Improvements in Rotary Engines.
Year: 1887

page_text: Date of Application, 9th Dec., 1887
Complete Specification Left, 10th Sept., 1888
Complete Specification Accepted, 7th Dec., 1888
Improvements in Rotary Engines.
I, CHARLES GRIFFIN of 22 Garrick Street Covent Garden in the County of
Middlesex, Chemical and Philosophical Instrument Maker do bereby declare the nature
of this invention to be as follows:-
My invention is applicable to engines consisting of a cylindrical casing with an axis
passing centrally through the casing. The axis carries a cylindrical block set eccen-
trically upon it; on one side the block touches the periphery of the casing and here it
fits the casing steam tight but on the other side and elsewhere in consequence of the
eccentricity of the block a space is left between it and the casing and this space con-
stitutes the working chamber. The casing is pierced with two ports or passages one
for the admission of the steam and one for the exit and between the two ports there is
a flap jointed which divides the working chamber into two parts. The block is driven
round within the casing the flap being always in steam tight contact with it following
the movement of the block. The steam engine is made compound with three or other
number of compartments and the steam is expanded from compartment to compart-
ment. The details of the engine may be much varied as respects the form of the
casing and the block and either may be the revolving part; so also either may carry
the flap which divides the working chamber. Two or more flaps may be used in each
chamber for reversing &c. But the essential features of the invention relate to the use
of revolving walls to avoid friction and leakage and to the construction and arrange-
ment of this flap; it is formed with two arms or parts and the pressure of the steam
on one arm or part merely balances that on the other arm or part or the steam is
permitted to press on only a part of one arm. In this way much friction is avoided
and the flap is allowed to bear on the surface against which it closes with no more
pressure than is requisite to form a steam tight joint. More than one flap may be
used in each chamber.

page_text: The valve for admitting steam to the high pressure cylinder may be a disc of metal
rotating with the shaft almost steam tight in a chamber where it is kept in a central
position by thin distance pieces. A circular slot is cut in this disc extending over the
are of the circle through which it is desired steam shall be admitted. The disc having
steam on both sides is in equilibrium.
A valve in the form of a revolving tube having ports pierced in it may also
be used.
The following describes one form in which I construct rotary engines:-the engine
is a compound engine, it has a high pressure compartment and a low pressure com-
partment, either one or more. Assuming that two compartments only are employed;
the arrangements in respect to these two compartments are similar with the exception
that the low pressure compartment is of larger capacity than the high. The main
shaft or axis of the engine passes through both compartments and two cylindrical
blocks are fixed upon it, one occupying each compartment. The thickness of the
block corresponds to the width of the compartment, and the ends of the block fit in
steam tight contact against the end walls of the compartment. These walls revolve
with the block. The periphery of the cylindrical block touches the side of the com-
partment at one point and here a steam tight abutment packing is provided; at all
other points there is a space between the periphery of the block and the side wall of
the compartment-this is the working space to receive the steam.
For half the circumference the walls of the compartment are concentric with the
main shaft or axis and here the working space is at its full width; this width is
diminished as the abutment is approached. Thus the interior form of the compart-
ment is truly cylindrical for half of its circumference, the half which is not cylindrical
is of easy curvature. The working compartment may be made cylindrical and set
eccentric to the shaft; this is less advantageous but simpler in construction. The
cylindrical block carries a flap or valve and as the block together with the shaft
revolves one extremity of the flap or valve rests in steam tight contact with the peri-
phery of the compartment. It is by the admission of steam to the capacity between
the abutment and this flap that rotary motion is produced.
The flap or valve is nearly in equilibrium, that is to say, the pressure of the steam
upon the part which bears against the periphery of the compartment is so far balanced
that the contact between the parts is light, no more than is necessary to insure the
steam tight closing. This flap is in effect a moveable portion of the periphery of the
cylindrical block and is fixed to a cylindrical boss which fits a corresponding cavity in
the main portion of the block or is projected at both ends and carried in seats formed
for it in the revolving walls. The block is also recessed so that the flap is free to rock
sufficiently far to allow its outer end to remain in contact with the sides of the working
compartment throughout the entire revolution. The steam to drive the engine is
admitted first to a cavity in one of the end covers of the working compartment sur-
rounding or partially surrounding the shaft. In order that the pressure may be
balanced upon the two sides of the block there is a similar cavity on the other side in
connection with the first. From these cavities the steam passes by a passage in the
block to its periphery at the point immediately in rear of the outer end of the move-
able flap. The steam is also admitted behind the inner end of the flap to act in the
cavity in the block in which the flap is housed so that the steam acts simultaneously
to press both ends of the flap but the outer end being somewhat longer the pressure on
it proponderates and this end of the flap is thus held against the walls of the working
compartment. The outlet for the steam is either through the block to the cylinder
cover, or in the side of the working compartment and close to the abutment, and as the
flap comes round it passes over the outlet. The admission of steam arrested at any
desired period of the revolution in consequence of the end of the steam passage in the
block no longer coinciding with the cavity in the cover from which it is fed.
The form of the working chamber causes the flap to close in to the block in passing
the abutment.
The steam from the high pressure compartment passes into the low pressure com-
partment in which it is expanded and made to work upon a flap of larger area.

