537 OF ENGINEERING FORMULÆ.
Jonval’s Turbines—continued.
CONSTRUCTION OF BUCKETS.
On the line BB set off the distances of the
buckets apart a, a1, a2, and from the points a, a1, a2
draw the lines a b, a1 b1, a2 b2, at an angle of ’12°
with the line B B; from the points a, a1, a2, set off
lines a c, a1 c1, &c., at right angles to the line « b,
a1 b1; the lines a c, a c, determine the lengths
of the straight portion of the buckets; then on
the lines a c1, a1 c2, from the point b b\ lay off
distance b c1 b1 c2 = depth of the buckets; then
the point c’ c2 are the centres from which the
curved portions of the buckets are described, with
a radius = depth, of buckets.
The guides are constructed in the same manner,
but with a difierent radius and angle, as below. ’
_ BUCKETS.
Radius of curved portion of bucket = Depth of
bucket D.
* Angle of straight portion of bucket = 12° with
horizontal line.
Length of straight portion of bucket = Distance
of buckets apart on the horizontal line.
GUIDES.
Radius of curved portion of guides = Depth of
guides.
* Angle of straight portion of guides = 15° with
horizontal line.
Length of straight portion of guides = Distance
of guides apart on the horizontal line.
When the buckets and guides are made entirely
straight—
Angle of bucket - 24° with horizontal line.
Angle of guide« = 66° „
* When the quantity of water is large these angles may be
increased.