Note: Descriptions are shown in the official language in which they were submitted.
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CONTROL CAGE ASSEMBLY
FOR CENTRIFUGAL BLAST WHEEL MACHINE
BACKGROUND OF THE DISCLOSURE
1. Field of the Disclosure
The present disclosure relates generally to abrasive blast wheels and methods
for
cleaning or treating surfaces of work pieces, and more particularly to a
control cage
assembly for a centrifugal blast wheel machine and to methods of assembling
centrifugal
blast wheel machines.
2. Discussion of Related Art
Centrifugal blast wheel machines generally include a rotatable wheel having a
plate or a pair of spaced plates that carry radially extending blades.
Particulate matter is
discharged from a center of the blast wheel onto rotating surfaces of the
blades, which
propel the particulate matter against surfaces of a work piece to be cleaned
or treated.
Specifically, blast media is fed from a feed spout into a rotating impeller
situated within a
control cage at the center of the blast wheel. The media is fed from the
impeller, though
an opening in the control cage, and onto the heel or inner ends of the
rotating blades. The
media travels along the faces of the blades and is thrown from the tips of the
blades at the
work piece surfaces to be treated.
In certain embodiments, unwanted media blasts directed towards a housing of
the
centrifugal blasting wheel machine can harm a liner system provided on the
housing.
There is a need for a system to prevent accidental blasting into the housing
that cause
potential failures in the liner system as witnessed with conventional cast
liner.
SUMMARY OF THE DISCLOSURE
One aspect of the disclosure is directed to a centrifugal blast wheel machine
comprising a wheel assembly having a plurality of blades configured to throw
blast
media introduced into the wheel assembly against a work piece, and an impeller
positioned about an axis of the wheel assembly. In one embodiment, the
impeller has a
media inlet at one end adapted to receive blast media and a plurality of
impeller media
outlets constructed and arranged to allow egress of blast media upon rotation
of the
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impeller. The machine further comprises a motor coupled to the impeller to
drive the
rotation of the impeller and the wheel assembly, and a control cage assembly
surrounding
the impeller and secured to the wheel assembly. The control cage assembly
includes a
control cage having a cylindrical wall defining an interior chamber and a
media outlet
formed in the cylindrical wall to allow the egress of blast media from the
interior
chamber, a locking ring secured to a peripheral edge of the cylindrical wall,
the locking
ring including an indicator projecting radially outwardly from the locking
ring, and an
adaptor plate secured to the wheel assembly. The adaptor plate includes a
central
opening configured to receive the cylindrical wall of the control cage therein
and at least
one recess formed therein configured to receive the indicator when securing
the locking
ring and the control cage to the adaptor plate. The adaptor plate further
includes a
retaining ring configured to be secured to the adaptor plate and to firmly
secure the
locking ring and the control cage in place.
Embodiments of the machine further may include the adaptor plate having a
circumferential recess formed therein. The circumferential recess may be
configured to
receive the locking ring therein. The at least one recess of the adaptor plate
may extend
outwardly from the circumferential recess, The at least one recess may include
a range of
movement of the control cage within the locking ring. The range of movement
may be
color coded. The at least one recess further may act as a positive stop for
the indicator
needle to prevent further rotational movement of the locking ring beyond a
recommended
setting. The locking ring may freely float between the retaining ring and the
adaptor
plate until the retaining ring is secured in place.
Another aspect of the disclosure is directed to a control cage assembly for a
centrifugal blast wheel machine. In one embodiment, the control cage assembly
comprises a control cage having a cylindrical wall defining an interior
chamber and a
media outlet formed in the cylindrical wall to allow the egress of blast media
from the
interior chamber, and a locking ring secured to a peripheral edge of the
cylindrical wall.
The locking ring includes an indicator projecting radially outwardly from the
locking
ring. The control cage assembly further comprises an adaptor plate secured to
the wheel
assembly. The adaptor plate including a central opening configured to receive
the
cylindrical wall of the control cage therein and at least one recess formed
therein
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configured to receive the indicator when securing the locking ring and the
control cage to
the adaptor plate. The control cage further comprises a retaining ring
configured to be
secured to the adaptor plate and to firmly secure the locking ring and the
control cage in
place.
