IMPROVEMENTS IN PRODUCING COLD, AND IN THE MANUFACTURE OF SULPHUROUS ACID, AND IN ÅDDARAMITS PAD THESE PARROSES
Year: 1875

page_text: LETTERS PATENT to Raoul Pierre Pictet, residing at Geneva, in
Switzerland, Civil Engineer, for the Invention of "IMPROVEMENTS
IN PRODUCING COLD, AND IN THE MANUFACTURE OF SULPHUROUS ACID, AND IN
ÅDDARAMITS PAD THESE PARROSES "
Sealed the 16th October 1875, and dated the 3rd August 1875.
COMPLETE SPECIFICATION filed by the said Raoul Pierre Pictet
at the Office of the Commissioners of Patents, with bis Petition
and Declaration, on the 3rd August 1875, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RAOUL
PIERRE PICTET, residing at Geneva, in Switzerland, Civil Engineer,
send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN PRODUCING COLD, AND IN THE MANUFACTURE OF SULPHUROUS ACID, AND IN
APPARATUS FOR THESE PURPOSES," and have petitioned Her Majesty to grant
unto me, my executors, administrators, and assigns, Her Royal Letters

page_text: In the brickwork B is set a retort A of rather stout cast-iron, which
is provided with a flanged pipe, and inclines slightly upwards. Under
the retort there are two furnaces C, C³, about 1 metre apart. A
chimney D allows the products of combustion to escape at any con-
venient point. Either sulphurous vapours or a substance capable of
giving off vapours of sulphur are introduced into the retort, but by
preference I prefer to use sulphur, either in flour or sticks, say from 2
to 20 kilogrammes, according to the size of the retort. A small stream
of commercial sulphuric acid is introduced into the retort from any con-
venient reservoir through a safety tube a entering at the top of the
highest end of the retort This acid runs along the retort, and is
volatilized by the heat of the furnace O', and its vapour by reason of its
high temperature takes with it the vapour of sulphur This mixture
of vapours passes along the retort, and in passing the furnace C attains
a temperature of at least 300° centigrade Decomposition then takes
place, the sulphuric acid loses an equivalent of oxygen, which combines
with the sulphur and forms sulphurous acid, and at the same time
the sulphuric acid itself becomes sulphurous acid In this reaction
about 5 kilogrammes of sulphuric acid of commerce (66°) and about
1 kilogramme of sulphur are required to produce 6 kilogrammes of sul-
phurous acid.
In order to cleanse the gas as it leaves the retort of particles of
sulphur held in suspension it is caused to ascend along an inclined
pipe E, where it deposits the undecomposed sulphur or sulphuric acid,
which again descends into the retort.
Although it is not indispensable I prefer, to ensure greater success in
the operation, to use the sulphurous acid gas in an anhydrous state.
For this purpose it can be passed over any substance more or less hygro-
metric, such as chloride of calcium, chloide of sodium, &c., but, as
cheaper, I prefer to cause the gas to pass over a stream of sulphuric
acid in the slightly inclined washing tubes F, F, in which the sulphuric
acid, entering at one end and coming out at the other, absorbs in its
course all the vapour of water from the decomposed sulphuric acid.
The gas is then collected in an oil gasometer G, from whence it is with-
drawn by the pump H, and flows into the worm I, which is surrounded
with ice. The anhydrous sulphurous acid is thus condensed into a liquid,
which as it comes from the worm is stored in copper vessels provided
with a tight tap.

