Apparatus for Removing Metallic Particles from Paper Pulp.
Year: 1888

page_text: Apparatus for Removing Metallic Particles from Paper Pulp.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, 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:-
In the manufacture of paper it frequently happens that fine metallic particles are
carried along in the pulp to the wire cylinder of the paper machine and form,
eventually an integral part of the paper, in which the presence of the metallic particles
forms a commercial defect. These metallic particles are mostly either of brass or
copper, or of iron, the iron particles being derived from the abrasion of the iron parts
of what are technically known as the engines, and the bronze or copper particles
being derived from some other parts of the machinery, such as bearings, or from the
vats and valves of water or steam pipes. One class of these particles namely those
which are copper, bronze lead, tin and the like are readily entangled and held by
mercury but mercury does not very readily attack, or at least very readily eat, ham-
mered, hardened or rolled copper, particularly if such rolled copper has the suboxide
face which is usual on hot worked copper.
The invention, therefore, consists in introducing between the pulp engines and the
vat from which the pulp is dipped by hand seive, or into which it runs to be taken
up by the cylinder of the ordinary paper machine, a trough in which the pulp, in its
passage from the engine to the vat, shall be exposed to magnetic and mercurial

page_text: influence, and also in the details of the construction of such trough, and of its
surroundings and accessories.
The trough is made of sheet copper, preferably in a single piece and slopes down-
ward from the engine to the pulp vat. It may be of any convenient length. The
slope of this copper trough is not a uniform slope but it is provided with what are
known in mining engineering as "riffles" or small dams which extend from side to
side. These riffles furnish pans of the width of the trough for the reception of
mercury, and between the riffles are placed magnets close up to the copper on the
trough. As the pulp flows down from the pulp engine to the vat, its flow will
be alternately accelerated and retarded, and consequently in a traverse over a
considerable number of riffles, almost every particle of the pulp, probably every
particle of the pulp, will have come within the magnetic field of the magnets, and
will have traversed the surface of the mercury in one of the mercurial receptacles.
In the accompanying drawings.
Figure 1 shows in elevation at E the pulp vat; at A is represented the bottom of
the trough of which B are the depressions which I have called riffles. c is the mercury
contained in these riffles, D represent the electro magnets placed between the riffles
and close to the bottom surface of the trough. A portion of the trough with its
riffles and mercury and an adjacent magnet is shown in Figure 2.
Figure 3 is a transverse section at the line x, x of Figure 2 and shows the trough
with its sides F F. Only two magnets placed at the centre of the trough are repre-
sented in Figure 3, but it is intended to place a series of magnets side by side across
the whole width of the trough, so that in the space between the riffles there shall be
no part of the trough which is not under magnetic influence or within the magnetic
field of some magnet.
The magnets which are employed are electro magnets, because with them great
magnetic power can be obtained.
When the mercury becomes too much saturated with the particles which it will
absorb and amalgamate it is to be drawn off and distilled in the usual way, and when
the delivery of pulp to the pulp vat ceases for any reason the surface of the trough
is to be cleaned from particles held to it by the influence of the magnets.
It is preferable to make a trough in a single piece without rivetting and to mount
the magnets on a movable slide so that they can be withdrawn during the process of
cleaning the trough, but these things are not absolutely essential to the working of
the invention; any other metal than copper, which is equally insusceptible to the
influence of mercury will serve to make the trough but it is not thought that a trough
made of iron would be as good as a trough made of copper, because the water of the
pulp would be apt to rust the iron and the iron would be apt to have residual
magnetism which would render it difficult to clean. It is for this reason that
non-magnetic sheet metal for the material of the trough is recommended.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to me
by my foreign Correspondent I declare that what I claim is :-
First In combination with a paper pulp vat, a pulp trough leading thereto,
composed of sheet copper, and provided with riffles B as shown and having arranged
beneath the said trough a series of electro magnets placed between the riffles below.
the bottom of the trough, substantially as described.
Second In combination with a pulp trough of a paper making apparatus, which
pulp trough is composed of sheet copper and is provided with riffles B, the pools of
mercury c in the riffles, substantially as described.
Third In combination with a sheet metal pulp trough provided with riffles B, the
mercurial pools C and electro magnets D, placed between the riffles, substantially as
described.
Fourth The improvement in apparatus for the manufacture of paper comprising
the pulp vat of the pulping engine and the pulp vat from which the sieves remove

page_text: the pulp in sheets or layers, and a pulp trough interposed between the said pulp vats
having a sheet copper bottom along which the pulp is caused to flow, which copper
bottom is wrought with riffles containing mercury in their cavities, and a series of
electro magnets, below said copper bottom, the magnetic fields whereof extend across
said trough from side to side whereby the particles of magnetic metal and of metal
capable of amalgamation in the pulp are detained on or near the bottom of the pulp
trough, substantially as and for the purposes described.
T114
8711 1
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.