Frequently Asked Questions
FMI are dedicated to providing all of their
customers with the highest quality valveless
metering pumps, the very best service, and
technical support. To further their quality
goal, We have put together a list of
frequently asked questions about FMI pumps .
We hope you will find these answers
Frequently Asked Questions
What is the accuracy of the FMI Pump ?
Accuracy of ± 1%. Can be expected for low to
medium viscosity (1 - 500 cps) fluids
providing, consistent precise output from
microlitres to full flow range.
Q. How do I Identify which FMI
pump I have ?
Find the serial numbers on your unit and
contact FMI customer service. From the
serial numbers, FMI can tell you all about
Why is my pump
making a hammering sound
hammering sound is usually an indication of
CAVITATION. Cavitation is caused when the
suction side tubing ID is too small to allow
adequate flow of fluid to the pump.
CAVITATION can cause problems such as
hammering, flow variation, bubble formation,
loss of prime and eventually pump damage.
Q. Is the FMI Pump self
Yes, FMI pumps will self prime to 15 feet
vertical dry or 26 feet wet
Q. Can the
sanitary pump heads be autoclaved or
YES, FMI Sanitary Pump heads are designed
for autoclaving, clean in place, or complete
disassembly for brush cleaning. Cleaning
procedures can be followed without loss of
system operating efficiency.
Q. What is dead volume ?
Dead volume is the
amount of fluid which remains in the pump
when the fluid discharge is completed. For
low volume dispenses or low flow rates, FMI
has special low dead volume pump heads
signified by the suffix "LF", which utilise
low flow fittings that facilitate bubble
clearing in the pump.
Q. How do I
adjust my FMI pump for a specific rate ?
On all FMI pumps, flow rates may be altered
when operating or at rest. On the “Q” line
this is done by turning the Flow Control
Knob which moves the flow rate indicator
along a fixed 20 unit scale linearly
calibrated “10-0-10”. The “10” equals 100%
flow rate in that direction, “0” equals zero
flow. To improve the fine adjustment of the
flow rates on the “Q” line, there is an
optional Dial Indicator Kit Q485 which
provides for 1000 discrete settings. The
“RH” line flow adjustment is accomplished by
turning an easy-grip Flow Control Ring
graduated in 450 divisions from 0 to 100%
Q. What are the pressure
limitations of PVDF Pump Heads ?
PVDF pump heads have an operating
temperature rating of 212 deg. F (100 C).
However, these pump heads can be autoclaved
(non-operating) at temperatures up to 240
deg F (116 C).
Q. How can I increase the
flow adjustment accuracy on the "Q" pump
The Q485 Dial Indicator accessory is
available for "Q" pump heads which provides
direct reading of pump head position in 0.1%
increments for ultra-fine flow rate
adjustment. It can be ordered with the pump
Q. How can I monitor the
speed (RPM) of my FMI pump ?
A variety of rotational sensors are
available which will provide a signal for
monitoring RPM. For pumps which utilise the
standard Q style base, hall effect and
proximity rotational sensors are available.
For stepper motor driven pumps, Opto-sensors
can be provided.
Q. Can I mount an RH style
pump head on my Q style base ?
Yes. The RH/Q adaptor adds versatility to
your Q pump. It is a quick, easy, low cost
solution for mounting RH pump heads to a Q
Q. When should I select a
low flow pump head and fittings ?
In general, when the flow rate is 50 ml/min
or below, a low flow pump head, designated
by the suffix "LF" should be used. These
pump heads have very low dead volume and
accept 1/4-28 fittings used with small bore
tubing for zero dead volume connections. FMI
offers the Small Bore Tubing Kit Q661
combinations for 1/8" and 1/16" small bore
tubing which include tubing and fittings.
These fittings connect directly to PVDF and
Tefzel® "LF" pump heads. For use with 316SS
pump heads (except SAN), the R479 adaptor is
Q. How does viscosity
affect the accuracy of the FMI pump ?
