AN IMPROVEMENT IN PROCESSES OF MANUFACTURING MIDDLINGS FLOUR
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by George Huddleston Dana at
the Office of the Commissioners of Patents, with his Petition, on
the 1st July 1873.-A communication from abroad by George
Thomas Smith, of Minneapolis, County of Hennepin, in the State of
Minnesota, United States of America.
do
1
I, GEORGE HUDDLESTON DANA, of 16, Mark Lane, London, E. C.,
hereby declare the nature of the said Invention for "AN IMPROVEMENT IN
PROCESSES OF MANUFACTURING MIDDLINGS FLOUR," to be as follows:
It consists in a novel mode, system, or order of purifying, grinding, and
bolting the middlings, and of returning automatically the "middlings-
returns" to be re-purified, re-ground, and re-bolted.
Under ordinary circumstances I grind the wheat upon stones dressed
in the ordinary manner. The meal thus produced is bolted through an
ordinary reel bolt, and the merchantable flour conveyed to a flour room
or packer, and corresponds to the first grade of flour commonly produced
in merchant mills. The middlings are transferred to a purifier having
an upward draft of air, where the detached particles of bran and other

page_text: similar impurities are removed, such size or number of machines being
used as shall effect a thorough separation. These middlings are next
carefully re-ground, but it is not intended that the first grinding should
reduce all the granules to the desired standard of size, as the difference
in their hardness or toughness renders this impracticable. From this
stone the middlings, meal, or sharps is taken to a bolt (preferably a reel)
which I call a middlings bolt, clothed with such cloth as the required
grade of flour shall indicate, say a No. 10. If this middlings bolt were
of sufficient capacity to insure that all the flour which had been ground
fine enough should pass through its meshes, it would permit so many
specks to pass through as to seriously discolor the flour, hence I use a
bolt of such size that it shall be constantly overloaded, compelling a
large portion of the material (usually about one-third of the amount
which is fed in) to pass over the tail of the bolt. These middlings
returns as I call them are not all fine enough for flour, but a com-
paratively small portion of fine flour will serve to carry the specks over
the tail of the reel. By means of a suitable conveyor I carry thesc
middlings returns to a purifier, and subject them to a draft of air as they
move over the surface of a shaker, the head of which is clothed with a
fine cloth, say a No. 10, which allows the finer portions to fall through,
but takes out all of the specks and fine bran. A conveyor takes the
flour thus purified and mixes it with that from the recl bolt, or when it
is desired to mix them more intimately, the flour taken from this returns
purifier may be incorporated with the middlings meal before the latter is
delivered to the reel. The tail end of the middlings returns purifier is
clothed with a coarser cloth, so as to let the larger granules of the
returns fall through. Of course this material is freed from loose bran
and specks, it is therefore conveyed to the middlings stone and re-ground
with the middlings which came from the middlings purifier first
referred to.
It will be readily. understood that none or at least very few of

page_text: as I usually send the coarser returns directly to the stone, as stated
above. Therefore I prefer to put a No. 7 cloth on the tail of this returns
shaker, and convey such material as runs over at this point, if there be
any to the middlings purifier, and compel it to go through a heavy draft
again. The tail end of the shaker of this middlings purifier should
have a No. 4 cloth, thus insuring that nothing shall go over this point
affel

page_text: In carrying out my Invention I prefer to use certain machines which
I have invented, and for which Letters Patent were granted me March
26th 1873, as I believe them to produce better results and to be more
economical in their operation than any others now in use; yet as my
Invention, method, or process is adapted to be used upon any machines
which use an upward draft of air through the shaker I do not wish to
be restricted to their use.