Year: 1896

page_text: We, Dr. CARL GUSTAV JOBST MÖLLER, of 19 Friedrich-Wilhelm Strasse Berlin,
and Professor PAUL PFEIFER of 7 Bismarckstrasse Braunschweig, both in the Empire
of Germany, do hereby declare the nature of this invention to be as follows:-
Our invention relates to a drying apparatus in which a number of drying chambers
and as many surface heating devices are so combined that the air used for drying
passes first through a heating register, then through a drying chamber, next through
the second heating register and the second drying chamber and so on, and leaves
the last drying chamber in a highly heated condition and saturated with water
vapour.
In the drying apparatus heretofore employed the air used for the drying is usually
heated by a surface heating device and conducted through a drying chamber. The
drying air is considerably cooled in its passage through the material owing to the
vaporization of the water, and leaves the drying apparatus at a comparatively low
temperature. But the cooler the drying air is on leaving the material to be dried
the less water vapour is carried away by it and the more drying air will be needed
for the vaporization of a certain quantity of water.
With artificial drying the operation always takes place under the most favourable
conditions if the drying air is highly heated and saturated with water vapour on
leaving the drying apparatus for of the amount of heat to be used the greatest
portion will then be spent in the vaporization of the water, and the smallest portion
in heating the drying air from the initial temperature at the inlet to the final
temperature at the outlet from the drying apparatus. In the ordinary drying
apparatus wherein the drying air escapes at a low temperature more heat is often
spent in heating the air from the temperature at the inlet to that at the outlet
than is rendered available for vaporizing the water.
The combination of a number of surface heating devices and drying chambers as
before stated has for its object to render the heat necessary for the artificial drying
available as completely as possible for the vaporization..
The drying apparatus is provided with several drying chambers and the same
number of surface heating devices. At the end of the last drying chamber is an
.exhauster which draws the air from this chamber. All the drying chambers and
surface heating devices are securely shut off from the atmospheric air excepting
the opening through which the atmospheric air can pass to the first surface heating
device. Accordingly the suction of the exhauster causes a movement of air in the
above stated manner, inasmuch as the air passes first through the surface heating
device, then through the drying chamber, next through the following surface heating
device and so on, finally passing through the last drying chamber. The atmospheric
air entering at the inlet, is heated by the heating device or register from the initial
temperature to to a temperature t₁, takes up moisture in its passage through the
material to be dried in the first heating chamber, and cools again to a temperature t₁₁
which is however higher than the temperature to at the inlet. At the end of this
first chamber there is consequently air which is warmer than the atmospheric air

page_text: and at the same time air containing a greater quantity of water.
This air is now
conducted through the communicating channel to a second heating register, and is
heated therein to a temperature, which is higher than t, and is cooled down
again in its passage through the material to be dried, in the second heating chamber
while receiving water to the temperature t,' which is again higher than t₁. In
this manner the heating and taking up of water are repeated until the air is drawn
off at the end of the last drying chamber at a high temperature and with much
moisture. Therefore the desired object is achieved as completely as possible by such
an arrangement in a row.
The quantity of air drawn off at the exhaust is comparatively small by reason of
the great quantity of water contained in the air, and the movement of air in the
several drying chambers is often slower than is desirable for many materials to be
dried. Moreover the beating by surface heating devices, owing to the slow
movement of the air, is not good.
In order to obviate these inconveniences use is made of a drying apparatus
which presents exactly the same arrangement of the drying chambers and of the
surface heating devices as that above described. The mode of conducting the air
and therefore the advantages afforded thereby remain the same. Besides the slow
principal movement of the air we provide also for an energetic secondary movement
of the air, which is produced by fans and circulating channels. The fans force the
air enclosed in a drying chamber in a continual eyele through the material to be
dried, the fan, the circulating channel and the surface heating device.
energetic secondary movement the drying process is accelerated and the effect of
the surface heating device considerably increased.
By this
It is immaterial bow the drying chambers are shaped. In lieu of the said chambers
use may also be made of channels, shafts or tubes, movable drying chambers,
drums or boxes.
We sometimes arrange the drying chambers so that they constitute rotary drums.
