Abstrict A turbine for a multijet fluid flow meter having a planar disk
mounted for rotation in the meter housing includes a plurality of
vertical blades supported normal to, and by, the disk. A ribbed
shaft carried by the disk drives a counter. The disk may include
braking ribs on the upper or lower surface for slowing rotation
of the disk when subjected to strong fluid flows. Various blade
configurations are contemplated, and the turbine may additionally
take the form of a duality of parallel disks interconnected by a
plurality of blades normal to both disks.
Claims What is claimed is:
1. A turbine for a multi-jet liquid meter of the type including
a counter and a housing having a first array of openings in a lower
wall portion and a second array of openings in an upper wall portion,
the first array facilitating influx of liquid into the housing and
the second array facilitating outflux of said liquid from said housing
so that a flow of said liquid is generated in said housing, said
turbine comprising:
a thin horizontally disposed disk having a peripheral region and
a central region, and wherein said disk includes means for slowing
its speed of rotation during strong liquid flows;
shaft means for rotatably supporting said plate means in said housing;
and a plurality of blades supported perpendicular to, and only
in the peripheral region of, said disk, for propelling said plate
means in rotation in response to said liquid flow in said housing,
said blades extending radially of said plate means;
said shaft means including means for interconnecting said disk
central region with said counter.
2. The turbine of claim 1 wherein said slowing means consist of
perforations in said disk located between two adjacent blades.
3. The turbine of claim 1 wherein said slowing means consist of
ribs disposed on the upper face of said disk and positioned above
each of said blades.
4. The turbine of claim 1 wherein said slowing means consists
of ribs disposed on the lower face of said disk and extending radially
between each of said blades and said disk guide means.
5. A turbine for a multi-jet liquid meter of the type including
a counter and a housing having a first array of openings in a lower
wall portion and a second array of openings in an upper wall portion,
the first array facilitating influx of liquid into the housing and
the second array facilitating outflux of said liquid from said housing
so that a flow of said liquid is generated in said housing, said
turbine comprising:
plate means;
shaft means for rotatably supporting said plate means in said housing;
and
a plurality of blades supported by, and perpendicular to, said
plate means, for propelling said plate means in rotation in response
to said liquid flow in said housing,
said blades extending radially of said plate means,
said shaft means including means for interconnecting said plate
means with said counter, and
said plate means including means for slowing its speed of rotation
during strong liquid flows.
6. The turbine of claim 5 wherein said slowing means consist of
perforations in said plate means located between adjacent blades.
7. The turbine of claim 5 wherein said slowing means consist of
ribs disposed on the upper surface of said plate means and positioned
above each of said blades.
8. The turbine of claim 5 wherein said slowing means consist of
ribs disposed on the lower surface of said plate means and extending
radially between each of said blades and a central portion of said
plate means.
Description BACKGROUND OF THE INVENTION
This invention relates to the field of devices intended to measure
the delivery and/or the rate of flow of a liquid. In particular,
it relates to a new multi-jet turbine adapted to be used with a
meter for liquids, such as water.
Water meters known as "first connection" meters for example,
those installed at the base of a building, can be classified in
two main groups: volumetric meters which typically employ a piston,
oscillating disk or revolving cylinder type; and rotary speed meters
in which water passing through the meter causes rotation of an enclosed
rotary device and the column of the passing water is measured from
the number of revolutions made by the rotary device. The latter
can be of either the single jet type, as for example a millwheel
in the water, or of the multi-jet type in which a turbine or rotor
disposed in a cylindrical distributor pierced with two superposed
rows of inlet or outlet holes, is rotatable driven so that its rotation
causes movement of a revolving needle or numbered roller counter
for measuring the delivered fluid.
More specifically, the invention is a multi-jet device of this
type and comprises an improvement in the system of the turbine.
SUMMARY AND OBJECTS OF THE INVENTION
One of the main objects of the invention is therefore to eliminate
the drawbacks of the conventional turbine and to provide distributor
systems that enables hydraulic division and equilibrium of the fluid
without disturbance so as practically to attain ideal circulation
and metering conditions of the fluid.
Another object is to provide a rotor with a lightened structure,
immediately adaptable to distributor housings of said type having
a design making it possible to achieve fluid meters, particularly
water meters, with great reliability.
According to the invention, the new turbine is essentially characterized
by a series of vertical blades, oriented concentrically to the shaft
of the turbine which are all connected by their upper end to a thin
horizontal disk having a central perforated part functioning as
a guide for a ribbed or splined rod for connection to the counter,
known in the art, of the meter.
Thus, in this new rotor design adapted to a standard distributor
housing, the turbine central part that disturbs the hydraulic equilibrium
is totally eliminated, the zone of centrally located swirling fluid,
present in conventional distributors, is no longer isolated from
the spiral of circulation of flow, and mixing of liquid currents
is performed homogeneously, without disordered turbulence or tumultuous
interaction of the jets of flow.
Moreover, the turbine of the present invention exhibits other advantages.
