IMPROVEMENTS IN ROTARY ENGINES, PUMPS, AND METERS
Year: 1879

page_text: LETTERS PATENT to Samuel Cleland Davidson, of Belfast, in the County of
Antrim, Ireland, Gentleman, for the Invention of "IMPROVEMENTS IN ROTARY
ENGINES, PUMPS, AND METERS."
Sealed the 13th January 1880, and dated the 22nd July 1879.
PROVISIONAL SPECIFICATION left by the said Samuel Cleland Davidson
at the Office of the Commissioners of Patents on the 22nd July 1879.
SAMUEL CLELAND DAVIDSON, of Belfast, in the County of Antrim, Ireland,
Gentleman. "IMPROVEMENTS IN ROTARY ENGINES, PUMPS, AND METERS."
The improvements relate to the construction, as hereinafter described, of engines,
pumps, and meters to work with a rotary motion.
Or
In the improved engines, pumps, and meters a flat circular disc is used, having
an axle through its centre, on which it rotates, and having a flange or rim at right
angles to and forming a continuous line around its face upon one or both faces.
This flange may be in the form of a circle of less diameter than the disc, in which
case it is placed upon the disc eccentrically in relation to the centre thereof, and
encloses the axle of the disc, but leaves a space between the axle and the nearest
point on the inner side of the flange while the outer side of the flange furthest from
the axle should be within the periphery of the disc, or may coincide with it.
this flange may be elliptical in form, in which case it is so placed upon the disc that
its central point and that of the disc may coincide, and a space be left between
the axle and the two nearest points on the inner side of the flange while the
two furthest points from the axle on the outer side of the flange should be
a little within, or may coincide with the periphery of the disc. Or this flange
may be in the form of a regular curvilinear figure of three or more
enclosing the central part of the disc by a continuous line of alternate convex and
concave curves, in which case the apexes of the outer curves should all either
coincide with or be equidistant from and within the periphery of the disc, and the
apexes of the inner curves should be equidistant from the centre of the disc, and
have a clear space between them and the axle. This flanged disc rotates within a
closely fitting casing circular at the periphery of the disc, flat on the sides, and
having the central space between the axle of the disc and those parts of the flange
nearest to the axle.occupied by a circular boss which is attached to and forms part
D
curves

page_text: of a side of the casing, and is of the same depth as the flange. An annular trough
or pipe with four flat sides is thus formed between this central boss and the outer
parts of the casing-and-when-the-disc-revolves the flange of it passes along through
this trough, the outer surfaces of the flange, which are furthest from the centre-of-
the disc, being in constant contact with the outer side of the trough, and the inner
surfaces, which are nearest the centre, in contact with the inner side, which is
formed by this central boss; and the edges-of the flange are in contact with the
side of the casing. The central boss and the outer part of the casing are recessed
to hold a slide valve which extends across the trough between the recesses.
The
valve is slotted to let the flange of the disc pass through it, and as the valve has
room to slide from side to side to the full extent of the width of the trough, the
disc, when it revolves, causes the flange to slide through this slot; and thereby. to.
inove the valve to and fro.
In order to have the joint between the slot and the flange water tight the slot
is made to hold a cylinder lengthways, the faces of the slot being shaped to fit cor-
rectly to the circumference of the cylinder so far as they enclose it. This cylinder is
slotted lengthways through its centre to fit the flange, and as it is somewhat longer
than the depth of the flange, one end remains solid. The circular motion which
the cylinder has in its socket enables the slot to adjust itself to the altering angles
of the flange in passing through it. With the circular form of flange the slot fits
accurately to the flange throughout on both sides, the opposite sides of the slot
being parallel curves. There is a groove lengthways in the centre of each side of
the slot, in which a slip of iron or other suitable material is placed with a device
such as a spring behind it to keep it pressed against the flange so as to make a
tight joint with the flange, and in order to have a tight joint between the outer
sides of the cylinder and the faces of the socket in which it turns, similar slips
press against the cylinder sides from grooves in the faces of the socket into which
they are inserted.
With the elliptical and other forms of the flange, however, only a portion in the
centre of the opposite sides of the slot through the cylinder is practically parallel,
which portion is all that remains in constant contact with the flange, the rest of
the slot on each side of this portion being more or less sloped away from the side
opposite it.
In this central portion a similar arrangement may be employed for keeping a
tight joint between the slot and flange as that already described; or this portion
of the slot may be somewhat widened and have semi-circular grooves lengthways
on each side with friction rollers to accurately fit into and fill the space between
these grooves and the sides of the flange. To provide for wear in these friction
rollers they are kept pressed forward against the flange by means of a similar
arrangement to that employed for keeping a tight joint between the outer sides of
the large cylinder itself and the socket in which it turns.
Inlet and outlet openings for-the-water-or other fluid to be operated with are
made in the side of the casing on each side of the valve, and the incline planes
formed by the flange of the disc from one side of the trough to the other carry
forward the fluid through the trough from the one opening to the other, where,
upon meeting the valve it is prevented from getting any further along the trough,
and is consequently ejected through the outlet opening in the side of the casing,
and in the casing near this opening an air cushion space may be provided to give
elasticity to the flow of the fluid when being forced with pressure.
If any fluid under pressure be admitted at one of the openings it will force
round the flange and disc to the other opening, causing the axle of the disc to
revolve, from which, conseqnently, motive power may then be obtained.
If the apparatus be adapted as a meter the number of revolutions of the disc as
registered by any suitable counter will indicate the amount of liquid passed
through the apparatus.
When preferred the periphery of the flat disc may be made to coincide all round
with the entire curves of the outer side of the flange, in which case that part of the

