Reciprocating Compressor Piston Skirt Guide Surfaces
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Solution Overview
Problem
Reciprocating compressors face inefficiencies due to friction loss between the piston and cylinder, as well as dead volume formation at the top dead center, which reduces compression efficiency.
Innovation Solution
The compressor design includes a piston with a skirt and guide surfaces to minimize friction and a projection on the piston head to reduce dead volume, allowing for smoother fluid discharge and reduced contact with the cylinder, along with a connecting rod for linear reciprocating movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piston reciprocates in the cylinder to compress the working fluid, then the compression function is achieved, but friction loss occurs between the piston and cylinder reducing efficiency
Solution Approach 1:
The piston is divided into functionally distinct segments: the head portion for compression and the skirt portion with guide surfaces for guidance. This segmentation allows each part to optimize its specific function while minimizing overall friction loss.
Solution Approach 2:
Different surfaces of the piston have different properties: the head has a smooth compression surface, while the skirt has guide surfaces with specific friction characteristics. This local differentiation optimizes both compression efficiency and friction management in different zones.
2Stability of the object's composition
If the piston head contacts the cylinder wall for guidance, then reciprocating stability is improved, but friction loss increases
Solution Approach 1:
The guidance function is extracted from the piston head and assigned to a separate skirt portion with dedicated guide surfaces. This separation allows the head to focus on compression while the skirt handles guidance, reducing overall friction.
Solution Approach 2:
The guide surfaces on the skirt act as an intermediary between the piston and cylinder wall, providing controlled contact for stability while managing friction through their specific geometry and surface properties.
3Productivity
If the piston is positioned at the top dead center, then the compression stroke is completed, but dead volume remains reducing compression efficiency
Solution Approach 1:
The piston head geometry is designed to be dynamic in its function, changing its effective position relative to the cylinder head during the compression stroke. The inclined surface allows the piston to effectively reduce dead volume by creating a sealing action near the top dead center position.
4Productivity
If the discharge hole is positioned at the top dead center, then fluid discharge is enabled, but dead volume and pulsation occur reducing efficiency
Solution Approach 1:
The discharge hole is positioned asymmetrically relative to the piston axis, and the piston head has an asymmetric inclined surface. This asymmetric configuration optimizes fluid flow patterns, reduces dead volume, and minimizes pulsation and noise during discharge.
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 minimizes friction loss, enhances stability and efficiency by reducing dead volume, and ensures smooth fluid discharge, leading to improved compression efficiency and reduced noise and pulsation.
Implementation Method 1
guide surfaces each projected from an outside circumferential surface of the skirt for guiding reciprocating movement of the head while making friction with the inside wall of the cylinder
Implementation Method 2
a piston including a head for reciprocating the cylinder while making friction with an inside wall of the cylinder, to draw a working fluid into the compression chamber, compress, and discharge the working fluid
Implementation Method 3
a connecting rod connected between the crankshaft and the piston, for converting rotation of the crankshaft into a linear reciprocating movement of the piston
Data Source
AI summary
A reciprocating compressor is provided that includes a compression chamber inside of a cylinder and a piston inserted therein. The piston includes a head, a skirt extended from a lower end of the head so as to be spaced away from an inside wall of the cylinder, and guide surfaces extended from an outside surface of the skirt. Since the skirt is not in contact with the cylinder, a friction loss between the piston and the cylinder is reduced, and the guide surfaces assist the piston to make stable reciprocation. The head has a projection so as to be inserted into a discharge hole when the piston is at a top dead center. According to this, a dead volume formed when the piston is at the top dead center is reduced, thereby improving an efficiency of the compressor.