For example, the presence of the disk connecting the blades, which
offers a large surface for the action of the drive flow, appreciably
facilitates the rise of the turbine under the action of forces which
impart motion to the turbine. The disk, which produces a centrifugal
force, exhibits the advantages of protecting the element or rod
connecting the counting system of the meter. These elements previously
have exhibited frequent clogging for example, by magnetic particles
with counters of the magnet type, or by premature wearing via sandy
grains with rods of the gear type.
Of course, because the turbine of the present invention does not
change the hydraulic structure of the flow, it is possible to realize
all of its advantages by changing in various ways the shape of the
blades to benefit as much as possible from all the types of movements
of the liquid.
BRIEF DESCRIPTION OF THE INVENTION
To better understand the development of the inventive idea and
the advantage of the improvements made, a detailed description of
the invention will follow with reference to the various figures
of the drawings, in which:
FIG. 1 is a perspective view of a conventional distributor and
its turbine;
FIG. 2 is a top view of the bottom section of the distributor with
a representation of the orientations of the input liquid flow;
FIG. 3 depicts the flow pattern of a liquid jet within the distributor
during rotation of the turbine;
FIG. 4 is a partially sectioned view of the distributor illustrating
the flow within various parts;
FIG. 5 is a top view of a conventional turbine;
FIG. 6 is a perspective view of a turbine according to the present
invention;
FIG. 7a illustrates a first variation on the configuration of the
turbine blade shown in FIG. 6;
FIG. 7b illustrates a second variation of the turbine blade configuration;
FIG. 7c illustrates a third variation of the turbine blade configuration;
FIG. 7d illustrates a fourth variation of the turbine blade configuration;
FIG. 7e illustrates a fifth variation of the turbine blade configuration;
FIG. 8 is a side elevational view of one embodiment of the turbine
of FIG. 6 including a connecting rod mounted thereon;
FIG. 9 is a side elevational view of a second embodiment of the
turbine of FIG. 6 illustrating an alternative location of the bearing
collar for a connecting rod;
FIG. 10a is a side elevational view of one embodiment the turbine
of present invention having an integrally mounted connecting rod;
FIG. 10b is a side elevational view of an alternative embodiment
of the turbine of FIG. 10a;
FIG. 11 is a graph illustrating characteristics of fluid flow in
various multi-jet flow meters;
FIG. 12 is a perspective view of a variant turbine according to
the present invention;
FIG. 13 is a perspective view of another variant turbine according
to the present invention; and
FIG. 14 is a side elevational view of yet another variant turbine
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIGS. 1-5 of the drawings, there is shown a conventional
multi-jet liquid flow meter including a hollow cylindrical distributor
1 provided with circumferentially disposed, substantially tangentially
directed holes or openings. These openings are arranged in the lower
portion of the housing side wall in a first array and in the upper
portion of the side wall in a second array, and the openings 2 of
the first array are directed tangentially inwardly from the distributor
outer surface to produce an input fluid flow, while the openings
5 are directed tangentially outwardly from the distributor inner
surface to produce an output fluid flow. The first array of openings
2 facilitates introduction or induction of a fluid into housing
1 in a circulatory pattern as shown by arrows 3 and the second
array of openings 5 facilitates evacuation or expulsion of the fluid
from the housing (to the outlet opening of the meter) in a circulatory
pattern as shown by arrows 6. A turbine 7 is mounted within the
housing interior on a centrally disposed lug 8 the latter being
engaged in a hollow shaft 9 of the turbine. An upwardly projecting
ribbed or splined rod 10 is carried by the turbine for connection
to the counter of the meter guage.
The flow 3 of input fluid, which rotatively drives turbine 7 follows
a spiral course (see FIG. 3) from inlet openings 2' to outlet openings
5'. This spiralling flow imparts a force F to turbine 7 which has
components F.sub.R (drives the turbine in rotation) and F.sub.A
(imparts an upward movement to the turbine). Force F.sub.A, smaller
in magnitude than force F.sub.R, overcomes the influence of gravitational
forces on the turbine to cancel frictional forces which tend to
reduce F.sub.R at small delivery rates.
At turbulent speed, force F.sub.R is approximately proportional
to the square of the delivery of the input flow into the distributor.
To obtain a turbine rotation speed perfectly proportional to the
rate of flow--a requisite condition for the accuracy of the meter--it
is necessary to create a force opposite F.sub.R so that the resultant
of this force is directly proportional to the flow. This result
is generally achieved by the creation of a series of ribs or plateaus
11 on the bottom of cylindrical housing 1 as for example the star-shaped
pattern of ribs shown in FIG. 2. In a system such as the one described,
the flow within a housing 1 is divided, on the one hand, into a
spiral current H on the inner periphery of the distributor or housing
1 (illustrated by the stippled areas of FIG. 4), and, on the other
hand, into a central swirling zone M known as a Maelstrom zone.
