| 摘要 |
Two complimentary feeds are provided, the first from an alternate shuttle hopper feed employing a pair of volumetric metering cups provides a weight slightly less than the desired metered weight. The difference between the required metered weight and the short weight is scaled, determined and converted into an electrical analog signal. The second feed consists essentially of a hollow cylinder provided with a plurality of outwardly directed apertures asymmetrically arranged in longitudinal rows. Within the cylinder there is disposed a closed elastomeric tube, which when filled with air at low pressure will bear against the inner surface of the cylinder for ejection of material in said apertures. The feed cylinder is supported for rotation and coupled to an electrically controlled drive for selectable angular displacement thereof. Also included in a sensor for indicating electrically the angular position of the cylinder and whose output, with the analog short weight signal, are applied to an electronic control device which thereupon provides an output signal to said controlled drive to displace the cylinder a sufficient amount to dispense material, previously deposited in said recesses, to accurately compensate for the short weight. A vibratory feed supply is associated with the cylinder so as to provide a pellet for each aperture as it passes the feed point and a receptacle for receiving the pellets as they are gravity ejected.
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