Improvements in Steam Engines.
Year: 1899

page_text: Date of Application, 4th Feb., 1899-Accepted, 14th Oct., 1899
COMPLETE SPECIFICATION.
Improvements in Steam Engines.
We, JOHN DAVIDSON, of 8, Trafford Road, Eccles, in the County of Lancaster,
Engineer, and THOMAS REGINALD HAMPSON, of 20, Curzon Park, Chester, in the
County of Chester, 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, mainly, to steam engines of the triple com-
pound type, that is to say, an engine in which the expansion of the steam is
carried out in three separate cylinders of successively larger diameter.
The
object of the invention has been chiefly to construct an engine. that will give an
even turning effort to the shaft, and at the same time to be very simple,
yet economical, and be capable of running at high speed; and, furthermore, to
so arrange and operate an engine of this type, that only one steam distribution
valve and valve gear is required and used.
The improvements in steam engines' according to our invention are illustrated
in the accompanying drawings, and they will be described by the aid of these
drawings; the same letters and figures of reference being used in the several
views, representing the different modifications, to denote the same or equivalent
parts, wherever they occur.
In the drawings, Figure 1 is a sectional elevation shewing a double acting
engine provided with our improvements.
Figure 2 is a sectional elevation, illustrating our improvements as applied to.
a single acting engine.
Figure 3 shews a modification of a duplex tandem engine according to our
invention.
:
Figure 4 shews a modification under the invention, in which the intermediate
and low pressure cylinders are in annular arrangement.
Figures 5, 6, 7 and 8; and Figures 5, 6, 7 and 8 are diagrammatic views
illustrative of the relative positions of pistons and ports of the high pressure
and intermediate pressure cylinders, and different relative positions of the cranks
at different points of the strokes, in the case of the single acting engine shewn
in Figure 2.
:
Referring now to the drawings, and in the first instance to Figure 1, a, i and o
are high pressure, intermediate pressure, and low pressure cylinders, respectively,
of the engine and a¹, i¹, and o¹, are the pistons of these three cylinders,
respectively. b is the one steam distribution valve of the engine, distributing
steam to the high pressure cylinder. In the case shewn, this valve is of the
piston type, the upper and lower heads or ends of which work over and in con-
nection with the steam ports c; and have a tubular stem 61, connecting them
together. Steam is introduced into the annular space d' of the valve case d,
about the tubular part b¹ of the valve, the steam lap of the pistons of the valve
being on their inside edges; and the space within the valve, and the ends of
the valve case, constitute the receiver space to this, the first cylinder of the
engine.

page_text: The pistons of the cylinders are connected to their respective cranks by piston
rods and connecting rods, in any suitable or known way.
The piston a¹ of the high pressure cylinder a is a double piston, the part
between the piston heads of which is of smaller diameter, and forms an annular
passage or port about it. The exhaust steam from the cylinder a is controlled
by the piston a', and the flow from this cylinder to the intermediate pressure
cylinder is by way of ports e, the openings of which into the cylinder a (which,
say, extend all round) are governed by the piston heads a¹; whilst the space f
about the central portion of these pistons heads, and the cylinder casing com-
municating with it, constitutes the receiver to the intermediate cylinder. The
openings of the ports e out of the cylinder a is near the ends of the stroke of
these pistons a¹, in the opposite ends of the cylinder a; and the opening of the
ports e into the opposite ends of the cylinder i is at the outer ends of this
cylinder. The piston 21 of this intermediate cylinder is an elongated double-
headed piston; and serves to control the supply of exhaust steam from its
cylinder to the low pressure cylinder o, the ports communicating between i
and o being designated j. The piston ¹ is similar to a¹; and the central part
joining the two heads is of reduced diameter, and constitutes a passage, serving
as an exhaust passage in the cylinder from the low pressure cylinder o, to an
opening shewn in dotted lines in the cylinder i, constantly open to this
annular port of . The steam ports j, as will be seen, are short, and lead
directly from the cylinder i to the cylinder o; consequently the clearance capacity
is small, and waste of steam in the low pressure cylinder ports avoided.
