Year: 1887

page_text: Date of Application, 4th June, 1997
Complete Left, 5th Mar., 1888
Complete Accepted, 1st June, 1888
I, LOUIS BENOIT FIECHTER of 82 Boswell Street, Liverpool, in the County of
Lancaster, Milling Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in that class of machines that are used in
flour mills to catch the dust that is removed from the stock in the process of manu-
facturing flour.
The dust catchers that are commonly used for this purpose are provided with a
dust-letaining cloth against which a current of dust-laden air is directed, the dust
being detained by the cloth while the air passes through and is discharged from the
machine.
In some instances dust catchers have been used in which the dust was separated by
gravity or centrifugal force.
The object of the invention is to provide an effective machine that will take the
dust-laden air as it is discharged from a middlings purifier or other machine and
separate the dust from the air without using any cloth or other air-straining medium.
Other objects of the invention will appear from the following detailed description.
In it we will first set forth Mr. Hardenbergh's original invention, and afterwards
describe Mr. Fiechter's modifications of same.

page_text: MR. HARDENBERGH'S PART OF THE INVENTION.
..
The current of dust-laden air is directed into an air trunk. The fan-spout which
leads from the fan of a middlings purifier is preferably so connected with the air
trunk that the dust-laden air from the exit side of the fan is discharged directly into
the air-trunk. This air-trunk is preferably of greater area in cross section than the
fan-spout so that it serves as an expansion-chamber in which the air-current is expanded,
and from which it passes into the separating chambers hereinafter described.
Connected with this air-trunk by suitable conductors are one or more cylindrical
upright separating chambers, preferably four in number, two arranged upon each side
of the air trunk.
The openings in the walls of the air-trunk are preferably of rectangular shape and
the air conductors between the air-trunk and the separating chambers are of similar
shape. Sliding valves are provided on the walls of the air-trunk that are adapted to
close, or partially close, the openings leading to the separating chambers.
These valves are connected to operating rods that extend through the end wall of
the air-trunk. All of the valves upon the same side of the air-trunk are preferably
connected to the same rod. By means of these rods the valves may be operated so as
to regulate the air-current passing into each cylindrical separating chamber.
The conductors are joined to the separating chambers near their upper ends and
preferably in a direction approaching a tangent to the cylinder, so as to direct the
current along the inner wall of the separating chamber and between it and the vent-
tube hereinafter described.
This is not essential however, as at whatever angle the conductor joins the sepa-
rating chamber the air-current will pass around in the annular space between the
wall of the separating chamber and the vent-tube.
The cylindrical chambers are provided with top and bottom walls having openings
as hereinafter set forth.
These chambers are preferably made of the same height as the air-trunk, and
the top and bottom walls of the latter. are extended across the chambers and
thereby form their top and bottom walls. This however is merely a detail of con-
struction that can be departed from if desired.
The top wall of the chambers are each provided with a central opening through
which a vent-tube extends downwardly into the chamber, its lower end being
below the inlet opening in the chamber.
The wall of the chamber is preferably covered with a spirally corrugated
cylinder which extends preferably from a point below the inlet opening to near the
bottom of the chamber.
If preferred the corrugations may be formed in the wall of the chamber
instead of in a separate covering.
If preferred the vent-tube may extend to the lower end of the corrugated
cylinder.
In the bottom of the cylindrical chamber is a dust discharge opening located near
the wall of the cylinder, and a central vent-opening. The vent opening is sometimes
provided with a slide having a series of holes of different sizes, and to arrange said
slide in ways on the bottom of the chamber. The slide is provided with a handle
by which it may be moved from over the vent opening or may be moved to bring
any one of its holes to register with the vent opening. By this means the area of the
vent opening may be varied at will. A. cone-shaped plate or canopy, whose hase is
of substantially the same diameter as the vent tube is placed beneath. This canopy
is fixed solid to the floor when no central dust discharge is used, otherwise it can
be secured at a short distance above the bottom of the chamber to suitable supports.
The side dust discharge opening may also be provided with a regulating valve
having a series of openings of various sizes, and a rod that projects through the
wall of the trough below, or the hopper as set forth in Mr. Fiechter's improvements,
by which the valve may be operated,

page_text: The bottom of the separating chamber may also have arranged on it a number of
thin strips of metal, about one inch in height, arranged in scroll form and extending
towards the side discharge opening. These strips are however not necessary.
