IMPROVEMENTS IN THE MANUFACTURE OF STRAINER PLATES FOR STRAINING PULP
Year: 1883

page_text: LETTERS PATENT to George Tidcombe Junior of Watford in the County of
Herts Paper maker's Engineer for an Invention of IMPROVEMENTS IN THE
PROVISIONAL SPECIFICATION left by the said George Tidcombe, junior, at
the Office of the Commissioners of Patents on the 10th October 1883.
GEORGE TIDCOMBE Junior of Watford in the County of Herts paper maker's
Engineer IMPROVEMENTS IN THE MANUFACTURE OF STRAINER PLATES FOR
STRAINING PULP.
This invention relates to certain improvements in the manufacture of strainer
plates for straining pulp as used in the manufacture of paper the object being to
produce strainer plates with hardened or non-corrosive surface plates and to renew
the surface of old or worn surface plates.
In carrying the invention into practice I prepare a plate, which I call a
foundation plate with a series of cells or grooves upon the underside thereof
similarly to the cells or grooves produced in strainer plates of old construction,
said cells gradually narrowing down to the wearing or top surface-Upon these
foundation plates I superpose and attach a sheet of metal covering the cells and
then slit this covering plate, which is the wearing surface, by circular saws each
slit corresponding to its under cell-The covering plate will be of hard metal such
as hard rolled sheet brass or bronze or one or other of the non-oxidizable metals or
alloys such as phosphor bronze nickel bronze or otherwise, or it may be of pure
copper such as electro-copper but the rolling is employed in order to compress or
toughen the metal sheet
The covering plate so employed will present and form to the edges of the cells
of the foundation plate and to the upper wearing edges of the slits a hard and
lasting point of contact to the wearing action of the pulp being strained both upon
the upward and downward pulsating action of the pulp through the straining slits
and also forms a breaking or clearing edge for the purpose of preventing "strings
Secondly. I emply these wearing surface plates for renewing the wearing
surfaces of old plates and in this case I plane off or otherwise remove the worn
"

page_text: slitted surface down to the cells and then superpose and attach the new plates
and then slit them to the required guage and the hardened edges forming the
crown of the cells will break off and clear the fibre of the pulp and thereby prevent
the ordinary strings
Thirdly I may produce this new wearing surface upon the prepared plate by
means of electro deposition of metal upon or by successive dipping of the surface
of the prepared plate in molten metal or so called galvanic-bath and in these cases
the cells of the plate will be filled up with a backing of plaster or convenient
filling material so that the deposited metal shall be received upon the plate without
filling or spoiling the cells when the deposited metal covering or renewal surface is
produced of sufficient thickness the cells will be cleared and the surface will be
dressed and then slitted and finished as required

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Tidcombe, junior, in the Patent Office on the 10th April
1884.
GEORGE TIDCOMBE Junior of Watford in the County of Herts Paper Makers'
Engineer "IMPROVEMENTS IN THE MANUFACTURE OF STRAINERS FOR STRAINING
PULP
""
This Invention relates to certain improvements in the manufacture of straining
plates for straining pulp as used in the manufacture of paper the object being to
produce strainer plates with hardened or non corrosive surface plates and to renew
the surface of old or worn strainer plates.
In carrying the Invention into practice I prepare a plate which I call a foundation
plate with a series of cells or grooves upon the underside thereof similarly to the
cells or grooves produced in strainer plates of old construction said cells gradually
narrowing down to the wearing or top surface.
Upon these foundation plates I superpose and attach a sheet of metal covering
the cells and then slit this covering plate which is the wearing surface by circular
saws each slit corresponding to its under cell.
The covering plate will be of hard metal such as hard rolled sheet brass or
bronze or one or other of the non oxidizable metals or alloys such as phosphor
bronze nickle bronze or otherwise or it may be of pure copper such as electro
copper but the rolling is employed in order to compress or toughen the metal sheet.
The covering plate so employed will present and form to the edges of the cells
of the foundation plate and to the upper wearing edges of the slits a hard and
lasting point of contact to the wearing action of the pulp being strained both upon
the upward and downward pulsating action of the pulp through the straining slits
and also forms a breaking clearing edge for the purpose of preventing strings.
Secondly I employ these wearing surface plates for renewing the wearing
surfaces of old plates and in this case I plane off or otherwise remove the worn
slitted surface down to the cells and then superpose and attach the new plates
and then slit them to the required gauge and the hardened edges forming the
crown of the cells will break off and clear the fibre of the pulp and thereby prevent
the ordinary strings.
Thirdly I may produce this new wearing surface upon the prepared plate by
means of electro deposition of metal upon or by successive dipping of the surface
of the prepared plate in molten metal or so called galvanic bath and in these cases
the cells of the plate will be filled up with a backing of plaster or convenient
filling material so that the deposited metal shall be received upon the plate without
filling or spoiling the cells. When the deposited metal covering or renewal surface
is produced of sufficient thickness the cells will be cleared and the surface will be
dressed and then slitted and finished as required.
In the drawings annexed hereto there is illustrated the application of this
invention to some different forms of strainer plates.
Figs 1, 2, and 3 represent in sectional views portions of strainer plates of old
construction that is cast of one piece in metal (generally brass or copper) and celled
at a and slitted at 6 through the crown of the cells.
Figs 1, 2 and 3 represent in like views but according to this invention the
foundation plates properly celled at a before receiving the hard or non corrosive
metal wearing surface plate. The openings a¹ of the upper ends of the cells are
wider than the guage of the slits b.
Figs 1b, 2b and 35 represent the improved construction of plate with the wearing
surface plate superposed and attached in position and slitted at 6 the lower edges

