Improvements in or Applicable to the Construction of Mills for Grinding Flint, Stone, Bone, Glaze, and other like Substances.
Year: 1887

page_text: Date of Application, 17th May, 1887.
Complete Left, 22nd July, 1887.
Complete Accepted, 2nd Sept., 1887.
Improvements in or Applicable to the Construction of Mills for
Grinding Flint, Stone, Bone, Glaze, and other like Substances.
I, WILLIAM BOULTON, of Providence Foundry, Burslem, Staffordshire, Engineer,
do hereby declare the nature of the said Invention to be as follows:-
This invention relates to certain improvements in or applicable to the construction
of mills of the nature hereinafter described for grinding flint, stone, bone, glaze, and
other like substances, special objects of the improvements being to cause the material
being treated to be more evenly and regularly spread between the stones and the bottom
of the pan and consequently to be ground or pulverized in less time and with less
expenditure of power.
The grinding mills to which the present improvements are specially applicable are
constructed with a large pan generally made of wood, or iron, of any required
diameter, and the bottom of which is paved with hard stones. Centrally within this
pan there is placed an upright shaft which is revolved by suitable gearing, and is
provided with laterally extending and depending arms by means of which large
grinding stones or runners (usually weighing from about 20 to 30 cwt. each) are propelled
over the paved bottom of the pan. The material to be ground is introduced into the
pan with a proper proportion of water and as the heavy stones are revolved or pro-
pelled over the paved bottom of the pan the material is pulverized between them.
Circumscribing the said heavy stones is a wrought iron ring known as a slug iron
which is attached to arms within the pan, a space of about 3 to 4 inches being left
between the ring and outer casing in which space the centrifugal force caused by the
rotating operation of the machine causes the material being treated in its liquid state
to flow, and in which space it continues to float around with no tendency and without
the provision of means tending to positively cause it to again get under the revolving
stones.
As hereinbefore referred to, it is the special object of the present improvement to
remedy this defect by providing means for causing the material being ground to be
repeatedly brought to or towards the centre of the machine and under the stones after
it has been caused as aforesaid to travel towards the outer casing of the pan.

page_text: To accomplish this object, I insert one or more conduits or pipes made of cast iron
or other suitable material within or under the pavement of the pan for the purpose of
causing the material to be taken back to the centre of the pan by gravitation due to
the said centrifugal force causing the material to be raised at the periphery of the pan
several inches up the side of the casing, which gives a sufficient head to cause the
material to gravitate back to the centre. Or I can introduce a stop or baffler between
the slug iron and casing near to the entrance to the said pipe which runs under the
stones; or I allow it to run from the outer casing to a cistern, from which I pump it
up through the bottom of the pan to the centre; or I can use a circular trough
arranged above the revolving arms and around and adjacent to the centre shaft, and
pump the material into the said trough from which it runs down pipes leading to the
centre of the pan. Or I can effect the said object by pneumatic agency or by steam
pressure. The material under treatment may thus be positively carried back from the
periphery of the pan to its centre to be re-ground, by pumping or otherwise elevating
it or by the use of an archimedian screw working within the said conduit or pipe or
by other suitable means, and such process can be continuously carried on until the
material is sufficiently ground.
By such means I can with advantage run the pans at a greater speed, and instead
of using such heavy stones as are at present used can have them much lighter, and
can use sufficient to cover the whole width of the bottom of the pan, and can use more
arms than are at present used to propel the stones, and where it is more convenient
to use heavy stones I can suspend them by the use of springs in accordance with an
Invention forming the subject of Letters Patent which have been formerly granted to
me; and with such facilities I can grind the material in considerably less time than
is done by the method in prosent use and with a less expenditure of power.
In some cases I also propose to build the paving stones up the side of the casing so
as to form an additional grinding surface, if necessary correspondingly arranging the
driving arms, and removing the slug irons.
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C.,
Agents for the Applicant.

page_text: Grinding Flint, Stone, Bone, Glaze, and other like Substances.
I, WILLIAM BOULTON, of Providence Foundry, Burslem, in the County of
Staffordshire, Engineer, do hereby declare the nature of the said 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 certain improvements in or applicable to the construction
of mills of the nature hereinafter described for grinding flint, stone, bone, glaze and
other like substances; special objects of the improvements being to cause the material
being treated to be more evenly and regularly spread between the stones and the
bottom of the pan and consequently to be ground or pulverized in less time and with
less expenditure of power.
The grinding mills to which the present improvements are especially applicable
are illustrated in the accompanying drawings in which they are represented as
constructed with a large pan, 1, generally made of wood, or iron, of any required
diameter, and the bottom of which is paved with hard stones, 2. Centrally within
this pan there is placed an upright shaft, 3, which is supported in a footstep, 4, is
revolved by suitable gearing, 5, and is provided with laterally extending and depending
armis, 6, 7, by means of which large grinding stones or runners, 8, (usually weighing
from about 20 to 30 cwt. each) are propelled over the paved bottom of the pan, the
stones resting with all their weight thereon, or being suspended as described in the
Specification of Letters Patent No. 6461 granted to me on the 17th day of
April, 1884.
The material to be ground is introduced into the pan with a proper proportion
of water, and as the heavy stones are revolved or propelled over the paved bottom of
the
pan the material is pulverised between them.
Circumscribing the said heavy stones is a wrought iron ring, 9, known as a slug
iron which is attached to the arms within the pan, a space, 10, of about three to four
inches in width being left between the ring, 9, and outer casing, 1, in which space
the centrifugal force caused by the rotating operation of the machine causes the
liquid or semi-liquid material being treated to flow, and in which space it continues to
float around with no tendency, and without the provision of means tending to
positively cause it, to again get under the revolving stones.
As hereinbefore referred to, it is the special object of the present improvements to
remedy this defect by providing means for causing the material being ground to be

