Magnetic Coupling Pump Axial Force Reduction

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Solution Overview

Problem

Conventional pumps with magnetic couplings face challenges in minimizing the axial force acting on the rotor shaft due to the necessary cooling requirements, which complicates the design and increases the risk of leakage.

Innovation Solution

The pump design connects the suction chamber directly to the containment shell via a line, allowing fluid to flow back and eliminating the need for a longitudinal bore in the rotor shaft, with the fluid cooling the magnetic coupling by flowing through openings in the cover and around the outside of the rotor, thereby reducing axial force and enhancing cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fluid is guided through a gap between the rotor shaft and cover to cool the magnetic coupling, then cooling is achieved, but significant axial force acts on the rotor shaft

Engineering Contradiction:
Improvecooling of magnetic couplingVSAvoidaxial force on rotor shaft
Core Design Contradiction:
TemperatureVSForce

Solution Approach 1:

The invention extracts the harmful axial force effect by removing the fluid passage through the rotor shaft gap. Instead of guiding fluid through the gap between rotor shaft and cover, the fluid is directed through a separate line connected to the suction chamber, completely eliminating the axial force while maintaining cooling function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary fluid line that connects the suction chamber to the containment shell, serving as a mediator to provide cooling flow without creating axial force on the rotor shaft. This separate fluid path acts as an intermediary mechanism that decouples the cooling function from the axial force problem.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If a longitudinal bore is provided in the rotor shaft for fluid flow, then cooling is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvecooling of magnetic couplingVSAvoidmanufacturing of rotor shaft
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention extracts the fluid passage function from the rotor shaft structure itself. By providing a separate fluid line connected to the suction chamber that directs fluid into the containment shell, the rotor shaft no longer requires a longitudinal bore, significantly simplifying its manufacturing while maintaining the cooling function.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If dynamic seals are used on the rotor shaft, then leakage is prevented, but maintenance is required due to wear

Engineering Contradiction:
Improvesealing of rotor shaftVSAvoidmaintenance of dynamic seals
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The invention replaces the mechanical dynamic seal system with a magnetic coupling system. The magnetic field transmits rotational motion from the external magnet to the internal magnet in the containment shell without physical contact, completely eliminating the need for dynamic seals and their associated wear and maintenance issues.

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

Solution Approach 2:

The magnetic field acts as an intermediary between the external and internal magnets, transmitting rotational motion without physical contact. This magnetic intermediary eliminates the need for mechanical seals at the rotor shaft, preventing leakage without requiring maintenance-prone dynamic seals.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stability of the object's composition

If robust bearings are used to absorb axial force, then rotor shaft stability is maintained, but device complexity increases

Engineering Contradiction:
Improvestability of rotor shaftVSAvoidbearing requirements
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention extracts the axial force generation from the cooling system design. By directing fluid through a separate line connected to the suction chamber rather than through the rotor shaft gap, the axial force is eliminated entirely, removing the need for robust bearings and simplifying the overall device structure while maintaining rotor shaft stability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 significantly reduces the axial force on the rotor shaft and provides effective cooling of the magnetic coupling, simplifying the manufacturing process and ensuring efficient heat dissipation without the need for dynamic seals.

Implementation Method 1

an internal magnet which can be set in rotation by the magnetic field of an external magnet

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Implementation Method 2

A leakage flow, driven by the pressure difference between the suction and pressure sides of the pump, is required to cool the magnetic coupling located in the containment shell

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP2322803B1Pump with a magnetic coupling
Publication Date: 2020.05.06 LEISTRITZ PUMPEN
  • EP2322803B1 patent drawingFigure 1~2

AI summary

The pump (13) has a magnetic clutch provided with a rotor shaft (15) that is rotatably supported by a pump housing (14). The rotor shaft is provided with an impeller or a spindle (16) for conveying fluid from a suction chamber (17) into a pressure chamber (18). A rotor (21) is provided with an inner magnet (22), which is set in rotation over a magnetic field of an outer magnet. The suction chamber and a slit pot (20) are connected with each other over a line (29) by the fluid. The rotor comprises openings distributed along circumferential direction.