Centrifugal Pump Turbine Wheel Flow Measurement
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Solution Overview
Problem
Centrifugal pumps face challenges in accurately detecting delivery flow due to measurement inaccuracies caused by bearing friction and solid matter interference, especially at lower speeds and delivery powers.
Innovation Solution
A centrifugal pump design featuring a turbine wheel that is not rotationally coupled to the pump shaft, acting as a flow transducer, with blading configured to counteract torque from the delivery flow, allowing for accurate flow measurement by generating a measurement signal proportional to the delivery flow, and utilizing sensors to determine rotation speed and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a turbine wheel is used as a flow transducer, then flow measurement capability is improved, but bearing friction and solid matter interference cause measurement inaccuracies
Solution Approach 1:
The patent extracts the turbine wheel from the pump shaft's rotational system, allowing it to rotate independently without being coupled to the pump shaft. This separation eliminates the harmful effects of bearing friction and solid matter interference that would otherwise affect measurements, while still enabling accurate flow detection through the turbine wheel's independent rotation response to fluid torque.
Solution Approach 2:
The turbine wheel acts as an intermediary element between the fluid flow and the measurement system. It converts the fluid's torque into rotational motion that can be measured by sensors, providing an indirect but accurate measurement of flow conditions without the measurement system directly interfering with the flow or being affected by friction and debris.
2Device complexity
If the turbine wheel is rotationally coupled to the pump shaft, then structural simplicity is improved, but measurement accuracy deteriorates due to friction and interference
Solution Approach 1:
The patent segments the rotational system into two independent parts: the pump shaft driven by the motor and the turbine wheel responding to fluid flow. This segmentation allows each component to perform its specific function without interfering with the other, maintaining structural simplicity while eliminating the measurement errors caused by coupling friction and solid matter interference.
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 design enables accurate detection of delivery flow even at low delivery powers, reducing measurement inaccuracies and improving overall flow measurement accuracy, while maintaining a cost-effective construction.
Implementation Method 1
turbine wheel blading configured such that a torque exerted by the delivery flow onto the turbine wheel is directed counter to a torque exerted via the pump shaft onto the impeller
Data Source
AI summary
A centrifugal pump includes at least one pump stage (14). This pump stage (14) includes an impeller (18) which is mounted rotationally fixed on a pump shaft (26). Apart from the pump stage (14), the centrifugal pump is equipped with a turbine wheel (32) which is arranged on the pump shaft (26), without a movement coupling to the pump shaft, in the delivery flow of the centrifugal pump. This turbine wheel (32) forms a transducer of a flow measuring device. A blading of the turbine wheel (32) is such that a torque exerted by the delivery flow onto the turbine wheel (32′) is directed counter to a torque exerted via the pump shaft (26) onto the impeller (18).