Hach 900 User Manual
Section 4
Page 31
8544operations.fm
Flow Proportional Operation
2.
Calculate t.
3.
Multiply Q x t.
Therefore, the value entered for
INTV = _ _ _ _ CNTS
is 4.
Example 4
You want to collect 32 samples over an 8-hour period.
You want to collect 32 samples over an 8-hour period.
Average Flow Rate = 70 gpm (average flow rate over the 8-hour period)
Maximum Flow Rate = 210 gpm
a = 480 minutes
Maximum Flow Rate = 210 gpm
a = 480 minutes
1.
Calculate Q.
2.
Calculate t.
3.
Multiply Q x t.
Therefore, the value entered for
INTV = _ _ _ _ CNTS
is 5.
Example 5
It is desired to collect 30 samples over a 2-day period.
It is desired to collect 30 samples over a 2-day period.
Average Flow Rate = 0.25 cfs (average flow rate over the 48-hour period)
Maximum Flow Rate = 1 cfs
a = 2,880 minutes
Maximum Flow Rate = 1 cfs
a = 2,880 minutes
1.
Calculate Q.
2.
Calculate t.
3.
Multiply Q x t.
Therefore, the value entered for
INTV = _ _ _ _ CNTS
is 24.
You will notice from the previous five examples that the average and
maximum flow rate can be expressed in any units, i.e. mgd, gpm, cfs, etc.
However, express the average and maximum flow rate in the same units for
any given situation.
maximum flow rate can be expressed in any units, i.e. mgd, gpm, cfs, etc.
However, express the average and maximum flow rate in the same units for
any given situation.
t
a
n
n
---
1440 min
96 samples
-------------------------------
15 min/sample
=
=
=
0.26 mgd
15 min/sample
×
3.9
=
Q
Average Flow Rate
Maximum Flow Rate
------------------------------------------------------
70 gpm
210 gpm
-----------------------
0.33 gpm
=
=
=
t
a
n
n
---
480 min
32 samples
-------------------------------
15 min/sample
=
=
=
0.33 mgd
15 min/sample
×
4.9
=
Q
Average Flow Rate
Maximum Flow Rate
------------------------------------------------------
0.25 cfs
1 cfs
---------------------
0.25 cfs
=
=
=
t
a
n
n
---
2,880 min
30 samples
-------------------------------
96 min/sample
=
=
=
0.25 cfs
96 min/sample
×
24
=