Improvements in Apparatus for Drying Granular, Pulverulent, or similar Materials.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Drying Granular, Pulverulent, or
similar Materials.
I, WILLIAM CRAWFORD, of 376 George Street, Aberdeen, North Britain,
Engineer, do hereby declare the nature of this invention to be as follows:-
The objects of my invention are to effect the perfect drying of such materials or
substances by a succession of exposures during which every portion is equally dried
so as to issue from the process in a homogeneous condition and also to enable
large quantities of materials or substances to be effectively treated in a given
time.
I propose generally to use heat generated in a furnace from any kind of fuel, but
gas or the vapour of inflammable oils may be adopted, and to apply such heat
direct to the interior of the apparatus, but my invention may be carried out by
radiated heat of flame, gases or steam enclosed in a casing or jacket around the
apparatus.
The apparatus will preferably consist of a vertical cylindrical chamber into
which the heat enters at the bottom and escapes by a chimney at top and the
materials or substances to be treated are fed in by a hopper at top falling into a
horizontal tray, forming the first of a series, mounted upon a revolving shaft driven
by suitable gearing at any required rate of speed. Upon this first tray the charge
is distributed into a perfectly level layer by means of a fixed arm so shaped as to
spread the material evenly over the tray from the centre to the periphery.
As this first tray completes nearly one revolution a "scraper" arm sweeps the
material into a hopper from which it falls down a spout onto the next tray where
it is similarly treated and so on from tray to tray, being constantly exposed to
the heat, but a fresh surface being so exposed on each successive tray by the
layer of material being broken up in passing down from each tray to the next
and on reaching the bottom it is dischaged either by hand or by automatic
mechanism.
Provision will be made for the vertical expansion of the apparatus, when
working under its heated condition, so that the "scraper " arms may operate close
down upon the upper surfaces of the revolving trays and also, in treating certain
materials, for giving a shaking motion to the hoppers and spouts through which the
materials pass, from tray to tray, so as to ensure that they do not adhere to and
clog in their passage.

page_text: Improvements in Apparatus for Drying Granular, Pulverulent, or
similar Materials.
I, WILLIAM CRAWFORD late of 376, George Street, Aberdeen, North Britain
now of 60, Holly Avenue in the City of and County of Newcastle-upon-Tyne
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 :-
The objects of my invention are to effect the perfect drying of such materials or
substances by a succession of exposures during which every portion is equally dried
so as to issue from the process in a homogeneous condition and also to enable
large quantities of materials or substances to be effectively treated in a given
time.
I propose generally to use heat generated in a furnace from any kind of fuel, but
gas or the vapour of inflammable oils may be adopted, and to apply such heat
direct to the interior of the apparatus, but my invention may be carried out by
radiated heat of flame, gases or steam enclosed in a casing or jacket around the
apparatus.
The apparatus will preferably consist of a vertical cylindrical chamber into
which the heat enters at the bottom and escapes by a chimney at top and the
materials or substances to be treated are fed in by a hopper at top, falling into a
horizontal tray, forming the first of a series, mounted upon a revolving shaft driven
by suitable gearing at any required rate of speed. Upon the first tray the charge
is distributed into a perfectly level layer by means of a fixed arm so shaped as to
spread the material evenly over the tray from the centre to the periphery. As this
first tray completes nearly one revolution a scraper arm sweeps the material into a
hopper from which it falls down a spout on to the next tray, where it is similarly
treated and so, on from tray to tray, being constantly exposed to the heat but a
fresh surface being so exposed on each succession tray, by the layer of material
being broken up in passing down from each tray to the next and on reaching the
bottom it is discharged either by hand or by automatic mechanism.
Provision will be made for the vertical expansion of the apparatus when working
under its heated condition so that the scraper arms may operate close down upon
the upper surface of the revolving trays and also, in treating certain materials, for
giving a shaking motion to the hoppers and spouts through which the materials
pass, from tray to tray so as to ensure that they do not adhere to and clog in their
passage.
DESCRIPTION OF DRAWINGS.
The accompanying two sheets of drawings shew to a scale of inch per foot
a sectional elevation Fig. 1. and a sectional plan above one of the series of
revolving trays Fig. 2.
The apparatus is here shewn as specially for drying ground superphosphates
enclosed in brickwork and is beated by coke or other fuel by fires placed at A. A.
in the brickwork opeuing into the interior by the flues B. B. and the gases after
circulating through the apparatus escape into the chimney by the flue C or, instead
of escaping direct to the chimney, the waste heat may be utilised in a flue or flues
around the brick casing to prevent radiation and loss of heat from the chambers.

