A Blockage Test or nitrogen testing is used in Vapor Recovery Systems to detect liquid in lower areas of piping systems, as this bottom loading station. Accumulated fluids can block the transfer of return vapor to a storage tank when dispensed with a balance stage recovery nozzle. A measured amount of Nitrogen gas is infused into the Vapor Recovery System and the amount of nitrogen that passes to the tank. If there is a difference between the amount of nitrogen that was sent down the line and the amount of nitrogen in the recovery tank then there is an impediment to vapor recovery or settled liquid in the pipelines.
Nitrogen testing is used to help detect blockages and leaks in oil pipelines so vapor recovery systems can work at optimum levels.
