IMPROVEMENTS IN STEAM ENGINES
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by William Clark at the Office of
the Commissioners of Patents, with his Petition, on the 11th July
1860. A communication from abroad by Mr. Charles Claude Etienne
Minié, formerly Major in the Army, of Paris, in the Empire of
France.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer & Patent Agent, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STEAM ENGINES," to be as follows:-
This Invention relates to a new arrangement of steam engine for economizing
steam in the production of motive-power. It consists in making the cylinder
& its accessories rotate on an axis forming the driving shaft. The piston bas
on each side two rods, traversing fixed guides suitably curved for producing
the rotating movement of the cylinder, and also of the motive shaft which is in
one with it.
The power of a steam engine with connecting rod and crank may be
estimated by multiplying the pressure acting on the piston by the number of
turns of the crank, and by the mean radius of said crank, thus r being its
true radius, it is known that the mean radius varies between 0 &r, For
example, in a horizontal engine, zero is when the connecting rod and crank
form a prolongation one from the other, viz., 1st, when the crank in turning
has described an angle of 90°, & 2ndly, when continuing its rotation it arrives
at 360 degrees, in other words, "the dead points;" on the contrary it is at r
when the rod and crank have passed into the two other exact divisions of a
circle, that is to say, to zero and to 180°. It is either below or above zero
in all intermediate positions, in fact, increasing from 0 to r, so that the exact

page_text: inean estimate of the constant angle at which the crank works is 45°; hence
the leverage of the crank for producing the motion is obtained by projecting
its length on an axis inclined at 45°.
In this improved arrangement of steam engine, the curved guides before
mentioned are so applied that the arms of the lever motor describe a maximum
angle of 46°, 40 seconds, thus producing the first item of economy in the
stcam. I further economize it as follows:-The piston rods taking into curved
guides perform the work of cranks in this engine, and as the momentum of
each acts in the same direction, that is, tending to effect together the rotation
of the motive shaft, it follows, that by this said momentum taken collectively
I have constant leverage equal in length to the height of the cylinder, in
addition to the length of the piston rods.
In the annexed Drawing I have illustrated this improved arrangement of
steam engine, with rotating cylinder and curved guides. Fig. 1 is a plan, and
Fig. 2 is a side view of this engine. In the two Figures the same letters of
reference indicate like parts seen in different positions.
a, guides forming the framing of the engine, consisting of six arcs of circles
of the same radius intersecting one another, constituting curves, having six
points of inflexion. These guides are in duplicate, for engines working in
various directions, but may be single for those working always in the same
direction. b, cylinder, having an axis cast on it, which serves as the motive
shaft; c, steam valve working in the interior of the pivot, and receiving its
motion automatically; d, ordinary piston, working in cylinder b, furnished with
two rods e&f, passing through two stuffing boxes on each end of the cylinder.
These two rods are furnished with truck rollers or other suitable parts
which engage with and traverse curved guides a.
valve c into the cylinder 6 the piston moves, and
to traverse the curved guides, and while one rod
distance, the other rod enters it a similar distance. 9, guides for maintaining
the rigidity of the piston rods. The dotted lines show a second position of the
rotating cylinder of this improved engine. It will thus be understood that the
piston rods, which perform the part of lever motors, work constantly at the
same angle of 46 degrees, 40 seconds, and that their lengths of leverage
added together will be the length of the cylinder plus the length of the
piston rods.
By admitting steam by the
causes the ends of the rods
leaves the cylinder a certain