page_text: The chamber being closed at top by metal plates D, or fire clay slabs, supported-
upon cross girders E.
The main vertical shaft F is mounted in a footstep G and in a carriage H at top
and is driven from the engine by a bevel pinion J working into a bevel wheel K
keyed on the shaft. In this case there are four trays L, L, L' and L keyed on
the shaft, each having a truly level top surface and each fitted with an adjustable
distributing arm M1, M2, M, or M carried by a suspended frame N, which does.
not revolve, by which the material as it is delivered to the upper tray L' from the
"hopper" O is levelled over the surface of the tray to any desired thickness
by the revolution of the tray thus exposing a layer of equal thickness to the
heat.
As the tray nearly completes one revolution a scraper arm P¹ carried in the
suspended frame N sweeps the partially dried material into the hopper O² whence
it falls onto the next tray L' breaking up, in falling and is then again levelled by
the distributing arm M2 exposing a fresh surface to the heat, and from this tray it
is swept by the scraper arm P2 into the hopper Os and delivered on to the third
tray L and so on until it reaches the last tray a fresh surface of material being.
each time exposed to the heat and when thus thoroughly and homogeneously dried
it is discharged through the lowest hopper and conveyed from the apparatus by
hand or automatic mechanism. As the main shaft F to which the trays are-
screwed will lengthen vertically when the apparatus is heated, carrying the trays
with it, the distributing arms must be adjusted to allow for such variation so as to
adjust the thickness of each layer of the material and as the scraper arms must
always be in scraping contact with the surface of the trays, provision is made for
such adjustment by the scraper arms being suspended from the frames N each of
which is hung upon a pin Qat its outer end, upon which pin it is free to rise as the
shaft F lengthens and alters the level of the trays and, as the distributing arms M
are also suspended from the frames the required thickness of the layer of material
once fixed is maintained.
In treating materials which are liable to cake a shaking motion may be given to.
the hopper spouts to break up the caked material and caused to be spread in an
equal layer on the trays.
The dimensions of the apparatus, the number of the trays and the rate at which
they revolve will vary according to the nature and condition of the materials to be
treated and the heat within the chamber may be regulated by suitable dampers in
the flues.
In drying by radiated heat the chamber may be of cast iron or iron plates.
surrounded by a jacket in which the products of combustion circulate which jacket
may be formed in the brickwork or may be of metal or iron plate enclosed so as to
protect it from external radiation.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. An apparatus for drying granular, pulverulent or similar materials in which a
series of slowly revolving horizontal trays disposed on a driven vertical shaft are
enclosed in a chamber exposed to heat which may be the products of combustion of
coal coke oil gas or other fuel or hot air, circulating in said chamber in direct
contact with the material or may circulate in a casing or jacket around it containing
such products of combustion, or steam from which casing or jacket, the heat is
radiated to the interior of the chamber, provision being made for distributing the
materials into a layer of uniform thickness on each successive tray and after
exposure thereon for sweeping it down a spout into the next tray in a disintegrated
condition to be again levelled to a uniform thickness and so on to the next and each
succeeding tray and finally discharged from the lowest tray homogeneously dried
substantially as described and in one form shewn.

page_text: 2nd. The apparatus comprising various parts combined, constructed and operating
substantially as described and shewn by the drawings herewith.
Dated this 11th day of March 1897.
T. J. DANSON,
Newcastle-upon-Tyne, Agent for Applicant.