Page 1
PROCESS CONTROL
Level Switch
Mini-Switch LB 471
Page 2
2
Application
The BERTHOLD level switch is used in all branch-
es of industry, including the food industry. This
measurement system is applicable where one or
more alarm levels of liquids or bulk solids have to
be monitored. In fact, the BERTHOLD level switch
is suitable for installation on all types of vessels or
bunkers like storage tanks, hot-storage bunkers,
vessels with agitators, high-pressure reactors, cy-
clones or feeder chutes.
The Function
The operation of the measuring system is based on
the application of the radiometric measuring
principle, i.e. the physical law of absorption of
gamma radiation as it passes through matter.
This measuring principle has been proved suc-
cessful on the most difficult applications for many
years now.
Benefits
contactless
n
no abrasion
n
maintenance free
n
fail safe
n
long life time
n
no mechanical modifications
to the vessel required
1
Engineering data
Dimensions of the vessel at the
measuring position
n
Thickness and density of
each wall to be irradiated
n
Density of the product
to be measured
n
Gas density under operating condi-
tions in high pressure systems
n
Max. ambient temperature
outside the vessel
n
Dimensional drawings of agitators
or other internals in the vessel
n
required Ex-proof class
3
2
An arrangement of a level alarm switch is shown
in picture 1. The shielded radiation source is in-
stalled outside the vessel at the height at which the
alarm must be indicated. The radiation detec-
tor , is mounted at the same height on the op-
posite side of the vessel. The detector signal is
transmitted via a two-core standard cable to the
evaluation unit .
3
2
1
Picture 1
Page 3
3
GM-Detector
Especially for fluids with smooth surface, the GM Detector hits the spot. It is also
applicable for bulk material. For easy applications, it is the most cost-efficient
alternative solution.
For fast switching of 1,5 to 5s, or in order to reduce the source activity, the GM
Detector is available with two counter tubes.
Evaluation Unit LB 471
space saving, width only 4TE (0.8")
3 LED’s for status control
two line Display, illuminated
easy data input using arrow keys
easy calibration with the pushbutton "Cal"
easily toggle to the measuring reading with the pushbutton "Clear"
6
5
4
3
2
1
NaI-Detector
For bulk material which forms a cone it is essential to be able to adjust the
threshold very accurately. The NaI-Detector provides precise monitoring of the
bulk cone diameter.
Where high gas density is present in the vessel, the gamma radiation will be
attenuated strongly even when the vessel is empty. Thus, the measuring dif-
ference between material and gas is smaller. The significantly more sensitive
NaI-Detector guarantees a reliable switching function in this situation.
Super-Sens
An even higher sensitivity is achieved by using a scintillator 150/150mm in the
Super- Sens. The integrated collimator ensures a good signal to noise ratio and
reduces the background radiation interference.
The Super-Sens is used where the NaI Detector is pushed to its limits.
2
5
1
6
4
3
Page 4
Super-Sens
Apply the Super-Sens instead of a NaI Detector:
for very thick walls
for large vessels
if there is a demand for smallest source activities
to continue using existing sources
NaI Detector
Apply a NaI Detector instead of a GM Detector:
to reduce the necessary source activity
to keep the size of the shielding small
for bulk cone measurements
for high gas density in the vessel
Evaluation Unit LB 471
compact design for a 19" rack (3HE; 4TE)
permanent self-monitoring by „watch dog timer“
intrinsically safe detector connection (option)
The diversity of applicable detectors results in the optimum solution for every
application.
GM Detector
Apply a GM Detector with counter tube for vessels:
with diameter between approx. 1 to 5m
with typical wall thicknesses up to approx. 20mm
relative sensitivity: 20
relative sensitivity: 65
relative sensitivity: 1
Page 5
Software-Functionality
Standard-Mode
In order to reduce the time for commissioning, the menu "Standard-Mode" is
available. It limits itself to the parameters for standard applications and offers
the following functions:
automatic calculation of full count rate and time constant
calibration error indication by diagnostic routine
permanent error diagnostic
Professional-Mode
If you want to use additional functions, then you can switch to the "Professional
Mode" any time and without interruption.
The ”Professional Mode” offers:
alternatively manual data entry for otherwise automatic calculated parameters
automatic compensation of the empty count rate for gas pressured vessel
password protection, alternatively automatic protection
timely notice and indication of an required source exchange
modification log
error log
relay multifunctional
storage of a parameter set copy in the E²-Prom
...
Further applications from BERTHOLD TECHNOLOGIES
Density
Bulk Flow
Moisture
Page 6
Technical Data LB 471
GM Detectors
Types SZ5-GHS-3171-1/2: with Ex-proof
GHS-3172-1/2: without Ex-proof
Explosion proof ATEX: II 2G EEx ib d IIC T6
II 2G EEx de IIC T6
CSA: Class I Div. 2 Group B,C,D
Class II Div. 2 Group E,F,G
Housing stainless steel, IP 65
weight 4,5 kg for GHS 3172
6 kg for Sz5 GHS 3171
Operating temp. -40 ... +50°C (233 ... 323 K)
optional: water cooling jacket
Storage temp. -40 ... +80°C (233 ... 353 K)
Cable gland PG 16 for cable: Ø 5 ... 8mm
Cable e.g. LiYY 2x1,0 shielded
maximum 1000m, maximum 40 Ohm
NaI Detectors
Types LB 4401 .. with Ex-proof
LB 5401 .. without Ex-proof
scintillation counter
with NaI(Tl) crystal 50/50
temperature stability :
+
/-0,1%
automatic drift compensation
Explosion proof ATEX: II 2G EEx ib d IIC T6
II 2G EEx de IIC T6
II 2D IP 65 T 80°
FM: Class I Div. 2 Group A,B,C,D
Class II Div. 2 Group E,F,G
Housing stainless steel, IP 65
Weight 6 kg without collimator
18kg with collimator
Operating temp. -40 ... +60°C (233 ... 333 K)
optional: water cooling jacket
Storage temp. -40 ... +70°C (233 ... 343 K)
Cable gland M 16 for cable: Ø 5 ... 10mm
Cable e.g. LiYY 2x1,0 shielded
maximum 1000m, maximum 40 Ohm
Super-Sens
Types LB 4430 .. frontal irradiation
LB 4431 .. radial irradiation
scintillator 150/150
temperature stability
+
/-0,5%
automatic drift compensation
Explosion proof ATEX: II 2G EEx ib d IIC T6
II 2G EEx de IIC T6
II 2D IP 65 T 80°
FM: Class I Div. 2 Group A,B,C,D
Class II Div. 2 Group E,F,G
Housing stainless steel, IP 65
Weight 54 kg up to 74 kg according design
Operating temp. -40 ... +55°C (233 ... 333 K)
optional: water cooling jacket
Storage temp. -40 ... +70°C (233 ... 343 K)
Cable gland M 16 for cable: Ø 5 ... 10mm
Cable e.g. LiYY 2x1,0 shielded
maximum 1000m, maximum 40 Ohm
LB 471 · 05-2004.1000 · Id.No. 39505PR2 · Rev.02 · 05-2004
Evaluation Unit LB 4710
Types LB 4710-0XX for GM Detector
LB 4710-1XX for NaI Det. or Super-Sens
Arrangements - In a 19" rack 3HE, 4TE, IP20
max. 19 modules for 24V
max. 18 modules for 115/230V
- In a Cassette 3HE, 7TE, IP 20
for any 19" rack
- In a wall mounted housing, IP 66
max. 3 modules
Power supply 18-30V DC or 24V AC +10% -15%
option: 115/230V AC transformer
+10% / -15%, 47-65Hz
Power consumption max. 4W per module
Operating temp. -30 ... +60°C (243 ... 333 K)
Storage temp -40 ... + 70°C (233 ... 343 K)
keep dry!
Weight 0,3 kg per module
Detector connection 2 wire
option: intrinsically safe [EEx ib] IIC
Digital In for external empty
Digital Out 1 relay for min./max. (SPDT)
1 relay for failure signal
1 relay for warning signal
alternative as min./max. usable
contact load AC: max. 250V, max. 1A, max. 200VA
DC: max. 300V, max. 1A, max. 60W
ohm resistive load
Display 2 lines LCD illuminated
each line 4 digits
keyboard for data entry
keyboard lockable via password
Time constant 0,5 - 999s
Decay compensation automatic, for Co-60 and Cs-137
Timer buffered with capacitor
running period without power supply:
approx. 1 Month
Certificate for overcharging in vessels which are
used for storage water-endanger fluids
according WHG
Sources and shielding according separate leaflet
Modifications may occur without notice.
Loading...