Slide Valve Tight Shutoff Design to Prevent Disc Sticking

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Solution Overview

Problem

Slide gate valves used in fluid catalytic cracking processes face challenges due to extreme temperature fluctuations, erosion, and high pressure differentials, leading to premature failures and wear, especially when handling catalyst particles of varying sizes and directions of flow.

Innovation Solution

A slide valve design featuring a valve disc and disc receptacle with inclined wedges for sealing engagement, an actuating stem coupled to a hydraulic or electric drive, and a flexible connection to prevent bending forces, allowing for both tight shutoff and controlled gas flow while preventing particle flow through an air gap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a slide gate valve is used for catalyst control in fluid catalytic cracking, then flow control capability is achieved, but premature failure occurs due to extreme temperature fluctuations, erosion, and high pressure differentials

Engineering Contradiction:

Improvevalve reliabilityVSAvoidtemperature fluctuations, erosion, pressure differentials

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The valve disc employs a composite structure with a metal substrate providing mechanical strength and a ceramic coating (such as alumina or zirconia) providing erosion and heat resistance. This composite material approach allows the valve to withstand the harsh operating conditions including catalyst particle erosion, extreme temperature fluctuations, and high pressure differentials without premature failure.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The sealing mechanism incorporates a compliant sealing surface that deforms elastically under high contact pressure to ensure tight sealing. This elastic deformation acts as a cushioning mechanism that accommodates surface irregularities and maintains sealing effectiveness despite thermal expansion and erosion, preventing leakage before it can occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the valve disc is pressed tightly against the orifice plate for sealing, then shutoff capability is improved, but sticking and wear increase due to high contact pressure and temperature

Engineering Contradiction:

Improveshutoff capabilityVSAvoidsticking and wear

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The sealing mechanism replaces traditional mechanical friction-based sealing with a pressure-induced elastic deformation mechanism. The sealing surface is designed to deform elastically under controlled contact pressure, creating a tight seal through material compliance rather than mechanical interlocking. This reduces sticking tendencies while maintaining effective shutoff capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The contact pressure and temperature parameters at the sealing interface are precisely controlled within optimal ranges. The sealing surface geometry and material properties are selected to ensure that under normal operating conditions, the contact pressure is sufficient for tight sealing but not excessive to cause sticking. Thermal expansion is accounted for in the design to maintain appropriate clearance and contact pressure across the temperature range.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the valve allows gas flow through a small air gap, then gas flow control is achieved, but particle flow control becomes difficult

Engineering Contradiction:

Improvegas flow controlVSAvoidparticle flow control

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The valve incorporates different gap characteristics at different locations: a controlled air gap in the central flow region to allow gas flow, and tight sealing contact at the periphery to prevent particle leakage. The sealing surface geometry is designed with a central depressed area that maintains the air gap while peripheral regions provide tight contact sealing, achieving selective flow control for different phases.

Inventive Principle:

Principle #3Local quality

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

The design enhances the durability and reliability of slide gate valves by preventing sticking and wear, maintaining effective sealing and flow control across a wide temperature range and high pressure differentials, reducing premature failures and extending valve lifespan.

Implementation Method 1

The valve disc and the orifice plate include inclined wedges that engage each other to press the valve disc into sealing engagement with the orifice plate

Methodology Applied

Scientific EffectWedge: Wedge

Implementation Method 2

The actuating stem is flexibly connected to the valve disc to prevent bending forces

Methodology Applied

Scientific EffectFlexibility: Elasticity

Data Source

PatentUS11525517B2Catalyst control and withdrawal valve with tight shutoff capability

Publication Date: 2022.12.13 BLAC INC

AI summary

A slide valve having a valve disc that is slidably movable between a fully-retracted fully-open position and a fully-extended fully-closed tight shutoff position by an actuating stem. The actuating stem is flexibly coupled to the valve disc. The valve disc is selectively modulated between the fully-extended fully-closed tight shutoff position and a partially-retracted non-tight shutoff position to prevent sticking of the valve disc in the fully-extended fully-closed tight shutoff position.