FIELD OF THE INVENTION

The present invention concerns an apparatus and a process for roasting particulate material, such as coffee or cacao beans, grains, malt.

BACKGROUND OF THE INVENTION

Although the process of roasting particulate material, such as cacao or coffee beans, is used in large industrial plants, it remains an extremely delicate operation, requiring a particular expertise. The chemical composition of the material changes during roasting: its appearance, as well as the development of flavours and tastes, evolves during this operation. Furthermore, on contact with heat some elements disappear, while others combine.

According to solutions known in the industry, roasting takes place in a circular or cylindrical grill, called a roaster. This is an apparatus equipped with a permanently rotating drum so that the material, always moving, is roasted in a uniform way and without being burnt. The heat source must be regulated because the reactions evolve during roasting. At the end of the operation, the material must be cooled rapidly to interrupt the chemical processes.

During roasting, the particulate material must reach a uniform temperature within itself, so as to obtain the best possible quality. Several techniques are distinguished by their duration and by the amount of heat used. The traditional method operates at low temperature for a long time, entailing a small production quantity but obtaining the best quality. In contrast, industrial processes that allow faster production speeds are generally performed at higher temperatures, with the result that a portion of the material will be burnt, releasing less refined flavours.

The techniques described above are typically carried out according to the so-called batch or discontinuous method, producing batches of roasted material at regular intervals.

SUMMARY

The object of the embodiments of the invention is to provide an apparatus and a process for roasting particulate material in order to obtain a better quality roasted material. More particularly, the embodiments of the invention are intended to provide an apparatus and a process for roasting particulate material capable of being implemented industrially and of operating at low temperature, with low energy consumption, and with high production rates.

According to a first aspect of the invention, an apparatus is provided for roasting particulate material, such as coffee or cacao beans, grains, malt, said apparatus comprising:

a transport system configured for transporting a layer of particulate material through a treatment compartment comprising a first zone, one or more intermediate zones and a last zone, such that the particulate material passes consecutively through the first zone, the intermediate zones, and the last zone;

a first fluid generating unit configured for generating a first gas and/or steam flow through the first zone;

one or more intermediate fluid generating units configured for generating one or more intermediate gas and/or steam flows through the intermediate zone or zones;

a last fluid generating unit configured for generating a last gas and/or steam flow through the last zone;

a control system configured to control said first fluid generating unit, said intermediate fluid generating unit or units, and said last fluid generating unit, such that the layer of particulate material is preheated in the first zone, roasted in the intermediate zone or zones, and cooled in the last zone.

Existing solutions for roasting particulate material use the batch or discontinuous method, in which the particulate material is shaken in a drum while hot air is blown through it. One disadvantage of this process is that it requires a large amount of mechanical energy to keep the coffee beans moving in the drum for the entire duration of the batch. Another disadvantage of this process is that it requires working at high temperatures if high production rates are wanted, resulting in reduced quality.

These problems are solved according to the embodiments of the invention by arranging a system in which the particulate material is transported in layers, allowing continuous operation.

The present apparatus is divided into different zones, where each zone has a different temperature in order to reach a certain predetermined temperature within the particulate material in each zone, the heating being provided by gas and/or steam. The advantages of transporting a layer of particulate material through a treatment compartment comprising several zones are the reduction of the amount of mechanical energy needing to be supplied during roasting as well as the possibility of working at lower temperatures that can be adjusted so as to achieve optimal roasting, resulting in a better quality roasted material.

According to other embodiments, the first zone and/or the last zone may be absent from the treatment compartment, the latter being able to consist solely of one or more intermediate zones, such that the particulate material passes consecutively through the intermediate zones. Consequently, the first fluid generating unit and/or the last fluid generating unit may be absent from the roasting apparatus.

Thus, according to these embodiments, the control system can be configured to control said intermediate fluid generating units, such that the layer of particulate material is preheated in the first intermediate zone and roasted in the following intermediate zone or zones. As a result, the first intermediate zone fulfils the role of the first zone, and in the absence of the last zone the layer of particulate material can be cooled outside the treatment compartment, for example in ambient air.

