IMPROVEMENTS IN STEAM ENGINES, WHICH ARE ALSO APPLICABLE TO PUMPS
Year: 1852

page_text: LETTERS PATENT to Thomas Elliott, of Stockton-on-Tees, in the
County of Durham, Engineer, for the Invention of "IMPROVEMENTS
Desenail
Sealed the 9th March 1853, and dated the 18th December 1852.
PROVISIONAL SPECIFICATION left by the said Thomas Elliott at
the Office of the Commissioners of Patents, with his Petition,
on the 18th December 1852.
I, THOMAS ELLIOTT, of Stockton on Tees, in the County of Durham,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM ENGINES, WHICH ARE ALSO APPLICABLE TO PUMPS,"
to be as follows:-
I make use of a casing, of the peculiar shape shewn in the annexed
Figure, with an ingress and egress port at A, and B.
In this casing revolve two pistons, of the elliptical shape shewn,
and which are always in contact at one particular point during their
revolution.
The casing and pistons, applied to pumps, will be highly efficient
for the raising and forcing of fluids.

page_text: SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said Thomas Elliott in the Great Seal
Patent Office on the 18th June 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS ELLIOTT, of Stockton on Tees, in the County of Durham,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of December,
in the year of our Lord One thousand eight hundred and fifty-two,
in the sixteenth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Thomas Elliott, Her
special licence that I, the said Thomas Elliott, my executors, admi-
nistrators, and assigns, or such others as I, the said Thomas
Elliott, my executors," administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVEMENTS IN STEAM ENGINES, WHICH ARE
ALSO APPLICABLE TO PUMPS," upon the condition (amongst others)
that I, the said Thomas Elliott, by an instrument in writing under
iny hand and seal, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Elliott, do hereby
declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and
ascertained in and by the following statement thereof, reference
being had to the Drawings hereunto annexed (that is to say):
My Invention consists of an improved construction of rotary
engine, which is also applicable to pumping and forcing liquids, air,
and
gases. The peculiar feature of my improved engine is, that the

page_text: power is obtained by the action of the motive medium on two
elliptical pistons of equal dimensions, placed with their similar axes
at right angles to each other, and revolving in this relation in a
casing or cylinder, the internal configuration of which is such that,
while the pistons are in all their positions in contact with each other,
at one point or line throughout their entire length, their sides are
also in constant contact with the interior of the casing or cylinder,
the pistons acting as abutments to each other, and revolving consc-
quently in opposite directions.
Figures 1, 2, and 3, of the Drawings annexed are different views
of the engine; Figure 1, being a sectional clevation; Figure 2, a
vertical section on the line Z, Z, of Figure 3; and Figure 3,
an end
elevation of the same. The latter Figure shews, also, the method
which I prefer to adopt, of coupling the piston shafts without spur
gearing. D, is the cylinder or casing, which is of the peculiar shape
shewn, the interior being truly bored out, so that the pistons may
work in accurate contact with it. A, and B, are the ports for the
induction and eduction of the motive medium, either of which may
be used as the induction port, according to the direction in which
the engine is required to work. C, C, are the pistons, which are of
an elliptical form, the longer or transverse axis of each being equal
in length to the diameter of the circular portion of the casing D, in
which it revolves, and the curve of the sides such that constant
contact shall be preserved between the pistons on one line or point.
during their revolution, regard being always had to the placing them
with their similar axes at right angles to each other, as shewn by
the dotted lines in Figure 3. E, E, are packing pieces, inserted in
the ends of the pistons. J, J, are the shafts on which the pistons are
fixed and revolve. H, H, are the side packings for the pistons, which
are kept in contact with them by the pressure of steam, water, or
other fluid admitted between the plates H, H, and the side covers
of the cylinder or casing R, R. S, S, arc rings of india rubber,
which are placed round the edges of the packings H, H, to keep.
them steam, or air, or fluid tight. Q, Q, are stuffing boxes, to keep
the spaces between the packings H, H, and the side covers R, R,

page_text: steam tight. The ends of the shafts J, J, pass through the packing
plates H, H, which may either be cast with collars to receive the
ends of the shafts, or inay be formed with loose collars, bushed with
brass, or other suitable metal, for the same purpose. The piston
shafts may be coupled together, so as to keep the pistons in their
proper relative positions, by means of spur gearing at both ends, or
at one end only, the other end being in such case provided with an
arrangement of coupling gearing, such as is shewn in Figure 3, (an
arrangement which might be adopted at both ends of the pistons if
preferred). In this Figure J, J, are the piston shafts; K, K, cranks
on the ends of these shafts, placed at right angles to each other;
L, L, a bell crank, with arms of equal length, which is centred on the
pin or stud N. The crank pins of the cranks K, K, and bell crank
L, L, work in the brasses M, M, which are attached to the ends of
the connecting rods, P, P, by which the cranks K, K, and bell crank
L, L, are connected. The shafts being thus coupled together, the
motion may be taken off from either of them at either side of the
engine, as may be most convenient. G, is the slide, or regulator,
for the admission of the motive medium to the cylinder, or casing
D; and F, its spindle. I is the exhaust pipe; and O, O, the steam
pipe and valve casing.
The operation of the engine is as follows:-On steam being ad-
mitted through either of the ports, say A, to the cylinder or casing,
it will act against the surfaces of the two pistons C, C, which, being
in contact, serve as abutments to each other, and cause them to
revolve in the direction of the arrows, the pistons moving in opposite
directions, and, owing to their peculiar form, maintaining constant
contact with each other. When the direction of motion is required
to be reversed, the handle of the slide G, is shifted, so as to make
the eduction port the induction port for the time being; the steam
will then be admitted on the opposite side of the pistons, and motion
will consequently be given to them in the reverse direction to that
in which they had been previously revolving. The engine is also
capable of being worked by other motive agents than steam, such
as air, gases, and fluids. It may also be employed as an air pump

page_text: for steam engines, and for pumping purposes generally, and, in such
case, may be made to serve the purpose of a meter, and indicate the
quantity of fluid passing through it, by connecting one of the piston
shafts with a train of wheel work suitably arranged to correspond
with the working capacity of the cylinder or casing.
And having now described the nature of my said Invention, and
in what manner the same is to be performed, I declare that what I
clain, in respect thereof, is,-
First, the construction of rotary engines with two elliptical
pistons revolving in contact with and at right angles to each other
in a suitable cylinder or casing, as represented in the Drawings and
herein before described.
Second, the mode of packing the sides of the pistons of such
rotary engines as represented in Figure 2, and herein-before described.
Third, the mode of coupling the ends of the piston shafts of
such rotary engines, as represented in Figure 3, and herein-before
described. And,
Fourth, the application of the said modes of construction to
pumps for raising, forcing, and exhausting fluids, air and gases, as
before described.
In witness whereof, I, the said Thomas Elliott, have here-
unto set my hand and seal, this Sixth day of June, One
thousand eight hundred and fifty-three.
THOMAS ELLIOTT. (L.S.)