FEATURE FLOW, LEVEL AND CONTROL
Choosing the correct probe design and anticipating worst case conditions can minimise buildup of materials on GWR probes. Bob Botwinski of Magnetrol explains
Minimising buildup...
waveguide and is recommended for those difficult, low dielectric applications where sensitivity may be a concern. Magnetrol’s enlarged coaxial design can be installed directly into tanks as well as into side mounted chambers. It is specified for use in applications having a viscosity up to 2000 cP (mPa.s). The robust construction of the
enlarged coaxial GWR probe minimises handling/installation concerns. With more internal clearance, the enlarged design reduces the chance for buildup to occur. Magnetrol also provides an optional flushing connection that allows the user to purge the inside of the probe with water, steam, or any cleaning agent suitable for the application. This simple cleaning process can dissolve paraffin and grit without having to remove the probe from the vessel.
...on GWR probes
L
evel measurement applications in natural gas, condensate and
crude processing often have special requirements that are not always evident from instrument data sheets. The potential of solids or other materials building up on a Guided Wave Radar (GWR) probe is one example. Magnetrol has developed some
simple but effective level measurement techniques that address field issues such as process material buildup. Natural gas, condensate and crude
processing applications can experience paraffin, asphaltenes, grit and grime. Buildup in applications like this can occur over time or during cold weather periods when viscosity changes. The degree to which any of these items can affect GWR measurement varies by the application and specific probe type. These issues can often be overcome by simple maintenance schedules in which probes may require occasional cleaning. The most effective way to minimise
these issues is to anticipate worst case conditions and choose the proper GWR probe design.
COAXIAL GWR PROBE The coaxial probe is the most efficient
16 DECEMBER/JANUARY 2017 | INSTRUMENTATION
The latest GWR transmitters offer superior signal strength and
advanced diagnostics
CAGED GWR PROBES A single rod GWR probe can also be considered for these applications. Magnetrol offers a family of single rod probes designed specifically for use in 2” (DN50), 3” (DN80), and 4” (DN100) side mounted chambers. This probe design utilises the new or existing chamber as the second conductor to recreate the same signal propagation as a coaxial probe. The result is a probe containing the sensitivity and performance associated with coaxial probes, along with the buildup immunity of a single rod probe. The caged GWR probe is specified for use in applications with viscosities up to 10,000 cP (mPa.s). As with any single rod probe, it may need extra attention during installation. The caged GWR probe offers maximum clearance between conductors, which minimises the possibility of any buildup/bridging to occur. After the correct probe is chosen, the
installation itself needs to be considered. For example, effects from condensation or crystallisation can be eliminated by insulating or heat tracing the chamber. Also, chambers should be insulated even in warm weather locations – the temperature difference between a warm/hot vessel (like a separator) and uninsulated chamber/cages can be significant, resulting in paraffin deposition and/or viscosity increases. Similarly, chamber flanges should be insulated to reduce any cooling at the top of the probe.
THE TRANSMITTER The choice of the GWR transmitter itself can also be an important factor in both improving performance and reducing maintenance time. The latest GWR transmitters, like the Magnetrol Eclipse Model 706, offer superior signal strength, advanced diagnostics and additional features that can provide the user with proactive information. Signal to Noise Ratio (SNR) should be a significant factor to consider when choosing a GWR transmitter. SNR is critical to performance in difficult, low dielectric applications and opens up possibilities for utilising the caged single rod probe. Magnetrol’s Model 706 GWR transmitter offers a diagnostic capability with automatic waveform capture. Features such as buildup detection can be used and trended by the customer for planned, efficient maintenance scheduling.
OPTIMISING SUCCESS The key to optimising success in a GWR application consists of a number of factors, none more important than the other. Looking at the big picture is critical. Although cost always plays a factor in the decision for any level measurement application, care must be given to looking not only at the initial installation costs, but also the potential long term maintenance costs that can occur due to an unplanned shutdown caused by probe buildup. Customer experience can help
Optimising success in a GWR application consists of a number of factors, none more important than the other
with anticipating worst case process conditions. However, it is important to know that Magnetrol Technical Support can and should be leveraged to help with the proper probe choice and any other questions related to GWR technology itself.
Magnetrol
www.magnetrol.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
