Improvements in Dust Collectors.
Year: 1889

page_text: Date of Application, 13th Aug., 1889-Accepted, 14th Sept., 1889
COMPLETE SPECIFICATION.
Improvements in Dust Collectors.
We ROBERT LUCASS DOWNTON and JAMES WILLIAM SHEPPARD DOWNTON both
of 503 Chamber of Commerce Building in the City of St. Louis and State of
Missouri, one of the United States of North America, Millers, 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, reference
being had to the accompanying drawings, forming part of this specification and in
which:
Figure I is a vertical section through my improved Dust Collector.
Figure II is an enlarged detail view, illustrating the manner of adjusting the
brushes.
Figure III is an enlarged section taken on line III, III, Figure 1.
Figure IV. is a similar view, taken on line IV, IV Figure 1.
Figure V is an enlarged detail sectional view of the connection between the dead
air chamber and delivery flue and adjacent parts.
Figure VI. is a transverse section, taken on line VI, VI, Figure 1.
Figure VII, is a detail side elevation of the lower end of the machine.
The invention relates to a device intended more particularly for use in connection
with flour and other mills for arresting and collecting their dust, and the invention
consists in features of novelty hereinafter fully described and pointed out in the
claims.
We find that a large amount of fine dust that escapes the first settling action
adheres to the wall of the vont flue, and though a portion of this fine dust and flour
is saved by the action of an encased brush or scraper, still there is a considerable
portion of it that flows out with the current of air and is wasted. Our object, there-
fore, is to provide means for saving this material.
Referring to the drawings, 1 represents an outer casing, the upper part 1 of which
is preferably of the same size from top to bottom, and the lower part of which is
preferably tapering or smaller at its lower end than at its upper end. The part 1 of
this casing is provided with a tangential opening 2, through which the dust-laden air
enters.
3 represents an inner casing, the upper part 4 of which is proferably of the same
size from end to end and the lower part of which is tapering or smaller at its lower
end than at its upper end, and this lower part has perforations 30, as shown in the
drawings. This inner cylinder is smaller than the outer cylinder, forming an inter-
vening chamber 5.
The inner casing, 3-4, we term a vent flue. Inside of the wall or part 4 of the
vent flue is a screen or siuve 6, which, being smaller than the part of the flue, forms
a dead-air chamber 7.
S represents a central shaft, having bearing on a cross-piece 9 at its upper end, and
a cross-piece 10 at its lower end. On the upper portion of this shaft are arms 11,
to the outer ends of which are secured brushes or wipers 12. Each brush is enclosed
by a housing or casing 13, as shown in Fig. III. The brushes bear or rub against
the inner surface of the screen 6, as the shaft 8 revolves. The brushes may be
adjusted to bring the desired pressure against the screen at all times by means of set
screws 14, working in the backs of the housings or casings 13, and jamming against
dove-tailed blocks 15 that carry the brushes, and that slide in the horizontal ends 16
of the housing. Upon the shaft S are arms 17, which extend into the dead-air
chamber 7, and on their ends are scrapers 18.
19 represents a tube or delivery flue connecting with the dead air chamber at 20.

page_text: 21 represents vertical rods or arms located in the dead-air chamber, and secured to
and carried by the arms 17 or scrapers 18.
100 represents a trough forming the bottom of the dead air chamber, upon the
inner edge of which the arms 17 bear. To form a joint here that will exclude
the air, we place a circular shield or ring 101 on the arms 17 that extends above the
bottom of the screen 6, and beneath the top inner edge of the trough, thus forming
a lap joint.
At the lower end of the machine a cone or cylinder 22 is located, and which is
held concentrically within the cylinder by menus of brackets or fastenings 23, by
which it is secured to the cylinder.
On the lower end of the shaft S may be secured a delivery screw or conveyer 24,
and beneath this are arranged one or more pairs of valves 25-we have shown two
pairs, each pair is pivoted at 26 to the lower end of the casing, and each valve is
provided with a counterweight 27, which counterweights hold the valves closed, as
shown in Fig. 1.
As the flour and dust collect in the upper pair of valves the material finally
owing to its weight opens the valves, and Hows through to the next pair. Before
the lower pair opens the first pair has closed thus insuring against the slightest
influx of air.
The operation of the improved machine is as follows:-
The dust and air enter the chamber 5 through the opening 2, and the air escapes
through the vent flue 3-4, passing through the perforations 30. The flour or dust
that is contained in the air, as it escapes through the vent flue settles on the inner
surface of the screen 6. The discharged air in the vent flue does not fill the whole
area but escapes in a ring about three inches thick on the outside edge of the air
flue, and the air rotates in a spiral whirl ascending with a centrifugal action so that
the dust that gets into this vent flue is thrown to the outside edge of this ring of air,
and, of course is impinged on the surface of the wire sieve and is forced through to
the inside of the space betwixt the imperforate and perforate walls of the vent flue,
where the air speed is reduced so that it is easier for the flour and dust to fall down
into the trough than it is for it to escape at the top of the vent flue. The revolving
brusbes or wipers force it through the meshes of the screen into the dead-air chamber 7,
where, there being no current of air, it settles and is deposited by the scraper 8
into the flue 19, which delivers it to the centre of the machine, from whence it falls
into the valves 25.
By encasing the brushes, the immediate surface being rubbed by them, is protected
from the action of the escaping air, and the flour or dust is prevented from being
carried out by the air current, and is forced by the brushes into the dead-air
chamber.
By the use of the cone or cylinder 22 a slower flow of air around the outer
cylinder is produced, so that the flour and dust will settle more readily than when
the outer surface is exposed to the full velocity of the air current.
The brushes 12 are rotary; that is, they are mounted on central pins or journals 50,
in which they turn as the shaft revolves and by making the brushes so as to turn on
their supports, as well as to revolve as a whole with the shaft, they are less liable to
become clogged by the flour, and better serve the purpose of forcing the flour through
the meshes of the screen.
It is possible that in some instances the brushes might be dispensed with, and the
air-current relied upon to force the flour or dust through the screen into the dead-air
chamber and, believing that we are the first to construct a machine having a dead-air
chamber in connection with a centrifugal dust collector, we do not wish to be confined
to the use of brushes in combination with the chamber.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what we
claim is
1. In a centrifugal dust collector in combination with an outer casing having a