Above
the cylindrical separating chambers is an expansion chamber, that extends preferably
over the four separating chambers, and into which all of the vent-tubes open. A
separate expansion chamber might if desired, be used with each cylindrical separating
chamber.
The top of the expansion chamber is provided with a series of slots through which
the air escapes from the chamber.
A series of deflectors are preferably arranged across the expansion chamber between
the vent-tubes and the slots. These deflectors are preferably formed by cutting a
series of slots from each edge of a sheet of metal towards its centre, leaving an uncut
portion at the centre, thus forming a series of fingers on each side of the uncut
portion of the plate, the fingers on one side of the plate being opposite the slots
on the other side. The fingers are then bent upward until they cross near the top.
The upper ends of the fingers are secured to the opposite sides of a bar which
extends through the walls of the chamber and is provided outside of the wall with
a handle. By means of this handle the bar may be turned and the dust shaken off
the deflectors. As the fingers forming the deflectors break joints with each other,
they break up any current of air that passes against them deflecting it, and causing it
to pass laterally between the fingers.
The parts of the machine already described constitute its essential elements, and
their operation is as follows:-
A current of dust laden air is blown into the expansion-chamber or air-trunk, and
thenco passes into the cylindrical separating chambers through the openings in the
wall of the air trunk and the conductors. The size of the air-trunk allows the current
to separate into several minor currents which enter the several cylindrical separating
chambers at the sides of the air-trunk..
As the annular space in each separating chamber is closed at the top the current
passes downward as it moves around in the chamber.
As it passes over the corrugated surface on the wall of the chamber the dust
which by centrifugal force is carried close to the wall of the chamber in the outer
portion of the current, enters the corrugations and its circular motion is stopped
and it slides down in them towards the bottom of the separating chamber. The
dust, is carried around in the lower part of the separating chamber and drops out
through the opening. The strips aid in directing the material to the opening.
As the air strikes the bottom of the separating chamber it is deflected upward and
its rotary motion tends to create a vacuum in the centre which would cause an
upward current of air through the central opening if such be used. This, however,
prevented by the canopy, which acts as a deflector and concentrator and gathers in
the air that rises under it deflecting it downward to the centre, and causing it to vent
through the central opening. The air that escapes through this opening is free
from dust and may pass into the mill. A part of the air rises above the canopy
and passes into the vent tube. As it does so it is expanded, loses nearly all of its
force and the greater part of the dust that is still carried by it drops down into the
top of the canopy below and is directed towards the wall at the bottom of the sepa-
rating chamber.
As the air passes out of the vent tube into the expansion chamber at the top it is
greatly expanded and the dust gradually settles in this chamber. The air passes
between the deflectors by which substantially all the dust remaining in it is removed,
and it finally escapes through the openings in the top of the expansion chamber.
The valve covering the openings in the walls of the air-trunk, and the valves in the
bottom of the separating chamber co-operate with each other. As the valves covering
the openings in the walls are moved to admit a greater or less amount of air to the
separating chambers, the other valves should also be moved to increase or diminish
the size of the openings in the bottom of the chamber.
Besides those features of the machine whose construction and operation have been

page_text: described, there are several other devices which may be considered as accessory to its
main parts, and which may be used to add to their efficiency.
These are as follows:-
-
The expansion chamber may be provided with a trough extending through it
centrally below its bottom. In this trough a spiral conveyor may be located. The
dust that accumulates in the expansion chamber may be swept into this trough from
which it will be discharged by the conveyor. When it is desired to sweep the dust
from the expansion chamber into the conveyor trough the deflectors may be turned up
by means of tho handles so as to permit the dust that has been taken out of the air by
the deflectors, to be brushed beneath the deflectors into the trough. To permit access
to the expansion chamber its top may be provided with one or more hinged covers.
If preferred a conveyor-trough may be arranged below the bottom of the air-trunk
and cylindrical separating chambers and extending partially across the bottoms of the
separating chambers, so that the side openings communicate therewith. A shaft is
located near each end of the conveyor-trough and is provided with sprocket-wheels.
Chains extend around these sprocket-wheels, and bars are secured to them. A spout
is arranged beneath an opening in one end of the conveyor-trough. One of the shafts
is provided with a suitable driving pulley.
This shaft being driven by any suitable means the bars are caused to sweep over the
bottom of the conveyor-box from one end to the other and discharge the dust there-
from through the spout.