page_text: Whenever possible in place of separating the two working compartments by a fixed
partition I do so by means of a disc fixed upon the axis and revolving with it, its edge
may or may not enter a groove formed all round the casing.
The steam passes directly from one compartment to another by an aperture or
passage either through the disc or over its edge immediately in front of one flap or
valve and in rear of the other.
In the covers similar steam cavities are formed so that the end thrust on the shaft is
balanced, from these cavities steam is drawn to supply the engine; and sometimes to
the space behind the flap at the moment when the flap should open out from the block.
The working steam afterwards suffices to keep the flap in place and to balance, as far
as is desirable, the pressure upon it.
•
Dated this 9th day of December 1887.
CARPMAEL & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Rotary Engines.
I, CHARLES GRIFFIN, of 22 Garrick Street, Covent Garden, in the County of
Middlesex, Chemical and Philosophical Instrument Maker, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
My invention is applicable to engines consisting of a cylindrical casing with an axis
passing centrally through the casing. The axis carries a cylindrical block set
eccentrically upon it, on one side the block touches the periphery of the casing and
here it fits the casing steam tight but on the other side and elsewhere in consequence
of the eccentricity of the block a space is left between it and the casing and this space
constitutes the working chamber. The casing is pierced with two ports or passages
one for the admission of the steam and one for the exit and between the two ports
there is a flap jointed which divides the working chamber into two parts. The block
is driven round within the casing, the flap being always in steam tight contact with
it following the movement of the block. This flap is formed with two arms or parts
and the pressure of the steam on one arm or part nearly balances that on the other
arm or part. In this way much friction is avoided and the flap is allowed to bear on
the surface against which it closes with no more pressure than is requisite to form a
steam tight joint.

page_text: Another form of my engine is as follows:-
The main shaft or axis of the engine has cylindrical blocks fixed upon it, one
occupying each compartment of a surrounding casing. The thickness of the block
corresponds to the width of the compartment and the ends of the block fit in steam
tight contact against the end walls of the compartment. These walls revolve with the
block. In each case the periphery of the cylindrical block touches the side of the.
compartment at one point and here a steam tight abutment packing is provided; at
all other points there is a space between the periphery of the block and the side wall
of the compartment-this is the working space to receive the steam.
The
The working compartment is cylindrical and set eccentric to the shaft.
cylindrical block carries a flap or valve and as the block together with the shaft
revolves one extremity of the flap or valve rests in steam tight contact with the
periphery of the compartment. It is by the admission of steam to the capacity
between the abutment and this flap that rotary motion is produced...
The flap or valve has two arms and is nearly in equilibrium, that is to say, the
pressure of the steam upon the part which bears against the periphery of the com-
partment is so far balanced that the contact is light, no more than is necessary to
insure the steam tight closing. This flap is free to rock sufficiently far to allow its
outer end to remain in contact with the sides of the working compartment throughout
the entire revolution. The steam to drive the engine is admitted first to a cavity in
one of the end covers of the working compartment surrounding or partially
surrounding the shaft. The steam passes by a passage in the block to the rear of the
moveable flap. The steam acts simultaneously to press both ends of the flap but the
outer end being somewhat longor the pressure on it preponderates and this end of
the flap is thus held against the walls of the working compartment. The outlet for
the steam is in the side of the working compartment and as the flap comes round, it
passes over this outlet. The admission of steam is arrested at any desired period of
the revolution in consequence of the end of the steam passage in the block no longer
coinciding with the cavity in the cover from which it is fed.
Whenever possible in place of separating two working compartments by a fixed
partition I do so by means of a disc fixed upon the axis and revolving with it.
In the covers similar steam cavities are formed so that the end thrust on the shaft
is balanced.
In order that my said invention may be more fully understood and readily carried
into effect will proceed to describe the drawings hereunto annexed.
Figure 1 is a transverse section of an engine constructed in accordance with my
invention and illustrates one method of construction.
Figuro 2 is a longitudinal section and Figure 3 is a transverse section illustrating
another arrangement.
The section Figure 3 is taken on the line 3, 3, in Figure 2.
Figure 4 shows the inner side of one of the end covers of this engine.
In Figure 1 A is the main shaft, on it there is fixed a cylindrical block B eccentric
to the axis A-The block is contained within a cylindrical casing C concentric with
the axis-On one side of this casing a chamber D is formed and in the chamber a
flap E works. F is the steam inlet and G is the exit aperture. The steam entering
at F exerts its pressure on both the arms of the flap E which is consequently nearly
in equilibrium and only bears with a light pressure upon the periphery of the
block B. The pressure of the steam being exerted on one side of the block B only,
this tends to move the block around within the chamber C, thereby driving the main
shaft. I make this engine compound, that is to say, I lead the steam from the exit
aperture at G into another working chamber similar to the first and containing an
eccentric block also mounted on the main shaft A. The parts relating to this second
working chamber are indicated by dotted lines.
I may thus employ several working chambers all containing blocks mounted upon

