Expansion Valve Layout for Compact Size and Lower Refrigerant Noise

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Solution Overview

Problem

The reduction in size of air conditioning devices has made it challenging to maintain installation space for expansion valves, and the use of expensive materials, while larger bubble diameters in refrigerant cause noise issues due to bubble entrainment and breakage within the valve chamber.

Innovation Solution

The expansion valve design features a plug mounted to an upper position, reducing vertical size, and incorporates a coil spring with closely spaced coil wires to minimize bubble size and noise by breaking bubbles into finer sizes, without increasing component count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If the expansion valve is reduced in size to save installation space and reduce material cost, then the valve body becomes more compact and cost-effective, but it becomes more challenging to maintain adequate installation space and may affect performance

Engineering Contradiction:
Improvevalve body sizeVSAvoidinstallation space availability
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

The patent repositions the plug from the bottom surface to the upper surface of the valve body, utilizing the vertical dimension differently. This dimensional reconfiguration allows the valve body to be reduced in overall size while maintaining functional requirements and installation space availability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The plug position is inverted from the conventional bottom-mounted configuration to an upper-mounted configuration. This inversion resolves the contradiction by enabling compact valve body design while preserving installation flexibility and performance.

Inventive Principle:
Principle #13The other way round (Inversion)

2Quantity of substance

If the liquid refrigerant passes through the valve chamber with larger bubble diameters, then the refrigerant flow is maintained, but noise occurs when the bubbles break within the valve chamber

Engineering Contradiction:
Improverefrigerant flowVSAvoidrefrigerant passing noise
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical parameter of bubble diameter by introducing a mechanism that breaks large bubbles into smaller bubbles before they enter the valve chamber. This parameter change reduces the noise generated during bubble breakage while maintaining refrigerant flow quantity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The bubble breaking action is performed preliminarily before the refrigerant enters the valve chamber. By pre-breaking the bubbles in the refrigerant passage, the harmful noise-generating large bubbles are eliminated before they can cause noise in the valve chamber, while the refrigerant flow is preserved.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If expensive materials are used for the valve body, then the manufacturing quality and durability are improved, but the material cost increases

Engineering Contradiction:
Improvevalve body durabilityVSAvoidmaterial cost
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the design parameters of the valve body, including wall thickness and structural configuration, to achieve adequate durability with reduced material usage. This allows the use of less expensive materials or reduced material quantities while maintaining reliability standards.

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 reduces the vertical and lateral size of the valve body, decreases material usage and cost, and significantly lowers refrigerant passing noise by minimizing bubble size and noise production upon breakage.

Implementation Method 1

bubbles in the liquid refrigerant are reduced to a finer size by the coil wires of the coil spring when the liquid refrigerant passes through the coil spring

Methodology Applied
Scientific EffectMechanical disruption:

Implementation Method 2

heat of the gas phase refrigerant flowing through the second passage 34 is transferred via the valve member driving rod 36f located in the second passage 34 and the pressure equalizing hole 36e and the diaphragm 36a

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

The diaphragm driving fluid in the upper pressure operating chamber 36b is gasified by the transferred heat, and a pressure of the gas is applied to an upper surface of the diaphragm 36a

Methodology Applied
Scientific EffectGasification: Phase Change

Data Source

PatentEP1950510B1Expansion valve
Publication Date: 2013.04.17 FUJIKOKI CORP
  • EP1950510B1 patent drawingFigure 1A~1B
  • EP1950510B1 patent drawingFigure 2
  • EP1950510B1 patent drawingFigure 3

AI summary

In an expansion valve, in a first passage 12 through which a high pressure liquid refrigerant flows, an inlet port 321 includes a large diameter passage portion 13 formed from one side surface to the other side surface of a valve body 30, and a small diameter passage portion 14 that provides communication between the large diameter passage portion 13 on the bottom end thereof and a valve chamber 15. A coil spring 20 provided in the valve chamber 15 biases a valve member 32b toward a valve hole 32a. An O ring 19 that seals between a plug 17 that supports a lower end of the coil spring 20 and the valve body 30 is located below the small diameter passage portion 14 and placed on the opposite side of the bottom end of the large diameter passage 13. Thus, the plug 17 that closes an opening of the valve chamber 15 can be mounted to an upper position, thereby reducing a vertical size of the valve body 30 to further reduce a size of the valve body, and reducing an amount of use of metal materials for the valve body to reduce weight and cost.