A New or Improved Apparatus for Drying White Lead or other Material.
Year: 1894

page_text: Date of Application, 29th Jan., 1894
Complete Specification Left, 26th Oct., 1894-Accepted, 1st Dec.. 1894
PROVISIONAL SPECIFICATION.
A New or Improved Apparatus for Drying White Lead or other
Material.
I, OSWALD HAMILTON of the Undershore, Northfleet, Kent, Chemical
Engineer, do hereby declare the nature of this invention to be as follows:-
This inventigu relates to an improved form of drying apparatus, consisting of an
enclosed or air-tight chamber, within which there are a number of superposed
shelves so arranged that the material to be dried is fed on to the top shelf and is
moved by endless chains, carrying suitable scrapers from shelf to shelf till it
leaves the apparatus by the discharge outlet at the lower part of the chamber.
The apparatus is heated by steam pipes under each shelf or in any other manner.
The scrapers which keep the material in motion during its passage from shelf to
shelf through the apparatus are of two kinds,- -one being a solid scraper or push-
plate, and the other a scraper serrated on the top and bottom edges, such plain and
serrated scrapers being arranged so that there are two serrated scrapers between
two solid push-plates; that is to say,-one solid scraper is followed by two serrated
Scrapers, in which the serrations are so arranged that the furrows caused by the
first are broken up by the second; behind which again comes another solid scraper
or push-plate, and so on continuously.
These scrapers are attached to endless chains carried on spocket wheels, the
shafts of which are so arranged that one chain, (or pair of chains, if two are
employed) and its scrapers, serves for two adjoining shelves. Any number of
shelves and scrapers may be employed.
The scrapers and endless chains have an intermittent forward and backward
motion so as to rake the material and separate the wetter or imperfectly dried
material from the drier material enclosing it, and so bring it into contact with the
heated plates or shelves, or expose it to the hot atmosphere of the apparatus. The
movement of the chains and scrapers is not equal in both directions; a greater
forward movement being given, as for example,-The scrapers may move six
inches forward and three inches backward. By this means it will be seen that the
material is being constantly turned over and moved forward.
In the application of the apparatus to the drying of poisonous substances; as for
example, white lead, I employ a specially devised automatic feed arrangement by
which the material is fed slowly and in uniformly regulated quantities, into the
closed apparatus so as to ensure freedom from choking, and the material when dry,
is discharged from the bottom of the apparatus by a similar arrangement. The
fed and discharge is effected in the following manner :-Within a circular chamber
having flat, or other suitable sides, and inlet and outlet orifices immediately opposite
each other, there is a cylindrical shaft or block (hollow or otherwise) provided with
a number of large grooves or concave spaces (4 by preference) so that when one
groove is opposite the inlet hole or passage in the upper part of the chamber,
another groove is immediately opposite the discharge opening or outlet in the
lower part of the chamber, while the other two grooves are closed and covered by
the circular and side walls of the chamber.
This enclosed grooved feed block or shaft, works steam or gas-tight within the
chamber, so that there is no communication between one grooved or concave space
and the others.
Immediately beneath the delivery or outlet passage of the circular chamber, a
revolving scraper or wiper is provided to remove or wipe the material from the
grooves or concavities as, by the intermittent revolution of the grooved block,

page_text: they are brought successively opposite the discharge passage of the chamber above
referred to. This scraper or wiper is fixed on a shaft working in bearings in a
chamber immediately beneath and attached to the circular chamber, and revolves
continuously, being driven in any suitable manner. Upon the spindle of the
revolving scraper, is fixed a small crank or arm, connected by a link, with another
crank and lever upon the spindle of the revolving cylindrical grooved block, and to
a pawl which engages with a ratchet wheel also fixed on the spindle of the
cylindrical grooved feed block, by which means said block is intermittently rotated,
so that when the scraper is cleaning or wiping out one groove or concavity, the
revolving block is at rest and is receiving a charge of the material in the opposite
groove or cavity above; but whilst the scraper is continuing the other half of its
complete revolution, the grooved feed-block is, by means of the ratchet wheel and
pawl, rotated another quarter of a complete revolution so as to bring the succeeding
groove or cavity opposite the outlet opening in the chamber, for being acted upon
by the scraper, and for receiving another charge of material in the opposite groove
or cavity above.
The material or substance to be fed into the apparatus is conveyed by means of
a conveyor trough and worm or other suitable means, to the upper or inlet hole of
the circular chamber.
In order to remove the vapour given off' in the process of drying, air previously
heated or otherwise, may be forced or drawn over the material in any well known
manner, the apparatus being always kept closed by the automatic feed and
discharge apparatus before referred to.
In the case of drying white lead, I prefer to draw the air over the material, so
that the dust laden air passes over wet material entering the apparatus, and which
removes the dust from the air before leaving the apparatus. Also by aspirating
the air and maintaining a slight vacuum in the apparatus, any leakage of dust
from the apparatus into the room is avoided.'"
The air after leaving this apparatus may, if necessary, be passed through
any dust collecting arrangement or device before being discharged into the
atmosphere.
Dated this 27th day of January 1894.
OSWALD HAMILTON.
COMPLETE SPECIFICATION.
A New or Improved Apparatus for Drying White Lead or other
Material.
1, OSWALD HAMILTON, of the Undershore, Northfleet, Kent, Chemical
Engineer, 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 :-
This invention relates to an improved form of drying apparatus, illustrated by
the accompanying sheet of drawings, in which
Fig. 1 is a longitudinal elevation, with nearly all the side plate removed;
Fig. 2, is a sectional end elevation at A. B of Fig. 1 and Fig. 3 is a plan
view.
Within an enclosed or air-tight chamber a, there are a number of superposed
shelves b, so arranged that the material to be dried is fed on to the top shelf
through the inlet c, and is moved by endless chains d, carrying suitable scrapers e,
from shelf to shelf till it leaves the apparatus by the discharge outlet, f, at the
lower part of the chamber a.
The apparatus is heated by steam pipes g, under each shelf b, or in any other
suitable manner.
The scrapers e, which keep the material in motion during its passage from shelf

