Year: 1887

page_text: Date of Application, 24th Mar., 1887.
Specification Accepted, 28th June, 1887,
[Communicated from abroad by FREDERICK WILLIAM WIESEBROOK, of New York,
in the County and State of New York, United States of America, Mining
Engineer.]
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane in the (ounty
of Middlesex, Fellow of the Institute of Patent Agents, do hereby declare the nature
of this invention to be as follows:-
This invention relates to a process for drying and cooling malt suitable for the
manufacture of very pale beer without the use of unmalted material, and clearing the
malt from rootlets, sprouts or other substances. It relates also to apparatus for
performing this process by the action of currents of air, for collecting particles carried
off by the air and for utilising the heat applied in drying. This apparatus is applicable
for drying not only malt but also grain and other like substances.
1 will describe my invention referring to the accompanying drawings. Fig. 1 is an
elevation, partly in section, of the drying and cooling apparatus; Fig. 2 is a vertical
section to an enlarged scale on the line of Fig. 1; Fig. 3 is a section of the
drying cylinder on the line y of Fig. 1; Fig. 4 is a section similar to Fig. 3,
shewing a modified construction; Fig. 5 is a section on the line of Fig. 4.
In drying malt, especially when it has to be of high quality suitable for pale beer,
it is necessary to eliminate the moisture very gradually and to remove it completely
from the inner kernel of the grain without applying such heat as will discolor the
albumenoids that lie closely to the inner shell, or will produce contraction or shrivelling
of the outer shell or hull, which surrounds the soft core of the grain, as this injures
the appearance of the malt and renders the complete extraction of the inner moisture
very difficult.
According to my invention the malt, while in agitation, is subjected to the action
of a current of air the temperature of which is gradually increased to about 100° Fahr.
at which temperature it is maintained until the rootlets or sprouts are dried and carried
off by the blast. The temperature is then gradually increased to 125° or 160° F., at
which point the drying process is completed. Cold air is then driven through the
malt until it is quite cooled and then the malt is ready for storage without requiring
to be cleaned. Malt thus treated is perfectly dried, is free from discoloration of

page_text: the albumenoids and is therefore especially adapted to the manufacture of pale beer
of high quality; it is, moreover, sightly, without wrinkled or shrivelled appearance
and it may be safely stored for an indefinite period. By this treatment I avoid the
production of what is known as "glass malt" which results from the absorption of
moisture by malt which is nearly dry, and the heating of this malt which converts
the starchy portion of the grain into a baked paste.
Referring to the drawings, 1 is the brick work of the air heating furnace in the walls
of which are vertical flues 2 receiving external air by openings 3 near the bottom and
communicating at the top with 4 the uppermost of a series of air heating boxes 4, 5
and 6. These are made of metal plates and are arranged in a chamber above the fire
grate 7, the combustion chamber 8 and bridge 9. The lowest heating box 6 is protected
from the direct action of the flames by a fire brick arch 10. The products of combustion
pass to the chimney 11. by tubes 12, through the air heating boxes and by passages 13
between and above the boxes. From the lowest heating box 6 a pipe 14 extends
through the side wail and communicates by a pipe 15 with a rotating drying cylinder 16.
The pipe 15 has a branch 17 with a valve 18, by opening which cold air can he
admitted to the pipe 15 and cylinder 16. The cylinder is supported on rollers 19
mounted in brackets 20 fixed on beams 21 which rest upon firm foundations 22. The
cylinder 16 has a double shell of metal with the space between the shells filled with non
heat conducting material 23. Within the cylinder are fixed stirring or agitating shovels
or blades 24; a sliding door 25 worked by a screw 26 serves to open and close an
opening or manhole through which the material to be treated is introduced and
removed. The outermost of the stirrers 24 are fixed several inches from the shell of
the cylinder, so that when the cylinder is turned with its manhole downwards, the
dried grains can be freely discharged. At the side of the cylinder and connected with
it by an inclined spout 28, is situated the collecting chamber 27. The upper end of
the spout 28 is enlarged to circular form and fitted to an annular groove of the cylinder,
as shown in Fig. 5, so that while the cylinder rotates and the spout remains stationary
there is little or no leakage of air at the joint. The spout 28 is supported by
standards 29, and has on its upper side an orifice and cover 30 which can be opened
for obtaining samples of the material operated on.
On the top of the collecting chamber 27 is placed an exhaust fan 31 drawing out
moist air by an elbow 32 and discharging it by a pipe 33. A door 34 gives access to
the chamber 27 when required. The cylinder shewn in Figs. 1 and 3 is more
particularly designed for drying and cooling malt or grain. In some cases, I modify
the cylinder as shewn by Figs. 4 and 5. The shovels or blades are omitted and a set
of blades, wings or brushes 35, mounted on a shaft 36, revolve in contact with the
interior surface of the cylinder. The shaft 36 is mounted in arms 37 which project
from a sleeve 38, surrounding a shaft 39, both of which extend through the openings
at the sides of the cylinder and take their bearings on the stationary pipes 15 and 28;
the shaft has fixed on it a driving pulley 40 and the sleeve has a weighted arm 41
outside the cylinder counter-balancing the arms 37 and what they carry within the
cylinder. On the shaft 39 is a toothed wheel 42, which, through a pinion 43, drives a
wheel 44 on the shaft 36, causing the blades, wings or brushes 35 to rotate ; this
gearing is enclosed in a casing 45 fixed to the sleeve 38. The blades, wings, or
Brushes 35 throw the material upward, agitating it, and exposing it to the current of
air, and they also keep the interior surface of the cylinder clear from adhering
substances.
In drying and cooling malt, the cylinder 16, shewn in Figs. 1 and 3, charged about
half full with the moist or wet grain, is caused to rotate the valve 18 is opened and air
is drawn by the action of the fan 31 through the cylinder, the spout and the collecting
chamber. This being continued for a short time, according to the condition of the
malt, the cold air valve is so regulated in connection with the hot air supply that a
small proportion of hot air from the furnace is mingled with the cold air current and
this proportion is gradually increased until the temperature of the inflowing air reaches
about 100° F. This temperature is maintained until the rootlets or sprouts, which
are the first to dry, are carried out of the cylinder into the collecting chamber 27.

