mini flowmeter0 pages

Hoffer Mini-Flowmeter
Engineering Guide
MF SERIES FOR LOW FLOW
APPLICATIONS
New devices with low flow
measurement capability are
increasingly in demand by
industrial and laboratory users as
requirements for accurate low flow
measurement devices proliferate.
The Hoffer MF Series has been
developed to meet the need for a
low flow measurement device for
service on clean, low and moderate
viscosity liquids, and for gas
measurement applications.
The MF Series is a family of
low flow rate measurement devices
based on a pelton wheel like rotor.
The measured fluid is directed
tangentially thru a velocity nozzle
against the pelton rotor causing it to
rotate. The motion of the rotor is
sensed by the pickup coil and
converted to a pulsing output signal
where the frequency is related to
the flow rate, and the accumulated
pulses are related to the total
volume passing thru the flowmeter.
Materials Selection and
Construction
Selection of the materials of
construction is usually dictated by
the requirements of performance,
durability, media compatibility,
availability, and cost
considerations.
The materials of construction for
the MF Series are intended to
provide a standard flowmeter
configuration which will suit the
requirements of a broad base of
industrial users. Our applications
group can assist you in the selection
of options that will provide the
construction which offers the
optimum combination of useful
range, corrosion resistance and
operating life for a particular
application.
Bearing Selection
Bearings are chosen based on
media compatibility, desired turndown
range, service life, serviceability, cost,
and accuracy considerations. Several
bearing types are available including
self-lubricating, ceramic hybrid ball
bearings and sleeve constructions in
tungsten carbide and carbon
composites.
The side access port permits for
rapid inspection and servicing of the
flowmeter internals including the
bearings.
When selecting among several
chemically compatible bearings, the
ball bearing design offers the highest
accuracy and widest usable range and
may be considered the standard. It is
required for gas measurement
applications.
Field bearing
replacement may
be performed
without a
significant shift
in the original
calibration.
Tungsten carbide offers the most
durable bearing material in service
conditions where it is compatible, and
will offer the longest life in rugged
industrial liquid service.
Hard carbon composite bearings
offer properties which are nearly
chemically inert to many corrosive
fluids and are utilized for this reason in
demanding applications.