BR-102024017889-A2 - Fixed bed coffee dryer for small and medium-sized producers.

Abstract

The object of this patent of invention was developed to improve a static coffee dryer through a fixed bed solution with uniform air distribution in the grain mass, by means of vertical deflectors (12) and horizontal deflectors (5), combined with a plurality of air distributors (6) positioned under the inclined bottom (3). With automated control of the drying air temperature, carried out by a PID controller, applied to a reduced size structure, allowing small producers to obtain superior quality in their processing. Additionally, it provides facilities for loading and unloading the dryer, in order to homogenize the drying by moving the product in a reduced way, reducing the dispersion of the final moisture.

Inventors

• Francisco Maria Ayala Barreto

Assignees

• COOL SEED INDÚSTRIA E COMÉRCIO DE EQUIPAMENTOS AGRÍCOLAS LTDA

Dates

Publication Date

20260317

Application Date

20240830

Claims (3)

1. 1. FIXED BED COFFEE DRYER FOR SMALL AND MEDIUM PRODUCERS, wherein the grain dryer (SG) is equipped with a dryer base (11), which contains a tunnel (8) connecting the indirect fire furnace to the air inlet pipes (21), and equipped with an indirect fire furnace (20); further characterized by having a metallic dryer body (2), with a hollow polygonal prismatic shape of 12 sides, formed by a metallic structure and covered by metal sheets, containing a metallic fan duct (9) with a rectangular prismatic shape, positioned on the outside of the dryer body (2), aligned with the base; containing a metallic product discharge chute (10) with a semi-cylindrical shape, positioned on the lower outside of the dryer body (2) on the opposite side of the fan duct (9); containing a chute valve (24), positioned at the junction between the product discharge chute (10) and the dryer body (2); contains an inclined structure (3), metallic and with a shape similar to the dryer body (2), positioned internally in an inclined manner, in which the highest part is located above the cutout of the fan duct (9) and the lowest part is located under the cutout of the product discharge chute (10); contains a bottom plate (22), metallic, with a shape similar to the inclined structure (3), has a plurality of small holes for the passage of air from the drying air plenum (4), which is the lower part of the dryer body (2), to the upper part (drying chamber); contains vertical deflectors (12), trapezoidal shaped metal plates, located at the beginning of the cutout of the fan duct (9) closer to each other and forming a “V” towards the center of the dryer body (2); contains a plurality of air distributors (6), metal angle brackets in the shape of “L”, with fixing flanges at both ends, positioned with their opening facing the product discharge chute (10), positioned in rows, below the inclined structure (3), one row having a lateral displacement in relation to the other, the angle brackets have different heights according to their positioning in relation to the inclined structure (3); contains horizontal deflectors (5), made of metal, the first with a width equal to the width of the fan duct (9) and positioned internally slightly inclined near the entrance to the dryer body (2), the second is positioned horizontally, with a trapezoidal shape, and positioned between the vertical deflectors (12); equipped with a centrifugal fan (1), positioned with its outlet duct in the fan duct (9), equipped with an air inlet pipe (21) cylindrical pipe in the shape of a “T”, with one of its upper connections connecting to the centrifugal fan (1), its lower end fixed to the tunnel (8) of the dryer base (11), containing an air register (7) at its lower end, containing a damper (13) at its end opposite the centrifugal fan (1).
2. 2. FIXED BED COFFEE DRYER FOR SMALL AND MEDIUM PRODUCERS according to claim 1, with an adequate drying air flow rate, characterized by being between 0.8 and 1.5 m³/h per liter of coffee.
3. 3. INTRODUCED IN A FIXED BED COFFEE DRYER FOR SMALL AND MEDIUM PRODUCERS according to claim 1, wherein the control of the drying air temperature is characterized by being actuated by a damper (13), controlled by a PID (proportional-integral-derivative).

Description

Field of invention [001] This invention relates to a coffee dryer for small producers, applied in the field of agriculture, specifically in the area of grain drying, with the purpose of drying coffee beans, which may be freshly harvested, with the advantages of having a higher unit air flow rate, simpler to manufacture and install, with a better distribution of the drying air in the mass of beans inside the dryer, ensuring better uniformity of drying and greater efficiency. Fundamentals of the invention [002] As is known to those in the technical field related to grain and seed drying, particularly coffee, current processes involve initial drying on ground or suspended drying patios and final drying in rotary or vertical vibratory dryers. In Brazil, coffee production areas of small producers are generally located in mountainous terrain and involve manual harvesting. Drying is done on patios with all the difficulties of climate and labor, as the product must be moved more than 12 times a day. There are increasing labor shortages, and coffee production in small areas has proven arduous and less profitable. Furthermore, investment capacity is limited. An alternative that would make the activities of small producers at least twice as profitable is the production of higher quality coffees, thus allowing them to sell their product at a better price; however, this requires appropriate farming and post-harvest techniques. [003] Small producers are usually associated with Cooperatives that provide the inputs and agronomic knowledge for good soil and plant management, however, they lack support for post-harvest, leaving only the drying yard with all the quality problems in coffee and labor in terms of technology. [004] Traditional static dryers have existed for many years that use a forced ventilation system to circulate hot air through the grains. The hot air can be generated by gas, wood, or electric burners. This air is distributed through the grain mass via ducts or openings at the bottom of the structure. [005] Over the years, dynamic coffee drying systems have been developed, in which the beans are moved continuously during the drying process, ensuring a more uniform distribution of heat and more precise control of humidity. However, these dryers are more complex and expensive to operate and maintain than static dryers. The constant movement of the beans can also cause greater wear, potentially resulting in more broken or damaged beans. [006] Searching Brazilian and international patent databases revealed the following findings. [007] The object of patent BR 10 2019 020929 1 discloses equipment for drying coffee and grains in general, which uses a furnace that has a wall of heat pipes, characterized by the dryer furnace comprising looped heat pipes with the evaporator part arranged on all the side walls of the furnace combustion chamber and having a condenser formed by a bundle of tubes at the other end of the loop and the two parts being connected by intermediate vapor and liquid tubes. [008] The equipment in patent BR 10 2019 020929 1, despite being a static drying system with vertical airflow, does not provide control of the drying air temperature and presents uneven distribution of the drying air in the grain mass. [009] The object of patent BR 20 2021 005411 0 reveals an improvement in a semi-static coffee dryer with a fixed and movable layer, heated by a furnace monitored by a thermometer. The hot air flow passes through the micro-holes in the metal plates of the funnel and through the micro-holes in the hatches, which, when closed, act as a static chamber, as they fit together in a bellows shape. The beans remain there for the first drying stage. Subsequently, the articulated hatch system is manually activated, which performs the tumbling of the beans, individually by compartment in the first stage, and together in the second stage. When the beans are already in the funnel, the auger is moved by means of a motorized drive, which redirects them to the upper part, and so on until the last hatch with beans tumbles, then starting the second stage, now with the tumbling of all the hatches together, as the beans are already slightly dry, which prevents their Encrustation occurs when the final flow of hot air is applied with the screw conveyor activated, resulting in homogeneous drying. [010] The equipment in patent BR 20 2021 005411 0 has the limitation of not solving the air distribution problem of static systems, in addition it uses a rectangular shape which is unfavorable to uniform drying, since there will be little or no airflow for drying in the corners. [011] The subject of patent CN115654858A discloses a small grain dryer that is provided with a drying tower and a heat pump condensation dehumidification unit. The drying tower is provided with a drying feed port, a drying discharge port, and a grain drying channel. A central air channel is arranged in the middle of the interior of the grain drying chann