page_text: slide valve which is on the outer side of the slot requires to be made deeper, by
the thickness of the disc, than that on the inner side of the slot.
The form of valve herein before described, and the arrangements described for
keeping the joint between the flange and valve tight are those which I propose to
use in my improved engines, pumps, and meters, but it is evident that other forms
and arrangements may be employed in lieu thereof.
When using a disc with flanges on both faces the form of the casing and the
valve arrangement are the same on both sides, as already described, for the side
facing the flange upon a single face of the disc, and the valves may be fastened
together or act independently, as may be preferred. The sides of the casing may be
bolted or otherwise fastened together by any suitable arrangement round the outer
circumference of the casing.

page_text: --the-said-Samuel-Cleland Davidson in the Great Seal Patent Office on the
22nd January 1880.
SAMUEL CLELAND DAVIDSON, of Belfast, in-the-County-of Antrim, Ireland,
Gentleman. "IMPROVEMENTS IN ROTARY ENGINES, PUMPS, AND METERS."
The improvements relate to the construction and arrangement as hereinafter
described of an engine, pump or meter to work with a rotary motion.
In my improved engine, pump or meter I use a flat circular disc having an axle
applied to its centre on which it rotates, and having a cylindrical flange or rim at
right angles to and applied upon one or both faces, which cylindrical flange or rim
I hereinafter call the "disc cylinder."
The disc cylinder is of less diameter than the disc and it is placed npon the disc
eccentrically in relation to the disc centre, and encloses that centre, but leaves a
space between it and the nearest point of the inner side of the disc cylinder, while
that point of the outer side of the cylinder which is furthest from the centre of the
disc should either coincide with or be a little within the periphery of the disc.
The disc cylinder is a fixture to and rotates with the disc inside a closely fitting
casing, which is circular at the periphery of the disc, flat on the sides, and has the
central space between the centre of the disc and that point' of the inner side of the
disc cylinder which is nearest to the disc centre occupied by a circular boss or
cylinder which is attached to and forms part of a side of the casing, and is of
exactly the same depth as the disc cylinder. An annular trough or pipe with
four flat sides is thus formed between this central boss and the outer parts of the
casing, and when the disc revolves, the disc cylinder passes along through this
trough, the outer surface of the disc cylinder furthest from the centre of the disc
being in constant contact with the outer side of the trough, and the inner surface
which is nearest the centre, in contact with the inner side formed by the central
boss, and the edge of the disc cylinder in contact with the side of the casing. The
central boss and the outer part of the casing are recessed to hold a slide valve
which extends across the trough between these recesses. The valve is slotted
across its centre to let the disc cylinder slide through it, but being deeper than
the disc cylinder, the slot is cut into the valve only to the depth of the disc
cylinder, and a part of the slide valve thus remains unslotted. Each end of the
valve has room to slide into its recess to the full extent of the width of the trough,
and as the disc when it revolves causes the disc cylinder to slide along through
this slot the action-of-the-disc-cylinder in the slot causes the valve to move to
and fro.
In order to have the joint between the disc cylinder and the valve water or fluid
tight at this slot, the slot is made to hold a solid cylinder lengthways, the faces of
the slot being shaped to fit correctly to the circumference of the cylinder so far as
they enclose it, and beyond where they so enclose it, the edges of the slot are
chamfered so as to free them from touching the disc cylinder in passing through
at the altering angles due to its eccentricity. The valve cylinder is slotted
lengthways through its centre so as to fit accurately to the disc cylinder, the two
faces of the slot being parallel and concentric, having ares which exactly coincide
with the inner and outer arcs of the disc cylinder. The valve cylinder is somewhat
longer than the depth of the disc cylinder, and as the slot in it is only of the same
depth as the disc cylinder; one end remains solid, and this solid end projects into a
cylindrical recess in the valve at the top of the valve slot, to which this recess
forms a partial continuation.

