Radial Magnetic Coupling Non-Conductive Canister Eddy Current Reduction
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Solution Overview
Problem
Radial magnetic couplings in rotary devices face issues with energy loss due to eddy currents in conductive canisters and increased radial gaps that reduce torque, as well as challenges in supporting rotors without increasing axial space or deflection.
Innovation Solution
A rotary device design featuring a multi-piece stationary canister with a non-conductive cylindrical portion and a bushing that serves as both a radial and axial bearing, eliminating eddy currents and minimizing the magnet gap for maximum torque, while being compact and easy to assemble.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conductive canister is used to separate the magnets, then structural strength and electrical conductivity are improved, but eddy currents are generated causing energy loss
Solution Approach 1:
The canister is constructed from non-conductive composite materials such as fiber-reinforced plastics (e.g., fiberglass, carbon fiber composites) or ceramic materials. These composite materials provide the necessary structural strength to contain the fluid chamber while being electrically non-conductive, thereby eliminating eddy current generation and the associated energy losses.
2Length of stationary object
If the radial gap between magnets is increased to accommodate a canister, then separation and fluid containment are improved, but torque is reduced
Solution Approach 1:
The patent optimizes the canister wall thickness to achieve the minimum necessary separation for fluid containment while minimizing the impact on torque. By carefully controlling the thickness parameter and using high-strength non-conductive materials, the design achieves an optimal balance between fluid sealing requirements and magnetic coupling efficiency.
3Adaptability or versatility
If traditional separate bearing and canister components are used, then functional separation is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The bearing function is integrated directly into the canister structure. The canister incorporates radial and axial bearing surfaces that provide rotor support, eliminating the need for separate bearing components. This merging of functions reduces the total number of parts, simplifies assembly, and maintains all necessary functional separations for fluid containment and magnetic coupling.
4Reliability
If axial space is increased to accommodate traditional bearing arrangements, then rotor support is improved, but compactness is reduced
Solution Approach 1:
The bearing surfaces are arranged in a compact configuration within the radial and axial dimensions of the canister. By utilizing the canister's cylindrical geometry and positioning bearing surfaces at strategic locations (radial surfaces for radial support, axial surfaces for axial support), the design provides adequate rotor support without increasing the overall axial length of the device.
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 design reduces energy loss, increases torque, and enhances the structural integrity and ease of assembly by using a non-conductive canister and a bushing that provides both radial and axial support, resulting in a more efficient and robust rotary device.
Implementation Method 1
Permanent magnet coupled pumps generally utilize end suction via an axial inlet, are of single stage or multistage configuration, and may include an overhung impeller design. The drive section utilizes permanent magnets or an eddy current drive system to transmit power to the impeller.
Implementation Method 2
Radial magnetic couplings that utilize permanent magnets are common, for example, in rotodynamic (also known as kinetic or centrifugal) pumps. The radial magnetic couplings consist of three main components: a larger, outer coupling component (also known as an outer magnet ring or outer rotor) with multiple permanent magnets on its inner surface
Implementation Method 3
a bushing that serves three purposes, a stationary canister that serves three purposes, the stationary canister being made of two separate parts including a substantially cylindrical portion and a canister end cap portion
Data Source
AI summary
Rotary devices having a casing and an inner drive portion of a magnet coupling disposed inside of a rotor assembly are disclosed. The inner drive portion and rotor assembly are disposed within the casing and rotatable about a rotational axis. The rotor assembly includes a bushing between the magnets of the rotor assembly and a stationary canister is sealed to the casing and separates an internal fluid chamber within the casing from the inner driven portion. The stationary canister can be of multi-piece or unitary construction and is held in position by a front portion of the casing.