Experimental assessment of application of gravimetric measurements for pneumatic conveying in horizontal pipelines

Available theoretical considerations and practical experiments usually concern aspiration in the vertical pipelines, where the procedure of making measurements is universally known and it does not express any reservations. However, it is often necessary to conduct test in the systems of horizontal conveying of solgas, where the conditions of taking a representative sample, even for the sake of the significant effect of the gravitational force, many vary from those suggested for measurements in the systems with vertical flow. The present paper contains the results of tests which determine usability of the gravimetric method in measurements of flow parameters of two-phase gas-solid mixture in a horizontal pipeline. The tests were performed in the test stand, by use the mixture of air and shale coal. Dust samples were quantitatively analyzed by means of a grain-size laser analyzer. The relative measuring error was determined and related to a change of flow parameters. Possibilities of limitation of errors of the measuring method were discussed. The main conclusion of experiment is that the gravimetric measurements in horizontal pipes can be applied only for homogeneous or quasi-homogeneous distribution of concentration and velocity of horizontal flow of solgas.