LIQUID PUMP OF SCREW EXPANDER

Abstract

A liquid pump of a screw expander is disclosed, applicable to an Organic Rankin Cycle (ORC). The liquid pump of a screw expander includes a semi-sealed or fully sealed shell. An expander unit and a liquid pump unit are disposed in the shell. The expander unit includes a screw rotor, and the liquid pump unit includes a screw rotor. The rotor of the expander unit is fixedly connected to the rotor of the liquid pump unit. The rotor of the liquid pump unit rotates under driving of the rotor of the expander unit. In the liquid pump of a screw expander applied to the ORC, since a resistance torque of the female rotor is small, the liquid pump does not wear even when the liquid viscosity is low, contributing to high reliability of the liquid pump. Meanwhile, the liquid pump is driven by the screw expander, thereby further improving power generation efficiency of the ORC. In addition, the semi-sealed or fully sealed shell can effectively prevent leakage of a refrigerant

Description

BACKGROUND OF THE PRESENT INVENTION

1. Field of Invention

The present invention relates to the field of Organic Rankin Cycle (ORC) technology, specifically to an ORC power generation system, and more specifically to a liquid pump of a screw expander of the ORC power generation system.

2. Description of Related Arts

Referring to FIG. 1, FIG. 1 is a typical ORC, which includes an expander 1′, a generator 2′, an evaporator 3′, a liquid pump 4′ and a condenser 5′.

A low-temperature and low-pressure liquid refrigerant is pressurized in the liquid pump 4′, and then enters the evaporator 3′ to be evaporated through heating until the refrigerant becomes an overheated gas (high temperature and high pressure). The overheated gas enters the expander 1′ to work through expansion, so as to drive the generator 2′ to generate power. After working, the low-temperature and low-pressure gas enters the condenser 5′ and is condensed to liquid, and then flows back into the liquid pump 4′, thus completing a cycle.

Most of the existing liquid pumps are open-type gear pumps or centrifugal pumps. The gear pump has the following defects: in the gear pump, one gear always drives another gear, and half of the consumed work is consumed during a driving process; meanwhile, in the ORC cycle, liquid viscosity is usually low, and the gear wears easily. The centrifugal pump has the following defect: after the centrifugal pump sucks the liquid, a pressure during the suction process is decreased, and the liquid evaporates easily, which causes efficiency of the centrifugal pump to decrease, thereby affecting efficiency of the entire ORC cycle. The open-type liquid pump has the following defect: the refrigerant leaks easily through a shaft seal.

In addition, power generation efficiency of the ORC power generation system is low; moreover, the existing gear pump or centrifugal pump is driven by a motor, which consumes power, thereby further decreasing the power generation efficiency of the ORC power generation system.

SUMMARY OF THE PRESENT INVENTION

The technical problem to be solved by the present invention is to provide a liquid pump of a screw expander, which is capable of improving reliability of the liquid pump.

In order to solve the above technical problem, the present invention adopts the following technical solution.

A liquid pump of a screw expander is provided, comprising a semi-sealed or fully sealed shell, wherein an expander unit and a liquid pump unit are disposed in the shell; the expander unit comprises a screw rotor, and the liquid pump unit comprises a screw rotor; the rotor of the expander unit is fixedly connected to the rotor of the liquid pump unit, and the rotor of the liquid pump unit rotates under driving of the rotor of the expander unit.

As a preferential solution of the present invention, the expander unit comprises an expander male rotor and an expander female rotor, wherein the liquid pump unit comprises a liquid pump male rotor and a liquid pump female rotor; an end of the expander male rotor is fixedly connected to the liquid pump male rotor, and the liquid pump male rotor rotates under driving of the expander male rotor.

As a preferential solution of the present invention, the shell comprises an expander cavity and a liquid pump cavity isolated from each other; all or a main body part of the expander male rotor, and the expander female rotor are disposed in the expander cavity; all or a main body part of the liquid pump male rotor, and the liquid pump female rotor are disposed in the liquid pump cavity; an expander suction inlet, an expander exhaust outlet, a liquid pump inlet and a liquid pump outlet are disposed on the shell.

