An Improvement in Middlings Purifiers.
Year: 1891

page_text: Date of Application, 21st Oct., 1891
Complete Specification Left, 19th July, 1892-Accepted, 27th Aug., 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by HENRY SIMON, at present of Vienna, in the
Empire of Austria, Civil Engineer.]
An Improvement in Middlings Purifiers.
I, JOHN IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and Chartered Patent Agent, do hereby
declare the nature of this invention to be as follows:-
In middlings purifiers, the material travels along a sieve subject to the action of
air currents rising through the sieve. As this sieve is usually made of silk or other
texture, the air currents which pass through adjoining meshes are necessarily close
together, being separated only by the threads constituting the fabric, and, as the
middlings become thinner and thinner as they travel along the sieve, much of the
air draught towards the tail of the sieve is ineffective.
Many attempts have been made to effect regulation and control of the
air currents after they have passed through the material on the sievo, as for
example in the purifiers of Simon and Seck known as the "Reform Purifiers" in
which a grating of channels is arranged immediately over the sieve, or in
Higginbottom's Purifiers in which perforated metal plates are placed over the sieve
with depositing chambers above them, or in Parkinson's Purifiers in which the
sifting surface is narrowed towards the tail, and depositing chambers are arranged
at the sides of the sieve and above it.
These arrangements, though more or less successful, are defective inasmuch as
they do not deal with the passages for air through the sieve itself.
Sometimes sheets of zinc or other metal, perforated with holes of various sizes
and numbers, have been employed, but they involve serious difficulties in jointing
them and tightly straining them so as to present the flat surface required throughout
the whole length of the sieve; moreover they require a heavy sieve frame which is
objectionable, especially as the sieve has to oscillate very rapidly.
Now, according to this invention, there is employed for the sieving surface or
part of it, parchment either natural or artificial, or paper, cardboard or like
material which is thin, light and strong, and has the quality of expanding when
moistened, so that the sheet being fixed on the frame of the sieve in a moist
condition, becomes tightly strained and flat when it is dry. Sheets of this material
are perforated with holes which vary in size and number on a given area in
different parts of the sieve, the size of each hole being increased and their number
being diminished towards the tail end so as to suit the increased size and diminished
number of the granules as they travel along the sieve. Thus, without encountering
the difficulties attending the use of metal sheets, the air draught is materially
economised and distributed much more uniformly over the middlings, so as to
separate more effectually the lighter portions, than with sieves as they are usually
constructed. It is to be understood that, along with a parchment sieve, as above
described, any of the known apparatus employed in the various purifiers above
referred to may be used for raising and collecting the fine particles lifted by the
air currents. These apparatus are rendered much more efficient by having to deal
with air currents which can be properly regulated before they pass through the
material undergoing purification; and the result is a more satisfactory purification
and a more complete collection of dust with the expenditure of a reduced quantity
of air.
Dated this 21st day of October 1891.
ABEL & IMKAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
An Improvement in Middlings Purifiers.
1, JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and Chartered Patent Agent, 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:-
In middlings purifiers, the material travels along a sieve subject to the action of
air currents rising through the sieve. As this sieve is usually made of silk or other
texture, the air currents which pass through adjoining meshes are necessarily close
together, being separated only by the threads constituting the fabric, and, as the
middlings become thinner and thinner as they travel along the sieve much of the
air draught towards the tail of the sieve is ineffective.
Many attempts have been made to effect regulation and control of the air
currents after they have passed through the material on the sieve, as for example
in the purifiers of Simon and Seck known as the "Reform Purifiers" in which a
grating of channels is arranged immediately over the sieve, or in Higginbottom's
Purifiers in which perforated metal plates are placed over the sieve with depositing
chambers above them, or in Parkinson's Purifiers in which the sifting surface is
narrowed towards the tail, and depositing chambers are arranged at the sides of the
sieve and above it.
These arrangements, though more or less successful, are defective inasmuch as
they do not deal with the passages for air through the sieve itself.
Sometimes sheets of zinc or other metal, perforated with holes of various sizes
and numbers, have been employed, but they involve serious difficulties in jointing
them and tightly straining them so as to present the flat surface required throughout
the whole length of the sieve; moreover they require a heavy sieve frame which
is objectionable, especially as the sieve has to oscillate very rapidly.
Now, according to this invention, there is employed for the sieving surface or part of
it, parchment either natural or artificial, or paper, cardboard or like material which is
thin, light and strong, and has the quality of expanding when moistened, so that
the sheet being fixed on the frame of the sieve in a moist condition, becomes tightly
strained and flat when it is dry. Sheets of this material are perforated with holes
which vary in size and number on a given area in different parts of the sieve, the
size of each hole being increased and their number being diminished towards the
tail end so as to suit the increased size and diminished number of the granules as
they travel along the sieve. Thus, without encountering the difficulties attending
the use of metal sheets, the air draught is materially economised and distributed
much more uniformly over the middlings, so as to separate more effectually the
lighter portions, than with sieves as they are usually constructed. It is to be
understood that, along with a parchment sieve, as above described, any of the
known apparatus employed in the various purifiers above referred to may be used
for raising and collecting the fine particles lifted by the air currents. These
apparatus are rendered much more efficient by having to deal with air currents
which can be properly regulated before they pass through the material undergoing
purification; and the result is a more satisfactory purification and a more complete
collection of dust with the expenditure of a reduced quantity of air.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A sieve for middlings purifiers consisting in whole or in part of, a sheet of
parchment or equivalent material stretched on a frame, substantially as and for the
purposes set forth.

page_text: 2. The combination of a sieve such as is above referred to with any of the
devices employed in middlings purifiers for raising and collecting the fine particles
separated by the air currents.
Dated thin 10th 1
1000
ABEL & IMRAY,
Agents for the Applicant.