IMPROVEMENTS IN STEAM ENGINES
Year: 1875

page_text: LETTERS PATENT to Immer Fielden, of the City of Glasgow, in the
County of Lanark, North Britain, Engineer, for the Invention of
"IMPROVEMENTS IN STEAM ENGINES.”
Sealed the 16th March 1875, and dated the 1st January 1875.
PROVISIONAL SPECIFICATION left by the said Immer Fielden at the
Office of the Commissioners of Patents, with his Petition, on the
1st January 1875.
I, IMMER FIELDEN, of the City of Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN STEAM ENGINES," to be as follows:-
-
This said Invention has reference to certain improvements in the con-
struction of the cylinders of reciprocating steam or other motive fluid
engines, whereby considerable saving in steam and power and as a con-
sequence coal or fuel is effected in the use of such engines when fitted
with these improvements over or compared with those heretofore in use;
and the nature and novelty of the said Invention or improvements consist
in making the motive cylinders (either of the high or low pressure or
compound class) with moving ends instead of the usual fixed or cast-on

page_text: crank shaft or back of the crank, which would give the required motion
to the said rod and bell crank to turn cither end of the cylinder to tho
proper distance and at the proper time in relation to the crank and motion
of the piston. As by this arrangement the rod and lever require to havo
the same rise and fall in relation to the crank coming to and going from
its dead centre, the cam may be of a simple construction, as that of an
annular groove, for three-fourths of the circle, with a very flat, nearly
segmental curve joining these with the drop at the centre required, which
is so little graduated over the said fourth of the circumference left for it
that a good working cam action is obtained with not more than 1 to 3 of
a gradient, also suitable for either the forward action and reversing or
backing of the engines. The steam is admitted when the end cover has.
stopped its inward motion along with the piston through ports entering
the cylinder at these positive equal distances from both extreme ends of
the cylinder, made with valves to steam, and cut off and expand to the
said shortened end of the effective acting stroke of the piston, otherwise
as usual; a continuation of the port may be made in the screwed part
of the cylinder to allow of the escape of any steam which may be
confined between the end of the cylinder and the piston after passing
the port, more than would equalize the pressure inside and outside of the
end covers, to prevent friction on the screw which sustains the reacting
pressure and consequent loss of power in working these.
Although only one mode and means of fitting and moving the end
cover of the cylinder has been described, it will be evident to engineers
that various other mechanical equivalents or arrangements might be
adapted and used for the like purpose; as by fitting and moving the
ends as block pistons to follow the real piston at the same speed with a
little clearance between them for the required distance, before and after
the crank reaches and passes the dead centre, moved direct by cams or
other equivalents from the crank shaft, or a countershaft driven at the
same speed. These ends or re-acting block pistons being locked to
sustain the pressure of the steam when they reach the limit of their
inward traverse by as many bolts, pawls, or other equivalents, as may
be desired, ranged round and carried either on the outer ends of the
cylinder or the pistons themselves, simultaneously locked and unlocked
by any separate cam or other equivalent for the purpose, worked from
the crank shaft or other moving part of the engine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Immer Fielden in the Great Seal Patent Office on
the 28th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, IMMER
FIELDEN, of the City of Glasgow, in the County of Lanark, North
Britain, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of January, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Immer Fielden, Her special licence
that I, the said Immer Fielden, my executors, administrators, and
assigns, or such others as I, the said Immer Fielden, 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
Immer Fielden, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 Immer Fielden, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Sheet of Drawings, and to the letters and figures marked thereon, that is
to say:-
My said Invention has reference to certain improvements in the con-
struction of the cylinders of reciprocating steam or other motive fluid
engines, whereby considerable saving in steam and power, and as a
consequence coal or fuel is effected by the use of such engines (when
fitted with these improvements) as compared with those heretofore in

