Abstract: A mass flow meter includes a hollow base pipe having an inlet adapted to be attached to the discharge line of an air compressor or like apparatus to be tested. The base pipe also has an outlet end which is fitted with one of a plurality of convergent nozzles of differing, known throat diameters. A pressure gauge is fitted to the base pipe, upstream of the nozzle, to sense the pressure therein. The pressure gauge has ring-shaped mass flow rate indicia thereon which are individually calibrated to conform to each of the sized nozzles to permit direct reading of mass flow rates as a function of pressure.

Abstract: A method and apparatus for pneumatically conveying solid materials such as soil, stones and the like. A hollow bored tube having an inlet end, a discharge end and an intermediate injector section is provided with at least one nozzle of the converging/diverging type within the injector section. A compressor supplies air at a pressure of about 90 psig to the nozzle to create an air stream within the tube directed toward the discharge end thereof, at a velocity in the supersonic regime. A strong vacuum is thus created in the region of the inlet end to provide rapid evacuation of the solids into the tube for conveyance therethrough and ejection at the discharge end thereof.