GB2425164A

GB2425164A - Modular continuous evaporator drier apparatus with separate microwave heating and air flow chambers

Info

Publication number: GB2425164A
Application number: GB0604950A
Authority: GB
Inventors: Amedeo Pagotto
Original assignee: S M C Srl
Current assignee: S M C Srl
Priority date: 2005-03-14
Filing date: 2006-03-13
Publication date: 2006-10-18
Anticipated expiration: 2026-03-13
Also published as: DE102006009258A1; FR2883068A1; ITTV20050039A1; DE102006009258B4; GB0604950D0; FR2883068B1; GB2425164B

Abstract

A modular continuous fluidised evaporator drier apparatus A for processing loose or granular material (M, Figure 2) comprises: main chamber S having microwave heating devices 3, and respective material intakes and outlets 102, 103; fluidised support transportation bed 2; and at least one secondary chamber 4 extending below main chamber S at a controlled atmosphere, with forced airflow, and communicating mono-directionally with upper chamber S. An aspiration unit controls the chamber atmosphere pressure, and logic sensor controls regulate system ventilation, temperature and pressure. Fluidised bed 2 may be a looped conveyor belt that is air permeable one way, i.e. from the bottom upward only; bed 2 may reflect incident microwaves back through material M. Plural devices A may be arranged in an overlapping cascade (Figure 4). As shown in Figure 3, conveyor A may be arranged above a further conveyor B, without microwave dryers, arranged to lower accumulated material energy.

Description

MODULAR APPARATUS, WITH A CONTINUOUS FLUIDIZED EVAPORATOR-DRIER FUNCTION, FOR THE PROCESSING OF LOOSE OR GRANULARMATERIAL AND NON-CONTINUOUS MODULAR PLANT OBTAINED IN SUCH A

WAY

FIELD OF THE INVENTION This invention has mainly as its object a modular apparatus with a continuous fluidized evaporator-drier function, for the processing of loose or granular material, as well as a related plant obtained by means of the use of at least one modular apparatus. The invention finds particular though not exclusive application in the field of the processing of granular or loose materials, conventionally known as materials regarding which there is the need to check for the humidity percentage present in them. In principle, it can be observed that many materials once obtained, be they natural, crude or even semi-finished, like for example granular plastic for moulding apparatus of plastic products, or foodstuffs such as grains or medicine, can have higher or lower humidity percentages, which are undesirable for subsequent processes like, for example, packaging. In order to allow the use of said materials that are not processed in the productive chains, and in particular with the aim of improving the output and the quality of the finished product, the more or less significant reduction of the humidity percentage noticed at the beginning is often necessary. It is the case, for example, of grains such as wheat, which, if stored in large containers even if temporarily or packaged for long periods without processing, with a humidity percentage which is not controlled, would otherwise give rise to fermentation.It is also the case of plastic granules necessary to feed moulding plants, regarding which, obviously, the more the humidity percentage of the packaging deviates from that required by the moulding lines, the more it will be necessary to perform further in house processing, with consequent time and financial expenditures, to reach the desired levels. It was therefore a priority to hypothesize processes and apparatus that could have as a main aim the control if not a total elimination of the humidity percentage. These processes and the relative apparatus, progressively developed in time, substantially, have been using devices able to obtain the evaporation of water, an aim reached by the use of thermic energy or with the aid of arid gases. In other words, inside a container, loaded with material beforehand, the material itself, on the basis of certain working cycles, is subjected to one or another form of water removal, but also by both, until progressively reducing its presence. In some cases, there are containers for processing, where the material is substantially static, in others the same material is dynamic, sometimes even fluidized, following a determined path, divided into more processing stages.

