Reciprocating Compressor Rod Ring Sealing Groove Design
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Solution Overview
Problem
Conventional reciprocating compressors face challenges in preventing gas leakage between the piston rod and rear head, especially under high pressure, due to manufacturing inaccuracies and the need for multiple rod packings, which increases the compressor's size.
Innovation Solution
The design incorporates a rod ring portion with an annular groove on the piston rod and a sliding contact with the rear head, enhancing sealing performance by maintaining contact pressure even under high pressure, reducing the risk of gas leakage without the need for extensive additional packing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple rod packings are arranged along the piston rod to prevent gas leakage, then the sealing reliability is improved, but the compressor size increases in the extension direction of the piston rod
Solution Approach 1:
The rod packing is divided into multiple rod ring portions arranged axially along the piston rod. Each rod ring portion has an inner circumferential surface that contacts the outer circumferential surface of the piston rod, creating multiple sealing zones. This segmentation allows effective sealing distribution along the piston rod while controlling the overall axial length of the compressor.
2Reliability
If the inner circumferential portion of the rod packing is pushed against the outer circumferential surface of the piston rod to prevent gas leakage, then the sealing performance is improved, but under high pressure the gas pushes out the rod packing causing increased gap and leakage
Solution Approach 1:
The rod ring portions are designed with specific local geometric features including axial length, radial thickness, and groove dimensions that optimize the contact pressure distribution. The groove depth and width are specifically designed to maintain appropriate contact pressure between the rod ring inner circumferential surface and the piston rod outer circumferential surface, preventing both excessive pressure concentration and insufficient sealing under high gas pressure conditions.
3Reliability
If the rod ring portion is designed with groove fitting to maintain contact pressure, then the sealing reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The grooves are pre-formed on the piston rod outer circumferential surface with predetermined dimensions and positions before the rod ring portions are installed. This preliminary action ensures proper alignment and fit when the rod rings are mounted, reducing the need for high-precision field assembly while maintaining reliable sealing contact under operating conditions.
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 configuration effectively prevents gas leakage while maintaining a compact compressor size by ensuring strong contact pressure between the rod ring and the rear head, even at high pressures, thus reducing the risk of gas leakage and thermal deformation.
Implementation Method 1
an outer circumferential portion in sliding contact with an inner circumferential surface of the rear head while the piston rod reciprocates
Data Source
AI summary
This application discloses a reciprocating compressor including: a piston rod extending along a predetermined central axis that crosses an opening formed in an end of a cylinder, the piston rod being coupled to a piston and a crank mechanism to convey driving force from the crank mechanism to the piston; a rear head penetrated by the piston rod, the rear head closing the opening of the cylinder; and a rod ring portion configured to prevent a gas in the cylinder from leaking out from a gap between the rear head and the piston rod. The piston rod includes an outer circumferential surface on which an annular groove portion surrounding the central axis of the piston rod is formed. The rod ring portion includes an inner circumferential portion inserted into the groove portion, and an outer circumferential portion in sliding contact with an inner circumferential surface of the rear head.