Scroll fluid machine

Abstract

A scroll fluid machine comprises a stationary scroll fixed to a housing and an orbiting scroll that turns with a driving shaft. The stationary scroll comprises a stationary end plate having inner and outer stationary wraps and the orbiting scroll comprises an orbiting end plate having inner and outer orbiting wraps. Rotation of the orbiting scroll allows the inner and outer stationary wraps to engage with the inner and outer orbiting wraps respectively to form inner and outer volume-variable chambers. The two chambers have substantially the same compression ratio, so that substantially-equal low pressure gases are produced.

1 . A scroll fluid machine comprising: 
 a housing;    a driving shaft having an eccentric axial portion;    a stationary scroll fixed to and in the housing and having an inner stationary wrap and an outer stationary wrap on an stationary end plate; and    an orbiting scroll having an inner orbiting wrap and an outer orbiting wrap on an orbiting end plate, the orbiting scroll being revolved with the eccentric axial portion of the driving shaft with respect to the stationary scroll to allow the inner stationary wrap to engage with the inner orbiting wrap to form an inner volume-variable chamber within the inner stationary wrap and to allow the outer stationary wrap to engage with the outer orbiting wrap to form an outer volume-variable chamber between the inner and outer stationary wraps, the stationary end plate having an outer intake port at a circumference and an outer discharge port radially far from the circumference within the outer volume variable chamber and having an inner intake port radially far from a center and an inner discharge port at the center in the inner volume-variable chamber, the inner volume-variable chamber having substantially the same compression ratio as that of the outer volume-variable chamber, a gas introduced from the outer intake port being compressed in the outer volume-variable chamber with revolution of the orbiting scroll and discharged from the outer discharge port, a gas introduced from the inner intake port being compressed in the inner volume-variable chamber with the revolution of the orbiting scroll and discharged from the inner discharge port under substantially the same low-pressure as what is discharged from the outer discharge port.    
   
   
       2 . A scroll fluid machine as claimed in  claim 1  wherein the outer volume-variable chamber comprises an outer beginning-end volume-variable chamber communicating with the outer intake port and an outer terminating-end volume-variable chamber communicating with the outer discharger port, the inner volume-variable chamber comprising an inner beginning-end volume-variable chamber communicating with the inner intake port and an inner terminating-end volume-variable chamber communicating with the inner discharger port, a volume ratio of the outer terminating-end volume-variable chamber to the outer beginning-end volume-variable chamber being substantially equal to that of the inner terminating-end volume variable chamber to the inner beginning-end volume-variable chamber.  
   
   
       3 . A scroll fluid machine as claimed in claim I wherein the outer discharge port of the outer volume-variable chamber is connected to the inner intake port of the inner volume-variable chamber.  
   
   
       4 . A scroll fluid machine as claimed in  claim 1  wherein the scroll fluid machine is a scroll compressor.  
   
   
       5 . A scroll fluid machine comprising: 
 a housing;    a driving shaft having an eccentric axial portion;    a stationary scroll fixed to and in the housing and having an inner stationary wrap and an outer stationary wrap on an stationary end plate; and    an orbiting scroll having an inner orbiting wrap and an outer orbiting wrap on an orbiting end plate, the orbiting scroll being revolved with the eccentric axial portion of the driving shaft with respect to the stationary scroll to allow the inner stationary wrap to engage with the inner orbiting wrap to form an inner volume-variable chamber within the inner stationary wrap and to allow the outer stationary wrap to engage with the outer orbiting wrap to form an outer volume-variable chamber between the inner and outer stationary wraps, the stationary end plate having an outer intake port radially inward far from a circumference and an outer discharge port at the circumference within the outer volume variable chamber and having an inner intake port at the center and an inner discharge port radially far from a center in the inner volume-variable chamber, the inner volume-variable chamber having substantially the same compression ratio as that of the outer volume-variable chamber, a gas introduced from the inner intake port being decompressed in the outer volume-variable chamber with revolution of the orbiting scroll and discharged from the outer discharge port, a gas introduced from the outer intake port being decompressed in the inner volume-variable chamber with the revolution of the orbiting scroll and discharged from the outer discharge port under substantially the same low-pressure as what is discharged from the inner discharge port.    
   
   
       6 . A scroll fluid machine as claimed in  claim 5  wherein the outer volume-variable chamber comprises an outer beginning-end volume-variable chamber communicating with the outer intake port and an outer terminating-end volume-variable chamber communicating with the outer discharge port, the inner volume-variable chamber comprising an inner beginning-end volume-variable chamber communicating with the inner intake port and an inner terminating-end volume-variable chamber communicating with the inner discharger port, a volume ratio of the outer terminating-end volume-variable chamber to the outer beginning-end volume-variable chamber being substantially equal to that of the inner terminating-end volume variable chamber to the inner beginning-end volume-variable chamber.  
   
   
       7 . A scroll fluid machine as claimed in  claim 5  wherein the inner discharge port of the inner volume-variable chamber is connected to the outer intake port of the outer volume-variable chamber.  
   
   
       8 . A scroll fluid machine as claimed in  claim 5  wherein the scroll fluid machine is a scroll decompressor.