Abstrict A flow meter for measuring the volume of flowing fluid through
a conduit is provided with a self-centering rotor assembly that
becomes precisely centered within a flow chamber of the flow meter
upon assembly of the flow meter construction. Rotor support means
may be provided having cam surfaces defined thereon, which cam surfaces
have cooperative camming engagement with appropriate surfaces formed
on the rotor assembly and are adjusted during assembly of the rotor
mechanism to accomplish centering of the rotor mechanism within
the housing structure and to establish tight frictional engagement
with the inner wall structure of the housing to positively lock
the rotor assembly in its centered position within the flow chamber.
Claims What is claimed is:
1. A flow meter for measuring the volume of fluid flowing through
a conduit, said flow meter comprising:
a housing defining a flow chamber, said housing defining inlet
and outlet openings and having connection means for connection thereof
into said conduit;
rotor assembly means disposed within said flow chamber and having
a rotor element that is rotatable by the fluid flowing through said
flow chamber;
first centering means being provided on said rotor assembly means;
rotor assembly support means being disposed within said flow chamber
and engaging said housing, said rotor assembly support means engaging
said first centering means of said rotor assembly means; and
second centering means being defined by said rotor means and being
disposed within said flow chamber, said second centering means engaging
said rotor assembly support means and reacting with said first centering
means of said rotor assembly means to cause precise centering of
said rotor assembly means within said flow chamber.
2. A flow meter as recited in claim 1 wherein:
said rotor assembly support means includes a plurality of rotor
support elements having substantially equidistantly spaced contact
with both said housing and said rotor assembly means.
3. A flow meter as recited in claim 1 wherein:
said rotor assembly support menas have cam means defined thereon,
said cam means reacting with said first centering means of said
rotor means and said housing during assembly of said flow meter
to cause precise centering of said rotor means within said flow
chamber.
4. A flow meter as recited in claim 1 wherein:
said first centering means comprises second cam means being defined
on said rotor support means, said first and second cam means cooperatively
reacting during assembly of said flow meter for causing said centering
of said rotor means and for developing sufficient frictional contact
between said rotor support means, said rotor means and said housing
for maintaining said rotor means in firmly supported and centered
relation within said flow chamber.
5. A flow meter as recited in claim 1 wherein:
said flow chamber within said housing is defined in part by a pair
of spaced concentric cylindrical surfaces formed within said housing;
and
said centering means engaging said cylindrical surfaces and reacting
therewith to achieve axial positioning of said rotor means within
said flow chamber.
6. A flow meter as recited in claim 1 wherein:
said rotor means has a shaft defining an axis about which said
rotor element rotates;
adjustment means being carried by said shaft;
said first centering means comprising opposed first cam means being
supported by said shaft on opposite sides of said rotor element,
said first cam means being linearly movable upon movement of said
adjustment means; and
said second centering means comprising second cam means being formed
on said rotor assembly support means and reacting with said first
cam means upon movement of said adjustment means for causing movement
of said rotor means to the concentric position thereof within said
flow chamber and for developing sufficient frictional contact between
said rotor assembly support means, said rotor means and said housing
for maintaining said rotor assembly means in firmly supported and
centered relation within said flow chamber.
7. A flow meter as recited in claim 1 wherein:
said rotor means has a shaft defining an axis about which said
rotor element rotates;
a pair of centering elements are movably supported by said shaft
on opposite sides of said rotor element, said first centering means
comprising tapered cam surface means formed on said centering elements;
and
said rotor assembly support means comprise a plurality of support
vanes, said second centering means comprises cam surface means being
formed on each of said vanes and having mating engagement with said
cam surface means of said centering elements, said vanes engaging
said housing for retention of said rotor assembly means within said
housing and said cam surfaces cooperatively reacting to achieve
said centering of said rotor assembly means within said flow chamber.
8. A flow meter as recited in claim 7 wherein:
said centering elements have a plurality of slots formed substantially
equidistantly about the outer periphery thereof;
said first cam surface means comprise tapered cam surfaces defining
the bottom of each of said slots; and
said vanes being received within respective ones of said slots
with said cam surfaces of said vanes being disposed in camming engagement
with respective ones of said tapered cam surfaces at the bottom
of each of said slots.
