Structural features of vacuum pumps

(1) Overall structure type of pump
The layout structure of the pump body of the vacuum pump determines the overall structure of the pump.
The vertical structure has horizontal setting of the inlet and exhaust ports, and it is convenient to assemble and connect the pipeline. However, the center of gravity of the pump is high and the stability is poor at high speed, so this type is mostly used for small pumps.
The horizontal pump has an air intake on the top and a exhaust port on the bottom. Sometimes in order to facilitate the installation and connection of the vacuum system pipeline, the exhaust port can be connected from the horizontal direction, that is, the intake and exhaust directions are perpendicular to each other. At this time, the exhaust port can be opened from the left or right directions, except for one end of the exhaust pipe, the other end is blocked or connected to the bypass valve. This pump has a low center of gravity and good stability at high speeds. Generally, large and medium-sized pumps mostly use this structure.
The two rotor shafts of the pump are mounted perpendicular to the horizontal plane. This structure assembly gap is easy to control, the rotor assembly is convenient, and the pump occupies a small footprint. However, the center of gravity of the pump is high, the gear is inconvenient to disassemble and assemble, and the lubrication mechanism is relatively complicated.
(2) The transmission mode of the pump
The two rotors of the vacuum pump are relatively synchronized by a pair of high-precision gears. The drive shaft is connected to the motor by means of a coupling. There are two main types in the transmission structure arrangement: one is that the motor and the gear are placed on the same side of the rotor, as shown in the figure. The driven rotor is directly driven by the motor end gear, so that the torsional deformation of the active rotor shaft is small, and the gap between the two rotors will not be changed due to the large torsional deformation of the active shaft, so that the gap between the rotors is uniform during operation. The biggest disadvantage of this transmission method is: a. There are three bearings on the active shaft, which increases the difficulty of processing and assembly of the pump, and the disassembly and adjustment of the gear is also inconvenient; b. The overall structure is uneven, and the center of gravity of the pump is biased to the side of the motor and gearbox.