Coffee roaster oven chamber

A coffee roaster oven chamber wherein coffee beans are heated and intermixed in a fluidized bed is fabricated as a unitary structure from a transparent material that allows incandescent coils to radiantly heat coffee beans while they are concurrently heated by air heated by the same coils. In a preferred embodiment the oven chamber is fabricated from glass as a single piece structure which may be removed from the coffee roaster for adding or removing coffee beans and cleaning.

BACKGROUND OF THE INVENTION 
The shortcomings of the prior coffee roasting systems utilizing a fluidized 
bed created by a flared chamber have been eliminated by the use of a 
rotating fluidized bed as described in U.S. Pat. No. 4,494,314 for "Coffee 
Roaster" and U.S. Pat. No. 5,359,788 for "Coffee Roaster" issued to Harold 
Gell on Jan. 22, 1985 and Nov. 1, 1994 respectively. With the advent of 
rotating fluidized bed applications to coffee roaster technology and 
transparent upper oven chambers which allow operators to monitor the 
roasting process, the problems involving the actual roasting technique 
have been solved. However, the different thermal expansion characteristics 
of the glass upper oven chamber and metal lower oven chamber results in a 
high failure rate of the glass chamber section and problems remain with 
respect to removing roasted coffee beans from the oven chamber, cleaning 
the oven chamber and manufacturing the oven chamber. 
OBJECTIVES OF THE INVENTION 
To avoid the shortcomings in the prior art coffee roasters, it is a primary 
objective of this invention to provide a transparent oven chamber 
fabricated as a unitary structure with openings in its lower section for 
admitting air to create a rotating fluidized bed of coffee beans within 
the oven chamber and an open top to allow roasting by-product gases and 
chaff to escape and to add and remove coffee beans. 
It is a further objective of the present invention to provide an oven 
chamber as described above that is created from borosilicate glass. 
Another objective of the present invention to provide an oven chamber as 
described above that is removable and replaceable by the operator to 
facilitate adding and removing coffee beans and cleaning. 
A still further objective is to provide an oven chamber fabricated from a 
transparent material which will allow an incandescent heater to radiantly 
heat a coffee bean charge which is concurrently being heated with air 
previously heated by the incandescent heater. 
The foregoing and other objectives of the invention will become apparent in 
light of the drawings, specification and claims contained herein. 
SUMMARY OF THE INVENTION 
A transparent oven chamber is fabricated from a high temperature glass, 
such as borosilicate glass, as a one piece body through which coffee beans 
may be heated by radiation from an incandescent heater. The oven chamber 
includes openings in the lower section for admitting heated air to assist 
in heating the coffee beans and to create a rotating fluidized bed of 
coffee beans within the oven chamber. The section of the oven chamber 
including the openings is shaped and dimensioned to fit within a coffee 
roaster plenum and thereby allow user removal and replacement of the oven 
chamber for facilitating removal of roasted coffee beans and for cleaning.

DESCRIPTION OF THE INVENTION 
FIG. 1 is a front view of a coffee roaster incorporating the unitary 
transparent oven chamber of the present invention. The coffee roaster is 
comprised of a roaster housing 10 which includes heating and heater 
control means and an oven chamber receiving plenum, 11 of FIG. 2. The 
unitary oven chamber 12 is shown installed in a coffee roaster with the 
lower part of the transparent cylinder from which the oven chamber is 
formed seated within the roaster's plenum 11 and the upper or viewing 
chimney portion extending above the roaster housing. A chaff trap 13 fits 
over the access opening of the oven chamber. The chaff trap is removed 
when the oven chamber is being charged with coffee beans or when roasted 
beans are removed. 
To charge the oven chamber of the preferred embodiment, the chaff trap 13 
is removed and green coffee beans are added through the top, 14, of the 
oven chamber. For this step in the coffee roasting procedure using the 
preferred form of the invention, the oven chamber 12 may be installed in a 
coffee roaster or removed therefrom to be seated within the plenum 11 of 
the roaster before the actual roasting commences. In all instances, the 
chaff trap is replaced on the top of the oven chamber before the roaster 
is turned on. 
An incandescent heater 19 heats coffee beans through the transparent body 
of the oven chamber and air passing through the plenum, causing coffee 
beans within the oven chamber to be roasted by the heated air and 
radiation from the incandescent heater. 
When roasted coffee beans have been cooled, the chaff trap is removed and 
the oven chamber 12 lifted from the roaster, in any order, after which the 
roasted beans are poured from the oven chamber. 
In an alternate embodiment, the removable, unitary oven chamber 12 may be 
secured within the roaster and roasted coffee beans removed therefrom by 
lifting and tilting the roaster. In this embodiment the oven chamber is 
removed for cleaning by placing it in a dishwasher or using manual means. 
The oven chamber preferably is a one piece structure of metal, ceramic, 
glass or other suitable material that will withstand the heat of roasting 
coffee. A glass structure is preferred for ease of fabrication, but 
regardless of the material, the key feature of the oven chamber is that it 
is removable to facilitate cleaning and removing roasted coffee beans. 
In the preferred embodiment, the oven chamber 12 is a borosilicate glass 
cylinder, open at the top 14 and closed at the bottom as illustrated by 
FIG. 3. A plurality of openings 15 are located in the lower section of the 
cylinder. The openings may be in the form of louvers or simple slots cut 
through the cylinder forming passages which lie at an angle other than 180 
or 360 degrees to the ray from the slot to the central axis of the 
cylinder. Thus when air is forced from the plenum of the roaster into the 
oven chamber, it flows along a path which is tangent to the oven chamber 
wall, causing the air to rotate about the vertical axis of the oven 
chamber. 
A dome 16 is located in the center of the bottom of the oven chamber. It 
urges coffee beans at the center to migrate towards the wall where they 
come under the influence of the tangent flow of air from the plenum which 
causes the creation of a rotating fluidized bed. 
A handle 17 may be provided to facilitate handling the oven chamber when it 
is hot. The handle may be an integral part of the oven chamber or an 
attachment. 
An increased diameter upper oven chamber section or a flange or bead 18 may 
be provided to cooperate with the top of the coffee roaster plenum 11 to 
create an air dam to prevent air from escaping from the plenum along the 
outer wall of the oven chamber. If a bead or flange is used to create the 
air dam, it may be used as a means to temporarily secure the oven chamber 
to the roaster. 
While preferred embodiments of this invention have been illustrated and 
described, variations and modifications may be apparent to those skilled 
in the art. Therefore, I do not wish to be limited thereto and ask that 
the scope and breadth of this invention be determined from the claims 
which follow rather than the above description.