Improvements in Arresting and Collecting Dust in Flouring Mills and other like Places.
Year: 1896

page_text: Date of Application, 18th July, 1896
Complete Specification Left, 14th Apr., 1897-Accepted, 19th June, 1897
[Communicated from abroad by JOHN MURRAY CASE, of 410 Broadway, in the
City of Cincinnati, County of Hamilton and State of Ohio, United States of
America, Milling Engineer.]
Improvements in Arresting and Collecting Dust in Flouring Mills
and other like Places.
I, WILLIAM BOTTOMLEY, of 154 St. Vincent Street, Glasgow, Patent Agent,
do hereby declare the nature of this invention to be as follows:-
The invention relates to the method of and apparatus for arresting and collecting
the dust or finely divided particles usually carried in suspension in the air in mills
and other like places, or in the air coming from certain forms of milling machinery
or other machinery wherein the production of dust is one of the results of the
operation, and my invention consists primarily in passing the dust laden air through
a filtering wall made up of small parts which have pockets or spaces among them
when in mass, so that the suspended dust will be arrested by settling in such
pockets or spaces, or adhering to the component parts of the filtering material, and
then treating said filtering material at suitable intervals or in such manner that the
pockets or spaces will be broken up and the component parts agitated so as to
release the arrested dust and permit it to escape to a suitable means for collecting it,
after which the filtering material thus freed of the accumulation is continued in use
as a filtering medium.
For reasons which will appear hereinafter it is of the utmost importance to thus
provide for the continual re-use of the filtering material, and while my invention
consists firstly in the described method of arresting and collecting the dust, it
consists secondly in various embodiments of apparatus suitable for carrying out the
process en a commercial scale and in an economical and convenient manner.
According to one system of apparatus for carrying out my invention, I employ
suitably arranged and continually advancing body of filtering material through
which the dust laden air is caused to pass, and means whereby the material may be
received from the position or location in which it acts as a filtering medium, sifted
or otherwise agitated to separate the dust mingled therewith, and then returned
to the filtering position or location.
1, I represent a pair of stationary vertical screens formed of parallel walls the
spaces between them being open at top and bottom to permit the continuous
passage there through of a body of granular material, and closed at the ends by a
wall, 3 are outer screens parallel with screens I formed of a similar reticulated
material. The space between the walls 1 and 2 on each side of the apparatus
forms a passage which, in operation, is constantly filled with suitable granular
material such as wheat, corn, rye, or cotton seed, through which the said granular
material descends by gravity in continuous movement. This space communicates at
bottom with a pair of chutes 4, 4, extending horizontally from end to end of the
apparatus and converging to the centre in a longitudinal spout 5 extending from
end to end of the apparatus. Beneath this spout 5 and parallel therewith, at a
variable distance, is a horizontal board, the proximity of the said board 6 to the
bottom of the spout serving to regulate the discharge of the granular material
from the passage between the screen walls I and 3. On the horizontal board 6 is

page_text: mounted a web or rail 7 and these connected parts 6, 7, are hinged at one end in a
box 8 which is provided with a horizontal screen 9 so as to coustitute a shaking
Fieve for which purpose the box. 8 with its attached parts is suspended beneath
the fixed base frame 10 on which the entire apparatus is mounted by means of
pivotal hangers 11 of common form so pivoted to the stationary frame 10 and the
sieve box 8 as to permit a longitudinal shaking movement of the latter. The said
shaker 8 is further connected with the stationary base 10 by loose canvas 12 at
the sides and ends which permits the shaking of the sieve while preventing the
passage of air. The discharge of dust from the base beneath the screen is through
a suitable spout or aperture 13. The wheat is discharged from the top of the
shaking sieve 9, through a spout 14 into an elevator box 15 in which it is carried
by a bucket elevator 15 of common form to a spout 16 which returns it to the
top of the apparatus thus keeping the space between the vertical screens 1 and 3
and the space above them, constantly filled with moving granular material.
The dust laden air from the purifiers or other similar apparatus or any body of
air from which dust is to be collected is forced by a blast fan 17 for example, to
the dust separator through a trunk 17 delivering into the space between the
parallel screen walls 1, 1.
From the description thus far given of the apparatus the operation thereof in
collecting dust and discharging the air from which the dust has been recovered, will
be clearly understood. The blast by which the dust laden air is forced through
the trunk to the interior of the apparatus maintains a sufficient pressure of air
through the same by which the air is forced outward through the parallel screen
walls 1, 1, and the constantly moving body of wheat or other granular material on
the exterior thereof, the air escaping through the outer screen walls 3, 3, while the
dust is completely intercepted by the descending body of granular material
between the walls 1 and 3. The dust-laden wheat or granular material is
delivered upon the converging chutes 4, 4, on top of the longitudinal shaking
sieve 9, 9, by which sieve the dust is separated from the granular material,
descending to the box 8 below, from which it passes out through the dust spout or
aperture 13 to any suitable receptacle. From the description it will be understood
that the granular material is constantly moving in continuous and endless circuit
through the apparatus descending by gravity between the screen walls 1 and 3,
and returning by the elevator 15 to the top of the apparatus for re-use. The
shaking of the sifter 8, 9, is effected in the customary manner by a connecting
rod 18 attached at one end to the bottom of the sieve box 8 and at the other en I
to a crank 19 on a rotating shaft 20. To facilitate the discharge of the granular
material from the spout 5 to the surface of the sieve 9 the outer surface of the
discharge board 6 is corrugated or ribbed as shown in Fig. 4 to regulate the
discharge, the free end of the web or beam 7 on which said board is mounted, is
suspended by a regulating screw 21 from a suitable standard 22 on the sieve
box 8.
In a modification the apparatus is constructed with four instead of two parallel
screen walls 1, 3, through the vertical spaces between which the granular material
is constantly descending, the shaking sieve at bottom is dispensed with and the
granular material is returned to the top of the apparatus by an elevator 23 of
perforated metal or other material through the openings in which the dust is
discharged from the granular material as it is carried through in contact with the
inter surface thereof, under pressure due to gravity and the forcing action of the
elevating screw. The dust removed from the granular material is discharged
through a spout 25 and the granular material is continuously returned to the top
of the apparatus as before, descending through the space between the screen walls
through which the air is forced by pressure of the blast so that the granular
material by which it is caught and separated from the air moves, as before, in a
constant and endless circuit. It is apparent that the body of the screens may be
made of circular, hexagonal, or any other form, but I prefer the rectangular form
as most convenient to construct.

