Image Number 6 for United States Patent #4290271.
A flameless nitrogen liquid to gas converter for providing high pressure nitrogen as to treat oil and gas wells. A diesel engine prime mover drives hydraulic pumps and motors to pressurize nitrogen and actuate an air fan. Heat for converting the liquid nitrogen to gaseous nitrogen is obtained from the engine jacket water, the engine exhaust, and the hydraulic oil from the hydraulic pumps and motors. Additional heat can be obtained from the hydraulic oil system by increasing the hydraulic system pressure with a hydraulic pressure control valve. At least one of the hydraulic pumps and its driven hydraulic motor is in a hydraulic circuit which includes variable means for increasing the pressure in the hydraulic circuit, a hydraulic oil-air heat exchanger, and a hydraulic oil reservoir. Hydraulic fluid from the other pumps and motors is transmitted through the hydraulic oil-air heat exchanger. The system includes an in-line heat exchange system in series in the air flow from upstream to downstream in the following order: hydraulic oil-air heat exchanger, engine water-heat exchanger, engine exhaust-air heat exchanger, nitrogen-air heat exchanger, and an air suction fan.