| 摘要 |
The disclosure relates to improved methods of designing surfaces whereby to minimize the effects of changes in the coefficients of friction between so-called bulk fluids and the surfaces. The disclosure also relates to surfaces designed in accordance with the methods. A device embodying the invention, for metering the mass flow of bulk material, such as grain or other crop material, comprises a sensor member with a curved surface installed adjacent the outlet of a conveyor. The sensor member is mounted for pivoting about a transverse axis and is subject to a moment resulting from the material flow along its surface. A spring means is provided to keep the sensor member in zero load position. The displacement of the sensor member is proportional to the mass flow rate. Changing friction coefficients mu between the bulk material and the surface will affect the flow pattern therealong, but an array of length and/or inlet orientation angles can be found relative to which the measured moments remain substantially insensitive to these flow changes. Such metering devices may be used in grain and forage harvesters, wherein they need less recalibration under varying harvesting conditions.
|
