TW202142131A - System for roasting coffee grains - Google Patents

Abstract

Described is a system (100) for roasting coffee grains comprising a combustion chamber (1) which is able to heat air; a rotary drum (3) for roasting coffee grains; a first connecting conduit (4) between the combustion chamber (1) and the rotary drum (3) for the passage of hot air from the combustion chamber (1) to the rotary drum (3) according to a feed direction (V); a decanting cyclone (8) connected, with a second conduit (9), to the rotary drum (3) in such a way as to receive a flow of hot air mixed with aerial and/or solid impurities from the rotary drum (3) and formed during the roasting; the system (100) also comprises a tubular body (10) with two channels (11, 12) positioned on the first connecting conduit (4) between the combustion chamber (1) and the rotary drum (3); the tubular body (10) is equipped with a first (13) and second (14) valve in such a way as to intercept, on a first channel (11) and with a first valve (13), the flow of hot air coming from the combustion chamber (1) and with the second channel (12) and the second valve (14) configured for intercepting air outside the system (100), at a temperature less than the flow of air arriving from the combustion chamber (1), and feeding it into the first conduit (4) downstream of the first valve (11), with respect to the feed direction (V), in such a way as to modify the temperature of the mixed flow of air entering the rotary drum (3).

Description

System for roasting coffee granules

The present invention relates to a system for roasting coffee particles, especially a system for roasting green coffee particles.

Some systems have been used for the roasting process of green coffee particles for a period of time, which can generate heat that reaches the coffee particles at a predetermined temperature via various methods such as convection, contact/conduction or radiation to roast the coffee particles.

Currently, the most common method is via convection with hot air, because coffee particles avoid direct contact with the heat source to allow the product to be roasted evenly. The coffee particles are then cooled (with ambient air or forced air) to allow the aroma to be enhanced.

The main elements of the system for roasting coffee particles via convection include: A combustion chamber for heating air (with a burner, which is designed to heat the air in the combustion chamber); A feed hopper for supplying green coffee particles; A rotating drum for roasting coffee particles (including a spiral or baffle for rotating the product), the rotating drum is connected on one side to a hopper for feeding the particles to be roasted, and on the other side Connected to the combustion chamber via a suitable pipe for the flow of hot air for baking the particles; A trough for cooling the roasted particles, the trough is provided with a suitable channel for discharging the roasted particles from the drum; A decanter cyclone, which is connected to the roasting drum so as to receive a stream of hot air mixed with air and/or solid impurities from the drum, that is, to separate from the coffee particles during the roasting step Solids (such as impurity films or particles); the cyclone is also equipped with a pipe for discharging and outflowing the air stream with impurities to the outside of the system.

A system for roasting coffee particles is known from the patent document EP3 178 330, which is very similar to the system just described.

Various elements of the system are provided with temperature probes connected to the control unit to allow measurement of the operating temperature inside the combustion chamber, connecting pipes, roasting drum and decanter cyclone, and according to the operating steps used to roast coffee particles To modify them.

This check is necessary because the roasting cycle must include the step of "drying" the pellets, which must be performed fast enough to allow the water present inside the coffee pellets to evaporate (the weight of the pellets decreases and the volume increases) And moisten the surrounding environment, that is to say, the rotating drum allows finer contact between coffee particles and the drum itself, and does not allow the so-called "scorch" phenomenon to occur during the actual roasting step, that is, due to the contact with the rotating drum Excessive contact of the metal wall results in the loss of surface material, while small blackened areas appear on the surface of the particles.

This is followed by the actual step of roasting the coffee particles, which must occur with a gradual and constant increase in the internal temperature of the coffee particles in order to obtain an optimal roast.

In other words, the air must first enter the drum and maintain a high temperature (at least 300/400°) in the drum to dry the coffee particles; then, it is necessary to lower the temperature inside the drum (about 200 to 220°), according to the presence Different types of coffee particles and different processing times to get the correct roasting of coffee particles.

However, based on this step, the above-mentioned type of baking system has several disadvantages.

The presence of a gas burner for generating a flow of hot air directed to the drum requires a relatively long reaction time to change the temperature change to be carried out in the drum.

This factor, together with the precise number of times required for the correct roasting process, combined with the aforementioned temperature, may determine the low quality of the roasted coffee particles.

In addition, the step of drying the coffee particles determines the generation of a large amount of smoke (that is, air with a high impurity ratio), which is directed to the decanting cyclone for purification.