As a preferential solution of the present invention, the expander male rotor comprises a first rotor part and a first connection part which are integrally designed; the first rotor part is disposed in the expander cavity and coordinates with the expander female rotor; the first connection part extends into the liquid pump male rotor in the liquid pump cavity.

As a preferential solution of the present invention, the liquid pump male rotor comprises a second rotor part and a second connection part which are integrally designed; the second rotor part is disposed in the liquid pump cavity and coordinates with the liquid pump female rotor; the second connection part extends into the expander male rotor in the expander cavity.

As a preferential solution of the present invention, expander female rotor bearings are separately disposed at two ends of the expander female rotor, and liquid pump female rotor bearings are separately disposed at two ends of the liquid pump female rotor; a first male rotor bearing is disposed at an end of the expander male rotor away from the liquid pump male rotor; a second male rotor bearing is disposed at the first connection part and between the first rotor part of the expander and the second rotor part of the liquid pump.

As a preferential solution of the present invention, the expander cavity and the liquid pump cavity are isolated from each other through an isolation mechanism, so that a hole is formed between the expander cavity and the liquid pump cavity; the first connection part passes through the hole and enters the liquid pump cavity.

The present invention has the following beneficial effects: in the ORC power generation system and the liquid pump of the screw expander thereof provided in the present invention, since a resistance torque of the liquid pump female rotor is very small, the liquid pump does not wear even when the liquid viscosity is very low, contributing to good reliability. Meanwhile, the liquid pump is driven by the screw expander, thereby further improving power generation efficiency of the ORC. In addition, the semi-sealed or fully sealed shell can effectively prevent leakage of the refrigerant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of composition of an ORC power generation system.

FIG. 2 is a schematic view of composition of an ORC power generation system using the present invention.

FIG. 3 is a sectional view of a liquid pump of a screw expander in a vertical direction consistent with the present invention.

FIG. 4 is a sectional view of a liquid pump of a screw expander in a horizontal direction consistent with the present invention.

LIST OF REFERENCE NUMERALS

1′ Expander

2′ Generator

3′ Evaporator

4′ Liquid pump

5′ Condenser

1 Expander

2 Generator

3 Evaporator

4 Liquid pump of a screw expander

5 Condenser

401 Expander male rotor

402 Expander female rotor

403 Liquid pump male rotor

404 Liquid pump female rotor

4051 First male rotor bearing

4052 Second male rotor bearing

4061 Expander female rotor bearing

4062 Expander female rotor bearing

4071 Liquid pump female rotor bearing

4072 Liquid pump female rotor bearing

408 Seal ring

409 Seal ring

410 Expander suction inlet

411 Expander exhaust outlet

412 Liquid pump inlet

413 Liquid pump outlet

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the present invention are described in detail with reference to the accompanying drawings below.

Embodiment 1

Referring to FIG. 2, FIG. 2 shows an ORC power generation system using the present invention. The ORC power generation system includes a condenser 5, a liquid pump 4, an evaporator 3, an expander 1, and a generator 2. The main improvement of the present invention consists in the liquid pump 4. In this embodiment, the liquid pump 4 is a liquid pump 4 of a screw expander.

Specifically, referring to FIG. 3 and FIG. 4, the liquid pump 4 of a screw expander includes a semi-sealed or fully sealed shell. The shell is formed of multiple components, and a seal ring 409 is disposed at each gap between components. An expander suction inlet 410, an expander exhaust outlet 411, a liquid pump inlet 412 and a liquid pump outlet 413 are disposed on the shell. The expander suction inlet 410 and the expander exhaust outlet 411 are respectively connected to an outlet of the evaporator 3 and an inlet of the condenser 5. The liquid pump inlet 412 and the liquid pump outlet 413 are respectively connected to an outlet of the condenser 5 and an inlet of the evaporator 3.

