The Dethridge Meter 
9 
TABLE I— DIMENSIONvS OF DETHRIDGE METERS. 
(I.etters Refer to Figs. 2 and 3.) 
SIZE OF WHEEL. 
— i 
Feet — 
— 5 
Feet — 
— 6 
Feet- 
A . 
2' 
0 " 
2' 
6 " 
3' 
6 
ft 
B . 
4' 
3 1/4 " 
5' 
3%" 
6' 
4% 
tf 
C . 
2' 
2%" 
2' 
9 1/2 " 
3' 
10 7/8 
ft 
D . 
. . . 10' 
0 " 
12' 
8 " 
15' 
0 
ft 
E . 
6' 
8 " 
8' 
5 " 
10' 
0 
ft 
F . 
8 " 
10 " 
12 
ff 
G . 
1' 
0 9 /16" 
1' 
3 11/16" 
1' 
6 7/8 
tf 
H . 
1' 
7 ■" 
1' 
11 '' 
2' 
3 
ft 
I . 
. . . . 1' 
3 " 
1' 
6 " 
1' 
8 
ft 
J . 
4 " 
6 " 
9 
ft 
K . 
2' 
8 " 
2' 
0 " 
3' 
0 
ft 
L. 
1' 
2 \ " 
1' 
7 1/2 " 
2' 
1 
ft 
M. 
1' 
1^" 
1' 
6 1/2 " 
1' 
101/4 
tf 
N. 
2' 
6 " 
2' 
0 " 
3' 
0 
ff 
0. 
4' 
0 " 
4' 
0 " 
5' 
6 
ff 
P. 
2' 
014 " 
2' 
6t4" 
3' 
01/4 
ft 
❖ 
Of 
9 " 
3' 
3 " 
4' 
0 
0 
ft 
*Ivength of 1-inch pipe for axle. 
diagrams represent the average coodition. The irregularity of the 
points in Fig. 4 plotted from the experimental values is not due to 
error, but is due to changed conditions of flow in the ditch during 
the several experiments. 
Experiments were made to determine the effect of various 
changes in the shape of the box. The uprising lip of the floor was 
eliminated and the wheel was set lower in the ditch to give the same 
submergence of the vanes, but this change resulted in no' advantage 
whatever. It interfered with the flow of the water, and decreased 
the capacity of the wheel as much as 20 per cent. 
The normal capacities of the 4, 5 and 6 foot diameter wheels 
are ^ to second feet, i to 4 second feet and i to 8 second feet 
respectively. They may carry an additional i or 2 second feet, but 
there is a greater loss ol head, and the force of the blades is such 
as to splash water over the sides of the box. It also results in exces¬ 
sive washing of the banks below the box. The wave action caused 
by the wheel under normal operation recjuires some bank protection 
below the box. 
The principle value of the Dethridge meter is that it integrates 
or adds up all the water that is passed through the meter, regardless 
O'f any changes that may have occurred in the rate of flow, and it 
also keeps a record of the total amount. It is therefore, a total flow 
meter, but may also be used to indicate the quantity flowing at any 
certain time. 
To determine the quantity of water flowing through the meter 
at any time, count the number of revolutions of the wheel in one 