According to a preferred embodiment, the transport system of the apparatus described above comprises feeding means configured to feed the particulate material such that the layer has a thickness which comprises not more than 10 particles of the particulate material, such as beans, preferably not more than 3 particles, and more preferably not more than 2 particles.

According to an exemplary embodiment, the feeding means is configured to feed the particulate material such that the layer has a thickness which is smaller than 100mm, preferably smaller than 20mm, and more preferably smaller than 15mm.

In this way, the determination of the maximum height of the layer of particulate material, that is to say the number of particles that can be superimposed without these particles adhering to each other, ensures a uniform temperature within all the particles. By providing a thin layer, it is easier to make the temperature within the particles more homogeneous.

According to a preferred embodiment, the transport system comprises a conveyor belt with a substantially flat surface which supports the layer of particulate material. The conveyor belt passes through the first zone, the intermediate zone or zones and the last zone, and is configured to allow the first gas and/or steam flow, the intermediate gas and/or steam flow or flows and last gas and/or steam flow to pass through the layer of particulate material that it supports. Thus, the translational movement given by the conveyor belt makes it possible to shed the mechanical work that is necessary in the batch method for shaking the particulate material in a rotating drum, which leads to a reduction in the mechanical energy supplied by the roasting apparatus.

According to a preferred embodiment, the transport system comprises two substantially parallel sheets between which the particulate material is transported, configured to allow the first gas and/or steam flow, the intermediate gas and/or steam flow or flows and the last gas and/or steam flow to pass through.

This embodiment offers the same advantage as the use of a conveyor belt, while generalising the manner in which the particulate material is transported. In the case of a conveyor belt like one with two parallel sheets, the porosity of these elements allows the gas and/or steam flow to circulate uniformly in each zone of the apparatus.

In a preferred embodiment, the transport system is configured to move the layer of particulate material at a substantially constant speed through the first zone, the intermediate zone or zones and the last zone.

Thus, the apparatus can be operated continuously to obtain a more or less constant production rate of roasted material.

According to an exemplary embodiment, the substantially constant speed is between lmm/s and lm/s.

Setting this speed gives the apparatus a degree of independence, and therefore an adaptable character. It makes it possible to have different production rates of roasted particulate material, so as to achieve production rates in the range of those of so called rapid roasting methods.

In a preferred embodiment, the first fluid generating unit of the apparatus is configured for generating the first gas and/or steam flow through the first zone, substantially perpendicular to the layer of particulate material. Likewise, the intermediate fluid generating unit or units are configured for generating the intermediate gas and/or steam flow or flows through the intermediate zone or zones substantially perpendicular to the layer of particulate material. Finally, the last fluid generating unit is configured for generating the last gas and/or steam flow through the last zone, substantially perpendicular to the layer of particulate material. Thus, the perpendicularity of the gas and/or steam flows relative to the layer of particulate material ensures that the particles of the layer of particulate material remain substantially immobile relative to the support of the layer, since no longitudinal force is applied.

According to a preferred embodiment, the treatment compartment, the first fluid generating unit, the intermediate fluid generating unit or units, and the last fluid generating unit as well as the control system form a substantially closed system, such that substantially no energy escapes from the substantially closed system.

Thus, designing a closed system makes it possible to reduce both the consumption of thermal energy and also the level of emissions of gas and/or roasting steam to the outside of the apparatus. Indeed, a difference between the batch method and the embodiments of the present invention is found in the emissions of gas and/or steam, which do not vary significantly in the continuous method, thus avoiding the pollutant emission peaks observed in the discontinuous method. As a result, the emissions treatment facilities can be optimally adjusted and operate at lower power levels, which makes it possible to provide excellent performance while still respecting the environment.

According to a preferred embodiment, the control system of the apparatus is configured to use at least a portion of the gas and/or steam flow that has passed through one of the zones for generating at least a portion of the gas and/or steam flow of another zone, preferably another zone upstream of said zone.

This heat recovery and recirculation system makes it possible to reduce both the consumption of thermal energy and the level of gas and/or steam external emissions. The use of at least a portion of the gas and/or steam flow that has passed through a zone downstream of the zone that recovers this flow has the advantage that the latter is at a higher temperature. Thus, the amount of heat recovered is greater.

