Helico-Axial Pump Rotor Stabilization via Hydrodynamic Bushing

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Solution Overview

Problem

Helico-axial pumps used for conveying multi-phase mixtures face significant challenges with rotor vibrations, which reduce efficiency and can lead to damage due to intense oscillations, especially as the number of compression stages increases, limiting the pump's operational range and efficiency.

Innovation Solution

The integration of a hydrodynamic stabilization bushing with a stabilization surface between partial rotors forms a stabilization gap, allowing a stabilization layer to form, thereby increasing damping and rigidity of the rotor system, reducing harmful vibrations to a tolerable level and enabling operation at higher speeds or in previously inaccessible rotational fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of compression stages is increased to compress multi-phase mixtures with higher gas content, then the compression capability and density increase, but the rotor length increases and harmful vibrations become more intense

Engineering Contradiction:
Improvecompression capabilityVSAvoidrotor vibrations
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The rotor is divided into multiple partial rotors (first partial rotor, second partial rotor, etc.) that are arranged in series along the longitudinal axis. Each partial rotor contains compression stages, and they are coupled together but can be independently balanced and mounted. This segmentation allows the long rotor structure to be broken into manageable sections, reducing the intensity of vibrations while maintaining the overall compression capability through the series arrangement of multiple partial rotors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coupling device is introduced as an intermediary element between the partial rotors. This coupling device connects the partial rotors while allowing for vibration isolation and dynamic balancing. The coupling acts as a mediator that transmits power and motion between partial rotors while mitigating the transmission of harmful vibrations, enabling the system to handle high gas content mixtures without excessive rotor oscillations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the rotor length is increased to accommodate more compression stages, then the compression ratio improves, but the rotor becomes more difficult to control and efficiency decreases

Engineering Contradiction:
Improvecompression ratioVSAvoidrotor control
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The long rotor is segmented into multiple partial rotors of manageable length. Each partial rotor can be independently controlled, balanced, and maintained, making the overall system easier to operate despite the increased total compression ratio. The segmentation allows for modular assembly and simplifies the control of each section while achieving high compression through series connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling device between partial rotors introduces dynamic flexibility to the system. This allows each partial rotor to respond dynamically to operating conditions independently, improving controllability. The dynamic coupling enables the system to adapt to varying loads and maintain efficient operation across different operating ranges, making the long rotor system more manageable.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the number of compression stages is increased, then the pump can handle higher gas volumes, but the rotor vibrations intensify and may cause damage

Engineering Contradiction:
Improvegas volume handling capabilityVSAvoidrotor stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The rotor system is divided into multiple partial rotors that can be independently balanced and mounted with precise alignment. This segmentation reduces the vibration intensity of each individual section while maintaining the overall capability to handle high gas volumes through the series arrangement. The modular structure improves reliability by isolating vibration sources and enabling targeted maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling device serves as an intermediary that connects partial rotors while providing vibration isolation. This coupling mechanism protects the overall system from harmful vibrations generated by individual partial rotors, thereby maintaining rotor stability and reliability even when handling high gas volumes with multiple compression stages.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If the rotor is made longer with more compression stages, then the pump efficiency for multi-phase mixtures improves, but the operational speed range is limited due to vibration constraints

Engineering Contradiction:
Improvepump efficiencyVSAvoidoperational speed range
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

The segmented rotor structure with multiple partial rotors allows each section to operate within optimal speed ranges while contributing to the overall high efficiency through series compression. The segmentation enables the system to maintain high pump efficiency for multi-phase mixtures without being constrained by the vibration limitations of a single long rotor, thus expanding the operational speed range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dynamic coupling between partial rotors enables each section to respond independently to speed variations, allowing the system to operate efficiently across a broader speed range. This dynamic flexibility maintains pump efficiency for multi-phase mixture handling while avoiding the vibration constraints that would limit the speed range of a conventional long rotor design.

Inventive Principle:
Principle #15Dynamics

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 solution effectively reduces rotor vibrations, allowing for smoother operation, increased efficiency, extended maintenance intervals, and the ability to construct pumps with a higher number of compression stages, leading to reduced energy consumption and extended service life.

Implementation Method 1

a hydrodynamic stabilization bushing (70) with a stabilization surface (700) is provided and designed in the pump housing (6) between the first partial rotor (21) and the second partial rotor (22) in such a way that a stabilization gap (8) is formed in front of the stabilization surface (700), so that a hydrodynamic stabilization layer (S) can be formed from a stabilization medium in the stabilization gap (8)

Methodology Applied
Scientific EffectHydrodynamic stabilization:

Data Source

PatentEP2386767B1Helico-axial pump and method for bearing a rotor in a helico-axial pump
Publication Date: 2021.01.06 SULZER MANAGEMENT AG
  • EP2386767B1 patent drawingFigure 1a~1b
  • EP2386767B1 patent drawingFigure 2
  • EP2386767B1 patent drawingFigure 3

AI summary

The helico-axial pump (1) comprises a partial rotor (21) and a rotor which is arranged in pump housing (6) around a longitudinal axis (A) in a rotating manner. The partial rotor comprises a compression level (K) having a helico-axial propeller (3) and a stator (4) for compression of multiphase mixture (M). A hydrodynamic stabilization bush (70) is arranged with a stabilization surface (700), where a stabilization gap (8) is formed for the stabilization surface. Independent claims are also included for the following: (1) a hybrid pump with a rotor; and (2) a method for hydrodynamic support of a rotor.