IMPROVEMENTS IN APPARATUS FOR SEPARATING DUST FROM AIR, CHIEFLY DESIGNED FOR USE IN FLOUR MILLS
Year: 1884

page_text: I HENRY HARRIS LAKE, of the firm of Haseltine, Lake, and Co Patent Agents,
Southampton Buildings, in the County of Middlesex do hereby declare the nature
of my invention for "IMPROVEMENTS IN APPARATUS FOR SEPARATING DUST FROM
AIR, CHIEFLY DESIGNED FOR USE IN FLOUR MILLS" 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 apparatus for separating and collecting dust or the like
from air by means of air-suction, and is more particularly adapted for use in
purifying grits and middlings and in collecting the dust from the dust chambers
employed in flour mills,
The said invention comprises improvements in the apparatus described in the
specification of former Letters Patent dated March 19th A.D 1884, N° 5155 and it
consists in introducing air under a certain pressure into the space or chamber within
the rotating filtering-cloth which is not acted upon by the air-suction; it also
comprises a modification of the grate arranged below the said filtering-cloth, and
a modified form of one of the rollers over which the said cloth runs, all as hereinafter
described.
In the accompanying drawing.
Figure 1 is a side-view, partly in section, of an apparatus for purifying grits and
middlings, showing part of the improvements.
Figure 2 is an end-view of the same, partly in section.
Figure 3 is a view showing the filtering cloth when employed as a dust-collector,
and,
Figure 4 is a view of a portion of one of the improved guide-rollers over which
the filtering-cloth is made to run in some cases, preferably when employed for
collecting the dust from dust-chambers as shewn in Figure 3.
B indicates the moving endless filtering-cloth, e the suction-space within the
latter, and f the space which is not disturbed by the air suction.

page_text: M indicates an opening in the end-plate a¹ closing one end of the space f, and
M is an air-conduit connecting the said space f with a fan or blower C¹, through
the said opening M. A current of air is introduced into the space f for a purpose,
hereinafter described.
The dust or other light matter, adhering to, and carried along by, the moving
filtering-cloth, is beaten off by the beaters i arranged within the space e' through
which no air-current passes, and striking against that portion of the filtering-
cloth B passing before the said space f, as described in the said former specification.
I have found in practice that after a continued use of the filtering-cloth the particles
of dust or other light matter entering the meshes or interstices of the filtering-
cloth, are not beaten off by the beaters, and will gradually fill up the said interstices
and interfere with the passage of the air-current through the said cloth. In order
to remove this difficulty, I introduce a current of air into the space f, through the
conduit M¹ and opening M, and as the said space f is closed on all sides except at M,
the air blown into the said space is compelled to pass out through the meshes or
interstices of that portion of the cloth B passing before the space f. By introducing
air under a certain pressure into the space f the portion of the cloth opposite the
said space will stretch like an air-cushion thus slightly enlarging the meshes of tho
cloth, and at the same time the particles of dust which have entered the said meshes
will be blown out, thus cleaning the latter so that, at the end of each revolution,
the filtering-cloth will commence to pass before the suction chamber in a thoroughly
cleaned condition.
L
. .
As the portion of the cloth B passing before the space f is stretched by the air
as above stated, the dust or other matter adhering to the said cloth will come off
more readily than heretofore, when the beaters i strike against the said portion.
When the filtering-cloth is used in a machine for purifying grits and middlings,
and is arranged directly over the rocking-siove E, 'as shewn in Figures 1 and 2 of
the drawing and as fully described in the said former specification, may, in some
cases, substitute for the grate of grooved bars there described, a similar grate of
bars having a projecting ridge of acute-angular or convexed form, the said bars j
being arranged either longitudinally or transversely to the filtering-cloth B and
covering up about one-half of the open area between the said filtering-cloth and
the rocking-sieve. The ridged bars ; may either be connected with the rocking-
sieve and partake in the rocking movement of the latter, as described in the said
former specification, or they may be rigidly secured to the frame of the machine
and form a stationary grate between the rocking-sieve and the moving filtering-
cloth. The object of the modified form of grate is only to compress or intensify
the current of air passing through the said rocking sieve, so as to cause all the
light substances, once carried above the said grate, to adhere to, and be removed
by, the moving cloth B, (so that they will be prevented from falling back on the
rocking-sieve,) and not to separate from them the heavier particles as described in
the said former specification.
When employing the said filtering cloth B in a dust-chamber for the purpose of
collecting the dust (as shown in Figure 3 of the drawing in which the space not
disturbed by the suction air, is formed by the plates D D¹, g¹ and g¹ and the trough g
of the conveyor g², and as will be readily understood from the said specification),
a greater suction-area of the said cloth B and a better frictional contact of the
latter with the guide-rollers than heretofore may be obtained by substituting for
the two rollers b and 6, Figure 2, a single roller 65 and making the latter hollow
and open so as to allow the suction-air to act through the same upon the filtering
cloth B.
The roller b³, part of which is shown in detail in Figure 4, consists, for the said
purpose, of a suitable number of discs t upon which are screwed narrow boards u
placed edgewise, or thick plates u¹ laid flat upon the circumference of the said
discs, t, so that open spaces will remain between the said boards u or plates u¹.
As will be seen from Figure 3 of the drawing the air suction will draw in 'the
dust through the open spaces between the several plates or boards, and discs of the
! 4

page_text: roller 65, and also cause the filtering-cloth passing over the said roller to slightly
enter the said spaces so as to prevent it from slipping.
.
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
First. The combination with the space f, of a moving filtering-cloth not acted
upon by the air-suction, and an air-conduit feeding the said space with air under
pressure, substantially as, and for the purpose, specified.
Second. The grate consisting of the ridged bars; arranged and combined,
substantially as, and for the purpose, set forth.
Third. The roller 6 having open spaces formed by the discs t with bars secured
to their circumferences, substantially as, and for the purpose, set forth.
Dated this 11th law of Ontak.. 1001
HASELTINE, LAKE & Co.,
For the Applicant.