page_text: In another modification the screen walls are made similarly to the parallel
walls 1 and 3, but the shaking sieve is dispensed with, the granular material being
discharged upon a shaker 8 which delivers the dust-laden granular material to
the case 25 of a rotary fan 26 from which rises in vertical tangential position a
spout 27 curved into horizontal position at top to return the wheat or other
granular material to the top of the apparatus as before and having a perforated
outer wall 27 through the perforations in which the dust is discharged from the
wheat or granular material as the latter is thrown up by its own momentum
produced by the centrifugal action of the rotary fan 26. The perforate wall 27
is covered at a suitable distance with an imperforate casing 28 between which
and the perforated wall 27 is formed a chute or passage through which the dust
descends and from which it is discharged by a spout 29.
In another modification, the apparatus is constructed as first described excepting
that the shaking sieve 8, 9, and its accessories, are dispensed with and the dust-
laden granular material is delivered at bottom to a screw conveyor 30 working in
a stationary semi-cylindrical screen 31 through which the dust is separated from
the granular material, the latter being delivered by a screw conveyor to the
elevator 15 while the dust is discharged by another screw conveyor through the
dust spout 13.
According to another system of apparatus for carrying out my invention, I locate
an agitator in the filtering wall so as to agitate the component parts of the filtering
material and release the arrested dust, without removing the material as heretofore.
In order to avoid interrupting the continuity of the process the greater part of the
filtering wall is left at all times intact, the agitator being confined in its operation
at any time given, to a very small portion of the filtering body, and in order that
all parts of the filtering body may be relieved of the arrested dust as often as
necessary, a relative movement is produced between the agitator and the body of
filtering material, either by moving the agitator while the body of material remains
stationary, or by retaining the agitator in a fixed position and moving the body of
filtering material. The relative movement is comparatively slow and the agitator
is preferably such that it makes its way through the body of material, as the
relative movement takes place, by causing the material in its immediate vicinity to
feed past it.
This has the effect of breaking up the pockets in which the dust has
been arrested and permitting the air to blow out the arrested dust. It remains
necessary only to provide for catching the dust which is thus constantly being
blown out along the restricted line of the agitator, when the operation of collecting
the dust is complete. This is easily arranged by the employment of a shield which
covers a sufficient portion of the filtering wall, directly over and adjacent to the
agitator, to catch all dust which is released and blown through. Inasmuch as all
of the filtering material is continuously subjected to treatment by the agitator, but
a restricted line of material being treated at any one time while all the rest of it
remains intact for arresting and collecting process is complete and continuous.
My present invention is capable of wide application. It is well adapted for use
in connection with the cyclone" type of machine and when thus applied, it will
permit the settlement by gravity of all the heavier particles and then thoroughly
remove from the air, all the finer particles which generally escape in that type of
machine. In applying the invention to this type of machine I may either locate
the filtering medium together with its agitator directly in the walls of the vortex
chamber, or I may employ separate filtering walls which will fit over the escape
opening of the ordinary cyclone machine and treat the air escaping therefrom, to
remove the dust which ordinarily returns to the atmosphere of the mill or is
wasted.
1 represents a settling drum into which air may be introduced through a
tangential opening. 2, to produce a centrifugal separation of the heavier particles
from the dust-laden air. 3 is a shaft mounted centrally within the drum 1 and
carrying the fan motor 4 in position to receive the impact of the current of air
and imparting a rotary movement to the shaft 3. 5 is a sweep carried by the

page_text: shaft 3 and adapted to collect the heavier particles of material which escape from
the air by vertical action and to discharge said particles through a spout 6. The
chamber 1 has an end opening 7. In so much of the machine there is nothing
particularly novel.
Mounted over the cylinder 1, and in position to receive the air which escapes
therefrom, is a filtering chamber 8 formed with double walls 9 and 10, the space
between which is filled with a filtering material 11. The walls 9 and 10 are
perforated and the air which rises out of the cylinder 1, escapes through such
perforations and finding its way through the small pockets or interstices between
the component parts of the filtering material, passes to the outside. Any dust,
however fine, which is suspended by the current of air lodges in the pockets between
the component parts of the material and is there arrested. 12 is a sweep carried
by the upper portion of the shaft 3 which extends through the chamber 8 and
serves to sweep from the inner surface of the wall 9, those particles which adhere
to said wall and at the same time prevents clogging of the perforations in said
wall.
13 is an agitator mounted upon a shaft 14 whose upper end turns in a bracket 15
while its lower end carries a friction roller 16 which fits in the space between the
walls 9 and 10. A bevel-gear 17 on shaft 14, meshes with a bevel-gear 18 on a
drive shaft 19, and thereby transmits rotary movement from the said shaft 19 to
the shaft 14. The shaft 19 is mounted in brackets 20 and has a driving pulley 21.
22 represents a shield which corresponds in position to the agitator 13 and covers
the portion of the wall 11 which is opposite said agitator so that the air which
escapes at this point is directed down and out at a spout 23. The agitator 13 is
such that it stirs up or agitates the component parts of the filtering material and
breaks up the pockets in which the dust had lodged, so that the air passing through
the filtering wall along the line of the agitator, carries with it the dust which has
from time to time lodged among the particles of filtering material and escaping
into the shield 22, may be collected at the spout 23. The construction of the
agitator 13 is also such that by its rotation the material adjacent to it is gradually
fed along, so that if a relative movement is produced between the agitator and the
whole body of the filtering material, all of such material will gradually come to be
treated by the agitator, and thus relieved of all the dust accumulated in it and
passed on to repeat the operation of arresting the dust. It will be seen that the
agitator only disturbs the material in its immediate vicinity and that as this is only
a very small section of the material, the main body of the filtering wall is at all
times ready for the passage of the dust-laden air and in condition to arrest the
dust.
In order to produce the relative movement necessary to bring all parts of the
filtering wall successively under the cleansing influence of the agitator, the machine
has means for continually advancing the body of material while the agitator remains
stationary. To accomplish this purpose, the chamber 8 is supported by balls 24
upon the cylinder 1 whereby it may readily turn thereon, and the shaft 19 carries
an eccentric 25 which operates a pawl 26 resting upon the ratchet-edge 27 of the
outer wall 10 so that for each revolution of the shaft 19, the chamber 8 with its
contents will be advanced slightly so as to bring a new portion of the filtering
material constantly within reach of the agitator.
I may have a form of machine made on the basis of the borizontal cylinder 8
having double perforated walls 9, 10ª containing the filtering material 11, and
receiving the dust-laden air through a tangential inlet 2", while the heavier particles
which settle by centrifugal force, escape through the spout 6, 13, 13, are two
agitators meshing by gears 174, 17", on their shafts and the gears 18", 18" on a
shaft 19 so as to receive motion from a pulley 21ª. 4 represents a fan motor upon
the hollow shaft 30 so as to assist in imparting rotary movement to said shaft,
and 12 are sweeps carried by said shaft for keeping the inner faces of the cylinder
Lead clear. 22, 22", are shields which are carried by hollow shaft 30 so as to be
held in position over the agitators 13 and to receive the dust dislodged by said

