Improvements in or Appertaining to Dust Collecting and Apparatus .therefor
Year: 1889

page_text: Date of Application, 5th Mar., 1889
Complete Specification Left, 14th Dec., 1889-Accepted, 5th Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in or Appertaining to Dust Collecting and Apparatus
.therefor.
A communication from abroad by HERMANN KRÄMER, of Schorndorf, Wurtemberg,
in the Empire of Germany.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn, in the County of Middlesex, Civil
Engineer, do hereby declare the nature of this invention to be as follows:-
The ventilator which forms the object of this invention is distinguished from other
ventilators in that it separates from the wind that is being forced through it, the
particles of dust contained in the same, while avoiding the necessity for complicated
and costly dust collecting apparatus in flour mills and other establishments in which
much dust is produced. This apparatus works after the manner of a centrifugal
separator, and thoroughly purifies the air of particles of dust. This ventilator consists
essentially of an air supply channel to the outlet of which a funnel-shaped shell or
case is attached.
Within this shell rotate a fan or fans fastened on to a shaft driven by means of belt
pulleys or their equivalent. These fans draw up the air impregnated with dust and
carry it round in a rotary direction. Since air and dust are of different specific
gravities, the particles of dust, being of the greater specific gravity, are separated
from the lighter particles of air in consequence of centrifugal force. The dust
collects on the inner wall of the shell of the ventilator, and then passes through
openings into depositing chambers, while the purified air is carried on its course
through a channel.
The ventilator consists of a fixed and preferably cylindrical channel, through which
the air enters, said channel ending in a funnel-shaped mouth or opening. A solid
shell or case surrounds the opening of the said channel.
In the funnel-shaped prolongation of the channel is placed the fan, firmly fixed on
a revolving shaft; a drum, preferably made of wire gauze or perforated timplate is
also fixed on to this said shaft, so that the fan and the drum are revolved with the
shaft by means of a belt pulley. A cylinder is fastened to the open end of the shell
or case, by means of an annular connecting wall or partition, but at such a distance
from the outer wall of the air supply channel thata sufficient space will be left. between
these two parts to allow the escape of the air supplied to the shell or case. The above-
mentioned drum is also connected with a second internal drum, also made of wire
gauze or perforated tinplate, by means of an annular wall corresponding with the wall
which connects the cylinder with the case or shell. This wall projects in the form
of a flange beyond the outer drum; a flange is also placed on the other end.
On the lower part of the case or shell are three slits. One of these runs right
across the case, while the two others, though wider than the former, are only about
a quarter of the length of the same. A box is fastened underneath the case and is
divided into three compartments, corresponding with the three slits, by means of
closely fitting partitions, so that each slit opens into one of the said compartments.
In consequence of the rotation of the shaft with the fans, air is drawn in through the
supply channel and is carried round in rotation with the fans. Now since, as above
mentioned, dust and air are of different specific gravities, the dust will be separated
from the air as in a centrifugal machine, this process being assisted by the perforated
drum which revolves with the fan. The dust therefore, collects on the inner wall of
the case or shell and passes through the slits into the different compartmentsaccording

page_text: as its particles are coarse or fine and therefore heavier or lighter, and there settles
and accumulates in heaps.
The air purified and freed from dust then leaves the apparatus through the passage
formed between the cylinder and the supply channel.
According to a modification of the apparatus described above, the apparatus consists
of a cylindrical supply channel on the front of which a funnel-shaped case or shell is
placed in which the fans rotate. A perforated tinplate drum is also fixed on this
shaft so that it will rotate with the latter.
A cylindrical inner shell is fixed inside the outer shell at a given distance from
the drum, forming, with suitable radial partitions and the outer shell, a series of
channels, lying side by side, and running round the periphery of the shell hermetically
shut off from the outside and from each other.
These channels are connected with the dust separating chambers through slits in
the 'inner shell and parallel with the circumference, and from thence with the
depositing chamber through slits across the circumference. It is thus possible to
separate out the dust without it being necessary to produce any centripetal motion
in the air, for the continuous axial motion of the same against the inner shell with
the lateral slits round its periphery, is sufficient for the purpose.
