Improvements in Safety Steam Generators.
Year: 1889

page_text: Date of Apolication, 22nd Oct., 1889-Accepted, 23rd Nov., 1889
COMPLETE SPECIFICATION.
Improvements in Safety Steam Generators.
1, SAMUEL WARWICK LUDLOW, of Madisonville, Hamilton County, Ohio, United
States of America, Civil Engineer, do hereby declare the nature of my invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
My invention relates to steam generators and has for its object an improved
construction whereby greater safety is assured than in ordinarily constructed steam
generators.
In the practical operation of steam generators the largest percentage of explosions
which occur are traceable to low water, or the absence of water which causes the
metal to be excessively heated. The frequent overheating of the metal operates upon
its fibre reducing its tensile strength and rendering it liable to rupture under a very
slight excess of pressure, or the introduction of cold water upon the overheated!
surface when it is suddenly flashed into steam or gas.
Practice has also demonstrated that boilers whose outer surface is exposed to the
direct action of the products of combustion in a furnace and from which a motor fluid
is drawn are frequently coated with calcareous matter which prevents the water in the
boiler from coming in contact with the inner surface thereof, and causes an effect
similar to the absence of water. Again, the calcareous deposit or incrustation
frequently becomes disengaged from the metal suddenly exposing it to the action of
tho pressure within or the cold water and results in bulging the metal if not in an
absolute rupture of the same.
The first named cause of explosion namely, low water is due largely to the fact that
comparatively few skilled engineers are employed for running or operating sinall
boilers and that persons employed in this capacity are frequently required to perform
other duties which necessitates their absence from the boiler, and from this cause
their attention is diverted the water in the boiler falls below the line, established for
safety and the metal becomes burned. The second cause is due to the deposit of mud
and calcareous matter in the water which is constantly pumped into the boiler to
supply it, coating the inner surface of the shell and the fire tubes.
By my invention both of these causes are removed, and a boiler or steam generator
produced which is absolute proof against injury to the fibre of the metal by over-
heating, and in which incrustation cannot occur.
The invention will be hereinafter described and particularly pointed out in the
claims.
In the accompanying drawings, which form part of this specification.
Figure 1, represents a vertical longitudinal section of a steam generator embodying
my invention.
Figure 2, a vertical cross section and end view thereof. Reference being had to
he drawings and the letters thereon. A, indicates an outer vessel which is provided
with a series of horizontal fire tubes or flues a, which communicate with the uptake in
he smoke stack. The vessel A, is filled with water to about, the line indicated at b,
hrough an aperture c, and is then hermetically sealed by a plug d.
Within the vessel A, is a steam generator B, which is provided with a series
f flues e. I make this steam generator preferably symmetrical with the outside vessel,
with the flues of the outside vessel passing within and through the flues of the
enerator, the water in the outside vessel thus forming a water jacket around the flues
f the steam generator as well as around its sides and ends. The steam generator is
uitably supported within the vessel A, so as to be enveloped by water and steam
when in operation, and is provided with a feed water pipe f, a safety valve C, a steam
apply pipe D, and the usual appurtenances of a steam generator such as a sight
auge etc. not shown.

page_text: Instead of the above construction with the fire flues of the hermetically sealed
vessel, arranged within the flues of the steam generator, these fire flues may also be
arranged underneath the steam generator, or other changes in the arrangement of
flues may be made without departing from my invention, which consists in surround-
ing the steam generator by a hermetically sealed vessel containing vaporizable liquid
so as to prevent the fire from acting directly on the external surface of the steam
generator.
Any liquid which will vaporize and conduct the heat of the products of combustion
to the steam generator B, may be used in the outer vessel A.
By the construction shown the water in the vessel A is used as a medium to
conduct the heat of the products of combustion to the water in the steam generator, is
vaporized and surrounds the upper part thereof and the body of water is unchanged,
thereby reducing the possibility of the formation of any incrustation to the minimum.
The water for the outer vessel should be purified by filtration distillation or by
chemical treatment before being introduced to the vessel especially in large vessels.
The body of water being enclosed in a hermetically closed vessel, and used only as
a heat transmitting medium the water line cannot vary to any appreciable extent and
the danger due to exposing the metal to the products of combustion without being
properly covered with water on the inside, is entirely removed.
Having now particularly described and ascertained the nature of my invention.
and in what manner the same is to be performed, I declare that what I claim is :-
1. A steam generator within a hermetically sealed vessel, exposed to direct heat
and surrounded by a fluid in the hermetically sealed vessel through which the heat
is transmitted, substantially as described.
2. A steam generator consisting of an outer vessel hermetically sealed and contain-
ing a heat transmitting fluid, an inner vessel containing a vaporizable fluid and
surrounded by the fluid in the outer vessel, substantially as described.
3. A steam generator consisting of an outer vessel hermetically sealed, having a
series of fire tubes extending through the body thereof, an inner vessel provided
with flues and a vaporizable fluid in which the inner vessel is enveloped, substantially
as described.
4. A steam generator consisting of an outer vessel hermetically sealed and con-
taining vaporizable heat transmitting fluid and an inner vessel for generating
steam as a motor or other power enveloped by said fluid, substantially as described.
Dated this 22nd day of October 1889.
SAMUEL WARWICK LUDLOW.
Herbert & Co.,
18, Buckingham Street, Strand, W.C., Agents.
SAMUEL WARW.
Herbert & Co.,
LUDLOW.
18, Buckingham Street, Strand, W.C., Agents.