Multistage Compressor Oil Return Layout for Fast Oil Level Control
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Solution Overview
Problem
In multistage compression systems, the existing methods for controlling oil distribution across compressors are inefficient, particularly in returning oil from high-stage to low-stage compressors, leading to uneven oil levels and difficulty in quickly adjusting the oil amount in the low-stage compressor.
Innovation Solution
A multistage compression system design where the oil return pipe is directly connected to the container of the low-stage compressor, allowing for rapid oil supply and control, with the oil discharge pipe also connected to the container to manage excess oil, ensuring balanced oil levels by positioning these pipes strategically relative to the compression part and motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the oil return pipe is connected to the suction side of the accumulator through a small hole in the suction pipe, then the system structure is simple, but the oil return response is slow and the amount of oil in the low-stage compressor cannot be quickly increased
Solution Approach 1:
The oil return system is segmented into two independent paths: (1) a fast return path through a dedicated oil return pipe connected directly to the low-stage compressor container, and (2) a slow return path through the accumulator's suction pipe with a small hole. This segmentation allows the system to simultaneously maintain simple overall structure while achieving rapid oil return when needed.
Solution Approach 2:
The low-stage compressor container serves as an intermediary chamber that receives oil from both the fast return path (oil return pipe) and the slow return path (through the accumulator). This intermediary structure enables the system to quickly adjust oil amounts by directing oil through the fast path when rapid replenishment is needed, while maintaining the simplicity of the original accumulator-based return system.
2Measurement precision
If the oil discharge pipe is connected to the suction pipe of the low-stage compressor, then the system structure is simple, but the oil level control precision is insufficient leading to oil deficiency or excess
Solution Approach 1:
The oil discharge system uses local quality differentiation by providing two discharge paths with different characteristics: (1) a precise discharge path through the oil discharge pipe connected to the container, and (2) a general discharge path through the suction pipe. The oil discharge pipe is positioned at a specific height to enable precise control of oil levels, while the overall system maintains simplicity through the existing suction pipe connection.
Solution Approach 2:
The system dynamically adjusts oil discharge based on oil level conditions. When oil level is high, excess oil is discharged through the oil discharge pipe connected to the container. When oil level is normal, discharge occurs through the suction pipe. This dynamic discharge mechanism enables precise oil level control without requiring complex active control systems.
3Reliability
If multiple oil return and discharge paths are provided in the container, then oil level control precision is improved, but the device complexity increases
Solution Approach 1:
The invention provides partial multiple paths for oil return and discharge, rather than complete multi-path systems. Specifically, one additional oil return pipe and one additional oil discharge pipe are added to the existing suction pipe connections. This partial multiplication of paths provides sufficient oil level control reliability while minimizing the increase in device complexity.
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 design enables quick and precise control of oil levels in the low-stage compressor, preventing oil deficiencies or excesses, and ensures efficient operation by reducing oil discharge from the low-stage compressor, thereby optimizing the system's performance.
Implementation Method 1
The oil return pipe returns the oil discharged by the high-stage compressor or the oil in the high-stage compressor to the low-stage compressor
Implementation Method 2
The oil return pipe and the oil discharge pipe are connected to the container
Implementation Method 3
The compression part compresses the refrigerant
Data Source
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AI summary
In a refrigeration apparatus using a plurality of multistage compressors, it has been necessary to keep an appropriate amount of refrigerator oil in each of the plurality of multistage compressors. A multistage compression system (20) has a low-stage compressor (21), a high-stage compressor (23), an oil return pipe (31), and an oil discharge pipe (32). The low-stage compressor (21) has a compression part (50), a motor (40), and a container (30). The container (30) houses the compression part (50) and the motor (40). The oil return pipe (31) and the oil discharge pipe (32) are connected to the container (30).