page_text: the same main shaft. The chambers are separated the one from the other by rotating
walls, as is fully described in respect to Figures 2, 3 and 4.
The form of the flap E may be varied, the effect will remain the same whatever the
form so long as one of the arms or parts bears on the block whilst the other passes
steam tight along a surface concentric with the axis of the flap.
In Figures 2, 3 and 4, I is the main shaft and K is the casing. The main shaft
passes through bearings on the end covers of the casing and within the casing the
shaft carries the concentric cylindrical blocks L, L, L³, L. These blocks are
contained in the chambers M1, M2, M3, M4, of the casing. These chambers are
cylindrical but they are not concentric with the axis. The centre of the working
chamber M' is below the axis, whilst the centre of the chamber M2 is above it, and so
the chambers are arranged alternately. In Figure 2 four chambers are shown, and
the steam spaces are shaded with lines. In the engine represented by the Figures 2,
3 and 4, each chamber is designed to receive steam direct from the boiler but in
practice I prefer to make these engines compound, that is to say, I cause the
steam from the first working chamber to pass into a second chamber of larger
capacity.
The working chambers are separated the one from the other by walls consisting of
rings N within which discs N¹ carried upon the main shaft revolve. The discs N'
are grooved, and hard metal rings are inserted into the grooves and extend around
their periphery. These rings run in and against steel linings. Thus a steam tight
separation is made between the chambers. I call these partitions between the
chambers" revolving walls." 0, 0, are spring abutments, one is provided in each
chamber to press against the block and form a steam tight joint at that part where
the periphery of the block meets the wall of the chamber.
Steam is supplied to the engine by the pipes P and is delivered into cavities in both
of the end covers of the casing, thus the end thrust on the shaft is balanced.
The steam issues from the cover by passages or ports Q1, Q2; around these ports
packing pieces are provided to form steam tight joints with the discs N*, N*, which
rotate nearly in contact with the covers. Through each of these discs there are two
circular passages N** N***, which are continued into the block L' or L as the case
may be. The passages are so placed that, during the rotation of the disc N*, one of
them comes at a certain part of the revolution to correspond with the port Q¹ whilst
the other at the same time corresponds with the port Q. Thus the port Q in the left
hand cover supplies steam to the block L' and its chamber M', whilst the port Qin the
same cover similarly supplies steam to the block L2 and the chamber M. The steam
passage N*** in this latter case being prolonged through the block L¹ and the
revolving wall N¹ beyond.
The steam from the port Q¹ enters by the passage N** into a cavity R' in which
the double flap R works-This flap turns upon a spindle R² and it is provided with
packing pieces so that one of its arms forms a steam tight joint against the sides of
the cavity in the block and the other against the interior of the casing K.
The arrangement of the flap is similar as respects each of the blocks L¹·L² L³ Lª.
The steam cominences to enter the working chamber as soon as the flap R passes the
abutment O; the form of the chamber permits the flap to then open out from the
block and the steam issues into the working chamber and it continues to enter this
chamber so long as the port Q corresponds with the mouth of the passage N** but
when this passage passes away from the port the steam is cut off and the rest of the
rotation is performed by the expansion of the steam, which is retained in the working
chamber until the flap I reaches a series of slots or apertures in the side of the
working chamber at S, and then the steam escapes into the outlet T.
The form of the flap may be varied as already explained.
In the case of a compound engine the steam so escaping would be led back to
perform work in another chamber or chambers.
U, U, are small passages bored in the parts L', N¹, etc. to admit steam merely for
the purpose of starting the engine, the passages communicate with an annular groove
in the end cover to which steam can be admitted by opening the stop-cock V.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a rotary engine the use substantially as described of a balanced flap R having
two arms on which the steam presses but with a slight preponderance to prevent the
direct passage of steam from the inlet to the outlet side of the engine.
2. In a rotary engine the use substantially as described of a balanced flap having
two arms or parts one passing steam tight along a surface concentric with the axis
of the flap and the other bearing upon the surface with which the flap is required to
make contact and which surface is in movement relatively to the part which carries
the flap.
3. In a rotary engine the separation of the working chambers the one from the
other by rotating walls substantially as described.
4. In a rotary engine having several working chambers traversed by a main shaft
admitting steam from opposite ends of the engine in such manner as to balance the
endwise pressure upon the shaft.
5. In a rotary engine having several working chambers traversed by a main shaft
admitting steam simultaneously to two chambers diametrically opposite so as to balance
the pressure upon the bearings of the shaft.
6. A rotary engine substantially as described in respect to Figure 1 of the annexed
drawings.
7. A rotary engine substantially as described in respect to Figures 2, 3 and 4 of
the annexed drawings.