Adjustable Suction Neck Wear Ring for Low-Loss Centrifugal Pumps

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Solution Overview

Problem

Centrifugal pumps with split-case designs face inefficiencies due to hydraulic bypass and high maintenance requirements, particularly in large pumps where the radial seal between the impeller and the pump housing wears out, leading to reduced efficiency and prolonged downtimes for maintenance.

Innovation Solution

A centrifugal pump with a slotted wear ring and an adjustable suction neck seal, allowing for precise adjustment of the sealing gap without disassembly, using a circular wedge connection and actuating mechanism to maintain minimal gap sizes and reduce maintenance efforts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a wear ring is used to seal the suction neck radially, then the hydraulic efficiency is improved by minimizing the gap, but the maintenance complexity increases due to wear requiring regular replacement

Engineering Contradiction:
Improvehydraulic efficiencyVSAvoidmaintenance complexity
Core Design Contradiction:
Loss of energyVSEase of repair

Solution Approach 1:

The wear ring is designed with a slot that allows it to be dynamically adjusted in diameter. The adjustment unit enables the wear ring to be tightened or loosened in the circumferential direction, changing its inner diameter to compensate for wear. This dynamic adjustment capability allows the seal gap to be optimized throughout the service life of the wear ring, eliminating the need for replacement while maintaining hydraulic efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of the wear ring's inner diameter through the adjustment unit. By applying circumferential forces via the adjustment unit, the inner diameter of the wear ring can be varied to compensate for wear-induced gap increases. This parameter change allows continuous optimization of the seal gap without replacing the wear ring.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the wear ring is made larger to reduce manufacturing tolerances, then the assembly ease is improved, but the device complexity increases due to the adjustment mechanism

Engineering Contradiction:
Improveassembly easeVSAvoiddevice complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The wear ring is segmented by introducing a slot, which divides the continuous ring into two separable ends. This segmentation allows the wear ring to be adjusted in diameter by moving the ends relative to each other along the slot. The segmentation enables the adjustment function while keeping the overall structure relatively simple and manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adjustment unit acts as an intermediary mechanism between the operator and the wear ring. It provides a controlled means to apply circumferential forces to the wear ring, enabling precise diameter adjustment without requiring complex direct manipulation of the wear ring itself. This intermediary simplifies the user interface while achieving the desired adjustment capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If the sealing gap is minimized during assembly, then the hydraulic efficiency is improved, but the reliability decreases due to shaft bending and gap increase over time

Engineering Contradiction:
Improvehydraulic efficiencyVSAvoidsealing reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The adjustment unit provides a feedback mechanism that allows monitoring and correction of the seal gap. As the wear ring wears and the gap increases, the adjustment unit enables the operator to detect this change and adjust the wear ring accordingly to restore the optimal gap. This feedback loop maintains sealing reliability and hydraulic efficiency throughout the service life.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention incorporates preliminary adjustment capability during assembly to establish the optimal initial gap. The adjustment unit allows the wear ring to be precisely positioned before operation begins, ensuring minimal initial gap for high hydraulic efficiency. This preliminary action sets the foundation for long-term reliability.

Inventive Principle:
Principle #10Preliminary action

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 enables lower gap losses, higher efficiency, and reduced maintenance times by allowing for in-situ adjustment of the sealing gap, minimizing the need for wear ring replacement and reducing downtimes, while maintaining precise sealing even as components wear.

Implementation Method 1

between the outer ring and the inner ring, wherein the outer ring is angularly adjustable relative to the inner ring in the circumferential direction, wherein the inner ring has a circular wedge profile on its outer circumference

Methodology Applied
Scientific EffectWedge: Wedge

Data Source

PatentEP3467319B1Centrifugal pump with improved suction neck seal
Publication Date: 2022.03.30 WILO SE
  • EP3467319B1 patent drawingFigure 1
  • EP3467319B1 patent drawingFigure 2
  • EP3467319B1 patent drawingFigure 3~5

AI summary

Centrifugal pump (50) with a pump housing (1, 1a, 1b) and at least one impeller (2) arranged therein for pumping a liquid, which has a suction neck (10a) which is sealed radially to the pump housing (1, 1a, 1b) by a wear ring (14), characterized in that the wear ring (14) is slotted and the pump housing (1, 1a, 1b) has an adjusting unit (15, 21) by means of which the diameter of the wear ring (14) can be adjusted.