Forehearth Temperature Control via Ambient Air Feedback

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Solution Overview

Problem

Existing glassware manufacturing methods for controlling forehearth temperature are costly due to the use of in-glass thermocouples, which require high capital investments and are sensitive to ambient air temperature changes, leading to variations in glass temperature.

Innovation Solution

A system and method that utilize a combustion air blower, manifold, and controller to maintain a constant mass flow rate of the combustible air/fuel mixture, adjusting burner output based on air temperature and pressure signals, including a moving average temperature compensation to stabilize glass temperature across varying ambient conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If in-glass thermocouples are used to control forehearth temperature, then temperature control accuracy is improved, but capital investment cost increases

Engineering Contradiction:
Improvetemperature control accuracyVSAvoidcapital investment cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces ambient air temperature as an intermediary parameter to indirectly control and predict glass temperature changes. Instead of directly measuring glass temperature with expensive in-glass thermocouples, the system uses cheap ambient air temperature sensors to detect environmental changes and adjusts burner output accordingly, achieving accurate temperature control without direct glass contact measurement

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a simplified copy of the temperature control function by measuring ambient air temperature instead of glass temperature directly. The air temperature serves as a proxy indicator that correlates with glass temperature trends, allowing the control system to predict and adjust for temperature changes without requiring complex direct measurement infrastructure

Inventive Principle:
Principle #26Copying

2Measurement precision

If in-glass thermocouples are used to control forehearth temperature, then temperature control accuracy is improved, but sensitivity to ambient temperature changes increases

Engineering Contradiction:
Improvetemperature control accuracyVSAvoidsensitivity to ambient temperature changes
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of ambient temperature sensitivity into a beneficial control mechanism. Instead of treating ambient temperature changes as disturbances to be resisted, the system uses them as early warning signals that trigger preemptive burner adjustments, turning an adverse factor into a useful predictive input for maintaining stable glass temperature

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If burner output is adjusted based on ambient air temperature, then glass temperature stability is improved, but system complexity increases

Engineering Contradiction:
Improveglass temperature stabilityVSAvoidsystem complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control loop where ambient air temperature measurements are continuously monitored, processed through control logic that considers the relationship between air and glass temperature, and used to adjust burner output. This closed-loop feedback mechanism automatically compensates for environmental variations while maintaining relatively simple system architecture

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the control parameter from direct glass temperature measurement to ambient air temperature measurement. By monitoring and responding to changes in air temperature parameters, the system achieves glass temperature stabilization through a simpler measurement and control approach that avoids the complexity of direct glass temperature sensing

Inventive Principle:
Principle #35Parameter changes

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 reduces the effect of ambient temperature changes on glass temperature by approximately 75%, maintaining consistent glass temperatures despite significant ambient temperature fluctuations, thereby improving temperature control efficiency and reducing capital costs.

Implementation Method 1

a combustion air blower for delivering ambient air under pressure to the manifold

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

a temperature sensor operatively coupled downstream of the blower for providing to the controller a signal indicative of temperature of air delivered to the manifold by the blower

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

at least one burner disposed in the forehearth for heating glass in the forehearth

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

a combustion air blower for delivering ambient air under pressure to the manifold

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3121153B1Method for controlling temperature in a forehearth
Publication Date: 2020.01.15 OWENS BROCKWAY GLASS CONTAINER INC
  • EP3121153B1 patent drawingFigure 1~2
  • EP3121153B1 patent drawingFigure 3~5
  • EP3121153B1 patent drawingFigure 6

AI summary

Systems and methods are provided for controlling temperature in a glass forehearth (11) which includes at least one burner (24) disposed in the forehearth, a manifold (22) coupled to the burner, a combustion fuel supply (26) coupled to the burner, a combustion air blower (20) for delivering ambient air under pressure to the manifold. In a method, the burner pressure is controlled as a function of a nominal burner pressure curve generated as a function of the amount of cooling air supplied to the manifold. In a system, there is provided a controller (30) coupled to the burner for controlling operation of the burner. The system may include a temperature sensor (36) operatively coupled downstream of the blower for providing to the controller a temperature signal indicative of temperature of air delivered to the manifold by the blower. The controller may be responsive to the temperature signal for controlling operation of the burner as a function of current temperature of air fed to the manifold. Operation of the burner may also be controlled as a function of an average air temperature over a preceding time duration.