US2344989A - Abrading apparatus - Google Patents

Description

March 28, 1944. w. 1.. KEEFER ABRADING APPARATUS Filed Aug. 24, 1942 2 Sheets-Sheet 1 Patented Mar. 28, 1944 U N IT E D STAT E FA? E T OFFICE RADING APPARATUS Application August 24, 1942, Serial No. 455,323

6 Claims.

The present invention relates to abrading apparatus of the type for centrifugally propelling or throwing abrasive particles at abrading or blasting velocities and more specifically pertains to means for transferring abrasive from a supply source to a position to be engaged by the propeller blades of such apparatus at a predetermined point or zone in the rotation thereof.

An object of the invention is to provide a centrifugal abrasive propelling wheel wherein directional control is obtained without the use of a control cage surrounding an impeller within which the abrasive is whirled and later discharged through an opening in the peripheral wall of the cage.

Another object of the invention resides in providing means for efiiciently transferring abrasive particles from a plurality of rotating impeller vanes directly onto the rotating propeller blades of the apparatus so as to obtain directional control of the abrasive discharged by the propeller blades.

A further object of the invention resides in providing an annular space between the path described by the inner ends of the propeller blades and the path described by the outer periphery of the impeller vanes including means for feeding abrasive into such annular space and means for preventing the abrasive particles from bounding rearwardly and circumferentially over the periphery of the rotating impeller.

Another object of the invention pertains to the provision of means for controlling the admission of a current of air to the axis of the impeller including means for directing such a cur rent of air radially outward through spaces between the impeller vanes whereby the radial outward current of air assists in the fiow of abrasive and moves any stray abrasive particles so as to merge such stray particles with the main stream discharged from the impeller.

Other objects and features of the invention will be more apparent to those skilled in the art as the present disclosure proceeds and upon consideration of the accompanying drawings and the following description, wherein an exemplary embodiment of the invention is disclosed.

In the drawings:

Fig. 1 is an end elevational view of the abrading apparatus illustrating the manner in which the outer or free end of the wheel is closed for controlling the entrance of air to the center of the impeller.

Fig. 2 is a sectional view of the abrading apparatus taken on the line 2- -2 of Fig. 1.

Fig. 3 is a sectional view of the impeller and a portion of the rotor taken on the line 3 -3 of Fig. 2.

Fig. 4 is a sectional view of a portion of the holder for'the feed spout and taken on the line 4-4 of Fig. 1.

Fig. 5 is a sectional plan view of a portion of the feed spout holder when in the dotted line. position 5 of Fig. 1 showing a bafile arrangement to provide an underhand horizontal blast from the periphery of the wheel.

Fig. 6 is a sectional View of the baffle, and an end of the feed spout taken on the line 6-6 of Fig. 5.

Fig. 7 is a sectional plan view of a portion of a feed spout and baflle for use in the position indicated by the dotted. line 7 of Fig. 1 or when an overhand horizontal blast is desired.

Fig. 8 is a sectional view of the baille taken on the line 88 of Fig. '7.

Referrin to the drawings, and particularly to Fig. 2, there is shown at R a rotor assembly which may be of a conventional type comprising a disc or runner head l5 securely mounted on a shaft It to rotate therewith and a plurality of abrasive propelling blades 2! which may be removably secured to the disc or runner head 55 in any suitable Or conventional manner. The propeller blades 2| may, for example, be provided with wedge shaped inner edges 22 mounted within dovetailed grooves in or on the runner head I5. The propeller blades 2! may also be retained in the dovetailed grooves in any suitable manner (not shown). Each propeller blade is provided with an upstanding flange 26 along its outer or free edge'and on the forward face of each blade for the purposes of preventing abrasive particles from spilling over the outer edges of the propeller blades. The inner ends of the propeller blades 2| terminate short of the axis of the rotor and taper or flare outwardly as indicated at 28 in Fig, 2. Th inner ends of the propeller blades may also be beveled as illustrated in Fig. 3 to more efficiently intercept the abrasivesupplied. to the inner ends of these throwing blades.

