IMPROVEMENTS IN DESICCATING OR DRYING SEWAGE AND OTHER MATTERS; AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1882

page_text: "
LETTERS PATENT to John Henry Johnson of 47 Lincoln's Inn Fields in the
County of Middlesex Gentleman-for an Invention of IMPROVEMENTS IN
DESICCATING OR DRYING SEWAGE AND OTHER MATTERS; AND IN THE
APPARATUS EMPLOYED THEREIN A communication from abroad by Edmond
DL: S
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 23rd February 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman " IMPROVEMENTS IN DESCCATING OR DRYING SEWAGE AND OTHER
MATTERS AND IN THE APPARATUS EMPLOYED THEREIN A communication from
abroad by Edmond Coignet of Paris in the Republic of France Civil Engineer.
33
This Invention has for its object to provide apparatus suitable for drying or
desiccating by the employment of the heat of steam under pressure whereby it is
rendered possible to concentrate a great amount of heat in a given space
The said Invention relates to a class of apparatus known as Firman's drying
apparatus and has for its object to render such apparatus suitable for drying or
desiccating very watery matter such as the solid products of sewage or materials of
the like kind :-
The apparatus constructed for this purpose according to this Invention is designed
to present very large heating surface in proportion to the volume of the matter to
be desiccated to give a considerable difference in temperature between the mass
desiccated and the steam employed for heating and to provide for the absence of
any intermediate body other than the casing which will oppose the passage of
the heat:
The drying cylinder is provided with double or hollow ends and sides and is
capable of revolution. At each revolution of this cylinder the hottest steam being
at the upper side heats the inner wall to its maximum degree and the water of
condensation upon this side is also discharged at the same time

page_text: The continued rotation of the cylinder continually brings the matter which it
contains into contact with the hottest part of the side thus complying with an
essential condition of efficiency. Moreover the contents are by this rotation
effectually stirred up, constantly bringing fresh surfaces into contact with the
heated side. The shaft on which the cylinder rotates is also capable of rotation
but in an opposite direction from that of the cylinder and steam is introduced into
the cylinder and into the shaft and means are provided for purging the cylinder
and shaft of water of condensation and for removing the gas and vapour or bye
products. These operations are performed at the centre on which the cylinder and
shaft rotate.
The various parts of the apparatus perform the following functions viz:
Distributing the steam as a heating medium-Exhausting and Drawing off the
volatile products of evaporation-Discharging the water of condensation-Stirring
or agitating the matter under treatment mechanical arrangements being provided
for obtaining a maximum effect. Transmitting motion so as to actuate both the
cylinder and the shaft or the one or the other alone:
The steam enters the hollow shaft through a tube opening thereinto and from
this shaft it is conducted into the interior of hollow discs mounted on and in
communication with the interior of the shaft pipes forming communications between
the outward parts of the said discs. From the said shaft the steam also passes into
the hollow sides and ends of the cylinder through passages in the end of the cylinder
and thus heats the mass under treatment at the circumference as well as at the
centre.
The cylinder is surrounded by a casing enclosing an air space for the purpose of
preventing loss of heat by radiation:
In order to increase the amount of heating surface and prevent the material
from adhering to the sides of the cylinder the aforesaid discs are provided with
scrapers:
The matter under treatment contained in the cylinder becomes rapidly dried
under the action of the heat and the rotation of the shaft and cylinder the vapours
and noxious gases being drawn off by a suction apparatus such as a fa or an air
pump. The pressure being thus lowered in the interior of the cylinder the boiling
point of the liquid matter is lowered and consequently the difference between the
temperatures of the drying medium and the matter being dried is increased.
The vapours are drawn from the cylinder at the centre and are condensed either
in a surface condenser or in a condenser in which cold water is injected.
These vapours may be utilized in certain cases for evaporating liquids in a vessel
or series of vessels in which a greater degree of vacuum is produced than in the
cylinder. The vapours which escape condensation are mixed with air and con-
sumed in a furnace. If preferred the vapours may either before or after passing
through the condenser, be submitted to treatment by any suitable chemical or
other process in order to change the character of the gases and dispel their odour.
The discs aforesaid by supporting the tubes and scrapers prevent the straining
and loosening of the joints. The revolving cylinder is supported at each end upon
rollers.
The aforesaid discs are formed in segments of separate compartments communi-
cating with the hollow shaft by short pipes projecting thereinto for the discharge
of water of condensation and the prevention of its return:
The water of condensation collecting in the hollow sides of cylinder is caused to
flow into the hollow shaft through the passages for the admission of steam by
means of blades or guide plates arranged in the end of the cylinder the said
passages being provided with a lip or rim projecting into the interior of the shaft
to prevent the water from returning, a syphon is provided for drawing off the
water of condensation which collects in the interior of the hollow shaft, One leg of
this syphon is carried through a stuffing box at one end of the said shaft and
through another stuffing box or boxes at the outer extremity of a continuation of
the hollow shaft separate from the steam space thereof to outside the apparatus.

