Helical Screw Fluid Heater for Low-Resistance Heat Transfer
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Solution Overview
Problem
Existing electric heating devices for vehicles face challenges in providing cost-effective solutions that balance fluid heating efficiency with low flow resistance and heat transfer, while accommodating manufacturing tolerances and varying power availability.
Innovation Solution
An electric heating device with a helically wound flow channel defined by a screw in a cylindrical tube housing, featuring heating resistors within the screw's core and a compact design that allows for extended fluid flow paths with minimal dynamic pressure, using metal screws for efficient heat transfer and a porous plastic tube housing for improved insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the cross section of the flow channel is enlarged to achieve low flow resistance and high fluid throughput, then the flow resistance decreases, but the heat transfer area becomes smaller
Solution Approach 1:
The patent transforms the flow channel from a straight linear path into a helical three-dimensional path that winds around the screw core. This dimensional transformation allows the fluid to traverse a much longer path length within the same axial space, significantly increasing the heat transfer area without requiring a larger cross-sectional area, thereby maintaining low flow resistance while maximizing heat exchange surface.
Solution Approach 2:
The flow channel is nested within the helical structure of the screw, utilizing the screw's geometric form to create the heating pathway. The fluid flows through the helical channel that is effectively nested inside the screw body, allowing the heat transfer surface to be maximized within the compact screw geometry without increasing external dimensions or cross-sectional area.
2Loss of energy
If a screw made of metal is used to improve heat conductivity, then heat transfer efficiency increases, but the heat capacity becomes larger requiring more energy to heat up
Solution Approach 1:
The patent introduces a thermal insulation layer as an intermediary between the metal screw and the external environment. This insulation layer reduces parasitic heat losses to the surroundings, allowing the metal screw's high heat conductivity to be fully utilized for transferring heat to the fluid while minimizing the energy required to maintain the screw's temperature. The insulation acts as a mediator that directs thermal energy preferentially to the fluid rather than the environment.
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 solution enables efficient heat absorption and distribution to fluids with low flow resistance, accommodating manufacturing tolerances for cost-effective production and maintaining heating capability during intermittent power supply, while minimizing heat loss and ensuring uniform heating.
Implementation Method 1
Heat generated by the heating resistor is output via the screw to fluid flowing through the flow channel
Implementation Method 2
Due to the good heat conductivity of metals, heat generated by the heating resistor can then be forwarded efficiently and output to fluid in the flow channel
Implementation Method 3
The helical flow channel leads the fluid to be heated a number of times around the center of the screw, in which the thermal heat is generated, and thus enables a long flow path of the fluid
Implementation Method 4
Plastics have a relatively poor heat conductivity, and therefore heat losses to the surrounding environment can be kept low. In order to further improve the thermal insulation, the tube housing may have a multi-layered wall or a wall containing foam
Data Source
AI summary
The invention relates to a electric heating device for heating fluids, comprising at least one heating resistor, a screw, which defines a helical flow channel, and a tube housing, which surrounds the screw. In accordance with this disclosure, the screw has a core in which the at least one heating resistor is arranged.