PRIOR ART In literature, different patent-rights are known which have intended to solve more or less effectively the problem of humidity control. For example, US3574951 (Oetjen) describes an apparatus composed of two units, respectively a first like a hopper where the material in frozen particles is introduced which by falling are accumulated on a vibrating table. A second unit, adjacent to said first, receives the frozen particles from the vibrating table. Said second unit consists of a vertical cylindrical container, coaxially to which a rotation shaft is provided and around it a helical bed on one side of which at the beginning of the helicoid, it receives the frozen particles from the vibrating table. Inside said second unit a vacuum and heating means are provided. EP1108967 (Marcheschi) provides a vertical drier composed of a chamber in which the vacuum originates, and a series of vibrating trays one above the other and parallel to each other on which the granular material to be dried is laid which, in descent, follows a path from the top downwards. The chamber is of the type heated by induction providing peripherally an airspace inside which the heated fluid circulates. US2419875 (Birdseye) describes a container for the extremely fast drying of food. On the inside of this container, more intercommunicating chambers aligned vertically are provided, where for each chamber a corresponding horizontal conveyor belt is housed and above this, on the ceiling, a relative heat radiating means directed towards the underlying conveyor belt. The product fed from above by gravity is laid on the first conveyor belt, which from the other side, once performed its travel, will make the material fall into the underlying area through an opening introduced on the conveyor belt of the underlying chamber and so on. The final stages do not provide radiating heat means. Finally the participation of a hot dehydrating arid gas is provided. To the list mentioned above, many other less significant patents can be added, however, among which we cite the following for completeness of information. DE2246027 (Puschner) refers to a conventional drier with more conveyer belts, distributed in separate chambers, inside which a fluid circulates to bring the environment to temperature. In US5189809 (Bailey), vibrating panels are provided that receive the material to be processed, whose lower panel is subjected to the action of infrared rays. US3742614 (Bettermann). It is a device for the thermic processing of powdered or granular material, that includes a container with a plurality of circular cradles mounted one above the other in said container for the successive transfer of the material from the top downwards, a system of selective control of the temperature of the cradles, and a vibration device of the vibrating cradles to move the material towards the following stages with pre-selected depth of layers. There are then solutions that, for some parts of their content, have been held, by the applicant, more important than the previous ones.

PRIOR ART CLOSER TO THE INVENTION DE4036112 (Heindl), describes a horizontal cylindrical container for drying along which two conveyer belts are positioned in which one is partly overlapping the other. The material is introduced through an upstream opening and therefore started downwards. At least in one corresponding zone, where the material is heated by microwaves, the gas is passed from the top downwards or vice versa. The material to be processed is in granular or fibre form. US3063848 (Van Gelder) consists of an apparatus for processing by means of a dehydration process of food such as garlic, onions, potatoes and similar. The apparatus, in substance, provides the use of more vibrating tables, divided into two opposite groups, with overlapping inclined planes alternated in such a way that the lower extremities of each, are arranged at the top of the underlying inclined plane. A peripheral circuit provides to feed with hot air, an airspace provided along the vibrating table in the part underlying the plane which collects the material to be processed. The hot air can, in one case, be combined with dehydrating gases, and supported by single ventilating units, which all leads to the airspace underlying the table which collects the material to be processed.The air forced into the airspace of the vibrating table is conveyed upwards determining a floating effect of the material to be processed. In this case the support plane consists of a net woven in stainless steel wire with meshes of 20 x 200. Summarizing the information acquired in such a way, it is possible to say that the following are known: - Apparatus for the continuous processing of material with a vertically developed multistage path, commonly called "towers" and apparatus, still with a multistage path, but developed horizontally, commonly called "tunnels"; - Tunnel apparatus, that provide vibrating tables, one after the other along which the material to be processed flows; - Apparatus that, for the processing of the material, use hot airflow generators with convective motion; or apparatus with the circulation of arid gas, alternatively a hot airflow combined with arid gas; or apparatus with microwave devices alternatively combined with a hot airflow; - Apparatus that, for the processing of the material, provide in the main container the generation of a vacuum. Finally, in ITTV2003A000062 (Pagotto), a continuous multistage, fluidized, evaporator-drier apparatus is proposed, of the type with a main chamber at a controlled atmosphere, provided with microwave devices for the processing of loose or granular material, including: - a container for the continuous processing of material in a tunnel with a horizontally developed multistage path that provides in the main chamber, heated by the microwave devices, an underlying fluidized support bed for the material, said bed consisting of a vibrating table with height differences which receives the material to be processed upstream through a hopper to provide downstream a corresponding exit of the material processed in such a way;- to every stage of the path along the container, at least one secondary chamber corresponds, obtained in the part underlying the fluidized support bed of the material, whose secondary chamber is intercommunicating with an underlying base airspace, inside which circulates a forced airflow that cooperates with heating means; - a vacuum pump group to control the atmospheric pressure of the main chamber; - actuating elements with eccentric cam and support means of the fluidized bed to obtain the vibrating effect; - a logic control unit of the apparatus, which, by means of sensors, controls also individually the single functions and makes them interact amongst themselves, respectively the ventilation, temperature and atmospheric pressure.

