On the basis of the single stage vacuum oil filter, the two-stage vacuum oil filter adds a Roots pump with high pumping speed, which can quickly and efficiently remove water vapor from the oil, greatly improving the drying degree, breakdown voltage value, and one-time filtration effect of the oil. This shortens the oil treatment period, thereby improving the performance of the oil. It can also vacuum the transformer and can be used at high altitudes.
Note: The working principle and performance characteristics of a Roots pump are essentially the same as those of a cam pump, but the rotor is of the Roots type. It can transport liquids with a viscosity of tens of thousands of centipoises. Roots pump mainly has two rotors with opposite rotation directions located in the pump body, driven by a pair of synchronous gears. For Roots pump rotors, they mesh with each other in the pump body, but have gaps. The size of the gap mainly depends on the viscosity of the liquid. If the viscosity exceeds a certain range, the gap must be adjusted and increased.
