Diaphragm Valve Seat Ring Structure for High-Temperature Sealing

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Solution Overview

Problem

Diaphragm valves in semiconductor manufacturing processes face issues with valve seat deformation and durability at high temperatures, leading to sealing failures and variations in Cv values, and existing solutions either lack support for soft material valve seats or narrow the flow path, reducing flow rates.

Innovation Solution

A diaphragm valve design featuring a seat ring with a flange section and press-fitting groove, where the valve seat is press-fitted with a large diameter section to prevent deformation and a female screw for easy extraction, ensuring stable high-temperature operation and easy replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a valve seat made of soft material such as PFA is used at high temperature, then sealing property is improved, but the valve seat is easily deformed toward the inner peripheral surface side, lowering the top portion and deteriorating diaphragm durability

Engineering Contradiction:

Improvesealing propertyVSAvoidvalve seat shape stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention applies different material properties to different parts of the valve seat structure. The valve seat itself is made of soft material (PFA) for sealing, while the support structure (outer wall section and seat ring) is made of rigid material (resin or metal) for structural support. This local differentiation allows the soft valve seat to maintain sealing properties while the rigid support prevents deformation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses composite construction combining soft sealing material (PFA valve seat) with rigid support material (resin or metal outer wall section and seat ring). This composite structure enables the valve seat to provide sealing while being supported by the rigid structure to prevent deformation under high temperature and pressure conditions.

Inventive Principle:

Principle #40Composite materials

2Device complexity

If the valve seat is press-fitted directly into the body without support structure, then device complexity is reduced, but the valve seat is easily crushed and deformed under high temperature and pressure

Engineering Contradiction:

Improvevalve seat structure complexityVSAvoidvalve seat durability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The invention introduces an intermediary support structure (outer wall section and seat ring) between the valve seat and the body. The outer wall section provides the press-fitting interface with the body, while the seat ring provides additional support to the valve seat. This intermediary structure prevents direct contact and deformation of the valve seat while maintaining a relatively simple overall design.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If a male screw extraction tool is used to remove the valve seat, then ease of operation is improved, but fine chips are generated that may contaminate the flow path

Engineering Contradiction:

Improvevalve seat extraction easeVSAvoidflow path contamination

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

Instead of using a male screw extraction tool that threads into the valve seat and pulls it out (which generates chips), the invention inverts the approach by providing a female screw section in the seat ring. The extraction tool has a male screw that threads into this female screw, allowing the entire seat ring assembly to be removed as one piece without generating chips from the valve seat itself.

Inventive Principle:

Principle #13The other way round (Inversion)

4Manufacturing precision

If the inner diameter of the sleeve is made smaller than the inner diameter of the primary-side opening section, then the flow path is narrowed for better control, but the flow rate decreases and Cv value is reduced

Engineering Contradiction:

Improveflow control precisionVSAvoidflow rate

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention removes the sleeve component from the design entirely. By eliminating the sleeve, the flow path is not narrowed, and the full flow capacity of the primary-side opening section is maintained. The valve seat directly defines the flow characteristics without the additional constriction of a sleeve, thereby maintaining higher flow rates and Cv values.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS11982361B2Diaphragm valve and method for exchanging valve seat thereof

Publication Date: 2024.05.14 KITZ SCT CORP

AI summary

A diaphragm valve includes an outer wall section for valve seat mounting provided in a primary-side opening section, a stepped section provided on the inner periphery of the outer wall section, a seat ring press-fitted into and fixed to the stepped section, a flange section provided in the seat ring, and a press-fitting groove for valve seat mounting configured with a space between the seat ring and the outer wall section and the flange section, in which a valve seat press-fitted into and fixed to the press-fitting groove has an upper portion slightly protruding in a state where an extension section covers a position in the vicinity of a top portion of the outer wall section and an extension section the inner periphery of which is decreased in the upper portion of the valve seat covers a position in the vicinity of a top portion of the seat ring.