Scroll Compressor Bypass Port Reduces Fluid Pulsation

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Solution Overview

Problem

Conventional scroll compressors experience fluid pulsation due to direct flow of compressed fluid into the fluid feed line, which affects the efficiency and performance of the compressor.

Innovation Solution

A scroll compressor design that includes a bypass port, first and second check valves, and an on/off valve to manage fluid flow, guiding the mid-compression fluid through a bypass pipe and discharge pipe, reducing pulsation by controlling fluid pressure and flow paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the bypass port and discharge port are connected directly to the fluid feed line, then the compressor can operate with simplified structure, but fluid pulsation occurs affecting efficiency

Engineering Contradiction:
Improvestructure simplificationVSAvoidfluid pulsation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediate chamber as a mediator between the bypass/discharge ports and the fluid feed line. This intermediate chamber receives compressed fluid from both ports and gradually supplies it to the feed line, preventing direct connection that causes pulsation while maintaining structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If check valves are used to control fluid flow direction, then fluid flow can be precisely controlled, but device complexity increases

Engineering Contradiction:
Improvefluid flow controlVSAvoidvalve mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The check valves in the patent are designed to automatically control fluid flow direction based on pressure differences without external control mechanisms. The valves open or close autonomously according to flow conditions, achieving precise fluid control while minimizing additional complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If mid-compression fluid is removed through bypass port, then excessive compression is prevented, but pressure loss increases

Engineering Contradiction:
Improvecompression controlVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes mid-compression fluid through the bypass port to prevent excessive compression, but then recovers this fluid by introducing it into the intermediate chamber where it can be mixed with discharge fluid and supplied to the feed line. This approach prevents energy waste while maintaining compression control.

Inventive Principle:
Principle #34Discarding and recovering

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 design effectively reduces fluid pulsation, enhances the degree of freedom in positioning the bypass and discharge ports, and minimizes pressure loss, thereby improving the operational efficiency and stability of the compressor.

Implementation Method 1

When a pressure difference between a discharge chamber, which is disposed inside an intermediate chamber in which the first check valve and the second check valve are disposed, and the intermediate chamber is small, the fluid can be drawn to a discharge space before the fluid is excessively compressed.

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a second check valve configured to become open when the capacity control operation is turned off and when a pressure in the intermediate chamber becomes higher than a pressure in the discharge chamber, and to discharge the mid-compression fluid, which is discharged to the intermediate chamber, to the discharge chamber via the discharge port

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

an on/off valve configured to become open when capacity control operation of the fluid is turned on, and to return the mid-compression fluid, which is discharged to the intermediate chamber, to the suction chamber

Methodology Applied
Scientific EffectValve control: Valve

Data Source

PatentEP3339646B1Scroll compressor with bypass port
Publication Date: 2024.03.13 MITSUBISHI HEAVY IND THERMAL SYST
  • EP3339646B1 patent drawingFigure 1
  • EP3339646B1 patent drawingFigure 2~3
  • EP3339646B1 patent drawingFigure 4

AI summary

Provided is a scroll compressor capable of inhibiting occurrence of pulsation of a fluid. The scroll compressor includes: an on/off valve (38) that opens when the capacity control operation of a fluid is turned on, and returns a mid-compression fluid, which is discharged to an intermediate chamber (81), to a suction chamber (17); and a second check valve (42) that opens when the capacity control operation is turned off and when a pressure in the intermediate chamber (81) becomes higher than a pressure in a discharge chamber (16), and discharges the mid-compression fluid, which is discharged to the intermediate chamber (81), to the discharge chamber (16) via a discharge port (85).