In action, when the high pressure piston a' is at the extreme end of its stroke
at one end of the cylinder a, the steam port e belonging to that head is
uncovered by the head of the piston valve b, and steam enters, the cylinder;
and the supply is continued for the desired portion of the stroke of the high
Then; when the cylinder
pressure piston, when it is cut off by the valve.
approaches the outer end of its stroke-say about the point as illustrated in the
crank diagram in Figure 5, and also shewn in Figure 5-one of the piston
heads a¹ uncovers one of the ports e, and steam exhausts from a to one of the
ends of the intermediate pressure cylinder i; and this communication is con-
tinued until the hight pressure piston has reached a certain point in the upward
stroke, viz. the point at which opening commenced, when it closes this port e, and
the steam admitted to expands. This point of cut off will be about that repre-
sented in Figures 6 and 6. Then the steam in i expands until the piston has
reached a point as shewn in Figure 7, which is equivalent in its stroke to the
point reached by the crank of the intermediate pressure piston shewn in
Figure 7, when it uncovers one of the ports i, and the steam exhausts from i,
into the low pressure cylinder o, the piston of this cylinder being at or near the
end of one of its strokes. This communication will continue during the portion
of the stroke of o¹, until a point in the return stroke of is reached-which
corresponds to the point at which the opening to o commenced-when it is cut
off and expands. When the piston o¹ has reached the end of its stroke, the
cylinder o will be put in communication with the exhaust port 1, and the open-
ing k, by the uncovering of the port ; by the inner edge of the piston . This
communication maintained until the piston o' has travelled the greater portion
of its stroke, when compression commences.
During a portion of the return stroke of the high pressure piston a¹, namely,
from about the point indicated in Figures 6 and 6, the piston will be com
pressing into the receiver, that is, the space inside the valve b and the ends of
the valve case d; and when this communication is cut off, and steam supplied
from the annular port d', the opposite end of the cylinder a, will then be put in
communication with the internal space of b, which acts as the receiver then for
this end.
:
With regard to the exhaust from the non-active end of the intermediate pres-
sure piston ¹, whilst steam is acting at the opposite end on the piston, this end

page_text: will be in communication with the spaces f and that for a portion of its stroke,
the entrance of the port e being uncovered to the inner edge of the piston
body a at that end; and it will remain open until this inner edge closes it,
when compression in i commences. The steam is compressed until the end of
the stroke of the piston ¹ is reached; when the steam from the high pressure
cylinder passes from it into i. The duration of this compression depends upon
the length of the piston bodies a¹, and the proportion of the stroke which it
takes in moving between the point at which e is closed by the inner edge of
the piston body and that when the opening of it takes place by the outer edge
of the piston body.
:
Then with regard to the operations within the low pressure cylinder on the
side of the piston which is not being acted on by steam, the steam will be
exhausting by way of the port j, the annular space round the intermediate part
between the piston heads , and the outlet k, for the greater part of its stroke;
when the port j will be closed by the inner edge of one of the ends of the
piston ', and compression in o will take place, until this port is open to one
of the ends of the cylinder i, by. its being uncovered by the back edge of 2¹.
Obviously, the exact degree in the relative positions of the three cranks and
pistons of this engine, at which the openings and closings of these several ports
take place, may vary to a considerable degree, but we will now describe and
trace, as an example, the distribution of steam, and the periods in the strokes
of the several pistons at which admission, release, closing, compression, and
other factors in the complete operation in the engine with regard to steam dis-
tribution, from the point of admission of steam of full pressure, to that of
discharge from the low pressure cylinder. This example, of course, will be
within the limits of the range of variations, at which these several actions and
functions can take place; and its employment will give a satisfactory and
economical result as a whole, and throughout the engine.
The engine in connection with which these complete operations will be
described is a double acting three crank engine as illustrated in Figure 1.
With regard to the relative arrangement of cranks, assuming the interme-
diate pressure cylinder crank to be taken as the one in relation to which the
others are to be considered, then the high pressure crank may lead the inter-
mediate pressure cylinder crank by about 127°; and the intermediate pressure
crank will lead the low pressure crank by about 1320 of the circle. The lead
of the low pressure over the high pressure cylinder will, therefore, be 101°.
First, with regard to the admission of steam to the high pressure cylinder,
this is under the control of the valve b, and its admission and operation may take
place in the usual way; and it may, therefore, be admitted and cut off at the
cylinder ports c, at practically any point. Or, it may also, if desired, be under
the control of an automatic shaft governor.
