A NOISELESS MOTION WITH IMPROVED ACTION TO COMMON FLAT STRAINERS FOR PAPER PULP
Year: 1882

page_text: LETTERS PATENT to William Muirhead of Linwood, near Paisley in the
County of Renfrew N.B. for an Invention of A NOISELESS MOTION WITH
IMPROVED ACTION TO COMMON FLAT STRAINERS FOR PAPER PULP
·PROVISIONAL SPECIFICATION, left by the said William Muirhead at the
Office of the Commissioners of Patents on the 30th October 1882.
WILLIAM MUIRHEAD, of, Linwood, near Paisley in the County of Renfrew N.B.
"A NOISELESS MOTION WITH IMPROVED ACTION TO COMMON FLAT STRAINERS FOR
PAPER PULP."
These improvements consist of using upon the driving shaft of any flat knotter
or strainer revolving cams not formed like a ratchet wheel as those now in general
use but with their surfaces formed to guide both the rising and falling movements
of the strainer frame, and thus to prevent noise; and in combination with these
cams, springs are used to keep the horns of the strainer fraine in close contact
with them to constrain the movement of the frame to conforin with the surface of
the cams and to prevent the horns jumping from contact with the cams by the
quick action necessary to be given to the frame.
The surface of the cams are formed with one, two or more parts on their
circumference at a farther distance from the centre than the other parts inter-
mediate to these, and when revolving they give the upward and regulate the
downward movement of the strainer frame and thus give an improved action by
which more pulp passes through the plates than by the tremulous action given by
the ratchet cams.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Muirhead in the Great Seal Patent Office on the
28th April 1883.
WILLIAM MUIRHEAD of Linwood near Paisley in the County of Renfrew N.B.
A NOISELESS MOTION WITH IMPROVED ACTION TO COMMON FLAT STRAINERS FOR
PAPER PULP.
The object of this Invention is to give an improved action to flat strainers for
paper pulp whereby they work almost noiseless and an increased quantity of pulp
can be passed through the cut plates.
In working flat strainers the jog action is usually given to the frame carrying
the cut plates by a revolving ratchet wheel or cam which raises the frame by
lifting the horns projecting from it over the side of the vat, and then letting them
drop upon supports fixed upon the edge of the vat..
This action is usually very noisy and for this reason is very objectionable, and
to obviate this I use upon the revolving shaft, cams with an undulating-surface-
upon which the horns of the frame are supported and which guide both the upward
and downward movements.
To constrain the movements of the horns to follow the undulations of the cams,
the horns are held down against the cams by means of springs attached to somo
stationary fixture such as the side of the vat. These springs may be made-of-steel-
in either a flat or spiral form or of any elastic material.
This arrangement when working is almost noiseless, and when the speed of the
shaft, the amount of lift given by the cams, and the working level in the vat are
proportionately adjusted, the amount of pulp passing through the plates is greater
than the quantity passing by the common ratchet action.
The accompanying drawings shew two forms of arranging these fittings upon
flat strainers. In Figures 1 and 2 the vat is marked A; the frame B carrying the
cut plates is suspended at D; the revolving shaft C; the cams G shewn with two
undulations upon the circumference, but there may be one, two, three or more
undulations and the speed of the shaft regulated accordingly.
Upon the horn E of the frame there is a socket F supporting it upon the cam,
and upon the edge of the vat there are two short standards K supporting the box H
containing a steel spiral spring which presses the piston L against the horn the
amount of pressure being regulated by the screw M.
In Figures 3 and tho vat is marked A; the cut plates are carried in the
wooden frame B which is suspended at D; the shaft C and cams G are the same
as described above, but in this case the socket F upon the horn E is combined
with the box H containing the spring. The spring is compressed by the piston L
and the amount of pressure regulated by the screw M passing through the bridle N
which is kept from rising by the flat hook strap K attached to the side of the vat,
and when the screw M is relieved from the piston L the bridle N can be turned
over clear of the horn to allow the frame being lifted for cleaning the vat and the
under side of the plates.
Having described these two arrangements as examples of the application of my
Invention, I do not claim any special arrangement of these parts, but I claim as
my Invention
The improved method of acting upon flat knotter plates vis: the employment
of cams with an undulating circumference to regulate the upward and downward

page_text: movements of the frame in combination with springs to constrain the frame to
follow in its movements the undulations on the circumference of the cams as
hereinbefore set forth and substantially as shown in the annexed drawings.
In witness whereof 1 the said William Muirhead have hereunto set my hand
and seal this Twenty fifth day of April in the year of our Lord One
thousand eight hundred and eighty three.
WILLIAM MUIRHEAD (L.S.)