An Improved Rotary Pump or Motor.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
An Improved Rotary Pump or Motor.
I, GEORGE SHANNON LUTTRELL of 70 St. John Street, Launceston in the Colony
of Tasmania, Student do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to provide a rotary pump of improved yet simple
construction and usable as a motor as is the case with other pumps of the same class.
The invention consists in the novel combinations of parts which are hereinafter
described, and which materially conduce to reduced friction in working, and tend to
economy in construction.
In describing a pump constructed in accordance with my invention it will suffice
to explain a form in which there are three vanes (the invention being adapted to the
use of more, but not of less than three).
The pump casing has ends or covers and has within it a pump chamber the
peripheral surface of which is formed of portions of two cylinders the larger portion
(on one centre) traversing 240 degrees as nearly as conveniently practicable and
the smaller portion (on a different centre) traversing the distance between the
ends of the first named portion. The inlet and outlet respectively are so placed
that the former meets one end of the above cylindrical portions, and the latter.
meets the other end thereof. In practice it is found convenient to bore out a
complete cylinder, and then to fit in a block having the smaller cylindrical surface
above described.
On the same axis as the said shorter cylindrical portion is a central shaft
through a rotary drum which has therein equidistant radial grooves, there being also
a recess at each end of the drum which leaves an annular rim at each said end, each
rim fitting closely against its own end of the chamber. In practice a suitable way
of constructing the drum is to take a three flanged shaft and to cast the rest of
the drum thereupon. The drum contacts with the larger cylindrical surface
midway of the length of the latter. The vanes have their inner portions adapted
to fit into and slide forward and back in the grooves, one vane in each groove,
as to fit the same
each vane extending from end to end: of the chamber so
closely. Each vane is provided with a lug or narrower part so as to form a recess
at each end, parts of said recesses being occupied when the parts are fitted together
by cam plates one of which projects inwardly from each cover or end of the chamber.
The cams are inade in one piece with the ends, or otherwise. An aperture through
each cam continued through the covers allows the shaft to pass through, the shaft
having suitable bearings and stuffing boxes and any other usual connections to enable
power to be communicated to the shaft, or derived from the same. The peripheral
surface of each cam is bounded by portions of two cylinders the larger portion
traversing nearly 240 degrees; and the smaller portion joining the ends of the
larger and being concentric with the aforesaid smaller cylindrical portion of the
chamber itself. The curved angles where these two surfaces of the cam meet are in
Each vane at
practice rounded off to allow the vanes to pass easily round the same.

page_text: each end extends radially from the surface of the chamber to the surface of the cam
(fitting as exactly as practicable at some parts and a little loosely at others where
exact fitting is not material).
In operating a pump constructed as thus indicated the rotation of the shaft and
drum drives the vanes around in the limited space between the cam and the
peripheral surfaces of the chamber. At one point in the circuit each vane will lie
entirely within its groove whilst as the rotation proceeds the cam surface forces the
vane outward until at the beginning of the smaller cylindrical portion of the chamber
it is at its furthest distance from the centre. During that portion of the stroke in
which the vane traverses said smaller cylindrical portion the distance of the vane
from the centre remains constant after which the other cylindrical surface of the
chamber causes the vane to pass further and further into its groove until the cycle
is complete. The number of equidistant vanes may be increased without departing
from the essential features of this invention. For example the length of the larger
cylindrical part of the chamber may be as nearly practicable 288 degrees, and the
other cylindrical part correspondingly smaller when there are five equidistant vanes,
so that the smaller part will stiil extend at least the full distance between two vanes,
and from inlet to outlet, as in the case of a three vane pump.
1
1°
1005
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.
1, GEORGE SHANNON LUTTRELL, of 70 St Johns Street, Launceston, in the Colony
or Tasmania, Student, 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 :-
The object of this invention is to provide a rotary pump of improved yet simple
construction and usable as a motor as it is the case with other pumps of the same
class. The invention consists in the novel combination of parts which are hereinafter
described, and which materially reduce friction in working, and tend to economy in
construction.
The drawings attached illustrate a pump constructed in accordance with my inven-
tion, in which there are four vanes (the invention being adapted to the use of more,
but not of less than three) and in these, figure 1 represents a sectional elevation on
the line X X in figure 2: and figure 2 represents a sectional elevation on the line Y Y
in figure 1: figure 3 represents the rotary drum having equidistant grooves therein :
figure 4 shows the inside of one of the covers or end pieces of the pump chamber
showing bolt holes, cam and shaft aperture: figures 5 and 6 represent respectively a
side and an end elevation of one of the vanes: figure 7 is a diagram of centres, curves
and radii.
A shows the casing having ends or covers A¹ and having therein the pump
chamber B the peripheral surface of the chamber being formed of portions of at
least two cylinders. I find four the most suitable number although the difference in
position compared with two cylinders is exceedingly slight and does not affect the
substance of the invention.
One portion shown by the are C in figures 1 and 7 is on a centre C¹ and with the
parts D and E¹ traverses 240 degrees as nearly as conveniently practicable: these parts
extend to the projecting radial lines in figure 7 and the other peripheral portion shown
by the arc D is on a centre D¹ and traverses about 120 degrees. The middle part D¹¹
is short and is also on centre D¹. E and F are the pump inlet and outlet respectively

page_text: the foriner meeting one end and the latter meeting the other end of D.
In practice
it may be more convenient to bore out a cylinder from one centre and then to fit in,
a block or blocks eaving surfaces true to the other centres.
The centre D¹ is the axis of G which is a central shaft through the rotary drum H,
the equidistant radial grooves in which are shown by I, there being a recess J at each
end of the drum which leaves only an annular rim K at each end, the rim fitting
closely against the end A¹ of the chamber. The drum H contacts with the surface D¹i.
L are vanes having their inner portions adapted to fit into and slide forward and back
in the grooves I. One vane slides in each groove, each vane extending from end to
end of the chamber so as to fit the same closely. Each vane may be provided with a
centrally projecting lug or narrower part, (not shown in drawing) so as to leave a
recess at each end of the vane, parts of said recesses being occupied when the parts
are fitted together by can plates M, one of which projects inwardly from each end A¹.
But as it does not alter the material parts of the invention, I prefer to use thick
annular parts K whereby such lugs become unnecessary. The cams are made in one
piece with the. ends or otherwise. An aperture M¹ (figure 4) through each cam,
continued through covers A', allows the shaft G to pass through, the shaft having
suitable bearings and stuffing boxes P, and any other usual connections to enable
power to be communicated to the shaft, or derived from the same. The peripheral
surface of each cam is bounded by portions of two cylinders one portion shown by the
arc N (figures 7 and 4) traversing nearly 240 degrees on a centre N¹ the other portion,
shown by the arc O, joining the ends of N and being concentric with the arc D.
The curved angles where surfaces N and O meet are in practice rounded off to allow
the vanes to pass easily round the same. Each vane L at each end L2 extends radially
from the surface D to the surface O when traversing the curve D, and when between
the surfaces N and C, D, and E¹ it also extends from one towards the other (fitting
as exactly as practicable at Du but a little loosely at C and E').
In operating a pump constructed as thus indicated the rotation of the shaft and
drum drives the vanes around the limited space between the cam and the peripheral
surfaces of chamber B. At D each vane L lies entirely within the groove I, whilst
as the rotation proceeds in the direction shown by the arrow R (fig. 1) the cam
surface N forces the vane outward until at the beginning of curve D it is at its
furthest distance from the centre D¹. During that portion of the stroke in which
the vane moves in contact with curve D the distance of the vane from the centre
remains constant after which the surface C causes the vane to pass further and further
into its groove until the cycle is complete.
It will be obvious that the surface N need not be part of a cylinder, and a cam edge
which would give room for the vane could be made by setting out and working to a
sufficient number of such points as would be touched by the inner edge of 1.2 whilst
the outer edge of the vane moves round in contact with surfaces C, D, and E¹.
In practice, I find it more economical and satisfactory to make the surface N
cylindrical, and I do it by setting off three points (two from the ends of curve D and
one from the centre of curve D₁) each point being locked the length of L2 radially
inward and I find the centre of a circle which would pass through those points: that
centre is N¹ (figure 7). The number of equidistant vanes may be increased without
departing from the essential features of this invention and sundry alterations of mere
detail may likewise be made whilst retaining subject matter herein below claimed.
For example the combined length of the part C, D, and E¹ may be as nearly
practicable 288 degrees and the part D correspondingly shorter when there are five
equidistant vanes so that D will still extend at least the full distance between two
vanes.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1 The rotary numn abomber R formand hun soring howing the
11

page_text: 2. In combination with a rotary pump chamber an end piece or cover having the
cam M provided with the cylindrical surfaces N and O as set forth.
3. The combination and arrangement with a rotary pump chamber having
cylindrical surfaces as set forth in claim 1 of a drum having grooves, and vanes
adapted to slide therein substantially set forth.
4. The combination and arrangement with a rotary pump chamber having the
cylindrical surfaces as set forth in claim 1 of a drum having grooves and vanes and
of cams having the surface O, substantially as set forth.
5. The combination as a whole of the parts herein before described constituting a
rotary pump substantially as illustrated.
1807
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.