IMPROVEMENTS IN STEAM ENGINES
Year: 1870

page_text: LETTERS PATENT to William Dawes, of Kingston Grove, Leeds, in
the County of York, Engineer, for the Invention of "IMPROVEMENTS
IN STEAM ENGINES."
.Sealed the 28th April 1871, and dated the 1st November 1870.
PROVISIONAL SPECIFICATION left by the said William Dawes at the
Office of the Commissioners of Patents, with his Petition, on the
1st November 1870.
.
I, WILLIAM DAWES, of Kingston Grove, Leeds, in the County of
York, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM ENGINES," to be as follows:-
Firstly, my Invention consists of an improved arrangement and con-
struction of "compound expansive condensing horizontal engine,"
wherein greater compactness and at the same time accessibility of parts
individually are obtained, embodying also greater strength and rigidity
of construction by the manner in which the main parts are united to
each other, so as to equalize the power to resist the strain or “thrust "
through the entire engine.

page_text: To achieve or carry out the before-named object I use three new or
novel features of construction (under several modifications according
to circumstances or the nature of the duties required from the engine),
viz., I place one steam cylinder upon the other horizontally or nearly
so; I divide the condensor either partially or entirely into two, placing
it or them so that the connecting rod or rods may work through or
between them; and I use two air pumps half size, in lieu of one of the
usual size, these being worked or actuated direct from the two sides of
the cross heads," or other convenient parts of the engine.
"
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For stationary engines " I prefer to place the small or "high-
pressure" cylinder upon the. " low-pressure" cylinder, with the back end
slightly elevated, so that its "centre line" shall also point or converge
to the centre of the crank shaft, and so far " sideways" or hori-
zontally from or out of the "centre line" of the under cylinder that the
two connecting rods (one for each cylinder) can work "side by side'
upon one and the same" crank pin" or "bearing," the condensors in this
arrangement (with their "air pumps ") being placed on each side of
the connecting rods, immediately in front of the "slide bars or guides
of the " piston caps or cross heads," these being carried' or sup-
ported by the condensors and cylinders and firmly," tying " or "staying"
them together; and as a further means of obtaining perfect rigidity
stay" or girder" can be fixed longitudinally over head," from
the tops of the condensors to the upper side of the small cylinder, also
the crank shaft pedestal or pedestals can be formed into strong "angle
brackets" and fitted to the condensors and bed plate to complete the
entire tie or stay from the cylinders to the crank shaft, to prevent the
possibility of the "bed" or any part "springing" from the pressure and
thrust of the steam. The two air pumps may be actuated as previously
described direct from either of the cross heads or slide blocks.
a
cr
"
This arrangement or modification of my improved engine is especially a
suitable for " factory' or other engines, which are required to work
one way only, as it embraces the incidental advantage of the "low-
pressure" cylinder piston being a little in advance of the piston of the
high-pressure" cylinder, which improves the exhaust and the per-
formance of the engine.
"
"
For marine purposes I prefer to place the condensors and air pumps
at the end of the "bed or "sole plate" to balance the cylinders, with
the guides and "slide blocks between them, the action being "returned"
3

page_text: "
"
or reversed instead of "direct," the "crank shaft" being placed about
the centre of the engines; and I employ a triangular frame for trans-
mitting the power or action similar to those used (vertically) in the
engines known as "steeple engines" but working horizontally, the small
or connecting rod end of the same with the guide blocks working
between the condensors, and the large or radial end or bar, (also running
in guides) receiving the two piston rods which in this case are parallel
with each other, the, cylinders also being bored and fixed true and
parallel with each other and the "bed or sole plate," these and the
condensors being "tied" or "stayed" together by an overhead girder,
as in the before-described arrangement for stationary engines. The
positions of the piston rods in this bar are not necessarily central or
equally distant from top and bottom, but may be varied according to
the comparative power exerted by the high and low pressure pistons and
the distance below the centre at which the air pumps are attached, these
being in this arrangement actuated direct from two upright "cheeks
or bars fixed upon the sides of the before-named triangular frame, and
it may be well to state that this double air pump feature embraces
the advantage of enabling the engine to run at high speeds without
gearing or machinery to reduce the speed of the air pump pistons.
"
"
In either of the before-described arrangements of my improved engine
the steam valves may be of any convenient or desirable kind or descrip-
tion, and in some cases it may be desirable to carry the main exhaust
pipe "over head" taking advantage of its support or "stay" in lieu of
the before-named girder.
"
The second part of my Invention consists in obtaining the necessary
"lead
of the low-pressure cylinder valve, or, in other words, the
necessary difference in or between the "timing" of the valves of the
two steam cylinders, by actuating that of the high pressure cylinder by
or from the action or "valve gear "of the low-pressure cylinder by a
kind of adjustable "tappet action" arranged so as to give a little
"play" or time between the movement or action of the two valves, the
difference in the length of "stroke " or "travel" of the valves allowing
of this action, and, as will be evident, dispensing with the second or
extra excentric usually employed to effect this "timing" or "setting"
of the valves in compound engines.
The third part of my Invention consists in giving more freedom to
the exhaust from the ordinary "three port" slide valve than heretofore,

