of a measurement cycle, m(max), can also be used to reset control values ​​of the main program, such as n(maxdyn) and / or w(maxdyn) (steps 1010 and 1011).

[0086] The measurement cycle is now complete. You can return to the (main) drying program.

[0087] For a detailed understanding based on an example, please refer to Figures 39 and 40 and the relevant discussion.

[0088] In one example, a drying process is started by a user (especially for the first time). For example, certain values ​​for a maximum fan speed n(max) for the dehumidification fan and / or for a maximum opening angle of one or more dampers w(max) are preset by user configuration (or certain default values) (e.g., n(max)=80%, w(max)=100%). The values ​​can be configured as absolute or relative (%) values.

[0089] In an example first aw measurement cycle (the first during the drying of a new "batch" of dry material), a maximum gradient of 0.61 was numerically determined during the measurement cycle m(max) of 0.61. This indicates that the surface moisture content is still very high. After the first measurement cycle, n(maxdyn) is recalculated based on this value. This results, for example, in: n(maxdyn) = 1.1*n(max)=88%. For example, w(maxdyn) remains at 100% (since 100% is already the absolute "maximum value" [sic!]). After, for example, 9 further measurement cycles, a maximum gradient of 0.23 in the relative humidity in this cycle was determined in a 10th measurement cycle. To ensure gentle and even drying, the following calculation is now made for the subsequent drying process at this advanced stage of drying: n(maxdyn) = 0.7*n(max) = 56%, w(maxdyn) = 0.7*w(max) = 70%.

[0090] Calculations of the form n(maxdyn) = n(max) * (m(max) / m(ref) * k1) and w(maxdyn) = w(max) * (m(max) / m(ref) * k2) take into account the effects of moisture gradients in the product during the drying process. m(ref) is a normalization / calibration to the first aw measurement cycle during drying. k1 and k2 are adjustable correction factors. These can depend on the type and / or properties of the material to be dried or can be adjusted. In particular, properties of the material with regard to the internal water / moisture diffusion properties are relevant (e.g. response to a specific moisture gradient) and can be adjusted accordingly using k1 and k2.

[0091] In addition, new drying processes / algorithms can even be implemented via online updates. This doesn't even require opening the vessel or breaking the hermetic seal.

[0092] Figure 37 illustrates another exemplary, advantageous drying model. The model is based on a saturation deficit (VPD = vapor pressure deficit). This model is also easy to implement: The temperature is constantly measured anyway, and the humidity can be varied via the drying unit.

[0093] Figure 38 shows some curves, each with a constant VPD, for exemplary VPD-based drying processes (plot: relative humidity as a function of temperature). This process achieves particularly desirable results for certain dry goods. Drying at a constant VPD can keep the moisture gradient within the product (i.e., from the surface to the "core") as small as possible. This makes drying particularly gentle. In particular, the aw value (at the surface) can be kept below a critical value (e.g., a critical value of 0.65). For some VPD drying processes, temperature control and / or means for raising and / or lowering the temperature may be provided.

[0094] Figures 39 and 40 illustrate further exemplary properties related to a (multiple repeated) aw value determination. Figure 39, the upper graphic, illustrates an exemplary measurement cycle: Details of this example can be found in Figure 40. Figure 39, the lower graphic, illustrates the course of a "maximum gradient" m(max) over a drying process comprising several aw measurement cycles. The main drying process can, for example, be interrupted after a regular time interval for an aw measurement cycle. This can occur every 2–4 hours, for example.

[0095] Optionally, a UV air disinfection unit can be added to the drying unit. This unit can be used for dried goods that are particularly prone to mold and / or rot, as it can suppress pathogens. However, for most common plant materials, this additional suppression of mold and / or rot is no longer necessary when using the invention.

