IMPROVEMENTS IN STEAM ENGINES
Year: 1859

page_text: LETTERS PATENT to Charles Sells, of Stockwell, in the County of Surrey,
Engineer, for the Invention of "IMPROVEMENTS IN STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Charles Sells at the
Office of the Commissioners of Patents, with his Petition, on the 28th
November 1859.
I, CHARLES SELLS, of Stockwell, in the County of Surrey, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN STEAM
ENGINES," to be as follows:-
These improvements are applicable more particularly to steam engines in-
tended to work with a great degree of expansion of the steam in the cylinder,
and consist in an improved method of imparting a variable motion to the slide
valve, so that the time of cutting off the steam may be regulated as required
without materially altering the time of admitting the steam into or allowing it
to escape from the cylinder. This is effected by using an apparatus worked
by eccentrics, or other means, to give the link ordinarily used in connection
with double eccentrics a motion up or down, or in the direction of its length,
so as to move the sliding block forward and close the steam ports at the time
required, and then return the link to its original position before opening the
ports again for the admission of the steam. By these means any degree of
expansion may be used with the ordinary slide valve, without the employment
of another valve for that purpose, while at the same time the steam will be cut
off much closer to the cylinder, and thereby a greater economy of fuel will be
effected.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Sells in the Great Seal Patent Office on the 28th
May 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
SELLS, of Stockwell, in the County of Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent bearing date the Twenty-eighth day of November, in the year of our
Lord One thousand eight hundred and fifty-nine, in the Twenty-third year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
*the said Charles Sells, Her special licence that I, the said Charles Sells, my
executors, administrators and assigns, or such others as I,.the said Charles Sells,
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 con-
dition (amongst others) that I the said Charles Sells, my executors or admi-
nistrators, 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 Charles Sells, do hereby declare the
nature of my said Invention, and in what manuer the same is to be performed;
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 :--
These improvements are applicable more particularly to steam engines
intended to work with a great degree of expansion of the steam in the cylinder,
and consist in an improved method of imparting a variable motion to the slide
valve, so that the time of cutting off the steam may be regulated as required
without materially altering the time of admitting the steam into or allowing it
to escape from the cylinder.
My Invention consists in the employment of an apparatus worked from the
crank shaft of the engine by eccentrics or other convenient means to give
motion to the link (used for working the slide valve in connection with double
eccentrics) in the direction of its length, so as to cause it to quicken the
motion of the valve at the time of shutting off the steam, and then cause the
valve to move slower than its ordinary rate, so as to shut off the steam at any

page_text: part of the stroke that may be required without altering the time of opening
the ports for its admission into or for its escape from the cylinder, or
vicê versa, the motion may be given to the sliding block in order to effect
the same object. By these means the additional expansion valve ordinarily
used may be dispensed with, while at the same time the steam will be shut
off much closer to the cylinder, and thereby a greater economy of fuel
effected, (which will be particularly the case in quick working engines, and in
oscillating engines, which ordinarily have long belt passages between the
expansion and slide valves) as the slide jackets and passages will not be cooled
by the steam being expanded down to low temperature in them.
In the Drawings hereunto annexed I have illustrated the manner in which
I carry my Invention into effect, but I do not confine myself to the particular
arrangement shown, as it will require to be varied to suit the description of
engine to which it may be applied.
Figure 1 shows a side elevation, and Figure 2 an end view of the apparatus
applied to a horizontal marine engine, with so much of the engine shown as
will render the nature and action of the apparatus clearly seen and understood.
The same letters of reference indicate like parts in both Figures. A is the link
with its sliding block B giving motion to the slide crosshead C. D, D, are the
two eccentrics and rods (one for the forward and one for the backward motion)
fixed on the crank shaft E. F is an additional eccentric which gives motion
by its rod to the lever G on the cross shaft H. This lever has a sliding block
moving in a slot, and which is adjusted by the screw and hand wheel I. On
the end of the cross shaft H is another lever K which vibrates equally on each
side of its position as shown in the Drawing, so as to raise and lower the
link A by means of the counterbalance lever L twice during each revolution of
the engine. It will be readily seen that supposing the sliding block B to be
moving in the direction shown by the arrow for shutting off the steam and the
link is then raised, the link will by its inclined action cause the block B, and
consequently the slide valve, to move more rapidly in the direction indicated
than it would do if actuated by its eccentric alone, and so shut off the steam
sooner, and then if it be lowered again into its former position it will cause the
slide to move slower than its ordinary rate so as only to open the ports for
the admission of the steam at the proper time.
To obtain the best result I find the eccentric F should be fixed on the crank
shaft so that the lever K. may be in the centre of its travel as shown in the
Drawing, when the crank is within about 10° of passing over its dead centre,
or just before the piston arrives at the end of its stroke, and when so fixed the
steam may
be cut off at any point from to of the stroke of the piston

page_text: without affecting the time of admitting the steam, or of allowing it to escape
from the cylinder. The amount of expansion is regulated by the hand wheel
and screw I, which adjusts the position of the sliding block in the lever G so
as to give a greater or less amount of lifting motion to the link, giving it
more motion when required to work with a greater amount of expansion, or
less when working with a less amount.
In the Drawing I have shown how the apparatus may be combined with the
ordinary starting and reversing gear; the lever G is shown working loose on the
cross shaft H, and the clutch M. is made to slide on feathers or keys, and may
be thrown into gear either with the lever G or with the worm wheel N, which
is also fitted loose on the cross shaft, and which is worked by the starting
wheel O in the ordinary way. The worm wheel N may be made so as to allow
the clutch M to slide into gear with it in almost every position, while the lever
G must be made so that the clutch will slide into gear with it in one relative
position only. On starting the engines the clutch must be in gear with the
worm wheel N, and if required to work expansively, it must be thrown out of
gear with it and into gear with the expansion lever G; and when again
required to stop or reverse the engines, the clutch must be thrown out of gear
with the expansion lever, and into gear with the worm wheel, when the link
may be raised by the hand wheel O in the ordinary way.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I have described what I
consider the most simple form of apparatus for effecting the object of my
Invention, and the manner in which it operates; but I do not confine myself
to the exact arrangement of apparatus shown in the Drawing; but what I
claim is, the application of apparatus for imparting motion (in the direction of
its length) to the link ordinarily used with double eccentrics, or vice versa, to
the sliding block, for the purpose of cutting off the steam by the slide valve at
any part of the stroke required, without altering the time of its admission,
essentially as herein-before described.
In witness whereof, I, the said Charles Sells, have hereunto set my
hand and seal, this Twenty-fourth day of May, One thousand eight
hundred and sixty.
CHARLES SELLS. (L.S.)