The MWS-DP-3 Microwave Solids Flow Sensor detects moving solids utilizing microwave high penetrability 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 analyzed as to whether they are from a moving or stationary object. The highly-penetrable microwave passes through a buildup on the head and even through pipe made of non-conducting materials such as plastics. The unit is best suited for detecting such materials as powders, granules, etc, moving through a vacuum pipeline.
When microwaves transmitted through the air encounter an object, some will be reflected, some absorbed and the rest will pass through the object. The amount of microwaves that pass through the object depends on the composition of the object encountered. Generally speaking, microwaves cannot penetrate metals and are reflected; water absorbs the most microwaves. Microwaves can easily pass through plastics, glass, ceramic, paper, etc. On the other hand, when microwaves are transmitted and reflected back to the sensor from a moving object, a frequency shift is generated between the transmitted and the reflected waves by means of the Doppler effect, which is converted to a motion signal and actuates an output relay.
– Easily penetrates process buildup on antenna, firebrick, refractory, etc.
– The sensor can be installed on the exterior of a plastic or ceramic pipe and detect the flow of material within the pipe.
– Mounted flush, no intrusion or damage to material flow.
EQUIPPED WITH A FILTER FOR SCREENING UNNECESSARY INCOMING DOPPLER SIGNALS:
– This function eliminates unnecessary incoming Doppler signals such as, signals from a vibrating pipe or conveyor.
– Improves the signal to noise ratio.
– This enables the sensor to be used in places where previously, non-contact 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 of the sensor.
– Allows for simplified maintenance of the sensor.
– The indicator clearly displays the advantage of the filter screening effect.
SELECTABLE DETECTION MODE:
– Either flow or non-flow detection mode may be selected.
EQUIPPED WITH A TEST BUTTON:
– LED indicators indicate microwave circuit status and internal temperature when the test button is pushed.
EQUIPPED WITH A DOPPLER SIGNAL INCOMING INDICATOR:
– An LED indicator turns on when the Doppler signal is received. Flow and non-flow conditions are clearly displayed.
The Blocked Chute Detection Application utilizes the WADECO MWS-DP-3 solids flow sensor and either the MWS-SR-11 receiver or the MWS-SR-2 receiver. In this case the MWS-DP-3 serves two purposes. First, it provides its normal function as a solids flow detector and second, it acts as a transmitter for the corresponding receiver. With this arrangement there will be two output signals. One will indicate the flow of material and the other will indicate whether or not the chute is obstructed. There are three possible conditions.
In this case the solid flow sensor will indicate that material is flowing past the sensor. The receiver may indicate blockage or no blockage depending on the position of the falling material.
Blocked Chute Condition:
In this situation the solid flow sensor would indicate the absence of flow and the receiver would indicate a blockage. This means the chute is blocked for some reason.
No Flow Condition:
In this scenario the solid flow sensor would indicate the absence of flow and the receiver would not indicate a blockage. This would mean that no material is entering the area being monitored.