Note: Descriptions are shown in the official language in which they were submitted.
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PG-495
FLARED VAME FOR ABRASIVE BLASTING WHEEL
BACKGROUND OF THE INVENTION
The present invention relates to new and useful
improvements in abrasive blasting machines and in particular
to the abrasive throwing blades or vanes used in such
machines.
Abrasive blasting machines of the type having a wheel
or rotor assembly provided with a plurality of abrasive
throwing blades or vanes arranged radially about the face of
the rotor are well known. In use, a stream of abrasive
particulate material is fed into the path of the rotating
wheel from an impeller secured to the center of the rotor.
The vanes are adapted to receive and throw the abrasive from
the periphery of the rotor at an appropriate discharge point
in the machine casing at a blasting velocity to strip or
clean metal castings or the like.
The throwing vanes due to the nature of their use are
subject to excessive wear and are therefore removably
mounted on a runnerhead portion of the wheel assembly for
replacement as needed. In prior art devices the throwing
vanes have been provided with varying configurations for
improving the abrasive feed by increasing the length or
widening the vane for changing the blast pattern as for
example disclosed in U.S. Patents 3,242,615; 3,348,339 or
3,694,963. In other blasting machines the vanes have been
tapered or curved for providing minimum power consumption or
for noise reduction purposes such as disclosed in U.S.
Patents 1,196,885 and 3,872,624. In U.S. Patent 2,330,949
there is disclosed a rotatable abrasive spray head wherein
the vanes comprise open face channel members having a flared
configuration of 10 or more degrees for spraying the
abrasive therefrom.
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As is evidenced by these prior art patents a
considerable amount of effort has been expended in the past
in shaping the longitudinal blast pattern. However, very
little attention has been given to the transverse pattern of
the abrasive other than an effort to widen the pattern in
order to cover a wider surface when blasting lengthwise. It
has been found in these prior art vane configurations that
uneven distribution of the abrasive occurs transversely
across the width of the vane and has led to excessive wear
in certain areas on the face of the vane. In most vane
configurations the abrasive stream is contained by one
sidewall thereof where the abrasive accumulates after it
enters the heel area of the vane. The abrasive follows the
sidewall in a longitudinal discharge path causing excessive
wear in the face of the vane adjacent the sidewall along the
flow path as the accumulated abrasive follows the sidewall
to its discharge.
It is an object of the present invention to provide a
novel blasting wheel for an abrasive blasting machine.
Another object is to provide a throwing vane of novel
configuration for effectively reducing wear thereof during
use and prolonging the operating life of the vane.
A further object is to provide a vane for a blasting
wheel capable of effecting even distribution of abrasive
material across the face of the vane during operation of the
wheel.
It is still another object to obtain an even
distribution of abrasive transversely across the face of a
throwing vane surface at high horsepower and high abrasive
flow rates without increased costs.
SUMMARY OF T _ INVENTION
The present invention contemplates a vane for use in a
blasting wheel of an abrasive blasting machine. The vane is
provided with spaced longitudinally extending sidewalls
which flare away from the heel of the vane at an angle
preferably in the range of 2 to 7 degrees. Abrasive
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material fed to the heel during operation of the blasting
wheel spreads transversely of the vane at a controlled rate
of flow resulting in even distribution of abrasive along the
entire face of the vane.
The above and other objects and advantages of the
present invention will appear more fully hereinafter from
the detailed description which follows taken together with
the accompanying drawings wherein one embodiment of the
invention is illustrated.
DESCRIPTION OF THE DRAWINGS
In the Drawings:
FIG. 1 is a cross-sectional front elevational view of a
blasting wheel assembly having throwing vanes which
incorporate the present invention;
FIG. 2 is a sectional view taken on the line 2-2 of
FIG. 1; and
FIG. 3 is a perspective view of a throwing vane of
FIGS. 1 and 2 removed from the blasting wheel asse~bly.
DETAILED_DESCRIPTION
As illustrated in the drawings, a throwing wheel
assembly of an abrasive blasting machine is generally
indicated by the reference numeral 10 in FIGS. 1 and 2.
