Year: 1887

page_text: I ALFRED VINCENT NEWTON of the Office for Patents 6 Breams Buildings, Chancery
Lane in the County of Middlesex, Mechanical Draughtsman 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 :-
The nature of this invention, and the manner of carrying the same into effect, is
described by my foreign correspondent as follows:-
The object of this invention is to realize more fully than has been heretofore
accomplished, all the advantages to be obtained by the compound system of using
steam for motive power, and to obtain in a two cylinder compound engine, and by
double expansion, all the advantage sought for by the addition of a third cylinder or
even of a fourth, involving a triple or quadruple expansion, and to secure such
advantage, viz., the employment of steam at the highest initial pressure, and the
expansion of such steam to a degree beyond which there would be no economy with-
out the complex mechanism, and without the multiplicity of passages and ducts, and
consequent loss of heat, involved in the triple and quadruple systems of expansion.
In carrying out this invention, the two cylinders which I employ are both double
acting, and are arranged end to end, and their pistons are upon, or connected with one
and the same rod.-I construct the larger or low pressure cylinder with a calibre of
about nine, ten, or more times the area of that of the smaller or high pressure cylinder, and
I arrange the valves, and valve gear of the latter to cut off the admission of steam
thereto at about from one fourth to one fifth of the stroke of its piston.--I therefore
use the steam in the smaller or high pressure cylinder with a higher rate of expansion
than is customary in compound engines, and in fact, with as high a rate as, according
to the best practice, is economical in a single cylinder engine, and afterwards expand
it nine, ten, or more times in the larger or low pressure cylinder, and I thus obtain an
expansion of the steam to about from thirty six to fifty times its original volume, by
which high rate of expansion I am enabled to use steam at the highest initial pressure
that any boiler or generator could be made to carry, and to obtain all the advantage
of the expansion of such steam to the lowest tension which it would be economical to
maintain in the condenser.
It is in the two-cylinder compound steam engine organized as hereinabove stated
for using steam with so high a rate of expansion, that my invention consists,

page_text: irrespectively of the particular system of valves and valve gear employed for the
induction of the steam to and from the two cylinders, and its eduction from the larger
cylinder to the condenser.
Fig. 1 in the accompanying drawing represents a longitudinal central section of the
principal parts of a horizontal steam engine illustrating my invention, the framing,
the valve gear, the air pumps and other parts not necessary to illustrate the invention,
being omitted.
Fig. 2 is a central longitudinal section, on a larger scale than Fig. 1, of the cylinders,
pistons, piston-rods, condenser, and valves.
Similar letters of reference designate corresponding parts in both Figures.
A designates the smaller or high pressure cylinder, and A' the larger or low pressure
cylinder, arranged end to end, the larger one having a diameter of about three times
that of the smaller one.-B B¹ designate the two pistons fitted to the two cylinders
respectively, and both fast on the same rod, C, which passes through a stuffing box D
between the two cylinders, and through a stuffing box E at the outer end of the larger
or low pressure cylinder. F designates the condenser.
The cylinder A is represented in Fig. 2 as fitted with two valves ab at one end,
and with two other valves a* 6* at the other end, the valves a a* being for the
induction of the steam to the said cylinder from the boiler, and for cutting it off from
said cylinder at the proper point in the stroke, say at from one quarter to one fifth,
and the valves b 6* being for the eduction of the steam from the said cylinder, and its
induction to the larger or low-pressure cylinder A' through ducts c c*, which form
communications between the opposite ends of the two cylinders, that is to say, the
ducte forming communication between the left hand end of the high pressure cylinder
and the right hand end of the low pressure cylinder, and the duct c* forming com-
munication between the right hand end of the high-pressure and the left hand end of
the low pressure cylinders.
The low pressure cylinder is represented as furnished at its ends respectively with
eduction valves d d* for opening and closing connection between it and the condenser.
I have not thought it necessary to represent the valve gear for operating the
valves a a* b b and d d*, as valve gear of any well known kind may be used for
the purpose; the valve gear for operating the valves a a* being such as will open the
proper one at the commencement of each stroke of the piston and close it at that point
in the stroke at which the steam is to be cut off, to obtain, during the remainder of
the stroke, the high rate of expansion which is used in said cylinder in carrying out
my invention, and the valve gear for working the valves b b* and d d* respectively
being such as to make at proper times, and maintain, the free opening between the
two cylinders, and between the larger cylinder and the condenser, to afford freedom
for the continued high rate of expansion which I provide for by the great difference
of calibre of the two cylinders.
Having now particularly described and ascertained the nature of the said Invention
and in what manner the same is to be performed as communicated to me by my
Foreign Correspondent, I declare that what I claim is :-
A double-acting two-cylinder compound steam engine organized substantially as
herein described, whereby steam may be used at the highest practicable initial pressure,
and with a high rate of expansion in the smaller or high pressure cylinder, and after-
wards may be expanded in the larger or low pressure cylinder to the lowest tension
which it would be economical to maintain in the condenser.
Date : 711 1
T