IMPROVEMENTS IN EVAPORATING VACUUM APPARATUS
Year: 1881

page_text: LETTERS PATENT to Friedrich Hermann Felix Engel, Civil Engineer and
Patent Agent, in the City of Hamburg, Germany, for an Invention of
IMPROVEMENTS IN EVAPORATING VACUUM APPARATUS." A communication
"
PROVISIONAL SPECIFICATION left by the said Friedrich Hermann Felix
Engel at the Office of the Commissioners of Patents on the 20th July
1881.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. "IMPROVEMENTS IN EVAPORATING VACUUM
A communication from Niederberger & Co., of Hamburg, in the
APPARATUS."
German Empire.
This improved evaporating apparatus are specially constructed and very useful
for evaporating liquids and condensing extracts or solutions to a thick and
pastelike consistancy.
The improved apparatus consists of a cylindrical stationary vessel or boiler made
of copper or lined with copper if constructed of iron, which vessel is placed in a
horizontal or slightly inclined position, and receives the evaporating liquid through
a pipe communicating with the upper part of the vessel, and is filled with such
liquid to about one half or two thirds of its height.
Parallel with the horizontal axle of the cylindrical vessel, but placed below the
centre, a wrought iron tube is passed through the vessel, and tightened by stuffing-
boxes, and this tube is lined on its outer surface with copper as far as the tube is
inside the vessel.
Outside of the vessel this tube is supported by brackets, and is at one outer end
furnished with a spur wheel fastened to it, and can be brought in rotation by
another toothed wheel fastened on a shaft driven by a motor. Within the vessel
two copper plates are attached to the tube and fitted to it near the end plates of
the vessel, and between these copper plates a number of copper boiler tubes are
fastened with their ends.

page_text: Each outer side of these copper plates is enclosed in a cover or curved plate
made of copper or bronze. Into one end of the iron tube steam is admitted, and
this steam passes through borings of the tube wall into the next cover, and fills the
boiler tubes with steam, which steam passes through the heating tubes, and condenses
on its way to or after having arrived at the opposite cover, whence the condensed
water is removed by a curved or bent tube, communicating at its one end with
the iron main tube of the heating apparatus.
As the heating or boiling tubes by revolving in the liquid or solution stir these
latters while the apparatus is at work, these tubes very effectively transmit the
heat to all parts of the evaporating liquid, and are especially effective after the
liquid has arrived into a thick or paste like state.
By means of an air pump communicating with the upper part of the vessel, or
preferably with a domne attached or formed to the top of the vessel, all steam
generated within the vessel is removed and a vacuum kept up inside the vessel.
The end plates of the vessel may be furnished with openings covered with
toughened glass or other strong plates of a transparent nature for the purpose of
being able to observe the action of the apparatus inside the vessel.
The bottom of the vessel is furnished with a valve or top, used for removing the
extracted or condensed products.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Friedrich Hermann Felix Engel in the Great Seal Patent Office
on the 20th January 1882.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. "IMPROVEMENTS IN EVAPORATING VACUUM
APPARATUS." A communication from Niederberger and Co., of Hamburg, in
the German Empire.
These improved evaporating-apparatus are specially constructed and very useful
for evaporating liquids and condensing extracts or solutions to a thick and pastelike
consistency.
The improved apparatus consists of a cylindrical stationary vessel or boiler made
of copper or lined with copper if constructed of iron, which vessel is placed in a
horizontal or slightly inclined position, and receives the evaporating liquid through
a pipe communicating with the upper part of the vessel, and is filled with such
liquid to about one half or two thirds of its height.
Parallel with the horizontal axle of the cylindrical vessel, but placed below the
centre, a wrought-iron tube is passed through the vessel, and tightened by stuffing-
boxes, and this tube is lined on its outer surface with copper as far as the tube is
inside the vessel. Outside of the vessel this tube is supported by brackets, and is
at one outer end furnished with a spur wheel fastened to it, and can be brought in
rotation by another toothed wheel fastened on a shaft driven by a motor. Within
the vessel two copper plates are attached to the tube and fitted to it near the end
plates of the vessel, and between these copper plates a number of copper boiler
tubes are fastened with their ends. Each outer side of these copper plates is
enclosed in a cover or curved plate made of copper or bronze. Into one end of
the iron tube steam is admitted, and this steam passes through borings of the tube
wall into the next cover, and fills the boiler tubes with steam, which steam passes
through the heating tubes, and condenses on its way to or after having arrived at
the opposite cover, whence the condensed water is removed by a curved or bent
tube, communicating at its one end with the iron main tube of the heating
apparatus.
As the heating or boiler tubes, by revolving in the liquid or solution, stir these
latter whilst the apparatus is at work, these tubes very effectively transmit the heat
to all parts of the evaporating liquid, and are especially affective after the liquid
has arrived into a thick or pastelike state.
By means of an air-pump communicating with the upper part of the vessel or
preferably with a dome attached or formed to the top of the vessel, all steam
generated within the vessel is removed, and a vacuum kept up inside the vessel.
The end plates of the vessel may be furnished with openings covered with
toughened glass or other strong plates of a transparent nature for the purpose of
being able to observe the action of the apparatus within the vessel.
The bottom of the vessel is furnished with a valve or top, used for removing the
extracted or condensed products.
In the accompanying Sheet of Drawings is represented a construction of this
improved apparatus. Fig. 1 is a longitudinal section, Fig. 2 a cross section of
same, and Fig. 3 is a detail in sectional view of one of the parts.
The cylindrical vessel A, made of copper or lined with such metal, is filled to
about one half its height through tube b with the liquid matter that has to be
condensed.
Through the lower part of A, tube B is passed through stuffing boxes d, d, and
supported by brackets c, c, c', and this tube B is put in rotation by gearing N

page_text: from a motor. Between copper plates E, E, fastened on tube B, heating tubes r
are secured and carried, and the openings of these tubes are enclosed in cover plates
L, L'. Steam enters tube B through pipe e, and if desirable the exhaust or waste
steam of the driving engine may likewise be used for heating by communication
of tube e, in which case the high pressure steam entering through tube e will
draw in the waste steam through tube e¹. From tube B, which is closed by a
plate or slide K, the steam enters cover L through openings o, o, of the wall of the
tube B, and passes through the heating tubes 7, and by cooling off on its way
enters cover L' in a condensed state. The waste water is driven off from cover L¹
through the curved pipe m (see Figs. 1 and 3), one end of which is fustened to
tube B, whilst the other open end, during rotation of the tube B, takes up the
waste-water from L', and delivers some through the hinder end of B into standard
C of the machine frame, whence it is drawn off.
The steam generated in vessel A is evacuated by an air-pump through tube R,
fastened to dome H, that communicates with vessel A, through a perforated
plate Q, and a chimney W; this latter construction prevents any part of the boiling
liquid passing into tube R, and any such liquid will through tube T return into
vessel A.
J represent openings covered with glass or other transparent material for interior
observations, and vis a valve for drawing off the condensed liquid.
Having now described the nature of the said Invention and shown how the same
may be readily carried into practical effect, I claim,―
In an apparatus for concentration and evaporation of liquids, the rotating heating
device within the vessel A, in combination with a curved pipe m, for removing
.the condensed steam, constructed and operating as and for the purpose herein
described in reference to and as shown by the accompanying Drawings.
In witness whereof, I, the said Friedrich Hermann Felix Engel, have
hereunto set my hand and seal, this Sixteenth day of January, in the
year of our Lord One thousand eight hundred and eighty two.