Patent ID: 8206124

Claim:
An oil-gas tank vapor collection, storage, and recovery system in combination with an oil and liquid collection tank associated with gas and oil wells, the tank having a vent, a pressure vacuum release, and containing fluids therein, wherein the tank is connected to an inlet pipeline, the system comprising: a variable volume storage assembly wherein the assembly is a gas bag for the collection of headspace gas, the gas bag expanding when fluids are introduced into the collection tank, and the gas bag collapsing when fluids are removed from the collection tank and/or when the headspace gas in the gas bag is dispensed to a delivery pipeline; wherein the gas bag expands to a high position when the bag contains a high amount of headspace gas and collapses to a low position when the bag contains a low amount of headspace gas; a small gas engine having a gas engine throttle, wherein the engine uses a portion of the headspace gas for operation; a compressor driven by the gas engine to compress headspace gas into the delivery pipeline; at least one mechanical linkage between the gas bag and the engine throttle, wherein the linkage is either pressure-operated or electric-operated; and a control system comprising: a bag position indicator switch, wherein the indicator switch selectively moves the engine throttle into a high speed position when the bag is at the high position, whereby more headspace gas is compressed by the compressor into the delivery pipeline, and into a low speed position when the bag is at the low position, whereby less headspace gas is compressed by the compressor into the pipeline.