Rotary Compressor Segmentation for Off-Load Efficiency

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Solution Overview

Problem

Standard rotary air compressors waste significant energy during off-load operation due to re-compression, and oil-lubricated compressors face mechanical stress from pressurization and depressurization cycles, which can affect the durability of the cooling radiator.

Innovation Solution

Incorporating a second, low-pressure chamber and using a three-way valve to divert the air flow during off-load mode, allowing the compressor to immediately reduce power absorption to less than 25% of on-load levels, while maintaining the air-oil separation tank and oil injection circuit at a stable pressure, thus avoiding mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the compressor uses a system of gradual depressurisation of the tank to decrease power absorption during off load operation, then power absorption is reduced to 25% of on load operation, but the compressor causes a transient in which considerable energy is still wasted and the cooling radiator undergoes considerable mechanical stress

Engineering Contradiction:

Improvepower absorption during off load operationVSAvoidenergy waste during transient period

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The invention divides the single compression chamber into two separate chambers: a first compression chamber that maintains high pressure for normal operation, and a second compression chamber that maintains low pressure for off-load operation. This segmentation allows the compressor to avoid the transient energy waste by immediately switching to the low-pressure chamber when off-load conditions occur, rather than gradually depressurizing the entire tank.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If the compressor uses a system of gradual depressurisation of the tank to decrease power absorption during off load operation, then power absorption is reduced to 25% of on load operation, but the cooling radiator undergoes considerable mechanical stress which could jeopardise its intactness

Engineering Contradiction:

Improvepower absorption during off load operationVSAvoidintactness of cooling radiator

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies different pressure conditions to different parts of the system: the first compression chamber and its associated components operate at high pressure, while the second compression chamber operates at low pressure. This local differentiation allows the cooling radiator to remain at stable high pressure during normal operation and avoid the mechanical stress of repeated pressurization and depressurization cycles.

Inventive Principle:

Principle #3Local quality

3Use of energy by moving object

If the compressor changes from 100% absorption to approximately 25% absorption gradually, then power absorption is reduced during off load operation, but the transition causes a transient in which considerable energy is still wasted

Engineering Contradiction:

Improvepower absorption during off load operationVSAvoidtransient period duration

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The invention prepares the second low-pressure chamber in advance, keeping it ready to immediately receive compressed air when off-load conditions occur. This preliminary preparation eliminates the transient period entirely, as the system can instantly switch from high-pressure to low-pressure operation without any gradual transition, thereby avoiding energy waste during the switch-over period.

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

This solution significantly reduces energy waste and extends the lifespan of compressor components by minimizing power consumption during off-load operation and maintaining a stable pressure, reducing mechanical stress on the oil injection circuit.

Implementation Method 1

using a three-way valve to divert the air flow during off-load mode

Methodology Applied

Scientific EffectFluid flow diversion:

Implementation Method 2

the rotor of the compressor in any case continues to rotate and therefore performs compression work

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 3

maintaining the air-oil separation tank and the oil injection circuit at the rated working pressure

Methodology Applied

Scientific EffectPressure differential separation:

Data Source

PatentEP1798416B1Rotary compressor with improved working efficiency and relative method

Publication Date: 2009.04.22 ING ENEA MATTEI

Figure 1~2
Figure 3~4

AI summary

A rotary compressor (1) comprising at least one compression chamber provided with an intake air flow inlet (2) and a delivery air flow or air-oil mixture outlet (3), means for closure of the intake and a first, high-pressure chamber (4) of the compressor, also comprising a second, low-pressure chamber (6) of the compressor, and means (8) for selective deviation of said delivery air-oil mixture or air flow of the compressor to said first, high-pressure chamber (4) or to said second, low-pressure chamber (6) of the compressor, and a relative method for increasing the working efficiency of the rotary compressor (1).