IMPROVE- MENTS IN THE MANUFACTURE OF SULPHATE OF AMMONIA AND APPARATUS TO BE USED IN THE SAID Manufacture
Year: 1878

page_text: LETTERS PATENT to Frank Clarke Hills, of the Chemical Works, Deptford, in
the County of Kent, Manufacturing Chemist, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF SULPHATE OF AMMONIA AND APPARATUS TO
BE USED IN THE SAID Manufacture.”
Sealed the 1st November 1878, and dated the 17th August 1878.
PROVISIONAL SPECIFICATION left by the said Frank Clarke Hills at the
Office of the Commissioners of Patents on the 17th August 1878.
FRANK CLARKE HILLS, of the Chemical Works, Deptford, in the County of Kent,
Manufacturing Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF
AMMONIA AND APPARATUS TO BE USED IN THE SAID MANUFACTURE."
My improvements in the manufacture of sulphate of ammonia consists in causing
the ammonia so to combine with the sulphuric acid, that at one stage of the process
there may be an excess of ammonia in the liquor, and at other stages an excess
of acid, so that the iron or arsenic, or both, contained in the acid may be pre-
cipitated.
A convenient apparatus for carrying out my said Invention consists of a com-
bination of three vapour-tight vessels or saturators of any convenient size, and
lined with lead and set at different levels, and so connected by pipes that the
liquor may run from the first saturator into the second, and from the second into
the third; the said pipes being so arranged that the liquor in each saturator may
be kept at a convenient height. When the ammoniacal liquor is being distilled,
the ammoniacal vapour is conveyed by pipes from the still into the first and
second saturators. The ends of these pipes, which should be perforated with small
holes, dip into the liquor in the said saturators and are covered by it.
The pipe from the still into the second saturator is provided with a valve or
stop-cock for the purpose of regulating the quantity of ammoniacal vapour to be
admitted from the still, and the gases escaping from this saturator are conveyed
by a pipe into the first saturator, the end of which pipe should be perforated with
small holes, and be covered with the liquor in the said saturator, which liquor