Embodiments of the control cage further may include the adaptor plate having a
circumferential recess formed therein. The circumferential recess may be
configured to
receive the locking ring therein. The at least one recess of the adaptor plate
may extend
outwardly from the circumferential recess. The at least one recess may include
a range of
movement of the control cage within the locking ring. The range of movement
may be
color coded. The at least one recess further may act as a positive stop for
the indicator
needle to prevent further rotational movement of the locking ring beyond a
recommended
setting. The locking ring may freely float between the retaining ring and the
adaptor
plate until the retaining ring is secured in place.
Yet another aspect of the disclosure is directed to a method of assembling a
centrifugal blast wheel machine. In one embodiment, the method comprises:
providing a
control cage having a cylindrical wall having an interior chamber and a media
outlet
formed in the cylindrical wall to allow the egress of blast media from the
interior
chamber; securing a locking ring to a peripheral edge of the cylindrical wall,
the locking
ring including an indicator projecting radially outwardly from the locking
ring; securing
an adaptor plate to the wheel assembly, the adaptor plate including a central
opening
configured to receive the cylindrical wall of the control cage therein and at
least one
recess formed therein configured to receive the indicator when securing the
locking ring
and the control cage to the adaptor plate; positioning the control cage having
the locking
ring on the adaptor plate, and securing a retaining ring to the adaptor plate
to secure the
locking ring and the control cage in place.
Embodiments of the method further may include the adaptor plate having a
circumferential recess formed therein, the circumferential recess being
configured to
receive the locking ring therein. The at least one recess further may include
a range of
movement of the control cage within the locking ring. The range of movement
may be
color coded. The at least one recess further may act as a positive stop for
the indicator
needle to prevent further rotational movement of the locking ring beyond a
recommended
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setting. The locking ring may freely float between the retaining ring and the
adaptor
plate until the retaining ring is secured in place.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are not intended to be drawn to scale. In the
drawings, each identical or nearly identical component that is illustrated in
various
figures is represented by a like numeral. For purposes of clarity, not every
component
may be labeled in every drawing. In the drawings:
FIG. 1 is a perspective view of a portion of a centrifugal blast wheel
machine;
FIG. 2 is another perspective view of the centrifugal blast wheel machine;
FIG. 3 is an exploded perspective view of the centrifugal blast wheel machine;
FIG. 4 is a perspective view of a feed spout having a clamp;
FIG. 5 is a perspective view of a control cage assembly of the present
disclosure;
FIG. 6 is another perspective view of the control cage assembly;
FIG. 7 is a front view of the control cage assembly;
FIG. 8 is a cross-sectional view of the control cage assembly;
FIG. 9 is an exploded perspective view of the control cage assembly; and
FIG. 10 is an enlarged front view of an indicator or the control cage
assembly.
DETAILED DESCRIPTION
Embodiments of the present disclosure are directed to a control cage assembly
configured to permanently indicate a correct blast pattern (also called "hot
spot") through
a control cage as set by the manufacturer. The control cage assembly further
is
configured to prevent an incorrect blast pattern setting through the control
cage as
currently possible on existing control cage designs. The control cage assembly
is
designed to prevent inaccurate settings when locking the control cage in
place.
The control cage assembly further prevents substandard blast wheel performance
resulting from the incorrect user setting of the control cage/hot spot. This
is achieved by
providing a color coded reference point into a specific area that is machined
or recessed
in a control cage adaptor plate combined with the indicator attached to (or
machined in) a
locking ring. The assembly includes an outer control cage retaining ring fixed
to the
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control cage adaptor plate on which the control cage is fixed into the control
cage locking
ring. The locking ring will freely float between the retaining ring and the
adaptor plate
until at such time the retaining ring is fastened into place applying pressure
on the
locking ring, securing it and the control cage into place. A noted feature of
the control
cage assembly is the indicator needle attached onto the locking ring that will
be nested
into the color coded recess formed in a control cage adaptor plate. The color
coded
recess further acts as a positive stop for the indicator needle to prevent
further rotational
movement of the locking ring (which controls the control cage) beyond a
recommended
setting.
Referring to the drawings, and more particularly to FIGS. 1-3, a centrifugal
blast
wheel machine is generally indicated at 10. In one embodiment, the centrifugal
blast
wheel machine 10 includes a housing, generally indicated at 12, which is
designed to
house the components of the centrifugal blast wheel machine. The centrifugal
blast
wheel machine 10 further includes a rotating impeller 14 supported by the
housing 12, a
control cage assembly, generally indicated at 16, which surrounds the
impeller, and a
wheel assembly, generally indicated at 18, which receives the control cage
assembly. A
motor 20 is provided to drive the rotation of the impeller 14 and the wheel
assembly 18.
The arrangement is such that blast media is fed from a feed spout into the
rotating
impeller 14, which is driven by the motor 20. By contact with vanes of the
rotating
impeller 14 (as well as with other particles of media already in the
impeller), blast media
particles are accelerated, giving rise to a centrifugal force that moves the
particles in
radial direction, away from the axis of the impeller. The particles, now
moving in a
generally circular direction as well as outwards, move through openings formed
in the
impeller 14 into a space between the impeller and a control cage of the
control cage
assembly 16, still being carried by the movement of the impeller vanes and the
other
particles.
When the particles that have passed though the impeller openings into the
space
between the impeller 14 and the control cage reach an opening provided in the
control
cage, rotational and centrifugal forces move the particles through the opening
and onto
ends of the vanes. The control cage assembly 16 functions to meter a
consistent and
appropriate amount of blast media onto the blades of the wheel assembly 18. As
the
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vanes of the impeller 14 rotate, the particles are moved along their lengths
and accelerate
until they reach the ends of the vanes and thrown from the ends of the vanes.
Although
the impeller 14 is shown to be cylindrical in shape, the size and thickness of
the impeller
may vary depending on the size of a blast wheel assembly and the desired
performance
characteristics. For example, the impeller 14 may have interior or exterior
walls that
taper in either direction along its axis. Typically, the impeller will be made
of a ferrous
material, such as cast or machined iron or steel, although other materials may
also be
appropriate. In one particular embodiment, the impeller is formed of cast
white iron.
The wheel assembly 18 of the centrifugal blast wheel machine 10 includes a hub
or wheel 24 and a plurality of blades, each indicated at 26, to throw blast
media
introduced into the wheel assembly to treat the work piece contained within
the housing
12. The arrangement is such that the impeller 14 is positioned about an axis
of the wheel
24 of the wheel assembly 18, with the impeller having a media inlet at one end
adapted to
receive blast media and a plurality of impeller media outlets constructed and
arranged to
allow egress of blast media upon rotation of the impeller. The control cage of
the control
cage assembly 16 surrounds the impeller 14 in a position in which the media
outlet of the
control cage assembly is adapted for passage of blast media to the heel ends
of the blades
of the blast wheel assembly 18. As mentioned above, the motor 20 is coupled to
the
impeller 14 and to the wheel assembly 18 to drive the rotation of the impeller
and the
wheel assembly.
Referring to FIGS. 5 and 6, the present disclosure is directed to the control
cage
assembly 16 for the abrasive blast wheel assembly 18 that is configured to
lock a control
cage of the control cage assembly in place. In one embodiment, the control
cage
assembly 16 of the present disclosure includes a control cage 28 having a
cylindrical wall
30 forming a housing defining an interior chamber and a media outlet for
allowing the
egress of blast media from the interior chamber. A typical centrifugal blast
wheel
machine 10 having a control cage 28 is used to treat a surface (not shown) of
a work
piece by projecting blast media (not shown) at the surface. The treatment may
be in the
nature of cleaning, peening, abrading, eroding, de-burring, de-flashing, and
the like, and
the blast media typically consists of solid particles such as shot, grit,
segments of wire,
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sodium bicarbonate, or other abrasives, depending on the surface being treated
and/or the
material being removed from the surface.
