Vacuum bottle with replaceable single-layer middle-section large-head cap

The utility model discloses a single-layer middle-section large-head cap replaceable vacuum bottle which comprises an outer bottle, an inner bottle arranged in the outer bottle, a middle section arranged at a bottle opening of the outer bottle, a piston arranged in the inner bottle and a pump body assembly arranged at a bottle opening of the inner bottle and partially located in the middle section, and an air hole is formed in the bottom of the inner bottle. The pump body assembly comprises a middle ring, a pump core arranged in the middle ring in a sleeved mode and a head cap arranged on the pump core, a plurality of limiting pieces are arranged on the inner wall of the middle section, limiting grooves are formed below the limiting pieces, and a plurality of stopping pieces used in cooperation with the limiting grooves are arranged on the outer wall of the end, away from the head cap, of the middle ring. The middle section and the pump body assembly (middle ring) are in detachable connection through matching