AND CONNECTED WITH STEAM ENGINES
Year: 1866

page_text: LETTERS PATENT to Joshua Field, of the Firm of Maudslay, Sons, and
Field, of Lambeth, in the County of Surrey, Engineers, for the Inven-
AND CONNECTED WITH STEAM ENGINES"
Sealed the 28th May 1867, and dated the 29th November 1866.
PROVISIONAL SPECIFICATION left by the said Joshua Field at the
Office of the Commissioners of Patents, with his Petition, on the
29th November 1866.
I, JOSHUA FIELD, of the Firm of Maudslay, Sons, and Field, of Lambeth,
in the County of Surrey, Engineers, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN AND CONNECTED WITH STEAM ENGINES," to be as
follows:-
My Invention consists, first, in an improved method of adapting a high-
pressure cylinder on Woolf's system to the ordinary double piston rod or other
arrangement of steam engine. In my improved arrangement the small or
high-pressure cylinder instead of being placed altogether at the end of and
outside the large or low-pressure cylinder as heretoforc, is to a great extent
recessed into it, only projecting outside of it sufficiently to enable its valve or
valves to be readily got at. By this means a considerable saving of space is
effected: I prefer to recess the small cylinder into the front of the large onc
or at the end next the crank shaft, so as to allow the covers of both cylinders
to be readily removed, but when more desirable it may be recessed into the
back of the large cylinder. The piston and cylinder cover of the large

page_text: cylinder will have corresponding recesses in them, the piston of the small
cylinder is connected to the large piston by a rod passing through a steam-
tight joint in the back of the small cylinder in the ordinary way. For ordinary
working I prefer to shut off the steam in the small cylinder at about half the
stroke of the piston.
My Invention consists, secondly, in an improved arrangement of three
cylinder engines for working with a great amount of expansion, For this
purpose I place three cylinders side by side with a three-throwed crank shaft
immediately in front of them, the crank throws being placed at an angle
of 120° with each other. I admit the steam direct from the boiler into only
one of these cylinders (by preference the central one) where it may be shut
off at about half the stroke of the piston, or later if desired; after expanding
in this cylinder for the remainder of the stroke the steam passes through
suitable valves or passages into the other two cylinders, where the expansion
is carried on to a much greater extent. When desirable the high pressure or
central cylinder may have a shorter stroke than the two other cylinders, so as
to reduce its capacity and allow for a greater degree of expansion. In cases
where steam of very high pressure is used (say, from 80 to 150 lbs. per square
inch) I provide for a still greater amount of expansion by making the central
cylinder what is generally denominated annular with a small cylinder in its
centre. In this arrangement I admit the steam from the boilers into the
small central cylinder from which it passes and expands in the annular space
around it; after expanding in this annular space the steam passes into the
other two cylinders where the expansion is carried on to a still greater extent.
In this arrangement the steam may be expanded from 15 to 20 times according
to its initial pressure. For the purpose of readily starting these engines I
provide a passage from the slide jacket of the high-pressure cylinder into the
passages leading to the other cylinders and with shut off and safety valves, so
as to let steam direct into the two expanding cylinders.
My Invention consists, thirdly, of an apparatus for preventing the evil
consequences which often arise where superheated steam is used in steam
engines when it becomes superheated to too high a degree. It frequently
happens in consequence of the gases taking fire in the chimney uptake in the
neighborhood of the superheater that the steam becomes much too highly
superheated, and great damage is done to the valves, pistons, and cylinders of
the engine, and this action takes place generally without the knowledge of
the engineer. To prevent this evil I place an alarm whistle or bell in some
convenient position on the steam pipe or near to the engine, which whistle or
bell may be released and set in action by a pyrometer placed in the current of

page_text: the steam as it comes to the engine, so that if the temperature of the steam
should rise at any time too high (say, above 340°) the alarm whistle or bell
will immediately give notice to the engineer. By the same means I also
actuate a throttle valve placed at the junction of the pipe leading from the
superheater with the main steam pipe so as to shut off the superheated steam
and open the communication direct from the boiler.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Joshua Field in the Great Seal Patent Office on
the 29th May 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSHUA
FIELD, of the Firm of Maudslay, Sons, and Field, of Lambeth, in the County
of Surrey, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of November, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Joshua
Field, Her special licence that I, the said Joshua Field, my executors,
administrators, and assigns, or such others as I, the said Joshua Field, 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 AND CONNECTED
WITH STEAM ENGINES," upon the condition (amongst others), that I, the said
Joshua Field, 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.
NOW KNOW YE, that I, the said Joshua Field, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the Drawings hereunto annexed,
that is to say:-
My Invention consists, first, in an improved method of adapting a high-