9. A flow meter as recited in claim 7 wherein:
adjustment means, upon being manipulated, causes relative linear
movement of said centering elements and causes said cam surfaces
of said centering elements and said vanes to cooperatively react
to induce radial movement of said vanes, urging the outer portion
of said vanes into tight supporting engagement with said housing.
10. A flow meter as recited in claim 9 wherein:
said adjustment means comprises threads formed at one extremity
of said axial shaft and an adjustment nut being threadedly received
by said threads and, upon being rotated relative to said shaft,
causing said linear movement of said centering elements.
11. A flow meter for measuring the volume of fluid flowing through
a conduit, said flow meter comprising:
a housing defining a flow chamber, said housing defining inlet
and outlet openings and having connection means for connection thereof
into said conduit;
a rotor assembly being disposed within said flow chamber and having
a rotor element that is rotatable by fluid flowing through said
flow chamber;
first centering means being provided on said rotor assembly for
centering of said rotor assembly within said flow chamber;
rotor assembly support means being disposed within said flow chamber
and engaging said first centering means and said housing; and
second centering means being formed on said rotor assembly support
means and reacting with said first centering means to cause said
centering of said rotor assembly.
12. A flow meter as recited in claim 11 wherein:
said first centering means comprise a pair of spaced elements having
oppositely disposed cam surfaces formed thereon; and
said rotor assembly support means comprise a plurality of vane
elements being disposed in substantially equidistantly spaced relation
about said first centering means and said housing and being disposed
in rotor assembly supporting engagement with both said first centering
means and said housing.
13. A flow meter as recited in claim 11 wherein:
an elongated shaft is disposed within said flow chamber and defines
an axis about which said rotor element is rotatable;
said first centering means comprises a pair of hubs supported by
said elongated shaft and being disposed on either side of said rotor
means;
cam surface means being formed on each of said hubs and being disposed
in oppositely directed relation one with the other;
said rotor assembly supported means comprising a plurality of vane
elements each engaging said cam surface means and also engaging
said housing;
means for imparting controlled relative movement of said hubs on
said shaft; and
said rotor assembly support vanes cooperating with said cam surface
means, responsive to said controlled relative movement of said hubs,
to induce radial movement of said vanes to cause friction tight
supporting engagement between said vanes and said housing and between
said vanes and said hubs.
14. A flow meter as recited in claim 13 wherein:
said centering means is of elongated generally cylindrical configuration;
slot means is formed in said centering means generally equidistantly
about the periphery thereof;
said cam surface means comprises a plurality of elongated tapered
cam surfaces defining the bottom surfaces of each of said slots;
and
said vanes are disposed one within each of said slots and in engagement
with respective ones of said cam surfaces.
15. A flow meter as recited in claim 13 wherein:
said vane elements have tapered cam surfaces formed thereon and
having mating engagement with said cam surface means of said hubs,
said cam surfaces and said cam surface means cooperatively reacting
during linear movement of said hubs to impart said radial movement
to said vanes.
16. A flow meter as recited in claim 11 wherein:
an elongated shaft is disposed within said flow chamber and defines
an axis about which said rotor element is rotatable;
a rotor bearing is received about said elongated shaft and provides
rotatable support for said rotor element;
fluid flow directing elements are disposed on either side of said
rotor journal and bear against said rotor bearing; and
said rotor assembly support means engage said fluid flow directing
elements.
Description FIELD OF THE INVENTION
This invention relates generally to flow meters having internal
rotors that rotate responsive to the flow of fluid medium therethrough
and which provide signals corresponding to the volume of fluid flowing
through the meter mechanism. More particularly, the present invention
is directed to a novel flow meter construction wherein a rotor assembly
is properly positioned in axially centered relationship with the
housing structure by cooperative camming and support devices to
facilitate ease of assembly and to facilitate relatively low cost
manufacture.
BACKGROUND OF THE INVENTION
It is well known in the manufacture of most mechanical devices
that the degree of accuracy to which any mechanical device is constructed
may be controlled according to the tolerance level or margin of
error to which the various parts of the device are constructed.
Various matters, such as quality of surface finish, type of material,
character of heat treating, etc. are largely determinative not only
of the quality of the mechanical device, but also these factors
affect the cost of manufacturing of such devices. In fact, costs
of manufacturing in most circumstances appear to be reflected by
the character of manufacturing tolerances and materials to an exponential
degree. In other words, manufacturing costs rise exponentially with
improvement of the quality of most mechanical devices. In most circumstances,
however, there is a limit to the quality of any particular product,
depending upon the purchasers use of that particular product and
the price the purchaser is willing to pay for the product.
