Selecting a Metering Pump

These links may guide you.

With a benign fluid of reasonable gravity, I don't think it matters much which type you use.

Match the pump capacity to the volume of fluid being injected and pick one.

You can probably get higher pressures with a plunger/piston pump if you care.

Diaphragm pumps reduce the likelihood of leaks of the pumped fluid.

Milton Roy > Standard Product > mRoy Series Metering PumpI Have had great succsess with this style of pump.

I too have had good results with the Mil Roy pumps.Very accurate,very durable.They are available with a micrometer-style flow adjustment dial that is easy to adjust.For precision injection, they cannot be beat(IMHO).

There are several weakness in a diaphragm pump.Mainly, the diaphragm.It will eventually fail due to flexure stresses.And accuracy is not as good as a piston type pump.

Piston pumps can operate into a higher pressure process stream.

Diaphram pumps tend to have an accuracy in the 1% range, whereas piston pumps can be accurate down to 0.5% range.

Since the product being moved is a corrosion inhibitor, you may have assumed this to be non-corrosive, but this is not always the case, so you need to check the materials compatibility among any of the pump candidates you now have.

Some chemical pump manufacturers have people "fooled" into believing their pumps are piston pumps when in fact the piston only provides motive hydraulic pressure against a metallic diaphragm that actually moves the fluid.

If you want speed and stroke controls both on the pump, or automatically controlled speed, the best answer is a solenoid operated diaphragm pump. I have used these with great success on nearly any corrosion inhibitor blend you can imagine, even things such as sulfuric acid, and caustic soda (which are not "corrosion inhibitors" and which are highly corrosive chemicals).

Be sure and consider the upper pressure rating of the pump against pump capacity against the pressure and flow rate you need, and consider the ultimate turn-down ratio of the pump against the varability you require. Usually higher turn-down ratio will provide more precision of control. Precision is actually more useful in these applications than is accuracy, since either manual or automatic adjustment of the pump will fine tune the result to dead-on accurate dosing. Yes, of course, the pump must perform well in a 200-500 mL draw-down test relative to pump setting and capacity.