According to a preferred embodiment, the intermediate zone or zones of the treatment compartment comprise at least a first intermediate zone and a second intermediate zone downstream of the first intermediate zone. The control system is configured to use at least a portion of the second intermediate gas and/or steam flow that has passed through the second intermediate zone for generating at least a portion of the first gas and/or steam flow and/or at least a portion of the first intermediate gas and/or steam flow, and vice versa. This embodiment customises the heat recovery and recirculation system to the intermediate zones of the treatment compartment. The present invention allows recirculation to occur from an intermediate zone to intermediate zones both upstream and downstream of the latter, not necessarily being adjacent to it. Indeed, depending on whether the process within the intermediate zone concerned is exothermic or endothermic, one or the other solution will be preferable.

According to a preferred embodiment, the intermediate zone or zones comprise a first intermediate zone and a second intermediate zone, and the intermediate fluid generating unit or units comprise: a first intermediate fluid generating unit configured for generating a first intermediate gas and/or steam flow through the first intermediate zone in a first direction that is substantially perpendicular to the layer of particulate material, and

a second intermediate fluid generating unit configured for generating a second intermediate gas and/or steam flow through the second intermediate zone in a second direction opposite to the first direction.

This arrangement of alternating circulation of gas and/or steam from one intermediate zone to the other facilitates the task of recovery and recirculation of these flows described by the previous embodiment, and can ensure a substantially homogeneous roasting of the different layers of particulate material.

According to a preferred embodiment, the treatment compartment of the apparatus has an even number of intermediate zones.

This characteristic is a direct consequence of the content of the two previous embodiments. Indeed, for optimum operation of recovery and recirculation of gas and/or steam flows, it is necessary that there are as many intermediate zones in which the flow circulates in one direction as there are intermediate zones in which the flow circulates in the opposite direction. Furthermore, in this way the layer of particulate material is subjected to an ascending flow for the same length of time as a descending flow, which guarantees a substantially homogeneous roasting, in an embodiment where the zones have the same length.

According to an exemplary embodiment, the treatment compartment of the apparatus has at least two intermediate zones, preferably four intermediate zones, and more preferably six intermediate zones. Thus, by increasing the number of intermediate zones, the roasting process can be optimised, and the quality of the roasted particulate material will be better. Indeed, the temperature gradient from one intermediate zone to another adjacent one can be reduced if the number of intermediate zones is increased.

According to a preferred embodiment, the control system is configured to control the temperature and/or the composition and/or the speed of the first gas and/or steam flow, of the intermediate gas and/or steam flow or flows and of the last gas and/or steam flow.

The regulation of these parameters gives the apparatus several degrees of independence, and therefore an adaptable character. Thus, the quality of the roasted particulate material can be more easily controlled, this quality being directly dependent on the value of these three parameters.

According to a preferred embodiment, the control system is configured to control the temperature of the first gas and/or steam flow to be between 45 °C and 150°C.

In this way, the first zone of the treatment compartment performs its role correctly, namely the preheating as well as the drying of the particulate material to be roasted.

According to a preferred embodiment, the control system is configured to control the temperature of the intermediate gas and/or steam flow or flows, and/or the temperature of the last gas and/or steam flow, to be between 150°C and 350°C.

In this way, the intermediate zone or zones of the treatment compartment perform their role correctly, namely the roasting of the particulate material. This temperature range corresponds to that of traditional roasting methods, with the advantage of a production rate that can reach that of rapid methods, as previously described.

According to a preferred embodiment, the control system is configured to control the temperature of the last gas and/or steam flow, to be between 10°C and 100°C.

In this way, the last zone of the treatment compartment performs its role correctly, namely the cooling of the roasted particulate material. According to a preferred embodiment, the intermediate gas and/or steam flow or flows comprise steam, and the control system is configured to control the relative humidity of the intermediate gas and/or steam flow or flows.

According to a preferred embodiment, at least one intermediate fluid generating unit is configured for generating a saturated and/or superheated steam flow through at least one intermediate zone, such as to perform a sterilisation and/or a pasteurisation of the particulate material.

Indeed, the advantage of steam over gas for roasting particulate material is that the use of saturated and/or superheated steam makes it possible to perform a sterilisation and/or a pasteurisation of the particulate material.

