THE PELTON AND SIMILAR TYPES 89
wheel and thus are proportioned to resist the stresses due to centrif-
ugal force, which are greater near the center. The first claim of
this patent is for "the combination in a turbine wheel of radial
buckets separated from each other for a part of their length, each
bucket having its receiving face channeled for the greater portion
of its length, and a pair of flat disks inclosing said buckets from
their inner ends for a greater portion of the length of the channeled
part of the buckets." In Fig. 14 A and B are two sectional views
B
SECTION ON X-Y
A
3324 -n-
G
F
H
SECTION ON M-N
Fig. 14. Wheels Patented by Zoelly.
of the wheel, C, an enlarged front view of one of the blades, and
D and E, enlarged sections of the blade on the lines x y and m n
respectively.
At F and G are details of a wheel now used in the Zoelly tur-
bine described in a subsequent chapter. In this type, patented in
1903, the steam is directed against the blades on one side of the
wheel and escapes on the other side. Sections of the blades are
shown at H. The first claim is for a "turbine blade constructed
with a gradually increasing longitudinal thickness and a longi-
tudinal cavity of substantially uniform depth." Some of the other
