Teledyne 3700, Installation And Operation Manual

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3700 Portable Samplers
Appendix E Calculating Flow Increment Between Samples
E-2
Calculation of Number of Flow Pulses – O n c e t h e d e s i r e d
flow increment between samples is known, the number of flow
pulses to be programmed into the sampler may be calculated,
assuming that the volume of the flow pulses from the flow meter
is known. The number of flow pulses is calculated by dividing the
flow increment between samples by the volume of each flow
pulse. Using the first example above, the flow increment between
samples was calculated as 52,000 gallons; assume that each flow
pulse represents 10,000 gallons of flow. The number of flow
pulses to be programmed into the sampler is calculated:
52,000
GAL
÷ 10,000
GAL
/
FLOW PULSE
= 5.2
FLOW PULSES
Rounding this to an even number results in 5 flow pulses to be
programmed into the sampler. This in turn results in a flow
increment between samples of 50,000 gallons (5 flow pulses
×
10,000 gallons/flow pulse).
Total Number Of Samples – To calculate the total number of
samples to be collected, three quantities must be known: the
average flow rate, the flow increment between samples (calcu-
lated above), and the total time over which the composite sample
is to be collected. The total number of samples to be collected is
determined by first calculating the total flow volume over the
sampling period, and then dividing this by the flow increment
between samples. For example, assume that the average flow is
2.5 MGD, the flow increment between samples is 50,000 gallons,
and the composite sample is to be collected over a 24 hour period.
The total flow volume over a 24 hour period is:
2.5 MGD = 2,500,000
GAL
/
DAY
2,500,000
GAL
/
DAY X
1
DAY
= 2,500,000
GAL
The total number of samples to be collected in this 24 hour period
is then calculated:
2,500,000
GAL
÷ 50,000
GAL
/
SAMPLES
= 50
SAMPLES
Thus, based on an average flow of 2.5 MGD, 50 samples will be
collected.
Calculation of Sample Volume – To calculate the volume of
each individual sample, the volume of the composite sample con-
tainer being used and the total number of samples to be collected
(calculated above) must be known. The individual sample volume
is calculated by simply dividing the volume of the composite
sample container being used by the total number of samples to be
collected. For example, assume that a 2.5 gallon (9,400 ml)
plastic container is being used, and that a total of 50 samples are
to be collected in it. The individual sample volume is then calcu-
lated:
9400
ML
÷ 50
SAMPLES
= 188
ML