page_text: The said water may be drawn off continuously by prolonging the steam space of
the shaft to its end.
•
In order to afford a ready means of causing either the cylinder or the shaft to
rotate alone or together in opposite directions or to throw both out of action a
driving shaft is employed carrying a pinion gearing with a wheel on or connected
to the cylinder A clutch arrangement is capable of being slidden on the hollow
shaft to cause the motion of the cylinder to be communicated by a planetary
wheel arrangement to the said hollow shaft but in the reverse direction to that
of the said cylinder, To rotate the hollow shaft without the cylinder the gear
which drives the cylinder is thrown out of gear; another pinion on the driving
shaft being simultaneously brought into position to drive a toothed wheel keyed
to the hollow shaft. These different movements of the gear may all be effected by
a lover having a fulcrum at about its centre its lower end being operated by a
screw to bring it ino the various positions necessary to cause it to move and retain
the gear in the aforesaid relative positions.
The doors for discharging the contents of the apparatus are arranged to close
water and steam tight against the sides of the cylinder forming when closed a
part thereof and being capable of being readily opened for the discharge of the
dried matter.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
23rd August 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN DESICCATING OR DRYING SEWAGE AND OTHER
MATTERS AND IN THE APPARATUS EMPLOYED THEREIN A communication from
abroad by Edmond Coignet of Paris in the Republic of France.
"3
This Invention has for its object to provide apparatus suitable for drying or
desiccating by the employment of steam under pressure in the manner hereinafter
described whereby the heat is concentrated and enabled to act under more
favorable conditions than in apparatus of ordinary construction.
The said Invention relates to a class of apparatus known as Firman's drying
apparatus and consists in certain improvements in the construction and arrange-
ment of the parts whereby such apparatus is rendered suitable for drying sewage
or other very watery matter.
In the treatment of putrescible and infectious matter such as foul water animal
and vegetable refuse night soil sewage and the like it is of importance to be able
to dry a large quantity of matter in a short period of time In order to comply
with these conditions hot air has been employed as the heating agent but as it is
only necessary to desiccate the materials but is also absolutely indispensable to
disinfect the products of dessication the employment of air involves the subjection
of an enormous quantity of air to a costly disinfecting process.
The improved apparatus constructed according to this Invention is designed to
present a very large heating surface in proportion to the volume of the matter
to be desiccated to give a considerable difference in temperature between the mass
to be desiccated and the steam employed for heating and to dispense with all
intermediate bodies other than the casing to oppose the passage of the heat.
The apparatus known as Firman's apparatus as constructed is composed
essentially of a stationary cylinder with a heated double casing traversed by an
internal inovable shaft carrying tubes and scrapers.
The proportion or difference between the heating surface and the volume of the
mass is too small to enable this apparatus to accomplish the results attainable by
means of the present Invention. The hottest steam passes to the upper part of the
double casing and the material under treatment which occupies the lower part is
brought into contact with the side which is least heated moreover the condensation
of the steam within the double casing produces a constant flow of water over the
inner wall of sheet metal which greatly impedes the heating of the said wall and
the transmission of the heat.
These defects render Firman's machine incapable of being employed with
advantage for the desiccation of very watery matter and the solid products of night
soil in particular.
In the improved apparatus constructed according to this Invention the heating
surface is increased by the employment of double or hollow ends and a series of
plates carried by the shaft and heated. The drying cylinder is provided_with
double or hollow ends and is capable of revolution. At each revolution of this
cylinder the hottest steam being at the upper side heats the inner wall to its
maximum degree and the water of condensation upon this side is also discharged
at the same time by a special arrangement hereinafter described.
The rotation of the cylinder effectually stirs up the contents and continually