page_text: Lucie Smprovement
The Drawings sufficiently indicate the arrangement of the details of
the apparatus, and rendor unnecessary any fuller explanation A
vessel M. surrounded with ice is shown for condensing the greater part
of the water in the gas before it passes to the washing tubes, but this
detail is not essential. The gas thus liquified and stored may be used
for any purpose. I will now describe the way in which I propose to usc
it in the manufacture of ice.
The principle of the apparatus is the same as that already used with
other agents, and consists in producing cold by the evaporation of a
volatile liquid, but the apparatus is here considerably simplified.
The apparatus is shown in plan and elevation on Shoet II. of the
Drawings, and is composed of three parts.
1. The refrigerator, Figure 1, in which the congelation is produced by
the volatilization of the liquid sulphurous acid It consists in a copper
or iron tubular boiler A of ordinary construction, jacketted and having
tight joints. The liquid sulphurous acid is introduced into the boiler
by the opening a and circulates among the tubes, which it surrounds,
and then as it volatilizes it is sucked up the ascending tube B. A salinc
solution, such as will not freeze until 15° or 20° of cold circulates in the
interior. A screw C placed in front of the tube plate and driven in any
convenient way causes the salt water to circulato very rapidly, so that
all the tanks of the refrigerator are in a bath as cold as possible. This
rapidity of circulation is one of the important elements of success in the
operation. Around the tubular boiler are disposed, as is seen in the
Drawing, sheet iron tanks containing the water to be frozen. These
tanks D contain from 10 to 20 litres, and are separated the one from the
other by spaces of a few millimetres, so as to allow the freezing liquor
to pass. The number of the tanks, it is unnecessary to say, depends on
the size of the machine. The cistern containing the tanks is protected
by a bad conducting jacket.
2. The double-acting suction and circulation pump is shown at
Figure 2. The sulphurous acid vapours resulting from the volatilization
of the liquid acid in the boiler A. of the refrigerator are sucked through
the pipe B by the pump, which receives them by the tube X and expels
them through the tube X' to the condenser herein-after described. The
pump is of ordinary construction, and is driven in any convenient way.
The stuffing box only requires a particular arrangement. As is seen at

page_text: Figure 4, the stuffing box of the piston rod is long, and has at its centre
a metallic ring, which divides the packing in two. At this ring there is a
small tube, which communicates with the suction pipe X of the pump, so
that the gas which has leaked through the packing is again sucked into
the pump, thereby materially reducing the loss. If desired the cylinder
and piston rod may be lubricated, but in this arrangement lubrication
may be dispensed with.
3. The Condenser, Figure 3. The sulphurous acid vapours forced out
by the pump are brought to the top of the condenser E by a tube having
on it the cock e. The condenser is tubular, and is shown in the Drawing
in a vertical position, but it may be in any other position, or may bo
replaced by a worm of iron, copper, or other metal. A stream of water,
either fresh or salt, constantly circulates around the worm in the
opposite direction to the flow of the gas, say, entering at e³ and flowing
out at e³, so as to absorb the heat given off by the condensation of tho
sulphurous acid vapour. The acid is liquified by the pressure of the
pump, and descends to the bottom of the condenser. At the bottom of
the condenser there is a discharge cock e', through which the liquified
acid passes into a copper or iron receptacle G, in which there is a small
cylinder or sphere carrying a stem, which closes a small orifice at the
bottom. This float is balanced by a spring, and as the condensed sul-
phurous acid rises more and more up the float until the line of floatation
is reached, when the stem rises, and opening the orifice allows the
liquid to escape by the opening, and to return to the refrigerator by the
closed tube H. The sulphurous acid is thus constantly recondensed, and
the quantity required to replace leakage is very small.
Tho Drawing shows the arrangements of connections, but it must be
understood that these arrangements may be modified according to cir-
cumstances, for on board ship I use an apparatus which is identical in
principle but differs slightly in its arrangement, as is shown on
Sheet III. of the Drawings. The parts corresponding to those on
Sheet II. are marked with the same letters. Here the exhaust and
circulating pump is driven directly by a small engine, as shown in the
Drawing. The cylinder P of the engine receives steam from the boiler,
and has a piston, whose rod Q carries a cross head and connecting rod,
driving a fly wheel in the usual manner, but the rod Q is also carried
back on the other side of the piston through the end of the cylinder and

page_text: serves as the piston rod of the pump R, which exhausts the sulphurous
vapous from the refrigerator, and forces them to the condenser.
The refrigerator and condenser I by preference place one above the
other, as indicated in the Drawing, both being horizontal and pointing
along the ship, thereby avoiding excessive agitation of the liquids, more i
especially the water in the freezing tanks.
Parallel partitions may also be introduced longitudinally, but not
going to the two ends, so as not to prevent the circulation of the salt
water, but at the same time limiting the effect of the rolls. The float is
in this case placed under the condenser.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that I do
not limit myself to the precise details of this description, but that what
I claim as my Invention is,―
First. The mode of manufacturing liquid sulphurous acid, substantially
as described and shown on Sheet I.
Second. The employment of liquid sulphurous acid in freezing
machines, substantially as described.
Third. The arrangement of freezing apparatus, substantially as
described and shown on Sheets II. and III.
In witness whereof, I, the said Raoul Pierre Pictet, have herc=
unto set my hand and seal, this Twenty-eighth day of July, in
the year of our Lord One thousand eight hundred and seventy-
fivc.
.