In the field of flow meter manufacture the foregoing holds true,
because manufacturing costs appear to be exponentially related to
the quality of machining operations, quality of bearings and other
parts as well as the quality of the material that is utilized in
the manufacturing process. It is desirable, however, to provide
a flow meter construction, especially for flowing liquid, that is
extremely sensitive to all conditions of flow and provides as accurate
a readout of the volume of flowing liquid as is practical. This
factor holds true regardless of the particular type of flow meter
involved.
Although the present invention may find effective application in
various types of flow meter constructions, for the purpose of simplicity
and to facilitate ready understanding of the present invention,
the invention will be set forth herein particularly as it relates
to turbine or axial fluid flow meters, especially suited for measuring
flowing liquid. Such flow meters typically utilize magnets or magnetically
attracted slugs that are radially disposed in a member that rotates
with the rotor and induces a magnetic flux (induction or variable
reluctance) in a fixed core spaced from and aligned with rotating
magnets or slugs. The magnetic flux induced in the core in turn
induces a signal in a coil wound about the core member which signal
is transmitted to appropriate registering equipment. The radial
displacement of the magnets from the rotational axis of the rotor
is small compared with the average radius through which the fluid
acts on the blades, thus enhancing the mechanical advantage of the
meter and providing extremely linear low flow rate and low pressure
preformance.
It is not intended, however, to restrict the present invention
to this particular application, it being obvious that the present
invention may be effectively employed in conjunction with different
flow meter devices as well as other mechanical devices having turbines
or rotors without departing from the spirit or scope hereof.
In the manufacture of turbine flow meters of the nature indicated
above, it is desired that the rotor assembly, including the rotatable
rotor element, be precisely centered within the bore or flow passage
of a flow meter housing structure and that the axis of the rotor
be oriented in precisely parallel relation to the linear direction
of fluid flow, to enhance the mechanical advantage of the meter
as much as possible to provide extremely linear low flow rate and
low pressure performance which are qualities that are especially
desired in both liquid and gas flow meters. To accomplish precise
centering of the rotor assembly and to insure precisely parallel
relationships between the axis of the flow meter and the flow of
fluid through the meter assembly, it is typically required that
spaced high quality precisely concentric surfaces be machined in
a flow meter housing structure, which surfaces receive rotor assembly
support elements to support the rotor assembly in positive relation
to these concentric surfaces.
It is also necessary that the concentric surface be of precisely
the same dimension so that each of the typically spaced rotor support
devices may be precisely related to one another. Machining operations
necessary to produce the high quality concentric and precisely sized
cylindrical surfaces within flow meter housing causes the development
of rather high manufacturing costs, but such costs, prior to development
of the present invention, were deemed to be warranted in view of
the desirability to provide a high quality flow meter construction
having optimum low pressure performance capabilities. High costs
of such machining operations is typically considered a necessity.
Accordingly, it is a primary object of the present invention to
provide a novel flow meter construction incorporating a simple and
efficient mechanism for achieving precise centering of a rotor assembly
relative to a flow passage in a rotor housing structure, which does
not necessitate the provision of high quality high cost machining
operations.
It is a further object of the present invention to provide a novel
flow meter construction wherein concentric bores or cylindrical
surfaces may be formed in a flow meter housing by relatively low
cost machining operations without sacrificing from the standpoint
of accuracy in concentricity or positioning of the rotor within
the housing structure.
It is also an object of the present invention to provide a novel
flow meter construction wherein concentricity and positive alignment
of the rotor assembly within a flow meter housing may be effectively
maintained even though the spaced bores engaged by the flow meter
supports are of different dimension.
Among the several objects of the present invention is noted the
contemplation of a novel flow meter construction having means for
supporting a rotor assembly within a flow meter housing, which means
react with the rotor assembly and with the housing structure to
achieve precise centering and positioning of the rotor assembly
during assembly of the flow meter construction.
It is another important object of the present invention to provide
a novel flow meter construction wherein the internal parts of the
flow meter construction including the rotor, the rotor assembly
and the rotor assembly support system may be quickly and simply
placed within a flow meter housing structure by relatively inexperienced
personnel and may be quickly locked into precise assembly simply
by simple adjustment.