In this case, in order to get the correct purification of the environment, the temperature of the air stream will need to be raised to incinerate the impurities, but usually during this step, the burner must lower the temperature to allow the coffee particles to be properly roasted.

However, the increase in temperature may cause an incorrect process for roasting coffee particles.

Therefore, the outflow pipe must be equipped with one or more catalytic filters to retain solid particles and discharge cleaner air without increasing the temperature of the air.

The presence of these catalytic filters actually increases the overall cost of the system and makes it necessary to periodically inspect the filters at a higher frequency than the normal inspections performed on the system.

The object of the present invention is to provide a system for roasting coffee particles, which overcomes the above-mentioned disadvantages of the prior art.

More specifically, the object of the present invention is to provide a system for roasting coffee particles, which can prevent thermal transients in the roasting drum, that is, maintain the required air temperature in a regular and continuous manner.

Another object of the present invention is to provide a system for roasting coffee particles, which can speed up the roasting step, while maintaining a high final quality of the product, while reducing the total cost of the system and its maintenance.

These objectives are fully achieved by the system for roasting coffee particles according to the present invention described in the appended claims.

With reference to the drawings, especially FIG. 1, the system for roasting green coffee particles according to the present invention is marked as 100 as a whole.

The main part of the system 100 includes a combustion chamber 1 provided with a unit 2 for generating heat capable of heating air (for example, but not limiting the scope of the present invention, a gas burner).

The system 100 also includes a rotating drum 3 for roasting coffee particles.

The system 100 includes a first pipe 4 for connecting between the combustion chamber 1 and the rotating drum 3 for transferring hot air from the combustion chamber 1 to the rotating drum 3 along a supply direction V.

The system 100 also includes a decanting cyclone 8 which is connected to the rotating drum 3 via a second pipe 9 so as to receive the air and/or solid impurities mixed from the rotating drum 3 and formed during baking. Hot air flow.

As shown in the figure, the system 100 also includes at least one feeding hopper 5 connected to the rotating drum 3 for supplying particles to be baked.

In addition, the system 100 includes a tank 6 for cooling the roasted particles, and the tank is provided with a channel 7 for discharging the roasted particles from the rotating drum 3.

As shown again in the figure, the system 100 includes a tubular body 10 with two passages 11, 12, which are located on the first pipe 4, for performing operations between the combustion chamber 1 and the rotating drum 3. connect.

The tubular body 10 is provided with a first valve 13 and a second valve 14, so that the first valve 13 can be used on a first passage 11 to intercept the flow of hot air from the combustion chamber 1, and the second passage 12 and the The second valve 14 is configured to intercept air whose temperature outside the system 100 is lower than the temperature of the air flow from the combustion chamber 1, and to supply it to the downstream of the first valve 11 in terms of the supply direction V In the first duct 4, the temperature of the mixed air flow entering the rotating drum 3 can be changed.

A control device 15 is connected to the first valve 13 and the second valve 14, for changing their positions in the corresponding first passage 11 and the second passage 12, so as to be able to respond to the required temperature in the rotating drum 3 To change the corresponding flow rate of the airflow.

In other words, the correct baking temperature can be obtained in the rotating drum, regardless of the temperature in the combustion chamber.

In this way, the combustion chamber can operate in a constant steady state, because the temperature in the drum is adjusted downstream of the combustion chamber via a two-way system with individual valves present on the first pipe.

As shown in the figure, the control device 15 has a device for connecting to the first valve 13 and the second valve 14 so as to be able to operate between a number of intermediate operations including a first end operating position and a second end operating position. The device 16 for simultaneously moving the first valve 13 and the second valve 14 between positions (one of which is visible in Figure 4), in the first end operating position, the first valve 13 is positioned to be fully closed for supply The first duct 4 of the air flow from the combustion chamber 1, and at the same time, the second valve 14 is positioned to keep the second passage 12 fully open (FIG. 3). In the second end operating position, the first The valve 13 is positioned to keep the first duct 4 fully open for supplying air flow from the combustion chamber 1, and at the same time, the second valve 14 is positioned to completely close the second passage 12 (Figure 5).

In this way, the temperature can be adjusted from the rapid cooling of the drum (the valve structure of FIG. 3) to the rapid heating of the drum (the valve structure of FIG. 5), or in an adjusted manner in the configuration shown in FIG. 4 Change the temperature in the drum.

It should be noted that the tubular body 10 with two channels 11, 12 is "T"-shaped, and is provided with two-stage channels with a circular cross-section.