This conveyor is not absolutely essential to the successful working of the machine,
and when preferred it may be omitted and suitable spouts may be arranged under the
side openings in the bottoms of the cylindrical separating chambers.
In some
instances an endless band of carpeting or other dust-detaining medium may be
arranged above the expansion chamber and over the slots in the top thereof. This
material will catch any remaining particles of dust that may escape through the slots
in the expansion chamber.
This band may be mounted at each end upon a shaft or roll which may be driven
by any suitable means.
It has been found however, that this band may be omitted in most instances as the
dust is generally all separated from the air before the air passes out of the expansion
chamber.
It has also been found that when the purifier fan discharges its air directly into the
air-trunk, there is back pressure caused by the air-current striking the opposite end
of the trunk, and that this back pressure interferes with the steady suction of the fan
through the cloth of the purifier.
This objection is obviated by providing a vent opening in the end wall of the air-
trunk. This opening may communicate directly through the wall of the air-trunk,
as little or no dust escapes through it, or it may be the open end of a conductor that
extends down the end wall and along the bottom of the air-trunk to its inlet end where
it connects with a pipe that may be connected with the purifier, and discharge the air
that escapes through it back into the purifier, or it may be connected with any other
suitable discharge-pipe.
This vent permits the discharge of a small portion of the air through it and thus
prevents the compression of the air in the end of the air-trunk and the consequent
backward pulsations resulting therefrom and affecting the operation of the fan.
The vent opening may be provided with a regulating-valve by means of which the
vent current inay he regulated.
The separating chambers may be in the form of prisms having five or more sides,
these forms are the equivalents of the cylindrical chambers.
The detail of construction of the several valves and operating devices may be
varied without departing from the invention.
Mr. Fiechter's modifications on Mr. Hardenbergh's aforesaid invention are as
follows:-
1st. In place of the rectangular top settling chamber, a large drum preferably
slowly revolving on a central axis can be used.

page_text: 2nd. A brush or scraper on the central axis revolves over the circular floor of the
drum.
3rd. A short radial spring door or counterweighted door is formed in said floor,
and a radial channel and creeper or worm provided below to automatically discharge
the dust. Pointed guards can deflect the dust brushed forward on the floor from
falling into the vents. Round the central hole in the top, concentric wire cones and
fingers, similar to those already described in Mr. Hardenbergb's original invention,
can be arranged conically concentrically round the cones. The top drun can be of
wire (sides and top) with impervious doors or openable casing so that the exit of air
can be regulated in every direction except downward. The bottom trough or chamber
can be replaced by a simple vertically conical hopper and the shaft forming the
central axis of the top drum can be extended through the air trunk, and this hopper,
and be provided with a creeper to prevent accumulation of material in the hopper, and
assist discharge.
Air pipes can be extended from the bottom hopper to the top drum to relieve the
pressure in the former.
Dated this 3rd day of June 1887
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicant.

page_text: In the accompanying drawings forming a part of this Specification,
Figure 1 is a partly sectional plan view of a machine embodying my invention.
Figure 2 is a sectional end elevation of the same.
Figure 3 is a sectional plan detail of the cylindrical chamber.
Figure 4 is a longitudinal vertical section on line -x of Figure 1.
Figure 5 is a similar view on line y-y of Figure 1.
In the drawings 2 represents an air trunk into which a current of dust-laden air is
directed. The fan spout as 4, which leads from the fan of a middlings purifier is
preferably connected with the air trunk 2, so that the dust laden air from the exit side
of the fan is discharged directly into the air trunk. This air-trunk is preferably. of
greater area in cross section than the fan spout, so that it serves as an expansion
chamber in which the air current is expanded, and from which it passes into the
separating chambers hereinafter described.

page_text: Connected with this air-trunk by suitable conductors 5 are one or more upright
separating chambers 3. preferably cylindrical. I have shown in the drawings four of
these separating chambers, two arranged upon each side of the air-trunk, and I consider
this the preferable arrangement.
The openings in the wall of the air-trunk are preferably of rectangular shape,
and the air-conductors 5 between the air-trunk and the separating chambers 3 are of
similar shape. I prefer to provide sliding valves 6 on the walls of the air-trunk that
are adapted to close or partially close the openings leading to the separating
chambers.
The valves 6 are connected to operating rods 3 that extend through the end wall
of the air-trunk. All the valves upon the same side of the air-trunk are preferably,
though not necessarily, connected to the same rod. By means of these rods the
valves may be operated so as to regulate the air-current passing into each cylindrical
separating chamber.
