FMI Pumps Application TipsFMI Metering Pumps & Dispensers -
Application Tips

At Fluid Metering, Inc., we are dedicated to providing all of our customers with the highest quality valveless metering pumps, the very best service and technical support. To further our quality goal, we have put together these application recommendations. We hope you will find these tips beneficial. For assistance with a specific application or for custom design support, use our secure Application Request Form to provide us with details of your project. One of our specialists will contact you to target a solution. Or use our LiveHelp to chat with an application specialist.


PRESSURE:

In most FMI pump models, motor starting torque is the limiting factor in the stated pressure rating. Fluids such as oils, creams and gels that are good lubricants are more easily pumped than aqueous or "dry" fluids and therefore require less motor torque and may be pumped against pressures considerably greater than those given in the rating charts.
All pump head components are designed to withstand backpressures up to 100 psig at room temperatures, though pump heads with fluorocarbon cylinder cases may exhibit some loss of pumping capacity at pressures over 60 psig.

ACCURACY:

FMI pump accuracy is based on a simplified positive displacement mechanism. The valveless design provides a presision of better than 0.5% when handling medium viscosity fluids (50 to 500 centipoise). Aqueous solutions and light solvents work well but may exhibit some sensitivity (fluid slip) to variations in discharge head pressure. Gums, gels and non-abrasive semi-solids are handled with a high degree of accuracy. A direct result of the valveless design.

Viscous, tacky solutions, semi-solids and heavy slurries which tend to resist (cavitate) suction flow into a pump head can be handled with ease by selecting an FMI pump employing a relatively slow reciprocation rate.
The principal flow rate deviations of an FMI pump are fluid slip and stroke repetition rate. These two factors in turn are related to load factors such as viscosity, differential pressure, and drive motor voltage. When these two factors are controlled, the FMI pump will handle most fluids with reproducibility of better than 0.5%.

GAS PUMPING:

Due to the valveless design of the FMI pump "CKY" and "CSY" pump heads are able to perform accurate gas transfers. With no valves to introduce random compression errors, gas sample flow in bagging, scrubbing and transit operation can be accurately preset based on actual piston displacement.

IMPORTANCE OF CLEAN FLUIDS:

While a certain amount of caution must be exercised in the use of abrasive fluids in any metering pump, the "CKC" and"CSC" tend to be more tolerant of suspended solids than other metering pumps. To assure fluid compatibility, consult the Materials of Construction information above.

FOR BEST PUMPING RESULTS:

Select an FMI Pump having a maximum flow rating as near to the desired flow rate as possible.