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Flow/No-Flow and Blocked Chute Detection - Sensor Overview

Posted on 15/03/2021

The MWS-DP-3 Microwave Solids Flow Sensor detects moving solids by utilising highly penetrating microwaves and the Doppler effect.
The sensing head transmits microwaves toward the target material. A portion of the microwaves are reflected back to the sensing head and analysed as to whether they are from a moving or stationary object. The highly penetrable microwaves are able to pass through a buildup on the head and even through pipe made of non-conducting materials such as plastics. It is best suited for detecting such materials as powder, granules, etc, moving through a vacuum pipeline.

Special Features

Blocked Chute Detection

In addition to being used as a solids flow sensor, it can be used as a transmitter in combination with a receiver in order to detect a blocked chute.

Equipped With a Filter for Screening Unnecessary Incoming Doppler Signals.

This function eliminates unnecessary incoming Doppler signals such as the signals from a vibrating pipe or conveyor and improves the S/N ratio. This enables the sensor to be used in places where previously, non contract flow detection was hardly possible.

Equipped With a Sensitivity Margin Indicator

The received power level and the sensitivity set point are indicated on the sensor allowing for easy visual adjustment and maintenance of the sensor. The indicator clearly displays the advantage of the filter screening effect.

Application Examples

Flow/No Flow Detection

Thanks to the filter function, the solids flow sensor detects only the falling material without interference from conveyor 1 or 2, as can be seen here:

Flow/No Flow & Blocked Chute Detection

The receiver receives microwave beams from the solids flow sensor. When the beam is interrupted, the receiver will output a "blocked chute" signal. The operating distance between the Solids Flow Sensor and Receiver is up to 80 metres (standard type) but may vary from sensor to sensor and according to installation circumstances. When the MWS-SR-2 receiver is used for this application, its channel function cannot be used.

Installation Example

This is an actual application of the Solids Flow Sensor using the filter function

As you can see these sensors are perfect for blocked chute detection applications such as those in mining, food processing, recycling plants etc.

Semrad Pty Ltd is a leading Australian distributor of level switches and level transmitters, designed specifically for harsh industrial applications, including caustic and chemical solutions.

Semrad is dedicated to providing customers with the most cost effective and technically advanced solutions for the measurement and control of liquid and bulksolids level.
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