DISADVANTAGES The apparatus described above, and in particular those remembered in the closest prior art, have some disadvantages. Fundamentally, one can state that the known solutions require significant sizes, above all with reference to the length. In ITTV2003A000062 (Pagotto), for instance, the translation plane consists of a so-called fluidized support bed of the material. This translation plane is described as a dynamic plane with a vibrating function for the advancement of the material, provided along the path with a series of height differences. The need to provide a kind of consequential steps requires a plane that is particularly developed in length and this on the basis of the different stages and the material processing path. This, from a practical point of view, requires sites especially adapted to receive plants of such a size, the latter circumstance is not always possible and very binding in any case.To this it can be added that the known plant, giving the translation plane a vibrating function, requires a series of mechanical and electromechanical elements and relative process plant engineering that therefore allow the execution of such function. The aspects indicated before contribute without a doubt to make the known plant even more imposing, heavy, therefore with greater problems in relation to its arrangement. It must moreover be added that said last function participates to make the plant complex, requiring maintenance and, from a financial viewpoint, with significant production times and costs. A second, but not therefore negligible negative aspect still with reference to the well-known plants, relates to the fact that the same are usually realised on commission, therefore with mutable and specific characteristics. Consequently, orders that are executed, not being able to consider standard units of the plant, as it were, since each plant has to perform the particular needs of the client company, are particularly complex, they require particular preparation and as known they are not compatible with the needs of an industrial company nervous about production quantity.This situation, involves noticeably difficulties linked to production and still more for the client subject, since in the moment in which the plant no longer satisfies their needs, it is not reasonable to suppose any intervention to change the same, for example with reference to the quantity of material to be processed. The essential aim of this invention is also to avoid the above-mentioned disadvantages.

BRIEF DESCRIPTION OF THE INVENTION This and other aims are reached with this invention according to the characteristics of the included claims, solving the problems mentioned by means of a modular apparatus with a continuous fluidized evaporator-drier function, for the processing of loose or granular material and a non-continuous modular plant obtained in such a way, in which at least one modular apparatus includes: - a main chamber at a controlled atmosphere, for the processing of loose or granular material, with a continuous linear tunnel, which provides, at the main chamber heated by microwave devices, an underlying fluidized support bed of the material, which receives upstream, by descent, the material to be processed to provide downstream a corresponding exit of the material processed in such a way;- along the main chamber at a controlled atmosphere, at least one secondary chamber intercommunicating with said first, the fluidized support bed of the material obtained in the underlying part, in which secondary chamber a forced airflow circulates that cooperates with heating means; - a possible vacuum pump group to control the atmospheric pressure of the main chamber; - a logic control unit of the apparatus, which, by means of sensors, controls also individually the single functions and makes them interact together, respectively the ventilation, temperature and atmospheric pressure; and furthermore in which a modular plant obtained in such a way provides at least one modular apparatus unit in line with a second apparatus for the subsequent cooling process of the material not provided with microwave devices.

AIMS In such a way, through the considerable creative contribution the effect of which constitutes immediate technical progress, some aims are achieved, achieving the optimization of the apparatus and the plant for a conditioning cycle of the material that includes the drying-evaporation phase of the humidity present. A first aim is to allow a significant containment of the sizes of the plant. And actually, the fact of being able to use modular apparatus allows a different and more rational arrangement of the same, in such a way as to contain, at least discreetly, the sizes. For example, in a preferred solution, if compared with ITTV2003A000062 (Pagotto), the allowing, at least partially, of the overlapping at equal cycle, results in a great reduction of the development in length. A second aim, still thanks to the provision of modular apparatus, has been that of greatly contributing to the reduction of the constructive complexity of the plant, without changing the capacities regarding the effectiveness of the conditioning cycle. In other words, if compared with ITTV2003A000062 (Pagotto), in the drying-evaporation apparatus the vibrating function of the translation plane has been eliminated. This from a practical point of view has allowed a considerable constructive simplification, completely avoiding the necessary mechanics and process plant engineering for the vibration function. To this it can be added that there has been also a further containment of the sizes, so as to benefit from shorter realization times and costs of the plant itself. A third aim, consists of the fact of being able to allow greater flexibility, both in the realizable phase of the plant, and also in the case in which the same must be modified to optimize different processing cycles, with the object of satisfying the most multiple needs. The possibility to implement the capacities of the plant itself, therefore varying the number of apparatus, with simple solutions, for example by means of an in line combination of a second apparatus, allows to carry out different conditioning cycles of the material, and as a consequence does not bind the user to the type of plant originally bought. From a production of the apparatus viewpoint, the advantages are clear for the company, provided that a more rational management of the components is allowed with a good functional and rational execution of the orders at low costs and in very short times. It goes without saying, that the conditioning cycle, can therefore be further optimized, making the obtainment of multiple results possible and adapting it in the best possible way to the characteristics of the material to be processed according to the needs of the user. These, but also other advantages or aims will appear from the following detailed description of some preferred embodiments with the aid of the enclosed schematic drawings, whose details of execution are not to be considered limitative but only illustrative.

