IMPROVEMENTS IN APPARATUS FOR SEPARATING AMMONIA FROM GASES AND VAPOURS AND IN TREATING THE SOLUTION OF AMMONIA SALTS SO OBTAINED
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Gavin Chapman at the Office of the
Commissioners of Patents on the 17th October 1883.
GAVIN CHAPMAN of Glasgow in the County of Lanark, North Britain,
Manufacturing Chemist "IMPROVEMENTS IN APPARATUS FOR SEPARATING AMMONIA
FROM GASES AND VAPOURS AND IN TREATING THE SOLUTION OF AMMONIA SALTS
SO OBTAINED"
This Invention is a further development of the Invention for which Letters
Patent bearing date the 17th December 1881 N° 5,523 were granted to the present
applicant and it has for its object-First to separate ammonia from the gases and
vapours from blast or mineral sinelting and other furnaces, coking ovens and other
branches of Art and manufacture in the gases and vapours proceeding from which
ammonia exists and Second to treat by an improved process the impure solution of
ammonia salts so separated
In carrying out the first part of the Invention the gases or vapours to be treated
are passed through one or a series of vessels or chambers each of which has an inlet
and an outlet for the gases or vapours the outlet of one vessel or chamber being
connected to the inlet of the next when more than one are used.
In each vessel or chamber one or more shafts is or are situated horizontally and
at right angles to the direction of the inlet and outlet and on these shafts a series
of flat and preferably circular vertical discs, diaphragms or plates are so secured
at short distances apart as to give a free space or passage for the gases or vapours
between them.
The lower part of each vessel or chamber contains a solution of sulphuric or
other acid and the entire surfaces of the vertical discs, diaphragms or plates are
kept constantly wetted when the apparatus is in operation by rotating the shaft
or shafts on which the discs, diaphragms or plates are secured at a suitable rate
of speed.
The effect of this arrangement is, that the discs, diaphragıns or plates, being in
the direction of the length of the vessel or chamber that is to say in the direction
in which the gases or vapours pass, the maximum of surface is presented to the
gases or vapours for the separation of the ammonia therefrom.
Water is added continually or from time to time to compensate for evaporation
caused by the heat of the gases or vapours.

page_text: In operating with a series of vessels or chambers the acid solution is from time
to time added to the last vessel or chamber and thence passes through any suitable
pipe or syphon arrangement through the other vessels or chambers becoming
more and more saturated in its course
When sufficiently saturated the liquor is withdrawn from the chamber or from
the first chamber of the series and under the Second part of this Invention it is
treated in any suitable vessels with an excess of alkali, liquid ammonia being
preferably employed as being most convenient and suitable for the purpose. Air
and steam are then forced, pumped or drawn through the vessels containing the
alkaline liquid in order to oxidize iron and other matters contained therein and
this being effected the liquid is allowed to settle and the clear supernatent liquor
drawn off. The remaining liquor is then filtered in any suitable filtering
apparatus, water being passed through the filter in order to wash out the salts of
ammonia. The whole liquor is then boiled down to its salts in the ordinary
manner.