It is an even further object of the present invention to provide
a novel flow meter construction including an internal rotor assembly
and rotor support mechanism that may be quickly and simply disassembled
through the use of simple tools for purposes of repair or replacement
of the internal parts of flow meters and other similar mechanical
devices.
It is also an object of the present invention to provide a novel
flow meter construction that may be repaired or adjusted in the
field without any requirement for the use of specialized tools for
disassembly or assembly thereof.
Other and further objects, advantages and features of the invention
will become obvious to one skilled in the art upon an understanding
of the illustrative embodiments about to be described and various
advantages, not referred to herein, will occur to one skilled in
the art upon employment of the invention in practice.
SUMMARY OF THE INVENTION
Flow meters, such as turbine flow meters particularly described
herein, may comprise a housing that is formed to define a flow chamber
with inlet and outlet openings being in communication with the flow
chamber. A rotor assembly is disposed within the flow chamber which
incorporates a freely rotatable rotor supporting at least one magnet
that induces a magnetic field in a coil carried by the flow meter
housing for generation of an electrical signal each time the magnet
moves in close proximity to the coil during rotation of the rotor.
The rotor assembly also incorporates flow directing elements on
either side of the rotor which are supported by a shaft that also
forms an axis for the rotor causing the fluid to change in pressure
and velocity as it flows to and from the turbine rotor element.
Centering elements are also supported by the axial shaft which are
linearly movable relative to the axis and relative to the rotor.
Rotor support means is disposed within the flow chamber and engages
both the housing structure and the spaced elements supported by
the axial shaft to support the rotor assembly within the flow chamber
of the housing. The spaced centering elements and the rotor assembly
support means are provided with cooperative cam energized centering
vanes that causes the axial shaft supporting the rotor assembly
and rotor to be precisely centered and axially aligned within the
flow chamber of the housing during assembly of the flow meter mechanism.
The spaced rotor centering elements carried by the axial shaft
may take the form of generally cylindrical elements having slots
formed therein, which slots are spaced substantially equidistantly
about the periphery of the cylindrical centering elements. The bottom
surfaces of the slots taper downwardly and inwardly toward the rotor
and define cam surfaces. A plurality of plate like vanes may be
disposed within the flow chamber and may be received within respective
slots of the elongated rotor support elements. Tapered cam surfaces
may be formed on the vane elements which have cooperative engagement
with the inwardly and downwardly tapered cam surfaces of the elongated
rotor support and centering elements and which cause reaction during
movement of the elongated rotor support and centering elements toward
one another to cause simultaneous and equal radially outward movement
of the vane elements toward the wall structure of the housing. After
contact is made between the vane elements and the housing, continued
cam reaction between the tapered cam surfaces of the elongated rotor
support and centering elements and the vane elements will induce
the rotor assembly to become precisely centered relative to the
flow chamber of the housing and continued movement of the elongated
rotor support elements toward one another will, through cooperative
camming relationship between the tapered surfaces of the rotor support
elements and the vanes, cause sufficient frictional contact to be
developed between the vane elements and the housing structure and
between the vane elements and the rotor assembly support elements
to positively lock the rotor assembly relative to the housing structure.
A single adjustment mechanism such as an adjustment nut may be
received by the axial shaft and may be manipulated to cause the
elongated rotor support elements to move toward one another during
assembly of the flow meter construction to develop the force required
for centering and locking of the rotor assembly within the housing
of the flow meter.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the manner in which the above recited advantages
and objects of the invention are attained, as well as others, which
will become apparent, can be understood in detail, more particular
description of the invention, briefly summarized above, may be had
by reference to the specific embodiments thereof that are illustrated
in the appended drawings, which drawings form a part of this specification.
It is to be understood, however, that the appended drawings illustrate
only typical embodiments of the invention and are therefore not
to be considered limiting of its scope, for the invention may admit
to other equally effective embodiments.
IN THE DRAWINGS
FIG. 1 is a sectional view of a flow meter constructed in accordance
with the present invention, which sectional view is taken along
line 1--1 in FIG. 2.
FIG. 2 is a transverse sectional view of the flow meter construction
illustrated in FIG. 1 which transverse sectional view is taken
along line 2--2 in FIG. 1.
