WO2020053836A1 - Horizontal device for washing coffee with degraded mucilage - Google Patents

Abstract

The present invention relates to a horizontal mechanical washer for coffee with degraded mucilage. In particular, the invention describes a device for the coffee beneficiation process, which is used to remove the mucilage from the coffee cherries once the mucilage covering the beans has been degraded by means of the fermentation process or with the application of pectinolytic enzymes. The device comprises: i) a main horizontal shaft that supports a metering mechanism and a rotor with serrated agitators disposed along its length; ii) a cylindrical casing; iii) a receptacle or container; and iv) a water-injecting device.

Description

 HORIZONTAL DEVICE FOR WASHING COFFEE WITH DEGRADED MUCILAGO

I. FIELD OF THE INVENTION

The present invention is related to the field of apparatus or devices for processing coffee beans. In particular, the invention is associated with horizontal mechanical washing equipment used to remove the mucilage from the grain once it has been degraded by fermentation or with the use of pectinolytic enzymes.

II. DESCRIPTION OF THE STATE OF THE TECHNIQUE

In the wet coffee processing process, once the pulping and fermentation stages have been advanced, it is necessary to remove the remaining layer of degraded mucilage before starting the drying process. In order to remove the mucilage in the wet process, enzymatic, chemical and mechanical systems have been used in order to achieve optimal removal of the mucilage that allows grains to be obtained with the desired conditions and characteristics. Typically, the mechanical equipment developed in the art can be vertical flow (up or down) or horizontal flow; They remove the mucilage from the coffee by the effect of efforts that act on the surface of the beans, collisions between them and by friction between the beans and the mechanical elements inside the equipment. However, so far this process requires complex, heavy and expensive systems that demand high amounts of water and generate considerable mechanical damage to the grains, which in turn implies adequate disposal of the wastewater generated to reduce damage to ecosystems. In relation to mechanical washers, in the state of the art, equipment for demucilagination, cleaning and vertical washing of coffee are known. In general, such devices have two axes, one vertical where a rotor is supported with metal fingers, and the other horizontal that drives the coffee beans from a hopper towards the vertical axis. Similarly, these devices include features such as an outlet channel for washed and demucilaginated coffee beans and a structure with trays to collect the wastewater generated in the process. However, according to this particular configuration, the use of two axes at 90 ° requires either the use of two motors or the use of non-parallel inter-axle transmission systems, which imply a much heavier and more complex structure that is suitable to support them, which acts to the detriment of the handling and movement capacity of the device. The above not only implies higher equipment costs, but also the interaction of coffee with an extensive and vertical processing circuit results in greater mechanical damage to the beans, making a part of the volume of coffee treated in this type of devices is damaged by the same interaction generated by the rotating mechanical elements, not complying with the quality requirements demanded by users.

Now, there are in the art developments of demucilaging devices and washers with other configurations that have tried to simplify the process by having a single axis of horizontal arrangement and, typically, a rotor with stirring blades that move the coffee beans inside a casing, as mentioned, for example, in the academic textbook by Clarke et al. ¹ However, these devices, being more portable and having a reduced size, increase the possibility of generating mechanical damage to the grains. Indeed, it has been found that a wrong dimensioning of the stirrer blades and the casing in this type of device can lead to the coffee beans being trapped between the elements of the machine and consequently mistreated. The above is also due to a

¹ RJ Clarke and R. Macrae, 1987. Coffee Technology Volume 2. Elsevier Science Publishers LTD. ISBN 13- 978-94-010-8028-6 Pag. 19. non-uniform distribution of coffee at the entrance of the washer that generates undesired accumulations, preventing the full quality of washing that the device can reach.

Indeed, there is currently a need for horizontal equipment that can not only be easily managed and operated in the field by small and medium producers, but also provides a mechanical washing process that generates minimal damage to the grain of coffee, increasing the quality and quantity of the product obtained at the end of the washing process.

Thus, although the prior art has sought solutions to the technical problem related to the need to provide equipment that minimizes the mechanical damage of the coffee bean during the washing process, there are still no horizontal device configurations with the characteristics described here.

