Improvements in Compound Steam Engines, Applicable also to other Steam Machines.
Year: 1889

page_text: Date of Application, 22nd July, 1889
Complete Specification Left, 21st Apr., 1890-Accepted, 24th May, 1890
PROVISIONAL SPECIFICATION.
Improvements in Compound Steam Engines, Applicable also to other
Steam Machines.
I, WILLIAM JAMES NORRIS of 3 Rutland Terrace, High Road, Leyton, in the
County of Essex, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the cylinders of that class of compound engine, actuated
by the pressure and expansive power of steam, in which both the high and low
pressure pistons are attached to the same piston rod, and are single acting as regards
the action of the steam when driving them, as in Patent No. 1582 of 1885 granted
to myself and Thomas Hosking, and has for its object the construction of these
cylinders in such a manner that they may be equally applicable to condensing or
non-condensing engines, that when either piston is not doing work, it shall then be
moving in equilibrium, that is to say with an equal pressure on both sides, and that
when working as a condensing engine the vacuum shall act on both pistons so that
the effective pressure of steam upon them is from zero minus a loss due to imperfect
vacuum only.
To attain these objects I employ but one valve and a particular arrangement of
ports, passages, and an exhaust chamber, whether for condensing or non-condensing
engines. The slide valve jacket is preferably cast with the high pressure cylinder,
this cylinder being provided with two steam ports only, and a passage from each
port to each end of the cylinder, one of which passages is continued to the corre-
sponding end of the low pressure cylinder, and at the other end of the low pressure
cylinder a passage is provided communicating with the exhaust chamber. The slide
valve is so arranged as to perform the threefold duty of admitting and cutting off
the steam in the high pressure cylinder, admitting steam from the high to the low
pressure cylinder, and exhausting both cylinders, the exhaust being effected through
the back of the slide valve, which has a port or ports through same and works
against a facing in the slide valve chest (preferably a seperate and adjustable casting)
having corresponding ports in same opening into the exhaust chamber, which
chamber is provided with a flange and opening for the exhaust pipe leading to the
condenser or to the atmosphere as may be desired.
1000
COMPLETE
SPECIFICATION.
Improvements in Compound Steam Engines, Applicable also to other
Steam Machines.
1, WILLIAM JAMES NORRIS of 3 Rutland Terrace, High Road Leyton, in the
County of Essex Engineer, 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 the cylinders of that class of compound engines actuated
by the pressure and expansive power of steam (or other gaseous fluid) in which
both the high and low pressure pistons are attached to the same piston rod, and are
single acting as regards the action of the steam when driving them, as in Patent
No. 1582 of 1885 granted to myself and Thomas Hosking, and has for its object the
construction of these cylinders in such a manner that they may be equally applicable
to condensing or non-condensing engines, that when either piston is not doing work
it shall then be moving in equilibrium that is to say, with an equal pressure on both

page_text: sides, and that when working as a condensing engine, the vacuum shall act on both
pistons so that the effective pressure of steam upon them is from zero minus a loss
due to imperfect vacuum only.
To attain these objects I construct the cylinder or cylinders in either of the
following manners, and as shewn in Figs. 1 & 2, Sheets 1 & 2. The complete
cylinder consists of the high and low pressure cylinders (either cast in one or bolted
together according to the practicability of casting them) which are placed in line
with each other so that both the high and low pressure pistons may be secured to
the same piston rod, and has one slide valve as shewn in the Figures, or any
suitable modification of the same, which valve serves both the high and low pressure
cylinders in the manner hereinafter described.
The small or high pressure portion of the cylinder has a steam port (3) and
passage (4) by which the steam from the boiler is admitted into this part of the
cylinder to actuate the high pressure piston, and a second port (5) and passage (6)
communicating with the other end of this portion of the cylinder, and also with
passage (7) leading to and into the corresponding end of the larger or low pressure
portion of the cylinder, that is, either above or below the pistons according to
whether the cylinder is arranged as shewn in Figs. 1 or 2, the actions of which are
respectively as hereinafter described. The cylinder is divided between the high and
low
pressure portions by a diaphragm (8) which in small engines may be cast with
the cylinder, and in larger engines may be a seperate casting as shewn in the Figs.
and bolted in.
The outer ends of both the high and low pressure portions are closed with covers
and jointed in the usual way, one of which covers is provided with a stuffing box
and gland for the piston rod to pass through, as it will be obvious that this stuffing
box inay be fitted equally as well to the low pressure as to the high pressure cover
in cases where the same may be desired, and it will also be obvious that a stuffing
box with suitable packing may be used in the diaphragm separating the high and
low pressure pistons, in place of the plain bush shewn in Figs. 1 & 2.
A steam chest or valve casing is cast on the cylinder as shewn having the steam
inlet (1) suitably placed, but in lieu of the ordinary door or cover, a casting (9) is
secured, having ports (10) single, double, or more, as may be most convenient,
through same, these ports forming the exhaust passage for exhausting the steam from
above both the high and low pressure pistons when arranged as in Fig. 1. and below
these pistons when arranged as in Fig. 2. the exhaust being effected through the
valve as hereinafter described, so that there is no exhaust port in the cylinder
face.
To this valve chest or casing an exhaust passage (11) is formed, which communi-
cates with passage (12) and port (13) into low pressure cylinder, and to this exhaust.
passage or chamber the exhaust pipe (14) is attached, which pipe is open to the
atmosphere in non-condensing engines, and communicates with the condenser in
condensing engines, and where two or more of these cylinders are placed side by
side, this exhaust chamber and exhaust or eduction pipe may be common to both or
all of the cylinders. The valve (15) which regulates the admission, cut off, and
exhaust, in the manner hereinafter described, is by preference of the form shewn in
the drawings, and practically a balanced slide valve, but any suitable modification of
same, such as piston valves, may be used. This valve can be actuated by an
eccentric in the ordinary manner, or by any other suitable valve motion, and
although not shewn in the drawings an expansion valve may also be employed when
a very early cut off is required.
It will be evident that various means, which do not require to be specified, may be
taken for adjusting plate (9) and the valve to each other, so as to keep the valve
steam tight, any arrangement for the ordinary relief plate being applicable.
The cylinder may be cast in the usual way, and in those of moderate and large
diameters it is preferable to cast them with a jacket (16) supplied with steam from
the steam pipe or valve casing, or with superheated steam or hot air where the same
.can be practically employed and where it is desirable for practical reasons, the