The person skilled in the art will understand that the above considerations and technical advantages with respect to embodiments of the roasting apparatus also apply to the corresponding embodiments of the process described below, mutatis mutandis.

According to a second aspect of the invention, a process is provided for roasting particulate material, such as coffee or cacao beans, grains, malt, said process comprising:

transporting, preferably continuously, a layer of particulate material consecutively through a first zone, one or more intermediate zones and a last zone;

generating a first gas and/or steam flow through the first zone;

generating one or more intermediate gas and/or steam flows through the intermediate zone or zones;

generating a last gas and/or steam flow through the last zone;

controlling said first gas and/or steam flow, said intermediate gas and/or steam flow or flows, and said last gas and/or steam flows, such that the layer of particulate material is preheated in the first zone, roasted in the intermediate zone or zones, and cooled in the last zone.

According to a preferred embodiment, the layer has a thickness which comprises not more than 10 particles of the particulate material, such as beans, preferably not more than 3 particles, more preferably not more than 2 particles.

According to an exemplary embodiment, the layer has a thickness which is smaller than 100mm, preferably smaller than 20mm, more preferably smaller than 15mm. According to a preferred embodiment, the layer of particulate material is transported at a substantially constant speed through the first zone, the intermediate zone or zones and the last zone.

According to an exemplary embodiment, the substantially constant speed is between lmm/s and lm/s.

According to a preferred embodiment, the first gas and/or steam flow is generated substantially perpendicular to the layer of particulate material; the intermediate gas and/or steam flow or flows are generated substantially perpendicular to the layer of particulate material; and the last gas and/or steam flow is generated substantially perpendicular to the layer of particulate material.

According to a preferred embodiment, the controlling comprises using at least a portion of the gas and/or steam flow that has passed through one of the zones for generating at least a portion of the gas and/or steam flow of another zone, preferably another zone upstream of said zone.

According to a preferred embodiment, the intermediate zone or zones comprise at least a first intermediate zone and a second intermediate zone downstream of the first intermediate zone. At least a portion of the second intermediate gas and/or steam flow which has passed through the second intermediate zone is used for generating at least a portion of the first gas and/or steam flow and/or at least a portion of the first intermediate gas and/or steam flow, and vice versa.

According to a preferred embodiment, the intermediate zone or zones comprise a first intermediate zone and a second intermediate zone. A first intermediate gas flow is generated through the first intermediate zone in a first direction and a second intermediate gas flow is generated through the second intermediate zone in a second direction opposite to the first direction.

According to a preferred embodiment, the number of intermediate zones is even.

According to an exemplary embodiment, the number of intermediate zones is at least two, preferably four, and more preferably six.

According to a preferred embodiment, the temperature and/or the composition and/or the speed of the first gas and/or steam flow, of the intermediate gas and/or steam flow or flows, and of the last gas and/or steam flow is controlled. According to a preferred embodiment, the temperature of the first gas and/or steam flow is controlled to be between 45°C and l50°C.

In a preferred embodiment, the temperatures of the intermediate gas and/or steam flow or flows are controlled to be between 150°C and 350°C.

According to a preferred embodiment, the temperature of the last gas and/or steam flow is controlled to be between 10°C and 100°C.

According to a preferred embodiment, the intermediate gas and/or steam flow or flows comprise steam, and the relative humidity of the intermediate gas and/or steam flow or flows is controlled.

According to a preferred embodiment, the generating of one or more intermediate gas and/or steam flows through the intermediate zone or zones comprises the generating of a saturated and/or superheated steam flow, such as to perform a sterilisation and/or pasteurisation of the particulate material.

According to a third aspect of the invention, an apparatus is provided for roasting particulate material, such as coffee or cacao beans, grains, malt, said apparatus comprising:

a transport system configured to transport a layer of particulate material through a treatment compartment comprising one or more zones, such that the particulate material passes consecutively through the zone or zones;

one or more fluid generating units configured for generating one or more gas and/or steam flows through the zone or zones;

wherein the zone or zones comprise a first zone and a second zone, and wherein the fluid generating unit or units comprise:

a first fluid generating unit configured for generating a first gas and/or steam flow through the first zone in a first direction that is substantially perpendicular to the layer of particulate material, and a second fluid generating unit configured for generating a second gas and/or steam flow through the second zone in a second direction opposite to the first direction;

said apparatus further comprising a control system configured to control the fluid generating unit or units, such that the layer of particulate material is preheated in the first zone and roasted in the second zone and optionally in the following zones.

