An Improved Process for the Treatment of Carbide of Calcium.
Year: 1896

page_text: Date of Application, 29th Sept., 1896-Accepted, 21st Nov., 1896
COMPLETE SPECIFICATION.
An Improved Process for the Treatment of Carbide of Calcium.
I, MARC PIERRE EMMANUEL LÉTANG of 272 Faubourg Saint-Honoré, Paris,
in the Republic of France, Doctor of Medicine, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention relates to a new or improved process for the treatment of carbide
of calcium destined to facilitate the use and the handling of this chemical in all its
practical applications and particularly for the manufacture of acetylene gas.
Common carbide of calcium has the defect of being very sensitive to the action
of dampness or of steam. Moreover it leaves as a residuum a layer of damp and
solid lime which cannot pass through the openings of the carbide receptacles of the
acetylene producing apparatus.
These two defects result in keeping up the evolution of the gas long after the
carbide ceases to be in direct contact with the water. To remedy these defects,
that is to say in order to preserve the carbide of calcium from the influence of
moisture or of steam and to dissolve the lime, (resulting from the decomposition
of the carbide of calcium) or to render the same at least liquid and hence to
promote its automatic elimination I proceed in the following manner :-I cover
the pieces of carbide with a protective coating or paint consisting chiefly of glucose
to which I add petroleum and carbonate of lime in powder. The following is the
formula for the paint which I prefer to use:-
The above indicated formula may be modified not only as regards the relative
proportions of the ingredients but also as regards their nature. Thus instead of
glucose I may use any other chemical capable of dissolving or liquefying lime, for
instance, sugar in either a crude or refined state, or the residuum from the
manufacture of sugar and from distilleries, lactose, honey, mannite, maltose, dextrine
and the like as well as mixtures and combinations of sugar together or with other
substances, in short all saccharine substances such as saccharates and sucrates. On
the other band, for petroleum the use of which is to preserve the carbide from the
action of steam or moisture, I may substitute vaseline, terebinth, varnish made
with shellac, with rosin, with india-rubber or with gutta percha or the like. In short
every other chemical capable of forming an impermeable coating.
Powdered carbonate of lime which is of secondary importance in the mixture
may be replaced by chalk, talc, sulphur, fine sand and the like.
It is obvious that it is not indispensable to cover in all cases the carbide piece by
piece, it may be thought preferable to join the more or less fine and numerous
fragments together. The preceding formula or any other similar formula may be
used for the manufacture of such material.
Instead of covering the carbide with a paint or coating it may be merely mixed
(after petroleum has been added thereto) with one or more of the above substances:
which are capable of dissolving or liquefying lime. These substances may be merely
dissolved in water..

page_text: The carbide may contain besides calcium other substances such as magnesium
or a magnesium salt without the above mentioned method ceasing to be applicable
thereto.
In order to facilitate the cleaning of the apparatus wherein the carbide of calcium
is decomposed it will be preferable to use glucose or the like.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
(1) The improved process for the treatment of carbide of calcium whereby the
pieces of the said calcium carbide or other carbide containing calcium are covered
with a protective coating or paint consisting essentially of glucose or of a product
capable of dissolving or liquefying lime as fast as it is produced, substantially as
and for the purpose described.
(2) In a process for the treatment of carbide of calcium the use of a protective
coating or paint consisting essentially of glucose or of a product capable of
dissolving or liquefying lime, of petroleum or the like and of an inert powder
such as carbonate of lime, as set forth.
(3) The process whereby small or large pieces of carbide of calcium are coated
and cemented together with a paint consisting essentially of glucose or other
analogous product, substantially as herein described.
(4) The process whereby carbide of calcium may be decomposed with glucose or
with a product having an analogous action which may be mixed with the carbide
or dissolved in the water used to react on the carbide or in any other suitable manner
so as to liquefy the lime and enable it to run automatically through the opening
of the carbide reservoirs of acetylene gas producing apparatus, substantially as
herein described.
(5) A process for the treatment of carbide of calcium or other carbides containing
calcium, substantially as herein before described.
Dated this 29th day of September 1896.
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent.