Year: 1887

page_text: I, HENRY SIMON of No. 20 Mount Street, Manchester, in the County of Lancaster,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to travelling filters such as are used in milling and other
operations to clear the air from dust. Such a filter consists of an endless travelling
web of porous fabric through which the air is drawn by an exhaust fan, it being
intended that only the pure air shall pass through its pores, while the dust is deposited
externally.
In employing such filters, great difficulty is experienced in preventing leakage of
the dust laden air past the edges of the travelling web, and several expedients have
been tried to prevent this, such as binding the edges of the web with bands or cords
and causing these to travel along guides more or less closely fitting them. Now,
according to my invention, I extend the web in width sufficiently for its edges to pass
through slots at each side of the casing of the filter, and I bind these edges with
leather or other flexible material, which binding covers the slots externally and in
great measure prevents inward leakage of air; but, should air leak past the binding
and through the slots into the interior of the filter, the air thus leaking in, being
taken from outside, is not dusi laden, as when leakage takes place from the interior of
the machine, and consequently the air passing from the filter to the fan remains
purified from dust, notwithstanding such leakage as may take place at the edges of
the filter.
200
1
L
1007

page_text: I, HENRY SIMON, of 20 Mount Street, Manchester, in the County of Lancaster,
Engineer 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 :-
My invention relates to travelling filters such as are used in milling and other
operations to clear the air from dust. Such a filter consists of an endless travelling
web of porous fabric through which the air is drawn by an exhaust fan, it being
intended that only the pure air shall pass through its pores while the dust is deposited
externally.
In employing such filters, great difficulty is experienced in preventing leakage of
the dust-laden air past the edges of the travelling web, and several expedients have
been tried to prevent this, such as binding the edges of the web with bands or cords
which are either caused to travel along in tightly fitting grooves fixed on the inner
sides of the filter casing, or to travel in open slots formed in the sides of the casing
in which they are made to fit tightly by means of packing in order to prevent
passage of air.
In the first mentioned arrangement however the dust has leaked through the
grooves from the one side of the filter web to the other, notwithstanding the tightness
of the packing, and dust laden air has consequently been blown by the fan into the
mill, and in both cases, the tight fit of the packing or binding renders it liable to stick
or jam in the grooves or slots thereby greatly impeding the motion of the filter.
Now, according to my invention I entirely obviate these difficulties by causing the
edges of the travelling filter web to pass freely through open slots in the casing,
avoiding the use of all packing, the outer air being to a certain extent free to enter
the filter through such slots in consequence of the suction exercised within the filter,
which suction will also cause the filter web to be pressed against the one side of
the slot so as more or less to prevent ingress of air on the suction side, while such
air as does leak in from without is of no detriment whatever, as it is only pure air
that passes in and consequently cannot in any way create dust or interfere with the
working of the machine. On the other hand, no dust laden air can pass out through
the open side of the slot because the indraught of air from the outside prevents this.
In order to prevent excessive ingress of air, the edges of the filter_web_are_by.
preference extended sufficiently beyond the outside of the casing to have a binding
or band of leather or other material attached to them which binding or band in
covering the slot will more or less restrict the ingress of air.
The accompanying drawing shews a part section of a filtering apparatus with the
travelling filter webs arranged according to my above described invention.
A A are the travelling filter webs, shewn in cross section, through which the dust
laden air passes in the direction of the arrows at CC to the outlets D D in the
casing E through which it is propelled by the fan, so that the dust is separated from
the air and retained on the outer surfaces of the filter webs. The edges of the latter
pass freely through slots E' in the casing E and have bands B of leather or other

page_text: material attached to them on the outside of the casing. These bands cover the
slots in the casing, and being pressed against the casing by the pressure of the
atinosphere, greatly restrict the inward leakage of air, while such air as does leak
in in the direction of the arrows F will assist in pressing the web against the edge
of the slot owing to the exhaust between the filters A A, so that the outer air
practically will only enter on the outer sides of the filters. Should notwithstanding
the contact of the filter web with the edge of the casing some of the outer air still
pass into the middle space, this air not being dust laden will not have any detri-
mental effect on the action of the filter.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. In dust filters the use of a travelling filter web whose edges pass freely through
slots in the casing through which slots the outer air is free to enter into the interior
of the casing, substantially as herein described.
2. In dust filters the use of a travelling filter web whose edges pass freely through
slots in the casing beyond which they have bands or cords attached to them so as to
cover the slots and restrict the ingress of air whilst the webs are pressed by excess of
atmospheric pressure against the edges of the slots on the exhaust side, substantially
as, herein described.
3. In dust filters the use of a travelling filter web passing through slots in the
casing and having bands or cords attached to them outside the casing, which bands
are pressed against the slots by atmospheric pressure, and thus restrict the entrance
of air, substantially as herein described.
Dated this 30th day of June 1888.