The characteristics of the preferred embodiments described in connection with the first and second aspects of the invention may be combined with those of the third aspect of the invention. It should be noted that the zones defined in this third aspect of the invention correspond to the intermediate zones defined in the first two aspects of the invention.

According to a preferred embodiment, the treatment compartment of the apparatus has an even number of zones. According to an exemplary embodiment, the treatment compartment of the apparatus has at least two zones, preferably four zones, and more preferably six zones.

In a preferred embodiment, the control system is configured to use at least a portion of the second gas and/or steam flow that has passed through the second zone for generating at least a portion of the first gas and/or steam flow, and vice versa.

BRIEF DESCRIPTION OF THE FIGURES

This, and other, aspects of the present invention will be described hereinafter in greater detail with reference to the attached drawings illustrating a currently preferred embodiment of the invention. In the drawings, identical reference numerals correspond to identical or similar characteristics.

Figure 1 illustrates a schematic view of an exemplary embodiment of a continuous particulate material roasting apparatus according to the invention;

Figures 2, 3 and 4 schematically illustrate other exemplary embodiments of a continuous particulate material roasting apparatus according to the invention; and

Figure 5 illustrates a schematic view of a more detailed exemplary embodiment of a continuous particulate material roasting apparatus according to the invention.

DESCRIPTION OF THE EMBODIMENTS

Figure 1 illustrates a schematic view of an exemplary embodiment of a continuous particulate material roasting apparatus according to the present invention.

In the exemplary embodiment illustrated in Figure 1 , the continuous roasting apparatus comprises a treatment compartment 100, a transport system 200, a first fluid generating unit 310, two intermediate fluid generating units 320, 330, a last fluid generating unit 340, as well as a control system 400. The treatment compartment 100 is composed of a first zone Zl, two intermediate zones Zil, Zi2, and a last zone Zd. The transport system 200 is configured to transport a layer L of particulate material P through the treatment compartment 100, such that the particulate material P passes consecutively through the first zone Zl, the two intermediate zones Zil, Zi2, and the last zone Zd. The person skilled in the art will understand that the number and length of each zone may vary. Thus, each zone may have its own length, and the treatment compartment 100 may comprise more than two intermediate zones.

According to other embodiments, the first zone Zl and/or the last zone Zd may be absent from the treatment compartment 100, the latter being able to comprise solely of one or more intermediate zones Zil, Zi2, etc., such that the particulate material P passes consecutively through the intermediate zones Zil, Zi2, etc. Consequently, the first fluid generating unit 310 and/or the last fluid generating unit 340 may be absent from the roasting apparatus.

Thus, according to these embodiments, the control system 400 can be configured to control said intermediate fluid generating units 320, 330, etc., such that the layer L of particulate material P is preheated in the first intermediate zone Zil and roasted in the following intermediate zone or zones Zi2, etc. As a result, the first intermediate zone Zil fulfils the role of the first zone Zl, and in the absence of the last zone Zd, the layer L of particulate material P may be cooled outside the treatment compartment 100, for example in ambient air.

The transport system 200 comprises feeding means 210 configured to feed the particulate material P, without introducing air from the environment, such that the layer L has a thickness which comprises not more than 10 particles of particulate material, such as coffee or cacao beans, grains, malt, having a thickness which is smaller than 100mm, preferably not more than 3 particles, having a thickness which is smaller than 20mm, and more preferably not more than 2 particles, having a thickness which is smaller than 15mm.

In the exemplary embodiment illustrated in Figure 1, the transport system 200 comprises a conveyor belt 220 with a substantially flat surface that supports the layer L of particulate material P. The conveyor belt 220 passes through the first zone Zl, the two intermediate zones Zil, Zi2, and the last zone Zd. The transport system 200 is also configured to move the layer L of particulate material P at a substantially constant speed v, for example being between lmm/s and lm/s, through the first zone Zl, the two intermediate zones Zil, Zi2, and the last zone Zd.