In view of this, the first section of the passage 11 defines a coaxial joint on the first pipe 4 between the combustion chamber 1 and the rotating drum 3 (see FIG. 2).

In an exemplary non-limiting embodiment according to the present invention, each of the first valve 13 and the second valve 14 is a butterfly valve, and each is twisted on the corresponding first passage 11 and the second passage. 12 so as to form a circular plate capable of rotating around a central axis.

Preferably, the control device 15 includes an actuator 17 (such as an electromechanical type and shown schematically in FIG. 2), which is associated with the tubular body 10 and is provided for connection to the first valve 13 And the second valve 14 to allow a device 16 for synchronous movement of the first valve 13 and the second valve 14.

In view of this, the actuator 17 is externally associated with the second passage 12 and is provided with the connecting device 16, which includes a motor drive shaft 18 connected to the second valve 14 to allow the second valve 14 Controlled rotation.

One end of a first connecting rod 19 is keyed to the shaft 18, and the first connecting rod 19 is twisted on a shaft 20 for driving and connecting to a second connecting rod 21, which is connected to The first valve 13 can be activated by a single actuation of the motor drive shaft 18 to allow simultaneous movement of the first valve 13 and the second valve 14.

The system 100 also includes a suction unit 22, which is associated with the decanting cyclone 8 and is configured for air recirculation, so that impurities in the air can be picked up from the decanting cyclone 8 and used A third pipe 23 transports them to the combustion chamber 1 to allow the waste heat from the rotating drum 3 to be recovered and to reduce the solid particles generated in the combustion chamber 1 to pass through a flue exhaust duct 24.

It should be noted that the suction unit 22 generates a negative pressure loop in the form of a composite closed loop at least from the first pipe 4, from the rotating drum 3, and from the decanting cyclone 8, so as to allow the flow from the first pipe Constant and correct flow of hot air and/or ambient air in the duct 4.

The system 100 also includes a unit 25 for assisting in the introduction of air which is introduced into the combustion chamber 1 to obtain a post-combustion stage of the smoke to be guided to a flue exhaust duct 24 when needed.

In addition, the system 100 includes a command and control unit 26 which is connected to at least the combustion chamber 1 and the first valve 13 and the second valve 14 to allow the air flow in the rotating drum 3 and its temperature to be adjusted.

In view of this, the command and control unit 26 is connected to at least a first temperature sensor 27 located in the combustion chamber 1 and a second temperature sensor located downstream of the tubular body 10 on the first pipe 4 28, and a third temperature sensor 29 located in the rotating drum 3.

In this way, the command and control unit 26 is always updated according to the current operating temperature, and can modify, for example, the position of a valve, or increase or decrease (if necessary) the temperature in the combustion chamber.

A system constructed in this way brings many advantages, including: Optimize the baking cycle due to the precise control of the airflow and its temperature in the drum; The valve on the first pipe isolates the combustion chamber from the baking drum, so as to allow the combustion chamber to maintain a high and constant temperature; The existence of the negative pressure system makes it possible to optimize and accelerate the air flow entering and leaving. The air flow with impurities is directly discharged into the combustion chamber by the system. Due to the high temperature and the possibility of a post burner, It can directly reduce particulates and related emissions towards the flue exhaust duct.

The latter function allows the system without a catalytic filter.

1: Combustion chamber 2: unit 3: Rotating drum 4: The first pipeline 5: Feed hopper 6: Slot 7: Channel 8: Decanting cyclone 9: The second pipeline 10: Tubular body 11: The first channel 12: Second channel 13: The first valve 14: Second valve 15: Control device 16: Device, connection device 17: Actuator 18: Motor drive shaft 19: The first link 20: axis 21: The second link 22: Suction unit 23: The third pipeline 24: Exhaust duct 25: unit 26: Command and Control Unit 27: The first temperature sensor 28: The second temperature sensor 29: The third temperature sensor 100: System V: Supply direction

The main features of the present invention will become more apparent through the following detailed description of a preferred and non-limiting example of the present invention. The example is shown as an example in the attached drawings, in which: Figure 1 is a diagram of a baking system according to the present invention; Figure 2 is a schematic front view relative to detail A of Figure 1, in which some parts are shown in cross section, and other parts are cut to better show some technical details, and refer to the T-shaped tubular body with valve elements; Figures 3 to 5 show corresponding schematic cross-sections of the valve element inside the cylindrical tubular body of Figure 2 in corresponding operating positions.

