Improvements in the Mode of and Means for Removing and Preventing Scales or Incrustations in Steam Boilers.
Year: 1890

page_text: Date of Application, 6th May, 1890-Accepted, 7th June, 1890
COMPLETE SPECIFICATION (AMENDED).
Improvements in the Mode of and Means for Removing and
Preventing Scales or Incrustations in Steam Boilers.
We, JOHN DRAPER, Chemist, of 415 Thirty-Eighth Street, ALFRED HOLMGREN,
Consulting Engineer, of 283 Park Avenue, HENRY RITTER MOUNT, Gentleman,
of 88 McDonough Street, and JOHN BARNES, Manufacturer, of 208 Fourteenth Street,
all in Brooklyn, New York, United States of America, 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 :-
The chief object of our invention is to prevent the formation of scales or incrus-
tations in steam boilers and to remove scales already formed in boilers or boiler tubes,
and it consists essentially in placing mercury in the boiler, which, under pressure and
heat, forms a smooth and glassy coating over the entire interior surface of the boiler
sheets and tubes.
The formation of said coating is expedited by the use of bi-chloride of mercury
and, when boilers are supplied with fresh water, metallic sodium is used to advantage,
but the beneficial effect of our invention is attributable chiefly to the action of the
mercury in the boiler. The beneficial effect of mercury in a steam boiler we discovered
and have proven by experiments under various conditions. The use of the bi-chloride
of mercury in connection with mercury renders the process of coating more expeditious
and perfect. The metallic sodium assists in the process of coating, but it is of no
advantage when the boiler is supplied with salt or sea water, and, even when the
boiler is supplied with fresh water, the metallic sodium may be dispensed with and not
essentially impair the efficiency of the invention.
The best results have been obtained in tests by the use of about 90 per cent. of
mercury and 10 per cent. of bi-chloride of mercury, when the boiler is supplied with
sea water. When fresh water is supplied to the boiler, the proportions should be
about 87 per cent. of mercury, 10 per cent. of bi-chloride of mercury and 3 per cent. of
metallic sodium. The proportions requisite to produce the desired effect may vary
somewhat with the style of the boiler and the character of the water with which it is
supplied.
The quantity of the material to be used and frequency of application depends
upon varying conditions. We have ascertained by a series of experiments that two
pounds to each 100 horse-power will keep a boiler supplied with fresh water perfectly
clean for six months. In some conditions, it may be desirable to renew the applications
at shorter intervals. The engineer, by examination, will be able to determine when
it is necessary to apply more of the material.
In carrying our invention into practice, we find it preferable to first introduce the
bi-chloride of mercury into the boiler and, after the same becomes mixed with the
water, the mercury or mixture of mercury and metallic sodium is introduced in about
the aforesaid proportion. The mercury and metallic sodium are, when both are used,
preferably mixed before application, but these substances may be applied separately
without essentially impairing the effect.
The effect of impregnating the water with bi-chloride of mercury before placing the
mercury in the boiler, is a quicker and more general action. The bi-chloride of

page_text: mercury is easily dissolved in water and its affinity for iron and steel greatly expedites
the process of coating the interior surface of the boiler.
By experiments and observations, we have ascertained that the desired effect is
obtained by both chemical and mechanical action. The substances are distributed by
the motion of the water, and, by chemical action, form a union with the iron or
steel. The success of the process depends upon the heat and steam pressure in
the boiler.
The minute particles of mercury penetrate between the scales or incrustations
existing in a boiler and the surface of the boiler and by the action of the mercury or of
the water which follows the mercury, the scales are readily separated from the metal.
The mercury having an affinity for iron and steel, forms, under heat and pressure, a
coating of a smooth and glassy nature on the surface of the boiler, from which tho
scales are removed, or the surface of now boilers, thereby preventing rust or the
formation of scales or incrustations.
The metallic sodinin is added when fresh water is supplied to the boiler to assist the
conting and it acts as an amalgamator of the other two substances.
The substances used in our process have no injurious effect upon the metal with
which they come in contact and their use obviates all the objections inherent to the
menns heretofore employed for removing scales and preventing their formation in
steam boilers. The substances used that have been found efficient in removing scales
have proved injurious to the metal and caused the pitting or grooving of the plates
and tules. The other means tried with success have proved too expensive for general
introduction.
The process hereinbefore described is comparatively inexpensive. The specific
gravity of the mercury prevents its being carried away before the coating can be
formed. The application, which is made at long intervals, requires no special skill or
attention of the engineer. These substances, under the heat and pressure in the boiler,
rapidly form the coating, which being of a metallic nature, is a good conductor
of heat.
The advantage of having boilers kept clean are well known to engineers, among
which is the great saving in fuel, which we have proved by experiments long continued,
is effected by the use of our invention.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
First. The hereinbefore described mode of conting the surface of iron and steel by
the use of mercury, subjected to pressure and heat in a steam boiler.
Second. First. The hereinbefore described mode of coating steam boilers and tubes
by first mixing with the water contained in the boiler, bi-chloride of mercury and then
placing therein morcury, the substances being subjected to the heat and steam pressure.
in the boiler.
Third Second. The hereinbefore described mode of coating metal surfaces with
which the water and steam in a boiler come, in contact, consisting of the introduction
of hi-chloride of mercury and a composition of mercury and metallic sodium, the
whole being subjected to hoat and pressure in the boiler.
Fourth Third. The means for coating the surface of iron and steel, consisting of
morcury, bi-chloride of mercury and metallic sodium, used substantially in the manner
and proportions set forth.
Fifth Fourth. The combination, with water in a steam boiler, of mercury, bi-chloride
of mercury and metallic sodium or salt, the whole being subjected to heat to secure the
proper temperature and steam pressure for the purpose and substantially in tho
manner set forth.
1000