Gas dryer device of the multi-tower cartridge type, particularly for an apparatus for dehumidifying granular materials and method for regenerating a cartridge of a gas dryer device

Abstract

A gas dryer device (1) of the multi-tower cartridge type, comprises a central member (10) in which cartridges (12a, 12b, 12c, 12d) with gas-drying material are housed, a first and a second head (20, 30) positioned at the axially opposite ends of the central member, and a first and a second seal (61, 62) interposed between the heads (20, 21) and the central member (10). The device further comprises a movement system (40) configured to reversibly move at least one of the heads (20, 30) between an operating configuration (CO), in which the heads (20, 30) are coupled in a fluid-tight manner to the central member (10) and respectively placed at a first and second minimum distance (Dm1, Dm2) from said central member (10), and a rotational configuration (CR) in which at least one of the heads is displaced from the central member at a rotational actuation distance (Da1, Da2) greater than the distance at which it is located in the operating configuration. The device also includes a drive system (50) configured to rotate the central member (10) in steps with respect to the heads when the heads (20, 30) are moved into the rotational configuration (CR).

Description

[0001] GAS DRYER. DEVICE OF THE MULTI-TOWER CARTRIDGE TYPE, PARTICULARLY FOR AN APPARATUS FOR DEHUMIDIFYING GRANULAR MATERIALS AND METHOD FOR REGENERATING A CARTRIDGE OF A GAS DRYER DEVICE

[0002] Technical area

[0003] The present invention relates to a gas dryer device of the multi-tower cartridge type, comprising the features set out in the preamble to the main claim. The invention also concerns a granular material dehumidification apparatus comprising such a gas dryer device, as well as a method for regenerating a cartridge of a gas dryer device.

[0004]

[0005] In the general area of industrial processing of material in granular form, dehumidification of such material is often required.

[0006] Examples of such processing can be found in the plastics processing industry (polymer granules or additives), in the food industry (seeds, grains, cereal flakes) and in the chemical industry (chemicals, additives, etc.).

[0007] In the following, reference will be made to polymer-based granular materials, in particular thermoplastic polymers, intended for processing by moulding or extrusion, without losing generality.

[0008] It is specified that 'granular material' means a material composed of a plurality of distinct and separate solid elements, having dimensions and shapes appropriate to the processing to be carried out and to the polymer material used, including polymer material in powder or flake form. Such material is also generally identified as 'bulk material' or 'free-flowing material'.

[0009] In the processing of polymer materials, it is well known that it is important to carry out certain processing steps, such as extrusion and moulding, with polymer granules or pellets having very low moisture content, as excessive moisture in the granules can cause serious defects in the end products obtained from the process.Therefore, it is known to provide, upstream of processing steps such as extrusion or moulding, for the dehumidification of the polymer granules, wherein the latter are kept inside a hopper traversed by a flow of dry and hot gas (typically air).

[0010] In this technological context, various embodiments envisage treating the gas to be fed into the dehumidification hopper of the polymer granules by means of a dryer device specifically designed to reduce the moisture content of the gas by passing it through cartridges (or drums) containing within them a suitable desiccant material capable of adsorbing the water present in the gas, e.g. molecular sieves.

[0011] Such dryer devices typically comprise a plurality of cartridges, which can be rotated between different stations so that, while one cartridge is passed through the gas to be dried, adsorbing its moisture, another cartridge, already saturated (or nearly saturated) with moisture, is subjected to a step of regenerating desiccant material, so that it is again suitable for removing moisture from the gas to be treated.

[0012] In particular, dryer devices are known to comprise a cylindrical body (rotor element) in which the different cartridges are housed, interposed between two heads (stator elements), which group the passage ducts of the various gas flows involved and define the different operating positions of the cartridges, in which the cylindrical body is rotated to move the cartridges between the different positions defined in the heads, which, on the other hand, remain fixed.

[0013] This solution involves programmed rotation of the cartridges according to the level of saturation they reach during normal operation so that they can be used advantageously, time after time, under the best operating conditions.

[0014] An example of such a dryer device is described in patent document CN 105202877 in which cartridges, containing molecular sieves, are moved between the different stations with a discontinuous (step) rotation motion.

[0015] In other dryer devices, however, the rotation of the cylindrical body with respect to the heads is expected to be continuous.The Applicant noted, however, that such a rotational movement produces, due to the rubbing that occurs during rotation, undesirable and significant wear of the seals interposed between the rotor central member and the heads.

[0016] Following numerous and targeted studies, the Applicant realised that such seal wear leads to several complications in the management and optimisation of the moisture control process of the polymer granules in the hopper.

[0017] In fact, wear on the seals can lead to loss of their ability to ensure a fluid-tight coupling between the heads and the cylindrical member.

[0018] As a result, a first problem becomes apparent in the continuous loss of process gas, which is released in an uncontrolled and undesirable way into the environment.

[0019] The Applicant also noted that resolving this non-ideal operating condition by bringing the stator closer to the rotor so as to bring the interposed seals to a higher compression condition can, on the one hand, achieve a greater seal of the dryer device, but on the other hand also inevitably implies greater friction on the seals during the rotation steps with consequent further impairment of the process conditions.

[0020] Further, the Applicant found that this inefficient operating situation leads to a more frequent need for replacement of the rapidly worn seals, necessarily requiring a shutdown of the dryer during such intervention stages and thus also reducing the overall performance of the process concerned.

[0021] What's more, the Applicant noted that these operations for replacing worn out seals require long shutdown times of the dryer and also entail the possibility of dust or dirt being deposited on the cartridges, risking reducing their operating performance.

[0022] The Applicant also pointed out that the same type of problem arises when it is necessary to replace one or more cartridges, as it becomes necessary to stop the dryer and remove the stator from the rotor in order to be able to remove the cartridges to be replaced.As can be clearly understood, this condition makes the system not particularly efficient and unsuitable for many processes where it is essential to limit variations in the parameters of the dried gas as much as possible and to maintain a high and essentially constant process yield.