Assuming then, so much, the behaviour, actions, etcetera, of the various
pistons, acting as valves in the distributon and manipulation of the steam
throughout the engine, will now be specified.
HIGH PRESSURE PISTON AS THE VALVE OF THE INTERMEDIATE CYLINDER.
Top end: The piston a¹ opens port e to intermediate pressure cylinder at 83%
of down stroke; and closes this port at 17% of upstroke. After this, the steam
in cylinder a in the remaining part of upstroke is in communication with its
receiver, viz., the interior of the valve b; and is then compressed prior to steam
opening.
Bottom end: The piston a¹ opens port e to the intermediate pressure
cylinder, at 76% of upstroke, and closes the port at 24% of downstroke; this
end of the cylinder being open to the receiver for the remaining portion of the
stroke, as just described.

page_text: INTERMEDIATE PRESSURE CYLINDER.
Top end: Steam enters from high pressure cylinder for 65% of downstroke,
when it is cut off by the high pressure piston; the steam then expands for a
period, and at 82% of its downstroke it opens the port j to the low pressure
cylinder; and it-that is the piston --closes this port at about 17.5% in its
upstroke. The opening to the receiver of the other end of the cylinder may
take place simultaneously with. the opening of the low pressure cylinder, in
which case the compression will take place during 625% of the stroke of the
piston. Or, this opening to the receiver may take place at a point representing
90% of the stroke, in which case the compression will be about 15% of the
stroke.
Bottom end-Steam enters this end from the high pressure cylinder for 60%
of the stroke of 1; it is then cut off, and subsequently at 76% of the stroke
of it opens the part j to the low pressure cylinder, and then closes this port
at 24% of its downstroke; the compression in this cylinder will be 5% of the
stroke in the case of the opening to the receiver, being simultaneous with the
opening to the low pressure cylinder; and 15% compression if the opening to
the receiver takes place at 92% of the stroke.
Low PRESSURE CYLINDER.
Top end: Steam from the intermediate pressure cylinder enters this cylinder
for 66% of the stroke of its piston, when it is cut off by intermediate pressure
cylinder, by the piston closing the port j. It then expands, and at 92% of
the stroke it is released, and passes away by the port 1, and annular space round
the piston, to the outlet ; and the compression at the end of the stroke will
be 15%.
:
Bottom end: With regard to this end of this cylinder the cut off, release,
and compression will be 60 per cent., 93 per cent., and 15 per cent., respectively of
the stroke.
Referring now to the modification shewn in Figure 2, this shews a single
acting engine, having the main general characteristics and arrangements of the
engine shewn in Figure 1. In this case, the admission, distribution, and
exhaust of the steam to and from the several cylinders, in their active strokes
may be taken to be substantially similar to that set forth with reference to
Figure 1, but the idle or non-active end of the cylinders in this case are some-
what modified, and they are as follows:-
The receiver to the high pressure cylinder and piston is the space within the
casing, and within the tubular part 6 of the valve b; that is, the greater parts
of the valve casing; and it is in constant communication with the lower end
of the cylinder a by the ports c¹, the upper steam port c only being controlled
by the valve b.
The idle end of the intermediate pressure cylinder forms a receiver to the
upper end of the cylinder, as in the upstroke of this piston a', and during the
upstroke of, the upper end of this cylinder is put in communication with
the lower end by the annular passage round the intermediate part of the
piston a, which puts the port e in communication with the bottom end of i by
a port e¹.
The idle end of the low pressure cylinder o has a receiver or chamber o³, which
is always in communication with the exhaust, and at the outer ends of the
stroke of the piston o', this piston, by uncovering a port o², communicating
between 3 and the upper side of the cylinder, forms a natural drain for this
cylinder.
Figures 5, 5 to 8, 8, illustrate diagrammatically several relative positions
of the pistons of the high and intermediate pressure cylinders, during the
moments of important actions of steam distribution, manipulation, and use in

page_text: the several cylinders; and the positions of the cranks connected with these
cylinders, in the stroke corresponding with these positions.