page_text: repeatedly brought to or towards the centre of the machine and under the stones
after it has been caused as aforesaid to travel towards the outer casing of the pan.
To accomplish this object, I insert one or more conduits or pipes, 11, made of cast
iron or other suitable material, within or under the pavement of the pan for the
purpose of causing the material to be taken back to the centre of the pan by
gravitation due to the said centrifugal force causing the material to be raised at the
periphery of the pan several inches up the side of the casing which gives a sufficient
head to cause the material to gravitate back to the centre. Or I can introduce stops
or baffler plates, 12, between the slug iron and casing near to the entrances to the
said conduits, 11, to cause the material to be raised higher in order to give it a
sufficient head (if not otherwise sufficient) to force itself back by gravitation to the
centre of the pan, or I can allow the material under treatment to run from the outer
casing to a cistern from which I can pump it up through the bottom of the pan to the
centre or I can use a circular trough, 13, arranged above the revolving arms and
around and adjacent to the centre shaft, and pump the material into the said trough,
from which it may run to the centre of the pan by pipes leading thereto. Or the
material under treatment may be positively carried back from the periphery of the
pan to its centre to be re-ground by the use of an archimedian screw, 14, (vide
Figs., 1, &, 2, of the accompanying drawings, respectively a sectional elevation and
a plan view) working within the said conduit or pipe and actuated from the driving
shaft, 15, by a strap, 16, passing round pullies, 17, 18, or by other suitable means
such as by steam pressure or by pneumatic agency an example of which latter application
is given on the accompanying drawings in Figs. to, 5, respectively a sectional
elevation, plan view and enlarged detail view of the air-tap. In such latter appli-
cation, the pulley, 17, is replaced by a worm, 19, which engages with a suitably
supported worm wheel, 20, having a stud, 21, which at each revolution actuates a
rod, 22, guided at, 23, and weighted at, 24, and which at the upper end is connected
to a lever, 25, actuating the plug, 26, of the tap, 27, which controls the supply of air
admitted by the pipe, 28, from an air pump or accumulator to a closed box, 29, which
is in communication with the said conduit or conduits, 11, and to which the material
escapes from the side of the pan by an outlet, 30, adapted with a valve, 31, normally
tending to keep such outlet closed, a small supply of water sufficient to keep the
material liquid, being, if required, also admitted to the box, 29, by means of a
pipe, 32, adapted with a tap, 33. The plug, 26, and tap, 27, are formed with air
passages, 34, 35, the main air passage, 34, being for admitting the air to the box and
forcing the material therein along the conduit or conduits, 11, to the centre of the
pan, and the smaller air passages, 35, being for allowing of the escape of the air
from the box when the plug, 26, is turned off so as to allow more of the material to
enter the box, 29. 36, represents a doorway through which the chamber, 29, and
conduit, 11, may be cleaned out.
By such means I can with advantage run the pans at a greater speed, and instead
of using such heavy stones as are at present used can have them much lighter and
can use sufficient to cover the whole width of the bottom of the pan, but where it is
more convenient to use heavy stones I prefer to suspend them by the use of springs as
represented at, 37, in accordance with the Invention forming the subject of the
herein before referred to Letters Patent granted to me, and can use more arms than
are at present used to propel the stones, and with such facilities I can grind the
material in considerably less time than is done by the method in present use and with
a less expenditure of power, and such process can be continuously carried on until
the material is sufficiently ground.
In some cases I also find it of advantage to build the paving stones up or partly up
the inner side of the casing so as to form an additional grinding surface, if necessary
correspondingly arranging the driving arms and removing the slug iron.
According to another modification, I effect the repeated grinding of the material
under treatment in a series of pans so arranged relatively to each other as that such
material gravitates from the periphery of the one pan to near the centre of the one
next adjacent, and so on.

page_text: Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is :-
1. The herein before described improvements in or applicable to the construction of
grinding mills of the nature herein before described.
2. In such mills, the provision of means for causing the material being ground to
be repeatedly brought to or towards the centre of the machine so that it may be
repeatedly passed under the grinding stones without cessation of the operation of the
machine substantially as hereinbefore described.
3. The hereinbefore described improved means of attaining such object, the same
consisting essentially in the provision of conduits or passages leading from the
periphery of the pan at the part beyond the outer edges of the rotating stones where
the material normally accumulates, to or adjacent to the centre of the pan within the
inner edges of such stones, and through which conduits or passages the material
under treatment is caused to pass by any suitable means substantially as hereinbefore
described.
4. The improved arrangements of apparatus for attaining such object, substantially
as hereinbefore described with reference to the accompanying drawings.
5. The hereinbefore described improved arrangement of series of pans for effecting
the repeated grinding of the material under treatment.
Dated this 14th day of Tulu 1987
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C.,
Agents for the Applicant..