Year: 1886

page_text: We WILLIAM DYSON WANSBROUGH and RICHARD KENDALL EVANS, Engineers,
both of Nottingham in the county of Nottinghamshire do hereby declare the nature
of this invention to be as follows:-
This invention relates to an improved form of low pressure steam motor the
object being to produce a cheap and efficient motor for use where small power is
required. The motor is worked by the condensation of steam forming a vacuum
in the cylinder and may be arranged as follows: The boiler of cast iron or suit-
able material, is constructed preferably of a square or chest like-form, projections
being formed upon it to act as bearings for the crank shaft. The boiler contains an
internal furnace with a return flue arranged to be for the greater part of its length
below the working water level, the flue rises into the chimney through the steam
space and dome at the back of the cylinder so as to superheat the steam: For
feeding, and maintaining the water in the boiler at working level, we employ
preferably a copper float exhausted of air and enclosed in a suitable casing com-
municating with the water in the boiler; this float is connected to and actuates a
spherical valve automatically controlling the water supply, or any suitable device.
To prevent the pressure in the boiler rising above atmospheric pressure, we
provide one or more safety valves locked up, so that they cannot be loaded to a
greater pressure either by accident or design.
A cylinder of the ordinary construction used for steam engines is placed within
the steam space of the boiler, so as to be almost entirely surrounded by steam:
The piston and valve rods project through the boiler and suitable arrangements are
made to prevent leakage and wear of the gland packings. The piston rod is con-
nected by a connecting rod in the usual manner to the crank shaft, upon which a
fly-wheel is fixed. An ordinary governor is provided for regulating the speed of
the engine.
The exhaust steam enters à condenser which may consist of a thiu flat chamber
of copper or galvanised iron or suitable material, so arranged as to expose the
exhaust steam to the cooling influence of the atmosphere. The steam enters pre-
ferably at or near the top of the chamber, which is internally fitted with suitable
partitions by which the steam is caused to travel a considerable distance between
the cold surfaces of the sheets formning the condenser; a stream of water may be

page_text: caused to flow down the sheets if desired; or instead of the above described arrange-
ment a jet or surface condenser of usual type may be provided. An air pump of
ordinary construction is employed to pump out the water and air.
:
For automatically feeding the furnace a hopper or shoot of suitable form to
prevent jamming or bridging of the fuel, may be arranged fitted at or near its base
with an Archimedian screw worked by gearing or otherwise from the engine, for
the purpose of forcing fuel into the furnace at a regular and determined rate or
quantity per time. A centrifugal governor may be used in connection with the
automatic feeding apparatus to suspend the feeding when desired; or by an
alternative method of self firing arrangement, I may make use of an annular grate
revolving within a circular firebox, having a central "water leg." The grate is
slowly revolved by the engine and is fed at one point in the circumference by a
vertical hopper without a screw.

page_text: We WILLIAM DYSON WANSBROUGH and RICHARD KENDALL EVANS, Engineers,
both of Nottingham in the county of Nottinghamshire 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 :-
This invention relates to an improved form of low pressure steam motor, the
object being to produce a simple and cheap motor which shall perform its duty
with greater economy than heretofore, while requiring the least amount of super-
intendence and being least liable to break down and at the same time absolutely
safe from risk of explosion. The motor is worked by steam at or about atino-
spheric pressure.
The accompanying drawings clearly illustrate the form and construction of the
apparatus: Figure 1 is a longitudinal sectional elevation: Figure 2 is an end
part elevation with condenser in section: Figure 3 is a section on line ab figure 1.
Figure 4 is a detail of air pump and feeding device; Figures 5 and 6 are respec-
tively side and front elevations of an alternative form of surface. condenser;
Figure 7 is an elevation of an automatic firing arrangement; and Figure S is a
sectional elevation of an alternative arrangement for the same purpose. Similar
letters refer to similar parts in all of these figures.
The boiler A of cast iron or other suitable material is constructed preferably of a
rectangular or chest-like form as shown, having a steam dome formed at its back
end.
Within the boiler the furnace B is placed having its flue b returned and
arranged to be for the greater part of its length below the working water level so
as to economise heat as far as possible; the flue b passes up the chimney through
the dome at the back of the working cylinder which is placed horizontally
therein so as to be almost entirely surrounded by steam.
The cylinder is of the ordinary construction used for steam engines and is
provided with a slide valve of usual type which may be operated in the usual
manner. The piston and slide valve rods project through the shell of the boiler
and suitable arrangements are made to prevent leakage at and wear of the gland
packings. The piston rod is connected in the usual manner to the crank. upon the
shaft of which a fly wheel is keyed.
A governor D is provided which may be of the ordinary centrifugal type actua-
ting a valve d controlling admission of steam. to the slide valve. The exhaust
steam passes by pipe E upon which is placed the regulator valve e to a surface
condenser F provided with inlet and over flow pipes f f¹ respectively: The
tubes f3 of the condenser F are of. iron and their ends are formed screwed and
jagged and are, then tin coated and placed in position, and the tube plates f* f* are
cast upon them. This method enables a much larger number of tubes to be used
than if screwed or ferruled in the usual manner. The condenser F is placed close
to the boiler A and, rigidly connected thereto by lugs and bolts. Projections a a
may be formed on the boiler to act as bearings for the crank shaft, or they may be
formed upon the top of the condenser as shown in figures 1 and 2, or they may
take the form of bridges between the boiler and the condenser thus serving also for

page_text: the connection between the two. An air pump G of usual construction is provided
to pump out the condensed water and contained air, it is worked by a crank on the
crank shaft and delivers through pipe e¹ to the top part of condenser F.
Instead of the above described condenser, that shown in figures 5 and 6 may
be adopted consisting of a thin flat chamber F of copper, galvanised iron, or other
suitable material so arranged as to expose the exhaust steam to the cooling influence
of the atmosphere: The steam enters by pipe E preferably at or near the top of
the condenser as shown. The chamber F is fitted internally with partitions or
baffle plates g¹ g₁ by which the steam is caused to travel a considerable distance
between the cold surfaces of the side sheets of the condenser, and the condensation
may be assisted by causing a stream of water to trickle down these sheets if
desired.
For feeding and maintaining the water in the boiler at working level a copper
float H connected to an ordinary spherical equilibrium valve h is placed within the
boiler at working level: The valve his seated in the end of the delivery pipe J
leading from the top of the condenser F so as to get the hottest water for feeding;
as the water level falls float H descends, automatically opening valve h and
admitting water through J from F until working level is regained when his closed
and so maintained until the level of the water again falls. A sheet of glass ; may
be fitted if desired in the side of the boiler so that the level of the water will be
visible.
To prevent the pressure in the boiler rising above atmospheric pressure a safety
valve or pair of safety valves K is or are provided covered in and locked by cap k
so that it cannot be loaded to a greater pressure either by accident or design.
Figure 7 shows a method of automatically supplying fuel to the furnace. A
hopper or shoot of suitable form to prevent jamming or bridging of the fuel such as L
may be placed adjoining the fire door; at or near its base an archimedean screw M
is arranged which can be revolved by a worm and time gearing such as m driven
direct from the engine, and the screw M forces fuel at a regular and determined
rate or quantity per time into the furnace. A centrifugal governor may be used
in connection with the automatic feeding apparatus to suspend the feeding when
desired. Or by an alternative method an annular grate such as N figure 8 may be
provided revolving upon a central pivot or water-leg inside a circular fire box, and
fed by shoot similar to L at one point in its circumference: A screw such as M. is
not required in this case and the grate is timed by the gearing m driven by the
engine to revolve slowly.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed we declare that what
we claim is:
1. A low pressure motor constructed arranged and operating as hereinbefore
described and illustrated by figures 1, 2, 3 and 4 of the drawings.
2. A low pressure motor constructed arranged and operating as herein before
described and illustrated subject to the modification shown in figures 5 and 6.
3. The arrangements of low pressure motors herein before claimed in combination
with either of the forms of fuel feeding apparatus hereinbefore described and
illustrated.