Levelogger Series User Guide
Page 75
10.1.5 Installation in Extreme Environments
10.1.5.1 Freezing or High Temperature Conditions
Levelogger installation at submerged depths that may be at risk of freezing
during the water monitoring session is not recommended without taking
adequate precautions to avoid transducer damage. When water freezes
it expands approximately 9% by volume. A 9% expansion can equate
to extreme pressure as demonstrated in Example 10.1. Therefore, solid
freezing has the potential to damage the pressure transducer, which is
rated to withstand up to 200% (150% for the Levelogger Gold and Junior
Models) of its depth fluctuation range. Pressures beyond this threshold
may damage the pressure transducer. As such, care should be taken when
choosing the appropriate pressure transducer range for your application.
Example 10.1 Solid Freezing Effects
The pressure exerted by the physical expansion or ice crystallization
process on a retaining or enclosing contact surface is related to the
temperature gradient over which the process occurs, i.e. the speed
at which freezing occurs. For example, liquid freezing at -22ºC,
can create expansion pressures of 22 kg/cm
2
or 313 psi or the
equivalent of 220 m or 721 ft water column depth.
With precautions, the Solinst Levelogger can be used in freezing liquid environments. If monitoring shallow
water bodies or groundwater zones susceptible to freezing, the easiest way to avoid transducer damage is
to lower the transducer to a point in the water column below the frost line or ice formation depth. In water
bodies such as shallow streams, wetlands or ponds where freezing may penetrate to the bottom, install the
Levelogger in a vented stilling well imbedded into the bottom of the water body beyond the frost line.
Note:
Although precautions can be taken, placing a Levelogger in a situation where the water may freeze solid can
permanently damage the sensor.
In cases where the above noted precautions cannot be taken and the Levelogger must be installed in
the freezing zone, it is recommended that the logger be placed inside two elongated silicon, rubber or
latex balloons, the balloons can be filled with a non-toxic, non-corrosive anti-freeze solution and sealed
(Figure 10-22). Place the balloons in a section of perforated, 30 mm (1.25") ID pipe and install the logger in
the monitored water. The antifreeze solution will protect the Levelogger from ice expansion at the pressure
transducer, yet transmit any pressure fluctuations that occur. However, it should be noted that even if these
precautions are taken, there is still the risk that placing a Levelogger in a situation where the water may freeze
solid can permanently damage the sensor (see Example 10.1).
Please note that a similar installation protection can be used when the Levelogger is monitoring liquids which
are incompatible with its wetted materials.
The operating temperature range for Leveloggers is -20° to 80°C (-4° to 180°F). At the opposite end of
the thermal scale, exposing the Levelogger to temperatures beyond 80°C may damage the thermistor and
otherwise affect the Levelogger.
Figure 10-22
Installation in Freezing Liquid