Double-screw liquid pump

Abstract

A double-screw liquid pump is provided, which is applicable to an Organic Rankin Cycle (ORC). The double-screw liquid pump includes a semi-sealed or fully sealed shell, and the shell includes a first cavity and a second cavity isolated from each other. A motor is disposed in the first cavity, and a main body part of a double-screw is disposed in the second cavity. At least one rotor of the double-screw is fixedly connected to a rotor of the motor, and the double-screw rotates through driving of the motor. A liquid refrigerant injection inlet and a refrigerant outlet are disposed on the first cavity, and the motor is cooled through evaporation of a liquid refrigerant; a liquid inlet and a liquid outlet are disposed on the second cavity. In the double-screw liquid pump applied to the ORC provided in the present invention, since a resistance torque of the female rotor is very small, the liquid pump does not wear even when the liquid viscosity is very low, contributing to good reliability, and thereby improving power generation efficiency of the ORC. In addition, the semi-sealed or fully sealed shell can effectively prevent leakage of the refrigerant.

What is claimed is: 
     
         1 . A double-screw liquid pump comprising a semi-sealed or fully sealed shell, wherein the shell comprises a first cavity and a second cavity isolated from each other;
 a motor is disposed in the first cavity, and a main body part of a double-screw is disposed in the second cavity;   at least one rotor of the double-screw is fixedly connected to a rotor of the motor, and the double-screw rotates through driving of the motor;   a liquid refrigerant injection inlet and a refrigerant outlet are disposed on the first cavity; and the motor is cooled through evaporation of a liquid refrigerant; and   a liquid inlet and a liquid outlet are disposed on the second cavity.   
     
     
         2 . The double-screw liquid pump as in  claim 1 , wherein
 the double-screw comprises a male rotor and a female rotor; and a first end of the male rotor is fixedly connected to the rotor of the motor.   
     
     
         3 . The double-screw liquid pump as in  claim 2 , wherein
 the male rotor comprises a rotor part and a connection part which are integrally designed;   the rotor part is disposed in the second cavity and coordinates with the female rotor; the connection part extends into the motor in the first cavity;   the first cavity and the second cavity are isolated from each other through an isolation mechanism, so that a hole is formed between the first cavity and the second cavity; the connection part passes through the hole and enters the first cavity, and an end of the connection part away from the rotor part is fixedly connected to the rotor of the motor.   
     
     
         4 . The double-screw liquid pump as in  claim 3 , wherein
 a first male rotor bearing is disposed at a second end of the male rotor away from the motor, and female rotor bearings are separately disposed at two ends of the female rotor.   
     
     
         5 . The double-screw liquid pump as in  claim 4 , wherein
 a second male rotor bearing is disposed at the connection part and between the rotor part of the male rotor and the rotor of the motor.   
     
     
         6 . The double-screw liquid pump as in  claim 5 , wherein
 the connection part and an end of the second male rotor bearing close to the rotor of the motor are sealed through a shaft seal.   
     
     
         7 . The double-screw liquid pump as in  claim 1 , wherein
 the motor is an inverter motor or a motor with a fixed rotating speed.