Magnetically Levitated Centrifugal Pump Inlet Lip for Leakage Control
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Solution Overview
Problem
Centrifugal pumps with magnetically levitated rotors experience high leakage flow and efficiency losses, particularly at high hydraulic loads, leading to reduced energy efficiency and potential cavitation.
Innovation Solution
A pump unit design featuring a lip at the inlet that projects into the pump chamber, reducing leakage flow and forming a defined separation edge, combined with a non-circular outlet inlet surface to minimize axial and radial disturbances, enhancing magnetic bearing and drive efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic bearing is used to levitate the rotor without contact, then mechanical wear is eliminated and reliability is improved, but leakage flow increases and energy efficiency decreases
Solution Approach 1:
A magnetic coupling device is introduced as an intermediary between the rotor and stator to transmit rotational force without direct mechanical contact. This mediator allows the rotor to remain levitated (maintaining reliability) while still efficiently transmitting power (reducing energy loss) through magnetic field interaction rather than direct contact.
Solution Approach 2:
The patent replaces traditional mechanical bearing contact with a magnetic field-based coupling system. The mechanical transmission path is substituted with electromagnetic interaction, where magnetic fields transmit torque without physical contact, thereby eliminating wear while maintaining efficient power transfer.
2Device complexity
If the rotor is fully magnetically supported without separate magnetic bearings, then device complexity is reduced, but control precision over radial position decreases
Solution Approach 1:
The stator is designed to serve multiple functions simultaneously: it acts as both the drive stator (generating rotational torque) and the bearing stator (providing magnetic support and radial position control). This multi-functional design reduces overall system complexity while maintaining precise control capabilities through integrated electromagnetic control.
Solution Approach 2:
The patent employs active control of electromagnetic field parameters (current magnitude, frequency, and phase) to dynamically adjust the magnetic forces supporting the rotor. By changing these parameters in real-time, the system maintains precise radial position control despite the simplified single-stator design.
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
Significantly reduces leakage flow and associated forces, improving efficiency and energy efficiency by minimizing cavitation and stabilizing the rotor, while maintaining high hydraulic performance.
Implementation Method 1
The electrical windings of the stator generate a rotating magnetic field that exerts a torque on the rotor, causing it to rotate around a target axis defined by the axial direction
Implementation Method 2
This field also exerts an adjustable lateral force on the rotor, allowing its radial position to be actively controlled
Implementation Method 3
the rotor is passively magnetically supported and stabilized by reluctance forces, meaning it cannot be controlled directly
Implementation Method 4
the rotor is magnetically mounted without contact by means of the stator and can be driven to rotate in an axial direction without contact
Data Source
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AI summary
A pump unit for a centrifugal pump is proposed, comprising the pump unit and a stator (100) extending in an axial direction (A) from a first axial end (110) to a second axial end (120), wherein a cup-shaped recess is provided at the first axial end (110) into which the pump unit (1) can be inserted, wherein the pump unit (1) has a pump housing (2) with an inlet (21) and with an outlet (22) for a fluid to be pumped, and a rotor (10) arranged in the pump housing (2) with a plurality of vanes (103) for pumping the fluid, wherein each vane (103) extends in an axial direction to an end face (107) of the rotor (10) facing the inlet, wherein the pump housing (2) defines a pump chamber (23), and wherein the rotor (10) is rotatable about the axial direction (A).The pump unit (1) is designed for contactless magnetic mounting of the rotor (10) and for contactless magnetic drive of the rotor (10) by the stator (100), the pump housing (2) comprising a cover part (4) and a base part (3), the base part (3) having a cylindrical cup (31) for receiving the rotor (10), which cup (31) can be inserted into the cup-shaped recess of the stator (100). The inlet (21) has a lip (28) which forms an axial end of the inlet (21), the lip (28) projecting into the pump chamber (23) and ending, viewed in the direction of flow, from the end face (107) of the rotor (10) when the rotor (10) is centered with respect to the axial direction (A) in the operating state. Furthermore, a centrifugal pump for conveying a fluid is proposed, comprising such a pump unit (1).