Ebara Corporation

Mitsuru Maeda

Kiyoshi Yanagisawa

Toshitsugu Sase

Michiaki Matsuda

Yoshiyuki Maruta

The present invention is drawn to a screw compressor having a wide operating range with respect to flow rate and pressure ratio, wherein a discharge opening portion of a casing is provided with a generally tapered notch portion so that compressed gas is gradually discharged from a certain fixed point where a volume ratio of one groove defined by rotors and the casing is smaller than an inherent built-in volume ratio. Since the present invention is arranged in the above-mentioned manner, the flow of the gas at the discharge opening portion is reduced by the notch portion which is readily formed. Thereby the variation range of the pressure (the amplitude of pulsation of the pressure) is decreased and the noise level is lowered. Further, a loss of pressure resulting from the rapid flow of the gas is restricted to thereby widen a range of preferable performance of the compressor.

Screw compressor

A muffler is constructed to have a tubular perforated plate within its cavity so as to divide the cavity into an outer resonant cavity and an inner resonant cavity, to thereby provide two resonant frequencies. The tubular perforated plate is formed in the shape of a funnel.

Growing community of inventors

Kanagawa, Japan

Mitsuru Maeda