IMPROVEMENTS IN ROTARY ENGINES
Year: 1878

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for the
Invention of "IMPROVEMENTS IN ROTARY ENGINES." A communication from
abroad by Prince Alexis Sergucevitch Dolgorouky, of St. Petersburg, Russia.
Sealed the 29th November 1878, and dated the 12th October 1878.
:
COMPLETE SPECIFICATION filed by the said Sydney Pitt at the Office of the
Commissioners of Patents on the 12th October 1878.
SYDNEY PITT, of Sutton, in the County of Surrey. "IMPROVEMENTS IN ROTARY
ENGINES." A communication from abroad by Prince Alexis Serguecvitch
Dolgorouky, of St. Petersburg, Russia.
The proposed Invention has for its object an engine of new construction provided
with rotating pistons fit to serve as a motor acting by pressure of steam, water, gas,
or air, as suction and forcing pump for pumping water and other liquids, gas, or
air, and, lastly, as an apparatus for measuring liquids or gas.
In the annexed Drawings is represented in detail the construction of a double
engine of the proposed system acting as a steam motor.
Figure 1 is a side view of the engine.
Figure 2, a vertical longitudinal section.
Figure 3, a horizontal section along line 1-2 (Figure 2).
Figures 4 and 5, vertical sections by the lines 3-4 and 5—6—7—8 (Figure 2)
respectively.
Figure 6 a horizontal section of a part of the engine by the line 9-10-11-
12-13 (Figure 4).
The engine consists of a central cast-iron body or box A of double cylindric form
(Figures 4 and 5) strongly fastened on the immoveable foundation frame B. The
box A is provided with the flanges a, whereon the lids C are well fastened by
means of the bolts c. Between these lids and the flanges of the box A are placed
[Price 6d.]

page_text: the casings D, kept firm in their places by the bolts c (Figure 4); in these casings
are arranged the distributing valves and reversing slides as shall be hereafter
described.
The interior of the body or box A is divided in two equal compartments by the
central partition a¹ cast in one piece with the tubular cores a² in such manner as
to form on either side of the partition a¹ annular chambers A¹ and A", wherein
are moving the four pistons E¹, E², E³, E. These pistons are hollow, and their
section shows the form of segments. They are disposed in the chambers A¹, A",
with perfect symetry, and provided with the naves e, by means of which they are
placed on the steel axles F and firmly fixed in their places by the keys d. The
naves e, at their joining the pistons, are provided with flanges e¹ carefully turned
concentrically with the axles F, and actuately fitting in the corresponding cavities
made in the insides of the casings D, D, as shown in Figure 2. On the outside
ends of the naves e are fixed the steel pinions G, G, of equal diameter, gearing
into each other and causing all four pistons and their axles F to turn simul-
taneously.
In order to secure the firm position of the pinions G on the naves e, the side
surface of the latter is turned slightly conic, and provided at its end with screws,
whereon are fitting the iron nuts pressing upon the pinions G. Besides, the
protruding parts of the wedges d (Figure 6) are placed in corresponding grooves
made in the pinions G, whereby every motion of these pinions, independently of
the pistons E and the axles F, is prevented, and consequently not the least sliding
of these parts is possible. The ends of the axles F being turned in the shape of
slightly conic pivots or trunnions are placed into the two hard steel sleeves f,f,
carefully turned and adjusted to each other, whereof the inside one is firmly driven
on the corresponding pivot or end of axle F, and the outside sleeve is fixed in the
cup or shell C¹, cast together with the corresponding lid C, C, of the engine.
Similar steel sleeves support also the middle parts of the axles F (Figures 2
and 6).
The outside openings of the shells C¹ are screwed tight by the lids or stoppers C².
Three ends of the two axles F, F, are supported by such steel bushions, and the
fourth end only (the right-hand end of the lower axle in Figure 2) is coming out-
side through an ordinary stuffing box H, and supported by the axle box I fixed on
<the foundation frame B. This latter axle is at the same time acting as driving
shaft of the engine and connected with the transmission shaft F1 of some working
nechanism by means of the coupling sleeve K, or in some other manner.
The steam enters the engine by the pipe L through a tap and valve of ordinary
construction (Figure 1), and leaves the engine by the pipe M. Thus, the fresh
steam always enters the engine by the pipe N cast in one piece with middle part or
body A, and the exhaust steam leaves the engine by a similar pipe O cast in one
piece with the same middle part. By the pipe N the fresh steain enters the canal n,
going along the outside surface of the upper cylindrical part of the box or body A,
and communicating with the longitudinal (side) canal n, wherein the steam is thus
admitted, in order to be directed to both sides (as shown in Figure 3), and to fill
the whole inside space of both lids C. For this purpose the casings D, D, are
provided with ports or openings (passages) n³ remaining constantly open:
Besides the passages n³, there are in the vertical partition of each of the
casings D the passages.n³, n³, n³, nt, no, n³, no, no, by means of which steam is
'admitted into the middle part or box A, and the exhaust steam led out of this box
in the following manner: On the naves e of the pistons E are loosely set the
distributing valves P (one on each nave) having the shape of flat sectors and
covering a little more than half the circumference. The outside part, of each
valve P has the form of a hollowed seginent or box covering the passages n' and n³.
On the inside ends of the sectors P are screwed the pins p fitting in corresponding
grooves or cavities of the reversing slides Q. The latter are connected by means of
the rods q with the short arms of the reversing lever R, pivotted to the axle S,