An expander unit and a liquid pump unit are disposed in the shell. The expander unit includes a screw rotor, and the liquid pump unit includes a screw rotor. The rotor of the expander unit is fixedly connected to the rotor of the liquid pump unit. The rotor of the liquid pump unit rotates under driving of the rotor of the expander unit.

As shown in FIG. 4, the expander unit includes an expander male rotor 401 and an expander female rotor 402. The liquid pump unit includes a liquid pump male rotor 403 and a liquid pump female rotor 404. An end of the expander male rotor 401 is fixedly connected to the liquid pump male rotor 403, and the liquid pump male rotor 403 rotates under driving of the expander male rotor 401.

The shell includes an expander cavity and a liquid pump cavity isolated from each other. All or a main body part of the expander male rotor 401, and the expander female rotor 402 are disposed in the expander cavity. All or a main body part of the liquid pump male rotor 403, and the liquid pump female rotor 404 are disposed in the liquid pump cavity. In this embodiment, the expander male rotor 401 extends into the liquid pump male rotor 403 in the liquid pump cavity.

Further referring to FIG. 4, the expander male rotor 401 includes a first rotor part and a first connection part which are integrally designed. The first rotor part is disposed in the expander cavity and coordinates with the expander female rotor 402. The first connection part extends into the liquid pump male rotor 403 in the liquid pump cavity.

Expander female rotor bearings 4061 and 4062 are separately disposed at two ends of the expander female rotor 402. Liquid pump female rotor bearings 4071 and 4072 are separately disposed at two ends of the liquid pump female rotor 404. A first male rotor bearing 4051 is disposed at an end of the expander male rotor 401 away from the liquid pump male rotor 403. A second male rotor bearing 4052 is disposed at the first connection part and between the first rotor part of the expander and the second rotor part of the liquid pump.

The expander cavity and the liquid pump cavity are isolated from each other through an isolation mechanism, so that a hole is formed between the expander cavity and the liquid pump cavity. The first connection part passes through the hole and enters the liquid pump cavity.

The seal ring 408 is used to seal and separate a rotor cavity (the liquid pump cavity) and a bearing cavity (the expander cavity), thereby ensuring effective lubrication of the bearing.

In conclusion, in the liquid pump of a screw expander provided in the present invention, since a resistance torque of the liquid pump female rotor is very small, the liquid pump does not wear even when the liquid viscosity is very low, contributing to good reliability. Meanwhile, the liquid pump is driven by the screw expander, thereby further improving the power generation efficiency of the ORC. In addition, the semi-sealed or fully sealed shell can effectively prevent leakage of the refrigerant.

Embodiment 2

This embodiment differs from Embodiment 1 in that, in this embodiment, the liquid pump male rotor extends into the expander male rotor.

Specifically, the liquid pump male rotor includes a second rotor part and a second connection part which are integrally designed. The second rotor part is disposed in the liquid pump cavity and coordinates with the liquid pump female rotor. The second connection part extends into the expander male rotor in the expander cavity.

In addition, in the foregoing embodiments, both the expander unit and the liquid pump unit include two screws. Definitely, the expander unit and the liquid pump unit may include other numbers of screws.

Herein, the description and application of the present invention are illustrative, and the scope of the present invention is not intended to be limited to the above embodiments. Variations and changes to the embodiments disclosed herein are possible. Replacement made to the embodiments and equivalent parts are well-known to persons skilled in the art. It should be known to persons skilled in the art that, the present invention can be implemented in other forms, structures, arrangements, ratios and through other components, materials, and parts without departing from the script or essential features of the present invention. Other variations and changes may be made to the embodiments disclosed herein without departing from the scope and script of the present invention.

Claims

1. A liquid pump of a screw expander, comprising a semi-sealed or fully sealed shell, wherein an expander unit and a liquid pump unit are disposed in the shell;

the expander unit comprises a screw rotor, and the liquid pump unit comprises a screw rotor;

the rotor of the expander unit is fixedly connected to the rotor of the liquid pump unit, and the rotor of the liquid pump unit rotates under driving of the rotor of the expander unit.

