IMPROVEMENTS IN APPARATUS FOR PURIFYING BOILER FEED WATER
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by John Clayton Mewburn at the
Office of the Commissioners 6f Patents, with his Petition, on the.
15th November 1872.-A communication from abroad by Monsieur
Farinaux, of Lille, France.
I, JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of
London, Patent Agent, and Consulting Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
PURIFYING BOILER FEED WATER," to be as follows :-
The object of the apparatus which forms the subject of this Invention
is to separate the calcareous or other salts from the water used for
feeding boilers before its introduction into these boilers.
To obtain the best result and to render it appliable to all kinds of
water a mechanical purifying apparatus should fulfil the following
conditions.
1st. To give to the water a high temperature obtained by superheated
steam or by a strong pressure of steam from the generator, and a long
contact with great alteration of surfaces between the steam, and the
water to be purified.

page_text: 2nd. A. sufficiently prolonged continuance of the water in the
apparatus.
None of the purifying apparatus heretofore employed have fulfilled
both these conditions, and consequently they have produced imperfect
results.
The improved apparatus which is intended particularly for water
charged with sulphate of lime and for sea water is constructed as
follows:-There is an upper vessel of cylindrical or other form, having at
its lower part a connection for introducing steam. It is fixed upon a
lower vessel which is conical at the bottom where it has a purging pipe
provided with a cock; this lower vessel communicates at its upper part
with the boilers so as to feed the water thereto. The upper vessel has a
cover which communicates with the feed
pump, Giffard injector, or other
source of supply. This cover has at its lower part a perforated plate. A
cone or cylinder open at each end rests on the upper edge of the lower
vessel, and extends some distance into the same. The upper vessel
contains a number of superposed discs of rather less diameter than the
vessel; they have each a number of slots or openings in them so
arranged that the slots or openings in one disc correspond with the full
parts of the discs immediately above and below. These discs are kept
at a short distance apart by washers.
The action is as follows:-The apparatus being situated above the
boilers to be fed is put in communication with the water supply, so that
the water enters and passes through the perforated plate which is
attached to the cover. The water thus falls in the state of drops or.rain
upon the series of slotted discs. In passing through the discs its descent
is impeded, owing to the slots in each disc being opposite full parts of the
next following disc, and as the upper vessel is in communication with
the steam of the boilers, this vessel is filled with steam at the same
pressure as that in the boilers. Thus the water in its impeded descent
rapidly acquires the high temperature of the steam. It has therefore
the same heat as the water in the boiler itself, and it is evident that the
heat which the steam imparts to the water is restored to the boiler which
it feeds. Thus there is no loss.
Now the temperature of the water in boilers working under a pressure
of five atmospheres is 305° Fahrenheit, and at this temperature all the
calcareous salts, sulphates of lime, and others, are precipitated in a
floculent state. The greater part of the deposits are therefore obtained

page_text: on the discs, and the remainder are precipitated into and through the
cone in the lower vessel, and can be evacuated from time to time by.
opening the cock every 4, 6, or 12 hours. The purifying vessel or
column should be high enough, especially for water containing sulphates
of lime, to contain a considerable number of the discs. There should
never be less than twenty, as it is upon their quantity that the length of
contact between the steam and water, and the slowness of the descent
depend, points indispensable for a good result.
Every week, fortnight, or month, according to the quality of the water
used, the cover should be removed and the discs cleaned. This may be
done by a brush or sponge. It may be effected without stopping the
working of the boiler by shutting off the several communications with
the purifying apparatus.
In order to impede the descent of the water, plates composed of rods
placed quincuncially may be used; but these would be more difficult to
cleanse than the discs above described. Or gratings, or bundles of wire,
or rings, or other suitable bodies may be placed in the apparatus to
impede the descent of the water in a divided state in a medium filled
with steam fresh from the boiler. This arrangement fully satisfies the
first of the conditions before enumerated, and is decidedly preferable to
successive epurations on flanged plates on which the water is heated only
in sheets, and therefore very imperfectly. With regard to the second
condition, the slow circulation of the water in the lower vessel assures it
a sufficiently long stay in the apparatus before its introduction into the
boilers.
In some cases I adopt for the purification of water according to the
principles above explained the mode employed for cooling waters of
condensation in refrigerators, in order to extract impurities from the
water by the high temperature acquired in a descent always impeded in
a vessel filled with fresh or superheated steam.