page_text: brings fresh parts of the matter which it contains into contact with the hottest
part of the sides thus complying with an essential condition of efficiency.
The shaft on which the cylinder rotates is also capable of rotation but in an
opposite direction from that of the 'cylinder and steam is introduced into the
cylinder and into the shaft means being provided for purging the cylinder and
shaft of water of condensation and for removing the gas or vapours. These
operations are performed at the centre on which the cylinder and shaft rotate.
No other combination of movements can produce the same effect if the shaft
were stationary for example and the cylinder moveable the same disadvantages
would present themselves as regards the heating of the shaft and plates as in the
case of a stationary cylinder. Moreover the working of the cylinder would become
impossible as the matter would continually accumulate against the stirrers and
scrapers.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheets of drawings the same letters of reference
indicating corresponding parts in all the figures.
Figure 1 sheet 1 of the accompanying drawings is a longitudinal section taken
through the axis of an apparatus constructed according to this Invention showing
the general arrangement of the parts.
Figure 2 is a transverse section taken along the line 3, 4, 5, 6, figure 1.
Figure 3 is a section taken along the line 1, 2 figure 1 showing the construction
of the clutch lever hereinafter described.
Figure 4 is a transverse section taken along the line 7, 8, figure 1.
Figure 5 is a detail plan of a roller box hereinafter described.
Figure 6 is a transverse section taken along the line 9, 10 figure 1,
Figure 7 Sheet 2 is a modification of the driving gear in which the shaft is
prolonged through the end of the cylinder and is surrounded by a sleeve for the
exhaust
Figures 8, 9, and 10 illustrate modifications of the driving mechanism as herein-
after described,
The vertical lines or hatching represent the hot air chamber and the horizontal
lines or hatching represent the space in which the steam employed for heating is
caused to circulate.
The various parts of the apparatus perform the following functions videlicet
Distributing the steam as a heating medium, exhausting and drawing off the
volatile products of evaporation, discharging the water of condensation stirring or
agitating the matter under treatment mechanical arrangements being provided for
obtaining a maximum effect and transmitting motion so as to actuate both the
cylinder and the shaft or the one or the other alone.
The steam enters the apparatus through a tube a in the direction indicated by
the arrow and passes into a central chamber or hollow shaft A, A², whence it is
conducted through the interior of hollow discs B to pipes 6 figuro 1 & 4.
From the central chamber or hollow shaft A, A, the steam likewise passes
into the hollow sides and ends of a cylinder or casing C through passages c
and thus heats the mass under treatment at the circumference as well as at the
centre.
The cylinder is surrounded by a casing enclosing an air space for the purpose
of preventing loss of heat by radiation.
In order to increase the amount of heating surface and prevent the material
from adhering to the sides of the cylinder the discs B are provided with
scrapers r
The course followed by the steam in all the parts serving for the distribution of
the caloric is clearly shown in the drawing by means of arrows
The matter under treatment contained in the cylinder becomes rapidly dried
under the action of the heat and the rotation of the shaft and cylinder the vapours

page_text: and noxious gases are drawn off by a suction apparatus such as a fan or an air
pump. The pressure being thus covered in the interior of the cylinder the boiling
point of the liquid matter is lowered and consequently the difference between the
temperatures of the drying medium and the matter being dried is increased
The vapours are drawn from the cylinder at the centre and are condensed
either in a surface condenser or in a condenser in which cold water is injected.
These vapours may be utilised in certain cases for evaporating liquids in a vessel
or series of vessels in which a greater degree of vacuum is produced than in the
cylinder. The vapours which escape condensation are mixed with air and con-
sumed in a furnace If preferred the vapours may either before or after passing
through the condenser be submitted to treatment by any suitable chemical or
other process in order to change the charactor of their gases and dispel their
odour.
In the apparatus heretofore employed the tubes are exposed to strains which
shake and loosen them producing leakage and injury necessitating expensive 1
repairs but in this improved apparatus this defect is avoided by the employment
of the discs B which afford a firm support for the tubes and scrapers.
The roller box illustrated in Figures 4. 5 and 7 serves to support the revolving
cylinder at each end and enables the said cylinder to turn with a smooth and
regular motion at the same time lessening the strain upon the shaft and bearings.
The internal arrangement of the shaft also presents two special features The
steam is conducted from the hollow shaft to the hollow sides of the cylinder by
the three passages c leakage being prevented at these points by means of two
stuffing boxes pp' which are capable of being screwed up from the outside.
The discharge of the water of condensation collecting in the discs B which are
constructed in segments will be readily understood by referring to Figure 6 the
escape of the said water being provided for by means of short pipes projecting a
short distance into the shaft so as to prevent the water from flowing back into
the disc.
The water of condensation collecting in the hollow sides of the cylinder is
caused to flow into the hollow shaft through the passages for the admission of
steam by means of blades or guide plates arranged in the end of the cylinder the
said passages being provided with a lip or rim projecting into the interior of the
shaft to prevent the water from returning.
At one extremity of the apparatus a syphon d is provided for drawing off the
water of condensation from the shaft A One leg of this syphon is carried through
a division e at one end of the shaft and through stuffing boxes c¹ at the outer
extremity of the hollow shaft where the other leg of the syphon discharges the
water outside the apparatus This arrangement for drawing off the water inter-
mittently will be readily understood by referring to Figures 1 and 6.
The arrangement illustrated in Figure 7 presents the advantage of drawing off
the water continuously by prolonging the steam spaces of the shaft to its end and
providing an annular chamber for the passage of the gases. In this arrangement
the syphon d is stationary being supported by the revolving collar b placed
between two rings fixed to the tube or syphon,
Motion is communicated to both the shaft A fig 1 and the cylinder C by a drum or
pulley E and the notions of the several parts are obtained by working a single
fever F connected to a clutch or disengaging gear This lever has its fulcrum at a
fixed point fand is worked by means of an endless screw G The extremity g of
the lever F is connected with a friction clutch H on the shaft A.
A spur wheel K is driven by a pinion L when the parts are in the position
shewn in the drawing By shifting the clutch lover F a pinion M is also enabled
to drive a wheel N (fast on the shaft A) by the intervention of a spur wheel
indicated by a dotted circle M' in Figure 2 A piniou I partaking of a planetary
motion with regard to the wheel K causes the shaft A to rotate in an opposite
direction to the cylinder when the friction clutch H is in gear