The material to be dried is introduced through the feed funnel, moves through the
upper drum, drops from the same through a funnel into another drum and so on to
a funnel, from which it is removed to the outside by a conveyor. The drying air
entering through the inlet opening circulates through the heating register, through
the drum, further through a second heating register and a second dram, and finally
through the last heating register and drum and is drawn from the drying apparatus by
the exhauster. The repeated heating of the drying air and its reception of water
therefore take place in just the same way as in the drying apparatus above described.
By the rotary drums the material to be dried is at the same time kept in continual
movement. The movement of the material to be dried through the drying chambers
has the advantage that the preliminarily heated air meets the cool material to be
dried, and that the doubly heated drying air meets in the second drum the warmer
material to be dried, and that the warmest drying air meets the mostly heated
material to be dried in the third drum. With this arrangement the air
and material to be dried move therefore in the same direction. This current in the
same direction possesses a great advantage, because moisture can never be precipitated
'from the warm air on to the cold material to be dried, such as is almost always
the case with the apparatus heretofore generally constructed for a counter current.
Likewise for the purpose of producing a more energetic movement of air in the
drying drums and increasing the heating effected by the surface beating devices,
a fan is provided for each drum and produces a continual cycle of the air which is
enclosed in a drum through the circulating channel, the heating register and the
drum. In other respects the arrangement of the drying chambers and beating
registers in series is the same as above described.
In order to enable the current of the air and material in the same direction also
to be utilized in stationary drying chambers, we may construct a drying apparatus
wherein the drying chambers and the heating registers are arranged in the same
manner as in the apparatus first herein described. The chambers in the form of
channels are however arranged close together side by side, and may at times be

page_text: connected with each other through sliding doors so that the material to be dried and
lying on carriages or trucks can be moved from one channel to another. As soon as
all the doors are closed and the exhaust is set in operation we obtain the desired
current of air in the same direction with multiple heating and reception of moisture.
The connecting channels between the chambers and the surface heating devices are
situated underneath the drying chambers in this arrangement.
In another modification we arrange a corresponding drying apparatus wherein for
the purpose of accelerating the drying and increasing the heating effect of the surface
beating device an energetic auxiliary movement is produced in the several drying
channels by fans. The closing of the doors between the several chambers is obtained
by the material to be dried and placed upon the carriage provided with several floors,
or by special closing plates arranged on the carriage. The circulating channels are
situated underneath the drying chambers, and the communicating channels obliquely
above the drying chambers.
As the drying air in its passage through the described drying apparatus is by
degrees heated more and more, it will be expedient to arrange the surface heating
devices in such a manner that the temperature of the heating surfaces with which the
drying air comes in contact first is lower than the temperature of the heating surfaces
finally touched by the drying air. Accordingly in these drying apparatus the
arrangement of the heating surfaces is of extreme importance. It will usually
be possible to combine existing sources of heat (exhaust steam) with new
sources of heat. The employment of exhaust steam occurs more frequently.
It is particularly advantageous to utilize the heat of the exhaust steam in the first
heating registers, the last heating registers being simultaneously supplied with fresh
steam, superheated steam, hot water, products of combustion, and the like, and it
should not be overlooked that in this combination a whole series of exceedingly
valuable results is achieved. Thus for instance the rapid withdrawal of the latent
heat of the exhaust steam by energetic circulation of cold air round the heating
registers, the great effectiveness of the surfaces of the heating device, the preliminary
heating of the drying air and of the material to be dried for drying with heat freshly
used. In this manner it is possible to utilize the direct heating almost wholly for the
vaporization, and to achieve as a final result very high figures as regards the
vaporization per unit of the fuel employed.
If other sources of heat are at disposal they may likewise be utilized in these drying
apparatus. In the drying of pottery the waste heat of the burnt articles is for
instance often at disposal for purposes of drying. When there are separate burning
chambers the drying chambers may be so connected with the burning chambers
through channels that the furnace chambers will directly take the place of the surface
heating devices.
In case there is only one furnace chamber the waste heat is rendered available in
the following manner. The drying apparatus remains exactly the same as hereinbefore
described. The heating registers are supplied by the waste heat of the furnace
inasmuch as a fan forces a strong current of air through the burnt articles contained
in the furnace chamber and designed to be cooled, through a channel and through
the heating registers back through the fan and a channel into the furnace. The air
is heated in its passage in the furnace chamber and is cooled again in its passage
through the heating registers in order to pass in a moderately warm state through the
fan and to return into the furnace. Here, too, the first beating register has the
highest temperature and the temperature of the following heating registers become
gradually less.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, W.C., Agents for the Applicants.

