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oct. 29, 194e.
' 2,410,201
Filed April 26,1944
_Il N
Patented Óct. 29, y:19426K
,410,291.1 .,
Philadelphiaïî Pa., `assign
otiye Works', ‘afcòrporatión
Applicatiorinpm c, 194.4;y »Seria
'Y "
' "
'zel-assi (ci.44V
This invention relates to plate steel volute
casings for rotary hydraulic machines such as
hydraulic turbines and pumps.
3 and at the same time place the rivets
under double shear, I machine a groove 9 and a
' vanes
small rib I0 circularly around the stay vane ring
preferably on the uppermost and lowermost sur
of the respective walls and the plate metal
heads considerable diiiâculty is frequently experi CII faces
Il of the casing is ñtted against the rib I0. A
enced in obtaining proper flow velocity conditions
rivet strap I2 is anchored to the ring by being
within the casing primarily because of the in
provided with a circular key I3 which fits into
ability to have'certain portions of the plate steel
the keyway 9.' Rivets I4 .extend through the stay
casing _of sufficiently small radius of curvature at
ring, plate and strap I2 and are placed in
the points where the casing joins the usual stay lo vane
double shear by reason of the strap I2 being
vane ring especially at the small cross-sections of
keyed to and forming in elîect a rigid part of
the casing. This difficulty has heretofore arisen
the stay ring structure itself. Hence, when the
because of the necessity to provide an extended
casing is subjected to internal water pressure so
When volute casings are used under certain
straight portion of the plate steel casing adja
cent the stay vane ring in order toemploy usual
4riveted butt straps on each side of the 'casing
joint and thereby place the rivets in double shear.
that the plate I I is placed under tension the load
will be transmitted directly to the stay ring
through the rivets and to the plate I2 which in
turn transmits the load to key I3 and thence to
stay ring. LIn this manner it is possible to
improved combination of elements whereby a
the excessive space that is normally
plate steel casing of a rotary hydraulic machine
required to produce a double strap riveted joint
may have a relatively small radius ofcurvature
which has been necessary in order to place the
adjacent the stay vane ring and particularly at
rivets in double shear. Hence, with my improved
the small cross-sections of the casing, in the case
arrangement, it is possible to obtain more ideal
of a volute, where the problem of making small
25 flow conditions within the casing particularly at
radii of curvature is particularly acute.
the'small cross-section because of the ability to
Another object is to provide an improved com
start a small radius of casing curvature close to
bination of elements for obtaining small radii of
the stay vanes.
curvature, of a plate steel casing,.adjacent the
The modification shown in Fig. 3 allows the
stay vane ring and still cause the rivets to’be in
30 curvature of the casing to start very abruptly ad
double shear.
jacent the stay vane ring I1, this being accom-V »
Other objects'and advantages will be more ap
plished by providing a plate metal supporting
parent to those skilled in the art from the fol
I8 of suliìcient depth on the stay ring
lowing description of the accompanying drawing
so that the plate metal casing 20 extends to a
in which:
midway of the radial depth of
35 Ypoint 2| about
Itis an object of my invention to provide an
Fig. 1 is a partial sectional view through a cas
ing and a portion of a hydraulic turbine;
Fig. 2 is an- enlarged fragmentary sectional view V
the guide vane I9. To provide a ñrm anchor for
the'rivet strap 22 it extends inwardly over the
whole of the upper end of the stay vane ring
with a substantial flanged end of key 23 which
Figs. 3 and 4 areV enlarged sectional views
overlaps the inner edge 24 of the stay vane ring.
showing modiñed forms of arrangements by plac
Rivets 25 secure the component elements to
- ing the rivets in double shear.
gether and the rivets are placed in double shear
The particular embodiments of the invention
of the casing joint shown inFig. 1; and
' - disclosed herein have been applied for purposes
by virtue ofplate 22 being anchored at 23 and
24. The lianged end 23 of the strap plate is
of illustration to a Francis type hydraulic turbine
including a runner I, adjustable guide vanes 2 45 fitted within the corner 26 of the head cover -21
well-known in the art. f
and stay vanes 3 which are secured at their upper
In the modification shown in Fig. 4, the cas
and lowerends to flow guidingportions 4 and 5
ing plate 30 is placed on the inside of the stay
extending as a'surface of revolution around the
ring 3I while a rivet strap 32 has a key 33 seated
runner axis. The stay vanes and portions 4 and
5’are usually cast'integrally from a stay 'vane 50 in a circular keyway of the stay vane ring. The _
rivets 34 will be placed in double shear by reason
ring. A plate steel casing 6, generally of volute
of the inside strap being anchored to the stay
form, well-known in the art, is usually riveted to
the edges of the stay ringk elements 4 and 5. In
From the foregoing disclosure of the several`
order to allow the casing to start its curvature 'I
as close as possible to the edge 8 of the guide 55 modifications, it is seen that I have provided an
improved arrangement of overlapping casing and
stay ring elements whereby the casing plates may
overlapping one side of said plate steel casing
near its edge portion, a rivet strap overlying the
other side of the Vplate steel casing, and means
for anchoring said strap to the stay vane ring
be curved very closely to the stay vanes 8 thereby
to permit desirable velocity and ñow conditions
to be obtained While at the same time insuring
by a direct abutting contact with a transverse
maximum structural strength to thesjoints be
surface on said ring whereby rivets extending
tween the Acasing`v` and stay vanev ring. It is, =of
course, to be understood that the keyed straps
through said strapy plate and ring will be placed
in doubleshear to provide'necessary strength and
will be formed in segmental lengths.
to allow curvature of the casing at its small sec
It will of course be understood that various
tions to start adjacent the stay ring thereby to
changes in details of construction and arrangee
ment of parts may be made by those skilled in
the art Without departing from the spirit of the
invention as set forth in the appended c1aims.,.
I claim:
obtain more desirable flow conditions through the
volute casing.
2. The combination set forth in claim 1 further
characterized in that a head cover is provided
with a recess to receive said stay vane ring, and
1. A rotary hydraulic apparatus comprising, in
said ring has an annular ledge at its innermost
combination, a stay vane ring and .a volute plate
‘edge and the strap has a flanged portion seated
steel casing therefor having certain small sec
in saidvrecess and overlapping and engaging said
tions that are relatively small compared to oth
ers, said stay vane ring having a portion 20
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