page_text: pressuré cylinder on Woolf's system to the ordinary double piston rod or other
arrangement of steam engine. In my improved arrangements the small or
high-pressure cylinder instead of being placed altogether at the end of and
outside the large or low-pressure cylinder, as heretofore, is to a great extent.
recessed into it, only projecting outside of it sufficiently to enable its valve or
valves to be readily got at; by this means a considerable saving of space is
effected. I prefer to recess the small cylinder into the front of the large one
or at the end next the crank shaft, so as to allow the covers of both cylinders
to be readily removed; but when more desirable it may be recessed into the
back of the large cylinder. The piston and cylinder covers of the large cylinder
will have corresponding recesses in them, the piston of the small cylinder is
connected to the large piston by a rod passing through a steam-tight joint in the
back of the small cylinder in the ordinary way. For ordinary working I prefer
to shut off the steam in the small cylinder at about half the stroke of the
piston.
:
Figure 1 of the accompanying Drawings is a side elevation, Figure 2 a
front elevation, and Figure 3 a plan, partly in section, of a steam engine
constructed according to the first part of my Invention.
A, A, are the two large or low-pressure cylinders of the engine with double
piston rods B, B; C, C, are two high-pressure cylinders on Woolf's system;
which instead of being placed at the end of and outside the cylinders A, A;
are as before stated and as seen in the Drawings, recessed into them at their
front ends, only sufficient of the cylinders C, C, projecting as will enable the
valves to be readily got at. The pistons D and covers E of the large cylinders
A, A, are recessed, as shown, to receive the small cylinders. The piston F of
each small cylinder is connected to the piston D of the corresponding large
cylinder by a rod G passing through a steam-tight joint H.
My Invention consists, secondly, of an improved arrangement of three
cylinder engines for working with a great amount of expansion. For this
purpose I place three cylinders side by side with a three-throwed crank shaft
immediately in front of them, the crank throws being placed at an angle of
120 degrees with each other. I admit the steam direct from the boiler into
only one of these cylinders (by preference the central one) where it may be
shut off at about half the stroke of the piston, or later if desired; after expanding
in this cylinder for the remainder of the stroke the steam passes through
suitable valves or passages into the other two cylinders where the expansion is
carried on to a much greater extent. When desirable the high-pressure or
central cylinder may have a shorter stroke than the two other cylinders so as
to reduce its capacity, and allow for a greater degree of expansion.

page_text: Figure 4 is a side elevation, Figure 5 a front elevation, partly in section, and
Figure 6 a plan representing my improved arrangement of three cylinder engine.
A, B, C, are the three cylinders, and D is a three-throwed crank immediately in
front of them, the crank throws being, as before stated and as shown in Figure 7,
placed at an angle of 120° with each other. The steam from the boiler is
admitted directly into the middle cylinder B, where it is shut off at about half
the stroke of the piston; after expanding in the cylinder B for the remainder
of the stroke the steam passes through valves and passages E into the other two
cylinders A, C, in which the expansion is carried on to a still greater extent.
In cases where steam of very high pressure is used (say from 80 to 150 lbs.
per square inch) I provide for a still greater amount of expansion by making
the central cylinder, what is generally denominated annular, with a small
cylinder in its centre, as represented in Figure 8, in which F is a small
cylinder in the centre of the cylinder B. In this arrangement I admit the
steam from the boilers into the small central cylinder F, from which it passes
and expands in the annular space around it; after expanding in this annular
space the steam passes into the other two cylinders A and C, where the expan-
sion is carried on to a still greater extent. In this arrangement the steam
may be expanded from 15 to 20 times, according to its initial pressure. For
the purpose of readily starting these engines I provide a passage from the
slide jacket G of the high-pressure cylinder into the passages leading to the
other cylinders A and C and with shut off and safety valves, so as to let steam
direct into the two expanding cylinders.
:
My Invention consists, thirdly, of an apparatus for preventing the evil
consequences which often arise where superheated steam is used in steam
engines when it becomes superheated to too high a degree. It frequently
happens in consequence of the gases taking fire in the chimney uptake in the
neighbourhood of the superheater that the steam becomes much too highly
superheated and great damage is done to the valves, pistons, and cylinders of
the engine, and this action takes place generally without the knowledge of the
engineer. To prevent this evil I place an alarm whistle or bell in some con:
venient position on the steam pipe or near to the engine, which whistle or bell
may be released and set in action by a pyrometer placed in the current of the
steam as it comes to the engine, so that if the temperature of the steam should
rise at any time too high (say, above 340°) the alarm whistle or bell will
immediately give notice to the engineer. By the same means I also actuate
a throttle valve placed at the junction of the pipe leading from the superheater
with the main steam pipe, so as to shut off the superheated steam and open
the communication direct from the boiler.