The FMI pump is positive displacement and,
in general, viscosity independent. However,
viscous fluids should use lower RPM drives
(400 RPM or less) with pump heads adjusted
to longer piston strokes. There is no
absolute value for the maximum viscosity an
FMI pump can handle. For extremely viscous
fluids, pressure feeding on the inlet side
of the pump and/or heating of fluid are
commonly used to aid in feeding fluid to the
pump. FMI also manufactures temperature
controlled pump heads "WT" to help maintain
fluid temperatures up to 360 F as it flows
through the pump.
GUIDELINE FOR PUMPING HIGH VISCOSITY FLUIDS
FMI pumps are
considered viscosity independent indication
that most high viscosity fluids can be
dispensed or pumped at low flow rates and
low speeds. Free flowing fluids are easier
to pump than non-flowing fluids.
Viscous fluids up to 500 centipoise can
usually be pumped by most FMI Drives and
In most cases no additional steps are
required to achieve good performance.
Viscous fluids above 500 centipoise may
require the following steps to achieve
better results -
slower the RPM the better. Try to keep
RPM below 400.
stainless cylinder case material (CSC,
Head closest to 100% of Pump Head Module
flow rate. A longer piston stroke is
better than a short piston stroke.
largest ID suction line possible.
Increasing tubing size on discharge side
can help reduce back-pressure build-up.
viscosity if possible - try....
Heating - check temperature limits of
Pump Head Module in catalogue.
Dilute using suitable thinner.
flow to pump ....
Free flowing fluids should be gravity
Non flowing fluids may require the use
of a pressure pot to get fluid into pump
Dispensing small drops of high viscosity
fluids may require physically moving the
dispenser head to the point of delivery
and making contact at that point
“touching off”. This will help prevent
the drop from remaining on the dispenser
viscosity fluids may require modified
ceramic Piston-Liner sets. Consult
How do I know what pump head materials are
compatible with my fluid
FMI can search through our
reference material as well as our
comprehensive application database to make
recommendations. However, a quick and easy
way to determine compatibility is to
consider what materials of construction are
currently used in your piping, fittings,
vessels, and containers to handle your
product. There are also reference
compatibility charts available in print and
online. The chemical manufacturer's MSDS
data sheets may contain compatibility
information as well.
Q. What is the maximum
dispense volume of the FMI pump ?
The FMI pump can dispense up to 1.28 ml per
piston stroke. However, larger volumes can
be dispensed using stepper driven pumps
which can dispense up to 7 strokes (8.96 ml)
with a single dispense signal. For larger
volumes, FMI continuous metering pumps can
be used in conjunction with a 3-way diverter
valve and a timer. Contact FMI customer
service for more information.
Q. How do I prevent fluid
splashing when dispensing into a small vial,
cuvette or micro plate well ?
Fluid splashing when dispensing is caused by
the fluid being dispensed at a high
velocity. The fluid velocity can be
decreased by either reducing the drive RPM
or by changing the dispense tip to one with
a larger orifice. Dispense tip design can
have an influence on the velocity and
pattern of dispensing to reduce splashing as
Q. Do I require two
separate pumps to proportionally meter two
different fluids at different flow rates ?
No. FMI's Ratio:Matic® pumps can meter two
different fluids proportionally up to 100:1
ratio. The two pump heads are driven by a
single variable speed drive motor and can
maintain the fluid ratio while infinitely
varying the overall flow rate. Ratio:Matic®
pumps include the QB2 12/24 VDC drive, QV2
with V200 Controller, and a variety of
stepper driven duplex pumps.
Q. Can I use FMI's
CeramPump® pumping technology with my
existing drive motor ?
Yes. FMI's can be easily driven by belt,
chain, or shaft coupling, or connected
directly to special motor drives. FMI can
also provide adaptors to connect QP and RH
motorless pumps to Masterflex® LS drives.
Do you have a 56C face motor ? FMI's P56C
Adapter Kit will provide an easy connection
of FMI's QP motorless pump to your NEMA 56C
face foot mount motor.