The. invention includes means for transferring abrasive'from a feed spout to a position to be engaged by the propeller blades 2| at one point or zone in the rotation thereof and such means may take the. form of a hollow impeller T mounted between the inner ends. of the propeller blades 2i and adapted to rotate with the rotor R. For this purpose the impeller may be rigidly secured to the disc or runner head l5 by means of a bolt 32 passing through an opening in a boss on the impeller and into threaded engagement with the hub H of the rotor. The general overall shape of the impeller may be regarded as frustro-conical in that a series of impeller vanes 36 converge inwardly toward each other at the outer or free end of the impeller so that the periphery thereof outlines a frustro-conical shaped assembly. The outer or free ends of the impeller vanes 36 may be suitably joined such as by means of an end ring 38 which may be formed integral with the impeller vanes. The rear portion of the impeller is preferably closed by means of a radial Wall 39. The impeller vanes 35 are each provided with a ledge 4| which extends forwardly of each impeller vane 36 with regard to the direction of rotation of the impeller and the rotor. The ledges or extensions 4| preferably project from the impeller vanes from points spaced radially inwardly from the outer peripheral edge of each impeller vane. The extensions or ledges 4| also follow the frustro-conical shape of the impeller vanes 36. It is to be noted that the extensions or ledges 4| do not close the peripheral portion of the impeller but terminate short of each forward impeller vane so as to provide a radial opening or aperture 46 between each pair of impeller vanes for the purpose to be hereinafter described.

The outer face or free end of the rotor assembly R is covered so as to prevent splattering of abrasive particles and for the further purpose of preventing uncontrolled access of air to the propeller blades and to the impeller. The closure means may take the form of a housing indicated at H in Figs. 1 and 2 provided with suitable removable wear plates 5| and a disc member or feed spout holder shown generally at 52 in Figs. 1 and 2. The feed spout holder or disc member 52 is preferably mounted within an opening in the housing H and the wear plate or plates 5| and for this purpose the disc like member 52 is provided with an annular flange 53 to facilitate the mounting thereof and adjustment of the feed spout holder circumferentially within the opening in the housing, The disc member 52 which also serves as part of the closure means may be adjustably secured within the opening in the housing by means of clamps 55 shown more clearly in Fig. 1.

The apparatus includes means for feeding or supplying abrasive particles over the outer periphery of the impeller vanes 36 and such means may take the form of a feed spout shown at 6| in Figs. 1 and 2 wherein the feed spout and the position thereof is designed and arranged for providing a down blast discharge from the periphery of the rotor R. The feed spout 6| may extend through an opening 62 in the disc member 52 so as to discharge abrasive in a downward direction represented approximately by the arrow 60 in Fig. 2 and in a generally axial direction onto the impeller vanes 36. The feed spout may be provided with a cylindrical member 63 which is adapted to be seated within the opening 62 in the disc member 52 and thus close this opening around the feed spout. The cylindrical member 63 also permits relatively minorangular adjustments of the feed spout 6|. The feed spout 5| preferably terminates on the dotted line 66 as shown in Fig. 2. The abrasive particles in leaving the feed spout continue to follow the contour of the spout and thus pass to a position to be engaged by the forward faces of the impeller vanes 36. This arrangement provides that most of the abrasive will rest against the impeller vanes 35 with enough contact that centrifugal force will be developed for causing the abrasive to turn and move radially outward on the impeller vanes 36. It may be possible that some of the abrasive would normally fall between the impeller vanes 36 unless prevented and it is for the purpose of preventing such extreme radial inward movement of th abrasive that the ledges 4| are provided. Any abrasive that may strike or engage the ledges 4| will move rearwardly thereon or ricochet slightly upward so as to be engaged by the radial forward faces of the impeller vanes 36 and be discharged therefrom by centrifugal force.

