IMPROVEMENTS IN STRAINER PLATES FOR THE MANUFACTURE OF PAPER
Year: 1871

page_text: LETTERS PATENT to Henry Watson, of Newcastle-on-Tyne, in the
County of Northumberland, for the Invention of "IMPROVEMENTS IN
STRAINER PLATES FOR THE MANUFACTURE OF PAPER "
Sealed the 19th December 1871, and dated the 29th September 1871.
PROVISIONAL SPECIFICATION left by the said Henry Watson at the
Office of the Commissioners of Patents, with his Petition, on the
29th September 1871.
I, HENRY WATSON, of Newcastle-on-Tyne, in the County of
Northumberland, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STRAINER PLATES FOR THE MANUFACTURE OF PAPER," to
be as follows:-
.
:-
My improvement consists in covering the upper and wearing parts
either with the same or different metal by the electrotype or plating
process, or otherwise covering the wearing parts with a layer of other
material, so making the plates smoother as well as causing them to wear
longer. Also, when worn, the same method can be applied to restore
them, so that they can be used for a much longer period than formerly.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Watson in the Great Seal Patent Office on
the 28th March 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
WATSON, of Newcastle-on-Tyne, in the County of Northumberland, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of September, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Henry Watson, Her special license
that I, the said Henry Watson, my executors, administrators, and
assigns, or such others as I, the said Henry Watson, 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
STRAINER PLATES FOR THE MANUFACTURE OF PAPER," upon the condition
(amongst others) that I, the said Henry Watson, 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 Henry Watson, 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 thereof, that is to say :-
Heretofore the strainer or knotter for straining paper pulp in the
manufacture of paper has been made up of several plates, usually of
brass, each having numerous parellel and extremely fine slits cut in it,
through which the pulp is drawn to separate it from knots or lumps.
After such plates have been in use for some time the fine slits become

page_text: enlarged in places, and consequently the pulp drawn through the plates
is more or less contaminated with knots, and after a time the plates have
to be replaced with new ones. In some cases the plates when they
have become worn have been hammered on the surface to contract the
mouths of the slits, and the slits have again been brought to an even
width by passing a fine saw along them. This process however of
renewing the plates is both imperfect and expensive.
According to my Invention, I cover the upper and wearing parts of
the strainer plates by the electrotype process with a harder metal than
that of which the plate is composed, by which means I obtain strainer
or knotter plates which will wear much longer than those heretofore
used.
I prefer to form the knotter plates as heretofore of brass, and to coat
the upper and wearing parts with silver. The parts of the plates which
are not required to be coated may be covered over by a suitable varnish
before immersing the plates in the electrotype bath. In the same
manner also, after the plates have become worn, I am enabled, by
again coating them with copper or silver, or other suitable metal by the
electrotype process, to render them again fit for use, as the slits can be
contracted to any extent desired, according to the thickness of coating
deposited upon them. The slits may if desired be reduced to an even
width by passing a fine saw along them either before or after applying
the electrotype coating.
When the strainer plates are each made up of numerous parallel bars
or strips tied together by tie bolts, and with narrow spaces left between
the several strips, the wearing surfaces of the strips may similarly be
coated with a harder metal to render them more durable.
In witness whereof, I, the said Henry Watson, have hereunto set
my hand and seal, this Twenty-seventh day of March, in the year
of our Lord One thousand eight hundred and seventy-two.
HENRY WATSON. (L.S.).