Improvements in Rotary Engines for Steam or Air.
Year: 1891

page_text: Date of Application, 18th Nov., 1891
Complete Specification Left, 17th Sept., 1892-Accepted, 22nd Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements in Rotary Engines for Steam or Air.
I, JOHN JOHNSTON of 13 Elliot Street, Glasgow, in the County of Lanark,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to the manner in which I construct and arrange a rotary
steam engine or compressed air engine whereby I am enabled to readily vary the
cut off upon the inlet to the cylinder or cylinders of such engines and at the same
time to produce a simple and advantageous arrangement of parts for giving motion
to the main shaft or central axis.
.
In carrying my invention into effect I arrange my cylinder when employing only
one cylinder for my engine with each end open and provided with flanges for the
attachment of covers. I pass through the cylinder a shaft carrying a circular
piston having upon it a number of blades fitting into longitudinal grooves or
channels. These channels or grooves I lead into end openings or ports which I
form at one or both of the ends of my cylinder; and I construct my sliding blades
or vanes upon the piston so that they may be free to move outwards when the steam
is admitted into the groove beneath them, and although pressed outwards by the
pressure of the steam I cause a free passage for the steam to be provided along the
side or front surface of the blade, so that the steam when outside the circumference
of the piston may act upon the projecting blade and thus cause it to carry round
the piston to which it is attached.
The piston shaft or main shaft I mount eccentrically with the cylinder so that at
one part of the cylinder the outer surface of the piston and the inner surface of
cylinder are in contact; and at this position I allow the blades or vanes to be flush
with the outside of the piston and close pressed down within their grooves or
chambers. Upon the front side of the blades or vanes I form channels or passages
for permitting the escape of the steam from the slot to the projecting portion of the
blades, which projecting portion increases in extent up to the centre line of the
cylinder and then in like manner and extent decreases until the upper position is
again reached, owing to the eccentricity of the piston within the cylinder. Along
the upper portion of the cylinder 1 place packing strips or layers of metallic packing
or other suitable material to prevent the escape of the steam from the pressure to
the exhaust side of the cylinder; the exhaust side being of necessity opposite to
the steam side and is provided with any suitable flange or outlet branch.
The cylinder covers I cause to rotate with the piston being attached thereto by
screws, cotters or other ordinary.fastenings, and I keep them steam tight against
the faces of the ends of the cylinder by packing rings of conical form preferably
for permitting of easy adjustment, or by any well known system of packing material
suitable for such a purpose. The packing strips along the cylinder I also provide
with adjustable screw connections having springs in some cases acting between them
for greater security. The valve I arrange upon the end of my piston shaft or cover
so that as it rotates it may bring one or the other of the ports which I form within
it opposite to the steam pipe opening or inlet in such a manner that the steam will
pass from the ports to push out the piston slides or blades and also escape to push
forward the blades within the cylinder. I cause the steam ports to be open to the
steam by means of an inlet pipe and also by means of a channel which I form
within the valve box, thus permitting the steam to be upon the piston for the full
revolution of the piston if desired. I do not arrange my piston to receive full
steam when providing for large areas or economical working, but I mount a slide
of circular configuration around one side of my valve box which I cause to move
more or less round the valve port area by means of adjusting screws and nuts, so

page_text: that any desired cut off may be provided for and obtained without removing any of
the working parts or interfering with the movement of the engine shaft.
I arrange packing strips or pads of packing to keep the valve slipper or apron
tightly in position, and I sometimes provide hand levers and links instead of screws
for obtaining the desired adjustment.
I pack the end valve gudgeon with any suitable packing introduced through
stuffing boxes of any desired description. And I support the slides or blades
within the end covers by means of channels or grooves to suit the width and
movement of the slides.
I employ ny improvements with slightly altered proportions of ports and
passages to suit compressed air instead of steam as a motor, and I mount the
axle or shaft within bearings or journals, and within frames of any ordinary kind.
Dated this 17th day of November 1891.
CLERK & MARKS,
13, Temple Street, Birmingham, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Rotary Engines for Steam or Air.
I, JOHN JOHNSTON, of 13 Elliot Street, Glasgow, in the County of Lanark,
Engineer, 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 :-
This invention relates to the manner in which I construct and arrange a rotary
steam engine or compressed air engine whereby I am enabled to readily vary the
cut off upon the inlet to the cylinder or cylinders of such engines and at the same
time to produce a simple and advantageous arrangement of parts for giving motion
to the main shaft or central axis.
In carrying my invention into effect I arrange my cylinder, when employing only
one cylinder for my engine, with each end open and provided with flanges for the
attachment of covers.
In the two accompanying sheets of explanatory drawings to be hereinafter
referred to-
Figure 1 is an end elevation of my improved engine.
Figure 2 is a part side elevation showing the valve box.
Figure 3 is a detailed enlarged part elevation of one of my revolving covers, and
Figure 4 is a sectional plan of the same on the line x, y.
Figure 5 is an end clevation of my revolving circular or drum piston.
Figure 6 is a transverse section through my motor cylinder showing the piston
with its slides or blades in position and showing the exhaust port.
Figure 7 is a longitudinal section through the cylinder and valve box showing
steam inlet.
Figure 8 is a transverse section through the valve box.
Figure 9 is an enlarged detail elevation of the slide or blade showing side jointing
arrangement, and Figure 10 is a plan of the same.
I pass through the cylinder A. a shaft B carrying a circular piston or drum
piston C having upon it a number of blades D, D', D', fitting into longitudinal
grooves or channels E, E, E2. These channels or grooves I lead into end openings
or ports which I form at one or both of the ends of my cylinder; and I construct
my sliding blades or vanes upon the piston so that they may be free to move out-
wards when the steam is admitted into the groove beneath them, and although
pressed outwards by the pressure of the steam I cause a free passage d, d, for
the steam to be provided along the side or front surface of the blade, so that the
steam when outside the circumference of the piston may act upon the projecting
blade and thus cause it to carry round the piston to which it is attached, the motion
of the piston being in the direction indicated by the arrow in Figure 6.

