Centrifugal Pump Sealing Gap with Rotating Bodies for Low Leakage

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Solution Overview

Problem

Centrifugal pumps face challenges in maintaining a small gap between rotating and non-rotating elements to minimize efficiency losses while preventing wear and leakage, which is difficult due to manufacturing tolerances and operational influences.

Innovation Solution

The design incorporates rotatably mounted bodies, such as balls or cylinders, within a structure that allows them to protrude into the sealing gap, preventing wear by converting frictional forces into rotational movements and maintaining a small gap width to minimize leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the gap between rotating and non-rotating elements is reduced to minimize leakage and提高效率, then pump efficiency is improved, but the risk of contact and wear increases due to manufacturing tolerances and operational influences

Engineering Contradiction:
Improveleakage lossVSAvoidwear prevention
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent introduces elastic elements as intermediary components between the rotating and non-rotating elements. These elastic elements act as a mediator that absorbs dimensional variations and prevents direct contact between the sealing surfaces, thereby maintaining a reliable seal while preventing wear and damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state and properties of the sealing system by introducing elasticity through elastic elements. This parameter change allows the sealing system to adapt to dimensional variations dynamically, maintaining optimal gap conditions for minimizing leakage while preventing contact under varying operational conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If elastic elements are introduced to prevent damage to the rotating part, then reliability is improved, but the gap width increases leading to higher leakage and reduced efficiency

Engineering Contradiction:
Improvedamage preventionVSAvoidleakage loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies partial action by using elastic elements only where and to the extent necessary for preventing damage, rather than throughout the entire sealing interface. This selective application minimizes the impact on gap width and leakage while providing sufficient protection against damage.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent employs elastic elements that function as flexible components between rigid sealing surfaces. These flexible elements deform elastically to accommodate dimensional variations without significantly increasing the overall gap width, thus balancing damage prevention with leakage control.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a minimum gap width is maintained to prevent contact and wear, then reliability is improved, but leakage losses increase and pump efficiency decreases

Engineering Contradiction:
Improvewear preventionVSAvoidpump efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent transforms the static gap into a dynamic system by incorporating elastic elements that can deform and adapt to changing operational conditions. This dynamic capability allows the system to maintain optimal gap conditions automatically, preventing wear during normal operation while minimizing leakage losses.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic elements provide self-adjusting functionality, automatically compensating for dimensional variations and maintaining optimal gap conditions without external intervention. This self-service mechanism ensures continuous optimal performance in terms of both wear prevention and efficiency.

Inventive Principle:
Principle #25Self-service

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

This approach effectively reduces leakage and wear, enhancing the centrifugal pump's efficiency and service life while minimizing maintenance and operational costs.

Implementation Method 1

preventing wear by converting frictional forces into rotational movements

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The gap formed between the rotating and non-rotating elements acts as a throttle between the chambers of differing pressures, preventing excessive flow from the higher-pressure chamber to the lower-pressure chamber

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Data Source

PatentEP3452728B1Centrifugal pump having an arrangement for sealing
Publication Date: 2022.03.16 KSB SE & CO KGAA
  • EP3452728B1 patent drawingFigure 1
  • EP3452728B1 patent drawingFigure 2
  • EP3452728B1 patent drawingFigure 3

AI summary

The invention relates to a centrifugal pump having an arrangement (6) for sealing. A gap (S) is formed between a rotating element (10) and a non-rotating element (9). At least one element (9, 10) has bodies (11) which are movably mounted.