IMPROVEMENTS IN THE PREVENTION OR REMOVAL OF INCRUS- TATION IN STEAM BOILERS
Year: 1880

page_text: LETTERS PATENT to George Davies, of No. 4, St. Ann's Square, Manchester,
in the County of Lancaster, Consulting Engineer and Patent Agent, for an
Invention of "IMPROVEMENTS IN THE PREVENTION OR REMOVAL OF INCRUS-
TATION IN STEAM BOILERS." A communication from abroad by Alfred Cords
and August Deininger, of Berlin, in the Empire of Germany.
PROVISIONAL SPECIFICATION left by the said George Davies at the Office
of the Commissioners of Patents on the 16th April 1880.
THE
GEORGE DAVIES, of No. 4, St. Ann's Square, Manchester, in the County of
Lancaster, Consulting Engineer and Patent Agent. "IMPROVEMENTS IN
PREVENTION OR REMOVAL OF INCRUSTATION IN STEAM BOILERS." (A communi-
cation from abroad by Alfred Cords and August Deininger, of Berlin, in the
Empire of Germany).
The formation of incrustation in steam generators is caused by the adhesion of
matter separated by the evaporation of water, as also by sand and dilutions
mechanically introduced into the feed water. The composition of the scale thereby
formed as regards its relative quantity is various. It generally consists of carbonate
of lime and magnesia with admixtures of clay and dirt and sulphate of lime
(gypsum).
Scale in marine boilers principally consists of chloride of magnesium and
gypsum.
This porcelain like incrustation of amorphous cleavage precipitated upon the
boiler plate is of an extraordinary solid composition, and in it is found sulphate of
lime mechanically agglomerated in small pointed crystals.
In order to prevent this in many respects abnoxious formation without detriment
to the steam generator, it becomes necessary that the agglomeration of the same
in its composition be destroyed by a commutation of its original salts. These
salts of lime and magnesia previously insoluble and free of water which prove the
most active agents for the formation of scale and most difficult of removal have, to
be transmuted in the boiler into easily soluble combinations of salts, and in this

page_text: form only can they be retained in the water in their dissolved state. This change
from insoluble to easily soluble salts is effected by an addition to the feed water of
sulphate of iron (green vitriol).
Sulphate of iron without a mutual exchange of their salts will not detach acids
adhering to iron as the stronger base is also a neutral salt, which possessing a
sweetish inky taste scarcely reddens litmus paper.
By the combination of a solution of sulphate of iron with water in the boiler a
mutual transfer of the salts takes place.
The sulphuric acid separates from the sulphate of iron by virtue of its natural
affinity for the mixture of carbonate of lime and magnesia originally dissolved in
the water of the boiler; also in inarine boilers in connection with chlorine it forms
sulphate of lime and salts of magnesia with from two to twelve per cent. of water,
which remain dissolved as long as the feed water (which from time to time should
be renewed) is not too much contracted.
If formations of crystals of gypsum should still occur such crystals are enveloped
by the oxy-hydrate of iron, separated at the samo instant and retained by the
same out of combination and in a state of suspension.
By virtue of these salts retained in the water of the boiler in a dissolved or
suspended condition by the separation of a hydrate, and in consequence of the
mutual exchange of salts the formation of scale is avoided, incrustation prevented
without any damage to the boilers, and scale already formed is detached.
Other foreign matter such as clay and dirt mechanically introduced by the
feed water becomes enveloped by the oxy-hydrate of iron and is blown off from
the boiler when convenient, or otherwise removed from the same when not in
operation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Davies in the Great Seal Patent Office on the 16tl: October
1880.
GEORGE DAVIES, of No. 4, St. Ann's Square, Manchester, in the County of
Lancaster, Consulting Engineer and Patent Agent. "IMPROVEMENTS IN THE
PREVENTION OR REMOVAL OF INCRUSTATION IN STEAM BOILERS." A communi-
cation from abroad by Alfred Cords and August Deininger, of Berlin, in the
Empire of Germany.
The formation of incrustation in steam generators is caused by the adhesion of
matter separated by the evaporation of water, as also by sand and dilutions
mechanically introduced into the feed water. The composition of the scale
thereby formed as regards its relative quantity is various. It generally consists of
carbonate of lime and magnesia with admixtures of clay and dirt and sulphate of
lime (gypsum).
Scales in marine boilers principally consists of chloride of magnesium and
gypsum. This porcelain like incrustation of amorphous cleavage precipitated upon
the boiler plate is of an extraordinary solid composition, and in it is found
sulphate of lime mechanically agglomerated in small pointed crystals. In order
to prevent this in many respects obuoxious formation without detriment to the
steam generator, it becomes necessary that the agglomeration of the same in its
composition be destroyed by a commutation of its original salts. These salts of
lime and magnesia previously insoluble and free of water which prove the most
active agents for the formation of scales and most difficult of removal have to be
transmuted in the boiler into easily soluble combinations of salts, and in this form
only can they be retained in the water in their dissolved state. This change from
insoluble to easily soluble salts is effected by an addition to the feed water of
sulphate of iron (green vitriol.) Sulphate of iron without a mutual exchange of
their salts will not detach acids adhering to iron as the stronger base is also a
neutral salt, which possessing a sweetish inky taste scarcely reddens litmus paper.
By the combination of a solution of sulphate of iron with the water in the boiler
a mutual transfer of the salts takes place.
The sulphuric acid separates from the sulphate of iron by virtue of its natural
affinity for the mixture of carbonate of lime and magnesia originally dissolved in the
water of the boiler; also in marine boilers in connection with the chlorine it forms
sulphate of lime and salts of magnesia with from two to twelve per cent. of water,
which remain dissolved as long as the feed water (which from time to time should
be renewed) is not too much concentrated. If formations of crystals of gypsum
should still occur such crystals are enveloped by the hydrate of iron, separated at
the same instant and retained by the same out of combination and in a state of
suspension. By virtue of these salts retained in the water of the boiler in a
dissolved or suspended condition by the separation of a hydrate, and in consequence
of the mutual exchange of salts the formation of scales is avoided, incrustation
prevented without any damage to the boilers, and scales already formed are
detached. Other foreign matter such as clay and dirt mechanically introduced by
the feed water becomes enveloped by the oxyhydrate of iron and is blown off
from the boiler when convenient, or otherwise removed from the same when not in
motion.
Having now described the nature and object of the said Invention, I wish it to
be understood that I claim as the Invention communicated to me from abroad by
the said Alfred Cords and August Deininger,―

page_text: The prevention or removal of incrustation in steam boilers by the addition to
the feed water of sulphate of iron as hereinbefore more particularly set forth and
described.
In witness whereof, I, the said George Davies, have hereunto set my hand
and seal, this Fifteenth day of October, in the year of our Lord One
thousand eight hundred and eighty.