CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1841

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
SIMS, of Redruth, in the County of Cornwall, Engineer, 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-ninth day of April, in the fourth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said James
Sims, Her especial licence, full power, sole privilege and authority, that I,
the said James Sims, my exors, adñors, and assigns, and such others as I, the
said James Sims, my exors, adññiors, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the term
of years therein expressed, should and lawfully might make, use, exercise, and
vend, within that part of Her Majesty's United Kingdom of Great Britain and
Ireland called England, Her Dominion of Wales, and the Town of Berwick-
upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS IN STEAM ENGINES;" in
which said Letters Patent there is contained a proviso that I, the said James
Sims, shall cause a particular description of the nature of my said Invention,
and the manner in which the same is to be performed, to be inrolled 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
annear

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
James Sims, do hereby declare that the nature of my said invented improvements
consists in a new method of constructing and working steam engines, whereby
equal quantities of steam do a greater amount of duty than has by the like
quantities been heretofore performed. For whereas, according to the method
in which engines are at present worked expansively, the steam employed to
produce each down stroke of the piston is made no further use of, but allowed
to go to waste, while by my said improvements the steam which is employed
in producing the down stroke is also again used to produce or assist in pro-
ducing the up or return stroke; and to exemplify in its simplest form the manner
in which the said improvements are performed or carried into effect, I have
shown in the Drawings hereunto annexed, marked Figures 1 and 2, the application
thereof to a single pumping engine of the ordinary description in use in Cornwall,
Figure 1 being a section, and Figure 2 a front view and elevation of so
much of an engine of that class as includes those parts required to be newly
constructed for the purpose of my said improvements. A', A*, is the cylinder,
which I make of double the usual length, and instead of being as usual of one
uniform bore throughout, it is divided into two parts, the under half A' being
about four times the area of the upper half A. B², B³, are two pistons
attached to one rod; B¹ being made to fit the under half of the cylinder A',
and B to fit the upper half of the cylinder A². C is a valve, by which steam
is admitted from the boiler into the upper or smaller half of the cylinder A³
(above the piston Bº). D is a pipe by which the steam is afterwards trans-
mitted (as herein-after explained) from the top of A, through the valve E, to
the bottom of the under or larger half of the cylinder A'. F is a pipe which
forms a communication from the space between the two pistons to the exhaus-
tion pipe G and condenser H, and by means of which a constant vacuum is
maintained between them. I is the exhaustion nozzle and valve. The manner
of working the engine as so constructed is as follows:-Supposing the engine
to have completed its up stroke, and that both pistons are at the top of their
respective cylinders, with a nearly perfect vacuum between them, established
through the medium of the pipe F; the under half of the cylinder is then
opened to the condenser (during the pause which takes place in pumping
engines between the up and down strokes), by which means a nearly perfect
vacuum is also established below the lower or larger piston B¹; steam is then
admitted from the boiler through the valve C, on to the top of the small
piston B (cutting off at one third of the stroke), and by its pressure there
acting against the vacuum underneath each of the pistons it forces down both
to the bottom of their respective cylinders. The valve E is now opened, when

page_text: the partially expanded steam above the small piston B flows down the pipe D
to the bottom of the larger half of the cylinder A', where, expanding to its
full extent under the larger piston B', and aided by the vacuum established as
before between the two pistons, it causes both pistons to reascend to the tops
of their respective cylinders with a force about equal to that which was exerted
in the down stroke. But whereas the force thus exerted in the up stroke is
not wanted in the single pumping engine for the mere purpose of raising the
pistons, and would, if not conterpoised, act injuriously on the pump rods, I
turn the same to a useful account by placing on the top of the large piston
weights (of iron or any other heavy substance) equivalent to about one half
of the load lifted by the engine, which weights being raised by the up stroke
diminish in exact proportion thereto the quantity of fresh steam from the boiler
required for the next down stroke. The engine may be worked without these
weights, but not of course so advantageously. The general effect of this im-
proved mode of constructing and working the single-acting engine is to double,
or nearly so, the power thereof; that is to say, nearly the same duty can be
performed by a single-acting engine on my improved plan as by an ordinary
Boulton and Watt double-acting engine. K is a steam bottom to the cylinder
for the purpose of keeping up the temperature of the steam under the large
piston B. A detached view of the top of the lower or larger half (A') of the
cylinder is given in Figure 3.
a, a, a, a, are apertures through which the
large piston B' may be inspected, having caps L, L, to screw on, as shewn in
Figure 2. In applying my said improvements to rotative engines, where equal
duty is required of both the up and the down strokes, there is no occasion for
the addition of any weights to the top of the large piston, and I find in practice
that the steam transmitted from the top of the small piston B2 to the bottom of
the large piston B' continues of pressure enough in every case (under the
arrangements and circumstances before specified) to produce an up stroke of
equal force to the down stroke.
And having now described the nature of my said Invention, and the manner
in which the same is to be performed; I declare that what I claim exclusive
right to under the before-recited Letters Patent is, the mode, herein-before
described, of constructing steam engines, to be used expansively, with one
cylinder divided into two parts of different areas, and with two pistons attached
to one rod, whereof the one fits the upper and the other the lower part of the
said cylinder; and the method, also herein-before described, of employing the
steam used in effecting the down stroke to produce also, or assist in pro-
ducing, the up or return stroke; and that whether the said improvements
are applied to lifting or to rotative engines; and whether the area of the two

page_text: parts of the cylinder are exactly of the relative dimensions herein-before set
forth, or of any other equivalent dimensions; and whether also the cylinder
and pistons are fixed or worked in a verticle, horizontal, or any other position;
and whether, finally, the cylinder with the pistons to fit is made of a strictly
circular or of any other suitable form. And such my said Invention being to
the best of my knowledge and belief entirely new, and never before used within
that part of Her said Majesty's United Kingdom of Great Britain and Ireland
called England, Her Dominion of Wales, and the Town of Berwick-upon-
Tweed, I do hereby declare this to be my Specification of the same, and that
I do verily believe this my said Specification doth comply fully, and in all
respects without reserve or disguise, with the proviso in the said herein-before
in part recited Letters Patent contained; wherefore I hereby claim to maintain
exclusive right and privilege to my said Invention.
In witness whereof, I, the said James Sims, have hereunto set my hand
and seal, this Twenty-fifth day of October, One thousand eight hundred