IMPROVEMENTS IN ROTATORY MOTIVE-POWER PUMPING AND MEASURING APPARATUS
Year: 1869

page_text: LETTERS PATENT to James Angelo McElroy, of Glasgow, in the
County of Lanark, North Britain, Engineer, for the Invention of
"IMPROVEMENTS IN ROTATORY MOTIVE-POWER PUMPING AND MEASURING
APPARATUS."
Sealed the 3rd September 1869, and dated the 8th March 1869.
PROVISIONAL SPECIFICATION left by the said James Angelo McElroy
at the Office of the Commissioners of Patents, with his Petition,
on the 8th March 1869.
I, JAMES ANGELO MCELROY, of Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN ROTATORY MOTIVE-POWER PUMPING AND MEASURING
APPARATUS," to be as follows, that is to say :-
This Invention relates to improved rotatory apparatus to be used for
obtaining motive power by means of steam, or other fluid, for pumping,
and for measuring fluids.

page_text: The improved apparatus comprises a cylindrical chamber, having
within it an elliptical or approximately elliptical boss or drum fixed
eccentrically on a central shaft, extending out through stuffing boxes
in the ends of the chamber. The boss touches the cylindrical surface
of the chamber, and has a strip of metallic packing applied at the
point of contact, whilst it revolves like a piston. There are two
abutments or sliding stops which are opposite to each other in the same
diametrical line, and which extending out through stuffing boxes are
connected together by external rods, so as to work together, and so that
as one is pushed out by the action of the eccentric elliptical boss it
causes the other one to move inwards, the inner ends of the two stops
being always in contact with the boss. The elliptical boss is so fixed
on the shaft that the centre of the latter is in a point of the shorter axis
wherein a straight line equal to the shorter axis, but placed at right
angles thereto, has its ends exactly in the circumference. Such a point
can be taken in any ellipse, but it is preferred to take an ellipse of about
such proportions as that if the shorter axis is divided into seven equal
parts the point fulfilling the conditions will be at the distance of two of
those parts from one end. Then all straight lines drawn through that
point and having their ends in the elliptical circumference will be equal
or very nearly so, and the two sliding stops will in consequence be kept
at a practically uniform distance apart. The shaft is made tubular
and the fluid enters by one end and passes off by the other, being led
by passages formed in the elliptical boss to suitable points on the cir-
cumference thereof, and which passages are shaped spirally so as to
deliver the fluid in a tangential direction.
Instead of the chamber being fixed and the shaft revolving, the shaft
may be fixed whilst the chamber revolves on it, or both parts may be
arranged to revolve in opposite directions or at different velocities.
Plates turned to accurately fit inside the cylindrical chamber are used
for packing the ends thereof, and are adjusted by means of the
stuffing boxes, which are arranged to be screwed to the external end
covers.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said. James Angelo Me Elroy in the Great Scal Patent
Office on the 7th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
ANGELO MCELROY, of Glasgow, in the County of Lanark, North Britain,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of March, in the
year of our Lord One thousand cight hundred and sixty-nine, in tlie
thirty-second year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said James Angelo McElroy,
Her special licence that I, the said James Angelo McElroy, my
executors, administrators, and assigns, or such others as I, the said
James Angelo McElroy, 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 ROTATORY MOTIVE-POWER PUMPING
AND MEASURING APPARATUS," upon the condition (amongst others) that
I,. the said James Angelo McElroy, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and scals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, aud
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 James Angelo McElroy,. 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 in writing, reference being had to the.
accompanying Drawings, that is to say:-
My said Invention relates to improved rotatory apparatus to be used
for. obtaining motive power by means of steam or other. fluid, for.
pumping, and for measuring fluids.

