A CONSTRUCTION OF LOW PRESSURE STEAM MOTOR and in what is to and
Year: 1885

page_text: I, HENRY DAVEY, of Headingley Leeds in the county of York Engineer, do
hereby declare the nature of my invention for "A CONSTRUCTION OF LOW PRESSURE
STEAM MOTOR and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
"
This invention relates to a low pressure steam boiler, engine and condenser,
specially suitable for electric lighting in private houses and for working domestic
machinery, where it is important to provide safety against explosions and to
require only a small amount of attention.
The boiler is self feeding in respect of fuel and water and is in the form of an
upright vessel having a central space for the fuel and an annular space for the
water surrounding the fuel space.
Communicating with the water space of the boiler there are two float chambers,
one having a float for regulating the supply of feed water, and the other a float for
regulating a damper in the chimney. The latter float chamber communicates by a
pipe with the lower part of the boiler and is open to the atmosphere. While the
pressure in the boiler is equal to that of the atmosphere the float is kept up, and
the damper which is connected to the float is closed or nearly so. When the
pressure in the boiler falls below that of the atmosphere, the water in the float
chamber being pressed into the boiler descends, and the float also descending opens
the damper. The float in the chamber for regulating the feed water supply in
descending opens a valve admitting water to the boiler. The fuel chamber has, at
its bottom, fire bars, on which the fire is lighted, the chamber being then filled up
with fuel which descends as that below burns away, fresh fuel being added from
time to time if desired. By this arrangement, the necessity for frequent stoking is
avoided, the fire burning for a considerable time without attention.
Connected with the boiler a low pressure engine is arranged to work with steam
at or below the atmospheric pressure. It has an inverted steam cylinder by
preference made of bronze or gun metal to avoid the necessity for lubrication.
This cylinder is enclosed in a steam jacket mounted on a framing, the base of
which constitutes a surface condenser consisting of a number of horizontal tubes
surrounded by water. The water space is connected by a pipe to the feed water
float chamber. There is also a pipe supplying cold water at the bottom, and a pipe
leading off hot water from the top. These pipes communicate respectively with

page_text: the lower and upper parts of a tank, so that when the engine is at work, the water
circulates through the condenser and the tank until the water becomes too much
heated for circulation.
The tubes of the surface condenser connect two end chambers from which an
air pump draws the water of condensation and such air as may accompany it,
discharging into the water space of the condenser or into the circulating tank. By
this arrangement, the same water may be used over and over again for steam, and,
as the cylinder of the engine requires no lubrication, no lubricant can get into the
boiler to interfere with its action. The pump might, however, if desired, discharge
into a drain.
Fig. 1 of the accompanying drawings is à longitudinal section partly in elevation
of a boiler and engine according to my invention, Fig. 2 is a transverse section of
the damper float chamber, and Fig. 3 is a section of the air pump. a is the fuel
chamber and b the water chamber of the boiler, c is the float for regulating the
damper, and d the pipe connecting the float chamber to the bottom of the boiler;
e is the float chamber for the feed water, and f the pipe connecting it with the
condenser chamber, g is the steam cylinder; and h the steam pipe connecting the
cylinder jacket with the boiler; i is the condenser chamber and the condenser ;
m is the exhaust pipe of the engine leading to the tubes of the condenser k; n is
the air pump which is attached to the side of the condenser chamber; o and p are
the circulating pipes communicating with the tank r.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1, The construction of a low pressure steam boiler, substantially as described
with reference to the drawing.
2, The combination of the said steam boiler with the floats and float chambers
and damper substantially as described and illustrated by the drawing.
3, The peculiar combination of the engine and condenser, substantially as
described with reference to the drawing.
4, The peculiar combination of steam engine, condenser and boiler, substantially
as described with reference to the drawing.
5, The peculiar combination of steam engine, condenser, boiler and circulating
tank, substantially as described with reference to the drawing.
Doted this 19th dow of February 1985
Doted this 19th day of Febr
of February 1885
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.