US3348339A - Abrasive blasting wheels and vanes - Google Patents

Description

Oct. 24, 1967 J. E. BOWLING, JR 3,348,339

ABRASIVE BLASTING WHEELS AND VANES Filed May 24, 1965 2 ShetsSheet 1 H'VVENTOR JOSfiplZlSiBOtUZiififm ATTORNEYS Oc 1967 J. E. BOWLING. JR

ABRASIVE BLASTING WHEELS AND VANES 2 Sheets-Sheet 2 Filed May 24, 1965 INVENTOR ATTORNEYS United States Patent g 3,348,339 ABRASIVE BLASTING WHEELS VANES Joseph E. Bowling, Jr., Waynesboro, Pa., assignor to The Pangborn Corporation, Hagerstown, Mi, a corporation of Delaware Filed May 24, 1965, Ser. No. 458,150 3 Claims. (Cl. 51-9) ABSTRACT OF THE DISCLOSURE A rotatable abrasive blasting wheel assembly includes a plurality of abrasive propelling vanes radially mounted on a rotatable wheel. The vanes alternately tilt forward and backward with respect to the wheel surface and include flared discharge ends so that the resulting blast pattern has a uniform distribution of abrasive particles over a substantially wider area than the width of each vane.

This application is a continuation-in-part of my application Ser. No. 400,527, filed Sept. 30, 1964, now abandoned.

This invention relates to an abrading apparatus and more particularly to an apparatus for widening the abrasive blast stream of abrasive blasting wheels.

In many abrasive operations it is desirable to use as wide and extensive an abrasive blasting pattern as possible. For instance, wide blasting patterns are most desirable when treating strip or sheet metal such as sheet steel. The use of wide blast patterns reduces the number of blast wheels required for such an operation.

One of the most serious problems encountered in blasting flat workpieces such as sheets and coils with present blasting methods is the problem of super-saturation of the blast stream at high, for example 100 horsepower, flows of abrasive. This problem is especially serious with the smaller sizes of abrasive, for example abrasive shot having an average particle size of 0.007 inch in diameter. Such small size abrasive is very desirable in for example descaling stainless steel because of the relatively light surface indentations it produces prior to cold reduction.

Super-saturation occurs, in essence, because the number of particles in the blast stream at a given time increases as the cube of the reduction in particle diameter while the space per particle in the stream area increases only as a square function of the diameter. When super-saturation occurs many of the particles are constrained from striking the workpiece and instead collide with each other thus reducing the blast efficiency proportionately.

Various means have heretofore been proposed for reducing the density of the blast stream. Some success for example has been attained by use of various configurations of openings in the impeller case of the abrasive blasting wheel which controls the manner in which the particles exude from the impeller area. This method however causes the density to be reduced by stretching the blast pattern longitudinally, and it is therefore limited to use with relatively wide workpieces since the most practical and economical way of blasting other than very narrow work is with the blast pattern normal to the direction of work travel. Mechanical and feeding limitations have made it impractical to reduce the density of the pattern of blast by merely widening the vanes and the feeding parts suchas the impeller and impeller case.

Another method which has been somewhat effective is that described in Patent No. 2,983,082. This method depends totally upon causing the abrasive particles to rebound out of the path of the incoming particles While actually concentrating the particles each wave thus 3,348,339 Patented Oct. 24, 1967 however tending to produce interference between particles in the same wave. This factor is increasingly important when blasting with very small particles. A further method is described in Patent No. 3,242,615, dated Mar. 29, 1966 in which means are described for Widening the blast stream.

It is therefore one objective of the present invention to provide a new and novel blast assembly wherein wider abrasive blast patterns are achieved than with former abrasive blast wheels.

Another object of the invention is to provide a new and novel rotatable blasting wheel assembly wherein the abrasive throwing vanes are flared at their discharge end with the vanes alternately tilted with respect to the surface of the blasting wheel.

Other objects and advantages of the invention will become more apparent from a study of the following description and drawings wherein:

FIG. 1 is a side view of the rotatable blast wheel assembly of the present invention;

FIG. 1a is a View similar to FIG. 1 in a different phase of operation;

FIG. 1b schematically shows the total effect of the blast streams shown in FIGS. 1 and 1a;

FIG. 2 is a plan view of a portion of the rotatable blast wheel assembly shown in FIG. 1;

FIG. 3 is a side elevation of a backwardly tilted vane or blade used in the assembly of FIGS. 1-2;

FIG. 4 is a top view of the blade shown in FIG. 3;

FIG. 5 is an end view of the blade shown in FIGS. 3-4;

FIG. 6 is a bottom view of the blade shown in FIGS. 3-5;

FIG. 7 is a side elevation of a forwardly tilted vane or blade used in the assembly of FIGS. 1-2;

FIG. 8 is a top view of the blade shown in FIG. 7; and

FIG. 9 is an end view of the blade shown in FIGS. 7-8.

