IMPROVEMENTS IN MACHINERY OR APPARATUS FOR SIFTING, WASHING, AND OTHER KINDRED PURPOSES
Year: 1875

page_text: LETTERS PATENT to John Twist, of 8, Quality Court, Chancery Lane,
in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN MACHINERY OR APPARATUS FOR SIFTING, WASHING, AND OTHER KINDRED
PURPOSES."
Sealed the 29th October 1875, and dated the 26th June 1875.
PROVISIONAL SPECIFICATION left by the said John Twist at the
Office of the Commissioners of Patents, with his Petition, on the
26th June 1875.
I, JOHN TWIST, of 8, Quality Court, Chancery Lane, in the County of
Middlesex, do hereby declare the nature of the said Invention for "Iм-
PROVEMENTS IN MACHINERY OR APPARATUS FOR SIFTING, WASHING, AND OTHER
KINDRED PURPOSES," to be as follows:
My apparatus consists,--
First. Of a perforated cylinder (preferably sheet iron or zinc) or of
wirework stretched round a suitable framework. This cylinder has a
horizontal shaft passing through it diagonally instead of concentrically,
that is, supposing the cylinder to be two feet in diameter and to average

page_text: three feet in breadth, and the axis of the cylinder to be in the same
vertical plane as that of the horizontal shaft, the periphery of the
cylinder would be only an inch or two above the horizontal shaft and
twenty or so inches below it at one end, while at the other end it would
be twenty or so inches above the shaft and only an inch or two below.
The ends of the cylinder, instead of being at right angles with its axis,
are made perpendicular to the horizontal shaft, and one end has a disk
of wood, metal, or any other substance fixed to it concentric with the
shaft, and covering every portion of the cylinder end. A door in this
disk is made to open so as to allow materials for sifting to be passed into
or out of the cylinder. The other end of the cylinder is closed by a
plate of wood, or sheet iron, or other convenient material. The hori-
zontal shaft has bearings on each side, and the whole cylinder is usually
enclosed in a box having a hole cut out large enough to expose the
disk and no more. This casing is solely to keep the dust from flying
about.
2nd. To work the apparatus the horizontal shaft (propelled either by
hand or machine power) is rotated till the end of the cylinder covered
by the disk is at the highest point, and the axis of the cylinder and shaft
are in the same vertical plane. The door in the disk opening into the
cylinder is now opened, and the cylinder partially filled with cinders and
ashes (or any other substance requiring sifting). The door is then closed
and fastened, and the whole made to revolve until the ashes or dust
has been sufficiently eliminated through the perforated cylinder. The
rotation is now stopped at the point where the two axes are in the same
vertical plane, and where the end of the cylinder covered by the disk is
lowest. The door is now opened, and the cinders or lumps roll down the
inclined bottom of the cylinder and out through the door, leaving the
cylinder empty for a fresh charge.
3rd. The the cylinder can be made to rotato partially in water, in which
case it will be admirably adapted for washing roots, coprolites, lumps of
mineral, and other similar articles.
4th. I sometimes make the end of the cylinder not covered by the
disk perpendicular to the axis of the cylinder instead of to the shaft,
and then perforate the end also. In such case care must be taken to
counterbalance the cylinder, so that when empty it will stand in
equilibrio in any position, or else have a slight natural tendency to
cause the door in the disk to be uppermost, consequently, when all the

page_text: lumps have fallen out it will require the most trifling effort to place the
cylinder in the right position for filling, and it will naturally stand in that
position when empty, so that it can be filled without being held. I also
as a rule leave the portion of the the cylinder immediately behind the door
unperforated along the whole length, so as to prevent the cinders from
sticking on opening the door, and thus preventing the easy discharge.
SPECIFICATION in pursuance of the conditions of the Letters Patent,.
filed by the said John Twist in the Great Seal Patent Office on
the 24th December 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
TWIST, of 8, Quality Court, Chancery Lane, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of June, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Twist, Her special
licence that I, the said John Twist, my executors, administrators, and
assigns, or such others as I, the said John Twist, my executors, admi-
nistrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN MACHINERY
OR APPARATUS FOR SIFTING, WASHING, AND OTHER KINDRED PURPOSES," upon the
condition (amongst others) that I, the said John Twist, my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the dato
of the said Letters Patent.
NOW KNOW YE, that I, the said John Twist, do hereby declare
the nature of my said Invention, and in what manner the same is to

