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 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 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 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 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 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, 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 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. 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 Loctite™ 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. 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: