COFFEE BEANS ROASTING APPARATUS

Abstract

The invention concerns an apparatus (10) for roasting coffee beans comprising : - a housing (7), - a roasting chamber (1) presenting a bottom opening (11), said chamber extending along a chamber axis, preferably essentially vertical, from said bottom opening, - an air driver configured to drive a flow of air inside the roasting chamber through the bottom opening of said chamber, - an electrical heater (3) configured to heat air driven inside the roasting chamber, wherein : - the air driver (2) and the electrical heater (3) are positioned aside the area vertically below the bottom opening (11) of the roasting chamber.

Claims

1. Apparatus for roasting coffee beans comprising: a housing, a roasting chamber presenting a bottom opening, said chamber extending along a chamber axis, from said bottom opening, and said bottom opening comprising a grid to retain coffee beans inside the chamber, an air driver configured to drive a flow of air inside the roasting chamber from the bottom of said chamber, an electrical heater configured to heat air driven inside the roasting chamber, wherein the air driver and the electrical heater are positioned aside the area vertically below the bottom opening of the roasting chamber, the air driver is oriented inside the housing in order to produce an initial flow of air flowing along an initial air axis, said initial air axis being different from the roasting chamber axis, the apparatus comprises a guiding member configured to convert the initial flow of air produced by the air driver in an upwardly flow of air oriented along the axis of the roasting chamber and to the bottom opening of the roasting chamber, said guiding member comprises at least one vertically oriented cylindrical duct, said duct comprising a lateral air inlet designed to introduce the flow of air, preferably tangentially, inside the duct, said vertically oriented cylindrical duct is internally shaped to convert the flow of air introduced through the lateral air inlet in an upwardly swirling flow of air, and the vertically oriented duct extends downwards the lateral air inlet and the bottom end of said duct is opened or openable.

2. Apparatus according to claim 1, wherein the guiding member is configured to generate a balanced flow of air at the bottom opening of the roasting chamber.

3. Apparatus according to claim 1, wherein the initial air axis forms an angle comprised between 90 and 180° with the upwardly rising roasting chamber axis.

4. Apparatus according to claim 1, wherein the air driver is oriented inside the housing in order to produce an initial flow of air oriented horizontally and at a vertical level situated below the bottom opening of the roasting chamber.

5. Apparatus according to claim 1, wherein at least one temperature probe is positioned in the at least one guiding member and downstream the heater.

6. Apparatus according to claim 1, wherein at least one temperature probe is positioned aside the area vertically below the bottom opening of the roasting chamber.

7. Apparatus according to claim 1, wherein at least one temperature probe is positioned at the downstream side of the vertically oriented cylindrical duct.

8. Apparatus according to claim 1, wherein at least one temperature probe is positioned inside the chamber.

9. Apparatus according to claim 1, wherein the at least one part of the guiding member is removable from the housing.

10. Apparatus according to claim 1, wherein at least a part of the walls of the guiding member is covered with a second wall.

11. Apparatus according to claim 1, wherein the roasting chamber is removable from the housing.

12. Apparatus according to claim 1, wherein said apparatus comprises more than one air driver, each air driver being connected to one common manifold configured to guide air flows from said more than one driver into an upwardly direction along the roasting chamber axis at the bottom opening of the roasting chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Specific embodiments of the invention are now described further, by way of example, with reference to the following drawings in which:

[0064] FIG. 1 is a schematic view of a roasting apparatus according the state of the art,

[0065] FIG. 2 is a perspective view of the roasting unit of a roasting apparatus according the invention,

[0066] FIG. 3 is a cross section view of the roasting unit of FIG. 2 vertical along the vertical plane extending through the horizontal duct 5 and the chamber 1,

[0067] FIG. 4 is a cross section view of the roasting unit of FIG. 2 along the horizontal plane extending through the horizontal duct 5,

[0068] FIG. 5 illustrates schematically different configurations for a roasting apparatus according to the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0069] FIG. 1 shows an illustrative side view part of a roasting apparatus 10 according to the prior art. Functionally, the roasting apparatus 10 is operable to roast coffee beans hold in a chamber 1 by means of a flow of hot air introduced inside this chamber. The apparatus comprises a housing 7 and a roasting unit.

[0070] The roasting unit is operable to receive and roast coffee beans.

[0071] The roasting unit typically comprises at a second level of the roasting apparatus 10: a chamber 1, an air flow driver 2, a heater 3, which are sequentially described.

[0072] The chamber 1 is configured to receive and hold the coffee beans introduced by the operator. In the preferred embodiment, the chamber 1 is removable from the housing 4. The chamber can be put aside the roasting apparatus: [0073] for the introduction or the removal of coffee beans, or [0074] for cleaning and maintenance of the chamber once it is removed, or [0075] for cleaning of the vertical housing part behind the chamber.

[0076] In one embodiment, this chamber can be non-removable, in particular when the introduction and and removal of the coffee beans can be done automatically, for example as described in WO2012059484 or if the chamber is easily accessible for cleaning.

