IMPROVEMENTS IN DRYING WHITE LEAD AND MATERIALS IN A SIMILAR CONDITION AND IN MACHINERY EMPLOYED THEREIN, PARTS OF WHICH ARE APPLICABLE TO DRYING OTHER MATTED AND THINGS
Year: 1878

page_text: LETTERS PATENT to John Cowdery Martin, of 5, Upper Hill Street, Richmond,
in the County of Surrey, for the Invention of "IMPROVEMENTS IN DRYING
WHITE LEAD AND MATERIALS IN A SIMILAR CONDITION AND IN MACHINERY
EMPLOYED THEREIN, PARTS OF WHICH ARE APPLICABLE TO DRYING OTHER
MATTED AND THINGS"
Sealed the 3rd December 1878, and dated the 25th July 1878.
PROVISIONAL SPECIFICATION left by the said John Cowdery Martin at
the Office of the Commissioners of Patents on the 25th July 1878.
JOHN COWDERY MARTIN, of 5, Upper Hill Street, Richmond, in the County of
Surrey. *" IMPROVEMENTS IN DRYING WHITE LEAD AND MATERIALS IN A SIMILAR
CONDITION AND IN MACHINERY EMPLOYED THEREIN, PARTS OF WHICH ARE APPLI-
CABLE TO DRYING OTHER MATTERS AND THINGS."
The improvements consist,—-
Firstly. In spreading white lead or other materials in a similar pulpy condition
upon a moving endless absorbent cloth or series of cloths to be covered with a second
endless cloth or series of cloths, and these pass, the one over and between, and the
other under and between several heated cylinders, also covered with cloth revolving
within them, and so arranged that the surface of the cloths in contact with the
material to be dried shall not greatly deviate from a horizontal position in
passing from one cylinder to another after the materials have lost their pulpy con-
sistency.
Secondly. When the materials are so far dry as to become partially powdered or
granular, the drying is completed by causing them to enter the upper part of a

page_text: machine consisting of a casing heated by steam, the section across which is in the
form of the letter U, open at the top, and having within it a revolving cylinder, also
heated by steam, with several projections, some placed parallel with the axis to
carry the material round, and some placed at an angle to thrust it forward; or they
may be arranged spirally round the exterior in the manner of screw threads placed 5
at such an angle with the axis of the cylinder as to cause the material which is fed
upon the end to be lifted round within the casing as the cylinder revolves, as well
as to be thrust forward and delivered at the opposite end of the machine to which
it entered.
Other matters and things in a granular or powdered condition may be dried by 1
the machine described in the second part of my Invention.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Cowdery Martin in the Great Seal Patent Office on the 25th
January 1879.
JOHN COWDERY MARTIN, of 5, Upper Hill Street, Richmond, in the County of
Surrey. "IMPROVEMENTS IN DRYING WHITE LEAD AND MATERIALS IN A SIMILAR
CONDITION AND IN MACHINERY EMPLOYED THEREIN, PARTS OF WHICH ARE APPLI-
CABLE TO DRYING OTHER MATTERS. AND THINGS."
The improvements consist,―
Firstly. In spreading white lead or other materials in a similar pulpy condition
upon a moving endless absorbent cloth or series of cloths covered by a second
endless cloth or series of cloths, and passing, the one over and between, and the
other under and between several heated cylinders, also covered with cloth, and so
arranged that the surface of the endless cloths in contact with the material to be
dried shall not greatly deviate from a horizontal position in passing from one cylinder
to another.
Secondly. When the materials are so far dry as to become partially powdered or
granular, in completing the drying by causing the said materials to enter the upper
part of a machine consisting of a casing heated by steam, the section across which
is in the form of the letter U, open at the top, and having within it a revolving
cylinder also beated by steam, and carrying on its external surface several projec-
tions, some placed parallel with the axis to carry the material round, and some
placed at an angle to the axis in order to thrust the said material forward longi-
tudinally; or such projections may be arranged spirally round the exterior of the
revolving cylinder in the manner of screw threads placed at such an angle with the
axis of the cylinder as to cause the material which is fed upon one end thereof
to be carried round within the casing as the cylinder revolves, and also to be
thrust forward and delivered at the opposite end of the machine to that at which it
entered.
