JPS5462515A - Screw fluid machinery - Google Patents

Abstract

PURPOSE: To eliminate pressure pulsation and sharply reduce suction noise and discharge noise by making the number of teeth on two male rotors equal to each other, and shifting the phase of teeth, and making the lengths of intake passages equal to each other, and making the lengths of discharge passages equal to each other.

CONSTITUTION: When the male and female rotors revolve, as the phases of male rotors 14 and 14b are shifted by α = π/Z_m (π = ratio of the circumference of a circle to its diameter, Z_m = the number of teeth of the male rotor), the phases are nearly opposite to each other. As the sizes of two pairs of male and female rotors are equal, the amplitudes are equal, and the lengths of the intake passages 9a and 9b are equal, so the vibrations offset each other at an intake port 10, and the pressure pulsation in an intake pipe 25 is nearly eliminated, and also suction noise is eliminated. On the other hand, also the pressure pulsation in a discharge port 13 and a discharge pipe 26 is nearly eliminated. The thrust force between the male rotors 14a and 14b and the thrust force between the female rotors 15a and 15b offset each other.

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