III. GENERAL DESCRIPTION OF THE INVENTION

The present invention relates to a horizontal configuration device for washing coffee with degraded mucilage. In general, the device of the present invention comprises: i) a horizontal main axis that supports a metering mechanism, a conical section with vanes and a rotor with toothed agitators arranged along its length; ii) a cylindrical casing; iii) a container or container; and iv) a water injector device. The special configuration of such mechanisms favors a good removal of mucilage, incurring less mechanical damage to the processed grain.

IV. DESCRIPTION OF THE FIGURES. Figure 1: Illustrates a preferred embodiment of the horizontal device for washing coffee with degraded mucilage.

Figure 2. Illustrates the way in which the mechanical elements are connected to the interior of the device in the preferred embodiment.

Figure 3. Illustrates in detail the configuration of the drive mechanism, the conical section and the rotor in the preferred embodiment.

Figure 4. Illustrates a sectional view of the scrubber showing the location of the toothed rotor in relation to the cylindrical casing.

V. DETAILED DESCRIPTION OF THE INVENTION.

The present invention relates to a horizontal mechanical coffee washing device with degraded mucilage whereby it is possible to remove mucilage from coffee incurring minimal mechanical damage to the bean.

As shown in figure 1, according to the invention, the device disclosed here comprises: a main shaft (1), which supports a metering mechanism (3), a conical section with vanes (4) and a rotor (2) ; a cylindrical casing (9) with holes; a container or container (18); and a water injector device (6), where the ratio between the outer diameter of the rotor (2) and the diameter of the cylindrical casing (9) that covers it is between 0.75 and 0.85.

According to a preferred embodiment of the invention, the coffee beans to be processed are deposited in the container or container (18). There, the pulped coffee is deposited in a first stage and fermentation is allowed to occur, which can occur naturally; mucilage can also be broken down by applying enzymes pectinolytics. Likewise, said container or container (18) has an opening in the bottom, which allows the coffee with degraded mucilage to be discharged by gravity by means of the actuation of a perforated sliding gate (14).

The perforated sliding gate (14) is in a preferred embodiment mounted on guides or rails that allow its lateral displacement in the direction of said guides or rails. Preferably, said perforated sliding gate (14) has holes (13) of between 4 mm and 5 mm in diameter that cover between 30% and 45% of its area. Holes (13) are preferably substantially circular.

According to this embodiment of the invention, when the gate (14) is in a first position, the drainage of the fluids and the retention of the grains are allowed. Additionally, it is possible to control the flow of coffee entering the machine by modifying the degree of opening of said gate (14).

Figure 2 shows as in preferred embodiments, the sliding gate (14) is connected to a vertical conduit (12), which can have the configuration of a hopper, by means of which the coffee beans are carried from the container or container ( 18) to the central body of the device.

Now, preferably, the central body of the device is connected by means of a main axis (1) arranged horizontally, which is supported by bearings and bearings (5) embedded in the front and rear covers of the device. The diameter of said axis (1) will be determined by the static and dynamic loads that the device must support, which will depend on the coffee processing capacity that is required. In this way, said main shaft (1) is coupled to a gear or pulley transmission means which in turn is connected to a motor (16), which provides the power necessary to promote rotation of the shaft (1) and allow the operation of the device. In this regard, it is important It should be noted that the device can be powered by a low-power motor, which means that it is possible to use conventional motors connected to the national domestic network or solar panels in the device. Similarly, it is located on the side of the housing, which allows it to be coupled and uncoupled quickly and easily.

Figure 3 shows, according to this embodiment, that the main shaft (1) supports the following elements: i) the dosing mechanism (3); ii) the conical section (4); and iii) the rotor (2), which will be described in detail later.

During the operation of this embodiment of the invention, once the coffee falls by gravity from the container or container (18) through the vertical conduit (12), it is deposited in a first horizontal cylindrical section where the dosing mechanism (3) is located. ) coupled to the main axis (1), which displaces the grains in the horizontal direction and delivers them to the conical section (4). Said dosing mechanism (3) can be any mechanical element that allows the grains to be displaced inside the device, however, in the preferred embodiment of the invention, this corresponds to a screw (3) with a rounded edge. In a preferred embodiment of the invention, there is a tolerance of between 0.5 to 1.0 mm of the dosing mechanism (3) in relation to the cover where it is located and a step of between 20 to 30 mm. Similarly, the diameter of the dosing auger (3) has a ratio of 0.90 to 0.99 relative to the diameter of the housing where it is located. The foregoing guarantees that, in this first stage of transport, the mechanical damage to the coffee beans is minimal.

