| 摘要 |
<p>A liquid dispensing system utilizes a microprocessor based electronic control and a positive displacement gear pump to accurately meter predetermined batches of liquid pumped from a supply tank. The gear pump is driven by a reversible motor through a gear reducer, and is operative to pump a predetermined fixed volume of liquid for each revolution or fraction of revolution of the pump drive shaft. A passive magnetic sensor is positioned adjacent the toothed periphery of a target wheel, which is mounted on the motor shaft, and generates a signal representative of the amount of rotation of the pump drive shaft. The electronic control is responsive to this signal for calculating the total volume of liquid dispaced by the pump. The electronic control includes a keyboard which enables a user to preprogram the precise amount of liquid to be dispensed. The system includes a discharge hose for dispensing the liquid into a user's container, which hose is automatically primed by the system prior to the dispensing operation. The system can also be provided with a provision to "drain back" the liquid into the supply tank after the dispensing operation, and/or to recirculate liquid through the supply tank when it is desired to mix the contents thereof.</p> |