The channels running round the shell may be considered as coming between the
drum and the dust depositing chambers.
The dust is carried off in the following manner :--
A draught is created in the channels running round the drum by the rotation of
the fans driven by the belt pulley, which wind taken in cross section has the same
direction of motion, and is concentric with the rotation of the fans, but in longitudinal
section revolves round the centre of a cross section of the channel.
These currents carry off the dust through the longitudinal slits to the depositing
chambers.
These depositing chambers which are also hermetically shut off from each other,
are closed at the bottom either by closely fitting and constantly rotating roller, or by
an airtight lid. In the first case the dust is deposited in grooves in the roller and is
constantly carried away by the rotation of the cylinder, while in the latter case, the
dust that has collected must be emptied out from time to time when the machine is
not working.
Further, instead of the fans, a screw wheel might be placed on the shaft which will
then impart to the wind as it enters through the supply channel a screw-like motion.
The separation of the dust is in this instance carried out as in the apparatus with
rotating fans, but the effect is in this case much reduced.
The number of circumferential channels may of course be increased or diminished
as desired.
Total
14.11nt Wu 1980
WM. P. THOMPSON & Co..
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or Appertaining to Dust Collecting and Apparatus
therefor..
A communication from abroad by HERMANN KRAMER, of Schorndorf, Wurtemberg,
in the Empire of Germany.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.L.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn in the County of Middlesex, Civi!
Engineer, do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly describedand ascertained in and by the following
statement:-
The ventilator which forms the object of this invention is distinguished from other

page_text: ventilators in that it separates, from the air that is being forced through it, the
particles of dust contained in the same, while avoiding the necessity for complicated
and costly dust collecting apparatus in flour mills and other establishments in which
much dust is produced.
This apparatus works after the manner of a centrifugal separator and thoroughly
purifies the air from particles of dust.
This ventilator consists essentially of an air supply channel, to the outlet of
which a funnel shaped shell or case is attached. Within this shell, rotate a fan or
fans, fastened on to a shaft driven by means of belt pulleys or their equivalent.
These fans draw up the air impregnated with dust and carry it round in a rotary
direction. Since air and dust are of different specific gravities, the particles of dust,
being of the greater specific gravity, are separated from the lighter particles of air
in consequence of centrifugal force. The dust collects on the inner wall of the shell
of the ventilator, and then passes through openings into depositing chambers, while
the purified air is carried on its course through a channel.
The ventilator, shown in the drawing, Figures 1, 2 and 3, in longitudinal, lateral
and horizontal sections respectively, consists of a fixed, and preferably cylindrical
channel B, through which the air enters, said channel ending in a funnel shaped
mouth or opening. A solid shell or case A surrounds the opening of the said
channel B.
In the funnel shaped prolongation of the channel B is placed the fan F firmly
fixed on a revolving shaft ; a drum C, preferably made of coarse wire gauze or
perforated sheet metal, is also fixed on to this said shaft, so that both the fan F and
the drum Care revolved with the shaft by means of the belt pulley G. A
cylinder A is fastened to the open end of the shell or case A by means of an annular
connecting wall or partition U, but at such a distance from the outer wall of the
air supply channel B that a sufficient space will be left between these two parts to
allow the escape of the air supplied to the shell or case. A. The above mentioned
drum C is also connected with a second internal drum E, also made of wire gauze or
perforated sheet metal, (of a finer mesh than cylinder C) by means of an annular
wall 1 corresponding to the wall which connects the cylinder A' with the case or
shell A. This wall projects in the form of a flange beyond the outer drum C, as
shown in Figure 1: a flange is also placed on the other end of E. E' E' are
discharge orifices, opening from the space between A and E into a suitable settling
chamber having a discharge shute ³.
T
On the lower part of the case or shell A are three slits 0 01 02 (Figures 2 and 3).