page_text: to shelf through the apparatus, are of two kinds,-one being a solid scraper or
push plate, and the other a scraper serrated on the top and bottom edges,
such plain & serrated scrapers being arranged so that there are two serrated
scrapers between two solid push-plates; that is to say,-one solid scraper is
followed by two serrated scrapers, in which the serrations are so arranged
that the furrows caused by the first are broken up by the second; bebind which
again comes another solid scraper or push-plate, and so ou continuously. These
scrapers e, are attached to endless chains d, carried on spocket wheels h, the
shafts of which are so arranged that one chain d (or pair of chains if two are
employed) and its scrapers e, serve for two adjoining shelves b. Any number of
shelves and scrapers e may be employed.
The scrapers e and endless chains d, have an intermittent forward & backward
motion, so as to rake the material and separate the wetter or imperfectly dried
material from the drier material enclosing it, and so bring it into contact with
the heated plates or shelves b, or expose it to the hot atmosphere of the
apparatus. The movement of the chains d & scrapers e, is not equal in both
directions, a greater forward movement being given, as for example, -The scrapers
may move six inches forward and three inches backward. By this means it will
be seen that the material is being constantly turned over and moved forward in its
passage through the apparatus.
The means (not shown in the drawing) for effecting this intermittent forward
and backward motion to the chains and scrapers may be of any convenient kind
applied to the vertical worm-shaft driving the worm-wheels on the spocket-
wheel shafts i, or otherwise.
Suitable means m, for taking up the slack or adjusting the tension of the endless
chains are provided externally on the apparatus as shown.
In the application of the apparatus to the drying of poisonous substances, as for
example, white lead, I employ a specially devised antomatic feed arrangement
described and shown in my Specification No. 1057 of 17th January 1894, by which
the material is fed slowly and in uniformly regulated quantities into the closed
apparatus through the inlet c, so as to ensure freedom from choking, and the
material when dry, is discharged from the bottom outlet f of the apparatus by a
similar arrangement. The feed and discharge is effected in the following manner :-
Within a cylindrical chamber having flat or other suitable sides, and inlet and
outlet orifices immediately opposite each other, there is a cylindrical shaft or
block (hollow or otherwise) provided with a number of large grooves or concave
spaces (4 by preference) so that when one groove is opposite the inlet hole or
passage in the upper part of the chamber, another groove is immediately opposite the
discharge opening or outlet in the lower part of the chamber, while the other two
grooves are closed and covered by the circular and side walls of the chamber.
This enclosed grooved feed block or shaft, works steam-tight within the
chamber, so that there is no communication between one grooved or concave space
and the others.
Immediately beneath the delivery or outlet passage of the cylindrical chamber, a
revolving scraper or wiper is provided to remove or wipe the material from the
grooves or concavities, as, by the intermittent revolution of the grooved block, they
are brought successively opposite the discharge passage of the chamber above referred
to. This scraper or wiper is fixed on a shaft working in bearings in a chamber
immediately beneath and attached to the cylindrical chamber, and revolves con-
tinuously, being driven in any suitable manner. Upon the spindle of the revolving
scraper is fixed a small crank or arm, connected by a link, with another crank or lever
upon the spindle of the revolving cylindrical grooved block, and to a pawl which
engages with a ratchet wheel fixed on the spindle of the cylindrical feed block, by
which means said block is intermittently rotated, so that when the scraper is cleaning
or wiping out one groove or concavity, the revolving block is at rest and is receiving
a charge of the material in the opposite groove or cavity above, but whilst the
scraper is continuing on its complete revolution, the grooved feed-block is, by

page_text: means of the ratchet-wheel and pawl, rotated another quarter of a revolution so as
to bring the succeeding groove or cavity opposite the outlet opening in the
chamber, for being acted upon by the scraper and for receiving another charge of
material in the opposite groove or cavity above.
The material or substance to be fed into the apparatus is conveyed by means of
a conveyor trough and worm, or other suitable means to the upper or inlet hole of
the cylindrical chamber.
In order to remove the vapour given off in the process of drying, air previously
heated or otherwise may be forced or drawn over the material in any well known
manner, the apparatus being always kept closed by the automatic feed and
discharge apparatus before referred to.
In the case of drying white lead, I prefer to draw the air over the material so
that the dust laden air passes over wet material entering the apparatus, and which
removes the dust from the air before leaving the apparatus. Also by aspirating
the air and maintaining a slight vacuum in the apparatus, any leakage of dust from
the apparatus into the room is avoided.
The air after leaving this apparatus may if necessary, be passed through
any dust collecting arrangement or device before being discharged into the
atmosphere.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what. I
claim is :-
1st. The improved drying apparatus constructed and operating as and for the
purpose herein described and shown by the drawing.
2nd. In apparatus for drying white lead and other material, the employment of
the automatic device for feeding the wet pasty-material into such apparatus in
regular & uniform quantities and for discharging the dried and finished material in
like manner, substantially as herein described.
Dated this 20th day of October 1894.
OSWALD HAMILTON.