IMPROVEMENTS. IN ROTARY STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to Willem Hubertus Jacobs, of Haarlem, in the Kingdom of
the Netherlands, and Andreas Jacobus Jacobs, of Haarlem aforesaid, both
Manufacturers of Steam Engines, for the Invention of "" IMPROVEMENTS. IN
ROTARY STEAM ENGINES."
Sealed the 23rd November 1877, and dated the 25th May 1877.
PROVISIONAL SPECIFICATION left by the said Willem Hubertus Jacobs
and Andreas Jacobus Jacobs at the Office of the Commissioners of Patents on
the 25th May 1877.
WILLEM HUBERTUS JACOBS, of Haarlem, in the Kingdom of the Netherlands
and ANDREAS JACOBUS JACOBS, of Haarlem aforesaid, botli Manufacturers of Steam
Engines. "IMPROVEMENTS IN ROTARY STEAM ENGINES."
This Invention consists principally of two cylinders, one working inside the other,
the larger or outer cylinder being fixed to a base plate. The inner cylinder, which
is much smaller than the outer one, is fixed to the main shaft in such a position as
to be kept in contact with the outer cylinder along one side, forming a lunate space
on the opposite side. The piston, fitting in a groove in the small cylinder, presses
with a self-adjusting head against the inside of the outer cylinder, sufficient pressure
being obtained by allowing steam to be admitted through the main shaft to the
under side of the piston. Between the ends of the two cylinders is a disc to keep
the ends of the inner cylinder and piston steam-tight.
The steam and exhaust ports are placed in the outer cylinder, one on either side
of the part in contact with the inner cylinder, so that any amount of useful expan-
sion can be obtained, and the exhaust port being always open the back pressure is
very small.
On the admission of steam through the steam port the inner cylinder and piston
is driven round until the piston passes the exhaust port, when the steam is allowed
to escape and a fresh supply admitted so as to make the action continuous..
.-

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Willem Hubertus Jacobs and Andreas Jacobus Jacobs in the Great
Seal Patent Office on the 24th November 1877.
WILLEM HUBERTUS JACOBS, of Haarlem, in the Kingdom of the Netherlands,
and ANDREAS JACOBUS JACOBS, of Haarlem aforesaid, both Manufacturers of Steam
Engines. IMPROVEMENTS IN ROTARY STEAM ENGINES."
And in order that our said Invention may be properly understood, and, if
necessary, carried into practical effect, we shall now proceed to describe the same
more particularly, reference being had to the accompanying Drawings and to the
letters and figures marked thereon, that is to say,-
-
Figure 1 is a transverse vertical section of our improved rotary engine taken on
the line a, b, Figure 3.
Figure 2 is a corresponding section taken on the line c, d.
Figure 3 is a longitudinal section, showing also the lateral extension of the main
shaft carrying at its free extremity the fly wheel.
The framing of the engine consists of a hollow rectangular or other suitably
shaped base or bed plate A, on which the engine is fitted. The main cylinder B is
firmly secured by bolts to the framing A. One of the covers of the cylinder is
made with a suitable stuffing box C, through which the main shaft D passes; this
box is fitted with brasses in the usual manner, and forms the bearing for that
portion of the shaft, as is well understood in engines of this class. The inner end
of the stuffing box is prolonged within the cylinder cover for a purpose that will be
herein-after explained. The cover at the other end of the cylinder B is also
provided with a laterally projecting cylindrical recess or bearing E to receive the
left-hand extremity of the shaft D, as shown more particularly in Figure 3. This
journal box may be arranged with a steam cock F, as shewn, or it may be made
open-ended to suit cases where it is desirable to carry the driving shaft beyond that
end of the cylinder: The cock is very conveniently placed for engines made
according to this Drawing, but in cases where it is necessary to carry the main
shaft through both ends of the cylinder the cock may be placed above the bearing E
so as to avoid interfering with the shaft.
The internal arrangement of the engine is as follows: The main shaft D has
attached to it a smaller cylinder G, which works inside the main stationary
cylinder B, and it rotates with the shaft when put in motion by the induction of
steam. This cylinder G is grooved longitudinally, and is recessed internally, as
more particularly shewn in Figures 1 and 2. These recesses or reservoirs are of
great importance to this Invention, and will be more fully described further on.
They receive the piston H, which forms a self-adjusting diaphragm that divides the
cylinder B into two steam chambers, one forming the inlet I and the other the
exhaust J as the piston in its rotation passes the ports. These chambers are kept
steam-tight by the contact of the cylinder G with an adjustable metallic packing K,
which consists, by preference, of a bar of cast iron carried in a suitable groove
extending along the lower part of the main cylinder B. The packing K is kept
tightly in contact with the cylinder G by means of a secondary metal bar L, which
is fitted beneath the packing K. The bar L is slightly tapered longitudinally, and
by means of the screw and hand wheel M the requisite pressure may at all times
be readily maintained. We do not, however, confine ourselves to this secondary
metal bar Lalone for keeping the metallic packing K tight, as the bar L can be
removed and two or more springs introduced in its place.
The piston H, which forms the other portion of the internal part, consists of a
metal partition, having fitted to it a self-adjusting head of a segmental shape, as
shown at N in Figure 4. The part N corresponds in curvature to the face of the
cylinder, and is bolted to the piston in such manner that it adjusts itself accurately
to the cylinder, and thus ensures a steam-tight junction of the contiguous parts.
In the example of the engine given there are two steam ports O, as shown in

