Screw compressor

Abstract

In order to obtain a screw compressor which is small in size and weight and has ease of maintenance and high reliability, the screw compressor comprises a screw rotor, a low-pressure-side bearing and a high-pressure-side bearing which support the screw rotor, a motor which drives the screw rotor, a motor casing which accommodates the motor, a main casing which accommodates the screw rotor and the low-pressure-side bearing, and a discharge casing which accommodates the high-pressure-side bearing. The motor casing, the main casing, and the discharge casing are accommodated in a steel pipe chamber, and the steel pipe chamber includes a low-pressure-side chamber and a high-pressure-side chamber which are able to be divided in the axial direction. By using a flange provided on an inner surface of the steel pipe chamber, a flange provided in the main casing, and a sealing component provided between the flanges, the steel pipe chamber is divided into a low-pressure-side space and a high-pressure-side space.

1 . A screw compressor comprising:
 a screw rotor which includes a toothed portion and a shaft portion;   a low-pressure-side bearing and a high-pressure-side bearing which support the shaft portion of said screw rotor;   a driving motor which is directly connected to the shaft portion of said screw rotor;   a motor casing which accommodates the motor;   a main casing which accommodates said screw rotor and said low-pressure-side bearing;   a discharge casing which accommodates the high-pressure-side bearing of said screw rotor; and   a steel pipe chamber which accommodates said motor casing, said main casing and said discharge casing,   wherein said steel pipe chamber includes a low-pressure-side chamber and a high-pressure-side chamber which are able to be divided in an axial direction, and   wherein a space inside said steel pipe chamber is divided into a low-pressure-side space and a high-pressure-side space through a flange provided in an inner surface of the steel pipe chamber, a flange provided in said main casing or said motor casing, and a sealing component provided between said flanges.   
     
     
         2 . The screw compressor according to  claim 1 ,
 wherein said low-pressure-side chamber and said high-pressure-side chamber are connected to each other through flanges provided in outer-surface ends thereof, so that the inside of the steel pipe chamber is sealed from an ambient air.   
     
     
         3 . The screw compressor according to  claim 2 ,
 wherein said high-pressure-side chamber is divided into two parts in the axial direction so as to form a first high-pressure-side chamber connected to said low-pressure-side chamber and a second high-pressure-side chamber connected to the first high-pressure-side chamber, and   wherein the first and second high-pressure-side chambers are connected to each other through flanges provided in outer-surface ends thereof, so that the inside of the steel pipe chamber is sealed from the ambient air.   
     
     
         4 . The screw compressor according to  claim 1 ,
 wherein said flange provided on the inner surface of said high-pressure-side chamber is connected to said flange provided in said main casing through said sealing component, so that a space inside the steel pipe chamber is divided into a low-pressure-side space and a high-pressure-side space.   
     
     
         5 . The screw compressor according to  claim 1 ,
 wherein said flange provided on the inner surface of said high-pressure-side chamber is connected to said flange provided in said motor casing through said sealing component, so that said space inside said steel pipe chamber is divided into the low-pressure-side space and the high-pressure-side space.   
     
     
         6 . The screw compressor according to  claim 1 ,
 wherein said flange provided in the inner surface of said low-pressure-side chamber is connected to said flange provided in said main casing through the sealing component, so that the space inside said steel pipe chamber is divided into the low-pressure-side space and the high-pressure-side space.   
     
     
         7 . The screw compressor according to  claim 1 ,
 wherein said flange provided in the inner surface of said low-pressure-side chamber is connected to said flange provided in said motor casing through the sealing component, so that the space inside said steel pipe chamber is divided into the low-pressure-side space and the high-pressure-side space.   
     
     
         8 . The screw compressor according to  claim 1 ,
 wherein a central axis of a shell constituting said steel pipe chamber is disposed in a horizontal direction.   
     
     
         9 . The screw compressor according to  claim 1 ,
 wherein said screw rotor includes at least a pair of male and female rotors meshing with each other.   
     
     
         10 . The screw compressor according to  claim 9 ,
 wherein an operation fluid to be compressed is a refrigerant used in a refrigeration cycle,   wherein a refrigerant having a cooling ability per unit volume flow rate equal to or less than 70% of R 407 C is used,   wherein the number of teeth of the male rotor of said screw rotor is set to four, and the number of teeth of said female rotor thereof is set to six, and   wherein the driving motor directly connected to said male rotor is driven by an inverter.   
     
     
         11 . The screw compressor according to  claim 9 ,
 wherein a central axis of said steel pipe chamber is disposed between a central axis of said male rotor and a central axis of said female rotor.   
     
     
         12 . The screw compressor according to  claim 1 , further comprising:
 a gate rotor which meshes with said screw rotor; and   a bearing which supports a shaft portion of said gate rotor.   
     
     
         13 . A screw compressor comprising:
 a screw rotor which includes a toothed portion and a shaft portion;   a gate rotor which meshes with said screw rotor;   a low-pressure-side bearing and a high-pressure-side bearing which support the shaft portion of said screw rotor;   a bearing which supports a shaft portion of said gate rotor;   a driving motor which is directly connected to the shaft portion of said screw rotor and drives said screw rotor;   a motor casing which accommodates said motor;   a main casing which accommodates said screw rotor and said gate rotor; and   a steel pipe chamber which accommodates said motor casing and said main casing,   wherein said steel pipe chamber includes a low-pressure-side chamber and a high-pressure-side chamber which are able to be divided in an axial direction, and   wherein a space inside said steel pipe chamber is divided into a low-pressure-side space and a high-pressure-side space through a flange provided on an inner surface of said steel pipe chamber, a flange provided in said main casing or said motor casing, and a sealing component provided between said flanges.   
     
     
         14 . A screw compressor comprising:
 a screw rotor;   a bearing which supports said screw rotor;   a motor which drives said screw rotor;   a motor casing which accommodates said motor;   a main casing which accommodates said screw rotor; and   a steel pipe chamber which accommodates said motor casing and said main casing,   wherein said steel pipe chamber is able to be divided in an axial direction, and   wherein a space inside said steel pipe chamber which is able to be divided is divided into a low-pressure-side space and a high-pressure-side space through a sealing component.