page_text: And in order that my said Invention, and the manner of performing
the same, may be properly understood, I have hereunto appended a
Sheet of explanatory Drawings to be herein-after referred to and repre-
senting my improved apparatus arranged as a steam engine.
Figures 1 and 2 are vertical sections as at right angles to each
other.
The apparatus comprises a cylindrical chamber 1, formed by a flanged
cylindrical casting 2, to which end covers 3, 4, are bolted, and which
is formed with feet 5, whereby it is bolted down to a bed frame 6.
Inside the chamber 1, there is an elliptical or approximately
elliptical boss or drum 7, fixed eccentrically on a central shaft 8,
extending out through stuffing boxes in the end covers 3, 4. The boss 7
touches the cylindrical surface of the chamber, and has a strip of metallic
packing 9, pressed out by springs, applied at the point of contact,
whilst it revolves like a piston. There are two abutments or sliding
stops 10, 11, which are opposite to each other in the same diametrical
line, and which extending out through stuffing boxes 12 are connected
together by external cross heads 13 and rods 14, so as to work together
and so that as one is pushed out by the action of the eccentric boss 7
it causes the other one to move inwards, the inner ends, or rather
metallic packing strips 15 fitted thereto being always in contact with
the boss. The elliptical boss 7 is so fixed on the shaft 8 that the
centre of the latter is in a point of the shorter axis of the ellipse wherein
a straight line equal to the shorter axis, but placed at right angles
thereto, has its ends exactly (or very nearly so) in the circumference.
Such a point can be taken in any ellipse, but I prefer to take an
ellipse of about such proportions as that if the shorter axis is divided
into seven equal parts the point fulfilling the conditions will be at the
distance of two of those parts from one end. Then all straight lines
drawn through that point and having their ends in the elliptical cir-
cumference will be equal, or very nearly so, and the two sliding stops
will in consequence be kept at a practically uniform distance apart.
The packing strips 15 at the inner ends of the sliding stops 10, 11, arc
fitted into grooves in the latter, and in these grooves hemp is put
behind the packing strips, and behind the hemp, bars 16, which are
pressed inwards by rods indicated by dotted lines and extending through
to the outer ends of the sliding stops where they are acted upon by

page_text: springs 17, which can be adjusted with facility from the outside without
the necessity of opening any part of the engine. The packing strips 15,
are cylindrical, and what may be termed the theoretical ellipse for the
boss 7, should be drawn through their centres, the actual contour of
the boss being an inner ellipse, which cuts any normals of the theo.
retical ellipse at distances equal to the radius of the packing strips, that
is, in other words, an ellipse, the axis of which are each the same
distance (namely, that of the diameter of the packing strip) shorter than
those of the theoretical ellipse. The shaft 8 is made tubular, but with
a stop 18 at the middle of the engine, and the steam enters by one end
and passes off by the other, being led by two passages 19, 20, in the
elliptical boss 7 to suitable points on the circumference thereof, whilst
the exhaust steam passes off by two similar reversed passages indicated
by dotted lines at 21, 22. Two of the passages 19, 21, in the boss arc
by preference shaped spirally, so as to deliver the steam in a tangential
direction when it is issuing from either of them, the other passages
20, 22, may also be shaped spirally, but their office is simply to supple-
ment the action of the other passages when partly shut off by the
sliding stops 10, 11. The steam enters and leaves the shaft 8 by hollow
pedestals 23, 24, fitted with stuffing boxes where the shaft ends enter
them, and these pedestals communicate with passages in the bed
frame 6, and leading to ports in a valve chest 25, wherein a common
slide valve 26 is arranged for reversing the engine, the steam entering
by a pipe 27, and passing off by a pipe 28. Plates 29, turned to
accurately fit inside the cylindrical chamber 1, are used for packing the
ends thereof, and are adjusted by means of the stuffing boxes 30, which
are arranged to be screwed to the external end covers 3, 4. I also
prefer to apply packing rings 31, in the end faces of the elliptical boss 7,
to work upon the plates 29, such rings being bevilled on their outer
edges so as to be forced against the plates by the expanding spring set
that is given to them.
Instead of the chamber 1 being fixed, and the shaft 8 revolving the
shaft be fixed whilst the chamber revolves on it, or both parts
may
may be arranged to revolve in opposite directions or at different
velocities. Instead of admitting and exhausting the steam by passages
in the shaft and boss as described, passages and ports for that purpose
may be made in the cylinder 2, the inlet and outlet being controlled
by reciprocating valves or not according to arrangement.

page_text: The engine may obviously be driven by any other convenient fluid
under pressure instead of steam, such for example, as water passing
through it for the purpose of being measured, in which case ordinary
meter counting mechanism may be connected to the shaft to record
the number of revolutions. On the other hand the apparatus acts
as a pump on applying any convenient external power to turn the
shaft.
Having thus particularly described my said Invention, and the
manner in which the same is to be performed, I have to state that I
do not restrict myself to the precise details herein described or
delineated, and that I do not claim the arrangement of the inlet
and outlet passages and reversing valve, but that what I believe to
be novel and original and claim as the Invention secured to me by the
herein-before in part recited Letters Patent is, the combining of an
elliptical boss with connected sliding stops in a cylindrical chamber to
form rotatory motive power pumping and measuring apparatus, sub-
stantially as herein-before described.
In witness whereof, I, the said James Angelo McElroy have
hereunto set my hand and scal, this Sixth day of September, in
the year of our Lord One thousand eight hundred and sixty-nine.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JAMES A. MCELROY. (L.S.)