Smart Blow-Down Control for VFD Compressor Units

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Solution Overview

Problem

Conventional variable frequency drive (VFD) compressor units experience energy loss, lubricant loss, and environmental issues due to frequent blow-downs, which are unnecessary and lead to moisture condensation causing rust and reducing the service life of compressor components.

Innovation Solution

A smart blow-down system that uses temperature and pressure sensors to determine when to maintain pressure in the sump, preventing unnecessary blow-downs by only depressurizing when the temperature drops below a predetermined threshold, thereby minimizing energy loss and condensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the compressor unit is blown-down frequently to prevent pressure buildup, then pressure control is maintained, but energy loss and lubricant loss increase

Engineering Contradiction:

Improvepressure controlVSAvoidenergy loss

Core Design Contradiction:

Stress or pressureVSLoss of energy

Solution Approach 1:

The system changes the parameter of blow-down frequency from frequent/conventional to infrequent/optimized based on actual compressor operation patterns. The controller monitors compressor runtime and only initiates blow-down when the compressor has been running for a predetermined period, reducing unnecessary blow-downs and associated energy losses.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements feedback control by monitoring compressor operation parameters (runtime, pressure) and using this information to determine when blow-down is actually necessary. The controller continuously assesses whether the compressor meets the criteria for blow-down based on real-time operational data, avoiding premature or unnecessary blow-down events.

Inventive Principle:

Principle #23Feedback

2Stress or pressure

If the compressor unit is blown-down frequently to maintain pressure, then pressure is controlled, but lubricant loss increases

Engineering Contradiction:

Improvepressure controlVSAvoidlubricant loss

Core Design Contradiction:

Stress or pressureVSLoss of substance

Solution Approach 1:

The system optimizes the timing parameter of blow-down operations to occur only when the compressor has been running for a predetermined period. This parameter change reduces the frequency of blow-downs, thereby minimizing lubricant loss while still maintaining adequate pressure control when needed.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system maintains continuous pressure control by ensuring the compressor runs long enough to build adequate pressure before a blow-down is initiated. This continuity approach ensures that pressure is maintained during operation and only released when necessary, preventing unnecessary lubricant evaporation and loss.

Inventive Principle:

Principle #20Continuity of useful action

3Loss of energy

If the compressor unit is blown-down to save energy, then energy consumption is reduced, but moisture condensation occurs causing rust

Engineering Contradiction:

Improveenergy consumptionVSAvoidmoisture condensation

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The system uses feedback from temperature and pressure sensors to determine the appropriate timing for blow-down operations. By monitoring actual operating conditions, the controller ensures blow-down occurs only when safe and necessary, preventing moisture condensation that would occur with premature or frequent blow-downs.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary assessment of compressor runtime and operating conditions before initiating blow-down. This preliminary action ensures that the compressor has been running long enough to prevent moisture condensation during the blow-down process, while still achieving energy savings through reduced blow-down frequency.

Inventive Principle:

Principle #10Preliminary 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

The system reduces energy consumption, minimizes lubricant loss, and extends the life of compressor components by optimizing blow-down operations, making it more environmentally friendly and reliable.

Implementation Method 1

A smart blow-down system that uses temperature and pressure sensors to determine when to maintain pressure in the sump

Methodology Applied

Scientific EffectTemperature sensing:

Implementation Method 2

A smart blow-down system that uses temperature and pressure sensors to determine when to maintain pressure in the sump

Methodology Applied

Scientific EffectPressure sensing:

Implementation Method 3

When the VFD compressor unit is blown-down, the compressed air inside the VFD compressor unit can cause moisture condensation

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentUS8721301B2Smart blow-down system for variable frequency drive compressor units

Publication Date: 2014.05.13 QUINCY COMPRESSOR LLC

AI summary

A method and apparatus for blowing down a compressed air system when temperature is at or below a predefined temperature threshold is provided. Temperature sensors in the compressed air system monitor temperature and a control processor determines when the temperature is at or below the predefined temperature threshold. When it is determined temperature is at or below the predefined temperature threshold, the control processor operates a solenoid blow-down valve that depressurizes the compressed air system.