Reciprocating Compressor Oil Separation With Annular Lip Return
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Solution Overview
Problem
Hermetic reciprocating piston compressors face challenges in efficiently managing oil separation and return within the compressor, leading to reduced heat exchanger efficiency and increased manufacturing costs due to the need for separate oil return mechanisms and external separators.
Innovation Solution
Incorporating a bearing-mounted check valve and an annular lip structure within the compressor case to facilitate oil separation and return, where the annular lip coalesces oil from the refrigerant flow, allowing it to drain into the crankcase, eliminating the need for separate return mechanisms and potentially downsizing external separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate external oil separator and return mechanism are used, then oil separation can be achieved, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent combines the oil separator, oil return mechanism, and bearing support function into a single integrated component mounted within the compressor case wall. This merging eliminates the need for separate external oil separators and complex return mechanisms, while maintaining effective oil separation and return to the crankcase.
Solution Approach 2:
The integrated component performs multiple functions simultaneously: it supports the crankshaft bearing, separates oil from refrigerant vapor, and provides a return path for oil to the crankcase. This multi-functionality reduces the overall number of components needed in the system.
2Reliability
If oil separation is performed externally, then oil can be removed from refrigerant, but heat exchanger efficiency decreases due to oil entrainment
Solution Approach 1:
The oil separator is positioned to remove oil from the refrigerant vapor before it enters the heat exchanger. The annular lip structure coalesces oil droplets and directs them away from the refrigerant flow path, ensuring that only purified refrigerant reaches the heat exchanger, thereby maintaining maximum heat transfer efficiency.
3Reliability
If separate oil return mechanisms are used, then oil can be returned to crankcase, but manufacturing costs increase
Solution Approach 1:
The oil return mechanism is integrated into the bearing support structure, with the check valve and drainage path formed as part of the single component. This eliminates the need for separate oil return lines, valves, and mechanisms, significantly reducing manufacturing complexity and cost while ensuring reliable oil return to the crankcase.
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 enhances refrigerant flow purity by reducing oil entrainment in the cylinders, improves heat exchanger efficiency, and reduces system manufacturing costs by integrating oil separation within the compressor, eliminating or downsizing external separators.
Implementation Method 1
the annular lip coalesces oil from the refrigerant flow
Implementation Method 2
A check valve may be in the wall below the bearing
Data Source
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AI summary
A compressor (20) has a case (22) and a crankshaft (38). The case has a number of cylinders (30, 32). For each of the cylinders, the compressor includes a piston (34) mounted for reciprocal movement at least partially within the cylinder. A connecting rod (36) couples each piston to the crankshaft. An electric motor compartment (50) of the case has a stator (42) and a rotor (40). The rotor is mounted to the crankshaft. The case has a wall (56) between the motor compartment and a crankcase compartment/sump (52). The wall bears a feature (120, 132; 420; 460) for coalescing oil entrained in a refrigerant flow (522), which flow exits the gap (90) between the rotor and the stator to prevent the oil from entering the cylinders.