Instruction manual

Page 106
Example 3 BS3680 Rectangular Weir
In this example it is required to calculate to the flow through a BS3680
Rectangular weir. Absolute calculation will be used, and there is a
requirement for an alarm to indicate a high flow condition to be set to relay
3. The flow rate is required to be displayed in US gallons/minute and the
totaliser is to record the flow in thousands of US gallons, the resettable
totaliser is to be displayed during RUN.
The distance from the end of the transducer horn (dB Mach 3) to zero flow
(P105) is 40 inches and max head (P704) is 16 inches, maximum flow
(P705) which will be calculated by the Ultra unit as 2385.63 USG/Min.
Approach width (Dim”A”) P710 = 18 inches
Crest width (Dim “B”) P711 = 12 inches
Crest Height (Dim “C”) P712 = 10 inches