FIG. 3 is a sectional view of a flow meter construction representing
a modified embodiment of the present invention, which sectional
view is taken along line 3--3 in FIG. 4.
FIG. 4 is a transverse sectional view of the flow meter construction
illustrated in FIG. 3 which transverse sectional view is taken
along line 4--4 of FIG. 3.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
Now referring to the drawings and first to FIG. 1 there is depicted
a flow meter, illustrated generally at 10 having a housing 12 provided
with end connections 14 and 16 that are each appropriately provided
with a plurality of bolt holes 18 to enable the housing structure
to be secured by bolts or threaded studs to appropriate flanges
of a conduit in which the flow meter may be disposed.
A flow chamber is defined within the housing 12 by generally cylindrical
bores 22 and 24 that are spaced by a reduced diameter bore 26 that
defines opposed shoulders 28 and 30. The cylindrical surfaces 22
24 and 26 are disposed in concentric relation and, although the
cylindrical surfaces 22 and 24 are concentric one with the other,
they need not be of the same dimension. As explained above, ordinarily
it is required that opposed cylindrical surfaces provided for support
of a rotor mechanism be of precisely the same dimension. And, as
also noted, machining operations that develop such precision surfaces
are quite expensive and represent a large part of the overall cost
of such flow meters. The present invention effectively eliminates
the need for the surfaces 22 and 24 to be of the same dimension
and therefore effectively eliminates a substantial portion in manufacturing
cost that would otherwise be required by providing high quality
machined concentric surfaces of precisely the same dimension.
A flow directing ring 32 may be disposed within the flow chamber
20 and may be in loosely received relation within the bore 22 with
one side of the outer peripheral portion of the ring disposed in
supported contact with the annular shoulder 28. The flow directing
ring 32 may have a frustoconical surface 33 serving to direct flowing
fluid to the blades of a rotor of the meter and to prevent flowing
fluid from being directed against the ring-like outer portion of
the rotor. A centerally located upstream flow directing element
34 may be provided that is of slightly greater axial dimension as
compared to the axial dimension of the ring and may have an axial
bore 36 formed through the center portion thereof which may be extended
an axial shaft 38. The axial extremities of the flow directing element
34 may define generally planar surfaces 40 and 42 each extending
slightly beyond the respective axial extremities of the flow directing
ring. A circular flat thrust bearing element 44 may be received
in a recess formed in the center portion 34 of the flow directing
element in such manner that the outer surface of the bearing element
is substantially co-planar with the planar surface 42. Bearing 44
may be formed of carbide or any other suitable bearing material
having good wear characteristics.
A rotor element 46 will be rotatably disposed within the flow chamber
20 and may be provided with an outer rimmed portion 48 within which
may be supported one or more magnet elements 50 that, at specific
points during rotation of the rotor element 46 move into juxtaposition
with a pick-up element 52 of a coil 54 thereby inducing in the
pick-up coil signal impulses which may either be counted for securing
an indication of the flow rate of the stream, or may be utilized
for securing a direct current voltage proportional to the rate of
rotation of the rotor, and hence to the rate of flow of the stream.
Since both methods of utilizing the impulses are well known commercially
and neither forms a part of the present invention, the mechanism
for securing these results is not depicted in the drawings and will
not be described herein. The housing 12 of the flow meter construction
will be constructed of any suitable non-ferous material, thereby
allowing magnetic flux of the magnet 50 to be induced through the
wall structure of the housing 12 where it is inductively detected
by the coil 54.
A downstream rotor positioning and flow controlling element 56
may be provided having an axial bore 58 formed therethrough which
bore also receives the shaft 38 and the rotor positioning element
56 may also have a pair of generally planar surfaces 60 and 62 formed
thereon. An annular washer-like thrust bearing element 64 similar
to thrust bearing 44 may be received within an appropriate recess
formed in the rotor positioning element 56 with the outer surface
of the bearing element also disposed in generally co-planar relation
with the planar surface 60. A bearing bushing 66 may also be received
by the axial shaft 38 and may be disposed in bearing engagement
with a journal 68 that defines the axial center of the rotor 46.
