Centrifugal compressor for refrigeration system and refrigeration system

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Solution Overview

Problem

In refrigeration systems, unexpected shutdowns cause reverse rotation of the compressor rotor shaft due to pressure differences, leading to turbulent flow, unbalanced forces, and vibrations, which can result in noise and reduced system stability, and existing solutions like check valves create flow resistance and noise.

Innovation Solution

A centrifugal compressor with a reverse braking function, featuring a rotor shaft, compressor impeller, a magnetic conductive brake component, and a set of electromagnets arranged radially, with a sensor device and controller to detect reverse rotation and apply a braking force using magnetic fields to suppress reverse rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a check valve is mounted at the compressor outlet to prevent reverse airflow, then reverse rotation of the rotor shaft is prevented, but flow resistance increases causing pressure drop and efficiency reduction

Engineering Contradiction:

Improveprevention of reverse rotationVSAvoidsystem efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical check valve with an electromagnetic braking system. Electromagnets are positioned to engage with a brake component on the rotor shaft, creating electromagnetic braking force that prevents reverse rotation without creating flow resistance in the refrigerant passage. This substitution eliminates the trade-off between protection and efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a check valve is mounted at the compressor outlet, then reverse rotation is prevented, but significant noise and vibration are generated during opening and closing

Engineering Contradiction:

Improveprevention of reverse rotationVSAvoidnoise and vibration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electromagnetic braking system replaces the mechanical check valve's opening/closing action with continuous electromagnetic force application. The electromagnets can be activated precisely when reverse rotation is detected, creating smooth braking force without the sudden mechanical impacts that cause noise and vibration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The braking force is applied periodically or continuously based on sensor detection of reverse rotation tendency, rather than through intermittent mechanical valve operation. This allows for controlled, smooth engagement of the braking force, eliminating the shock and noise associated with mechanical valve snap-action.

Inventive Principle:

Principle #19Periodic action

3Productivity

If magnetic bearings are used in the compressor, then operational efficiency is improved, but reverse rotation causes excessive vibration and impact against catcher bearing

Engineering Contradiction:

Improveoperational efficiencyVSAvoidsystem stability during reverse rotation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The sensor device detects the tendency for reverse rotation before it fully develops, and the electromagnets are activated in advance to apply braking force. This preliminary anti-action prevents the reverse rotation from occurring in the first place, protecting the magnetic bearings from excessive vibration and impact before these harmful effects can manifest.

Inventive Principle:

Principle #9Preliminary anti-action

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

Effectively prevents reverse rotation of the compressor rotor shaft, reducing vibrations and noise, and maintaining system stability by applying a controlled braking force that counteracts the rotor's gravity and oscillation forces, ensuring the magnetic bearings' capacity is not exceeded.

Implementation Method 1

a plurality of sets of electromagnets fixedly arranged at radial outward of the brake component... the plurality of sets of electromagnets each exert a braking force on the brake component of the rotor shaft when energized

Methodology Applied

Scientific EffectElectromagnetic attraction: Electromagnet

Implementation Method 2

a periphery of the brake component is made of magnetic conductive material... the plurality of sets of electromagnets each exert a braking force on the brake component of the rotor shaft

Methodology Applied

Scientific EffectEddy current damping: Eddy Current Damping

Data Source

PatentUS20240003357A1Centrifugal compressor for refrigeration system and refrigeration system

Publication Date: 2024.01.04 CARRIER CORP

AI summary

The present application provides a centrifugal compressor for a refrigeration system and a refrigeration system. The centrifugal compressor has a reverse braking function and comprises: a rotor shaft; a compressor impeller connected to the rotor shaft; a brake component on the rotor shaft, wherein a periphery of the brake component is made of magnetic conductive material; a plurality of sets of electromagnets fixedly arranged at radial outward of the brake component; a sensor device for sensing a rotational speed and direction of the rotor shaft; and a controller connected to the sensor device, wherein the controller receives signals from the sensor device and supplies power to the plurality of sets of electromagnets based on the signals. The centrifugal compressor and refrigeration system according to the various embodiments effectively suppress the reverse rotation of the compressor rotor shaft caused by the reverse airflow during unexpected shutdown.