IMPROVEMENTS IN FLUID PUMPING MEASURING AND EXHAUSTING APPARATUS APPLICABLE ALSO TO MOTIVE PURPOSES.
Year: 1882

page_text: LETTERS PATENT to Benjamin Walter Davis, of Lambeth, in the County of
Surrey, Engineer for an Invention of IMPROVEMENTS IN FLUID PUMPING
MEASURING AND EXHAUSTING APPARATUS APPLICABLE ALSO TO MOTIVE
PURPOSES.
"
PROVISIONAL SPECIFICATION left by the said Benjamin Walter Davis at
the Office of the Commissioners of Patents on the 14th October 1882.
BENJAMIN WALTER DAVIS, of Lambeth, in the County of Surrey, Engineer,
"IMPROVEMENTS IN FLUID PUMPING MEASURING AND EXHAUSTING APPARATUS
APPLICABLE ALSO TO MOTIVE PURPOSES
"
My invention relates to machines known as annular or rotary pumps, applicable
to the pumping, exhaustion, or measuring of fluids, and is designed to increase the
capacity and to discharge constantly, evenly, and without shock, enabling the
pump to run easily at high velocities, and to reduce leakage to its lowest possible
extent.
My apparatus for effecting these results consists of a pair of drums or cylinders
rotating on parallel axles within a common case or framing, provided with an inlet
and outlet, placed on opposite sides of the casing, in a line between the two rotating
drums.
The proper and mutual rotation of the drums is ensured by gearing on their axes
outside the casing, one of the drums being driven by any external driving power by
any convenient means.
The essential novelty in the construction of the drums consists in projections of
special form on one or both, engaging and accurately fitting, as to the point of the
said projections, into recesses of special shape, provided so as to come in proper
juxta position with the projections as the drums revolve.
The flanks of the projections are set out by two epicycloidal curves meeting in a
point (which may be flattened to whatever extent may be found desirable) as
generated by the corners of the recess on the engaging drum

page_text: The form of the recess also is that of a curve, as generated by the point of the
projection engaging into it.
The construction thus carried out, of the respective projections and recesses,
ensures that the point of the projection is always in water-tight contact with the
interior surface of the recess, and also on the interior surface of the casing. When
the drums are driven in opposite directions by external driving power, the water-
tight contact, between the projections and recesses of the drums, produces an
exhaustion from or inflow to the inlet port, and a delivery outwards through the
opposite outlet port.
Conversely if a liquid be forced by pressure through the apparatus it will act
either as a meter of the flow, or a water engine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Benjamin Walter Davis in the Great Seal Patent Office on the
13th April 1883.
BENJAMIN WALTER DAVIS, of Lambeth, in the County of Surrey, Engineer,
"IMPROVEMENTS IN FLUID PUMPING MEASURING AND EXHAUSTING APPARATUS,
APPLICABLE ALSO TO MOTIVE PURPOSES
"
My invention relates to machines known as annular or rotary pumps, applicable
to the pumping, exhaustion, or measuring of fluids, and is designed to increase the
capacity, and to discharge constantly, evenly, and without shock, enabling the
pump to run easily at high velocities, and to reduce leakage to its lowest possible
extent.
My apparatus for effecting these results consists of a pair of drums or cylinders
rotating on parallel axles within a common case or framing, provided with an inlet
and outlet, placed on opposite sides of the casing, in a line between the two rotating
drums
The proper and mutual rotation of the drums is ensured by gearing on their axes
outside the casing, one of the drums being driven by any external driving power,
by any convenient means.
The essential novelty in the construction of the drums consists in projections of
special form on one.or both, engaging and accurately fitting as to the point of the
said projections, into recesses of special shape, provided so as to come in proper
juxta-position with the projections as the drums revolve.
The flanks of the projections are set out by two epicycloidal curves meeting in a
point (which may be fattened to whatever extent may be found desirable) as
generated by the corners of the recess on the engaging drum.
The form of the recess also is that of. a curve as generated by the point of the
projection engaging into it.
The construction thus carried out, of the respective projections and recesses,
ensures that the point of the projection is always in water-tight contact with the
interior surface of the recess, and also on the interior surface of the casing. When
the drums are driven in opposite directions by external driving power, the water
tight contact, between the projections and recesses of the drums, produces an
exhaustion from, or in-flow to, the inlet port, and a delivery outwards through
the opposite outlet port.
Conversely, if a liquid be forced by pressure through the apparatus, it will act
either as a meter of the flow, or a water engine.
And in order that my invention may be properly understood I now proceed to
describe the same with regard to the drawings hereto annexed.
Like letters refer to similar parts in the different Figures.
Figures 1 and show transverse and longitudinal sections respectively through
my_apparatus arranged as a pump or a motor.
Figures 3 and 4 show transverse and longitudinal sections respectively through
my apparatus arranged as a meter.
A A are a pair of drums or cylinders rotating with the parallel axes B B within
the case or framing O provided with an inlet D and an outlet E, or vice versa.
The drums are provided with two or more projections or teeth F F, which touch
the interior circumference of the external casing C with their points, and also the
interior faces of the end covers G G with their cheeks or sides, so as to make
water-tight contact all round.
The axes B B of the drums are carried in bearings g. g. in the end covers, and at
such a distance apart that the plain circumferences of the drums are just in contact,