page_text: Drawings, and to the figures and letters of reference marked thereon:—
My apparatus consists,-
First. Of a perforated cylinder A (preferably of sheet iron or zinc) or
of wirework, silk, or any other material requisite for sifting purposes,
stretched round or worked on to a suitable framework. This cylinder
has a horizontal shaft D passing through it diagonally instead of con-
centrically, that is, supposing the cylinder to be two feet in diameter
and to average three feet in breadth, and the axis of the cylinder to be
in the same vertical plane as that of the horizontal shaft, the periphery
of the cylinder would be only an inch or two above the horizontal shaft
and twenty or so below it at one end, while at the other end it would
be twenty or so inches above the shaft and only an inch or two below.
In practice I usually dispense with the portion of the shaft passing
through the cylinder, and use two journals fastened to the cylinder, and
The ends of the
corresponding to the ends of the supposed shaft.
cylinder, instead of being at right angles with its axis, are made perpen-
dicular to the horizontal shaft, and one end has a disk C of wood, metal,
or any other substance fixed to it concentric with the shaft, and covering
every portion of the cylinder end and the space occupied by the said
cylinder end during its revolution. A door B in this disk is made to
open so as to allow materials for sifting to be passed into or out of the
cylinder. The outer end of the cylinder is closed by a plate of wood, or
slicet iron, or other convenient material. The horizontal shaft has
bearings on each side, and the whole cylinder is usually enclosed in a
box E, having a hole cut out large enough or nearly so to expose the
disk C. This casing is solely to keep the dust or other fine particles
from flying about, and to keep separate the sifted substances (when
being ejected from the apparatus) from the siftings.
2nd. To work the apparatus the horizontal shaft D (propelled by hand,
as shown in Drawings, or by machine power) is rotated till the end of
the cylinder A (covered by the disk C) is at the highest point, and the
axis of the cylinder A and shaft D are in the same vertical plane. The
door in the disk C opening into the cylinder is now opened, and the
cylinder partially filled with substances requiring sifting, seperating, or
washing. The door is then closed and fastened, and the whole made to

page_text: revolve until the smaller particles have been sufficiently eliminated
through the perforated cylinder. The rotation is now stopped at the
point where the two axes are in the same vertical plane, and where the
end of the cylinder covered by the disk is lowest. The door is now
opened and the remaining contents of the cylinder roll down the inclined
bottom and out through the door through spout F, leaving the cylinder
empty for a fresh charge.
3rd. The cylinder can be made to rotate partially in water, in which
case it will be admirably adapted for washing roots, et cetera.
4th. I sometimes make the end of the cylinder not covered by the
disk C perpendicular to the axis of the cylinder instead of to the shaft,
and then perforate the end also. In such case care must be taken to
counterbalance the cylinder, so that when empty it will stand in
equilibrio in any position, or else have a slight tendency to cause the
door in the disk to be uppermost; consequently, when all the contents
have fallen out it will require the most trifling effort to place the
cylinder in the right position for filling, and it will naturally stand in
that position when empty, so that it can be filled without being held. I
also as a rule leave the portion of the cylinder immediately behind
the door unperforated along the whole length, so as to prevent the
contents from sticking on opening the door, and thus preventing the
easy discharge.
Of course there are innumerable ways in which my machine could be
modified when once its principles are known; a cone could be used
instead of a cylinder for instance; but what I claim as my Invention
is,—
1st. A rotary sifter, separator, or washer with a door on one end that
is alternately at the highest and at the lowest part of the sifter, so that
the sifter can be charged nearly full and also can be entirely emptied by
gravity through the same door in the end.
2nd. The use of a rotating perforated cylinder in which the axis of
rotation does not coincide with the axis of the cylinder, for the purposes
described.
3rd. The arrangement of a rotating chamber A of any convenient
shape, whether cylindrical, conical, rectangular, or otherwise, in such
manner that its inner surface shall generally be at an oblique angle with
the axis of rotation, for the purposes described.

page_text: 4th. The combination in a sifting machine of the disks C with the
casing E and the sifting chamber A.
5th. The special arrangement of machinery, substantially as described
in the foregoing Specification.
In witness whereof, I, the said John Twist, have hereunto set my
hand and seal, this Twenty-second day of December, in the year
of our Lord 1875.
Witness,
W. P. THOMPSON,
Patent Agent,
6, Lord St.,
Liverpool.
JOHN TWIST. (L.S.)