Positive-Displacement Compressor Automatic Compression Ratio Adjustment
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Solution Overview
Problem
Existing positive-displacement compressors in conditioning and refrigeration systems face inefficiencies due to fixed discharge ports, leading to deviations in compression ratio and pressure oscillations, resulting in over-compression or under-compression, and require complex external control systems for adjustment.
Innovation Solution
A positive-displacement compressor with an automatic compression ratio-adjustment system featuring mechanical valve means that vary the aperture of discharge ports based on pressure differences between the compression and delivery chambers, allowing for instantaneous and independent adjustment of compression ratio without external control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed-size discharge port is used in the compression chamber, then the compressor structure is simple, but the compression ratio deviates from the nominal value as operating conditions change, resulting in efficiency losses
Solution Approach 1:
The discharge port is transformed from a fixed structure to a dynamic adjustable structure. A movable element (piston or plug) is introduced that can shift position along the discharge port passage, dynamically changing the effective discharge area according to operating conditions, thereby maintaining optimal compression ratio across varying system pressures
Solution Approach 2:
The effective discharge port area is changed as a variable parameter rather than a fixed dimension. By adjusting the position of the movable element, the discharge area is modified to adapt to changing system conditions, optimizing the compression ratio for different operating states without complicating the overall compressor structure
2Adaptability or versatility
If external control valves and microprocessor systems are used to adjust compression ratio, then compression ratio adjustment is achievable, but device complexity and manufacturing costs increase
Solution Approach 1:
The compression ratio adjustment system is made self-regulating through a mechanical feedback mechanism. The movable element is directly actuated by the pressure differential between compression and delivery chambers, eliminating the need for external sensors, control valves, or microprocessors. The system automatically adjusts itself based on real-time pressure conditions
Solution Approach 2:
A mechanical intermediary (movable element with sealing contact) is introduced to directly couple the pressure differential to the discharge area adjustment. This mechanical linkage serves as a direct mediator that translates pressure imbalance into positional adjustment of the discharge port, providing instantaneous and accurate control without electronic intermediaries
3Adaptability or versatility
If pressure measurement valves are used to control shutter position, then compression ratio can be adjusted, but response time increases due to pressure reading delays
Solution Approach 1:
Electronic pressure sensing and control systems are replaced with a purely mechanical pressure-responsive mechanism. The movable element is directly actuated by the mechanical force resulting from pressure differential, eliminating the time delay associated with electronic signal transmission, processing, and actuation. The response is instantaneous and directly proportional to the pressure imbalance
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 solution enables efficient and cost-effective automatic adjustment of compression ratio, maintaining optimal efficiency and reducing manufacturing complexity and costs by eliminating the need for external control systems, while preventing over-compression or under-compression.
Implementation Method 1
mechanical valve means interposed between the compression chamber and the delivery chamber and configured to automatically vary the aperture of the at least one discharge port according to the difference in pressure existing between the delivery chamber and the compression chamber
Data Source
AI summary
A positive-displacement compressor having an automatic system for adjusting compression ratio and designed for installation in a conditioning or refrigeration system for a fluid includes a suction chamber for sucking the fluid with a variable suction pressure, a delivery chamber for delivering the fluid with a delivery pressure greater than the suction pressure, a compression chamber interposed between the suction chamber and the delivery chamber and communicating with the delivery chamber via one or more discharge ports, a compression element to compress the fluid to the compression pressure, a motor driving the compression element, and an adjusting system of the compression ratio. The adjustment system includes a mechanical valve interposed between the compression chamber and the delivery chamber that automatically varies discharge port apertures in response to a pressure differential between delivery chamber and compression chamber to instantaneously equalize compression and and delivery pressure and improve compressor efficiency.