IMPROVEMENTS IN STEAM ENGINES
Year: 1879

page_text: LETTERS PATENT to Francis Carr Marshall, of the Borough and County of
Newcastle on Tyne, Civil Engineer, for the Invention of "IMPROVEMENTS IN
STEAM ENGINES."
Sealed the 25th November 1879, and dated the 29th May 1879.
PROVISIONAL SPECIFICATION left by the said Francis Carr Marshall at the
Office of the Commissioners of Patents on the 29th May 1879.
FRANCIS CARR MARSHALL, of the Borough & County of Newcastle on Tyne,
Civil Engineer. "IMPROVEMENTS IN STEAM ENGINES."
The first part of this Invention relates to an improved form of cover for steam
cylinders. When it is intended to use this cover the cylinder terminates at the end
of the working barrel, a "spigot" being formed around the end. The cover is
made with a recess or cavity on that side joining the cylinder sufficiently large to
accomodate that portion of the piston working over the cylinder barrel with the.
requisite amount of clearance; and opposite the termination of the steam port in
the cylinder there is a continuation thereof in the cylinder cover brought to the,
back of the recess or cavity which receives the piston. The cover has a recess or
faucet" around the inside corresponding to the "spigot" on the cylinder. When
more convenient the "spigot" may be formed on the cover and a "faucet" bored
on the cylinder barrel to receive it.
"
The second part of this Invention relates to valves and valve gear in engines
requiring to be frequently reversed and to work at various grades of expansion.
In this arrangement the notion of the valve for either back or fore way is derived
from one excentric in a position virtually opposite the crank. This excentric is
embraced by straps in the usual way. To these the excentric rod, or what may be,
more appropriately called the valve lever, is attached, or it may form part of them.
This valve lever has in it two fixed pins, one at the end opposite the excentric and
the other at some point within its length, the exact position depending upon the
cut off of the valve. The end pin is caused to move in a circular are when the
engine is at work by a radius rod whose working centre is a pin in the end of
the reversing lever, the distances between the centres of the reversing lever and,
the radius rod being equal to and proportionate to the stroke of the excentric, the.,

page_text: length of the valve lever, and the relation between the length of the connecting rod
and the stroke of the engine, so as to make the cuts off at the opposite ends of the
cylinder equal to each other or differing from each other by an amount sufficient to
balance the working of the engine. The valve is worked from the intermediate
pin in the valve lever by means of a connecting rod attached to the valve spindle.
The whole gear is thus arranged:-The mean position of the valve lever is at right
angles to the valve spindle, and the centre of the reversing lever coincides with that
of the end pin in the valve lever when the engine is at each end of its stroke. The
engine is reversed from full gear foreway to full gear backway by moving the
reversing lever through an angle of about 40 degrees on each side of its centre
line, drawn at right angles to the mean position of the valve lever.
The valve used with this gear is made dissimilar ended, having in the case of a
valve with a single exhaust opening two steam openings at the end opposite or
virtually opposite the gear, and one steam opening only at the other end; and in
the case of a valve with double exhaust openings, three or four openings to steam
on that side opposite to the gear, and two only on the other side.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis Carr Marshall in the Great Seal Patent Office on the 29th
November 1879.
FRANCIS CARR MARSHALL, of the Borough and County of Newcastle-on Tyne,
Civil Engineer.
"IMPROVEMENTS IN STEAM ENGINES."
The first part of this Invention relates to an improved form of cover for steam
cylinders. When it is intended to use this cover the cylinder terminates at the
end of the working barrel, a "spigot" being formed around the end. The cover is
made with a recess or cavity on that side joining the cylinder, sufficiently large to
accommodate that portion of the piston working over the cylinder barrel, with the
requisite amount of clearance; and opposite to the termination of the steam port
in the cylinder there is a continuation thereof in the cover brought to the back of
"faucit
the recess or cavity which receives the piston. The cover has a recess or
around the inside corresponding to the "spigot" on the cylinder. When more con-
venient the "spigot" may be formed on the cover and the "faucit" bored on the
cylinder barrel to receive it.
"
When the working barrel is a separate liner this form of cover offers great
facilities for securing it in place and making perfect the joint at the two ends.
The second part of this Invention relates to valves and the gear for working
same in engines requiring to be frequently reversed and to work at various grades
of expansion. In this arrangement the motion of the valve for either way is
derived from one eccentric fixed upon the engine shaft in a position virtually
opposite to the crank; this eccentric is embraced by a strap in the usual way. To

