Improved Feed-water Heater for Steam Boilers.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improved Feed-water Heater for Steam Boilers.
I, WALLACE FAIRWEATHER, C.E., of 62, Saint Vincent Street, in the City of
Glasgow, Chartered Patent Agent, do hereby declare the nature of this invention,
(as communicated to me by Carl August Lindvall, Chief Engineer, of 186 B,
Hornsgatan, Stockholm, Sweden, to be as follows:-
It is a well known fact that in generating steam, the economy is increased by
feeding the boiler with hot water. It is also well known that when a boiler is fed
with cold water, the evaporation ceases wherever the cold water enters, and, as far
as it extends at a temperature below the boiling point. The boiler, in that part,
only heats water and does not evaporate it. Since water absorbs heat much
faster when it evaporates than when its temperature is simply rising, it follows
that it is not economical to have any part of the water in the boiler mixed with
water of lower temperature.
The cold water also causes the parts of the boiler with which it comes in con-
tact to expand less than the other parts, thus bringing about unequal strains that
tend to break or destroy the boiler. For these reasons it is desirable to have the
feed-water heated nearly up to the temperature of the water in the boiler before it
mixes with the same.
This Invention pertains to a feed-water heater of the kind placed in the steam-
room of the boiler, consisting of a hood or box placed above the water-line in the
boiler and on the inside provided with shelves.
Its upper part communicates with the feed-water pipe and is provided with a
spreading disc or cone, that causes the water to spread out in a thin sheet all round
to the said shelves. The said hood or box is open only at its bottom and inside the
same is placed another smaller hood or box provided on the outside (towards the
outer hood) with shelves in such a manner that the feed-water is poured alternately
on the shelves of the said outer and inner hoods.
The working of the apparatus is as follows:-
The feed-water entering the apparatus from the feed-water pipe meets the said
spreading disc or cone and is distributed around the nearest upper shelf, e.g., of
the outer series. From that shelf the water runs on to the next lower shelf of the
under series, from here to the next lower of the first. mentioned series and so on
from the shelf of one hood to the next lower shelf on the other hood. As soon as
the water enters the apparatus, it condenses the steam met with, absorbing its
latent heat, causing a rush of steam from below to pass up between the rows of
shelves. In as much as the steam on its way upward has to break through the
stream of water once between each row of shelves, the water cannot avoid being
heated to a temperature near that of the live steam, before the feed-water reaches
the water surface of the boiler.
This feed-water heater is cheap, requires no special space in the engine room, is
easily applied to new or old boilers, requires no adjustment and heats the feed-
water (even the donkeyfeed) nearly to the temperature of the steam in the boiler.

page_text: When used for locomotive-boilers, or the like, where the steam-space is too
small, the apparatus may be placed in a special dome provided for that purpose.
The disc or cone above mentioned, that spreads the water, may be made to close
the opening of the inlet-pipe by means of spring-pressure or the like so that it
will only open when the feed-water presses it open.
Dated this 1st day of September, 1896.
Improved Feed-water Heater for Steam Boilers.
I, WALLACE FAIRWEATHER, C.E.,. of Saint. Vincent Street, in the City of
Glasgow, Chartered Patent Agent, do hereby declare the nature of this invention,
and in what manner the same is to be performed, (as communicated to me by
Carl August Lindvall, Chief Engineer, of 186 13, Hornsgatan, Stockholm,
Sweden), to be particularly described and ascertained in and by the following
statement:-
It is a well known fact, that in generating steam, the economy is increased by
feeding the boiler with hot water. It is also well known, that when a boiler is
fed with cold water, the evaporation ceases wherever the cold water enters, and as
far as it extends at a temperature below the. boiling point. The boiler in that part
only heats water and does not evaporate it. Since water absorbs heat much faster
when it evaporates than when its temperature is simply rising, it follows. that it
is not economical to have any part of lower temperature. The cold water also
causes the parts of the boiler, with which it comes in contact, to expand less than
the other parts, thus bringing about unequal strains that tend to break or destroy
the boiler.
For these reasons it is desirable to have the feed-water heated nearly up to the
temperature of the water in the boiler before it mixes with the same.
This invention pertains to a feed-water heater of the kind placed in the steam-
room of the boiler, which heats the feed-water (even the donkeyfeed) nearly to the
temperature of the steam in the boiler, before it mixes with the water, thus making
it possible to have all parts of the boiler working to the highest effect in evapora-
ting water.
The invention is illustrated in the accompanying drawing, in which Fig. 1 shows
a vertical section of such a feed-water heater; Fig. 2 shown a horizontal section of
the same; Fig. 3 shows the application of the heater to a marine boiler and Figs. 4
and 5 show how the heater may be inserted in a locomotive boiler or the like.
Referring to the drawing, A represents a hood or box placed above the water-
line in the boiler, and on the inside provided with shelves B B. Its upper part
communicates with the feed-waterpipe and is preferably provided with a spreading
disc or cone C that causes the water to spread out in a thin sheet all around to the
said shelves. The said hood or box is open only at the bottom and inside the same
is placed and held in a suitable manner another smaller hood or box D provided
on the outside (towards the outer hood) with shelves E E, placed near to and pre-
ferably alternating with the said shelves B B, in such a manner, that the feed-
water is poured alternately on the shelves of the said outer and inner hoods.
The spreading disc or cone C may be either fixed or, preferably, loose and
pressed upwards by a spring F or the like, for instance, as shown in the drawing.
The working of the apparatus is as follows:-The feed-water entering the
apparatus from the feed-waterpipe meets the said spreading disc or cone, and is
evenly distributed around the nearest upper shelf of the outer series. From that

page_text: shelf the water runs unto the next lower shelf of the inner series, from here to the
next lower of the first mentioned series, and so on from the shelf of one hood to
the next lower shelf of the other hood.
As soon as the water enters the apparatus, it condenses the steam met with
absorbing its latent heat, causing a continual rush of steam from below to pass up
between the rows of shelves. In as much as the steam, on its way upward, has to
break through the descending stream of water once between each row of shelves,
the water cannot avoid being heated to a temperature near that of the live steam
before the feedwater reaches the watersurface of the boiler.
When used for locomotive or torpedo boat boilers, or the like, where the steam-
space is small, the heater may be placed in a special small dome provided for
that purpose, as shown in Figs. 4 and 5.
This feed-water heater is cheap, requires no special space in the engine-room,
is easily applied to new or old boilers and requires no adjustment.
Having now particularly described and ascertained the nature of this said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. In a feed-water heater for boilers a bottomless but otherwise closed box or
hood, placed inside the boiler above the waterline and connected to the fed-water
pipe and on the inside provided with a series of shelves, an inner similar box or
hood, having its shelves on the outside near to the said shelves of the outer hood,
and a spreading disc or cone below the inlet of the feed-water and above the said
inner hood, substantially as and for the purpose set forth.
2. In a feed-water heater for boilers, the combination with the teed-water pipe
of a bottomless box or hood placed in the boiler above the water line with its
upper end connected to the water pipe, and on the inside provided with a series
of shelves, and an inner hood provided with a similar series of shelves on the out-
side towards and near the shelves on said outer hood, substantially as and for the
purpose set forth.
Dated this 25th day of May 1897.