page_text: agitators and deliver the same into the hollow shaft 30 from whence it escapes
through a spout 31. By reason of the nature of the gearing 17, 18, and of the
action of the air upon the fan motor 4, a slow rotary motion is imparted to said
shaft 30 together with all the parts carried by it, said motion being governed by
the feeding action of the agitator 13 as hereinbefore explained. The result is that
while the walls 9" and 10" together with the enclosed material 11 remains stationary
the agitator 13 will gradually pass around through said material and treat all the
parts of it successively and at a time while leaving the remainder in condition to
arrest the dust, from the air which is passing through the walls, 32, 32, are staal-
pipes through which material is introduced and which may be kept filled to take
the place of wear and keep the material under proper pressure and packed condition
in the machine.
The machine may be adapted to be mounted over an ordinary cyclone dust
catcher. The dust catcher is represented by 33, and its axial opening at 34.
35 represents a conical chamber formed of double perforated walls 9, 10,
having the space between them filled with the filtering material 11. 36 represents
a shaft which carries a fan motor 4b in the settling chamber 33 and an angularly
arranged sweep 37 in the chamber 35. On its upper end, the shaft carries gear
wheel 38 and a drive pulley 39. 40 is a casting which fits in a socket 41 so as to
be adapted to turn in the upper end of the chamber 35, and this casting carries the
agitator 13 located between the walls of the chamber and the shield 22 which
hangs down over the outer wall of the chamber in position corresponding to the
agitator 13. By the nature of the connection between the agitator 13 and the
shaft 36, and the feeding action of the said agitator, the casting 40, together with
the parts carried by it, slowly travel around the cone-shaped chamber 35.
42 represents a trip valve which normally closes the lower end of the shield 22b so
as to prevent the escape of the dust, but which is engaged and opened by a
prejection 43, each time the shield 22 comes opposite a fixed spout 44. 45 is a
spout leading from the flor of the conical chamber and serving to deliver it into
the spout 44, the material which settles in chamber 35.
In another modification I provide an upper centrifugal sifting chamber 50, having
a tangential inlet 51 for the dust-laden air and a spouted outlet 52 for escape of
heavier particles which are separated by centrifugal force, and beneath the eye of
the settling chamber, is chamber 53 having a rotatable drum 54 with a single per-
forate bottom 55 upon which rests a body of filtering material 11. The air escaping
from chamber 50, passes downward through filtering material 11 and all remaining
dust is arrested. 56 is an agitator comprising a rake pivoted by its back at 57, and
receiving a rocking motion from an arm 58 engaged by crank 59 of shaft 60, which
is rotated by pulley 61. The rocking movement thus imparted to the rake, agitates
the filtering material sufficiently to permit the escape of arrested dust from the
restricted area of agitation while the major part of the material remains in condition
to arrest the dust from the escaping air, and the arrested dust which is dislodged by
agitator 56, is collected in shield 22° and discharged through spout 62, by the worm 63
on shaft 60. A pawl 64 on the agitator 56, engages a peripheral ratchet 65 on
the drum 54 and each time the agitator vibrates, advances the drum by the space
of one tooth. By this means the entire body of filtering material is brought under
the cleansing action of the agitator from time to time while the operation of
arresting the dust goes on uniuterrupted. 66 is the turning post of the drum,
stepped in the bearing 67, and carrying at its upper end a swivel bearing 68 for the
agitator. 69 is a packing closing the crack between drum 54 and the wall of
chamber 53.
My invention as above explained, involves the continuous use of the same
body of granular material, which is passed in a continuous circuit through the
machine, collecting the dust from the dust-laden air discharging the purified air,
then discharging the dust then carrying back, for re-use, the granulated material
from which the dust has been sifted out. The same body of wheat or other
granular material may thus be used over and over for many months, and for

