SILO PATROL® SE INVENTORY MONITORING SYSTEM

Flexar® Guided Wave Radar Level Sensor

When All The Pieces Fit Just Right!
The Flexar^® continuous level measurement system is a smart guided wave radar device used for monitoring the level of powders, granules and other bulk solids. It is also suitable for use with a variety of liquids and some sluries. It is used in a wide assortment of vessels and industries for measuring levels up to 200ft (60m) in height.

Bringing the Pieces Together: Manufactured at our facility in Elburn, IL, we uniquely combine this proven and strategically acquired technology with almost five decades of expertise and focus in powder and bulk solids applications, and with our SiloTrack™inventory management software interface. Monitor Technologies uniquely provides the best solutions in level measurement and inventory management of powders and bulk solids.

The Flexar guided wave radar level sensor and/or transmitter requires no field calibration or re-calibration and can be setup easily by customer personnel without the use of any special tools or training. Flexar units are suited for almost any application, can operate with process temperatures up to 392° F (200°C), can be provided with a variety of process connections and can work reliably with materials having a wide range of bulk densities and dielectric constants.

Flexar is available with a choice of two outputs. The standard output is a “smart” interface for use with SiloTrack™ Version 3.5 PC-based inventory management software. This network-ready software provides a flexible graphical interface for up to 128 “smart” output sensors. In lieu of this “smart” output, an optional analog output is also available.

Principle of Operation

Flexar^® smart guided wave radar level sensors and transmitters operate using TDR (time domain reflectometry) principles that were first developed in the middle part of the 20th century for use in the geological field. Further development of TDR led to its use in the telecommunication industry for detecting breaks in cables. Flexartechnology was pioneered in the mid-late 1990’s when TDR was applied to level measuring applications within the process measurement industry.

In the application of TDR for process level measurement micro-pulses are continuously transmitted along a probe or “wave guide” at the speed of light. As soon as the pulses reach the material surface they reflect back to the sensor electronics unit. The time-of-flight of the pulses is calculated and directly related to the distance from the point at which the sensor is mounted on the top of the vessel to the material surface (level). The output from the electronics is continuously updated as the level of the material surface changes.

Flexar smart guided wave radar sensors are equipped with two different measuring modes. In the Direct measuring mode the pulses directly reflect off the material surface back to the electronics unit. This mode is used in applications where the material being measured has a dielectric constant as low as 2.1 for single-cable/rod probes and 1.8 for twin-cable probes.

For materials with dielectric constant below the above mentioned limits, down to as low as 1.4, the second measurement mode is used. This is the TBF (tank bottom following) mode, which is used due to the inability of the pulses to adequately reflect off of the surface of very low dielectric materials. In this measuring mode theFlexar sensor has a “short circuit” at the bottom of the probe at a precisely known distance from the sensor’s mounting point.

In the TBF mode the pulses travel through air at the speed of light and then pass through the material in the vessel at a slower speed, dependent on the specific dielectric constant. The pulses are reflected at the short circuit back up the probe. Flexarsensors in the TBF mode measure the time between the emission and reception of the pulses from the probe short circuit. Because the return time of a pulse when no material is present (through air) is known, we can determine the difference in time between the time-of-flight when empty and the time-of-flight when filled as being directly proportional to the material level in the vessel.

Applications

(click here to download - Solids App)

(click here to download - Liquids App)

The Flexar® smart guided wave radar continuous level measuring system can be used in a wide variety of applications, including powders, coarse/fine granular solids, liquids, foodstuffs and even some corrosive substances. Flexar sensor technology is proven in many difficult applications including those where dust levels make it difficult for other technologies to perform reliably, especially at long ranges. 

The maximum range for solids applications is limited to 100ft (30m) due to load limits possible from heavy materials in long ranges. Liquid applications can extend up to 200ft (60m). Any application requiring a continuous level measurement update where the process temperature does not exceed 392° F (200°C) and 580psig (40bar) is possible. The 316 stainless steel probes and threaded or flanged process connections make the Flexarcontinuous level measuring system ideal for almost any bulk solid and liquid application. To ensure a successful and reliable application, consult with the Monitor Technologies factory-based technical support group to see if Flexar is right for your application.

Remote Inventory Monitoring

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