Powdery-material feeding device

A powdery-material feeding device, comprising:

• a hopper configured to reserve a powdery material;
• a transfer member configured to deliver the powdery material to be discharged;
• a motor configured to drive the transfer member;
• and
• a controller configured to control the motor,
• wherein
• the controller selectively conducts
• constantly keeping-control of constantly keeping rotational speed of the motor, current or voltage applied to the motor without any change as a manipulated variable for a predetermined period even upon an increase or a decrease in discharge flow rate of the powdery material, or
• feedback-control of repetitively obtaining a difference between the discharge flow rate of the powdery material and a target value of the discharge flow rate of the powdery material at predetermined cycles and adjusting, by increasing or decreasing, the manipulated variable at each of the predetermined cycles in order to reduce the difference,
• the controller conducts the constantly keeping-control immediately after the hopper is filled with the powdery material,
• the controller shifts to the feedback-control when the difference between the discharge flow rate of the powdery material and the target value of the discharge flow rate of the powdery material has an absolute value less than a threshold after the period for the constantly keeping-control elapses, and
• the controller conducts constantly keeping-control again without shifting to the feedback-control when the absolute value of the difference between the discharge flow rate of the powdery material and the target value of the discharge flow rate of the powdery material is more than the threshold after the period for the constantly keeping-control elapses, and the manipulated variable during the repeated constantly keeping-control is changed in accordance with the difference between the discharge flow rate of the powdery material and the target value of the discharge flow rate of the powdery material after elapse of the period for latest constantly keeping-control.

A powdery-material feeding device, comprising:

• a transfer member configured to deliver a powdery material to be discharged;
• a motor configured to drive the transfer member;
• and
• a controller configured to control the motor,
• wherein
• the controller selectively conducts
• constantly keeping-control of constantly keeping rotational speed of the motor, current or voltage applied to the motor without any change as a manipulated variable for a predetermined period even upon a modification in discharge flow rate of the powdery material, or
• feedback-control of repetitively obtaining a difference between the discharge flow rate of the powdery material and a target value of the discharge flow rate of the powdery material at predetermined cycles and adjusting the manipulated variable at each of the predetermined cycles to reduce the difference,
• the controller conducts the constantly keeping-control after the motor starts,
• the controller shifts to the feedback-control when the difference between the discharge flow rate of the powdery material and the target value of the discharge flow rate of the powdery material has an absolute value less than a threshold after the period for the constantly keeping-control elapses.