page_text: Improvements in Drying Apparatus.
We, Dr. CARL GUSTAV JOBST MÖLLER, of 19 Friedrich-Wilhelm Strasse, Berlin,.
and Professor PAUL PFEIFER, of 7 Bismarckstrasse, Braunschweig, both in the
Empire of Germany, 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 :-
Our invention relates to a drying apparatus in which a number of drying chambers
and as many surface heating devices are so combined that the air used for drying
passes first through a heating register, then through a drying chamber, next through
the second heating register and the second drying chamber and so on, and leaves
the last drying chamber in a highly heated condition and saturated with water
vapour.
In the drying apparatus heretofore employed the air used for the drying is usually
heated by a surface heating device and conducted through a drying chamber. The
drying air is considerably cooled in its passage through the material owing to the
vaporization of the water, and leaves the drying apparatus at a comparatively low
temperature. But the cooler the drying air is on leaving the material to be dried
the less water vapour is carried away by it and the more drying air will be needed
for the vaporization of a certain quantity of water.
With artificial drying the operation always takes place under the most favourable
conditions if the drying air is highly heated and saturated with water vapour on
leaving the drying apparatus, for of the amount of heat to be used the greatest
portion will then be spent in the vaporization of the water, and the smallest portion
in heating the drying air from the initial temperature at the inlet to the final
temperature at the outlet from the drying apparatus. In the ordinary drying
apparatus wherein the drying air escapes at a low temperature more heat is often
spent in heating the air from the temperature at the inlet to that at the outlet than
is rendered available for vaporizing the water.
The combination of a number of surface heating devices and drying chambers as
before stated has for its object to render the heat necessary for the artificial drying
available as completely as possible for the vaporization.
In the accompanying drawing
Figure 1 is a longitudinal section of the improved drying apparatus.
Figure 2 is a plan of the same.
Figure 3 is a longitudinal section of another form of drying apparatus.
Figure 4 is a plan of the same.
Figure 5 is a section of a modified form of apparatus in which rotary drums are
used.
Figure 6 is a modification of Figure 5.
Figure 7 is a longitudinal section of another form of drying apparatus.
Figure 8 is an horizontal section of Figure 7.
Figure 9 and 10 show a longitudinal and an horizontal section of another form of
apparatus and
Figures 11 and 12 show still further modifications.
The drying apparatus, shown in Figures 1 and 2 is provided with several drying
chambers a₁ ag az
... and the same number of surface heating devices b₁ b, b3. At
the end of the last drying chamber a, is an exhauster e which draws the air from this
last chamber a. All the drying chambers and surface heating devices are securely
shut off from the atmospheric air, excepting the opening c through which the
atmospheric air can pass to the first surface heating device b₁. Accordingly the suction
of the exhauster e causes a movement of air in the above stated manner, inasmuch as the

page_text: air passes first through the surface heating device b₁, then through the drying
chamber a₁, then through b₂ and as, through b and a, and finally passing through
and a. The atmospheric air entering at the inlet c is heated by the heating
device or
register by from the initial temperature to to a temperature t₁, takes up moisture in its
passage through the material to be dried in the first heating chamber a₁, and cools
again to a temperature t, which is however higher than the temperature to at the
inlet. At the end of this first chamber there is consequently air which is warmer than
the atmospheric air and at the same time air containing a greater quantity of water.
This air is now conducted through the communicating channel d₁ to a second heating
register, by, and is heated therein to a temperature t, which is higher than t, and is
cooled down again in its passage through the material to be dried, in the second
heating chamber a, while receiving water, to the temperature t,' which is again higher.
than . In this manner the heating and taking up of water are repeated until the
air is drawn off at the end of the last drying chamber a, at a high temperature and
with much moisture. Therefore the desired object is achieved as completely as.
possible by such an arrangement in a row.
The quantity of air drawn off at the exhaust e is comparatively small by reason of
the great quantity of water contained in the air, and the movement of air in the several.
drying chambers is often slower than is desirable for many materials to be dried.
Moveover the heating by surface heating devices, owing to the slow movement of the
air, is not good.
