Intercooler less air cooled 4 step roots die vacuum blower

摘要

PURPOSE: To dispense with an intercooler which has been required for each space between respective stages by parallel arranging plural compression chambers, and air-cooling a pump outer element by cooling fans on first and second rotor shafts. ;CONSTITUTION: A front first-stage compression chamber 7, a rear third-stage compression chamber 9, a front second stage compression chamber and a rear fourth stage compression chamber 10 are provided in a pump outer component 1, and Robots type rotors 11, 13 provided on a common shaft are accomodated in the first and third stage compression chambers 7, 9. Roots type rotors 12, 15 provided similarly on a common shaft are accomodated in the second and fourth stage compression chambers 8, 10. Pulleys 17, 18 integrated with cooling fans 19, 20, which are interlocked and driven by one motor, are fixed on the end parts of the respective rotor shafts 14, 16 that are projected from a housing. Passages 21-23 are provided to communicate between the first and second stage compression chambers 7, 8, between a discharge port 8b of the second stage compression chamber 8 and a suction port 9a of the third stage compression chamber 9, and between the third and fourth compression chambers 9, 10.;COPYRIGHT: (C)1995,JPO