Multi-compressor system with normally-open valves in oil balancing connections
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Solution Overview
Problem
Conventional multi-compressor refrigeration systems face issues with oil balancing and increased costs due to the use of actively controlled valves, which can lead to oil level imbalances and inefficiencies.
Innovation Solution
The system incorporates spring-loaded normally-open valves that fluidly connect and isolate the low pressure volume of each compressor with the common oil balancing line based on pressure differences, preventing bypass flows and ensuring oil level equalization without actively controlled valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If actively controlled solenoid valves are used in balancing connection lines to isolate low pressure volume from common oil balancing line, then oil level equalization is improved, but device complexity and cost increase
Solution Approach 1:
The spring-loaded normally-open valve automatically responds to pressure differences between the low pressure volume and common oil balancing line, closing when pressure differential exceeds the spring force. This self-regulating mechanism eliminates the need for external control signals, solenoids, or complex control systems while maintaining reliable oil level equalization.
Solution Approach 2:
The patent replaces the electromechanical solenoid valve system with a purely mechanical spring-loaded valve. The valve operation is driven by the pressure differential itself acting against the spring force, substituting electronic control with a simple mechanical response that is more reliable and cost-effective.
2Device complexity
If spring-loaded normally-open valves are used to connect low pressure volume with common oil balancing line, then device complexity is reduced, but bypass flow control may be insufficient
Solution Approach 1:
The valve design incorporates a spring force parameter that can be adjusted to match the maximum expected pressure differential in the system. By properly selecting the spring constant and pre-compression, the valve ensures reliable closure when pressure differential exceeds the spring force, effectively preventing bypass flows while maintaining system simplicity.
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 maintains good oil balancing properties while reducing costs, prevents bypass flows, and minimizes oil dilution and circulation rate issues, thereby enhancing the system's operating efficiency and reliability.
Implementation Method 1
each spring-loaded normally-open valve being configured to be displaced in the closed configuration when a pressure difference between a pressure prevailing in the low pressure volume of the respective compressor and a pressure prevailing in the common oil balancing line reaches a predetermined value
Data Source
AI summary
The multi-compressor system has a plurality of parallelly coupled compressors; inlet connection lines each connected to a refrigerant suction fitting of a respective compressor; outlet connection lines each connected to a refrigerant discharge fitting of a respective compressor; a common oil balancing line and balancing connection lines each connecting the common oil balancing line to an oil balancing connection of a respective compressor; and spring-loaded normally-open valves each being arranged within a respective balancing connection line or within an oil balancing connection of a respective compressor and each being configured to close when a pressure difference between a pressure prevailing in the low pressure volume of the respective compressor and a pressure prevailing in the common oil balancing line reaches a predetermined value.