page_text: of b¹ of the said slits 6 overhanging the top edges of the openings a¹ of the cells a
and so forming the beating and contact edges for the backward clearing action of
the pulp and the same thickness of plate is maintained and can be reused in the
strainer without refitting.
The right hand portions of Figs 1, 2 and 3 represent the top slitted portion of
the plate planed off just below the line of the slits b for renewal of the top surface
which after renewal as before described will form a plate identical with Figs 1b, 2b,
and 3b and here the crown of the cells a will be formed by overhanging edges bi
and slits b of the wearing surface plates.
Fig 4 represents the foundation plate with its cells filled in with the backing of
plaster c to form the even top surface d when the process of putting the wearing
surface plate on by electro deposition of metal of dipping the plate successively in
molten metal is practised.
In some instances this invention is applicable to very strong foundations where
great strain is used upon the plates such as for beating and pulping stuff directly
upon the bottoms of vats or pans for grinding the material from which the pulp is
to be made and also for the bottoms of brewers vats and so forth.
The plates
shewn in the drawings are such as are generally used.
I employ these plates in revolving strainers and to increase the effect of cutting
and beating the fibres of the pulp by the edges 61 so as to prevent formation of
strings and clots I give an alternating reversing action to the revolving strainer.
It is to be noted that in so constructing strainer plates in two parts that is with
the crown plate upon the foundation plate it is necessary to solder the parts
together so that the two parts shall be as one piece when finished that is without
any interstices and that the soldering shall take place between broad surfaces and
out of the way of the wearing action of the pulp and chemicals sometimes present
in the pulp this soldering I effect according to the Specification of Letters Patent
No 4242 Dated 6th September 1882 granted to me. In addition to this soldering
I do in some cases place rivets through the plates say at about a foot apart more
or less
Having now described the nature and particulars of the said Invention I claim
Firstly-The manufacture of a new strainer plate by the application of the wearing
surface plate of hard or non corrosive metal which is to be superposed and attached
upon a foundation plate prepared with cells as herein set forth and shown by the
drawings.
Secondly In the renewal of worn strainer plates the planing or cutting off of the
slitted crown portion of the plate down to and exposing the top portion a¹ of the
cells a and then superposing and attaching the overlaying wearing surface plate
which will when slitted form the strainer surface as herein described.
Thirdly In the manufacture of strainer plates or the renewal of old plates the
superposing of the top surface plate by electro deposition of metal or by dipping in
molten metal until the required thickness of metal is obtained which is then to be
slitted and finished as and for the purpose herein set forth.
In witness whereof I the said George Tidcombe Junior have hereunto set my
hand and seal this Ninth day of April in the year of Our Lord One thousand
eight hundred and eighty four
In the presence of
WALTER A. BARLOW
6 St. Paul's Churchyard
London, E.C. Patent Agent.
G. TIDCOMBE JNR.
(L.S.)