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especially desirable for the high-pressure valves of compound engines.
This I effect by the use of two "exhaust ports" in the "seat face," or
the one port" divided by an additional "bar" or "bridge." I also
make the exhaust passage or "hollow" in the valve itself double, with
a middle face or bar, and so spaced that at the moment of exhaust or
when the valve is just passing the central position the space between
these two "hollows" shall coincide with, and be exactly upon the centre
bar or bridge of the "seat face," and thus give a perfectly free passage
for the steam or "exhaust" without the impeding "ledge" which in
the ordinary arrangement of valve and ports the sides of the "exhaust
port" offer.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Dawes in the Great Seal Patent Office on
the 1st May 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
DAWES, of Kingston Grove, Leeds, in the County of York, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of November, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Dawes, Her special licence
that I, the said William Dawes, my executors, administrators, and
assigns, or such others as I, the said William Dawes, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
STEAM ENGINES," upon the condition (amongst others) that I, the said
William Dawes, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said William Dawes, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
Firstly. My Invention consists of an improved arrangement and
construction of "compound expansive condensing horizontal engine,"
wherein greater compactness and at the same time greater accessibility
of parts, individually, are obtained, embodying also greater strength
and rigidity of construction by the manner in which the main parts
are arranged and united to each other so as to equalize the power to
resist the strain or "thrust" through the entire engine.
1
To achieve or carry out the before-named objects or improvements I.
use three new or novel features of construction (under certain modifica-
tions, according to circumstances or the nature of the duties required from
the engine), viz., I place one steam cylinder over or upon the other in a
manner herein-after described. I divide the condenser either partially
or entirely into two, placing it or them so that the connecting rod or
rods may work through or between them, and I use two air pumps
"half size" (or area) in lieu of one of the usual size, these being worked
or actuated "direct" from the "
cross head or other similar convenient
part of the engine.
"
"
"
By referring to the accompanying illustrations it will be seen that I
fix the small or high-pressure cylinder upon or over the "low-
pressure," cylinder in such a manner that its centre line shall also point
or converge to the centre of the "crank shaft," the back end being.
elevated for this purpose, and so that the angle formed by or between
the centre lines of the two cylinders or engines shall be about fifteen
degrees, and in lieu of either "cranking or "forking" the connecting
rods I prefer to place this smaller cylinder so far "sideways" or hori--
zontally from or out of the centre line of the under cylinder that the
two "connecting rods" (one for each cylinder) can work "side by side,"
upon one and the same crank pin" or bearing," though in some
cases where preferred for the sake of appearance or any other cause
either of the before-named methods or modifications may be adopted.
The condensers with their air pumps I place on each side of the said
connecting rods "immediately in front of the "slide bars" or guides
of the "
piston caps" or cross heads," these bars or guides being
supported the lower ones upon the "bed" or "sole plate-" and the upper
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ones by the condensers and the upper cylinder or "cylinder cover," and
firmly "tying" or "staying them together, and as a further means of
obtaining perfect rigidity (when the "exhaust or "eduction" pipe is
placed under the engine instead of "over head") a "stay" or "girder "may
be fixed longitudinally from the tops of the condensers to the upper
side of the small cylinder, also the "crank shaft" pedestal or pedestals
can, by this arrangement, be formed into strong "angle brackets" and
firmly fixed and fitted to the condensers and the "sole plate," and thus
complete the entire "tie" or stay" from the cylinders to the "crank
shaft," to prevent the possibility of any "spring" or movement in those
parts of the engine which should be perfectly rigid and immoveable.
The air pumps are so placed in their condenser or condensers, as the
case may be, that the "air pump rods" "face," and can be united to the
"socketted" ends of a suitable "cross bar" fixed (by preference) across
and upon the lower or * low-pressure" cylinder, cross head," or
"cap."
"
::
This arrangement of engine is especially suitable for "factory" or
other engines which are required to work one way only (not reversible),
as it embraces the incidental advantage of the "low-pressure" cylinder
piston being a little in advance of the piston of the "high-pressure"
cylinder, which improves the "exhaust" and the combined action of the
two pistons; and through these the smoothness and performance of the
entire engine, also the double air pump feature embraces besides com-
pactness the advantage of enabling the engine to run at a higher speed
without "gearing" or machinery to reduce the speed of the air pump'
pistons.
"
"
The second part of my Invention consists in obtaining the necessary
"lead" of the low-pressure cylinder valve, or, in other words, the
necessary difference in or between the " timing
or "setting" of the
valves of the two steam cylinders by actuating that of the high-pressure
cylinder by or from the "action" or "valve gear
" of the low-pressure
cylinder by a kind of "tappet action" arranged so as to give a little
"play" or "idle time" (to the former) between the movement or action
of the two valves, the difference in the length of "stroke or "travel"
of the two valves allowing of this action and, as will be evident, dis-
pensing with the second or extra "excentric" usually employed to effect
this difference in the "timing" or "setting" of the valves in "compound
engines," embodying also the advantages of great facility in "setting"
65
"
.

