Buffer and gas circuit applying same

According to the technical scheme, the buffer is characterized in that the buffer comprises a buffer air cavity, and the buffer air cavity is composed of a first area and a second area; the first area is arranged in a conical shape; the second area is in smooth transition from the large-diameter section of the first area, the inner surface of the second area is smooth, and the curvature is slowly and smoothly reduced from the end, close to the first area, of the second area to the end away from the first area; the pressure of gas flowing into the buffer gas cavity is suddenly reduced when the gas enters the buffer gas cavity through the first area, part of kinetic energy of the gas is converted into static pressure energy, the flow speed is reduced, and the gas flows through the second area with the curvature gradually reduced in the backward flowing process. The buffering effect of the buffering air cavity is improved while the size of the buffering air cavity is not changed, and therefore impact airflow pos