page_text: tangential inlet, a screen and wall forming a dead-air chamber against which the
flour or dust is deposited under the action created by the inlet being tangential,
substantially as set forth.
2. In a centrifugal dust collector, in combination with an outer casing laving a
tangential inlet, a screen and wall forming a dead air chamber against which the
flour or dust deposited under the action created by the inlet being tangential and
brushes for forcing the flour or dust into the dead-air chamber substantially as
set forth.
3. In a dust collector in combination with an outer casing, having a tangential
inlet, a screen and wall forming a dead air chamber against which the flour or dust is
deposited under the action created by the inlet being tangential, and brushes rotating
on their axes bearing against the inner face of the dead air chamber and forcing the
material through the meshes, substantially as set forth.
4. In a dust collector, the combination of an outer casing having a tangential inlot
a wall and screen forming a dead air chamber, a central shaft, and encased brushes on
the shaft bearing against the screen and forcing the material through the meshes,
substantially as set forth.
5. In a centrifugal dust collector, the combination with the concentric outer casing,
a wall and a screen forming a dead air chamber in the outer part of the machine, of a
central shaft and adjustable brushes carried by the shaft and moving over said perforate
wall, said outer easing having tangential inlet, substantially as set forth.
6. In a centrifugal dust collector, the combination of an outer casing, provided with
an intet and with an outlet for purified air, a wall and screen forming an annular dead
air chamber located in the upper part of said casing and surrounding said air outlet, a
trough forming the bottom of the dead-air chamber a delivery spout and scrapers, said
casing having a tangential inlet; whereby the dust is separated from the air and
passes through said screen, substantially as set forth.
7. In a dust collector, the combination of an outer casing having a tangential inlot
and an outlet, an inner casing forming a vent-flue, and brushes, the lower end of said
vent-flue being perforated and the upper end having a wall and screen forming a
dead-air chamber, substantially as set forth.
8. In a dust collector the combination of an outer casing having a tangential inlet
and an outlet, an inner casing forming a vent flue, and encased brushes, the lower end
of said flue being perforated and the upper end having a wall and screen forming a
dead air chamber, substantially as set forth.
9. In a centrifugal dust collector, the combination with an outer casing, having a
tangential inlet, an inner casing forming a vent-flue and a screen forming an annular
dead-air chamber surrounding said flue, a trough forming the bottom of the dead-air
chamber, a delivery spout, and scrapers, substantially as set forth.
10. In a centrifugal dust collector, the combination of an outer casing, having
tangential inlet, an inner casing forming a vent-flue, a screen forming in connection
with said inner casing, an annular dead-air chamber, a trough forming the bottom of
the dead-air chamber, a delivery spout, a shaft, arms on the shaft, and scrapers on the
arms, substantially as set forth.
11. In a centrifugal dust collector, the combination of an outer cylinder having a
tangential inlet, an inner casing forming a vent flue, a screen forming in connection
therewith a dead-air chamber, a trough forming the bottom of the dead-air chamber, a
delivery spout, scrapers, and arms 21, for the purpose specified, substantially as set
forth.
12. In a centrifugal dust collector the combination of an outer casing having a
tangential inlet, an inner casing forming a vent-flue, a wall and screen forming a dead-
air chamber a trough forming the bottom of the dead-air chamber a central
shaft, arms on the shaft, scrapers on the arms and a shield 101; substantially as set
forth.
13. In a dust collector, the combination of an outer casing having a tangential
inlet, an inner casing forming a vent flue, a screen forming in connection with said

page_text: inner casing a dead-air chamber, encased cleaning brushes, and means for adjusting
the brushes consisting of dove-tailed blocks and set screws, substantially as set
forth.
14. In a dust collector, the combination of the outer casing having a tangential
inlet, an inner casing forming a vent-flue, a screen forming in connection with said
inner casing a dead-air chamber for catching the dust and rotary brushes 12 having
suitable journals and arranged within the vent-flue, substantially as set forth.
Dated this 13th day of August 1889.
WHITE & WOODINGTON,
27, Southampton Buildings, London, Agents for the Applicants.