Foreign on-line monitoring of gasoline recycling is very strict, recycling equipment, quality supervision is also very harsh. The United States Environmental Protection Agency (EPA) on the installation of oil and gas recovery and treatment plant gas station carried out a detection study found that the average recovery efficiency of oil and gas recovery system is only about 60%.

According to the results of the analysis, it can be seen that the oil and gas recovery efficiency is 24% due to the failure of A / L failure, the oil pressure is too high, the oil and gas leakage is discharged, the recovery efficiency is 29%, the oil tank or oil pipeline Leakage caused by oil and gas leakage recovery efficiency of 34%.

EPA believes that only the completion of the gas station oil and gas recovery and reconstruction is not yet able to fundamentally solve the problem of oil and gas leaks at the gas station, the need for on-line monitoring means, the oil and gas recovery system for long-term, continuous monitoring, based on monitoring results on substandard processing unit To repair the oil in order to effectively ensure the operation of oil and gas recovery system and oil and gas recovery efficiency.

At present, the commercialization of oil and gas recovery on-line monitoring equipment to foreign products, the United States Veeder-Root's ISD system, Germany FAFNIR VAPORIX system. US Veder-Root ISD system is the only through the United States CARB certified gas station oil and gas online monitoring equipment, by Roots flowmeter, pressure sensor, ISD memory expansion card and ISD interface module and other components, its working principle is the flow meter and Pressure sensor to send data to the tanker TLS console, while collecting fuel pulse signal, calculate the A / L; Roots flow meter can automatically compensate for the pressure and temperature changes caused by the error; with abnormal working status alarm and forced lock Tanker function, urge the gas station management personnel to repair the fault, to maintain stable operation of the system.