Improvements in Steam Engines
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the
Office of the Commissioners of Patents, with his Petition, on the
20th July 1875 -A communication from abroad by Cyrın Leandre
Van der Elst, of Paris, in the Republic of France, Engineer.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "Improvements in Steam Engines,” a communication to me
from abroad by Cyrın Leandre Van der Elst, of Paris, in the Republic
of France, Engineer, to be as follows .—
This Invention relates to a peculiar arrangement of continuous direct
action steam engine in which the ordinary cylinders are dispensed with,
and the steam is caused to act directly and without interruption upon the
driving shaft, and it consists in the employment of a steam driving wheel
in substitution for the ordinary cylinders and serving as a fly wheel,
which wheel is composed of arms or vanes forming volute or spiral or other-
wise curved channels or passages divided by transverse partitions, and is
keyed upon the driving shaft so as when acted upon by the steam to
impart motion thereto. The interior may however be modified in
various ways, for example, it may be formed of a series of passages or

page_text: The shaft is made hollow and the inner or outlet ends of the volute or
curved channels open into it, and the steam having produced its effect
upon each of them escapes into a condenser situate by preference in a
linc therewith or to a chimney or elsewhere as desired The shaft
which is firmly supported in suitable bearings in the frame, carries a
pulley or other contrivance for transmitting the power, and also a fly
wheel if required.
In the first chambers of the vanes the steam may be employed at full
pressure, but it can be expanded in the succeeding chambers, with this
object the sections of the ports or orifices are sucessively diminished
from the orifice of the first chamber, to, say, the 8th chamber, beyond
wluch the orifices or communications of the following chambers the
capacity of which is augmented or enlarged.
The steam generated in the boiler and being directed towards the
condenser or the outlet apertures communicating with the open air, acts
then continuously in the spiral passages or volutes as the orifices and
ports remain constantly open. The ongino driver can limit the opening
of the inlet valve or poit at will, and thus produce an expansion even
in the first chambers, in order to effect which it is simply necessary to
raise the closing cam lever to a sufficient extent to cause the rollers to
assume such a position that the sliding valve covers the aperture
sufficiently to produce the expansion desired.
A graduated sector outside the box containing the cam levers may be
employed for the purpose of indicating the position the can.s should be
caused to assume in the different cases of expansion. This wheel
moreover forms an accumulator, the weight of which may be regulated
according to circumstances, citler by filling up the vacant spaces
between the vanes forming the spiral channels or volutes, or by
increasing the thickness of the sides of the latter towards the circum-
ference of the wheel.
It is obvious that the wheel may be mounted upon a vertical or
inclined axis if desired, and that the Invention is applicable as a
stationary, portable, compound, locomotive, or marinc engine, and to
other purposes for which a steam engine may be employed.
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