Improvements in Drying Apparatus.
Year: 1898

page_text: Improvements in Drying Apparatus.
I, CARL WALDEMAR JENSENIUS THOMSEN, of 27, Neubert Strasse Hohenfelde,
Hamburg, in the Empire of Germany, Chemist, do hereby declare the nature of
this invention to be as follows:-
The present invention relates to a drying apparatus, which is hereinafter
described.
The apparatus constructed according to this invention comprises a drum fixed,
by means of the two trunnions in stationary bearings, so that it can rotate,
and tilted slightly or lowered backwards from the feeding end. The amount of
tilt depends upon the nature of the substance to be dried, which, in consequence
of the inclined position of the drum, is conveyed from the front to the rear during
the rotation.
In front of the open or feed end of the drum is the fixed hopper with the inlet-
tube inserted therein and the ventilator or fan upon it, the vanes of which draw
the hot gases or the mixture of hot air from the hot-air chamber surrounding
the drum into the front chamber of the drum, through the caps and the openings
in the walls thereof.
The openings with the caps above them are in the front half of the drum
jacket and at some distance from one another; the rear half of the drum jacket
is not provided with such openings.
The rear open end of the drum terminates in a space which is separated from
the chamber by a wall, and contains a feeding or conveyor screw. The latter
projects into a side outlet pipe, which has a flap or cover with a counterweight.
The above described drum is filled through the feed opening with the substance
to be dried which always remains in motion within the rotating drum, and
which is gradually moved from the front to the conveyor screw chamber
at the rear, whence it is removed dried, by the screw or worm. Through
the pressure of the dried material forced out by the conveyor screw, the flap is
opened against the action of its counterweight, and kept open so long as dried
material is forced against it. The conveyor screw and the outlet-tube are thus
filled with the dried substance, so that no current of air causing troublesome
dust formation can be set up through the said outlet tube and the drum towards
the ventilator.
By means of the ventilator the hot air from the heating chamber is conducted
through the openings into the front space of the drum, and drawn through this
chamber. A thorough stirring up of the moist material and interpenetration
thereof by the hot gases takes place, by which a part of the moisture correspond-
ing to the heat introduced, becomes rarefied. The mixture of steam and hot
gases arising is caused by the ventilator to escape through the outlet.
The material which has been preliminarily dried and which has been conveyed
to the rear chamber of the drum, is here further dried by indirect heat only.
The caps over the openings prevent the dried material from falling into the

page_text: heating chamber, because the material falling through the openings passes into
the caps, and falls from these back, again into the drum, when, in its rotation
the caps come to the top.
:
With the above described drying arrangement, the material put into the drum
is brought into immediate contact with a powerful heating current, only up to a
certain degree of dryness, but, when that degree of dryness has been reached.
in which the inconvenient formation of dust by the direct working of a current of
air and its eddies, which is dangerous with or has a detrimental effect on many
materials, is to be expected, the complete drying is accomplished only by the
heated walls of the drum and by radiation.
This after-drying taking place in a part of the drum free from air currents
gives the further advantage that the fine powder which may be formed by the
rubbing of the dry material on the walls of the drum is not removed by the
ventilator, but remains with the dried portion, or that both a loss of material and
inconvenience to the operators are avoided.
Any sparks which may be present in the hot air are prevented from reaching
the rear part of the drum, therefore they can never come into contact with the
really dry material, so that drying can be carried on without risk of explosion.
Dated this 28th day of February 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in Drying Apparatus.
I, CARL WALDEMAR JENSENIUS THOMSEN, of 27, Neubert Strasse Hohenfelde,
Hamburg, in the Empire of Germany, Chemist, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The present invention relates to a drying apparatus, which is hereinafter
described with reference to the accompanying drawing, in which:-
Figure 1 a vertical longitudinal section of my improved drying apparatus;
Figure 2 is a cross section of the drum on the line 1-2 (Figure 1) and
Figure 3 is a detailed view of the conveyor or worm device for removing the
dried material.
Similar letters refer to similar parts throughout the several views.
The apparatus constructed according to this invention comprises a drum T
mounted, by means of the two trunnions b b in stationary bearings, so that it is
capable of being rotated. The front bearing is somewhat higher than the rear
bearing so that the drum receives a slight inclined position. The amount of the
inclination depends upon the nature of the material or substance to be dried,
which, in consequence of the inclined position of the drum, is conveyed from the
front to the rear during the rotation of the drum.
In front of the feed end of the drum is a fixed hopper d with the inlet-tube a
inserted therein and the ventilator or fan e upon it, the vanes of which draw the
hot gases or the hot air from the hot-air chamber f surrounding the drum, inta
the front chamber t¹ of the drum, through the caps and the openings gl mounted
on and in. the walls thereof respectively.

