CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1842

page_text: J. AND E. VARLEYS
TION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
VARLEY, of Colne, in the County of Lancaster, Engineer, and EDMONDSON
VARLEY, of the same place, Cotton Manufacturer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-eighth day of April, in the fifth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto us, the said John
Varley and Edmondson Varley, Her especial licence, full power, sole privilege
and authority, that we, the said John Varley and Edmondson Varley, our
executors, administrators, and assigns, and such others as we, the said John
Varley and Edmondson Varley, our executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England and Wales and the Town of
Berwick-upon-Tweed, our Invention of "CERTAIN IMPROVEMENTS IN STEAM
ENGINES;" in which said Letters Patent is contained a proviso that we,
the said John Varley and Edmondson Varley, or one of us, shall cause a
particular description of the nature of our said Invention, and in what
manner the same is to be performed, to be enrolled in Her Majesty's High
Court of Chancery within six calendar months next and immediately after the
date of the said in part recited Letters Patent, as in and by the same, reference
being thereunto had, will more fully and at large appear.

page_text: ..JW KNOW YE, that in compliance with the said proviso, I, the said
Edmondson Varley, on behalf of myself and of the said John Varley, do hereby
declare that the nature of the said Invention, and the manner in which the
same is to be performed, is particularly described and ascertained in and by the
Drawings hereto annexed, and the following explanation thereof; that is to
say:
Our improvements in steam engines consist in the application and employ-
ment of certain novel mechanism or apparatus to be substituted in place of the
ordinary excentrics or cranks, commonly attached to or used in connection
with the main or crank shaft of steam engines, for the purpose of working the
D or other slide valves to regulate the admission and exit of steam to and from
the cylinders. The object or intention of our improvements is to enable the
steam employed in working steam engines to be worked expansively and
compressively, and thus to economize the consumption of fuel, and also to effect
an increase of power by the introduction-or application of a simple arrange-
ment of apparatus or mechanism, which shall cause the steam to be quickly
admitted to the cylinder, and cut off therefrom at any required angle of the
crank during its revolution, by means of the suitable action of such apparatus
upon the ordinary D or other slide valves commonly used for.regulating the
admission of steam to the cylinder of the engines. In order that our improve-
ments in steam engines may be perfectly understood, we have attached to these
presents a sheet of Drawings representing their application to an ordinary con-
densing steam engine, which will sufficiently illustrate their mode of operation
and effect to the practical engineer or mechanician.
Fig. 1 represents an elevation of a condensing steam engine, with our im-
provements represented attached thereto, being those parts shaded with colour.
Fig. 2 is a view of the same, drawn, detached, and, upon a large scale; and
Fig. 3 is a detached view of. a similar apparatus, exhibiting, some slight modi-
fication in the application thereof.. Similar letters of reference point out cor-
responding parts in all the Figures. a is the main or crank shaft of the steam
engine; b, c, is a tappet or tumbler fixed upon the crank shaft, and substituted
in place of the ordinary excentric; d, e, is a cam substituted in place of the
ring surrounding the ordinary excentric. To the cam d, e, horizontal slides
ff, are attached or made in one piece with the cam, having V edges or slides,
and sliding to and fro in brasses or steps, mounted in the pillars or standards
9, 9. The cam d, e, may be attached to the ordinary excentric rod or slide rod,
valve rod h, h, by means of bolts and nuts, as in common, and shewn in Fig.
2, or by being jointed to the end of the sliding piece f, as shewn in Fig. 3.
It will thus be instantly evident to persons acquainted with the steam engine

page_text: that as the crank shaft a revolves in the direction of the arrow the first rise or
lift 6 upon the tappet or tumbler will act against the surface d upon the interior
of the cam, and thus shift the cam, and with it the excentric rod h, h, into the
position of the dotted red lines in Fig. 3, and consequently effect the cutting
off the steam in the slide valves at the quarter stroke (or any other given point),
and that, as the tappet continues the revolution, the second or extreme rise c
upon the tappet will now act upon the surface d, and shift the cam, and with
it the excentric rod, and consequently open the slide valve port to the full extent
for the admission of steam, as drawn in red lines in Fig. 3. The completion
of the revolution of the crank shaft will cause the double tappet b, c, to act
upon the other surface, e, of the cam, and consequently reverse the action of
the valves. Thus it will be understood that by this apparatus the valves re-
ceive a double or interrupted motion instead of the regular motion caused by
the ordinary eccentrics, namely, two strokes for opening the ports of the slide
valves into the cylinder, and two for closing the same at each revolution of the
crank shaft. The first stroke of the upper tappet closes the induction port,
shuts off the steam, and causes that which is confined in the cylinder to work
expansively, leaving the eduction port partially open until the piston has moved
a little farther, when the eduction port becomes closed, and the steam which
remains uncondensed in the cylinder becomes compressed therein, nearly to the
extremity of the stroke of the piston, or until the second stroke of the tappet
opens the contrary induction port, at which time the compressed steam in the
cylinder and newly-admitted steam meet together, and form a counterbalance and
reaction in the return stroke of the piston, the eduction port being opened a little
prior to the induction port. It will be seen that these two strokes of the tappet
take place in one half of a revolution of the main or crank shaft and are again
repeated in the other half of the revolution, admitting and cutting off the
steam at any required angle of the crank in each entire revolution. It will
be seen in Fig. 3 that the double tappet or tumbler b, c, may be (if pre-
ferred) made in two parts, for the purpose of regulating any adjustment of
the striking points required; and it will also be evident to the practical
mechanic that the double tappet or tumbler may also be applied to any shaft
employed for the purpose of communicating motion to the slide valves.
Having now described the nature of our said Invention, and the manner in
which the same is to be performed, we desire it to be understood, that we are
are aware that many variations of the construction and mode of application of
our improvements may be made. We therefore claim distinctly, the substi-
tution and employment of a double tappet or tumbler in connection with the
internal cam and excentric or valve rod (instead of the ordinary excentric

page_text: motion) for the purpose of working the D or slide valves, in order that
engines so constructed may be enabled to work the steam expansively and
compressively.
In witness whereof, I, the said Edmondson Varley, have hereunto put my
hand and seal, this Twenty-fifth day of October, in the year of our Lord &
One thousand eight hundred and forty-two.
Inrolled the Twenty-eighth day of October, in the year above written.