IMPROVEMENTS IN APPARATUS FOR FILTERING OR PURIFYING AIR ESCAPING FROM MILL-STONES AND OTHER DUST PRODUCING APPARATUS
Year: 1882

page_text: LETTERS PATENT to Emile Fiechter of Liverpool in the County of Lancaster
for an invention of "IMPROVEMENTS IN APPARATUS FOR FILTERING OR
PURIFYING AIR ESCAPING FROM MILL-STONES AND OTHER DUST PRODUCING
APPARATUS" A communication from abroad by G. Baier of Ulm a/D in the
kingdom of Wurtemberg.
PROVISIONAL SPECIFICATION left by the said Emile Fiechter at the Office
of the Commissioners of Patents on the 6th April 1882.
EMILE FIECHTER of Liverpool in the county of Lancaster
"IMPROVEMENTS
IN APPARATUS FOR FILTERING OR PURIFYING AIR ESCAPING FROM MILL-STONES AND
OTHER DUST PRODUCING APPARATUS."-A communication from abroad by G. Baier
of Ulm a/D in the kingdom of Wurtemberg
This invention consists essentially, first, in a double cylindrical or preferably
slightly inverted conical shaped filter caused to be violently shaken at intervals
when the air is not passing, second in apparatus for intermittently shaking same.
Above the stone I place a strong iron chamber, and in this chamber suspend a
double cylindrical or conical filter of flannel or other filtering material, with
metallic top and bottom, the former fastened to the outer chamber the latter
suspended. Between the two filtering cloths I may place valves in the bottom to
extract the dust by at intervals. In the centre of the filter is a wire basket to
keep it distended. On the vertical shaft passing into or through the filter chamber
a disc is keyed which carries the bottom of the filter This shaft is preferably
provided with a spring to cause it to recover its normal position when drawn up
in the process of shaking the filter. An Eccentric working at quick speed rapidly
agitates this rod up and down for a single minute at intervals of say fifty minutes
apart. During this time by automatic appliance the valve in the pipe leading.
from the filter to the exhauster is closed and another opened, thus allowing during
the shaking free communication between the interior of the filter and the outer air

page_text: while cutting off the exhauster and consequent suction. This is necessary to enable
the fluff sticking to the outer surface of the filter cloth to fall off.
There are various modes of giving the intermittent motion to the eccentric-one
is by differential gear throwing the eccentric out of gear as a catch on the
differential gear passes a given point a spring putting it into gear the moment the
catch has passed; but the plan the original designer prefers is by having a counter-
shaft and throwing the belt onto a loose pulley at intervals. The mode of throwing
this into gear at intervals is as follows. By worm and wheel gearing from the
driving shaft a cam is caused to make one revolution say every half minute,
another cam geared to this revolves say once every five minutes, and for an angle
of 36 degrees or so this circular cam is cutt away. The other circular cam is also
cut away for a part of its circumference. These two cut away portions will
coincide once every fifty minutes and the two friction rollered tappets on the belt
guide will fall into them thus allowing a spring to bring the belt guide back so as
to throw the belt onto the last pulley for about a minute. During that period
only the shaking action will be in gear. A semaphore arm on the valve gear of
the filter press is at the same time worked by a cam on the belt guide and thus the
valves are operated as before stated simultaneously with the throwing into and out
of action of the shaking apparatus.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent and of
an Order of the Lord Chancellor filed by the said Emile Fiechter in the Great
Seal Patent Office on the 20th October 1882.
EMILE FIECHTER, of Liverpool in the County of Lancaster,
"IMPROVEMENTS IN
APPARATUS FOR FILTERING OR PURIFYING AIR ESCAPING FROM MILL STONES AND
OTHER DUST PRODUCING APPARATUS."-A communication from abroad by G. Baier
of Ulm a/D, in the kingdom of Wurtemberg.
The object of this invention is to provide a stive proof and automatic exhaust
system for filtering the air and collecting what stive may escape from mill stones
in grinding or flour mills. It consists, essentially 1st in a double cylindrical or
preferably slightly inverted conical shaped filter caused to be violently shaken at
intervals during a period while the pressure of the air on the inside is removed,
2nd in apparatus for intermittently shaking same.
In the drawings are shewn a front and sectional elevation of the apparatus, In
these A. is a door opening into the case B of the filter which is strongly made and
preferably of iron. C casing surmounting or enclosing a set of stones. D is the
wire case or basket which holds the cloth filter or screen in position and is affixed
to the vertical shaft E. E. spiral spring on shaft E. F inner cloth of screen or
filter. G outer cloth of same. H pipe for the passage of purified air. I valve in air
passage H. I¹ lever which actuates the valve I. J slide or cover for air inlet J'.
K lever which actuates the valve I. L a slide attached to the lever or rod Y,
which slide moves the lever K. M weight on lever I¹ N belt connecting the
eccentric N'. with pulley N connected to shaft E. O fast and P loose pulleys
for actuating eccentric N¹. R. driving pulley, S worm, gearing into worm wheel T.
U spur wheel driven by pinion on the shaft of the wheel T. V. and W cams
which operate the strap fork lever Y. X. spiral spring on lever Y. Z studs on
lever which work in the recesses in the cams V. and W.
The strong iron casing B is placed above the mill stones, and in the chamber
formed by the casing B, is suspended a double cylindrical or conical filter G, F, of
flannel or other suitable filtering material with metallic top G₁ fastened to the sides
of casing B and metallic bottom F¹ suspended by means of the cage D. on shaft E.
Valves may be placed at g. f. in the bottom between the two filtering cloths
through which to remove any stive that may collect between the cloths.
The air laden with fine particles of flour passes from the stones in the direction
shown by the arrows and coming in contact with the woollen cloths or other
filtering medium the air passes through to the passage H while all particles of
stive or dust remain adhering to the filtering cloths. A layer of flour is thus
gradually formed on the sides of the filter which would at last completely obstruct
the passage of the air were it not cleared off at certain intervals of time. As this
clearing cannot be so conveniently performed during the passage of the air as
when the latter is arrested and the pressure removed, a valve arrangement is pro-
vided which opens when the passage through the pipe H is closed and admits fresh
air to the interior of the filter thus reducing the pressure on its sides. On the end.
of the lever attached to the valve I is fixed an external slide J which when the
valve I is open completely closes the inlet J¹ but when the valve is closed it falls
into the position shown in the drawing leaving the inlet open allowing free access
of air to the interior of the filter.
The valve I is opened and closed by the action of the lever K. and weight M
and the intermittent motion is arranged in such manner that the closing of the
valve I and passage H, with the inlet of air through the passage J¹ takes place:

page_text: :
three seconds before the movement of the filter and the passage H is again opened
and the air inlet closed in 20 seconds after the movement or agitation of the filter.
"This movement or agitation of the filter is caused by the eccentric N¹ which by
means of a strap N conveys its motion through the pulley N and shaft E to the
cage D.
As the eccentric revolves the cage rises and falls and shakes the cloth
causing the stive or particles of dust adhering to it to fall off. Motion is conveyed
to the eccentric N¹ from the pulley O through the bevel gearing n.
O. and P are
fast and loose pulleys on a shaft in hanging bearings and the driving strap is
moved from one to the other by the same lever that operates the lever K for
opening and closing the valves in the pipe H thus providing that the opening
and the closing of the valves and the agitation of the filter shall always be in
consonance. When the driving belt is shifted from the loose pulley P to the fast
or driving pulley O the several parts of the apparatus are in the relative positions
as shown in the drawings. By the movement of the slide L the lever I' is turned
opening the inlet J¹ and closing the valve I in the interior of the tube while at
the same time the axis of the eccentric is caused to rotate and the filter in case B
subjected to a shaking motion in a vertical direction.
.
The shifting of the belt, the opening and closing of the valves and the agitation
of the filter take place after regular intervals of say 15 minutes duration and the
shaking continues while the strap is on the pulley O for a period of say one
minute at each operation.
The driving pulley R receives motion from a belt and conveys it through the
worm or screw S to the wheel T which moves on one tooth at each revolution of
the worm S. A pinion t on the axis of the wheel T carries the motion to U. the
proportion between the pinion t and the wheel U. being such that the wheel T will
make ten revolutions for every one made by the wheel U.
'
The drums or cams V and W provided with recesses as shewn are keyed to the
shafts of the wheels T and U. and revolve in a similar manner. When the cam V
describes its tenth revolution the cam W will have described one revolution and at
this point the recesses on the cams coincide.
The friction rollers Z on the rod or lever Y then fall into the recesses in the
cams and the rod acted upon by the spring pushes the belt to the extent of
about 3 inches from one pulley to the other and at the same time cuts off the
internal air current in the tube H. by the connection K and L. with the valve I,
opens the air inlet J¹ turns the eccentric drum and shakes the stive filter. After
one minute or as soon as the friction roller Z on the rod Y is acted on by the
cam V the throttle valve I is opened automatically by the action of the weight M,
the air inlet J is closed, the belt is shifted to the loose pulley and the apparatus
remains stationary for another 15 minutes.
The object of most of the systems of automatic suction apparatus for flour mills
heretofore constructed is to close the valve in the air pipe at certain intervals and
knock the filter or stive collector.
Observations made for a series of years by Mr. G. Baier in his own and other
works lead him to the conclusion that the accomplishments of this object must
always give an unsatisfactory result and it has been ascertained by continual
experiments that a thorough and effectual clearing of the filter can only be per-
formed when the pressure of air within it is removed, and the object of this
invention is to avoid these disadvantages and to produce a permanently effectual
stive proof and regular suction or exhaust apparatus for flour mills the
distinguishing features of which are as follows namely:
1st That by reason of its double filtration the air is completely freed from stive.
2nd That the disengaging and throwing into gear for cleansing of the filter is
effected by simply shifting a belt so that a single disengaging device is sufficient
for all the exhaust apparatus in a mill.
3rd That the motion for cleaning the filter is not obtained by a knocking action
but by the displacement or shaking action of an eccentric whereby the desired
result is more effectually obtained:

page_text: 4th That during the clearing of the filter the air pipe valve is not only closed
but is so arranged that at the proper time fresh air is admitted to the inner space
in the filter and by thus reducing the pressure on the inside caused by suction
the stive accumulated on the filter is enabled to be removed with facility and
thoroughness.
Having now described this invention as communicated to me I wish it to be
understood that what I desire to protect under the hereinbefore in part recited
Letters Patent is :-
The apparatus for filtering or purifying air escaping from mill stones and other
dust producing apparatus substantially as herein described and shown; and
especially (1) the double filter (2) the mechanism for changing the current of air
and simultaneously shaking the filter, not with a knocking but a shaking action
and (3) the system of cleaning single dust filtering apparatus which consists in
momentarily diverting the current of dusty air which is ordinarily drawn by an
exhaust through the apparatus and simultaneously admitting the outer air into
the partial vacuum formed while at the same time the filter is drawn up and
down and thoroughly shaken by mechanism put into action simultaneously with
the change of current..
In witness whereof I, the said Emile, Fiechter have hereunto set my hand
and seal, this nineteenth day of October in the year of our Lord one
thousand eight hundred and eighty two.
EMILE FIECHTER (L.S.)