초록 ▼

An improved two feeder tray bulk weighment control system of the vernier operating type is disclosed. During an initial portion of the operating cycle of the device and while the weighment from the previous cycle is being dumped, a first feeder tray is driven to deliver a preliminary bulk target of

An improved two feeder tray bulk weighment control system of the vernier operating type is disclosed. During an initial portion of the operating cycle of the device and while the weighment from the previous cycle is being dumped, a first feeder tray is driven to deliver a preliminary bulk target of 80-98% of the desired final weighment into a second feeder tray. During the conveying portion of the operating cycle both trays are driven at a rate inversely proportional to the difference between the actual weighment and a target weighment signal in an underdamped manner. As the final weighment is approached, improved circuitry prevents scale overshoot due to the underdamped rate controllers from causing premature dumping. A servo loop is also provided to cause the feed controller in operation during the dumping portion of the operating cycle to deliver the 80-98% of desired final weighment based on its actual delivery on the previous cycle of operation.

대표청구항 ▼

Apparatus for repetitively weighing and dumping preselected weight of a bulk granular product in a weigh and dump cycle having a weigh portion and a dump portion comprising: first product feeder tray means of the vibratory type for delivering an output of product at a rate proportional to its speed

Apparatus for repetitively weighing and dumping preselected weight of a bulk granular product in a weigh and dump cycle having a weigh portion and a dump portion comprising: first product feeder tray means of the vibratory type for delivering an output of product at a rate proportional to its speed of vibration; means for delivering product under gravity flow into said first feeder tray; second product feeder tray means of the vibratory type arranged to receive the output of said first feeder for delivering an output of product at a rate proportional to its speed of vibration; weigh and dump bucket and scale means, arranged to receive the output of said second feeder tray means, for weighing the product so received and for generating an underdamped output signal representative thereof; means for, during said weigh portion of said weigh and dump cycle, controlling the vibratory rates of said first and second feeder means in an underdamped manner in response to the difference between said output signal and a preselected target weighment signal; means for, during said dump portion of said weigh and dump cycle, controlling the vibratory rate of said first feeder means only, in response to a bulk weighment representative output signal derived at an arbitrary time in the previous weigh cycle and functionally representative of a bulk weighment delivered from said first feeder means to said second feeder means during the previous dump portion of said weigh and dump cycle; and control means responsive to said output signal for detecting when a predetermined amount of produce is delivered from said second feeder means to said weigh and dump bucket means and for initiating said dump portion of said weigh and dump cycle upon such occurrence.