The control cage 28 of the control cage assembly 16, typically formed of cast
iron, is positioned concentrically around impeller 14 and, is approximately
cylindrical in
shape. Like the impeller 14, however, the control cage 28 may have other
shapes, and
may, for example, taper internally and/or externally in either direction along
its axis. The
control cage 28 also includes an outer flange or locking ring 34, which mates
with an
adaptor plate 36, which in turn is mounted on the wheel 24 of the wheel
assembly 18,
fixing the control cage with respect to the wheel and preventing the control
cage from
rotating with respect to the wheel upon operation of the blast wheel assembly
10. A
retaining ring 38 is further provided to firmly secure the locking ring 34 and
to prevent
the rotational movement of the control cage 28 with respect to the adaptor
plate 36 after
securing the adaptor plate to the blast wheel 24 of the blast wheel assembly
18. The
control cage 28 is then locked in place by placing the feed spout 22 onto the
control cage
and by firmly securing a feed spout 54, which is shown in FIG. 4.
In other embodiments, the control cage 28 may be restrained from movement by
attachment to other stationary elements of the blast wheel assembly 18 or its
(as indicated
above) environment, or, in some cases, may be allowed to or made to rotate in
one or
both directions. As shown, one of two retaining rings 38 may be provided, with
one of
the retaining rings having markings 40 or other indicia that allow a user to
position the
control cage 28 in a certain desired rotational orientation, so as to control
the direction of
the media being thrown by the blast wheel assembly 18.
As mentioned above, the media outlet 32 of the control cage 28 allows egress
of
blast media upon operation of the blast wheel assembly 18. In the illustrated
embodiment, the media outlet 32 is approximately rectangular in shape when
viewed
from the side (i.e., in a direction perpendicular to its axis) and is
approximately 3/5 the
height of the cylindrical wall 30 of the control cage 28. The size, shape, and
location of
the media outlet 32 may vary depending on the application, however. The length
of the
media outlet 32 is measured in degrees, from the innermost portion of the
opening
furthest ahead in the direction of rotation to the outermost edge of the
trailing portion.
While the media outlet 32 of the shown embodiment is approximately seventy
degrees
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for a wheel rotating in either direction, in other embodiments, the length of
the opening
(in either direction) may vary, depending numerous factors such as the overall
size of the
blast wheel assembly 18, the nature of the media being thrown, and the desired
rate of
flow, as would be understood by one of skill in the art.
Referring back to FIGS. 1-3, the wheel assembly 18, which is arranged
concentrically around control cage 28, includes the plurality of blades 26
sandwiched
between a rear wheel and a front wheel of the wheel 24 of the wheel assembly.
The
various parts of wheel assembly 18 are typically formed of cast iron, although
they may
also be made of any other appropriate material and/or method. The wheel
assembly 18 is
connected to the motor 20, in this embodiment by means of key inserted to lock
a shaft of
motor to the rear wheel of the wheel assembly, so that wheel assembly may be
rotated by
motor during operation of the blast wheel assembly. Blades 26, each of which
have a
heel end and a tip, are constructed and arranged to direct the blast media at
the surface
being treated. The blades 26 may be of any suitable size and any suitable
shape,
including one or more of straight, curved, flared, flat, concave, or convex
shapes.
The operation of the centrifugal blast wheel machine 10 is as follows. The
blast
media is fed from the feed spout 22 into the rotating impeller 14. By contact
with the
rotating impeller vanes (as well as with other particles of media already in
the impeller
14), the blast media particles are accelerated, giving rise to a centrifugal
force that moves
the particles in radial direction, away from the axis of the impeller. The
particles, now
moving in a generally circular direction as well as outwards, move through the
impeller
14 openings into the space between the impeller and the control cage 28, still
being
carried by the movement of the impeller vanes and the other particles.
When the particles that have passed though the impeller openings into the
space
between the impeller 14 and the control cage 28 to the media outlet 32, the
rotational and
centrifugal forces move the particles through the media outlet and onto the
heel ends of
the blades 26. The control cage 28 functions to meter a consistent and
appropriate
amount of blast media onto the blades 26. As the blades 26 of the blast wheel
24 rotate,
the particles are moved along their lengths and accelerate until they reach
the tips, at
which point they are thrown from the ends of the blades toward the work piece.
