Two-stage compression rotary compressor

Abstract

A two-stage compression rotary compressor is provided that includes a low-stage compressing section and a high-stage compressing section housed within a cylindrical sealed housing oriented vertically, a low-stage suction pipe that is connected to a suction side of the low-stage compressing section and sucks in a low-pressure refrigerant, a low-stage discharge pipe the is connected to a discharge side of the low-stage compressing section and discharges the refrigerant from the low-stage to outside of the sealed housing, a high-stage suction pipe that is connected to a suction side of the high-stage compressing section and sucks in the refrigerant discharged from the low-stage, a low-pressure connecting pipe that connects the low-stage suction pipe and an accumulator, and guides the refrigerant inside the accumulator to a suction side of a low-stage compressing section, and an intermediate connecting pipe that connects the low-stage discharge pipe and the high-stage suction pipe, wherein an inner diameter of the lower-stage connecting pipe is larger than an inner diameter of the intermediate connecting pipe.

1 . A two-stage compression rotary compressor comprising:
 a cylindrical sealed housing oriented vertically;   a low-stage compressing section provided on a low-stage and a high-stage compressing section provided on a high-stage housed within the sealed housing;   a motor that drives the low-stage compressing section and the high-stage compressing section housed within the sealed housing;   an accumulator disposed laterally to the sealed housing;   a first through-hole, a second through-hole, and a third through-hole provided in a sidewall of the sealed housing;   a low-stage suction pipe that is connected to a suction side of the low-stage compressing section via the second through-hole, and sucks in a low-pressure refrigerant;   a low-stage discharge pipe that is connected to a discharge side of the low-stage compressing section via the first through-hole, and discharges the refrigerant from the low-stage to outside of the sealed housing;   a high-stage suction pipe that is connected to a suction side of the high-stage compressing section via the third through-hole, and sucks in the refrigerant discharged from the low-stage;   a low-pressure connecting pipe that is connected to the low-stage suction pipe and the accumulator, and guides the refrigerant within the accumulator to the suction side of the low-stage compressing section; and   an intermediate connecting pipe that connects the low-stage discharge pipe and the high-stage suction pipe,   wherein a first inner diameter is larger than a second inner diameter, the first inner diameter being an inner diameter of the low-pressure connecting pipe and the second inner diameter being the inner diameter of the intermediate connecting pipe.   
   
   
       2 . The two-stage compression rotary compressor according to  claim 1 , wherein a first axial direction thickness is greater than a second axial direction thickness,
 the first axial direction thickness being an axial direction thickness of a low-stage cylinder that forms a part of the low-stage compressing section and is connected to the low-pressure connecting pipe via the low-stage suction pipe, and the second axial direction thickness being the axial direction thickness of a high-stage cylinder that forms a part of the high-stage compressing section and is connected intermediate connecting pipe via the high-stage suction pipe.   
   
   
       3 . The two-stage compression rotary compressor according to  claim 1 , equipped with a variable-speed motor system. 
   
   
       4 . The two-stage compression rotary compressor according to  claim 1 , wherein a suction unit that sucks in the refrigerant compressed to an intermediate pressure between a condensation pressure and an evaporation pressure of a refrigeration cycle is provided between the discharge side of the low-stage compressing section and the suction side of the high-stage compressing section.