Piloted Valve Diaphragm Support for Thermal Expansion and Centering

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Solution Overview

Problem

Existing piloted valves are limited by the choice of materials for the diaphragm, which can be incompatible with certain fluids and pressure or temperature conditions, and are not flexible enough to accommodate thermal expansion, restricting their applications.

Innovation Solution

A valve design that uses a support member with a cylindrical bore and a pan-shaped support member with an S-shaped circumferential wall, allowing the diaphragm to expand radially and thermally, while maintaining centering and stability through a sliding mechanism and bleed apertures to control pressure differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the diaphragm is made from rigid materials to maintain structural stability, then the valve can withstand high pressure and temperature conditions, but the choice of materials is limited and incompatible with certain fluids

Engineering Contradiction:
Improvestructural stabilityVSAvoidmaterial compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The diaphragm is segmented into a flexible membrane portion and a rigid support member portion. The flexible membrane allows material compatibility with various fluids while the rigid support member provides structural stability for high pressure and temperature conditions. This segmentation enables combining materials with different properties in a single functional component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The diaphragm uses a composite structure combining flexible material (such as rubber or polymer) with a rigid support member (such as a metal or reinforced ring). This composite approach allows the flexible portion to contact fluids without degradation while the rigid portion maintains structural integrity under extreme conditions, expanding both material compatibility and reliability.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the diaphragm is made from rigid materials to maintain centering, then the valve operation is stable, but thermal expansion is restricted causing operational failures

Engineering Contradiction:
Improvecentering stabilityVSAvoidthermal expansion tolerance
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The diaphragm is divided into a flexible membrane that can expand thermally and a rigid support member that maintains centering. The flexible portion absorbs thermal expansion while the rigid support member with its guide structure ensures the diaphragm remains centered during operation, resolving the conflict between thermal tolerance and centering stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support member is designed with specific geometric parameters (such as guide groove dimensions and support surface areas) that allow the diaphragm to maintain centering across a range of thermal expansion states. By optimizing these parameters, the valve achieves stable operation despite temperature variations causing diaphragm expansion or contraction.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If the diaphragm is made flexible to allow thermal expansion, then temperature tolerance is improved, but the diaphragm cannot maintain proper centering and positioning

Engineering Contradiction:
Improvethermal expansion accommodationVSAvoidcentering maintenance
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The support member acts as an intermediary between the flexible diaphragm and the housing. It provides a guide structure that constrains the flexible diaphragm's movement, ensuring the diaphragm remains centered while allowing thermal expansion. The support member mediates between the need for flexibility and the need for positional stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The diaphragm uses a flexible membrane or thin film structure that can expand and contract thermally while the support member provides guiding surfaces that maintain centering. The flexible shell design allows thermal accommodation while the supported configuration ensures proper positioning during valve operation.

Inventive Principle:
Principle #30Flexible shells and thin films

4Ease of manufacture

If limited material choices are used for the diaphragm, then manufacturing and design are simplified, but the range of applications is restricted

Engineering Contradiction:
Improvedesign simplicityVSAvoidapplication range
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The diaphragm is segmented into a simple flexible membrane portion and a support member portion. This segmentation allows the membrane to be made from various fluid-compatible materials while the support member provides standardized structural support, simplifying manufacturing while expanding application range through material selection flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support member serves multiple functions: providing structural support, maintaining centering, guiding diaphragm movement, and accommodating thermal expansion. This multi-functional design allows the same basic structure to work with various diaphragm materials, expanding application range without complicating the overall manufacturing process.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables the use of a wider range of materials for the diaphragm, ensuring reliable centering and movement control, thus expanding the valve's application range and reducing production costs by allowing cheaper, non-reinforced polymer or rubber materials to be used.

Implementation Method 1

The support member can slide along an inner surface of the housing when the main valve opens or closes

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

absorption of a refrigerant or other fluids

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

thermally expand or shrink

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

the pressure differences between the pilot chamber and the inlet/outlet can be changed to indirectly open the main valve

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3133326B1valve
Publication Date: 2021.12.15 DANFOSS AS
  • EP3133326B1 patent drawingFigure 1
  • EP3133326B1 patent drawingFigure 2~3
  • EP3133326B1 patent drawingFigure 4~5

AI summary

The invention relates to a valve (1) comprising a main valve (2), a pilot valve (3), a housing (4), an inlet (5) and an outlet (8). Opening and closing of the main valve (2) is controlled by the pilot valve (3). A pilot valve seat (10) is arranged in a diaphragm (6). A pilot chamber (11) is arranged in the housing (4) separated from the inlet (5) and the outlet (8) by the diaphragm (6). Task of the invention is to provide a valve with a lower cost. According to the invention a support member (17) supports the diaphragm (6), wherein the support member (17) is guided in the housing, and wherein a radial gap (26) is arranged between the radially outer end of the diaphragm (6) and the housing (4) in a radial direction perpendicular to the opening direction of the pilot valve (3). Thereby, a cheaper, less resistant material for the diaphragm can be used.