One of these, 02, runs right across the case, while the two others, and 0', though
wider than the slit 02, are only about a quarter of the length of the same. Similar
slits can be made in any number required at the sides and top of the case. A box is
fastened underneath the case A, and is divided, by means of partitions, into thres
hermetically closed compartments RRR, corresponding to the number of the slits,
so that each slit opens into one of the said compartments. In case more slits are
required, each is fitted with a corresponding hermetically closed casing. In con-
sequence of the rotation of the shaft with the fans F, air is drawn in through.
the supply channel in the direction of the arrows, and is carried round in rotation
with the fans. Now, since, as above mentioned, dust and air are of different specific
gravities, the dust will be separated from the air as in a centrifugal machine, this
process being assisted by the perforated drum C, which revolves with the fan.
In a machine constructed as above described, it has been found in actual practice
that the dust which collects on the inner wall of the case or shell A passes through
the slits 0 01 02 into the different compartments RR according as its particles
are coarse or fine, and therefore heavier or lighter. In these compartments the dust
settles or accumulates in heaps. The cause of this separating action is not quite
apparent, but the following seems to be a probable explanation of it:-
The dust laden air enters the right end of the casing A between the funnel shaped
prolongation of the trunk B and the end wall of the casing. The rotative force of the
fan F tends to cause the air to move axially, that is, in a circular path round the inner

page_text: periphery of the casing and parallel to the end wall thereof as shown by the arrow E,
Figure 3. There is also, however, a force or forces tending to cause the air to travel
along the casing towards the left end thereof in the direction of the arrow H',
Figure 3. This is, no doubt, due to the fact that the exit for air from the chamber A
is some distance to the left of its entrance thereto, and also to the fact that the
radial movement of the air (due to centrifugal force) being arrested by the wall
of the casing, the air tends to move along the casing in the form of eddies, as
indicated by the dotted arrow at the top of Figure 1. The resultant of these
'forces lies somewhere along the lines indicated by the arrows h, h, h, Figure 3.
The heaviest and largest particles, having a greater centrifugal force than the
smallest and lightest particles, are carried round the casing with a greater velocity
than the lighter particles, so that they travel in the direction of the arrows and
fall into the slit before they have time to move far enough to the left to reach the
slit 01. In a similar manner, it will be readily understood that the medium particles
follow the path of the arrows and fall into the slit O', while the smallest and
lightest particles travel, as indicated by the arrows h²² and fall into the slit 0.
It is also found in actual practice that some of the finest dust also passes through
the sieves C and E into the space between the latter and the casing and thence
through the openings E' E' into the settling chamber E. This action may possibly
be accounted for as follows:-
A portion of the air, moving in the form of the lateral eddies or vortices indicated
by the aforesaid arrow H2, passes in the form of similar eddies through the left end of
the sieve cylinders C and E into the space between E and A!, back through the right
end of the cylinder E, through the cylinder C into the space between it and A, and
back again through C to the outlet. This movement is represented by the dotted
arrow at the bottom of Figure 1. The finest portion of the dust which passes thus,
in the first instance through the sieve C, passes also through the sieve E into the
space between it and A. Here the eddying movement of the air, assisted by its
axial movement round the easing A', causes this fine dust to be discharged through
the openings E E' into the settling chamber E whence it may be removed by any
suitable means.
The air purified and freed from dust, then leaves the apparatus through the passage
formed between the cylinder A and the supply channel B.
A modification of the apparatus described above is shown in Figures 4 and 5 and
in longitudinal and cross sections. This apparatus consists of a cylindrical supply
channel E, on the front of which a funnel shaped case or shell C is placed, in which
the fans V, fixed on the shaft A, rotate. A perforated sheet metal drum S is also
fixed on this shaft so that it will rotate with the latter.
A cylindrical inner shell is fixed inside the outer shell M at a given distance
from the drum, forming, with suitable radial partitions R and the outer shell M, a
series of channels U³lying side by side and running round the periphery of
the shell hermetically shut off from the outside and from each other. These channels
are connected with the dust separating chamber T through slits S1 S2 S3 made in the
inner shell and parallel with the circumference, and from thence with the depositing
chambers L'LL through slits 01 02 03 across the circumference. It is thus
possible to separate out the dust without it being necessary to produce any centripetal
motion in the air, for the continuous axial motion of the same against the inner
shell M. with the lateral slits 23 round its periphery is sufficient for the purpose.
