Process and Apparatus for Utilizing Solar Heat for the Distillation of Volatile Liquids, for Recovering Substances Dissolved in such in so-called Waterless Liquids, and for Obtaining Water Localities.
Year: 1888

page_text: Process and Apparatus for Utilizing Solar Heat for the Distillation
of Volatile Liquids, for Recovering Substances Dissolved in such
in so-called Waterless
Liquids, and for Obtaining Water
Localities.
I, THEODOR ZIEM, of the Observatoire Khédivial, of Cairo, Egypt, Gentleman, do
hereby declare the nature of my invention, and in what manner the same may be
performed, to be particularly described and ascertained in and by the following
statement :-
My process for the distillation of volatile liquids, which is especially useful in hot
countries, chiefly consists in causing the solar heat to act directly, that is to say
without the application of concave mirrors or analogous appliances, upon the liquid to be
distilled, and then condensing and collecting in a suitable manner the vapours arising
from the liquid.
The apparatus for the distillation of water comprises a shallow tank or receptacle,
the sides and bottom of which are protected from loss of heat towards the surrounding
medium in a suitable manner by bad conductors of heat. This receptacle is covered
with an inclined glass roof (preferably at a gradient of 1:10). The frame holding
the glass plates is provided with grooves in such a manner that the drops of con-
densed liquid which are formed on the inside of the glass plates as soon as the
temperature is higher inside than outside, will be conducted to a collecting tank.
I have used my process with advantage also for the rectification of alcohol, pro-
ducing in the first instance alcohol of 72 per cent. from alcohol of 12 per cent. by four
successive distillations.
For this purpose, I have modified my apparatus as illustrated by the accompanying
drawings, but it will be understood, that the construction of the apparatus may vary
according to the special purpose for which it is designed, without departing from the
principles of my invention.
A is a funnel shaped vessel of sheet metal terminating at the bottom in a short
cylindrical tube which is closed by a perforated stopper. Through this stopper passes
At a the vessel A passes
a pipe leading to a receptacle D placed under the vessel A.

page_text: through a wooden frame, so that the entire lower part of the vessel will be situated in
the shade. B is a vessel similar to A, but smaller and serving for the reception of
the alcoholic liquid to be distilled. The same is closed in the same manner by a
stopper, through which passes a discharge pipe extending down through the stopper
of A and provided with a stop cock. A glass cover C is secured to the vessel A by a
hermetically closing joint b and placed at an angle to the horizon. c is a pipe for the
admission of the alcoholic liquid to be distilled.
For dividing the distilled liquid into two parts of different strength or concentration,
I apply to the inside of A, and approximately level with the upper edge of B, a
slightly inclined gutter &, from which the weaker distillate flows off through a pipe e,
while a more alcoholic distillate descends into D.
With such a distilling apparatus having about + of a square metre of sectional
area, but no gutter d, I have obtained in this locality (under the 30th degree of
latitude) an average daily quantity of 1.5 litres of distillate.
It is evident, that the same method and a similar apparatus may be employed also
for recovering salts or heavy (comparatively non-volatile) liquids, which are dissolved
in or mixed with volatile liquids; the latter being distilled off by solar heat, while
the admixtures remain as a residue.
In order to obtain water in localities destitute of rain and water, I employ strongly
hygroscopic salts, (for instance a concentrated solution of calcic chloride) which are
placed in shallow open vessels or tanks and allowed to attract moisture from the
atmosphere, chiefly during the night, the water thus absorbed being subsequently
distilled off by solar heat in the manner described above. My experiments made in
this direction at the border of the desert near Cairo, during a period of nearly three
years, have led to results, which show, that my method of obtaining drinkable water
in the desert, is very valuable.
Having now particularly described the nature of my invention and in what manner
the same may be performed, I declare that I claim :-
:-
1. The distillation of water, by exposing the water to the direct influence of the sun
in vessels surrounded with bad conductors of heat and provided with an inclined glass
roof, and conducting the water which has been condensed on the glass roof, to the
exterior by a system of gutters or conduits.
2. The rectification or distillation of alcohol and other volatile liquids, and the
recovery of the solid or heavy liquid substances contained in such liquids, by exposing
said liquids to the influence of solar heat in the apparatus described above and
illustrated in the accompanying drawings, or in apparatus analogous thereto.
3. The process for obtaining water in hot and so-called waterless localities, which
consists in causing strongly hygroscopic salis, such as concentrated solutions of calcic
chloride, to absorb water from the atmosphere and subsequently distilling off the
water from the more dilute solution in the apparatus specified in claim 1, by means of
solar heat.
4. Distilling apparatus constructed and adapted to operate substantially as described
and illustrated.