page_text: This third part of my Invention will be fully understood on reference to
Figures 9, 10, 11, and 12. Figures 9 and 10 shew the simple form of appa-
ratus as applied to an alarm whistle. A is a steam whistle of the ordinary
construction mounted on a long hollow stem with a shut-off cock at B; this
whistle is shewn as placed on the top of the steam pipe, with which it com-
municates through the hollow stem and cock B; C is the lever of the cock
with a projecting pin fixed in its end; D, D, is a tumbling weight with lever
attached, fitting loosely on a pin on the end of the plug of the cock B; this
lever and weight are kept in position, as shewn, by one arm of a bell-crank
lever E, the other arm of which is actuated by the pyrometer G placed within
the steam pipe in the full current of the steam as it pases to the engines.
This apparatus or pyrometer G consists of a series of flat bars of copper and
iron attached together by brazing or other suitable means, as shewn in the
enlarged view at Figure 11, in which a represents the copper, and 6 the iron.
It will be readily understood that when these bars become heated they will,
from the unequal expansion of the metals of which they are composed assume
a more curved form and draw down the horizontal arm of the bell-crank
lever E, so as to cause the other arm when the horizontal arm has been drawn
down a regulated distance to release the tumbling lever and weight D, D, which
falling on the pin in the cock lever C will cause it to open the cock B, and
thus allow the steam to pass from the steam pipe to the whistle A, and give
notice to the engineer that the steam has become too highly superheated. The
apparatus should be so adjusted as to release the tumbling weight when the
steam arrives at the temperature of about 340°; the same apparatus may be
equally well employed for releasing a bell or spring alarum.
Figure 12 shews another form of apparatus which may be employed where
there is a long length of steam pipe available, also showing how the apparatus
may be made to actuate a throttle valve, so as to shut off the communication
with the superheated steam and open the communication with the common
steam. A is the steam pipe with two branch pipes B and C, the pipe B
leading the steam direct from the boiler, and the other C from the superheater.
D is a bracket fixed in the interior of the steam pipe, having the ends of two
rods E and F attached to it; the rod E is made of iron which may be tinned
or galvanized so as to preserve it from the action of the steam, and the rod F
is made of copper; the opposite ends of these rods carry a lever G, and
attached to the end of this lever is another iron rod J returning to a bell-
crank lever H, which is also carried by the fixed bracket D. It will be readily
understood that when these rods E and F become heated they will by their
unequal expansion cause the lever G to move in the direction of the dotted

page_text: line, and by the connecting rod also cause the bell-crank lever H to move, as
shewn by the dotted line, and draw down the horizontal arm of the releasing
lever, as before described. I is a second releasing lever, for the purpose of
releasing the throttle valve, shown by the dotted lines K; L is a lever on the
end of the spindle of the throttle valve K; it will be seen that when the one
end of the releasing lever I is drawn down by the action of the heat in the
iron and copper rods the other end will be raised so as to release the valve
lever L, and allow the throttle valve K to fall down so as to shut off the com-
munication with the superheated steam and open the communication with the
common steam. These arrangements shew examples of how this parts of the
Invention may be carried out, but they may be varied to suit the requirements
of different cases.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim,-
First. Constructing steam engines in which a high-pressure cylinder.or
cylinders on Woolf's system is or are recessed into the large cylinder or
cylinders, substantially as herein-before described and represented in Figures 1,
2, and 3 of the accompanying Drawings.
Second. Constructing three cylinder engines according to the arrangement
or arrangements herein-before described and represented in Figures 4 to 8 of
the accompanying Drawings.
Third. The employment in or in connection with steam engines of apparatus
arranged and acting substantially as herein-before described and represented
in Figures 9 to 12 of the accompanying Drawings, for sounding a whistle,
bell, or alarum, or for actuating a throttle valve so as to close the superheated
steam pipe and open the common steam pipe, or for both sounding a whistle,
bell, or alarum, and for actuating a throttle valve when the steam becomes too
highly superheated.
In witness whereof, I, the said Joshua Field, have hereunto set my hand
and seal, the Twenty-ninth day of May, One thousand eight hundred
and its coron