Compressor Inlet Valve Discrete Step Control for Vibration Reduction

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Solution Overview

Problem

Conventional compressors experience high vibration levels and potential damage during the transition from a loaded to an unloaded state due to sudden changes in pressure ratios, which can lead to undesirable temperature peaks and mechanical stress, especially when there is no elastic coupling between the drive and compressor elements.

Innovation Solution

A method for controlling the compressor that involves partially closing the inlet valve in successive discrete steps during the transition from the loaded to the unloaded state, allowing a greater suction flow to maintain a higher equilibrium pressure, thereby reducing the pressure ratio peak and minimizing vibrations. This is achieved by determining the operating pressure in the consumer network and initiating the transition when it reaches a set maximum, and then gradually reducing the flow to the residual flow required for the unloaded state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the inlet valve is immediately closed and blow-off valve is opened during transition from loaded to unloaded state, then the transition to unloaded state is achieved quickly, but high pressure ratio peaks occur causing dangerous vibration levels and potential compressor failure

Engineering Contradiction:
Improvetransition speed to unloaded stateVSAvoidcompressor reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The transition process is segmented into multiple discrete steps rather than a single sudden change. The inlet valve is closed in successive discrete transitional steps, allowing the pressure ratio to decrease gradually through intermediate states rather than jumping directly to the final unloaded state, thereby avoiding dangerous vibration peaks

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inlet valve is partially closed in preliminary steps before complete closure is achieved. This preliminary action reduces the pressure ratio incrementally in advance of the final transition completion, preventing the sudden pressure ratio peak that would occur with immediate full closure

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If the inlet valve is closed completely in the unloaded state, then no gas is suctioned and energy consumption is minimized, but the calibrated passages cannot maintain sufficient pressure for fluid injection cooling and lubrication

Engineering Contradiction:
Improveenergy consumption in unloaded stateVSAvoidcompressor element cooling and lubrication
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The inlet valve closure is not absolute but localized with calibrated passages remaining open. This creates different flow conditions in different parts of the inlet system - the main inlet is closed to minimize energy consumption while specific calibrated passages remain open to maintain minimum pressure for fluid injection, achieving both energy efficiency and component protection

Inventive Principle:
Principle #3Local quality

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 method effectively reduces the peak pressure ratio between the outlet and inlet, preventing hazardous vibration levels and allowing for safe operation without an elastic coupling, while also optimizing energy use by maintaining a higher equilibrium pressure in the pressure tank.

Implementation Method 1

a compressor element (2) with an inlet (5) and an outlet (10)

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a controllable inlet valve (6) with a valve inlet (7), in which the inlet valve (6) can at least partially close the inlet (5) of the compressor element (2)

Methodology Applied
Scientific EffectValve control: Valve

Implementation Method 3

a controllable blow-off valve (19) which is connected to the pressure line (11)

Methodology Applied
Scientific EffectPressure release: Valve

Data Source

PatentEP3918201B1A method for controlling a compressor towards and unloaded state
Publication Date: 2024.09.11 ATLAS COPCO AIRPOWER NV
  • EP3918201B1 patent drawingFigure 1
  • EP3918201B1 patent drawingFigure 2
  • EP3918201B1 patent drawingFigure 3

AI summary

A method for controlling a compressor towards an unloaded state, in which the compressor comprises a compressor element 2) with an inlet (5), in which in the unloaded state, a residual flow (QD) is suctioned via the inlet (5) towards and into the compressor element (2), and in which for a transition from a loaded state of the compressor to the unloaded state, the inlet (5) of the compressor element (2) is partially closed in successive discrete transitional steps,