Year: 1899

page_text: I, JOHN DAVIDSON, of 8, Trafford Road, Eccles, in the County of Lancaster,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has reference to steam engines, in which the expansion of the
steam is carried out in separate cylinders of successively larger diameter; and
the invention has for its object, to provide improvements in connection with
engines of this kind, primarily triple compound engines, in which, the distribu-
tion of steam is effected by the pistons of the said engine, which thus act as
valves, the high pressure or first cylinder alone having the supply of steam to it
controlled by a valve, and by which the equalization of range of temperature
in the cylinders is better equalised, and from which the indicator cards shall
closely approximate, or be similar, generally, to those produced by a triple com-
pound engine with three valves distributing the steam to and from the cylinders.
The invention or improvements will be described in connection with a triple
compound engine having the pistons and the three cylinders working on cranks
at equal distances apart or substantially equal distances apart.
According to this invention, in an engine of the kind referred to, having a
single steam distribution valve connected with the high pressure cylinder, and
in which the pistons of the successive cylinders govern the distribution and flow
of steam through the engine, the steam, in exhausting from one cylinder to the
other, is exhausted from the receivers of or connected with the cylinders, and
through a port in the head of the pistons, and, generally, through the interior
of such pistons. By this means the steam, by means of the valve in connection
with the first cylinder, and by means of the arrangements and construction of
the piston of the first cylinder, and ports leading to the second and to the third
cylinder respectively, the exhaust from the one cylinder to the other will be
opened and made to take place at about 90, to 92 per cent. of their stroke, in-
stead of much earlier.
the
In carrying this method out in connection with a single acting engine where
one end of the cylinders serves as a receiver or part of the receiver, the pistons,
or those of the first and second cylinders are hollow, and closed at one end, and
having a port or ports in their head through the periphery. In this case,
steam, as regards the first cylinder, passes therefrom through the port con-
trolled by the valve into the valve case, and thence into the bottom end of the
high pressure cylinder, and then through ports in the piston head, into the port
connecting the high and intermediate cylinders, and go to the back or active
end of the intermediate cylinder. The steam, in exhausting from the inter-
mediate cylinder, is governed by the piston of the high pressure cylinder, which
acts as a valve, and makes communication between the top and bottom of the
intermediate cylinder by way of the steam port, and an exhaust port leading
from the high pressure cylinder to the inactive end, which acts as the receiver;
and by this means pressure is retained in the working stroke of the intermediate

page_text: pistons to about the point referred to, and is then exhausted through the
cylinder ports governed by the high pressure pistons, through the hollow inter-
mediate pressure pistons, by way of the ports in the head of same, into a short
port directly connecting the intermediate and low pressure cylinders; and the
exhaust from this cylinder to a condenser or the atmosphere is governed by an
intermediate pressure piston, as in the other case.
In this construction, direct communication between the cylinders by their
connecting ports over the back ends of their pistons may take place at the extreme
end of the stroke, but this does not control or effect the exhausting period or
points above referred to.
The invention is not restricted to the particular arrangement above referred
to, but may be applied to double acting engines, and engines having different
dispositions of cylinders.
Dated this 10th day of July 1800
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.
I, JOHN DAVIDSON, of 8, Trafford Road, Eccles, in the County of Lancaster,
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 has reference to steam engines, in which the expansion of the
steam is carried out in separate cylinders of successively larger diameter; and
the invention has for its object, to provide improvements in connection with
engines of this kind, primarily triple compound engines, in which the distribu-
tion of steam is effected by the pistons of the said engine, which thus act as
valves, the high pressure or first cylinder alone having the supply of steam to it
controlled by a valve, and by which the equalization of range of temperature
in the cylinders is better effected, and from which the indicator cards shall
closely approximate, or be similar, generally, to those produced by a triple com-
pound engine with three valves distributing the steam to and from the cylinders.
According to this invention, in an engine of the kind referred to, having a
single steam distribution valve connected with the high pressure cylinder, and
in which the pistons of the successive cylinders govern the distribution and flow
of steam through the engine, the steam, in exhausting from one cylinder to the
other, is exhausted from the receivers of or connected with the cylinders, and
through a port in the head of the pistons, and, generally, through the interior
of such pistons. By this means the steam, by means of the valve in connection
with the first cylinder, and by means of the arrangements and construction of
the piston of the first cylinder, and ports leading to the second and to the third
cylinder respectively, the exhaust from the one cylinder to the other will be
opened and made to take place at about 90, to 92 per cent. of their stroke, in-
stead of much earlier.
The drawing hereto annexed shews a single acting engine according to this
invention, wherein one end of each of the cylinders serves as a receiver or part
of the receiver, and the pistons of the first and second cylinders are closed at
one end, having a port or ports in their head through the periphery.
Referring to the drawings, a, i and o are the high pressure, intermediate
pressure, and low pressure cylinders, respectively, a¹, and o' are the pistons