page_text: or adjusting the two valves and of giving to the valve of the high-
pressure cylinder an increased speed whilst passing or reversing the
'ports" without increasing the entire "stroke" or "travel" for this
purpose.
"
The third part of my Invention consists in giving more freedom to
the "exhaust" from the ordinary "three port" or " locomotive slide
valve than heretofore, especially desirable for the high-pressure valves
of "compound engines." To effect this I use a double "exhaust port" in
the "seat face" or the "exhaust port" divided by a "bar" or "bridge."
I also construct the exhaust passage or "hollow" in the valve itself
double with a middle "face" or "bar" and so spaced that at the moment
of exhaust or when the valve is just passing its central position the
bar" between the two "hollows" shall coincide with and be
space or
exactly upon the before-named centre "bar" or "bridge" of the "seat
face," and thus give a perfectly free passage for the steam or
" exhaust"
without the impeding "ledge" or "shelf" which in the usual "make"
or arrangement of valve and ports the sides of the "exhaust port"
alternately offer. In some cases I dispense with the middle. ".bar" or
"bridge" in both "seat" and "valve," and by forming the two "hollows
of the valve into an enlarged double hollow with the centre portion
"rounded off" the steam or exhaust is directed into the exhaust port
without striking upon the said "ledge" or "shelf," and the desired
relief is thus obtained.
"
In the accompanying Drawings, Figures 1 and 2, Sheet 1, and 3 and 4,
Sheet 2, refer to the first part of my Invention; Figures 5 and 6, Sheet 2,
to the second, and Figures 7 and 8, Sheet 2, to the third part of my
Invention.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used
or carried into effect, I wish it to be understood that I do not confine
or restrict myself to the precise details which I have described or referred
to, as many modifications and variations may be made therefrom without
deviating from the principles or main features of the said Invention, but
what I consider to be novel and original, and therefore claim as the
Invention secured to me by the herein-before in part recited Letters
Patent is,
Firstly. The improved arrangement and construction of engine

page_text: Secondly. The improved arrangement and construction of "valve
gear" for "compound engines."
And, thirdly. The improved form or construction of the "three port'
slide valve and its ports for increasing the freedom of the exhaust,
essentially as or after the manner of the foregoing descriptions and
Drawings.
In witness whereof, I, the said William Dawes, have hereunto set
my hand and seal, this Twenty-ninth day of April, in the year of
our Lord One thousand eight hundred and seventy-one.
Witness,
CHARLES BRADFORD,
St. Mark's Road,
Leeds.
WILLIAM DAWES. (L.s.)