US-12616234-B2 - Method for drying a smoke filter unit

US12616234B2US 12616234 B2US12616234 B2US 12616234B2US-12616234-B2

Abstract

The invention concerns a method for drying at least one cell of the electrostatic precipitator of a smoke treating unit in a system of a coffee beans roasting apparatus and a smoke treating unit, said method comprising the step of passing hot air through said cell, while said cell is positioned inside the electrostatic precipitator and while said cell is switched off.

Inventors

Joel Morend
RISTE PINDJUROV
Flavien Florent Dubief
Daniel Roland Manser

Assignees

SOCIETE DES PRODUITS NESTLE S.A.

Dates

Publication Date: 20260505
Application Date: 20201214
Priority Date: 20191213

Claims (8)

1 . A method to dry at least one wet removable cell of an electrostatic precipitation smoke filter of a smoke treating unit of a roasting system, the system comprising: a roasting apparatus, a smoke treating unit configured to treat the smoke produced by the roasting apparatus, the smoke treating unit comprising the electrostatic precipitation smoke filter, the electrostatic precipitation smoke filter comprising the at least one wet removable cell, the at least one wet removable cell comprising ionization wires, collecting electrodes and repelling electrodes, the wires and electrodes being supplied with an electrical power, wherein the method comprises at least the step of passing hot air through the at least wet removable cell, while the at least one wet removable cell is positioned inside the electrostatic precipitator and while the at least one wet removable cell is switched off, and wherein the hot air is generated by the roasting apparatus while the roasting chamber of the apparatus is empty, in particular void of coffee beans.
2 . The method according to claim 1 wherein, while passing the hot air through the at least one cell of the electrostatic precipitator, the method comprises the steps of: S1—keeping the at least one cell of the electrostatic precipitator switched off during one first pre-determined period, then S2—at the end of the first pre-determined period, electrically switching on the at least one wet removable cell, and if short-circuit is detected during a second pre-determined period, implementing steps S1 and S2 again, if no short-circuit is detected during the second pre-determined period, finishing the operation of passing cooling air through the cell.
3 . The method according to claim 2 , wherein: if no short-circuit is detected during step S2, an intermediate checking step S3 is implemented before finishing the operation of passing the cooling air through the at least one wet removable cell, wherein during the intermediate checking step S3 the hot air is passed through the at least one wet removable cell of the electrostatic precipitator while the at least one wet removable cell is switched on, and if short-circuit is detected during step S3, steps S1 and S2 are implemented again.
4 . The method according to claim 2 , wherein the step of finishing the operation of passing hot air through the at least one wet removable cell comprises the step of passing cooling air through the at least one wet removable cell.
5 . The method according to claim 1 , wherein the electrostatic precipitator comprises several cells and, during step S2, each of the at least one wet removable cell is successively switched on in order to detect short circuit on the at least one wet removable cell.
6 . The method according to claim 1 wherein the smoke treating unit comprises an active carbon filter and/or at least one metallic mesh filter.
7 . The method according to claim 1 wherein: the smoke treating unit comprises an active carbon filter, and the hot air is passed through the at least one wet removable cell while keeping the temperature of the active carbon filter at most 65° C.
8 . A computer program comprising instructions which, when executed by a computer, processor or control unit, cause the computer, processor or control unit to perform the method to dry at least one wet removable cell of an electrostatic precipitation smoke filter of a smoke treating unit of a roasting system, the system comprising: a roasting apparatus, a smoke treating unit configured to treat the smoke produced by the roasting apparatus, the smoke treating unit comprising the electrostatic precipitation smoke filter, the electrostatic precipitation smoke filter comprising the at least one wet removable cell, the at least one removable cell comprising ionization wires, collecting electrodes and repelling electrodes, the wires and electrodes being supplied with an electrical power, wherein the method comprises at least the step of passing hot air through the at least one wet removable cell, while the at least one wet removable cell is positioned inside the electrostatic precipitator and while the at least one wet removable cell is switched off, and wherein the hot air is generated by the roasting apparatus while the roasting chamber of the roasting apparatus is empty, in particular void of coffee beans.