page_text: The openings g' with the caps 92 above them are provided in the first or front
half of the drum and at some distance from one another; the second or rear
half of the drum is not provided with such openings.
The rear open end of the drum terminates in a space i which is separated from
the chamber by a wall n, and contains a suitable conveyor screw m.
The latter
projects into a tubular outlet casing the bottom of which is closed by a flap
or cover provided with a counterweight 12.
The above described drum is filled or charged through the feed tube a with
the substance to be dried which always remains in motion within the rotating
drum, and which gradually moving from the front to the discharge end of the
drum finally drops out of the latter and into the chamber at the rear, whence
it is removed dried, by the said screw or worm m. Through the pressure of the
dried material forced out by the conveyor screw m, the flap is opened against
the action of its counterweight 12 and kept open so long as dried material is
forced against it. The conveyor screw m and the outlet-tube are thus filled
with the dried substance, so that no current of air causing troublesome dust
formation can be set up through the outlet tube and the drum towards the
ventilator.
By means of the ventilator the hot air from the heating chamber f is conducted
through the openings gl into the front part or chamber t of the drum, and drawn
through this chamber t¹. A thorough stirring up of the moist material and inter-
penetration thereof by the hot gases or air takes place, by which a part of the
moisture corresponding to the heat introduced, becomes vaporised. The mixture
of steam and hot gases arising is caused by the ventilator to escape through the
outlet h.
The material which has been preliminarily dried and which has been conveyed
to the rear part 2 of the drum, is here further dried by indirect heat only.
The caps over the openings g¹ prevent the material to be dried from falling
into the heating chamber f, because the material falling through the openings g
passes into the caps g², and falls from these back again into the drum, when, in
its rotation the caps come to the top.
With the above described drying arrangement, the material put into the drum
is brought into immediate contact with a powerful heating current, only up to
a certain degree of dryness, but, when that degree of dryness has been reached,
in which the convenient formation of dust by the direct working of a current of
air and its eddies, which is dangerous with or has a detrimental effect on many
materials, is to be expected, the complete drying is accomplished only by the
heated walls of the drum and by radiation.
This after-drying taking place in a part of the drum free from air currents
gives the further advantage that the fine powder which may be formed by the
rubbing of the dry material on the walls of the drum is not removed by the
ventilator, but remains with the dried portion, and that both a loss of material
and any inconvenience to the operatives or others are avoided.
Any sparks which may be present in the hot air are prevented from reaching
the rear part of the drum, therefore they can never come into contact with the
really dry material, so that drying can be carried on without risk of explosion.
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. In a drying apparatus the combination of a heating chamber, a drum
mounted therein and having its front part adapted to be traversed by the heating
gases or hot air of the heating chamber, a ventilator device for drawing the heat-
ing medium through the said front part of the drum, and means for preventing
the formation of air currents in the rear part of the drum, substantially as and
for the purpose set forth.

page_text: 2. In a drying apparatus the combination of a heating chamber (
mounted therein and provided in its front part (t¹) with openings (
external caps (92), a ventilator device (e) connected with the feed
the drum, a discharge chamber (2) in connection with the rear
end (2) of the drum but separated from the heating chamber,
preventing the entrance of external air into the outlet of the discharge cham
during the working of the apparatus, substantially as and for the purpose specified.
Dated this 12th day of October 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C:,
Agents for the Applicant.