Liquid Chromatography Pump Seal Wear Reduction

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Solution Overview

Problem

High-pressure seals in liquid chromatography pumps experience significant wear due to pressure cycling, leading to leaks and reduced operational lifetime, especially when using solvents like water and trifluoroacetic acid.

Innovation Solution

A wear-resistant coating, such as diamond-like carbon (DLC) or titanium, is applied to the sealing surface of the pump head where the high-pressure seal assembly abuts, reducing surface wear and extending the seal assembly's lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high-pressure seal is used in a reciprocating pump, then sealing effectiveness is improved, but seal wear increases due to pressure cycling

Engineering Contradiction:

Improvesealing effectivenessVSAvoidseal assembly lifetime

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies a diamond-like carbon (DLC) coating to the sealing surface of the pump head. This creates a composite structure where the base material (metal sealing surface) provides structural integrity while the DLC coating provides wear resistance and chemical inertness. The coating layer protects the seal assembly from wear during pressure cycling, thereby extending its operational lifetime while maintaining sealing effectiveness.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the surface properties of the sealing surface by applying a DLC coating. This modifies parameters such as surface hardness, friction coefficient, and chemical compatibility. The coated surface has higher hardness and lower friction compared to the uncoated surface, which reduces wear on the seal assembly during reciprocating motion and pressure cycling.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If a wear-resistant coating is applied to the sealing surface, then seal wear is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improveseal assembly lifetimeVSAvoidsealing surface manufacturing

Core Design Contradiction:

Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The DLC coating is applied only to the specific sealing surface area where wear occurs, rather than coating the entire pump head. This localized application maintains the base material properties in non-critical areas while providing enhanced wear resistance only where needed, thus minimizing the impact on manufacturing complexity.

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

The wear-resistant coating substantially limits surface wear, enhancing the hardness and chemical compatibility of the sealing surface, thereby reducing leakage and extending the operational lifetime of the seal assembly.

Implementation Method 1

Methodology Applied

Scientific EffectWear-resistant coating: Coatings

Data Source

PatentEP2702271B1High pressure pump with reduced seal wear

Publication Date: 2020.02.12 WATERS TECHNOLOGY CORP

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AI summary

Described are embodiments of a pump that can be used, for example, in liquid chromatography applications. The pump includes a seal wash housing, pump head and seal assembly. A wear-resistant coating applied to a sealing surface or gland of the pump head or seal wash housing improves the hardness and chemical compatibility of the sealing surface. Oxidation of the sealing surface is reduced so that the sealing surface is less abrasive to the seal assembly and the lifetime of the seal assembly is increased.