D
R
A
F
T
Micropilot FMR53, FMR54
36
V. 1, Rev. 7, 26-10-2012
Hauser
Measuring conditions
• In case of
boiling surfaces
,
bubbling
or tendency for
foaming
use FMR53 or FMR54. Depending on its
consistence, foam can either absorb microwaves or reflect them off the foam surface. Measurement is
possible under certain conditions. For FMR50, FMR51 and FMR52, the additional option "Advanced
dynamics" is recommended in these cases (feature 540: "Application Package", option EM).
• In case of heavy
steam development
or
condensate
, the maximum measuring range of FMR50,
FMR51 and FMR52 may decrease depending on density, temperature and composition of the steam
®
use FMR53 or FMR54.
• For the measurement of absorbing gases such as
ammonia NH
3
or some
fluorocarbons
2)
, please use
Levelflex or Micropilot FMR54 in a stilling well.
• The measuring range begins, where the beam hits the tank bottom. Particularly with dish bottoms or
conical outlets the level cannot be detected below this point.
• For stilling well applications, the zero should be positioned at the end of the tube, as the electromagnetic
waves do not propagate completely outside the tube. It must be taken into account that the accuracy may
be reduced in the area
C
. In order to guarantee the required accuracy in these cases, it is recommended to
position the zero-point at a distance
C
above the end of the tube (see figure).
• In case of media with a low dielectric constant (
e
r
= 1.5 to 4)
3)
the tank bottom can be visible through the
medium at low levels (low height
C
). Reduced accuracy has to be expected in this range. If this is not
acceptable, we recommend positioning the zero point at a distance
C
(see figure) above the tank bottom
in these applications.
• In principle it is possible to measure up to the tip of the antenna with FMR51, FMR53 and FMR54.
However, due to considerations regarding corrosion and build-up, the end of the measuring range should
not be chosen any closer than
A
(see figure) to the tip of the antenna.
• When using FMR54 with planar antenna, especially for media with low dielectric constants, the end of
the measuring range should not be closer than 1 m (3.28 ft) to the flange.
• The smallest possible measuring range
B
depends on the antenna version (see figure).
• The tank diameter should be greater than
D
(see figure), the tank height at least
H
(see figure).
100%
0%
B
A
C
H
øD
A0018872
Device
A [mm (in)]
B [m (ft)]
C [mm (in)]
D [m (ft)]
H [m (ft)]
FMR53
50(1.97)
> 0.5 (1.6)
150 to 300 (5.91 to 11.8)
> 1 (3.3)
> 1.5 (4.9)
FMR54
2)
Affected compounds are e.g. R134a, R227, Dymel 152a.
3)
Dielectric constants of important media commonly used in the industry are summarized in the document SD106F, which can be downloaded from the
Hauser web page (www.endress.com).
Содержание Micropilot FMR53
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