In order to prevent any rearward bounding of the abrasive that may first engage the peripheral edges of the impeller vanes 36, stationary means such as a baffle member 68 i provided within the annular space between the impeller and the inner ends of the propeller blades and positioned adjacent and immediately rearwardly of the feed spout 6|. All of the abrasive passing from the feed spout 5| should normally be fed forwardly by the impeller, but a few grains striking the peripheral edges of the impeller vanes 3-6 may bound away rearwardly. The stationary baflie member 68 extending within the annular opening intercepts any rearwardly bounding abrasive particles. The baffle 68 may be supported or carried by the feed spout and may be formed as an extension of the feed spout 6| as shown in Fig. 4. The radial dimensions of the bafiie 68 corresponds substantially to the radial width of the annular space around the impeller.

The invention includes additional means for preventing splash of the abrasive, and such means may take the form of a relatively flat ring member arranged around the impeller and cut away adjacent the feed spout 6| as shown in Fig. 4. The ring member H is preferably removable so as to be replaced when worn, and may be secured to the disc member 52 in any suitable manner such as by means of a plurality of screws 12. The ring member II is of such thickness as to guide the abrasive onto the inner ends of the propeller blades 2| inside the flanges 26. The ring member substantially closes the outer end of the annular space and prevents the escape of abrasive,

The invention further embraces the provision of means for directing a current of air through the impeller vanes to assist in the flow of abrasive. Thus the central portion of the means closing the outer end of the abrading apparatus is provided with a passage or opening 8| communicating with the interior of the impeller. The fan action of the propeller blades 2| and the impeller vanes 35 thus develops an air current which is drawn through the passage or opening 8| into the center of the impeller T. An arcuate shaped guard member extends within the hollow impeller and this guard may be formed as an integral part of the disc member 52. The guard 82 is so-dimensioned as to prevent the air current from entering all of the spaces 45 between the impeller vanes and thereby causes the air current to be concentrated in a few of such spaces so that a rapid rush of air radially outwardly through the spaces adjacent the feed spout assists in the flow of.abrasive and lifts stray abrasive particles and merges them with the main stream of abrasive leaving the impeller.

In the operation of the abrading apparatus the shaft I is driven by suitable means and at a speed sufiicient to impart abrading or blasting velocities to the abrasive carried by the propelling blades. The abrasive is supplied to the feed spout 6| preferably in metered or regulated quantities n t s particles pass in the general direction of the arrow 69 in Fig. 2 towards the periphery of the frustro-conical shaped impeller T. The impeller rotating with the rotor R causes the forward faces of the impeller vanes 36 to engage such abrasive particles. Thus most of the abrasive will engage the impeller vanes 36 with enough contact so that centrifugal force will be developed by the rotating impeller whereby the abrasive will turn quite quickly and move outwardly on the forward faces of the impeller vanes. If the particles are supplied to the impeller at approximately the twelve oclock position, as shown in Figs. 1 and 2 the main stream of the abrasive particles will leave the impeller vanes in a generally tangential manner at about the ten thirty oclock position. The first abrasive particles may leave the impeller at about the eleven oclock position with the last particles leaving the impeller at about the ten oclock position.

It may be possible that some of the abrasive will not be immediately engaged by the forward faces of the impeller vanes 36 and these particles may, unless prevented, fall between the impeller vanes. The ledges ll prevent such particles from moving towards the axis of the impeller and the particles engaging the extensions M are then acted upon centrifugally by the impeller vanes 36. Thus these particles are thrown from the impeller and merge with the main abrasive discharge.

The bafile 63 prevents any of the abrasive particles from bounding rearwardly with respect to the direction of rotation and any of the abrasive particles tending to fall through the spaces 46 will be returned to the main stream by the air currents flowing in the direction of the radial arrows shown in Fig. 3. The ring member ll also guides the abrasive onto the channel shaped propelling blades 2| inside the flanges 26. The abrasive stream is thus projected into the path swept by the propelling blades 2| so that each blade cuts off a portion of the stream of abrasive. The abrasive remains on the propelling blades during movement of these blades through an arc of approximately 90 before being discharged therefrom if the blades are of the radial type. The arrangement shown in Figs. 1, 2 and 3 thus provides a downblast discharge from the peripnery of the wheel or rotor R.

