Appendix E Calculating Flow Increment Between Samples - Teledyne 3700 Installation And Operation Manual

3700 Portable Samplers
Appendix E Calculating Flow Increment Between
Samples
The 3700 Sampler will accept flow-proportional inputs from an
external flow meter or flow logger. These electronic flow-input
signals are transmitted to the sampler at fixed increments of
total flow, for example, every 10,000 gallons. Each time 10,000
gallons of liquid flows past the flow meter, it sends a signal to the
sampler, which registers it as a single flow pulse. You can
program the sampler to totalize any number of flow pulses from 1
to 9,999 before initiating a sampling event. For example, if the
sampler were programmed to totalize 5 flow pulses and each flow
pulse represented 10,000 gallons of total flow, a sample would be
collected each time 50,000 gallons (5 flow pulses of 10,000 gallons
each) had passed the flow meter.
Time Interval Known – If the desired average time interval
between individual samples is known, the flow increment
between samples can be determined by calculating how much
flow (based on the average flow rate) occurs during that time
interval. For example, assume that the average flow is 2.5 MGD
and it is desired to collect a sample every 30 minutes. The flow
increment between samples is calculated:
2,500,000
736
Thus, the desired flow increment between samples is approxi-
mately 52,000 gallons.
Number of Samples Known – A l t e r n a t i v e l y, i f t h e t o t a l
number of samples to be collected over the total sampling period
is known, the flow increment between samples can be deter-
mined by calculating how much total flow will occur during the
sampling period, and dividing this by the total number of
samples to be collected. For example, assume that the average
flow is 1.75 MGD, that the composite sampling period is 2 days,
and that it is desired to collect 100 individual samples. The flow
increment between samples is calculated:
Thus, the desired flow increment between samples is approxi-
mately 35,000 gallons.
2.5 MGD = 2,500,000
/ 1 /24
GAL DAY X DAY
/ 30 /
GAL MIN X MIN SAMPLE
1.75 MGD = 1,750,000
1,750,000 /
GAL DAY X
3,500,000 ÷ 100
GAL SAMPLES
/
GAL DAY
1 /60 = 1736
HR X HR MIN
= 52,080 /
GAL SAMPLE
/
GAL DAY
2 = 3,500,000
DAYS GAL
= 35,000 /
GAL SAMPLE
/
GAL MIN
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