In the exemplary embodiment illustrated in Figure 1, the first fluid generating unit 310 is configured for generating a first gas and/or steam flow FI through the first zone Zl, the two intermediate fluid generating units 320, 330 are configured for generating two intermediate gas and/or steam flows Fil, Fi2 through the intermediate zones Zil, Zi2, and the last fluid generating unit 340 is configured for generating a last gas and/or steam flow Fd through the last zone Zd. The conveyor belt 220 is configured to allow the first gas and/or steam flow Fl, the two intermediate gas and/or steam flows Fil, Fi2 and the last gas and/or steam flow Fd to pass through the layer L of particulate material P which it supports, preferably substantially perpendicular to the layer L of particulate material P. For example, the conveyor belt 220 may comprise apertures in the same way as a perforated belt, or may be made of porous material, thus allowing the flow of gas and/or steam to pass through.

The treatment compartment 100, the first, the two intermediate, as well as the last fluid generating units 310, 320, 330, 340 and the control system 400 form a substantially closed system, such that substantially no energy escapes from the substantially closed system. The control system 400 is configured to use at least a portion of the gas and/or steam flow that has passed through one of the zones Zl, Zil, Zi2, Zd for generating at least a portion of the gas and/or steam flow of another zone Zl, Zil, Zi2, Zd, preferably from another zone upstream of said zone.

In the exemplary embodiment illustrated in Figure 1, the first intermediate gas generating unit 310 is configured for generating a first intermediate gas flow Fil through the first intermediate zone Zil in a first direction Dil which is substantially perpendicular to the layer L of particulate material P. Furthermore, the second intermediate gas generating unit 320 is configured for generating the second intermediate gas flow Fi2 through the second intermediate zone Zi2 in a second direction Di2 opposite to the first direction Dil, and so on. This configuration allows optimal recovery and recirculation of gas and/or steam flows, because there are as many intermediate zones in which the flow circulates in one direction as there are intermediate zones in which the flow circulates in the opposite direction. Furthermore, in this way the layer L of particulate material P is subjected to an ascending flow for the same length of time as a descending flow, which guarantees a substantially homogeneous roasting, in the case where the zones have the same length. In other embodiments, the transport compartment 100 may comprise a multitude of intermediate zones, and alternate adjacent zones may be provided in which a gas and/or steam flow circulates in one direction, as well as adjacent zones in which a gas and/or steam flow circulates in the opposite direction.

The control system 400 is configured to control the temperature Tl and/or the composition and/or the speed of the first gas and/or steam flow Fl, the two intermediate gas and/or steam flows Fil, Fi2, and the last gas and/or steam flow Fd. The temperature Tl is controlled to be between 45 °C and l50°C, the temperatures Til, Ti2 are controlled to be between l50°C and 350°C, and the temperature Td is controlled to be between l0°C and l00°C. The relative humidity of the two intermediate gas and/or steam flows Fil, Fi2 is also controlled. Typically, the temperature Til of the first intermediate zone Zil is higher than the temperature Tl of the first zone Zl, and the temperature of an intermediate zone downstream of a given intermediate zone is greater than that of said zone. In addition, typically the temperature Td of the last zone Zd is lower than the temperature Tl of the first zone Zl.

Figure 2 schematically illustrates another exemplary embodiment of a continuous particulate material roasting apparatus according to the invention.

In the exemplary embodiment illustrated in Figure 2, the treatment compartment is composed of a first zone Zl, four intermediate zones Zil, Zi2, Zi3, Zi4, and a last zone Zd. The transport system 200 comprises two vertically positioned parallel plates, static or mobile, 221, 222, between which the layer L of particulate material P moves under the action of gravity or under the action of the movement of the two mobile plates. The two parallel plates 221, 222 are configured to allow the first gas and/or steam flow Fl of the first zone Zl, the four intermediate gas and/or steam flows Fil, Fi2, Fi3, Fi4 of the four intermediate zones Zil, Zi2, Zi3, Zi4, and the last gas and/or steam flow Fd of the last zone Zd to pass through. The gas and/or steam flows pass through the layer L of particulate material P in two opposite directions within two adjacent zones.

