Liquid Nitrogen, Carbon Dioxide, Argon, Oxygen and LPG
are all sub-zero fluids just so perfect for a Coriolis
mass flowmeter. Their fluid properties change wildly with
small variances in temperature. The only problem is most
meters on the market literally freeze up and stop working
when metering these fluids. Eventually these cryogens
and subzero fluids freezes the internal measuring components
and your left with a rather large block of ice around
a non-functional Coriolis meter.
Just when the cyrogenic market was about to give up
on Coriolis technology, along comes RotaMASS with RCCS
sensors that can continuously handle fluid temperatures
down to -200°C. Here's how!
Specific materials are selected for the driver and
coil components inside the sensor. The electrical design
of these components also is critical to successful operation
in such difficult conditions. The interior space of
the RotaMASS sensor must always be kept free of any
air that could contain free moisture. But this is only
half the key to Yokogawa's success.
In measuring these fluids it important to maintain
their thermal inertia for reasons such as;
|- Fluid properties change dramatically
and affect the process performance
- Even the slightest warming can cause these fluid
to flash off, generating many vapour
bubbles and erroneous measurements.
So to maintain the fluid's thermal inertia, Yokogawa
provide as a standard factory option the following enclosure
of the RotaMASS sensor;
RotaMASS sensor and process heating is contained in
a two-part enclosure. Insulation wool is added to fill
The two halves are then riveted together.
The terminal box is extended beyond the exterior of
the enclosure to allow for field serviceability.
Liquefied Gas Applications
Below is an application of this technology on Liquid
Argon on Cryogenic Delivery tanker. Note the vertical
orientation of the RotaMASS sensor.
Note there is no thermal enclosure around this sensor
because the fill times are very short and there filling
is at a fixed rate.
For a more detailed analysis of your requirements
contact your local Yokogawa Australia Sales Engineer
This article has been contributed by Yokogawa Australia