[0023] Description of the invention

[0024] The technical problem underlying the present invention is to make available a gas dryer device, in particular of the multi-tower cartridge type, as well as a method for regenerating a cartridge of a dryer device that is structurally and functionally designed to overcome, at least in part, the drawbacks complained of with reference to the aforementioned prior art.

[0025] In particular, a purpose of the present invention is, for example, to provide a gas dryer device, especially suitable for operating in a granular material dehumidification apparatus, which can increase the consistency of the performance of the granular material dehumidification process, reduce the wear of the components during the operating steps, thereby also limiting the frequency of their replacement, and, at the same time, facilitate any cartridge replacement steps.

[0026] This problem is solved, and this and other purposes are achieved by the invention by means of a gas dryer device of the multi-tower cartridge type and a method for regenerating a cartridge of said dryer device, made according to the appended claims. In a first aspect thereof, the present invention is thus directed to a gas dryer device, of the multi-tower cartridge type, comprising a central member in which a plurality of housings configured to accommodate a respective plurality of cartridges each comprising a desiccant material capable of drying the gas is defined.

[0027] Preferably, the central member extends along one a longitudinal axis thereof.

[0028] Preferably, the dryer device comprises a first head and a second head positioned at the axially opposite ends of the central member.

[0029] Preferably, the first head comprises a first plurality of pipes of a process circuitconfigured to pass gas through a first cartridge, to dry the gas, and a regeneration circuit, configured to regenerate a second cartridge.

[0030] Preferably, the second head comprises a second plurality of process circuit and regeneration circuit pipes.

[0031] Preferably, the dryer device comprises a first seal interposed between the first head and the central member and configured to bring about a fluid-tight coupling between the first head and the central member.

[0032] Preferably, the dryer device comprises a second seal interposed between the second head and the central member and configured to bring about a fluid-tight coupling between the second head and the central member.

[0033] Preferably, the dryer comprises a movement system connected to the first and / or second head and configured to move reversibly along the longitudinal axis at least one of the first or second head between

[0034] o an operating configuration, in which the first and second heads are coupled in a fluid-tight manner to the central member and placed at a first and second minimum distance from the central member respectively, and

[0035] o a rotational configuration in which at least one of the first or second heads is displaced from the central member at a first or second rotational actuation distance greater than the first or second minimum distance.

[0036] Preferably, the dryer device comprises a drive system secured to the central member and configured to rotate the central member in steps about the longitudinal axis when the first and / or second head(s) is / are moved into the rotational configuration.

[0037] Thanks to this technical solution, it is possible to selectively divide the moments when the central member is stationary and coupled in a fluid-tight manner to the first and second heads, and thus in the optimal condition for the gas drying process concerned, and the moments when at least one head is further away from the central member, and thus the central member can be rotated to move the cartridges between theprocess circuit and the regeneration circuit without causing excessive wear to the seals.

[0038] Furthermore, the Applicant has noted that with this technical solution, it is possible to manage in a more controlled and precise manner any change in tightness due to, for example, wear and tear or other reasons by advantageously varying and adapting the value of the minimum distance and / or the value of the rotational actuation distance on a case-by-case basis.

[0039] Reduced wear also means less need for replacement of sealing elements, increasing the life and reliability of the device and thus increasing the overall efficiency of the process involved.

[0040] Again, the Applicant also noted that being able to selectively distance the first and / or second head of the central member also made seal and / or cartridge replacement operations faster and more efficient.

[0041] In a second aspect thereof, the invention concerns an apparatus for dehumidifying materials, for example polymer-based granular materials, comprising a hopper containing a material to be dehumidified.

[0042] Preferably, the apparatus comprises a process circuit connected to the hopper to introduce a dry gas into the hopper in order to dehumidify the material contained therein.

[0043] Preferably, the process circuit comprises a dryer device configured to dry the gas to be introduced into the hopper.

[0044] Preferably, the dryer device is made in accordance with the first aspect of the present invention.

[0045] With this technical solution it is possible to provide a material dehumidification apparatus in which the drying gas passing through the hopper containing material maintains its characteristics more constantly and reliably, advantageously increasing the efficiency of the dehumidification apparatus.In a third aspect thereof, the invention concerns a method for regenerating a cartridge of a gas dryer device of the multi-tower cartridge type.

[0046] Preferably, the method comprises the arrangement of a dryer device made according to the first aspect of the present invention.

[0047] Preferably, the method comprises activating the movement system by moving at least one of the first and second heads from the operating configuration to the rotational configuration.

[0048] Preferably, the method involves rotating the central member by means of the drive system while the first and / or second head is in the rotational configuration, bringing the first cartridge in place of the second cartridge.

[0049] Preferably, the method comprises activating the movement system by restoring the operating configuration.

[0050] Preferably, the method comprises activating a regeneration process for the first cartridge.

[0051] In this way, it is possible to move a desired cartridge into a regeneration circuit, significantly reducing wear on the sealing elements concerned.

[0052] In a fourth aspect thereof, the invention concerns a method for replacing a cartridge of a gas dryer device of the multi-tower cartridge type.

[0053] Preferably, the method comprises the arrangement of a dryer device made according to the first aspect of the present invention.

[0054] Preferably, the method comprises activating the movement system to move at least one of the first and second heads from the operating configuration to the rotational configuration.

[0055] Preferably, when the first and / or second head of the dryer device are moved into the rotational configuration:

[0056] the first seal is spaced apart from the first head or central member, or the second seal is spaced apart from the second head or central member,thus defining an uncoupling configuration between the first or second head and the central member.

[0057] Preferably, the method comprises replacing the cartridge in the respective seat.

[0058] Preferably, the method comprises activating the movement system to restore the operating configuration.

[0059] Thanks to the possibility of quickly detaching the cartridges, or at least one of them, from the central member, the cartridges housed in the respective seats are made immediately available and those to be replaced can be easily removed by an operator to be replaced with new cartridges.

[0060] It will thus be appreciated that the dryer device of the present invention avoids the complex and costly disassembly of the heads from the central member and, possibly, the cartridges from the central member.

[0061] In one or more of the above aspects, the present invention may comprise one or more of the preferred features described below.