page_text: being acid takes up any ammonia that may pass into it. The first saturator is
connected with the reservoir of acid by a pipe.
The said apparatus is used and acts as follows:-At starting the first and third
saturators are charged with acid or with sulphate of ammonia liquor having an
excess of acid in it, and the second saturator is charged with liquor having an
excess of ammonia in it. The ammoniacal vapour from the still is then caused to
pass into the liquor in the first and second saturators, the quantity passing into the
second being so regulated that the liquor in it shall continue to have an excess of
ammonia kept in it, in order that any iron or arsenic held in solution by the acid
may be precipitated. While the ammoniacal vapour from the still is so passing
into the said saturators, sulphuric acid from the reservoir is admitted into the first
saturator to neutralize the ammoniacal vapour passing into it, and to keep the
liquor therein slightly acid.
As the sulphuric acid flows into the first saturator, the sulphate of ammonia
liquor formed flows therefrom into the second saturator, and thence into the third,
in which the liquor is again made slightly acid by a regulated stream of sulphuric
acid. From this saturator the liquor flows into settling tanks and is allowed to
settle, after which it is evaporated to obtain crystallized sulphate of ammonia.
The waste gases generated in the still and in the first and third saturators may
be conveyed away by pipes in any way desired. Liquid ammonia may be used in
the second saturator instead of ammoniacal vapour from the still to keep an excess
of ammonia in that vessel. By the arrangement of apparatus berein-before
described, the process may thus be carried on continuously.
For distilling the ammoniacal liquor or gas liquor, I prefer to use a modification
of the form of still known as a tower still or column still, the said modification
consisting in the substitution for the plates ordinarily used of troughs placed side
by side in rows one above the other, spaces being left between them for the steam
and vapour to rise.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frank Clarke Hills in the Great Seal Patent Office on the 31st
January 1879.
FRANK CLARKE HILLS, of the Chemical Works, Deptford, in the County of Kent,
Manufacturing Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF
AMMONIA AND APPARATUS TO BE USED IN THE SAID MANUFACTURE."
My improvements in the manufacture of sulphate of ammonia consist in causing
the ammonia so to combine with the sulphuric acid, that at one stage of the process
there may be an excess of ammonia in the liquor, and at other stages an excess of
acid, so that the iron, or arsenic, or both, contained in the acid may be precipitated.
A convenient apparatus for carrying out my Invention consists of a combination
of three vapour-tight vessels or saturators of any convenient size lined with lead,
and set at different levels, and so connected by pipes that the liquor may run from
the first saturator into the second, and from the second into the third, the said
pipes being so arranged that the liquor in each saturator may be kept at a con-
venient height. When the ammoniacal liquor is being distilled, the ammoniacal
vapour is conveyed by pipes from the still into the first and second saturators.
The ends of these pipes, which should be perforated with small holes, dip into the
liquor in the said saturators and are covered by it.
The pipe from the still into the second saturator is provided with a valve or stop-
cock, for the purpose of regulating the quantity of ammoniacal vapour to be
admitted from the still, and the gases escaping from this saturator are conveyed
by a pipe into the first saturator, the end of which pipe should be perforated with
small holes, and be covered by the liquor in the said saturator, which liquor being
acid takes up any ammonia that may pass into it. The first saturator is connected
with the reservoir of acid by a pipe.
The apparatus is used and acts as follows:-At starting the first and third
saturators are charged with acid or with sulphate of ammonia liquor having an
excess of acid in it, and the second saturator is charged with liquor having an
excess of ammonia in it. The ammoniacal vapour from the still is then caused to
pass into the liquor in the first and second saturators, the quantity passing into the
second being so regulated that the liquor in it shall continue to have an excess of
ammonia kept in it in order that any iron or arsenic held in solution by the said
acid may be precipitated. While the ammoniacal vapour from the still is so passing
into the said saturators, sulphuric acid from the reservoir is admitted into the first
saturator to neutralize the ammoniacal vapour passing into it, and to keep the
liquor therein with excess of acid.
As the sulphuric acid flows into the first saturator, the sulphate of ammonia
liquor formed flows therefrom into the second saturator, and thence into the third,
in which the liquor is kept slightly acid by a regulated stream of sulphuric acid.
From this saturator the liquor flows into settling tanks and is allowed to settle,
after which it is evaporated to obtain crystallized sulphate of ammonia.
The waste gases generated in the still and in the first and third saturators may
be conveyed away by pipes in any way desired. Liquid ammonia may be used in
the second saturator instead of ammoniacal vapour from the still, to keep an excess
of ammonia in that vessel. By the arrangement of apparatus herein-before
described, the process may thus be carried on continuously, and a great saving of
time and labour is thus effected.
For distilling the ammoniacal liquor or gas liquor I prefer to use a modification
of the form of still known as a tower still or column still, the said modification
consisting in the substitution for the plates or diaphragms ordinarily used of
troughs placed in the still side by side in rows, one set being placed abovo the other,
and spaces being left between them, through which spaces the steam and vapour
rise, and the liquor being distilled descends. Or instead of using the ordinary.

page_text: plates or diaphragms aforesaid alone in the still, or of using the aforesaid troughs
alone in the still, both plates and troughs may be used in the same still, the said
plates being placed between the rows of troughs.
Having thus described the nature of my Invention and the manner in which it
is to be performed, I wish it to be understood that I do not limit myself to the
precise details herein-before described, as they may be varied without departing
from the nature of my said Invention, but I claim as my said Invention manu-
facturing sulphate of ammonia, essentially as herein-before described.
In witness whereof, I, the said Frank Clarke Hills, have hereunto set my
hand and seal, this Twenty-ninth day of January, in the year of our Lord
One thousand eight hundred and seventy-nine.
F. C. HILLS. (L.S.)