Compressor Oil Balancing Piping for Partial-Load Refrigeration
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Solution Overview
Problem
Conventional refrigeration systems lack a reliable and cost-effective solution for oil balancing among multiple compressors, especially in partial load conditions, leading to oil starvation or excess oil distribution due to varying compressor capacities and piping designs.
Innovation Solution
An oil balancing apparatus is introduced, featuring a first oil balancing pipe connecting oil sumps of second compressors in series and a second oil balancing pipe connecting the oil sump of the first compressor to the bottom of the first oil balancing pipe, preventing direct oil transfer between compressors and ensuring minimum oil levels are maintained across all compressors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active oil return apparatus is used to manage oil levels, then oil balancing reliability is improved, but system cost and structural complexity increase
Solution Approach 1:
The patent extracts the oil balancing function from complex active control systems and implements it through a simple passive piping structure. The oil balancing pipe is designed with specific connection points (suction port connected to suction main pipe, discharge port connected to discharge main pipe) that enable automatic oil level equalization among compressors without requiring active control mechanisms, thereby reducing system complexity while maintaining reliability.
Solution Approach 2:
The oil balancing system operates autonomously using the pressure differential and flow dynamics inherent in the refrigeration cycle. The suction port and discharge port are positioned to automatically regulate oil flow based on system operating conditions, eliminating the need for external control systems, sensors, or actuators, thus achieving self-service oil balancing.
2Device complexity
If piping design alone is used to manage oil levels, then system cost is reduced, but oil level control effectiveness deteriorates
Solution Approach 1:
The patent applies local quality by strategically positioning the suction port and discharge port at specific locations within the oil balancing pipe. The suction port is connected to the suction main pipe to tap into the low-pressure refrigerant flow, while the discharge port is connected to the discharge main pipe to utilize high-pressure flow for oil return. This localized optimization of port positions enables effective oil level control using only passive piping design.
Solution Approach 2:
The system utilizes pneumatic-hydraulic principles by leveraging the pressure differential between the suction and discharge sides of the compressors. The oil balancing pipe is designed to allow refrigerant-gas-oil mixture to flow from the high-pressure discharge side to the low-pressure suction side, automatically equalizing oil levels among compressors based on their operating conditions without requiring mechanical actuators.
3Adaptability or versatility
If compressors operate with different capacities, then system adaptability is improved, but oil distribution uniformity deteriorates
Solution Approach 1:
The oil balancing pipe serves multiple functions: it acts as a suction line for low-pressure refrigerant, a discharge line for high-pressure refrigerant, and simultaneously an oil return passage. The universal design with suction and discharge ports allows the same piping structure to serve compressors of different capacities by automatically adjusting oil flow based on each compressor's operating state, thereby maintaining oil level consistency across variable capacity operations.
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 provides reliable and economic oil balancing, preventing oil starvation and excess oil distribution, ensuring consistent operation across compressors by managing oil levels effectively even in partial load conditions.
Implementation Method 1
the suction port is configured to be connected to a suction main pipe... the discharge port is configured to be connected to a discharge main pipe... a pressure difference between different compressors
Data Source
AI summary
An oil balancing apparatus is for use with a first compressor and at least two second compressors. Suction pipes of the first compressor and the second compressors are connected in parallel to a suction main pipe and discharge pipes of the first compressor and the second compressors are connected in parallel to a discharge main pipe. The first compressor is in an operating state, and the second compressors are operated intermittently. The oil balancing apparatus includes a first oil balancing pipe connecting oil sumps of the second compressors in series, and a second oil balancing pipe connecting an oil sump of the first compressor to a bottom of the first oil balancing pipe. A refrigeration system is also disclosed.