A pump body device comprises an external casing and is of the following structure: a volumetric component is arranged in the casing; the volumetric component comprises a volumetric piece and a bracket; one end of the bracket is connected with the casing through a fixing shaft, and the other end of the bracket is connected with the volumetric piece; the volumetric piece is shaped like a circular arc; the other end of the volumetric piece penetrates a component on the casing; and an opening for allowing liquid to flow in and out is formed in the casing. Through the structure, the invention provides an energy-saving and environment-friendly pump body structure with good energy-saving performance, small kinetic energy loss and low working noise, and solves the technical problem that a device in the prior art has high working noise and high energy consumption and is not beneficial to energy saving and environment protection.