Messrs. Laurent Bros. & Collot exhibited at the Paris Universal
Exhibition in 1878 a patented hydraulic apparatus styled a filtering
press, the principle and construction of which it will prove of interest
to describe. The apparatus is remarkable for its simplicity and ease of
manipulation, and is destined to find an application in most oil mills.
_Details of Structure_.--The filter, which is shown in detail in Figs.
5 to 7, is formed of two semicylindrical cast iron shells, F, that are
firmly united, and held by a strong iron band which is cleft at one
point in its circumference, and to which there is adapted a mechanism
permitting of loosening it slightly so as to facilitate the escape of
the oil-cake. Within these shells, F, there are grooves, a, which have
the arrangement shown by the partial section in Fig. 11, and through
which flows the oil expressed by pressure. To prevent the escape of the
material through these grooves or channels, the interior of the shells
is lined throughout with plates or strips of brass that fit very closely
together, and present a simple slit with chamfered edges opposite the
grooves. At the two joints of the shells four of these plates are
riveted two by two; all the others are movable, and rest, like the
pieces of an arch, against the fixed plates that form abutments. Each
half lining is thus held by means of a central plate, b' (Fig. 10), with
oblique edges, and which, being driven home by the top of the filter,
binds the whole tightly together. All these plates, which are slightly
notched at their upper part, rest on a small flange at the lower part of
the shells.
[Illustration: FILTERING PRESS FOR OLEAGINOUS SEEDS.--AUTOMATIC
INJECTION PUMP]
As regards their manufacture, these plates are cut out of sheets of
perfectly laminated brass, and are afterward set into a matrix to center
them properly. After the shells have been bored out, all the plates are
mounted therein so as to obtain a perfectly cylindrical and uniform
surface. The plates are then numbered and taken out; and, finally, a
slit with chamfered edges is cut longitudinally through them, save at
three points--two at the extremities and one at the middle. The plates
thereafter rest against each other only at these three points, and leave
at the chamfered places capillary openings just sufficient to give
passage to the oil, but not to the pressed paste, however fine it be.
As will be seen in Fig. 5, the points of contact are not in the same
horizontal plane, but are arranged spirally, so that the flow will not
be stopped at this place as it would be were these solid parts all at
the same height. The filter, F, is completed by two pieces that play an
important part. The first of these is a cast iron rim, J, which is set
into the upper edge, and forms a sort of lip whose internal diameter
corresponds exactly to the surface of the plates, b. This rim, J,
is cast in one piece, and carries on its circumference two small,
diametrically opposite iron studs, which are so placed that they may
engage in the groove, p, at the upper edge of the shells, F.
The second of the two pieces is a cast iron bottom, K, which works on a
hinge-joint, and which is perforated with a large number of holes for
giving passage to the oil that has traversed the hair cloth cushion of
which we shall speak further on. These holes must correspond accurately
with the radial conduits presented by plate, E, and through which flows
the oil to a circular channel running around this same piece. In order
to exactly maintain such a relation between the holes and channels, the
piece, E, is provided with a stirrup-iron, d, that passes around one of
the columns, C, of the hydraulic press.
The entire filter thus constructed is attached to one of the columns,
C', of the hydraulic press in such a way that it can revolve around it.
For this purpose, the column is surrounded by an iron sleeve, L, cast in
two pieces, and which in its lower position rests on the shoulder, e, of
the column. The filter is connected with the sleeve by means of screws,
as shown in Fig. 6.
We shall now describe the mechanism for loosening the band, I, and
moving the bottom, K.
The band, I (Figs. 5 to 9), is cleft at a point in its circumference
corresponding to one of the joints of the shell, F, and carries at each
side of the cleft a bearing in which turns freely a steel pin. One
of these latter, i, is cylindrical, and the other, j, has eccentric
extremities that are connected with the former by two small iron rods,
k and l. The upper extremity of the pin, j, is provided with a bent
lever-handle, M, and the lower one carries in its turn a small disk, m,
the use of which will be explained further on. It results from such an
arrangement that by acting on the lever, M, with the band, and by reason
of the eccentricity of the pin, j, the two extremities of the band,
I, may be made to approach or recede at the will of the operator. The
position of nearest approximation is limited by the abutting of the hook
at the end of the lever, M, against the side of the filter. This latter
position corresponds to the moment of charging the apparatus (Fig. 6),
while the contrary one indicates the moment that the oil cake falls
(Fig. 4). Although the separation is but a few millimeters, it is
sufficient for disengaging and allowing the cake to drop.
