Tecfluid FLOMID User Manual

Electromagnetic

sensor

instrumentation

for fluids

Series

FLOMID FX

Instructions Manual

Conforms with the Pressure Equipment Directive 97/23/EC.

This equipment is considered as being a pressure accessory and NOT a safety accessory as defined in

!

the 97/23/EC directive, Article 1, paragraph 2.1.3.

R-MI-FlomidFX Rev.: 0

English version

0830

WORKING PRINCIPLE

The Flomid electromagnetic flowmeters , are based on Faraday’s induction law.

When an electrically conductive liquid flows through a magnetic field, perpendicular to the flow
direction, it induces a voltage V

, proportional to the liquid velocity.

m

Two electrodes in contact with the liquid and positioned perpendicular to the magnetic field, sense
this voltage V

.

m

Vm = B·vm·D

Where:

V

= Measured voltage in the electrodes.

m

B = Magnetic flux density
v

= Average liquid velocity

m

D = Pipe diameter.

RECEPTION

The FLOMID electromagnetic flowmeters are supplied conveniently packed for transport together
with their instruction manual for installation and operation.

All the flowmeters have been verified in our calibration rigs to obtain the factor Fc for each sensor.
Disassembly

Unpack the instrument carefully, removing any remains of the packing from the inside of the
sensor. Do not remove the grease from the neck that couples to the electronics housing.

Storage temperature

Sensors linings of : PTFE and PVDF -20ºC ...... +60ºC

PP and EBONITE -5ºC ...... +50ºC

HANDLING

It should always be done with care and
without knocks.

The large diameter sensors have rings
for holding the elevation elements. If the
flowmeter is held using slings, these
should hold on the sensor and not on the
electronics housing (see the drawing).

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INSTALLATION

This should be made in a point that guarantees that the pipe is always completely full.

Avoid high points of the pipes where air pockets usually form, or pipes with falling flow where

vacuums can form.

Partially full pipes can produce important reading errors.

Flow rate measurement

with open discharge
makes it necessary to
install the flowmeter in a
pipe section with a siphon
which avoids stagnation of
air in the sensor.

Sensor position

The most adequate position is
with the electrodes in a
horizontal plane. In this way,
deposits of particles on the
electrodes are avoided.

Straight pipe sections

Are necessary before and after the
sensor. The minimum distances are
the following:

Upstream : 5 DN

Downstream : 3 DN

In installations with turbulent flow it
may be necessary to increase these
distances.

Mixtures

If liquids of different conductivities are mixed it is
necessary to install the sensor a minimum of 30 DN
from the point of mixture in order to obtain a uniform
conductivity of the liquid and stabilize the readings.

If this distance is less, the readings may be unstable.

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