[0062] In some embodiments, the minimum distance between the central member and the first and / or second head is essentially zero.

[0063] In other words, it is intended that the heads are brought into abutment with the central member, with the first and second seals housed in a respective seat, e.g. on the central member, compressed between the central member and the heads.

[0064] Preferably, the movement system comprises at least one pneumatic or electric or magnetic actuator.

[0065] Thanks to this technical solution, the displacement of the first and / or second head in relation to the central member can be performed in an effective and constructively simple manner.

[0066] In some embodiments, the at least one pneumatic or electric actuator comprises at least one piston, and preferably two or more pistons, of the single-stroke pneumaticor electric type configured to move the first and / or second head from the operating configuration to the rotational configuration.

[0067] Preferably, the movement system comprises a first and second elastic element configured to move the first and second head respectively in the operating configuration.

[0068] This allows selectively precise and effective control of the implementation of the rotational configuration and rapid return to the operating configuration.

[0069] Furthermore, this embodiment ensures that in the event of a malfunction in the movement system, e.g. of the pistons, the device automatically reverts to the operating configuration which provides for a fluid-tight coupling between the central member and the two heads, thus preventing leakage of the dryer gas and / or the possible entry of unwanted dust, moist ambient air or dirt into the dryer device.

[0070] According to a further embodiment, the movement system comprises at least one piston, and preferably two pistons, of the double-stroke pneumatic or electric type, each configured to reversibly move the first and / or second head between the operating configuration and the rotational configuration.

[0071] In this way, an alternative technical solution can be provided that allows the displacements of the first and / or second head to be effectively controlled with a single type of actuator.

[0072] Preferably, there are two pistons positioned diametrically opposite the central member.

[0073] In this way, it is possible to achieve a balanced and uniform movement of the first and / or second head with respect to the central member.

[0074] According to further embodiments, there are more than two pistons, e.g. four, preferably equidistant from each other and equidistant from the longitudinal axis.

[0075] According to some embodiments, the dryer device comprises a support frame for the central member and / or the first or second head.In some embodiments, the movement system comprises a magnetic actuator configured to move the first and / or second head with respect to the central member from the operating configuration to the rotational configuration.

[0076] In an example embodiment, the magnetic actuator may comprise a first plurality of magnets, e.g. permanent magnets, housed on the first head, and a first plurality of electromagnets, housed on the frame and facing the first plurality of magnets on the opposite side with respect to the central member, whereby the first plurality of electromagnets is selectively actuated in attraction so as to draw the first head towards itself and away from the central member in order to achieve the rotational configuration.

[0077] In addition or alternatively, the magnetic actuator may comprise a second pair of magnets, e.g. permanent magnets, housed on the second head and a second pair of electromagnets housed on the frame and facing the second plurality of magnets on the opposite side with respect to the central member, whereby the second plurality of electromagnets is selectively actuated in attraction so as to draw the second head towards itself and away from the central member in order to achieve the rotational configuration.

[0078] Of course, the position of the magnets and electromagnets can be modified, and in an appropriate manner, e.g. the magnets and electromagnets can only be positioned on the central member and heads.

[0079] Also in the case of the magnetic actuator, it is possible to provide a first and / or second elastic element configured to push the first or second head respectively into the operating configuration when the first pair of electromagnets or the second pair of electromagnets is deactivated.

[0080] This makes the technical solution easy to implement and also results in a very small footprint.In some embodiments, the first and / or second rotational actuation distance is comprised between 0.1 mm and 10 mm.

[0081] In some embodiments, when the first and / or second head are moved into the rotational configuration, the first seal is in contact with the first head and the central member and the second seal is in contact with the second head and the central member.

[0082] In this way, the first and second seals still remain in contact with both the central member and the respective first and second heads, thus still maintaining a certain tightness in the coupling. However, seal wear is reduced because the pressure to which the seals are subjected during rotation between the central member and heads is much lower than in the operating condition.

[0083] In other embodiments, when the first and / or second head are moved into the rotational configuration, either the first seal is spaced apart from the first head or the central member, or the second seal is spaced apart from the second head or the central member, so as to define an uncoupling configuration between the first or second head and the central member.

[0084] In this way, the first and / or second seal is detached from the central member or from the first and / or second head, effectively negating the wear of the seal due to the rubbing caused by the relative rotation between the central member or first and / or second head.

[0085] In this case, since the tightness between the central member and the first and / or second head is not guaranteed, it is advantageous that the gas flows through the dryer device are reduced or blocked, e.g. by providing special valve systems or by acting on the gas movement systems, e.g. by reducing the speed of the blowers.

[0086] In some embodiments, both seals are spaced apart from the central member or the respective heads.In some embodiments, the first and / or second head are spaced apart from the central member by more than 40 mm, preferably between 50 and 150 mm.

[0087] This makes the cartridge replacement operation particularly easy, thanks to the manoeuvring space left between the central member and heads, which allows easy access to the cartridges.

[0088] Preferably, during this step, the external connections of the dryer are intercepted as much as possible, e.g. by switching off any blowers and closing any valves.

[0089] In some embodiments, the drive system comprises a drive shaft, preferably extending along the longitudinal axis of the central member and rotating about it.

[0090] Preferably, the central member is rotationally secured to the drive shaft.

[0091] Preferably, the drive shaft is accommodated in the first and second heads with the option of free rotation and with the option of limited translation with respect to the first and / or second heads.

[0092] In this way, the drive shaft is adequately supported in rotation on the first and second heads to drive the central member in rotation with respect to the heads and, at the same time, does not prevent displacement of the first and / or second heads between the operating configuration and the rotational configuration.

[0093] According to a further embodiment, the drive system comprises a cam system and integrated sensor or proximity sensors positioned on the first and / or second head and markers comprised in the central member, or an encoder operatively connected to the motor device so that the desired step rotation of the central member can be performed precisely and efficiently.

[0094] Preferably, the first and second heads comprise a first cooling gas pipe and a second cooling gas pipe, respectively, the first and second cooling gas pipes being comprised in a cooling circuit to cool at least a third cartridge of the plurality of cartridges.