page_text: use. And the nature and novelty of my said Invention or improvements
consist in making the motive cylinders (either of the high or low
pressure compound class) with moving ends or pistons, instead of having
these stationary as the usual fixed or cast-on bottoms or covers, all for
the purpose of automatically following up the motion of the piston from
cach end for some distance (say as a maximum, equivalent to the per-
pendicular of an arc to the chord of one-fourth or one-sixth of the
revolution of the crank of the engine) so as to shorten the cylinder
always on the acting side, before admitting the steam or other motive
fluid, and thus cause it to act at once with its full force or pressure on
the piston when the crank is at a considerable angle on either side of
the dead plumb centre line, as say 45° or 30°, so as by its piston rod and
connecting rod to act on the crank to turn it through the best acting
part of its revolution, and which gives the full benefit of the expansion
of the steam to the end of the stroke, with a less capacity of cylinder
and measure of steam (instead of as usual admitting the steam at tho
turn of the centre), thus taking the full measure of the cylinder of
steam, which acts for a considerable time when it has no direct force in
turning the crank, but really spending its force in friction on the crank
pin and bearings of the crank shaft.
Various modes and means of constructing and fitting the pressure
resisting ends or pistons of the cylinder of an engine, that they may be
moved automatically at nearly the same speed as the piston (in accordance
with these my improvements as stated) may be adopted, by an arrange.
ment of mechanism or mechanical motion, primarily actuated by the
crank shaft, or it might be other continuous revolving or reciprocating
part of the engine. One mode and means of so shifting the new
pressure resisting ends or pistons of the steam cylinders would be to cut
a screw on the periphery of the said moving ends of the cylinder with a
pitch so coarse and so nicely fitted (with a packing ring or other equiva-
lent) into the ends of the cylinder, that by turning either end through
or by a stud joint to the extent of about a third of its revolution or
circumference in either direction it would be screwed into or out of the
cylinder to the desired maximum distance stated and required; and the
length of the chord of the arc passed through by the moving stud or
pin would be the measure or length of motion required by the arm of
the lever connected to it, say by a connecting rod and universal joint, or
otherwise; or these ends might be thus turned by tooth gearing or cam

page_text: mechanism instead of the said stud, connecting rod, and lever; but
when this lever is used it might be of the bell-crank form, having the
short arm actuated by a vertical reciprocating rod, moved through the
short proportional distance of this arm, which would give the length of
motion required by the long arm, connected to it above and working in
guides below having a stud roller on its lower end working in a cam
groove fixed on any part of the crank shaft or back of the crank, which
would give the required motion to the said rod and bell crank to turn
either end of the cylinder to the proper distance and at the proper time
in relation to the crank and motion of the piston. As by this arrange-
ment the rod and lever require to have the same rise and fall in relation
to the crank coming to and going from its dead centre, the cam may
be of a simple construction, as that of an annular groove for three-
fourths of the circle with the chord, or a very flat segmental curve
joining these having the drop at the centre required, and which is so
little graduated over the said fourth of the circumference left for it
that a good working cam action is obtained with not more than 1 to 3
of a gradient, also suitable for either the forward action or the reversing
or backing of the engines. The steam is admitted when the end cover
has stopped its inward motion, along with the piston, through the ports
entering the cylinder at these positive equal distances from both extreme
ends of the cylinder, made with valves to steam and cut-off and expand
to the said shortened end of the effective acting stroke of the piston,
otherwise as usual; a continuation of the port may be made in the
screwed part of the cylinder to allow of the escape of any steam which
may be confined between the ends of the cylinder and the piston after
passing the port, more than would equalize the pressure inside and out-
side of the end covers to prevent friction on the screw which sustains
the reacting pressure and consequent loss of power in working
these.
Although only one mode and means of fitting and moving the end
cover of the cylinder lias been described it will be evident to engineers
that various other mechanical equivalents or arrangements might be
adopted and used for the like purpose; as, by fitting and moving the
ends as block pistons to follow the real piston at the same speed with a
little clearance between them for the required distance before and after
the crank reaches and passes the dead centre, and moved direct by cams
or other equivalents from the crank shaft, or a countershaft driven at

