IMPROVEMENTS IN CONTINUOUS EXPANSION ENGINES AND IN THE VALVES TO BE USED THEREWITH OR WITH ORDINARY ENGINES
Year: 1868

page_text: LETTERS PATENT to John Stewart and John Nicholson, both of
Poplar, in the County of Middlesex, Engineers, for the Invention
of "IMPROVEMENTS IN CONTINUOUS EXPANSION ENGINES AND IN THE VALVES
TO BE USED THEREWITH OR WITH ORDINARY ENGINES."
Sealed the 20th January 1869, and dated the 8th September 1868.
PROVISIONAL SPECIFICATION left by the said John Stewart and John
Nicholson at the Office of the Commissioners of Patents, with their
Petition, on the 8th September 1868.
We, JOHN STEWART and JOHN NICHOLSON, both of Poplar, in the
County of Middlesex, Engineers, do hereby declare the nature of our said
Invention for "IMPROVEMENTS IN CONTINUOUS EXPANSION ENGINES AND IN
THE VALVES TO BE USED THEREWITH OR WITH ORDINARY ENGINES," to be as
follows:-
Our Invention has for its object to economise the working of the steam
to the greatest extent practicable, and to produce an uniformity of motion
that has not hitherto been attainable by any other plan of working steam.
By our improved plan herein described all the useful effect can be got

page_text: out of the steam minus the useless resistances, and by working two of
these engines with the cranks set at right angles a very near approach
to uniformity of motion will be attained, a point of the highest
importance for the durability and safe working of engines:
In carrying this Invention into effect two or more cylinders are so
arranged that their pistons act in unison, the steam acting upon them in
the propelling direction until the whole of its useful effect is expended in
the production of power or energy. No expansion gear is necessary nor
is the steam used twice over, but acts at the same time on each piston in
the same direction. By the use of the retaining valve herein-after
described between the exhaust and the condenser, or between the exhaust
and the atmosphere, according to the form of engine employed, the com-
pression may be regulated to any required degree. The steam can be
worked to any range of expansion, and the power of this class of engines
can be doubled instantaneously, a great advantage for war vessels in case
of attack, and for all vessels in danger from collision or other cause. The
manner of using steam in continuous expansion engines is at once the
most simple and natural and also the most inexpensive, the saving of fuel
being very great.
In the Drawing accompanying this Provisional Specification for the
purpose of showing the manner in which the Invention is carried into
effect, A is the cylinder receiving its steam from the boiler; B is an
expansion cylinder into which the steam passes from the cylinder A,
which receives its steam from the boiler directly the piston therein
(in A) has passed in its up or down stroke the passages C and D in the
side of cylinder A. Each of these ports or passages may be described
as of a perforated cellular construction with passages of somewhat of a.
zig-zag form. The cranks upon the shaft to which the piston rods are
connected are set at right angles, which allows the piston to occupy the
respective or relative positions shown in the Drawing. E, F, arc slides
worked by eccentrics for the entrance and exit of the steam to and from
the cylinder; G is a slide also worked by an eccentric within the nozzle
or casing H, which is so constructed as to retain the steam from the
exhaust port until it has been used to any desired or determined.degree
before the stroke of the first cylinder A is ended, or at any point of the
return stroke that may be determined as necessary for the most economical
working of the engines. The. hollow valve may be termed a travelling
steam chest; it is enveloped; the steam enters into the centre, and a

page_text: ring is inserted in the orifice. The improvement in the packing ring
is that the ring is made self-acting by the steam acting on the under
side of the ring, and it presses it against the steam chest cover. It
is an equilibrium valve, and can. be applied to any class of engine in
ordinary use.
SPECIFICATION in pursuance of the conditions of the Letters Patent;.
filed by the said John Stewart and John Nicholson in the Great.
Seal Patent Office on the 6th March 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
STEWART and JOHN NICHOLSON, both of Poplar, in the County of
Middlesex, Engincers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her-
Letters Patent, bearing date the Eighth day of September, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give-
and grant unto us, the said John Stewart and John Nicholson, Her
special licence that we, the said John Stewart and John Nicholson, our
executors, administrators, and assigns, or such others as we, the said
John Stewart and John Nicholson, our exccutors, 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 "IMPROEMENTS IN. CONTINUOUS EXPANSION
ENGINES AND IN THE VALVES TO BE USED THEREWITH OR WITH ORDINARY ENGINES,"
upon the condition (amongst others) that we, the said John, Stewart.
and John Nicholson, our executors or administrators, by an instru-
ment in writing under our, or one of our 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 we, the said John Stewart and John Nicholson...

