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Example 2 BS3680 U-Throated Flume
In this example it is required to calculate to BS3680 the flow through a U-
Throated Flume without any hump. Absolute calculation will be used, and
there is a requirement for an alarm to indicate a low flow condition which
will be set to Relay 1. The flow rate is to be displayed in millions of US
gallons/hour and the totaliser is also to record the flow in millions of US
gallons, the resettable totaliser is to be displayed during RUN.
The application is to be assigned to Point (transducer) 2.
The distance from the end of the transducer horn (dB Mach 3) to zero flow
(P2-105) is 35 inches and max head (P2-704) is 15 inches, maximum flow
(P2-705) will be calculated by the Ultra Twin as 0.1784 Mil USG/Hour.
The dimensions of the flume are as follows:
Approach Channel diameter (Dim “A”) P2-710 = 28 inches
Throat diameter (Dim “B”) P2-711 = 20 inches
Throat length (Dim “C”) P2-712 = 40 inches