page_text: The piston shaft or main shaft B I mount eccentrically with the cylinder A so
that at one part A' of the cylinder the outer surface of the piston C and the inner
surface of cylinder are in contact; and at this position A' I allow the blades or
vanes D to be flush with the outside of the piston and close pressed down within
their grooves or chambers E. Upon the front side of the blades or vanes D I form
channels or passages such as d for permitting the escape of the steam from the
port to the projecting portion of the blades, which projecting portion
increases in extent up to the centre line of the cylinder and then in like
manner and extent decreases until the upper position A¹ is again reached,
owing to the eccentricity of the piston within the cylinder. Along the upper
portion of the cylinder at A' I place packing strips or layers of metallic
packing G or other suitable material to prevent the escape of the steam from the
pressure A to the exhaust side A³ of the cylinder; the exhaust side A³ being of
necessity opposite to the steam side and is provided with any suitable flange or
outlet branch a³.
The cylinder covers H I cause to rotate with the piston C being attached
thereto by screws, cotters or other ordinary fastenings, and I keep them steam
tight against the faces of the ends of the cylinder by packing rings K of conical
form preferably for permitting of easy adjustment or by any well known system
of packing material suitable for such a purpose. The packing strips and rings
along the cylinder I also provide with adjustable screws or connections having
springs in some cases acting between them for greater security. The valve LI
form or arrange upon the end of my piston shaft B or cover H so that as it rotates
it may bring one or the other of the ports F, F, F which I form within it opposite
to the steam pipe opening or inlet M in such a manner that the steam will pass
from the ports to push out the piston slides or blades and also escape to push
forward the blades within the cylinder. I cause the steam ports to be open to
the steam by means of an inlet pipe M and also by means of a channel n which I
form within the valve box N, thus permitting the steam to be upon the piston for
the full revolution of the piston if desired. I do not arrange my piston to receive
full steam when providing for large areas or economical working, but I mount a
slide of circular configuration around one side of my valve box which I cause to
move more or less round the valve port area by means of adjusting screws and
nuts P, so that any desired cut off may be provided for and obtained without
removing any of the working parts or interfering with the movement of the engine
shaft.
I arrange packing strips or pads of packing O' to keep the valve slipper
or apron O tightly in position, and I sometimes provide hand levers and links
instead of screws for obtaining the desired adjustment.
pack the end valve gudgeon with any suitable packings Rintroduced through
stuffing boxes and glands S of any desired description. And I support the slides
or blades within the end covers by means of channels or grooves H' to suit the width
and movement of the slides D, D1, D2. I affix plates T at each end of the blades D
which plates enter a groove T¹ in the face of the cylinder, so that when the steam
pressure is cut off the blades D may be kept up to the face of the cylinder and the
packing until steam is again admitted behind the blades. To prevent leakage of
steam between the slides and the grooves in the cylinder covers I arrange packing
strips U in grooves U which are kept in position by the steam pressing them
against the face as shown in Figures 9 and 10.
I employ my improvements with slightly altered proportions of ports and passages
to suit compressed air instead of steam as a motor, and I mount the axle or shaft
within bearings or journals, and within frames of any ordinary kind.
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. The construction and arrangement of steam compressed air and other motor

page_text: engines having cylinders and pistons with sliding blades, and valves and ports,
substantially as and for the purposes hereinbefore described, and as illustrated in
the accompanying drawings.
2. In a steam or other motive power engine, the application and arrangement of
sliding blades D, D1, D2 within a circular piston C working within a cylinder such
as A, substantially as and for the purposes hereinbefore described and as illustrated
in the accompanying drawings.
3. In a steam or other motive power engine, the construction and arrangement
of a valve box or chamber such as N, having a sliding or adjustable cut off apron
such as O, substantially as hereinbefore described and as illustrated in the
accompanying drawings..
Dated this 16th day of September 1899
CLERK & MARKS,
13, Temple Street, Birmingham, Agents for the Applicant.