[0077] The bottom opening 11 of the chamber is configured to enable air to pass through, specifically it can comprise a perforated plate on which the beans can lie and through which air can flow upwardly. This perforated blade can comprise perforation designed to provide the air flow with a specific flow pattern inside the chamber. The chamber 1 comprises a handle in order to enable the user to remove the chamber from the housing and hold it outside the housing.

[0078] A chaff collector 13 is in flow communication with the chamber 1 to receive chaffs that progressively separate from the beans and due to their light density are blown off to the chaff collector.

[0079] The air flow driver 2 is operable to generate a flow of air (dotted lines arrows) in direction of the bottom of the chamber. The generated flow is configured to heat the beans and to agitate and lift the beans. As a result the beans are homogenously heated. Specifically, the air flow driver can be a fan powered by a motor. Air inlets 42 can be provided inside the housing in order to feed air inside the housing, the air flow driver blowing this air upwardly though a passage 8 in direction of the chamber 1 as illustrated by dotted lines arrows.

[0080] The heater 3 is operable to heat the flow of air generated by the air flow driver 2. The heater is an electrical resistance positioned between the fan 2 and the bottom opening 11 of the chamber with the result that the flow of air is heated before it enters the chamber 1 to heat and to lift the beans. The heater 3 is positioned just below an air outlet hole 41 in the housing fitting with the bottom opening 11 of the chamber.

[0081] The heater 3 is operable to apply a roasting profile to the beans, this roasting profile being defined as a curve of temperature against time. A temperature probe 6 is positioned upstream the electrical heater to measure the temperature of the hot air flow entering the chamber.

[0082] When the chamber is mounted to the housing, the bottom 11 of the chamber is connected through an air outlet hole 71 to the top end of the air passage 8. The top opening 12 of the chamber is connected to a smoke and particulates evacuation device (not illustrated).

[0083] As obvious from the relative position of the chamber, the heater and the air driver, small particles introduced inside the chamber or generated during the roasting operation can fall through the bottom opening 11 and the outlet 41 on the temperature probe 6, the electrical heater 3 and on the air driver 2. When the coffee beans are roasted to a high level, drops of coffee oil can fall too on the heater and the air driver.

[0084] Due to the heat in this area of the apparatus, these particles and drops easily stick to these devices and with time creates a greasy, sticky layer of burnt material. The impacts are: [0085] on the air driver: dirty aspect, reduced efficiency because change of the weight, loss of performance due to cross section reduction, vibrations, noise with dust from ambient air sticking to the fan, [0086] on the electrical heater: dirty coating on heating element (which can be resistive wire, infrared, ...) generating poor heat transfer coefficient and non-desired odours of burning particles, for example during pre-heating of the roaster, reduced airflow passages decreasing efficiency of heat transfer, [0087] on the temperature probe that becomes less and less reliable and that will drift in measured value and reactivity after some time.

[0088] During cleaning operation, water droplets ingress can also create short circuits in heater and fan with a risk of short circuit, electric shock, device damage or fire.

[0089] If as illustrated the chamber 1 is removable from the housing 7, a tiny access to the upper part of the heating unit is possible but cleaning cannot be correctly and completely done. In some roasting apparatus, the chamber is even not removable.

[0090] FIG. 2 is a perspective view of the roasting unit of a roasting apparatus according the invention. The chassis 9 supports the roasting chamber 1 and a chaff collector 13. Below the chamber 1, a horizontal duct 5 contains the air driver and the electrical heater as illustrated in the vertical cross section view of the roasting unit in FIG. 3.

[0091] The air driver 2 is oriented in order to produce an initial flow of air (dotted lines) flowing along an initial air axis XX', that is horizontal and different from the roasting chamber axis YY' that is vertical. In this configuration the air driver 2 and the electrical heater 3 are positioned aside the area 110 vertically below the bottom opening 11 of the roasting chamber. Accordingly, when particles fall from the bottom opening 11, they do not set on the heater 3 or the air driver 2.

[0092] The apparatus comprises a guiding means or junction device 4 configured to convert the horizontal initial flow of air produced by the air driver 2 in an upwardly flow of air oriented along the axis YY' of the roasting chamber and to the bottom opening 11 of the roasting chamber.

[0093] The junction device 4 comprises a vertically oriented cylindrical duct 41. This duct 41 comprises a lateral air inlet 411 designed to introduce the horizontal flow of air inside the duct. Preferably the horizontal flow of air is introduced tangentially inside the cylindrical duct as illustrated in FIG. 4. This configuration facilitates the conversion of the horizontal flow of air in an upwardly swirling flow or air. This swirling effect can be improved by the design of a concavity 412 facing the air inlet 411 and guiding the air in an upwardly ascending movement. As a result, the global direction of the air flow is changed from horizontal to vertical (thick dotted line in FIG. 3), but the local shape of the air flow can be a swirl as illustrated by small line in FIG. 3.