For instance, Figures 5 and 5 illustrate the point of exhaust from the
cylinder a to the cylinder i; Figures 6 and 6 illustrate the point of cut off
of steam from a to i; Figures 7 and 7* illustrate the point of putting the upper
and lower ends of the cylinder i in communication with each other, and so
making the cylinder its own receiver; whilst Figures S and 8* illustrate the
point at which this communication is cut off, and compression in begins.
Figures 5 to 8 also illustrate the controlling action of the intermediate pres-
sure piston in connection with the admission and exhaust ports ; and of
the low pressure cylinder o, shewing the periods in stroke of the piston ¹at
which these ports j, l, are open at the interior of i, closed wholly by the piston 2,
and are in communication with each other while out of communication with i.
Figure 4 shews the arrangement of a triple compound engine having a distri-
bution of steam, and a mode of action, substantially similar to that set forth
with reference to Figure 2, but the arrangement of the cylinders is different.
The low pressure cylinder o, instead of being at the side of the intermediate
cylinder i, is at once both in tandem arrangement with it, and concentric; that
is to say, the cylinder o is at a lower level than the part of the cylinder i which
is traversed by the piston ; and the cylinder o, and piston o are annular;
the septum between o and being the continuation of the cylinder i.
In this case, as in the others above described, the exhaust port j from the
intermediate pressure cylinder to the low pressure cylinder is short; and the
clearance in the cylinders is therefore small. And, this port is uncovered
by the piston during the outer portion of its stroke, for the exhaust of steam
from too; while during the most of the upstroke, prior to closing for com-
pression, the ports ; form a communication between the upper part of the
cylinder o and the lower part both cylinders o and i, which are common; and
which are open to the exhaust by means of the pipe k. In this case, there will
be two low pressure cranks instead of one, as in the above engines.
The engine shewn in Figure 3 is a modification of the double acting engine
shewn in, and set forth with reference to Figure 1. In it, in lieu of the single
intermediate pressure cylinder, two of such cylinders are employed in tandem
arrangement, one above the other; the pistons i being on the same connecting
rod. In this case, the ports e communicating with the cylinder a, are bifer-
cated, one part leading to the upper cylinder i, and the other to the lower
cylinder . Thus the double piston a¹ of the high pressure cylinder a, serves
also as a valve for the distribution of steam from this cylinder to the two inter-
mediate pressure cylinders i. And in like manner, the steam from the
cylinders may be distributed to two other low pressure cylinders. Or, as a
modification of this, a three crank engine with one valve may have one
high, one intermediate, and two low pressure cylinders, acting in the manner
described.
In engines of this latter character, under Figure 3 and its modifications, will
provide a high power, with a short length of engine, and a small space occupied.
Although the invention has been mainly described as applied to an inverted
vertical engine, having three cylinders, side by side, it is not restricted to this
arrangement, as it may be applied to engines having different positions and to
different relative arrangements in which the expansion of the steam is carried
out in three stages.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
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 the other cylinders is distributed and controlled by the pistons

page_text: thereof, acting in connection with ports leading to and from said cylinders; the
said cylinders, pistons, and ports, being arranged in relation to each other, sub-
stantially as herein set forth and shewn.
2. In a triple compound engine, having three cylinders and cranks, the several
modes of distributing the steam by the pistons thereof, using such steam and
working the high pressure, intermediate pressure, and low pressure cylinders
thereof, respectively; substantially as set forth.
3. The triple compound engine, having a single valve for controlling or dis-
tributing the steam to the high pressure cylinder, and having ports arranged
between the high and intermediate, and between the intermediate and low
pressure cylinders, and the pistons of these cylinders, and cranks; arranged
substantially as set forth with reference to Figure 1; Figures 2 and 5, 5^
to 8, 8 of the drawings.
4. In a compound steam engine of the kind herein referred to, the combina-
tion in connection with a single cylinder, and the piston thereof, of duplex
cylinders, to both of which steam from the said single cylinders is distributed by
the pistons thereof; substantially as herein set forth.
5. In a triple compound engine of the type herein referred to and claimed,
the arrangement of the high pressure cylinder, and combined annular and
tandem intermediate and low pressure cylinders; substantially as herein set
forth.
6. The combined steam engine, having parts arranged and adapted to operate
as a whole; particularly as set forth with reference to Figure 1; Figure 2;
Figure 3; and Figure 4, respectively, of the drawings.
Dated this 4th day of February 1099.
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.