This invention is a fluid flow meter with pulse output proportional
to the fluid flow rate. The pulse is tranduced by means of a pick-off
sensor from the by-passing of a ball which travels in a toroidal
passageway at speed close to that of the velocity of the fluid.
The fluid flowing into the device follows a loop-shaped circular
passageway while the ball travels in a closed circular passageway.
Fluid flow propels the ball to revolve continually at a rate directly
proportional to the flow rate of the fluid.
1. A fluid flow transducer comprising
two housing halves of impervious material both having a groove
of circular shape and of semicircular cross-section, said grooves
forming a toroidal passageway for fluid in said housing when combined,
one orifice in each said housing half at the bottom of said groove,
said orifices being, when said housing halves combined, located
on opposite sides of said passageway and being off-set from the
exact opposite location by one full revolution of said combined
housing halves less one distance of the orifice diameter, one connection
means for fluid on the outside of each said housing half connected
to said corresponding orifice in parallel direction that is less
than 45 degrees but more than 5 degrees to the plane defined by
the center line of said toroidal passageway, characterized in that
the cross-sectional areas of said toroidal passageway, said orifices
and said connection means are equal or nearly equal,
a ball slightly smaller than the inner diameter of said passageway,
fastening means to form a fluidtight enclosure of said two housing
halves, whereby the motion of said ball indicates the velocity of
2. A fluid flow meter according to claim 1 wherein
a pick-off means is positioned close to said passageway.
3. A fluid flow meter according to claim 2 wherein
a signal processor is connected to said pick-off means.
BACKGROUND OF THE INVENTION
Hitherto, the many fluid flow metering requirements have resulted
in numerous different types of flow meters. The operational principles
of flow meters vary a lot; listed here are a few classes: differential
pressure flow meters, mass flow meters, area flow meters, electromagnetic
flow meters, positive displacement flow meters, and open channel
flow meters. All of these have specific areas of application but
have also their limitations, as for example: some do not operate
in reverse flow conditions; some must be mounted only in one position;
some do not work well with soily or opaque liquids; some require
individual calibration; some are not easily convertible to digital
display output nor remote display; some must have see-through tubes;
and some may become damaged by pressure variations or by changes
in physical state of the fluid being measured.
One aspect appears to be common to a great many flow meters: the
price--they are quite expensive. In many cases this is the result
of the intricate nature of the device and the resultant high degree
of accuracy required in manufacturing the component parts. In other
cases individual calibration is a necessary requirement leading
to the high price.
The idea in the present invention is to have as a moving part a
ball and as a housing material having groves and holes, through
which fluid may flow unobstructively, thus causing the ball to follow
the total volumetric velocity of the fluid without leaving the housing
body. This permits the revolutions to be counted, and from this
volume, flow rate and other data can be computed, indicated, recorded
It is an object of the present invention to accomplish accurate
measurement of fluid flow in a way that allows inexpensive fabrication
of the device through mass production.
Other objects of this invention are to make the device: respond
well to changes in flow over a wide range of flow rates, especially
in the laminar region; to handle pure fluids as well as true solutions,
colloidial dispersions and suspensions of fluids; handle high viscosity
liquid and non-Newtonian fluids; unsusciptible to changes in viscosity
or temperature of the liquid; offer little resistance to fluid flow;
unaffected from hammer effect; and capable of measuring pulsating
Further objects of this invention are to provide a device which
is simple in design, construction and operation; offers ease of
installation and maintenance; and has long service life.
In this invention the ball in the housing will follow the fluid
flow at a velocity very close to the velocity of the fluid. This
invention may be classed as a positive displacement flow meter and
an area-velocity integrating type flow meter as it has the characteristics
of both. Making reference here to other similar looking devices
having a spinning ball and two orifices on the outer surface of
the toroid, and used as flow indicators, the basic difference to
these is in the arrangement of the orifices, explained later, which
makes these flow indicator devices perform differently and not part
of the positive displacement flow meter category.
For the fluid there are one inlet and one outlet orifice located
so that when the fluid entering at the inlet orifice has made almost
one full round within its circular passageway, it will exit at the
outlet orifice located almost opposite the inlet orifice. The ball
will otherwise follow the mass of the fluid but, due to the shape
and size of the outlet orifice, will not exit but travels past the
boundary line between the incoming and outgoing fluids, only to
start another cycle in the device. The pushing force of the fluid
is continuous, without interruptions, between the inlet and outlet
The toroidal passageway in the housing is as round and circular
in shape with as smooth a surface as can be manufactured without
extra effort. The ball is only slightly smaller than its passageway
to allow free travel, touching the wall of the passageway only at
one point, as a rule, or occasionally, at two points on locations
where an orifice is located, or at no point at all.
The inlet and outlet orifices in the passageway carry through the
housing to the outside surface where connections to pipe, hose,
tube or other fluid carrying enclosure or fitting can be made. A
good direction to the holes thus formed is close to the line which
is 17 degrees away from the direction of the tangent to the center
line of the toroidal passageway, the 17 degree-line being on the
perpendicular plane to the plane defined by the toroid's centre
line and the tangent to the centre line. The above direction minimizes
friction and turbulence; however, deviations from said direction
up to 45 degrees to the plane defined by the centre line do not
make the device inoperative. The two orifices, formed where the
holes from the exterior connection means meet the toroidal passageway,
are on the opposite sides on the passageway but slightly off, allowing
the fluid to flow easily into and out of the passageway.
