Improvements in Apparatus for Drying Bricks, Earthenware, Cement Lumber and the like.
Year: 1899

page_text: Date of Application, 2nd Jan., 1899-Accepted, 4th Mar., 1899
COMPLETE SPECIFICATION.
Improvements in Apparatus for Drying Bricks, Earthenware, Cement
Lumber and the like.
I, MAX WOLFF, of 89, and 91, Sumner Street, Southwark, in the County of
London, Manufacturer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
My invention relates to apparatus for drying bricks, earthenware, cement,
lumber and the like, and is chiefly designed to improve the construction and
increase the efficiency of apparatus such as is described in the Specification of
fermer Letters Patent granted to me and dated 26th November 1895, No. 22598.
The apparatus described in the said former specification comprises a long
drying chamber along which the material to be dried is conveyed in cars or
trucks running on rails, a heating chamber arranged below and opening into
the said drying chamber, a conduit situated above the said drying chamber and
communicating with a chimney arranged at or near the inlet-end of the drying
chamber, and with the said drying chamber through openings controlled by
dampers. This conduit has heretofore been employed for removing the
smoke" (produced during the drying process) from the drying chamber as rapidly
as possible so as to prevent its injurious action on the fresh bricks, and after-
wards allowing it to escape through the chimney.
water
Now it has been found in practice that the temperature of the drying chamber,
in the apparatus as hitherto constructed, has been too high at the inlet-end
where the fresh or undried bricks are admitted, and that the consequent sudden
elevation of temperature of the bricks at the commencement of the process has
been the cause of the production of "water smoke" and also, by too rapidly
drying the exterior, of the formation of a hard crust over the surface of the
bricks which prevents the ready escape of moisture from the interior and causes
them to crack in the subsequent treatment.
Moreover, by reason of the conduit above the drying chamber, opening directly
into the chimney, a considerable amount of heat has been lost, the hot, air
escaping from the said conduit without imparting its heat either to the bricks
or other material to be dried, or to the air entering the dryer.
Now according to my present invention I provide for reducing the tempera-
ture of the drying chamber at the inlet end, and increasing the temperature at
the outlet or delivery end thereof, thus enabling the drying process to be effected
very uniformly, and consequently in a shorter time than heretofore, whilst .
utilizing the heat, supplied to the apparatus more economically than heretofore,
water smoke."
and preventing the formation of "
For this purpose I close the direct communication between the said conduit
and the chimney and I provide the said conduit with an aperture or apertures
extending longitudinally from a point near the inlet-end of the drying chamber
to or nearly to the middle of the said chamber, and communicating with the
external air, so as to permit the entrance of cold air into the said conduit,
which air will descend through suitable apertures into the drying chamber,

page_text: or less,
and thence into the heating chamber where it will be heated and whence it will
rise into the drying chamber to again act on the material to be dried. The
cold air entering the apparatus as above-mentioned, will mix more
during its downward motion towards the heating chamber, with the air which
has entered the dryer through the air-conduit beneath the floor of the heating
chamber, and will finally mix therewith in the drying chamber and be carried
away to the chimney by the draught in the said drying chamber. The result
of this arrangement is that the temperature is lowered at the inlet end of the
drying chamber by the cold air from the conduit above the said drying chamber,
whilst the motion of the air is somewhat reduced at the outlet end of the said
drying chamber and the temperature allowed to rise higher than heretofore thus
producing a very strong drying_action.
In the accompanying drawing I have shown how my said invention may be
conveniently and advantageously carried into practice.
Figure is a partial longitudinal section of a dryer having my improve-
ments applied thereto, and
Figure 2 is a transverse section on the line, Figure 1, drawn to an
enlarged scale.
The parts which correspond to those described and shown in my said former
specification are marked with similar reference numerals.
The conduit or channel 19 is closed at the end next the chimney or shaft 6
as shown, and in the lateral walls thereof are formed apertures A, which, in a
drying chamber 100 to 110 feet long, for example, extend from point about
20 feet from the base of the chimney, to a point about 45 feet therefrom, i.e. from
the commencement of the heating chamber 8 to about the middle of the second
heating coil 17 so as to allow the entering air to mix with the warm air in the
inlet half of the drying chamber before being carried away to the chimney 6,
that is to say, with the air which has entered the drying chamber through the
air-conduit 43, apertures 41 and heating chamber 8. The apertures A lie im-
mediately beneath the eaves of the roof 21 and are thus protected against rain,
snow, etc. Additional cold air inlet-apertures may also, if desired, be formed
in the ceiling 20 and provided with sliding doors, flaps or the like, for example,
as indicated in dotted lines on Figure 2.
The heating chamber 8, in my improved apparatus, does not extend as far as
the chimney 6, as in the dryer shown in Figure 1 of the drawings accompanying
my said former specification, but, in the example given, commences at a point
about 20 feet from the base of the said chimney, thus enabling the heated air
to remain for a sufficient length of time in contact with the material to be dried
to ensure its taking up the maximum amount of moisture.
The operation of my improved apparatus is as follows:-The air from the
exterior of the apparatus enters the conduit 19 through the apertures A and,
by reason of its greater density, passes down, through the openings 23 in the
ceiling 20, into the drying chamber 1 where it partly mixes with and cools the
hot air and vapours therein. Some of the cold air finally enters the heating
chamber 8 through the openings 9, where it is heated by the coils 16, 17, 18,
and ascends again into the drying chamber. The hot air and vapours are car-
ried along the drying chamber by the draught to the shaft or chimney 6, whereby
they are removed from the dryer. In this manner, it will be seen that a circula-
tion of air is set up, the air passing into the dryer through the openings A,
thence into the drying and heating chambers 1 and 8, and finally back to the
atmosphere through the chimney 6, this air being additional to that which
enters the dryer through the air-conduit 43. The rate at which the air and
vapours are removed from the drying chamber 1 through the chimney 6 can
be increased or diminished as desired by raising or lowering the sliding doors
or dampers 25.
It has been found in practice that, by means of this arrangement, bricks or
like material can be gradually heated so as to prevent cracking or undue
hardening of the surface thereof and the moisture thus very rapidly and uniformly

page_text: removed therefrom. Moreover, by gradually raising the temperature of the
bricks I prevent the formation of water smoke" which is very injurious to
tender clay and I am therefore enabled to bring the hot air and vapours from
the conduit 19 into contact with the entering bricks or, like material as above
described without detriment thereto.
By my improvements I am, moreover, enabled to obtain a much higher tem-
perature at the end of the drying chamber at which the cars or trucks 4 pass
cut, than at the inlet end thereof, since the air is not so quickly removed, and
thus, by reason also of the low temperature at which the drying was commenced,
the bricks or other material can be efficiently dried in a much shorter time
than has heretofore been practicable.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim is:-
First. A drying apparatus of the kind herein before referred to, wherein air
is admitted to the drying chamber through a conduit or channel above the same
which is not in direct communication with the chimney or shaft, substantially
as, and for the purposes, herein before described.
Second. In an apparatus for drying bricks, earthenware, cement, lumber and
the like, the combination, with the drying chamber and the heating chamber
below the same, of a conduit situated above the said drying chamber and com-
municating therewith through suitable openings and having lateral openings
for the admission of the external air, substantially as, and for the purposes,
hereinbefore. described.
Third. The improved drying apparatus constructed substantially as herein-
before described with reference to the accompanying drawing, and for the pur-
poses specified.