Segmented Sensor Ring for Centrifugal Pump Axial Thrust

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Solution Overview

Problem

Conventional arrangements for absorbing axial thrust in centrifugal pumps face challenges such as significant leakage losses, limited structural space, and inability to detect faults early, leading to potential pump failure due to wear in bearings or inadequate relief device performance.

Innovation Solution

A segmented cardanic ring with multiple connected segments and strain sensors is used to distribute the axial force through multiple measurement points, allowing for precise measurement and early detection of faults while minimizing structural height and leakage losses, and enabling reliable absorption of axial thrust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional measurement device (ring) is used to measure axial force, then the force can be measured, but the structural height becomes too large and the device cannot be mounted in the limited pump space

Engineering Contradiction:

Improveaxial force measurementVSAvoidmeasurement device height

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The ring is divided into multiple segments (at least two) that are connected together. This segmentation allows the measurement function to be distributed across multiple smaller components, reducing the overall structural height while maintaining the ability to measure axial force through the cumulative deformation of all segments.

Inventive Principle:

Principle #1Segmentation

2Strength

If the ring is made stiffer to withstand large measuring forces, then the maximum force transmission capacity increases, but the structural height increases further

Engineering Contradiction:

Improvemaximum force transmissionVSAvoidmeasurement device height

Core Design Contradiction:

StrengthVSLength of stationary object

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Loss of energy

If gap width is minimized to reduce leakage losses, then energy efficiency improves, but the risk of rubbing between moving and stationary parts increases

Engineering Contradiction:

Improveleakage lossVSAvoidrisk of rubbing

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The measurement device provides real-time feedback on the axial thrust and operating conditions. This feedback enables monitoring of the gap status, allowing the system to detect when the gap is approaching dangerous levels that could cause rubbing, while maintaining minimal gap width for reduced leakage losses.

Inventive Principle:

Principle #23Feedback

4Reliability

If sensors are placed outside the pump casing for early fault detection, then measurement is possible, but internal faults (bearings, relief device) cannot be detected in early stages

Engineering Contradiction:

Improvefault detection capabilityVSAvoidsensor arrangement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The measurement device is integrated into the existing ring structure of the axial thrust absorption mechanism. This merging combines the force measurement function with the structural component already present in the pump, enabling internal fault detection without adding separate external sensors or increasing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 reliable early detection of faults, minimizes leakage losses, and ensures high reliability and service life with a compact design, allowing for efficient absorption of axial thrust and easy maintenance, while maintaining low production costs.

Implementation Method 1

The cardanic ring is dimensioned in such a way that it is deformed elastically by the residual thrust

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The individual segments of the ring are connected to one another and have a strain sensor each

Methodology Applied

Scientific EffectStrain measurement: Piezoresistive Effect

Data Source

PatentUS11536274B2Arrangement for receiving the axial thrust of a centrifugal pump

Publication Date: 2022.12.27 KSB SE & CO KGAA

AI summary

An arrangement for monitoring a centrifugal pump is provided. receiving the residual axial thrust of a centrifugal pump. The arrangement includes a load-relieving device configured to receive the residual axial thrust developed during pump operation, an axial bearing, and a sensor ring is associated with the axial bearing. The ring (10) is divided into segments having sensors at the segment dividing regions.