Heating Power Adjustment for Plastic Preforms

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Solution Overview

Problem

Existing heating devices for plastic preforms cannot vary the speed while maintaining constant preform temperatures, as slower transport speeds increase residence time, leading to inconsistent heating.

Innovation Solution

Regulating the heating power of each heating device individually based on transport speed, reducing power at slower speeds and increasing it at faster speeds to maintain consistent energy input and temperature profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the transport speed of plastic preforms through the heating device is reduced to increase production flexibility, then the residence time of preforms in the heating device increases, but the heating temperature becomes inconsistent and exceeds the required temperature

Engineering Contradiction:
Improveproduction speed variabilityVSAvoidpreform heating temperature consistency
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The heating device dynamically adjusts the operating state of individual heating zones based on real-time transport speed feedback. When transport speed changes, the control system modifies the power output of specific heating lamps or zones to compensate for changes in residence time, maintaining consistent preform temperature at the exit regardless of speed variations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the heating parameters (power output, temperature setpoint) of individual heating zones as a function of transport speed. At lower speeds, the residence time increases, so the heating power is reduced proportionally to prevent overheating. At higher speeds, residence time decreases, requiring increased heating power to achieve the same temperature outcome.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the transport speed is increased to boost productivity, then the production rate improves, but the residence time of preforms in the heating device decreases leading to insufficient heating

Engineering Contradiction:
Improveproduction rateVSAvoidpreform heating temperature adequacy
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The heating device dynamically increases the power output of heating zones when transport speed increases. The control system detects higher speeds and compensates for the reduced residence time by delivering more intense heating, ensuring that preforms still reach the required temperature despite the faster throughput.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system adjusts heating parameters inversely to transport speed changes. When speed increases, heating power is increased proportionally to maintain the same energy input per preform. This dynamic parameter adjustment ensures consistent heating quality across the full range of production speeds.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If fixed heating power is used in the heating device, then the device structure remains simple, but the heating temperature cannot be maintained constant when transport speed varies

Engineering Contradiction:
Improveheating control system complexityVSAvoidpreform temperature consistency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The heating device incorporates a feedback control system that continuously monitors transport speed and adjusts heating power accordingly. Sensors detect the actual speed of preform transport, and this information feeds back to the control system, which then modifies the heating output to maintain constant temperature at the heating device exit, enabling speed variability without compromising heating quality.

Inventive Principle:
Principle #23Feedback

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

Enables variable production rates in blow molding machines by maintaining consistent preform temperatures regardless of transport speed, allowing for efficient energy use and flexible output capacity even in blocked systems.

Implementation Method 1

heating devices H1...H12 arranged along the transport path T... heated to a predetermined temperature by means of a plurality of heating devices H1...H12 arranged along the transport path T

Methodology Applied
Scientific EffectRadiant heating: Thermal Radiation

Data Source

PatentEP4197740B1Device and method for heating plastic pre-forms with adjustment of the heating power
Publication Date: 2024.12.18 KRONES AG
  • EP4197740B1 patent drawingFigure 1~2
  • EP4197740B1 patent drawingFigure 3~4
  • EP4197740B1 patent drawingFigure 5

AI summary

A method for heating plastic preforms (10), wherein the plastic preforms are transported within a heating device (5) along a predetermined transport path (T) and are heated to a predetermined temperature during this transport by means of a plurality of heating devices (H1...H12) arranged along the transport path (T), and wherein the heating power of the heating devices (H1...H12) acting on the plastic preforms (10) is variable. According to the invention, the heating power of the heating devices (H1...H12) acting on the plastic preforms (10) is controlled as a function of the transport speed of the plastic preforms (10).