The most prevelent application of this invention is envisioned
as that of measuring flow rates of liquids in situations where digital
read-out is required, or, where signals, directly proportional in
frequency to the flow rate, carry the information to the processor.
To the large family of different types of flow meters this invention
is a newcomer, suitable for many uses. For example, this invention
can be used when an inexpensive device with electronic pulse output,
together with a signal processor, is required, e.g. in aircraft
for measurement of gasoline consumption. In automobiles and boats
and ships this invention can provide similar invention.
In any watercraft this invention, when installed to read water
speed, can measure the speed of the vessel, the distance travelled,
In industrial applications the flow rate of many types of liquids
can be measured because the invention can be made of metals or plastics.
Monitoring, batching and totalizing of volumes of liquids as part
of process control is just a matter of selecting the appropriate
From the foregoing it should be apparent that the application of
the present invention overcomes numerous objections heretofore encumbering
the measuring of fluid flow, one important feature being the freedom
of mounting in any position.
In the following explanatory description of this invention reference
is made to the accompanying drawings, to wit:
FIG. 1 is an isometric view, half-way transparent, of the fluid
flow metering device.
FIG. 2 is a sectional view of the fluid flow metering device taken
in the plane indicated by line II--II of FIG. 3 and showing the
location of the toroidal orifices in relation to each other and
to the external connection means. This view also shows the male-type
external connection means and the clamp-type fastening means of
the housing halves.
FIG. 3 is a sectional view of the fluid flow metering device taken
in the plane indicated by line III--III of FIG. 2 and showing the
ideal location of the inlet orifice in relation to the external
connection means and to the toroidal passageway. This view also
shows the male-type input connection means and the screw-nut type
fastening means of the housing halves. The sectional view taken
in the opposite direction of the plane III--III is identical to
It is considered that the most advantageous application of the
idea embodied in this invention is to be found in a fluid flow metering
device constructed as follows:
The passageway 1 shaped as a toroid, is formed by two housing
halves 2a and 2b, each having a grove of semicircular section, when
the housing halves 2a and 2b are fastened together. The housing
halves 2a and 2b also contain the orifices 3 and 4 leading, within
the housing halves 2a and 2b, to the inlet and outlet connection
means, male 5a and 6a, or female 5b and 6b.
In operation the flow of fluid through the device can be in either
direction, and the use in this specification of terms `inlet` and
`outlet` is only for clarity of description. Also, the connecting
means may be male, female, or other as per need.
The ball 7 enclosed within the passageway 1 is the only moving
component. The diameter of the ball 7 is slightly less than the
diameter of the passageway 1.
The inlet orifice 3 and the outlet orifice 4 in the passageway
1 are sized, shaped and located is such a manner that the fluid
flowing through the passageway 1 will move with little friction
and will direct its force in the direction of its travel.
The size of the orifices 3 and 4 is close to the cross-sectional
area of the inlet and outlet connection means 5a or 5b and 6a and
6b as well as to the passageway 1. This reduces the minor losses
due to acceleration and deceleration of the fluid, and thus the
overall pressure drop across the fluid flow meter, to the minimum.
The shape of the orifices 3 and 4 is, preferably, close to that
of a droplet. When fluid enters the passageway 1 at an angle less
than 45 degrees this shape directs the centre of mass of the fluid
towards the centre line of the passageway 1.
The location of the orifices 3 and 4 when viewed in the direction
of line 1 is such that the droplet heads are touching but not overlapping
each other, and the two holes connecting the orifices 3 and 4 with
the inlet and outlet connection means 5a or 5b and 6a and 6b are
off by one hole width as shown in FIG. 2. At the location between
the orifices 3 and 4 on the line 1 the incoming fluid meets and
directs out the fluid just as it is about to complete a revolution
in the passageway 1. Thus all fluid enters the passageway 1 without
shortcutting to the opposite outlet orifice 4 and, consecuently,
the ball has the least distance to clear without propulsion before
starting a new round.
The means of fastening the housing halves 2a and 2b are: 8a is
a typical rivet, screw, screw-nut combination, or similar; 8b is
a clamp outside the housing 2; and 8c is a permanent bond. Fastening
means 8a and 8b require the gland 9 and seal 10 outside the passageway
1 to make a fluidtight joint.
The pick-off means 11 is located perpendicular to the passageway
1 and may operate on the optoelectronic principle, if the housing
halves 2a or 2b, or both or part of them are transparent; or, may
operate on the proximity sensing principle, e.g. inductive, capacitive,
or magnetic, if the housing halves 2a and 2b are opaque.
The signal processor 12 is equipped with proper readout display
and is connected to the pick-off means 11.
All materials embracing the fluid are impervious and joined to
form a fluidtight enclosure. Either thermoplastics or thermosetting
plastics can be utilized for this purpose, as can other materials,
such as metals and glass. Selecting appropriate materials for the
housing halves 2a and 2b and the ball 7 involves taking into consideration
the effect the fluid will have on the materials and the requirements
of the pick-off means, and the workability of the materials. Selecting
proper material for the ball 7 also involves choosing a material
with low specific gravity, or if a material with high specific gravity
is chosen, e.g. a ferromagnetic plastic, then the ball 7 would have
to be hollow to reduce its weight.
I have discovered that device, being otherwise similar but having
holes at different angles, i.e. angles formed by the line 1 and
the plane on the centre line of the toroid, perform differently.
Other factors being same, devices having different size passageways,
also perform slightly differently. In theory, viscosity of the fluid
being measured has the dominating effect on the above performance;
however, in practice, with proper dimensioning, the effect of viscosity
on this invention is less than on most other types of flow meters.