A Process for Treating Chemically Softened Water so as to Prevent the Formation of an Adherent Deposit in the Feed Apparatus of Steam Boilers.
Year: 1891

page_text: Date of Application, 19th Feb., 1891
Complete Specification Left. 18th Nov., 1891-Accepted, 19th Dec., 1891
PROVISIONAL SPECIFICATION.
A Process for Treating Chemically Softened Water so as to Prevent
the Formation of an Adherent Deposit in the Feed Apparatus of
Steam Boilers.
We, LEONARD ARCHBUTT of 11 Charnwood Street, Derby, Analytical Chemist,
and RICHARD MOUNTFORD DEELEY of 10 Charnwood Street, Derby, Engineer,
do hereby declare the nature of this invention to be as follows:-
Water which has been softened by the use of lime, sodium carbonate, caustic
soda, &c., still retains in solution small and variable amounts of calcium and
When
magnesium carbonates which the softening process has failed to remove.
the softened water becomes raised in temperature in the hot injectors, pipes, &c.,
leading to steam boilers, a part of these dissolved carbonates is precipitated in the
form of an adherent soft deposit, which gradually chokes the pipes and clacks,
necessitating periodical cleaning.
Our process for preventing the formation of this deposit consists in impregnating
the softened water with the products of combustion of carbonaceous fuel, whereby
the alkaline earthy carbonates are retained in solution until the softened water has
passed into the boiler.
Dated this 19th dox of February 1891
LEONARD ARCHBUTT.
R. M. DEELEY.
COMPLETE SPECIFICATION.
A Process for Treating Chemically Softened Water so as to Prevent
the Formation of an Adherent Deposit in the Feed Apparatus of
Steam Boilers.
We, LEONARD ARCHBUTT, of 11 Charnwood Street, Derby, Analytical
Chemist, and RICHARD MOUNTFORD DEELEY, of 10 Charnwood Street, Derby,
Engineer, 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 :-
Water which has been softened by the use of lime, sodium carbonate, caustic
soda, &c., still retains in solution small and variable amounts of calcium and
The
magnesium carbonates which the softening process has failed to remove.
water may also contain small quantities of the same compounds in the state of
suspension owing to imperfect clarification after softening. When the softened
water becomes raised in temperature in the hot injectors pipes &c. leading to steam
boilers, a part of these dissolved carbonates is precipitated, and this, together with
any solid particles already in suspension, gradually forms an adherent soft deposit
on the interior of the pipes, clack boxes, &c., which has to be periodically cleaned
off to keep the apparatus in proper working order. This is a serious drawback to
the use of such water in locomotive boilers especially.
Our process for preventing the formation of this deposit consists in impregnating
the softened water with the products of combustion of carbonaceous fuel, whereby
the alkaline earthy carbonates are retained in solution until the softened water has
passed into the boiler. We interpose between the softening tank and the pump a
siphon pipe the upper end of which is elevated a few feet above high water level
in the tank. Entering the bend at the top of the siphon pipe we fix a small pipe
communicating with a chimney stack. The water drawn by the pump out of the

page_text: softening tank, in passing over the bend of the siphon, is thus made to aspirate and
mingle with combustion gases from the chimney. The water and gas then pass
together through the cylinder of the pump to a small storage tank from which the
boilers are supplied; the storage tank being open, allows the unabsorbed gases to
escape into the air. When the treatment of the softened water by this process is
commenced, the deposit in the feed-pipes and clacks ceases to form, and the interior
of the feed apparatus having been freed from the old deposit, afterwards remains
perfectly clean. As the smoke in the chimney gases causes some difficulty, we
generally substitute the products of combustion from a Bunsen gas burner for the
chimney gases, with equally good results so far as the prevention of the deposit is
concerned. For a large plant, we prefer, for economical reasons, to use the smoke-
less combustion gases from a coke stove of suitable form; and instead of allowing
the water and gases to pass through the same cylinder, we attach to the pumping
engine an additional cylinder for forcing the gases into the main conveying the
softened water from the pump to the storage tank. With some arrangements of
softening plant it may be preferable to force the combustion gases through
perforated pipes laid at the bottom of the storage tank and any other suitable
means may be adopted for bringing the softened water and the combustion gases
into intimate contact, provided always, that the impregnation takes place after the
softening process is completed. We add to the water enough carbonic acid to
convert all the dissolved carbonates into bicarbonates, and we prefer to use a slight
We introduce 10 cubic centimetres of the
excess controlled by the following test.
uncarbonated softened water into a graduated test mixer, and colour the water with
a few drops of a solution of phenolphthalein; we then add carbonated softened
water, 10 cubic centimetres at a time, until the pink colour is completely bleached.
From 90 to 100 cubic centimetres should be required to bleach the pink colour.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that
what we claim is :-
The process of treating chemically softened water by impregnating it with the
products of the combustion of carbonaceous fuel substantially as described.
Dated this Tenth day of November 1891.
LEONARD ARCHBUTT.
R. M. DEELEY.