Figure 2 illustrates the possibility of using plates 221, 222, preferably parallel, forming part of the transport system 200. Flat or curved plates 221, 222 may be envisaged, describing straight or sinuous open lines such as meanders, or closed lines such as circles. These plates 221, 222 may lie in a horizontal plane or in a vertical plane, the second choice having been illustrated in Figure 2. Thus, under the action of gravity the particulate material P can undergo acceleration between the two plates 221, 222. It is possible to play around with zones of different lengths and with materials inducing a frictional force between the particulate material and the plates. A solution such as the production of zones downstream of the first zone Zl of ever increasing length makes it possible to maintain similar contact times between the particulate material P and the gas and/or steam flow within each zone. It is also possible to grip the particulate material P between two vertically oriented conveyor belts. The person skilled in the art understands that there may be a plurality of embodiments offering different geometries, orientations and materials for producing the plates 221, 222.

Figure 3 schematically illustrates a third exemplary embodiment of a continuous particulate material roasting apparatus according to the invention. In the exemplary embodiment illustrated in Figure 3, the treatment compartment 100 is composed of a first zone Zl, four intermediate zones Zil, Zi2, Zi3, Zi4, and a last zone Zd. The transport system 200 is composed of three distinct portions: a descending portion 220a, a horizontal portion 220b, and an ascending portion 220c. Again, the gas and/or steam flows pass through the layer L of particulate material P in two opposite directions within two adjacent zones. The difference from the exemplary embodiment of Figure 2 is found in the angle between the layer L of particulate material P and the different gas and/or steam flows. Indeed, while in the second intermediate zone Zi2 the intermediate gas and/or steam flow Fi2 passes through the layer L of particulate material P substantially perpendicularly, the other gas and/or steam flows FI, Fil, Fi3 , Fi4, Fd are oriented at an angle substantially not at right angles to the layer L of particulate material P. Thus, the area necessary for the installation of the apparatus can be reduced.

Figure 4 schematically illustrates a fourth exemplary embodiment of a continuous particulate material roasting apparatus according to the invention.

In the exemplary embodiment illustrated in Figure 4, the treatment compartment 100 is composed of a first zone Zl, eight intermediate zones Zil, Zi2, etc., Zi8, and a last zone Zd. The difference from the exemplary embodiment of Figure 3 is found in the succession of distinct portions that make up the transport system 200. Indeed, the latter comprises a first horizontal zone Zl and a first horizontal intermediate zone Zil 220a, a second ascending intermediate zone Zi2 220b, three consecutive horizontal intermediate zones Zi3, Zi4, Zi5 220c, two descending intermediate zones Zi6, Zi7 220d, and finally a last horizontal intermediate zone Zi8 and a last horizontal zone Zd 220e. The ascending portion 220b can be embodied for example by a conveyor screw. The upper portion 220c makes it possible to obtain a higher concentration of steam, while the lower portions 220a, 220e contain a higher concentration of gas. The advantage of such an embodiment is that this apparatus can be used under conditions of saturated and/or superheated steam. Since the steam is lighter than the gas, the particulate material is thus transported from the lower portion 220a to the upper portion 220c immersed in an atmosphere of saturated and/or superheated steam, in which it is treated, sterilised and/or pasteurised, and is then transported from the upper portion 220c to the lower portion 220e.

Figure 5 illustrates a schematic view of a more detailed exemplary embodiment of a continuous particulate material roasting apparatus according to the invention. All the operating characteristics described in the text relating to Figure 1 remain valid for the embodiment shown in Figure 5. In the exemplary embodiment illustrated in Figure 5, the treatment compartment 1100 is composed of a first zone Zl, six intermediate zones Zil, Zi2, etc., Zi6, and a last zone Zd. The transport system 1200 comprises feeding means 1210 configured to feed the particulate material P, without the introduction of ambient air, and a conveyor belt 1220 with a substantially flat surface which supports the layer L of particulate material P. The conveyor belt 1220 passes through the first zone Zl, the six intermediate zones Zil, Zi2, etc., Zi6 and the last zone Zd. The feeding means 1210 may consist of an airtight and unidirectional entry chamber 1211 for the particulate material, so as to ensure that the treatment compartment 1100, the first, the six intermediate, and the last fluid generating unit 1310, 1320, 1330, etc., 1380 and the control system 1400 form a substantially closed system, thereby avoiding the escape of energy from the substantially closed system.

