초록 ▼

In a method and a circuit for controlling an amount of pelletized material that is dispensed from a pellet dispenser, the dispenser is driven at the same speed during each one of a plurality of pellet dispensing cycles. The frequency of dispenser operation is varied by varying the time interval betw

In a method and a circuit for controlling an amount of pelletized material that is dispensed from a pellet dispenser, the dispenser is driven at the same speed during each one of a plurality of pellet dispensing cycles. The frequency of dispenser operation is varied by varying the time interval between pellet dispensing cycles. The circuit includes two timers, an OFF timer which is connected to a counter that counts the number of “off”timing signals in each “off”period and an ON timer that receives a triggering signal from the counter when the “off”period is completed. A switch is connected to the counter to select this number of “off”timing signals. The “off”time period can also be altered by altering the time base of the OFF timer. This is accomplished with a resistance circuit that is connected to a timing circuit for the OFF timer, through either a user-controlled timer or a temperature-responsive switch.

대표청구항 ▼

Apparatus for selecting one of a plurality of constant rates at which dry chemical is emitted from a dispenser over a treatment period that includes a plurality of dispensing cycles, the apparatus comprising: drive means for driving the dispenser at the same speed during each dispensing cycle; switc

Apparatus for selecting one of a plurality of constant rates at which dry chemical is emitted from a dispenser over a treatment period that includes a plurality of dispensing cycles, the apparatus comprising: drive means for driving the dispenser at the same speed during each dispensing cycle; switch means for turning the drive means on and off; means for generating first triggering signals; first timer means responsive to the first triggering signals to generate sequences of first timing signals during respective “off”periods for the dispenser; counter means for receiving and relating the sequences of first timing signals to respective second triggering signals according to a user-selected count that determines the duration of each “off”period and a selected constant rate of dispensing cycles; second timer means responsive to the second triggering signals to generate corresponding second timing signals to the switch means to cause the driving of the dispenser for respective dispensing cycles, the second timer means being further responsive at the end of each dispensing cycle to signal the first timer means to start generating a next sequence of first timing signals for a next “off”period.