Siemens OCM III, Instruction Manual, Page: 73 / 112

ROUND PIPE, P3 = 9
(based on the Manning Formula)
‘U’ parameters required *
U0 = pipe inside diameter D
U1 = slope (fall/run) s
U2 = roughness coefficientn
*obtain from manufacturer’s specifications.
Reference
ABSOLUTE CALCULATION, P4 = 0
¤
For flows that can be calculated by the equation:
q = K/n x f(h) x s
0.5
where : q = flow rate
h = head
K = constant
f(h) = A x R
0.66
A = cross sectional area
R = hydraulic radius
s = slope of hydraulic gradient
n = roughness coefficient
RATIOMETRIC CALCULATION, P4 = 1
¤
For flows that can be calculated by the equation:
q = q
cal
x f(h)/f(h
cal
)
where : q = flow rate h = head
q
cal
= flow rate at maximum head h
cal
= maximum head
¤
Refer to Operation \ Flow Calculation.
7ML19985AB01 OCM III 74