Abstract: A degassing system for a hydrocarbon dispenser including a hydrocarbon circulating pump (12). The system includes a degassing assembly (16) having an inlet connected to the outlet of the pump, a degassed hydrocarbon outlet (90), a takeoff outlet (20) for taking off the hydrocarbon/gas mixture, a degassing vessel (24), and a duct (38, 60") for connecting the takeoff outlet to the degassing vessel. The end of the duct which opens out into the degassing vessel has an adjustable effective flow section. The system also includes a valve arrangement (110, 118) for modifying the effective flow section as a function of the gas content of the hydrocarbon.

Abstract: A metering system, for metering a volume V.sub.o of compressed gas supplied under high pressure from a first tank to a second tank, includes a first duct for supplying the compressed gas from the first tank to the second tank, the first duct having a pressure regulator providing a relatively high driving pressure P, and a first nozzle having a section S with an inner diameter located downstream of the pressure regulator and providing a downstream pressure p therefrom, the pressure regulator being controlled by the downstream pressure p to maintain driving pressure P so that the downstream pressure p remains less than 0.95 P. A second duct branches at one end from the first duct between the pressure regulator and the first nozzle and includes a second nozzle having a section s with an inner diameter smaller than the inner diameter of the section S of the first nozzle.

Abstract: The efficiency of hydrocarbon vapor recovery installations used in gas stations is measured. A system for measuring a yield of recovery for hydrocarbon vapors emitted from the tank of a vehicle as it is being filled comprises at least one box for carrying a nozzle inside and for placement over a filler neck of the tank. The nozzle is connected through a conduit to a device for evaluating the recovered hydrocarbon vapor, wherein the recovered vapor evaluation device is a gas meter and a following orifice.

Abstract: A tubular device is slid over a delivery nozzle hose. A hose connects the tubular device to a gas meter. As fluid is expelled from the nozzle into the atmosphere, atmospheric air is sucked into the gas meter so that its volume can be measured for comparison with the volume of the expelled fluid.

Abstract: A positive-displacement fluid flow measuring system, especially for hydrocarbon fuel dispensers. The measuring system comprises, in addition to a positive-displacement meter per se, a correction system for correcting the loss of head in the meter. The correction system comprises a differential pressure detector responsive to the difference between the pressures at the inlet and the outlet of the meter. The displacement of the membrane enables an external motor to be coupled to the shaft of the meter by means of the plates.