Moisture insensitive microwave mass flow detector for particulate solids

Abstract

A novel moisture insensitive mass flow detector based on a mass flow sensor with open an cylindrical resonator is presented in this paper. The mass flow sensor consists of two MicroStrip Patch couplers integrated in a Composite Right-/Lefthanded Transmission line resonator. The design of a particulate mass flow detector based on this sensor is given and the algorithm to detect the average solids concentration is shown. The simultaneous detection of the velocity and the moisture independent solids/air concentration from a single measurement, ensures a true mass flow detector. Since it was already shown formerly, both sensor principles are able to measure the moisture dependent mass flow rate with high precision, we expect for the combination of both principles a detection accuracy in the range of both single sensor principles. Measurements of natural substance granulate with different amounts of moisture up to 18% (vol.) were done. The rearrangement of the CRLH-TL resonator to a helix shape opens the possibility to detect of the cross-sectional flow distribution of the fed material. Simulations and measurements of a helix shaped CRLH-TL resonator were done in order to proof the concept. The novel detector design is promising for industrial applications with various scenarios of gas/solids, gas/liquid and liquid/solids flows.

Non-Invasive Determination of the Mass Flow Rate for Particulate Solids Using Microwaves

“…For this, results obtained from an empty platform slid through the hose, as shown in Figure 9 , should be subtracted from the measurements. Wood pellets are prone to moisture absorption, and the unused modes of the sensor that are multiples of the resonance frequency could be utilized for precise moisture measurements, as shown in [ 18 ]. The sensitivity and detection limits of the sensor need to be further examined.…”