Scroll Compressor Outlet Chamber Drain for Low Flow Oil Return
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Solution Overview
Problem
In scroll compressors, low mass flows lead to unintentional oil separation in the outlet chamber, resulting in inadequate lubrication, as the large volume chamber inadvertently acts as an oil separator, preventing oil from being returned to the compressor unless operating at high speeds.
Innovation Solution
A scroll compressor design that includes an outlet chamber drain connecting directly to the oil return channel, allowing oil to be efficiently returned to the suction pressure chamber even at low mass flows, with optional features like an outlet chamber valve and nozzle-like constriction for precise control, ensuring consistent lubrication without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the outlet chamber is designed with large volume to dampen discharge pressure pulses, then NVH behavior is improved, but oil separation occurs at low mass flows causing inadequate lubrication
Solution Approach 1:
The outlet chamber is segmented into two functional zones: an upper damping zone for pressure pulse absorption and a lower oil collection zone with drain opening for oil separation. This segmentation allows the chamber to simultaneously perform both NVH damping and oil return functions without requiring separate components.
Solution Approach 2:
The geodetic lower region of the outlet chamber acts as an intermediary zone that collects separated oil from the refrigerant-oil mixture and channels it through the drain opening to the oil return channel, mediating between the compression chamber and the oil return system.
2Stability of the object's composition
If the outlet chamber volume is large, then pressure pulse damping is improved, but flow velocity is reduced causing unintentional oil separation
Solution Approach 1:
Different regions of the outlet chamber are assigned different functional qualities: the upper region provides volume for pressure damping while the lower region provides a drain opening for oil removal. This local differentiation allows the chamber to maintain pressure stability while enabling oil return even at low flow velocities.
3Device complexity
If no additional oil separation components are added, then device complexity is reduced, but oil return capability at low mass flows is insufficient
Solution Approach 1:
The outlet chamber is designed to perform multiple functions simultaneously: pressure pulse damping, oil separation, and oil return. By integrating the oil return function into the existing chamber structure through a drain opening, the system achieves reliable oil return at low mass flows without adding separate oil separation components.
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 enhances oil management, improves performance characteristics, and maintains efficiency and back-pressure characteristics, ensuring reliable lubrication across all operating conditions, including low mass flows without increasing back-pressure.
Implementation Method 1
a large volume provides damping of the discharge pressure pulses and thus an improved NVH behavior
Implementation Method 2
the reduction in the flow velocity in the outlet chamber unintentionally acts as an oil separator on account of the different mass inertias of oil and refrigerant
Implementation Method 3
The pressure difference is equalized via a nozzle element or the like
Data Source
AI summary
A scroll compressor for refrigerant-oil mixtures with oil return, including a housing element and a fixed scroll, wherein the housing element is connected to the fixed scroll by means of a seal in such a way that an outlet chamber is formed between the housing element and the fixed scroll, wherein, for oil separation and oil return purposes, an oil separation chamber, which has a high-pressure refrigerant outlet and an oil collection area, and an oil return channel towards a suction pressure chamber are arranged downstream of the outlet chamber, the scroll compressor being characterized in that an outlet chamber drain for draining oil into the oil return channel of the oil separation chamber is formed in the geodetic lower region of the outlet chamber.