In order to obviate these inconveniences use is made of a drying apparatus
represented in Figures 3 and 4, which presents exactly the same arrangement of the
drying chambers a₁ ag as
and of the surface heating devices b₁ b₂ ba
.. as that represented in Figures 1 and 2. The mode of conducting the
air and therefore the advantages afforded thereby remain the same. But besides
the slow principal movement of the air we provide also for an energetic
secondary movement of the air, which is produced by fans fi fafs and circulating
channels 91 92 93,
The fans force the air enclosed in a drying chamber in a
continual cycle through the material to be dried, the fan f, the circulating channel g
and the surface heating device b. By this energetic secondary movement the drying
process is accelerated and the effect of the surface heating device considerably
increased.
It is immaterial how the drying chambers a₁ a. . . are shaped. In lieu of the
said chambers a₁ a, . . which are represented in Figures 1 to 4, use may also be made
of channels, shafts or tubes, movable drying chambers, drums or boxes.
Thus Figure 5 illustrates a drying apparatus in which the drying chambers constitute
rotary drums a₁₂ az.
The material to be dried is introduced through the feed funnel h₁, moves through the.
upper drum a,, drops from the same through a funnel h₂ into another drum a, and so
on to a funnel i from which it is removed to the outside by a conveyor. The drying
air entering through the inlet opening e circulates through the heating register b₁
through the drum a₁, further through the heating register b, and a second drum a,
and finally through the last heating register b, and the drum a, and is drawn from the
drying apparatus by the exhauster e. The repeated heating of the drying air and its
reception of water therefore takes place in just the same way as in the drying.
apparatus represented in Figures 1 and 2. By the rotary drums the material to be dried
is at the same time kept in continual movement. The movement of the material to be
dried first through the drying chamber a₁, then through a, and finally through as has the
advantage that the preliminarily heated air meets the cool material to be dried, and that
the doubly heated drying air meets in the second drum a, the warmer material to be..
dried, and that the warmest drying air meets the mostly heated material to be dried in
the drum a3. With this arrangement the air and material to be dried move therefore
in the same direction. This current in the same direction possesses a great advantage,
because moisture can never be precipitated from the warm air on to the cold material
to be dried, such as is almost always the case with the apparatus beretofore generally
constructed for a counter current.

page_text: Likewise for the purpose of producing a more energetic movement of air in the
drying drums and increasing the heating effected by the surface heating devices, in
the drying apparatus shown in Figure 6 a fan is provided for each drum and
produces a continual cycle of the air which is enclosed in a drum through the
circulating channel, the heating register and the drum. In other respects the
arrangement of the drying chambers and heating registers in series is the same as in
Figure 5.
.In order to enable the current of the air and material in motion in the same direction
also to be utilized in stationary drying chambers, in Figures 7 and 8 a drying
apparatus is represented wherein the drying chambers a₁ a...
and the heating
registers b₁ b
are arranged in the same manner as in the apparatus shown in
Figures 1 and 2. The chambers in the form of channels a₁ a₂ . . . . . are however
arranged close together side by side, and may at times be connected with each other
through sliding doors so that the material to be dried and lying on the carriages or
trucks can be moved from the channel a₁ to the channel a,, and from a² to a³ and so
As soon as all the doors are closed and the exhaust is set in operation we
obtain the desired current of air in the same direction with multiple heating and
reception of moisture. The connecting channels between the chambers a and the
surface heating devices b are situated underneath the drying chambers in this
arrangement.
on.
In Figures 9 and 10 is arranged a corresponding drying apparatus wherein for
the purpose of accelerating the drying and increasing the heating effect of the surface
heating device an energetic auxiliary movement is produced in the several drying
channels by fans fi f
The closing of the doors between the several
chambers a, a, aз. . . is obtained by the material to be dried and placed upon the
carriage provided with several floors, or by special closing plates arranged on
the carriage. The circulating channels 91 92 9, are situated underneath the drying
chambers, and the communicating channels d₁ dz obliquely above the drying
chambers.
...
