AN IMPROVED APPARATUS FOR DRYING SEWAGE PRECIPITATES, CEMENT, PAPER PULP, AND OTHER FLUID OR SEMI-FLUID MATTERS
Year: 1872

page_text: LETTERS PATENT to William Hart and James Hart, both of Crossness,
in the County of Kent, Engineers, for the Invention of "AN IMPROVED
APPARATUS FOR DRYING SEWAGE PRECIPITATES, CEMENT, PAPER PULP, AND
OTHER FLUID OR SEMI-FLUID MATTERS."
Scaled the 18th March 1873, and dated the 9th December 1872.
PROVISIONAL SPECIFICATION left by the said William Hart and
James Hart at the Office of the Commissioners of Patents, with
their Petition, on the 9th December 1872.
We, WILLIAM HART and JAMES HART, both of Crossness, in the
County of Kent, Engineers, do hereby declare the nature of the said
Invention for "AN IMPROVED APPARATUS FOR DRYING SEWAGE PRECIPITATES,
CEMENT, PAPER PULP, AND OTHER FLUID OR SEMI-FLUID MATTERS," to be as
follows:-
Our Invention has for its object the drying of sewage precipitates, or
sewage mud, paper pulp, peat, and other fluid or semi-fluid matters, and
consists essentially of a revolving drum (the cylindrical part of which is
perforated or reticulated), and other apparatus in connection therewith,
such drum and apparatus being arranged as herein-after described, so as

page_text: to separate the water from the matter to be dried, and draw a coating of
such matter on to the periphery of the drum, then to draw hot or dry air
through such coating, and thereby dry it; and then to force cold air
through the dried matter, and thereby detach it from the drum.
The said drum consists of two discs mounted at a suitable distance
apart upon a horizontal shaft, wire gauze or other straining medium
being affixed to the edges of the said discs so as to constitute a series of
strainers. The lower part of the drum works in a tank containing the
matter to be dried. The upper part (except at the part where the dried
matter is detached) is covered by a hot air casing, into which hot air
from a furnace or air heater is introduced by means of a pipe leading
from the said furnace or heater to a longitudinal trough affixed to the
said casing. The drum is divided by means of curved metal plates into
a series of longitudinal chambers which communicate by means of bent
pipes with ports formed in a cylinder keyed on the drum shaft and
outside the drum. This cylinder revolves in a stationary outer cylinder,
which is of such diameter as to leave an annular space between the two
cylinders. At the ends of the outer cylinder are stuffing boxes in
which the inner cylinder works air tight. The said annular space is
divided by means of packed ribs into three chambers, which I term
respectively the water exhaust chamber, the hot air exhaust chamber,
and the blast chamber.
.
The water exhaust chamber communicates by means of a pipe with
a suction pump which draws the water through those of the longitudinal
chambers aforesaid, which are immersed in the matter to be dried, and
in so doing causes a coating of such matter to adhere to the periphery of
the drum. The water thus drawn into the chamber is drawn therefrom
through the pipes and ports which communicate with the cold water
exhaust chamber.
The hot air exhaust chamber communicates by means of a pipe with a
suction pump which draws hot air through those of the longitudinal
chambers which are passing under the hot air casing herein-before
referred to, and thereby dries the coating of mud or other matter
adhering to the periphery of the drum. The vapour giving off by the said
mud or matter is passed into a condenser.
The hot air induction pipe is furnished with a throttle valve for
cutting off the hot air when the apparatus is stopped, and the hot air

page_text: casing is furnished with inlet and outlet valves so arranged as to admit a
draught of cold air through the said casing to cool the parts when it is
necessary to handle them. The blast chamber communicates by means
of a pipe with a forcing pump which forces air through the longitudinal
chamber in communication with the said blast chamber, which air tends
to loosen or detach the dried mud or matter from the periphery of the
drum. A brush or scraper is mounted at this part of the drum to
complete the removal of the said mud or matter.
The hot air may be forced through the longitudinal chambers aforesaid,
by a pump or fan in which case the hot air exhaust pump may be
dispensed with.
As the drum revolves its chambers are successively brought into com-
munication with the water exhaust chamber, the hot air exhaust chamber
and the blast chamber, so that while the water is being strained off from
the mud at the lower part of the periphery of the said drum the mud
is being dried upon and detached from the upper part as herein -before
described.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Hart and James Hart in the Great Scal
Patent Office on the 9th June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM.
HART and JAMES HART, both of Crossness, in the County of Kent,
Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of December, in the year of our
Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said William Hart and James Hart, Her
special license that we, the said William Hart and James Hart,
our executors, administrators, and assigns, or such others as we, the
the said William Hart and James Hart our executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,

