Magnetically Coupled Pump Assembly Using Ferrous Rotor

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Solution Overview

Problem

Conventional respiratory care products using rare earth magnets in disposable cartridges are expensive due to the high cost of these magnets, necessitating a cost-effective alternative for the disposable pump units in respiratory care systems.

Innovation Solution

A magnetically coupled pump assembly with a permanent stator unit and a disposable rotor unit made of ferrous metal elements, such as magnetic stainless steel, molded with plastic, which reduces the cost by using a ring magnet in the stator unit to induce rotation of the ferrous metal elements, thereby reducing the expense of the disposable cartridge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If rare earth magnets are used in the disposable cartridge to activate the impeller, then the pump unit can be separated into disposable and reusable portions, but the disposable cartridge becomes expensive

Engineering Contradiction:

Improveseparation between disposable cartridge and reusable capital unitVSAvoidcost of disposable cartridge

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive rare earth magnets in the disposable cartridge with inexpensive ferrous metal elements (such as steel balls or ferrous powder) that can be easily molded into the rotor unit. These cheap ferrous elements are magnetically coupled to the impeller by a permanent magnet in the reusable capital unit, enabling the disposable cartridge to be manufactured at low cost while maintaining the separation between disposable and reusable portions.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes the mechanical magnetic coupling system (using rare earth magnets) with a magnetic field-based system where a permanent magnet in the reusable unit magnetically attracts ferrous metal elements in the disposable rotor unit. This substitution eliminates the need for expensive magnets in the disposable portion while maintaining the magnetic coupling necessary for impeller rotation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If ferrous metal elements are used instead of rare earth magnets, then the cost of the disposable cartridge is reduced, but the magnetic coupling strength may be weakened

Engineering Contradiction:

Improvecost of disposable cartridgeVSAvoidmagnetic coupling strength

Core Design Contradiction:

Ease of manufactureVSForce

Solution Approach 1:

The patent optimizes parameters such as the size, shape, and distribution of ferrous metal elements within the rotor unit to maximize magnetic coupling strength. By carefully controlling the volume fraction, particle size distribution, and spatial arrangement of the ferrous elements, the system achieves sufficient magnetic attraction force from the permanent magnet in the reusable unit to effectively rotate the impeller, despite using cheaper materials.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The rotor unit is constructed as a composite material system combining ferrous metal elements (such as steel balls or ferrous powder) with a plastic or polymer matrix. This composite structure provides both the necessary magnetic responsiveness to the permanent magnet's field and the mechanical integrity required for the disposable cartridge, achieving a balance between cost reduction and functional performance.

Inventive Principle:

Principle #40Composite materials

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

The use of ferrous metal elements in the disposable rotor unit significantly lowers the cost of the pump assembly while maintaining the necessary magnetic coupling for effective water pumping, ensuring sterility and reusability of the system components.

Implementation Method 1

The rotor unit and the impeller are positioned inside the first cup and rotatable around the shaft... a ring magnet in the stator unit to induce rotation of the ferrous metal elements

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

Activation of the rare earth magnets can cause rotation of an impeller in the disposable cartridge to pump the water through the fluid circuit

Methodology Applied

Scientific EffectMagnetic induction: Electromagnetic Induction

Data Source

PatentUS10260507B2Magnetically coupled pump assembly

Publication Date: 2019.04.16 MOOG INC

AI summary

Embodiments of the invention provide a pump assembly including a pump chamber with an inlet and an outlet. The pump assembly also includes a first cup at least partially enclosing the pump chamber and including a protrusion with a central recess, and a shaft positioned within the central recess. The pump assembly further includes a substantially hemispherical rotor unit with at least one ferrous metal element molded in plastic, and an impeller coupled to the rotor unit. The rotor unit and the impeller are positioned inside the first cup and rotatable around the shaft.