Retractable Ignition System for Burner Reliability

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Solution Overview

Problem

Existing burner ignition systems are unreliable due to frequent re-ignition requirements and exposure to harsh environments, leading to igniter damage and reduced reliability.

Innovation Solution

A retractable ignition system with a high voltage electrode and actuator, where the igniter is slidably mounted within a burner's flow passage, allowing for pneumatically or manually controlled advancement and retraction, and a slidable seal to protect the igniter from damage, with a control system to manage high voltage and gas flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the igniter is left in the furnace during burner operation, then the igniter is exposed to intense radiation and soot leading to damage, but removing it requires frequent maintenance and replacement

Engineering Contradiction:

Improveigniter reliabilityVSAvoidexposure to radiation and soot

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The igniter is made movable between a retracted position (protected from harmful radiation and soot during burner operation) and an advanced position (where it can initiate ignition). This dynamic positioning resolves the contradiction by allowing the igniter to be both protected during operation and functional during ignition, eliminating the need for frequent maintenance while maintaining reliability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The ignition system is separated from the main burner assembly, allowing the igniter to be independently positioned. The igniter can be retracted into a protected position within the burner body or housing, isolating it from harmful environmental factors while maintaining its ignition capability when needed.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the igniter is positioned to initiate spark at the appropriate location, then proper ignition is achieved, but properly locating an igniter is difficult with existing external igniters

Engineering Contradiction:

Improveignition initiationVSAvoidigniter location

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The igniter is made movable along the flow passage to dynamically position itself at the optimal ignition location. This allows the igniter to be advanced to the precise point where fuel and oxidizer mix in flammable proportions, ensuring reliable ignition initiation while simplifying the positioning process through mechanical movement rather than complex external adjustment.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The igniter is nested within the flow passage of the burner, allowing it to be precisely positioned at various locations along the passage. This nested configuration enables the igniter to reach the optimal ignition point within the fuel-oxidizer mixing zone while being protected by the surrounding passage structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If the igniter is made retractable with actuator and seal, then protection from damage is improved, but device complexity increases

Engineering Contradiction:

Improveigniter protectionVSAvoidactuator and seal mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A pneumatic actuator is used to move the igniter between retracted and advanced positions. This pneumatic mechanism provides reliable protection by automatically retracting the igniter during burner operation and advancing it for ignition, achieving robust protection while using a relatively simple and well-established actuation technology.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

A flexible seal is used to maintain the sealed environment around the igniter while allowing it to move between positions. The flexible seal protects the igniter from harmful factors during retraction while accommodating the necessary movement for ignition, providing effective protection without requiring complex rigid sealing mechanisms.

Inventive Principle:

Principle #30Flexible shells and thin films

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 system ensures reliable ignition while protecting the igniter from overheating and damage, maintaining performance over thousands of cycles and reducing maintenance needs.

Implementation Method 1

a high voltage electrode surrounded by an insulator and extending beyond the insulator to form a tip end of the igniter... across which arcing can occur

Methodology Applied

Scientific EffectElectrical arc: Electric Arc

Implementation Method 2

the actuator is a bi-directional pneumatic actuator configured to pneumatically advance and pneumatically retract the igniter

Methodology Applied

Scientific EffectPneumatics:

Data Source

PatentUS9273867B2Retractable ignition system

Publication Date: 2016.03.01 AIR PROD & CHEM INC

AI summary

An integrated retractable burner ignition system including a burner having an outlet face and a flow passage including a front end substantially coincident with the outlet face of the burner and a gas inlet positioned rearward from the front end of the flow passage, an igniter including a high voltage electrode surrounded by an insulator and extending beyond the insulator to form a tip end of the igniter, the igniter being mounted slidably within the flow passage, an actuator connected to a rear portion of the igniter and configured to advance and retract the igniter within the flow passage, and a slidable seal between the igniter and the flow passage, the seal being positioned rearward of the gas inlet of the flow passage and frontward of the rear portion of the igniter.