2 stage rotary compressor

Abstract

The present invention provides a 2 stage rotary compressor including a hermetic container ( 101 ), a 2 stage compression assembly provided in the hermetic container ( 101 ) and including a low pressure compression assembly ( 120 ), a middle plate ( 140 ) and a high pressure compression assembly ( 130 ), a low pressure refrigerant inflow portion ( 126 ) provided in the low pressure compression assembly ( 120 ) to introduce low pressure refrigerant, and a middle pressure refrigerant inflow portion ( 130 a ) provided in the high pressure compression assembly ( 130 ) to introduce middle pressure refrigerant compressed in the low pressure compression assembly ( 120 ), wherein a diameter of the middle pressure refrigerant inflow portion ( 130 a ) larger than 0.5 times of a diameter of the low pressure refrigerant inflow portion ( 126 ) and smaller than 1.1 times thereof. This configuration can prevent a pressure of middle pressure refrigerant sucked into the high pressure compression assembly ( 130 ) from being excessively raised or dropped by appropriately controlling a volume flow of refrigerant introduced into the high pressure compression assembly ( 130 ) through the middle pressure refrigerant inflow portion ( 130 a ).

1 . A 2 stage rotary compressor, comprising:
 a hermetic container;   a 2 stage compression assembly provided in the hermetic container and including a low pressure compression assembly, a middle plate and a high pressure compression assembly;   a low pressure refrigerant inflow portion provided in the low pressure compression assembly to introduce low pressure refrigerant; and   a middle pressure refrigerant inflow portion provided in the high pressure compression assembly to introduce middle pressure refrigerant compressed in the low pressure compression assembly,   wherein a diameter of the middle pressure refrigerant inflow portion is larger than 0.5 times of a diameter of the low pressure refrigerant inflow portion and smaller than 1.1 times thereof.   
     
     
         2 . The 2 stage rotary compressor of  claim 1 , wherein the diameter of the middle pressure refrigerant inflow portion is 0.6 times to 1.0 times of the diameter of the low pressure refrigerant inflow portion. 
     
     
         3 . The 2 stage rotary compressor of  claim 2 , wherein the diameter of the middle pressure refrigerant inflow portion is 0.9 times to 1.0 times of the diameter of the low pressure refrigerant inflow portion. 
     
     
         4 . The 2 stage rotary compressor of  claim 1 , wherein the low pressure compression assembly comprises a low pressure cylinder for supplying a space of compressing refrigerant, and the low pressure refrigerant inflow portion is a tube inserted to reach the refrigerant compression space of the low pressure cylinder. 
     
     
         5 . The 2 stage rotary compressor of  claim 1 , wherein the low pressure compression assembly comprises a low pressure cylinder for supplying a space of compressing refrigerant, and the low pressure refrigerant inflow portion comprises a hole formed in the low pressure cylinder and a tube inserted into the hole. 
     
     
         6 . The 2 stage rotary compressor of  claim 1 , further comprising a middle pressure passage for connecting the low pressure refrigerant inflow portion to the middle pressure refrigerant inflow portion. 
     
     
         7 . The 2 stage rotary compressor of  claim 6 , wherein the middle pressure passage is a U-shaped tube passing through the hermetic container. 
     
     
         8 . The 2 stage rotary compressor of  claim 6 , wherein the middle pressure passage is an inner passage defined inside the 2 stage compression assembly. 
     
     
         9 . The 2 stage rotary compressor of  claim 6 , further comprising an injection tube connected to the middle pressure passage. 
     
     
         10 . The 2 stage rotary compressor of  claim 6 , further comprising a middle pressure chamber positioned on the middle pressure passage. 
     
     
         11 . The 2 stage rotary compressor of  claim 10 , wherein the middle pressure chamber is defined by a bearing and a bearing cover. 
     
     
         12 . The 2 stage rotary compressor of  claim 10 , wherein the middle pressure chamber is positioned at any one of upper and lower portions of the 2 stage compression assembly.