IMPROVE. MENTS IN THE MANUFACTURE OR PRODUCTION OF WHITE LEAD, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN
Year: 1860

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, and of 166, Buchanan Street, in the City
of Glasgow, North Britain, Gentleman, for the Invention of "IMPROVE.
MENTS IN THE MANUFACTURE OR PRODUCTION OF WHITE LEAD, AND IN THE
MACHINERY OR APPARATUS EMPLOYED THEREIN."-A communication from
abroad by Georges Hyacinthe Ozouf, of 24, Ruc Meslay, Paris, in the
Empire of France.
Sealed tho 11th January 1861, and dated the 19th July 1860.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on the
19th July 1860.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF WHITE LEAD, AND IN THE
MACHINERY OR APPARATUS EMPLOYED THEREIN," a communication from abroad
by Georges Hyacinthe Ozouf, of 24, Rue Meslay, Paris, in the Empire of
France, to be as follows:-
This Invention relates to a peculiar system or mode of manufacturing or
producing white lead by the intervention of mechanical contrivances, whereby
a superior article is produced in a comparatively short space of time, and at
a diminished cost, thau heretofore.
According to this Invention white lead is produced by the decomposit on of
basic acetate of lead by means of carbonic acid gas. The Inventor proposes
to accelerate and more porfectly effect the admixture and decomposition by
[Price 8d.1

page_text: the aid of certain mechanical arrangements, consisting of one or more lift and
force
pumps worked by a steam engine or other prime mover, which pump or
pumps force into a suitable closed vessel, which the Inventor calls a separator
or precipitator, a solution of basic acetate of lead, and a current of carbonic
acid gas produced by the decomposition of a carbonate by an acid, such, for
example, as carbonate of lime with sulphuric or hydrochloric acid or carbonic
acid
Igas obtainedf rom any other source. By this means the carbonic acid gas
and the solution of basic acetate of lead become intimately mixed, the result
of such admixture being the instantaneous production of white lead in the
form of a fine precipitate. Any excess of carbonic acid gas existing in the
separator passes over into a vessel or gas receiver in connection with the
separator, where it is again forced into or mixed with the solution of basic
acetate of lead. The Inventor also proposes to adopt an important modi-
fication in the production of white lead, namely, that heeffects the precipitation
of carbonate of lead by passing a current of carbonic acid gas, together with
a solution of basic acetate of lead into a vessel which he calls an agitator, and
which consists of a closed cylinder containing an agitator moved by suitable
machinery. The contents of this vessel are thus kept powerfully agitated
during the production of the white lead. After such agitation the contents
are, by means of suitable pumps and arrangements, truusferred into what the
Inventor calls the separator. The finely divided white lead so produced and
held in suspension in the liquor or solution is run from the precipitator or
separator into suitable depositing vessels.

page_text: assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an Inven
tion for "IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF WHITE LEAD,
AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN," a communication
from abroad by Georges Hyacin the Ozouf, of 24, Rue Meslay, Paris, in the
Empire of France, upon the condition (amongst others) that I, the said John
Henry Johnson, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say :-
The said Invention relates to a peculiar system or mode of manufacturing
or producing white lead, whereby a superior article is produced as compared
with that obtained by the ordinarymethods hitherto adopted forobtaining white
lead by precipitating processes.
In carrying out this Invention three different systems may be adopted.
According to the first and second system it is proposed to force simultaneously,
by the aid of pressure or otherwise, the neutral tribasic acetate of lead and
carbonic acid gas into a suitable vessel, wherein the intimate admixture of the
two ingredients is effected by means of an agitator. Various means may be
adopted for effecting the simultaneous introduction of the basic acetates of
lead and carbonic acid gas into the vessel, and for agitating or mixing the
same, as also for the production of the carbonic acid gas. According to the
third system it is proposed to introduce the carbonic acid gas under pressure
into a closed vessel filled with the neutral tribasic acetate of lead, which is
introduced into this vessel as fast as it is required by means of a pump or
otherwise, the intimate admixture of the gas and the solution of the tribasic
acetate of lead being accomplished by any suitable agitator. Having accom-
plished the precipitation of the white lead by the processes above described,
it is proposed to adopt a drying apparatus, whereby the processes of preci-
pitating the white lead and drying the same may be carried on continuously.