[0096] List of reference symbols

[0097] 100 drying units

[0098] 101 Ultrasonic Humidifier (removable)

[0099] 102a,b connector (connects the sliders)

[0100] 103 Motor (drive for 2nd slide 104b,

[0101] Stepper motor with flanged gear for adjusting the slides)

[0102] 104a, b slide valve (a=1=air inlet, b=2=air outlet)

[0103] 105 Cover plate for granulate tray (is the carrier for components)

[0104] 106 Granule tray with drainage holes (filled with desiccant)

[0105] 107 Level sensor for collecting tray

[0106] 108 Liquid collection tray

[0107] 110 Fan / Fan 1 (variable speed)

[0108] (sucks in air, blows it out through four closable inlet openings via a desiccant and through the two outlet openings)

[0109] 111 Stepper motor mount (belonging to the 2nd slider)

[0110] 112 Reflex light barrier (directed to gray scale)

[0111] 113 Guided rod with gray scale

[0112] 113b Guide for grayscale

[0113] 114 Circuit board (PCB), for the mechanical mounting of the light barriers and for the electrical distribution of the signals

[0114] 115 Light-tight cover for reflex light barrier to minimize external influences (ambient light)

[0115] 116 Fork light barrier, for determining the reference position (zero position) of the slider

[0116] 117 Holder for stepper motor; also: guide for gray scale of granulate level arm; holder for circuit board for connecting motor, fan 1, light barriers 120 Recess in slide 2 (air outlet)

[0117] 121 Recess in the cover plate 105

[0118] 122 Recess in slide 1 (air inlet)

[0119] 130 First housing part cover top

[0120] 130b Air inlet / inlet openings

[0121] 131 Second housing part cover at the top, with sockets for connecting cables to the humidifier and the recirculation unit (upper unit), with WiFi and Bluetooth-enabled microcontroller for evaluation and control of the individual components

[0122] 131b Air outlet / outlet openings

[0123] 132 Lower housing cover

[0124] 133 Holder for the US humidifier (removable)

[0125] 134 Sealing lip in cover plate, seals the opening in the cover plate against the slide and reduces unwanted dehumidification in storage mode

[0126] 135 Opening for optical signal from level sensor drain pan

[0127] 136 Level sensor for dissolved desiccant (saline solution)

[0128] 137 WiFi and Bluetooth-enabled microcontroller for evaluation and control of the individual components

[0129] 138 Socket for plug-in connection of the connecting cable (from drying unit to recirculation unit)

[0130] 139 Receiver (photodiode) for signal from liquid sensor, gives an electrical signal when light is received from the liquid sensor

[0131] 139b Exposed contacts, conductivity of a contacting liquid is detected

[0132] 140 granulate level (chemical dehumidifier level)

[0133] 141 Granule measuring arm

[0134] (arm resting on granulate, rotatable around an axis, which can move a guided gray scale vertically, angle changes with the height of the granulate)

[0135] 142 granules

[0136] 143 Desiccant liquefied by humidity (saline solution) 144 Overflow openings for dissolved desiccant (if lower openings become blocked, it can flow into the drip tray)

[0137] 180 connecting cable for connecting the ultrasonic humidifier to the drying unit

[0138] 181 upper part with sono unit (micro-perforated disc) and electronics

[0139] 182 Holder of the humidification unit for insertion into the counterpart on the fan holder of the drying unit

[0140] 183 Level gauge with internal reed contact (magnetically triggered)

[0141] 184 Lock nut for level dipstick

[0142] 185 Float with internal magnet; triggers reed contact as soon as a certain level is exceeded

[0143] 186 Outlet opening for atomized water

[0144] 200 recirculation unit

[0145] 201 Counterpiece / holder with thread and seal

[0146] (is screwed through the wall with the fan bracket)

[0147] 202 Fan bracket / recirculation unit bracket

[0148] 203 Recirculation fan (fan / fan 2)

[0149] 204 Recording of part of the control electronics with humidity and temperature sensor

[0150] 205 Connection cable drying unit (lower unit) and recirculation unit (upper unit)

