Packing Cup Fatigue Life via Alloy Composition
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Solution Overview
Problem
Reciprocating compressors, particularly hyper compressors used in polymer and copolymer production, face frequent fatigue-related failures in packing cups due to high operating pressures and pressure fluctuations, leading to reduced reliability and operational life.
Innovation Solution
The packing cups are made from a high-strength metallic alloy with a specific chemical composition (C: 0.13-0.17%, Cr: 1.80-2.20%, Ni: 9.50-10.50%, Co: 13.50-14.50%, Mo: 0.90-1.10%, Al: 0.015% max, Ti: 0.015% max, Mn: 0.10% max, Si: 0.10% max, S: 0.005% max, P: 0.008% max) that undergoes vacuum induction melting, vacuum arc remelting, and heat treatment to enhance mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional low alloy steel alloys are used for packing cups, then manufacturing cost is reduced, but fatigue life and reliability are insufficient under high pressure conditions
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the steel alloy (specific ranges of C, Cr, Ni, Co, Mo, Al, Ti, Mn, Si, S, and P) to achieve optimal mechanical properties for high fatigue resistance while maintaining manufacturability through standardized metallurgical processes
Solution Approach 2:
The patent creates a composite material system by combining multiple alloying elements in specific proportions to produce a high-strength steel alloy that exhibits superior fatigue properties, effectively creating a new material class optimized for compressor packing cup applications
2Strength
If autofrettage and shot peening treatments are applied to increase strength, then wear resistance improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the material composition parameters to inherently provide high fatigue strength, eliminating the need for additional surface treatment processes like autofrettage and shot peening, thereby reducing manufacturing complexity while maintaining or improving strength properties
3Power
If packing cups are subjected to high fatigue loads from pressure fluctuations, then compression performance is maintained, but crack formation and breakage occur
Solution Approach 1:
The patent optimizes the chemical composition parameters of the steel alloy, specifically enhancing the content of fatigue-resistant elements like Ni, Cr, and Mo while controlling carbon content, to achieve a material that can withstand high compression loads without developing fatigue cracks
Solution Approach 2:
The patent develops a composite steel alloy material with a specific multi-element composition that provides both the strength needed for high-pressure compression and the toughness required to resist fatigue crack propagation under cyclic loading 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
The solution significantly increases the reliability and fatigue life of packing cups by over 40% compared to conventional materials, reducing maintenance needs and production downtime.
Implementation Method 1
The metallic alloy undergoes vacuum induction melting
Implementation Method 2
vacuum arc remelting
Implementation Method 3
heat treatment to enhance mechanical properties
Data Source
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AI summary
The invention describes a packing cup (22) for the cylinder (10) of a reciprocating compressor. The packing cup (22) is formed from a first outer disc (28) and from a second inner disc (30), concentric to the first outer disc (28) and inside which a seat is formed for at least one sealing element for the piston (18). At least a part of the packing cup (22) is manufactured from a high- strength metallic alloy, obtained through a melting process and subsequent plastic deformation. The material is finally subjected to special heat treatments to improve the overall mechanical properties of the packing cup (22).