The extremities of the bearing bushing 66 may be disposed in engagement
with the appropriate thrust bearings 44 and 64 to properly dispose
the rotor 46 in spaced relationship with the upstream flowing directing
element 34 and with the downstream flow directing element 56. As
flowing fluid passes through the flow chamber 20 of the meter the
upstream flow directing element 34 will function with the conical
surface 33 of the flow directing ring 32 to cause increase in velocity
of the fluid stream together with consequent reduction in pressure
in the vecinity of the rotor 46. This venturi effect enhances accuracy
and efficiency of meter operation.
It will be desirable to retain the rotor mount assembly in precisely
axially centered relationship within the flow chamber 20 disposing
the axial shaft 38 in precisely co-axial relationship with the cylindrical
surfaces 22 and 24 of the housing. One suitable means for accomplishing
centering of the rotor assembly may conveniently take the form illustrated
in FIGS. 1 and 2 where a pair of elongated centering elements 70
and 72 are provided, each having axial bores 74 and 76 respectively,
that receive the axial shaft 38 in movable relation therewith. The
centering elements 70 and 72 may be of generally identical configuration,
if desired, and as shown in FIG. 2 may be of generally cylindrical
outer configuration. A plurality of slots 78 80 and 82 may be formed
in each of the centering elements which slots may be disposed to
receive vane type centering and locking elements 84 86 and 90
respectively. The bottom surface of each of the slots 78 80 and
82 may be tapered as shown at 92 thereby providing cam surfaces
that are disposed in mating relationship with respective cam surfaces
formed on the vane elements, such as shown at 94 in FIG. 1.
The cam surfaces 94 of the vanes are oppositely tapered with respect
to the tapered cam surfaces defining the bottom of each of the slots
thereby cooperating with the surfaces 92 upon linear movement of
the centering elements 70 and 72 relative to the axial shaft 38
to induce radial movement to the respective vane elements 84 86
and 90. The centering elements and vane elements at each extremity
of the shaft 38 are positioned to be oppositely tapered, thereby
causing all of the vane elements at each extremity of the shaft
to be moved radially and simultaneously outward upon linear movement
of the centering elements 70 and 72 toward one another. It should
also be borne in mind that radially outward portion of the vane
elements will be in engagement with the cylindrical surfaces 22
and 24 to provide structural support between the centering elements
and the housing for the entire rotor assembly.
In order to achieve adjustment of the centering elements 70 and
72 relative to the shaft 38 a cap 96 may be non-rotatably secured
to one extremity of the shaft 38 such as by threading or the like,
which cap may be provided with a slot 98 to facilitate engagement
by a tool such as a screwdriver in order to prevent rotation of
the cap and shaft during assembly and disassembly of the rotor mechanism.
At the opposite extremity of the shaft 38 may be provided adjustment
threads 100 which receive an adjustment nut 102 that bears against
an adjustment washer 104. As the cap 96 is held immovable by means
of a screwdriver engaging the slot 98 a simple wrench may be engaged
with the adjustment nut 102 and the adjustment nut may be rotated
in such a manner as to drive the centering elements 70 and 72 toward
one another. When this occurs, the corresponding tapered cam surfaces
92 and 94 on the centering devices and vanes, respectively, will
cooperatively react, thereby inducing radial movement to the vanes.
As the vanes move radially outward they react against the cylindrical
surfaces 22 and 24 causing centering movement of the axial shaft
38 and all of the components supported by the shaft. Since the surfaces
22 and 24 are concentric, centering movement of each extremity of
the shaft 38 with respect to the surfaces 22 and 24 will result
in precise centering of the entire rotor assembly within the flow
chamber of the housing. If the surfaces 22 and 24 are of different
dimension but are yet concentrically oriented, the vanes will simply
center each extremity of the shaft relative to the respective cylindrical
surface and the entire rotor assembly will be accurately centered.
ASSEMBLY
With the flow directing ring 32 disposed in the position illustrated
in FIG. 1 with the downstream portion thereof in engagement with
or near the annular shoulder 28 the axial shaft 38 with the lock
nut 102 and washer 104 removed, will be inserted through the axial
bore 74 of the centering element 70 and the vane elements 84 86
and 90 will be disposed as shown at the left hand portion of FIG.
1 being received loosely within the slots of the centering element.
The axial shaft 38 with the centering element 70 and the vanes
will be inserted into the flow chamber and the centering element
will be shifted relative to the vanes to cause the vanes to move
radially into engagement with the cylindrical surface 22 due to
the reaction of the cam surfaces of the centering element and vanes.