page_text: this strap the eccentric rod, or what may be more appropriately called the valve
lever, is attached or may form part of it. This valve lever has on it two fixed pins,
one at the end opposite the eccentric and the other somewhere within its length,
the exact position depending upon the intended cut off of the valve. The end pin
is caused to move in a circular are when the engine is at work by a radius rod
whose working centre or "fulcrum" is a pin on the end of the reversing lever, the
respective distances between the working centres of the reversing lever and those
of the radius rod being equal and proportioned to the stroke of the eccentric, the
length of the valve lever, and the relation between the length of the engine con-
necting rod and the stroke of the piston, so as to make the cuts off at the opposite
ends of the cylinder equal to each other or differing from each other by an amount
sufficient to balance the working of the engine. The valve is worked from the
intermediate pin in the valve lever by means of a connecting rod attached to the
valve spindle. The whole gear (which is similar in principle to that known as
Haikworth's motion) is thus arranged. The mean position of the valve lever is at
right angles to the valve spindle, and the centre of the reversing lever coincides
with that of an are described by the end pin in the eccentric rod or valve lever
when the engine is at each end of its stroke. The engine is reversed from "full
gear" foreway to "full gear" backway by moving the reversing lever through an
angle of about forty degrees on each side of its centre line, drawn at right angles to
the mean position of the eccentric rod or valve lever. The valve used with this
gear is made dissimilar ended when connected direct to the eccentric rod or valve
lever, having in the case of a valve with a single exhaust opening two steam
openings at the end opposite or virtually opposite the gear, and one steam opening
at the other end or that next the gear, and in the case of a valve with double
exhaust openings three or four openings to steam on that end opposite to the gear,
and two only at the other end. By the introduction of intermediate levers a valve
of the ordinary similar ended kind may be used, the relative positions of the one
intermediate lever to which the valve is attached and of the other to which the
valve lever connecting rod is attached, and the arcs described by them, giving the
necessary equality of steam openings.
"
DESCRIPTION OF DRAWINGS.
In order that my Invention may be properly understood I now proceed to
describe the Figures and diagrams upon the Sheet of Drawings herewith.
Fig. 1 is an elevation of an arrangement of a vertical engine with the cylinder
in section to show the improved forin of cover. A is the cylinder cover; B, the
'spigot" turned on the end of the cylinder barrel, around and upon which the
cover is fitted; C is the steam port or passage brought up into the cover and
behind the bridge piece D, which is cast with it and makes the point of the
cylinder liner "E. In this arrangement the "liner" of working barrel of the
cylinder is held in place and kept tight at top and bottom by the cover.
"
Fig. 2 shews the application of the improved cover to a cylinder without a
separate liner.
Fig. 1 also shews the valve gear arranged to give equal steam openings by means
of a dissimilar ended valve. F is an eccentric fixed on the main shaft G of the
engine opposite the crank H; I is the eccentric rod or valve lever, one end of
which embraces the eccentric, the other is attached to a radius rod J, which
vibrates on a pin in the end of a lever K; L is the reversing weight shaft. The
engine is reversed by means of the worm M and sector N, or other suitable arrange-
ment either for hand or steam power. Motion is communicated to the valve Q
through the connecting rod O and the valve spindle P. The slide valve Q has two
steam edges at the top end and one only at the bottom end, thus giving a gross
steam opening at the top equal to that at the bottom, as the excess of vertical
upward motion of the valve over the "lap" is about double of that downward, as
will be seen from the orbit of the eccentric rod pin traced out at R.
Fig. 3 shows a plan of the gear above described.

