Measuring challenging media

Paul Boughton

Bob Botwinski looks at using advanced guided wave radar for level measurement and control.

Guided wave radar (GWR) offers users a unique solution to measure and control challenging media and process variations. Magnetrol pioneered GWR by introducing the ECLIPSE Model 705 two-wire, loop-powered transmitter for use in industrial liquid level applications. Over the course of the past decade, Magnetrol the first high-temperature, high-pressure probe; the first patented steam probe; the first interface transmitter; culminating in the incorporation of GWR into a patented Aurora MLI chamber to offer true redundant measurement. Now, Magnetrol is introducing the next generation of GWR transmitter with the release of the ECLIPSE Model 706.

The ECLIPSE Model 706 transmitter has taken GWR to the next level with a strong, accurate signal technology, powerful diagnostics and an extensive probe offering designed to meet the special demands of temperature, pressure, viscosity, liquid interface, extended ranges and other variables. From hydrocarbons to water-based media, the ECLIPSE Model 706 accurately measures top level and interface liquids, slurries, and bulk solids with a dielectric range from 1.2 to 100. The Model 706 performs in all conventional process and storage vessels, bridles, and bypass chambers whose temperatures and pressures are rated to the capabilities of the particular probe used. ECLIPSE is at work in the most demanding applications, including those in petroleum refining, electric power generation, chemical manufacturing, water and wastewater, pulp and paper, food and beverage, and pharmaceutical processing.

High performance, low power

Incorporating GWR technology, ECLIPSE measurement performance is not process-dependent; therefore, varying specific gravity or dielectric constant have little or no effect on measurement accuracy. The ECLIPSE Model 706 utilises many special-purpose probes, including those having high-temperature (to +850°F/454°C), high-pressure (to 6250psig/430bar), ultra-low dielectric ([s40]1.2) and bulk solids probes with 3000lb. pull-down capability. Flexible probes with an extended measuring range up to 30 metres (100 feet) can be utilised.

Even though the ECLIPSE Model 706 has one of the strongest transmitted GWR signals on the market, a far more important parameter in reliable level measurement in difficult applications is the overall signal-to-noise ratio (SNR). Breakthrough innovation in the transmitter GWR circuitry allows the Model 706 to achieve both a higher transmit pulse amplitude and improved receiver sensitivity, resulting in superior SNS ratio as compared to competitive GWR devices. This reduction in system noise, coupled with a stronger transmit signal, results in a SNR that is up to 3 times higher than the nearest competitor. This simply makes the ECLIPSE Model 706 more robust, even in those difficult, low dielectric applications.

Another feature to the ECLIPSE Model 706 transmitter is the Overfill Capability of many of the probes in its offering. An Overfill Safe probe is one defined by the fact that it has predictable and uniform characteristic impedance all the way down the entire length of the waveguide (probe). These probes allow the ECLIPSE Model 706 to measure accurate levels to within specification up to the process flange without any non-measureable zones at the top of the GWR probe. Overfill Safe GWR Coaxial and Caged Probes can be installed in various configurations, even when the risk of flooding exists.

The ECLIPSE Model 706 takes the user interface experience to new levels of convenience and functionality. The LCD diagnostics convey critical real-time waveform and trend data with outstanding ease of use. The transmitter can be configured to automatically capture troubleshooting waveforms based on diagnostic events or based on time. The ECLIPSE Model 706 can also be preconfigured prior to shipment, to ensure plug-and-play transmitter commissioning.

Bob Botwinski is the Guided Wave Radar Product Manager at Magnetrol Inc, Illinois, USA.