CONTENT OF THE DRAWINGS Figure 1, is a side-view of a modular apparatus with an evaporator-drier function. Figure 2, is a sectional view on the cross-sectional plane of the apparatus of Figure 1. Figure 3, is a side-view of a single-stage plant that includes a modular apparatus, as in Figure 1, with an evaporator-drier function. Figure 4, is a side-view of a multistage plant that includes a series of modular apparatus, each as in Figure 1, having an evaporator-drier function. Finally, Figure 5, is a plan view of the plant shown in Figure 4.

PRACTICAL DESCRIPTION OF THE REALIZATION OF THE INVENTION With reference also to the Figures, it is observed that a modular apparatus A with a continuous evaporator-drier function, for the conditioning along a tunnel, of granular or loose material M, consists of a container 1, in this case, parallelepiped. Said container 1, in a first realizable hypothesis (Figure 1), is held up by underlying vertical posts, fixed to the floor, respectively front 100 and back 101, the latter are of greater height than the former. In this way, the container 1 acquires an inclined orientation, and in such a way as to present an intake entry 102 for intake from above of the material M to be processed, positioned in the top of the low part of the container 1 nearer to the floor, and an outlet 103, for the processed or partially processed material M, for outlet downwards of the material, positioned in the underside of the higher part of the container 1 with respect to the floor. Inside container 1, following a linear path in the main chamber S that develops longitudinally with respect to said container 1, the material M is processed, which is introduced upstream of the path along the apparatus A, or through the intake above entry 102. Inside the main chamber S, the atmospheric pressure is controlled, in one case, by an aspiration unit, for example a vacuum pump group, whose functioning is managed by the logic unit of the apparatus A and interacts with the other functions of the same. The material M that therefore passes through the intake above entry 102, is laid over and to one end of the fluidized bed 2, flat, extending along the container 1, directed longitudinally with respect to said container 1 and therefore to the main chamber S. In this case, it is observed that the fluidized bed 2 consists of a conveyor belt, of the looped type which is air permeable mono-directionally and in particular from the bottom upwards but not vice versa. Even more in particular, the fluidized bed 2 is obtained from a pre-coupled material, where the lower layer is obtained in Kevlar while the upper layer is silicon-based materials with micro holes.The fluidized bed 2, in an operative condition of the apparatus A, with the material M supported and transported by it, is therefore subjected to a microwave beam generated by microwave devices 3, for example magnetron, which are positioned along the container 1 and directed towards the underlying fluidized bed 2. The microwave beam generated in such a way through the mass of fluctuating material M, from the top downwards, hits said fluidized bed 2, without crossing it, to then be resent or reflected in the opposite direction and therefore to pass again through the mass of material M. At the opposite down streamside, the fluidized bed 2 leads to the outlet 103 to allow the passing of the material M to the subsequent working stages. In a preferred solution, at the main chamber S mixer devices 4 can be provided, of the transversal type, depending on the characteristics of the material M to be processed. It has been observed that above the fluidized bed 2, still in the main chamber S, microwave devices 3 are provided, engaged to and mounted on the top side of the container 1. Said microwave devices 3 are aligned in groups, by parallel rows and distributed for almost the whole length of the main chamber S in such a way to be directed perpendicularly towards the underlying fluidized bed 2. Below the fluidized bed 2 at least one secondary chamber or box 4 is provided with a bottom and walls. More particularly, inside the secondary chamber or box 4 a forced airflow at a controlled temperature flows, in this case laterally, which, coming from a heating circuit, is directed towards the top and moves, in one direction, across the overlying fluidized bed 2. In this way, the material M, during the whole path inside the main chamber S, hit by the airflow, is in a fluctuating condition. The air present in the main chamber S, which during the processing of the material M is therefore enriched with humidity, is therefore extracted by means of a special aspiration unit, and through a circuit, reused to be reintroduced into the convection cycle. In a first preferred solution, (see Figure 4) a non-continuous modular plant for the processing of loose or granular material M, provides the linear association, one behind the other and partially overlapping, of a series of modular apparatus A. More particularly, each modular apparatus A is partially overlapping with the highest part of the container 1, overlapping the lower part of the next apparatus A, downstream, in such a way as to make coincide the outlet 103 of the material M from one apparatus A with the intake 102 of the next apparatus A to which it is connected. In this case, it is observed that the passing of the material M from an apparatus A, to the following one is airtight and occurs by fall under gravity.Upstream of the plant represented in Figure 4, at least one humidity sensor is provided that cooperates with detecting means of the weight of the material M and the temperature, while downstream and at the end of the modular plant, an apparatus B is provided with the aim of lowering the energy accumulated by the material M, coming from the upstream cycle. In a second preferred solution of the plant for the processing of loose or granular material M, (see Figure 3), the association of a single modular apparatus A is provided, placed horizontally, with an apparatus B with the aim of lowering the energy accumulated by the material M. In this case, it is observed that the modular apparatus A is exactly overlying, parallel and spaced by means of posts 104, 105 with respect to the underlying apparatus B. In more detail, from the overlying modular apparatus A the material M by simply falling, passing through the outlet 103, is placed inside the apparatus B on a second fluidized bed 2.Essentially it can be stated that the apparatus B with the aim of lowering the energy accumulated by the material M processed upstream, is very similar to the modular apparatus A, differentiating itself by the fact of not providing microwave generator devices 3, for example magnetron, that are provided in the modular apparatus A instead.