The movable bottom, K (Figs. 5 and 6), which closes the base of the
filter during the pressing, becomes detached and drops vertically (Figs.
3 and 4), when the filter is disengaged from the press, and the oil cake
is to be dropped out. To render the maneuver of this part easy, the
bottom is provided with a projecting piece, N, united by a bolt with
the band, I, and furnished with an articulated hand-lever, N', that
terminates in an appendage, q. The upper part of the hinge is provided
with a tail piece, q', under which the appendage q, places itself when
the bottom, K, is brought to its horizontal position. Consequently, when
the operator desires to let the bottom drop in the position shown by the
dotted line (Fig. 5), after the filter has been loosened, he moves
the lever, N, to the position shown by the dotted line (Fig. 6). The
appendage, q, then disengages itself from the tail piece, q', and the
bottom is thus enabled to assume a vertical position. As the bottom at
the time of charging would not be sufficiently supported if there merely
existed the lever and catch, it is further provided at its opposite
extremity with an appendage, r, which slides over a catch, r'. This
latter is attached to the disk, m, at the lower extremity of the pin, j
(Fig. 7), and takes exactly the proper position when the band is closed
at the moment of charging, but leaves it, on the contrary, when the band
is loosened to allow the oil cake to drop out.
As the lateral flow takes place through the interstices of the brass
lining, there is need of but one cushion on the bottom and another
at the top to hold the material to be pressed. The first is a simple
hair-cloth disk for preventing the seed from passing through the
perforations in the bottom plate; and the second, O, of which Figs. 12
and 13 represent a segment, is formed of three thicknesses of the same
material united at the edges by two flat iron circles, s, riveted
together. These circles, which are made to fit the inside diameter of
the shells very accurately, prevent any leakage of the oil around the
presser, G, and keep the hairs from getting caught between this piece
and the plates, b.
_Charging of the Filter_. (Figs. 14 and 15.)--The apparatus for charging
the filter is of the same capacity as the latter, and is made of
galvanized iron. It is placed on a slide at the aperture of the steam
kettle so as to receive the warm seed as it is thrown out by the
stirrer. When full, it is taken up by its handles, rested on the rim of
the filter, and its contents emptied therein.
_General Manipulation of the Press_.--Supposing the filter in the
position shown in Figs. 3 and 4, at the moment the seedcake is about to
drop out: the operator takes hold of the lock lever, N, with his left
hand, raises the bottom, K, to a horizontal position, and at the same
time fastens the bolt of the lever by turning it. He then seizes the
lever, M, with his right hand, and turns it so as to close the filter,
having care at the same time to support the extremity, r, of the bottom
with his left hand so that the catch, r', may pass under it when the
lever is manipulated. The bottom haircloth is then put in place, the
charge is thrown in, and its surface leveled, and the hair-cloth cushion
is laid on top. The filter is then revolved around the column so as to
bring it into the position shown in Fig. 1. The cock of the distributer
that admits water under pressure being turned on, the ram, D, rises,
carries with it the filter, and compresses the material against the
presser, G. At the end of from six to ten minutes the pressure-valve is
closed and the discharge-valve opened. The filter then slides down with
its socket along the column, C', till it reaches the shoulder, e, where
it rests. It is next swung around to the position shown in Fig. 3, and
emptied of its contents by a manipulation, the reverse of that described
for charging it. All these manipulations of charging and emptying
require no more than half a minute on the part of an experienced
workman.
The press under consideration is well adapted to the treatment of heated
seed paste, and has been very successfully employed for that purpose
in France, Belgium, and Holland. It succeeds equally well for the
extraction of oil from nuts. Referring to the drawings, the scales are
for Figures 1, 2, 3, 4, 14, 15, one fifteenth actual size; Figures 5, 6,
7, 8, 9, one-tenth; Figures 10, 11, 12, and 13, one-fifth.--_Machines,
Outils et Appareils_.
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