IMPROVEMENTS IN ROTARY ENGINES
Year: 1885

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I!ALFRED JULIUS BOULT of 323 High Holborn in the county of Middlesex,
Engineer do hereby declare the nature of this invention for "IMPROVEMENTS IN
ROTARY ENGINES (a communication from Henry Sewrey of Barrie, Ontario,
Canada, Engineer) and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The object of the Invention is to construct a rotary engine in which the
revolving piston head is propelled by steam admitted so as to balance the revolving
piston head, and regulated by valves arranged to cut off the steam at any desired
point of the revolution; and it consists essentially of a winged piston head placed
within a properly constructed cylinder having two cut-off valves placed opposite to
each other and so operated that they simultaneously admit the steam on opposite
sides of the piston head; revolving cylindrical blocks being placed within the
cylinder against the piston head to divide the cylinder so that the steam admitted
through the two valves opposite to each other shall act simultaneously on the two
wings of the revolving piston head, and separating the two bodies of steam so
admitted; the whole being arranged and constructed substantially in the manner
hereinafter more particularly explained.
Figure 1 is a perspective outside view of this improved rotary engine.
Figure 2 is a view of this improved rotary engine with the front cover off the
cylinder.
Figure 3 is a cross section through a b.
Figure 4 is a front section through x, y.
Figure 5 is a sectional detail, showing the bearing box of the cylindrical dividing
block.
Figure 6 is an enlarged perspective detail of the cut off valve.
In the drawings, like letters of reference indicate corresponding parts in each
figure.
A, is the cylinder, B the front cover, C the back cover, D the piston, and E the
wings held within recesses in the piston, D fitted against the inner. circumference
of the cylinder, and against the inner face of the front cover, B, and the inner face
D
073

page_text: of the adjustable plate F, which is next to the back cover C, and is adjusted by
the set screws G, so that any wear can readily be taken up in order to maintain
steam tight joints on both faces of the piston D, and its wings E.
H are cylindrical blocks located opposite to each other within chambers formed
in the cylinder A. These are termed dividing blocks as they form a division in
the cylinder. A semi-circular recess is formed in each block, H so as to allow the
wings E to pass the blocks when the piston is revolving. It will be understood
that the blocks H revolve so as to create as little friction as possible in their
contact with the piston D, and also in order to permit the wings E to pass the
blocks H, during the revolving of the piston D. In order to ensure regularity in
the revolving of the blocks H, gearing shown in dotted lines in Figure 1 is provided
by which motion from the shaft I, of the piston is conveyed to the spindles J of
the blocks H; the said blocks being driven by this gearing so that the recess & in
each block shall come opposite to the interior of the cylinder A at the moment
when the wings E arrive at the blocks H which blocks resume their connection
with the piston D, the moment after the wings have passed.
K, are rolling cut off valves held in suitable steam chests located on opposite
sides of the cylinder A, and communicating with its interior by the steam ports e,
which steam ports enter the cylinder next to the blocks, H, on the under side of
one and the upper side of the other; the steam entering the chests of the valves K
through the steam pipes, L, and passing through the port f, made in the centre of
each of the said valves. These valves are operated from an eccentric M placed on
the shaft I, as indicated in Figure 1 which through the connection exhibited in
Figure 1 imparts a rocking movement to the valves K, so that the port f, in each
valve passes and repasses the respective steam port e, thereby alternately
admitting and cutting off the supply of steam admitted into the cylinder A,
through the ports e, the valve gear being designed to effect the cut off at any
desired point in the revolution of the piston D, so that the said piston shall be
propelled by the expansion of the steam.
As any skilled mechanic would understand how to set the valve gear to effect
the desired purpose it is not necessary for me to describe the construction and
manipulation of the valve gear in question, as the foregoing description and
accompanying drawings will be sufficient.
All the principal parts of this improved rotary engine have now been referred
to but before summing up the points of this invention attention is first drawn to
one or two minor features of construction. It will be noticed that the cylindrical
blocks H do not fit tightly entirely round the surface of the chambers in which
they are held, but that a small space y extends from the steam port, e partially
around the block. This space g, admits sufficient steam behind the blocks H, to
press the opposite side of each against the circumference of the piston D in order
to ensure a practically steam tight connection between the blocks and the piston.
It should also be mentioned here that the spindles J, of these blocks H, are carried
in adjustable bearing-boxes N (see Figure 5) which bearing boxes are each adjusted
by means of the set screw O.
On the back side of each wing E a block his usually placed so as to reduce the
size of the steam space during the period that the wing is passing the recess d. It
will also be noticed that the cylindrical blocks H are hollowed out which is
generally done for the purpose of lightening the side opposite to the recess in order
to balance the block.
On reference to figure 4 the operation of this rotary engine will be understood.
The piston is supposed to be travelling in the direction indicated by arrow and
the wings E have just passed the block H which are thus revolving in the
direction indicated by their arrows. The ports e, and ƒ are now opposite to each
other, and consequently the steam is being admitted into the cylinder A behind the
back of each wing, E, the blocks H forming cut offs or dividers to prevent the
steam admitted at the back of one wing finding its way in front of the other wing;
the space in front of each wing E, being emptied of steam through the exhaust

page_text: ports P, which are constantly open, and communicate with the interior of the
cylinder on the side of each block, H, opposite to that at which the steam ports e,
enter; consequently at the wings reach the blocks H, they pass by the exhaust
ports P, and the old steam is allowed to escape before the new steam is admitted.
It will be understood that by admitting and cutting off the steam on two
opposite sides simultaneously the revolving piston is completely balanced at all
points of its revolution thus reducing to a minimum the liability of the parts to
wear.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I declare that what I claim is
1. The revolving piston D, provided with two wings E opposite to each other,
in combination with the cylindrical dividing blocks H, journalled in chambers,
formed in the cylinder A opposite to each other, and recessed at d, substantially as
and for the purpose specified.
2. The revolving piston D, having wings E opposite to each other, and
suitably journalled within a cylinder A in combination with the revolving
cylindrical dividing blocks, H and rolling cut off valves K arranged substantially
as and for the purpose specified.
:
3. The revolving piston D, provided with wings E opposite to each other, and
suitably journalled within a cylinder A, provided with steam ports c, entering the
cylinder on one side of a dividing block, and an exhaust port, P, entering the
cylinder on the opposite side of the dividing block, substantially as and for the
purpose specified.
4. A revolving piston D, provided with wings E opposite to each other, and
suitably journalled within a cylinder A, the revolving blocks H, in combination
with mechanism for holding the circumference of the blocks H, against the
circumference of. the piston D, substantially as and for the purpose specified.
5. A metal plate or disc F placed in the case A, and adjusted by set screws
against the side of the revolving piston, substantially as and for the purpose
specified.