IMPROVEMENTS IN FILTER PRESSES
Year: 1878

page_text: LETTERS PATENT to John Bowing, of No. 184, Gresham House, Old Broad
Street, in the City of London, Manufacturing Chemist, for the Invention of
"IMPROVEMENTS IN FILTER PRESSES."
Sealed the 5th November 1878, and dated the 19th July 1878.
PROVISIONAL SPECIFICATION left by the said John Bowing at the Office
of the Commissioners of Patents on the 19th July 1878.
JOHN BOWING, of No. 184, Gresham House, Old Broad Street, in the City of
London, Manufacturing Chemist. "IMPROVEMENTS IN FILTER PRESSES."
My present Invention relates to further improvements founded on those described
in the Specification of former Letters Patent granted to me, and dated February 10th,
1877.
I construct an improved filtering chamber by employing rings formed of fibrous
or yielding material such as cotton, wool, flax, india-rubber, leather, or the like.
They are fixed on diaphragms or plates by being rivetted, bolted, or sewn thereto,
or are fastened in any other convenient manner. They coincide with the edge or
circumference of the diaphragm, and in fact form a thickened rim thereof.
The rings are in some cases simple rings, in others they are made compound, and
in fact consist of two rings, one, the outer, is equal in diameter to the diameter of
the diaphragm; the other, the inner, is of less diameter, so that between the
concentric rings when they are fixed in position on the edge of the diaphragm there
is an annular and vacant space. At a point in this space, which is lowest when
the compound cylinder is ready to work, a hole is cut, so that a continuous channel
or passage is formed from end to end of the filter press by means of these holes.
This channel is continued outwards through the rim of the centre chamber where
the point of outlet for the filtrate is formed.
In this form of my improved filter press the filtrate does not escape to the
outside, but only through the first or inner ring into the annular space, by which it
is conducted through the series of holes and finally to the centre outlet.

page_text: Where economy is desirable, and the escape of the filtrate from the edge of each
diaphragm is not objectionable, a simple form of filtering chamber is constructed by
employing simple instead of compound rings.
My improved filtering apparatus is bolted together in the following manner :-I
employ a centre tie rod or bolt which passes through the centre from end to end and
forms the axis of the filtering cylinder. To obtain the necessary strength for
resisting the internal pressure the solid ends are preferably of iron.
In those cases where definite chemical action takes place in the materials
operated upon, or when the further manipulation of the residue or filtrate renders
it necessary, the form and material of the apparatus may be varied.
In some cases I employ outside tie rods where it is advisable to prevent the
materials treated in the filtering chamber from coming in contact with metallic
surfaces.

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SPECIFICATION in pursuance of the conditions of the Letters Patent and of
an Order of the Lord Chancellor filed by the said John Bowing in the Great
Seal Patent Office on the 10th February 1879.
JOHN BOWING, of No. 184, Gresham House, Old Broad Street, in the City of
London, Manufacturing Chemist. "IMPROVEMENTS IN FILTER PRESSES."
I construct an improved filtering chamber by employing rings affixed to the faces
of the diaphragms or plates which divide the chamber into compartments, rings
formed of fibrous or yielding material such as cotton, hemp, wool, flax, india-rubber,
leather, or the like. They are fixed on the diaphragms or plates by being rivetted,
bolted, or sewn to their faces near their outer edges respectively, or are fastened
thereto in any other convenient manner. It follows that the outer edges of the
rings, which when made of fibrous materials are flat, coincide with the edges or
circumferences of the diaphragms respectively, and in fact form a thickened rim
thereof.
I find it advantageous to make the face of the ring sloping towards the centre of
the diaphragm, so that an obtuse angle, or bevel, or chamfer is thereby formed.
I in this case cause the cloth covering the diaphragm to pass over and cover the
ring instead of passing between the ring and-the diaphragm.
:
In some cases I use single rings, in others I use two rings. The external diameter
of the outer ring is equal to the diameter of the diaphragm. The inner ring has a
less diameter, so that between the concentric rings when they are fixed in position
on the respective faces of the diaphragms there is an annular and vacant space
between them.
The cloth which covers the faces of each diaphragm or plate does not extend
beyond the inner ring, and the annular space serves as a conducting channel for the
expressed liquid.
In order to make the channels communicate, suitable holes are cut in the plates
in the parts that are lowest wheu the filtering chamber is at work, and thereby a
continuous channel or passage is formed from end to end of the filter press by means
of these holes. This channel is continued outwards through the rim of the centre
chamber where the point of outlet for the filtrate is formed.
In this form of my improved filter press the filtrate does not escape to the
outside, but only through the first or inner ring into the annular space, by which it
is conducted through the above-mentioned series of holes and finally to the centre
outlet.
The use of the double rings and channels formed between them will enable any
liquid that is expressed from any materials to be collected and preserved when its
value renders it desirable to do so.
Where economy of working is desirable, and the escape of the filtrate from the
edge of each diaphragm is not objectionable, a simple form of filtering chamber is
constructed by employing single rings affixed as above mentioned to the faces of the
diaphragms respectively at their outer edges.
The use of the rings made of fibrous or yielding material enables me to
dispense with the use of the rigid rings mentioned in the Specification of my former
Patent, dated the Tenth day of February, One thousand eight hundred and
seventy-seven, as being made of wood or other suitable material when it is desired
to do so.
My improved filtering apparatus is bolted together in the following manner:-I
employ a centre tie rod or bolt which passes through the centre from end to end
and forms the axis of the filtering chamber. To obtain the necessary strength for
resisting the internal pressure the solid ends are preferably of iron.
In those cases where definite chemical action takes place in the materials operated
upon, or when the further manipulation of the residue or filtrate renders it
necessary, the form and material of the apparatus may be varied, as for instance,
when materials partly composed of acids are to be operated upon, the iron tie rods

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:
should be fixed outside the filtering chamber and the diaphragms should be made of
acid-resisting substances, such as glass, porcelain, or lead, or wood.
1. I claim the combination of parts forming my improved filtering press, con-
structed substantially as herein described.
2. I claim the use of rings made of fibrous or yielding material, such rings being
attached to the outer edges of the diaphragms of filtering presses, in the manner and
for the purposes substantially as herein described.
In witness whereof, I, the said John Bowing, have hereunto set my hand
and seal, this Tenth day of February, in the year of our Lord One
thousand eight hundred and seventy-nine.
Signed, sealed, and delivered)
in the presence of
:
JOHN ANDREWS,
32, Essex St., Strand,
Solicitor.
F. D. WHITMORE LOWE,
Clerk to Messrs. Lane and Andrews,
32, Essex St., Strand,
Solrs.
JNO. BOWING. (L.S.)