Vacuum pump assembly with improved process by-product holding capacity

A vacuum pump assembly with an improved process by-product holding capacity, comprising:

• a front bearing plate, an upper casing, a lower casing, a long rotor, a short rotor, and a rear bearing plate;
• wherein
• the long rotor and the short rotor rotate about their respective rotary shafts in opposing directions, axes of the rotary shafts of the long rotor and the short rotor being set parallel to each other;
• the long rotor and the short rotor each comprise multiple stages of rotor elements, the plurality of rotor elements being arrayed at intervals in respective axial directions of the rotary shafts of the long rotor and the short rotor;
• the multiple stages of rotor elements of the long rotor and the multiple stages of rotor elements of the short rotor mesh with one another correspondingly, storage grooves being set on non-critical surfaces of the rotor elements when meshing with one another;
• the non-critical surfaces of the rotor elements are portions of each of the multiple stages of rotor elements which do not form a seal with inner sidewalls of the upper casing and the lower casing and portions other than blade peaks and blade valleys of the rotor elements, and wherein
• a plurality of storage grooves are arranged on the long rotor, one end of each of the storage groves on the long rotor communicating with an end surface of the long rotor facing a gas intake direction, another end thereof not communicating with an end surface of the long rotor facing a gas exhaust direction, or
• a plurality of storage grooves are arranged on the short rotor, one end of each of the storage grooves on the short rotor not communicating with an end surface of the short rotor facing the gas intake direction, another end thereof communicating with an end surface of the short rotor facing the gas exhaust direction.