Pump Bearing Arrangement for Flow Rate Detection Without Flowmeters
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Solution Overview
Problem
Flowmeters at the output of pumps are expensive, require assembly and space, and are not suitable for measuring high flow rates, especially in double volute centrifugal pumps where radial loads balance out, preventing effective measurement.
Innovation Solution
A bearing arrangement with rolling bearings supporting the impeller shaft, equipped with sensors to measure axial forces and revolution speed, and a method to determine volumetric liquid flow rate using relationship data between these parameters, eliminating the need for flowmeters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flowmeters are installed at the output of the pump to measure volumetric liquid flow rate, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the measurement function from a separate flowmeter component and integrates it into the existing bearing structure. The bearing arrangement now serves dual purposes: mechanical support and flow rate measurement through axial force sensing, thereby eliminating the need for additional flowmeter components while maintaining measurement capability
Solution Approach 2:
The invention merges the flow measurement function with the bearing structure. The bearing arrangement is designed to simultaneously support the impeller shaft mechanically and sense axial forces that correlate with volumetric liquid flow rate, combining two previously separate functions into a single integrated component
2Measurement precision
If flowmeters are installed to measure high flow rates, then measurement capability is improved, but cost increases significantly
Solution Approach 1:
The bearing structure serves itself by performing both its mechanical support function and the flow measurement function. The axial force measurement capability inherent in the bearing design is utilized to determine volumetric liquid flow rate, eliminating the need for expensive specialized flowmeters capable of measuring high flow rates
3Measurement precision
If flowmeters are installed at the pump output, then flow rate measurement is enabled, but assembly requirements and space needs increase
Solution Approach 1:
The invention combines the flow measurement functionality with the bearing assembly that is already part of the pump structure. Since the bearing must be installed anyway for mechanical support, integrating the measurement function into this existing component eliminates additional assembly steps and space requirements that would be needed for a separate flowmeter
4Measurement precision
If radial load measurement is used to determine operation condition, then flow rate determination is enabled, but the method fails for double volute pumps where radial loads balance out
Solution Approach 1:
The invention changes the measurement parameter from radial load to axial force. While radial loads balance out in double volute pumps making them unsuitable for measurement, axial forces do not balance and remain correlated with volumetric liquid flow rate across different pump types, including both single and double volute configurations
Solution Approach 2:
Instead of measuring radial forces as disclosed in prior art, the invention inverts the approach by measuring axial forces on the impeller shaft. This alternative measurement direction provides reliable flow rate determination for double volute pumps where radial force measurement would fail due to load balancing
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
Enables accurate determination of volumetric liquid flow rate without flowmeters, simplifying maintenance and design, applicable to various centrifugal pumps, and detecting operational issues like cavitation.
Implementation Method 1
the measuring means comprise a sensor measuring axial forces acting on the impeller shaft, particularly comprising at least one optical fiber, particularly comprising at least one fiber Bragg grating
Data Source
AI summary
A bearing arrangement of a centrifugal pump includes at least one rolling-element bearing configured to support an impeller shaft of the centrifugal pump and to support an axial load, an axial force sensor configured to measure a present axial force acting on the impeller shaft, a rotation speed sensor configured to measure a present rotation speed of the impeller shaft, a memory storing relationship data between each of a plurality of known volumetric flow rates at a plurality of known rotation speeds of the impeller shaft and a plurality of known axial forces acting on the impeller shaft, and a controller configured to determine a present volumetric flow rate through the centrifugal pump from the relationship data and the measured present axial force and the measured present rotation speed.