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a National Stage of International Application No. PCT/EP2020/085891, filed on Dec. 14, 2020, which claims priority to European Patent Application No. 19216321.0, filed on Dec. 13, 2019, the entire contents of which are being incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to apparatuses for roasting coffee beans in a safe environment. BACKGROUND OF THE INVENTION The roasting of coffee beans is a well-known process. The main steps consists in heating the beans to a desired roasting level and then cooling or quenching the heated beans to stop the roasting. During heating, smoke is emitted. This smoke contains safe and desired components all together, in particular the usual roasted coffee aroma, but also undesired less safe volatile organic compounds (VOC) VOC such as pyridine, 2-furane methanol, caffeine furfural, formaldehyde, acetaldehyde, . . . and particulate matter (PM25, PM10), . . . . When roasting is implemented in manufacturing places producing important quantities of roasted beans, generally all the conditions for catching unsafe components are supplied. But, there is a recent trend to implement small batch roasting with small roasters in shops, restaurants and coffees where customers are able to consume coffee brewed from freshly roasted beans. The roaster does not only provide freshness and theater advantages, but also dispenses the pleasant roasted coffee aroma inside the shop or coffee. Yet, as mentioned above, harmful components are emitted too. When the roaster is used in a closed environment like a shop, coffee or restaurant, the emission of some components can become harmful depending on the size of the room, the ventilation of the room, . . . . For people working several hours in the room, smelling the smokes of the roaster can lead to a health problem. As a result, in such an environment, it is recommended to stop the emission of smoke from the roaster to avoid any healthy issue for people present in the shop. The existing solutions consist in destroying contaminants, such as an afterburner enabling thermal oxidation of contaminants or a catalytic afterburner or retaining contaminants inside the apparatus like mechanical filters (metallic sieves or paper filter), an active carbon filter or an electrostatic precipitator or combination thereof. An electrostatic precipitator catches some PM. The advantages of an electrostatic precipitator is its low cost of purchase and use, the absence of noise or heat generated during its use. Since, the electrostatic precipitator traps the contaminants that remain attached to the electrified cell of the electrostatic precipitator, the apparatus must be regularly cleaned. The cleaning operation consists in removing the cells of the electrostatic precipitator from the filter device and washing them with water and optionally with a detergent. Then the cells need to dry before being reinstalled inside the filter unit otherwise water drop creates breakdown in the filter device when it is operated. Since even very small drops of water create malfunction of the cells, it is essential that the cells are well dried before being re-installed. For this reason, drying of the cells requires a sufficient time. Generally a period of 12 hours is necessary. The operator can wash the cells at the end of the day and get them dried the next morning. This period of drying is not a problem when the roasting apparatus and its associated filter are used once in a day or occasionally, but with the recent trend to use small roasters in shops, restaurants and coffees, roasting operations can happen frequently during the opening hours and the need for cleaning the smoke filter device can happen urgently during the opening hours. In that case, the length of the cleaning becomes incompatible with the high rate of use of the roaster and the filter device. An object of the invention is to address the problem of enabling the cleaning of the unit treating the smoke resulting from coffee beans roasting and comprising an electrostatic precipitator in a short period of time. SUMMARY OF THE INVENTION In a first aspect of the invention, there is provided a method to dry at least one wet removable cell of an electrostatic precipitation smoke filter of a smoke treating unit (3) in a roasting system, said system comprising: a roasting apparatus, anda smoke treating unit configured to treat the smoke produced by the roasting apparatus, said smoke treating unit comprising said electrostatic precipitation smoke filter,said electrostatic precipitation smoke filter comprising said least one removable cell, and said cell comprising ionization wires, collecting electrodes and repelling electrodes, andsaid cell being supplied with electrical power, wherein the method comprises at least the step of passing hot air through said wet removable cell, while said cell is positioned inside the electr