Valve Body Casting With Corrosion-Resistant Internal Surfaces

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Solution Overview

Problem

Control valve components, particularly valve bodies, are susceptible to corrosion, which affects the quality of the end product and is costly to repair or replace, with existing methods either requiring expensive corrosion-resistant materials or time-consuming welding processes.

Innovation Solution

A method involving additive manufacturing to form a layer of corrosion-resistant material on internal surfaces of a valve body casting during the sand casting process, where a core with external corrosion-resistant material is used, allowing the molten metal to bind with it, creating a corrosion-resistant interior surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire valve body is manufactured out of corrosion resistant material, then corrosion resistance is improved, but material cost increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidamount of corrosion resistant material
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by providing corrosion resistant material only on the internal surfaces of the valve body where corrosion occurs, rather than using it throughout the entire valve body. This is achieved by placing a coating or layer of corrosion resistant material on the inner surface during the casting process, thus protecting against corrosion while using minimal amounts of expensive corrosion resistant material.

Inventive Principle:
Principle #3Local quality

2Reliability

If a layer of corrosion resistant material is welded on the internal surfaces, then corrosion resistance is improved, but manufacturing time and complexity increase

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by incorporating the corrosion resistant material during the initial casting process rather than adding it through a separate welding operation after the valve body is manufactured. The corrosion resistant material is placed on the internal surfaces as the molten metal is poured into the mold, integrating the protective layer formation into the base manufacturing process and eliminating the need for subsequent welding operations.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If welding is used to add corrosion resistant material, then corrosion resistance is improved, but manufacturing precision decreases due to imperfections

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidsurface quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical welding process with a casting-based approach where corrosion resistant material is deposited or formed on the internal surfaces as the molten metal fills the mold. This substitution eliminates the heat-affected zone, distortion, and imperfections associated with welding, while still achieving a bonded layer of corrosion resistant material on the internal surfaces through the casting process itself.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enhances corrosion resistance of valve body internal surfaces, reducing maintenance needs and extending the service life of control valves while minimizing material and time costs compared to traditional methods.

Implementation Method 1

forming a layer of a second material (that has a higher corrosion resistance than the first material) on one or more internal surfaces of the valve body casting, the layer of the second material being formed by applying, using an additive manufacturing technique, the second material to or on one or more externals surface of a core

Methodology Applied
Scientific EffectAdditive manufacturing: 3D Printing

Implementation Method 2

performing a casting process, using a first molten metal material poured into a molding box, to produce a valve body casting made of this first material

Methodology Applied
Scientific EffectCasting:

Data Source

PatentEP3455528B1Method for manufacturing a valve body having one or more corrosion-resistant internal surfaces
Publication Date: 2024.03.20 FISHER CONTROLS INT LLC
  • EP3455528B1 patent drawingFigure 1
  • EP3455528B1 patent drawingFigure 2

AI summary

A method of manufacturing a valve body having one or more corrosion-resistant internal surfaces. The method involves performing a casting process, which includes pouring a first material into a mold box, to produce a valve body casting made of the first material. During the casting process, a layer of a second material is formed on one or more internal surfaces of the valve body casting, the second material having a higher corrosion resistance than the first material, by: (1 ) applying, with an additive manufacturing technique, the second material to one or more external surfaces of a core, and (2) inserting the core into the mold box. A portion of the first material binds to the second material on the one or more external surfaces of the core while the first material is poured into the mold box.