page_text: and Isle of Man, an Invention for "AN IMPROVED APPARATUS FOR DRYING
SEWAGE PRECIPITATES, CEMENT, PAPER PULP, AND OTHER FLUID OR SEMI-FLUID
MATTERS," upon the condition (amongst others) that we, the said William
Hart and James Hart, our executors or administrators, by an instrument
in writing under our or their hands and seals, or under the hand and
seal of one of us or them, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said William Hart, on behalf of
myself, and the said James Hart, do hereby declare the nature of
the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following
statement thereof, that is to say :—
Our Invention has for its object the drying of sewage precipitates or
sewage mud, paper pulp, peat, and other fluid or semi-fluid matters, and
consists essentially of a revolving drum (the cylindrical part of which is
perforated or reticulated) and other apparatus in connection therewith,
such drum and apparatus being arranged, as herein-after described, so as
to separate the water from the matter to be dried, and draw a coating of
such matter on to the periphery of the drum, then to draw hot or dry
cold air through such coating, and thereby dry it, and then to force cold
air through the dried matter, and thereby detach it from the drum.
The said drum consists of two discs mounted at a suitable distance
apart upon a horizontal shaft, wire gauze or other straining medium
being affixed to the edges of the said discs so as to constitute a series of
strainers. The lower part of the drum works in a tank containing the
matter to be dried. The upper part (except at the part where the dried
matter is detached) is or may be covered by a hot air casing, into which
hot air from a furnace or air heater is introduced by means of a pipe
leading from the said furnace or air heater; or, cold dry atmospheric air
may be used, in which case the aforesaid casing is dispensed with. The
drum is divided by means of curved metal plates into a series of longi-
tudinal chambers which communicate by means of bent pipes with ports
formed in a cylinder keyed on the drum shaft and outside the drum.
This cylinder revolves in a stationary outer cylinder, which is of such
diameter as to leave an annular space between the two cylinders. At

page_text: the ends of the outer cylinder are stuffing boxes in which the inner
cylinder works air-tight. The said annular space is divided by means of
packed ribs into three chambers, which we term respectively the water
exhaust chamber, the air exhaust chamber, and the blast chamber.
The water exhaust chamber communicates by means of a pipe with
a suction pump which draws the water through those of the longitudinal
chambers aforesaid, which are immersed in the matter to be dried, and
in so doing causes a coating of such matter to adhere to the periphery of
the drum. The water thus drawn into the chambers is drawn therefrom
through the pipes and ports which communicate with the cold water
exhaust chamber.
The air exhaust chamber communicates by means of a pipe with a
suction pump which draws hot air through those of the longitudinal
chambers which are passing under the hot air casing herein-before
referred to, or which are open to the atmosphere, as the case may be,
and thereby dries the coating of mud or other matter adhering to the
periphery of the drum.
The hot air induction pipe is furnished with a throttle valve for cutting
off the hot air when the apparatus is stopped, and the hot air casing is
furnished with inlet and outlet valves so arranged as to admit a draught
of cold air through the said casing to temper the heat when necessary.
The blast chamber communicates by means of a pipe with a forcing
pump which forces air through the longitudinal chamber in communi-
cation with the said blast chamber, which air tends to loosen or detach
the dried mud or matter from the periphery of the drum. A brush
or scraper, or both, is or are mounted at this part of the drum to
complete the removal of the said mud or matter; or the dried matter
(such as paper pulp) may be removed by a roller instead of by the
scraper and brush referred to.
The hot or cold air may be forced through the longitudinal chambers
aforesaid by a pump or fan, in which case the air exhaust pump may be

page_text: said drum, the mud or other matter is being dried upon and detached
from the upper part, as herein-before described.
Having now described the nature of our Invention, we will proceed to
describe the manner in which the same is to be performed, reference
being had to the accompanying Drawings, and to the letters and figures
marked thereon.
The same letters and figures of reference indicate the same parts in all
the Figures.
Figures 1 and 2 are elevations taken at right angles to one another of
our said apparatus; Figure 3 is a vertical section taken on the line 1, 2,
Figure 2; Figure 4 is a vertical section taken on the line 3,4, Figure 1;
and Figure 5 is a transverse section of the cylinders D and E herein-
after referred to, the said section being taken on the line 5, 6, Figure 2.
A is a shaft on which are mounted two discs B¹, B³, to tho edges of
which or to ribs 61, 61, secured thereto, wire gauze or other straining
medium 6ª is affixed so as to form a drum, which is divided into a series
of shallow longitudinal chambers 68, 6³, by means of curved metal
plates 6, 6, bent at 6, 6, so as to form longitudinal partitions at
those parts, 6º, 6º, are ribs bolted to or cast on the plates *, *, which ribs
support the wire gauze 62, and to them when necessary the said gauze
may be screwed or otherwise fastened. 67, 67, are tapered fillets of wood
set in the angles formed by the turned up portions 65, 6, of the
plates b*, 6, (see Figure 3), to conduct the water to the cups c¹, c¹ ;
68, 68, are strips of india-rubber placed between the edges of the
said plates and the wire gauze to make the joints air-tight. The
chambers 63, 63, communicate by means of pipes C, C, connected to the
cups c¹, c¹, with ports d³, d¹, formed in a cylinder D keyed to the shaft A
and bolted to the disc B². The cylinder D revolves within a stationary
cylinder E, the ends of which are provided with stuffing boxes e¹, e¹, and
glands e, e². The space between the cylinders D and E is divided by
means of grooved ribs e³, e³, (see Figure 5), packed with strips of india-
rubber e, e, into the water exhaust chamber e³, the air exhaust
chamber e, and the blast chamber e'. The chambers e and e com-
municate by means of pipes e³, e, with suction pumps (not shown) and
the chamber e' communicates by means of the pipe e¹ with a forcing a
pump (not shewn). The cylinder E is prevented from turning by the
flange e", which is bolted to a bracket g¹ affixed to the beam g². The

