IMPROVEMENTS IN DRYING AND ROASTING MALT AND OTHER SUBSTANCES AND IN APPARATUS THEREFOR
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Charles Denton Abel at the Office
of the Commissioners of Patents on the 18th December 1882. Communicated
to him from Abroad by D Ludwig Mautner, Ritter von Markhof of Vienna in
the Austrian Empire.
CHARLES DENTON ABEL of N° 28 Southampton Buildings Chancery Lane in
the County of Middlesex. "IMPROVEMENTS IN DRYING AND ROASTING MALT AND
OTHER SUBSTANCES AND IN APPARATUS THEREFOR" [Communicated to him from
Abroad by Dr Ludwig Mautner, Ritter von Markhof of Vienna in the Austrian
Empire]
All processes and apparatus employed hitherto for drying malt have the great
disadvantage of not furnishing a homogenous material. The present improved
process permits of continuous working which can be regulated in all stages, so that
a perfectly uniform product is obtained; it consists in the employment in place of
the hurdles used heretofore of slowly rotating drums of perforated metal or wire
gauze, through which the heated air is driven by a fan.
The said drying drums are arranged in a building having three floors, one above
the other. The drums are constructed of woven or plaited wire or of perforated
sheet metal, which is stiffened by external ribs of half round iron. The openings
or meshes of the drums should be as large as possible consistent with retaining the
grain in the drum. The drums rest with trunnions attached to their solid end
surfaces in bearings which are by preference made to work dry, or if otherwise,
they are placed in a partition wall and are lubricated from chambers external to
the rooms containing the drying drums. The drums are driven by means of shafts
passing through the said partition wall, the openings in which are closed, as.com-
pletely as possible so that no smell of lubricating oil &c can pass into the drying
rooms. The doors and windows of the rooms are also closed as completely as
possible so that air can only enter them through the conduit pipes for the
heated air
'
The drying process is divided according to the present invention into three
parts. In the drum on the uppermost floor, the grain is rendered air dry, in the
drum below this, into which the grain then passes, it receives a preparatory

page_text: warming, and only in the lowest drum is the actual drying process effected, and if
required, also the roasting. The green malt is charged into the top drum from. an
upper chamber which is used as an air drying room. When it has become air dry
the drum is emptied and the malt descends through a shoot into the second drum
and thence through another shoot into the bottom drum. The finished product
passes through a shoot into a chamber below, where it may be charged at once into
trucks, transporting worms, or other transporting apparatus.
"
The temperature of the entering air must be regulated according to the processes
to which the malt is successively subjected and according to the product desired to
be obtained; thus in the top room it should be about 40° Cent., in the second
from 40° to 50° Cent., and in the lowest from 70° to 90° Cent. The hot air is
consequently caused to pass first into the bottom rooms. The heating apparatus
supplying the hot air may be of any suitable construction, and it may be advan-
tageously placed in a chamber below the bottom room. The hot air from the
heating apparatus must, before entering the bottom room, be mixed intimately with
cold air in a chamber, preferably in that below the bottom drying room, in order that
it may have the requisite average temperature. The warm air passes through the
previously warmed malt, in the slowly revolving drum of the bottom room and
passes thence through a pipe into the second room. Should it be too warm, a
quantity of cold air is admitted through a valve to, mix therewith. From the
second chamber the air, after having passed through and imparted a portion of its
heat to the malt in the slowly révolving drum, passes through a pipe into the top
If necessary, cold air is again admitted through a valve to reduce the
temperature. From the top room the air is drawn off by an exhaust fan, being
thereby caused to pass through the malt in the slowly revolving drum which-thus
receives a preliminary drying.
room.
With this, method of continuous drying all loss of heat is avoided, and as the
driving of the drums, as also all manipulations required during the drying are
effected external to the drying rooms, all possibility of the entrance of bad smells
: and noxious vapours into the drying rooms is avoided.
.
The rotation of the drums insures that the whole of the malt contained therein
shall be uniformly dried.
In order that the air shall be caused to pass through the entire body of malt,
the exhaust pipe opens into a box situated at one point of the circumference of
the drum, which box has fixed.to it cloths that apply themselves to the surface of
the drum and are held in position by cords chains or bands passing round the
drum. For preventing the too rapid wear of the cloths the drums are provided
with external stiffening ribs of half round iron which slide upon the cloths as the
-drum rotates.
.
The burning or roasting of malt as heretofore practised robs it of many of its
qualities that are of value in brewing, and affords a product which often imparts
to the beer a burnt flavour. With the present improved method the malt can be
at the same time roasted to the required degree in the drum of the lowest drying
room. For this purpose a sheet metal shield of parabolic section is applied to a
*part of the drum, in the focus of which shield is a heating pipe that can be shut
off or regulated. This heating pipe can be heated to the required degree, either by
means of the before mentioned heating apparatus, or preferably by means of a
'special fire in another chamber, and the heat radiated from the pipe and reflected
by the parabolic shield on to the entire surface of the drum enclosed thereby will
effect the roasting of the malt successively brought in front of the shield by the
rotation of the drum. The parabolic shield has a slit or opening through which
'the space enclosed thereby communicates with the box before-mentioned leading
"to the exhaust pipe. In this arrangement the before-mentioned cloths are connected
to the shield.
f
Instead of three drums, only two or more than three can be employed without
departing from the nature of this invention; according to the description of malt

page_text: to be produced and the degree of heat at which the drying and roasting is to be
effected.
The above described method of operating and apparatus can be used with
advantage not only for treating malt, but also in all cases where a moist substance
5 has to be dried, and for some purposes a single drying drum of the described
construction can be used.