page_text: supported by the handle T, screwed to the outside wall of the casings D. When
the reversing lever out of the vertical position, shown in Figure 4, is put in the
position corresponding to working "ahead with full pressure" (position I, Figure 4)
the slides Q, acting upon the pins p of the distributing valves P, will turn these
slides in such position as to open the passages n³, n³, (although, the passages n
being at the same time partly shut, it has no influence on the action of the engine).
The passages n³ are going through (Figure 6), and, with due position of the
valves P, connect the interior space of the lids C with the chambers A¹, A", of the
body or box A. In consequence hereof, when the valves P are turned so as to open
the passages n³, the fresh steam filling the lids C, as afore-mentioned, will pass into.
the chambers A¹, A", and act upon the pistons E, compelling them to rotate in the
direction shown in Figures 3 and 5 by arrows. With such position of the valves P,
the fresh steam will constantly act on the one or the other of the pistons E with
full pressure, and as long as the engine is working there will be not one moment
when all four passages n³ are shut at the same time (these passages are shut by
turns by the end walls of the pistons E lying close to the vertical plates of the
casings D). The exhaust steam issues on the opposite side of the piston E, by the
passages no, which, like the passages n³, are going through. By these passages the
steam passes from the chambers A', A", into the hollowed segments of the valves P
(Figure 6), bringing the passages n in connection with the passages n¹ (Figure 4).
The latter passages, unlike the foregoing, are not going through but are only made
in the front surface of the vertical plates of the casings D (Figure 2), bringing the
hollowed segments of the valves P in communication with the ring formed outside
chambers D of the casings D. Thus the exhaust steam enters into these chambers
and thence is led by the communicating canal 01 (Figures 3 and 5) into the pipe O,
and lastly into the exhaust pipe M (Figure 1).
To obtain a more economical working of the engine, the proposed construction is
provided with an apparatus for expansion of steam, i.e., for stopping or suspending
the supply of steain when wanted. For this purpose the vertical plate of each
casing D is provided with one more passage ne, also going through (Figures 4 and 6),
which is shut at the time of full steam pressure by the flat part of the valves P, and
opened when the reversing lever R is in vertical position (II. in Figure 4), because
at such position of the lever the passages no fall together, with the openings made
in the said flat part of the valves P, being of like form with them (Figure 4).
The passages n are arranged exactly in the cavities wherein the flanges e¹ of the
piston naves e (Figures 2 and 6) are placed. These flanges are provided with the
openings e (shown in Figure 4 by pointed lines) by whose falling together with the
passages the communication between the interior space of the lids C and the
chambers A', A", is re-established, i.e., the entering of steam into these chambers
is taking place. But as soon as by the further motion of the pistons, the
passages no are covered by the whole part of the flanges e', the admission of steam
into the chambers A¹, A, is stopped and the steam is acting by expansion; the
length of time during which steam is admitted depends on the size of the
passages n and of the corresponding openings of the valves P, giving thus the
possibility to change the degree of expansion within certain limits.
In the case represented in the Drawings the steam is acting with full pressure at
about, of the working stroke of the pistons.
Moreover, the above-described construction of engine permits to change the
direction of the piston's rotation, i.e., to make the engine work backwards, indeed
bringing the lever R out of the vertical position, corresponding to expansion, into
the position marked III. in Figure 4; the slides Q will turn the distributing
valves P in such position as to shut the passages nº. The passages n³ communicate
by means of the hollowed part of the valves P with the passages n*, serving to let
the steam out, and the passages n³ are opened to admit steam, which will act upon
the pistons in a direction opposite to the former, and thus cause the engine to work
backwards.