page_text: shaft A and cylinder D are supported by and work in bearings F, F,
affixed to the beams 92, 92, mounted on the sides of a tank G in which
the lower part of the drum works. g³ is an inlet pipe through which
the matter to be treated enters the tank; H is a casing mounted over
the said drum and supported by rods h³, h³, and brackets h³, h³, bolted to
the beams g², g²; h³, h³, are flanges of india-rubber, by means of which
and a hinged flap hair is prevented from entering the said casing at
the sides and the upper part thereof; /* is a pipe leading from a furnace
or air heater (not shewn), by which hot air may be conducted to the
said casing; he is an escape pipe; h³, h³, hº, are valves by which
communication with the heated air or the external atmosphere may
be opened or closed as required; " is a hinged flap faced with india-
rubber, for spreading evenly on the drum the matter to be dried; I is
a rotatory brush mounted in brackets i bolted to the tank G; 9' is a
hinged flap to which a strip of india-rubber g' is secured for removing
the dried matter from the drum; g is one of two strips of india-rubber
affixed to the beams g³, 9², which strips pressing against the sides of the
drum remove the moist matter therefrom as the said drum revolves and
keep them clean. The drum is or may be caused to revolve by a band
passing over pulleys (not shown) mounted on the shaft A, from which
shaft the necessary rotatory motion for the brush I may be obtained.
The arrows shew the directions in which the drum and brush revolve.
For drying paper pulp we stretch over the wire gauze around the
drum canvass, flannel, or other suitable straining medium, and we
substitute for the removing brush herein-before described a roller, which
receives the pulp as detached and deposits it on a travelling web.
The action of the apparatus is as follows:-The matter to be dried
being run into the tank G the drum is caused to revolve, the suction
pump draws the water through those of the longitudinal chambers *, *,
which are immersed in the matter to be dried, and in so doing causes a
coating of such matter to adhere to the wire gauze b³, or to the straining
medium with which it may be covered. The water thus drawn into the
said chambers is drawn therefrom through those of the pipes C and
ports d', d, which communicate with the water exhaust chamber e³.
When the said chambers are brought by the revolution of the drum into
communication with the air exhaust chamber eº, that portion of the
periphery of the drum on to which the said coating of matter has been

page_text: drawn is being carried under the air casing H, and hot air is drawn
through the said matter, which is thereby dried. The further revolution
of the drum carries the dried matter from under the casing and brings
the aforesaid chambers into communication with the blast chamber e³.
The said matter is then loosened by the blast from the forcing pump and
completely removed by the brush I and scraper g³, or by the said scraper
and the roller herein-before referred to.
Instead of drawing hot air through the coating of wet matter, cold
dry air may be used when the casing H may be dispensed with.
Having now described the nature of our Invention, and the manner
in which the same is to be performed, we wish it to be understood that
we do not limit ourselves to the precise details herein described, as the
same may be varied without departing from the nature of our Invention;
but we claim as our said Invention, the improved apparatus herein-
before described and illustrated in the accompanying Drawings, for
drying sewage precipitates, cement, paper pulp, and other fluid or
semi-fluid matters, that is to say, a revolving drum, the periphery of
which is formed of wire gauze or other straining medium, the interior
of the said drum being divided into chambers which are successively
brought by the revolution of the drum into communication with suction
and forcing pumps, so that the matter being treated is continuously
drawn on to the said drum, dried, and removed therefrom at different
portions of its periphery, essentially as described.
In witness whereof, I, the said William Hart, have hereunto set my
hand and seal, this Ninth day of June in the year of our Lord
One thousand eight hundred and seventy-three.
Witness,
B. WILLCOX,
Clerk to H. H. Murdoch,
7, Staple Inn,
London.
WILLIAM HART. (L.S.)