[0151] 206 Humidity and temperature sensor

[0152] 207 Screw connection with internal and external flat seal, for hermetically sealing the opening

[0153] 208 Replaceable outdoor unit (pluggable attachment); option for power supply only (via standardized USB-C socket or optionally with USB-C socket for power supply and integrated display with control buttons)

[0154] 208b Replaceable outdoor unit (plug-in attachment); variant only

[0155] Power supply

[0156] 209 USB-C socket (see also 208)

[0157] 210 Lid of the vessel / drying container

[0158] (with hole for screwing the outdoor unit) 211a User Interface (display and control buttons) + power supply

[0159] 211b power supply (UL control via software / app)

[0160] 212a Flat gasket outside

[0161] 212b Flat gasket inside

[0162] 213 Cover of the screw connection including holder 204

[0163] 214 Board glued / potted into external screw connection with connectors on both sides; ensures that the dry area is sealed against the environment (hermetic)

[0164] 215 D-pad

[0165] 216 Display

[0166] 217a External screw connection, with external thread and holder for circuit board with connectors

[0167] 217b Internal screw connection, with internal thread

[0168] 218 Housing / vessel wall with through hole

[0169] 219 Board for connectors, buttons, display

[0170] 220 connectors (various)

[0171] 300 Dry container (hermetically sealable) e.g. for storing dry goods in bags (or similar)

[0172] 301 Clip for hooking / attaching the bag to the container

[0173] 302 Air-permeable bag / sack for the collection of dry goods (shown as an example, several of them are possible)

[0174] 303 Clamping ring for vessel and lid

[0175] 905 User input process parameters: max. fan speeds, max.

[0176] Opening angle of the dampers, cycle times (time between measurements and adjustment of dehumidification / humidification), type of drying (strong, medium, weak), step sizes for fans and dampers between adjustments, setpoint for relative humidity, hysteresis for setpoint

[0177] 934 Circulation fan on MAX, spray water mist to

[0178] Increase in humidity, waiting time, no process, distribution of humidity and avoidance of false measured values, after waiting time reset the speed of the recirculation fan to the original value

[0179] 1010 The largest gradient of the measurement cycle (m(max)) is saved along with a consecutive number. The largest gradient of the first measurement cycle is saved as m(ref) as a starting value for further calculations. Gradients in relative humidity should decrease continuously from measurement to measurement (checking the drying process and optimizing the process is possible). 1011 Dynamic adjustment of dehumidification (max. fan speed n(maxdyn) of the dehumidification fan from a specified max.

[0180] Fan speed n(max) derived; max. opening angle w(maxdyn) of the slider), weighting of the adjustment via modifiable correction factors k1 and k2, example calculation: n(maxdyn) = n(max) * (m(max) / m(ref) * k1) w(maxdyn) = w(max) * (m(max) / m(ref) * k2)

[0181] These dynamic maximum values ​​are used as current maximum values ​​between the measuring cycles for the fan speed and the maximum opening angle of the dampers

Claims

Patent claims 1. Drying unit (100) for use in a drying container (300) for the gentle drying of organic, in particular plant, material, which is designed to remove moisture from the circulating air on the basis of chemical dehumidification by means of a chemical dehumidifier (142), wherein an intensity of the chemical dehumidification is designed to be controllable.

2. Drying unit (100) according to claim 1, comprising a control system with which the intensity of the chemical dehumidification is controlled over time.

3. Drying unit (100) according to claim 1 or 2, wherein a control of an intensity of the dehumidification is effected by adjusting and / or influencing an intensity of an air flow in the region of a chemical dehumidifier (142).

4. Dryness (100) according to one of the preceding claims for use in a drying and / or storage vessel (300), in particular a hermetically sealable vessel (300).

5. Dryness (100) according to one of the preceding claims, further comprising means (203) for generating a circulating air circulation, in particular in a drying area which is intended for material to be dried and / or stored.

