Note: Descriptions are shown in the official language in which they were submitted.
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Cylindrical open meshwork rolls are known to the art and have
gained wide acceptance in a large number of heavy duty applications where
high structural strength is required, while maximizing flow of fluid through
the structure. Gne use for such rolls is in making cylindrical suction rolls
and other types of filter support media. In one type of open meshwork roll,
to which this improvement applies, th~ roll is a unitary hollow cylindrical
honeycomb open work formed of alternate straight and undulating thin strips
of metal extending axially from one end support to the other. The circular
end supports of the rolls haue radial slats to receive and support the ter-
minal end pieces of the axial~y extending strips. A more detailed descript-
ion of this form of roll construction may be found in my U.S. Patent
3,139,375 showing the bonded end pieces and radial slots, and in my U.S.
Patent 3,590,453 showing the three-part bonded end pieces.
The fabricating procedure used in the prior art to attach the
terminal ends of the strips in the slots of the circular end members was to
individually and successively braze each strip end piece set into its receiv-
ing slot. This procedure was very time consuming in terms of the man hours
required to braze each joint separately. In addition, the heating of each `
joint was not uniformly controlled and consequently there was no assurance
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that the brazing of each joint was uniform; indeed because of different tech-
niques used by different workmen and the fatiguing nature of the repetitive
work, quality of the brazed work varied substantially.
The tolera~ces of the bonded end pieces were not closely controlled -
in the prior art. For example, metal strips of 0.050 inches stock, manu~
factured to mill tolerance, could vary by - 0.005 inches in thickness.
Therefore, an end piece of three such strips could vary by 0.030 inches.
The 0.030 inches variation in end piece thickness requires that each joint
between the end rolls and end pieces receive a varying amount of brazing
material and be heated separately. In addition, in order to be sure that
the brazing mater~al did not fl~w out of the joint after brazing, it was
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necessary to be sure that the joint had cooled off before the slot was
moved from an upright vertical position.
Thus, it was desirable to provide an improved process for obtain-
ing high quality and uniform brazed connections between the strips which
form the honeycombed open work and the circular end members which support
the open work.
According to the present invention there is provided in a method
for making open meshwork rolls of the type formed of a pair of circular end
members, each having radial slots of uniform dimensions spaced around the
inner faces and outer periphery thereof, said slots having openings on the
inner faces of said end members and being open to the periphery of the end
members, and an open meshwork made rom alternate strips of straight and
corrugated thin metal, adjacent strips being bonded together to form integral
end pieces fitting into the slots in the end members, the improvement com-
prising the steps of: bonding the end pieces by swaging them to closely con-
trolled tolerances and inserting them into said slot openings of said slots -~
in said inner faces to form an open meshwork roll with an axis of rotation;
encircling each end member with a strip of brazing alloy, at least partially
overlapping said slots the strip being in close proximity to the said slot
openings in which the end pieces are inserted; slowly rotating said roll on
said axis while applying heat evenly to each end member, thereby melting the
strip of brazing alloy and causing it to be free flowing; flowing the free- -~
flowing brazing material into the peripheral openings of said slots in the
end members, whereby brazing the end members to the end pieces when the
brazing material has solidified.
In this application and the aocompanying drawings, there is shown
and described a preferred embodiment of the invention and suggested various
alternatives and modifications thereof, but it is to be understood that these
are not intended to be exhaustive and that other changes and modifications
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can be made within the scope o~ the invention. These suggestions are se-
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lected and included for pu~poses of illustration in order that othersskilled
in the art will more fully understand the invention and the principles
thereof, and will be able to modify it in a variety of forms, each as may
be best suited in the condition of a particular case.
IN THE DRAWINGS
Figure 1 is a cut-away pe~spective view of the roll.
FiguTe 2A is a cross-sectional detailed view of the end members
with the brazing strip applied.
Figure 2B is a cross-sectional detailed view of the end members
after the brazing material has been melted.
Figure 3 is a detailed view of one arrangement of the end members
and strips.
Figure 4 is a detailed view of another arrangement of the end mem-
bers and strips. ;
Figure 5 is a cut-away schematic view of the brazing operation.
Figure 1 shows generally a typical construction for an open mesh-
work cylindrical roll 12 of the type which could be made by this improved
process. Metal strips 14 are shown as being either straight, as at 16, or
corrugated, as at 18, and lying axially along the length of roll 12. Adja-
cent strips are bonded together at intervals, as at 20, and the ends of sets
of adjacent strips are bonded together to form end pieces 22. The end pieces ~-
fit into radial slots 24 which are located around the periphery of circular
end members ?6 and 27. After roll 12 has been assembled, as shown in Figure
1, a strip of brazing material 36 ~shown in Figure 2A) is applied to the
periphery of end members 26 and 27 to encircle the same. Also shown in -
Figure 2A are end pieces 22 in radial slots 24.
For further clarity, Figure 3 shows a detailed view of the strips
14, end pieces 22, and slots 24 into which the end pieces 22 fit. In this
embodiment, the end pieces 22 are swaged to a tolerance of - .002 inches
and the slots 24 are a minimum of .022 inches larger than the largest thick- -
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ness of the end pieces 22. As a result, for a minimum end piece thickness,
the slot will allow at least .004 inches clearance. For maximum strength,
the gap 28 to be filled by brazing material should be between .000 inches and
.010 inches. It can be seen that the limit achieved by ~his embodiment is
within that optimum range. The close clearance maintained between the slots
24 and the swaged end pieces 22 is important for reasons which will be des-
cribed hereafter.
Figure 4 is a detailed view similar to Figure 3 except that it
shows a slightly different embodiment for an open meshwork structure 30 which -~`
results in additional end-pieces 46 and s,ots 32 in end members 31.
Figure 5 shows the entire roll 12 placed in oven 34. However, any
suitable means for uniformly heating the end members 26 and 27 may be used. ~;
A strip of brazing material 36 is shown completely encircling end members ~ ;
26 and 27 at the joints, as at 38, between the end pieces 22 and the end -
members 26 and 27. The end members 26 and 27 and strips of brazing material
36 are heated to a temperature at which the brazing material 36 melts and
may flow freely. In one embodiment of this process the brazing material ;~-
employs a silver or nickel base alloy which flows readily at 1600 to
2200F. `
The heated roll 12 is slowly rotated by motor 40 and drive assembly
42 to ensure that each end member 26 and 27 is heated uniformly. As shown
in Figure 2B the free flowing brazing material 44 of strips 36 is drawn by
capillary action into the gap 28 between the swaged end pieces 22 and the
walls 48 of the slots 24. The gaps 28 between the slots 24 and swaged end ~-
pieces 22 must be sufficiently small to maintain capillary attraction between -
the slots 24 and the molten brazing material 44 to prevent the material from
flowing out of slots 24 regardless of the attitudes of the slots. - -
It is also understood that the following claims are intended to
cover all of the generic and specific features of the invention herein des-
cribed and all statements of the scope of the invention which might be said
to f~ll therebetween.
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