The downstream edges of the vanes 84 86 and 90 will be in spaced
relation with the shoulder defined by the upstream portion of the
flow directing ring 32. The upstream flow directing element will
then be inserted onto the shaft and will be moved toward the centering
element 70 until the stop shoulder 40 contacts the downstream edges
of the vanes.
After this has been accomplished, the rotor element 46 with the
bearing bushing 66 in place as shown will be inserted onto the shaft
38 and will be moved substantially to the position illustrated in
FIG. 1 with the bushing 66 contacting the thrust washer 44. The
downstream rotor positioning element 56 will then be received by
the shaft and will be moved substantially to the position illustrated
in FIG. 1 with the thrust washer 64 in engagement with the bushing
66. The downstream centering element 72 with the vanes emplaced
within the respective grooves or slots thereof, will be then received
by the shaft 38 and will be moved to the left sufficiently to bring
the upstream edges of the vanes into engagement with the downstream
surface 62 of the flow directing element 56. When this has been
accomplished, the washer 104 will be emplaced and the adjustment
nut 102 will be threaded onto the shaft 38 and will be manipulated
while maintaining the cap 96 and shaft 38 in immovable relation
with a screwdriver or other such tool. The adjustment nut, upon
being rotated, will urge all of the parts into intimate bearing
contact and, after having done so, will upon further rotation, through
cooperative relationship between the cam surfaces 92 and 94 achieve
radial movement of the vane elements, thereby moving the vane elements
into tight frictional contact with the bores or cylindrical surfaces
22 and 24 defining the internal wall structure of the housing 12.
After the adjustment nut has been sufficiently rotated to achieve
sufficient frictional contact with the surfaces 22 and 24 to cause
positive locking of the rotor assembly within the housing structure,
a conventional cotter key 106 or other such locking device may be
inserted through corresponding apertures in the adjustment nut and
shaft 38 thereby locking the adjustment nut in immovable relation
with the shaft. Disassembly of the flow meter mechanism will occur
in opposite sequence to the assembly procedure set forth above.
Referring now to FIGS. 3 and 4 a modified embodiment of the present
invention is illustrated that functions in the same manner as indicated
above in connection with FIGS. 1 and 2. Like reference numerals
will indicate like parts in the two modified embodiments that are
shown. As illustrated in FIG. 3 a generally cylindrical flow meter
body structure 12 is provided that is similar to the flow meter
body 12 shown in FIG. 1 with the exception that seal recesses are
provided at each of the connection flanges of the body and the body
structure is provided with internally tapered surfaces defining
inlet and outlet openings into the flow chamber defined within the
housing. Generally cylindrical internal bores 22 and 24 are defined
within the housing 12 and cooperate with a reduced diameter generally
cylindrical surface 26 to define the flow chamber 20 for conducting
flow fluid through the meter structure. The generally cylindrical
surfaces 22 24 and 26 are concentrically related and although surfaces
22 and 24 are illustrated as being of the same dimension, it is
not necessary that they be of the same dimension. Juncture between
the cylindrical surfaces 22 and 24 with the smaller diameter surface
26 defines annular shoulders 28 and 30.
An annular flow directing ring 32 is received within the cylindrical
bore 22 and rests against the shoulder 28. Ring 32 is provided with
a frusto-conical surface 33 that serves to direct the flow of fluid
through the vanes of the rotor 46 thereby preventing the flowing
fluid from impinging upon the ring like outer portion 48 of the
rotor.
A shaft 110 may be disposed within the flow chamber 20 and may
provide an axis about which the rotor 46 is rotatable. The axial
shaft 10 will, in the properly aligned position of the various parts
within the flow chamber, be disposed in parallel relation with the
cylindrical surfaces 22 and 24 and will be precisely centered and
concentric with respect to the cylindrical surfaces. The elongated
shaft 110 may be provided with threaded extremities 112 and 114
that may receive adjustment nuts 116 and 118 respectively that may
be secured in place by means of cotter keys 117 and 119 respectively.
For the purpose of establishing a rotatable relationship between
the rotor 46 and the shaft 110 a bushing 66 may be disposed about
the shaft and may receive a sleeve like bearing journal 68 that
is provided to define the center of the rotor 46. The bushing and
journal 66 and 68 may be composed of carbide or any other suitable
bearing material within the spirit and scope of the present invention.
