Multicylinder Rotary Compressor Vane Back-Pressure Control

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Solution Overview

Problem

In multicylinder rotary compressors, the switching between operation modes leads to increased pressure pulsation and collision sounds due to the absence of spring members in the second vane, affecting the follow-up property and efficiency of the compression process.

Innovation Solution

A compression system with a multicylinder rotary compressor that includes a valve device to control refrigerant flow, applying intermediate pressures between suction-side and discharge-side pressures as back pressure for the second vane during mode switching, and using a back-pressure chamber with a predetermined volume to reduce pressure pulsation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spring members are eliminated from the second vane to enable one-cylinder operation, then capacity adaptability is improved, but pressure stability deteriorates causing collision sounds

Engineering Contradiction:

Improveoperation mode switching capabilityVSAvoidpressure stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

A back-pressure chamber is introduced as an intermediary component between the second vane and the high-pressure chamber. This chamber receives discharge-side pressure from the high-pressure chamber and applies it as back pressure to the second vane, mediating the pressure interaction to maintain stability during operation mode switching without requiring spring members

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes pressure parameters by switching between different operation modes (one-cylinder and two-cylinder modes). By controlling which cylinders are active and adjusting the corresponding back pressure applied to vanes, the system adapts capacity while maintaining pressure stability through the back-pressure chamber mechanism

Inventive Principle:

Principle #35Parameter changes

2Power

If discharge-side pressure is applied as back pressure to the second vane, then compression work is enabled in two-cylinder mode, but pressure pulsation increases causing collision sounds

Engineering Contradiction:

Improvecompression work capabilityVSAvoidpressure pulsation

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The back-pressure chamber acts as a cushioning volume that absorbs and dampens pressure pulsations before they reach the second vane. By providing a predetermined volume for pressure equalization, the system cushions the harmful effects of pressure fluctuations and prevents collision sounds while maintaining compression work capability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If intermediate pressure is applied as back pressure during mode switching, then follow-up property is improved, but collision sounds occur during switching transition

Engineering Contradiction:

Improvevane follow-up propertyVSAvoidcollision sound during switching

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The back-pressure chamber is pre-configured with a predetermined volume to establish stable back pressure conditions before mode switching occurs. This preliminary preparation of the pressure environment enables smooth vane follow-up during transitions without causing collision sounds

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

Improves the follow-up property of the second vane, reduces collision sounds, and enhances the overall efficiency and reliability of the compression system by minimizing pressure fluctuations and ensuring smooth operation during mode switching.

Implementation Method 1

using a back-pressure chamber with a predetermined volume to reduce pressure pulsation

Methodology Applied

Scientific EffectPressure pulsation reduction: Damping

Implementation Method 2

applying intermediate pressures between suction-side and discharge-side pressures as back pressure for the second vane during mode switching

Methodology Applied

Scientific EffectPressure application: Pressure Gradient

Data Source

PatentUS7524174B2Compression system, multicylinder rotary compressor, and refrigeration apparatus using the same

Publication Date: 2009.04.28 SANYO ELECTRIC CO LTD

AI summary

An object is to avoid generation of a collision sound of a second vane of a compression system comprising a multicylinder rotary compressor being configured to be used by switching of a first operation mode in which both rotary compression elements perform a compression work and a the second operation mode in which the only first rotary compression element substantially performs the compression work. When the second operation mode is switched to the first operation mode, discharge-side pressures of both the rotary compression elements are applied as a back pressure of the second vane, and thereafter an intermediate pressure is applied which is between suction-side and discharge-side pressures of both the rotary compression elements. When the first operation mode is switched to the second operation mode, a valve device interrupts flowing of a refrigerant into a second cylinder, and thereafter suction-side pressures of both the rotary compression elements are applied as the back pressure of the second vane.