page_text: of these three cylinders, respectively, and b is the one valve which distributes
the steam and controls the exhaust of steam of the high pressure cylinder. The
three pistons are assumed to be working in connection with cranks of a crank
shaft set at equal distances apart, or substantially equal distances apart.
This high pressure cylinder crank is set at such an angle in relation to and
leading the intermediate pressure cylinder crank, as to be in similar relation to
it as an ordinary slide valve eccentric would be, viz., about 129°. And similarly,
the intermediate pressure cylinder crank should lead the low pressure cylinder
crank by about 129°.
The distribution valve shewn in the drawings is of the piston type, steam
from the supply pipe being admitted into the annular space about the valve, and
the space in the valve case d; and for a portion of the stroke of the high
pressure piston al during which steam is admitted to the cylinder a through the
port c,
this annular space of the valve will put the annular space or port and
the port c in communication; while during the rest of the outstroke, the port a
will be covered by the upper end of the valve.
With regard to the actions of the first cylinder «, and its piston a', when
the piston has travelled the greater part of its stroke-say to about 90% of the
outstroke the cylinder a is opened to its receiver-which is comprised of the
space within the valve case d, and the interior of the valve b, and the front end
of the cylinder a, and the interior of the piston a—by the valve uncovering
the port ; whereupon it exhausts into this receiver space, and this exhaust
steam passes by way of the ports a² in the piston head, which then communi-
cates with the port e, to the back end of the cylinder i, the piston ¹ of which
will be at the upper end of its stroke.
This communication will exist during a part of the return stroke of the
piston a, viz., about 16 % of such stroke, as well as about 16 % of the outstroke
of this piston, when the communication by way of the ports a² and e is cut off
by the metal of the piston a, and the steam so supplied to expands, pressing
the piston outwards. In the rest of the return stroke of the piston of the
cylinder a, it is open to the receiver space, namely the valve case d and the
interior of its piston, and the pressure remains practically constant until the
valve closes the port e, and compression commences.
The steam admitted to the intermediate pressure cylinder i, through the port e
is expanded in pressing outwards the piston ; and when this piston is near the
end of its stroke, say about 90% of the stroke, this cylinder is put in communi-
cation with its receiver (which consists, in the case shewn, of the opposite end
of the cylinder and the interior of the piston), by means of the port of the
piston al, which will, at this time, have put the two ports e and e¹ in communi-
cation; and this exhaust from the upper end of the cylinder to the lower
end, is caused to continue until the piston is nearing the top end of its stroke
(say about 80% of its stroke), by arranging or constructing the port a³ and the
entrances of the ports e e', to suit, when the high pressure piston a¹ will be
moved downwards, and cuts off the communication, by closing one of the ports;
whereupon compression in the cylinder i commences.
But during the out stroke of the intermediate pressure piston ¹, that is, when
this piston is approaching the outer end of its stroke (say about 84% of its
stroke) at which time the low pressure piston will be at the top end of its stroke
-the ports in the head of this piston becomes uncovered by their passing
over the port between the low pressure cylinder and the intermediate pres-
sure cylinder i, so putting the receiver end of the cylinder and piston ¹ in
communication with the low pressure cylinder, and supplying steam to this
cylinder. And this supply will be continued for that part of the end of the
down, and an equal part of the commencing of the up stroke of the pistón 22,
while the port is open to the port j, after which the communication is cut off,
and the steam in o expands.
This expansion goes on to near the end of the outward end of the stroke of

page_text: the piston o¹, at which time the intermediate piston 2, by means of an annular
port in its lower end, makes communication between the port and the port 7,
which is the final exhaust port from the engine; and these ports are so arranged
that they remain open until the low pressure piston o¹ has travelled, say about
80% of its upstroke, when the communication is broken, and the compression
in o takes place.
The action of the high pressure piston with regard to the intermediate pres-
sure piston; and the action of the intermediate pressure piston with regard to
the low pressure piston, are precisely similar to the actions of ordinary slide
valves, driven by eccentrics.
As a modified mode of action to that above described, the high pressure
pistons and cylinders may be constructed and adapted to put this cylinder, and
the intermediate pressure cylinders in direct communication with each other
at the extreme end of the stroke over the back end of the high pressure piston.
And the intermediate pressure piston, and the intermediate pressure cylinder and
low pressure cylinder may also be adapted to act in the same way; but the
former method of working and arrangement is more advantageous and preferred.
A double acting engine according to this invention, and constructed as shewn
in and set forth with reference to the drawing, consists of two sets of cylinders
and pistons, similar to those shewn in the drawing, but each cylinder and piston
being inverted, so that the open ends of the pistons face each other. The two
pistons in each case will be fastened to the same piston rod, and the receiver
space or part of the receiver space will exist between these two pistons. There
will of course be no intermediate stuffing boxes, the two portions of each double
cylinder being continuous and open from end to end.
By the above mode of operating an engine of the character referred to, and
arranging that the distribution of steam to and from the cylinders and receivers
takes place in the manner herein described, the range of temperature in the
cylinder is more nearly equalized, and the efforts and pressures, and periods of
inlet, and exhaust, will approximate more nearly those happening or existing
in a triple compound engine, with three valves distributing the steam to and from
the separate cylinders; and consequently an indicator card or diagram taken
from this engine would approximate, or be similar generally, to those taken from
such a triple compound engine.
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:-
1. A multiple cylinder steam engine, in which the steam supply to the high
pressure or first cylinder is distributed or controlled by a valve, and the steam
from this, and to and from the other cylinders, is distributed and controlled
from the pistons thereof acting in connection with ports leading to and from said
cylinders, and in the pistons; substantially as herein set forth.
2. A triple compound engine having a single valve for controlling or distri-
buting the steam to the high pressure cylinder; ports leading between such high
and intermediate, and intermediate and low pressure cylinders, and ports in the
high and intermediate pressure pistons for introducing steam from the high
pressure cylinder receiver, to the intermediate pressure cylinder, and from the
intermediate pressure cylinder receiver to the low pressure cylinder; substantially
as set forth, and as shewn in the drawing.
3. The combined steam engine having parts arranged and adapted to operate
as a whole, particularly as set forth with reference to and shewn in the drawing.
Dated this 10th day of April 1900
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.