6. Drying unit (100) according to claim 5, wherein the drying area is arranged between the means (203) for generating a circulating air circulation and a chemical dehumidification area (106).

7. Drying unit (100) according to claim 5 or 6, wherein the means (203) for generating a circulating air circulation are designed so as to be controllable in their intensity, in particular as a speed-controllable fan (203).

8. Drying unit (100) according to one of the preceding claims, comprising a tray (106) for receiving desiccant, in particular a tray (106) with drainage openings.

9. Drying unit (100) according to one of the preceding claims, comprising a region (106) of a drying agent (142), in particular in a tray (106), wherein the drying unit (100) further comprises inflow openings (121) and outflow openings (121) for air, which are designed to allow air to flow into or out of the region of a drying agent, in particular inflow openings and / or outflow openings in a cover of the tray (106).

10. Drying unit (100) according to claim 9, further comprising at least one slider (104a, b) which at least partially covers an inlet or outlet opening (121), and whose relative movement to the inlet or outlet opening (121) is suitable for regulating an air flow through the inlet and / or outlet opening.

11. Drying unit (100) according to one of the preceding claims, comprising an air inlet slide (104a) which is suitable for regulating an air flow through an inlet opening and / or an air outlet slide (104b) which is suitable for regulating an air flow through an outlet opening.

12. Drying unit (100) according to one of the preceding claims, comprising at least one slide (104a, b) which itself has air flow openings (120, 122), in particular alternating areas of air flow openings (120, 122) and closed areas.

13. Drying unit (100) according to one of the preceding claims, comprising at least two slides (104a, b) for regulating air flows, in particular an inlet air flow and an outlet air flow.

14. Drying unit (100) according to claim 13, wherein at least two slides (104a, b) are mechanically coupled to one another by at least one connector (102a, b), in particular two connectors (102a, b).

15. Drying unit (100) according to one of claims 10 - 14, wherein at least one slide (104a, b) is designed as a rotary slide (104a, b), in particular two slides (104a, b) are designed as rotary slides (104a, b), in particular two slides (104a, b) which are connected by at least one connector (102a, b), in particular two connectors (102a, b), and are designed as rotary slides (104a, b).

16. Drying unit (100) according to one of claims 10 - 15, comprising a light barrier, in particular a fork light barrier (116), for calibrating a relative position of at least one slider (104b), in particular a zero position of at least one slider (104b).

17. Drying unit (100) according to one of the preceding claims, comprising a granulate measuring arm (141) for detecting a fill level of a chemical dehumidifier (142).

18. Drying unit (100) according to claim 16, wherein the granulate measuring arm (141) interacts mechanically with a guided rod (113), in particular a rod with a scale, in particular an optical scale, in particular a gray and / or color scale (113).

19. Drying unit (100) according to claim 16 or 17, wherein a fill level and / or an angular deflection of the granulate measuring arm (141) can be determined on the basis of an evaluation, in particular a scale, by means of a light barrier, in particular a reflex light barrier (112).

20. Drying unit (100) according to one of the preceding claims, further comprising a collecting tray (108) for dissolved chemical dehumidifier (142, 143).

21. Drying unit (100) according to claim 20, further comprising a conductivity detector (136) and / or liquid sensor (136), in particular arranged on the underside of the tray (106) and / or an area (106) designed to receive desiccant, in particular in an upper area of ​​the collecting tray (108).

22. Drying unit (100) according to claim 21, wherein the conductivity detector (136) and / or liquid sensor (136) generates an optical signal when triggered.

23. Drying unit (100) according to claim 22, wherein the optical signal is detected by an optical signal receiver (139), in particular a photodiode (139), in particular photodiode (139) arranged in a region above a region (106) designed to receive desiccant, in particular the tray (106), in particular photodiode (139), which is a circuit board and / or a PCB (114) with one or more light barriers, in particular with a fork light barrier (116) and / or a reflex light barrier (112).