The turbines used until now in multijet water meters comprise (see
FIGS. 1 and 5), radially directed blades 12 arranged concentrically
around a central hub 13 having rather large dimensions so as to
desirably occupy a substantially large volume or portion of the
Maelstrom zone and thus reduce the braking effect of that zone on
the rotational energy of the blades. Because of this, there are
frequently found serious disturbances in the hydraulic equilibrium
as previously described, and the desired result in the fluid flow
metering is not always achieved or is achieved in a very unstable
manner, which, in both cases, makes the metrologic stability of
the meter uncertain.
Referring now to FIGS. 6-14 the present invention comprises an
improved turbine for use with cylindrical housings of the type described
above and employed in conventional multi-jet fluid flow meters.
FIGS. 6 and 8 illustrate a first embodiment of the invention in
which turbine 14 unitarily comprises a thin disk 15 from which depend
several blades 16 and at the center of which is dependingly formed
an annular ring 17 in which a hollow rod 19 may be engaged for connection
to the counting device of the meter (not shown) via ribs or splines
carried by a shaft 18 of the rod. The central lug 8 of the distributor
housing of FIG. 1 is insertably received in the hollow rod 19 for
mounting turbine 14 on lug 8 in a manner analogous to the mounting
of the conventional turbine 7 on lug 8. One variation of the turbine
14 of the present invention shown in FIG. 6 is illustrated in FIG.
9 in which the ring or bearing 17 is disposed above disk 15 projecting
upwardly. Other variations of turbine 14 shown in FIG. 6 are illustrated
in FIG. 10a and FIG. 10b in which the connecting shaft is formed
integral with disk 15; in FIG. 10a, shaft 18 is secured to the upper
side of disk 15 and extends upwardly while in FIG. 10b, shaft 18
is secured to the underside of disk 15 and projects downwardly.
Most commonly, blade configuration 16 illustrated in FIGS. 6 and
8-10 is employed in the turbine of the present invention. However,
other configurations more adapted to certain flows and/or to various
types of fluid can be foreseen, are representatively shown, in a
nonlimiting way, in FIGS. 7a to 7e.
In practice, the number of vertical blades under the arm or carrier
disk can vary within reasonable limits. In the distributors of multi-jet
meters currently used and referred to in FIGS. 1 to 5 turbines
are equipped with seven blades for distributors having first and
second arrays of ten holes each. According to a characteristics
of the invention, the ratio between the number of holes and the
number of blades is preferably a whole number; for example, only
five blades (instead of seven) are provided for housings equipped
with ten perforations in each lower and upper array for the input
and output of the water.
Further, it has been found that in certain cases, the operation
of this turbine can be further improved by altering its configuration.
For example, the turbine according to the invention may be provided
on its surface with means that make it possible to brake or slow
its speed of rotation when very strong flows of fluid are involved.
In general, when such strong flow flows are involved, a blade-carrying
disk has a tendency to race and in the past, it has been necessary
to create, in some way, additional turbulences in the agitation
zone of the fluid to slow down the movement of this disk.
According to one embodiment, illustrated in FIG. 12 disk 15 is
advantageously pierced with holes 20 each of which are provided
in the space between two blades 16.
According to another embodiment, the braking or slowing means can
consist of ribs or projections located on the upper face of the
disk at a location coinciding with each of the blades in a concentric
fashion. According to yet another embodiment (shown in FIG. 14),
ribs 22 are provided on the lower face of disk 15 as a radially
inwardly directed extension of each blade. The combination of these
two systems can also be provided as yet another embodiment.
The use of a new turbine, according to the invention, on a conventional
distributor-housing (of the type in FIG. 1) makes it possible to
regulate the flow of measured fluid and to approach or attain an
ideal curve in the calculations of relative errors on the measurements
of flows of meters known to date. In this regard, FIG. 11 illustrates
the ordinary (5%) deviations or errors (E) or tolerated (2%) deviations
or errors (E) in relation to the flow of water Q in a multi-jet
meter at the levels of minimum flow (Q min), transition flow (Qt)
and nominal flow (Qn). Curve A symbolizes the operation of a multi-jet
meter of the prior art as described above. Curve B also illustrates
the case of a meter of the same type where all the optimum adjustments
have been made to reduce the margins of errors. Curve C, corresponding
to a minimized margin of error, was obtained by using a turbine
according to the invention, such as the one illustrated in FIG.
6. Further, by using a turbine designed according to the improvements
of FIGS. 12 and 13-14 an accurate curve of measurement at the various
flows can still be made linear, particularly in the case where it
would normally rise rapidly for a very high fluid flow.
Of course, without going beyond the scope of the original idea
of replacing the standard rotor with blades disposed around a central
hub with a flat disk equipped with radial blades, other advantageous
variant embodiments can be considered. For example, the thin disk
can be installed in the median zone, rather than in the top, of
the distributor housing the peripheral blades placed on both sides
of the disk. Or two disks may be mounted parallel to one another
and interconnected one to the other via, and made solid with, vertical
blades. These two embodiments can also prove very advantageous in
water meters of the type known as "single jet" meters.
It will be appreciated by those skilled in the art that various
other changes may be made without departing from the scope of the
invention, and the invention is not to be considered limited to
that which is shown in the drawings and described in the specification.
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