| 摘要 |
A liquid dispensing nozzle is provided with a liquid discharge tube and a vapor recovery tube, both of which are adapted to be inserted into the fill pipe of a tank such as a motor vehicle gasoline tank. While gasoline or other volatile liquid is discharged through the discharge tube, a substantially equal volume of vapor is withdrawn through the vapor recovery tube to a pneumatic pump portion of a hydraulic motor-pneumatic pump device. Gasoline flowing through a hydraulic motor therein drives the pneumatic pump, which is operably connected to the hydraulic motor to be driven in synchrony therewith. The volume of vapor withdrawn from the fuel tank is adjusted to be approximately equal to the volume of liquid discharged, such that the pressure inside the tank is substantially atmospheric, and the end of the fill pipe of the tank may be sealed to prevent vapor from escaping or air from being drawn into the tank. The vapor recovery tube may be in communication with a vacuum chamber within the dispensing nozzle, such that blockage of the entrance end of the vapor recovery tube would result in a vacuum developed within the vacuum chamber sufficient to actuate a vacuum responsive device, which disables the manually operated lever of the dispensing nozzle.
|