[0095] Thanks to this technical solution, it is possible to subject a cartridge to a cooling treatment that is particularly advantageous when implemented after the regenerationprocess, which generally requires treating a specific cartridge at temperatures comprised between 250°C and 300°C. Such cooling reduces the waiting time for the regenerated cartridge to be in the ideal condition to work at maximum efficiency as a gas dryer element.

[0096] In some embodiments, the plurality of seats comprises at least four seats for housing at least four respective cartridges.

[0097] This makes it possible to always have one or more cartridges affected by the process circuit, at least one affected by the regeneration circuit, and at least one affected by the cooling circuit.

[0098] Preferably, the seats are made equidistant from each other and arranged along an arc of a circle having its centre on the axis of rotation so as to position the cartridges at the relevant process, regeneration and cooling circuits.

[0099] This makes it possible to provide a dryer device that rotates at uniform and constant angle steps, efficiently and reproducibly moving the cartridges to the desired treatment steps (i.e. processing, regeneration, cooling).

[0100] Preferably, the number of seats and the respective cartridges is comprised between 3 and 10, more preferably between 3 and 6.

[0101] The greater the number of cartridges, the greater the constancy of gas drying and the greater the size and cost of the dryer device.

[0102] In an embodiment, the number of seats and respective cartridges is four.

[0103] In this case, preferably, the process circuit is fluid-dynamically connected to the first and at least the fourth seat to use the first and at least the fourth cartridge to dry the gas, the regeneration circuit is fluid-dynamically connected to the second seat to regenerate the second cartridge, and the cooling circuit is fluid-dynamically connected to the third seat to cool the third cartridge.

[0104] This means there are two cartridges involved in the process circuit at the same time, which reduces differences in the performance of the cartridges and provides a moreconstant drying process over time. At the same time, one cartridge is affected by the regeneration process and one is cooled to the desired temperature.

[0105] It can be seen that this technical solution also makes it possible to manage and optimise the timing of the regeneration and cooling process, thereby increasing the stability of the operating parameters of the overall drying process.

[0106] According to another embodiment, the central member comprises more than four cartridge seats, e.g. six, in which the first three (ordered in this case according to the direction of rotation of the central member) are affected by the process circuit, the fourth and fifth by the regeneration circuit and the sixth by the cooling circuit.

[0107] This further increases the consistency of the drying process over time.

[0108] In some embodiments, the central member comprises at least one locking device configured to selectively secure the plurality of removable cartridges to the central member.

[0109] This allows the desired cartridges to be quickly unlocked and replaced when the movement system is in the rotational configuration, more preferably when it is in the uncoupling configuration.

[0110] Preferably, the at least one locking device comprises quick-hook and quick-release devices each acting on a respective cartridge.

[0111] This allows the desired cartridge replacement to be carried out quickly and selectively. Preferably, during cartridge replacement, the dryer is isolated from the rest of the process, e.g. by switching off any blowers and closing any valves.

[0112] Thanks to this solution, it is possible to reduce the possible entry of dirt or dust into the central member when the movement system is in the rotational configuration. In some embodiments, the material dehumidification apparatus (or dryer device) comprises a first blower configured to move the gas in the process circuit and cooling circuit and fluid-dynamically connected to the first, fourth (if present) and third seats.In some embodiments, the material dehumidification apparatus (or dryer device) comprises a second blower comprised in the regeneration circuit that is fluid-dynamically connected by suction to the second seat.

[0113] Preferably, the cooling circuit downstream of the third seat is fluid-dynamically connected to the regeneration circuit upstream of the second seat.

[0114] In this way, the cooling gas leaving the third seat can be used, in whole or in part, to regenerate the second cartridge in the second seat.

[0115] This is advantageous because the gas leaving the third seat can have high temperatures, reducing the energy input required to bring it to the temperature required for regeneration of the desiccant material.

[0116] For this purpose, the regeneration circuit comprises, upstream of the second seat, a heater element configured to heat the gas to regeneration temperature.

[0117] Preferably, the cooling circuit downstream of the third seat and upstream of the second seat is fluid-dynamically connected to the process circuit.

[0118] In this way, a more or less large fraction of the cooling gas exiting the third seat can be introduced into the process circuit to dehumidify the material in the hopper.

[0119] The fraction of outgoing cooling gas from the third seat initiated in the regeneration circuit, and, by difference, that initiated in the process circuit, is preferably regulated by varying the speed of the second blower, or by means of a suitable throttling valve, which allows the desired gas flows to be obtained.

[0120] In particular, the Applicant observed that in the initial part of the cooling step the gas exiting the third seat is very hot but not dried, so that it is preferable to use it for a prevailing fraction in the regeneration circuit, in order to save energy for its heating and not to send insufficiently dry gas into the process circuit, while in the final part of the cooling step the gas exiting the third seat is much less hot and sufficiently dry, so that it can be used prevalently in the process circuit and, in part, to complete the regeneration of the second cartridge.In some embodiments, the step of activating the movement system by moving at least one of the first and second heads from the operating configuration to the rotational configuration, the step of rotating the central member by means of the drive system while the first and / or second heads are in the rotational configuration by bringing the first cartridge in place of the second cartridge, and the step of activating the movement system by restoring the operating configuration, are performed within a time of 10 seconds, preferably 5 seconds.

[0121] In this way, the changeover between the process cartridges and the already regenerated one is quickly performed, avoiding (or at least limiting) the possible entry of non-dehumidified air and dirt into the central member, while at the same time increasing the overall efficiency of the drying process.