Claims

1. Modular apparatus with a continuous fluidized evaporator-drier function, for the processing of loose or granular material characterized in that at least one modular apparatus A consists of: a main chamber S, for the processing of loose or granular material M, with a continuous tunnel following a linear path; microwave devices 3 arranged to heat the material in the main chamber S, an intake 102 arranged to receive upstream, by falling therethrough, the material M to be processed; an outlet downstream 103 for the processed material M; a fluidized support and transportation bed

2 for transporting the material M between the intake and the outlet, at least one secondary chamber 4 extending along the main chamber S at a controlled atmosphere, and communicating mono-directionally with said main chamber S underneath the fluidized support and transportation bed 2 of the material M, in which secondary chamber 4 a forced airflow at a controlled temperature is arranged to circulate; an aspiration unit in the main chamber S to control the atmospheric pressure of said main chamber S; a logic control unit of the apparatus A, which, by means of sensors, controls individually and in coordination the following functions: ventilation, temperature and atmospheric pressure. 2. Modular apparatus with a continuous fluidized evaporator-drier function, according to claim 1, characterised in that the fluidized bed 2 consists of a conveyor belt, which is of the looped type and is air permeable monodirectionally from the bottom upwards but not vice versa.

3. Modular apparatus with continuous evaporator-drier function, fluidized, according to claim 1 or claim 2, characterised in that the microwave generator devices 3 are provided, positioned along the chamber S and directed towards the underlying fluidized bed 2 present in the main chamber S, in such a way that the microwave beam generated crosses the mass of fluctuating material M, from the top downwards, hits said fluidized bed 2, to then be reflected back through the mass of material M.

4. Plant with a plurality of modular apparatus with an evaporator-drier function according to any previous claim, characterized in that a linear association is provided, one behind the other and partial overlapping, of the modular apparatus A, in which the highest part of each modular apparatus A is partially overlapping with the lowest part of the next apparatus A, downstream, in such a way to make the outlet 103 of the apparatus A coincide with the intake 102 of the following apparatus A.

5. Plant with modular apparatus with an evaporator-drier function according to any previous claim, characterized in that the passing of the material M from one apparatus A, to the following one is airtight and occurs by falling, and in which upstream of the plant at least one humidity sensor is provided that cooperates with detecting means of the weight of the material M and temperature, while downstream and at the end of the modular plant, an apparatus B is provided arranged to lower the energy accumulated by the material M, upstream thereof.

6. Plant with modular apparatus with an evaporator-drier function according to any of claims 1 to 3, characterized in that the association of a horizontally placed single modular apparatus A is provided, with an apparatus B that is arranged to lower the energy accumulated by the material M, in such a way that the modular apparatus A is overlying, parallel and spaced with respect to the underlying apparatus B so that from the overlying modular apparatus A the material M by simply falling and passing through the outlet 103, is arranged to be placed inside the apparatus B on a second fluidized bed 2 which extends within the apparatus B, which is without microwave generator devices 3, and to be hit by a forced airflow at a controlled temperature coming from an underlying secondary chamber 4 of the apparatus B communicating mono-directionally with a first chamber S of the apparatus B in the part underlying the second fluidized support and transportation bed 2.

7. Plant with modular apparatus with an evaporator-drier function according to any previous claim, characterized in that the fluidized bed 2 comprises a multi-layer material, wherein a lower layer is obtained in Kevlar while an upper layer is of a silicon-based material with micro holes.