Thermo Scientific Locator series Betriebshandbuch Seite 130

Section 6
LN2 Level Monitor Operation
Principles of
Operation
Microprocessor
Functions
Figure 6-3. Remote Alarm Connections Schematic
6-4 Cryogenic Storage Vessel
The innovative Thermo LN2 Level Monitor utilises ultrasonic sound waves
to sense the level of liquid nitrogen inside a Locator or Locator Plus
cryogenic storage vessel. A microprocessor control provides continuous
indication of the liquid nitrogen level inside the Locator or Locator Plus,
with accuracy to ±2". Audible and visual alarms also provide an early
warning of low level conditions.
Ultrasonic sound waves sense the level of liquid nitrogen inside the Locator
or Locator Plus vessel.
By using ultrasonic sound waves to sense the level of liquid nitrogen, no
physical probe is required to sense the level of liquid nitrogen.
Conventional devices use probes which must be in physical contact with
the liquid. This physical contact increases liquid nitrogen consumption.
There is NO increase in liquid nitrogen consumption by using the Thermo
level monitor.
The LED display is graduated in 8 segments and provides quick and
reliable visual indication of the level of liquid nitrogen inside the Locator
or Locator Plus vessel, from Full to Empty, similar to a fuel gauge on an
automobile.
U4
4
1
2 5
3 6
The position of J4 and J6 indicate
whether the relay is normally open
or normally closed.
J3-1
J3-2
Load
V Load Voltage
L
(DC)
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