[0122] Brief description of the drawings

[0123] The characteristics and advantages of the present invention will become clearer from the detailed description of a preferred embodiment thereof illustrated, by way of nonlimiting example, with reference to the appended drawings wherein:

[0124] - Figure la is a top view of a multi-tower cartridge dryer device made in accordance with the present invention,

[0125] - Figure lb represents a cross-sectional view of the device in Figure la,

[0126] - Figures 2a and 2b are another two views in axial section of the device in Figure la in which it is shown in an operating configuration and in a rotational configuration, respectively,

[0127] - Figures 3a, 4a, 5a are top views of different cross-sections of a central member of the dryer device in Figure la,

[0128] - Figures 3b, 4b, 5b are respective views of different axial sections of Figures 3a, 4a, 5a,

[0129] - Figures 6 and 7 are further axial sectional views of the device in Figure la in a rotational and operating configuration, respectively,- Figure 8 is a schematic view of an example of a material dehumidification apparatus made according to the present invention and its process, regeneration and cooling circuits,

[0130] - Figure 9 is a top view of a detail of a central member of a dryer device variant made according to the present invention.

[0131] Preferred embodiment of the invention

[0132] Referring to the schematic representation in Figure 8, 100 denotes a material dehumidification apparatus, comprising a hopper 2 containing a material to be dried 3, e.g. in the form of granules, as well as a process circuit CP comprising a multi-tower cartridge gas dryer device 1 configured to dry a gas to be introduced into the hopper 2.

[0133] In the example described herein, the material to be dried 3 consists of polymer granules, but the dryer device can obviously be used in dehumidification plants for different materials.

[0134] The apparatus 100 further comprises a regeneration circuit CG, a cooling circuit CRA, a first blower 70 fluid-dynamically comprised and operating in the process circuit CP and the cooling circuit CRA, and a second blower 71 fluid-dynamically comprised and operating in the regeneration circuit CG.

[0135] The process circuit CP is configured so that the process gas, i.e., the gas inserted into the hopper 2 for the purpose of drying the material 3 contained therein, is preferably air and can be selectively drawn from the environment or recirculated into the apparatus 100 by drawing it from an outlet pipe of the hopper 2. In addition, a locking valve 5 is interposed between the dryer device 1 and the hopper 2, adapted to fluid-dynamically isolate the hopper 2 from the dryer device 1 when desired, and a heating device (not shown) adapted to heat the gas to be inserted into the hopper 2 to a desired temperature.

[0136] Similar to what has been described for the process circuit CP, air is also selectivelypassed through the cooling circuit CRA by means of the first blower 70.

[0137] In the preferred embodiment shown in Figure 8, the cooling circuit CRA is also connected to the regeneration circuit CG which comprises a second blower 71 so that by changing the number of rotations per minute of the second blower 71, it is possible to determine the fraction of air from the cooling circuit CRA entering the process circuit CP and that entering the regeneration circuit CG.

[0138] In non-illustrated variants, typically for smaller devices, a regulating valve may be provided instead of the second blower 71.

[0139] The regeneration circuit CG comprises a heating element 4 configured to heat the air passing through it to a predetermined regeneration temperature.

[0140] In a preliminary general description, the dryer device 1 comprises a central member 10, extending along a longitudinal axis Z and interposed between a first head 20 and a second axially opposite head 30, a drive system 50 configured to rotate the central member 10 with respect to the two heads 20, 30 and a movement system 40 adapted to move the two heads 20, 30 in different operating configurations with respect to the central member 10. These components of the dryer device 1 will be described in more detail below for a more detailed description of the invention in question.

[0141] Figure la shows a top view of the dryer device 1, while Figures lb, 2a and 2b show some views of the dryer device 1 in different axial section planes.

[0142] A plurality of seats 11a, lib, 11c, lid configured to accommodate a respective plurality of removable cartridges 12a, 12b, 12c, 12d, and each comprising a desiccant material adapted to dry the gas passing therein, are obtained in the central member 10.

[0143] The four seats 11a, lib, 11c, lid obtained in the central member 10 have a substantially cylindrical extension and are defined by an alternation of radially projecting and recessing portions of the central member 10 in a tetra-lobed type shape.The seats 11a, lib, 11c, lid are obtained in the central member 10 so that they are equidistant from each other and equidistant from the longitudinal axis Z.

[0144] Advantageously, the central member 10 has a central portion recessed with respect to the maximum radial extensions of its axial ends.

[0145] As shown in Figure 4a, the central member 10 comprises locking devices 65 configured to make a quick-release hook individually on each of the four cartridges 12a, 12b, 12c, 12d. The locking devices 65 are preferably shaped like an arc of a circle and are articulated at the axial ends of the central member 10 to retain, and selectively release, the cartridges 12a, 12b, 12c, 12d in the respective seats 11a, lib, 11c, lid.

[0146] The cartridges 12a, 12b, 12c, 12d are generally cylindrical containers filled with desiccant material adapted to remove moisture from the passing gas. Preferably, such desiccant material is formed by molecular sieves.

[0147] In the embodiment described in Figures 1 to 8, the dryer device 1 comprises four seats 11a, lib, 11c, lid for four corresponding removable cartridges 12a, 12b, 12c, 12d.

[0148] In an alternative form shown in Figure 9, the central member 10 comprises six seats for as many cartridges.

[0149] As mentioned above, the first head 20 and the second head 30 are positioned at the axially opposite ends of the central member 10.

[0150] The first head 20 comprises a first plurality of pipes 20a pertaining to the process circuit CP, configured to pass the gas to be dried through the first cartridge 12a and, in parallel, through the fourth cartridge 12d, and to the regeneration circuit CG configured to regenerate a second cartridge 12b. More precisely, the first plurality of pipes 20a comprises a first process pipe 21 and a first regeneration pipe 22.

[0151] Similarly, the second head 30 comprises a second plurality of pipes 30a pertaining to the process circuit CP and the regeneration circuit CG. Again, the second plurality ofpipes 30a comprises a second process pipe 31 and a second regeneration pipe 32. It is interesting to note, as shown in Figure 8, that the process circuit CP comprises the first process pipe 21, the first seat 11a for the first cartridge 12a, the fourth seat lid for the fourth cartridge 12d (in parallel with the first seat 11a), and the second process pipe 31.

[0152] Similar considerations apply to the regeneration circuit CG comprising the first regeneration pipe 22, the second regeneration pipe lib for the second cartridge 12b and the second regeneration pipe 32.