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Referring additionally to FIGS. 7-9, the locking ring 34 of the control cage
assembly 16 is secured to a peripheral edge of the cylindrical wall 30. As
shown, the
locking ring 34 is a separate element that is secured (e.g., by welding) to
the cylindrical
wall 30 of the control cage 28. The locking ring 34 includes an indicator
needle 42 that
projects radially outwardly from the locking ring. The indicator needle 42 can
be
integrally formed with the locking ring 34 or be secured to the locking ring
as a separate
component. The adaptor plate 36 includes a central opening 44 configured to
receive the
cylindrical wall 30 of the control cage 28 therein. The adaptor plate 36
further includes a
circumferential recess 46 that is sized and shaped to receive the locking ring
34 with the
control cage 28 being inserted into the locking ring and secured by the
retaining ring 38.
In one embodiment, the circumferential recess 46 is machined in the adaptor
plate 36.
The adaptor plate 36 further includes two recesses 48, 50 formed therein,
which
are configured to receive the indicator needle 42 when securing the locking
ring 34 and
the control cage 28 to the adaptor plate. Only one recess is accessible to
accept the
indicator needle 42, based on the wheel assembly 24. In one embodiment, the
wheel
assembly 24 is rotated clockwise with the indicator needle 42 in the recess 48
and a plug
52 placed in recess 50 to prevent accidental assembly. The plug 52 may be
machined or
cast, with an arrow embedded in the plug as an additional feature to show the
wheel
assembly 24 rotation. The plug 52 may be the same shape as the recess and
glued in
place with a suitable adhesive, such as LoctiteTM H4800. As shown, each recess
48, 50
extends outwardly from the circumferential recess 46 and is machined to a
depth co-
planar with the circumferential recess. Each recess 48, 50 includes a range of
movement
of the control cage 28 within the locking ring 34. In one embodiment, the
range of
movement is color coded so that the person installing the control cage
assembly 16 sets
the control cage 28 within an allowed set point range. Each recess 48, 50 is
designed to
provide a positive stop for the indicator needle 42 to prevent further
rotational movement
of the locking ring 34 and the control cage 28 beyond a recommended setting.
The
arrangement is such that the locking ring 34 freely floats between the
retaining ring and
the adaptor plate 36 until the retaining ring 38 is secured in place with
suitable fasteners,
e.g., machine screws.
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Referring to FIG. 10, the control cage 28 of embodiments of the control cage
assembly 16 of the present disclosure offers a "positive stop" that is placed
on the blast
wheel 24 by the adaptor plate 36 to prevent incorrect positioning of the
control cage. The
indicator needle 42 must be positioned within the recess 48 or 50 to properly
seat the
locking ring 34 within the circumferential recess 46 when inserting the
control cage 28 in
the central opening 44 of the adaptor plate 36. The control cage assembly 16
is
customized to the specific application and the location and the range of
movement of the
control cage 28 within the locking ring 34 will generally range from "9
o'clock" (270 ) to
"3 o'clock" (90 ) positions as viewed from the control cage retaining ring 38.
The
control cage assembly 16 is configured to provide an easy to read and
understand visual
reference to the current setting of the control cage/hot spot in relation to
the
manufacturers recommended set point. The assembly is designed to prevent the
accidental incorrect setting of the control cage/hot spot. (Incorrect control
cage settings
can adversely affect the hot spot and thus reduce the cleaning efficiency
ultimately
increasing cost. Additionally, incorrect control cage settings can direct the
hot spot
directly into the wheel housing itself causing damage and premature wear of
the wheel
unit.) The control cage assembly 16 is designed to prevent the incorrect
control cage set
point.
Having thus described several aspects of at least one embodiment of this
disclosure, it is to be appreciated various alterations, modifications, and
improvements
will readily occur to those skilled in the art. Such alterations,
modifications, and
improvements are intended to be part of this disclosure, and are intended to
be within the
spirit and scope of the disclosure. Accordingly, the foregoing description and
drawings
are by way of example only.
What is claimed is:
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