Heating Cartridge Spring Element Heat Transfer
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Solution Overview
Problem
Existing heating cartridges in emission control systems face challenges in achieving effective heat transfer from PTC-based heating elements to protective tubes, especially when disassembly is required for replacement, as traditional heat transfer methods are insufficient and may damage the cartridge.
Innovation Solution
The use of a spring element with pressure surfaces pressed against the inside of the protective tube, which is prestressed to enhance heat transfer, and can be fastened to the heating cartridge or protective tube for easy installation and removal, while maintaining thermal contact through a meandering or corrugated design that adapts to thermal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the air gap is filled with highly thermally conductive material to improve heat transfer, then heat transfer efficiency is improved, but disassembly difficulty increases
Solution Approach 1:
The air gap is segmented into multiple regions by introducing discrete thermal conductive elements (such as metal foam segments or spaced conductive plates) rather than filling the entire gap continuously. This segmentation maintains thermal conduction pathways while preserving air gaps that allow for easy insertion and removal of the heating cartridge.
Solution Approach 2:
Thermal conductive elements are introduced as intermediary components between the heating cartridge and the protective tube. These intermediaries provide thermal conduction pathways while their specific design (such as compressed fiber mats or spring-loaded conductive plates) allows them to be compressible and removable, facilitating easy disassembly and reassembly.
2Power
If PTC element output is increased to improve heating performance, then heating capability is improved, but temperature stability deteriorates due to PTC's tendency to reduce output at higher temperatures
Solution Approach 1:
The thermal conductivity of the medium in the air gap is changed from low (air) to high (thermally conductive material), which fundamentally alters the heat transfer parameter. This enables more efficient heat transfer from the PTC element through the air gap, compensating for the PTC element's natural output reduction at higher temperatures and maintaining stable heating performance.
Solution Approach 2:
The improved thermal conduction creates a more responsive thermal feedback system where heat transfer rates more accurately reflect the temperature difference between the heating element and the surrounding medium. This enhanced feedback mechanism helps stabilize temperature control by providing more immediate thermal response to temperature changes.
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 ensures efficient heat transfer from the heating cartridge to the protective tube, allowing for easy replacement of the cartridge while maintaining the heating element's integrity, even under thermal expansion and contraction.
Implementation Method 1
The heat is then transferred from the heating cartridge, for example directly from an extruded profile or from a sheathing tube surrounding at least one extruded profile, to the protective tube via the at least one spring element. Because the contact surfaces of the spring element are pressed against the inside of the protective tube with a preload force, particularly effective heat transfer is achieved.
Implementation Method 2
Electric heating cartridges are commonly used, containing a heating wire or a PTC element as the heating element.
Data Source
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AI summary
The invention relates to a heating cartridge with a protective tube (2), in particular for heating solid cartridges in SCR systems. The heating cartridge (3) is inserted into the protective tube (2) at a distance therefrom, and the protective tube (2) contacts a medium to be heated on the outer face of the protective tube. According to the invention, at least one spring element (6, 66) which contacts the heating cartridge (3) and the protective tube (2) in a heat-conductive manner is inserted into an intermediate space between the heating cartridge (3) and the protective tube (2), and the spring element (6) has at least one surface pressing against the protective tube (2), said pressing surface being pressed elastically against the inner face of the protective tube (2) by the biasing force of the spring element (6, 66) in the assembled state.