IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR THE MANUFACTURE OF SULPHATE OF PROVISIONAL SPECIFICATION OF SULPHATE OF AMMONIA CHIEFLY ADAPTED FOR SMALL GAS- WORKS.
Year: 1882

page_text: LETTERS PATENT to John Dempster, of the Hollies, Elland, in the county of
York, Consulting Gas Engineer, for an invention of "IMPROVEMENTS IN
THE METHOD OF AND APPARATUS FOR THE MANUFACTURE OF SULPHATE OF
PROVISIONAL SPECIFICATION left by the said John Dempster at the
Office of the Commissioners of Patents on the 25th February 1882.
JOHN DEMPSTER of the Hollies, Elland, in the County of York, Consulting Gas
"IMPROVEMENTS IN
Engineer,
THE METHOD OF AND APPARATUS FOR THE
MANUFACTURE OF SULPHATE OF AMMONIA CHIEFLY ADAPTED FOR SMALL GAS-
WORKS.
JJ
This Invention relates to improvements in the method of and apparatus to be
employed in the manufacture of sulphate of ammonia chiefly adapted for small
gas works.
The apparatus consists of a boiler or still for containing the ammoniacal liquor
and a second vessel or saturator for containing sulphuric acid.
The still is constructed after the manner of an ordinary vertical boiler without
internal tubes. It may be either stationary or mounted upon wheels so as to render
it portable.
The ammoniacal liquor is conveyed to the still by means of a pump and is kept at
a moderate heat for some hours so as to expel the free ammonia after which a
quantity of soda or lime is introduced and the heat raised to boiling point, thereby
liberating the whole of the ammonia which is conveyed by pipe to the saturator to
which is attached a drainer.
All noxious gases formed during the process are conveyed from the saturator back
to the fire box of the still and there consumed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Dempster in the Great Seal Patent Office on the 25th August
1882.
JOHN DEMPSTER of The Hollies, Elland, in the County of York, Consulting Gas
Engineer. "IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR THE
MANUFACTURE OF SULPHATE OF AMMONIA CHIEFLY ADAPTED FOR SMALL GAS
WORKS.
This Invention relates to improvements in the method of and apparatus to be
employed in the manufacture of sulphate of ammonia chiefly adapted for small
gas works.
In order that my Invention may be better understood reference is made to the
accompanying sheet of Drawings wherein Fig 1 is elevation of apparatus I employ
and Fig 2 plan view of same. A is the boiler or still for containing the ammoniacal
liquor and B is a saturator for containing sulphuric acid which is introduced at the
funnel C. The still is constructed after the manner of an ordinary boiler and may
be either stationary or mounted upon wheels so as to render it portable. The
ammoniacal liquor is conveyed to the still by means of a pump, and is kept at a
moderate heat for some hours so as to expel the free ammonia after which a quantity
of soda or lime is introduced and the heat raised to boiling point thereby liberating
the whole of the ammonia which is conveyed away by pipe D to the saturator. All
the noxious gases formed during the process are conveyed from the saturator B by
pipe E to the furnace of the still and there consumed.
In practice it is found that in beating the ammoniacal liquor in the still a certain
amount of steam is generated which escapes into the saturator along with the
ammoniacal gases thereby making a weak solution of "Mother liquor" which
prevents the precipitation of the salts contained therein. This however is overcome
by boiling the "Mother liquor" and evaporating the surplus water, and this is
accomplished by placing a coil F in the saturator (shewn in section in Fig 3) and
blowing steam therein, which is effected by closing the tap G and opening the
tap H, the steam in the said coiled pipe making its exit through the pipe E into
the furnace.
The method of working is as follows.
The still A is first filled with ammoniacal liquor and the saturator B partially
filled with sulphuric acid. Both taps G and H are closed until the pressure gauge I
indicates that the liquor in the still is at about 5 lb pressure when the tap G is
opened allowing the ammoniacal gases to pass into the saturator B. After the whole
of the ammonia is driven out of the still which is ascertained by test papers, the
tap G is closed and tap H opened allowing steam to pass through the coil F thereby
heating the "Mother liquor" to such a temperature as to generate steam and
evaporate the surplus water contained therein. The salts are afterwards "fished"
out onto the drainer in the usual way.
Having now shewn and described my Invention and the manner of putting the
same into practice I would have it understood that I do not confine myself to the
exact details herein shewn and described as the same may be varied without departing
from the main features thereof, but what I consider to be new and therefore claim
as my Invention is
The combination and arrangement of the parts as are substantially herein shewn

page_text: and described whereby the steam required for evaporating purposes in the saturator B
is obtained from the same vessel that is employed for heating the ammoniacal
liquor.
In witness whereof I, the said John Dempster have hereunto set my hand
and seal this twenty third day of August in the year of our Lord One
thousand eight hundred and eighty two.
JOHN DEMPSTER. (L.S.)