page_text: an indefinite period, and when it is desirable to replace, or to renew it, the used
wheat or other granular material may be drawn out by means of a slide 33, and a
new supply may be introduced at top, through a spout or hopper 34.
By "granular material" as is used in the specification, I do not limit myself to
grain of any particular kind, or to any material of substantially similar shape, but
desire to cover by such term, any material made up of small particles which if
delivered in mass into the space which defines the filtering wall, will form small
spaces or pockets through which the air may pass and in which the dust or
substance carried by the air, will lodge or otherwise be arrested by coming in
contact with the surfaces of the particles which go to make up the intercepting
wall. It is found in practice to be of utmost importance to provide for a repeated
use of the same body of granular material, for arresting the dust, for without
this feature, the device would be impracticable, owing to the requirement of fresh
material is always impregnated with dirt and foul substances which would become
mingled with the arrested dust and thus render useless the product obtained by the
dust catcher for anything more valuable than feed. In all profitable mills where
close yield is obtained, the dust from the purifiers, which it is intended to collect
by my present apparatus, is bolted, and the flour and middlings separated and
made into a second grade flour which is worth much more than feed. Hence
it is of greatest importance that the material arrested by the dust catcher, should
be kept free from the foul matter which is always present in fresh granular
material. By the continual or repeated use of the same wheat or granular
material, the latter becomes at once freed from foul substances, and hence there
can be no deterioration of valuable' products which are arrested by passing_the
dust-laden air through the continuously returning mass, of such material. The
idea of continually returning the granular material to the filtering wall is therefore
of vital importance. By suitably advancing the granular material, the component
parts of the filtering medium are continually sifted so that new and unobstructed
pockets are continually being formed and the filled pockets continually pass off to
be emptied of the arrested dust. By delivering the dust-laden air into the
chamber by means of an air blast, the heavier particles are precipitated by the
force of the blast and pass to the separating device below without coming into
contact with the filtering wall, thus materially increasing the capacity of the
machine, the filtering capacity being limited by the quantity of material which
will be received by the pockets which form in the granular material.
A further very important result obtained from the continuous use of the same
material with the intervening mechanism which continuously removes the arrested
matter therefrom, is that a macbine is produced which is a complete automatic
entity in itself and is not dependent in the performance of its functions upon
association with other mechanism, for the supply of some material feature to its
operation.
My invention is of great utility for purifying the air in mills and other
establishments. By the use of fans, taking the dust-laden air at one or more
points, passing it through my apparatus and discharging the purified air therefrom
at another distant point or points the entire atmosphere of the mill may be relieved
of dust, which is a constant source of danger, in causing explosions and is also
highly prejudicial to health.
Dated thin 17th
1000
BOTTOMLEY & LIDDLE,
154 St. Vincent Street, Glasgow, Applicant's Agents.

page_text: Improvements in Arresting and Collecting Dust in Flouring Mills
and other like Places.
I, WILLIAM BOTTOMLEY of 154, St. Vincent Street, in the County of the City
of Glasgow, North Britain, 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 :-
The invention relates to the method of and apparatus for arresting and collecting
the dust or finely divided particles usually carried in suspension in the air in mills
or other like places, or in the air coming from certain forms of milling machinery
or other machinery wherein the production of dust is one of the results of the
operation, and my invention consists primarily in passing the dust-laden air through
a filtering wall made up of small parts which have pockets or spaces among then
when in mass, so that the suspended dust will be arrested by settling in such
pockets or spaces, or adhering to the component parts of the filtering material, an!
then treating said filtering material at suitable intervals or in such manner that the
pockets or spaces will be broken up and the component parts agitated so as to
release the arrested dust and permit it to escape to a suitable means for collecting
it, after which the filtering material thus freed of the accumulation is continued in
use as a filtering medium."
For reasons which will appear hereinafter it is of the utmost importance to thus
provide for the continual re-use of the filtering material, and while my invention
consists firstly in the described method of arresting and collecting the dust, it
consists secondly in various embodiments of apparatus suitable for carrying out the
process on a commercial scale and in an economical and convenient manner.
According to one system of apparatus for carrying out my invention, I employ a
suitably arranged and continually advancing body of filtering material through
which the dust-laden air is caused to pass, and means whereby the material may be
received from the position or location in which it acts as a filtering medium, sifted
or otherwise agitated to separate the dust mingled therewith, and then returned to
the filtering position or location. This is conveniently arranged in one of the
different ways illustrated by Sheets 1, 2, 3 of the accompanying drawings,
wherein
Figure 1 is a side elevation of a suitable apparatus embodying this principle.
Figure 2 is a vertical transverse section of the same.
Figure 3 is a plan view thereof.
Figure 4 is a detail sectional elevation on a larger scale illustrating a mode of
graduating the discharge of the granular material, from the screening device where
it is charged with dust, to the separator where the dust is sifted out of it and from
which the granular material is again elevated for re-use as above stated.
Figure 5 is a vertical section of the apparatus in a modified form.
Figure 6 is a horizontal section of the apparatus shown in Fig. 5.
Figure 7 is an elevation of the apparatus partly in section illustrating another
modification.
Figure 8 is an elevation partly in section showing still-another modification.
Figure 9 is a vertical section on a plane at right angles to that shown in Fig. 8,
showing the sifting and dust discharging device at the lower part of the
apparatus.
In Figs. 1 and 2, 1, 1 represent a pair of stationary vertical screens formed of
parallel walls the spaces between them being open at top and bottom to permit the
continuous passage there through of a body of granular material, and closed at the

