Twin Screw Compressor Startup Bypass Valve
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Solution Overview
Problem
Conventional oil flooded twin screw rotary compressors experience high motor torque requirements during start-up due to the need to push oil through the compression chamber, and require time-consuming oil drainage at shut-down, as oil drains from the compression chamber when not in operation.
Innovation Solution
A fluid passage bypass configuration with a one-way valve allows oil and other fluids to escape from the working chamber during start-up, reducing motor torque requirements and eliminating the need for oil drainage at shut-down by directing fluids through a bypass channel and discharge port, rather than through the compression chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil is positioned in the compression chamber during operation, then lubrication is provided, but high motor torque is required during start-up to push oil through the chamber
Solution Approach 1:
The compression chamber is segmented into an oil introduction region and a compression region. The oil introduction region allows oil to be introduced directly into the compression chamber without requiring high torque to push oil through the entire chamber, while the compression region maintains proper compression function. This spatial segmentation resolves the contradiction by localizing oil introduction to a specific zone.
Solution Approach 2:
A bypass passage acts as an intermediary pathway between the oil reservoir and the compression chamber. This bypass allows oil to reach the compression chamber during start-up without requiring the motor to push oil through the entire compression volume, thereby reducing start-up torque while still providing necessary lubrication.
2Loss of substance
If oil drains from the compression chamber when not in operation, then oil is removed from the chamber, but time-consuming drainage is required at shut-down
Solution Approach 1:
The bypass passage is pre-configured to allow oil to flow from the compression chamber to the oil reservoir during normal operation. This preliminary positioning of oil in the bypass passage enables rapid oil removal at shut-down without requiring time-consuming drainage procedures, as the oil is already positioned for quick evacuation.
Solution Approach 2:
The bypass passage maintains continuous oil flow capability during operation, allowing oil to continuously move from the compression chamber to the reservoir. This continuous action ensures that at shut-down, oil is already in motion and positioned for immediate drainage, eliminating the need for separate drainage operations and reducing shutdown time.
3Force
If a bypass passage is added to allow oil escape during start-up, then motor torque is reduced, but device complexity increases
Solution Approach 1:
The bypass passage is merged with the existing oil reservoir and compression chamber structure. The bypass inlet is positioned at the bottom of the compression chamber and integrates with the oil reservoir, combining multiple functions (oil introduction, oil escape, lubrication) into a single integrated pathway. This merging reduces device complexity by eliminating separate components while still providing torque reduction benefits.
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
The bypass configuration reduces the motor torque required for start-up, allowing the compressor to operate at higher pressures and eliminating the need for oil drainage, thereby enhancing operational efficiency and flexibility in compressor design.
Implementation Method 1
The flow control member permits fluid to only flow in a direction leading from the working chamber, into the fluid channel, and out the fluid passage outlet. The control member prevents any and all of the fluid exiting from the working chamber from flowing back into the chamber through the fluid passage inlet.
Data Source
AI summary
A twin screw compressor has a working chamber bypass that is used at start-up of the compressor. This system provides pressure relief by allowing oil or other fluid to pass through it. The bypass includes a fluid passage that extends from the working chamber to the discharge port with a one way valve disposed inside the passage.