page_text: The accompanying Sheet of Drawings illustrates the apparatus employed in
the manufacture of white lead according to one of the systems herein-before
referred to from which good results have been obtained.
Figure 1 represents a side elevation of the combined apparatus complete in
working order; one or more pumps X are mounted on a support V, and
driven by a belt a passed round the pulley b, fast on the shaft c, which also
carries a fly wheel . This fly wheel may be also used as a driving pulley if
desired; the shaft c being rotated actuates through the crank e, connecting
rodf, the plunger rodg of each pump X. This pump draws in simultaneously
the carbonic acid gas and the solution of the tribasic acetate of lead respec.
tively through the two suction pipes o and s, which both open beneath the
same suction valve at R. The carbonic acid gas is produced in the copper
vessel A in a manner similar to that which is adopted in the production of
carbonic acid gas for the manufacture of aerated liquids, but it may obviously
be obtained by any other suitable process. The carbonic acid gas passes from
the vessel A to the gasometer H by the pipe D, and is thence drawn off by
the pump X through the flexible pipe O secured to the top of the gasometer.
The solution of tribasic acetate of lead is prepared in the vessel B by the aid
of a vertical agitator C, which is driven by the pulley J and belt a' from any
convenient prime mover. A pipe N conveys the solution of the tribasic
acctate of lead to an intermediate receptacle T, in which the level of the
liquid is maintained at a given height by the float ball cock U; into this
receptacle T dips the suction pipe S of the pump. This pump X having
simultaneously drawn in the carbonic acid gas, and the solution of the tribasic
acetate of lead, forces them together through the pipe Q into the closed mixing
vessel L, which is provided with an agitator driven by a band all, passing
round the pulley Y, and actuated by the driving pulleys at Z. This agitator
affects the intimate admixture of the carbonic acid gas with the solution of
the tribasic and acetate of lead so as to thoroughly saturate the latter, thereby
causing the production of white lead in the form of a precipitate, which is
held in suspension. On opening the cock P the mixture enters the lower
portion of the separating vessel K, whilst the excess of carbonic acid gas
ascends and passes into the upper end of the vessel by the pipe Q'on opening
the cock G. The carbonic acid gas in excess returns to the gasometer by the
pipe E, and the liquid holding the white lead in suspension flows through the
pipe Winto the vessel I. This vessel or reservoir serves as a distributor of
the liquid to various depositing vessels wherein the precipitate is allowed to
fall, and whence it is collected in the form of a pure and superior white lead.
The mother liquor in the reservoir I is returned by pumps or otherwise to the

page_text: vessel B, and when mixed with a suitable quantity of litharge, again forms
the tribasic acetate of lead, which is to be treated in the manner above
described for the further production of white lead therefrom. It will be found
advantageous to add occasionally to the liquor a small quantity of acetic acid,
in order to compensate for the loss or waste occasioned during the process.
The precipitate white lead having been collected, may be dried by the
apparatus shown at Figures 2 and 3. It is placed in a hopper over a
hollow copper cylinder y, provided with a cover at each end, and turning on
a hollow axis t. This cylinder may be heated either by introducing steam or
hot air therein through the hollow axis, or it may be heated by a number of
gas burners arranged in any suitable and convenient manner. The cylinder y
is rotated slowly by the pulley u, and receives a layer of the white lead, which
is applied and spread evenly on to the whole length of its surface by the small
roller & as fast as it issues from the orificer in the hopper. The thickness of
this layer may be regulated by adjusting the rollers nearer to or further from
the surface of the drying cylinder by the aid of the screws p; m is a scraper
for removing the white lead which has had sufficient time to become
thoroughly dried between leaving the roller s and reaching the scraper. A
hood and chimney n carries off the vapour which rises from the drying sub-
stance, and the white lead is allowed to fall into small waggons 1, or other
receptacles placed there to receive it when it is ready for the market.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the saine is or may be used or carried
into effect, I would observe, in conclusion, that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,
First, the system or mode of manufacturing white lead, as herein-before
described.
Second, the general construction,arrangement,and combinationofapparatus
for manufacturing white lead, as herein-before described.
In witness whereof, I, the said John Henry Johnson, have hercunte set
my hand and seal, this Nineteenth day of January, One thousand
eight hundred and sixty-one.
J. HENRY JOHNSON. (L.S.)