IMPROVEMENTS IN THE MANUFACTURE OF MAGNESIA
Year: 1873

page_text: LETTERS PATENT to Robert Stirling Newall, of Washington Chemical
Works, Newcastle-on-Tyne, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF MAGNESIA."
Sealed the 12th September 1873, and dated the 13th May 1873.
PROVISIONAL SPECIFICATION left by the said Robert Stirling Newall
at the Office of the Commissioners of Patents, with his Petition,
on the 13th May 1873.
I, ROBERT STIRLING NEWALL, of Washington Chemical Works,
Newcastle-on-Tyne, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF MAGNESIA," to be as follows:―
My improvement consists in submitting the magnesia deposited in the
manner described in the Specification of the Patent of Hugh Lee
Pattinson, dated 24th September, 1841, or other magnesia, either in a dry
or partially dry state, to pressure in moulds, by which process it is.
rendered denser and tougher, and therefore more suitable for transport
than magnesia of the usual kind.
I operate in the following manner.. T toko the neoinitated

page_text: of any desired shape, and submit it to such pressure as is needed to
obtain the requisite amount of density or toughness.
If pulp or semi-dry magnesia is operated on I put a quantity into a
machine constructed like a brick or tile making machine, which forces
out the material either in the form of bricks or cylinders, and these are 5
to be delivered on to a revolving web, and carried by it into a drying
chamber through which a draught of heated air is passed. The moulded
magnesia is retained in this chamber long enough to dry it.
If the magnesia is wished to be in the form of lozenges, or cylinders,
or blocks of a given weight, I use a mould of the required shape, and 1
submit the magnesia to the required pressure, and then remove it from
the mould.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Robert Stirling Newall in the Great Seal Patent
Office on the 18th November 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
STIRLING NEWALL, of Washington Chemical Works, Newcastle-on-Tyne,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of May, in the year of our :
Lord One thousand eight hundred and seventy-three, in the thirty-sixth
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Robert Stirling Newall, Her special license
that I, the said Robert Stirling Newall, my executors, administrators,
and assigns, or such others as I, the said Robert Stirling Newall, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "Im-
PROVEMENTS IN THE MANUFACTURE OF MAGNESIA,” the condition (amongst
upon
others) that I, the said Robert Stirling Newall, my executors, or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of
1

page_text: the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Robert Stirling Newall, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement, reference being had to the Drawing
hereunto annexed, and to the letters and figures marked thereon (that
is to say):-
My improvement consists in submitting the magnesia deposited in the
manner described in the Specification of the Patent of Hugh Lee
Pattinson, dated Twenty-fourth September One thousand eight hundred
and forty-one, or other magnesia, either in a dry or partially dry state, to
pressure in moulds, by which process it is rendered denser and tougher,
and therefore more suitable for transport than magnesia of the usual kind.
I operate in the following manner:-I take the precipitated magnesia,
either dry or in the state of pulp, and place a quantity of it in a mould
of any desired shape, and submit it to such pressure as is needed to
obtain the requisite amount of density or toughness.
When treating pulp or semi-dry magnesia I submit it to pressure in a
machine constructed like a brick or drain tile making machine, which
will force out the material either in the form of bricks or cylinders, and
sever the moulded forms into suitable lengths. These are to be delivered
on to a revolving web, and carried by it into a drying chamber through
which a draft of heated air is passed. The moulded magnesia is
retained in this chamber long enough to dry it.
If the magnesia is wished to be in the form of lozenges, or cylinders,
or blocks of a given weight, I use a mould of the required shape, and
) submit the magnesia to the required pressure, and then remove it from
the mould.
In carrying out my Invention I use an arrangement of apparatus
similar to that illustrated by the accompanying Drawing.

page_text: The apparatus consists of a box or chamber A. formed of wood covered
with felt, or of other materials, so as to prevent as much as possible any
loss of heated air which is forced through the chamber. One end of it is
connected by a conduit C, a, which conveys the hot air from the heater.
This heater I prefer to be formed of tubes, as in Root's patent boiler, 5
through which steam of about three hundred degrees Fahrenheit, or any
other required temperature, is passed from a boiler. The heater is
placed in a chamber, and the air to be heated is blown by a fan amongst
the tubes, and passes outby the conduit C, a, to the drying chamber A.
There is a slide valve at 6 for letting on or shutting off the blast of 1
heated air. At the other end of the chamber A is a chimney A¹ for
carrying off the vapor from the blocks of magnesia which are being
dried. There is a valve at a* arranged for admitting the endless web D
carrying the blocks. This web passes round the drums E, F, through
the drying chamber from F to E, carrying the blocks to be dried, and 1
the web returns outside the chamber as shewn in the Drawing. It is
supported on rollers c inside the chamber between F' and E.
I form the blocks of magnesia in the following manner: -I have a
mould frame B, 4, 4, (shewn enlarged at Fig. 3), which is divided by
partitions into squares or other desired form. This is counterbalanced 20
by a weight 3, so that it can be raised from 5, 5, on which it rests, the
endless web D passing through between the two. 4, 4, is pressed by its
own weight or otherwise against 5, 5, with sufficient force to prevent
any of the fluid escaping except through the web, which I thus use as a
filter. The boiler G, near to F, contains the carbonate of magnesia in 20
water as produced in the Pattinson process. I allow a quantity of it to
run from the boiler into the mould frame 4, 4. The water filters through
the web and the supporting frame 5, 5, and passes to the waste spout 7,
and the magnesia is left in the squares of the mould frame 4, 4. The
mould frame 4, 4, is then lifted, and the blocks remain on the web. 30
Motion is given to the web by turning the drum E, which thus draws
the blocks from B to a*, after which the frame 4, 4, is let down again
on 5, 5, and another series of blocks is produced in a similar manner.
There is a slide valve at a* for directing the heated air and vapour up
the chimney A¹. The valves a* and 6 are raised when it is required to 35
allow the blocks between B and a* to be drawn into the drying chamber
A, and a corresponding lot to be drawn out at the dry end of the
chamber.

page_text: The current of heated air. blown from the heating chamber through the
conduit C, a, and amongst the blocks in the chamber dries them rapidly,
and by means of this apparatus a great saving of time, labour, and
material is effected.
When it is desired to render magnesia dense and tough I submit it to
pressure, and by way of illustration I shew at Fig. 3 a design for a
pressure frame. I fit into the frame 4, 4, a plunger 8, 8, sliding in
guides, with projections on its lower face corresponding to the squares
or other desired forms in the frame 4, 4. This plunger is connected by
a series of jointed levers 9, 9, to the head of the framing, and on the top
is fitted a hand lever 10, arranged so as to work the plunger up and
down. By this or other means pressure may be applied to magnesia
whether produced by the Pattinson or any other process.
I wish it to be understood that the drying apparatus and pressure
apparatus may be used independently of one another, and also that the
drying process may be used with blocks formed by any other process.
The moulding apparatus may also be used without the pressing plunger.
Having now described the nature of my Invention, and explained
the manner of carrying it into effect, I wish it to be understood that I
claim,-
1. Rendering magnesia tough and dense by submitting it to pressure.
2. The arrangement of apparatus for filtering and drying magnesia at
the same operation, so as to save time, labour, and material.
In witness whereof, I, the said Robert Stirling Newall, have here-
unto set my hand and seal, the Eleventh day of November in the
year of our Lord One thousand eight hundred and seventy-
thro