An Improvement in Compound Steam Engines.
Year: 1891

page_text: Date of Application, 22nd Aug., 1891
Complete Specification Left, 20th May, 1892-Accepted, 9th July, 1892
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PROVISIONAL SPECIFICATION.
An Improvement in Compound Steam Engines.
I, FREDERICK WILLIAM STOKER Mechanical Engineer, of Erith Iron Works,
Erith in the County of Kent, do hereby declare the nature of this invention to be
as follows:-
My invention relates to a construction and arrangement of the cylinders, ports
and slide valves of a compound steam engine such that the strain conveyed from
the pistons to the crank is always in one direction and also the strain conveyed
from the eccentric to the slide valve, the knocking resulting from loose joints of
these connections being thus avoided however high may be the speed of the
engine.
I place the high pressure cylinder in line with and above the low pressure
cylinder connecting the pistons rigidly together. At the side I arrange a slide
case in which works a double ported D slide valve governing the ports leading to
the top and bottom of the low pressure cylinder and an exhaust port between them.
This slide case is always in communication through a port with the bottom of the
high pressure cylinder. Above the D slide valve and connected to it by a rod is
a piston valve in a cylindrical casing which is supplied at the top with the high
pressure steam and has a lateral port to the top of the high pressure cylinder.
The engine works as follows:-The high pressure steam which always presses on
the piston valve and so maintains the strain on the eccentric always in one direction,
acts first in the cylinder above the high pressure piston pressing it down. It then
passes under the high pressure piston putting it in balance. The exhaust steam
passes from the lower end of the high pressure cylinder into the low pressure
cylinder and presses its piston down at the same time that fresh high pressure
steam is pressing down the high pressure piston. The steam from above the low
pressure piston is led below the piston putting it in balance as it ascends and then
escapes as exhaust. A second pair or several successive pairs of cylinders arranged
in the same manner may be combined each pair acting independently of the others,
or each pair supplying the next pair with its exhaust so as to act as compound.
Although I have described the cylinders as being arranged vertically with the
high pressure cylinder uppermost, they may obviously be arranged horizontally or
inclined or inverted.
Dated this 22nd day of August 1891.
ABEL & IMKAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improvement in Compound Steam Engines.
I, FREDERICK WILLIAM STOKER, Mechanical Engineer, of Erith Iron Works,
Erith in the County of Kent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
My invention relates to a construction and arrangement of the cylinders, ports
and slide valve of a compound steam engine, such that the strain conveyed from.
the pistons to the crank is always in one direction and also the strain conveyed
from the eccentric to the slide valve, the knocking resulting from loose joints of
these connections being thus avoided, however high may be the speed of the
engine.

page_text: As shewn in the accompanying drawings by vertical section Fig. 1 and sectional
plan Fig. 2, I place the high pressure cylinder H in line with and above the low
pressure cylinder I connecting their pistons rigidly together. At the side I
arrange a slide case in which works a double ported D slide valve D governing
the ports leading to the top and bottom of the low pressure cylinder L and an
exhaust port. E between them. This slide case is always in communication through
a port P with the bottom of the high pressure cylinder H. Above the slide valve D
and connected to it by a rod is a piston valve V in a cylindrical casing which is
supplied by a pipe S at the top with the high pressure steam, and has a lateral
port to the top of the high pressure cylinder H. The engine works as
follows:-
The high pressure steam, which always presses on the piston valve V and so
maintains the strain on the eccentric which works the slide valve always in one
direction, acts first in the cylinder H above the high pressure piston, pressing it
down. The slide valve then rising, the steam passes by the ports Q and P under
the high pressure piston putting it in balance. The slide valve then descending the
exhaust passes from the lower end of the high pressure cylinder by the port P into
the low pressure cylinder and presses its piston down, at the same time that fresh
high pressure steam is entering by the port Q and pressing down the high pressure
piston. The steam from above the low pressure piston is led through the slide
valve D below the piston, putting it in balance as it ascends and then escapes as
exhaust by the port and passage E. A second pair or several successive pairs of
cylinders arranged in the same manner may be combined each pair acting indepen-
dently of the others.
Although I have described the cylinders as being arranged vertically with the
high pressure cylinder uppermost, they may obviously be arranged horizontally or
inclined or inverted.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A compound steam engine having its high and low pressure cylinders arranged
in line with their pistons rigidly connected, the cylinders being provided with a
slide valve and a piston valve which are always pressed in the one direction and
which govern ports whereby the steam is admitted to the cylinders so as always to
deliver its working pressure on the pistons in the one direction, substantially as and
for the purpose herein set forth.
Dated this 20th day of May 1905
ABEL & IMRAY,
Agents for the Applicant.