AN IMPROVEMENT IN DRYING PAPER
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
RUMNEY CRAWFORD, of Warden Paper Mill, in the County of Northumber-
land, Paper Maker, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Tenth day of July,
One thousand eight hundred and fifty, in the fourteenth year of Her reign.
did, for Herself, Her heirs and successors, give and grant unto me, the said
Robert Rumney Crawford, my exors, admors, and assigns, Her especial
license, full power, sole privilege and authority, that I, the said Robert
Rumney Crawford, my exors, admors, and assigns, or such others as I, the
said Robert Rumney Crawford, my exors, adiñors, or assigns, should at any
time agree with, and no others, from time to time and at all times during the
term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "AN IMPROVEMENT IN DRYING PAPER;" in which
said Letters Patent is contained a proviso that I, the said Robert Rumney
Crawford, shall cause a particular description of the nature of my said Inven-
tion, and in what manner the same is to be performed, by an instrument in
writing under my hand and seal, to be inrolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after the
date of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Robert Rumney Crawford, do hereby declare that the nature of my said
Invention, and in what manner the same is to be performed, are fully
described and ascertained in and by the following description thereof, reference
being had to the Drawings hereunto annexed, and to the figures and letters
marked thereon, that is to say :-
My Invention comprises a new mode of drying paper chiefly after it has
been sized, and this object I effect in the various ways herein described.
The plan which I adopt for drying paper in the web or in long lengths
consists of a series of flat tubes, through which the paper conducted by tapes
is passed, and in its progress through these tubes it is subjected to a stream of
air (warm air I prefer) which is forced through the tubes by a fan or other
machine which is or may be used for blowing air or for exhausting air.
Figure 1 represents a side elevation of the machinery I have found to answer
the purpose; Figure 2, a front elevation of the same; Figure 3, a longitudinal
section; Figure 4, a cross section at A, B, on Figure 3. a, a', u³, a³, a³, a³,
as, a², a³, a, a, a", Figure 3, are rollers of wood for conducting the paper
and tapes through the tubes. b, b', b, b³, and b, Figure 3, are the tubes
(which I prefer made of sheet zinc) supported by wood framing stiffened. by
ledgers shewn at c, c, c, c, c, c. d, d, Figure 3, represent the air boxes for
feeding the tubes, and e, e, the trunks for conveying the air from the blowing
machine to the air boxes d, d. Motion is given to the rollers a, a, by the
driving shaft A and band wheels C and D, Figures 1 and 2. A crossed strap
is passed partly round the pully or band wheel D and drives the roller a³ by
passing round the pulley E. A pulley L is keyed concentric with the pulley
E and drives a strap the pulley G which is keyed upon the spindle of the
roller a. This roller drives the roller a¹ a strap passing round the pullies
F and H. The pulley C drives by an open strap the rollers a", a³, and a", by
the pullies placed upon their spindles in a similar manner to the above.
k, k, k, k, Figure 4, are throttle valves placed on each side of the machine at
the months of the air boxes d, d; their use when closed is for preventing the
air from passing from the air trunks e, e, into the air boxes d, d, until the
paper is fairly introduced into the tubes. These valves are then opened, and
the air enters the air boxes, and from these boxes it passes into the tubes
travelling in the same direction as the paper. The paper (represented by the
blue line) to be dried is passed into the machine between the roller a and a²,
Figure 3, and the tapes (represented by the red line) firstly closing the
throttle vales at the mouth of the air box belonging to the tube b until the
paper has passed the apertures for the air at the points ff, in tube b, and