page_text: ends by a wall 2. 3, 3 are outer screens parallel with screens 1, 1 formed of similar
reticulated material. The space between the walls 1 and 2 on each side of the
apparatus forms a passage which, in operation, is constantly filled with suitable
granular material such as wheat, corn, rye, or cotton seed, through which the said
granular material descends by gravity in continuous movement.
This space
communicates at bottom with a pair of chutes 4, 4, extending horizontally from
end to end of the apparatus and converging to the centre in a longitudinal spout 5
extending from end to end of the apparatus. Beneath this spout 5 and parallel
therewith, at a variable distance, is a horizontal board, the proximity of the said
board 6 to the bottom of the spout 5 serving to regulate the discharge of the
granular material from the passage between the screen walls 1 and 3. On the
horizontal board 6 is mounted a web or rail..7-and-these connected parts 6, 7, are
hinged at one end in a box 8 which is provided with a horizontal screen 9 so as to
constitute a shaking sieve for which purpose the box 8 with its attached parts is
suspended beneath the fixed base frame 10 on which the entire apparatus is
mounted, by means of pivotal hangers 11 of common form so pivoted to the
stationary frame 10 and the sieve box 8 as to permit a longitudinal shaking
movement of the latter. The said shaker 8 is further connected with the stationary
base 10 by loose canvas 12 at the sides and ends which permits the shaking of the
sieve while preventing the passage of air. The discharge of dust from the base
beneath the screen is through a suitable spout or aperture 13. The wheat is
discharged from the top of the shaking sieve 9, through a spout 14 into an elevator
box 15 in which it is carried by a bucket elevator 15 of common form to a spout 16
which returns it to the top of the apparatus thus keeping the space between the
vertical screens 1 and 3 and the space above them, constantly filled with moving
granular material.
The dust-laden air from the purifiers or other similar apparatus or any body of
air from which dust is to be collected, is forced by a blast fan 17" for example, to
the dust separator through a trunk 17 delivering into the space between the parallel
screen walls 1, 1.
From the description thus far given of the apparatus the operation thereof
in collecting dust and discharging the air from which the dust has been recovered,
will be clearly understood. The blast by which the dust-laden air is forced
through the trunk to the interior of the apparatus maintains a sufficient pressure of
air through the same by which the air is forced outward through the parallel
screen walls 1, 1, and the constantly moving body of wheat or other granular
material on the exterior thereof, the air escaping through the outer screen walls, 3, 3,
while the dust is completely intercepted by the descending body of granular
material between the walls 1 and 3. The dust-laden wheat or granular material is
delivered upon the converging chutes 4, 4, on the top of the longitudinal shaking
sieve 9, 9, by which sieve the dust is separated from the granular material,
descending to the box 8 below, from which it passes out through the dust spout or
aperture 13 to any suitable receptacle. From the description it will be understood
that the granular material is constantly moving in continuous and endless circuit
through the apparatus descending by gravity between the screen walls 1 and 3, and
returning by the elevator 15 to the top of the apparatus for re-use. The shaking
of the sifter 8; 9, is effected in the customary manner by a connecting rod 18
attached at one end to the bottom of the sieve box 8 and at the other end to a
crank 19 on a rotating shaft 20. To facilitate the discharge of the granular
material from the spout 5 to the surface of the sieve 9 the outer surface of the
discharge board 6 is corrugated or ribbed as shown in Fig. 4 and to regulate the
discharge, the free end of the web or beam 7 on which said board is mounted, is
suspended by a regulating screw 21 from a suitable standard 22 on the sieve
box 8.
In the modification illustrated in Figs. 5 and 6, the apparatus is constructed with
four instead of two parallel screen walls 1, 3, through the vertical spaces between
which the granular material is returned to the top of the apparatus by a screw

page_text: elevator 23 working in a vertical shaft 24 of perforated metal or other material
through the openings in which the dust is discharged from the granular material
as it is carried through in contact with the inner surface thereof, under pressure
due to gravity and the forcing action of the elevating screw. The dust removed
from the granular material is continuously returned to the top of the apparatus as
before, descending through the space between the screen walls through which the
air is forced by pressure of the blast so that the granular material by which it is
caught and separated from the air moves, as before, in a constant and endless
circuit. It is apparent that the body of the screens may be made of circular,
hexagonal, or any other form, but I prefer the rectangular form as most convenient
to construct.
In the modification shown in Fig. 7 the screen walls are made similarly to the
parallel walls 1 and 3 in Figs. 1 and 2, but the shaking sieve is dispensed with, the
granular material being discharged upon a shaker 8 which delivers the dust-laden
granular material to the case 25 of a rotary fan 26 from which rises in vertical
tangential position a spont 27 curved into horizontal position at top to return the
wheat or other granular material to the top of the apparatus as before and having
a perforated cuter wall 27 through the perforations in which the dust is discharged
from the wheat or granular material as the latter is thrown up by its own
momentum produced by the centrifugal action of the rotary fan 26. The
perforated wall 27" is covered at a suitable distance with an imperforate casing 28.
between which and the perforated wall 27 is formed a chute or passage through
which the dust descends and from which it is discharged by a spout 29.
In the modification illustrated in Figs. 8, and 9, the apparatus is constructed as
described with reference to Figs. 1 and 2, excepting that the shaking sieve 8, 9,
and its accessories, are dispensed with and the dust-laden granular material is
delivered at bottom to a screw conveyor 30 working in a stationary semi-cylindrical
screen 31 through which the dust is separated from the granular material, the latter
being delivered by a screw conveyor to the elevator 15 (Figs. 1 and 2) while the
dust is discharged by another screw conveyor through the dust spout 13.
According to another system of apparatus for carrying out my invention, I locate
an agitator in the filtering wall so as to agitate the component parts of the filtering
material and release the arrested dust, without removing the material as heretofore.
In order to avoid interrupting the continuity of the process the greater part of the
filtering wall is left at all times intact, the agitator being confined in its operation
at any given time, to a very small portion of the filtering body, and in order that.
all parts of the filtering body may be relieved of the arrested dust as often as
necessary, a relative movement is produced between the agitator and the body
of filtering material, either by moving the agitator while the body of material
remains stationary, or by retaining the agitator in a fixed position and moving
the body of filtering material. The relative movement is comparatively slow
and the agitator is preferably such that it makes its way through the body of
material, as the relative movement takes place, by causing the material in its
immediate vicinity to feed past it. This has the effect of breaking up the
pockets in which the dust has been arrested and permitting the air to blow out
the arrested dust. It remains necessary only to provide for catching the dust
which is thus constantly being blown out along the restricted line of the agitator,
when the operation of collecting the dust is complete. This is easily arranged
by the employment of a shield which covers a sufficient portion of the filtering
wall, directly over and adjacent to the agitator, to catch all dust which is released
and blown through. Inasmuch as all of the filtering material is continuously
ubjected to treatment by the agitator, but a restricted line of material being
reated at any one time while all the rest of it remains intact for arresting the
lust, it will be seen that the dust arresting and collecting process is complete
nd continuous.
My present invention is capable of wide application. It is well adapted for
se in connection with the "Cyclone" type of machine and when thus applied,

