IMPROVEMENTS IN PAPER MAKING PROVISIONAL SPECIFICATION
Year: 1880

page_text: LETTERS PATENT to John Hawthorn, of Newtown, in the County of
Chester, Engineer, for an Invention of "IMPROVEMENTS IN PAPER MAKING
PROVISIONAL SPECIFICATION left by the said John Hawthorn at the Office
of the Commissioners of Patents on the 3rd September 1880.
JOHN HAWTHORN, of Newtown, in the County of Chester, Engineer.
"IMPROVEMENTS IN PAPER MAKING MACHINERY."
My Invention relates to the arrangements for withdrawing moisture from the
layer of pulp lying upon the travelling "wire" in the paper making machine. In
some machines the wire travels over "vacuum boxes," and is brought into contact
with the edges of the said boxes by the atmospheric pressure, and as the said boxes
are stationary whilst the "wire" is travelling, the frictional contact has the effect
of lessening the efficient durability of the wire. The object of my Invention is
to increase the durability of the said "wire," and to this end I interpose a pervious
apron between the wire and the vacuum box or boxes. I make the said apron of
any suitable perforated, or pervious, or porous material, but at present I consider
perforated vulcanised caoutchouc alone, or combined with strengthening material,
to be the most suitable fabric. The upper surface of the apron may be smooth,
or be corrugated or fluted, or be "honey-combed or formed with cells on or in
the upper surface. I consider a "honey-combed" formation to be suitable, that is to
say, an apron formed with suitably shaped cells, having a perforation in each cell,
each perforation extending through the apron. The apron is of an endless form,
and passes over rollers suitably arranged. The apron prevents the contact of the
"wire" with the edges of the boxes, and at the same time sustains the " wire"
against the atmospheric pressure to some extent. I prefer to provide the vacuum
boxes and the sliding partitions with facing strips of phosphor-bronze or other
suitably hard material. I round off the edges of the said strips, and I polish the
surfaces over which the apron travels. I also prefer to mount a carrying roller
close to each side of the vaccuum box.
"

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Hawthorn in the Great Seal Patent Office on the 2nd March
1881.
JOHN HAWTHORN, of Newtown, in the County of Chester, Engineer.
"IMPROVEMENTS IN PAPER MAKING MACHINERY."
My Invention relates to the arrangements for withdrawing moisture from the
layer of pulp lying upon the travelling "wire" in the paper-making machine. In
such machines the "wire" travels over" vacuum-boxes," and is brought into
contact with the edges of the said boxes by the atmospheric pressure, and as
the said boxes are stationary whilst the wire is travelling the frictional contact has
the effect of lessening the efficient durability of the "wire."
The object of my
Invention is to increase the durability of the "wire," and to this end I interpose a
pervious apron between the wire and the vacuum box or boxes. I make the said
apron of any suitable perforated, pervious, or porous material, but at present I
consider perforated vulcanised caoutchouc alone, or combined with strengthening
material, to be the most suitable fabric. The upper surface of the apron may be
smooth, or be corrugated or fluted, or be "honey-combed" or formed with cells on
or in the upper surface. I consider a "honey-combed" formation to be suitable,
that is to say, an apron formed with suitably shaped cells having a perforation in
each cell, each perforation extending through the apron. The apron is of an endless
form, and passes over rollers suitably arranged. The apron prevents the contact of
the "wire" with the edges of the boxes, and at the same time sustains the "wire "
against the atmospheric pressure to some extent. I prefer to provide the vacuum
boxes and the sliding partitions with facing strips of phosphor-bronze or other
suitably hard material. I round off the edges of the said strips, and I polish the
surfaces over which the apron travels. I also prefer to mount a carrying roller
close to each side of the vacuum box.
And in order that my Invention may be fully understood I have attached hereunto
a Sheet of Drawings made to a scale of about one and a half inches to the foot and
marked with letters of reference. Referring to the said Drawings, Fig. 1 represents an
end view of two vacuum boxes with my improvements applied thereto. In the said
Figs. A, A, are the two vacuum boxes; b represents the travelling wire, and c the
aforesaid apron. The two side edges of each box are faced with strips d of phosphor
bronze or other suitably hard material, and the faces of these strips are polished or
made smooth so that the apron will slide thereon with a minimum of friction and
wear and tear of the apron. The adjustable end a of each box is also provided
with a facing strip e which fits at each end against, and when adjusted slides
between, the strips d, d. Rollers ff, are situated as near as possible to the
strips d, d, and are formed or provided with journals which revolve in suitable
bearings, or the rollers are otherwise mounted to revolve easily. Other rollers g, g,
are arranged below the boxes and serve to keep the apron in a suitable state of
tension. One or each of the last named rollers may be adjustable in order that the
tension upon the apron may be regulated, and the rollers f, f¹, may also be
adjustable vertically so as to relieve the pressure of the apron upon the facing strips
to a suitable degree. The apron c travels with the wire over the rollers f, f¹, and
the facing strips d, d, and by being interposed between the wire and these parts
prevents the contact of the wire therewith, and the wire being no longer allowed
to have rubbing contact with the edges of the vacuum boxes is not worn so rapidly
and therefore remains longer in working order. As the apron and the wire pass
over the vacuum boxes the liquid is forced by the atmospheric pressure through
the interstices of the wire and through the pores or perforations of the apron into
the boxes, and the wire being pressed into close contact with the apron causes the
a

page_text: apron to travel at the same rate of motion as the wire, or if found necessary, any or
all of the rollers f, f¹, may be driven independently of the motion of the wire.
The rollers f¹ may be dispensed with if not considered to be necessary, and also
the rollers may be further removed from the sides of the vacuum boxes. By
substituting larger rollers or drums for the rollers f the lower rollers g, g, might be
dispensed with. The apron may be used in connection with one vacuum box only
or with more than two boxes, and may be used in connection with a box or with
boxes not provided with the facing strips d. Fig. 2 illustrates the appearance of
the face of the apron upon which the wire rests when the said apron is made of
vulcanised caoutchouc and moulded or formed with a honey-combed cellular
surface with a perforation in each cell; and Fig. 3 represents a portion of a similar
apron formed with square cells, having the four sides of the bottom of the cell
sloping in all directions to a central perforation.
Other formations of the apron
which may be considered to be suitable may be adopted in lieu of those indicated,
and also material other than caoutchouc may be used for the apron as hereinbefore
mentioned.
Having now fully set forth and indicated the nature of my said Invention, and
the manner in which I carry the same into practical effect, I would have it to be
understood that I claim,-
First. The combination and arrangement of parts, substantially as and for the
purpose set forth and indicated herein before, and in and by the accompanying
Drawings.
Secondly, The employment of a perforated or porous apron interposed between
the wire and the vacuum box or boxes, substantially as and for the purpose set
forth and indicated.
And, Lastly. The employment of an endless apron or belt of perforated vulcanised
caoutchouc, substantially as and for the purpose set forth and indicated.
In witness whereof, I, the said John Hawthorn, have hereunto set my hand
and seal, this First day of March, in the year of our Lord One thousand
eight hundred and eighty-one.
Signed, sealed, and delivered in
presence of
EDWARD K. DUTTON,
41, John Dalton Street,
Manchester.
(Agent for the Patentee.)
JOHN HAWTHORN. (LS.)