page_text: Fig. 4 shews another means of compensating for this difference between the
upward and downward vertical motion when an ordinary similar ended valve is
used; F, I, J, O, P, and Q, indicate as before the eccentric, eccentric lever, radius
rod, valve connecting rod, valve spindle, and valve, respectively. The upper end
of the connecting rod O is attached to a lever 8 fixed on a rocking shaft T, on which
is fixed another lever U, from which the valve derives its motion. The relative
positions of these levers and the arcs described by them respectively are such that
the steam openings at the top and bottom are made equal to each other.
Fig. 5 is a diagram shewing a modification of the arrangement of Fig. 4, the
letters F, I, J, S, U, T, P, and Q, referring as before to the eccentric, eccentric lever,
radius rod, valve connecting rod, compensating levers and weight bar, valve spindle,
and valve respectively. In this modification the eccentric is fixed on the same side
of the shaft as the crank, and the radius rod on the opposite side of the eccentric
lever to that of the valve connecting rod.
Having now described the nature of my Invention and the manner in which it
may be carried into effect, though I do not confine myself to the details which I
have described, which may be varied to suit various forms of engines, I now
proceed to state what I consider novel in my said Invention, and therefore claim
as secured to me by the Letters Patent granted to me,-
First. The construction of cylinder covers substantially as shewn and described..
Second. The combination of mechanism by which the steam openings at the ends
of the cylinders are made equal to each other by a valve or valves having one or
more steam openings at the one end more than at the other, substantially as shewn
and described.
In witness whereof, I, the said Francis Carr Marshall, have hereunto set my
hand and seal, this Twenty eighth day of November, in the year of our
Lord One thousand eight hundred and seventy nine.
F. C. MARSHALL. (L.S.)

page_text: In the Matter of Letters Patent granted to FRANCIS CARR MARSHALL, of the
Borough and County of Newcastle-on-Tyne, Civil Engineer, for the
Invention of " IMPROVEMENTS IN STEAM ENGINES," bearing date the 29th
May, 1879, No. 2138.
TO ALL TO WHOM THESE PRESENTS SHALL COME,-
I, FRANCIS CARR MARSHALL, of the Borough and County of Newcastle-on-Tyne,
Civil Engineer, send greeting:
WHEREAS Her present Majesty Queen Victoria, by Her Letters Patent, under
the Great Seal of the United Kingdom of Great Britain and Ireland, bearing date
the 29th day of May 1879, in the forty second year of Her reign, did grant unto
me, my executors, administrators, and assigns, the sole privilege during the term
of fourteen years thence next ensuing to 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.
And whereas in pursuance of the conditions of the said Letters Patent I did on
the 29th November 1879, cause a Specification of the said Invention in writing
under my hand and seal to be filed in the Great Seal Patent Office:
And whereas since the filing of the said Specification I have discovered that the
first claim in the Specification of the said Letters Patent is of doubtful validity,
and I wish to avoid objections which may be made thereto; also I have discovered
certain clerical errors in the said Specification, whereby it is rendered deficient in
point of clearness:
NOW KNOW YE, that I the said Francis Carr Marshall do hereby for the
aforesaid reasons (by and with the leave of Her Majesty's Solicitor General) alter
and amend the said Specification in manner following, that is to say:-
On page 2 of the Specification as it is printed by Her Majesty's Printers. by
striking out lines 22 to 34 inclusive, commencing with "The first part of this," and
terminating with "at the two ends."
On page 2 by substituting "this" for the words "the second part of this" at the
commencement of line 35.
On page 3 by substituting "c" for "i" in the first word in line 15.
"
Also on page 3 by striking out in line 36 the words to shew the improved
form of cover.

