Series-Connected Preform Heaters for Uniform Thermal Profiles

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Solution Overview

Problem

Existing heat treatment units face challenges in uniformly applying a thermal profile to preforms due to practical lags in synchronizing heating elements on opposite walls, leading to irregularities in container production, especially when multiple rows of preforms circulate in parallel.

Innovation Solution

Connecting the first and second heating elements of a pair across the enclosure in series with the same current source ensures identical current flow and simultaneous power adjustment, ensuring uniform heating power delivery to preforms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If heating elements on opposite walls are controlled synchronously to vary heating power, then heating uniformity should be improved, but practical lag between applying setpoints to heating elements on different walls causes thermal profile irregularities

Engineering Contradiction:

Improvethermal profile uniformityVSAvoidcontrol lag between walls

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent connects heating elements on opposite walls in series to the same current source, merging their electrical control into a single circuit. This ensures that both heating elements receive identical current simultaneously, eliminating the control lag that occurs when separate power sources are used. The series connection physically couples the heating elements so they respond uniformly to current variations.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical/electrical control system with separate power sources and switches with a unified electrical circuit using series connection. By substituting the complex multi-source control mechanism with a simple series circuit, the system achieves automatic synchronization of heating elements without requiring complex timing control mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If separate current sources are used for heating elements on each wall to allow independent control, then control flexibility is improved, but heating uniformity between opposite walls deteriorates due to synchronization lag

Engineering Contradiction:

Improveindependent control flexibilityVSAvoidheating uniformity between walls

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent merges the control of heating elements on opposite walls by connecting them in series to the same current source. This single unified control approach eliminates the synchronization lag inherent in using separate current sources, ensuring that both walls receive identical heating power simultaneously while maintaining the ability to control the overall heating process.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If multiple current sources are used to control heating elements, then control precision is improved, but energy consumption increases due to redundant power sources

Engineering Contradiction:

Improvecontrol precisionVSAvoidenergy consumption from redundant power sources

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent reduces the number of current sources by connecting heating elements in series, allowing a single current source to control multiple heating elements. This eliminates redundant power sources and reduces energy consumption while maintaining control precision through the unified series circuit that ensures identical current flow to all heating elements.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single current source in the series connection serves multiple heating elements simultaneously, making it a universal power source for the entire heating system. This multi-functional approach eliminates the need for separate dedicated power sources for each heating element, reducing overall energy consumption while maintaining control capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 guarantees uniform heating profiles for preforms, reduces energy consumption by halving the number of power sources, and enhances production consistency by eliminating differences in heating characteristics between rows.

Implementation Method 1

each heating element being supplied with electricity by a current source

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4470752B1Unit for the thermal treatment of preforms, comprising heating elements connected in series

Publication Date: 2025.12.24 SIDEL PARTICIPATIONS SAS

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AI summary

The preform (2) heat treatment unit (1) comprises an enclosure delimited by a first wall (4) and a second wall (8), the first wall (4) comprising at least one first heating element (6) and the second wall (8) comprising at least one second heating element (10), forming, with the first heating element (6), a pair of heating elements, the first heating element (6) and the second heating element (10) extending at least partially opposite each other on either side of the enclosure, each heating element (6, 10) being electrically supplied by a current source (24). The first and second heating elements (6, 10) of said pair of heating elements are electrically connected in series to the same current source (24).