page_text: This valve cylinder has a circular motion in its socket which enables the slot in
it to adjust itself to the altering angles of the disc cylinder in passing through it.
There is a groove lengthways in the centre of each side of the slot in the valve
cylinder into which is placed a slip of metal or other suitable material, with a
device such as a spring behind it to keep it pressed forward against the sides of the
disc cylinder so as to take up wear and act as packing in maintaining a fluid tight
joint with the sides of the disc cylinder. The faces of these slips should
correspond with the arc of the sides of the disc cylinder against which they act.
The disc cylinder itself at the line of contact between its outer surface and the
outer casing, and between its inner surface and the central boss, should be grooved
and fitted with a similar device to that just described for the slot in the valve
cylinder to maintain a fluid tight joint at these lines of contact. The exposed.
corners of these slips or packing pieces should be slightly chamfered or rounded
off so that they may ride freely into the slot in the valve cylinder.
Inlet and outlet ports or openings for the fluid to be operated with are made in
the side of the casing on each side of the slide valve, and when these openings are
enlarged to the largest area that may be used without allowing communication
with the outlet port to be opened past the diaphragm or partition formed between
the ports by the one half of the disc cylinder, before the other half of the disc
cylinder has interposed itself as a fluid tight partition or diaphragm between the
ports behind the leading partition or diaphragm, these ports will thon form between
them a crescent shaped opening and divided equally by the slide valve, a horn of
the crescent being on each side of the valve.
The fluid to be operated with is carried round through the annular trough from
the one port to the other, when the disc is revolved by means of the curved
diaphragm or partition formed by the disc cylinder between the sides of the
annular trough, and upon meeting with the slide valve partition between the ports,
the fluid is prevented getting any further along the trough, and is consequently
ejected through the outlet port while the. disc cylinder glides through the slide
valve.
If any fluid under pressure be admitted at one of the openings or ports, it will
force round the cylinder and disc to the other port, causing the axle of the disc.
to revolve from which by pulley or other arrangement motion may be transmitted.
If the apparatus be adapted as a meter the capacity of the annular trough being
known, the number of revolutions of the disc as registered by any suitable counter
will indicate the amount of fluid passed through the apparatus. The periphery
of the flat disc may when preferred be made to coincide all round with the outer
side of the disc cylinder, thus forming a cover end to it which would have the
same eccentric motion as the cylinder, in which case that part of the slide valve
and of the valve cylinder upon the outer side of the slot in the valve cylinder
should be deeper by the thickness of the disc than on the inner side of the slot.
The axle of the disc may be applied upon one side of the disc only as exemplified
in the accompanying Drawings, or the shaft may be carried right through and have
bearings on both sides of the casing; but in this case the end of the slide valve
which works in the recess.of the central boss is hollowed, as indicated by the
dotted lines shewn at U, U, in Figure 3, to allow the sides of the slide valve to
slide past on each side of the axle shaft (marked G¹¹ in Figure 3) to the end of its
travel.
The disc may be used with a disc cylinder on both faces, in which case the axle
shaft should be carried right through the casing and have bearings on both sides.
The front plate of the casing marked O" in the Drawings would then be replaced by
another main casing, the same as that marked O, having slide valve and supply and
delivery ports, and these two main casings would be fastened together in the same
manner as shewn for O and O", and the bearings for the axle shaft would be
carried on the back plate to slide valve recess. The faces of the two slide valves
would be separated to the extent of the thickness of the disc upon the two opposite