The conductors 5 are joined to the separating chambers near their upper ends and
preferably in a direction approaching a tangent to the cylinder, so as to direct the
current along the inner wall of the separating chamber and between it and the vent tube
hereinafter described.
I do not regard this as essential, however, as at whatever angle the conductor joins
the separating chamber the air current will pass around in the annular space between the
wall of the separating chamber and the vent tube, the air being directed by centrifugal
force against the wall of the separating chamber.
The cylindrical chambers are provided with top and bottom walls having openings
as hereinafter set forth.
I prefer to make these chambers of the same height as the air-trunk and to extend
its top and bottom walls across the chambers, and thereby form their top and bottom
walls, this, however is merely a detail of construction that can be departed from, if
desired.
The top walls of the chambers are each provided with a central opening through
which a vent tube 7 extends downwardly into the chamber, its lower end being below
the inlet opening in the chamber.
I also prefer to cover the wall of the chamber with a spirally corrugated cylinder 9,
which extends preferably from a point below the inlet opening to near the bottom of
the chamber. The corrugations need not necessarily be spiral, as they could be placed
vertically. Or the corrugated cylinder could be dispensed with entirely, as it is not
absolutely essential to the separation of the dust etcetera.
If preferred, the corrugations may be formed in the wall of the chamber instead of
in a separate covering.
If preferred, the vent tube may extend to the lower end of the corrugated
cylinder.
In the bottom of the cylindrical chamber is a dust discharge opening 18, located
near the wall of the cylinder, and a central vent opening 15. For the vent opening 15,
I prefer to provide a slide 17 having a series of holes 19, of different sizes, and to
arrange said slide in ways on the bottom of the chamber. The slide is provided with
a handle 21 by which it may be moved from over the vent opening 15, or may he
moved to bring any one of its holes to register with the vent opening 15. By this
means the area of the vent opening may be varied at will. Above the vent opening 15,
I arrange a cone-shaped plate or canopy 11, whose base is of substantially the same
diameter as the vent tube 7. This canopy is secured at a short distance above the
bottom of the chamber to suitable supports 12, one of which is shown on Figure 2,
or its base may rest on the bottom of the separating chamber.
The dust discharge opening 13 may also be provided with a regulating valve 14,
having a series of openings 15 of various sizes, and a rod 18 that projects through
the wall of the trough 39 by which the valve may be operated.
I may also arrange upon the bottom of the separating chamber, a number of thin
strips of metal 20, about one inch in height arranged in scroll form, and extending
towards the discharge opening 13. These strips need not be used, and I have shown

page_text: them only in Figure Above the cylindrical separating chambers is an expansion
chamber 23 that extends preferably over the four separating chambers; and into which
all of the vent tubes open. A separate expansion chamber might be used with
each cylindrical separating chamber, but I consider the arrangement shown to be
preferable. The expansion chamber may be rectangular or any other convenient shape.
The top of the expansion chamber is provided with a series of slots 25 through
which the air escapes from the chamber.
A series of deflectors 27 are preferably arranged across the expansion chamber
between the vent tubes and the slots 25.
These deflectors are preferably formed by cutting a series of slots from each edge of
a sheet of metal towards its centre, leaving an uncut portion at the centre, thus
forming a series of fingers on each side of the uncut portion of the plate, the fingers
on one side of the plate being opposite the slots on the other side. The fingers are
then bent upward until they cross near the top. The upper ends of the fingers are
secured to the opposite sides of a bar 29, which extends through the walls of the
chamber, and is provided outside of the wall with a handle 3; by means of this
handle the bar may be turned and the dust shaken off the deflectors. As the fingers
forming the deflectors break joints with each other, they break up any current
of air that passes against them, deflecting it, and causing it to pass laterally between
the fingers.
The parts of the machine already described constitute its essential elements, and
their operation is as follows:
A current of dust laden air is blown into the expansion chamber or air trunk 2,
and thence passes into the cylindrical separating chambers 3 through the openings in
the wall of the air trunk, and the conductors 5. The size of the air trunk allows the
current to separate into several minor currents, which enter the several cylindrical
separating chambers at the sides of the air trunk.
As the annular space in each separating chamber is closed at the top the current
passes downward as it moves around in the chamber.
