Carbon-Coated Pressure Cover for Abrasion-Resistant Centrifugal Pumps

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Solution Overview

Problem

Centrifugal pumps face significant wear and tear due to abrasive media, leading to reduced functionality and short service life, especially when handling solids, and existing materials provide limited protection against wear and corrosion.

Innovation Solution

A centrifugal pump design featuring a pressure cover with a carbon layer, particularly a tetrahedral hydrogen-free amorphous carbon (ta-C) coating on contact surfaces, combined with a mechanical seal arrangement including an O-ring and counter ring, to enhance wear resistance and prevent damage to the shaft seal seat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If conventional materials (metal, rubber, plastic, enamel) are used for pump housing and pressure cover, then manufacturing costs are low and ease of manufacture is good, but wear resistance is insufficient and service life is reduced due to abrasion from solids-containing media

Engineering Contradiction:
Improveservice lifeVSAvoidabrasive wear
Core Design Contradiction:
Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies a diamond-like carbon (DLC) coating layer on the pressure cover surface, creating a composite structure that combines the mechanical strength of metal with the exceptional wear resistance of carbon. This composite approach resolves the contradiction by providing both durability and abrasion resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the surface properties of the pressure cover by applying a DLC coating, which fundamentally alters the surface hardness and friction characteristics. This parameter change enables the surface to withstand abrasive wear from solids-containing media while maintaining the base material's structural integrity.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If wear-resistant coatings are applied to the pressure cover, then wear resistance improves and service life extends, but manufacturing complexity increases and manufacturing costs rise

Engineering Contradiction:
Improvewear resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent replaces complex mechanical wear protection systems with a thin-film DLC coating applied through vapor deposition processes. This substitution simplifies the overall manufacturing approach while providing superior wear resistance compared to traditional thick coatings or mechanical hardening methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The DLC coating process operates at relatively low temperatures and can be applied in a single step, changing the deposition parameters to achieve thin, uniform layers. This reduces manufacturing complexity compared to traditional high-temperature heat treatment or multi-layer coating systems.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the pressure cover is made from corrosion-resistant non-metallic materials, then corrosion resistance improves, but strength and wear resistance are limited

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmaterial strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent creates a composite system where a metal pressure cover (providing strength) is coated with DLC (providing both corrosion and wear resistance). This composite approach overcomes the limitations of non-metallic materials by combining the advantages of different material classes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The DLC coating modifies the surface chemistry and physical properties of the metal pressure cover, providing corrosion resistance comparable to non-metallic materials while retaining the underlying metal's mechanical strength and structural properties.

Inventive Principle:
Principle #35Parameter changes

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 carbon layer significantly reduces abrasive wear, extends the service life of the pump, and maintains reliability while ensuring easy installation and low manufacturing costs, with the ta-C coating providing exceptional hardness and chemical resistance.

Implementation Method 1

The coating according to the invention protects the pressure cover component, particularly when pumping media containing solids, from abrasive action by the pumped medium

Methodology Applied
Scientific EffectAbrasion resistance: Abrasion

Implementation Method 2

The impeller shaft, which is provided with a shaft seal to prevent leakage, is guided into the pump interior by the pressure cover

Methodology Applied
Scientific EffectMechanical sealing:

Data Source

PatentEP3985258B1Centrifugal pump with a pump housing and a pressure cover
Publication Date: 2024.02.21 KSB SE & CO KGAA
  • EP3985258B1 patent drawingFigure 1
  • EP3985258B1 patent drawingFigure 2
  • EP3985258B1 patent drawingFigure 3

AI summary

The invention relates to a centrifugal pump with a pump housing (10) and a pressure cover (7). One surface of the pressure cover (7) has at least a partial carbon layer.