The ring.C of the same diameter is fastened for this purpose on the conical case C.
and the annular dust separating frame T is continuous for a space in order to keep
together the air passing through it. The channels UU Uj³ running round the
shell may be considered as coming between the drum and the dust depositing
chambers L'LL³. The dust is carried off in the following manner:--
A series of currents, similar to those described in reference to Figures 1 to 3, is
created in the channels running round the drum by the rotation of the fans V driven
by the belt pulley B. As seen in the cross section (Figure 5) these currents have an
axial motion around the channels. They have also, as seen by the arrows at the top

page_text: of Figure 4, an eddying motion round the channels, as taken in cross section. The
combined effects of these currents, taken in conjunction with the varying centrifugal
force of the particles, causes the heaviest particles to enter the channels U U², and
the lightest particles (which are the last to be influenced to the necessary extent by
the centrifugal force) io enter the channels 00
These currents carry off the dust through the longitudinal slits 010 to the dust
depositing chambers L'L².
These depositing chambers, which are also hermetically shut off from each other,
are closed at the bottom either by a closely fitting and constantly rotating roller W
or by an equally air-tight lid. In the first case the dust is deposited in grooves in
the roller and is constantly carried away by the rotation of the latter, while in the
latter case the dust that has collected must be emptied out from time to time when
the machine is not working.
Further, instead of the fans V, a turbine like screw wheel might be placed on the
shaft A together with the ring C and cover M, which will then impart to the wind, as
it enters through the supply channel E, a screw-like motion, so that all rotating parts
of the machine can be dispensed with, and it serves merely as a dust collecting
chamber. The separation of the dust is in this instance carried out as in the
apparatus with rotating fans, but the effect is in this case much reduced.
The number of circumferential channels may of course be increased or diminished
as desired.
Figures 6 to 12 represent various modifications of the main arrangement. Accord-
ing to Figures 6 and 7, the inner wall of the case can be made in the shape of a
diminishing or increasing cone from which the annular slits permit the dust to enter
the collecting boxes.
Figures 8, 9 and 10 represent two longitudinal and one cross section of a dust
collector with a vertical axle.
Figure 11 represents the arrangement of a four-cornered outer case, in which,
without specially prepared spaces, room is obtained for the collection of the dust.
Finally, Figure 12 represents a division of the outer case so that side spaces are
formed which are favourable to the collection of the dust.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I déclare that what I claim is:
1. A dust collecting ventilator, in which air laden with dust sucked through a
passage by means of rotating fans or similar working parts is caused to rotate and is
retained through this and similar apparatusor with the assistance of a rotating sifting
cylinder, and thereby, by means of centrifugal force, parts with the dust particles and
escapes by an inner passage, whilst the dust thrown out is collected in settling spaces,
substantially as described.
2. In a dust collecting ventilator such as described, the combination with an outer
casing of the fans For V, perforated drum C or S of considerably smaller diameter
than said casing and which traverses the dust separating chamber and is firmly fixed
on the fan axle, substantially as and for the purpose set forth.
3. In a dust collecting ventilator, the combination of a chamber serving as dust
separator which surrounds the ventilator cover with an air admission passage, situated
in the exit chamber in such a way that fresh air can always pass freely in and out,
substantially as described.
4. The dust deposit chambers RRR situated round the dust separation chamber
which are connected therewith by means of openings 001 and 02 and are hermetically
closed between one another and to the outside, substantially as and for the purposes
set forth.
5. The modified form of connection between the dust separating chamber and the
dust deposit chambers, consisting in the arrangement of slits in the annular
cover Maround which the circumferential passages UC, which are concentric with
the fan axle and are hermetically closed to the outside as well as between one another,

page_text: are placed, in such a manner that they communicate, by means of longitudina!
slits 00, with the dust deposit chambers L' L also hermetically closed to the
outside and each other, substantially as described and shown with reference to
Figures and 5.
Dated this 12th day of December 1889
WM. P. THOMPSON & Co.,
Agents for the Applicant.