Two-stage rotary compressor
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Solution Overview
Problem
Rotary compressors face challenges in simultaneously increasing stroke volume and compression period while reducing mechanical loss and ensuring durability, due to the generation of axial maximum gas forces that lead to increased friction and reduced durability.
Innovation Solution
A two-stage rotary compressor configuration is implemented, where the first compression unit has a larger number of vanes to secure suction flow rate and the second compression unit has fewer vanes to increase compression period, with the axial maximum gas forces from both units counteracting each other to reduce the net reaction force on the rotation shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the number of vanes is increased to increase stroke volume, then the stroke volume is increased, but the suction period and compression period are decreased and mechanical loss is increased
Solution Approach 1:
The compression process is divided into two separate stages with different numbers of vanes. The first compression unit has a larger number of vanes (5 vanes) to increase stroke volume, while the second compression unit has a smaller number of vanes (3 vanes) to maintain adequate compression period. This segmentation allows each unit to be optimized for its specific function without compromising the other.
2Volume of moving object
If the number of vanes is increased to increase stroke volume, then the stroke volume is increased, but the suction period and compression period are decreased
Solution Approach 1:
The compression system is segmented into two units: the first unit with 5 vanes handles stroke volume requirements, while the second unit with 3 vanes ensures adequate suction and compression periods. This segmentation resolves the contradiction by allowing different vane configurations in different stages of the compression process.
3Power
If axial maximum gas force is generated in the discharge region, then compression is achieved, but friction is increased and durability is reduced
Solution Approach 1:
The second compression unit is positioned and configured to generate axial maximum gas force in the opposite direction to that of the first compression unit. These opposing forces counterbalance each other, reducing the net axial force on the rotation shaft and thereby decreasing friction and improving durability while maintaining compression effectiveness.
4Power
If axial maximum gas force from both compression units is utilized, then compression power is improved, but frictional force and mechanical loss are increased
Solution Approach 1:
The axial maximum gas forces from the first and second compression units are configured to act in opposite directions, creating a counterbalancing effect. This allows both units to contribute to compression power while their opposing forces reduce the net frictional load on the rotation shaft, thereby reducing mechanical loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for increased stroke volume and compression period while minimizing mechanical loss and enhancing the reliability of the compressor by reducing frictional forces and maintaining durability.
Implementation Method 1
Each vane is withdrawn outwardly from each vane slot and brought into close contact with an inner circumferential surface of the cylinder via a back pressure of the oil generated at a rear end and a centrifugal force from a rotation of the roller.
Implementation Method 2
The refrigerant introduced into the suction chamber is compressed to a constant pressure by the vane moving along the inner circumferential surface of the cylinder.
Data Source
AI summary
The present disclosure relates to a two-stage rotary compressor in which refrigerant inhaled into a compression space of a cylinder is compressed sequentially in two axially connected compression chambers and then is discharged. A rotary compressor according to an embodiment of the present disclosure includes a first compression unit and a second compression unit arranged on and along a single rotation shaft. Middle-pressure refrigerant discharged from the first compression unit flows into the second compression unit. A maximum gas force of the first compression unit and a maximum gas force of the second compression unit counteract with each other, thereby reducing a reaction force acting on a rotation shaft. According to the present disclosure, a single rotary compressor is configured to separately achieve the stroke volume increase and the compression period increase.