Features: 

Microwave Solids Flow Monitors - Models SFD-2 & SFI
- Senses Light And Heavy Materials, Small And Large Particles
- Non-Contact Sensor Detects Flow Through Most Non-Metallic Surfaces 
- Non-Intrusive Flush Mounting. No Probe Protruding Into Material Flow
- SFD-2 Provides Relay Outputs and Convenient Remote Electronics
- SFI Solids Flow Indicator Provides Variable Analog Signal
- Sensors Include CSA Class II, Division I Approval for Hazardous Locations 

Applications  
Monitor's Solids Flow Detector and Indicator can be used in a variety of applications to detect flow/no-flow conditions of powders and solid materials. The selection of either SFD-2 Solids Flow Detector or the SFI Solids Flow Indicator is based upon the type of output required (relay or analog).
- Detection of a partial or full plug in a conveying line
- Detecting the bridging of material in a storage vessel upstream
- Sensing inadequate or a lack of flow due to upstream equipment failure (conveyor, blower, diverter valve, feeder)
- Verifying flow conditions
- Turning on/off equipment or processes downstream

Principle of Operation  
Both the SFD-2 and SFI utilize a microwave transceiver (combination transmitter/receiver) enclosed within a watertight, dust-ignition proof powder coated aluminum housing with a screw-on/off cover. A process seal (Teflon® or Ryton®) acts as a transparent window through which the microwave energy is transmitted and the reflected return signal is received. The transceiver module generates and transmits a microwave signal into the area where material flow is to be monitored. The reflected microwave signal shifts in accordance with the Doppler Effect phenomena. The Doppler-shifted energy is analyzed to determine the appropriate output from the unit. The SFD-2 has a split-architecture design consisting of the transceiver and a separate power supply/conditioning circuit board. The relays are incorporated on the power supply/conditioning circuit board, which is optionally available with a fiberglass enclosure and indicating lights. With the SFD-2, the Doppler-shifted energy signal from the transceiver is carried back to the power supply/conditioning circuit board through the user-supplied signal and power supply cable. At the power supply/conditioning circuit board the signal intensity is indicated with an LED and converted into a relay output based upon the sensitivity adjustment. The power supply/conditioning circuit board provides the power to drive the transceiver and contains the controls for setting sensitivity, hold-off time delay, hold-on time delay and fail-safe selection. The SFI Solids Flow Indicator, unlike the SFD-2, consists solely of a transceiver. In this case the transceiver will receive its DC power through the user supplied signal cable and power supply. The three-wire design allows the user to monitor the analog output while providing the supply power to the unit. The Doppler-shifted energy is relative to the magnitude of the flow/no-flow condition that exists, when material velocity is constant, and this is reflected in the varying analog output signal.