page_text: it will permit the settlement by gravity of all the heavier particles and then
thoroughly remove from the air, all the finer particles which generally escape
in that type of machine. In applying the invention to this type of machine I may
either locate the filtering medium together with its agitator directly in the walls
of the vortex chamber, or I may employ separate filtering walls which will fit
over the escape opening of the ordinary cyclone machine and treat the air escaping
therefrom to remove the dust which ordinarily returns to the atmosphere of the
mill or is wasted.
Another system of machines embodying my invention will be fully understood
upon reference to Sheets 4, 5 and 6, wherein -
and
Figure 1 is a vertical axial section of one embodiment of my present invention,
Figure 1 is a detail vertical section on the line a, a Fig. 1.
Figures 2 and 3 are respectively a vertical axial section and an elevation of
another embodiment of my said invention.
Figure 4 is a vertical axial section of another form embodying the invention, this
figure illustrating the application. of the invention to an ordinary cyclone dust-
catcher, and
Figure 4 is a modified form of the agitator which may be employed in Fig. 4
when the dust arresting material is of a fibrous nature.
Figures 5 and 6 are respectively a top plan of the form of machine shown in
Fig. 4 and a horizontal section through such a machine, the plane of section being
indicated by the line 2, 2, Fig. 4.
Figures 7 and 8 are a vertical diametric section and a detail view of another
form.
Referring to Figs. 1 and 14, 1 represents a settling drum into which air may be
introduced through a tangential opening 2, to produce a centrifugal separation
of the heavier particles from. the dust laden air. 3 is a shaft mounted centrally
within the drum. 1 and carrying the fan motor 4 in position to receive the
impact of the current of air and imparting a rotary movement to the shaft 3. 5 is
a sweep carried by the shaft 3 and adapted to collect the heavier particles of
material which escape from the air by vertical action and to discharge said particles
through a spout 6. The chamber I has an end opening 7. In so much of the
machine there is nothing particularly novel. Mounted over the cylinder 1, and in
position to receive the air which escapes therefrom, is a filtering chamber 8 formed
with double walls 9 and 10 the space between which is filled with a filtering
material 11. The walls 9 and 10 are perforated and the air which rises out of the
cylinder 1, escapes through such perforations and finding its way through the small
pockets or interstices between the component parts of the filtering material,
passes to the outside. Any dust, however fine, which is suspended by the current
of air lodges in the pockets between the component parts of the material and
is there arrested. 12 is a sweep carried by the upper portion of the shaft 3 which
extends through the chamber 8 and serves to sweep from the inner surface of the
wall 9, those particles which adhere to said wall, and at the same time prevents
clogging of the perforations in said wall.
13 is an agitator mounted upon a shaft 14 whose upper end turns in a bracket 15
while its lower end. carries a friction roller 16 which fits in the space between the
walls, 9 and 10.. A bevel-gear 17 on shaft 14, meshes with a bevel-gear 18 on a
drive shaft 19, and thereby transmits rotary movement from the said shaft 19 to
the shaft 14. The shaft 19 is mounted in brackets 20 and has a driving pulley 21.
22 represents a shield which corresponds in position to the agitator 13 and covers
the portion of the wall 11 which is opposite said agitator so that the air which,
escapes at this point is directed down and out at a spout 23. The agitator 13 is
such that it stirs up or agitates the component parts of the filtering material and
breaks up the pockets in which the dust has lodged, so that the air passing
through the filtering wall along the line of the agitator, carries with it the dust
which has, from time to time lodged among the particles of filtering material

page_text: and escaping into the shield 22, may be collected at the spout 23. The construction
of the agitator 13 is also such that by its rotation the material adjacent to it is
gradually fed along, so that if a relative movement is produced between the
agitator, and the whole body of the filtering material, all of such material will
gradually come to be treated by the agitator, and thus relieved of all of the dust
accumulated in it and passed on to repeat the operation of arresting the dust.
It will be seen that the agitator only disturbs the material in its immediate vicinity
and that as this is only a very small section of the material, the main body of the
filtering wall is at all times ready for the passage of the dust-laden air and in
condition to arrest the dust.
In order to produce the relative movement necessary to bring all parts of the
filtering wall successively under the cleansing influence of the agitator, the form
of machine shown in Fig. 1 has means for continually advancing the body of
material while the agitator remains stationary. To accomplish this purpose, the
chamber 8 is supported by balls 24 upon the cylinder 1 whereby it may readily
turn thereon, and the shaft 19 carries an eccentric 25 which operates a pawl 26
resting upon the ratchet edge 27 of the cuter wall 10 so that for each revolution
of the shaft 19, the chamber 8 with its contents will be advanced slightly so as
to bring a new portion of the filtering material constantly within the reach of the
agitator.
In Figs. 2 and 3 is shown a form of machine made on the basis of the horizontal
cylinder 8 having double perforated walls 9, 10 containing the filtering
material 11, and receiving the dust-laden air through a tangential inlet 2", while
the heavier particles which settle by centrifugal force, escape through the spout 6".
13, 13, are two agitators similar to that described in Fig. 1 and meshing by
gears 17, 17" on their shafts and the gears 18", 18" on a shaft 19 so as to receive
motion from a pulley 21. 4 represents a fan motor upon the hollow shaft 30 so
as to assist in imparting rotary movement to said shaft, and 12" are sweeps carried
by said shaft for keeping the inner faces of the cylinder head clear. 22, 22", are
shields which are carried by hollow shaft 30 so as to be held in position over the
agitators 13 and to receive the dust dislodged by said agitators and deliver the
same into the hollow shaft 30 from whence it escapes through a spout 31.
reason of the nature gearing 17, 18, and of the action of the air upon the fau
motor 4, a slow rotary motion is imparted to said shaft 30 together with all the parts
carried by it, said motion being governed by the feeding action of the agitator 13
as hereinbefore explained. The result is that while the walls 9 and 10 together
with the inclosed material 11 remains stationary, the agitators 13 will gradually
pass around through said material and treat all parts of it successively and a little
at a time while leaving the remainder in condition to arrest the dust, from the air
which is passing through the walls. 32, 32, are stand-pipes through which
material is introduced and which may be kept filled to take the place of wear
and keep the material under proper pressure and packed condition in the
machine."
By
On
In Figs. 4, 5 and 6, is shown a form of machine adapted to be mounted over an
ordinary cyclone dust-catcher. The dust catcher is represented by 33 and its
axial opening at 34. 35 represents a conical chamber formed of double perforated
walls 9, 10, having the space between them filled with the filtering
material 11. 36 represents a shaft which carries a fan motor 4 in the
settling chamber 33 and an angularly arranged sweep 37 in the chamber 35.
its upper end, the shaft carries a gear wheel 38 and a drive pulley 39. 40 is a
casting which fits in a socket 41 so as to be adapted to turn in the upper end of the
chamber 35, and this casting carries the agitator 13 locate! between the walls of
the chamber and the shield 22 which hangs down over the outer wall of the
chamber in position corresponding to the agitator 13. By the nature of the
connection between the agitator 13 and the shaft 36, and the feeding action of said
agitator, the casting 40, together with the parts carried by it, slowly travel around
the cone-shaped chamber 35. +2 represents a trip valve which normally closes

