Tubular Electric Heater with Segmented Unheated Connection Section
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Solution Overview
Problem
Existing electric tubular heaters face challenges in accommodating large conductor cross-sections in unheated areas, leading to difficulties in compaction and increased stress on machinery, as well as limitations in using materials like copper or nickel for connecting bolts due to annealing processes, which affect process reliability and tool lifespan.
Innovation Solution
The method involves producing electric heating devices with a multi-part tubular metal jacket, where the heated area is compressed in one part and the unheated area is created separately, allowing for optimized compaction and filling with insulating material, enabling the use of materials like copper or nickel for connecting wires and bolts without excessive thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a connecting wire or connecting bolt with larger cross-section is used in the unheated area, then the electrical connection is improved, but the compaction process becomes significantly more difficult and places enormous loads on compaction machines
Solution Approach 1:
The tubular metal casing is divided into multiple sections, with the unheated area formed as a separate section that is inserted into the heated area. This segmentation allows the unheated section containing the connecting wire/bolt to be manufactured independently with optimized dimensions, avoiding the need to compact the entire assembly with the large cross-section conductor, thereby reducing loads on compaction machines while maintaining reliable electrical connection
2Loss of energy
If copper or nickel is used for connecting bolts to reduce heat generation, then the thermal performance is improved, but the material cannot withstand annealing processes required for flexible heating elements
Solution Approach 1:
The connecting wire or connecting bolt is extracted as a separate component that is inserted into the unheated area of the heating element. This allows the use of copper or nickel for the connecting component to minimize heat generation at the connection point, while the main heating element can still undergo annealing processes. The separating structure protects the low-melting-point connecting material from excessive thermal stress during annealing
3Reliability
If the unheated area is created with connecting wire and connecting bolt, then the electrical connection is established, but the filling with electrically insulating material is hindered
Solution Approach 1:
The unheated area with the connecting wire or connecting bolt is manufactured as a separate section before being inserted into the heated area. This preliminary formation of the unheated section with optimized dimensions creates sufficient space for the connecting components while maintaining the ability to subsequently fill the heated area with electrically insulating material without obstruction, as the insulating material is applied after the connecting structure is in place
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 allows for improved compaction processes, easier filling with insulating material, reduced stress on machinery, and cost-effective production of electric heating devices with flexible unheated sections, enhancing process reliability and tool longevity.
Implementation Method 1
the electrical heating device has an unheated region within the multi-part tubular metal casing at at least one end, in which region the electrical current flows at least also through at least one connecting wire and/or at least one connecting sleeve and/or at least one connecting bolt
Implementation Method 2
They are characterized by the fact that the electric heating element is arranged within a tubular metal casing. It is electrically insulated radially from the tubular metal casing by embedding it in an electrically insulating but highly thermally conductive material
Implementation Method 3
embedding it in an electrically insulating but highly thermally conductive material, often magnesium oxide, boron nitride, or Al2O3
Data Source
Figure 1a
Figure 1b~1d
Figure 2
AI summary
A method for manufacturing an electric heating device (10) is provided, comprising an electric heating element (12, 12', 12") which is embedded inside a multi-part tubular metal sheath (11) in an electrically insulating material (16, 17), wherein the electric heating device (10) has, within the multi-part tubular metal sheath (11), at least one unheated area (U) at one end, in which, when the electric heating device (10) is operated, the electric current flows at least also through at least one connecting wire (13), and/or at least one connecting sleeve (14) and/or at least one connecting bolt (15) which is in electrical contact with the electric heating element (12, 12', 12"), and furthermore has a heated area (B).in which, during operation of the electric heating device (10), the electric current flows only through a section of the electric heating element (12) extending into the heated area (B), and an electric heating device (10) with a multi-part tubular metal jacket (11) that can be produced therewith.