Other matters and things in a granular or powdered condition, whether subjected
previously to the operations comprising the first part of this Invention or not, may
be dried by the machine described in the second part of this Invention.
In the Drawings Figure 1 shews an arrangement for using two endless absorbent
cloths ff, in accordance with the first part of my Invention, the whole of the
heated revolving cylinders a, a¹, excepting one at each end of the machine, being by
preference covered with absorbent cloth tightly fitted over them, and which (by close
contact with the endless cloths f, f', between which the material k¹ in process of
drying is carried over and under them) absorb moisture from the material, and
become dry as the cylinders revolve.
• Sometimes to facilitate the absorbtion I press the cloths f, f, containing between
them the material to be dried, against the cylinders a, a', by means of pressure
rollers b, b', placed alternately above and below each endless cloth and between the
heated cylinders a, a¹, the upper rollers b, b, pressing downwards on the cloth by
their own weight, and the lower rollers b¹, 61, being caused to press upwards by
means of levers, springs, or other suitable means, each roller being caused to revolve
merely by contact with the moving cloths and cylinders.
The drying cylinders a, a', are arranged so that the lowest parts of the peripheries
of the upper series under which the endless cloths f, f., pass shall not be more than a
few inches below the highest parts of the peripheries of the lower cylinders, in order
that the angle formed by the cloth in rising or descending from one cylinder to
another may be so slight as to allow the material between the cloths to pass forwards
without falling back.
Figure 2 shews an arrangement by which the cloths with the material in process
of drying may be maintained in a perfectly horizontal position, and also that,
instead of covering each cylinder separately with absorbent cloth, an endless

page_text: absorbent cloth g or g¹ may be passed round them, and caused to work within each
of the two outer cloths.
Sometimes when using this arrangement I do not heat the cylinders marked c, c¹;
at the feeding end of the machine which are in contact with the parts of the cloths
next the material in process of drying.
The lower endless cloths f¹, f, are extended, as shewn at f², Figures 1, 2, and 3,
forming a flat surface or table supported by means of small rollers f³, f³, or in any
other convenient manner, and the material to be dried is thinly spread upon this
flat moving surface by passing it from the hopper k between the pair of rollers d
and d¹, which extend across the width of the machine, and to which rollers the
material adheres, and is carried round and removed by a narrow scraper e fixed
against the lower part of the feed roll d, whence it falls on to the cloth beneath and
is carried between the drying cylinders a, a', in Figures 1 and 3, or c, c', in Figure 2,
the first pair of which in Figure 1; and the several pairs of cylinders marked c, c¹,
in Figure 2, are placed sufficiently close together to exert pressure upon and further
spread it.
Figure 3 shews an enlarged section of the feed rolls, with the position of scraper
and cloth beneath.
Similar letters refer to like parts in all the Figures 1; 2; and 3.
When steam is used for heating the revolving cylinders, they are fitted with the
means usually employed in cylinder drying machines for discharging the condensed
water and preventing the escape of the steam, and the various moving parts of the
machine are driven by the usual gearing, or in any other convenient manner.
I have found that the cloths in passing between the cylinders a, a, b, b¹, and c, c¹;
(see Figures 1, 2, and 3) sometimes become creased and do not run evenly; I correct
this, and keep then flat on returning to the feed end of the machine by means of
two pairs of small rollers or wheels B, B, (see Figures 4 and 5) working at an angle
with the direction in which the cloths are travelling, and placed at opposite edges of
each of the moving cloths, such wheels being cut away or flattened at one or more
parts B', B, of their circumferences, and so arranged that the said flat parts of each
pair work opposite each other as they revolve, and the cloth is thereby alternately
stretched by the round parts, and released as the flat parts come opposite each
other. By this means the pair of rolls on one edge of the cloth pulls against the
pair on the opposite edge, thereby extending the cloth and removing the creases:
These rollers may be geared together, as shewn in Figure 4, so as to revolve
synchronously.
