IMPROVEMENTS IN STEAM ENGINES
Year: 1865

page_text: LETTERS PATENT to James Stevenson, of No. 19, Salisbury Street,
Strand, London, for the Invention of "IMPROVEMENTS IN STEAM ENGINES."
--A communication from abroad by Giovanni Batista Venzano, of
in the Kingdom of Italy. Engineer.
COMPLETE SPECIFICATION filed by the said James Stevenson at the
Office of the Commissioners of Patents, with his Petition and Declaration
on the 18th August 1865, pursuant to the 9th Section of the Patent
Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
STEVENSON. of No. 19. Salisbury Street, Strand, London, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
STEAM ENGINES," and have petitioned Her Majesty to grant unto me and my
executors. administrators, and assigns, Her Royal Letters Patent for the
same, and have made solemn Declaration that the same is a communication
to me from abroad by Giovanni Batista Venzano, of Genoa, in the Kingdom
of Italy, Engineèr.

page_text: NOW KNOW YE, that I, the said James Stevenson, do hereby declare
that the following Complete Specification, under my hand and seal, fully
describes and ascertains the nature of the said Invention, and in what
manner the same is to be performed, in and by the following statement
and accompanying Drawings.
My Invention consists in substituting for the ordinary forms of either
reciprocating or rotary steam engines heretofore in use a rotary engine or
apparatus of novel description, whereby (as in the case of a reciprocating
engine) instead of first obtaining the usual rectilinear motion which must
subsequently be converted into a rotary motion either by a crank or other
equivalent mechanical contrivance the rotary motion is at once obtained by
the direct impact and continued pressure of steam upon the periphery of a
cylinder or wheel.
1 prefer to employ a double wheel or a pair of wheels side by side (or there
may be several such wheels connected together side by side) and arranged to
work right and left. or ahead and astern, furnished with a series of divisions
forming buckets or cells into which the steam is admitted, and causes the
wheel or wheels to revolve in a direction dependent upon the position of the
said divisions which are set in contrary directions in the two wheels or sets of
wheels so as to allow of the engine being worked in either direction, that is
to say, the one being intended to drive the machinery forward, and the other
to drive the machinery backward, the direction of motion being reversed by
changing the supply of steam from one wheel or set of wheels to the other.
On one side of each of the wheels or sets of wheels, and extending around a
portion of the periphery thereof, is fitted or mounted a steam chest or case,
into which steam is admitted from the boiler, to act upon the wheel or wheels
forming the prime mover. This steam chest or case is fitted steam-tight
against the periphery of the wheel or wheels when in action being pressed
into its place by a suitable screw or screws or equivalent contrivance, the
portion of the wheel or wheels, and the buckets or cells contained therein, to
which the steam chest or casing is fitted, being grooved, and by the aid of
metallic or other suitable packing the wheel or wheels and the buckets or
cells therein contained are made to work steam-tight through the steam chest
or casing which extends in its length over several buckets or cells, now the
steam having acted upon the divisions of the cells or buckets which are within
the steam chest or casing passes by means of a suitable conduit or pipe to the
condenser. Instead, however, of allowing the steam thus to escape from the
cells or buckets as they pass from the steam-tight chest or casing into the

