Inductive Screw Machine Heating Zone Design
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Solution Overview
Problem
Existing screw machines experience high mechanical energy input and vibrations due to high mechanical forces in the plasticizing zone, leading to mechanical wear, and existing heating solutions are inefficient in heating plastic material effectively.
Innovation Solution
A screw machine design where the inductive heating device interacts with treatment elements made of electrically conductive ferromagnetic materials, while the housing sections are made of electromagnetically transparent non-magnetic materials, allowing for efficient energy input into the plastic material with minimal loss, reducing mechanical forces and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heating devices with electric resistance elements are used in housing sections, then heating capability is provided, but energy input efficiency is low and housing sections become hot
Solution Approach 1:
The patent replaces conventional electric resistance heating (Joule heating) with inductive heating. Instead of using heating elements embedded in housing sections, the invention uses a magnetic field generated by a coil to induce eddy currents directly in the treatment element, which then generates heat through its electrical resistance. This substitution eliminates the need for thermal conduction through housing sections and achieves direct energy input into the treatment element, dramatically improving energy efficiency.
Solution Approach 2:
The treatment element acts as an intermediary that converts electromagnetic energy from the coil into thermal energy through eddy currents. The magnetic field from the coil heats the treatment element, which then transfers heat to the plastic material through direct contact. This intermediary mechanism allows efficient energy transfer without heating the housing sections, solving the energy efficiency problem.
2Temperature
If high mechanical energy input is used in the plasticizing zone, then melting of plastic material is achieved, but mechanical forces cause vibrations and wear
Solution Approach 1:
The patent replaces mechanical energy input (through rotating screws and kneading elements) with electromagnetic energy input (through inductive heating). The coil generates a magnetic field that directly heats the treatment element and plastic material, eliminating the need for high mechanical forces. This substitution reduces vibrations and mechanical wear while achieving the same melting capability.
Solution Approach 2:
The invention changes the energy input parameter from mechanical energy to electromagnetic energy. By operating the coil at specific frequencies (e.g., 10-100 kHz), the system achieves resonant heating of the treatment element, dramatically reducing the mechanical energy required for plasticizing while maintaining effective melting.
3Loss of energy
If treatment elements are made of electrically conductive ferromagnetic materials, then inductive heating efficiency is high, but electromagnetic interaction with housing sections increases
Solution Approach 1:
The patent applies local quality by making only the treatment element electrically conductive and ferromagnetic, while the housing sections are made of electromagnetically transparent (non-conductive, non-magnetic) materials. This localized conductivity ensures that the magnetic field from the coil interacts only with the treatment element, generating eddy currents and heat precisely where needed, without causing electromagnetic losses or heating in the housing sections.
Solution Approach 2:
The treatment element serves as an electromagnetic intermediary that is selectively heated by the coil's magnetic field. Its ferromagnetic properties concentrate the magnetic flux and generate intense eddy currents locally, creating a focused heating zone. The electromagnetically transparent housing then prevents this electromagnetic energy from interacting with or heating the housing structure.
4Loss of energy
If housing sections are made of electromagnetically transparent materials, then energy input into housing is minimized, but structural strength and heat retention may be reduced
Solution Approach 1:
The patent employs composite material construction for the treatment element, combining electrically conductive ferromagnetic materials (for inductive heating) with thermally insulating materials (to retain heat in the plastic material). The housing sections use electromagnetically transparent materials that are structurally sound, creating a composite system that simultaneously achieves electromagnetic transparency, structural strength, and heat retention.
Solution Approach 2:
The system is segmented into distinct functional zones: the treatment element (conductive, ferromagnetic) for inductive heating, the plastic material zone for melting, and the housing sections (electromagnetically transparent) for structural support. This segmentation allows each component to be optimized for its specific function without compromising overall system performance.
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 enables efficient and loss-free heating of plastic material, reducing mechanical forces and wear in the screw machine, allowing for effective melting with minimal mechanical energy input.
Implementation Method 1
the inductive heating device (39) has a coil (40), an associated energy supply device (41) and a cooling device (42)
Implementation Method 2
the at least one treatment element is at least partially made of an electrically conductive material, so that the inductive heating device induces eddy currents in the at least one treatment element
Implementation Method 3
which in turn cause ohmic eddy current losses and heat the at least one treatment element
Implementation Method 4
The electrically conductive material is, in particular, ferrous and ferromagnetic. As a result, the at least one treatment element can be heated efficiently by ohmic eddy current losses and hysteresis losses
Implementation Method 5
the coil (40) is aligned with its coil axis or central longitudinal axis essentially in the direction of the axis of rotation or axes of rotation of the at least one treatment element shaft
Data Source
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AI summary
The invention relates to a screw machine (1) which has an inductive heating device (39) in order to prepare a plastic material (2). The inductive heating device (39) is used to heat the plastic material (2) in a heating zone (25). At least one housing portion (6) in the heating zone (25) is at least partly made of an electromagnetically transparent material which is non-magnetic and electrically non-conductive, whereas at least one treating element (33') is at least partly made of an electrically conductive material. The inductive heating device (39) generates a magnetic alternating field when preparing the plastic material (2), and the alternating field results in eddy current losses in the at least one treating element (33'), resulting in a heating of the at least one treating element (33'). The plastic material (2) is heated on the at least one heated treating element (33'), in particular until the plastic material is melted. The screw machine (1) allows a simple and efficient melting process of the plastic material (2), thereby allowing a substantial reduction of a mechanical energy input and thus a substantial reduction of a related wear of the screw machine (1).