Reciprocating Compressor Rod Packing Replacement

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Solution Overview

Problem

Conventional reciprocating compressors require extensive disassembly to replace rod packing, which is time-consuming and poses challenges due to the heavy weight of the packing, necessitating a more efficient and less labor-intensive method for replacement.

Innovation Solution

The design incorporates a piston rod with a first and second rod portion of different diameters, allowing the piston to be separated from the second rod portion, enabling the rod packing to be replaced without disassembling the crank mechanism, and a nut and ring member configuration for secure fixation and easy removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the rod packing is replaced by disassembling the crank mechanism and piston rod in conventional compressors, then the rod packing can be accessed and replaced, but the replacement process takes a long period of time and requires extensive disassembly

Engineering Contradiction:
Improverod packing replaceabilityVSAvoidrod packing replacement time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The piston rod is divided into a first rod portion and a second rod portion with different diameters. The rod packing is positioned on the first rod portion and can be separately accessed by removing only the piston from the second rod portion, without needing to disassemble the entire crank mechanism. This segmentation allows the rod packing to be replaced independently, significantly reducing replacement time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rod packing is extracted as a separately replaceable component that can be removed by detaching only the piston from the piston rod. The design allows the rod packing to be taken out through the insertion hole in the piston without requiring disassembly of the crank mechanism or the entire piston rod assembly, enabling quick replacement while the crank mechanism remains coupled.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the rod packing is fixed upward within the compressor, then the packing is securely positioned, but the operator must receive the heavy weight of the packing during dismounting operations

Engineering Contradiction:
Improverod packing positioningVSAvoidrod packing dismounting ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The second rod portion serves as an intermediary element that facilitates the removal of the rod packing. By making the second rod portion thinner than the first rod portion and providing an insertion hole through the piston, the design creates a pathway that allows the rod packing to be drawn out toward the second rod portion and removed without requiring the operator to support the full weight of the packing during extraction.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the piston rod has a uniform diameter throughout, then the structure is simple and strong, but the rod packing cannot be easily removed without disassembling the entire piston rod and crank mechanism

Engineering Contradiction:
Improvepiston rod strengthVSAvoidrod packing accessibility
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The piston rod has different diameters at different locations: the first rod portion has a larger diameter to maintain strength and support the rod packing, while the second rod portion has a smaller diameter to allow easy access and removal of the rod packing through the insertion hole in the piston. This local variation in diameter allows the rod packing to be accessed and replaced without disassembling the entire piston rod or crank mechanism, while maintaining the overall structural integrity of the piston rod.

Inventive Principle:
Principle #3Local quality

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 allows for quick and easy replacement of rod packing with minimal disassembly, reducing the time and effort required, and eliminates the need to handle the heavy packing directly.

Implementation Method 1

an annular rod packing having an inner peripheral edge in sliding contact with the outer peripheral surface of the piston rod to prevent gas within the cylinder from leaking

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3517781B1Reciprocating compressor
Publication Date: 2021.01.06 KOBE STEEL LTD
  • EP3517781B1 patent drawingFigure 1
  • EP3517781B1 patent drawingFigure 2
  • EP3517781B1 patent drawingFigure 3A

AI summary

A reciprocating compressor with an easily replaceable rod packing is provided. This application discloses a reciprocating compressor including a piston rod coupled to a piston that is accommodated within a cylinder and a crank mechanism, and an annular rod packing having an inner peripheral edge in sliding contact with the outer peripheral surface of the piston rod to prevent gas within the cylinder from leaking around the outer peripheral surface of the piston rod. The piston rod includes a first rod portion with which the rod packing is in sliding contact and a second rod portion provided in a manner extending from the leading end of the first rod portion and inserted through an insertion hole that is formed in the piston. The piston is separable from the second rod portion. The diameter of the second rod portion is equal to or smaller than that of the first rod portion.