If it is desired to obtain an underhand horizontal blast, the feed spout 6i and the bafiie 68 are removed from an operative position on the wheel and the disc member 52 is then rotated so as to position the opening 62 for the feed spout at the dotted line position indicated at 5 in Fig. 1, or at approximately the nine oclock clockdial position. The feed spout 6! is then replaced by one having an inner end arrangement such as shown in Fig. 5. This feed spout 6 la is also provided with a cylindrical member 63a for mounting within the opening 62 in the disc member 52. The feed spout 61a preferably converges towards the impeller as shown in Fig. 5 so as to direct the abrasive towards the impeller vanes 36. The feed spout SM is also provided with a baffle 68a of triangular shape in radial dimensions and arranged rearwardly of the point where the abrasive is supplied to the impeller, or on top of the abrasive stream. The abrasive is thus unsupported by the spout after it leaves the lip 9| but a side wall portion 92 of the feed spout assists in guiding the abrasive towards the impeller.

The abrading apparatus is universal in application and if an overhand horizontal blast is desired from a periphery of the wheel a feed spout such as shown in Figs. '7 and 8 is employed. The opening 62 for the feed spout is then positioned at the approximate three oclock position by rotation of the disc member 52. A feed spout 6|b is then employed designed to direct the abrasive towards the impeller vanes 36 as shown in Fig. 7. The feed spout 6lb is provided with a cylindrical member 63?; for mounting within the opening 62 in the disc member 52. This type of feed spout also includes a baflie 68!) positioned under the feed spout and providing an extension of the lower wall thereof. The baflle 68b is preferably inclined so as to assist in directing the abrasive towards the impeller vanes as shown in Fig. 8.

When it is desired to obtain an up-blast from the wheel the abrasive is supplied at about the six oclock position. In this case most of the abrasive will enter the spaces between the propelling blades 2| directly by gravity and the impeller vanes 35 will then serve to deflect any stray abrasive into the path of the propelling blades 2|, Thus, in all of the four positions of the discharge all parts of the wheel remain the same, except for the feed spout and the baffle members which extend into the annular triangular space between the impeller and the path described by the inner ends of the propelling blades. Adjustments of the discharge may of course be made by small circumferential changes inthe position of the disc member 52 and such adjustment is made possible by means of the clamps 56. The abrading apparatus thus provides the advantage that the transfer mechanism consists merely of one part or the impeller.

Thus the wheel lacks any control cage or container having a peripheral opening therein which is readily worn and which destroys some of the abrasive as it is whirled within the cages. The abrading apparatus also provides the advantage of being relatively simple and permits convenient replacement of the various parts.

While the invention has been described with reference to specific structural details, it will be appreciated that changes may be made therein by those skilled in the art. Such modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. In abrading apparatus, a rotor including a plurality of propeller blades extending inwardly short of the axis of the rotor, an impeller mounted between inner ends of said propeller blades rotating with said rotor, a plurality of circumferentially spaced vanes carried by the impeller, a circumferentially extending ledge carried by each vane terminating short of an adjacent vane, means for feeding abrasiv over the peripheral edges of said vanes, stationary means substantially closing the free end of said impeller and said. rotor, said closure means having an opening therethrough at the axis of the rotor whereby a current of air is drawn through said opening by the rotating propeller blades and the rotating impeller vanes, and means within the impeller for confining the radial outward movement of the air currents through spaces between the impeller vanes adjacent the point where the abrasive is supplied to the impeller.