24. Drying unit (100) according to one of the preceding claims, further comprising an ultrasonic humidifier (101), in particular configured to increase and / or prevent a decrease in air humidity by the controlled release of water vapor, in particular to counteract a decrease in air humidity, for example below a target value, during longer storage and / or curing processes.

25. Drying unit (100) according to claim 24, wherein the ultrasonic humidifier (101) comprises a magnetically triggered reed contact (183, 185).

26. Dryness (100) according to one of the preceding claims, further comprising a drying and / or storage vessel (300), in particular a hermetically sealable vessel (300, 210, 214).

27. A method for operating and controlling a drying unit (100) for use in a drying container (300) for gently drying organic, in particular plant, material, in particular a drying unit (100) according to one of the preceding claims, based on chemical dehumidification by means of a chemical dehumidifier (142) in a drying container (300), in particular a hermetically sealed and / or sealable drying container (300), comprising Measuring (908) measured values ​​of a temperature and / or a humidity in the drying container (300), and Controlling an effective contact of circulating air in the drying container (300) with the chemical dehumidifier, in particular by changing a speed of a ventilation device (110) and / or by effectively changing ventilation inlets (120 - 122), on the basis of at least one of the measured values.

28. The method of claim 27, further comprising Measuring (1009) a current aw value of the dry material in the drying container (300) without having to open the drying container (300).

29. The method according to claim 27 or 28, wherein a new drying and / or curing algorithm can be executed without having to open the drying container (300).

30. The method according to any one of claims 27-29, further comprising: Setting a humidity setpoint based on a VPD and / or saturation deficit.

31. The method according to any one of claims 27-30, further comprising: Varying, in particular periodically varying, and / or modulating, in particular periodically modulating, in particular also with constant environmental factors, measured values ​​and / or setpoints, an effectiveness of a recirculation unit (203), in particular a speed of a fan (203), for recirculating air in the drying container (300), in particular between a maximum speed and a minimum speed.

32. The method according to any one of claims 27-31, further comprising: Controlling an ultrasonic humidifier (101) to increase and / or prevent a decrease in air humidity by the controlled release of water mist and / or atomized water, in particular to counteract a decrease in air humidity, for example below a target value, during longer storage and / or curing processes.

33. Method according to one of claims 27 - 32, comprising Repeated measurement (1004) of a humidity, in particular within the scope of a measurement cycle and / or with deactivated chemical dehumidification, Calculating (1007) at least one gradient of a temporal development of the measured air humidity, Adjusting (1011) a control parameter for a subsequent drying process based on the at least one gradient.

34. The method of claim 33, comprising: Calculating (1007) at least one gradient of a temporal development of the measured air humidity for each interval of several intervals, which are formed by a starting humidity and a target humidity (1002), Calculating and / or selecting (1010) a maximum gradient value from the calculated gradients, Adjusting (1011) a control parameter for a subsequent drying process based on the maximum gradient value.

35. Method according to claim 33 or 34, wherein at least one control parameter for a subsequent drying process comprises one or more of: a maximum fan speed, as a relative value or absolute, in particular for a dehumidification fan (110), and / or a maximum effective opening (120 - 122), as a relative value or absolute, of an air supply (120 - 122) to a chemical dehumidifier (142), in particular a maximum opening angle, as a relative value or absolute, of at least one slider (104a, b) for adjusting such an opening.

36. Organic dry material, in particular vegetable dry material, dried by means of the drying unit (300) according to one of claims 1 - 26 and / or obtained by the method according to one of claims 27 - 35.

37. A computer, processor, data processing device, microprocessor or computer component which is configured to effect the method according to any one of claims 27-35 and / or is configured to control a drying unit (300) according to any one of claims 1-26.

38. A computer program or computer-readable storage medium which, when executed, is suitable for effecting the method according to any one of claims 27 to 35 and / or is arranged, when executed, to control a drying unit (300) according to any one of claims 1 to 26.

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