Dual Motor Centrifugal Compressor Flexible Coupling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Integrated motor-compressor units with rigid couplings face limitations in delivering high power at high rotational speeds due to alignment issues and increased stress on shafts, and are restricted by stringent environmental regulations in explosive atmospheres.

Innovation Solution

A motor-compressor unit with dual high-speed electric motors connected to a centrifugal compressor via flexible couplings, allowing for higher power output at the same speed and reduced stress, along with an integrated cooling system to prevent gas leaks and simplify assembly and maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid coupling is used to connect the rotor and driven shaft, then alignment is simplified and structural integrity is improved, but perfect alignment during assembly is required which increases manufacturing complexity

Engineering Contradiction:
Improvestructural integrityVSAvoidalignment precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A flexible coupling element is introduced between the rotor and driven shaft to replace the rigid coupling. This flexible element allows for misalignment compensation while maintaining the mechanical connection, thereby eliminating the need for perfect alignment during assembly while preserving structural integrity and power transmission.

Inventive Principle:
Principle #30Flexible shells and thin films

2Power

If the size of the compressor fins is increased to achieve higher power, then power output is improved, but stresses on the shaft line increase prohibitively

Engineering Contradiction:
Improvepower outputVSAvoidshaft line stress
Core Design Contradiction:
PowerVSStress or pressure

Solution Approach 1:

The power transmission is segmented by using two separate high-speed electric motors instead of one large motor. Each motor drives the compressor through its own flexible coupling, distributing the mechanical stresses across multiple components and allowing higher total power output without prohibitively increasing stress on any single shaft line.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If a flexible coupling is used to connect the rotor and driven shaft, then alignment problems are overcome and vibration behaviors are preserved, but power transmission capability is limited

Engineering Contradiction:
Improveassembly easeVSAvoidpower transmission
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The flexible coupling is designed to dynamically adapt to misalignment conditions while maintaining effective power transmission. The flexible element can deform to accommodate alignment variations and retain the vibration characteristics of the rotor, yet still transmit sufficient power for high-speed operation.

Inventive Principle:
Principle #15Dynamics

4Power

If motor-compressor units operate in explosive atmospheres, then power delivery is improved, but strict environmental regulations restrict the design

Engineering Contradiction:
Improvepower deliveryVSAvoidexplosive atmosphere risk
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The design replaces traditional mechanical drive systems with high-speed electric motors that can be intrinsically safer for explosive atmosphere applications. The electric motors operate at speeds higher than the electrical power supply frequency, enabling power delivery while meeting environmental standards through reduced mechanical ignition sources.

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

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 solution enables higher power transmission at higher rotational speeds without oversizing the compressor, maintains dynamic rotor characteristics, and adheres to strict environmental standards by minimizing gas leaks and stress on components.

Implementation Method 1

the rotor and the driven shaft being linked by a flexible coupling arranged in the casing

Methodology Applied
Scientific EffectFlexible coupling: Elasticity

Implementation Method 2

centrifugal compressor unit comprising a first motor, at least one compressor comprising a driven shaft driven by the rotor of the first motor and a set of impellers mounted on the driven shaft

Methodology Applied
Scientific EffectCentrifugal compression: Centrifugal Force

Implementation Method 3

the compressor unit includes engine cooling means. Thanks to this integrated cooling system, an internal circulation of gases is created

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP2444675B1Centrifugal compressor unit
Publication Date: 2019.08.14 THERMODYN
  • EP2444675B1 patent drawingFigure 1
  • EP2444675B1 patent drawingFigure 2~3

AI summary

The unit (1) has a multi-stage compressor (2) comprising a drive shaft (9) driven by a rotor (12) of an electric motor (3), and a set of impellers (5-8) mounted on the drive shaft. The set of impellers formed by the motor and the compressor is mounted in a gas-tight common housing (26) operated by the compressor unit. The rotor of the motor and the drive shaft are connected by a flexible coupling (24) placed in the housing. Another electric motor (4) is placed in the housing and includes a rotor (13) connected to the drive shaft by another flexible coupling (25).