1: Combustion chamber

2: unit

3: Rotating drum

4: The first pipeline

5: Feed hopper

6: Slot

7: Channel

8: Decanting cyclone

10: Tubular body

11: The first channel

12: Second channel

13: The first valve

14: Second valve

15: Control device

22: Suction unit

23: The third pipeline

24: Exhaust duct

25: unit

26: Command and Control Unit

27: The first temperature sensor

28: The second temperature sensor

29: The third temperature sensor

100: System

V: Supply direction

Claims (10)

A system for roasting coffee particles, at least including: A combustion chamber provided with a unit for generating heat capable of heating air; A rotating drum for roasting coffee particles; A first pipe for connecting between the combustion chamber and the rotating drum, so as to transfer hot air from the combustion chamber to the rotating drum along a supply direction; A tubular body with two passages, the tubular body is positioned on the first connecting pipe between the combustion chamber and the rotating drum; the tubular body is provided with a first valve and a second valve, so that the The first valve is used on the first passage to intercept the hot air flow from the combustion chamber, and the second passage and the second valve are configured to intercept the temperature outside the system lower than the temperature of the air flow from the combustion chamber , And supply it to the first pipe downstream of the first valve in terms of the supply direction, so that the temperature of the mixed air flow entering the rotating drum can be changed; A control device, connected to the first valve and the second valve, is used to change their positions in the corresponding first and second channels, so that the airflow can be changed according to the required temperature in the rotating drum Corresponding flow rate; It is characterized in that the control device is connected to the first valve and the second valve so as to be able to simultaneously operate between a plurality of intermediate operating positions including a first end operating position and a second end operating position. The device for moving the first valve and the second valve, in the first end operating position, the first valve is positioned to completely close the first pipe for supplying the air flow from the combustion chamber, and at the same time, the The second valve is positioned to keep the second passage fully open, and in the second end operating position, the first valve is positioned to keep the first pipe for supplying air flow from the combustion chamber fully open, and at the same time, The second valve is positioned to completely close the second passage. The system according to claim 1, wherein the tubular body containing two passages is T-shaped and is provided with two passages having a circular cross section; the first passage is defined on the first pipe for A coaxial joint connecting the combustion chamber and the rotating drum. The system according to claim 1 or 2, wherein the first valve and the second valve are both butterfly-shaped, and are twisted on the corresponding first and second channels so as to be able to rotate around a central axis The formation of a circular plate. The system according to any one of claims 1 to 3, wherein the control device comprises an actuator, the actuator is associated with the tubular body and is provided for connecting to the first valve and the second valve. A device that allows the first valve and the second valve to move synchronously. The system according to claim 4, wherein the actuator is externally associated with the second passage and is provided with the connecting device, which includes a motor drive shaft connected to the second valve to allow the second valve The controlled rotation of the shaft; the end of a first connecting rod is keyed on the shaft, and the first connecting rod is twisted on a shaft for driving and connecting to a second connecting rod, the second connecting rod is connected To the first valve, a single actuation of the motor drive shaft allows simultaneous movement of the first valve and the second valve. The system according to any one of claims 1 to 5, which comprises a decanting cyclone connected to the rotating drum via a second pipe so as to be able to receive air and/or solid impurities from the rotating drum A stream of hot air that is mixed and formed during baking. The system according to claim 6, which comprises a unit associated with the decanting cyclone and configured for recirculation of air, so that impurities in the air can be picked up from the decanting cyclone, and A third pipe is used to transport them to the combustion chamber to allow the waste heat from the rotating drum to be recovered and to reduce the solid particles generated in the combustion chamber to pass through a flue exhaust duct. The system according to claim 7, wherein the suction unit generates a negative pressure circuit in the form of a composite closed circuit from the combustion chamber, from the rotating drum, and from the decanting cyclone, so that A constant and correct flow of hot air and ambient air from the first duct can be allowed. The system according to any one of claims 1 to 8, which includes a unit for assisting in the introduction of air that is introduced into the combustion chamber to obtain a trail of smoke that will be directed to a flue when needed Burning phase. The system according to any one of claims 1 to 9, which includes a command and control unit connected to at least the combustion chamber and the first valve and the second valve to allow adjustment of the air in the rotating drum Flow and its temperature; the command and control unit is connected to at least a first temperature sensor located in the combustion chamber, a second temperature sensor located downstream of the tubular body on the first pipe, and the rotating drum A third temperature sensor inside.

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