13
To calculate pump flow rate:
Minimum Pump Flow Rate = Volume of System*
Maximum Lagtime
where Volume of system = π ( Tubing I.D.) 2 x Length of tubing
2
Maximum lagtime = Previously calculated time to get solution to sensor.
* Volume is based on length from solution to sensor, not the return.
For Example: If the system parameters are: Tubing is 3/8” O.D. ‘ 1/4” I.D.
Length is 30 feet (360 inches)
then the volume of the system = π ( 0.25 in )2 x (360 in)
2
= 17.7 in3
Note: 1 U.S. Gallon = 231 U.S cubic inches
1 Liter = 61.03 U.S. cubic inches
Note: Volume of Cooling Coil:
0.018 Gallons
0.068 Liters
Volume of Cooling Plate: 0.023 Gallons
0.088 Liters
Volume of 3/8” O.D. x 1/4” I.D. (0.59 in3/ft): 0.00255 Gallons/linear ft
0.00965 Liters/linear ft
Volume of the system = 17.7 in3 = 0.0765 gallons
231 in3 / gallon
Maximum lagtime = 0.60 minutes (previously calculated)
So, the minimum pump flow rate = 0.0765 gallons = 0.127gal/min (483 mL/min)
0.60 minutes
Caution:
The calculated pump flow rate is the minimum required to obtain the desired control band, however, if the
flow rate increases over the recommended rate of 500 mL/min (approx. 0.13 gal/min) the rate of cooling will de
-
crease. This may be compensated for by re-evaluating the system criteria: length / desired control band or to double
up on the cooling plate/coil.
Consult factory with any further installation questions.
3.6 Other Sensor Installation
Refer to the specific instructions supplied with the sensor being used, for detailed installation instructions.
General Guidelines
Locate the sensors where an active sample of water is available and where the sensors can easily be removed
for cleaning. Position the sensor such that air bubbles will not be trapped within the sensing area. Position the
sensor where sediment or oil will not accumulate within the sensing area.
In-Line Sensor Mounting
In-line mounted sensors must be situated so that the tee is always full and the sensors are never subjected to a
drop in water level resulting in dryness. Refer to Figure 3 for typical installation.
Tap off the discharge side of the recirculation pump to provide a minimum flow of 1 gallon per minute through
