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April 2004: Rotary Bin Monitor • SFD-2/SFI


Model KA
Proven Point Level
Bin Monitor

Elburn, IL - Monitor Technologies’ line of rotary paddle bin monitors are reliable, rugged and economical. They provide point level control for detection of dry bulk materials in a wide variety of applications. Monitor’s paddle units can be used to eliminate bin overflow, maintain a predetermined material level, indicate plugging of conveyors and pneumatic lines or provide any of a number of level control functions

Unlike many other available paddle units, Monitor’s rotary paddle level indicators incorporate a feature that automatically shuts off the motor of the unit when the paddle is in a stalled position, which both extends the life of the motor and minimizes maintenance. Monitor’s paddle units also have a built-in slip clutch to protect motor and drive gears from excessive forces and longer-lasting sealed bearings. Additionally, the paddle units’ new housing features a twist-on/off cover, 2 conduit entrances and is available with NEMA 4 and an explosion-proof ratings.

Because different material densities, particle sizes and flow characteristics require specific paddles for optimum performance, Monitor Technologies offers a variety of interchangeable paddle assemblies to fit most bulk solid application needs. Additionally, Monitor offers a high-temperature unit and an assortment of process connections and accessories.

Model SFD-2
Reliable Flow/No-Flow Detection

Elburn, IL - Utilizing excellent sensitivity and a non-intrusive housing design, Monitor Technologies’ Solids Flow Detector (SFD-2) and Solids Flow Indicator (SFI) provide a signal indicating the flow/no-flow condition of solids and powders in gravity chutes, feeders and pneumatic pipelines.

The SFD-2 and SFI use low-power microwaves to sense motion. Microwaves are virtually unaffected by heat, humidity, ambient light, pressure, vacuum, high or low temperatures, or dust. This gives the SFD-2 and SFI with maximum effectiveness in industrial applications. Both units also carry Hazardous Location Approvals.

The non-contact/non-intrusive design ensures long-term reliability and elimination of process contamination. Intrusive probes might wear out, break off or inhibit material flow. The ability to sense through most non-metallic surfaces allows the SFD-2 and SFI to have a non-intrusive flush mounting.

The selection of either SFD-2 or the SFI is based upon the type of output required (relay or analog). With convenient remote electronics, the SFD-2 provides relay outputs. The SFI has a variable analog signal relative to the magnitude of flow. This provides more information for the user than the “on-off” flow detection of the SFD-2.

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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