Improvements in Evaporating and Concentrating Apparatus, particularly applicable for Concentrating Sulphuric Acid.
Year: 1893

page_text: Date of Application, 12th May, 1893-Accepted, 17th June, 1893
COMPLETE SPECIFICATION.
Improvements in Evaporating and Concentrating Apparatus,
particularly applicable for Concentrating Sulphuric Acid.
I, GEORG SIEBERT, Platinum Refinery of Hanau on the Main, in the Empire of
Germany, Refiner do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
These improvements relate essentially to the arrangement of an inclined con-
centrating apparatus with a stepped or terraced bottom so that the acid, or other
liquid, such for instance as water, which it is intended to evaporate, may fall or
flow down along the whole width of the apparatus, or along the whole of the
separate steps or terraces in a regular stream from above over or along the heated
steps or terraces, and collect at the bottom and run out, whilst the steam produced
rises upwards in an oblique direction over the steps or terraces and is carried off
by means of a pipe or the like above the inflow.
The advantages of this arrangement consist in the possibility of high con-
centration or in the rapid and non dangerous production of steam or vapour, because
the acids which are to be concentrated, or other liquids which are to be evaporated,
are spread out in extremely thin layers and come thoroughly in contact with the
heated steps or terraces. A further advantage is that by the use of this apparatus
a very considerable saving in fuel is effected, and also that large quantities of acids
or other liquids may be concentrated or evaporated by means of a considerably
smaller and less expensive apparatus.
On the accompanying drawing,-
Figure 1 shows a side view and at the same time a longitudinal section of this
improved apparatus.
Figure 2 shows a rear view of the apparatus.
Figures 3, 4 and 5 show a modification of the bottom of the evaporator.
An obliquely inclined vessel a, Figure 1, which provided at the upper end with
a dome b for catching and carrying off the steam or vapours and at its lower end
with a discharge opening i for the escape of the liquid, has throughout its breadth
and length a stepped or terraced bottom c, each separate step of which lies deeper
downwards as against its front edge than the one above it, that is to say, each step
is inclined backwards. At the upper face of the vessel a, Figures 1-5, an inlet
opening e is arranged which is surrounded at the outside with a basin d and is
protected internally by means of a screen or shade f.
The upper edges of the steps or terraces c may also if desired be provided with a
rib g, Figures 3, 4 and 5, in such a way that the ridges or ribs g, which are shorter
in length than the width of the steps or terraces, may be alternately connected right
and left with the vertical wall of the pan, so that a passage remains open alternately
at the right and left for the liquid entering at the top, towards the step or terrace
next below, and thus the liquid s, Figure 5, is forced to traverse the whole length
of the steps or terraces from right to left and vice versa.
The sulphuric acid or other liquids is first caused to pass into the basin d,
Figures 1, 2, 4 and 5, whereupon it flows through the opening e and against the
screen or shade f, and, issuing beneath the lowest edge of the screen or shade f, fills
the topmost terrace up to the front edge. From here it flows, in thorough contact
with the heated bottom c, either over the whole breadth of the step or terrace in a
very thin and evenly divided layer, or, traversing the whole length of the step or
terrace from right to left or vice versa, onto the next lower succeeding step or
terrace until it finally reaches the lowest end of the apparatus, accumulates there,
and runs out of the opening i. The steam or vapour developed rises over the steps

page_text: or terraces into the dome b, because its escape through the inlet opening e is barred
by means of the screen or shade f and the acid or other liquid itself forms a
hydraulic closing. The steam or vapour may be carried off from the dome b in any
suitable manner.
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. An evaporating or concentrating apparatus, more particularly for the con-
centration of sulphuric acid, consisting of a flat closed vessel a, the bottom c of
which has the form of steps inclined backward in such a way that the liquid which
it is intended to evaporate or concentrate, when inserted in the upper part of the
apparatus, will fill to the front edge the uppermost step or terrace of the
step shaped bottom thus formed, along its entire width, and from here, in constant
contact with the heated bottom, will flow down in the same way to the next
succeeding terrace, and so on to the lowest end of the apparatus.
2. The arrangement of sheet metal strips 9 which are fixed on the upper or front
edge of each step or terrace and at one end only to the vertical wall of the pan in
such a way that a passage is formed alternately to the right and left to the next
step or terrace lying at a lower level, so that the liquid s entering above must pass
over each step or terrace in its entire length from right to left or vice versa.
Dated this 11th day of May 1893.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.