IMPROVEMENTS IN STILLS FOR CONCENTRATING SULPHURIC ACID
Year: 1885

page_text: COMPLETE SPECIFICATION.
I CHARLES ANTONE BARTSCH, residing at 4 Bassick Avenue Bridgeport, in the
County of Fairfield and State of Connecticut in the United States of America
gentleman, do hereby declare the nature of my invention for IMPROVEMENTS IN
STILLS FOR CONCENTRATING SULPHURIC ACID" and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to stills for concentrating sulphuric acid and has for its
object to provide such a still as may be readily opened for inspection and which
moreover shall be more durable and less liable to foul than the ordinary platinum
still now in use and further, to furnish by my construction a still in which acid
may be concentrated to a very high degree of strength and with these ends in view
my invention consists, in the details of construction and combination of elements
hereinafter fully and in detail explained and then specifically designated by
the claims.
:
In order that those skilled in the art to which my invention appertains may more
fully understand its construction and operation I will proceed to describe the same
in detail referring by letter to the accompanying drawing forming a part of this
specification in which
Fig. 1 is a.side elevation of my improvement in position and with the equalizing
jar attached thereto.
Fig 2 a top view of the interior of the lower section of the still.
Similar letters denote like parts in both figures of the drawing.
A is a trough of platinum, semi-circular in cross section, and with rounded ends
rising from its bottom in a gradual curve to the top and B is a flange secured to A
near its top and extending around its periphery, leaving between its upper edge
and the edge of the trough, a gutter C. D is a cover similar in shape to A and of
such size as to fit readily over A and rest in gutter C. E is the inlet pipe through
which acid is admitted to the still and this I preferably locate near the top of
trough A.
F is the outlet for escaping fumes. G is an overflow pipe from the gutter. .H is
the main outlet leading into an equalizing jar whence the acid flows off through
pipe J into convenient receptacles This equalizing jar I preferably make from
two, receptacles one within the other as K L. The inner contains the acid and
through the outer jar is passed a stream of cold water. M is an iron bed-ring

page_text: within which the still is adapted to rest for exposure to the fire and support. I do
not necessarily make use of this ring for I can support the still at either end
thereof but the ring relieves the still from strain and is found convenient. The
still supported either by the ring or by the ends is exposed to the strong heat of
the furnace fire beneath. As will be seen by the drawing, the ends of the still are not
exposed to the action of the fire and the outlet pipe is not directly exposed to
the heat.
The equalizing jar is so placed that its outlet shall be in the same horizontal plane
with the level at which the acid is desired to be kept in the still.
Before commencing to distil, the gutter C in which the edge of cover D rests, is
filled with any liquid so as to form a seal against escaping fumes, and the equalizing
jar is filled with acid up to the level of its outlet.
The acid to be concentrated is then allowed to flow slowly into the still through
inlet E. The heat to which the still is exposed causes fumes to be thrown off and
evaporation to take place from the acid therein. A great proportion of these fumes
A certain
pass off through pipe F and are saved by condensation elsewhere.
amount of liquid collects upon the inner surface of the top of the still and trickles
down into the gutter in which the cover rests. This furnishes a continuous supply
of liquid to form a seal for the joint and any surplus is carried off by the small
outlet G. The main outlet is connected with the still at the point where the end
rise commences from the bottom and thus will carry off acid from the very lowest
portion of the still. Passing through the outlet, the acid enters the equalizing
jar at or near its base and the level of the outlet from the jar determines the
depth of acid in the still The pressure of the incoming stream of acid causes &
gradual flow into the equalizing jar from the still and also an outflow from
the jar.
By taking the acid from the jar of the still, only that of the greatest specific
gravity and consequent concentration flows off.
Heretofore platinum stills have ordinarily been made non-separable and with the
outlet at the height at which its contents was desired to be kept. Consequently
an accumulation of deposit which on account of its specific gravity could not pass
off through the outlet collected in the bottom of the still and burned fast to the
bottom thereof. The absence of an equalizing jar rendered the position of the
outlet above the bottom necessary. Stills of this description are intended only for
the concentration to a great degree of strength of acid already at a strength of at
least 65° Baumé, when it cannot be worked in apparatus of other material. Above
a strength of 651° Baumé the sulphurets of lead and iron contained in the acid
are precipitated and when accumulated in the bottom of the still have a tendency
to burn fast, obstruct the still and sometimes by unequal expansion to crack the
bottom. In my invention the outlet at the bottom of the still and without the direct
influence of the furnace heat not only takes that acid which is most highly
concentrated from the still but also carries off the precipitated sulphurets which
are deposited in the jar instead of burned. to the bottom of the still. I am well
aware that stills for this purpose have sometimes been made separable, but I do not
know that stills of a form practically cylindric have been made, other than as shown
in United States Patent to Willett N° 301,033.
While I think that the form of still shown in the drawing (nearly cylindric) is
the most advantageous I do not wish to be limited to that precise form in the
application of my invention, the gist of which rests in the idea of a separable
platinum still with a fluid seal joint and an outlet at its bottom, in connection with
which is used an equalizing jar of the construction hereinbefore set forth.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
'
1. In an apparatus for concentrating sulphuric acid, the combination with a
furnace, of a still extending outside of the furnace and having an outlet pipe

page_text: extending from the lowest part of the still and outside of the furnace substantially
as described.
2. In an apparatus for concentrating sulphuric acid, the combination with a still
having an outlet pipe at its lowest point, of an equalizing jar connected to the
still by said pipe whereby the depth of the acid in the still is determined by the jar
as set forth.
3. In an apparatus for concentrating sulphuric acid, the combination of a still,
practically cylindrical in form, a separable cover having an opening connected with
a condenser, an outlet pipe at the lowest point of the still and outside the fire box,
a jacketed equallizing jar connected to said pipe and an outlet for the said jar as
described.