As it passes over the corrugated surface on the wall of the chamber the dust, which,
by centrifugal force is carried close to the wall of the chamber in the outer portion of
the current, enters the corrugations, and its circular motion is stopped, and it slides
down in them towards the bottom of the separating chamber. The dust is carried
around in the lower part of the separating chamber, and drops out through the opening 13.
The strips 20 aid in directing the material to the opening. As the air strikes to the
bottom of the separating chamber it is deflected upward and its rotary motion tends to
create a vacuum in the centre which would cause an upward current of air through
the opening 15. This, however, is prevented by the canopy 11, which acts as a
deflector and concentrator, and gathers in the air that rises under it deflecting it
downward to the centre and causing it to vent through the opening 15. The air that
escapes through this opening is free from dust and may pass into the mill. A part of
the air rises above the canopy and passes into the vent tube. As it does so, it is
expanded, loses nearly all its force and the greater part of the dust that is still
carried by it, drops down into the top of the canopy below, and is directed towards
the wall at the bottom of the separating chamber.
As the air passes out of the vent tube into the expansion chamber at the top, it is
greatly expanded and the fine dust gradually settles in this chamber. The air passes
between the deflectors by which substantially all the dust remaining in it is removed,
and it finally escapes through the openings in the top of the expansion chamber.
The valves 6 covering the openings in the walls of the air-trunk 2 and the valves
in the bottom of the separating chamber co-operate with each other. As the valves 6
are moved to admit a greater or less amount of air to the separating chambers, the
other valves should also bo moved to increase or diminish the size of the openings in
the bottom of the chamber.
Besides those features of the machine, whose construction and operation have been
described, there are several other devices which may be considered as accessory to
its main parts, and which may be used to add to their efficiency.

page_text: These are as follows:
The expansion chamber may be provided with a trough 33 extending through it
centrally below its bottom. In this trough a spiral conveyor 35 may be located.
The dust that accumulates in the expansion chamber may be swept into this trough,
from which it will be discharged by the conveyor. When it is desired to sweep the
dust from the expansion chamber into the conveyor trough the deflectors may be
turned up by means of the handles, 31, so as to permit the dust that has been taken out
of the air by the deflectors to be brushed beneath the deflectors into the trough. To
permit access to the expansion chamber its top may be provided with one or more
hinged covers 37.
If preferred, a conveyor-trough 39 may be arranged below the bottom of the
air-trunk and cylindrical separating chambers and extending partially across the
bottoms of the separating chambers so that the openings 13 communicate therewith.
A shaft 41 is located near each end of the conveyor trough and is provided with
sprocket wheels 43. Chains 45 extend around these sprocket wheels, and bars 47
are secured to them. A spout 49 is arranged beneath an opening in one end of
the conveyor-trough. One of the shafts 41 is provided with a suitable driving
pulley 51.
This shaft being driven by any suitable means, the bars 47 are caused to sweep over
the bottom of the conveyor or box from one end to the other, and discharge the dust
therefrom through the spout 49.
I do not consider this conveyor essential to the successful working of the machine,
and when preferred it may be omitted, and suitable spouts may be arranged under the
openings 13 in the bottoms of the cylindrical separating chambers. In some instances,
an endless band 53 of carpeting or other dust dotaining medium may be arranged
above the expansion chamber as shown in Figure 4, and over the slots in the top
thereof. This material will catch any remaining particles of dust that may escape
through the slots in the expansion chamber.
This band may be mounted at each end upon a shaft or roll 55, which may be
driven by any suitable means.
I find, however, that this band may be omitted in most instances as the dust is
generally all separated from the air before the air passes out of the expansion
chamber.
I find also that when the purifier fan discharges its air directly into the air-trunk,
there is back pressure caused by the air-current striking the opposite end of the trunk,
and that this back pressure interferes with the steady suction of the fan through the
cloth of the purifier.
I obviate this objection by providing a vent opening 57 in the end wall of the air
trunk. This opening may communicate directly through the wall of the air trunk as
little or no dust escapes through it, or it may be the open end of a conductor 59 that
extends down the end wall and along the bottom of the air trunk to its inlet end,
where it connects with a pipe 61, that may be connected with the purifier and discharge
the air that escapes through it back into the purifier, or it may be connected with
any other suitable discharge-pipe.
This vent permits the discharge of a small portion of the air through it, and
thus prevents the compression of the air in the end of the air trunk, and the
consequent backward pulsations resulting therefrom, and affecting the operation of
the fan.
