| 摘要 |
An apparatus (50) and method for dispensing fluid material (55) from a dispensing gun (53) onto a workpiece (17) includes a metering cylinder (56) having a metering chamber formed therein with a pair of variable volume chamber portions (66,67), a valve assembly (52) connected to a supply of fluid material (51), the dispensing gun and to the chamber portions, and a control (58) connected to a meter actuator (60) connected to the metering cylinder and a valve actuator (59) connected to the valve assembly. The control (58) controls the meter actuator (60) and the valve actuator (59) in first and second modes of operation to dispense the fluid material (55) from the dispensing gun (53) by alternately drawing from the supply of fluid material (51) through the valve assembly into a first one of the chamber portions and forcing the fluid material from a second one of the chamber portions through the valve assembly to the dispensing gun. If the amount of material dispensed is less than the volume of the metering chamber, the control (58) controls the metering actuator (60) and the valve actuator (59) in a third mode of operation to force the fluid material in the metering cylinder (56) from one of the chamber portions into the other one of the chamber portions through the valve assembly (52) without forcing the fluid material from the valve assembly to the dispensing gun thereby resetting the dispensing apparatus.
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