Improvements in Perforated Grinding Mills for Reducing to a Fine Powder Hard Grindable Substances.
Year: 1889

page_text: Date of Application, 29th June, 1889
Complete Specification Left, 28th Mar., 1890-Accepted, 17th May, 1890
PROVISIONAL SPECIFICATION,
Improvements in Perforated Grinding Mills for Reducing to a Fine
Powder Hard Grindable Substances.
THOMAS WHITTAKER 141 Burnley Road, Accrington Lancaster, Engineer, do
hereby declare the nature of this invention to be as follows:-
The object of my invention is the introduction into perforated grinding mills used
to produce finely ground materials (having the usual frame work, crushing rollers,
and revolving pan with perforated bottom or segments guide scrapers for guiding
material on & off grinding track, and under-receiver); of an improved apparatus for,
collecting, and delivering the ground material, after it has passed through the
perforations, and thereby lessening the power required to drive grinding mill.
In carrying my invention into effect, I employ an annular plate or dish revolving
underneath the pan and at a slower rate than it. The ground material after passing
through the perforations of pan falls on to the revolving annular plate or dish, and is
carried round by same to one or more stationary scrapers, revolving or fixed..
The revolving annular plate or dish, may be supported from the central upright
shaft which carries pan, but revolving independently of same, and at fewer revolutions,
or by means of conical anti-friction rollers placed underneath. I do not confine
myself as to the mode of actuating said annular plate or dish, and said revolving
scraper. This may be done by belt or rope gearing from driving shaft of mill, or by
means of bevel and spur gearing from same, or it may be actuated from central shaft
or by any other means.
Heretofore the means of collecting ground material in a perforated grinding mill
has been as follows; Either the pan has had a stationary receiver under it which is
sometimes also the bed plate, and the material is scraped to the discharge pit by
scrapors fixed to underside of pan. Or there has been a receiver fixed to pan under-
neath it, and revolving with it at same rate; the material being discharged by fixed
or revolving scraper.
By my invention, the material is effectively collected at one place, and by running
the annular plate or dish, at a lower speed than pan, the friction due to the scrapers is
greatly diminished, and the mill takes considerably less power to drive...
Dated this 27th day of June 1889.
LAWRENCE WHITTAKER.
COMPLETE SPECIFICATION.
Improvements in Perforated Grinding Mills for Reducing to a Fine
Powder Hard Grindable Substances.
I, THOMAS WHITTAKER of 141 Burnley Road, Accrington in the county of
Lancaster 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 :---
My invention relates to improvements in perforated grinding mills for grinding
materials into a finely divided condition and having the usual frame work crushing
rolls, revolving pan with perforated bottom or segments, guide scrapers directing
material on and off the grinding tracks &c.
for
Heretofore the means of collecting ground material from a perforated grinding mill
have been as follows:-Either the revolving pan has had a stationary receiver under
t which is sometimes the bed plate onto which the ground material has fallen through
he perforations, and from which the said material is moved to the discharge way
or

page_text: pit by means of scrapers fixed on the underside of the pan or there has been a
receiver fixed to the pan underneath and revolving with it, whilst the material falling
thereon has been removed by fixed or revolving scrapers.
In both the above arrangements there is excessive motion between the scrapers
and the receiver and an unnecessary amount of power is used for the work to
be done.
Now the object of my invention is to provide improved apparatus whereby the
collecting and delivering of the ground material after it has passed through the
perforated bottom is efficiently effected with less expenditure of power.
In carrying my invention into practice I employ an annular plate or dish revolving
underneath the pan at a lower rate of speed than the said pan, in combination with a
scraper or scrapers. The said scraper or scrapers is or are fixed or stationary as
regards the discharge way or ways but may revolve on its or their axes.
The revolving annular plate or dish may be supported by the central upright shaft
which carries the pan whilst revolving independently thereof and at a slower rate of
speed, or the said plate or dish may be supported on conical anti-friction rollers, ball
bearings or any such contrivance placed underneath. I do not confine myself to the
mode of actuating the said revolving annular plate or dish and revolving scraper
which may be done by belt or rope gearing or by bevel or spur gearing actuated from
the mill driving shaft, the upright central shaft or other conveniently moving part.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a vertical section of a grinding mill constructed in accordance with my
invention, a is the revolving pan and bis the base plate, between these and directly
underneath the perforated bottom d is placed the annular plate or dish c. The said
plate or dish is constructed so that the upper surface slopes down from the inside to
the outside to facilitate the delivery of ground material. The annular plate is shewn
supported on three conical rollers, one of which made into the driving medium
actuates the dish by frictional contact and is driven by pulleys and a belt from the
driving shaft e, f is a revolving scraper actuated from the driving shaft e by a rope
and grooved pulleys.
Fig. 2 is a plan of the base plate of mill shewing the position in which the
supporting rollers are placed. a is the driving roller which is carried in a frame fixed
on the base plate the other two rollers 6 & care supported from the feet of the side
frames of the mill by bolts passing through them. The said rollers are so tapered
that the apex of the cones of which they are parts would all meet in the centre of the
annular plate.
Fig. 3 is a plan of a portion of the annular plate shewing a revolving scraper a
and the manner of supporting the same. The said scraper is conical and has upon
its surface one or more helical threads b b of a very coarse pitch standing up above
the surface about 2 inches and about one inch in width. The threads may be cast
in one piece with the conical body, or they may be secured thereto : the body may be
of wood and the thread composed of steel bristles in the manner of a brush. The
said scraper is mounted on a shaft e which is carried at one end by a swivel block d
and at the other in a bearing e fitted over a block g. As the scrapers becomes worn
by use it can be brought down a little by taking out the block g shewn in Fig. 5 and
thinning it.
Fig. 4 is a plan of a portion of the annular plate or dish shewing another mode
of driving. The said plate or dish has a groove round it. A driving rope passes
round the groove underneath two guide pulleys a, a and over a pulley 6 on the top
shaft of the mill by which rope is driven. Fig. 6 is a section of the plate or dish
shewing the groove.
It will be obvious that the precise details hereinbefore described and illustrated by
the accompanying drawings may be varied without departing from the nature of my
Invention.

page_text: 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 :-
First. Constructing grinding mills with an annular plate or dish supported under
the perforated pan but revolving at a lower rate of speed in combination with a
scraper or scrapers for the purpose set forth.
Second. Constructing grinding mills with an annular plate or dish supported
under the perforated pan but revolving at a lower rate of speed in combination
with a revolving scraper for the purpose set forth.
Did thin Texanty seventh day of March 1890.
Per pro J. T. KING,
W. B. Johnson,
Agent.