After being transported by the dosing mechanism (3), the coffee passes through a conical section (4) before reaching the rotor (2). Preferably, the ratio of the largest diameter to the smallest diameter of the conical section (4) is between 3.7 and 4.0. In the same way, this element has, along its surface, a plurality of equidistantly distributed blades which allow a uniform distribution of coffee to the rotor in the washing chamber. In general, it has been found that guaranteeing an even distribution of coffee at the inlet of the scrubber, in the horizontal mechanical washing devices, is a very important factor to avoid undesired accumulations that cause mechanical damage to the beans. Particularly, in a preferred embodiment, the conical section has 3 blades welded on its surface distributed approximately every 120 °.

Now, as previously mentioned, the conical section (4) delivers the coffee uniformly to the rotor (2) in the washing chamber. In particular, this rotor, which is coupled integrally to the main shaft (1), comprises a plurality of toothed stirrers arranged along its circumference and its length. In a preferred embodiment, said stirrers are 12 or more. Under the context of the present invention, the aforementioned solid coupling should be understood as a type of union that encourages the shaft (1) to drive the rotor and allow it to rotate, for example, by means of a coupling of square cross section between the two. The ratio of the outer diameter to the inner diameter of the toothed stirrer rotor is between 1.25 to 1.35.

On the other hand, figure 4 shows the configuration of the washing chamber (15), which comprises a cylindrical casing (9) that covers the entire length of the rotor (2) and is located concentric to the main axis (one). In particular, said cylindrical casing comprises holes (11), which allow the water with mucilage to leave the cylindrical casing and the coffee beans without mucilage remain inside. Now, a factor of vital importance to reduce the mechanical damage generated by the rotor agitators corresponds to the relationship between the outer diameter of the rotor (2) and the diameter of the cylindrical casing (9) that covers it. In particular, it has been found that the optimal ratio that decreases the mechanical damage to the grains for this type of device is between 0.75 and 0.85. On the other hand, in a preferred embodiment, the holes (11) of the casing (9) are between 4 mm and 5 mm in diameter and cover an area of between 35% to 45% of the casing, being in some configurations evenly distributed throughout the entire housing area and others, concentrated only in the middle of its area. Likewise, the cylindrical casing is protected by a metal cover, which includes, in a preferred embodiment, removable side guards (10) that allow inspection of the interior of the device and proper maintenance when required.

In accordance with this embodiment of the invention, the washing chamber (15) requires a constant injection of water that favors the separation of the mucilage and the washing of the grains. For this purpose, there is a water injector device (6) made up of a pump, for example, a submersible pump. Such a pump propels the water from a reservoir, such as a tank (17), through an inlet hole located at the top of the scrubber cover (15). In a preferred embodiment of the invention, the injector device (6) is connected to a tank (17) with a direct acting float valve that maintains the appropriate level of water in the tank and ensures that the water flow is provided. in the range required for the correct operation of the scrubber (15). In this way, as the coffee advances inside the washing chamber (15), the mucilage is expelled through the openings in the housing due to the centrifugal force generated by the rotor and the added water.

Once the mucilage is removed by the combined effect of the action of water, the friction between the coffee beans as they advance through the free space left between the toothed agitators and the inner wall of the cylindrical housing, the flow of water supplied and the centrifugal force generated by the rotor, the coffee without mucilage passes through a discharge gate (8) located at one end of the device, where it can finally be collected. In particular, coffee leaves the device with a mucilage removal of over 95% and a very low mechanical damage of between 0.03 and 0.2%, thus reaching the appropriate characteristics and conditions for its subsequent use. On the other hand, the wastewater accumulates by gravity flowing to an outlet opening (21), which in a preferred embodiment consists of a channel connected to an outlet duct, and is subsequently mixed with the coffee pulp in relation 2 : 1 achieving 100% retention of these and 100% control of environmental contamination. Likewise, the device has a metal structure or chassis (20) that supports the aforementioned components, and that may also comprise additional elements such as wheels (19), handles or handles (7) that facilitate their movement. Additionally, in cases where the container or container (18) requires it, the chassis (20) may have additional support structures.

