Dry screw driver

Abstract

An embodiment of a dry screw compressor has a male rotor at a peripheral speed lower than approximately 80 m/s. The compressor includes: a casing body having an inlet for a gaseous fluid to be taken in and at least an outlet for the compressed fluid; at least a male rotor and at least a female rotor meshed together, said rotors being arranged inside said casing body whereby the ratio between the length and the external diameter of the male rotor is higher than or equal to approximately two, and the winding angle of the male rotor is smaller than or equal to approximately 300°.

1 . A dry screw compressor having a male rotor whose peripheral speed is lower than approximately 80 m/s, the compressor comprising:
 a casing body having an inlet for a gaseous fluid to be taken in and at least an outlet for the compressed fluid;   at least a male rotor and at least a female rotor meshed together, said rotors being arranged inside said casing body;   
       wherein the ratio between the length and the external diameter of the male rotor is higher than or equal to approximately two, and the winding angle of the male rotor is smaller than or equal to approximately 300°. 
     
     
         2 . The compressor according to  claim 1 , wherein the driving shaft is a shaft on which said female rotor is keyed. 
     
     
         3 . The compressor according to  claim 2 , further comprising an electric motor operationally acting on the shaft of the female rotor for starting its rotation around a first axis of rotation. 
     
     
         4 . The compressor according to  claim 3 , wherein in the rotor of said electric motor is keyed on said shaft of the female rotor. 
     
     
         5 . The compressor according to  claim 3 , wherein said electric motor is a permanent magnet motor. 
     
     
         6 . The compressor according to  1 , wherein said outlet defines an opening formed in the casing body, the actual size of said opening being variable by means of shaping means in order to obtain a predetermined compression ratio. 
     
     
         7 . The compressor according to  claim 1 , wherein the compressor can be used in applications under differential pressures approximately between 1 bar and 3 bars. 
     
     
         8 . The compressor according to  claim 1 , wherein the compressor can be used in applications under vacuum up to a threshold absolute pressure of approximately 150 mbars.