page_text: the same speed. These ends or reacting block pistons might be locked
to sustain the pressure of the steam when they reach the limit of their
inward traverse by as many bolts, palls, or other equivalents as may be
desired, ranged round and carried either on the outer ends of the cylinder
or the pistons themselves simultaneously locked and unlocked by any
cam or other equivalent for the purpose worked from the crank shaft or
other moving part of the engine.
And in order that the nature, novelty, and mode of performing my
said Invention may be properly or fully understood I shall now proceed
to describe the several Figures on the Sheet of Drawings which I have
hereunto appended for that purpose, the same reference letters indicating
the same or equivalent parts in all the Figures where shown.
Figures 1 and 2 are a longitudinal vertical section and a corresponding
side clevation, and Figures 3 and 4 are a transverse section and a plan,
all respectively and corresponding to each other of the high-pressure
steam cylinder A and crank shaft C, with part of the supporting sole
plate Z and framing or side standards Z₁ of a vertical compound marine
engine constructed in accordance with, and illustrative of, one modifi-
cation of my said Invention or improvements sufficient to show the
nature, novelty, and mode of performing the same.
Referring to the modification or arrangement of mechanism for
performing my said Invention shown in Figures 1 to 4, A is the steam
cylinder carried on the framing Z, Z, with the ordinary piston B fitted
as usual on the piston rod B¹ jointed at its cross head B" to the upper
end of an ordinary connecting rod not shown in the Drawings, but
connected at its lower end to the crank C¹ of the crank shaft C, all so
that the piston B is reciprocated as usual through the full throw C, C, 1',
of the crank C', Figure 3, or corresponding stroke of the piston between
the dotted lines 1 1', in Figures 1 and 3. The cylinder A is made
longer than usual and fitted with a new movable pressure resisting
piston at each end, namely D and D', with short hollow piston rod Dч
working out through the stuffing boxes in the cover A' and lower end
A of the cylinder A; the ends of the piston rod B' work steam tight
through stuffing boxes in the outer ends of the tubular rods D11 of these
movable end pistons D, D¹, which are moved by their piston rods D
working out through stuffing boxes in the ends A¹, A", of the cylinder A
(as will be herein-after more fully explained) by the two slide bars D

page_text: and D³, crrried and reciprocated in guide brackets D' secured above and
below to the ends of the cylinder A, and having an angular part D*
working through slots in the outer part or end of the piston rods D¹¹¹.
In this case the cam E which moves the new end pistons D, D¹, is
keyed or otherwise fixed on one limb or elbow of the crank C¹ with cam
grooves E¹, E³, on the outer and inner face for working the upper and
lower pistons D, D¹, respectively as follows:-
A rocking lever F is fulcrumed at one end f to one of the side
standards Z³, so that the antifriction roller f' on a strong central pin in it
works into the upper side of the cam groove E, and has its outer free
end connected to the lower end of the connecting rod G, the upper end
of which is jointed to the short arm H of the rocking shaft I, which has
its long central arm or lever J coupled by the links and stud K to the
two upper slide bars D³, D*, so as to reciprocate them to and fro while
the roller f¹ is passing through the cam part E". In like manner the
rocking lever F is fulcrumed at one end on a stud f to the lower part of
the framing Z, so that its antifriction roller f¹ works into the cam
groove E on the inside of the cam E below, and has its outer end
jointed to the lower end of the connecting rod G' linked at top to the
short lever H¹ of the rocking shaft I¹, having its long central lever J¹
connected by the links and stud K³, all so as to reciprocate the two lower
slide bars D³ of the reacting piston D¹, while the antifriction roller of the
lever F¹ is passing through the cam part E³ of the back cam groove E²,
indicated by red dotted lines in Figure 3. The said reciprocation of the
duplex bars D2 and D³ (as indicated by the red segmental and radial lines
of the levers F and F', and the wipers H, J, and H', J', of the respective
wiper or rocking shafts I, I', Figure 3), and which takes place while the
antifriction rollers f¹ of the levers F and F¹ are passing through the cam
groove parts E", E³, of the cam E causes the pistons D¨and D¹ to travel
from their extreme inward positions (indicated. by the dotted lines
2---2 and 2'-2', and as shown in Figures 1 and 3) to their outmost
positions (indicated by the dotted lines 11 and 1'1"), and back
again to their inner position where they are shown in these Figures, all
along with or at the same rate as the piston B when it reaches the
position indicated by the lines 2 - - - 2 and 2¹ - 2¹, and while the crank
C¹ is passing through the upper or lower fourth or sixth of its revolution
near the dead centres C1, C1', (as indicated at C2, C1, C2, or C2¹, C1',
C2), where it has little power or leverage in turning the shaft C.