page_text: opposite the gear, and one steam opening at the other end or that next the gear,
and in the case of a valve with double exhaust openings three or four openings
to steam on that end opposite to the gear, and two only at the other end. By the
introduction of intermediate levers a valve of the ordinary similar ended kind may
be used, the relative positions of the one intermediate lever to which the valve is
attached, and of the other to which the valve lever connecting rod is attached, and
the arcs described by them giving the necessary equality of steam openings.
DESCRIPTION OF DRAWINGS.
In order that my Invention may be properly understood I now proceed to
describe the figures and diagrams upon the Sheet of Drawings herewith.
Fig. 1 is an elevation of an arrangement of a vertical engine with the cylinder
in section. A is the cylinder cover; B,a "spigot" turned on the end of the cylinder
barrel, around and upon which the cover is fitted; C is the steam port or passage
brought up into the cover, and behind the bridge piece D, which is cast with it
and makes the joint of the cylinder "liner" E. In this arrangement (to which so
far no claim is made) the liner of working barrel of the cylinder is held in place
and kept tight at top and bottom by the cover.
The valve gear is shewn arranged to give equal steam openings by means of a
dissimilar ended valve; F is an eccentric fixed on the main shaft G of the engine
opposite the crank H; I is the eccentric rod or valve lever, one end of which
embraces the eccentric, the other is attached to a radius rod J which vibrates on a
pin in the end of a lever K; L is the reversing weight shaft. The engine is
reversed by means of the worm M and sector N, or other suitable arrangement,
either for hand or steam power. Motion is communicated to the valve Q through
the connecting rod O and the valve spindle P. The slide valve Q has two steam
edges at the top end and one only at the bottom end, thus giving a gross steam
opening at the top equal to that at the bottom, as the excess of vertical upward
motion of the valve over the "lap" is about double of that downward, as will be
seen from the orbit of the eccentric rod pin traced out at R.
Fig. 3 shews a plan of the gear above described.
Fig. 4 shews another means of compensating for this difference between the
upward and downward vertical motion when an ordinary similar ended valve is
used; F, I, J, O, P, and Q indicate, as before, the eccentric, eccentric lever, radius
rod, valve connecting rod, valve spindle, and valve respectively. The upper end of
the connecting rod is attached to a lever S fixed on a rocking shaft T, on which
is fixed another lever U from which the valve derives its motion. The relative
positions of these levers and the arcs described by them respectively are such
that the steam openings at the top and bottom are made equal to each other.
Fig. 5 is a diagram shewing a modification of the arrangement of Fig. 4, the
letters F, I, J, O, S, U, T, P. and Q, referring as before to the eccentric, eccentric
lever, radius rod, valve connecting rod, compensating levers and weight bar, valve
spindle and valve respectively. In this modification the eccentric is fixed on the
same side of the shaft as the crank, and the radius rod on the opposite side of the
eccentric lever to that of the valve connecting rod.
Having now described the nature of my Invention, and the manner in which it
may be carried into effect, it is to be noted that no claim is made to the construction
of cylinder covers as shewn and described, and though I do not confinemyself to
the details which I have described, which may be varied to suit various forms of
engines, I now proceed to state what I consider novel in my said Invention
and therefore claim as secured to me by the Letters Patent granted to me,
namely,
The combination of mechanism by which the steam openings at the ends of the
cylinder are made equal to each other by a valve or valves, having one or more

page_text: steam openings at the one end more than at the other, substantially as shewn and
described.
In witness whereof, I, the said Francis Carr Marshall, have hereunto set my
hand and seal, this Thirty first day of August, in the year of our Lord One
thousand eight hundred and eighty.
I hereby grant my fiat, giving leave to the within named Francis Carr Marshall
to file in the Great Seal Patent Office, with the Specification to which the same
relates, the above written Disclaimer and Memorandum of Alteration.
Dated this Thirtieth day of September, A.D. 1880).