page_text: open jacket or casing in connection with the condenser. I prefer in some cases
to adapt the following method:-The steam having effectually acted upon the
radial divisions of the cells or buckets is made to pass from each through a
pipe or channel leading from each bucket and converging to the central axis
upon which the wheel or wheels are mounted, and which axis in this arrange-
ment is made hollow and connected with the air pump and condenser; this
hollow axis has ducts corresponding with the cells, and this again is fitted
with a hollow plug forming a valve by which the passages corresponding with
the buckets which are covered by the steam chest or casing are kept closed, and
the connection with the condenser is thereby cut off, whilst communication with
the condenser is permitted between such of the buckets as have emerged from
the steam chest or casing in their course of rotation, and the steam which has
expended its force is thus condensed by means of a surface condenser placed
in any convenient position, or by means of an ordinary jet condenser, as may
be preferred. Instead of employing a condenser of any kind or description
the steam may be allowed to escape through the exterior casing or boxing
surrounding the rotary engine, and from thence direct into the chimney; or
the steam after it has done its work may be made to pass through the hollow
axis of the rotary engine, and from thence through a blast pipe into the
chimney to promote the combustion of the fuel in the furnace.
In the arrangements described the main shaft has mounted upon it a toothed
wheel or a pinion (as the case may be) which gearing into another toothed
wheel (or pinion) transmits the power generated in the rotary steam engine
to the propeller or other machinery to be driven.
The annexed Sheets of Drawings shew views of a marine engine constructed
in accordance with this Invention, Figure 1, Sheet 1, shews the front
elevation of the engine as placed in a ship, a portion being in section; Figuro
2, Sheet 2, is a side view of the same, partly in section, and shewing
a section of the boiler; Figure 3, Sheet 2, is a plan of the same, partly in
section; Figure 4, Sheet 2, is a detached view, shewing in side elevation a
modification in the arrangement of gearing, shewn at Figures 1 to 3 inclusive;
in these several Figures like parts are denoted by corresponding letters. A,
boiler; B, B, steam pipes governed by valves c, c'; D, steam wheel for
forward motion; D', steam wheel for backward motion; d, d', the series of
cellular compartments or buckets; E, outer casing containing the wheels
D, D; F, F, covers or steam chests fitting steam-tight against the periphery
of the wheels; G, G', screws for adjusting the pressure of the steam chest
against the periphery of the wheels; H, H', brackets for screws G, G';

page_text: I, condenser as referred to in the arrangement herein-before described; J, J,
main shaft; K, K, K', bearings for main shaft; L, L', pumps actuated from
main shaft; M, toothed wheel in Figures 1 to 3, and the toothed pinion in
Figure 4; N, pinion actuated by M, in Figures 1 to 3, and the toothed wheel
in Figure 4; O casing round M and N; P, P. P', horizontal stays to secure
the bearings K, K, K¹; Q, propeller shaft; R, bearing for propeller shaft;
S, S', guides to steady D, D: T, waste steam pipe; U, U', exhaust channels,
and V, VI, exhaust pipes leading to the condenser in the second described
arrangement.
In the first described arrangement the action of the engine is as follows:-
The steam passing from the boiler A through the steam pipe B and steam
chest F, and being discharged into the cells d, d', acts upon the radial
divisions of the steam wheel D and causes it to revolve, the steam being
prevented from escaping until the proper time by the cover F; then having
passed through the cells it is condensed in the condenser I. In the second
described arrangement the steam instead of passing into the casing F will
flow into the channels U, U¹, shown in dotted lines, and thence through the
pipes V, V, shown also in dotted lines, into the condenser, which instead of
being placed in the position shown in Figure 2, Sheet 2, of the accompanying
Drawings may be disposed so as to be best adapted to this arrangement, and
be either an ordinary injection condenser, or a surface condenser of any
convenient construction may be employed.
In the accompanying Drawings, Figures 1 to 3, a toothed wheel is shewn
on the main shaft or axis of the engine gearing into a pinion on the propeller
shaft, but for the purpose of enabling a higher velocity to be obtained by the
rotary engine the main shaft or axis of the engine may have the pinion fixed
upon it, and the toothed wheel may be on the propeller shaft,, as shewn in
Figure 4, Sheet 2.
Lubricators are provided to prevent excessive wear and tear due to
friction between the outer edges of the rotary engine and the steam-tight
chest and covers F.
Having now described my Invention of "Improvements in Steam Engines,"
and having illustrated the same in the accompanying two Sheets of Drawings,
I wish it to be understood that what I claim as my Invention is not the
production of a rotary motion by the action of steam impinging upon the
periphery of a wheel or drum, as that is old and well-known; but what I
claim as my Invention is,-
The construction of rotatory steam engines with drums,, wheels, or inward flow

page_text: turbines aforesaid. having close fitting steam chests adjusted to the peripheries
of such drums or wheels or inward flow turbines, as herein described, and as
illustrated by the accompanying Sheets of Drawings.
In witness whereof, 1. the said James Stevenson, have hereunto set my
hand and seal, this Ninth day of August, One thousand eight hundred
and sixty-five.
JAMES STEVENSON. (L..s.)