Oil Sump Fairing for Scroll Compressor Motor Cooling and Low OCR
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Solution Overview
Problem
Conventional scroll compressors experience increased oil circulation rates (OCR) due to refrigerant flow impacting the oil surface in the sump, which is detrimental to variable speed compressors operating at high speeds, while also compromising motor cooling efficiency.
Innovation Solution
Incorporation of an oil sump fairing that redirects refrigerant flow away from the oil surface, preventing direct impact and entrainment, and includes a refrigerant guiding device to channel refrigerant through the electric motor, enhancing motor cooling and reducing OCR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigerant is forced to flow through the electric motor from upper stator end winding to lower stator end winding, then motor cooling is improved, but oil circulation rate increases due to direct impact on oil surface
Solution Approach 1:
A refrigerant deflector is introduced as an intermediary component between the refrigerant flow and the oil surface. The deflector intercepts the downward flowing refrigerant and redirects it away from the oil sump, preventing direct impact. This allows the refrigerant to cool the motor effectively while avoiding oil entrainment and excessive OCR.
2Quantity of substance
If refrigerant flow directly impacts the oil surface in the oil sump, then oil is entrained in the refrigerant flow, but this increases oil circulation rate which is harmful for variable speed compressors
Solution Approach 1:
The refrigerant deflector applies preliminary anti-action by preventing the harmful effect before it occurs. It intercepts the refrigerant flow before it can directly impact the oil surface, thereby preemptively avoiding oil entrainment and the subsequent increase in OCR that would harm variable speed compressor operation.
3Quantity of substance
If oil circulation rate is increased, then more oil is carried by refrigerant, but this creates harmful effects for variable speed compressor operation at high speed
Solution Approach 1:
The refrigerant deflector serves as a mediator that separates the refrigerant flow path from the oil surface. By redirecting the refrigerant away from the oil sump, it prevents oil from being picked up and carried by the refrigerant, thereby enabling the compressor to operate at high speeds without the harmful effects of excessive oil circulation.
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
The oil sump fairing reduces OCR and improves motor cooling by separating oil from the refrigerant flow, optimizing operation of variable speed compressors, especially at high speeds.
Implementation Method 1
refrigerant flow, flowing downwardly through the electric motor... from the upper stator end winding to the lower stator end winding... improve the cooling of the electric motor
Implementation Method 2
oil sump fairing arranged between a lower end of the electric motor and a free surface of oil stored in the oil sump, the oil sump fairing being configured to prevent a refrigerant flow... to directly impact the free surface of the oil
Data Source
AI summary
A scroll compressor including a hermetic casing provided with a suction inlet; a compression unit; a drive shaft configured to drive an orbiting scroll of the compression unit in an orbital movement; an electric motor coupled to the drive shaft; an oil sump; a refrigerant guiding device configured to force a main part of a refrigerant, entering the scroll compressor through the suction inlet, to flow downwardly through the electric motor, before reaching the compression unit; and an oil sump fairing arranged between a lower end of the electric motor and a free surface of oil stored in the oil sump, the oil sump fairing being configured to prevent a refrigerant flow, emerging from the lower end of the electric motor, to directly impact the free surface of the oil stored in the oil sump.