IMPROVEMENTS IN AND RELATING TO MARINE STEAM ENGINES OF THE COMPOUND TYPE
Year: 1882

page_text: LETTERS PATENT to George Rodger of Barrow in Furness in the County of
Lancaster Engineer-for an Invention of "IMPROVEMENTS IN AND RELATING
TO MARINE STEAM ENGINES OF THE COMPOUND TYPE."
"
PROVISIONAL SPECIFICATION left by the said George Rodger at the Office
of the Commissioners of Patents on the 23rd June 1882.
GEORGE RODGER, of Barrow in Furness, in the County of Lancaster, Engineer
IMPROVEMENTS IN AND RELATING TO MARINE STEAM ENGINES OF THE COMPOUND
TYPE"
My Invention relates to that class of compound engines for marine purposes
(having two cranks) in which the steam is used three times, namely first at high
pressure second at intermediate pressure and third at low pressure and consists
in certain arrangements of the steam cylinders for carrying out the said three
grades.
According to my Invention I use two high pressure cylinders, each of the
cylinders being placed respectively on the top of and in tandem combination with
an intermediate cylinder and a low pressure cylinder, thus one high pressure
cylinder is in tandem combination with the intermediate cylinder the piston thereof
being on the same rod and the other high pressure cylinder is in tandem combination
with the low pressure cylinder, the piston thereof likewise being on the same rod.
Both high pressure cylinders exhaust into the intermediate cylinder, which in turn
exhausts into the low pressure cylinder. The steam is thus first used in the high
pressure cylinders from which it is expanded into the intermediate cylinder from
which it is expanded into the low pressure cylinder. By this arrangement, I
obtain a compact engine with a greater certainty of starting in any position,
interchangeability of parts, case with which compound engines of the ordinary
type can be recompounded, so as to suit them for higher pressures, also general
simplicity.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Rodger in the Great Seal Patent Office on the 21st December
1882.
GEORGE RODGER, of Barrow-in-Furness in the County of Lancaster, Engineer
"IMPROVEMENTS IN AND RELATING TO MARINE STEAM ENGINES OF THE COMPOUND
TYPE."
My Invention relates to that class of compound engines for marine purposes,
(having two cranks, at right, or other suitable angles to each other on one shaft) in
which the steam is used three times, namely, first at high pressure, second at
intermediate, and third at low pressure and consists in certain arrangements of the
steam cylinders for carrying out the said three grades, and the following is a
description of my Invention in such full, clear, and exact terms, as will enable
anyone skilled in the art of constructing marine steam engines to put my Invention
into practice, reference being had to the three Sheets of Drawings making part of
this Specification and to the letters and figures of reference marked thereon like
letters and figures being used to denote like parts throughout the various views
By the Drawings there is represented the marine screw engines having two
cranks on one shaft (the steain being used three times) according to my Invention.
DESCRIPTION OF THE DRAWINGS
Figure 1 is a side elevation shown partly in section of the engines.
Figure 2 is an end view of Figure 1 partly in section.
Figure 3 is a sectional plan taken at X X Figure 1.
Upon reference it will be seen that according to my Invention I use two high
pressure cylinders A A' arranged, as shown in the Drawings namely each of the
cylinders A A' are placed respectively on the top of and in tandem combination
with an intermediate cylinder B and a low pressure cylinder C, thus the high
pressure cylinder A is in tandem combination with the intermediate cylinder B
and the piston A of the high pressure cylinder A is on, or in connection with the
same piston rod D which serves as the piston rod of the intermediate cylinder B.
In like manner the other high pressure cylinder A' is in tandem combination with
the low pressure cylinder C and the piston A³ of the high pressure cylinder A' is
on, or in connection with the same piston rod E, which serves as the piston rod of
the low pressure cylinder C. The piston rods D E through the connecting
rods FG work the two cranks H H¹ which are placed at right angles to each other
on the same connected shaft K as shown in the Drawings. High pressure steam
is admitted from the steam pipe J through the valves LL to the high pressure
cylinders A A¹ and after such steam has been used in the high pressure
cylinders A A¹ it is exhausted therefrom into the pipe M (which is common to
both cylinders A A') and through the valve N into the intermediate cylinder B.
After use in the intermediate cylinder B, the steam is exhausted through the
passages B B and through the valve P into the low pressure cylinder C. For
the arrangement of passages B' B' see Figure 3.
The steam is thus first used in the high pressure cylinders A A¹ from which it
is expanded into the intermediate cylinder B from which it is expanded into the
low pressure cylinder C, so as to cause the piston rods D E through the connecting
rods F G to work the two cranks H H on the same connected shaft K. By this
arrangement 1 obtain a compact well balanced construction of engines with a great
certainty of starting in any position, interchangeability of parts and ease by which

page_text: compound engines of the ordinary four cylinder tandem type can be recompounded,
so as to suit them for higher pressures. Also great general simplicity.
Having thus particularly described my Invention and shown a means of carrying
the same into practice, what I claim as the Invention secured to me by the
hereinbefore in part recited Letters Patent is:
The particular combined arrangement of of triple expansionm arino screw steam
engines constructed as herein described and as shown in the Drawings hereto
annexed,
In witness whereof, I the said George Rodger have hereunto set my hand
and seal this Fifteenth day of December in the year of our Lord One
thousand eight hundred and eighty two.
GEORGE (L.S.) RODGER.