Mechanical Booster Vacuum Pumps are used to evacuate gas from enclosed vessels and for maintaining the processing pressure. Figure 1 depicts a typical model. All pumps covered herein have 12-inch gear diameter and are equipped with either mechanical seals or slinger seals. The end sections are identical and the difference in CFM is the result of different lengths in the cylinder section and RPM.
The standard pump has slinger seals, horizontal gas flow, and the drive shaft connects to the upper drive gear. Mechanical seals on the rotor shafts and vertical gas flow are features which are available by special order. The pump is designed to rotate bidirectional and to establish the gas flow direction The pump is installed to rotate CW when furnished by Kinney Vacuum Company as a component of a pumping system. The pump has a water cooled module (mechanical seal housing) to prolong the life of the drive shaft mechanical seal. The heat exchanger is also water cooled.
An oil circulating pump, driven from the lower, free end, rotor shaft, provides positive oil lubrication throughout the pump as necessary. An oil filter is installed in the line between the circulating pump and the heat exchanger. Booster pumps consume greater amounts of power when discharging directly to atmosphere. Given enough power the pump will operate at high pressure but will overheat when pumping at inlet pressure less than approximately 360 torr. Boosters have a high volume capacity and typically operate in series with a backing pump to lower the pressure to the 50 torr range before starting. A pressure switch is commonly employed to start the Booster when the pressure is reduced to an acceptable starting pressure. |
