Abstract: A liquid-vapor converter of a compact skid-mounted design is provided that efficiently converts a cryogenic liquid into a vapor, and which includes, in the same skid mounting, all necessary components necessary to receive the liquid and to provide therefrom a high pressure source of gas, particularly for use in recovery of product from oil wells. The design includes an internal combustion engine as a motive force to drive the main pump for pressurizing the vapor for its intended use. A heat exchanger receives the liquid and circulates the same through tubing, where the liquid is vaporized in the heat exchanger by ambient air being passed across the tubing to warm the liquid, thus effecting such vaporization. The heat exchanger utilizes heat from the engine exhaust to preheat the incoming ambient air prior to its passing in heat transfer relationship across the tubing.