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June 2006 : SFD-2 and SFI



Microwave Non-Contact/Non-Invasive Solids Flow Detector Indicates Material Flow Problems

Elburn, IL -- The Model SFD-2 and SFI solids flow detectors use microwave technology to detect the flow and no-flow condition of powders and bulk solids as they discharge from bins and silos.  The SFD-2 and SFI can be used in in chutes, pipes and other conduits that these materials may flow through.  The sensor transmits microwave energy into a flow conduit and detects the material flow as the energy is reflected off the material.  The transceiver detects a Doppler shift in the microwave indicate material movement or flow.

Both units are easily installed and setup.  The use of microwave technology means that the transceiver can be mounted so that it is non-invasive into the flow stream and even non-contact if mounted on the outside of a non-metallic window or pipe/chute.  The Model SFD-2 provides relay contact closures in response to change sin flow and no-flow conditions.  The Model SFI provides an analog output.  When the SFD/SFI output is monitored, material stoppage (flow to no-flow) can be detected and flow-aid devices, such as aerators, vibrators or air cannons, can be initiated.

Monitor Technologies LLC is a leading supplier of level, flow, particle emission and aeration instrumentation for the worldwide powder and bulk solids market. The experience and market knowledge gained over five decades has earned Monitor a reputation for providing high quality and reliable product solutions.  Monitor is located in Elburn Illinois, give us a call today and let us put our creative solutions to work for you!



Spotlight: RF Capacitance Level Sensor
TrueCap Level SensorsTrueCap Light  
TrueCap® MK-2
Advanced RF Capacitance Level Probe

The TrueCap® Model MK-2 RF Capacitance point level probe is designed to provide a superior and stable sensitivity threshold making it suitable for a variety of powder / bulk solids and some liquid or slurry applications.

Advanced features of the Model MK-2 include:
> Automatic immunity to material build-up on the probe by its driven shield design
> Push-button calibration
> Enhanced temperature compensation
> Maximized reliability via smart sensing algorithms like “self-validating” fail-safe protection
> Visible status LED on ordinary location units
> Versatility through a variety of configuration options including: hazardous location version, split architecture design, quick-connect process connection, stub probe, cable extensions, solid extensions, Nylon® probes, Ryton® - equiv. probes, etc.

A practical application for the TrueCap would be to use this level sensor where a residual material build-up on a different sensor would cause a false material level indication.

Principle of Operation for the TrueCap RF Capacitance Level Probe:
The vessel wall and the active probe element establish an impedance reference between each other when exposed to air which has a dielectric constant of 1. When materials with a dielectric constant greater than 1 are in close proximity to the probe, the impedance of the sensing field between the sensor and the vessel wall will change. Once the amount of change exceeds a threshold that was electronically determined during the calibration process, an output relay will either be energized or de-energized depending upon the position of the fail-safe selector on the probe’s electronic circuit board. A change of as little as .5 pico-farad is all that is necessary for the probe to sense the presence of material.

Click here for more information on the TrueCap MK-2 Level Sensor or contact Monitor Technologies LLC at
Tel.: 800-766-6486 in the USA and
Tel.: 630-365-9403 worldwide.


>>Download TrueCap Product Bulletin #413

>>Click here to learn more about other Point Level Switches from Monitor Technologies


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