It is
As the drying air in its passage through the described drying apparatus is by degrees
heated more and more, it will be expedient to arrange the surface heating devices in
such a manner that the temperature of the heating surfaces b₁ and b, with which the
drying air comes in contact first is lower than the temperature of the heating
surfaces b3 b4 finally touched by the drying air. Accordingly in these drying
apparatus the arrangement of the heating surfaces is of extreme importance. It will
usually be possible to combine existing sources of beat (exhaust steam) with new
sources of heat. The employment of exhaust steam occurs more frequently.
particularly advantageous to utilize the heat of the exhaust steam in the first heating
registers by b₂, the last heating registers bs b4 being simultaneously supplied with fresh
steam, superheated steam, hot water, products of combustion, and the like, and it
should not be overlooked that in this combination a whole series of exceedingly
valuable results is achieved. Thus for instance the rapid withdrawal of the latent heat
of the exhaust steam by energetic circulation of cold air round the heating registers,
the great effectiveness of the surfaces of the heating device, the preliminary heating
of the drying air and of the material to be dried for drying with heat freshly to
be applied. In this manner it is possible to utilize the direct heating almost wholly
for the vaporization, and to achieve as a final result very high figures as regards
the vaporization per unit of the fuel employed.
If other sources of heat are at disposal they may likewise be utilized in these
drying apparatus. In the drying of pottery the waste heat of the burnt articles is
for instance often at disposal for purposes of drying. When there are separate
burning chambers the drying chambers a, a, . . . . Figure 11, may be so connected
with the burning chambers b₁ b₁. . . . . through channels d₁... that the furnace
chambers will directly take the place of the surface heating devices.
In case there is only one furnace chamber rq Figure 12, the waste heat is rendered
available in the following manner. The drying apparatus remains exactly the same
as represented in Figure 10. The heating registers b₁ b₂ bz... are supplied by the

page_text: waste heat of the furnace rq, inasmuch as a fan n forces a strong current of air
through the burnt articles contained in the furnace chamber rg and designed to be
cooled, through a channel o and through the beating registers b, ba b, b₁ back through
the fan and the channel p into the furnace. The air is heated in its passage from r
to q and is cooled again in its passage from b, to b, in order to pass in a moderately
warm state through the fan and to return into the furnace. Here, too, the heating
register b, has the highest temperature and the temperatures of the following heating
registers b, b, o₁ becomes gradually less.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
First. A drying apparatus, in which two or more drying chambers a₁ ag . . . are
connected with each other and with as many heating registers b
in such
a manner that the drying air will be compelled to pass in succession first through a
heating register b₁, then through the first drying chamber a,, next through a second
heating register b, and the second drying chamber ag, and so on, in order that it may
leave the drying chamber highly heated and saturated with water vapour.
Second. In a drying apparatus of the kind characterized in the first claim the
arrangement of fans fifa and circulating channels 9₁₂ for producing a
circular movement of the drying air within each drying chamber and the surface
heating device, appertaining thereto, for the purpose of obtaining a better heating
effect of the heating register and for enabling water to be better given off by the
material to be dried in energetically moved drying air.
Third. In a drying apparatus of the kind characterized in the first and second claims
the arrangement of two or more rotary drums situated one above the other and through
which air and material to be dried pass in the same direction so that first the upper
drum, then the drum below and so on are traversed, for the purpose of obviating the
precipitation of water upon the material to be dried."
Fourth. A constructional form of the apparatus characterized in the first and
second claims, wherein the drying chambers a₁ a
with each other so that the material to be dried and lying upon the carriago can
..may periodically be connected
be moved in succession through the several chambers during the drying.
Fifth. In drying apparatus of the kind characterized in the first to the fourth
claims the arrangement of heating registers b₁ b . . . . in such a manner that the
heating registers b₁ b₂ first touched by the drying air are less highly heated than the
following heating registers b. 4, for the purpose of allowing the drying air to
pass off at as high a temperature as possible and to contain as much moisture as
possible.
Sixth. In drying apparatus of the kind characterized in the first claim the
substitution of the special surface heating devices by furnace chambers b₁ b
which are filled with blocks to be cooled and are connected by channels with the
several drying chambers (Figure 11).
Seventh. In drying apparatus of the kind characterized in the first claim the heating
of the heating registers b₁ b... by the waste hot-air of a furnace channel,
which air is drawn from the channel by means of a fan, forced through the heating
egisters and conducted back again into the channel (Figure 12).
Dated this 6th day of November 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.