Assembly 10 includes a central hub or rotor 12 to which is
affixed a runnerhead 13 having a common axis therewith. A
plurality of curved vanes 14 are perpendicularly mounted on
the face 15 of runnerhead 13 and extend generally radially
from the axis of rotation of rotor 12. An innermost heel
portion 16 of each vane 14 is spaced a distance from the
axis of rotation for receiving particulate abrasive material
from an impeller means 18.
Impeller means 18 is disposed on the hub 12 between the
heel ends 16 of vanes 14 for feeding the abrasive particles
which are received from a fixed spout 20 to vanes 14 in a
usual manner. Impeller means 18 comprises an open ended
outer case 21 having flanges 22 connected to the machine
casing and open to the spout 20. An impeller 23 is disposed
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within case 21 and is rotatably affixed to hub 12. Impeller
23 is provided with openings 24 for discharging abrasive
received from spout 20 outwardly of case 21 through a
discharge opening 25 therein upon rotation of wheel 10. In
this manner abrasives are fed to the heels 16 of vanes 14 as
vanes 14 rotate past the opening 25. The abrasive is then
moved along the face 15 of the vane from the heel 16 to the
discharge end 17 for discharge therefrom at a selected
blasting velocity.
The face of runnerhead 13 has formed therein a
plurality of slots 26 which may be of suitable dovetail or
other undercut configuration at an angle to a radial line.
Each slot 26 is adapted to receive a base 27 of a curved
vane 14 with the base 27 being inserted into the slot 26 and
removable therefrom from the periphery of the runnerhead.
Once the base is inserted in a slot 26 it is retained
therein by a suitable locking pin Inot shown).
It is to be understood that the structure thus far
described refers to conventional structure as found in known
blasting wheel devices and that the present invention which
is to be hereinafter described in further detail is not
limited to the particular device shown. The drawings having
been simplified to show only conventional parts of wheel
assembly 10 as being necessary for a clear understanding of
the present invention.
As mentioned it is the feature object of the present
invention to provide a vane 14 of novel configuration for
increasing the wear characteristics thereof during use by
providing even distribution of the abrasive feed. To this
end spaced sidewalls 29 and 30 are provided for each vane
14. Sidewalls 29 and 30 are flared away from the center
line of face 15 of a vane 14 at an angle in the range of 2
to 7 degrees as designated "A" and "B" respectively in FIG.
2 from heel portion 16 to the discharge end portion 17 of
the vane.
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In testing of a blasting wheel having vanes 14 made
according to the present disclosure excellent wear
characteristics were achieved with containment of the
abrasive along one sidewall 29 or 30 substantially
eliminated. In these tests the abrasive entering a heel 16
of a vane 14 spreads evenly transversely of face 15
resulting in even surface wear and uniform abrasive
distribution.
In the mentioned tests utilizing a blasting wheel such
as blasting wheel assembly 10 having an 18 inch diameter was
used and operated at various RPM in the range of 1300 to
2500 RPM. For example, a test at a speed of 2200 RPM with
an abrasive flow velocity from the wheel of 250 FPS showed
no improvement or additional spread was effected at a flare
angle greater than 2-l/2 degrees. In a test at 1700 RPM and
an abrasive flow velocity from the wheel of 190 FPS no
spread occurred beyond a flare angle of 7. At 1300 RPM and
150 FPS no spread occurred beyond 10 or greater. It was
further found that no change in abrasive spread
characterlstics was effected by changing flow rates of the
abrasive from the impeller 18 to the vanes 14. It was
determined that the spread of abrasive was identical
regardless of the latter flow rates provided the flow was
within the capacity of the wheel assembly 10. It was
concluded that the spread is governed by the flare angle of
sidewalls 29 and 30, the RPM of the wheel assembly 10 and
the acceleration of the abrasive along the face of the vane.
Although one embodiment of the present invention has
been described in detail, it is to be expressly understood
that the invention is not limited thereto. Various changes
can be made in the design and arrangement of parts without
departing from the spirit and scope thereof as the same will
now be readily understood by those skilled in the art.
