Appendix d – Hach 900 MAX User Manual

Page 138

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Page 136
How to Calculate Pulses/Counts

8990apdx_pulsecounts.fm

Appendix D

2.

Calculate t.

3.

Multiply Q x t x 10.

Therefore, the value entered for

INTV = _ _ _ _ CNTS

is 39.

Example 4
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

1.

Calculate Q.

2.

Calculate t.

3.

Multiply Q x t x 10.

Therefore, the value entered for

INTV = _ _ _ _ CNTS

is 50.

Example 5
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

1.

Calculate Q.

2.

Calculate t.

3.

Multiply Q x t x 10.

Therefore, the value entered for

INTV = _ _ _ _ CNTS

is 240.

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.

t

a
n

---

1440 min

96 samples

-------------------------------

15 min/sample

=

=

=

0.26 mgd

15 min/sample

Ч

10

Ч

39

=

Q

Average Flow Rate

Maximum Flow Rate

------------------------------------------------------

70 gpm

210 gpm

-----------------------

0.33 gpm

=

=

=

t

a
n

---

480 min

32 samples

-------------------------------

15 min/sample

=

=

=

0.33 mgd

15 min/sample

Ч

10

Ч

49.5

=

Q

Average Flow Rate

Maximum Flow Rate

------------------------------------------------------

0.25 cfs

1 cfs

---------------------

0.25 cfs

=

=

=

t

a
n

---

2,880 min

30 samples

-------------------------------

96 min/sample

=

=

=

0.25 cfs

96 min/sample

Ч

10

Ч

240

=

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