page_text: The foregoing description of the mechanism for transmitting the motion with
reference to Figures 1 and 2 is sufficient to explain the action of the apparatus
The drawing represents the apparatus (cylinder and shaft) as being ready to work
A slight displacement of the lever to the right suffices to disengage the friction
clutch and cause the cylinder to rotate alone by moving the lever still farther in
the same direction all the parts of the apparatus will be thrown out of gear and
when the lever is pushed over to the end of its stroke in the same direction the
shaft alone will rotate. These different positions are indicated by dotted lines in
the drawing.
When the lever is in the position marked a the cylinder and the shaft both
rotate.
When the lever is in the position marked a¹ the cylinder alone rotates.
When the lever is in the position marked a¹¹ the apparatus is entirely at rest.
When the lever is in the position marked a the shaft rotates alone
This mechanism for imparting motion to the apparatus may also be arranged
according to the modifications illustrated in Figures 7, 8, 9 and 10 sheet 2.
According to all the arrangements illustrated in these figures the single lever F is
employed and acts in a similar manner to the lever in the arrangement herein before
described but the wheel M and pinion N are dispensed with the spur wheel K
carrying the planet wheel is keyed to the shaft and the ond of the cylinder is
provided with two toothed wheels G.
In the case of these arrangements the parts perform the same functions as those
described with reference to Figure 1 and are also combined in such a manner as to
cause the cylinder and shaft to rotate in opposite directions.
These arrangements are designed to comply with certain conditions of working
for example the order of succession of the different combinations of movements
instead of taking place in the order described in connection with the first
arrangement is arranged as follows videlicit
When the lever is in the position marked a the cylinder and shaft rotate
simultaneously.
When the lever is in the position marked a¹ the shaft rotates alone.
When the lever is in the position marked all the whole of the apparatus is at
rest.
When the lever is in the position marked all the cylinder alone rotates.
It will thus be seen that by employing either of the herein before described
arrangements the attendant is enabled by means of the very simple action of the
lever to impart to the several parts of the apparatus either separately or simul-
taneously all the motions which are necessary in order to expose the matter under
treatment to the most completo desiccation possible in the shortest possible time.
The doors for charging and discharging the contents of the cylinder may be
arranged as shewn in Figure 1 or preferably as shown in Figure 7 so as to render
the internal stuffing boxes readily accessible in the latter case the bearing or
friction rollers are arranged closer together near the centre of the apparatus.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is.
First The improvements in desiccating or drying sewage or other matter
consisting in treating it in apparatus constructed substantially as hereinbefore
described.
Second The general arrangement and combination of parts constituting the
apparatus for desiccating or drying sewage or other matter substantially as herein-
before described and illustrated in the accompanying drawings.
Third-The employment in combination with desiccating or drying apparatus of
mechanism for imparting motion to different parts of the same together or separately

page_text: substantially as described and illustrated in the accompanying drawings under
various modifications.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this first day of August One
thousand eight hundred and eighty two.
I HENRY JOHNSON.
(L.S.)