page_text: the lower end of the shield 22 so as to prevent the escape of the dust, but
which is engaged and opened by a projection 43, each time the shield 22 comes
opposite a fixed spout 44. 45 is a spout leading from the floor of the conical
chamber and serving to deliver into the spout 44, the material which settles in
chamber 35.
In Figs. 7 and 8 is shown an upper centrifugal sifting chamber 50, having a
tangential inlet 51 for dust-laden air and a spouted outlet 52 for escape of heavier
particles which are separated by centrifugal force, and beneath the eye of the
settling chamber, is chamber 53 having a rotatable drum 54 with a single perforate
bottom 55 upon which rests a body of filtering material 11. The air escaping
from chamber 50, passes downward through filtering material 11 and all remaining
dust is arrested. 56 is an agitator comprising a rake pivoted by its back at 57,
and receiving a rocking motion from an arm 58 engaged by crank 59 of shaft 60,
which is rotated by pulley 61. The rocking movement thus imparted to the rake,
agitates the filtering material sufficiently to permit the escape of arrested dust
from the restricted area of agitation while the major part of the material remains
in condition to arrest the dust from the escaping air, and the arrested dust which
is dislodged by agitator 56, is collected in shield 22 and discharged through
spout 62, by the worm 63 on.shaft 60. A pawl 64 on the agitator 56, engages a
peripheral ratchet 65 on the drum 54 and each time the agitator vibrates, advances
the drum by the space of one tooth. By this means the entire body of filtering
material is brought under the cleansing action of the agitator from time to time
while the operation of arresting the dust goes on uninterrupted. 66 is the turning
post of the drum stepped in the bearing 67, and carrying at its upper end a swivel
bearing 68 for the agitator. 69 is a packing closing the crack between drum 54
and the wall of chamber 53.
My invention as above explained, involves the continuous use of the same body
of granular material, which is passed in a continuous circuit through the machine,
collecting the dust from the dust-laden air discharging the purified air, then
discharging the dust and then carrying back for re-use, the granulated material
from which the dust has been sifted out. The same body of wheat or other
granular material may thus be used over and over for many mouths, and for an
indefinite period, and when it is desirable to replace or to renew it, the used wheat
or other granular material may be drawn out by means of a slide 33, Figure 4,
Sheet 5 and a new supply may be introduced at top, through a spout or hopper 34.
The embodiment of the apparatus illustrated in Figs. 1 and 2, Sheet 4 is superior
in that the wheat, if wheat be used as the granular material, is subjected to no
material wear or destructive abrasion, so that the same body or material may be
used almost indefinitely without material loss. The form of apparatus illustrated
in Figs. 3 and 4 subjects the wheat to greater wear and this may, if desired, bu
utilized as a wheat scouring apparatus, while carrying into effect my improved
process for collecting dust, by forcing the dust-laden air, by the action of a blast
through a body of granular material which is moving continuously in an endless
circuit, suitable means being provided to draw off the wheat when sufficiently
scoured aud in condition for grinding, and to introduce a new supply.
By "granular material "as is used in the specification and claims, I do not limit
myself to grain of any particular kind, or to any material of substantially similar
shape, but desire to cover by such term, any material made up of small particles
which if delivered in mass into the space which defines the filtering wall, will form
small spaces or pockets through which the air may pass and in which the dust or
substance carried by the air, will lodge or otherwise be arrested by coming in
contact with the surfaces of the particles which go to make up the intercepting
wall. It is found in practice to be of utmost importance to provide for a repeated
use of the same body of granular material for arresting the dust, for without this
feature, the device would be impracticable, owing to the requirement of fresh
material in unobtainable quantities, and owing to the fact that such fresh material
is always impregnated with dirt aud foul substances which would become mingled.

