| 摘要 |
A beverage dispenser (10) includes a housing (12) for a pressurized beverage container, a flow meter (18) connected between the pressurized container and a faucet (22). A valve assembly (66,68,80) is attached to the faucet for opening and closing the faucet responsive to an electromechanical actuator (104,106,108). A programmable controller (30) in response to differential pressure indicating signals produced by the flow meter determines the flow rate incrementally and the incremental quantities are accumulated for comparison with a preselected programmed quantity for pouring a preselected quantity of the beverage and actuates the electromechanical actuator for the time necessary to pour the selected amount of beverage. The flow meter includes a line segment (111) of known length, size and material. The known length provides a measurable pressure difference owing to the drag therein as opposed to the measurable pressure difference obtained from the head of a manometer type flow meter. Thus, a substantially larger difference pressure measurement is obtainable. A differential pressure transducer (126) is connected to passageways (124,126) connected to line segment ports (128,130) located at beginning and ending points of the line segment for measuring the pressure differential and outputting electrical signs indicative thereof for use by the programmable controller in determining continuously during the pouring time the quantities for a preselected amount of the beverage. The valve assembly includes a valve stem sleeve (82) attached between the faucet end. The sleeve includes at the end adjacent to the faucet a seal expander (92) for wiping clean the portion of the valve stem (96) exposed to the beverage during valve opening. This prevents seepage of the beverage into the valve sleeve where it can solidify to stick the valve. |
