PTC Flat-Tube Heater Assembly for Safe Heat Dissipation
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Solution Overview
Problem
Existing electric heating devices for motor vehicles face inefficiencies due to poor heat dissipation and safety concerns, particularly when using PTC elements with corrugated fin elements, leading to high resistance and reduced power output.
Innovation Solution
The design incorporates a plastic frame with corrugated fin elements in metallic contact with flat tubes, where an external spring applies pretension to ensure good heat transfer and uses a conductor element to maintain the same polarity across multiple flat tubes, along with a sealing system to prevent electrical and thermal issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring element is used to apply tension to contact plates against the PTC element, then electrical contact is ensured, but heat dissipation on the spring element side deteriorates due to poor thermal conductivity and prevention of full contact between insulation and flat tube
Solution Approach 1:
The spring element is completely removed from the design. Instead, the patent uses direct thermal contact between the insulation layer and the flat tube surface, allowing the insulation to serve dual purposes: electrical insulation and thermal conduction pathway. This extraction eliminates the thermal resistance introduced by the spring element while maintaining electrical contact through the conductive insulation material.
Solution Approach 2:
The insulation layer is designed to perform multiple functions simultaneously: providing electrical insulation between the flat tube and contact plates, while also serving as a thermal conduction pathway due to its conductive properties. This multi-functionality resolves the contradiction by making the same component responsible for both electrical isolation and thermal transfer.
2Power
If high voltage is applied to PTC elements, then heating power is increased, but safety requirements deteriorate due to risk of electrical insulation failure and potential short circuits
Solution Approach 1:
The insulation layer acts as an intermediary component between the high-voltage flat tube and the metal contact plates/housing. This intermediate layer provides electrical isolation that prevents direct contact and potential short circuits, enabling safe operation at high voltages while maintaining the necessary electrical connections through its conductive properties.
Solution Approach 2:
The patent employs thin film insulation material that conforms to the flat tube surface, providing comprehensive electrical isolation. This flexible insulating layer ensures complete coverage and reliable insulation against high voltage, preventing electrical breakdown while allowing close proximity of conductive components.
3Power
If multiple flat tubes are used to increase heating capacity, then power output is improved, but device complexity deteriorates due to multiple insulation and connection requirements
Solution Approach 1:
Multiple flat tubes are bundled together with their insulation layers in close proximity, forming an integrated heating assembly. The contact plates are designed to simultaneously contact multiple insulated flat tubes, reducing the number of separate connection structures needed. This merging approach increases heating capacity while minimizing the complexity growth that would normally accompany multiple independent components.
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 configuration enhances heat dissipation and safety by ensuring uniform heat discharge and reliable insulation, improving the efficiency and performance of the electric heating device while meeting safety requirements.
Implementation Method 1
The heat-generating element has a flat tube in which at least one PTC element is arranged. The PTC element is located between two contact plates, which are energized with opposite polarities and are therefore assigned opposite polarities in order to heat the PTC element.
Implementation Method 2
The corrugated fin element typically rests against the heat-generating element with good thermal conductivity.
Implementation Method 3
Insulation is provided between the inner circumferential surface of the flat tube and the contact plates. This insulation is located on the outside of the PTC element.
Data Source
Figure 1
Figure 2~9
Figure 3~6
AI summary
The present invention relates to an electric heating device designed with improved electrical safety, comprising a frame (2) in which a power section (10) is arranged, the power section having corrugated fin elements (12) and heat-generating elements, each comprising at least one PTC element (20) arranged between contact plates (22), which is covered on the outside by insulation (24) and received in a flat tube (14), wherein the corrugated fin elements (12) bear against the outside of the flat tubes (14), wherein several flat tubes (14) are sealed at their connection side and passed through a control housing (82), and wherein a conductor element (70) is provided in the control housing (82) which electrically connects several flat tubes (14) to each other.