GB1475180A - Conveyor belt system with positional transformation of weight data - Google Patents

Abstract

1475180 Conveyer-belt weighing HYER INDUSTRIES Inc 18 Oct 1974 [21 Nov 1973] 45176/74 Heading G1N Position compensation apparatus for a conveyer belt comprises means for providing a first signal representing a characteristic of material on a portion of the belt when adjacent a first reference point; and means responsive to the first signal and to the belt motion to generate a train of pulses, each pulse representing a unit of weight of material on a belt portion adjacent a second reference point at the time of that pulse. A scale input sensor 52, for providing, e.g., a D.C. signal 52a proportional to the weight of material 21 on a unit length of a portion of a belt 12, is located at a first reference point 31 favourable to weighing accuracy, e.g. near the low-tension tail end 14 of the belt. An integrator 54, receiving the analogue weight signal 52a together with pulses 36a from a signal generator 36 representing units of belt travel, provides a train of pulses 30a, each pulse representing a unit of material weight passing the first point 31. The belt travel pulses 36a, which are arranged always to have more than twice the recurrence frequency of the weight pulses 30a, also gate a series of type D flip-flops SR-1, SR-2,... SR-D each constituting a stage of a shift register 42 and representing a unit increment of a distance L between the first point 31 and a second reference point 32 which may be the discharge end 16 of the belt. The repetition frequency of the pulses 40a emerging from the shift register 42 this represents the rate at which the material, accurately weighed as it passed the first reference point 31, is currently passing the second reference point 32. The apparatus may be coupled to a control subsystem, Fig. 3 (not shown), to enable material to be delivered at a predetermined rate or up to a predetermined quantity, or to blend materials in a predetermined ratio, Fig. 4 (not shown). The belt travel signal generator 36, Fig. 2, may be coupled to a tail-pulley shaft encoder at 22, or, if the belt is driven by a synchronous motor 18, may respond to the frequency of the A.C. supply. In a modification, (not shown), a suitable first weight signal may be fed directly into the shift register, the integrator then receiving the outputs of the shift register and of the belt signal generator, to convert them into the stream of mass-flow pulses.