The treatment compartment 1100 is formed of a box, for example a metal enclosure, comprising a plurality of wall sections: a first wall section 1110 surrounding the first zone Zl, six intermediate wall sections 1120, 1130, etc., 1170 surrounding the six intermediate zones Zil, Zi2, etc., Zi6, and a last wall section 1180 surrounding the last zone Zd. Between two consecutive wall sections there may be a thermal compensator 1115 to compensate for the thermal expansion of the different materials used to design the box. Within each wall section, a plenum 1125, 1135 can be above and/or below the conveyor belt 1220, which is partially delimited for example by a perforated plate and the surface of said wall section. Such a device serves to increase the pressure as well as to homogenise the speed of the gas and/or steam flows that pass through the conveyor belt 1220. The presence preferably of two plena 1125, 1135 in each wall section, on either side of the conveyor belt 1220, makes it possible to provide a symmetrical modification of the direction of the gas, for example air, and/or steam flow within said wall section, ascending or descending. At the end of the treatment compartment 1100 there can be a device 1230 for discharging the roasted and cooled particulate material P.

A first fluid generating unit 1310, six intermediate fluid generating units 1320, 1330, etc., 1370, and a last fluid generating unit 1380 are also schematically shown in Figure 5. Since the operation of each fluid generating unit is similar, its description may be concentrated on the first unit 1310. This may comprise a separator 1311 of husks, from coffee or cacao beans for example, which are carried by the gas and/or steam flow and which fall into the fluid generating unit 1310. These husks are extracted from the flow by the separator 1311, which could be a cyclone, for example. The fluid generating unit 1310 also comprises a fan 1312 for regulating the speed of the air in the first zone Zl, and a heat exchanger 1313 for regulating the temperature of the air and/or the steam. The first fluid generating unit 1310 also includes a plurality of valves for controlling access of air and/or steam to the various circuits that make up each fluid generating unit. In addition to the air Ai and steam Si intake circuits, and air Ao and steam So outlet circuits, a water circuit is schematically shown in Figure 5, the input Wi being supplied for example by demineralised water, and the output Wo allowing evacuation of the dirty water containing waste from the treatment compartment 1100. Just downstream of the input of the circuit Wi is a vacuum pump 1315 allowing the circulation of water in the circuit. This water circuit also regulates the moisture content in the air and/or steam.

The value of measurements such as temperature, speed, composition and relative humidity of the air and/or steam flow is regulated by a control system (not shown in Figure 5). A series of indicating sensors (PI) and transmitter sensors (PT, TT, FT) measuring temperature, pressure and flow are present on the various air, steam and water circuits. In addition, relative humidity sensors (RH) are present on the air circuit.

Finally, the fluid generating unit 1310 includes a Wheatstone bridge for selecting the direction of the air and/or steam flow, ascending or descending. In this way, it can be ensured that the air and/or steam flows circulating in two adjacent zones of the treatment compartment 1100 circulate in opposite directions.

In the particular case of coffee beans, the temperature of the first zone Z1 is preferably between 45°C and 150°C, and its length preferably between 0.5m and 10m. The temperature Til of the first intermediate zone Zil is preferably between 55°C and 350°C, and its length preferably between 0.5m and 10m. The temperature Ti2 of the second intermediate zone Zi2 is preferably between 100°C and 350°C, and its length preferably between 0.5m and 10m. The temperature Ti3 of the third intermediate zone Zi3 is preferably between 150°C and 350°C, and its length preferably between 0.5m and 10m. The temperature Ti4 of the fourth intermediate zone Zi4 is preferably between 150°C and 350°C, and its length preferably between 0.5m and 10m. The temperature Ti5 of the fifth intermediate zone Zi5 is preferably between 150°C and 350°C, and its length preferably between 0.5m and 10m. The temperature Ti6 of the sixth intermediate zone Zi6 is preferably between 150°C and 350°C, and its length preferably between 0.5m and 10m. Finally, the temperature of the last zone Zd is preferably between 10°C and 100°C, and its length preferably between 0.5m and 10m.