Multi-Stage Rotary Compressor Pressure Equalization
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Solution Overview
Problem
Multi-stage rotary compressors face increased driving load and friction due to pressure differences between compression chambers and the hermetic casing, leading to energy loss and potential malfunctions from abrupt pressure rises during initial operation.
Innovation Solution
The compressor is configured with first and second pressure chambers within the hermetic casing, separated by partitions, and a pressure adjustment channel with a reed valve to equalize pressures, allowing gas flow from the first to the second pressure chamber when pressures exceed a preset level, reducing friction and preventing overloads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hermetic casing is kept at high interior pressure to maintain structural integrity, then the compressor can handle high discharge pressures, but the pressure difference between the first compression chamber and hermetic casing increases, causing excessive force on the first vane and increased driving load
Solution Approach 1:
The hermetic casing interior is divided into a first pressure chamber surrounding the first compression chamber and a second pressure chamber surrounding the second compression chamber. This segmentation allows each chamber to be pressurized independently to match the discharge pressure of its respective compressor stage, eliminating the excessive pressure difference that caused high forces on the first vane while maintaining overall structural integrity.
2Strength
If the hermetic casing is kept at high interior pressure to maintain structural integrity, then the compressor can handle high discharge pressures, but the pressure difference causes increased frictional wear between the first vane and first roller, reducing reliability
Solution Approach 1:
The hermetic casing interior is divided into a first pressure chamber surrounding the first compression chamber and a second pressure chamber surrounding the second compression chamber. This segmentation allows each chamber to be pressurized independently to match the discharge pressure of its respective compressor stage, eliminating the excessive pressure difference that caused high forces on the first vane and subsequent frictional wear, thereby improving reliability.
3Quantity of substance
If refrigerant liquid is introduced into the first compression chamber during initial operation, then the compression chamber can be filled with refrigerant, but the abrupt pressure rising generates overload and prevents smooth startup
Solution Approach 1:
A pressure adjustment channel with a pressure adjustment valve is provided to equalize the pressure between the first and second pressure chambers before normal operation begins. This preliminary pressure equalization prevents abrupt pressure rises when refrigerant liquid is introduced, allowing smooth startup without overload while still enabling complete refrigerant filling.
Solution Approach 2:
The pressure adjustment channel acts as an intermediary mechanism between the first and second pressure chambers. It includes a pressure adjustment valve that opens when the pressure difference exceeds a preset value, allowing refrigerant to flow from the first to the second pressure chamber and equalize pressures, thereby preventing abrupt pressure rises during startup.
4Reliability
If a pressure adjustment valve is added to equalize pressures between chambers, then abrupt pressure rises are prevented, but the device complexity increases
Solution Approach 1:
The pressure adjustment valve operates automatically based on the pressure difference between the first and second pressure chambers. When the pressure difference exceeds a preset value, the valve opens to allow refrigerant flow from the first to the second pressure chamber, equalizing pressures without requiring external control systems or complex mechanisms. This self-regulating approach maintains reliability while minimizing added complexity.
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 reduces driving load, minimizes friction between vanes and rollers, ensures smooth compressor startup, and enhances durability by equalizing pressures and preventing abrupt pressure rises.
Implementation Method 1
a pressure adjustment channel, which communicates the first pressure chamber with the second pressure chamber, and a pressure adjustment valve, which opens the pressure adjustment channel when a pressure difference between the first and second pressure chambers exceeds a preset value to allow the gas to flow from the first pressure chamber to the second pressure chamber
Implementation Method 2
the first and second vanes are kept in close contact with outer circumferences of the first and second rollers, respectively, when they are pressed inward in the respective compression chambers to compress a refrigerant
Data Source
AI summary
A multi-stage rotary compressor to reduce a driving load and prevent a malfunction due to an abrupt pressure rising. In the compressor of the type including first and second compressing units mounted in a hermetic casing thereof to compress a gas, the gas being primarily compressed in the first compressing unit and secondarily compressed in the second compressing unit, the interior of the hermetic casing is divided into a plurality of spaces including first and second pressure chambers. The first pressure chamber surrounds the first compressing unit and is kept at a discharge pressure of the first compressing unit, and the second pressure chamber surrounds the second compressing unit and is kept at a discharge pressure of the second compressing unit.