The vent opening 57 may be provided with a regulating valve 63 by means of
which the vent current may be regulated.
The separating chambers 3 may be in the form of prisms having five or more
sides, and I wish it to be understood as claiming these forms as the equivalents of the
cylindrical chambers. (Cylinders being used by preference, as being less expensive
and more efficient).
The detail of construction of the several valves and operating devices may be varied
without departing from my invention.
B

page_text: Mr. Fiechter's modifications on Mr. Hardenbergh's aforesaid invention are as
follows:-
Reference being had to the accompanying drawings in which,
Figure 6 is a sectional plan (on the line v v Figure 7) of the modified dust catcher.
Figure 7 is partly a vertical section on line xx, Figure 6, and partly an elevation.
Figure 8 is a sectional plan on line y-y, Figure 9.
Figure 9 is a vertical section on line, Figure 8, and in a plane at right angles
to Figure 7.
Figures 10 and 11 show a simplified form of automatic dust collector without moving
parts, Figure 10 being an elevation partly in section, and Figure 11 a transverse
section of the internal part of the apparatus on line -, Figure 10.
Figure 12 shows a vertical section of a modified form of lower expansion chamber
or dust collecting chamber.
Figures 13 & 14 show details of brush shaking mechanism being sectional elevation
and plan respectively.
A.
1st. In place of the rectangular top expansion chamber 23 (Figures 1 to 4) a large
cylindrical or conical chamber A. is provided in which the air may expand. The upper
portion of this chamber is formed of a cylindrical or conical drum A¹, which is
preferably stationary and slightly smaller in diameter than the chamber A. The
sides of the drum may be solid, but I prefer to cover them with wire gauze Cor
other filtering material. The whole or a portion of these perforated sides may be
covered by sliding ventilators or doors (Figure 7) by means of which the
expansion of the air in the drum A¹ and chamber A may be regulated, its escape
checked and the currents thereof directed against the deflectors hereinafter described.
Instead of the double row of deflecting fingers 27 (Figures 1 to 4) I employ the
following. Round the central hole in the top of the drum, and depending therefrom,
concentric wire gauze cones D are placed and fingers D' similar to the fingers 27 are
arranged conically and concentrically round the lower cone of the said cones.
central axle E extends from a point above the top of the drum A', through the air
trunk 2, and into a lower expansion chamber K, K, hereinafter described. The meshes
of the gauze C¹ or other filtering material on the sides of the drum A¹ are kept
constantly open by means of two vertical travelling brushes J, J, one on the inner,
and one on the outer side of the drum. Or, if preferred, only one brush may be used
either on the inside or outside. The brushes are carried by the radial arms J³, J4,
attached to the revolving central axle E, and suitably bent and stayed as shown in
Figure 9. The inner brush is encased in a casing J' and the dust from the gauze C¹
is led away into a shute J2, and is discharged therefrom at intervals as hereinafter
described. As seen in Figures 13 and 14 at each revolution of inner brush J, a
projection at the inner periphery of the drum A¹, comes in contact with a short arm jo
connected with the axis of brush thus turning the latter on its pivot, and giving it a
vigorous shaking by means of a spring behind the brush casing. This shaking
takes place preferably on the arrival of the brush at the trap door or valve of the
discharge hopper. The sides of the expansion chamber A are extended upwards, and
form an open annular trough J round which the lower end of the outer brush J
travels. The lower end of the arm Jacts as a scraper, carrying before it the dust,
(which is removed from the gauze by the outer brush, and settles in the trough J')
and discharging it, at each revolution of the arm down the shute Jo, into the hopper G,
hereinafter described. The outer brush J may also be provided with a separate casing
similar to J', and with shaking mechanisın such as, Ï³‚¸°³·
2nd. A scraper or brush F fixed to the lower side of the arm J³, rovolves with it
over the circular floor of the top expansion chamber A. This brush sweeps the dust
through a short radial spring or counterbalanced door, G, Figures 8 and 9 into the
discharge hopper G¹ which communicates by the shute G with the lower expansion
chamber K¹ or K. The brush or scraper may be placed radially to the axle E or
tangential to it, or to a circle concentric therewith. As the brush F approaches the
door G, the end of the quadrant F¹ carried by the brush or of the arm J³, pushes over

page_text: the counterweighted arm g' of the door G and causes the latter to open. The door
is held open by the quadrant and until the brush F has passed over the month of the
hopper and discharged the dust into it. As the brush approaches the edge of the
hopper, the hinged valve at the bottom of the shute J2, which had been previously
kept closed by being in contact with the floor of the expansion chamber, opens, and
discharges the dust from the shute into the hopper. The valve closes again on
striking the opposite edge of the hopper. The door G closes again as soon as the
rear end of the quadrant arm F¹ has released the counterweighted arm gl. Instead
of a flat door G as shown I may use a curved door which revolves with the counter
weighted arm gl. To prevent the dust being swept into the vent tubes 7,
counterweighted swing doors or guard plates H are provided at their upper ends.
