| 摘要 |
The invention relates to a level sensing and control system for regulating the high and low levels of a body of flowable solid material in a container or receiving tray, bin, tank or other receptacle. The system is applicable to loose solids in powdered, granular or other comminuted flowable form, and is particularly applicable to control the level of toner material utilized in electrostatic copying machines as in the illustrative embodiment disclosed herein. The system includes an open-ended vertical sensor tube disposed within the material container or receiver and which is connected intermediate its ends to a source of air or other pressure fluid which serves to trigger the system to cause automatic interruption of the material feed supply when a predetermined head of material is trapped in the tube, and to cause automatic operation of the material feed supply to replenish the material in the tray or receiver when the material level drops to a predetermined low level and allows the pressure fluid to freely escape from either or both ends of the sensor tube when the material reaches a predetermined low level. The positions of the opposite open ends of the sensor tube respectively define the high and low levels of the material deposited in the tray or receiver.
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