page_text: working barrels of the cylinders may be liners fitted therein, as is now in common
use, instead of being cast with the jackets as shewn in the drawings, and for
facilitating the casting of these cylinders, the two portions, that is the high and low
pressure, may be cast seperately and bolted together, but whenever practicable they
are by preference cast in one as shewn in Figs. 1 & 2.
In cylinders of small diameters the jackets may be dispensed with.
The action of this cylinder is as follows:-
The steam enters the valve casing (2) by the pipe or inlet (1), and is admitted into
the high pressure (i.e. the small) end by the port (3) and passage (4) to the underside
of the piston as in Fig. (1) or to the upper side of the piston as in Fig. (2) and is
cut off at any desired point of the stroke of the piston by the valve in the usual way.
As the stroke is completed, the travel of the valve opens the port (4) to the interior
space of the valve, and has closed the exhaust ports in plate (9) thus permitting the
steam to pass from above or below the high pressure piston as the case may be, by
port (5) and passage (6) to the other side of the high pressure piston, making tho
pressure on both sides of the piston the same, and also to the upper or underside of
the low pressure piston as the case may be, when the cylinder is arranged as in
Figs. 1 & 2 respectively, by passage (7) to do the work of the return stroke. The
port (5) is never covered, that is to say it is always open to the interior of the valve,
and the exhaust port or ports in plate (9) are closed by the valve only during the
return stroke.
It will therefore be seen that during the down stroke the low pressure portion of
the cylinder is open to the exhaust at both ends, that is on both sides of the piston,
and also the opposite end of the high pressure portion of the cylinder to that at
which the live steain from the boiler is admitted, so that the low pressure piston is
moving in equilibrium, and the effective pressure of the steam on the high pressure
piston is its absolute pressure, less the pressure of the exhaust, which in non-
condensing engines is just above the pressure of the atmosphere, and in condensing
engines the pressure due to an imperfect vacuum. During the return stroke only
that end of the low pressure portion of the cylinder, opposite to that at which steam
is admitted is open to the exhaust through passage (12) and port or opening into the
cylinder (13).
The steam used on the down stroke in the high pressure cylinder enters the other
end of this portion of the cylinder by passage (6) consequently the pressure on both
sides of the high pressure piston being the same, this piston is moving in equilibrium,
and the effective pressure of the steam on the low pressure piston is its absolute
pressure less tho pressure of the exhaust.
Therefore whether these cylinders are applied to condensing or non-condensing
engines the steam is employed both on the high and the low pressure pistons at its
absolute pressure, less a loss only of the pressure of the exhaust, as hereinbefore
nanied, a result I believe not hitherto attained in engines of this type.
Cylinders so constructed may be used in stationary, locomotive, and marine
engines, also for pumping engines, pile drivers, steam haminers and similar
machines.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
The arrangement and combination of parts, ports, passages, and exhaust chamber,
n the construction of the cylinders of compound steam engines as and for the
objects and purposes herein described, and the particular arrangements of same shewn
n Figs. 1 & 2.
WM. J. NORRIS.