The doors stand normally upright, so as to leave the vent tubes open.
brush F approaches one of them, a tappet or projection on its axis is pushed over
by the quadrant arm F¹ carried by the brush and the door closed. The arm F¹
sliding over the tappet h keeps the door closed until the brush has passed, when it
is released and falls open and remains steady by reason of its being counterweighted.
Instead of having the drum A' fixed, it may be made to revolve by any suitable
mechanism and the brush or brushes J may be stationary or may revolve on their
own or about the axis of the drum.
As the
3rd. The bottom dust trough or expansion chamber 39. (Figures 1-4) can be
replaced by a simple vertical conical chamber K as in Figure 12. The central
axle E which extends into this chamber can be provided with a creeper or worm E¹
to prevent accumulation of dust and to assist the discharge thereof. A great portion
of the dust and part of the air from the separating chambers 3 enter the chamber K
through the side vent opening 13. Here the air expands and deposits the dust
previously held in suspension by it. If preferred, a cylindrical chamber K¹,
Figures 7 and 9, may be substituted for the conical one K or any other convenient
form may be used. In the case of a conical chamber the creeper E¹ is replaced by a
flat revolving scraper E2, the dust being discharged into the trough K³. From this
trough it is collected by the worm K and discharged down the shute K³. The
worm K is carried by the shaft E³ which drives the central axle E by means of bevel
gear E. The pressure of the air in the chambers K or K' is relieved by the
ventilating tubes L which pass into the upper expansion chamber A. The relief
openings 57' are placed in the end of the air trunk 2. These prevent back pressure
in the air trunk and are each provided with a valve 63¹. As an additional means of
preventing back pressure, the air trunk is fitted at the rear end with deflecting walls 5',
which guide the dust laden air into the conductors 5 of the adjacent separating
chambers 3.
The air trunk 2 is also by preference made with a sliding bottom & which, when
withdrawn, deposits any dust that has settled thereon into the lower expansion
chamber K or K¹.
In Figures 10 and 11 a simplified form of dust catcher, without moving parts,
is shown. In this form I employ one or more vertical separating chambers M and N,
preferably cylindrical in shape. These are placed concentrically with each other and
with the enclosed vent tube O, their upper ends being closed as before and their
lower extremities provided with one or more dust discharge orifices QQ¹opening
into a lower dust collecting or expansion chamber R. The air trunk 2 com-
municates with the outer separating chamber M and it in its turn with the adjacent
separating chamber and so on with the entire series forming as it were continuous
spiral chamber B. The vent tube 0 opens into the upper expansion Camber S.
If desired one or more of the chambers M, N may be provided with spiral or other
corrugations such as 9.
The mode of action is as follows:-
The dust laden air enters through the air-trunk 2, and is directed downwards
assuming a gyrating motion. This motion as before causes a portion of the dust
to be carried against the outer walls of the chambers M and N.
The motion of the heavier particles contained in the current of air being thus

page_text: arrested, the said particles sink to the bottom of the chambers into the cones P and P'
whence they are discharged through the orifices Q and Q¹ into the lower expansion
chamber R. The air current after passing round the inner chamber N escapes through
the vertical vent tube O into the upper expansion chamber S being deflected by the
rings T, T, T, T, of the deflecting cone U, dislocating, as it were, in the process of
expansion, all suspended matter which remains in the air-current. This matter now
descends between the exterior of the chamber M and the .cylinder S into the
auxiliary dust chamber. R. The purified air finds an outlet through the central
opening V. The pressure in the dust chamber R is relieved as before by a ventilating
tube W, which leads the air against the lower end of the deflecting cone U.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, as partly communicated to me by
C. M. Hardenberg, I declare that what I claim is:
1st. In a dust catcher, the combination of an upright preferably cylindrical
separating chamber, having the inlet opening in its upper portion and a dust discharge
opening in its bottom, and an open vent tube extending downwardly into said
chamber, substantially as described.
