Two-stage pressurizer

The invention discloses a two-stage pressurizer. The two-stage pressurizer comprises a split type switching valve, a turbine shell exit piping, a gas compressor shell entrance piping, a split type check valve, a turbine, two turbine shafts, a bearing shell, a gas compressor impeller, a turbine shell, a gas compressor shell, a waste gas bypass valve and an actuator; a turbine shell separation strip separates the turbine shell into a low-speed turbine shell cavity and a high-speed turbine shell cavity; a gas compressor shell separation strip separates the gas compressor shell into a low-speed gas compressor cavity channel and a high-speed gas compressor cavity channel; the two turbine shafts are opposite in rotation direction, and the waste gas bypass valve is mounted on a turbine shell low-speed pressurizing waste gas entrance pipe. According to the two-stage pressurizer, the two turbine shafts rotate in opposite directions, and the turbine rotation directions of a low-speed pressurizing area and a high-speed pressurizing area are opposite; the gas compressor impeller rotation directions of the low-speed pressurizing area and the high-speed pressurizing area are opposite, so that the structure design arrangement of one integrated turbine shell, the gas compressor shell and one exhaust divided manifold is achieved, the space can be largely reduced, and the problem that an engine is inconvenient to arrange is solved; a waste gas bypass valve of the high-speed pressurizing area and a split type switching valve actuator are omitted, so that the manufacturing cost is reduced.