Year: 1886

page_text: Date of Application, 24th Nov., 1886
Complete Left, 23rd Sept., 1887
Complete Accepted, 25th Oct., 1887
I JOHN TWEEDY, of Newcastle-on-Tyne, in the County of Northumberland, a
member of the firm of Wigham Richardson & Co., Shipbuilders and Engineers, do
hereby declare the nature of this invention to be as follows:-
My invention has reference to the general arrangement of parts of marine engines in
which it is required to expand the steam through four successive stages-According
thereto in the case of an engine of small or medium size, four cylinders are employed
in conjunction with a four throw crank shaft each cylinder being connected directly to
one of the four cranks.
In the case of a larger engine having two low pressure cylinders five cylinders are
used in conjunction with a four throw crank shaft and one of the cylinders is placed
tandem wise over one of the other cylinders.
By the described arrangements the cylinders and their adjuncts are rendered more
accessible, the strains on the shafting are reduced, the turning thereof is rendered
more uniform, and at the same time greater facility in starting and disconnection of
engines in case of accident is attained than in four stage compound engines as
heretofore constructed.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.

page_text: Improvements in Compound Marine Steam Engines.
I, JOHN TWEEDY, of Newcastle-on-Tyne, in the county of Northumberland, a
member of the firm of Wigham, Richardson & Co., Ship-builders and Engineers, 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:
My invention has reference to the arrangement of compound marine steam engines
wherein steam is expanded in four stages in such a manner as not only to render the
parts readily accessible but also to subject the shaft through which the resulting power
is transmitted to less stress and to render the strain more uniform than has heretofore
been usual with engines in which there has been quadruple expansion.
To this end, in the case of an engine of small or medium size, four cylinders are
employed in conjunction with a four throw crank shaft, each cylinder being connected
directly to one of the four cranks.
In the case of a larger engine having two low pressure cylinders, five cylinders are
used in conjunction with a four throw crank shaft, and one of the cylinders is placed
tandem-wise over one of the other cylinders.
Referring to the annexed drawings:
Fig. 1 is a front elevation,
Fig. 2 a plan, and
-
Fig. 3 an end elevation of so much as is necessary to the understanding of my
invention of a typical example of inverted cylinder quadruple expansion marine
engine constructed in accordance therewith. In this arrangement I use four
cylinders A, B, C, and D, but instead of placing them in groups over a two throw
crank shaft as heretofore has been usual, I place them all in or almost in the same
horizontal plane as shown by the figures, so that the valves, covers, pistons, and other
details are more accessible than heretofore.
Of the four cylinders, A is the smallest or high pressure cylinder which receives its
steam direct from the boilers through the pipe 1, the ingress and egress being con-
trolled by a valve working in the steam chest J. After working in this cylinder, the
steam is conveyed through the pipe 2 to the steam chest K of the second stage
cylinder B, the chest K being also provided with a controlling valve. From this
cylinder B, the steam is conveyed to the third stage cylinder C by the pipe 3 and
thence on through the pipe 4 to the last stage or low pressure cylinder D, suitable
valves being provided in the chests L and M. From the last stage cylinder D the
steam is conveyed to a condenser P which may be of ordinary kind, where it is con-
densed and afterwards returned to the boiler again in the usual way. I connect the
cylinder A to the crank E, the cylinder B to the crank F, the cylinder C to the crank G,
and the cylinder D to the crank H, by pistons and connecting rods so that each
cylinder works on its own crank.

page_text: The four cranks when made separate are bolted or otherwise fastened securely
together and form when so fastened what may be termed a four throw crank shaft, the
strains on and turning of which and of the propeller and parts attached to it, are (with
cylinders proportioned to produce the most efficient expansion of the steam) more
uniform than in existing engines in which the cylinders are proportioned to produce
the most efficient expansion of the steam through four stages.
Figs. 6, 7, and 8 illustrate a modification suitable for engines of larger size in which
it is necessary to have two low pressure cylinders. According to this modification,
five steam cylinders are used, and in one arrangement of this modification I place one
of the cylinders-for example the cylinder A-over one of the other cylinders-for
example the cylinder D-In another arrangement of the same modification, one of the
two low pressure cylinders D¹ is made smaller than the other, and the high pressure
cylinder A is placed over it, so that, with less range of temperature, the power
developed by the two cylinders, acting together on the same crank pin, is more nearly
uniform than that of the three remaining cylinders.
Engines with horizontal or diagonal cylinders may be constructed according to my
invention combining four or five steam cylinders to operate with four stages of expan-
sion on a four throw crank shaft, and in such cases the framing, pumps, valves, and
gear are modified in relation to the cylinders in a manner usual with horizontal and
diagonal marine engines.
Fig. 4 is an elevation and
Fig. 5 a plan of a horizontal engine constructed in accordance with my invention.
In carrying out my invention the details of the crank shafts and valve gear, as well
as the position of the valves, may be varied according to the requirements of each
particular case; as, for example, I have shown in Fig. 2, two of the valves L and M
at the sides of the cylinders, and two J and K in the lines of and vertically above the
crank shaft, which arrangements apply equally to other modifications of the engines.
Another arrangement of the valves is shown in Fig. 7, where all the valves
J, K, L, M, and Mare placed at the sides of the cylinders.. This arrangement is
equally applicable to other modifications of the engines.
Having now particularly described and ascertained the nature of the said invention,
and in what manner it is to be performed, I declare that what I claim is :-
1. A quadruple expansion marine steam engine comprising four cylinders with
pistons and four connected cranks, the arrangement being such that the steam does
duty in all and is expanded in each of the cylinders successively, and the power from
each is transmitted through a different crank of the four, as above set forth.
2. A compound marine steam engine comprising five cylinders and four connected
cranks, the construction and arrangement being such that the five cylinders work with
four stages of expansion and the power is transmitted through the four cranks,
substantially in the manner hereinabove described.
3. A quadruple expansion marine steam engine comprising four connected cranks
and five cylinders, one of which, a high pressure cylinder, is placed tandem-wise over
a low pressure cylinder smaller than the other low pressure cylinder, substantially as
described.
Deted this gond dass of Sentember 1887