2nd. In a dust catcher, the combination with an upright separating chamber having
an inlet opening near its top, a dust discharge opening in its bottom and preferably a
corrugated inner surface, of an open vent tube extending downwardly into said
chamber, substantially as described.
3rd. In a dust catcher, the combination with an upright separating chamber having
an inlet opening near its top and a dust discharge opening in its bottom, of an open
vent tube extending downwardly into said chamber, and of a cone-shaped plate
arranged in said chamber beneath the lower end of said vent tube, substantially
as described.
4th. In a dust catcher, the combination with an upright, separating chamber having
an inlet opening near its top, and a dust discharge opening in its bottom of an open
vent-tube extending downwardly into said chamber, and of an expansion chamber
into which the upper end of said vent tube opens, substantially as described.
5th. In a dust catcher, the combination with an upright separating chamber having
near its top an inlet opening, and having in its bottom a dust discharge opening near
its wall, and a central vent-opening, of an expansion chamber above said separating
chamber, and of an open vent-tube extending from said expansion chamber
downwardly into said separating chamber, substantially as described.
6th. In a dust catcher, the combination of an expansion chamber or air trunk, a
separating chamber or chambers connected with said air-trunk, an expansion chamber
above said separating chambers, and a vent tube extending from said expansion
chamber into each of said separating chambers, substantially as described.
7th. The combination, in a dust catcher of the air trunk 2, having one or more
openings in its wall a valve adapted to close each of said openings, a conductor such as 5
leading from each of said openings and one or more separating chambers such as 3,
each having a dust discharge opening and a central vent opening in its bottom,
provided with regulating valves, all substantially as described.
8th. In a dust catcher the combination with the separating chamber or chambers 3,
of the expansion chamber 23 having the openings 25 in its wall of the open vent
tube or tubes 7, extending from said expansion chamber into said separating chamber
or chambers and of the deflectors 27 arranged in said expansion chamber between
said openings 25 and said vent tube or tubes, substantially as described.
9th. The combination in a dust catcher, of one or more separating chambers as
described, with the air-trunk 2, connected with said chamber, and having the
described vent-opening 57 for the purpose set forth.
10th. The combination in a dust catcher, with the air trunk 2, of the separating
chambers 3 connected with said air trunk of the expansion chamber over said
separating chambers, and of the vent tubes extending from said expansion. chamber
into said separating chambers, substantially as described.

page_text: 11th. In a dust catcher, the combination with one or more upright preferably
cylindrical separating chambers, of an upper preferably cylindrical expansion chamber
communicating therewith, the upper part of which consists of a stationary or revolving
cylindrical drum, having its sides wholly or partly covered with wire gauze or other
filtering material, substantially as and for the purposes described.
12th. In a dust catcher, the combination with a drum (either stationary or
revolving) forming the upper portion of an upper, preferably cylindrical expansion
chamber, of one or more doors sliding over the perforated sides thereof, conical
concentric wire gauze deflecting cones suspended from the centre thereof and
deflecting fingers arranged concentrically with the said cones, substantially as and
for the purposes described.
13th. In a dust catcher, the combination with the central axle of a cylindrical
expansion chamber, of an approximately radial brush or scraper travelling over the
floor of said chamber and sweeping the dust through a suitable radial door into a
hopper or shute below, substantially as and for the purposes described.
14th. In a dust catcher, the combination with an approximately radial brush or
scraper travelling over the circular floor of a cylindrical expansion chamber of a
radial dust discharge door and one or more circular vent tube doors or guard plates
located in the said floor, and each automatically opened or closed as the brush
advances, substantially as and for the purposes described.
15th. In a dust catcher, the combination with the side vent or dust discharge
openings of one or more upright preferably cylindrical separating chambers of a lower
preferably conical or cylindrical expansion chamber located below the same, and
containing a revolving creeper or radial scraper for the purpose of removing the dust
therefrom, substantially as and for the purposes described.
16th. In a dust catcher, the combination with an upper expansion chamber, and a
lower expansion chamber of one or more ventilating tubes connecting the same, and
of one or more upright preferably cylindrical separating chambers communicating
with the said expansion chambers, the whole arranged substantially as and for the
purposes described.
17th. The simplified dust catching apparatus without moving parts, constructed
substantially as described and shown with reference to Figures 10 and 11.
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicant.