Improvements in Fluid Pumps, Meters, and Motors.
Year: 1891

page_text: Date of Application, 17th Jan., 1891
Complete Specification Left, 16th Oct., 1891-Accepted, 21st Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Fluid Pumps, Meters, and Motors.
I, JAMES ATKINSON, of 3 Nassington Road, Hampstead, London, N.W.
Engineer do hereby declare the nature of this invention to be as follows:-
This invention has for its object the improvement of rotary apparatus for forcing
or exhausting air or other gases, and in some instances liquids; it may also be used
as a motor, or a meter.
I employ two parallel shafts geared together by means of an equal pair of spur
wheels, or, (as will be subsequently explained), so connected that they revolve
uniformly in opposite directions; these parallel shafts pass through a suitable
casing which in section has the outer sides consisting of parts of circles struck
from the centres of the shafts, joined by (say) straight lines top and bottom; the
"Root's
shafts and casing being similar to those used in what is known as a
Blower," or in rotary pumps commonly used consisting of a pair of geared wheels
working in such a casing. On each of the shafts a drum is fixed, the length of the
casing, each of these drums has attached to it, or cast in it, a number of blades
placed more or less radially, also of the length of the casing and extending outwards
so as to touch (or almost touch) the cylindrical parts of the casing. The number
of blades may vary very considerably, but six in each drum would be a suitable
number for many purposes. The drums are so arranged with respect to each other
that in revolving the blades of one drum pass midway between those of the other
drum; and the shafts are so placed with respect to each other that the points of
the blades enter into curved recesses in the drums provided for them midway
between the roots of the blades.
The blades consist of some suitable material, such as wrought-iron, steel, or
bronze, purposely made somewhat elastic, the desired amount of elasticity being
obtained from making them of a suitable thickness, curving then, inclining them,
or in the mode of attachment, so that they will give way to any inaccuracy of
workmanship or of the gearing; and if unduly tight at any part, will gradually
wear themselves free; the points or ends of the blades bear against the circular
parts of the casing, and the corners of the ends of the blades (more or less rounded)
against the curved recesses.
Suitable inlet and outlet passages are arranged for the passage of the fluid.
Instead of gearing being used for the purpose of keeping the drums in the
proper positions with relation to each other, for some purposes, more particularly
with large machines, I employ two pairs of connecting rods connected at their
larger ends to crank pins fixed on each end of each shaft at right angles, the
connecting rods being in pairs at each end of the machine, the smaller ends of
each pair being connected to one crosshead, and the crossheads being guided in
straight lines at right angles to a plane passing through the shafts, the accurate
angular position of the shafts, drums, and blades to each other is maintained
without requiring gearing for this purpose. When driven directly by steam
engines, the connecting rods, crossheads and guides may form parts of such
engines; if a single engine is used, those at one end only of the machine forming
part of such engine; if two (which may be compounded) then those at both ends
being so used.
As with this class of machine there is always a certain unavoidable amount of
leakage, it is desirable to run them at a high speed, so that the leakage will bear

page_text: a smaller proportion to the amount of fluid delivered; the machines commonly in
use at present, when run at high speeds make a considerable amount of noise, due
mainly to the heavy rigid parts coming in contact with each other and also from
the gearing. In my invention rigid parts never come in contact with each other,
and gearing is not necessary, so that they can be worked satisfactorily at high
speeds, thus reducing leakage and enabling a machine to do more work.
When six blades are used in each drum and the cylindrical parts of the casing
consist of semi-cylinders, three of these blades would always be in contact with the
casing and thus leakage in this direction materially reduced.
The flat ends of the drums have a number of shallow holes drilled in them at.
short distances from each other, these tend to reduce leakage, and friction, also
form chambers where dirt can accumulate, and where it is out of the way of the
rubbing surfaces.
Dated 17th J
1001
COMPLETE SPECIFICATION.
Improvements in Fluid Pumps, Meters, and Motors.
I, JAMES ATKINSON, of 3 Nassington Road, Hampstead, London, N.W. 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 has for its object the improvement of rotary apparatus for forcing
or exhausting air or other gases and in some instances liquids; it may also be used
as a motor or a meter.
For the purpose
of more fully explaining the improved apparatus I append three
sheets of drawings.
Sheet 1. shows a machine suitable for driving by belts in the manner in which
such machines are commonly driven, Fig. 1. being a section, Fig. 2. a plan on a
smaller scale and Fig. 3 an end view.
Sheets 2. and 3. show a machine as arranged to be driven directly by means
of a steam engine, Fig. 4. being a side elevation and Fig. 5. being an end
elevation.
I employ two parallel shafts A. and B. geared together by means of equal pairs
of spur gearing C. C₁ on one outer end of the shaft B. I fix a belt pulley D. and
on the opposite end of the shaft A. a similar pulley D₁. These pullies may be
driven by belts from any convenient driving shaft on which two equal sized pullies
are fixed, one of the belts being an open belt, and the other crossed, this being the
ordinary manner in which such macbines are driven, the shafts revolving uniformly
in opposite directions. The shafts A. and B. pass through a suitable casing E.
which in section has the outer sides consisting of parts of circles struck from the
centers of the shafts joined by (say) straight lines top and bottom, the shafts
and casing being similar to those used in what is commonly known as a
66 Root's
Blower."
i
On the shaft A. a drum F. is fixed and on the shaft B. a similar drum G. They
are made the same length as the casing so as to fit against the flat ends; the
drums F. and G. have attached to them or cast in them a number of blades H.,
placed more or less radially, and also of the length of the casing, these blades
extend outwards so as to touch or almost touch the cylindrical parts of the casing.
The number of these blades H. may vary, but four or six in each drum would be a
convenient number. The drums F. and G. are so arranged with respect to each
other that in revolving the blades of one drum pass midway between those of the
other drum, and the shafts A. and B. are so placed with respect to each other that

page_text: the points of the blades H. enter into curved recesses in the drums F. and G.
provided for them midway between the roots of the blades.
The blades H. are made from some suitable material such as wrought-iron, steel,
or bronze; they are made elastic, the desired amount of elasticity being obtained
by making them out of a suitable thickness of sheet metal (preferably); they also
may be curved or inclined, or so attached to the drums F. and G. that they will
give way to any inaccuracy of workmanship, or of the gearing, and if unduly tight
at any part will gradually wear themselves free; the points of the blades H. bear
against the cylindrical parts of the casing E. and the corners of their outer ends
(inore or less rounded) against the curved recesses.
"
A suitable inlet passage 1. and outlet passage J. are arranged for the passage of
the fluid which will take the course indicated by the arrows when the machine is
driven in the direction shown.
Instead of the spur gearing C. and C, being used for the purpose of keeping the
drums F. and G. in the proper angular position with relation to each other, in some
instances, more particularly with large machines I employ an improved method of
connecting the two shafts A. and B. to each other, this improved method being
also applicable to other types of machines of this description. This arrangement
is shown in Fig. 4. Sheet 2. and Fig. 5. Sheet 3. On each end of the shafts A.
and B. I attach a crank pin; the crank pins L. and M. being at one end are
shown in their lowest position; the crank pins N. and O. at the other end are
placed (say) at right angles to L. and M.; the crank pins L. and M. are attached
by means of connecting rods P. and Q. to one crosshead T. which is guided at
right angles to a plane passing through the center lines of the shafts A. and B.
and the crank pins N. and O are connected by the connecting rods R. and S. to
another crosshead U. similarly guided. When driven directly by steam engines
the connecting rods, crossheads and guides, may form parts of such engines; two
cylinders may be used as simple engines or as compounded engines, or one set of
connecting rods, crosshead and guide, may be used in connection with one cylinder
as shown in Fig. 4. Sheet 2. and Fig. 5. Sheet 3. in which V is the steam cylinder.
The machine as thus arranged with crank pins, rods and guides, instead of gearing
may also be driven by a belt or belts.
As with this class of machine there is always a certain unavoidable amount of
leakage it is desirable to run them at a high speed, so that the leakage will bear
a smaller proportion to the amount of fluid delivered; those commonly in use at
present especially when running at high speeds make a considerable amount of
noise, due mainly to the heavy rigid parts coming in contact with each other or
the casing and also from the gearing. In my invention rigid parts never come
into contact with each other, also gearing is not necessary, so that they can be
driven satisfactorily at much higher speeds, thus reducing leakage and enabling a
machine to do more work.
When six blades are used in each drum and the cylindrical parts of the casing
consist of semi-cylinders, as shown in the drawings, at least three of these blades
are always in contact with the casing, so that leakage in this direction should be
materially reduced.
The blades H. may be made in such a manner that they could be renewed or
adjusted at any time.
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 use of the elastic blades H. in conjunction with the drums F. and G., as
described and illustrated in Fig. 1. Sheet 1. of the accompanying drawings.
2. In rotary pumps, motors and meters, of the type described in the accom-
panying Specification, having a pair of parallel shafts revolving in opposite
directions, the maintenance of the proper relative angular positions of these

page_text: shafts, by means of crank pins at (say) right-angles, double connecting rods, and
guides, instead of gearing, as described and illustrated in Fig. 4 Sheet 2. and
Fig. 5. Sheet 3. of the accompanying drawings.
3. The general arrangement and construction of rotary pumps, motors and
meters as described and illustrated.
Dated this 15th dox of October 1901.
JAMES ATKINSON.