SICK DUSTHUNTER T - Page 219

Operating Instructions FLOWSIC100
Gas Velocity Monitor
Product Description
8012513/03-2008 © SICK MAIHAK GmbH · Germany · All rights reserved 27
2.3.1.3 Purged Sender/Receiver Units
See table application
range on page 22 for
limitations of use.
These types are intended only for use with wet and sticky dust if the transducer surface is
in high danger of contamination.
To prevent the contamination of the transducer surface, purge-air is supplied by a purge-air
unit (see Section 2.3.6). The purge-air flow is optimized to maximize the directivity of the
ultrasound beam.
The transducer temperature is monitored by a temperature sensor.
Note: Using the FLOWSIC100 in gases with dust concentrations > 1 g/m³, the sender/receiver
units have to be installed in an angle to the flow direction of 60° (only applicable for
FLSE100-PH and PHS). The downstream sender/receiver unit (B in Fig. 2.4) has to be
equipped with a rebound protector .
Fig. 2.14: FLSE100 PM, PH, PHS
Note: At low gas temperatures, the purge-air supply can cause the temperature to drop below the
dewpoint. To minimize corrosion on the probe head as a result (for example, due to acid
formation with corrosive gas compositions), duct probes with a nominal length greater than
that actually required for the flanges with pipe must be selected for temperatures between
150 °C and 200 °C (for example, if the nominal length of the flange with pipe is 350 mm
→
a duct probe with a nominal length of 550 mm should be used). The purge-air is then heated
by the gas temperature in the probe tube, with the result that temperature drops below the
dewpoint can be minimized.
Fig. 2.15: Use of sender/receiver units with a nominal length greater than the flange with pipe
Electronics unit Connection PH/PM/PHS Duct probe Transducer
NL = 200 mm (only PM and PH)
350 mm
550 mm
750 mm
NL
Cable connection
A
A
A-A
Flange with pipe
Sender/receiver unit
Purge-air
Area heated by the gas flow
Gas flow
Duct wall
N
L
F
L
S
E
1
0
0
N
L
F
NL
FLSE100
= Nominal length sender/receiver unit
NL
F
= Nominal length flange with pipe