Multi-Stage Balancing Drum Assembly for Axial Force Compensation

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Solution Overview

Problem

Conventional centrifugal liquid pumps face inefficiencies due to axial forces that are not fully compensated by balancing drums, leading to increased power consumption, leakage, and reduced efficiency, as the clearance gaps allow process liquid to flow through, and production tolerances and component deviations exacerbate these issues.

Innovation Solution

A multi-stage balancing drum assembly with circumferential axial spaces and ring elements creates pressure chambers and flow paths to efficiently counteract axial forces, minimizing leakage and power consumption by using a multistage design with slide bearings for radial support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a balancing drum with clearance gap is used to compensate axial forces, then axial force compensation is improved, but process liquid flows through the gap causing efficiency decrease

Engineering Contradiction:

Improveaxial force compensationVSAvoidefficiency

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The balancing drum is divided into multiple drum sections (at least two) arranged axially, with circumferential axial spaces between them. This segmentation allows the creation of multiple pressure chambers that work together to compensate axial forces while reducing liquid leakage through the gaps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Ring elements are introduced as intermediary components that extend radially into the circumferential axial spaces between drum sections. These ring elements create additional flow restrictions and pressure chambers, acting as mediators to control liquid flow and enhance pressure distribution for better axial force compensation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Force

If a balancing drum is used to minimize axial forces, then thrust bearing load is reduced, but production tolerances and component deviations cause residual axial force

Engineering Contradiction:

Improvethrust bearing loadVSAvoidproduction tolerances

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The patent changes the hydraulic parameters by creating multiple pressure chambers with different pressure levels (first pressure chamber nearer to pump, second pressure chamber farther). This multi-pressure chamber configuration provides better compensation for manufacturing tolerances and component deviations, reducing residual axial force more effectively than a single-pressure chamber design.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single-stage balancing drum is used, then structure is simple, but axial force compensation is insufficient and residual force is high

Engineering Contradiction:

Improvebalancing drum structureVSAvoidresidual axial force

Core Design Contradiction:

Device complexityVSForce

Solution Approach 1:

The balancing drum is segmented into multiple drum sections with circumferential axial spaces between them, creating a multi-stage structure. This segmentation enables better axial force compensation by distributing the compensation function across multiple stages, reducing residual axial force while maintaining reasonable structural complexity.

Inventive Principle:

Principle #1Segmentation

4Loss of energy

If clearance gap is increased to reduce friction, then power loss decreases, but liquid leakage through gap increases

Engineering Contradiction:

Improvepower lossVSAvoidliquid leakage

Core Design Contradiction:

Loss of energyVSLoss of substance

Solution Approach 1:

Ring elements are positioned as intermediaries in the circumferential axial spaces, extending radially to create additional flow restrictions. These ring elements effectively reduce liquid leakage through the clearance gaps by creating pressure chambers that control the flow, while allowing the gaps to remain sufficiently large to minimize friction and power loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 assembly reduces the size of the balancing drum and shaft diameter while minimizing power loss and leakage, enhancing the efficiency and performance of multi-stage centrifugal liquid pumps.

Implementation Method 1

a first flow communication path from the stage of the pump nearest to the balancing drum to the second pressure chamber, and a second flow communication path from the stage of the pump farthest from the balancing drum to the first pressure chamber

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 2

minimizing power loss and leakage, enhancing the efficiency and performance of multi-stage centrifugal liquid pumps

Methodology Applied

Scientific EffectFluid film lubrication: Lubrication

Data Source

PatentUS12516674B1Multi-stage centrifugal pump comprising an assembly for compensating axial forces

Publication Date: 2026.01.06 SULZER MANAGEMENT AG

AI summary

A multi-stage centrifugal liquid pump includes a housing, impellers, and an assembly to compensate axial forces in the multi-stage centrifugal liquid pump. The assembly includes a shaft arranged rotatably to the housing, a balancing drum arranged to the shaft inside the housing, the balancing drum having a first axial end surface and a second axial end surface, the first axial end surface in flow communication with a stage of the pump adjacent to the balancing drum, the balancing drum being a multistage balancing drum, including at least two drum sections, and a circumferential axial space arranged between the at least two drum sections, the drum sections having a first radius.