page_text: In the Matter of Letters Patent granted to FRANCIS CARR MARSHALL, of the
Borough and County of Newcastle-on-Tyne, Civil Engineer, for the
Invention of "IMPROVEMENTS IN STEAM ENGINES," bearing date the 29th
May, 1879, No. 2138.
TO ALL TO WHOM THESE PRESENTS SHALL COME,-
I, FRANCIS CARR MARSHALL, of the Borough and County of Newcastic-on-Tyne,
Civil Engineer, send greeting:
WHEREAS Her present Majesty Queen Victoria, by Her Letters Patent, under
the Great Seal of the United Kingdom of Great Britain and Ireland, bearing date
the 29th day of May 1879, in the forty second year of Her reign, did grant unto
me, my executors, administrators, and assigns, the sole privilege during the term
of fourteen years thence next ensuing to 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.
And whereas in pursuance of the conditions of the said Letters Patent I did on
the 29th November 1879, cause a Specification of the said Invention in writing
under my hand and seal to be filed in the Great Seal Patent Office:
And whereas since the filing of the said Specification I have discovered that the
first claim in the Specification of the said Letters Patent is of doubtful validity,
and I wish to avoid objections which may be made thereto; also I have discovered
certain clerical errors in the said Specification, whereby it is rendered deficient in
point of clearness:
NOW KNOW YE, that I the said Francis Carr Marshall do hereby for the
aforesaid reasons (by and with the leave of Her Majesty's Solicitor General) alter
and amend the said Specification in manner following, that is to say:-
On page 2 of the Specification as it is printed by Her Majesty's Printers, by
striking out lines 22 to 34 inclusive, commencing with "The first part of this," and
terminating with "at the two ends."
On page 2 by substituting "this" for the words "the second part of this " at the
commencement of line 35.
On page 3 by substituting "c" for "i" in the first word in line 15.
Also on page 3 by striking out in line 36 the words "to shew the improved
form of cover."

page_text: " a
" for "the."
Also on page 3 at the end of line 36 (after "B") by substituting
Also on page 3 in line 40 after the word "arrangement" by inserting “(to
which so far no claim is made.) "
Also on page 3 by striking out lines 42 and 43 commencing with "Fig. 2" and
terminating with "liner."
*1
Also on page 3 at the commencement of line 44 by substituting "The" for
Fig. 1 also shews the."
21
Also in the same line after "gear" by inserting the words "is shewn."
On page 4, line 10, by inserting "O" between "J" and "S."
effect" and the word
Also on page 4, line 16, by inserting between the word
though" the words "it is to be noted that no claim is made to the construction
of cylinder covers, as shewn and described, and."
$
.
Also on page 4, line 19, by inserting the word "namely" after the words
"granted to me.
"
Also on the same page by striking out the whole of line 20, being the first
claiming clause.
Also on the same page, line 21, by striking out the word "Second" at the
coinmencement of the line.
And in order that the effect of this Disclaimer may be better understood the
following copy of the Specification as it will appear when such Disclaimer has
been made as aforesaid is appended, videlicet.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis Carr Marshall in the Great Seal Patent Office on the 29th
November 1879.
FRANCIS CARR MARSHALL, of the Borough and County of Newcastle-on-Tyne,
Civil Engineer.
"IMPROVEMENTS IN STEAM ENGINES."
"
This Invention relates to valves and the gear for working same in engines requiring
to be frequently reversed and to work at various grades of expansion. In this
arrangement the motion of the valve for either way is derived from one eccentric fixed
upon the engine shaft in a position virtually opposite to the crank; this eccentric is
embraced by a strap in the usual way. To this strap the eccentric rod, or what may
be more appropriately called the valve lever, is attached, or may form part of it.
This valve lever has on it two fixed pins, one at the end opposite the eccentric, and
the other somewhere within its length, the exact position depending upon the
intended cut off of the valve. The end pin is caused to move in a circular arc
when the engine is at work by a radius rod, whose working centre or "fulcrum
is a pin on the end of the reversing lever, the respective distances between the
working centres of the reversing lever and those of the radius rod being equal and
proportioned to the stroke of the eccentric the length of the valve lever, and the
relation between the length of the engine connecting rod and the stroke of the
piston, so as to make the cuts off at the opposite ends of the cylinder equal to each
other, or differing from each other by an amount sufficient to balance the working
of the engine. The valve is worked from the intermediate pin in the valve lever
by means of a connecting rod attached to the valve spindle. The whole gear
(which is similar in principle to that known as Hackworth's motion) is thus
arranged. The mean position of the valve lever is at right angles to the valve
spindle, and the centre of the reversing lever coincides with that of an are described
by the end pin in the eccentric rod or valve lever when the engine is at each end of
its stroke. The engine is reversed from "full gear" foreway to "full gear" back-
way by moving the reversing lever through an angle of about forty degrees on each
side of its centre line drawn at right angles to the mean position of the eccentric
rod or valve lever. The valve used with this gear is made dissimilar, ended when
connected direct to the eccentric rod or valve lever, having in the case of a valvo