page_text: the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This Invention has for its object to economise the working of the
steam to the greatest extent practicable, and to produce an uniformity of
motion that has not hitherto been attainable by any other plan of
working steam. By our improved plan herein-after described all the
useful effect can be got out of the steam minus the useless resistances,
and by working two of these engines with their cranks set at right angles
a very near approach to uniformity of motion will be attained, a point of
the highest importance for the durability and safe working of the
engines.
In carrying this Invention into effect two or more cylinders are so
arranged that their pistons act in unison, the steam acting upon them
in the propelling direction until the whole of its useful effect is, expended
in the production of power or energy. No expansion gear is necessary
nor is the steam used twice over, but acts at the same time on each piston
and in the same direction. By the use of the retaining valve herein-
after described between the exhaust and the condenser, or between the
exhaust and the atmosphere, according to the form of engine employed,
the compression may be regulated to any required degree. The steam
can be worked to any range of expansion, and the power of engines con-
structed according to this. Invention can be doubled instantaneously, a
great advantage for war vessels in case of attack, and for all vessels in
danger from collision or other cause. The manner of using steam in
continuous, expansion engines is, at once the most simple and natural and
also the most inexpensive, the saving of fuel being very great. In the
construction of large engines we prefer to use three cylinders.
In order that the nature of this Invention and the means by which the
same is effected may be clearly described and ascertained, this Specifi-
cation is accompanied by a Sheet of Drawings, having letters of reference
marked thereupon.
In these Drawings our Invention is shown as applied to two cylinders.
A (Figure 1) is the cylinder receiving steam from the boiler; B is an
expansion, cylinder, into which the steam passes from the cylinder A,
which receives its steam from the boiler directly the piston therein (in A)
has passed in its up or down stroke the ports C and D. in the side of
cylinder A. Each of the ports may be described as of a perforated or
cellular construction with passages, by proference of somewhat of a

page_text: zig-zag form; the object of this is to facilitate the working of the piston
in passing the ports. The number of subdivisions, cells, or passages,.
which may be of any form or shape, may be regulated in accordance
with the size of cylinder; these ports C, D, arc set as far from the centre
as the versed line of the connecting rod. The cranks upon the shaft to
which the piston rods are connected are set at right angles, which allows
the pistons to occupy the respective or relative positions shown in the
Drawing. E, F, are slides worked by eccentrics for the entrance and
exit of the steam to and from the cylinders; G is a slide also worked by
an eccentric within the nozzle or casing H. G and H are so constructed
as to retain the steam from the exhaust port until it has been used to any
desired or determined degree before the stroke of the first cylinder is
ended, or at any point of the return stroke that may be determined upon
as necessary for the most economical working of the engines. It will
be understood that this regulating or retaining valve G, H, is generally
placed between the exhaust port and the condenser or the atmosphere,
according to the form of engine in which it is employed, or it may be
applied to any part of the cylinder for the purpose of retaining the steam
that has worked the piston the up and down stroke; the hollow valve F
may be termed a travelling steam chest; it is enveloped. The steam
enters into the centre and a ring is inserted in the orifice; the improve-
ment in the packing ring is that the ring is made self-acting by the
steam acting on the under side of the ring and it presses the ring against
the steam chest cover. It is an equilibrium valve, and can be applied to.
every class, of engine in ordinary use..
We propose to apply this Invention to existing double cylinder engines
by the removal of one cylinder and the substitution therefor of our smaller.
cylinder A with the ports C, D, and the hollow valve F. We also
purpose applying in this case the retaining valve G, H; or in the case of
three cylinder engines we substitute our cylinder A for one of these.
cylinders, placing the same in any position convenient for the purpose.
The indicator Diagrams show the action of the steam for one-half the
stroke, the Diagram A¹ illustrating the action of steam in cylinder A, and
the Diagram B' showing the action of steam in cylinder B.
It will be observed that the Drawings refer merely to those parts of
the engines to which our Invention is applied. As we do not claim
other than the improvements illustrated or described other parts have not

page_text: been shown, and may be varied according to purpose for which the
engine is applied.
Having now particularly described and ascertained the nature of our
Invention, and the manner in which the same is to be performed, we
wish it to be clearly understood that what we claim is,―
I. The use of perforated or cellular ports in the side of the cylinder
that receives the steam from the boiler, these ports being set as far from
the centre as the versed line of the connecting rod.
II. The use of a hollow self-acting valve which may be termed a
travelling steam chest.
III. The use of the regulating or retaining valve connected with the
exhaust port and interposed between it and the condenser or the
atmosphere, according to the form of engine used.
IV. Or the application of the said valve to any part of the cylinder for
retaining the steam that has worked the piston the up and down stroke.
In witness whereof, I, the said John Nicholson, on behalf of
myself and of the said John Stewart, have hereunto set 'my hand
and seal, this Sixth day of March, in the year of our Lord One
thousand eight hundred and sixty-nine.