23
51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
P40= 12
Palmer-Bowlus flume (rectangular)
Palmer-Bowlus flumes make a transition from a circular
bottom section to a raised trapezoidal throat and then
transition back to the circular bottom section.
The range (P04) value is larger than the reference distance
(P46) as shown at left. Enter values for P40, P41, P42,
and P46.
P40= 13
Khafagi Venturi flume
The flow through a Khafagi Venturi flume is derived from
the following equation:
Q[m
3
/s] = P42*1.744*h
1.5
+ 0.091*h
2.5
Enter the values for P42 and P46 as shown at left.
P40= 14
Bottom step weir
The flow through a bottom step weir is derived from the
following equation:
Q[m
3
/s] = 5.073*P42*h
1.5
Enter the values for P42 and P46 as shown at left.
P40= 15
Rectangular weir without end contractions
This is also known as suppressed rectangular weir, in that
there are no contractions at the ends of the weir. The range
(P04) value is larger than the reference distance (P46) as
shown at left.
Q[m
3
/s] = 1.7599*[1+(0.1534/P41)]*P42*(h+0.001)
1.5
Enter values for P40, P41, P42, and P46.
P46
P04
P42
D/10
D
P41
h
Sensor
Sensor
P42
P46
h
15 cm
P46
P42
h
P46
P04
P41
h
P42