page_text: Figure 1, and the corresponding exhaust ports P are delineated in Figure 2. - The
steam is introduced through the cock F, whether placed at the end or above, as the
case may be. If above, a hole is bored through the cover of the main cylinder, into
which the cock is fixed; there is a small space between the inside of the cylinder
cover and the flange which connects the main shaft to the inner cylinder; through
this space the steam passes to the lower part of the piston groove.
With regard to the exhaust (if so it can be called) it is effected as follows:-
When the piston has been raised to its highest point by the steam it gradually
begins to descend, and if no means were provided for the escape of steam the
pressure inside the groove would become momentarily excessive; to avoid this, self-
acting valves (these valves are not shewn in the Drawing) are fitted into the inner
cylinder in connexion with the groove; when the pressure becomes too high the
valves open-and let some of the steam escape. But these escape valves cause the
engine to be very much complicated and also some loss of steam. To avoid this
difficulty we have altered the dimensions.
The alterations are as follows:-The escape valves to be done away entirely,
the two cylinders to be made double the diameter, and only one-half the length of
that in the present engine, the piston and groove to be reduced to one-half their
present thickness; by this means the piston will be reduced to one-fourth its present
dimensions. By augmenting the diameter of the inner cylinder we obtain space
enough to enlarge the recesses or reservoirs to ten or twelve times their present size,
the recesses or reservoirs of the present engine being found too small, which caused the
necessity of escape valves. By this reduction of the piston and enlargement of the
reservoirs to the above extent, the extra pressure caused by the piston descending
in its groove will be reduced to a mere nothing, in fact it may be compared to a
needle introduced into a pint bottle full of steam. It will be evident that with
these alterations the improved piston will be reduced in area to one-half of the old
one; to compensate for this the new piston will move at double the speed of the old
one, so that the power of the two engines will be the same, and thus the engine
will be much simplified, work smoother, and not be liable to get out of order. The
admission of steam and the reserving of the engine is effected by a hand lever Q, or
by any other suitable mechanical equivalent therefor.
Between the cover of the main cylinder B and the inner cylinder G a metal
disc R is interposed, and by prolonging the stuffing box Cinwards until it touches the
disc an effective steam-tight joint is obtained, free from friction or nearly so. We do
not confine ourselves to this kind of packing alone, as the same can be effected by
introducing steam between the disc and the cover of the main cylinder, or by placing
three or more spiral or other springs between the disc and cylinder cover; the disc is
provided with a metallic or other packing to keep it steam-tight within the main
cylinder; this packing is similar to those used for pistons of common steam engines.
The arrangement of the steam and exhaust ports on each side of the cylinder G
admits of the easy regulation of the "cut-off" and the consequent useful expansion
of the steam, and in adapting this kind of engine to steam boats, locomotives,
tramway cars, and other vehicles, the reversing lever or its equivalent may be
arranged in any convenient manner so as to obtain an instant reversal of the
motion.
With slight alterations in some of the details these engines may be driven by gas,
compressed air, or water pressure.
In arranging these engines to take the place of the ordinary double cylinder
kind and to reduce the dead point to a minimum, at the same time provide for the
instant stopping, starting, and reversing, we prefer the arrangement shewn in the
diagram, Figure 5, which will answer all the purposes and requirements of double
engines. Here the single cylinder is arranged with double pistons, as indicated in
the diagram, the foregoing description of which, as applied to the single piston,
renders further explanation unnecessary.
Having now described. and particularly ascertained the nature of our said
Invention of improvements in rotatory engines, and in what manner the same may

page_text: be carried into effect, we wish it to be understood that we do confine ourselves
to the precise details of mechanical arrangement we have herein-before described
and shewn, as the same may be varied without departing from the essential and
novel features of our Invention; but what we do claim and desire to secure under
the herein-before in part recited Letters Patent is,__
First. The general arrangement, construction, and combination of parts together
forming our improved rotary engines, substantially as herein-before described and
shewn in the accompanying Drawings.
Second. The mechanical arrangement of the inner cylinder with its self-adjusting
piston, which is kept in its proper position by the steam in lieu of springs, substan-
tially as herein-before described and shewn in the accompanying Drawings, or any
merė modification of the same.
Third. The use and application of the metallic adjustable packing or the
equivalent therefor, substantially as herein-before described and shewn in the
accompanying Drawings.
In witness whereof, I, the said Willem Hubertus Jacobs, for myself and the
said Andreas Jacobus Jacobs, have hereunto set my hand and seal, this
Twentieth day of November, A.D. 1877..