Circulation Pump Dry Running Detection via Power Analysis
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Solution Overview
Problem
Circulating pump units face challenges in detecting dry running without additional sensors, which can lead to damage from prolonged dry operation of slide bearings lubricated by pumped liquids.
Innovation Solution
Incorporating an electronic control device with fluid identification functions that rotate the drive motor at different speeds or directions to record power consumption, allowing for the evaluation of fluid properties and distinguishing between liquid and gas, and using a ratio of power consumptions to detect dry running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional sensors are installed to detect dry running, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The pump unit uses its own existing components (drive motor, power consumption measurement capability) to detect dry running conditions. The control device evaluates power consumption at different rotational speeds to determine fluid presence, eliminating the need for external sensors and making the system self-diagnostic.
Solution Approach 2:
The patent replaces potential mechanical or electrical contact-based sensing methods with a field-based measurement approach. By measuring electrical power consumption and analyzing it through control logic, the system detects dry running without physical contact sensors, reducing complexity while maintaining reliability.
2Device complexity
If power consumption is measured at a single operating speed, then measurement simplicity is improved, but detection accuracy deteriorates
Solution Approach 1:
The control device dynamically adjusts the rotational speed of the drive motor during the detection process. By measuring power consumption at multiple different speeds, the system captures the dynamic relationship between speed and power, which provides characteristic signatures that enable accurate differentiation between liquid and gas states.
Solution Approach 2:
The patent changes the operating parameter (rotational speed) during measurement to obtain multiple data points. By analyzing how power consumption varies with speed, the system can distinguish between different fluid conditions more accurately than a single static measurement would allow.
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 reliable detection of dry running and fluid properties, preventing damage to bearings by accurately identifying the presence of liquid and distinguishing between different fluids and viscosities, thus ensuring safe operation.
Implementation Method 1
The electrical power consumption is recorded by the control device in each instance. Subsequently, based on the recorded power consumption at the different speeds or directions of rotation, the control device performs an evaluation to detect at least one property of the fluid in the impeller.
Implementation Method 2
the drive motor has a rotor which is mounted in plain bearings which are lubricated by a fluid pumped by the circulating pump unit
Data Source
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AI summary
The invention relates to a circulating pump unit with an electric drive motor (10, 16), at least one impeller (6) driven by the electric drive motor (10, 16), and an electronic control unit which controls the drive motor (10, 16), wherein the control unit (22) has at least a first fluid detection function (a1) in which the control unit (22) controls the drive motor (10, 16) such that it rotates successively at at least two different speeds or in different directions of rotation (CW, CCW), wherein the control unit (22) detects the electrical power consumption (P) in each case and, based on an evaluation of the detected electrical power consumption (P) for the different speeds or directions of rotation (CW, CCW), detects at least one property of the fluid in the impeller (6), and a method for operating such a circulating pump unit.