[0153] A first seal 61 is provided to create a fluid-tight coupling between the central member 10 and the first head 20, while a second seal 62 is provided to create a fluid-tight coupling between the second head 30 and the central member 10.

[0154] The seals 61 and 62 are accommodated in respective seats on the axially opposite flanges of the central member 10.

[0155] The movement system 40 is configured to move the first and second heads 20, 30 along the longitudinal axis Z with respect to the central member 10 between:

[0156] - an operating configuration CO (shown for example in Figure lb, Figure 2a and Figure 7), in which the first and second heads 20, 30 are fluid-tightly coupled with the central member 10 and placed respectively at a first and second minimum distance Dml, Dm2 from it, and

[0157] - a rotational configuration CR. (shown for example in Figure 2b, Figure 5b and Figure 6) in which the first and second heads 20, 30 are displaced from the central member 10 to a first rotational actuation distance Dal and a second rotational actuation distance Da2 respectively, which is greater than the first and second minimum distances Dml, Dm2.

[0158] In the figures, the first and second minimum distances Dml, Dm2 are shown as nonzero, but it is also possible that they may be, independently of each other, zero.

[0159] As can be clearly seen from the above figures, in which the distances between thecentral member 10 and the heads 20, 30 are deliberately exaggerated for the sake of clarity, the first and second rotational actuation distances Dal, Da2 are such that, in the rotational configuration, the seals 61 and 62 housed in the central member 10 are completely detached from the first and second heads 20, 30 so that the rotation of the central member 10 with respect to the first and second heads 20, 30 can take place without causing any wear in the seals 61, 62. In this case, the rotational configuration defines an uncoupling configuration CDI.

[0160] In an embodiment, it is provided that, in the rotational configuration CR, the first or second rotational actuation distance Dal, Da2 is such that the first and second seals 61, 62, remain in contact with the first and second heads 20, 30. This makes it possible to maintain, during rotation of the central member 10, a continuity of coupling with the first and second heads 20, 30 with very limited wear of the seals 61, 62.

[0161] It should be noted that the minimum distances Dml, Dm2 from the central member 10 may differ from each other, e.g. due to different size or wear of the interposed seals 61 and 62, just as the rotational actuation distances Dal, Da2 may differ from each other.

[0162] In preferred embodiments, the various connected pipes included in the first and second plurality of pipes 20a, 20b are made in such a way as to allow for the desired movements of the first and second heads 20, 30 (e.g., the end parts of such pipes are foldable so as to follow the different configurations of the movement system 40, or are splined with granted axial sealing, etc.).

[0163] In more detail and with reference to the embodiment shown in Figure 6, the movement system 40 comprises a pneumatic actuator 41. The actuator 41 comprises two single-stroke pneumatic pistons 41a, 41b configured to move the first and second heads 20, 30 from the operating configuration CO to the rotational configuration CR. According to an embodiment, the first head 20 is secured to the bodies of the twopistons 41a, 41b while the second head 30 is secured to the rods 42a, 42b of the two pistons.

[0164] In addition, there is a first and second elastic element 45, 46 configured respectively to return the first and second heads 20, 30 to the operating configuration CO when the two pistons 41a, 41b are deactivated.

[0165] The first and second elastic elements 45, 46 are metal helical springs or similar technical solutions interposed between a support frame 47 and the first head 20 and, respectively, the second head 30 which push the first and second heads 20, 30 towards the fluid-tight coupling with the central member 10, i.e. towards the operating configuration CO.

[0166] According to a different embodiment (not shown in the figures), the two pneumatic pistons 41a, 41b are double-stroke, in which case the spring elements 45, 46 are not required to return to the operating configuration CO.

[0167] According to a further embodiment (not shown in the figures), the movement system comprises a magnetic actuator comprising a first pair of permanent magnets housed on the first head 20 and a first pair of selectively attractively actuated electromagnets housed on the frame of the dryer device so as to face the first pair of permanent magnets and create the rotational configuration CR when activated.

[0168] Preferably, the magnetic actuator comprises a second pair of permanent magnets housed on the second head 30 and a second pair of electromagnets selectively actuated in attraction housed on the frame so as to face the second pair of permanent magnets and create the rotational configuration CR. when activated.

[0169] Also in this embodiment, the magnetic actuator comprises the two elastic elements 45, 46 each constrained to the frame 47 and respectively to the first and second heads 20, to push the first or second head 20, 30 respectively in the operating configuration CO when the first pair of electromagnets and / or the second pair of electromagnets is deactivated.The drive system 50 is associated with the central member 10 and is configured to rotate the central member 10 in steps about the longitudinal axis Z when the first and / or second heads 20, 30 are moved into the rotational configuration CR.

[0170] The drive system 50 comprises a drive shaft 51 extending along the longitudinal axis Z and rotating about it as shown in Figure 1 by the curved arrow.

[0171] In alternative forms not shown in the figures, the drive system 50 comprises gear wheels or belts configured to rotate the central member 10.

[0172] It can be seen from Figure 6 that the drive shaft 51 advantageously passes through the axial bore of the helical springs 45, 46 and is solidly secured to the central member 10 so as to effectively transfer the desired rotational motion.

[0173] The first and second heads 20, 30 comprise a first and second bore 25, 35 respectively, configured to pass the drive shaft 51 through them with granted rotation and, at the same time, allow the desired displacements of the first and / or second heads 20, 30 between the operating configuration CO and the rotational configuration CR (also visible in Figure lb).

[0174] The drive system 50 only performs a discontinuous rotation of the central member 10 when the heads 20, 30 are moved to the rotational configuration CR. The amplitude of rotation depends on the number of seats provided in the central member, and in the preferred example described here is approximately 90°.

[0175] The step rotation is controlled by predetermined programming via an encoder in the drive system 50.

[0176] Alternatively, the drive system 50 can perform step rotation by means of an integrated cam and sensor system, or proximity sensors positioned on the first and / or second head 20, 30 and respective markers comprised in the central member 10 can be used.

[0177] For the sake of completeness, some preferred modes of operation of this invention are described below.Initially, a material dehumidification apparatus 100 is provided comprising the desiccant device 1 in which four cartridges 12a, 12b, 12c, 12d are removably housed in the respective seats 11a, lib, 11c, lid.

