Bonnet And Stuffing Box Bushings for Corrosion-Resistant Valve Sealing

Solution Overview

Problem

Bonnet and stuffing box assemblies in fluid pipeline systems face inefficiencies due to precision machining requirements and the use of non-corrosion-resistant materials, leading to slowed manufacturing, increased rust, and potential health risks, especially in drinking water applications.

Innovation Solution

A bushing assembly comprising a stuffing box bushing and a bonnet bushing, both precision-machined from corrosion-resistant materials like bronze or stainless steel, is integrated into the bonnet and stuffing box assembly to enhance manufacturing efficiency and prevent rust, with a stem extending through the bushing bore to actuate valves while maintaining a watertight seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If precision machining is performed on large components like bonnet and stuffing box, then optimal engagement with the stem is achieved, but manufacturing efficiency significantly decreases

Engineering Contradiction:

Improvestem engagement precisionVSAvoidmanufacturing efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention divides the precision-machining task from the casting task by introducing separate bushing components. The bushings are precision-machined independently and then assembled into the cast bonnet and stuffing box, allowing each component to be optimized separately rather than requiring the entire assembly to be precision-machined.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bushings serve as intermediary components between the cast bonnet/stuffing box and the stem. These bushings are precision-machined to provide the necessary engagement surfaces for the stem, while the main bonnet and stuffing box can be manufactured by less precise casting methods.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If non-corrosion-resistant materials like iron are used for bonnet and stuffing box, then manufacturing cost is reduced, but rust develops quickly decreasing functionality and lifespan

Engineering Contradiction:

Improvemanufacturing costVSAvoidcorrosion resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention uses composite construction where the bonnet and stuffing box are cast from cost-effective materials (such as iron or ductile iron) while the bushings are made from corrosion-resistant materials (such as bronze or stainless steel). This composite approach combines the economic benefits of cast iron with the corrosion resistance of bronze/stainless steel bushings.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention applies corrosion-resistant material properties locally where they are most needed - in the bushings that are in direct contact with water and the stem. The main bonnet and stuffing box body can use less expensive materials since they are not in direct contact with corrosive fluids.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If non-corrosion-resistant materials are used, then manufacturing cost is reduced, but health risks increase when rust is introduced into drinking water

Engineering Contradiction:

Improvemanufacturing costVSAvoidhealth risks from rust

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention uses composite construction where the bonnet and stuffing box are cast from cost-effective materials (such as iron or ductile iron) while the bushings are made from corrosion-resistant materials (such as bronze or stainless steel). This composite approach combines the economic benefits of cast iron with the corrosion resistance of bronze/stainless steel bushings.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention applies corrosion-resistant material properties locally where they are most needed - in the bushings that are in direct contact with water and the stem. The main bonnet and stuffing box body can use less expensive materials since they are not in direct contact with corrosive fluids.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11686406B2Method of using a bonnet and stuffing box assembly

Publication Date: 2023.06.27 MUELLER INT LLC

AI summary

Example aspects of a method of using a bonnet and stuffing box assembly and a method of manufacturing a bonnet and stuffing box assembly are disclosed. The method of using a bonnet and stuffing box assembly can comprise providing a stuffing box, a bonnet, a bushing assembly, and a stem, the stuffing box and the bonnet defining an assembly bore, the bushing assembly received in the assembly bore, the bushing assembly defining a bushing bore, and the stem received through the bushing bore; sealing the stem relative to the bushing assembly to prohibit fluid flow through the bushing bore; sealing the bushing assembly relative to the bonnet to prohibit fluid flow through the assembly bore; and turning the stem relative to the bushing assembly, bonnet, and stuffing box to actuate a valve.