page_text: .
This reversing of the engine, as well as the distribution of steam, in case of
normal working of the engine, can also be obtained by a four-ways distributing tap
of proper construction placed on top of the cylinder A, and letting the steam pass to
the engine in the direction wanted. This contrivance would simplify the con-
struction of the engine, and in some cases offer considerable advantages, the
distributing passages becoming superfluous except of course the expansion
passage ne
It is to be observed that in consequence of employing four pistons disposed
symmetrically in the chambers A', A", of the engine, the axles F, F, are completely
balanced in the transversal direction and, besides, the upper axle F being placed
altogether inside the engine is likewise balanced in the longitudinal direction,
because the fresh steam arrives from either end of it.
As to the lower axle F (the driving shaft), one end of which is coming outside, for
its balancing in the longitudinal direction, the piston E³ is provided with a thorough
canale (Figure 2) by which the fresh steam enters into the interior space of this
hollow piston, and, pressing it against the vertical plate of the left-hand casing D,
balances the steam pressure, acting upon the lower axle F in the opposite
direction.
For. ascertaining the number of revolutions of the engine, the upper axle F is
provided at its end with a small rod y, passing through the stuffing box Z, and
connected with a counting mechanism of ordinary construction.
The principal advantages afforded by the engine of the proposed construction are
the following:-
1. The economical use of steam, depending on the expansion obtained in the
proposed engine.
2. The solid construction of the engine and the diminished wear of its parts in
consequence of the employment of sleeves or brushings of hardened steel.
3. The regular even working and very considerable number of revolutions of the
engine obtained in consequence of its perfect equilibrium, securing at the same
time an increase of working power.
4. The facility of rapidly changing the direction of the engine's motion.
First. In a rotary steam engine the combination of two symmetrically disposed
pistons fastened on each axle, substantially as and for the purpose set forth.
Second. In a rotary steam engine, the means of supplying steam into the interior
space of the lids C from both ends of the engine, substantially as and for the
purpose set forth.
Third. The passages n³, n³, n³, in combination with the distributing valves P,
substantially as described and shown.
Fourth. The passages no.in combination with the openings e³ of the piston
flanges e¹ and the valves P, whereby expansion of steam is obtained, substantially
as described and shown.
Fifth. In a rotary steam engine, the reversing slides Q in combination with the
valves P and the reversing lever R, by the action of which parts are obtained at
pleasure,―
a. Head motion of the engine with full pressure.
b. Head motion of the engine with expansion of steam, and
c. Backward motion of the engine, substantially as described and shown.
Sixth. In a rotary steam engine, the bushings or sleeves of hardened steel,
substantially as and for the purpose set forth.
Seventh. The canal es leading from the interior space of the lids C into one of
the hollow pistons and causing the complete equilibrium of all pistons, substantially
as described.

page_text: Eighth. The engine with rotating pistons proper to serve as a motor, pump, and
measuring apparatus for liquids, constructed and working substantially as described
and shown.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand and
seal, this Twelfth day of October, in the year of our Lord One thousand
eight hundred and seventy-eight.
SYDNEY PITT. (LS.)