page_text: with the arrested dust and thus render useless the product obtained by the dust
catcher for anything more valuable than feed. In all profitable mills where close
yield is obtained, the dust from the purifiers, which it is intended to collect by my
present apparatus, is bolted, and the flour and middlings separated and made into a
second grade flour which is worth much more than feed. Hence it is of greatest
importance that the material arrested by the dust catcher, should be kept free from
the foul matter which is always present in fresh granular material. By the
continual or repeated use of the same wheat or granular material, the latter
becomes at once freed from foul substances, and hence there can be no deterioration
of valuable products which are arrested by passing the dust-laden air through the
continuously returning mass, of such material. The idea of continually returning
the granular material to the filtering wall is therefore of vital importance. By
suitably advancing the granular material, the component parts of the filtering
medium are continually sifted so that new and unobstructed pockets are continually
being formed and the filled pockets continually pass off to be emptied of the
arrested dust. By delivering the dust-laden air into the chamber by means of an
air blast, the heavier particles are precipitated by the force of the blast and pass
to the separating device below without coming into contact with the filtering wall,
thus materially increasing the capacity of the machine, the filtering capacity being
limited by the quantity of material which will be received by the pockets which
form in the granular material.
A further very important result obtained from the continuous use of the same
material with the intervening mechanism which continuously removes the arrested
matter therefrom, is that a machine is produced which is. a complete automatic
entity in itself and is not dependent in the performance of its functions upon
association with other mechanism, for the supply of some material feature to its
operation.
My invention is of great utility for purifying the air in mills and other
establishments. By the use of fans, taking the dust-laden air at one or more
points, passing it through my apparatus and discharging the purified air therefrom,
at another distant point or points, the entire atmosphere of a mill may be relieved
of dust, which is a constant source of danger, in causing explosions, and is also
highly prejudicial to health.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The process herein described of collecting dust, which consists in passing the
dust-laden air through a suitably arranged body of granular material, separating
the dust taken up by said material and returning the latter continuously for re-use,
as explained.
2. The process herein described, of collecting dust which consists in forcing
the dust-laden air, under pressure through a body of granular material, moving
continuously between suitable screens, sifting the dust out of the granular material,
and returning the latter continuously for re-use.
3. The combination of a chamber having a wall comprising a suitably arranged
body of granular material which has an unobstructed communication on its outer
side with the atmosphere, means for shifting the component particles of such
granular material and a blast apparatus receiving at its inlet the dust-laden air
and delivering it into said chamber, and constructed to maintain pressure therein,
substantially in the manner and for the purpose set forth.
4. The combination of a chamber having a wall comprising a suitably advancing
body of granular material, a blast apparatus receiving the dust-laden air and
delivering the same into said chamber, means for removing the dust from the
granular material and means for continually returning the purified granular material
to the continuously moving body forming the wall, as explained.
5. The combination of a suitably advancing body of granular material, means

page_text: for forcing dust-laden air therethrough means for sifting the dust out of the
granular material for the purpose of purifying said material and means for
repeatedly elevating and returning the purified granular material for re-use,
substantially as explained.
6. The combination with descending columns of granular screening material of a
fan for collecting dust-laden air, a separating mechanism for removing the dust
from the screening material for the purpose of purifying said material and an
elevating device for returning the purified material whereby a continuous
circuit of dust arresting granular material is produced, and the dust separated
therefrom.
7. A dust collector comprising a wall of air-filtering material through which the
air is forced, and agitating mechanism in said wall, for agitating the component
parts of the material and permitting the escape of the dust therefrom, as
explained.
8. A dust catcher comprising a filtering body through which the dust-laden air
is forced and by which the dust in said air is arrested, an agitator, agitating the
component parts of the filtering body surrounding it, to permit the escape of the
dust arrested thereby, and means for producing. a relative movement between
the agitator and the body of filtering material whereby all parts of the latter are
successively relieved of their dust, as explained.
9. A dust catcher comprising a wall of air-filtering material, an agitator operating
upon a restricted portion of the filtering material to produce relative movement
between the component parts and release the arrested material therefrom and
permit its discharge by the current of air, a conducting passage corresponding in
position to the agitator and receiving and conducting away the dust released by the
latter, and means for effecting a relative movement between the body of material
and the agitator and conducting passage whereby all parts of said material are
successively treated, as explained.
10. A dust catcher comprising a settling chamber, means for delivering a
current of dust-laden air into said settling chamber in a manner to produce a
vertical movement and cause the settling of the larger particles suspended in the
air, and a filtering wall through which the air bearing the finer particles is
subsequently forced and by which said finer particles are removed from the air, as
explained.
11. In a dust catcher, the combination of a circular chamber. having double
perforated walls, a body of filtering material located between said walls, an agitator
comprising a shaft having projections which tend to feed the material relatively to
the shaft when the latter is rotated and means substantially as described for
rotating said shaft as explained.
12. In a dust catcher, the combination of a circular chamber formed of double
perforate walls and having a space between them filled with a filtering medium
made up of small component parts, a shaft mounted concentrically in said chamber
and a shaft projecting radially from said concentric shaft, projecting into the body
of filtering material, having projections which agitate said material, and adapted
to be moved progressively through said material, by the concentric shaft, as
explained.
13. In a dust. collector the combination of a chamber formed of double walls
perforated for the escape of air from the chamber and having a space between
them filled with a filtering medium made up of small parts, a shaft mounted to
rotate concentrically in the chamber, an agitator geared to the concentric shaft and
projecting radially from the same, in the body of filtering material between the
walls, and provided with projections which cause progressive movement of the shaft
through the material when rotated as explained.
14. In a dust collector the combination of a chamber formed with double walls
perforated for the passage of air through them and having a space between them
filled with a filtering medium of small component parts, a central shaft in the
chamber, an agitating shaft receiving movement from the central shaft and

page_text: projecting from the latter into the body of the filtering material and a brush
moving over the face of the inner wall of the chamber to clear the same and
receiving motion from said central shaft, as explained.
15. In a dust collector the combination of a hood formed with double perforated
walls, and supplied between said walls walls with a layer of granular or fibrous.
material said hood being adapted to be placed over the air outlet of an ordinary
centrifugal dust collector, whereby the fine particles of dust are arrested, as
explained.
16. In a dust collector the combination of an air receptacle, having a closed top
and perforated bottom and a layer of granular or fibrous material in connection-
with a dust discharge spout, while the major part remains at rest for intercepting
the dust as the air escapes.
Dated this 13th day of April 1897.
BOTTOMLEY & LIDDLE,
154 St. Vincent Street, Glasgow, Applicant's Agents..