page_text: D-O
"
The extreme outward position of the antifriction rollers f¹ and their
levers F and F¹, and the inward position of the angled bars D³ and D³,
and their corresponding pistons D and D' at 2---2 and 2¹ 21, all as
shown in Figures 1 and 3, are given while the rollers flare passing
through the large concentric groove parts E' and E³ of the cam E, and
maintained stationary there while the piston B is travelling from 2 2
or 2¹2¹ to the end of its stroke and back again, and the crank O' is
passing or turning through the best or most direct acting parts of its
circle, as from C2 to C2 on the down stroke, and vice versa, from
21 to 22 and C2¹ to C2 on the up stroke, while the cam parts
E and E³ respectively carry the pistons D and D¹ out and in along with
or at the same rate as the piston B as it reaches near them alternately,
that is, while it is being forced to the extreme end of its stroke in cither
direction (as from 2---2 to 1-1 or from 21 21 to 1' - 11
respectively) by the full. expansion of the steam (when the crank C¹ is
passing from C2¹ to C2, or C2 to C2¹, in either direction to its upper or
lower dead centre C1 or C1¹), and while it is returning to the position
indicated at 2 2 or 2¹ 2' in Figures 1 and 2 as before stated.
2¹
The steam cylinder A is shown fitted with an ordinary slide valve ≈
within the steam chest z¹, and central exhaust port z", leading into the
exhaust space or casing round the cylinder A, leading to the steam
casing of the large or low pressure cylinder; but it will be understood
that these and the other parts of engines not affected by my said
improvements, or shown in the Drawings, may be constructed and
arranged in any other usual manner, except that the parts A² and A³ of
the inlet and outlet ports, where they enter the cylinder A, must be
formed so long and at such a distance from its ends as to allow room for
the traverse of the reacting pistons D and D', and the admission and exhaust
of the steam on their inner side when at their extreme traverse inwards
and outwards respectively. By these improvements the eccentrics and
valve are so set as to admit the steam by the ports A, or A³,
between the piston B and the pistons D or D¹, at the instant their
adjacent acting faces, with the slight clearance between them, have
reached the line 2 2 or 2¹ 2 on the down or up stroke of the
piston B respectively, and the piston D or D' has been brought to its
said stationary point 2 or 2¹ respectively, and is held there by its inclined
plane bars D or D³, which sustain all the pressure on the pistons D or D³,
so as to relieve the strain off the cam E and intermediate levers and
- 1>> ->

page_text: '
---
2 or 2¹.
rocking shafts I and I', which actuate these bars D' and D³, all while
the piston B is passing on to the extreme end of its stroke to the bottom
or top respectively, and back again to 2
2. The parts
and the arrows (as shown in the sectional view, Figure 1) indicate the
valve z as opening to admit the steam at the port A³ above the piston B,
and give its effective down stroke to the bottom, the exhaust taking place
all the time on the lower side of the piston B, and vice versa, the con-
verse taking place at and from the lower port A³ from the line 2¹--- 21
on the up stroke of the piston B; and to equalize the pressure on
both sides of the pistons D and D', while they are moving (along with
the piston B from and back to the lines 2 2 and 2¹
2¹ respec-
tively), the spaces d, d', of the cylinder A behind the pistons D, D¹, are
respectively connected with the ports A³ and As by the small pipes and
cocks a and a¹ (or it might be other equivalent valves) actuated auto-
matically by the lever, link, and stud a", a², a³, from the bars D2 and D³
of their respective pistons D and D¹, all so that as soon as either of these
begin to move it opens the cock a¹, or a¹¹, and allows the exhaust steam
to pass to the outside of the piston while it is moving, and so equalize
the pressure on both sides of the piston D or D', and close the cock a
or a again before they stop; and the high-pressure steam is again
admitted to the port A² or A³ for the next stroke of the piston B.
---y
Although the low-pressure cylinder of this compound engine is not
shown in the Drawings, it is to be understood that it also might be fitted
with the new or improved movable pistons D and D', all substantially
as described in reference to the high-pressure cylinder A shown, and that
the cylinder of any or all steam or other motion fluid reciprocating crank
rotating engines might be so fitted with these new or improved ends or
pistons, and their motive mechanism and connections arranged to act all
as and for the purposes therein described.
Figure 5 represents a geometrical diagram, in which the black lines
and figures represent the gross effect or effort throughout a single stroke
of the piston on the crank of an ordinary engine, admitting the steam at
the commencement of the stroke, while the red lines and figures.
represent the gross effect or effort throughout a single stroke of the same
piston on the crank, acting in accordance with my improvements,
admitting the steam (as shown in the Drawings) when the piston
has passed through a sixth of its stroke from either end, each taken on

page_text: their respective ordinates opposite the black and red figures for every
inch of the stroke.
Having now described the nature of my said Invention and the
manner of performing or carrying it into effect or practice, I would
observe in conclusion that what I consider novel and original and there-
fore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is, the construction of the cylinders of steam or
other motive fluid reciprocating crank rotative engines, with movable
ends or pistons arranged to act with their actuating mechanism and
connections, all substantially in the new or improved manner, and for the
purposes herein described, and shown in the accompanying Drawings, or
any mere modification thereof.
In witness whereof, I, the said Immer Fielden, have hereunto set
hand and seal, this Twenty-sixth day of June, in the year of
our Lord One thousand eight hundred and seventy-five.
my