If preferred, other means may be employed for removing the creases from the
cloths.
The drying cylinders c and c¹ (Figures 1, 2, and 3) may be either covered with
absorbent cloth or felt tightly fitted over them, or covered by a second endless
cloth working within the outer one, carrying the material to be dried, as herein-
before described; or the drying may be effected, although less rapidly, by using the
outer cloths only, the cylinders being not otherwise covered with cloth.
When the machine, as above described, is from thirty to thirty-five feet long, and
is driven at a speed such that the material occupies from forty-five to sixty minutes
in passing between the cylinders, the moisture is readily extracted to within from
three to five per cent., and if the length of the machine is sufficiently extended, this
may be entirely removed; but to avoid using excessively long machines, I prefer
to finish the drying by passing the material over the surface of a sufficiently strong
drying cylinder b (see Figures 6 and 7), heated by steam or otherwise, and fitted
with the usual means for removing condensed water, and working within a steam
or otherwise heated casing a, a.
.
The cylinder b is fitted with projecting strips or screw threads e; e, preferably of
metal, the angle of which may vary according to the description of material intended
to be dried, and the speed at which the machine is driven. I have found the angle
formed by a turn of from a quarter to half the circumference of the cylinder in a
length of five diameters gives good results, but any other form or description of

page_text: projections that will carry the material round the cylinder as well as thrust it
forward may be used.
The first part of my Invention, although specially applicable to the drying of
white lead, is also applicable more or less to the drying of all substances or materials
from which moisture can be extracted by absorption.
The second part of my Invention is also applicable more or less to the drying of
all substances in a granular or powdery condition.
Instead of heating both the cylinder and the casing, the cylinder only or the casing
only may be heated.
Although I have described endless absorbent cloths, I do not confine myself to
them, as it will be evident that similar effects may be produced by employing cloths
of definite lengths and causing them to travel alternately forwards and backwards,
the feeding apparatus being arranged accordingly; and instead of passing the
absorbent cloths over cylindrical heated surfaces, they may be caused to pass over
heated surfaces of other form.
Having now described the nature of my said Invention, and the manner in
which the same is to or may be performed, I would have it understood that what I
claim is,
Firstly. Drying white lead or other materials in a pulpy or pasty condition by
spreading it or them upon or between moving absorbent cloth or cloths, which takes
or take up the moisture therefrom, then removing the said moisture from such
absorbent cloth or cloths by passing the same over, around, or between heated
cylinders covered or not with other absorbent cloth, substantially as herein-before
described.
Secondly. The use of absorbent cloths combined with heated cylinders or other
heated surfaces for drying materials capable of parting with moisture by absorption,
substantially as herein-before described.
Thirdly. The general arrangement and adaptation of heated cylinders in com-
bination with absorbent cloths, applied and operated substantially as herein-before
described, and illustrated in Figures 1, 2, and 3 of the Drawing, and for the purposes
set forth.
Fourthly. The arrangement of the absorbent cloths so as to be conducted between
the cylinders in a nearly horizontal position, substantially as herein-before described,
and illustrated in Figures 1, 2, and 3 of the Drawing, and for the purpose set
forth.
Fifthly. Covering the cylinders with absorbent cloth or its equivalent, sub-
stantially as and for the purpose described.
Sixthly. The combination of the cylinder having external projections or screw
threads with an external casing, either or both of which may be heated, substantially
as herein-before described, and illustrated in Figures 6 and 7, and for the purpose
set forth.
Seventhly. The application and use of the tension rollers B, B, shewn in Figures
4 and 5 of the Drawings, constructed with flat or straight portions, and geared
together so as to revolve synchronously, as herein-before described, and for the
purpose set forth.
In witness whereof, I, the said John Cowdery Martin, have hereunto set my
hand and seal, this Twenty-fourth day of January, in the year of our Lord
wht hundaad and anvender nine