page_text: faces of which they slide, and this space between the two valves should be filled by
a piece of metal of the same thickness as the disc, and the same width as the faces
-of-the-valves.
When the disc cylinder is so placed upon the disc-that-its-extreme outer edge is
within-the-periphery of the disc, the outer casing enclosing the disc is recessed to
Fexactly-admit as much of the periphery of the disc as projects beyond the extreme
outer point-of- the-disc-cylinder. This is indicated by dotted lines in the accom-
panying Drawings at V, in Figures 4 and 5, the dotted outer line at V of Figure G
indicating the projection-of-the disc periphery beyond the disc cylinder.
The accompanying Drawings illustrate the construction and arrangement of the
apparatus.
Figure 1 is a front elevation shewing in dotted lines the relative positions of the
internal parts. In this Figure the disc cylinder is shewn at the lowest point of its
revolution, in which position the slide valve is also at the lowest point of its travel,
and the disc cylinder so coincides with the outer edges of the inlet and outlet ports,
that it entirely disconnects and shuts off communication between the space enclosed
in the annular trough by the outer side of the disc cylinder and the ports on both
sides of the valve simultaneously. When the disc is revolved so as to bring the
disc cylinder to the highest point of its revolution, and to the position exactly
opposite that indicated in Figure 1, it then so coincides with the inner edges of
both ports that communication is cut off in a similar manner between them and
the space enclosed in the annular trough by the inner side of the disc cylinder.
Figure 2 is a back elevation, and as in Figure 1 the dotted lines indicate the
relative positions of the internal parts. The disc cylinder is here represented at
quarter revolution, in which position the slide valve is at mid distance of its travel,
and on one side of the lines of contact between the disc cylinder and the sides of
the annular trough; the spaces enclosed by the inner and outer sides of the disc
cylinder are simultaneously open to the same port, while on the other side of these
lines of contact the spaces there enclosed are simultaneously open to the opposite
port. Figure 3 is a vertical section on the line A, A, in Figures 4 and 5, shewing
the annular trough formed between the central boss and outer side of the casing;
also the inlet and outlet ports to the same, with section of the slide valve and its
oscillating cylinder through which the disc cylinder slides; and also a section of the
disc cylinder at three quarter revolution. The arrows indicate the direction 'that
the disc is in the present instance presumed to be revolving, but the apparatus will
work equally well in the reverse direction if required, as the action of its parts is
precisely the same in whichever direction the disc is revolved, the direction of the
current only being changed. Figure 4 is a vertical section on the line B, B, in
Figure 3, with the disc cylinder at the same pitch of revolution as shewn therein;
Figure 5 is a horizontal section on the line C, C, in Figures 3 and 4, the disc
cylinder being in the same position as therein indicated; Figure 6 is a plan of the
disc, shewing-the position and eccentricity of the disc cylinder; Figure 7 is a side
view of the slide valve; Figure 8 is a section through the slide-valve-and-valve_
cylinder on the line D, D, in Figure 7.
The letters which indicate the several parts are the same in each Figure, and are
as follows:-
A, A, B, B, C, C, D, D, sectional lines.
E, circular disc.
El, boss on the back of the disc.
F, disc cylinder.
G, axle of the disc.
G¹¹, axle of the disc when continued through to the opposite side of the casing.
TI 1

page_text: U and v, modincations already referred to in the valve and periphery of the
disc.
W, communication passage through the back piece J, J, between the opposite
ends of the valve to let it work in equilibrium.
X, packing slips at the line of contact between the disc cylinder and the inner
and outer sides of the annular trough.
Y, packing slips in the valve cylinder.
It is obvious that when acting as a pump or blowing engine, and the disc is
rotated, and the disc cylinder caused to slide through the slide valve and along the
annular trough, the flow of fluid will be continuous, because exactly as the delivery
decreases from one side of the disc cylinder it increases from the other, and vice
versa, as the revolution continues; and for the same reason, when this apparatus is
used as an engine for giving motive power, the power conveyed is continuous
because the actuating fluid has continuously the same area of the disc cylinder to
act against between the one port and the other, because the half of the disc cylinder
which forms one diaphragm or partition across the annular trough moves in
equilibrium across the port while the other diaphragm or partition is being acted
upon between the ports, and only comes into action at the moment that it itself
shuts off communication between the supply port and the other diaphragm.
The disc E is kept in contact with the face of the central boss N by means of
the packing at T, which packing can be pressed forward as required by means of
the screw adjustment gland R which can be secured in the requisite position by
means of the check nut S.
The face of the slide valve is kept in contact with the disc face by means of the
adjustment screws L which act upon the back piece J of the valve and press it and
the valve forward as required.
The following advantages may be mentioned as pertaining to the hereinbefore
described apparatus:
First. That the rotary motion of the disc and disc cylinder is continuous in
whichever direction it is required, and is direct acting upon the axle shaft.
Second. That a perfectly fluid tight joint can be established between the disc
cylinder and the slot in the oscillating cylinder of the slide valve, because the disc
cylinder though revolving eccentrically presents within the slot of the valve
cylinder an arc of uniform curve at all points of its revolution, and the sides of the
slot can without difficulty be made to coincide accurately with this arc while they
have a considerable width of bearing against the sides of the disc cylinder.
Third. That both the inner and outer sides of the disc cylinder act as propelling
surfaces in relation to the fluid operated with.
Fourth. That as the action and working of the disc cylinder and slide valve are
precisely the same in whichever direction the disc is revolved (only the direction of
the current being changed) the apparatus may therefore be reversed on reversing
the order and operation of the supply and delivery ports.
Having now described the nature of my improvements in rotary engines, pumps,

page_text: and meters, and the means of carrying same into effect, I declare that I claim as
my Invention,—
The general combination, arrangement, and construction-of-the-parts-composing-
the apparatus, all substantially as hereinbefore described and represented in the
accompanying Drawings.
In witness whereof, I, the said Samuel Cleland Davidson, have hereunto set
my hand and seal, this Seventeenth day of January, One thousand eight
hundred and sichto