This invention overcomes the limitations of prior devices as described above by spreading the blast pattern in width rather than in length without at the same time changing the width of the feeding elements. This is accomplished by having the vanes canted or tilted alternately forward and backward, and at the same time by flaring the outer or discharge ends of the vanes in the direction of particle flow. This method causes the alternate particle -waves to strike the workpiece in a side-by-side attitude from the stream; the present device effectively uses lesser volume and lesser horsepower.

It has been demonstrated by tests that the present method of applying the blast allows eflicient use of 40% greater abrasive particle flows. For example, tests run on stainless steel coils with very small abrasive particles (0.007

inch in diameter) showed that, whereas with conventional blasting methods super-saturation and ineflicient blasting occurred at 6870 H.P. abrasive loading, the method of this invention allowed eflicient blasting i.e.

. proportionate increase in work travel, up through a flow of HP. This means that where it formerly would require, for example twelve blasting units on the blast machine to meet production requirements, it is now pos- 3 sible to build the blast machine with only eight blast units with a consequent reduction in capital investment of about one-third. Accordingly, whereas supersaturation has a detrimental effect on prior arrangements at about 68 HR, it is eliminated as a problem with the present arrangement even at 100 HP.

Referring now to the drawing a rotatable blast wheel assembly is shown in FIGS. 1 and 2 which includes a blast wheel 1 having vane supporting channels 3 for supporting alternately tilted or canted vanes 5 and 7. The vanes 5 and 7 are held in channels 3 by, for example, suitable locking pins 9 which fit into the channels 3 and the cutouts 11 in the dovetail base 13 of the vanes 5 and 7. Channels 3 are for example 2 /4 inches wide at their widest point to receive vanes 5 and 7 which are slightly less than 2% inches wide at their widest point.

An indent 14 (see FIGS. 3 and 7) in the base 13 of the vane houses a pressure spring which rests on the floor of the vane channel 3. The spring (not shown) urges the blades or vanes 5 and 7 upwardly to give a good tight fit of the base walls of the vane against the channel walls in the wheel 1.

Vanes 5 and 7 are fed abrasive particles which are introduced into spout 30 into impeller cage 32 and through slot 34 in the impeller cage.

The abrasive propelling face 15 of the backwardly inclined vane 7 is best shown in FIG. 3. A strengthening rib 17 is formed at the end of the face 15 of the vane. This provides reinforced strength for the vane during its rotation and operation. The vane has an outer extending edge or flange 19 at the upper edge thereof by which an open trough or channel is formed with the face 15 along which the abrasive flows. As clearly shown in FIG. 3 the discharge or outer end of each vane 7 is flared by inclining the upper edge 19 outwardly away from the surface of wheel 1.

FIG. 4 is a top view of vane 7 having its face 15 tilted away the direction of rotation of the wheel 1. In other words vane 7 has a negative slant with its discharge face 15 being inclined at an obtuse angle of, for example, about 6 with respect to the outer surface of wheel 1. The inclination is best shown in FIG. 5 which indicates the degree of slant of discharge face 15 by reference to the center line 27 of vane 7 which is perpendicular to the outer surface of wheel 1.

FIG. 7 best shows abrasive propelling face 16 of the forwardly inclined vane or blade 5. A strengthening rib 17 and an upper flange are also provided on vane 5. Unlike vane 7, the upper flange 2.0 of vane 5 is parallel to the surface of throwing wheel 1. The lower edge 22, however, is inclined toward throwing wheel 1 thus causing the discharge end of vane 5 to be flared.

FIGS. 8 and 9 similarly show vane 5 which slants toward the direction of rotation of wheel 1 or in other words has a positive slant with its discharge face 16 being inclined at an acute angle, of for example, about 6 with respect to the outer surface of wheel 1. The extent of slant is also indicated in FIG. 9 by reference to the center line 27.

FIG. 1 illustrates the resultant "blasting pattern with alternately canted vanes 5 and 7, each having oppositely flared discharge ends. As shown in FIG. 1 the workpiece 21, for example, a stainless steel coil, travels from right to left. The resultant widened blasting pattern is clearly apparent from FIGS. 1, la and 1b. As shown in FIG. 1a, stream S, of the forward canted vanes 5 moves along lowered flared edge 22, strikes work piece 20, and ricochets away from the line of travel of the incoming waves. Correspondingly as shown in FIG. 1, stream s from the backward canted vanes 7 moves along upper flared edge 19 and also richochets away from the line of an incoming wave after striking work piece 20. Thus the blasting pat: tern width is greatly increased, as shown in FIG. 112, over the blasting pattern of a conventional blasting assembly while at the same time, drastically reducing the stream density.