2. In abrading apparatus, a rotor including a plurality of propelling blades extending inwardly short of the axis of the rotor and tapering outwardly at the inner ends thereof, an impeller mounted between the inner ends of said propeller blades rotating with the rotor, a plurality of circumierentially spaced vanes carried by the impeller outlining a frusto-conical shaped periphery and providing a triangular shaped annular space between a path described by the inner ends of the propeller blades and a path described by the outer ends of the impeller vanes, a ledge carried by each impeller vane at a point inwardly from the periphery of the impeller vanes without closing the spaces between the impeller vanes, a disc shaped member at the free end of the impeller, a feed spout extending through said disc member for delivering abrasive into said triangular space and onto the periphery of said impeller, a triangular shaped baffle carried by the feed spout extending into said triangular space, said disc member having an opening therethrough at the axis of the impeller, and a guard member carried by the disc member extending axially within said impeller so as to prevent radial movement of air currents outwardly through spaces between the impeller vanes except at points adjacent the place where abrasive is supplied to the impeller.

3. In abrading apparatus, a rotor including a plurality of propelling blades extending inwardly short of the axis of the rotor and tapering outwardly at the inner ends thereof, an impeller mounted between the inner ends of said propeller blades rotating with the rotor, a plurality of circumferentially spaced vanes carried by the impeller outlining a frusto-conical shaped periphery and providing a triangular shaped annular space between a path described by the inner ends of the propeller blades and a path described by the outer ends of the impeller vanes, a circumferentially extending ledge carried by each inpeller vane, a disc shaped member at the free end of the impeller, a feed spout extending through said disc member for delivering abrasive into said triangular space onto the periphery of said impeller, and a ring member carried by said disc substantially closing th outer free end of said triangular shaped annular space.

4. In abrading apparatus, a rotor including a plurality of propeller blades extending inwardly short of the axis of the rotor and tapering out- Wardly at the inner ends thereof, an impeller mounted between the inner ends of said propeller blades rotating with said rotor, a plurality of circumferentially spaced vanes carried by the impeller outlining a frusto-conical shaped periphery and providing a triangular shaped annular space between a path described by the inner ends of the propeller blades and a path described by the outer ends of the impeller vanes, a feed spout for delivering abrasive into said triangular shaped space in a direction generally axially of the impeller, a triangular shaped baflie extending into said triangular shaped space forming a continuation of the rear wall of the feed spout with regard to the direction of rotation, and a wall member on said bafile for guiding the abrasive towards the periphery of the impeller.

5. In abrading apparatus, a rotor including a plurality of propeller blades extending inwardly short of the axis of the rotor and tapering outwardly at the inner ends thereof, an impeller mounted between the inner ends of said propeller blades rotating with said rotor, a plurality of circumferentially spaced vanes carried by the impeller outlining a frusto-conical shaped periphery and providing a triangular shaped annular space between a path described by the inner ends of the propeller blades and a path described by the outer ends of the impeller vanes, a feed spout for delivering abrasive into said triangular shaped space, and a triangular shaped bafiie carried by the feed spout extending into said triangular shaped space and inciined with respect to the horizontal for directing the abrasive towards the periphery of said impeller and preventing the abrasive from bounding rearwardly over the impeller vanes with respect to the direction of rotation thereof.

6. In abrading apparatus, a rotor including a plurality of propeller blades extending inwardly short of the axis of the rotor and terminating in tapered inner ends, a rotatable impeller mounted between the inner ends of said propeller blades including circumferentially spaced vanes outlining a frustuin of a, cone and providing an annular space triangular shaped in radial dimensions between a path described by the inner ends of the propeller blades and a path described by the outer ends of saidimpeller vanes, a circumferentially extending ledge carried by each impeller vane terminating short of an adjacent impeller vane, a downwardly extending feed spout curved towards said annular space and terminating adjacent the outer end of said impeller for supplying abrasive in a generally axial direction into said triangular shaped space and over the outer peripheral ends of said impeller vanes, and a plate-like bafiie member triangular shaped in radial dimensions carried by the feed spout and forming a continuation of a rear wall portion thereof with respect to the direction of rotation and extending into said triangular space for preventing abrasive particles from bounding rearwardly over the outer peripheral ends of said impeller vanes.

WALTER L. KEEFER.

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