page_text: and roll on one another when revolved. The said axes, where they pass through
the stuffing box H in one of the covers, are geared together outside the casing by
the wheels K, so that the drums necessarily revolve in opposite directions and
simultaneously to one another.
Recesses L L are therefore provided in the proper parts of the drums, which will i
admit the teeth or projections on the neighbouring drum as they revolve together.
The curves of the flanks of these projections on the drums and the interior curves
of these recesses are particularly set out in the following manner.
The flanks of the projections are set out by two epicycloidal curves ff meeting
in a point, (which may be flattened to whatever extent may be found desirable) as
generated by the corner of recess, which is a point on the circumference of one of
the drums rolling upon the other equal drum.
The interior curve of the recess L is generated by the point of the epicycloidal
tooth on the neighbouring drum. As the tooth and recess engage, there are always
three points simultaneously in contact:the point of the tooth with the surface of
'the recess, and each corner of the recess with the two flanks of the tooth.
.
When then the drums are driven in opposite directions by any convenient
external power, the water tight contact between the projecting teeth and the
recesses, and also between the sides of the drums and teeth and the covers, causes
an exhaustion from or inflow to the inlet port, and a consequent delivery outwards
through the opposite outlet port.
Conversely if a liquid be forced by pressure through the apparatus, the liquid
will cause the drums to rotate, and thus develope power as a motor. O₂, Figure 4,
the rotating shaft, may be connected up by suitable mechanical means to a
counter M, Figure 4, which will thus indicate the number of revolutions of the
drums, and consequently a measure of the liquid passed through the apparatus.
In the case of the meter I arrange the entry and exit ports NO tangentially
to the drums, and introduce baffle pieces P, to prevent any shock from the
inrushing water.
Having now described and ascertained the nature of my invention and the
manner of carrying the same into effect, be it known that what I consider novel
and desire to protect by Letters Patent is:-
In a Rotary pump, motor, or meter, the combination of two parallel geared
drums provided with two or more teeth or projections and recesses on the one,
engaging with water tight contact into corresponding recesses and projections on
the other, the curves of the said projections and recesses being particularly gene-
rated as herein described; with an external fitting case and covers provided with
inlet and outlet, substantially as and for the purposes describeḍ
In witness whereof I the said Benjamin Walter Davis have hereunto set
my hand and seal this twelfth day of April in the year of our Lord One
thousand eight hundred and eighty-three.
Witness.
S. P. WILDING.
23 Rood Lane, London, E.C.
Patent Agent.
BENJAMIN WALTER DAVIS (LS.)