[0094] Alternatively, in a simpler design, the guiding device can be conduit with a 90° elbow.

[0095] The vertically oriented duct 41 extends downwards the lateral air inlet 411 down to a bottom end 413. This bottom end enables the collection of particles falling from the bottom opening of the chamber. Preferably, this bottom end 413 is openable so that the operator can remove particles during cleaning operation. In an alternative design, the bottom end 413 can be opened and a collector plate can be positioned below to receive particles.

[0096] At least one temperature probe 6 is positioned in the horizontal duct 5 downstream the heater. Again, this position of the probe prevents deposit of dirtiness on its surface which would impact the correct measure of temperature and a correct rosting of beans in the chamber.

[0097] In this configuration, the chamber 1 is removable from the chassis which enables the operator to access easily to the top part of the junction device for cleaning.

[0098] Preferably, a part of the guiding device such as the junction device 4 can be made removable from the chassis for an easier cleaning outside the apparatus. Since this part does not hold the heater 3 and the air driver 2, it does not comprise any electrical connection and removal by simple mechanical disconnection can be implemented.

[0099] In the illustrated embodiment a part of the walls of the guiding device such as the walls of the junction device 4 are covered with a second wall 415 which reduces heat loss.

[0100] FIG. 5 illustrates schematically other embodiments of the roasting apparatus with different positions and orientations of the air driver 2 and the heater 3 relatively to the roasting chamber 1.

[0101] In all cases, the air driver 2 and the electrical heater 3 are positioned aside the area 110 vertically below the bottom opening 11 of the roasting chamber.

[0102] In each case, the air driver 2 is oriented inside the housing in order to produce an initial flow of air flowing along an initial air axis XX' that is different from the roasting chamber axis YY'. The chamber is configured to create a fluidic bed of hot air to roast the beans and as such extends essentially vertically from the bottom opening 11. The roasting chamber axis YY' is essential vertical and the initial air axis XX' differ by their positions and optionally by their angles to the vertical.

[0103] In case A, the initial air axis XX' is vertical and oriented upwardly but it is positioned horizontally aside from the area 110. A duct is designed to guide air from the upward vertical direction at the air driver to the bottom opening of the chamber.

[0104] In case B, similarly to the above case A, the initial air axis XX' is vertical and oriented upwardly but it is positioned horizontally aside from the area 110. The heater can comprise several channels acting as a guiding device. By orienting the heater along an axis of about 30° with vertical in direction of the bottom opening, upwardly vertical air flow from the air driver 2 is heated and guided by the heater 3 in direction of the bottom opening 11. Baffles 414 between the air driver 2 and the heater 3 can serve as guiding device too. Other baffles, walls or chicanes can be present between the heater 3 and the bottom opening 11 and serve as a guiding device to the bottom opening 11.

[0105] In an alternative to case B, in case C, the initial air axis XX' defines an angle of about 30° with the upwardly rising roasting chamber axis YY'. The heater 3 is positioned on said axis XX' too. By orienting the air driver 2 and the heater 3 along an axis of about 30° with vertical in direction of the bottom opening, the air driver and the heater can still be positioned aside the area 110 below the bottom opening 11. Baffles, walls or chicanes between the air driver, the heater and the bottom opening can serve as guiding device.

[0106] In case D, the initial air axis XX' is horizontal and defines an angle of 90° with the upwardly rising roasting chamber axis YY'. This case corresponds to the preferred embodiment illustrated in FIGS. 2 to 4. This position of the air driver and the heater provides the advantage of designing a compact roasting apparatus, the height being reduced compared to the configurations of cases A to C.

[0107] Case E provides a compact configuration too: the initial air axis XX' is vertical and oriented downwardly that is defines an angle of 180° with the upwardly rising roasting chamber axis YY'. A U-shaped duct converts the air flow from the direction along the initial air axis at the air driver into the upwardly direction along the roasting chamber axis at the bottom opening of the roasting chamber.

[0108] This configuration enables a good mixing of hot air before it contacts the temperature probe. As a result the risk of having a gradient of temperature across the section of the guiding device at the position of the probe 6 is reduced, the measure of temperature is more accurate and the control of the heater to apply a roasting profile in the chamber is more efficient.

[0109] Although the invention has been described with reference to the above illustrated embodiments, it will be appreciated that the invention as claimed is not limited in any way by these illustrated embodiments.

[0110] Variations and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred in this specification.

[0111] As used in this specification, the words “comprises”, “comprising”, and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean “including, but not limited to”.

List of References in the Drawings

[0112] roasting chamber 1 [0113] bottom opening 11 [0114] area below bottom opening 110 [0115] top opening 12 [0116] air driver 2 [0117] heater 3 [0118] junction device 4 [0119] duct 41 [0120] inlet 411 [0121] concavity 412 [0122] bottom end 413 [0123] baffle 414 [0124] second wall 415 [0125] duct 5 [0126] temperature probe 6 [0127] housing 7 [0128] air passage 8 [0129] chassis 9 [0130] chaff collector 13