Improvements in Bag Filters.
Year: 1889

page_text: Improvements in Bag Filters.
I, BENJAMIN JOSEPH BARNARD MILLS of 23 Southampton Buildings, in the
County of Middlesex, Patent Agent, do hereby declare the nature of this invention,
a communication to me from abroad by Jules Rétif, of Lyons, in the Republic of
France, Filter Manufacturer, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement,
reference being had to the accompanying drawings, and to the figures, and letters
marked thereon:-
The invention relates to that class of filter in which filtering bags are suspended
below a vat or reservoir containing the liquid to be filtered.
Hitherto these bags have been fixed below the vat or reservoir by means of ligatures
or screw threads, which, in apparatus containing a considerable number of these bags,
necessitates a long and delicate operation, and renders it very difficult to dismount
the bags from the middle.
With the present invention, the bags are introduced from above; and their joint
with the bottom of the vat or reservoir, is effected solely by the pressure of the
liquid.
Figure 1 of the accompanying drawing represents one method in which this result
is obtained.
The bag A, whose circumference may be much greater than the space it occupies
in the filter, is regularly folded or pleated, and placed in an openwork envelope B,
provided with a projecting flange b, around which it is turned. down and then fixed
by an exterior ligature d. The bag thus prepared, is passed downwards through the
conical opening in the bottom Cof the vat or reservoir, in such manner that the pad
or cushion formed by the bag being turned down around the flange b, makes a joint
with the conical part of the opening, in a similar manner to a valve on its seat,
the weight of the bag and the pressure of the liquid ensuring the tightness of the
joint.
Figures 2 to 5 show analogous arrangements with different forms.
In figure 2 the joint is made in a circular channel with the interposition of a
caoutchouc ring i. In figure 5 the openwork basket or envelope is replaced by a
simple socket or ring b; this form comprising only a bag, the extension of the
bag is prevented by projecting ribs e on the interior of the filter body or jacket.
As will be seen, the character of the invention consists in causing the bag to make
joint by its flange with the bottom of the vat or reservoir, in a similar manner to a
valve. This can also be realised with any of the arrangements used for ordinary
valves. For this it is only necessary to attach the bag, as represented at figures 6 to 8,
to a socket or ring B, arranged to make joint upon the opening in the bottom of the
vat or reservoir, either metal against metal, as shown in figure 8, or with the
interposition of leather, caoutchouc, asbestos, or other material, as represented in
figures 6 and 7, or again with the interposition of the edge of the bag itself
between the socket or ring and its seat, which arrangement is represented at.
figure 3.
The arrangements represented at figures 1, 2 and 5 are still the same, except that
in figures 1 and 2, the socket or ring is prolonged by an open-work basket or
envelope B. In the following examples this envelope, which prevents the undue
extension of the bag, is replaced by a metallic or textile net, as represented at figure 7,
or by an openwork basket or envelope suspended from the bottom of the vat or
reservoir, as represented at Figure 8.
In certain cases, where the filters are mounted on trunnions or pivots, or are subject
to movements, it might be feared that the oscillations of the case would detach the

page_text: valves from their seats; in this case it is convenient to fix them by a flanged cover E
(see figure 4) pierced with a central hole for the entry of the liquid, and held in
position by a cross bar H, which is introduced by lightly forcing it under the
angles F fixed to the sides of the vat or reservoir. The cross bar H holds all the
covers of the same row.
These covers have further the advantage, by contracting the entry of the liquid,
to prevent it from being projected against the surface of the filtering cloth, and to
disaggregate the animal black or other filtering material necessary for the filtration.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
In bag filters suspended below the vat or reservoir for the liquid, whatever may
be the arrangement of the details, which may be considerably varied, a means of
mounting the said bags, consisting in connecting them, by their upper edge, to a
socket or ring, forming a valve, either by itself, or by the addition of an elastic
fitting, which may be the bag itself, and closing the opening formed in the bottom
of the vat or reservoir to allow of the passage of the bag, which is introduced from
above.
B. J. B. MILLS.
By Harris & Mills,
23, Southampton Buildings, Agents.
B. J. B. MILLS.
By Harris & Mills,
23, Southampton Buildings, Agents.