page_text: on at end opposite to the gear, and two only at the other end.
By the
introduction of intermediate levers a valve of the ordinary similar ended kind may
be used, the relative positions of the one intermediate lever to which the valve is
attached, and of the other to which the valve lever connecting rod is attached, and
the arcs described by them giving the necessary equality of steam openings.
DESCRIPTION OF DRAWINGS.
In order that my Invention may be properly understood I now proceed to
describe the figures and diagrams upon the Sheet of Drawings herewith.
Fig. 1 is an elevation of an arrangement of a vertical engine with the cylinder
in section. A is the cylinder cover; B, a " spigot" turned on the end of the cylinder
barrel, around and upon which the cover is fitted; C is the steam port or passage
brought up into the cover, and behind the bridge piece D, which is cast with it
and makes the joint of the cylinder "liner" E. In this arrangement (to which so
far no claim is made) the "liner" of working barrel of the cylinder is held in place.
and kept tight at top and bottom by the cover.
The valve gear is shewn arranged to give equal steam openings by means of a
dissimilar ended valve; F is an eccentric fixed on the main shaft G of the engine
opposite the crank H; I is the eccentric rod or valve lever, one end of which
embraces the eccentric, the other is attached to a radius rod J which vibrates on a
pin in the end of a lever K; L is the reversing weight shaft. The engine is
reversed by means of the worm M and sector N, or other suitable arrangement,
either for hand or steam power. Motion is communicated to the valve Q through
the connecting rod O and the valve spindle P. The slide valve Q has two steam
edges at the top end and one only at the bottom end, thus giving a gross steam
opening at the top equal to that at the bottom, as the excess of vertical upward
motion of the valve over the "lap" is about double of that downward, as will be
seen from the orbit of the eccentric rod pin traced out at R.
Fig. 3 shews a plan of the gear above described.
Fig. 4 shews another means of compensating for this difference between the
upward and downward vertical motion when an ordinary similar ended valve is
used; F, I, J, O, P, and Q indicate, as before, the eccentric, eccentric lever, radius
rod, valve connecting rod, valve spindle, and valve respectively. The upper end of
the connecting rod O is attached to a lever S fixed on a rocking shaft T, on which
is fixed another lever U from which the valve derives its motion. The relative
positions of these levers and the arcs described by them respectively are such
that the steam openings at the top and bottom are made equal to each other.
Fig. 5 is a diagram shewing a modification of the arrangement of Fig. 4, the
letters F, I, J, O, S, U, T, P, and Q, referring as before to the eccentric, eccentric
lever, radius rod, valve connecting rod, compensating levers and weight bar, valve
spindle and valve respectively. In this modification the eccentric is fixed on the
same side of the shaft as the crank, and the radius rod on the opposite side of the
eccentric lever to that of the valve connecting rod.
Having now described the nature of my Invention, and the manner in which it
may be carried into effect, it is to be noted that no claim is made to the construction
of cylinder covers as shewn and described, and though I do not confine myself to
the details which I have described, which may be varied to suit various forms of
engines, I now proceed to state what I consider novel in my said Invention
and therefore claim as secured to me by the Letters Patent granted to me,
namely,
The combination of mechanism by which the steam openings at the ends of the
cylinder are made equal to each other by a valve or valves, having one or more

page_text: steam openings at the one end more than at the other, substantially as shewn and
described.
In witness whereof, I, the said Francis Carr Marshall, have hereunto set my
hand and seal, this Thirty first day of August, in the year of our Lord One
thousand eight hundred and eighty.
TATT
To the Commissioners of Patents for Inventions.
I hereby grant my fiat, giving leave to the within named Francis Carr Marshal
to file in the Great Seal Patent Office, with the Specification to which the same
relates; the above written Disclaimer and Memorandum of Alteration.
Dated this Thirtieth day of September, A.D. 1880.
FARRER HERSCHELL,