page_text: when it has so passed, the throttle valves are opened and the air is forced on
both sides of the sheet in the direction the paper is travelling, taking up and
carrying off the wet and moisture in the form of vapour and discharging it at
the end of the tube bat g, g. When the paper reaches the roller a', it is
passed beneath it into the tube b', and the tape h is passed round the roller a"
and returns to roller a. The paper in the tube b' has the air thrown on
both sides of the sheet, and the vapour is expelled at the end of the tube
at i, i. The paper is then passed into the tube be round the roller a',
and the tape j returns into the tube b round the roller a². This process is
repeated until the paper is passed through all the tubes of the machine andi
the paper is dry. In drying thin papers it may be found unnecessary to use.
all the tubes, as the paper may be found dry after it has passed through a
certain number of them, when the paper may be taken off and wound upon a
reel or passed through a cutting machine at pleasure. Hand-made papers-
and papers that are cut into sheets before they are sized are after sizing:
generally hung upon lines in rooms or lofts and dried in summer by the-
natural atmosphere, and in winter by dry air warmed by steam pipes, &c..
This mode is very expensive, and occupies a great deal of time; it also.
requires a considerable space to dry in. To obviate this I have invented:
certain methods of drying paper of this description by machinery, as herein-
after described..
My first plan is by using a machine constructed as before described, but
although I have dried such papers with the tapes passing round the rollers, yet
I prefer using nets or other reticulate or open sheets for conducting the paper
through the machine, and when the machine is used for drying paper in the
sheets the throttle valves are always open.
My second plan for drying paper in sheets is by using a series of reels
round which the paper passes between tapes, cords, nets, or reticulate sheets
to conduct it from reel to reel. Air, heated by steam pipes or any other
well-known means, rises against the surface of the paper and dries it.
Figure 1 (Sheet 2) represents a longitudinal sectional elevation of the ma-
chinery I have used for drying paper in sheets, and Figure 2 is a transverse
sectional elevation of the same. A, Figures 1 and 2, is a pulley which may be
driven by the strap B from any prime mover. This pulley is keyed upon the
spindle of the roller C. D, D¹, D2, D3, D4, D', and D, Figure 1, are reels-
or drums. E, Figure 1, is a tightening roller; and F, F', and F, are guide
rollers for conducting the tapes, cords, nets, or porous sheets through the
machine. G, G, Figures 1 and 2, are steam pipes for warming the air;. or
the air may be warmed by cockles, flues, or any other well-known means used

page_text: for that purpose, and which need not be particularly described. Motion is
given to the reels D, D', and by the endless tapes, cords, nets, or porous
sheets represented by the brown lines a, b, Figure 1, passing partly round
them and the roller C, which roller is driven by the pulley A and the strap B
worked by some prime mover. The paper c, c (represented by the blue line)
to be dried is placed between the conducting tapes, cords, nets, or porous
sheets at the roller E, and when the paper reaches the reel D it is held
-between the tapes, cords, nets, or porous sheets which conduct it over the reel
D', under the reel D³, over D³, under D*, over D, and under D, when the
endless tapes, cords, nets, or porous sheets separate, a passing over the guide
rollers F², F, and F, and 6 passes over and beneath the rollers C and E to
bring through more paper, and the dried paper is taken off the machine at
the roller C. During the time that the paper is passing through the machine,
it is subjected to the warm air from the steam pipes G, G, and the vapour rises
out of the top of the machine and is discharged into the atmosphere through
openings male for that purpose in the roof of the building. Although up to
this stage I have only spoken of drying sized paper, yet I have used the
machines thus described for drying water-leaf or paper before it has been
sized, and I find the paper so dried approaches more nearly in quality the
character of such papers when dried in lofts.
My third method of drying paper in sheets after they are sized is by using
metal cylinders heated by steam instead of using the reels or drums just
described in my second method of drying paper in sheets. In this case I
prefer coating all or some of the cylinders with felt cloth, wooden slips placed
a short distance apart, or with any material that is not a good conductor of
heat, which provents the size drying too rapidly on the surface of the paper;
but some paper of an inferior quality may be dried in coming in contact with
the metallic surfaces, excepting so far as it may be separated by the endless
tapes, cords, nets or sheets, which I always use with the metallic cylinders for
conducting the paper. Although the cylinder just mentioned may be driven by
the tapes, cords, nets, or porous cloths, yet I prefer driving them by a train of
wheelwork in the same manner that the cylinders of the well-known drying
machine is driven, and which machine is used for drying papers in long
lengths, and is generally placed at the end of the paper-making machine.
My fourth method of drying paper in sheets after they are sized is, by using
a single reel or drum of large diameter. This drum is turned at a slow rate.
The paper is kept to the surface of the reel by endless tapes, cords, nets, or
open sheets, and warmed air is allowed to rise against the surface of the paper
to dry it.
Instead of using the large reel just described, a heated metallic

page_text: cylinder can be used, the paper being retained upon its surface by the endless
tapes, cords, nets, or sheets; and whether the reel or the cylinder is used the
endless tapes, cords, nets, or porous sheets may be returned by guide and
conducting rollers in a similar manner to the tapes and guides of a printing
machine, or as described in the tubular machine in my first method of drying
papers.
In witness whereof, I, the said Robert Rumney Crawford, have here-
unto set my hand and seal, this Tenth day of January, in the year of
our Lord One thousand eight hundred and fifty-one.