Asymmetric Discharging Valves in Rotary Compressors

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Solution Overview

Problem

Rotary compressors experience noise amplification due to resonance of discharging pressure pulsations and increased pressure loss when discharging valves for both ports are opened simultaneously, and there is a need to improve compression performance at low rotation speeds.

Innovation Solution

A rotary compressor design with asymmetrically sized discharging ports and valves, where one discharging port and valve have a smaller opening area than the other, allowing the smaller valve to open at a lower differential pressure, thereby reducing discharging resistance and pulsation, and enhancing compression performance at low rotation speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If discharging valves are opened simultaneously at the same timing, then the structure is simple and operation is easy, but noise is amplified due to resonance of discharging pressure pulsations

Engineering Contradiction:

Improvevalve opening timing controlVSAvoidnoise amplification

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by making the opening areas of the two discharging ports different from each other. Specifically, one discharging port has a larger opening area while the other has a smaller opening area. This asymmetric design causes the discharging valves to open at different timings due to the differential pressure requirements, thereby preventing synchronous opening and the resulting resonance noise amplification.

Inventive Principle:

Principle #4Asymmetry

2Object-affected harmful factors

If discharging valves are opened at different timings to prevent resonance, then noise is reduced, but the timing coordination becomes complex

Engineering Contradiction:

Improvenoise reductionVSAvoidvalve timing coordination

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent applies local quality by giving different opening areas to different discharging ports. The first discharging port has a larger opening area optimized for its specific location and flow requirements, while the second discharging port has a smaller opening area. This local differentiation in opening areas naturally creates different opening timings for the valves, achieving noise reduction through asymmetric design rather than complex coordinated control.

Inventive Principle:

Principle #3Local quality

3Productivity

If a discharging valve opens at low rotation speed, then compression performance improves, but pressure loss increases due to over-compression

Engineering Contradiction:

Improvecompression performanceVSAvoidpressure loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the discharging valve opening characteristics adaptable to different operating conditions. The asymmetric opening areas allow the valve with the smaller opening area to open at lower differential pressures, which occurs at lower rotation speeds. This dynamic response enables the valve to open appropriately at low rotation speeds to maintain compression performance while avoiding the pressure loss associated with delayed opening.

Inventive Principle:

Principle #15Dynamics

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 design reduces noise and pressure loss, improves compression performance, and prevents resonance of discharging pressure pulsations by optimizing the opening timing and size of the discharging valves, especially at low rotation speeds.

Implementation Method 1

one discharging valve, which opens and closes the one discharging port having the small opening area is opened by smaller differential pressure compared to the other discharging valve among the discharging valves

Methodology Applied

Scientific EffectDifferential pressure: Pressure Gradient

Data Source

PatentEP3184822B1Rotary compressor and refrigeration cycle device

Publication Date: 2021.03.31 TOSHIBA CARRIER CORP

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AI summary

Provided are: a rotary compressor wherein it is possible to reduce discharge resistance and pulsation, improve performance, and reduce noise; and a refrigeration cycle device. A compression mechanism part (12) has a cylinder (15) and a pair of closing members (17, 18) for closing off both ends of the cylinder (15) and forming a cylinder chamber (16) in the cylinder (15). The closing members (17, 18) are provided with discharge ports (22, 26) for discharging a hydraulic fluid compressed in the cylinder chamber (16) and discharge valves (23, 27) for opening/closing the discharge ports (22, 26). One of the discharge ports (22), which is formed in one of the closing members (17), is formed so as to have a smaller opening area than that of the other discharge port (26), which is formed in the other closing member (18). One of the discharge valves (23), for opening/closing the discharge port (22) having the smaller opening area, is opened by a smaller differential pressure than that for the other discharge valve (27).