Compressor Piston Grooves for Refrigerant Flow
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Solution Overview
Problem
In hermetic compressors, the dead space within the cylinder cavity leads to inefficiencies as not all refrigerant can be discharged during the compression cycle, resulting in reduced compressor yield due to increased energy consumption and flow difficulties caused by narrowing cross sections and turbulences.
Innovation Solution
The compressor features a piston with grooves on its protrusion extending towards the top end, which prevents sudden narrowing of the flow path cross section, guiding refrigerant flow and minimizing dead space, thereby ensuring controllable discharge and reducing flow losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a projection is provided on the piston to decrease dead space, then the dead space is reduced, but the refrigerant flow path is narrowed causing turbulence and flow difficulty
Solution Approach 1:
The projection on the piston is segmented by providing grooves that divide the projection into multiple regions. This segmentation allows the refrigerant to flow through multiple paths rather than being forced through a single narrowed path, reducing turbulence while maintaining dead space reduction benefits
Solution Approach 2:
The grooves are positioned at specific locations on the projection to create local flow channels. This local quality modification allows different regions of the projection to serve different functions - some areas reduce dead space while grooved areas maintain refrigerant flow paths
2Volume of stationary object
If the cross section of the flow path is narrowed to reduce dead space, then the dead space is decreased, but the refrigerant acceleration increases causing temperature rise and pressure decrease
Solution Approach 1:
By segmenting the projection with grooves, the refrigerant flow is divided into multiple streams that can accelerate more gradually. This prevents the sudden single-point acceleration that causes temperature rise, while still maintaining the overall dead space reduction
3Volume of stationary object
If the projection is seated in the discharge port to minimize dead space, then the dead space is reduced, but the refrigerant discharge becomes difficult due to flow path obstruction
Solution Approach 1:
The grooves segment the projection to create multiple discharge paths through the discharge port. This allows the projection to occupy space that would otherwise be dead space, while the grooves ensure refrigerant can still discharge efficiently through multiple channels
Solution Approach 2:
The grooves act as intermediary flow channels that mediate between the projection (which reduces dead space) and the discharge port (which requires open flow paths). The grooves provide the intermediate pathways that allow both dead space reduction and efficient discharge to coexist
Data Source
Figure 1
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AI summary
The present invention relates to a hermetic compressor (1 ), used in household appliances, preferably in cooling devices. The compressor (1 ) comprises a cylinder (2) wherein the refrigerant is received, a cylinder head (3) disposed on the cylinder (2), a valve table (4) whereon the cylinder head (3) is emplaced, a discharge hole (5) on the valve table (4) wherefrom the refrigerant received into the cylinder (2) is discharged, a piston (6) disposed inside the cylinder (2) that activates the refrigerant by reciprocating inside the cylinder (2) and a protrusion (7) arranged on the piston (6) that is seated in the discharge hole (5) when the piston (6) reaches the top dead center.