Split Ring Seal with Dynamic Throttle Gap

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Solution Overview

Problem

Existing centrifugal pump throttle gap designs face challenges in minimizing wear and ensuring high operational reliability while maintaining hydraulic efficiency, as they are either prone to significant wear or compromise on efficiency for reduced wear.

Innovation Solution

A U-shaped split ring design with a radial annular buffer filled with medium, which dynamically adjusts the gap between the rotor and stator, utilizing temperature-dependent material selection and hydrostatic damping to minimize friction and wear, and features an anti-twist device for stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a radial sealing gap is used with minimal axial displacement, then wear is minimized and operational reliability is high, but hydraulic efficiency decreases due to high loss coefficient

Engineering Contradiction:
Improveoperational reliabilityVSAvoidhydraulic efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The split ring is designed to be movable in the radial direction, transforming a static sealing gap into a dynamic one. The ring automatically adjusts its position based on operating conditions, allowing the system to achieve both low wear (when gap is larger) and high hydraulic efficiency (when gap is minimized) at different operational states.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the gap width parameter dynamically through the movable split ring design. By allowing the ring to move radially, the gap width becomes a variable parameter that can optimize both wear reduction and hydraulic efficiency under different operating conditions, rather than being fixed at a compromise value.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the throttle gap is minimized to reduce losses, then hydraulic efficiency increases, but wear increases and operational safety decreases

Engineering Contradiction:
Improvehydraulic efficiencyVSAvoidoperational safety
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The movable split ring creates a dynamic sealing system that can adapt to wear accumulation over time. Even when the gap is minimized for efficiency, the ring can move to maintain optimal clearance, preventing direct contact and seizure between rotor and stator components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The split ring performs self-adjustment through its movable design, automatically centering itself and maintaining optimal gap width without external intervention. This self-regulating capability ensures both high hydraulic efficiency and operational safety by preventing wear-induced seizure.

Inventive Principle:
Principle #25Self-service

3Reliability

If axial sealing gap is realized with axially displaceable components, then sealing is achieved, but wear is considerable

Engineering Contradiction:
Improvesealing capabilityVSAvoidwear
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The invention transitions from axial to radial displacement for sealing. The split ring moves radially to achieve sealing, which significantly reduces wear compared to axial displacement. The radial movement allows the ring to maintain sealing contact without the sliding friction inherent in axial displacement designs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention replaces the axial displacement mechanism with a radial displacement mechanism. By substituting the direction of movement from axial to radial, the system achieves equivalent sealing capability with dramatically reduced wear on the sealing surfaces.

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

4Reliability

If labyrinth structure is used for gap sealing, then sealing is achieved, but assembly and adjustment complexity increases significantly

Engineering Contradiction:
Improvesealing capabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The split ring is divided into two separable halves that can be assembled independently. This segmentation allows the ring to be installed without disassembling the entire pump, significantly simplifying assembly and maintenance compared to integral labyrinth structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable split ring design replaces complex adjustable mechanisms with a simple radial movement capability. The ring can be easily positioned and adjusted in the radial direction without requiring complex assembly procedures or specialized tools.

Inventive Principle:
Principle #15Dynamics

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 effectively minimizes wear, ensures high operational reliability, and maintains high hydraulic efficiency by dynamically regulating the gap and utilizing hydrostatic damping, preventing rotor-stator contact and reducing frictional forces.

Implementation Method 1

a radial annular space filled with medium is formed or enclosed by the present split ring. This radial annulus acts as a buffer

Methodology Applied
Scientific EffectHydrostatic damping: Hydraulic Accumulator

Implementation Method 2

the lubricating effect of the flowing medium in the throttle section on the split legs, which minimizes the friction during the centering process

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

with this fit being adjusted by a special material selection of the legs depending on the temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2906829B1Split ring having a self-regulating throttle gap
Publication Date: 2020.08.26 KSB SE & CO KGAA
  • EP2906829B1 patent drawingFigure 1
  • EP2906829B1 patent drawingFigure 2

AI summary

The invention relates to a sealing element as a split ring comprising a self-regulating throttle gap (6) for sealing a rotating component (1)against a stationary housing (2), wherein in the gap between the rotating component and the housing a split ring (7) is provided, wherein a ring space (4) filled with medium is formed on the stationary housing on a surface that is delimiting the gap in a radial manner, wherein the ring space is oriented such that the ring space is concentric in relation to the rotating component, wherein the ring space is enclosed by a split ring (7) that is designed in a U-shape, wherein between the U-shaped split ring (7) and the housing (2) an axial throttle gap and between the split ring (7) and the rotating component a radial gap which is filled with a medium and through which a medium flows, is provided.