Concrete Pump Cylinder Gap Seal for Low-Friction Service Life

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Solution Overview

Problem

Concrete pump cylinders experience premature wear and leakage due to high heat generation and friction in continuous operation, leading to reduced service life and performance issues.

Innovation Solution

A concrete pump cylinder seal system featuring a mechanical gap seal with a bronze-like coating and a floating design, optimized for reduced friction and defined leakage oil flow, including a primary seal between the piston rod and guide, and a secondary seal with a leakage line for oil drainage, along with damping elements for axial and radial play.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastomer seals are used in concrete pump cylinders, then sealing function is provided, but friction is high and service life is short

Engineering Contradiction:
Improveservice life of sealing systemVSAvoidfriction coefficient
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent replaces elastomer seals with a mechanical gap seal system consisting of a piston rod, guide, and adjustable gap seal. This mechanical substitution eliminates the high friction and heat generation associated with elastomer seals while providing effective sealing through a controlled gap between the piston rod and guide, significantly extending service life in continuous concrete pumping operations

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

Solution Approach 2:

The patent changes the sealing mechanism from contact-based elastomer seals to a gap-based mechanical seal with a specifically controlled clearance. By adjusting the gap parameter between the piston rod and guide, the system achieves optimal balance between sealing effectiveness and friction reduction, allowing continuous operation without premature wear

Inventive Principle:
Principle #35Parameter changes

2Productivity

If hydraulic drive operates in continuous operation, then concrete pumping productivity is maintained, but heat generation increases and wear accelerates

Engineering Contradiction:
Improveconcrete pumping flow rateVSAvoidheat generation in hydraulic system
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The mechanical gap seal system replaces the elastomer seal-based hydraulic cylinder, creating a sealing mechanism that generates minimal friction and heat. This allows the hydraulic drive to operate continuously at full productivity without the heat accumulation that previously caused premature wear and required shutdowns for cooling and maintenance

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

Solution Approach 2:

The patent acknowledges that some leakage is inevitable in mechanical gap seals but converts this potential harm into a benefit by implementing a leakage collection and recycling system. The controlled leakage through the gap actually reduces pressure buildup and heat generation, while the recycled oil maintains system productivity without the negative effects of complete sealing

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If a fixed gap seal is used, then sealing is provided, but friction increases and piston rod damage occurs

Engineering Contradiction:
Improvesealing effectivenessVSAvoidfriction between seal and piston rod
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent implements a floating gap seal design where the gap between the piston rod and guide can dynamically adjust based on operating conditions such as pressure and temperature. This dynamic adjustment maintains optimal sealing effectiveness while minimizing friction and preventing damage to the piston rod, unlike fixed gap seals that cannot adapt to changing conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing system is segmented into multiple components including the piston rod, guide, floating gap seal, and adjustment mechanism. This segmentation allows independent optimization of each component, with the gap seal specifically designed to maintain sealing function while minimizing contact and friction with the piston rod

Inventive Principle:
Principle #1Segmentation

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 mechanical gap seal system reduces wear, minimizes jerking, and extends the service life of the sealing system while maintaining optimal temperature behavior and performance, allowing for efficient concrete pumping with reduced heat generation and leakage.

Implementation Method 1

the service life of the sealing system and the temperature behavior are positively influenced by optimizing the friction of the sealing system

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the expected or required amount of leakage oil can be determined by appropriate selection or dimensioning of the gap seal

Methodology Applied
Scientific EffectFluid flow through gap: Pressure Gradient

Implementation Method 3

the interior of the primary seal is designed with a coating made of bronze or a bronze-like material. In this way, protection of a piston rod for a bearing of the concrete pump cylinder can advantageously be provided

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3642485B1Seal for a concrete pump cylinder
Publication Date: 2021.05.05 LIEBHERR COMPONENTS KIRCHDORF GMBH
  • EP3642485B1 patent drawingFigure 1a~1d
  • EP3642485B1 patent drawingFigure 2
  • EP3642485B1 patent drawingFigure 3

AI summary

The invention relates to a seal for a concrete pump cylinder having at least one primary seal and at least one secondary seal.