2. The liquid pump of a screw expander as in claim 1, wherein

the expander unit comprises an expander male rotor and an expander female rotor, and the liquid pump unit comprises a liquid pump male rotor and a liquid pump female rotor;

an end of the expander male rotor is fixedly connected to the liquid pump male rotor, and the liquid pump male rotor rotates under driving of the expander male rotor.

3. The liquid pump of a screw expander as in claim 2, wherein

the shell comprises an expander cavity and a liquid pump cavity isolated from each other; all or a main body part of the expander male rotor, and the expander female rotor are disposed in the expander cavity; and all or a main body part of the liquid pump male rotor, and the liquid pump female rotor are disposed in the liquid pump cavity;

an expander suction inlet, an expander exhaust outlet, a liquid pump inlet and a liquid pump outlet are disposed on the shell.

4. The liquid pump of a screw expander as in claim 3, wherein

the expander male rotor comprises a first rotor part and a first connection part which are integrally designed;

the first rotor part is disposed in the expander cavity and coordinates with the expander female rotor; and the first connection part extends into the liquid pump male rotor in the liquid pump cavity.

5. The liquid pump of a screw expander as in claim 3, wherein

the liquid pump male rotor comprises a second rotor part and a second connection part which are integrally designed;

the second rotor part is disposed in the liquid pump cavity and coordinates with the liquid pump female rotor; and the second connection part extends into the expander male rotor in the expander cavity.

6. The liquid pump of a screw expander as in claim 4, wherein

expander female rotor bearings are separately disposed at two ends of the expander female rotor, and liquid pump female rotor bearings are separately disposed at two ends of the liquid pump female rotor;

a first male rotor bearing is disposed at an end of the expander male rotor away from the liquid pump male rotor, and a second male rotor bearing is disposed at the first connection part and between the first rotor part of the expander and the second rotor part of the liquid pump.

7. The liquid pump of a screw expander as in claim 6, wherein

the expander cavity and the liquid pump cavity are isolated from each other through an isolation mechanism, so that a hole is formed between the expander cavity and the liquid pump cavity, and the first connection part passes through the hole and enters the liquid pump cavity.

8. A liquid pump of a screw expander, applied to an Organic Rankin Cycle (ORC), comprising a semi-sealed or fully sealed shell, wherein an expander male rotor, an expander female rotor, a liquid pump male rotor and a liquid pump female rotor are disposed in the shell; an end of the expander male rotor is fixedly connected to the liquid pump male rotor, and the liquid pump male rotor rotates under driving of the expander male rotor;

the shell comprises an expander cavity and a liquid pump cavity isolated from each other; all or a main body part of the expander male rotor, and the expander female rotor are disposed in the expander cavity; all or a main body part of the liquid pump male rotor, and the liquid pump female rotor are disposed in the liquid pump cavity; an expander suction inlet, an expander exhaust outlet, a liquid pump inlet and a liquid pump outlet are disposed on the shell;

the expander male rotor comprises a first rotor part and a first connection part which are integrally designed; the first rotor part is disposed in the expander cavity and coordinates with the expander female rotor; and the first connection part extends into the liquid pump male rotor in the liquid pump cavity;

expander female rotor bearings are separately disposed at two ends of the expander female rotor, and liquid pump female rotor bearings are separately disposed at two ends of the liquid pump female rotor; a first male rotor bearing is disposed at an end of the expander male rotor away from the liquid pump male rotor; a second male rotor bearing is disposed at the first connection part and between the first rotor part of the expander and the second rotor part of the liquid pump; and

the expander cavity and the liquid pump cavity are isolated from each other through an isolation mechanism, so that a hole is formed between the expander cavity and the liquid pump cavity, and the first connection part passes through the hole and enters the liquid pump cavity