Series 1250 Pneumatic Chemical Injection Pump
Operating Manual
Page 7 of 19
It is not necessary to remove most liquids, such as distillate carryovers, from the supply gas. The
pump will not stall no matter how much liquid reaches the air/gas inlet. However, alcohols such as
methanol can attack the seals in the motor end of the pump, and should be removed prior to
reaching the pump air/gas inlet. Alternatively, if alcohols or other unusual liquids will be present in
the supply gas, CheckPoint can supply other seal materials for the motor.
CAUTION: Always use a gas pressure regulator if the possibility of supply pressures in excess of 200
psig exists. Allowing higher gas pressures to enter through the air/gas inlet will most
probably result in damage to the motor seals. Also, such pressures will translate into
excessive discharge pressures, which can rupture chemical discharge tubing.
Take care to prevent debris in the supply gas line from entering the main spool housing and
switching valves, where it could accelerate seal wear and damage the main switching valve
components.
In situations where sand, dirt, and other particulate matter may be carried in with the supply gas, a
CheckPoint ST Series In-Line Filter or a gas scrubber is recommended.
NOTE:
To find the Amplification Ratio for your pump, please see Figure 2 below.
NOTE:
If this formula yields a result of < 20 PSIG, use 20 PSIG as your supply pressure.
pump does not require a pressure regulator when operated within these recommended supply pressures, as long
as the supply pressure remains relatively constant ( 5%).
1.3.2 Liquids may also be used as a driver fluid, but pump speed will vary widely with the liquid viscosity. Call
CheckPoint for performance data for the liquid you intend to use.
1.3.3 Blow the supply gas line clean to remove all foreign matter and debris.
1.3.4 Connect the supply gas line to the 1/4" NPT female connection on the housing. To ensure positive injection,
the supply gas pressure should be a minimum of 20 PSIG and a maximum of 200 PSIG, set according to the following
formula:
REQUIRED GAS INLET PRESSURE
=
[DISCHARGE PRESSURE]
X 1.3
[AMPLIFICATION RATIO]
1.3.5 Faster pump speeds can be obtained by increasing the gas inlet pressure from the minimum required by the
formula above.
CP/MAN-PRD-015 REV. 15 EFF. DATE: 07/08/2022