page_text: The temperature is then gradually increased until it reaches about 160° F., when the
drying is completed.
Air at the external temperature is then drawn through the malt until it is cooled
when it is removed from the cylinder to be stored.
The drying being thus effected without discoloring the albumenoids, the malt can be
used to produce very pale beer, having all the aroma of genuine malt beer, instead of
being like the pale beers usually made, for which, owing to discoloration of the
albumenoids more or less unmalted material, such as corn or rice, is mixed with the
malt.
During the drying and cooling of the malt, the dust, rootlets or sprouts are detached
and carried by the air current to the collecting chamber, where they are deposited.
The separation of the impurities is accomplished mostly during the gradual increase
of the temperature up to 100° F, when the rootlets being thin and light are quickly
dried and, when dry are easily detached and carried off by the air current.
The rootlets generally contain a principle known as "asparagine," which has a bitter
and disagreeable flavour liable to be communicated to the malt unless the moist
rootlets are rapidly separated from it. The collecting chamber 27 is constructed of
such area that the speed of the air current through it is reduced sufficiently to permit
the particles to deposit.
In the heating part of the apparatus the air is made to pass through the boxes 4, 5, 6,
in a direction opposite to that in which the products of combustion pass, as indicated
by the arrows in Fig. 2, being thus effectually heated while the heat delivered to the
walls is utilised in heating the air ascending the flues 2.
A thermometer 46 on the pipe 15 indicates the temperature of the air entering the
cylinder 16.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :-
1. The process substantially as herein described for drying and cooling malt and
like materials by first subjecting the material, while agitated, to a current of air
gradually heated to about 100° F. and maintained at that temperature until the
rootlets are removed, then gradually raising the temperature to about 160° F., and
finally cooling the material by a current of air at the external temperature.
2. In apparatus for drying and cooling malt or like materials, the combination of a
furnace for heating air, a rotating drying cylinder, a collecting chamber and an
exhaust fan with their communications arranged and operating substantially as
described.
3. The construction of air heating furnace for drying apparatus wherein air,
ascending flues in the side walls, passes to and fro horizontally through heating boxes,
through which pass, in the opposite direction, products of combustion from a fire
below, substantially as described with reference to Figs. 1 and 2 of the accompanying
drawings.
4. The construction of drying cylinder, having a double shell lined with noncon-
lucting material and transverse stirrers or shovels fixed therein, and mounted on
ollers on which it is caused to revolve, substantially as described with reference to
Figs. 1 and 3.
5. The modified construction of drying cylinder, substantially as described with
eference to Figs. 4 and 5, having within it blades, wings or brushes caused to revolve
n contact with the internal surface of the cylinder by gearing within a casing.
Dated th: 541 1.— CAL L 1000
ABEL & IMRAY,
Agents for the Applicant.