Thrust forces against the bushing 66 which is slightly longer in
axial direction than the journal 68 may be received by washer like
thrust bearings 44 and 64 that are received within respective recesses
formed in fluid flow controlling elements 34 and 56 respectively.
Flow controlling element 34 is disposed on the upstream side of
the rotor element and cooperates with the frusto-conical surface
33 to cause fluid flowing through the flow meter to increase in
velocity with consequent reduction in pressure in the area of the
rotor 46. The downstream flow controlling element 56 allows the
flowing fluid to decrease in velocity as it flows toward the outlet
opening of the valve construction. The thrust washers 44 and 64
may also be composed of carbide or some other suitable thrust bearing
material.
For the purpose of causing centering of the shaft 110 within the
cylindrical bores 22 and 24 a pair of centering elements 120 and
122 may be received by the shaft 110 and may be of generally identical
construction, thereby allowing the centering elements to be utilized
both as upstream and downstream centering devices. The respective
leading and trailing extremities of the centering elements are of
curved configuration to reduce the flow resistance thereof to a
minimum. As shown in detail in FIG. 4 each of the centering elements
may be provided with a plurality of elongated slots 124 126 and
128 each having bottom walls that taper radially inwardly toward
the rotor element. Each of the bottom walls is substantially flat,
thereby defining a relatively flat cam surface that is disposed
for engagement by mating cam surfaces defined on a plurality of
vane elements 84 86 and 90 that contact both the centering elements
and the cylindrical walls 22 and 24 respectively to cause the rotor
assembly to be positively retained within the housing structure
in the same manner as described above in connection with FIGS. 1
and 2.
The structure set forth in FIGS. 3 and 4 is assembled in the same
manner as described above in connection with FIGS. 1 and 2 with
the exception that one of the adjustment nuts such as shown at 116
is placed on the shaft 110 in properly oriented manner and is locked
with respect to the shaft by means of the cotter key 117. The parts
are then brought into assembly in a manner discussed above with
the adjustment nut 118 being the last element received by the shaft
110. Threading of the adjustment nut 118 into its proper position
relative to the shaft will cause the centering elements 120 and
122 to be drawn toward one another, thereby causing inter action
between the cam surfaces of the centering elements and the cam surfaces
of the vanes, causing the vanes to be moved radially outwardly into
friction tight locking engagement with the cylindrical walls 22
and 24 of the housing structure.
In view of the foregoing, it is evident that I have provided a
novel flow meter mechanism that effectively accomplishes efficient
precise centering of a rotor mechanism within a flow chamber even
though relatively low cost machining operations have been involved
in machining internal rotor support surfaces in the housing. By
employing the simple rotor centering mechanism of the present invention,
each extremity of the rotor assembly is precisely centered relative
to the cylindrical bore within which it is disposed. Even though
the cylindrical bores are of different dimension the rotor assembly
will be precisely centered as long as each of the bores are concentrically
related. The vanes, having cam surfaces formed thereon and reacting
with respective ones of the centering elements 70 and 72 will be
urged radially outwardly until firm friction type contact is established
with the particular cylindrical surface involved and friction tight
contact will be established simultaneously at each extremity of
the housing structure regardless of the differing dimension that
might exist between surfaces 22 and 24 as long as the cylindrical
surfaces 22 and 24 are concentrically related.
I have also provided a novel flow meter mechanism that may be very
simply and efficiently assembled by relatively inexperienced assembly
personnel because of the simplicity of the assembly procedure, thereby
further promoting the low cost aspect of the present invention.
Moreover, the uniqueness and simplicity of construction and the
ease of assembly efficiently promote the capability for field servicing
even though it may be desirable to replace virtually all of the
internal parts of the flow meter assembly. It is apparent therefore
that the present invention is one well adapted to attain all of
the objects hereinabove set forth together with other advantages
which will become obvious and inherent from the description of the
apparatus itself. It will be understood that certain combinations
and subcombinations are of utility and may be employed without reference
to other features and subcombinations. As many possible embodiments
may be made of this invention without departing from the spirit
or scope thereof it is to understood that all matters herein set
forth or shown in the accompanying drawings are to be interpreted
as illustrative and not in a limiting sense. |