IMPROVEMENTS IN STRAINERS OR ENVELOPES USED IN EXTRACTING LIQUIDS FROM VARIOUS SUBSTANCES
Year: 1871

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery
Lane, in the County of Middlesex, Patent Agent, for the Inven-
tion of "IMPROVEMENTS IN STRAINERS OR ENVELOPES USED IN EXTRACTING
LIQUIDS FROM VARIOUS SUBSTANCES."-A communication from abroad
by Jean Baptiste Dervieux, of 14, Rue Ferrandière, Lyons, France.
Sealed the 28th July 1871, and dated the 24th May 1871.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 24th May 1871.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN STRAINERS OR ENVELOPES USED IN
EXTRACTING LIQUIDS FROM VARIOUS SUBSTANCES," to be as follows:
This Invention relates to improvements in strainers or envelopes used
in extracting liquids from various substances, whereby a pervious
surface is obtained through which heat may freely pass, as also the
liquid to be extracted, without liability of the spaces contracting or

page_text: being closed up on the application of pressure, as is the case with the
strainers now in use.
The improvements consist in making said strainers of ligneous
vegetable substances, such as reeds, osiers, rushes, or wattles of various
degrees of flexibility, which I unite or weave together in the manner of
wicker or basket work, leaving intervals for the passage of the liquid.
Strainers when made of these materials do not easily lose their original
form under pressure, and are not liable to become clogged so as to close
up the spaces.
I make the strainers preferably of flexible round rods or wattles of
equal size, disposed parallel to each other and at just sufficient distance
apart for the liquid expressed to pass through; or I may make them
from round wood shaped for the purpose, and so produce a permanently
pervious, flexible, and incompressible surface.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 23rd November 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of May, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special licence
that I, the said Alexander Melville Clark, my executors, administrators,
and assigns, or such others as I, the said Alexander Melville Clark, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN STRAINERS OR ENVELOPES USED IN EXTRACTING LIQUIDS FROM VARIOUS SUB-
STANCES," a communication to me from abroad by Jean Baptiste Dervieux,
of 14, Rue Ferrandière, Lyons, France, upon the condition (amongst

page_text: others) that I, the said Alexander Melville Clark, my executors or
administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare the nature of the said Invention, 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 Sheet of Draw-
ings hereunto annexed, and to the letters and figures marked thereon
(that is to say):
:-
In order to extract by means of pressure the fluid matters contained
in substances of a more or less solid nature it is indispensable to ensure
a successful result that the mass to be operated on should be separated
into fractional parts, otherwise the fluids to be extracted would have
to pass through a considerable amount of material which has become
insolidated by the pressure before the liquid can be expressed at the
surface, which is then only obtained in small quantities when compared
with the amount of material operated on. Moreover the fluids to be
extracted from certain substances cannot be made to percolate freely
through the same by pressure except they are subjected to heat
and maintained at a certain temperature throughout the operation; but
although the heat will act on the outside of the mass it cannot be made
to penetrate to the centre, and hence again the necessity for the fractional
separation of the mass. This latter is effected by dividing the substances
in layers of nearly uniform thickness by means of metal plates, which
are made solid when the matters are to be pressed in a cold state,
or hollow with an interior steam circulation when heat is employed. If
the metal be applied directly on the matter under treatment the
mass remains as compact as before, and the exudation of the fluid is not
in the least facilitated, for this reason, it is necessary to interpose
between the metal and the substance under pressure some fabric or
body of a sufficiently pervious nature to allow not only of the heat
from the plates being freely communicated to the matters although the
plates are not in contact therewith, but also (and this more particular'y)
to afford a passage for and thus thus assist in expressing the fluids.

page_text: For this purpose different hair fabrics have been employed of varying
thicknesses, and termed "hairs" strainers or envelopes, but they answer
the purpose imperfectly, inasmuch as they are of too close a texture,
even when uncompressed, for the free transmission of heat and for the
passage of fluids, but when subjected to pressure the spaces in the
"hair" or envelope become contracted and impenetrable. On removing
the pressure the elasticity of the fabric is partially restored, but after
some time it is entirely lost and the strainer becomes so clogged
under the pressure as to be almost impervious both to heat and to the
fluids required to pass through.
This Invention relates to improvements in strainers or envelopes
used in extracting liquids from various substances, whereby a pervious
surface is obtained through which heat may freely pass, as also the
liquids to be extracted, without liability of the spaces contracting or
being closed up on the application of pressure, as is the case with
strainers now in use.
The improvements consist in making said strainers of ligneous
vegetable substances, such as reeds, osiers, rushes, or wattles of various
degrees of flexibility, which are united or woven in the manner of
wicker or basket work, leaving intervals for the passage of the liquid.
Strainers when made of these materials do not easily lose their original
form under pressure and are not liable to become clogged so as to close
up the spaces. The strainers, are preferably made of flexible round rods
or wattles of equal size disposed parallel to each other and at just
sufficient distances apart for the liquid expressed to pass through, or
they may be made from round wood shaped for the purpose, and so
produce a permanently pervious flexible, and incompressible surface.
DESCRIPTION OF DRAWING.
The annexed Drawing shows two examples of the improved strainers,
one of which is constructed of small round wood rods or bars disposed
transversely, while in the other the bars are disposed longitudinally,
although the strainers may be otherwise made to suit the plates and
presses in which they are to be employed. It will be understood that

page_text: end.
In the Drawing c, c, are the parallel rods or bars forming the
straining surface, a the top frame to which the rods are fixed, and b
the lower frame serving to unite the two plates forming a strainer.
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as the Invention to
be protected by the herein-before in part recited Letters Patent is, the
application as an economical substitute for strainers composed of hair
and other slightly pervious materials of strainers constructed of wood
rods or of ligneous materials, as herein-before specified, whereby increased
efficiency in their action is ensured and permanent penetrability is
obtained.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Twenty-third day of No-
vember, in the year of our Lord One thousand eight hundred
and seventy-one.
Witness,
JAS. O. DEWEY,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)