It is a kind of rotary intermittent cooking device,used in alkali or sulphate pulping technology, to cook wood chips,bamboo chips,straw,reed,cotton linter,cotton stalk, bagasse. The chemical and raw material can be mixed well in spherical digester, the output pulp will be good evenness, less water consumption, high consistency chemical agent, shorten cooking time, simple equipment, low investment, easy management and maintenance.