A hydrocarbon liquid-seal device is provided. The device includes first and second conduits in fluid communication with each other such that the first and second conduits define a flow path therethrough configured to pass a hydrocarbon vapor. The first and second conduits are in a spaced relationship and are not rigidly coupled to one another for isolating a vibration or movement respectively therein. The device further includes a liquid disposed within a space between first and second end portions of the first and second conduits, respectively, such that the liquid blocks the space between the first and second end portions and seals the hydrocarbon vapor in the flow path.