The feed elements for the tilted vanes are most clearly shown in FIG. 1. As indicated therein abrasive particles. are fed into spout 30 to the impeller which includes irripeller vanes 34 and impeller cage 36 having a slot 35. The width of the abrasive flow path is, of course, the width of slot 35. With the aforedescribed arrangement it is only necessary for the extreme end of the tilted vanes to be flared to clear the abrasive flow path. Accordingly, flared edge 22 of forwardly canted vane 5 is substantially in line with one end of slot 35, while flared edge 19 of backwardly inclined vane 7 is substantially in line with the other end of slot 35. As clearly indicated in FIG. 1b the combined blasting elfect from vanes 5 and 7 is a widened symmetrical pattern.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A rotatable abrasive blasting wheel assembly comprising a rotatable wheel, said wheel having a surface perpendicular to the axis of rotation of said wheel, abrasive propelling vanes secured to said wheel, each of said vanes having a lower edge disposed against said wheel, said lower edge being parallel to said surface from its inner edge near the center of said wheel to the periphery of said wheel, each of said vanes having a planar abrasive propelling face with a feed end near the center of said wheel and a discharge end near the periphery of said wheel, said discharge end of each face being flared outwardly relative to said surface and with respect to said feed end, the abrasive propelling face of every other vane being forwardly inclined at an acute angle with respect to said surface, and the abrasive propelling face of the intervening vanes being backwardly inclined at an obtuse angle with respect to said surface.

2. An abrasive propelling vane for use in rotatable blasting wheel assemblies, said vane comprising a base support with a planar supporting surface, a feed end, a discharge end, a planar abrasive propel-ling face between said feed end and said discharge end, a first flange on said abrasive propelling face remote from said surface, a second flange on said abrasive propelling face adjacent said surface, said second flange being parallel to said surface, said first flange terminating at the discharge end in a flared portion which is inclined toward said surface, and said abrasive propelling face being tilted forward out of perpendicular alignment with said surface.

3. An abrasive propelling vane for use in rotatable blasting wheel assemblies said v-ane comprising a base support with a planar supporting surface, a feed end, a discharge end, a planar abrasive propelling face between said feed end and said discharge end, a first flange on said abrasive propelling face remote from said surface, a second flange on said abrasive propelling face adjacent said surface, said second flange being parallel to said surface, said first flange terminating at the discharge end in a flared portion which is inclined away from said surface, and said abrasive propelling face being tilted backward out of perpendicular alignment with'said surface.

References Cited UNITED STATES PATENTS 469,642 2/1892 Nehr 519 2,077,637 4/1937 Minich 519 2,314,069 3 1943 Blount 51-9 2,983,082 5/1961 Gossard 51--9 3,242,615 3/ 1966 Physioc 5 l9 LESTER M. SWINGLE, Primary Examiner.

Claims (1)

1. A ROTATABLE ABRASIVE BLASTING WHEEL ASSEMBLY COMPRISING IN A ROTATABLE WHEEL, SAID WHEEL HAVING A SURFACE PERPENDICULAR TO THE AXIS OF ROTATION OF SAID WHEEL, ABRASIVE PROPELLING VANES SECURED TO SAID WHEEL, EACH OF SAID VANES HAVING A LOWER EDGE DISPOSED AGAINST SAID WHEEL, SAID LOWER EDGE BEING PARALLEL TO SAID SURFACE FROM ITS INNER EDGE NEAR THE CENTER OF SAID WHEEL TO THE PERIPHERY OF SAID WHEEL, EACH OF SAID VANES HAVING A PLANAR ABRASIVE PROPELLING FACE WITH A FEED END NEAR THE CENTER OF SAID WHEEL AND A DISCHARGE END NEAR THE PERIPHERY OF SAID WHEEL, SAID DISCHARGE END OF EACH FACE BEING FLARED OUTWARDLY RELATIVE TO SAID SURFACE AND WITH RESPECT TO SAID FEED END, THE ABRASIVE PROPELLING FACE OF EVERY OTHER VANE BEING FORWARDLY INCLINED AT AN ACUTE ANGLE WITH RESPECT TO SAID SURFACE, AND THE ABRASIVE PROPELLING FACE OF THE INTERVENING VANES BEING BACKWARDLY INCLINED AT AN OBTUSE ANGLE WITH RESPECT TO SAID SURFACE.

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