Compressor and freezer

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Solution Overview

Problem

Rotary compressors experience a closing delay phenomenon in the discharge valve, leading to increased noise, vibration, and impact load due to an improper ratio of hydraulic diameters in the outlet flow path and inflow end of the discharge port, causing the valve body to close prematurely.

Innovation Solution

The compressor design includes a fixed member with a discharge port and a discharge valve having a specific hydraulic diameter ratio of 0.602 to 0.740, a valve head diameter ratio of 3.5 to 5.2, and a maximum number of revolutions of 118 rps, which facilitates quick discharge of fluid and reduces the closing delay phenomenon.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the hydraulic diameter ratio of the outlet flow path to the inflow end of the discharge port is improper, then the valve body lifts up fully at an increased rotational angle, but the closing delay phenomenon occurs and the valve body closes rapidly before the closing period ends

Engineering Contradiction:
Improvevalve body lifting speedVSAvoidclosing period duration
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent applies parameter changes by optimizing the hydraulic diameter ratio (Do/Di) to a specific range of 0.602 or more and 0.740 or less. This parameter adjustment controls the fluid flow characteristics through the discharge port, ensuring that the valve body closes at the appropriate timing without excessive delay or rapid closure, thereby resolving the contradiction between valve lifting speed and closing period duration.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If the seating speed of the valve body on the outflow end of the discharge port increases, then the closing delay phenomenon is reduced, but the exciting force generated when the valve body abuts on the outflow end increases

Engineering Contradiction:
Improveclosing delayVSAvoidexciting force
Core Design Contradiction:
Loss of timeVSForce

Solution Approach 1:

The patent uses parameter changes by controlling the hydraulic diameter ratio (Do/Di) within the range of 0.602 or more and 0.740 or less. This parameter optimization balances the seating speed of the valve body to prevent both closing delay and excessive exciting force, achieving a harmonious operation where the valve closes at the right time without generating excessive impact forces.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the valve body closes rapidly at timing before the closing period ends, then the closing delay phenomenon occurs, but the noise and vibration generated in the operation of the discharge valve increase

Engineering Contradiction:
Improvedischarge valve operation speedVSAvoidnoise and vibration
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by optimizing the hydraulic diameter ratio (Do/Di) to fall within the range of 0.602 or more and 0.740 or less. This parameter control regulates the fluid flow and pressure distribution during valve closure, ensuring that the valve body closes smoothly at the appropriate timing, thereby preventing both closing delay and the generation of excessive noise and vibration.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the impact load acting on the valve body increases, then the valve body closes more effectively, but the durability and reliability of the discharge valve decrease

Engineering Contradiction:
Improvevalve closure effectivenessVSAvoidvalve body durability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses parameter changes by maintaining the hydraulic diameter ratio (Do/Di) within the optimized range of 0.602 or more and 0.740 or less. This parameter control ensures that the valve body closes effectively with appropriate seating speed, preventing both closing delay and excessive impact loads that would compromise the durability and reliability of the discharge valve.

Inventive Principle:
Principle #35Parameter changes

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 configuration minimizes resistance and delays in the discharge process, enhancing the efficiency and reducing noise and vibration, thereby improving the performance of the compressor and refrigeration apparatus.

Implementation Method 1

While the internal pressure of a compression chamber is lower than the back pressure of the valve body, the valve body closes the discharge port to reduce the backflow of a fluid into the compression chamber. On the other hand, when the internal pressure of the compression chamber becomes higher than the back pressure of the valve body, the valve body is elastically deformed and apart from the outflow end of the discharge port.

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

when the internal pressure of the compression chamber becomes higher than the back pressure of the valve body, the valve body is elastically deformed and apart from the outflow end of the discharge port

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4386209B1Compressor and freezer
Publication Date: 2025.09.24 DAIKIN INDUSTRIES LTD
  • EP4386209B1 patent drawingFigure 1
  • EP4386209B1 patent drawingFigure 2
  • EP4386209B1 patent drawingFigure 3

AI summary

An inflow end (51) of a discharge port (50) has a hydraulic diameter Di expressed by Di = 4 × (Ai/Li), where Ai is an area of the inflow end (51) and Li is a circumferential length at the inflow end (51). An outlet flow path (70) is formed between an outflow end (52) of the discharge port (50) and a valve body (61). The outlet flow path (70) has a cross-sectional area Ao expressed by Ao = Lo × ho and a hydraulic diameter Do expressed by Do = 4 × {Ao/(Lo + Lv)}, where Lo is a circumferential length at the outflow end (52) of the discharge port (50), ho is a reference lift amount of the valve body (61), and Lv is a circumferential length of a valve head (64) of the valve body (61). The hydraulic diameter ratio (Do/Di) in this case is 0.602 or more and 0.740 or less.