[0178] The dryer device 1 is in the operating configuration CO shown in Figure lb, in which the first and second heads 20, 30 are at a first and second minimum distance Dml, Dm2 from the central member of 0 to 3 mm, for example, in order to achieve a fluid-tight coupling.

[0179] As can be seen from the diagram in Figure 8 and Figure 3a, in the initial configuration the first seat 11a and the fourth seat lid are affected by the process circuit CP, the second seat lib is affected by the regeneration circuit CG and the third seat 11c is affected by the cooling circuit CRA.

[0180] The first blower 70 of the apparatus 1 shown in Figure 8 can selectively suck in gas (air) from the surrounding environment or from the outlet of the hopper 2 (thus downstream of the dehumidification process that takes place in the hopper itself). In the second case, the recalled air typically has a temperature comprised between 60° and 80° and a high moisture content.

[0181] This moist air is pushed by the first blower 70 through the molecular sieves of the first cartridge 12a and the fourth cartridge 12d, which are affected by the process circuit CP. The dry air leaving the first cartridge 12a and the fourth cartridge 12d has a very low dew point, between -10°C and -50°C, and after appropriate heating is introduced into the hopper 2 to continue the dehumidification process of the granular material 3 contained therein.

[0182] As can be seen from Figure 8, part of the air leaving the first blower 70 is diverted into the cooling circuit CRA to cool the third cartridge 12c, at the outlet of which it can be either introduced into the regeneration circuit CG to regenerate the second cartridge 12b, or, in varying fractions, introduced back into the process circuit CP.The air which began in the regeneration circuit CG is guided through a heater 4, e.g. of the electric type, and heated to a temperature of approximately 250°C to 300°C. The air thus heated is sucked in by the second blower 71 and passed through the second cartridge 12b in order to remove (strip) the moisture present in the molecular sieves, thus restoring their improved hygroscopic capacity.

[0183] The third cartridge 12c present in the seat 11c is a cartridge that has just finished the regeneration process and therefore has a very high temperature. Since a cartridge that is too hot cannot adequately adsorb moisture from a gas, and thus has too low a hygroscopic yield, it is advantageous to bring it into the process circuit CP after it has been cooled by the process air from the first blower 70 (which can have a temperature between 60° and 80°C).

[0184] After a predetermined time, which may be between 30 minutes and 2 hours, or, if necessary, when the air in the process circuit exiting the dryer device 1 is not sufficiently dry, the cartridges 12a-12d are moved between the different circuits defined in the heads 20, 30.

[0185] In detail, this is done by moving the first and second heads 20, 30 from the operating configuration CO to the rotational configuration CR via the movement system 40 by extending the two pistons 41a, 41b.

[0186] In this configuration, the first and second heads 20, 30 are brought to a respective rotational actuation distance Dal, Da2 greater than the first or second minimum distance Dml, Dm2 and between, for example, 1 and 10 mm, which, in the example described here, achieves a non-contact condition between the seals 61, 62, and the heads 20, 30.

[0187] At this point, while the first and second heads 20,30 are in the rotational configuration CR, the central member 10 is rotated 90° about the longitudinal axis Z by the drive system 50 in the direction indicated by the arrow in Figure la.In this way, the first cartridge 12a is brought in place of the second cartridge 12b, within the regeneration circuit CG, the second cartridge 12b is brought in place of the third cartridge 12c within the cooling circuit CRA, the third cartridge 12c is brought in place of the fourth cartridge 12d within the process circuit CP, and the fourth cartridge 12d is brought in place of the first cartridge 12a remaining within the process circuit CP.

[0188] At this point the movement system 40 is activated again, restoring the operating configuration CO with the new arrangement of the plurality of cartridges. As described above, this can be advantageously achieved, for example, by deactivating the two pistons 41a, 41b and letting the two springs 45, 46 bring the two heads 20, 30 back into fluid-tight coupling with the central member 10.

[0189] During the rotational configuration CR, which is maintained for a very short time, preferably between 2 and 10 seconds, more preferably around 5 seconds, the first blower 70 and the second blower 71 are either brought to low speed or switched off. Alternatively or additionally, the dryer device 1 is to be isolated from the process circuit by means of valve systems.

[0190] The method envisages that at this point the regeneration process is carried out for the first cartridge 12a while the other cartridges are affected by the process circuit CP and cooling circuit CRA until the subsequent rotation step of the central member 10 which will be carried out in the same manner as above.

[0191] When it is necessary to replace one or more cartridges, the two heads 20, 30 are moved to the decoupling configuration CDI described above and the cartridges to be replaced are easily removed from the respective housings after releasing the respective locking device 65. After inserting the new cartridges into the respective seats, the respective locking device 65 is re-engaged and the heads 20, 30 returned to the operating configuration CO.Naturally, those skilled in the art may make further modifications and variants to the above-described invention with the purpose of meeting specific and contingent application needs, variants and modifications in any case falling within the scope of protection as defined by the successive claims.

