Orbital Pump Rotor Positioning via Absolute Angle Detection

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Solution Overview

Problem

Existing pumps, particularly orbital pumps, face issues with open-loop operation leading to rotor misalignment, increased wear, and fluid delivery variance due to low resolution rotor sensors, resulting in unpredictable stopping positions and potential leaks when switched off, which complicates fluid measurement and increases maintenance costs.

Innovation Solution

A pump system with a rotor sensor for absolute angle detection and a pump controller that precisely positions the rotor shaft, allowing for controlled operation and calibration, reducing metering variance, preventing leaks, and optimizing start-up currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If open-loop operation is used with low resolution rotor sensors, then the pump structure remains simple, but the rotor positioning precision deteriorates and metering variance increases

Engineering Contradiction:
Improvepump structureVSAvoidrotor positioning precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical open-loop control with an electronic closed-loop control system. The controller continuously monitors the actual rotor angle via the rotor sensor and compares it with the target angle, then adjusts the motor drive signals accordingly. This substitution of mechanical positioning with electronic feedback control achieves precise rotor positioning without requiring overly complex mechanical structures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a closed-loop feedback control system where the rotor sensor detects the actual rotor angle and feeds this information back to the controller. The controller uses this feedback to calculate the angle deviation and generate corrective drive signals for the motor, ensuring the rotor reaches and maintains the target position accurately. This feedback mechanism resolves the contradiction by enabling precise positioning through intelligent control rather than mechanical complexity.

Inventive Principle:
Principle #23Feedback

2Device complexity

If the rotor is allowed to follow the magnetic field in open-loop operation, then the control system remains simple, but the rotor lags behind the magnetic field under increased load causing volume flow calculation to become impossible

Engineering Contradiction:
Improvecontrol systemVSAvoidvolume flow measurement reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs a closed-loop feedback control system where the rotor sensor continuously provides actual rotor angle information to the controller. This feedback enables the controller to calculate the precise angle deviation between the target and actual rotor positions, allowing accurate volume flow calculation regardless of load conditions. The system actively compensates for rotor lag by adjusting motor drive signals based on real-time rotor position data.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary positioning of the rotor to a specific target angle before fluid delivery. The controller calculates the required rotation angle in advance and drives the motor to position the rotor precisely at the target angle, ensuring accurate metering from the start of each pumping cycle. This preliminary positioning action eliminates the accumulation of positioning errors that would otherwise occur under varying load conditions.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the rotor shaft is not precisely positioned, then the pump operation remains simple, but undefined overshooting occurs around the target position increasing wear on elastic elements

Engineering Contradiction:
Improvepositioning controlVSAvoidservice life of elastic elements
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a closed-loop feedback control system where the rotor sensor provides continuous position feedback to the controller. As the rotor approaches the target angle, the controller receives feedback signals and progressively reduces motor drive power to minimize overshooting. This feedback-based deceleration control allows the rotor to smoothly settle at the target position without excessive oscillation or impact, thereby protecting elastic elements like diaphragms from increased wear.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements beforehand cushioning by having the controller progressively reduce motor drive power as the rotor approaches the target angle. This anticipatory reduction in driving force acts as a cushion against potential overshooting and impact loads. The controller calculates the remaining angle deviation and adjusts the drive signals accordingly, preventing the rotor from overshooting the target position and thereby protecting elastic components from excessive mechanical stress and wear.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Device complexity

If the pump operates without absolute rotor position detection, then the system remains simple, but leakage flow through the pump cannot be detected when switched off

Engineering Contradiction:
Improvedetection systemVSAvoidleakage detection capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs an absolute rotor position detection system that provides feedback on the rotor's angular position even when the pump is switched off. The rotor sensor continuously monitors the rotor angle and reports it to the controller, enabling the system to detect any unintended rotor movement that would indicate internal leakage. This feedback mechanism allows the pump to distinguish between normal operational positions and positions indicating leakage, thereby enhancing reliability without significantly increasing system complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3768974B1Pump with detection of absolute angle of rotation
Publication Date: 2023.08.30 EBM PAPST ST GEORGEN GMBH & CO KG
  • EP3768974B1 patent drawingFigure 1

AI summary

The invention relates to an orbital pump for pumping a fluid, wherein the pump comprises at least one pump control system, a motor that can be controlled by the pump control system, a rotor shaft (10) for fluid transport, and a rotor sensor for detecting an absolute angle of rotation of the rotor shaft (40), the rotor sensor is connected to the pump control system and designed to transmit the angle of rotation of the rotor shaft (40) to the pump control system, and the pump control system is designed to rotationally control the rotor shaft (40) by means of the motor until the rotor shaft (40) is in a pre-determined angle of rotation position.