The device of the invention advantageously allows the processing of different amounts of coffee. In one embodiment, the device disclosed here allows processing between 300 kg / h and 500 kg / h of washed coffee. However, the modality that has been described is not limiting and the technical conditions inside the device, such as the number and geometry of the blades, the lengths of the rotor, impeller and cylindrical casing, the operating speed, the power of the motor, pump type, and, in general, the dimensions of the device may vary depending on the processing capacity required.

List of parts

(1) main shaft

 (2) rotor

 (3) dosing mechanism

 (4) conical section

 (5) bearings

 (6) water injector device

(7) handle with handle

 (8) discharge gate

 (9) cylindrical housing

 (10) side guards

 (11) holes in the cylindrical housing

(12) vertical duct (hopper)

 (13) slider gate holes

(14) perforated slide gate

(15) scrubber

 (16) motor

 (17) water tank

 (18) container or container

 (19) wheels

 (20) chassis

 (21) outlet opening

Claims

1. A horizontal pulping coffee washing device with degraded mucilage, comprising: a. a main shaft (1), which supports a metering mechanism (3), a conical section with vanes (4) and a rotor (2);  b. a cylindrical casing (9) with holes;  c. a container or container (18); Y  d. a water injector device (6); where the pulped coffee with degraded mucilage is fed to the rotor (2) by means of the doser (3) and the conical section with blades (4), and the rotor has toothed agitators arranged along its length and is located concentrically inside a cylindrical casing (9) with a ratio between the diameter of the rotor and the diameter of the casing between 0.75 and 0.85. 2. The horizontal coffee washing device according to claim 1 wherein between the container or container (18) and the dosing mechanism there is a perforated sliding gate (14), which when closed, allows the drainage of fluids and the retention of the beans and, when open, allows the discharge of coffee by gravity. 3. The horizontal coffee washing device according to claim 2 wherein the sliding gate has holes (13) of between 4.0 and 5.0 mm in diameter covering an area of between 30 and 45% of the total area of the gate. 4. The horizontal coffee washing device according to any of the preceding claims, wherein when the sliding gate is open it allows the flow of the coffee beans to the dosing mechanism, at the moment the process is to start washing. 5. The horizontal coffee washing device according to any of the preceding claims, further comprising a motor (16) connected to the main shaft (1).  6. The horizontal coffee washing device according to any of the preceding claims, further comprising a channel connected to an outlet duct through which the waste water (mucilage and used water) are disposed. 7. The horizontal coffee washing device according to any of the preceding claims wherein the dosing mechanism (3) is a worm screw. 8. The horizontal coffee washing device according to claim 7, where the diameter of the dosing auger (3) has a ratio of 0.90 to 0.99 relative to the diameter of the housing where it is located. 9. The horizontal coffee washing device according to claims 7 or 8 wherein the worm screw has a pitch of 20 to 30 mm. 10. The horizontal coffee washing device according to any of the preceding claims wherein the ratio of the largest diameter to the smallest diameter of the conical section (4) is between 3.7 and 4.0 11. The horizontal coffee washing device according to any one of the preceding claims wherein the conical section (4) has 3 or more blades distributed equidistant along its circumference. 12. The horizontal coffee washing device according to any of the preceding claims wherein the holes in the cylindrical casing (9) are between 4.0 and 5.0 mm in diameter. 13. The horizontal coffee washing device according to any of the preceding claims, wherein the holes of the cylindrical casing (9) cover 35 to 45% of the area of said casing. 14. The horizontal coffee washing device according to any of the preceding claims, wherein the holes in the cylindrical casing (9) are found only in the middle of the casing area. 15. The horizontal coffee washing device according to any of the preceding claims, wherein the toothed stirrer rotor (2) has a ratio between the external diameter and the internal diameter of between 1.25 to 1.35. 16. The horizontal coffee washing device according to any of the preceding claims wherein the water injector device (6) comprises a submersible pump.