IMPROVEMENTS IN VACUUM BOXES FOR PAPER MAKING MACHINERY PROVISIONAL SPECIFICATION
Year: 1883

page_text: LETTERS PATENT to Horatio Marsden and Henry Schofield both of Sheffield in
the County of York for an Invention of "IMPROVEMENTS IN VACUUM BOXES
FOR PAPER MAKING MACHINERY
PROVISIONAL SPECIFICATION left by the said Horatio Marsden and Henry
Schofield at the Office of the Commissioners of Patents on the 13th July
1883.
HORATIO MARSDEN and HENRY SCHOFIELD, both of Sheffield in the County of
York IMPROVEMENTS IN VACUUM BOXES FOR PAPER MAKING MACHINERY
"
"
Our invention relates to improvements in vacuum boxes, the object being to
extend the life of the wire gauze used in connection therewith, and thereby tend
to reduce the cost of the manufacture of paper.
The principal cause of the short life of the wire gauze, (which is used to
carry forward the wet pulp from the strainer to the rolls, the vacuum box being
between the two) is the friction caused by its being drawn over the stationary
edges of the box sides, while at the same time it is pulled tightly against them
by the suction of the vacuuin chamber.
We are aware that to avoid this destructive friction, it has at various times been
proposed to use antifriction rollers to support the wire gauze above the edges of
the box, but by reason of the great difficulty in preserving the vacuum with the
use of rollers, so far as we are aware, no arrangement of rollers in combination
with vacuum boxes has proved a practical success or been of commercial utility
Our invention overcomes the difficulty and enables antifriction rollers to be
applied to vacuum boxes, and used with great advantage and economy.
In carrying out our invention, we form a water trough of the full length of the
box or thereabouts, against each of the inner sides of the box, the space between
the two troughs being the vacuum chamber, and in each of these troughs is fixed
a roller, supported by, and free to revolve in bearings at each end-The tops of the
rollers are raised high enough to carry the wire gauze clear of the edges of the
box sides, and they may be driven by suitable gearing from the outside of
he box.

page_text: We keep the troughs filled with a stream of running water, reaching nearly to
the top of the rollers, for the double purpose of keeping the rollers clean, and to
preserve the vacuum. The sides of the troughs next to the Vacuum Chamber, are
either hinged at the lower edge, or are made pliable or sufficiently elastic, so that
they can be forced towards the rollers by the action of compressed spiral springs
placed between the two sides.
The tops of these hinged sides are provided with removeable tongues or strips
of indiarubber or other clastic material shaped on the underside to fit closely
against the convex surface of the rollers against which they are pressed by the
action of the beforementioned springs This arrangement of the various parts as
described, effectually retains the vacuum and prevents the friction and abrasion
of the endless web of wire gauze.

page_text: The moveable slide blocks K, K, for adjusting the width of the vacuum chamber,
have a topblock of rubber L, which is shaped to fit closely over the strips or
tongues I, and they are moved in the usual manner by the screws M, N, and the
rollers are preferably driven by the chain gearing O, but other driving gear may be
used if preferred.
As before stated we are aware that rollers have been adapted and applied to the
sides of vacuum boxes, (but without success) and therefore we do not claim the
application of antifriction rollers to vacuum boxes broadly, but what we do claim
as novel and original, and as the invention secured to us by the herein before in
part recited Letters Patent, is :-
First, In vacuum boxes as used in paper making machinery the combination with
antifriction rollers, of water troughs partly enclosing the said rollers, and
having inner sides which are moveable towards said rollers, and adjustable
springs tending to so move said insides; the upper edges of said insides
being provided with one or more strips or tongues of rubber or other elastic
material in contact with the rollers, substantially as hereinbefore described
and as illustrated.
Second, In vacuum boxes às used in paper making machinery, the herein before
described hinged, or flexile jointed, inner sides of the water troughs,
substantially as shown, for the purpose specified
In Witness whereof, I the said Henry Schofield for myself and on
behalf of Horatio Marsden have hereunto set my hand and seal this
10th day of January in the year of our Lord 1884.