Claims

Claims1. A gas dryer device (1) of the multi-tower cartridge type comprising:• a central member (10) extending along a longitudinal axis (Z) and comprising a plurality of seats (11a, lib, 11c, lid) which are configured to receive a respective plurality of cartridges (12a, 12b, 12c, 12d), each one comprising a drying material which is suitable for drying said gas,• a first head (20) and a second head (30) which are positioned at the axially opposite ends of said central member,• the first head (20) comprising a first plurality of pipes (20a) of a process circuit (CP) configured to cause said gas to pass through a first cartridge (12a) of said plurality of cartridges (12a, 12b, 12c, 12d) in order to dry said gas, and a regeneration circuit (CG) which is configured to regenerate a second cartridge (12b) of said plurality of cartridges (12a, 12b, 12c, 12d),• the second head (30) comprising a second plurality of pipes (30a) of said process circuit (CP) and said regeneration circuit (CG),• a first seal (61) which is interposed between said first head (20) and said central member (10) and which is configured to bring about a fluid- tight coupling between said first head (20) and said central member (10),• a second seal (62) which is interposed between said second head (30) and said central member (10) and which is configured to bring about a fluid-tight coupling between said second head (30) and said central member (10),• a movement system (40) which is connected to said first and / or second head(s) (20, 30) and which is configured to move reversibly along saidlongitudinal axis (Z) at least one of said first or second heads (20, 30) betweeno an operating configuration (CO), in which said first and second heads (20, 30) are coupled in a fluid-tight manner to said central member (10) and are positioned at a first and second minimum distance (Dml, Dm2) from said central member (10), respectively, ando a rotational configuration (CR), in which at least one of said first or second heads (20, 30) is displaced from said central member (10) at a first or second rotational actuation distance (Dal, Da2) greater than said first or second minimum spacing (Dml, Dm2),• a drive system (50) which is secured to said central member (10) and which is configured to rotate said central member (10) in steps about said longitudinal axis (Z) when said first and / or second head(s) (20, 30) is / are moved into said rotational configuration (CR).

2. A device (1) according to the preceding claim, wherein said movement system (40) comprises at least one pneumatic, magnetic or electric actuator (41).

3. A device (1) according to the preceding claim, wherein said at least one pneumatic or electric actuator (41) comprises at least one single-stroke pneumatic or electric piston (41a, 41b) configured to move said first and / or second head (20, 30) from said operating configuration (CO) to said rotational configuration (CR).

4. A device (1) according to any one of the preceding claims, wherein said movement system (40) comprises a first elastic element (45) and / or a second elastic element (46) configured to move said first and / or second head (20, 30) into said operating configuration (CO), respectively.

5. A device (1) according to any one of the preceding claims, wherein, when said first and / or second head(s) (20, 30) is / are moved into said rotational configuration (CR):- said first seal (61) is in contact with said first head (20) and said central member (10) and- said second seal (62) is in contact with said second head (30) and said central member (10).

6. A device (1) according to any one of claims 1 to 4, wherein, when said first and / or second head(s) (20, 30) is / are moved into said rotational configuration (CR):- said first seal (61) is spaced apart from said first head (20) or from said central member (10) or- said second seal (62) is spaced apart from said second head (30) or from said central member (10),thereby defining an uncoupling configuration (CDI) between said first head or second head (20, 30) and said central member (10).

7. A device (1) according to any one of the preceding claims, wherein:• said drive system (50) comprises a drive shaft (51) extending along said longitudinal axis (Z) and rotating about said longitudinal axis (Z),• said drive shaft (51) is rotationally secured to said central member (10), • said drive shaft (51) is received in said first and second heads (20, 30) with the capacity to freely rotate with respect to said first and second heads (20, 30) and with the capacity for limited translational movement with respect to said first and / or second head(s) (20, 30) in order to allow the movements of said first and / or second head(s) (20, 30) between said operating configuration (CO) and said rotational configuration (CR).

8. A device (1) according to any one of the preceding claims, wherein said first and second heads (20, 30) comprise a first cooling gas pipe (23) and a second cooling gas pipe (33), respectively, said first and second cooling gas pipes (23, 33) being comprised in a cooling circuit (CRA) in order to cool at least a third cartridge (12c) of said plurality of cartridges (12a, 12b, 12c, 12d).

9. A device (1) according to claim 8, wherein said plurality of seats comprises at least four seats (11a, lib, 11c, lid) for receiving respective cartridges (12a, 12b, 12c, 12d) and wherein:- said process circuit (CP) is fluid-dynamically connected to said first and fourth seats (11a, lid) so as to use said first cartridge (12a) and at least a fourth cartridge (12a, 12d) for drying said gas,- said regeneration circuit (CG) is fluid-dynamically connected to said second seat (lib) for regenerating said second cartridge (12b) and- said cooling circuit (CRA) is fluid-dynamically connected to said third seat (11c) for cooling said third cartridge (12c).

10. An apparatus (100) for dehumidifying materials, comprising:• a hopper (2) containing a material (3) to be dehumidified,• a process circuit (CP) connected to said hopper in order to introduce a dry gas into said hopper and comprising a dryer device (1) configured to dry the gas to be introduced into said hopper in order to dehumidify said material,wherein said dryer device (1) is made according to any one of the preceding claims.

11. An apparatus (100) according to the preceding claim, wherein said dryer device (1) is made according to any one of claims 8 to 9 and comprises:• a first blower (70) fluid-dynamically connected to said first and third seats (11a, 11c) in order to move gas in said process circuit (CP) and in said cooling circuit (CRA) and• a second blower (71) fluid-dynamically connected in terms of intake to said second seat (lib) and / or a flow control valve comprised in said regeneration circuit (CG),wherein said cooling circuit (CRA) is fluid-dynamically connected downstream of said third seat (11c) and upstream of said second seat (lib) to said process circuit (CP) and said regeneration circuit (CG).

12. A method for regenerating a cartridge of a gas dryer device (1) of the multitower cartridge type, comprising:providing a dryer device (1) made according to any one of claims 1 to 9, activating said movement system (40) by moving at least one of said first and second heads (20, 30) from said operating configuration (CO) to said rotational configuration (CR),rotating said central member (10) by means of said drive system (50) while said first and / or second head(s) (20,30) is / are in said rotational configuration (CR) by bringing said first cartridge (12a) in place of said second cartridge (12b),activating said movement system (40) by restoring said operating configuration (CO),activating a regeneration process for said first cartridge (12a).

13. A method for replacing a cartridge in a gas dryer device (1) of the multi-tower cartridge type, comprising:Providing a dryer device (1) made according to any one of claims 6 to 9,Activating said movement system (40) by moving at least one of said first and second heads (20, 30) from said operating configuration (CO) to said uncoupling configuration (CDI),Replacing said cartridge in the respective seat and- Activating said movement system (40) by restoring said operating configuration (CO).

14. A method for replacing a cartridge according to the preceding claim, wherein, in said uncoupling configuration (CDI), said first and second heads (20, 30) are spaced apart from said central member (10) by more than 40 mm.

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