Checkpoint 1250 Series, Operating Manual

Page: 10 / 19

Series 1250 Pneumatic Chemical Injection Pump
Operating Manual
Page 10 of 19
Failure to reopen the Chemical Supply Valve will result in the pump quickly depleting the remaining
chemical in the gauge and running on air, necessitating pump re-priming.
In cases where the chemical flow rate is extremely low, you may need to time for longer than one
minute to allow an adequate amount of chemical to move out of the gauge.
To ensure accurate stroke rate measurement, allow sufficient measurement duration. Where
possible, allow at least thirty seconds of gauge drawdown.
At extremely slow stroke rates, only a small turn of the speed control valve is required to alter the
stroke rate, so if readjusting the rate of the pump, it is helpful to turn the valve only a small increment
(a couple of angular degrees) at a time.
near the bottom of the gauge, or when one minute has expired (whichever comes first), stop timing, note the ending
level on the gauge, and reopen the Chemical Supply Valve.
3.2.1.7 Write down the amount of time in seconds and the final gauge reading, then close the Gauge Fill Valve.
3.2.1.8 The pumping volume (in the units specified on the gauge scale) will be given by the following equation:
PUMPING VOLUME =
[END READING] – [BEGINNING READING]
X 60
[DURATION OF READING IN SECONDS]
3.2.2 Calculation of Stroke Rate
It is possible to calculate your pump’s required stroke rate. To do so, you have to look up a volume factor, multiply
it by your desired chemical flowrate requirement, compensating for the discharge pressure using a graph. The
instructions below will detail this process. This is most helpful when determining if a particular plunger or pump size
will output a required volume.
3.2.2.1 Using your desired chemical flow rate, calculate an Unrated Stroke Rate (USR). UNRATED STROKE RATE
(USR) (STROKES/MIN) = FLOWRATE (QT/DAY) X VOLUME FACTOR. Figure 3 contains basic conversions to assist
you. Figure 4 gives the Volume Factor used to determine the USR.
FIGURE 3: GENERAL CONVERSION TABLE
TO CONVERT: TO: MULTIPLY BY:
GALLONS QUARTS 4.00
LITERS QUARTS 1.058
CUBIC INCHES QUARTS 0.0173
MINUTES DAYS 0.000694
CP/MAN-PRD-015 REV. 15 EFF. DATE: 07/08/2022